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https://telescopes.desy.de/User_manual
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# Quick start manual
1. Install sensor planes and DUT(s) and measure distances
2. Switching on the hardware
• sensor cooling
• sensor power
• TLU and PMTs
• control and DAQ computers
3. Running EUDAQ
1. Starting run control components on RC PC
2. Starting senors and TLU components on NI crate
2. Jtagging Mimosa sensors (MI26.exe)
3. Starting EUDAQ NI and TLU producer
3. Configuring EUDAQ
4. Starting data taking ("Start" in EUDAQ)
4. Online monitoring of data taking
5. Switching off software and hardware
# Telescope
## Geometry and telescope resolution
The telescope is positioned on a supporting table (e.g. green DESY xy-support). Furthermore, it is possible to rotate the upper part of the telescope frame, in order to align all 6 telescope planes to the beam axis. This is important for alignment, however, it is usually aligned and users don't need to align the telescope.
The planes are counted from 0 upstream to 5 downstream. The sensor planes can be adjust according to the setup:
• The 3 upstream sensors (0, 1, 2) as well as the 3 downstream sensors (3, 4, 5) can be moved together on their rail on top of a sensor tower. It is recommended to move the rails in such a way that the distance of sensor 2 to the DUT and 3 to the DUT is as small as possible.
• The distances between the 3 sensors (upstream and downstream) can vary between a minimum of 2.5 cm and a maximum of 15 cm and the distance between the inner planes for integrating your DUT can be up to 50 cm at least. This geometry defines your telescope resolution. The best configuration (highest resolution) also depends on the thickness of the DUT ($X_0$) and the beam energy. Check out your specific geometry by reading/using:
Please measure the distance between each plane, measuring from one side of a plane to the same side of the following plane. This is important, if you analyse your data e.g. with EUTelescope.
## Material Budget
Test beam particles traverse:
• 2 scintillators
• 6 sensor planes
• 2 scintillators
A scintillator incorporates:
• 2-3 layers of 3M Vinyl tape (single thickness 0.177mm)
• 1 layer of 0.033mm thick PET radiant light film
• 3.0mm thick BC408 (scintillator)
• 1 layer of 0.033mm thick PET radiant light film
• 2-3 layers of 3M Vinyl tape (single thickness 0.177mm)
(Some scintillators are wrapped differently, using black shrinkable tubing e.g.).
A sensor plane incorporates:
# DUT integration
## Mechanical integration
The mechanical installation is quite flexible for the user. $$xy\phi$$-stages are provided for mounting the DUT and moving them remotely, see Hardware#PI-stages for moving DUTs. Find here a drawing of the angle with threads positions for mounting your DUT: File:Angle bracket.zip.
## EUDAQ integration
See, chapter 4 in the manual of EUDAQ#Introduction and Manual.
## PC integration in the local network
The telescope infrastructure provides a local network, typically in a format like 192.168.X.XXX. Telescope PCs have a fixed, manually assigned IP address. Users can integrate their PCs by setting a free IP address and connect their PC to the switch of the PC crate in the beam area or the switch located in the hut.
### Which IPs are free?
IPs of Telescope PCs, see the individual telescope pages (via Main Page).
Fast network check with nmap, e.g. for DATURA:
telescope@tb-datura:~$nmap -sP -PS22,3389 192.168.3.1/24 Starting Nmap 6.40 ( http://nmap.org ) at 2015-07-01 17:31 CEST Nmap scan report for 192.168.3.1 Host is up (0.00017s latency). Nmap scan report for 192.168.3.2 Host is up (0.00060s latency). Nmap scan report for 192.168.3.3 Host is up (0.00038s latency). Nmap scan report for 192.168.3.251 Host is up (0.00028s latency). Nmap done: 256 IP addresses (4 hosts up) scanned in 3.01 seconds ### Other helpful settings • Setting two IP's having one network card (in Ubuntu): sudo ifconfig eth0:1 192.168.x.xxx netmask 255.255.255.0 up # Switching on the hardware Usually the telescope is already turned on when you start data taking, but the situation might arise that the hardware is partially or completely turned off. Then you can refer to this section to make sure that you do it correctly. ## Sensors ### Cooling To switch on the minichiller: • Check the water level at the front panel. (The device stops cooling if the level is too low and will emit an alarm sound. Remember that the sound is probably not audible in the control room.) • Switch on the main switch. • Press and hold down the Set button • Adjust the temperature using the arrows to 15$^{\circ}$C (or higher if the ambient temperature is high) • Release the Set button • To start the pump press and hold the button on the right until it switches on ### Power To power the sensors in "standby" • Press the main power button of the power supply (Agilent E3644A) • Press the Recall button two times and see if 8 V is set already, otherwise.. • Press the Set Limits button. Verify the limit is 4.0 A on the power supply. • Set the voltage to 8 V. • Enable the output using the Output On/Off button. • Enable the green light button at the cable panel below the Agilent PS, see picture. • The currents will rise to approximately 2.0 A and later to 3.7 A when switching on the sensors, see below. Powering Mimosas at DESY's telescopes ## Trigger Logic Unit (TLU) and PMTs • Check USB connection to the NI crate and power supply at the rear side. • Check the PMT connections: power (4pin LEMO in "LV-Out") and signal (standard LEMO in "PM in"). ## Computers • Hardware#NI crate in the beam area • If the PC is off, switch on by pushing the white button in the the lower left corner of the front panel. • Login as telescope user (get the password from [email protected]). • Hardware#RunControl PC in the beam area • If the PC is off, switch on. • Login as telescope user (get the password from [email protected]). • Hardware#Terminal PC in the hut • If the PC is off, switch on. • Login as telescope user (get the password from [email protected]). # Running EUDAQ To start the data taking, all necessary telescope components of EUDAQ have to be running properly: run control, data- and log-collector, onlinemonitor and all hardware producers. We describe the standard runs to check, if the telescope is working: ni_autotrig.conf without beam and ni_coins.conf with beam. To run with a DUT or more, you have to integrate your DUT hardware, DAQ and EUDAQ producer - however, the procedure is analogous. Here in a nutshell, below in detail: 1. #Starting run control: ssh to RunControl, start ./STARTRUN.default 2. #Preparing hardware and starting EUDAQ producers • Mimosa26 sensors: remote desktop to NI crate • start MimosaDAQ.exe • Jtag: start MI26.exe, open mcf-file, press "All", "Read", "Start" • NI and TLU EUDAQ producers: start_EUDAQ_ni_tlu.bat 3. #Configuring EUDAQ: euRun: select conf-file and "Configure" 4. #Starting data taking: euRun: "Start" ## Starting run control For example at DATURA, From the Terminal PC in the hut, you can access remotely the Run Control PC which controls your data taking as well as store the data physically: • Open a terminal and connect to RunControl PC (192.168.3.1): ssh -X [email protected] • Start 4 EUDAQ components: euRun.exe, euLog.exe, TestDataCollector.exe, OnlineMonitor.exe: • cd eudaq • ./STARTRUN.default (Optionally, you can start the processes step-by-step manually; therefore, have a look in a STARTRUN-script.) If every component starts properly, you should see three windows: #### Troubleshootings • Not starting in general: Check, if the correct IP-address (NOT the computer name and NOT the localhost 127.0.0.1) is set as HOSTNAME in the STARTRUN-script or as option (-a / -r). • error while loading shared libraries: libCore.so.5.34: Root paths are missing, execute the following script to set the right PATH and LD_LIBRARY_PATH: setup_eudaq.sh or ilcsoft/v01-1X-XX/root/5.XX.XX/bin/thisroot.sh (with right version number instead of X's) • Problems with DataCollector: Check, if eudaq/data is a correct link to a writeable destination. ## Preparing hardware and starting EUDAQ producers Besides the EUDAQ run control, the EUDAQ producers for hardware components have to be running. We explain it for the Mimosa26 sensors (telescope planes) and for the TLU, however, it is the same procedure for a DUT or any other hardware: • Start hardware (power and DAQ). • Start EUDAQ producer communicating with hardware DAQ and EUDAQ run control. ### Mimosa26 sensors The Mimosa sensors are operated and read out by a FPGA and software infrastructure which is running on the NI crate. For example at DATURA at the Terminal PC: • Open Remmina (remote Desktop) and connect to NI crate (192.168.3.2) operated by Windows 7 #### 0. (Starting the FPGA) The FlexRIO board of the NI crate processes the Mimosa26 sensor data. Therefore, the FPGA has to be programmed correctly ("Download Bitfile to flash"). However, it is usually not necessary to flash the FPGA , since this will be usually done automatically, after booting the NI crate. If not, do the following: • Open "RIO Device Setup" • Select the "Resource" from the pull-down menu, usually "RIO0". • After clicking the folder icon, browse to the path of the bitfile "anemone.lvbitx". • Click the "Download Bitfile" button. • Select the "Device Settings" tab and select "Autoload VI on device powerup". • Click the "Apply Settings" button. • Click the "Exit" button. Now the NI-crate will load the bitfile to the FPGA, flash memory and run the FPGA. #### 1. Starting MimosaDAQ The "MimosaDAQ" is a LabView programme providing the communication between the FPGA onthe NI FlexRIO and the NI producer (EUDAQ producer for Mimosa26 sensors). You have to start it, before starting the NI producer: • Click on shortcut at Desktop "MimosaDAQ" (starts the program "anemone_v1.3.exe") • When opened, it should be running properly: black single arrow, white double arrow, red stop point. Here you find a documentation on the Anemone LabView interface: File:Artemsdocumentation.pdf ##### Troubleshootings • If a red light is on on the left, an error occured, and you should reset MimosaDAQ by clicking red stop point and twice double arrow. Known errors are e.g.: • "DataTransportListener" due to wrong TCP/IP settings in EUDAQ configuration • "ErrorConfig Socket" due to occupied port. • On the left, the fields after "MIMOSA_X" (X = 1, 2, 3, 4, 5, 6) displays the header of the Mimosa26 data, if EUDAQ processes data. It should be 55X555 for each sensor, otherwise, there is something wrong. #### 2. Starting sensor: MimosaJTAG The Mimosa26 sensors are programmed via JTAG using the parallel port of the NI-Crate. To program and start the sensors, the software "Mimosa36 JTAG Master Configuration" (MimosaJTAG) is used. During this process, it is recommended to check the sensor current by eye looking at the display of the sensors' Hardware#Power supply (in the area or via camera in the hut) or using a "Keysight BenchVue" software which can control and monitor the Hardware#Power supply via GPIB (at PC, e.g. in the hut): To start the sensors ("jtagging"), do the following: 1. The Hardware#Power supply for the Mimosa26 sensors and all supporting boards (Hardware#Sensors and periphery) should be switched on. If not, see #Power. The total current of the boards and 6 sensors is ~2.0 A (standby). 2. Open "MimosaJTAG" (using "Mi26.exe p:0x378" as command to avoid the pop-up window). Two windows will open, a main window (left) and a second window with all the register settings (right). For normal operation, the main window only is required. 3. Load a threshold mcf-file (threshold 5 or 6 is recommended): Click "Open" in "Master Configuration" section and select a file from the JTAG-folder. 4. Press "All", "Read" and "Start" (from right to left!) in "Device Update" : 1. Press "All" to send register settings to sensors, the current should increase to ~2.9 A ("All"). 2. Press "Read" to read registers as cross-check. The current should shortly change, but stay at ~2.9 A ("Read"). 3. Press "Start" to start the rolling shutter read-out of the sensors. The current should be at ~3.6 A ("Start"). Now you can start the NI producer (#3. Starting EUDAQ NI producer). After that, configuring (#Configuring EUDAQ) and starting EUDAQ (#Starting data taking), Mimosa26 data will also be processed and saved. 5. Repeat 3. and 4. for using another threshold. If you want to stop the sensors (see also #Switching off the hardware), press "Reset". The current should be ~2.0 A (standby). ##### Troubleshootings • Standby current is not ~2.0 A: Check if each plane has a standby current of ~300 mA by plugging in plane-by-plane. • Error(s) are read back during jtagging indicated at the bottom line of "MimosaJTAG" after pressing "Read": • Repeat: "Reset", "All", "Read" --> errors? • Power cycle: "Reset", switch Hardware#Power supply off and on, "All", "Read" --> errors? • Not starting, not reaching ~3.6 A: • Check if power supply is switched on. • Check connection of all power cables. • Check all RJ45 signal cables are properly connected to its connectors. • In any case never change the sensor order! #### 3. Starting EUDAQ NI and TLU producer After starting the MimosaDAQ (anemeone.vi LabView program) and starting the Sensors ("Jtagging"), you should start the NIProducer, which is the EUDAQ component running on the NI crate and communicating via TCP/IP to the run control (euRun.exe). Since the TLU is also connected to the NI crate via USB, usually you start both producers using a bat-script in the EUDAQ bin-folder or the link on the desktop containing: :: set the IP from RunControl PC set RUNCONTROL=192.168.X.1 start NIProducer.exe -r tcp://%RUNCONTROL%:44000 timeout /T 2 > nul start TLUProducer.exe -r tcp://%RUNCONTROL%:44000 This starts the NIProducer and the TLUProducer (EUDAQ component of Hardware#Trigger Logic Unit) on the NI crate. After a successful start, you will see the producers in the euRun.exe: ##### Troubleshootings • NIProducer or TLUProducer don't start and are not connecting to euRun.exe: Check the TCP/IP connection/communication: • Can you ping the run control (euRun.exe) from the NI crate and vice versa? • Is the environment variable RUNCONTROL correct (IP of run control PC with "euRun.exe")? • NIProducer or TLUProducer are not found: Check if you have a properly compiled EUDAQ version, see EUDAQ#Cmake options. ### DUT(s) ## Configuring EUDAQ After successfully starting all EUDAQ components and producers, EUDAQ components can be configured. Each component has options which are set in the config-files (*.conf) in the conf-folder. In the following, we explain two configurations: • ni_autotrig.conf: This is an important functionality test of the telescope. Using no beam, triggers produced by the TLU internally are sent to test the data taking (EUDAQ event building). • ni_coins.conf: This is the functionality test with beam. PMTs/scintillators in coincidence are used to produce triggers for event building. Both configurations can be used as template for DUT integration, EUDAQ with an integrated DUT is configured analogously. ### ni_autotrig.conf The content of the conf-file is: [RunControl] RunSizeLimit = 100000000 NoTrigWarnTime = 10 [DataCollector] [LogCollector] SaveLevel = EXTRA PrintLevel = INFO [Producer.TLU] OrMask = 0 VetoMask = 0 AndMask = 0 DutMask = 1 TriggerInterval = 1 TrigRollover = 0 [Producer.MimosaNI] NiIPaddr = 192.168.3.2 TriggerType = 1 Det = MIMOSA26 Mode = ZS2 NiVersion = 1 NumBoards = 6 OneFrame = 0 IDOffset = 0 MimosaID_1 = 1 MimosaID_2 = 2 MimosaID_3 = 3 MimosaID_4 = 4 MimosaID_5 = 5 MimosaID_6 = 6 MimosaEn_1 = 1 MimosaEn_2 = 1 MimosaEn_3 = 1 MimosaEn_4 = 1 MimosaEn_5 = 1 MimosaEn_6 = 1 The structure incorporates the names of each EUDAQ component (in brackets []), followed by the appropriate options. If a option is not in the file, EUDAQ will use the default value, which is hard-coded in the corresponding source code. The relevant options for autotriggering are: • TriggerInterval: If TriggerInterval is a nonzero value in units of milliseconds, the TLU produces triggers internally. The minimum value is 1, which provides a 1 kHz trigger rate. • DutMask: This option activates DUT interface channels at the TLU by using bit mask. Usually, the Hardware#Data reduction board of the Mimosa sensors is connected to the channel 0. Thus, running EUDAQ only reading out the sensors corresponds to a DutMask = 1. After pressing "Config" in euRun.exe, the RunControl and the MimosaDAQ change their state: ### ni_coins.conf To activate the external trigger inputs -- at the telescope, the inputs of the four PMTs/scintillators, the OrMask or the AndMask has to be activated: [Producer.TLU] OrMask = 0 VetoMask = 0 AndMask = 15 DutMask = 1 TriggerInterval = 0 TrigRollover = 0 TriggerInterval is set to 0, since triggers should now be produced by external input. Usually, a four-coincidence input is used, thus, AndMask = 15, see bit mask. ### Important options to adjust Besides the individual DUT options, the most important options for the user are: [RunControl] RunSizeLimit = 100000000 or [RunControl] RunEventLimit = 10000 RunSizeLimit sets the maximum size of raw data files in units of bytes. 100000000 corresponds to 100 MB, which is recommended by default. After reaching this file size, RunControl (euRun.exe) increments the run number automatically and creates a new raw data file. Or, you can also set RunEventLimit, which gives the events for a run, before starting the next run. [RunControl] NextConfigFileOnFileLimit = 1 Setting NextConfigFileOnFileLimit to 1 activates a "DUT parameter scan": After reaching a limit, RunControl will re-configure by using the next (alphabetically ordered) conf-file in the conf-folder. [DataCollector] FilePattern = "../data/run$6R\$X"
Using the FilePattern option, you can change the file name pattern and/or the data-directory, which is eudaq/data by default. At the moment, the OnlineMonitor only looks in the eudaq/data-folder, thus, it is recommended to use a soft link instead of the FilePattern option, e.g. for DATURA RunControl PC on which a Raid is mounted at /data2:
mkdir /data2/data_2015/YOUR_FOLDER
ln -e /data2/data_2015/YOUR_FOLDER /opt/eudaq/data
[Producer.MimosaNI]
NiIPaddr sets the IP address of the NI producer. Usually, this is already set in the default conf-files of the corresponding telescope setup.
[Producer.TLU]
DUTInput3 = LEMO
AndMask: If a PMT/scintillator device is not working (e.g. a "Scalers" value is not incrementing), you can deactivate a channel by setting the appropriate bit mask. DutMask: If you integrate your DUT and connect it to the Hardware#Trigger Logic Unit, you have to activate the corresponding channel, see bit mask. DUTInput: You can activate the DUT LEMO interfaces 0-3, here e.g. channel 3.
### Troubleshootings
• NIProducer crashes during configuring: Check the IP address in the EUDAQ conf-file. It should be the IP of the NI crate where the NIProducer is running:
[Producer.MimosaNI]
## Starting data taking
After successfully configuring all EUDAQ components and producers, EUDAQ data acquisition can be started by pressing "Start". If everything works correctly, "Triggers" and "Events Built" values are incrementing equally, e.g. for autotrigger data taking:
You can stop the data taking by "Stop", and e.g. reconfigure by selecting an updated conf-file and restart data taking "Start".
##### Troubleshootings
• No event building by EUDAQ ("Events Builts" is not incrementing):
• If "Trigger" are not incrementing, check if trigger logic (AndMask) is set correctly,
• Check if the headers are properly found by "MimosaDAQ", if "Trigger" are incrementing.
• Check connection of red data cables.
• Event size meter over 1000 and data taking is stopping after few seconds. The data flow of the sensor read-out is too hight, maybe due to:
• wrong Jtag files, broken pixel-columns not deactivated
• not working Aux board
• ao problem
# Online Monitoring
At the moment, the OnlineMon.exe only runs on Unix operation systems properly. Therefore, we recommend to run the euRun.exe, euLog.exe, TestDataCollector.exe and OnlineMon.exe on a Unix machine.
under construction
# Switching off software and hardware
You should ask [email protected] in which state you should set the telescope after test beam week. If necessary, you can power down the whole system.
## Stopping data taking
• "Stop" EUDAQ and "Terminate"
## Sensors
• Stopping sensors: On the NI crate, in the JTAG pgrogramm "MIMOSA26 JTAG Master Configuration", press "Reset" button in the bottom left corner.
• Switching off power: Press "ON/OFF" switch to set 0 V at the Agilent power supply. Press main switch.
• Cooling: Press main switch at the Huber minichiller.
## PI Stages
• Moving down $$y$$-stage: Use the software PIMikroMove.
• Switching off power of stages: Unplug the power of the $$x$$- and $$y$$-stage. Support the $$y$$ stage, it might be fall down, if there is a heavy DUT installation!
• Switching off power of controllers by unplugging.
## TLU
Unplug the power supply connector on the back.
## Computers
Remember to copy your data in eudaq/data-folder and your conf-files and maybe log-files!
You get the passwords from the coordinators ([email protected]). Choose remote or direct shutdown:
• NI crate (Windows)
• remotely: "teleuser" login via Remmina from Terminal PC and shutdown
• directly: "teleuser" login and shutdown
• Run Control PC (Ubuntu)
• remotely: "telescope-admin" login via "ssh 192.168.3.1" from Terminal PC and "sudo shutdown now"
• directly: "telescope" login and shutdown
In addition, set each main switch to off.
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http://mathhelpforum.com/algebra/172313-subtracting-negative-fraction-signs-cross-multiplication.html
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# Math Help - Subtracting from a negative fraction. (Signs in cross multiplication)
1. ## Subtracting from a negative fraction. (Signs in cross multiplication)
$-1 - \frac{1}{3}$
$- \frac{1 * 3}{1 * 3} - \frac{1}{3} = - \frac{3}{3} - \frac{1}{3} = - \frac{-3 - 1}{3} = - \frac{-4}{3} = ??$
does the negative sign on the faction mean that both the numerator and the denomanator shoud be treated as negative numbers when used in cross multiplication?
2. $-\frac{-4}{3}=(-1)\frac{-4}{3}=\frac{4}{3}$
3. -1-1/3 = -(1 + 1/3) = ?
Sometimes easier I find:
8 - 2/3 - 3/5 ; multiply by -1:
= -8 + 2/3 + 3/5
= -8 + 10/15 + 9/15
= -8 + 19/15
= -120/15 + 19/15 ; multiply by -1:
= 120/15 - 19/15
= 101/15
4. Originally Posted by DrSteve
$-\frac{-4}{3}=(-1)\frac{-4}{3}=\frac{4}{3}$
so
$-1 - \frac{1}{3} = \frac{4}{3}$ !?!
5. $- 1 - \frac{1}{3} = - \frac{1}{1} - \frac{1}{3} = - ( \frac{-1 * 3 - 1 * - 1}{ -1 * 3}) = -(\frac{(-3) - (-1)}{-3}) = -(\frac{-2}{-3}) = -(\frac{2}{3})= - \frac{2}{3}$ ???
6. Originally Posted by alyosha2
$-1 - \frac{1}{3}$
$- \frac{1 * 3}{1 * 3} - \frac{1}{3} = - \frac{3}{3} - \frac{1}{3} = - \frac{-3 - 1}{3} = - \frac{-4}{3} = ??$
does the negative sign on the faction mean that both the numerator and the denomanator shoud be treated as negative numbers when used in cross multiplication?
$-\frac{-4}{3}= \frac{4}{3}$
But " $- \frac{3}{3} - \frac{1}{3} = - \frac{-3 - 1}{3}$" is wrong.
You should have either $-\frac{3}{3}- \frac{1}{3}= \frac{-3- 1}{3}= \frac{-4}{3}$ or
$-\frac{3}{3}- \frac{1}{3}= -\frac{3+ 1}{3}= -\frac{4}{3}$
but not both!
And, of course, $-\frac{4}{3}= \frac{-4}{3}$.
7. Originally Posted by alyosha2
so
$-1 - \frac{1}{3} = \frac{4}{3}$ !?!
No. I was just simplifying $-\frac{-4}{3}$ for you. There are errors in your computation as other posters have already explained.
8. Originally Posted by HallsofIvy
$-\frac{-4}{3}= \frac{4}{3}$
But " $- \frac{3}{3} - \frac{1}{3} = - \frac{-3 - 1}{3}$" is wrong.
You should have either $-\frac{3}{3}- \frac{1}{3}= \frac{-3- 1}{3}= \frac{-4}{3}$ or
$-\frac{3}{3}- \frac{1}{3}= -\frac{3+ 1}{3}= -\frac{4}{3}$
but not both!
And, of course, $-\frac{4}{3}= \frac{-4}{3}$.
But I still don't understand how we are supposed to understand the negative sign in front of the fraction.
I understand what I'm supposed to have. I just don't understand why.
9. Originally Posted by alyosha2
But I still don't understand how we are supposed to understand the negative sign in front of the fraction
$-\dfrac{a}{b}=\dfrac{-a}{b}=\dfrac{a}{-b}$
$-\dfrac{3}{4}=\dfrac{-3}{4}=\dfrac{3}{-4}$
Does that help?
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https://unapologetic.wordpress.com/2010/07/12/
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# The Unapologetic Mathematician
## The Radon-Nikodym Chain Rule
Today we take the Radon-Nikodym derivative and prove that it satisfies an analogue of the chain rule.
If $\lambda$, $\mu$, and $\nu$ are totally $\sigma$-finite signed measures so that $\nu\ll\mu$ and $\mu\ll\lambda$, then $\lambda$-a.e. we have
$\displaystyle\frac{d\nu}{d\lambda}=\frac{d\nu}{d\mu}\frac{d\mu}{d\lambda}$
By the linearity we showed last time, if this holds for the upper and lower variations of $\nu$ then it holds for $\nu$ itself, and so we may assume that $\nu$ is also a measure. We can further simplify by using Hahn decompositions with respect to both $\lambda$ and $\mu$, passing to subspaces on which each of our signed measures has a constant sign. We will from here on assume that $\lambda$ and $\mu$ are (positive) measures, and the case where one (or the other, or both) has a constant negative sign has a similar proof.
Let’s also simplify things by writing
\displaystyle\begin{aligned}f&=\frac{d\nu}{d\mu}\\g&=\frac{d\mu}{d\lambda}\end{aligned}
Since $\mu$ and $\nu$ are both non-negative there is also no loss of generality in assuming that $f$ and $g$ are everywhere non-negative.
So, let $\{f_n\}$ be an increasing sequence of non-negative simple functions converging pointwise to $f$. Then monotone convergence tells us that
\displaystyle\begin{aligned}\lim\limits_{n\to\infty}\int\limits_Ef_n\,d\mu&=\int\limits_Ef\,d\mu\\\lim\limits_{n\to\infty}\int\limits_Ef_ng\,d\lambda&=\int\limits_Efg\,d\lambda\end{aligned}
for every measurable $E$. For every measurable set $F$ we find that
$\displaystyle\int\limits_E\chi_F\,d\mu=\mu(E\cap F)=\int\limits_{E\cap F}\,d\mu=\int\limits_{E\cap F}g\,d\lambda=\int\limits_E\chi_Fg\,d\lambda$
and so for all the simple $f_n$ we conclude that
$\displaystyle\int\limits_Ef_n\,d\mu=\int\limits_Ef_ng\,d\lambda$
Passing to the limit, we find that
$\displaystyle\nu(E)=\int\limits_E\,d\nu=\int\limits_Ef\,d\mu=\int\limits_Efg\,d\lambda$
and so the product $fg$ serves as the Radon-Nikodym derivative of $\nu$ in terms of $\lambda$, and it’s uniquely defined $\lambda$-almost everywhere.
July 12, 2010 Posted by | Analysis, Measure Theory | 10 Comments
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https://mathematica.stackexchange.com/questions/47305/alignment-in-columns
|
# Alignment in columns
I need to stack three objects on top of each other and align the first two to the center and the third one to the left. I've been trying to do this with Column, but it won't let me align the objects differently. The code below should make clear what I'm trying to do:
Column[{Style["Title", FontSize -> 20, "Title"],Graphics@Disk[],Style["Footnote text..."]},
{Center, Center, Left}]
I want the title and the disk to be centered, but the footnotes aligned to the left. Anyone know how to do this?
You can use Item to specify and individual alignment:
Column[{
Style["Title", FontSize -> 20, "Title"],
Graphics@Disk[],
Item[Style["Footnote text..."], Alignment -> Left]
},
Alignment -> Center]
or use the Alignment specification as per @Oska example. Remember that Column is a GridBox so also see Grid docs for a larger number of options examples.
Column[{
Style["Title", FontSize -> 20, "Title"],
Graphics@Disk[],
Style["Footnote text..."]
},
Alignment -> {Center, Center, {{-1, 1} -> Left}}]
• That way requires one less word. Thanks! – Mas May 5 '14 at 11:40
You can define a list of the expressions you want in your Column and an other, listAlign, of the placement that you wish:
list = {Style["Title", FontSize -> 20, "Title"], Graphics@Disk[], Style["Footnote text..."]};
listAlign = {Center, Center, Left};
Panel@Column[list, Alignment -> {{}, {},
Rule @@@ Thread[{{#, 1} & /@ Range@Length@list, listAlign}]}]
Then, working on a bigger list is much easier:
list = RandomChoice[{Style["Hello", FontSize -> 20, Bold],
Style["Hello"], Style["Hello", Tiny]}, 9]~Join~{"Bye"};
listAlign = RandomChoice[{Left, Center, Right}, 10];
Panel@Column[list,
Alignment -> {{}, {},
Rule @@@ Thread[{{#, 1} & /@ Range@Length@list, listAlign}]}]
• I see. So separate column every time I want to change the alignment.Thanks – Mas May 5 '14 at 11:36
• @Mas check the updated answer, it is now easier :) – Öskå May 5 '14 at 12:37
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http://openstudy.com/updates/558ac155e4b09ad72e966860
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anonymous one year ago Which colonial group was formed first? First Continental Congress Committees of Correspondence Stamp Act Congress Olive Branch Committee Delete Cancel Submit
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1. anonymous
• one year ago
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need help fast
2. jagr2713
• one year ago
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Hey what do you think will be the best answer?
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• one year ago
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a
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Correct The First Continental Congress was a meeting of delegates from twelve of the thirteen colonies that met on September 5 to October 26, 1774 at Carpenters' Hall in Philadelphia, Pennsylvania, early in the American Revolution. https://en.wikipedia.org/wiki/First_Continental_Congress $\huge{\color{purple}{\textbf{W}} \color{orange}{\cal{E}} \color{green}{\mathbb{L}} \color{blue}{\mathsf{C}} \color{maroon}{\rm{O}} \color{red}{\tt{M}} \color{gold}{\tt{E}} \space \color{orchid}{\mathbf{T}} \color{Navy}{\mathsf{O}} \space \color{OrangeRed}{\boldsymbol{O}} \color{Olive}{\mathbf{P}} \color{Lime}{\textbf{E}} \color{DarkOrchid}{\mathsf{N}} \color{Tan}{\mathtt{S}} \color{magenta}{\mathbb{T}} \color{goldenrod}{\mathsf{U}} \color{ForestGreen}{\textbf{D}} \color{Salmon}{\mathsf{Y}} \ddot \smile }$ if you want to know more about this site, Here is a tutorial about this site : http://openstudy.com/study#/updates/5525c0fce4b030ceb3f357e8
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• one year ago
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that not the right answer
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Opps sorry i gave the wrong answerD: I apologize Ok what do you think it would be
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• one year ago
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This should help https://en.wikipedia.org/wiki/Stamp_Act_Congress
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http://www.aimsciences.org/article/doi/10.3934/dcds.2016.36.683
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# American Institute of Mathematical Sciences
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February 2016, 36(2): 683-699. doi: 10.3934/dcds.2016.36.683
## Existence of solutions for a class of p-Laplacian type equation with critical growth and potential vanishing at infinity
1 Department of Mathematics, Huazhong Normal University, Wuhan 430079 2 Department of Mathematics and Statistics, Wright State University, Dayton, OH 45435, USA, United States 3 Department of Mathematics, Huazhong Normal University, Wuhan, 430079
Received July 2014 Revised February 2015 Published August 2015
In this paper, we study the existence of positive solution for the following p-Laplacain type equations with critical nonlinearity \begin{equation*} \left\{ \renewcommand{\arraystretch}{1.25} \begin{array}{ll} -\Delta_p u + V （x)|u|^{p-2}u = K(x)f(u)+P(x)|u|^{p^*-2}u, \quad x\in\mathbb{R}^N,\\ u \in \mathcal{D}^{1,p}(\mathbb{R}^N), \end{array} \right. \end{equation*} where $\Delta_p u = div(|\nabla u|^{p-2} \nabla u),\ 1 < p < N,\ p^* =\frac {Np}{N-p}$, $V(x)$, $K(x)$ are positive continuous functions which vanish at infinity, $f$ is a function with a subcritical growth, and $P(x)$ is a bounded, nonnegative continuous function. By working in the weighted Sobolev spaces, and using variational method, we prove that the given problem has at least one positive solution.
Citation: Yinbin Deng, Yi Li, Wei Shuai. Existence of solutions for a class of p-Laplacian type equation with critical growth and potential vanishing at infinity. Discrete & Continuous Dynamical Systems - A, 2016, 36 (2) : 683-699. doi: 10.3934/dcds.2016.36.683
##### References:
[1] C. O. Alves and M. A. S. Souto, Existence of solutions for a class of nonlinear Schrödinger equations with potentials vanishing at infinitly,, J. Diff. Eqns., 254 (2013), 1977. doi: 10.1016/j.jde.2012.11.013. Google Scholar [2] A. Ambrosetti, V. Felli and A. Malchiodi, Ground states of nonlinear Schrödinger equations with potentials vanishing at infinitly,, J. Eur. Math. Soc., 7 (2005), 117. doi: 10.4171/JEMS/24. Google Scholar [3] A. Ambrosetti and P. H. Rabinowitz, Dual varitional methods in critical point theory and applications,, J. Funct. Analysis, 14 (1973), 349. doi: 10.1016/0022-1236(73)90051-7. Google Scholar [4] A. Ambrosetti and Z. Q. Wang, Nonlinear Schrödinger equations with vanishing and decaying potentials,, Diff. Integ. Eqns., 18 (2005), 1321. Google Scholar [5] H. Brézis and E. Lieb, A relation between pointwise convergence of functions and convergence of functionals,, Proc. Amer. Math. Soc., 88 (1983), 486. doi: 10.1090/S0002-9939-1983-0699419-3. Google Scholar [6] H. Berestycki and P. L. Lions, Nonlinear scalar field equations. I. Existence of a ground state,, Arch. Ration. Mech. Anal., 82 (1983), 313. doi: 10.1007/BF00250555. Google Scholar [7] H. Brézis and L. Nirenberg, Positive solutions of nonlinear elliptic equations involving critical Sobolev exponents,, Commun. Pure. Appl. Math., 36 (1983), 437. doi: 10.1002/cpa.3160360405. Google Scholar [8] D. Bonheure and J. Van Schaftingen, Ground states for the nonlinear Schrödinger equation with potentials vanishing at infinitly,, Annali Mat. Pura Appl., 189 (2010), 273. doi: 10.1007/s10231-009-0109-6. Google Scholar [9] F. Catrina, M. Furtado and M. Montenegro, Positive solutions for nonlinear elliptic equations with fast increasing weights,, Proc. Roy. Soc. Edinb. A, 137 (2007), 1157. doi: 10.1017/S0308210506000795. Google Scholar [10] Y. B. Deng, The existence and nodal character of the solutions in $\mathbbR^N$ for semilinear elliptic equation involving critical Sobolev exponent,, Acta Math. Sci., 9 (1989), 385. Google Scholar [11] Y. B. Deng, L. Y. Jin and S. J. Peng, Solutions of Schrodinger Equations with Inverse Square Potential and Critical Nonlinearity,, J. Diff. Eqns., 253 (2012), 1376. doi: 10.1016/j.jde.2012.05.009. Google Scholar [12] Y. B. Deng, Z. H. Guo and G. S. Wang, Nodal solutions for $p-$Laplace equations with critical growth,, Nonlin. Analysis, 54 (2003), 1121. doi: 10.1016/S0362-546X(03)00129-9. Google Scholar [13] Y. B. Deng and Y. Li, On the existence of multiple positive solutions for a semilinear problem in exterior domains,, J. Diff. Eqns., 181 (2002), 197. doi: 10.1006/jdeq.2001.4077. Google Scholar [14] M. Escobedo and O. Kavian, Variational problems related to self-similar solutions of heat equations,, Nonlin Analysis, 11 (1987), 1103. doi: 10.1016/0362-546X(87)90001-0. Google Scholar [15] M. F. Furtado, J. P. P. da Silva and M. S. Xavier, Multiplicity of self-similar solutions for a critical equation,, J. Diff. Eqns., 254 (2013), 2732. doi: 10.1016/j.jde.2013.01.007. Google Scholar [16] G. B. Li, The existence of a weak solution of quasilinear elliptic equation with critical Sobolev exponent on unbounded domain,, Acta Math. Sci., 14 (1994), 64. Google Scholar [17] P. L. Lions, The concentration-compactness principle in calculus of variations, The limit case Part I,, Rev. Mat. Iber., 1 (1985), 145. doi: 10.4171/RMI/6. Google Scholar [18] P. L. Lions, The concentration-compactness principle in calculus of variations, The limit case Part II,, Rev. Mat. Iber., 1 (1985), 45. doi: 10.4171/RMI/12. Google Scholar [19] B. Opic and A. Kufner, Hardy-Type Inequalities,, Pitman Research Notes in Mathematics Series, (1990). Google Scholar [20] J. Serrin, Local behavior of solutions of quasilinear equations,, Acta. Math., 111 (1964), 247. doi: 10.1007/BF02391014. Google Scholar [21] D. Smets, Nonlinear Schrödinger equations with Hardy potential and critical nonlinearities,, Trans. Amer. Math. Soc., 357 (2005), 2909. doi: 10.1090/S0002-9947-04-03769-9. Google Scholar [22] W. A. Strauss, Existence of solitary in higher dimensions,, Commun. Math. Phys., 55 (1977), 149. doi: 10.1007/BF01626517. Google Scholar [23] C. A. Swanson and L. S. Yu., Critical p-laplacian problems in $\mathbbR^N$,, Annali Mat. Pura Appl., 169 (1995), 233. doi: 10.1007/BF01759355. Google Scholar [24] P. Tolksdorf, Regularity for a more general class of quasilinear elliptic equations,, J. Diff. Eqns., 51 (1984), 126. doi: 10.1016/0022-0396(84)90105-0. Google Scholar [25] M. Willem, Minimax Theorems,, Progress in Nonlinear Differential Equations and Their Applications, (1996). doi: 10.1007/978-1-4612-4146-1. Google Scholar [26] X. P. Zhu, Nontrivial solution of quasilinear elliptic equation involving critical Sobolev exponent,, Sci. Sinica., 31 (1990), 1161. Google Scholar
show all references
##### References:
[1] C. O. Alves and M. A. S. Souto, Existence of solutions for a class of nonlinear Schrödinger equations with potentials vanishing at infinitly,, J. Diff. Eqns., 254 (2013), 1977. doi: 10.1016/j.jde.2012.11.013. Google Scholar [2] A. Ambrosetti, V. Felli and A. Malchiodi, Ground states of nonlinear Schrödinger equations with potentials vanishing at infinitly,, J. Eur. Math. Soc., 7 (2005), 117. doi: 10.4171/JEMS/24. Google Scholar [3] A. Ambrosetti and P. H. Rabinowitz, Dual varitional methods in critical point theory and applications,, J. Funct. Analysis, 14 (1973), 349. doi: 10.1016/0022-1236(73)90051-7. Google Scholar [4] A. Ambrosetti and Z. Q. Wang, Nonlinear Schrödinger equations with vanishing and decaying potentials,, Diff. Integ. Eqns., 18 (2005), 1321. Google Scholar [5] H. Brézis and E. Lieb, A relation between pointwise convergence of functions and convergence of functionals,, Proc. Amer. Math. Soc., 88 (1983), 486. doi: 10.1090/S0002-9939-1983-0699419-3. Google Scholar [6] H. Berestycki and P. L. Lions, Nonlinear scalar field equations. I. Existence of a ground state,, Arch. Ration. Mech. Anal., 82 (1983), 313. doi: 10.1007/BF00250555. Google Scholar [7] H. Brézis and L. Nirenberg, Positive solutions of nonlinear elliptic equations involving critical Sobolev exponents,, Commun. Pure. Appl. Math., 36 (1983), 437. doi: 10.1002/cpa.3160360405. Google Scholar [8] D. Bonheure and J. Van Schaftingen, Ground states for the nonlinear Schrödinger equation with potentials vanishing at infinitly,, Annali Mat. Pura Appl., 189 (2010), 273. doi: 10.1007/s10231-009-0109-6. Google Scholar [9] F. Catrina, M. Furtado and M. Montenegro, Positive solutions for nonlinear elliptic equations with fast increasing weights,, Proc. Roy. Soc. Edinb. A, 137 (2007), 1157. doi: 10.1017/S0308210506000795. Google Scholar [10] Y. B. Deng, The existence and nodal character of the solutions in $\mathbbR^N$ for semilinear elliptic equation involving critical Sobolev exponent,, Acta Math. Sci., 9 (1989), 385. Google Scholar [11] Y. B. Deng, L. Y. Jin and S. J. Peng, Solutions of Schrodinger Equations with Inverse Square Potential and Critical Nonlinearity,, J. Diff. Eqns., 253 (2012), 1376. doi: 10.1016/j.jde.2012.05.009. Google Scholar [12] Y. B. Deng, Z. H. Guo and G. S. Wang, Nodal solutions for $p-$Laplace equations with critical growth,, Nonlin. Analysis, 54 (2003), 1121. doi: 10.1016/S0362-546X(03)00129-9. Google Scholar [13] Y. B. Deng and Y. Li, On the existence of multiple positive solutions for a semilinear problem in exterior domains,, J. Diff. Eqns., 181 (2002), 197. doi: 10.1006/jdeq.2001.4077. Google Scholar [14] M. Escobedo and O. Kavian, Variational problems related to self-similar solutions of heat equations,, Nonlin Analysis, 11 (1987), 1103. doi: 10.1016/0362-546X(87)90001-0. Google Scholar [15] M. F. Furtado, J. P. P. da Silva and M. S. Xavier, Multiplicity of self-similar solutions for a critical equation,, J. Diff. Eqns., 254 (2013), 2732. doi: 10.1016/j.jde.2013.01.007. Google Scholar [16] G. B. Li, The existence of a weak solution of quasilinear elliptic equation with critical Sobolev exponent on unbounded domain,, Acta Math. Sci., 14 (1994), 64. Google Scholar [17] P. L. Lions, The concentration-compactness principle in calculus of variations, The limit case Part I,, Rev. Mat. Iber., 1 (1985), 145. doi: 10.4171/RMI/6. Google Scholar [18] P. L. Lions, The concentration-compactness principle in calculus of variations, The limit case Part II,, Rev. Mat. Iber., 1 (1985), 45. doi: 10.4171/RMI/12. Google Scholar [19] B. Opic and A. Kufner, Hardy-Type Inequalities,, Pitman Research Notes in Mathematics Series, (1990). Google Scholar [20] J. Serrin, Local behavior of solutions of quasilinear equations,, Acta. Math., 111 (1964), 247. doi: 10.1007/BF02391014. Google Scholar [21] D. Smets, Nonlinear Schrödinger equations with Hardy potential and critical nonlinearities,, Trans. Amer. Math. Soc., 357 (2005), 2909. doi: 10.1090/S0002-9947-04-03769-9. Google Scholar [22] W. A. Strauss, Existence of solitary in higher dimensions,, Commun. Math. Phys., 55 (1977), 149. doi: 10.1007/BF01626517. Google Scholar [23] C. A. Swanson and L. S. Yu., Critical p-laplacian problems in $\mathbbR^N$,, Annali Mat. Pura Appl., 169 (1995), 233. doi: 10.1007/BF01759355. Google Scholar [24] P. Tolksdorf, Regularity for a more general class of quasilinear elliptic equations,, J. Diff. Eqns., 51 (1984), 126. doi: 10.1016/0022-0396(84)90105-0. Google Scholar [25] M. Willem, Minimax Theorems,, Progress in Nonlinear Differential Equations and Their Applications, (1996). doi: 10.1007/978-1-4612-4146-1. Google Scholar [26] X. P. Zhu, Nontrivial solution of quasilinear elliptic equation involving critical Sobolev exponent,, Sci. Sinica., 31 (1990), 1161. Google Scholar
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2018 Impact Factor: 1.143
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https://uk.arxiv.org/list/math/1609?skip=0&show=50
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# Mathematics
## Authors and titles for Sep 2016
[ total of 3157 entries: 1-50 | 51-100 | 101-150 | 151-200 | ... | 3151-3157 ]
[ showing 50 entries per page: fewer | more ]
[1]
Title: The Riemann zeta function and Gaussian multiplicative chaos: statistics on the critical line
Comments: Supersedes arXiv:1604.08378. Version 2 contains a limit theorem describing the mesoscopic behavior of the characteristic polynomial of random unitary matrices
Subjects: Probability (math.PR); Number Theory (math.NT)
[2]
Title: Stable Phase Retrieval in Infinite Dimensions
Subjects: Functional Analysis (math.FA)
[3]
Title: On continuous causal isomorphisms
Authors: Do-Hyung Kim
Subjects: Mathematical Physics (math-ph)
[4]
Title: Weak and strong approximation of semigroups on Hilbert spaces
Subjects: Functional Analysis (math.FA); Analysis of PDEs (math.AP)
[5]
Title: The status of the Zassenhaus conjecture for small groups
Subjects: Rings and Algebras (math.RA); Group Theory (math.GR); Representation Theory (math.RT)
[6]
Title: Reduced Open Gromov-Witten Invariants on K3 Surfaces and Multiple Cover Formula
Authors: Yu-Shen Lin
Subjects: Symplectic Geometry (math.SG); Algebraic Geometry (math.AG)
[7]
Title: Generalized solutions of Riccati equalities and inequalities
Comments: Published in Methods of Functional Analysis and Topology (MFAT), available at this http URL
Journal-ref: Methods Funct. Anal. Topology, Vol. 22 (2016), no. 2, 95-116
Subjects: Functional Analysis (math.FA)
[8]
Title: Pixel Arrays: A fast and elementary method for solving nonlinear systems
Subjects: Numerical Analysis (math.NA); Category Theory (math.CT)
[9]
Title: Full-Duplex Backscatter Interference Networks Based on Time-Hopping Spread Spectrum
Comments: submitted for possible journal publication
Journal-ref: IEEE Transactions on Wireless Communications, vol. 16, no. 7, pp. 4361-4377, Jul. 2017
Subjects: Information Theory (cs.IT)
[10]
Title: Rainbow Turán problems for paths and forests of stars
Subjects: Combinatorics (math.CO)
[11]
Title: On the essential minimum of Faltings' height
Comments: Following the referee's suggestions, we added a proof of the relation between the Arakelov theoretic description and Silverman's description of the Faltings height, we added a comment about the unstable Faltings height and we corrected definition (2.2), plus a few misprints. To appear in Mathematics of Computation
Subjects: Number Theory (math.NT); Algebraic Geometry (math.AG)
[12]
Title: A potential theoretic approach to Tanaka formula for asymmetric Lévy processes
Subjects: Probability (math.PR)
[13]
Title: Gaussian complex zeros on the hole event: the emergence of a forbidden region
Subjects: Complex Variables (math.CV); Mathematical Physics (math-ph); Probability (math.PR)
[14]
Title: Statistics on bargraphs viewed as cornerless Motzkin paths
Subjects: Combinatorics (math.CO)
[15]
Title: Quadratic Generated Normal Domains From Graphs
Subjects: Combinatorics (math.CO); Commutative Algebra (math.AC); Algebraic Geometry (math.AG)
[16]
Title: Representation of convex geometries by circles on a plane
Comments: 22 pages; 37 figures; Presented on Discrete Mathematics SIAM conference in Atlanta, US, June 6-10, 2016
Subjects: Combinatorics (math.CO)
[17]
Title: From geometry to geology: An invitation to mathematical pluralism through the phenomenon of independence
Authors: Jonas Reitz
Subjects: Logic (math.LO)
[18]
Title: Lech's conjecture in dimension three
Authors: Linquan Ma
Subjects: Commutative Algebra (math.AC)
[19]
Title: A mathematical consideration of vortex thinning in 2D turbulence
Authors: Tsuyoshi Yoneda
Subjects: Analysis of PDEs (math.AP); Fluid Dynamics (physics.flu-dyn)
[20]
Title: A Decomposition Method for Global Evaluation of Shannon Entropy and Local Estimations of Algorithmic Complexity
Comments: 39 pages, 46 with appendix. 15 figures total and 4 tables
Subjects: Information Theory (cs.IT); Computational Complexity (cs.CC)
[21]
Title: Jacobian elliptic Kummer surfaces and special function identities
Journal-ref: Commun. Number Theory Phys. 12 (2018), no. 1
Subjects: Algebraic Geometry (math.AG); Classical Analysis and ODEs (math.CA)
[22]
Title: Wiener index, Harary index and Hamiltonicity of graphs
Authors: Hongbo Hua, Bo Ning
Comments: 11 pages, finial version for publication in MATCH Commun. Math. Comput. Chem
Journal-ref: MATCH Commun. Math. Comput. Chem.78(2017) no.1, pp.153--162
Subjects: Combinatorics (math.CO)
[23]
Title: Optimal State Estimation with Measurements Corrupted by Laplace Noise
Subjects: Optimization and Control (math.OC); Systems and Control (eess.SY)
[24]
Title: On the non-vanishing conjecture and existence of log minimal models
Authors: Kenta Hashizume
Comments: 17 pages. final version. Remark 3.3 was added. To appear in Publ. Res. Inst. Math. Sci. arXiv admin note: text overlap with arXiv:1607.05005
Subjects: Algebraic Geometry (math.AG)
[25]
Title: Convergence rates and $W^{1,p}$ estimates in homogenization theory of Stokes systems in Lipschitz domains
Authors: Qiang Xu
Subjects: Analysis of PDEs (math.AP)
[26]
Title: Effective criteria for specific identifiability of tensors and forms
Comments: 31 pages, 2 Macaulay2 codes
Subjects: Algebraic Geometry (math.AG)
[27]
Title: On a class of conserved phase field systems with a maximal monotone perturbation
Subjects: Analysis of PDEs (math.AP); Optimization and Control (math.OC)
[28]
Title: Linear differential polynomials in zero-free meromorphic functions
Authors: J.K. Langley
Comments: This is the final version, accepted to appear in Ann. Acad. Sci. Fenn
Subjects: Complex Variables (math.CV)
[29]
Title: Asymptotic for the perturbed heavy ball system with vanishing damping term
Subjects: Optimization and Control (math.OC)
[30]
Title: Central measures on multiplicative graphs, representations of Lie algebras and weight polytopes
Authors: Cedric Lecouvey (LMPT), Pierre Tarrago (LMPT)
Comments: This version connects our results to those of Handelman and Pierce. It also gives a characterization of c-harmonic functions for the random Littelmann paths model considered
Subjects: Representation Theory (math.RT); Combinatorics (math.CO); Probability (math.PR)
[31]
Title: Multivariate Gaussian extended quadrature method of moments for turbulent disperse multiphase flow
Authors: Christophe Chalons (LM-Versailles), Frédérique Laurent (EM2C, FR3487), Marc Massot (EM2C, FR3487), Aymeric Vié (EM2C, FR3487)
Journal-ref: SIAM MMS, Vol. 15, Issue 4 (2017) 1553-1583
Subjects: Numerical Analysis (math.NA)
[32]
Title: On the Performance of Multihop-Intervehicular Communications Systems over n*Rayleigh Fading Channels
Journal-ref: IEEE Wireless Communications Letters (Volume: 5, Issue: 2, April 2016)
Subjects: Information Theory (cs.IT)
[33]
Title: Orbifold points on Prym-Teichmüller curves in genus four
Comments: 38 pages, 5 figures. For PARI files, see this http URL
Journal-ref: Journal of the Institute of Mathematics of Jussieu, Volume 18, Issue 4, July 2019, Pages 673-706
Subjects: Algebraic Geometry (math.AG); Geometric Topology (math.GT)
[34]
Title: Quasi-Galois theory in symmetric-monoidal categories
Authors: Bregje Pauwels
Journal-ref: Alg. Number Th. 11 (2017) 1891-1920
Subjects: Category Theory (math.CT); K-Theory and Homology (math.KT); Representation Theory (math.RT)
[35]
Title: Two-connected spanning subgraphs with at most $\frac{10}{7}$OPT edges
Subjects: Combinatorics (math.CO); Discrete Mathematics (cs.DM); Data Structures and Algorithms (cs.DS)
[36]
Title: Triple arrays from difference sets
Journal-ref: J. Combinatorial Designs 25 (2017), 494-506
Subjects: Combinatorics (math.CO)
[37]
Title: Lifting Weighted Blow-ups
Authors: Marco Andreatta
Comments: 11 pages, minor issues corrected. To appear in Revista Matematica Iberoamericana
Subjects: Algebraic Geometry (math.AG)
[38]
Title: Gradient Gibbs measures and fuzzy transformations on trees
Subjects: Probability (math.PR)
[39]
Title: Uniqueness for a class of stochastic Fokker-Planck and porous media equations
Authors: Michael Röckner, Francesco Russo (ENSTA ParisTech UMA)
Subjects: Probability (math.PR)
[40]
Title: Sharp L^p-L^r estimates for k-plane transforms in finite fields
Subjects: Classical Analysis and ODEs (math.CA)
[41]
Title: Smale's mean value conjecture for finite Blaschke products
Comments: To appear in an issue of Journal of Analysis denoted to the Proceedings of the Conference on Modern Aspects of Complex Geometry (MindaFest))
Subjects: Complex Variables (math.CV)
[42]
Title: Maximal function characterizations for new local Hardy type spaces on spaces of homogeneous type
Comments: 55 pages, to appear in Transactions of AMS
Subjects: Functional Analysis (math.FA); Analysis of PDEs (math.AP)
[43]
Title: Existence and asymptotic behavior of nontrivial solutions to the Swift-Hohenberg equation
Subjects: Classical Analysis and ODEs (math.CA); Analysis of PDEs (math.AP)
[44]
Title: Dual Capacity Upper Bounds for Noisy Runlength Constrained Channels
Authors: Andrew Thangaraj
Comments: Expanded version of a paper in IEEE Information Theory Workshop 2017, Cambridge, UK, Sep 11-14, 2017
Subjects: Information Theory (cs.IT)
[45]
Title: Hadamard property of the in and out states for Klein-Gordon fields on asymptotically static spacetimes
Comments: First part of a splitted and extended version of a manuscript which was originally arXiv:1603.07465; v2: various minor improvements, accepted in AHP
Subjects: Mathematical Physics (math-ph); High Energy Physics - Theory (hep-th); Analysis of PDEs (math.AP)
[46]
Title: A singular perturbation limit of diffused interface energy with a fixed contact angle condition
Journal-ref: Indiana Univ. Math. J. 67 No. 4 (2018), 1425-1437
Subjects: Analysis of PDEs (math.AP)
[47]
Title: The massive Feynman propagator on asymptotically Minkowski spacetimes
Comments: Second part of a splitted and extended version of a manuscript which was originally arXiv:1603.07465
Subjects: Mathematical Physics (math-ph); Analysis of PDEs (math.AP)
[48]
Title: Optimal point sets determining few distinct triangles
Comments: Version 2.0, 15 pages. Minor update
Subjects: Combinatorics (math.CO)
[49]
Title: On the complexity of failed zero forcing
Authors: Yaroslav Shitov
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|
https://codegolf.stackexchange.com/questions/178588/what-are-the-repeating-fibonacci-digits
|
# What are the repeating Fibonacci Digits?
As you probably know, a Fibonacci Number is one which is the sum of the previous two numbers in the series.
A Fibonacci Digit™ is one which is the sum of the two previous digits.
For instance, for the series beginning 1,1, the series would be 1,1,2,3,5,8,13,4,7,11,2... The change occurs after the 13, where, instead of adding 8+13, you add 1+3. The series loops at the end, where 4+7=11, and 1+1=2, same as the series starts.
For another example, the series beginning 2,2: 2,2,4,6,10,1,1,2,3,5,8,13,4,7,11,2,3.... This one starts out uniquely, but once the digits sum to 10, you end up with 1+0=1, 0+1=1, and the series continues - and loops - the same way the 1,1 series did.
# The Challenge
Given an integer input 0≤n≤99, calculate the loop in the Fibonacci Digit series beginning with those two digits. (You are certainly allowed to consider integers out of this range, but it's not required.) If given a one-digit input, your code should interpret it to denote the series beginning 0,n.
All numbers in the loop that are two-digits must be outputted as two digits. So, for instance, the loop for 1,1 would contain 13, not 1,3.
The output begins with the first number in the loop. So, based on the above restrictions, the loop for 1,1 begins with 2, since 1,1 and 11 are counted separately.
Each number of the output may be separated by whatever you want, as long as it's consistent. In all of my examples I use commas, but spaces, line breaks, random letters, etc. are all allowed, as long as you always use the same separation. So 2g3g5g8g13g4g7g11 is a legal output for 1, but 2j3g5i8s13m4g7sk11 is not. You can use strings, lists, arrays, whatever, provided that you have the correct numbers in the correct order separated by a consistent separator. Bracketing the entire output is also allowed (ex. (5,9,14) or [5,9,14], etc.).
Test Cases:
1 -> 2,3,5,8,13,4,7,11
2 -> 2,3,5,8,13,4,7,11
3 -> 11,2,3,5,8,13,4,7
4 -> 3,5,8,13,4,7,11,2
5 -> 2,3,5,8,13,4,7,11
6 -> 3,5,8,13,4,7,11,2
7 -> 14,5,9
8 -> 13,4,7,11,2,3,5,8
9 -> 11,2,3,5,8,13,4,7
0 -> 0
14 -> 5,9,14
59 -> 5,9,14
This is , so the lowest number of bytes wins.
• Can we take 2 digits as input, instead of $0\le n \le 99$? Jan 9 '19 at 17:47
• As in, take two inputs rather than one input that’s split? No. Jan 9 '19 at 17:48
• I still don't understand why 14 and 59 give the same result. If 59 is interpreted as starting 5,9 and allowing that as part of the loop then surely 14 should be the start of its loop?
– Neil
Jan 9 '19 at 21:23
• @williamporter The beginning of the sequence is 0,1,1,2,3,5,8,13,4,7,11,2,3. The first time that the loop repeats is at the second 2. Jan 9 '19 at 21:24
• @Neil The beginning of those respective sequences is 1,4,5,9,14,5 and 5,9,14,5,9. Both of them repeat beginning with the second 5. As I said earlier, only the input is split up; later numbers keep their digits together in the sequence. Jan 9 '19 at 21:25
# Jelly, 15 bytes
DFṫ-SṭḊ
d⁵ÇÐḶZḢ
Try it online!
### How it works
d⁵ÇÐḶZḢ Main link. Argument: n (integer)
d⁵ Divmod 10; yield [n:10, n%10].
ÇÐḶ Call the helper link until a loop is reached. Return the loop.
Z Zip/transpose the resulting array of pairs.
Ḣ Head; extract the first row.
DFṫ-SṭḊ Helper link. Argument: [a, b] (integer pair)
D Decimal; replace a and b with the digits in base 10.
F Flatten the resulting array of digit arrays.
ṫ- Tail -1; take the last two digits.
S Compute their sum.
Ḋ Dequeue; yield [b].
ṭ Append the sum to [b].
# Perl 6, 96 78 75 bytes
-3 bytes thanks to nwellnhof
{0,|.comb,((*~*)%100).comb.sum...{my$a=.tail(2);m/(\s$a.*)$a/}o{@_};$_&&$0} Try it online! 0 returns 0, and other number return a Match object which stringifies to the numbers separated by a space with a leading a trailing space. ### Explanation: { } # Anonymous code block 0,|.comb, ... # Start a sequence with 0,input # Where each element is .sum # The sum of ( %100).comb # The last two digits (*~*) # Of the previous two elements joined together # Until { }o{@_} # Pass the list into another function my$a=.tail(2); # Save the last two elements
m/(\s$a.*)$a/ # The list contains these elements twice?
# And return
;$_ # Input if input is 0 && # Else$0 # The looping part, as matched
# JavaScript (ES6), 111 104 103 bytes
f=(n,o=[p=n/10|0,n%10])=>n^o[i=o.lastIndexOf(n=(q=p+[p=n])/10%10+q%10|0)-1]?f(n,[...o,n]):o.slice(i,-1)
Try it online!
### Commented
f = ( // f = recursive function taking:
n, // n = last term, initialized to the input
o = [ // o = sequence, initially containing:
p = n / 10 | 0, // p = previous term, initialized to floor(n / 10)
n % 10 ] // n mod 10
) => //
n ^ // we compare n against
o[ // the element in o[] located at
i = o.lastIndexOf( // the index i defined as the last position of
n = // the next term:
(q = p + [p = n]) // q = concatenation of p and n; update p to n
/ 10 % 10 // compute the sum of the last two digits
+ q % 10 // of the resulting string
| 0 // and coerce it back to an integer
) - 1 // minus 1
] ? // if o[i] is not equal to n:
f(n, [...o, n]) // append n to o[] and do a recursive call
: // else:
o.slice(i, -1) // we've found the cycle: return it
# Python 3, 1871761581391381291211201129695120 116 bytes
f=lambda n,m=0,z=[]:(n,m)in zip(z,z[1:])and z[z.index(m)::-1]or f((z and n//10or m%10)+n%10,z and n or n//10,(m,*z))
Try it online!
Edit: As noted by @Jules, shorter solution applies to Python 3.6+. No longer distinct solutions for Python 3 / 3.6+
Edit: Indexing of z was too verbose. Without that now there is no gain in using eval.
Edit: Simplified finding if last two elements already appeared in the sequence.
Edit: Changed output format from list to tuple + replaced lambda with def
Edit: Back to lambda but embedded t into f.
Edit: Input n can be actually interpreted as head of growing collection z which would represent tail in recursive approach. Also beats @Arbo's solution again.
Edit: Actually you can unpack two items from head which cuts another 16 bytes.
Edit: Actually 17 bytes.
Edit: As noted by @Arbo solution was giving answers for 14 and 59 cases as they were in initial test cases which were proven later to be wrong. For now this isn't so short but at least it works correctly.
Quite an abuse of f-strings and eval. Original ungolfed code although I suspect it could be done somehow easier:
def is_subsequence(l1, l2):
N, n = len(l1), len(l2)
for i in range(N-n):
if l1[i:i+n]==l2:
return True
return False
def generate_sequence(r):
if is_subsequence(r,r[-2:]):
return r
last_two_digits = "".join(map(str,r))[-2:]
new_item = sum(int(digit) for digit in last_two_digits)
return generate_sequence(r + [new_item])
def f(n):
seq = generate_sequence([n,n])[::-1]
second_to_last = seq[1]
first_occurence = seq.index(second_to_last)
second_occurence = seq.index(second_to_last, first_occurence + 1)
return seq[first_occurence + 1 : second_occurence + 1][::-1]
• Small correction: this is Python 3.6+. This will plainly not work in 3.5 or older.
– 0xdd
Jan 9 '19 at 21:49
• Your testing code seems to not work; an input of 59 yields (14, 5, 9)
– ArBo
Jan 11 '19 at 23:38
• I see that test cases have changed since I began the challenge so that's why there was incorrect output. I've changed my solution so that it works but for now it's not so short. Nevertheless thanks for pointing that out. Jan 12 '19 at 10:25
# C (gcc), 114112 109 bytes
f(n,s){int i[19]={};for(s=n/10,n%=10;i[s]-n;n+=n>9?-9:s%10,s=i[s])i[s]=n;for(;printf("%d ",s),i[s=i[s]]-n;);}
Try it online!
-3 from ceilingcat
Includes a trailing space.
f(n,s){
int i[19]={}; //re-initialize edges for each call
for(s=n/10,n%=10; //initialize from input
i[s]-n; //detect loop when an edge s->n repeats
n+=n>9?-9:s%10,s=i[s])i[s]=n; //step
for(;printf("%d ",s),i[s=i[s]]-n;); //output loop
}
• huh, do...while doesn't need the braces if it's a single statement O_o Jan 12 '19 at 8:47
# Perl 5, 90 76 bytes
s/.\K/ /;s/(.?) *(.)\K$/$".($1+$2)/e until/^0|\b(.\B.|. .)\b.*(?= \1)/;$_=$&
TIO
• @JoKing, fixed and optimized Jan 10 '19 at 13:38
# Java (JDK), 194 bytes
n->"acdfinehlcdfinehfjofj".chars().map(x->x-97).skip((n="abbicbcsfibbbgqifiibbgbbbcsfbiiqcigcibiccisbcqbgcfbffifbicdqcibcbicfsisiibicfsiffbbicfsifiibicfsifii".charAt(n)%97)).limit(n<1?1:n<9?8:3)
Try it online!
Hardcoded seemed the shortest given that Python already had an answer of 187...
## Haskell, 100 bytes
d!p@(s,t)|(_,i:h)<-span(/=p)d=fst<$>i:h|q<-d++[p]=q!(t,last$mod s 10+t:[t-9|t>9])
h x=[]!divMod x 10
Try it online!
d!p@(s,t) -- function '!' recursively calculates the sequence
-- input parameter:
-- 'p': pair (s,t) of the last two numbers of the sequence
-- 'd': a list of all such pairs 'p' seen before
| <-span(/=p)d -- split list 'd' into two lists, just before the first
-- element that is equal to 'p'
(_,i:h) -- if the 2nd part is not empty, i.e. 'p' has been seen
-- before
=fst<\$>i:h -- return all first elements of that 2nd part. This is
-- the result.
|q<-d++[p] -- else (p has not been seen) bind 'q' to 'd' followed by 'p'
=q! -- and make a recursive call to '!' with 'q' and
(t, ) -- make the last element 't' the second to last element
-- the new last element is
[t-9|t>9] -- 't'-9 (digit sum of 't'), if 't'>9
mod s 10+t -- last digit of 's' plus 't', otherwise
h x= -- main function
[]!divMod x 10 -- call '!' with and empty list for 'd' and
-- (x/10,x%10) as the pair of last numbers
# Python 2, 123114 113 bytes
n=input()
p=b=l=n/10,n%10
while~-(b in p):p+=b,;l+=(b[1]/10or b[0]%10)+b[1]%10,;b=l[-2:]
print l[p.index(b)-2:-2]
Try it online!
The program builds up a tuple p of all 2-value pairs that have occurred in the sequence, which is initialised with junk to save some bytes. The sequence itself gets built in the tuple l, and the last two elements of this tuple are stored in b for easy (and short) reference. As soon as a repeat is found, we can look up the index of b in p to know where the loop began.
EDIT: Cleaned this up a bit, and shaved off one more byte... My method does seem to be nearing its byte count limit, and I really should stop working on this.
# Charcoal, 46 bytes
≔Ｅ◧Ｓ²ΣιθＷ¬υ≔ΦＥ⊖Ｌ⊞ＯθΣ…⮌⪫θω²✂θλＬθ¹⁼κ✂θ⊗⁻λＬθλ¹υＩυ
Try it online! Link is to verbose version of code. Explanation:
≔Ｅ◧Ｓ²Σιθ
Input the number, pad it to 2 characters, then take the digital sum of each character, and save the resulting list.
Ｗ¬υ
Repeat while the list of loops is empty.
⊞ＯθΣ…⮌⪫θω²
Calculate the sum of the two previous digits and add it to the Fibonacci list.
Ｅ⊖Ｌ...✂θλＬθ¹
Take all the nontrivial suffixes of the list.
≔Φ...⁼κ✂θ⊗⁻λＬθλ¹υ
Filter out those that don't repeat and save the result in the list of loops.
Ｉυ
Cast the list of loops to string and print.
# Red, 189178164 137 bytes
func[n][b: n % 10 c: reduce[a: n / 10]until[append c e: b
b: a *(pick[0 1]b > 9)+(a: b % 10)+(b / 10)k: find c reduce[e b]]take/last k k]
Try it online!
# Python 2, 149 139 bytes
s=input()
s=[s/10,s%10]
while zip(s,s[1:]).count((s[-2],s[-1]))<2:s+=[(s[-1]/10or s[-2]%10)+s[-1]%10]
print s[-s[::-1].index(s[-2],2)-1:-2]
Try it online!
Expects a non-negative integer as input. Smaller bytecount, but likely will no longer work for integers >99.
Explanation:
# get the input from STDIN
s=input()
# convert the input into two integers via a divmod operation
s=[s/10,s%10]
# count number of times the last two numbers appear in sequence in list.
# turn list into list of adjacent value pairs Ex: [1,1,2]->[(1,1),(1,2)]
zip(s,s[1:])
# count number of times the last two items in list appear in entire list
.count((s[-2],s[-1]))
# if >1 matches, we have found a repeat.
while .................................<2:
# the first digit of the last number, if it is >9
# else the last digit of the second to last number
(s[-1]/10or s[-2]%10)
# the last digit of the last number
+s[-1]%10
# add the new item to the list
s+=[..............................]
# reverse the list, then find the second occurrence of the second to last item
s[::-1].index(s[-2],2)
# get the section of the list from the second occurrence from the end, discard the final two items of the list
print s[-......................-1:-2]
# Husk, 15 bytes
UṠ-U_2¡ȯΣ↑_2ṁd;
Try it online!
UṠ-U_2¡ȯΣ↑_2ṁd;
U # longest prefix of unique elements from sequence
Ṡ-U_2 # (after removing longest prefix with
# all unique sublists of length 2)
¡ȯΣ↑_2ṁd; # fibonacci digit sequence:
¡ # repeatedly apply function to list
; # (starting with list formed from input):
ȯ # combination of 3 functions -
Σ # sum of
↑_2 # last 2 elements of
ṁd # digits of list
• Ṡ-U_2 is an interesting function. Nov 15 '20 at 16:18
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|
http://www.scstatehouse.gov/sess120_2013-2014/SJ14/20140318.htm
|
South Carolina General Assembly
120th Session, 2013-2014
Journal of the Senate
Tuesday, March 18, 2014
(Statewide Session)
Indicates Matter Stricken
Indicates New Matter
The Senate assembled at 12:00 Noon, the hour to which it stood adjourned, and was called to order by the PRESIDENT.
A quorum being present, the proceedings were opened with a devotion by the Chaplain as follows:
The Psalmist proclaims:
"Let them give thanks to the Lord for his unfailing love and his wonderful deeds. . .for he satisfies the thirsty and fills the hungry with good things." (Psalm 107:8-9)
Join me as we pray, please:
Loving God, we pray today that You grant to each of these Senators compassionate and caring hearts. So many of our South Carolina sisters and brothers have incredible needs, O Lord, as we all know. May these servants -- the members of this Body and their assistants -- all labor diligently to bring about brighter hopes and better lives for our people -- for all of our people. Likewise, may each of our other public servants also seek to honor You, dear Lord, doing so through their own efforts to satisfy basic thirsts and hungers. In Your loving name we pray, O Lord. Amen.
The PRESIDENT called for Petitions, Memorials, Presentments of Grand Juries and such like papers.
MESSAGE FROM THE GOVERNOR
The following appointments were transmitted by the Honorable Nikki Randhawa Haley:
Local Appointments
Initial Appointment, Abbeville County Magistrate, with the term to commence April 30, 2010, and to expire April 30, 2014
Philip D. Ray, 527 Noble Dr., Abbeville, SC 29620 VICE George T. Fergeson
Reappointment, Abbeville County Magistrate, with the term to commence April 30, 2014, and to expire April 30, 2018
Philip D. Ray, 527 Noble Dr., Abbeville, SC 29620
Reappointment, Horry County Board of Voter Registration, with the term to commence March 15, 2014, and to expire March 15, 2016
J. Michael Frazier, 731 Bucksport Rd., Conway, SC 29527
Reappointment, Horry County Board of Voter Registration, with the term to commence March 15, 2014, and to expire March 15, 2016
Maurice Jones, 4525 Canal Street, Loris, SC 29569
Doctor of the Day
Senator THURMOND introduced Dr. James McCoy, of North Charleston, S.C., Doctor of the Day.
Leave of Absence
On motion of Senator CAMPBELL at 12:05 P.M., Senator CAMPSEN was granted a leave of absence for today.
S. 865 (Word version) Sen. Shane Martin
INTRODUCTION OF BILLS AND RESOLUTIONS
The following were introduced:
S. 1124 (Word version) -- Senators Fair, Hutto and Jackson: A SENATE RESOLUTION TO RECOGNIZE THAT ABUSE AND NEGLECT OF CHILDREN IS A SIGNIFICANT PROBLEM AND TO DECLARE TUESDAY, APRIL 8, 2014, AS "CHILDREN'S ADVOCACY DAY" IN SOUTH CAROLINA.
l:\council\bills\bh\26105dg14.docx
Senator FAIR spoke on the Resolution.
S. 1125 (Word version) -- Senator Hayes: A SENATE RESOLUTION TO RECOGNIZE THE RIGHTS OF CITIZENS WITH DOWN SYNDROME, TO PROMOTE THEIR INCLUSION AND WELL-BEING, AND TO DECLARE MARCH 21, 2014, AS "DOWN SYNDROME DAY" IN SOUTH CAROLINA.
l:\council\bills\rm\1525ahb14.docx
S. 1126 (Word version) -- Senator Bennett: A CONCURRENT RESOLUTION TO CONGRATULATE RACHEL REYNOLDS ON HER GRADUATION FROM SUMMERVILLE HIGH SCHOOL, TO COMMEND HER FOR HER COURAGE, AND TO WISH HER THE RICHEST BLESSINGS OF GOD IN THE DAYS AHEAD.
l:\council\bills\rm\1529dg14.docx
The Concurrent Resolution was adopted, ordered sent to the House.
S. 1127 (Word version) -- Senator Hutto: A BILL TO AMEND THE CODE OF LAWS OF SOUTH CAROLINA, 1976, BY ADDING SECTION 17-5-140 SO AS TO PROVIDE THAT THE FUNDS FROM THE SURCHARGE IMPOSED PURSUANT TO SECTION 44-63-84 MUST BE DISBURSED TO THE COUNTIES EQUALLY TO PAY THE DULY ELECTED FULL-TIME CORONER OR OTHER RELATED PERSONNEL OR EQUIPMENT AND TO PROVIDE THAT EXCESS FUNDS MUST BE USED BY THE CORONERS TRAINING ADVISORY COMMITTEE TO PERFORM ITS DUTIES; TO AMEND SECTION 17-5-130, AS AMENDED, RELATING TO THE CORONERS TRAINING ADVISORY COMMITTEE, SO AS TO PROVIDE ADDITIONAL DUTIES; AND TO AMEND SECTION 44-63-84, RELATING TO THE ISSUANCE OF A DEATH CERTIFICATE, SO AS TO IMPOSE A FIVE DOLLAR SURCHARGE FOR THE ISSUANCE OF AN INITIAL DEATH CERTIFICATE AND THREE DOLLARS FOR EACH SUBSEQUENT DEATH CERTIFICATE.
l:\council\bills\bh\26111dg14.docx
Read the first time and referred to the Committee on Judiciary.
S. 1128 (Word version) -- Senator Leatherman: A BILL TO AMEND SECTION 61-4-1100, CODE OF LAWS OF SOUTH CAROLINA, 1976, RELATING TO PROHIBITED PRACTICES OF BEER PRODUCERS AND WHOLESALERS, SO AS TO PROHIBIT A BEER PRODUCER FROM SELLING BEER TO A BEER WHOLESALER IN THIS STATE AT A PRICE DIFFERENT FROM THAT CHARGED OTHER BEER WHOLESALERS IN THIS STATE, TO PROHIBIT A BEER PRODUCER FROM REQUIRING A BEER WHOLESALER TO PARTICIPATE IN AN ADVERTISING CAMPAIGN, AND TO PROHIBIT A BEER PRODUCER FROM WITHDRAWING FUNDS FROM A BEER WHOLESALER'S BANK ACCOUNT WITHOUT THE WHOLESALER'S WRITTEN CONSENT.
l:\council\bills\dka\3164jh14.docx
Read the first time and referred to the Committee on Judiciary.
S. 1129 (Word version) -- Senator Young: A BILL TO AMEND CHAPTER 3, TITLE 7 OF THE SOUTH CAROLINA CODE OF LAWS, 1976, RELATING TO THE STATE ELECTION COMMISSION, BY ADDING SECTION 7-3-80 TO PROVIDE THE AUTHORITY FOR THE COMMISSION TO ESTABLISH REGULATIONS RELATED TO THE CONDUCT OF POST ELECTION AUDITS PRIOR TO CERTIFICATION OF ELECTIONS, AND TO REQUIRE AUDIT DATA BE MADE PUBLIC; AND TO AMEND CHAPTER 13, TITLE 7, RELATING TO CONDUCT OF ELECTIONS, BY ADDING SECTION 7-13-1155, TO REQUIRE COUNTY ELECTION COMMISSIONS OR COUNTY BOARDS OF REGISTRATION AND ELECTIONS TO PERFORM POST ELECTION AUDITS BEFORE THE CERTIFICATION OF AN ELECTION.
l:\s-jud\bills\young\jud0102.rem.docx
Read the first time and referred to the Committee on Judiciary.
S. 1130 (Word version) -- Labor, Commerce and Industry Committee: A JOINT RESOLUTION TO APPROVE REGULATIONS OF THE BUILDING CODES COUNCIL, RELATING TO IRC SECTION R312.2 WINDOW FALL PROTECTION, DESIGNATED AS REGULATION DOCUMENT NUMBER 4435, PURSUANT TO THE PROVISIONS OF ARTICLE 1, CHAPTER 23, TITLE 1 OF THE 1976 CODE.
l:\council\bills\dbs\31155ac14.docx
Read the first time and ordered placed on the Calendar without reference.
S. 1131 (Word version) -- Senator Shealy: A SENATE RESOLUTION TO RECOGNIZE AND HONOR PATSY RAUTON LIGHTLE OF LEXINGTON FOR THIRTY-FIVE YEARS OF OUTSTANDING SERVICE AS A STATE LAW ENFORCEMENT DIVISION (SLED) AGENT, CHILD AND VULNERABLE ADULT ADVOCATE, AND PROFESSIONAL EDUCATOR, AND TO CONGRATULATE HER FOR HER UNTIRING EFFORTS TO ENHANCE THE INVESTIGATION AND PROSECUTION OF ABUSE AND THE QUALITY AND SAFETY OF LIFE FOR OUR VOICELESS VICTIMS.
l:\s-res\ks\037pats.mrh.ks.docx
S. 1132 (Word version) -- Senator Sheheen: A BILL TO AMEND THE CODE OF LAWS OF SOUTH CAROLINA, 1976, BY ADDING ARTICLE 5 TO CHAPTER 25, TITLE 16 SO AS TO ENACT THE "TEEN DATING VIOLENCE PREVENTION ACT", TO DEFINE NECESSARY TERMS, CREATE THE OFFENSE OF TEEN DATING VIOLENCE, PROVIDE A PENALTY, ALLOW VICTIMS TO SEEK ORDERS OF PROTECTION OR RESTRAINING ORDERS UNDER CERTAIN CIRCUMSTANCES, AND PROHIBIT A PERSON WHO VIOLATES THE PROVISIONS OF THE SECTION FROM PARTICIPATING IN A PRETRIAL INTERVENTION PROGRAM; TO AMEND SECTION 59-32-10, RELATING TO DEFINITIONS FOR PURPOSES OF THE COMPREHENSIVE HEALTH EDUCATION ACT, SO AS TO DEFINE THE TERM "TEEN DATING VIOLENCE"; AND TO AMEND SECTIONS 59-32-20, 59-32-30, AND 59-32-50, ALL RELATING TO THE REQUIREMENTS OF THE COMPREHENSIVE HEALTH EDUCATION ACT, ALL SO AS TO REQUIRE THE INCLUSION OF TEEN DATING VIOLENCE EDUCATION IN THE COMPREHENSIVE HEALTH EDUCATION CURRICULUM AND MAKE CONFORMING CHANGES.
l:\council\bills\dka\3163ahb14.docx
Read the first time and referred to the Committee on Judiciary.
REPORTS OF STANDING COMMITTEES
Senator COURSON from the Committee on Education submitted a majority favorable with amendment and Senator HUTTO a minority unfavorable report on:
S. 93 (Word version) -- Senator Young: A BILL TO AMEND SECTION 59-112-20 OF THE 1976 CODE, RELATING TO RATES OF TUITION AND FEES TO BE PAID BY STUDENTS ENTERING OR ATTENDING STATE INSTITUTIONS, TO PROVIDE FOR IN-STATE TUITION RATES TO ELIGIBLE PERSONS FUNDING THEIR POST-SECONDARY EDUCATION OR TRAINING WITH THE UNITED STATES DEPARTMENT OF VETERANS AFFAIRS GI BILL.
Ordered for consideration tomorrow.
Senator COURSON from the Committee on Education submitted a majority favorable with amendment and Senator HUTTO a minority unfavorable report on:
H. 3086 (Word version) -- Reps. Daning, J.E. Smith, Crosby, R.L. Brown, M.S. McLeod, Taylor, J.R. Smith, Wells, Hixon, Rivers and Gilliard: A BILL TO AMEND SECTION 59-112-50, AS AMENDED, CODE OF LAWS OF SOUTH CAROLINA, 1976, RELATING TO IN-STATE TUITION RATES FOR MILITARY PERSONNEL AND THEIR DEPENDENTS UNDER CERTAIN CONDITIONS, SO AS TO REVISE THE CRITERIA UNDER WHICH VETERANS WHO ARE HONORABLY DISCHARGED AND THEIR DEPENDENTS MAY RECEIVE IN-STATE TUITION RATES.
Ordered for consideration tomorrow.
Senator COURSON from the Committee on Education submitted a favorable with amendment report on:
H. 3919 (Word version) -- Reps. Owens, Bowen, Patrick, Taylor, Anderson, Allison, Brannon, Loftis, Ballentine, Rivers, Huggins, Knight, Simrill, King, Willis, Whitmire, McCoy, Anthony, Crosby, Neal, Clyburn, Barfield, Bedingfield, R.L. Brown, Cobb-Hunter, George, Hayes, Hiott, Hixon, Hosey, Lucas, Pope, Putnam, G.R. Smith, Wells, Wood, Whipper, Mitchell, Robinson-Simpson and Dillard: A BILL TO AMEND SECTION 59-18-310, AS AMENDED, CODE OF LAWS OF SOUTH CAROLINA, 1976, RELATING TO THE EXIT EXAM REQUIRED FOR HIGH SCHOOL GRADUATION, SO AS TO PROVIDE THAT ALL STUDENTS MUST TAKE THE EXIT EXAM TO GRADUATE BUT NEED NOT ATTAIN ANY MINIMUM SCORE ON THE EXIT EXAM TO GRADUATE, TO PROVIDE AN ELIGIBLE STUDENT WHO PREVIOUSLY FAILED TO RECEIVE A HIGH SCHOOL DIPLOMA OR WAS DENIED GRADUATION SOLELY FOR FAILING THE EXIT EXAM MAY REENROLL IN HIGH SCHOOL AND WILL NOT HAVE TO PASS THE EXIT EXAM TO RECEIVE A HIGH SCHOOL DIPLOMA, AND TO REQUIRE THE DEPARTMENT OF EDUCATION TO REMOVE ANY CONFLICTING REQUIREMENTS AND PROMULGATE CONFORMING CHANGES IN ITS APPLICABLE REGULATIONS; TO AMEND SECTION 59-48-35, RELATING TO REQUIREMENTS FOR A DIPLOMA FROM THE SPECIAL SCHOOL OF SCIENCE AND MATHEMATICS, AND SECTION 59-139-60, RELATING TO THE DUTY OF THE STATE BOARD OF EDUCATION TO REVIEW STUDENT PERFORMANCE ON ASSESSMENT TESTING AND TO MONITOR THE PERFORMANCE OF SCHOOLS AND SCHOOL DISTRICTS, ALL SO AS TO MAKE CONFORMING CHANGES; AND TO CREATE THE HIGH SCHOOL ASSESSMENT STUDY COMMITTEE TO CONSIDER WHETHER THE HIGH SCHOOL ASSESSMENT PROGRAM SHOULD REMAIN THE ACCOUNTABILITY ASSESSMENT USED BY THE STATE AND TO RECOMMEND AN ALTERNATIVE IF NECESSARY, TO PROVIDE FOR THE COMPOSITION AND STAFFING OF THE STUDY COMMITTEE, TO REQUIRE THE COMMITTEE REPORT CERTAIN INFORMATION TO THE GENERAL ASSEMBLY, AND TO PROVIDE FOR THE TERMINATION OF THE STUDY COMMITTEE.
Ordered for consideration tomorrow.
THE SENATE PROCEEDED TO A CALL OF THE UNCONTESTED LOCAL AND STATEWIDE CALENDAR.
RETURNED TO THE HOUSE
H. 3231 (Word version) -- Reps. Atwater, Huggins, Toole, Ballentine, Taylor, Bingham, Pitts and Wood: A BILL TO AMEND THE CODE OF LAWS OF SOUTH CAROLINA, 1976, BY ADDING SECTION 57-1-90 SO AS TO PROVIDE THAT THE DEPARTMENT OF TRANSPORTATION SHALL NOT DISCRIMINATE AGAINST MOTORCYCLES, MOTORCYCLE OPERATORS, OR MOTORCYCLE PASSENGERS.
The Senate proceeded to a consideration of the Bill, the question being the third reading of the Bill.
Motion Under Rule 26B
Senator GROOMS asked unanimous consent to make a motion to take up further amendments pursuant to the provisions of Rule 26B.
There was no objection.
Senator GROOMS proposed the following amendment (3231R001.LKG), which was adopted:
Amend the bill, as and if amended, page 2, by striking line 4 and inserting:
/ for full-size vehicles.
(C) As used in this section, 'reasonable accommodations' shall not be interpreted to include, require, or otherwise mandate the structural or technological modification of parking structures constructed or substantially completed before July 1, 2014." /
Renumber sections to conform.
Amend title to conform.
Senator GROOMS explained the amendment.
The question then was third reading of the Bill.
The "ayes" and "nays" were demanded and taken, resulting as follows:
Ayes 35; Nays 0
AYES
Alexander Allen Bennett
Bright Bryant Cleary
Coleman Corbin Courson
Cromer Davis Fair
Gregory Grooms Hayes
Johnson Kimpson Leatherman
Lourie Malloy Martin, Larry
Martin, Shane Massey McElveen
McGill Nicholson O'Dell
Peeler Scott Setzler
Shealy Thurmond Turner
Verdin Young
Total--35
NAYS
Total--0
There being no further amendments, the Bill was read the third time, passed and ordered returned to the House of Representatives with amendments.
H. 3231--Recorded Vote
Senator CAMPBELL desired to be recorded as voting in favor of third reading of the Bill.
The following Bills and Joint Resolution were read the third time and ordered sent to the House of Representatives:
S. 1007 (Word version) -- Senators Campbell and O'Dell: A BILL TO AMEND THE CODE OF LAWS OF SOUTH CAROLINA, 1976, BY ADDING SECTION 29-3-625 SO AS TO PROVIDE A PROCESS FOR EXPEDITING MORTGAGE FORECLOSURES AND TO DEFINE NECESSARY TERMINOLOGY.
S. 1075 (Word version) -- Labor, Commerce and Industry Committee: A JOINT RESOLUTION TO APPROVE REGULATIONS OF THE DEPARTMENT OF LABOR, LICENSING AND REGULATION - OFFICE OF STATE FIRE MARSHAL, RELATING TO OFFICE OF STATE FIRE MARSHAL, DESIGNATED AS REGULATION DOCUMENT NUMBER 4378, PURSUANT TO THE PROVISIONS OF ARTICLE 1, CHAPTER 23, TITLE 1 OF THE 1976 CODE.
S. 985 (Word version) -- Senator Cleary: A BILL TO AMEND THE CODE OF LAWS OF SOUTH CAROLINA, 1976, BY ADDING ARTICLE 6 TO CHAPTER 1, TITLE 6, TO ENACT THE "FAIRNESS IN LODGING ACT" SO AS TO ALLOW MUNICIPALITIES AND COUNTIES BY ORDINANCE TO IMPLEMENT ADDITIONAL ENFORCEMENT PROVISIONS FOR THE BUSINESS LICENSE TAX AND THE LOCAL ACCOMMODATIONS TAX AS THOSE PROVISIONS APPLY TO THE OWNERS OF RESIDENTIAL REAL PROPERTY WHO RENT THE PROPERTY TO TOURISTS, INCLUDING DATA SHARING WITH THE SOUTH CAROLINA DEPARTMENT OF REVENUE, SPECIFIC NOTICE TO PROPERTY OWNERS INCLUDED IN PROPERTY TAX BILLS, AN ADDITIONAL PENALTY THAT MAY BE IMPOSED FOR NONCOMPLIANCE AFTER THE RECEIPT OF SUCH A NOTICE, AND DIRECTIONS TO THE SOUTH CAROLINA DEPARTMENT OF REVENUE TO IDENTIFY "RENTAL BY OWNER" WEBSITES ADVERTISING TOURISTS RENTALS AND REQUEST THEM TO POST ON THE WEBSITES A STATEMENT REGARDING THE LEGAL OBLIGATIONS OF THE OWNERS OF PROPERTY IN THIS STATE LISTED ON THE WEBSITE, TO PAY ALL APPLICABLE LOCAL AND STATE TAXES AND FEES WITH RESPECT TO SUCH RENTALS; AND TO AMEND SECTIONS 6-1-120, 12-54-240, AS AMENDED, AND 12-4-310, RELATING RESPECTIVELY TO THE CONFIDENTIALITY OF LOCAL AND STATE TAX DATA AND EXCEPTIONS THERETO, AND THE DUTIES OF THE SOUTH CAROLINA DEPARTMENT OF REVENUE, SO AS TO CONFORM THEM TO THE PROVISIONS OF THIS ACT.
S. 1034 (Word version) -- Senator L. Martin: A JOINT RESOLUTION TO ADOPT REVISED CODE VOLUMES 5 AND 8 OF THE CODE OF LAWS OF SOUTH CAROLINA, 1976, TO THE EXTENT OF THEIR CONTENTS, AS THE ONLY GENERAL PERMANENT STATUTORY LAW OF THE STATE AS OF JANUARY 1, 2014.
The Senate proceeded to a consideration of the Resolution, the question being the second reading of the Joint Resolution.
Senator MASSEY explained the Joint Resolution.
The question then was second reading of the Joint Resolution.
The "ayes" and "nays" were demanded and taken, resulting as follows:
Ayes 36; Nays 0
AYES
Alexander Bennett Bright
Bryant Campbell Cleary
Corbin Courson Cromer
Davis Fair Gregory
Grooms Hayes Hembree
Johnson Kimpson Leatherman
Malloy Martin, Larry Martin, Shane
Massey McElveen McGill
Nicholson O'Dell Peeler
Scott Setzler Shealy
Sheheen Thurmond Turner
Verdin Williams Young
Total--36
NAYS
Total--0
The Joint Resolution was read the second time and ordered placed on the Third Reading Calendar.
H. 3784 (Word version) -- Reps. J.E. Smith, Pitts, Vick and Harrell: A BILL TO AMEND SECTION 59-114-30, AS AMENDED, CODE OF LAWS OF SOUTH CAROLINA, 1976, RELATING TO THE NATIONAL GUARD COLLEGE ASSISTANCE PROGRAM, SO AS TO CLARIFY THAT EACH ACADEMIC YEAR'S ANNUAL MAXIMUM GRANT MUST BE BASED ON THE AMOUNT OF AVAILABLE PROGRAM FUNDS; TO AMEND SECTION 59-114-40, AS AMENDED, RELATING TO THE NATIONAL GUARD COLLEGE ASSISTANCE PROGRAM QUALIFICATION REQUIREMENTS, SO AS TO PROVIDE THAT NATIONAL GUARD MEMBERS BECOME ELIGIBLE FOR COLLEGE ASSISTANCE PROGRAM GRANTS UPON COMPLETION OF BASIC TRAINING AND ADVANCED INDIVIDUAL TRAINING; AND TO AMEND SECTION 59-114-65, RELATING TO GRANT AVAILABILITY, SO AS TO ALLOW APPROPRIATIONS TO THE NATIONAL GUARD COLLEGE ASSISTANCE PROGRAM TO BE CARRIED FORWARD TO A SUBSEQUENT FISCAL YEAR AND EXPENDED FOR THE SAME PURPOSE, AND TO EXEMPT APPROPRIATIONS TO THE NATIONAL GUARD COLLEGE ASSISTANCE PROGRAM FROM MIDYEAR BUDGET REDUCTIONS.
The Senate proceeded to a consideration of the Bill, the question being the second reading of the Bill.
Senator SETZLER explained the Bill.
The question then was second reading of the Bill.
The "ayes" and "nays" were demanded and taken, resulting as follows:
Ayes 33; Nays 0
AYES
Alexander Allen Bennett
Bright Bryant Campbell
Cleary Corbin Courson
Cromer Davis Fair
Gregory Grooms Hayes
Hembree Johnson Kimpson
Malloy Martin, Larry Martin, Shane
McGill Nicholson O'Dell
Peeler Scott Setzler
Shealy Sheheen Thurmond
Turner Verdin Williams
Total--33
NAYS
Total--0
The Bill was read the second time and ordered placed on the Third Reading Calendar.
H. 3784--Recorded Vote
Senators MASSEY and YOUNG desired to be recorded as voting in favor of second reading of the Bill as they were out of the chamber meeting with the Governor regarding the Savannah River Site.
H. 4347 (Word version) -- Reps. Bannister, Cobb-Hunter, McCoy, Allison, Whipper and Gilliard: A BILL TO AMEND THE CODE OF LAWS OF SOUTH CAROLINA, 1976, SO AS TO ENACT THE "SOUTH CAROLINA CHILDREN'S ADVOCACY MEDICAL RESPONSE SYSTEM ACT" BY ADDING ARTICLE 4 TO CHAPTER 11, TITLE 63 SO AS TO CREATE THE SOUTH CAROLINA CHILDREN'S ADVOCACY MEDICAL RESPONSE SYSTEM, A PROGRAM TO PROVIDE COORDINATION AND MEDICAL SERVICE RESOURCES STATEWIDE TO AGENCIES AND ENTITIES THAT RESPOND TO VICTIMS OF CHILD ABUSE AND NEGLECT, AND TO PROVIDE FOR THE DUTIES AND RESPONSIBILITIES OF THE PROGRAM; AND TO AMEND SECTION 63-11-310, RELATING TO RESPONSIBILITIES OF CHILDREN'S ADVOCACY CENTERS, SO AS TO REQUIRE THESE CENTERS TO COMPLY WITH REQUIREMENTS OF THE SOUTH CAROLINA CHILDREN'S MEDICAL RESPONSE SYSTEM AND OTHERWISE COORDINATE WITH THE PROGRAM.
The Senate proceeded to a consideration of the Bill, the question being the adoption of the amendment proposed by the Committee on Judiciary.
The Committee on Judiciary proposed the following amendment (JUD4347.001), which was adopted:
Amend the bill, as and if amended, page 1, by striking lines 28 through 38.
Renumber sections to conform.
Amend title to conform.
Senator MASSEY explained the committee amendment.
The question then was second reading of the Bill.
The "ayes" and "nays" were demanded and taken, resulting as follows:
Ayes 35; Nays 0
AYES
Alexander Bennett Bright
Bryant Campbell Cleary
Corbin Courson Cromer
Davis Grooms Hayes
Hembree Johnson Kimpson
Leatherman Lourie Malloy
Martin, Larry Martin, Shane Massey
Matthews McElveen McGill
Nicholson Peeler Scott
Setzler Shealy Sheheen
Thurmond Turner Verdin
Williams Young
Total--35
NAYS
Total--0
There being no further amendments, the Bill was read the second time, passed and ordered to a third reading.
S. 841 (Word version) -- Senator Cleary: A BILL TO AMEND ARTICLE 1, CHAPTER 13, TITLE 63, SOUTH CAROLINA CODE OF LAWS, 1976, RELATING TO THE REGULATION OF CHILDCARE FACILITIES, BY ADDING SECTION 63-13-185, SO AS TO PROHIBIT THE ADMINISTRATION OF MEDICATION TO A CHILD BY AN EMPLOYEE OR VOLUNTEER OF A CHILDCARE FACILITY WITHOUT PARENTAL PERMISSION, AND TO INCLUDE EXCEPTIONS IN CIRCUMSTANCES OF EMERGENCIES, AND TO PROVIDE PENALTIES.
The Senate proceeded to a consideration of the Bill, the question being the adoption of the amendment proposed by the Committee on Judiciary.
The Committee on Judiciary proposed the following amendment (JUD0841.001), which was adopted:
Amend the bill, as and if amended, page 2, by striking line 15, in Section 63-13-185(E), as contained in SECTION 1, and inserting therein the following:
/ guilty of a misdemeanor and, upon conviction, may be imprisoned /
Renumber sections to conform.
Amend title to conform.
Senator MASSEY explained the committee amendment.
The question then was second reading of the Bill.
The "ayes" and "nays" were demanded and taken, resulting as follows:
Ayes 37; Nays 0
AYES
Alexander Bennett Bright
Bryant Campbell Cleary
Coleman Corbin Courson
Cromer Davis Fair
Gregory Grooms Hayes
Johnson Kimpson Leatherman
Lourie Malloy Martin, Larry
Martin, Shane Massey McElveen
McGill Nicholson O'Dell
Peeler Scott Setzler
Shealy Sheheen Thurmond
Turner Verdin Williams
Young
Total--37
NAYS
Total--0
There being no further amendments, the Bill was read the second time, passed and ordered to a third reading.
S. 882 (Word version) -- Senator Sheheen: A BILL TO AMEND SECTION 41-27-210 OF THE 1976 CODE, RELATING TO THE DEFINITION OF EMPLOYMENT; TO PROVIDE THAT INDIVIDUALS THAT TRANSPORT VEHICLES FOR AUTOMOBILE DEALERS UNDER CERTAIN CIRCUMSTANCES ARE EXCLUDED FROM THE DEFINITION; AND TO PROVIDE FOR THOSE CIRCUMSTANCES.
The Senate proceeded to a consideration of the Bill, the question being the adoption of the amendment proposed by the Committee on Labor, Commerce and Industry.
The Committee on Labor, Commerce and Industry proposed the following amendment (882R005.TCA), which was adopted:
Amend the bill, as and if amended, by striking all after the enacting words and inserting:
/ SECTION 1. Section 41-27-260 of the 1976 Code is amended by adding an appropriately numbered new item to read:
"( ) an individual performing a service for an automobile dealer related to the transportation of individual vehicles to purchasers or sellers of vehicles, including, but not limited to, an automobile auction, when the contract of service contemplates that the service is to be performed personally by the individual, the individual does not own the vehicle used in connection with the performance of the service, and the service is in the nature of a single transaction with no guarantee of a continuing relationship with the automobile dealer for whom the service is performed."
SECTION 2. This act takes effect upon approval by the Governor. /
Renumber sections to conform.
Amend title to conform.
Senator BRYANT explained the committee amendment.
The question then was second reading of the Bill.
The "ayes" and "nays" were demanded and taken, resulting as follows:
Ayes 37; Nays 0
AYES
Alexander Allen Bennett
Bright Bryant Campbell
Cleary Coleman Corbin
Courson Cromer Davis
Fair Gregory Grooms
Hayes Hembree Johnson
Kimpson Leatherman Lourie
Martin, Larry Martin, Shane Massey
McElveen McGill Nicholson
Peeler Scott Setzler
Shealy Sheheen Thurmond
Turner Verdin Williams
Young
Total--37
NAYS
Total--0
There being no further amendments, the Bill was read the second time, passed and ordered to a third reading.
S. 1065 (Word version) -- Senator Hayes: A BILL TO AMEND THE CODE OF LAWS OF SOUTH CAROLINA, 1976, BY ADDING ARTICLE 5 TO CHAPTER 43, TITLE 38 SO AS TO PROVIDE FOR THE LIMITED LICENSING OF SELF-STORAGE FACILITIES TO SELL OR OFFER INSURANCE.
The Senate proceeded to a consideration of the Bill, the question being the adoption of the amendment proposed by the Committee on Banking and Insurance.
The Committee on Banking and Insurance proposed the following amendment (AGM\1065C002.AGM.AB14), which was adopted:
Amend the bill, as and if amended, by deleting all after the enacting words and inserting:
/ SECTION 1. Chapter 43, Title 38 of the 1976 Code is amended by adding:
"Article 5
Limited Licensing of Self-Service Storage Facilities to Sell or Offer Insurance
(2) 'Limited license' means the authority of a person authorized to sell certain insurance pursuant to the provisions of this article.
(3) 'Rental agreement' means a written agreement setting forth the terms and conditions governing the use of a storage space provided by a self-service storage facility for rental or lease.
(4) 'Owner' means the owner of a self-service storage facility or his agent.
(5) 'Occupant' means a person or his lessee, successor, or assignee entitled to the use of the storage space at a self-storage facility under a rental agreement to the exclusion of others.
(6) 'Self-service storage facility' means real property designed and used for the sole purpose of renting or leasing individual storage space to occupants given access to this storage space for the sole purpose of storing and removing personal property.
(7) 'Rental period' means the term of a rental agreement.
Section 38-43-620. The director or his designee may issue a limited license to an owner who has complied with the requirements of this article.
Section 38-43-630. (A) Before issuing a limited license, an application for a limited license must be filed with the director, signed by an officer of the applicant, on a form prescribed by the department. An applicant for a limited license must be approved and vouched for by an official or licensed representative of the insurer for which the applicant proposes to act pursuant to Section 38-43-40 and Section 38-43-50. An application must be accompanied by a forty dollar fee. A limited license must be renewed biennially before May first of odd numbered years on a renewal application form provided by the department, and this form must be accompanied by a forty dollar renewal fee. The department shall cancel a license that is not renewed as required by this section. The licensee may reinstate a license within six months after the renewal deadline by paying the forty dollar renewal fee and a forty dollar reinstatement fee. A limited license fee is not refundable.
(B) A limited license holder must not advertise, represent, or otherwise hold itself or its employee out as a licensed insurer, insurance agent, or insurance broker.
Section 38-43-640. (A) A licensee must be the owner of a self-service rental facility or his employee or agent.
(B) A licensee only may sell or offer to sell insurance in connection with, and incidental to, the rental of a self-storage space in the owner's facility. This insurance only may provide coverage for:
(1) casualty loss of the property contained in the self-storage space;
(2) liability insurance for personal injuries, excluding injuries compensable by workers' compensation, arising on the premises of the individual self-storage space; or
(3) both.
Section 38-43-650. (A) Prior to issuing a policy under the provisions of this chapter, a licensee shall provide a written document that:
(1) summarizes clearly and correctly the material terms of coverage offered to an occupant, including the identity of the insurer;
(2) discloses that the coverage offered by the self-service storage facility may provide a duplication of coverage already provided by a homeowners' insurance policy or other source of coverage in effect for the occupant;
(3) describes the process for filing a claim if the occupant elects to purchase coverage and in the event of a claim; and
(4) states that the charges for coverage are itemized and ancillary to the rental agreement.
(B) If the rental agreement requires the occupant to provide insurance of the type described in Section 38-43-640(B), this requirement may be satisfied if the occupant:
(1) purchases this coverage from a licensee; or
(2) provides evidence of this coverage from another source.
Section 38-43-660. (A) The employee or agent of an owner who is a licensee may act individually on behalf, and under the supervision of, the owner-licensee with respect to providing coverage for which the licensee is authorized to provide, but only if the owner instructs the employee or agent about the kinds of insurance sold pursuant to the owner's license.
(B) The provisions of this chapter do not prohibit:
(1) the payment or receipt of a commission for the sale of insurance that the licensee is authorized to sell; and
(2) the payment of a bonus, incentive payment, or compensation by a licensee to his employee or agent; provided, however, that these payments may not be made based on the completion of a sale of insurance coverage.
Section 38-43-670. Notwithstanding another provision of this chapter, a regulation promulgated by the department, or an order issued by the director, a licensee, his employee, and agent must not be required to:
(1) act as a fiduciary of money received from the sale of insurance authorized to be sold under the provisions of this chapter; or
(2) hold this money in a separate trust account if the insurer represented by the license holder provides written consent, signed by an officer of the insurer, that a premium is not required to be segregated from money received by the license holder because of the consumer transaction associated with the coverage.
Section 38-43-680. The director may, after notice and opportunity for a hearing, respond to a violation of a provision of this chapter under the provisions of Section 38-2-10 by:
(1) revoking or suspending a limited license; or
(2) imposing other penalties, including suspending the transaction of insurance at a specific rental location where a violation of this chapter occurred, as the director considers necessary or convenient to carry out the provisions of this chapter."
SECTION 2. This act takes effect upon approval by the Governor. /
Renumber sections to conform.
Amend title to conform.
Senator CROMER explained the committee amendment.
The question then was second reading of the Bill.
The "ayes" and "nays" were demanded and taken, resulting as follows:
Ayes 37; Nays 0
AYES
Alexander Bennett Bright
Bryant Campbell Cleary
Coleman Corbin Courson
Cromer Davis Fair
Gregory Grooms Hayes
Hembree Johnson Kimpson
Lourie Malloy Martin, Larry
Martin, Shane Massey McElveen
McGill Nicholson O'Dell
Peeler Scott Setzler
Shealy Sheheen Thurmond
Turner Verdin Williams
Young
Total--37
NAYS
Total--0
There being no further amendments, the Bill was read the second time, passed and ordered to a third reading.
Senator SHANE MARTIN asked unanimous consent to allow Senator CLEARY to make an expression of personal interest.
There was no objection.
H. 3421--Expression of Personal Interest
Senator CLEARY rose for an Expression of Personal Interest.
S. 1097 (Word version) -- Senator Alexander: A CONCURRENT RESOLUTION TO AFFIRM THE DEDICATION OF THE GENERAL ASSEMBLY TO THE FUTURE SUCCESS OF SOUTH CAROLINA'S YOUNG PEOPLE AND TO THE PREVENTION OF CHILD ABUSE AND NEGLECT AND TO DECLARE THE MONTH OF APRIL AS "CHILD ABUSE PREVENTION MONTH" IN THE STATE OF SOUTH CAROLINA.
The Concurrent Resolution was adopted, ordered sent to the House.
H. 4748 (Word version) -- Reps. Owens, Alexander, Allison, Anderson, Anthony, Atwater, Bales, Ballentine, Bannister, Barfield, Bedingfield, Bernstein, Bingham, Bowen, Bowers, Branham, Brannon, G.A. Brown, R.L. Brown, Burns, Chumley, Clemmons, Clyburn, Cobb-Hunter, Cole, H.A. Crawford, K.R. Crawford, Crosby, Daning, Delleney, Dillard, Douglas, Edge, Erickson, Felder, Finlay, Forrester, Funderburk, Gagnon, Gambrell, George, Gilliard, Goldfinch, Govan, Hamilton, Hardee, Hardwick, Harrell, Hart, Hayes, Henderson, Herbkersman, Hiott, Hixon, Hodges, Horne, Hosey, Howard, Huggins, Jefferson, Kennedy, King, Knight, Limehouse, Loftis, Long, Lowe, Lucas, Mack, McCoy, McEachern, M.S. McLeod, W.J. McLeod, Merrill, Mitchell, D.C. Moss, V.S. Moss, Munnerlyn, Murphy, Nanney, Neal, Newton, Norman, Norrell, R.L. Ott, Parks, Patrick, Pitts, Pope, Putnam, Quinn, Ridgeway, Riley, Rivers, Robinson-Simpson, Rutherford, Ryhal, Sabb, Sandifer, Sellers, Simrill, Skelton, G.M. Smith, G.R. Smith, J.E. Smith, J.R. Smith, Sottile, Southard, Spires, Stavrinakis, Stringer, Tallon, Taylor, Thayer, Toole, Vick, Weeks, Wells, Whipper, White, Whitmire, Williams, Willis and Wood: A CONCURRENT RESOLUTION TO RECOGNIZE AND EXPRESS DEEP APPRECIATION TO THE SOUTH CAROLINA TECHNICAL COLLEGE SYSTEM FOR ITS OUTSTANDING CONTRIBUTIONS IN EDUCATING AND TRAINING OUR STATE'S WORKFORCE AND TO DECLARE MARCH 25, 2014, AS SOUTH CAROLINA TECHNICAL COLLEGE SYSTEM DAY.
The Concurrent Resolution was adopted, ordered returned to the House.
H. 4766 (Word version) -- Reps. J.E. Smith, Alexander, Allison, Anderson, Anthony, Atwater, Bales, Ballentine, Bannister, Barfield, Bedingfield, Bernstein, Bingham, Bowen, Bowers, Branham, Brannon, G.A. Brown, R.L. Brown, Burns, Chumley, Clemmons, Clyburn, Cobb-Hunter, Cole, H.A. Crawford, K.R. Crawford, Crosby, Daning, Delleney, Dillard, Douglas, Edge, Erickson, Felder, Finlay, Forrester, Funderburk, Gagnon, Gambrell, George, Gilliard, Goldfinch, Govan, Hamilton, Hardee, Hardwick, Harrell, Hart, Hayes, Henderson, Herbkersman, Hiott, Hixon, Hodges, Horne, Hosey, Howard, Huggins, Jefferson, Kennedy, King, Knight, Limehouse, Loftis, Long, Lowe, Lucas, Mack, McCoy, McEachern, M.S. McLeod, W.J. McLeod, Merrill, Mitchell, D.C. Moss, V.S. Moss, Munnerlyn, Murphy, Nanney, Neal, Newton, Norman, Norrell, R.L. Ott, Owens, Parks, Patrick, Pitts, Pope, Putnam, Quinn, Ridgeway, Riley, Rivers, Robinson-Simpson, Rutherford, Ryhal, Sabb, Sandifer, Sellers, Simrill, Skelton, G.M. Smith, G.R. Smith, J.R. Smith, Sottile, Southard, Spires, Stavrinakis, Stringer, Tallon, Taylor, Thayer, Toole, Vick, Weeks, Wells, Whipper, White, Whitmire, Williams, Willis and Wood: A CONCURRENT RESOLUTION TO DECLARE WEDNESDAY, MARCH 19, 2014, "NATIONAL GUARD DAY" IN SOUTH CAROLINA AND TO RECOGNIZE AND HONOR THE MANY SACRIFICES AND VALUABLE CONTRIBUTIONS THE SOUTH CAROLINA NATIONAL GUARD MAKES TO PROTECT THE FREEDOM, DEMOCRACY, AND SECURITY OF OUR STATE AND NATION.
The Concurrent Resolution was adopted, ordered returned to the House.
CARRIED OVER
S. 1033 (Word version) -- Senators Campbell, Leatherman, Setzler, O'Dell and Alexander: A BILL TO AMEND CHAPTER 2, TITLE 12 OF THE 1976 CODE, RELATING TO TAXATION, BY ADDING SECTION 12-2-110, TO PROVIDE AN OUT-OF-STATE BUSINESS THAT CONDUCTS OPERATIONS WITHIN THIS STATE FOR THE PURPOSES OF PERFORMING WORK OR SERVICES RELATED TO A DECLARED STATE DISASTER OR EMERGENCY DURING A DISASTER PERIOD MUST NOT BE CONSIDERED TO HAVE ESTABLISHED A LEVEL OF PRESENCE THAT WOULD REQUIRE THAT BUSINESS TO REGISTER, FILE, AND REMIT STATE OR LOCAL TAXES OR THAT WOULD REQUIRE THAT BUSINESS OR ITS OUT-OF-STATE EMPLOYEES TO BE SUBJECT TO ANY STATE LICENSING OR REGISTRATION REQUIREMENTS OR ANY COMBINATION OF THESE ACTIONS.
On motion of Senator MALLOY, the Bill was carried over.
S. 511 (Word version) -- Senator Campsen: A BILL TO AMEND SECTION 12-43-220, AS AMENDED, CODE OF LAWS OF SOUTH CAROLINA, 1976, RELATING TO THE FOUR PERCENT SPECIAL ASSESSMENT RATIO, SO AS TO PROVIDE THAT AN ELIGIBILITY PROVISION REQUIRING A CERTAIN OWNERSHIP PERCENTAGE DOES NOT APPLY IF THE PROPERTY IS HELD BY A TRUST, FAMILY LIMITED PARTNERSHIP, OR LIMITED LIABILITY COMPANY UNDER CERTAIN SITUATIONS.
On motion of Senator MALLOY, the Bill was carried over.
S. 862 (Word version) -- Senators Shealy and Turner: A BILL TO AMEND SECTION 40-59-260 OF THE 1976 CODE, RELATING TO THE EXCEPTION FOR PROJECTS BY A PROPERTY OWNER FOR PERSONAL USE, TO PROVIDE THAT AN OWNER OF RESIDENTIAL PROPERTY WHO IMPROVES THE PROPERTY OR WHO BUILDS OR IMPROVES THE STRUCTURES OR APPURTENANCES ON THE PROPERTY AT A COST OF MORE THAN TWO THOUSAND FIVE HUNDRED DOLLARS SHALL NOT WITHIN TWO YEARS AFTER COMPLETION OR ISSUANCE OF A CERTIFICATE OFFER THE STRUCTURE FOR SALE OR RENT, AND CONSTRUCTION OR IMPROVEMENTS TO THE STRUCTURE, GROUP OF STRUCTURES, OR APPURTENANCES THAT COST THE OWNER-BUILDER LESS THAN TWO THOUSAND FIVE HUNDRED DOLLARS ARE NOT EVIDENCE OF "SALE" OR "RENT" FOR THE PURPOSES OF THIS SECTION.
On motion of Senator SHEALY, the Bill was carried over.
S. 343 (Word version) -- Senator Hayes: A BILL TO AMEND CHAPTER 7, TITLE 36, CODE OF LAWS OF SOUTH CAROLINA, 1976, RELATING TO ARTICLE 7 OF THE UNIFORM COMMERCIAL CODE, SO AS TO REVISE THE CHAPTER IN ITS ENTIRETY IN ORDER TO PROVIDE FOR THE USE OF ELECTRONIC DOCUMENTS OF TITLE AND TO MAKE CONFORMING CHANGES.
On motion of Senator BRIGHT, the Bill was carried over.
S. 1026 (Word version) -- Senator Alexander: A BILL TO AMEND SECTION 29-5-440, CODE OF LAWS OF SOUTH CAROLINA, 1976, RELATING TO SUITS ON CONTRACTOR PAYMENT BONDS, SO AS TO PROVIDE THAT CERTAIN WRITTEN NOTICE REQUIRED OF A REMOTE CLAIMANT MUST BE SENT BY CERTIFIED OR REGISTERED MAIL, AND MUST GENERALLY CONFORM WITH STATUTORY LIMITS ON THE AGGREGATE AMOUNT OF LIENS FILED BY A SUB-SUBCONTRACTOR OR SUPPLIER; TO PROVIDE ANY PAYMENT BOND SURETY FOR THE BONDED CONTRACTOR SHALL HAVE THE SAME RIGHTS AND DEFENSES OF THE BONDED CONTRACTOR; TO MAKE THE LANGUAGE APPLICABLE TO ANY PAYMENT BOND WHETHER PRIVATE, COMMON LAW, PUBLIC, OR STATUTORY IN NATURE, WHEN THE BONDS ARE NOT OTHERWISE REQUIRED OR GOVERNED BY STATUTE; AND TO PROVIDE NECESSARY DEFINITIONS.
Senator CROMER explained the Bill.
On motion of Senator MALLOY, the Bill was carried over.
THE CALL OF THE UNCONTESTED CALENDAR HAVING BEEN COMPLETED, THE SENATE PROCEEDED TO THE MOTION PERIOD.
At 1:12 P.M., on motion of Senator COURSON, the Senate agreed to adjourn.
LOCAL APPOINTMENTS
Confirmations
Having received a favorable report from the Senate, the following appointments were confirmed in open session:
Reappointment, Horry County Board of Voter Registration, with the term to commence March 15, 2014, and to expire March 15, 2016
J. Michael Frazier, 731 Bucksport Rd., Conway, SC 29527
Reappointment, Horry County Board of Voter Registration, with the term to commence March 15, 2014, and to expire March 15, 2016
Maurice Jones, 4525 Canal Street, Loris, SC 29569
Initial Appointment, Abbeville County Magistrate, with the term to commence April 30, 2010, and to expire April 30, 2014
Philip D. Ray, 527 Noble Dr., Abbeville, SC 29620 VICE George T. Fergeson
Reappointment, Abbeville County Magistrate, with the term to commence April 30, 2014, and to expire April 30, 2018
Philip D. Ray, 527 Noble Dr., Abbeville, SC 29620
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https://lavelle.chem.ucla.edu/forum/search.php?author_id=11207&sr=posts
|
## Search found 51 matches
Sun Mar 11, 2018 3:21 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Too Slow to Include in Mechanism
Replies: 1
Views: 94
### Re: Reaction Too Slow to Include in Mechanism
I think the problem will usually just let you know!
Sun Mar 11, 2018 3:20 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate-determining slowest step
Replies: 5
Views: 209
### Re: Rate-determining slowest step
I think the problem will usually tell you which is slower on the side in parentheses or something. If not it will give you the experimental rate law and you can tell from which reactants are included in the rate law which step is the slow step
Sun Mar 11, 2018 3:19 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Elementary Step
Replies: 4
Views: 122
### Re: Elementary Step
I like to think of elementary steps as straight forward steps so what you see is what you get. While the overall reaction may contain intermediates that aren’t included, the elementary step contains the exact reactants and products and so we can derive the rate law for the elementary step right from...
Mon Mar 05, 2018 10:53 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Unique rates
Replies: 4
Views: 215
### Re: Unique rates
Dr. Lavelle just mentioned unique rates last week. Whereas average rate is the change in concentration over the change in time, and is different for each product and reactant, unique rate is the same for every product and reactant in that specific, or "unique", reaction. To find unique rat...
Mon Mar 05, 2018 10:48 pm
Forum: General Rate Laws
Topic: 15.3 Rate Laws Depending on concentrations of products
Replies: 3
Views: 142
### Re: 15.3 Rate Laws Depending on concentrations of products
In the homework, there were a couple problems on rate law and proposing mechanisms. Only one of them had an elementary step that had a significant reverse reaction, and it was given to you in the problem that that was the case, so I don't think you need to worry about it too much!
Mon Mar 05, 2018 10:44 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7582
Views: 1015154
### Re: Post All Chemistry Jokes Here
What did atom A say to the atom B who was telling this joke?
You're such a Boron
Mon Feb 26, 2018 6:21 pm
Forum: First Order Reactions
Topic: Equation in the Book vs. in Lecture
Replies: 2
Views: 127
### Re: Equation in the Book vs. in Lecture
They include both in the book. It just depends on the problem and what you are solving for. Like, if you are solving for time t or k, the equation with ln would be better. If you are solving for concentration, the exponential form would be easier to use
Mon Feb 26, 2018 6:18 pm
Forum: Second Order Reactions
Topic: 15.19
Replies: 2
Views: 133
### Re: 15.19
You divide out the number. So [B] goes from 1.25 to 3.02 which means it increased by a factor of 2.416. The rate goes from 8.7 to 50.8, so it increased by a factor of 5.839. Since everything else in the rate law is the same, you can set the factor by which [B] increased ^c equals the factor by which...
Mon Feb 26, 2018 6:13 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Units for Concentration
Replies: 4
Views: 177
### Re: Units for Concentration
I don't think it matters, you should just know which ones u were working with to match the units!
Sun Feb 18, 2018 10:26 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Determining Q when only one element is involved
Replies: 1
Views: 82
### Re: Determining Q when only one element is involved
You would not cancel out the aqueous Ag+ and treat each molarity of Ag separately. Therefore, for Q, you would have Ag+ of .005M on top and .15M on the bottom.
Sun Feb 18, 2018 10:23 pm
Forum: Balancing Redox Reactions
Topic: HW 14.11 d
Replies: 1
Views: 120
### Re: HW 14.11 d
I'm not sure if this is what you're asking, but the OH- is just included in the half-reaction in the table at the back of the book already. They just took the equation straight as it was out of the appendix
Sun Feb 18, 2018 10:21 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Example 14.8 (pg 586)
Replies: 1
Views: 93
### Re: Example 14.8 (pg 586)
It seems like they did switch it. Or rather, you are mixing up the two methods. One method is to reverse the sign for the oxidation half reaction and then add it to the reduction half reaction. The other is to keep the signs as they are and subtract the potential of the oxidation half reaction from ...
Sun Feb 11, 2018 4:40 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: signs
Replies: 3
Views: 135
### Re: signs
I don't think you ever actually have to put +. It's probably just for emphasis/clarity
Sun Feb 11, 2018 4:38 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: equilibrium
Replies: 3
Views: 161
### Re: equilibrium
at equilibrium Ecell should equal 0 V
Sun Feb 11, 2018 4:37 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Orientations for Boltzmann Formula
Replies: 1
Views: 114
### Re: Orientations for Boltzmann Formula
I don't think we would be given anything too crazy. Just like CO would have 2 positions and N2would only have 1. I think they would be easy enough that we could visualize it or draw it out which is what i did for one of the homework problems. There was also a hw problem that told you the number of p...
Sun Feb 04, 2018 6:46 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Example 9.5 (page 325)
Replies: 2
Views: 108
### Re: Example 9.5 (page 325)
tl;dr LOL
BaSically you do the change in volume first and then do the change in temperature so when you’re calculating the temperature, the volume has already changed and is now constant.
Don’t use pressure bc it is not specified what is happening with that so it is better to avoid dealing with it
Sun Feb 04, 2018 6:42 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: conceptual question about change in entropy due to both temp and vol [ENDORSED]
Replies: 3
Views: 168
### Re: conceptual question about change in entropy due to both temp and vol[ENDORSED]
We are assuming, by using the two step process, that first the volume increases and then the temperature increases(or decreases whatever the problem says) so when the temperature is changing, the volume has already changed and is now constant
Sun Feb 04, 2018 6:40 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: ΔS of vaporization
Replies: 2
Views: 120
### Re: ΔS of vaporization
They explain this in the book. I’m not sure but off the top of my head I think the reason for this is that gas molecules of different substances behave in the same way so when liquids become gases they kind of change in the same way (so entropy change is the same). The only reason the change in entr...
Mon Jan 29, 2018 10:49 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: 9.15a [ENDORSED]
Replies: 2
Views: 95
### Re: 9.15a[ENDORSED]
delta H fus is 6.01 for melting so for freezing you would have to reverse the sign and make it -6.01 kJ/mol!
Mon Jan 29, 2018 10:46 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Temperature units for Entropy [ENDORSED]
Replies: 2
Views: 132
### Re: Temperature units for Entropy[ENDORSED]
It does make a difference since the temperatures are being divided you would get different answers for Kelvins vs Celsius. I think you should be using Kelvins but Im not sure why. might be in the derivation of the formula!
Mon Jan 29, 2018 10:42 am
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Entropy in Relation to Temp [ENDORSED]
Replies: 1
Views: 88
### Re: Entropy in Relation to Temp[ENDORSED]
The equation is actually deltaS = q/T. When temperature is lower, then deltaS will be more. It makes sense if you think about it, although I'm not sure why. If we have one system that is at a lower temperature and one that is at a higher temperature but we input the same amount of heat, the heat wil...
Sun Jan 21, 2018 1:32 pm
Forum: Phase Changes & Related Calculations
Topic: Calculating the Initial Temperature Of An Object
Replies: 3
Views: 272
### Re: Calculating the Initial Temperature Of An Object
You would find the q of the water using the change in temperature and q=mC(deltaT). Then set the negative that equal to the amount of heat the copper lost (they should give you the specific heat capacity of copper) and solve for delta T. Use delta T to then find initial temperature. (the final tempe...
Sun Jan 21, 2018 1:29 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: 8.57
Replies: 1
Views: 86
### Re: 8.57
I think you're talking about Hess's Law right? The equations would have to be given, but it some cases, the question just says "the combustion of" and so you would have to write the equation yourself with your knowledge of combustion (i.e. compound + O2--> CO2 + H2O
Sun Jan 21, 2018 1:26 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Wed 01/17 Lecture
Replies: 1
Views: 101
### Re: Wed 01/17 Lecture
The density of water is 1g/ml. I think what you're referring to is that Lavelle said to assume the density of the solution is like water (~1 g/mL) because it is dilute enough to do so. I may be wrong, but I think the importance of knowing the density is just so we can covert from volume (mL) to mass...
Tue Jan 16, 2018 4:17 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Finding change in enthalpy of a rxn
Replies: 3
Views: 170
### Re: Finding change in enthalpy of a rxn
For problems in the textbook I believe they are in a table in the appendix of the book
Tue Jan 16, 2018 4:12 pm
Forum: Phase Changes & Related Calculations
Topic: question 8.41
Replies: 5
Views: 260
### Re: question 8.41
You might also be using the wrong C for the ice. It should be 4.184, the liquid form, because the ice has melted into liquid before it rises in temperature. (I did this and couldn't figure out the problem for a while lol but you might have done what the above person stated, I don't remember the answ...
Tue Jan 16, 2018 4:09 pm
Forum: Phase Changes & Related Calculations
Topic: Homework Problem 8.41
Replies: 1
Views: 132
### Re: Homework Problem 8.41
To start this problem, realize that the heat the ice cube gains is equal to the heat the surrounding water loses. First, take into account the energy needed to melt the ice (deltaH fusion=6.01kJ/mol) and add it to the amount of energy needed to raise the ice cube x degrees (using q=mCdeltaT). Then s...
Thu Jan 11, 2018 4:28 pm
Forum: Phase Changes & Related Calculations
Topic: ∆Hsub= ∆Hfus+ ∆Hvap
Replies: 4
Views: 414
### Re: ∆Hsub= ∆Hfus+ ∆Hvap
enthalpy is a state function which makes it additive. Sublimation is a solid going to a vapor and fusion is a solid to a liquid and vaporization is a liquid to a vapor. So if you take out the middle step, it becomes solid to vapor. Basically, the same amount of energy goes into converting a solid di...
Thu Jan 11, 2018 4:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Why is fusion another name for melting?
Replies: 4
Views: 214
### Re: Why is fusion another name for melting?
Abel Thomas 2C wrote:It may have to do with the fact the etymology of the word fusion comes from the Latin "fundere" which means "melting together".
I think this is correct. That's what my TA said during discussion
Thu Jan 11, 2018 4:18 pm
Forum: Phase Changes & Related Calculations
Topic: Hess Law [ENDORSED]
Replies: 5
Views: 265
### Re: Hess Law[ENDORSED]
yup basically multiply by (-)
Sun Dec 03, 2017 11:52 pm
Forum: Sigma & Pi Bonds
Topic: Pi bonds
Replies: 3
Views: 303
### Re: Pi bonds
pretty much! the leftover unhybridized orbitals just overlap as pi bonds
Sun Dec 03, 2017 11:50 pm
Forum: Resonance Structures
Topic: Naming coordination compounds [ENDORSED]
Replies: 3
Views: 291
### Re: Naming coordination compounds[ENDORSED]
Yes! One of them is just an updated way. I remember Lavelle saying he will accept either :)
Sun Nov 26, 2017 10:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 11.45 Equilibrium in terms of stability
Replies: 1
Views: 140
### Re: 11.45 Equilibrium in terms of stability
In this question if you complete steps a and b you will see that the value of x for Cl2 is less than that for F2. That means less Cl2 was converted to Cl than F2 was converted to F--hence, Cl2 is more stable than F. There may be more underlying the answer but that's what makes sense to me :)
Sun Nov 26, 2017 10:36 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Aqueous and Gaseous Phases
Replies: 3
Views: 170
### Re: Aqueous and Gaseous Phases
It depends what is given in the problem. If the concentrations of all the reactants, whether gaseous or aqueous, are given, then it is safe to use Kc. If the pressure is given for the gaseous phases, then you would need to use pv=nrt to find the concentrations by first finding n (the number of moles...
Tue Nov 21, 2017 8:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW question 11.7
Replies: 2
Views: 215
### Re: HW question 11.7
Hey! Sorry I don't have an answer to your question, but I was wondering if you could walk me through how you got the 0.17 number. I was a little confused about that. Thanks! Hey yeah I can tell you how the solutions manual did it! The chemical equation for this problem is X2->2X so K=(p of products...
Mon Nov 20, 2017 10:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Reaction arrows
Replies: 3
Views: 203
### Re: Reaction arrows
The double arrows are used to express the state of dynamic equilibrium--both reactions are occurring at the same time at stable rates so that the concentrations/pressures of each do not change. From what I remember from high school I believe the reverse reaction is not always happening (if there are...
Mon Nov 20, 2017 10:33 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW question 11.7
Replies: 2
Views: 215
### HW question 11.7
So I was doing the homework and for 11.7 part c, the value of K turned out to be .17. However, at equilibrium the reactant had become more product (6 out of 11 X2 decomposed). Shouldn't K be larger than 1 then? Also, Avogadro's law states that, "equal volumes of all gases, at the same temperatu...
Mon Nov 13, 2017 3:43 pm
Forum: Lewis Structures
Topic: Midterm Question CH3SH
Replies: 5
Views: 303
### Re: Midterm Question CH3SH
Yup that's what I got too! It works out very neatly with every atom having a formal charge of 0 :)
Mon Nov 13, 2017 3:36 pm
Forum: Bond Lengths & Energies
Topic: Bond Length
Replies: 8
Views: 1051
### Re: Bond Length
All three of the examples come from an H bonded with a halogen so the structure of the bond is pretty much the same--H single bonded to the halogen. The difference in bond length comes from the size of the atom. Bond length is the measure of the center of one atom to the other, and since I has the b...
Mon Nov 06, 2017 11:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Which one do I draw?
Replies: 5
Views: 333
### Re: Which one do I draw?
I think Professor Lavelle said we would pretty much never have to draw the 3D vsepr model. For vsepr, we will probably only be asked to name the structure, bond angles, and to give the vsepr formula, which would be in the form AXE
Mon Nov 06, 2017 11:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Xenon Tetrafluoride?
Replies: 4
Views: 414
### Re: Xenon Tetrafluoride?
Usually noble gases would not form any bonds but since xenon is such a heavy noble gas with valence electrons so far away from the nucleus and experiencing very little attraction that it can be forced to make bonds with very electronegative elements such as fluorine. As stated above, you probably d...
Tue Oct 31, 2017 12:12 am
Forum: Octet Exceptions
Topic: Octet Exceptions
Replies: 3
Views: 379
### Re: Octet Exceptions
I think you can figure it out using formal charge and electronegativity. For instance, in SO4 2- the S has a formal charge of 0 when there are 2 double bonded O's which is more favorable than having only one double bonded O. However, it cannot have 3 double bonded O's because then it would have a FC...
Tue Oct 31, 2017 12:09 am
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 10
Views: 407
### Re: Lewis Structures
You probably won't have to worry I think they usually will ask for it
Fri Oct 27, 2017 1:19 am
Forum: Quantum Numbers and The H-Atom
Topic: P-Orbitals (x,y,z) [ENDORSED]
Replies: 3
Views: 1791
### Re: P-Orbitals (x,y,z)[ENDORSED]
Same with above. In my lecture, I remember Professor Lavelle saying that we only use Px Py Pz when we want to accentuate that the electrons are occupying separate orbitals. Other than that, it is fine to just use p1 p2 p3
Fri Oct 27, 2017 1:17 am
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 4
Views: 528
### Re: Magnetic Quantum Number
Catherine Yang 3G wrote:
Do the ml values correspond to a specific orientation? Like do px orbitals correspond to ml=-1 for example? Thanks!
Yes I'm pretty sure that the ml values correspond to a specific orientation, but I'm also pretty sure that we won't need to know the content that specifically :)
Tue Oct 17, 2017 9:11 pm
Forum: Properties of Electrons
Topic: Energy Level Change
Replies: 5
Views: 304
### Re: Energy Level Change
To add, is there any specific reason an electron wouldn't automatically just jump back to level one? is it random? I went to office hours and Lavelle answered a similar question someone had. The question was "why do some electrons go from n=4 to n=2 while others go straight down to n=1?" ...
Tue Oct 17, 2017 9:06 pm
Forum: Properties of Light
Topic: Color of visible light
Replies: 11
Views: 574
### Re: Color of visible light
I have seen a homework question that asked for the color of the visible light. However, I don't think that Professor Lavelle would expect us to know it aside from that violets and blues have the shorter wavelengths and reds and oranges the longer. In fact, the spectrum is much like a rainbow in the ...
Thu Oct 12, 2017 8:46 pm
Forum: Properties of Light
Topic: Prefix Conversion
Replies: 12
Views: 545
### Re: Prefix Conversion
I would convert in the beginning or right when you are doing the problem. It would be best to have the same units so that they can properly cancel out. Doing so, you will be seeing that you end up with the right units in your answer.
Thu Oct 12, 2017 8:38 pm
Forum: Ideal Gases
Topic: Reading the textbook [ENDORSED]
Replies: 127
Views: 75135
### Re: Reading the textbook[ENDORSED]
I think reading the textbook would be helpful even if you don't understand it. That way you get a taste of the material so during class the lecture will flow better.
Wed Oct 04, 2017 11:11 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 115
Views: 10318
### Re: All students read this sig fig post[ENDORSED]
What are the subtraction/addition/multiplication/division rules for sig figs? I understand the concept of using the numbers given but don't know what you're referring to with the "rules" For multiplication and division, the rule is to end up with an answer with sig figs equivalent to the ...
Mon Oct 02, 2017 3:48 pm
Forum: Significant Figures
Topic: All students read this sig fig post [ENDORSED]
Replies: 115
Views: 10318
### Re: All students read this sig fig post[ENDORSED]
During the calculations I would just keep a long string of numbers after the decimal until I come to the answer and then apply sig fig rules to get 3 sig figs cuz 4 sig figs might not be enough to avoid round off error. I'm not sure what's meant by "inconsistent." As long as you avoid roun...
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https://mathcs.chapman.edu/~jipsen/structures/doku.php?id=partial_monoids&rev=1614028296
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Partial monoids
Abbreviation: PMon
Definition
A \emph{partial monoid} is a structure $\mathbf{A}=\langle A,\cdot,e\rangle$, where $\langle A,\cdot\rangle$ is a partial semigroup and
$e$ is an identity for $\cdot$: $x\cdot e=x=e\cdot x$ for all $x\in A$.
Morphisms
Let $\mathbf{A}$ and $\mathbf{B}$ be partial monoids. A morphism from $\mathbf{A}$ to $\mathbf{B}$ is a function $h:A\rightarrow B$ that is a homomorphism: $h(e)=e$ and if $x\cdot y\ne *$ then $h(x \cdot y)=h(x) \cdot h(y)$.
Examples
Example 1: Any partial semigroup with a new element $e$ and $\cdot$ extended with $x\cdot e=x=e\cdot x$.
Properties
Classtype first-order
Finite members
$\begin{array}{lr} f(1)= &1\\ f(2)= &3\\ f(3)= &15\\ f(4)= &112\\ f(5)= &\\ f(6)= &\\ f(7)= &\\ f(8)= &\\ f(9)= &\\ f(10)= &\\ \end{array}$
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mersenneforum.org Welcome to "Five or Bust!"
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2008-10-09, 23:04 #1 philmoore "Phil" Sep 2002 Tracktown, U.S.A. 45F16 Posts Welcome to "Five or Bust!" The distributed computing project Seventeen or Bust is attempting to prove the following: Conjecture: $78557$ is the smallest positive odd integer $k$such that $k\cdot 2^n+1$ is composite for any positive integer $n$. The method of inquiry is to attempt to find, for each positive odd $k<78557$, a positive integer value of $n$ such that $k\cdot 2^n+1$ is prime. The name Seventeen or Bust was chosen because no such prime was known for exactly 17 such values of $k$ when the project began. Currently, after the discovery of 11 large primes, there are 6 sequences which are still being tested for primes. What happens if we allow $n$ to take negative values? We have: $k\cdot 2^{-n}+1={{k+2^n}\over{2^n}}$. For $k=78557$, we can verify that the numerator $78557+2^n$ is composite for any positive integer $n$, and we make the following Conjecture: $78557$ is the smallest positive odd integer $k$ such that $k+2^n$ is composite for any positive integer $n$. Again, we would like to find, for each positive odd $k<78557$, a positive integer $n$ such that $k+2^n$ is prime. Of the 39,278 such values of $k$, a proven prime value is known for all but 33 values. Of these 33, probable prime values of $k+2^n$ are known for 28 of them. This leaves 5 values of $k$ for which neither a prime nor a probable prime value of $k+2^n$ is known. The primary purpose of this project is to search these 5 sequences for large probable primes. Hence, "Five or Bust". There was an ongoing search on this problem in 2002, and Payam Samidoost maintained a web-site on the status entitled The dual Sierpinski problem search. I began searching the 8 unresolved sequences in August 2007, and I have discovered 3 more large probable primes. The most recent discovery, $8543+2^{1191375}$, found in June, is currently listed at 358,640 decimal digits as the largest known probable prime at the website of Henri and Renaud Lifchitz, PRP Records, Probable Primes Top 10000. Numbers on this list have passed a number of tests, usually strong primality tests, that all prime numbers will pass and most composite numbers will fail. Because we do not have a factorization of $N\pm 1$, we cannot at present prove these numbers prime, but a theorem of Damgard, Landrock, and Pomerance implies for example that the probability that this large example is actually composite is less than $10^{-650}$. This project is technically therefore not a prime search project, but rather a probable prime search project. As the current search limit on $n$ is up to 1.4 million, any new discovery will qualify as a record probable prime, unless of course someone else finds a larger one in the meantime. Because more $k$ values are eliminated at smaller values of $n$, this "dual" Sierpinski search appears to be a little easier than the original search being pursued by Seventeen or Bust. On the other hand, because SB is searching for provable primes, they have the hope of actually producing a mathematical theorem as a result, whereas this search is only producing convincing evidence but not a proof. The main two sub-projects are PRP testing and sieving. For now, PRP testing will be done with Prime95 version 25, and sieving can be done with Geoff's sr2sieve program. Details on how to get started are in those particular threads. Last fiddled with by philmoore on 2011-02-17 at 00:14 Reason: replaced link to Samidoost's web-page with cached version
2008-10-09, 23:25 #2 philmoore "Phil" Sep 2002 Tracktown, U.S.A. 3×373 Posts Proof that 78557 is a Sierpinski number A Sierpinski number is an odd positive integer $k$ such that $k\cdot2^n+1$ is composite for any positive integer $n$. Theorem: $78557\cdot2^n+1$ is composite for any positive integer $n$. Proof: If $n\equiv 0 \bmod 2$, $78557\cdot2^n+1$ is divisible by 3. If $n\equiv 1 \bmod 4$, $78557\cdot2^n+1$ is divisible by 5. If $n\equiv 7 \bmod 12$, $78557\cdot2^n+1$ is divisible by 7. If $n\equiv 11 \bmod 12$, $78557\cdot2^n+1$ is divisible by 13. If $n\equiv 3 \bmod 36$, $78557\cdot2^n+1$ is divisible by 73. If $n\equiv 15 \bmod 36$, $78557\cdot2^n+1$ is divisible by 19. If $n\equiv 27 \bmod 36$, $78557\cdot2^n+1$ is divisible by 37. It is instructive to compare this to the proof for the dual sequence: Theorem: $78557+2^n$ is composite for any positive integer $n$. Proof: If $n\equiv 0 \bmod 2$, $78557+2^n$ is divisible by 3. If $n\equiv 3 \bmod 4$, $78557+2^n$ is divisible by 5. If $n\equiv 5 \bmod 12$, $78557+2^n$ is divisible by 7. If $n\equiv 1 \bmod 12$, $78557+2^n$ is divisible by 13. If $n\equiv 33 \bmod 36$, $78557+2^n$ is divisible by 73. If $n\equiv 21 \bmod 36$, $78557+2^n$ is divisible by 19. If $n\equiv 9 \bmod 36$, $78557+2^n$ is divisible by 37.
2008-10-14, 21:56 #3 philmoore "Phil" Sep 2002 Tracktown, U.S.A. 3·373 Posts I see that my probable prime record at http://www.primenumbers.net/prptop/prptop.php has just been displaced to #2, but I have no doubt that this project will find a new record. I would guess that we will find our first new probable prime in the range of n < 3 million.
2008-10-15, 23:32 #4 gd_barnes May 2007 Kansas; USA 25·17·19 Posts This is an EXCELLENT project idea, Phil! I was curious about a similar-type effort on the Riesel side quite sometime back. I did a little searching here and there on it. One of the things that I recall struck me as odd is that the lowest remaining k to not have a prime on the RieselSieve project, k=2293, also did not have a prime or PRP up to n=~100K for 2^n-2293. The k is so much smaller than any other remaining k that it is very surprising that it doesn't have a prime or PRP yet on either of the 'dual' sides. One thing that makes such an effort unusual for Riesels is that you get into the case of negative numbers. In other words, do we consider -3, -5, -7, -11, etc. to be prime? I would think that most people would say no but others might debate otherwise. I also did some PRP testing a while back for all k<20 up to n=~150K for 2^n-k and 2^n+k. A majority of it had already been done, as was evidenced by PRP's reported on the site that you mentioned, but I did find several PRP's for the larger k's in the group as well as a missing PRP for k=3 on one side so it was nice to know that double-checking does pay off from time to time. My machines are pretty well tied up through the end of the year but I'll look to contribute here in early 2009. Good luck with the project! Gary P.S. edit: I just now noticed that Phil's cat here is strumming one of its paws and its eyes blink. Pretty cool! lol Last fiddled with by gd_barnes on 2008-10-15 at 23:36
2010-02-23, 01:48 #5 Batalov "Serge" Mar 2008 Phi(4,2^7658614+1)/2 24A916 Posts Phil went retro! ...but indeed his cat was always strumming (it is even scarier when it stares without blinking): Attached Images
2010-02-23, 03:52 #6 philmoore "Phil" Sep 2002 Tracktown, U.S.A. 21378 Posts Do you notice that I don't really blink? I just close my eyes halfway... don't want to miss anything.
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http://sp.marksharks.com/ms/g07/s01/solved_questions/ncert/NCERT_EXERCISE_LESSON7.html/index.html
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Chapter 7: Congruence of Triangles
# Question: 1
Complete the following statements:
a. Two line segments are congruent if __________.
b. Among two congruent angles, one has a measure of $70°$; the measure of the other angle is _________.
c. When we write $\angle \text{A}=\angle \text{B}$, we actually mean ___________.
## Solution
a. They have the same length
b. $70°$
c. $m\angle \text{A}=m\angle \text{B}$
# Question: 2
Give any two real-life examples for congruent shapes.
## Solution
(i) Two footballs
(ii) Pages of same book
# Question: 3
If $\Delta \text{ABC}\cong \Delta \text{FED}$ under the correspondence $\text{ABC}↔\text{FED}$ write all the corresponding congruent parts of the triangles.
## Solution
Given: $\Delta \text{ABC}\cong \Delta \text{FED}$
The corresponding congruent parts of the triangles are:
(i) $\angle \text{A}↔\angle \text{F}$
(ii) $\angle \text{B}↔\angle \text{E}$
(iii) $\angle \text{C}↔\angle \text{D}$
(iv) $\overline{\text{AB}}↔\overline{\text{FE}}$
(v) $\overline{\text{BC}}↔\overline{\text{ED}}$
(vi) $\overline{\text{AC}}↔\overline{\text{FD}}$
# Question: 4
## If $\Delta \text{DEF}\cong \Delta \text{BCA}$, write the part(s) of $\Delta \text{BCA}$ that correspond to
(i) $\angle \text{E}$
(ii) $\overline{\text{EF}}$
(iii) $\angle \text{F}$
(iv) $\overline{\text{DF}}$
## Solution
Given: $\Delta \text{DEF}\cong \Delta \text{BCA}$.
(i) $\angle \text{E}↔\angle \text{C}$
(ii) $\overline{\text{EF}}↔\overline{\text{CA}}$
(iii) $\angle \text{F}↔\angle \text{A}$
(iv) $\overline{\text{DF}}↔\overline{\text{BA}}$
# Question: 1
Which congruence criterion do you use in the following?
a. Given : $\text{AC}=\text{DF}$
$\text{AB}=\text{DE}$
$\text{BC}=\text{EF}$
So, $\Delta \text{ABC}\cong \Delta \text{DEF}$
b. Given: $\text{ZX}=\text{RP}$
$\text{RQ}=\text{ZY}$
$\angle \text{PRQ}=\angle \text{XZY}$
So, $\Delta \text{PQR}\cong \Delta \text{XYZ}$
c. Given: $\angle \text{MLN}=\angle \text{FGH}$
$\angle \text{NML}=\angle \text{GFH}$
$\text{ML}=\text{FG}$
So, $\Delta \text{LMN}\cong \Delta \text{GFH}$
d. Given: $\text{EB}=\text{DB}$
$\text{AE}=\text{BC}$
$\angle \text{A}=\angle \text{C}=\text{90}°$
So, $\Delta \text{ABE}\cong \Delta \text{CDB}$
## Solution
a. By $\text{SSS}$ congruence criterion,
since it is given that $\text{BC}=\text{EF}$
The three sides of one triangle are equal to the three corresponding sides of another triangle.
Therefore, $\Delta \text{ABC}\cong \Delta \text{DEF}$
b. By $\text{SAS}$ congruence criterion,
since it is given that and $\angle \text{PRQ}=\angle \text{XZY}$
The two sides and one angle in one of the triangle are equal to the corresponding sides and the angle of other triangle.
Therefore, $\Delta \text{PQR}\cong \Delta \text{XYZ}$
c. By $\text{ASA}$ congruence criterion,
since it is given that $\angle \text{MLN}=\angle \text{FGH,}$
The two angles and one side in one of the triangle are equal to the corresponding angles and side of other triangle.
Therefore, $\Delta \text{LMN}\cong \Delta \text{GFH}$
d. By $\text{RHS}$ congruence criterion,
since it is given that $\text{EB}=\text{BD,}$ $\angle \text{A}=\angle \text{C}=\text{90}°$
Hypotenuse and one side of a right angled triangle are respectively equal to the hypotenuse and one side of another right angled triangle.
Therefore, $\Delta \text{ABE}\cong \Delta \text{CDB}$
# Question: 2
You want to show that $\Delta \text{ART}\cong \Delta \text{PEN}$
a. If you have to use $\text{SSS}$ criterion, then you need to show
(i) $\text{AR}=$
(ii) $\text{RT}=$
(iii) $\text{AT}=$
b. If it is given that $\angle \text{T}=\angle \text{N}$ and you are to use SAS criterion, you need to have
(i) $\text{RT}=$
and
(ii) $\text{PN}=$
c. If it is given that $\text{AT}=\text{PN}$ and you are to use ASA criterion, you need to have
(i) $?$
(ii) $?$
## Solution
a. Using SSS criterion, $\Delta \text{ART}\cong \Delta \text{PEN}$
(i) $\text{AR}=\text{PE}$
(ii) $\text{RT}=\text{EN}$
(iii) $\text{AT}=\text{PN}$
b. Given: $\angle \text{T}=\angle \text{N}$
Using SAS criterion, $\Delta \text{ART}\cong \Delta \text{PEN}$
(i) $\text{RT}=\text{EN}$
(ii) $\text{PN}=\text{AT}$
c. Given: $\text{AT}=\text{PN}$
Using ASA criterion, $\Delta \text{ART}\cong \Delta \text{PEN}$
(i) $\angle \text{RAT}=\angle \text{EPN}$
(ii) $\angle \text{RTA}=\angle \text{ENP}$
# Question: 3
You have to show that $\Delta \text{AMP}\cong \Delta \text{AMQ}$. In the following proof, supply the missing reasons.
Steps Reasons (i) $\text{PM}=\text{QM}$ (i) …………. (ii) $\angle \text{PMA}=\angle \text{QMA}$ (ii) …………. (iii) $\text{AM}=\text{AM}$ (iii) …………. (iv) $\Delta \text{AMP}\cong \Delta \text{AMQ}$ (iv) ………….
## Solution
Steps Reasons (i) $\text{PM}=\text{QM}$ (i) Given (ii) $\angle \text{PMA}=\angle \text{QMA}$ (ii) Given (iii) $\text{AM}=\text{AM}$ (iii) Common (iv) $\Delta \text{AMP}\cong \Delta \text{AMQ}$ (iv) $\text{SAS}$ congruence rule
# Question: 4
In , $\angle \text{B}=\text{40}°$ and $\angle \text{C}=\text{110}°$.
In , $\angle \text{Q}=\text{40}°$ and $\angle \text{R}=\text{110}°$.
A student says that $\Delta \text{ABC}\cong \Delta \text{PQR}$ by $\text{AAA}$ congruence criterion. Is he justified? Why or why not?
## Solution
No, because the two triangles with equal corresponding angles need not be congruent. In such a correspondence, one of them can be an enlarged copy of the other.
# Question: 5
In the figure, the two triangles are congruent. The corresponding parts are marked. We can write $\Delta \text{RAT}\cong ?$
## Solution
In the figure, given two triangles are congruent. So, the corresponding parts are:
$\text{A}↔\text{O}$, $\text{R}↔\text{W}$, $\text{T}↔\text{N}$,
We can write,
$\Delta \text{RAT}\cong \Delta \text{WON}$ [By $\text{SAS}$ congruence rule]
# Question: 6
Complete the congruence statement:
$\Delta \text{BCA}\cong ?$ $\Delta \text{QRS}\cong ?$
## Solution
In $\Delta \text{BAT}$ and $\Delta \text{BAC}$, given triangles are congruent so the corresponding parts are:
$\text{B}↔\text{B}$, $\text{A}↔\text{A}$, $\text{T}↔\text{C}$,
Thus,
$\Delta \text{BCA}\cong \Delta \text{BTA}$ [By $\text{SSS}$ congruence rule]
In $\Delta \text{QRS}$ and $\Delta \text{TPQ}$, given triangles are congruent so the corresponding parts are:
$\text{P}↔\text{R}$, $\text{T}↔\text{Q}$, $\text{Q}↔\text{S}$,
Thus,
$\Delta \text{QRS}\cong \Delta \text{TPQ}$ [By $\text{SSS}$ congruence rule]
# Question: 7
In a squared sheet, draw two triangles of equal areas such that
(i) the triangles are congruent.
(ii) the triangles are not congruent.
What can you say about their perimeters?
## Solution
In a squared sheet, draw $\Delta \text{ABC}$ and $\Delta \text{PQR}$.
When two triangles have equal areas and
(i) these triangles are congruent, i.e., $\Delta \text{ABC}\cong \Delta \text{PQR}$ [By $\text{SSS}$ congruence rule]
Then, their perimeters are same because length of sides of first triangle are equal to the length of sides of another triangle by $\text{SSS}$ congruence rule.
(ii) But, if the triangles are not congruent, then their perimeters are not same because lengths of sides of first triangle are not equal to the length of corresponding sides of another triangle.
# Question: 8
## Solution
Let us draw two triangles $\text{PQR}$ and $\text{ABC}$.
All angles are equal, two sides are equal except one side. Hence, $\Delta \text{PQR}$ are not congruent to $\Delta \text{ABC}$.
# Question: 9
If $\Delta \text{ABC}$ and $\Delta \text{PQR}$ are to be congruent, name one additional pair of corresponding parts. What criterion did you use?
## Solution
$\Delta \text{ABC}$ and $\Delta \text{PQR}$ are congruent. Then one additional pair is $\overline{\text{BC}}=\overline{\text{QR}}$
Given:
$\angle \text{C}=\angle \text{R}$
$\overline{\text{BC}}=\overline{\text{QR}}$
Therefore,
$\Delta \text{ABC}\cong \Delta \text{PQR}$ [By $\text{ASA}$ congruence rule]
# Question: 10
Explain, why $\Delta \text{ABC}\cong \Delta \text{FED}$
## Solution
Given:
In $\Delta \text{ABC}$ and $\Delta \text{FED}$
$\angle \text{A}=\angle \text{F}$ [Given]
Using angle sum property in both triangles and we find that $\angle \text{C}=\angle \text{D}$
Also, $\text{BC}=\text{ED}$ [Given]
Therefore,
$\Delta \text{ABC}\cong \Delta \text{FED}$ [By $\text{ASA}$ congruence rule]
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https://forum.allaboutcircuits.com/threads/questions-about-the-operation-of-a-50w-audio-amplifier.117590/
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# Questions about the operation of a 50W audio amplifier
#### janjan22
Joined Jun 10, 2015
14
Hi all,
I have some questions about the operation of a 50W amplifier attached as an image.
1. Which path follows the DC base current of Q2 (input pair)? For Q1 there is a DC patch through the input source and 47K resistor, but for Q2 it doesn't look so obvious where the DC base current is going. I think the only possibility is through the load?
2. What's the purpose of R12? In other audio designs it seems that sometimes this resistor is not used.
3. It is said that the output signal of an input pair is a current signal (transconductance stage). But in this schematic the base of Q4 (VAS transistor) is connected through R12 to the collector output voltage of Q1. So it seems it is voltage driven, because it is connected to the collector output voltage. Then why it is said that the output signal of the input pair is a current signal?
I have some other questions, but I'll save them for later. Thanks in advance.
#### Jony130
Joined Feb 17, 2009
5,230
Q5 provide a path for Q2 base current.
Ask the designers, in this case IRF designed this amp.
http://www.irf.com/technical-info/appnotes/an-948.pdf
I do not see any compensation capacitor, so maybe they add such a "big" resistor in series with VAS base for stabilization purpose.
Or maybe they want to reduce the influence of a Q4 hie (rin) variation. Because hie is a load for a LTP (long tail pair).
But in this case the "current" from LTP is the signal. So how can R12 has any effect on the Q4 base current?
#### Jony130
Joined Feb 17, 2009
5,230
Oscillation of the amplifier caused by capacitive coupling to the base of the driver transistor, Q4, is suppressed by the addition of a series resistor, R14 (page 4)
#### janjan22
Joined Jun 10, 2015
14
Thanks for your fast response. That PDF is very useful. I didn't know it was a design from IRF. Coming back to the questions:
1. You say there is a path for the DC bias current through Q5, does that mean Q5 is always (slightly conducting)?
2. Thanks, that's more clear now.
3. Ok, I was assuming the base of Q4 is voltage driven because it is connected to the output collector voltage of Q1. Do you mean to say that R12 has no influence on the base current of Q4? So that the base current would be equal regardless of R12 included or not?
4. It is said in the IRF app. note that the bias current is said by R11 and R10 (In the PDF R8 and R9).
Quote "The class A driver transistor, Q4, operates at a bias current determined by resistors R8, R9, nominally 5mA."
But the bias of a transistor is always set at the base right? The base current sets the collector current and the collector load determines the collector output voltage. Then why they say it is said by R8 and R9?
#### Jony130
Joined Feb 17, 2009
5,230
1. You say there is a path for the DC bias current through Q5, does that mean Q5 is always (slightly conducting)
Yes, the P-MOS provide a path for Q2 base current. Also notice that this base current is very small Ic2 ≈ (35V - 0.65V)/(15kΩ + 1.2kΩ) * 0.5 ≈ 1mA and the base current is around 1mA/hfe = 10μA range.
3. Ok, I was assuming the base of Q4 is voltage driven because it is connected to the output collector voltage of Q1. Do you mean to say that R12 has no influence on the base current of Q4? So that the base current would be equal regardless of R12 included or not?
I was talking about a "signal" current , not DC quiescent current. R12 is in series with Q4 base and thanks to this IR12 = IbQ4.
And R12 will have a small effect on the Ib4. We can easily neglect it.
R12 job is to form a low pass filter together with Cbse and Q4 miller capacitance and kept the amp stable.
4. It is said in the IRF app. note that the bias current is said by R11 and R10 (In the PDF R8 and R9).
Quote "The class A driver transistor, Q4, operates at a bias current determined by resistors R8, R9, nominally 5mA."
But the bias of a transistor is always set at the base right? The base current sets the collector current and the collector load determines the collector output voltage. Then why they say it is said by R8 and R9?
And they are right. In this type of a circuit the negative feedback loop help as set the DC bias point in the circuit, we have exactly the same situation as in the op amp, in fact this circuit is just a big and powerful op amp.
And because of this (without any input signal) the output voltage is around 0V thanks to negative feedback and differential amp (Q1 , Q2).
So, the voltage at Q4 collector is Vout - Vgs and at bottom of a R10 is Vout + Vgs. And from there we can find Ic4 as a:
Ic4 ≈ (35V - 4V)/(R10+R11) ≈ 5.7mA
Last edited:
#### MikeML
Joined Oct 2, 2009
5,444
... I didn't know it was a design from IRF. ...
The owners of CircuitsToday steal from everybody without attribution...
#### GopherT
Joined Nov 23, 2012
8,012
The owners of CircuitsToday steal from everybody without attribution...
Agreed. They can't even copy and paste correctly on some topics - humorous to me but sad to anyone trying to build a project based on their instructions.
#### janjan22
Joined Jun 10, 2015
14
I'm going to read this other threads and probably come back after the weekend. It seems there is more to this subject then appears from the surface
Yes, the P-MOS provide a path for Q2 base current. Also notice that this base current is very small Ic2 ≈ (35V - 0.65V)/(15kΩ + 1.2kΩ) * 0.5 ≈ 1mA and the base current is around 1mA/hfe = 10μA range.
1. To calculate Ic2 you assumed that the base voltage of Q2 is at 0V? I don't see how this is at 0V.
2.Is the base of Q1 also at 0V?
3.
And from there we can find Ic4 as a:
Ic4 ≈ (35V - 4V)/(R10+R11) ≈ 5.7mA
Where does the 4V come from in this calculation?
Thanks
#### Jony130
Joined Feb 17, 2009
5,230
1. To calculate Ic2 you assumed that the base voltage of Q2 is at 0V? I don't see how this is at 0V.
2.Is the base of Q1 also at 0V?
Yes, I assumed that Q1 and Q2 base is at 0V (without input signal of course). And this is a very reasonable assumption in real life base voltage is not larger than 0.6V or I should say it should be less than 0.6V.
You do not know why it is so? Try answer this question:
What is the voltage at Vin an Vout for this circuit (without input signal)
Where does the 4V come from in this calculation?
N-MOS Vgs voltage. Again this is an assumption because it is impossible to know the exact value. And this is also the reason why nobody makes exact calculations in this type of a circuit, too many unknowns. And in real circuit this is not the most important part.
#### janjan22
Joined Jun 10, 2015
14
That opamp example makes it more clear. Vout should be 0V when input is also 0V. My confusion remains with the bias curent of Q4 VAS transistor.
In transistor theory it is always learned that the collector current is determined by the Vbe voltage (Ebers-Moll model) or input current (current model).
This collector current will flow regardless of load dimension this current will flow (within compliance). When there wouldn't be any signal at the base of Q4 there would be no collector current. I understand your calculation "Ic4 ≈ (35V - 4V)/(R10+R11) ≈ 5.7mA", but at the same time the bias current through Q4 must be set by an input signal at the base right?
#### Jony130
Joined Feb 17, 2009
5,230
Do you understand how negative feedback work?
As we establish for Vin = 0V we have Vout= 0V thanks to negative feedback action. And because of this output voltage will finally reach 0V.
This mines that Q4 is driven by Q1 (voltage drop across R13) in such a way to achieve this goal (Vout = 0V). And when circuit finally "set" vout at 0V the Q4 quiescent current must be equal to Ic4 ≈ (35V - 4V)/(R10+R11) ≈ 5.7mA.
If for example we lower R10 and R11 value (2K). The voltage at Q4 collector will rise from 4V to Vc4 = 35V - 4kΩ*5.7mA = 12.2V.
This rise in Q4 collector will appears as a Vout voltage rise from 0V to 8.2V. This increase in output voltage will reduce Q2 Vbe voltage and Q2 will reduce his collector current. So more current from R3 can now flows into Q1.
Q1 collector will increase --->more voltage drop across R13---> large Q4 Vbe---> Q4 collector current will increase his value---> large voltage drop across R10+R11---> Vc4 will drop-->Vout will decrease. And circuit will stop all this action when Vout = 0V. And IcQ4 will have a new value Ic = (35V - 4V)/4kΩ = 7.75mA
I hope you finally "see" how R10+R11 "sets" the Q4 quiescent current, and all this is possible thanks to negative feedback.
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## anonymous 4 years ago find axial stress Delete Cancel Submit
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1. anonymous
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when you calculate for dM in 2nd step dM$\int\limits_{0}^{b}x^2 \sigma d x$ i cant figure out how x^2 pops out need help here ...
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apart from previous one I have another conceptual doubt |dw:1349027770783:dw| suppose this is a slender rod ,acted by tensile load P as previous and if I want to calculate axial stress at area b*b then whats is area should be taken whether its 4b^2 or b^2 ? I mean whole or the concerned area.....
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i get the solution you can remove now and thanks
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https://www.nature.com/articles/s41598-018-31818-3?error=cookies_not_supported&code=e00f03b6-ee87-452e-ac41-690c07b94aa1
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Article | Open | Published:
# Complexity, rate, and scale in sliding friction dynamics between a finger and textured surface
## Abstract
Sliding friction between the skin and a touched surface is highly complex, but lies at the heart of our ability to discriminate surface texture through touch. Prior research has elucidated neural mechanisms of tactile texture perception, but our understanding of the nonlinear dynamics of frictional sliding between the finger and textured surfaces, with which the neural signals that encode texture originate, is incomplete. To address this, we compared measurements from human fingertips sliding against textured counter surfaces with predictions of numerical simulations of a model finger that resembled a real finger, with similar geometry, tissue heterogeneity, hyperelasticity, and interfacial adhesion. Modeled and measured forces exhibited similar complex, nonlinear sliding friction dynamics, force fluctuations, and prominent regularities related to the surface geometry. We comparatively analysed measured and simulated forces patterns in matched conditions using linear and nonlinear methods, including recurrence analysis. The model had greatest predictive power for faster sliding and for surface textures with length scales greater than about one millimeter. This could be attributed to the the tendency of sliding at slower speeds, or on finer surfaces, to complexly engage fine features of skin or surface, such as fingerprints or surface asperities. The results elucidate the dynamical forces felt during tactile exploration and highlight the challenges involved in the biological perception of surface texture via touch.
## Introduction
When we explore objects via touch, complex frictional forces are produced by means of which we are able to perceive surface features, to identify the object at hand, and to facilitate grasping or manipulation. In contrast to vision and audition, the origin of tactile signals, which arise mainly through contact between the skin and touched objects, is unclear. These interactions produce dynamic mechanical deformations that span multiple length and time scales shaped by geometry and mechanics of the touched surface and heterogeneous hand tissues. The resulting stress patterns excite activity in thousands of mechanoreceptive nerve fibers that innervate the skin, translating mechanical stresses into temporally and spatially precise neural information1. The variation in these patterns with movement make it possible to infer properties of touched surfaces, including roughness2, shape3, adhesion4, texture1, bumps and edges5.
Because of the complexity of finger-surface interactions, it is difficult to relate mechanical signals felt by the finger to the surface being sensed. Sliding contact between the finger and a textured surface, even one that is macroscopically smooth6, yields rapid stress fluctuations7,8 that can propagate widely in the skin9. The established duplex theory of texture perception indicates that temporal variation in friction forces, rather than spatial variations, dominate the perception of fine surface textures8. However, the manner in which time-varying forces produced during tactile sliding encode surface properties is not fully understood. Ameliorating this could elucidate the mechanisms of touch perception, and inform the engineering of new technologies for tactile sensing and feedback.
The difficulties in understanding these mechanical interactions can be traced to the nonlinear constitutive behavior of fingertip tissues10,11, the complexities of frictional phenomena12, including the moisture content of the fingertip skin12,13,14, stick-slip transitions15,16,17, the presence of non-Coulombic regimes18, effects of fingerprints19,20. and surface shape induced skin deformations. Thus, during sliding contact of the skin with even simple surfaces such as sinusoidal gratings6,21,22, or braille dots23, forces fluctuate greatly in time. Existing mechanical models based on simplified24 or continuum biomechanics25,26, or signal models, including nonlinear autoregressive processes6, are unable to fully account for the forces produced during tactile sliding, or relate them to surface properties or other interaction parameters. Numerical simulations often involve unreasonable simplifications, omitting physical effects like the aforementioned27,28, and are difficult to compare with measurements, limiting their utility for explaining tactile interactions.
In this study, we sought to ascertain whether the scale- and rate-dependence of friction force fluctuations during tactile sliding could be explained via a numerical model that accounts for the main geometric and mechanical features of the finger, the counter surface, and their contact. We investigated contact forces that were produced during sliding of real fingers on textured contact surfaces with known geometry, and simulated forces based on finite element method (FEM) simulations with equivalent surface shapes and sliding speeds. These simulations accounted for tissue geometry and heterogeneity, dissipation, deformation, hyperelasticity, and interfacial adhesion. We compared the numerical results with experiments for different surface wavelengths, scanning speeds, and contact conditions. Because of the complex dynamics involved in these interactions, we analyzed measured and simulated frictional forces in the time, space, and frequency domains using linear and nonlinear methods, including recurrence plot analysis29,30. The results revealed that the model has greater predictive power for higher sliding speeds and for the coarser surfaces. Based on these discrepancies, and the analytical results, we identified key factors affecting frictional forces produced at different scales and regimes. We discuss implications of the results for understanding human abilities of surface texture perception.
## Results
We compared a total of 528 time-resolved friction force trajectories FT(t) produced by 9 different index fingers sliding on sinusoidally textured surfaces with 60 simulated force trajectories. The measured and simulated force trajectories were produced in six conditions that varied in sliding speed (v = 80, 120 mm/s), and the wavelength (λ = 1, 2, 3 mm) of the sinusoidal surface height function h(x). For analysis, we converted forces to the spatial domain, FT(x), using the tracked location x(t) of the finger (see Methods). Repeated trials in simulated conditions began from different initial conditions. The results revealed similarities between the measured and simulated force trajectories at both velocity levels and all three texture wavelengths. In all cases, forces exhibited fluctuations due to interactions between the epidermal ridges (i.e. fingerprints) and the sinusoidal surface, and concomitant rapid changes in contact (Fig. 1). The ratio of the standard deviation to the signal amplitude was largest for the measured force data, indicating that there was greater variance in the experiments than in the simulations.
### Spatial Frequency Content
The magnitude spectra A(f) of force fluctuations exhibited power law variations with surface frequency f, that is A(f) ~ 1/fα, as expected in sliding friction interactions and observed in prior studies31. The spatial patterns of frictional forces reflected the periodicities of the textured samples, exhibiting faster oscillations at smaller surface wavelengths, λ. The oscillations were quasiperiodic, varying in phase and amplitude within and between trials (Fig. 1a,b).
The trial to trial variance in the spatial spectrum of forces was smaller for the simulated data than the measured data (Fig. 1c,d), indicating that variations in simulation initial conditions, coupled with tissue and contact mechanics, were not sufficient to reproduce force variations as large as those that we empirically measured. This can be partly attributable to the multiple real fingers represented in the data set, but may also be because the model is effectively smooth at the microscale, in contrast to real surfaces.
The spatial spectra of both simulated and measured signals exhibit prominent maxima at spatial frequencies corresponding to integer multiples of the fundamental spatial frequencies (λ−1 = 1, 0.5, 0.33 mm−1). The simulated forces produced by the finer surfaces (λ = 1, 2 mm) exhibit an additional maximum with a frequency of approximately 2 mm−1, which we could associate with the 0.47 mm spacing of the epidermal ridges. No similar frequency manifested in the measured force patterns. As discussed below, this difference is likely attributable to the parallel configuration of fingerprint ridges in the model, which contrast with the varying ridge orientation of real fingers. As analyzed in the supplementary information (Supplementary Data S5), and further discussed below, we associated this, and frequency splitting in the spectrum for the λ = 3 mm, v = 80 mm/s condition, with partial out-of-phase ridge motion, which could occur due to the effectively parallel ridge configuration in the model. This did not appear in the measurements, where ridge orientation varies across the fingertip.
### Recurrence Patterns
We used recurrence analysis to capture the nonlinear correlations in the signals (see Methods), yielding recurrence matrices $${{\bf{R}}}_{ij}(\varepsilon )={\rm{\Theta }}(\varepsilon -\Vert {{\bf{x}}}_{i}-{{\bf{x}}}_{j}\Vert )$$, and their ensemble averages $${ {\mathcal R} }_{ij}=\overline{{{\bf{R}}}_{ij}}$$. The latter captured similarities in the force trajectories at different relative phases across many trials, revealing conserved patterns of quasiperiodic behavior. The prominent diagonal lines reflect self-similarities in the dynamical state at different times across trials for simulated or measured data (Fig. 2), and their spacing δ along the opposing diagonal reflect intervals over which the dynamical state approximally recurred. For both measured and simulated data, in three of the conditions (λ = 2 mm, v = 80 mm/s; λ = 3 mm, v = 80, 120 mm/s), the line spacing was close to the wavelength of the sample (δ = 2, 3, 3 mm respectively). The value of δ was shifted lower for the λ = 3 mm, v = 80 mm/s condition in agreement with our finding (discussed above) that the corresponding spectral line was shifted to higher frequencies (Supplementary Data S5).
In the remaining three conditions, which included slow or fast sliding on fine (1 mm) surfaces and fast sliding on medium (2 mm) surfaces, the simulated force trajectories included a contribution from lines with fine spacing, δ ≈ 0.47 mm, matching that of the epidermal ridges, in agreement with the spectrum analysis (as noted in the foregoing).
We further quantified the similarity of measured and modeled forces via ensemble averages $${{\mathscr{J}}}_{ij}$$ of joint recurrence plots $${{\bf{J}}}_{ij}={\rm{\Theta }}({\varepsilon }_{{\bf{x}}}-||{{\bf{x}}}_{i}-{{\bf{x}}}_{j}||)\cdot {\rm{\Theta }}({\varepsilon }_{{\bf{y}}}-||{{\bf{y}}}_{i}-{{\bf{y}}}_{j}||)$$ over all 880 combinations of computed vs. measured forces in matched conditions λ, v. The prominent diagonal line features revealed high degrees of similarity between measured and simulated force trajectories even over long distances (Fig. 3), indicating that the geometry and mechanics that are represented in the model reproduced force trajectories similar to those that were empirically observed. The line distance δ increased with λ, and the line orientation was almost exactly θ = π/4 from vertical in all conditions, indicating that the simulated and measured forces were similarly quasiperiodic.
We analyzed the JRP data using standard recurrence quantification analyses, based on line length statistics (Table 1), which measured the mutual similarity of the measured and simulated forces at relative times. Mean line length L was larger at high sliding speed (v = 120 vs. 80 mm/s) for every wavelength (λ = 1, 2, 3 mm). Surprisingly, this indicates that the model had greater predictive power at higher speeds, when forces fluctuated more rapidly in time, than at lower speeds (mean $$\overline{L}$$ = 0.13 vs. 0.19 for v = 80, 120 mm/s), albeit with somewhat greater variability (resp. mean $$\overline{{\sigma }_{L}}$$ = 0.055 vs 0.085). The results also show that, at both speeds, simulated and measured forces became most similar for the longest surface periods.
## Discussion
In this study, we compared sliding friction forces produced by a real finger with those that are predicted via a numerical multi-layer fingertip model that accounts for the geometry, mechanics, and interfacial forces produced by a real finger. The model captured the most salient phenomena that we empirically observed in matched conditions, including quasiperiodic force fluctuations and their dependence on the spatial period of the underlying texture. In measured and simulated forces, the nonlinearity of finger tissue and contact mechanics was reflected in force components that were excited at multiples of the fundamental surface (spatial) frequency (1.0, 0.5, 0.33 mm−1).
Through recurrence analyses, including pairwise comparisons across the ensemble of measured and simulated forces in each condition, we determined that the main features of the measured friction force trajectories were captured by the model, and that the model had greatest predictive power for higher speeds and coarser surfaces. The results were qualitatively highly similar when the analysis was restricted to individual participants (Fig. 4b), and in individual trial analyses for each participant and simulations (see representative examples in Fig. S3). The recurrence analysis revealed greatest similarity between measured and simulated forces (Fig. 3), as quantified by recurrence length statistics, for faster sliding (v = 120 mm/s) and larger-scale surface textures (λ = 3 mm), see Table 1. This was consistent with our findings from the spectrum analysis. Together, these results suggest that tactile exploration at low speeds on fine surfaces elicits force patterns that are more difficult to predict from such a model, even though they fluctuate more slowly in time. This may partly explain why, as observed nearly a century ago9, perceptual discrimination of fine surface texture becomes impaired as the speed of sliding decreases. However, as discussed below, effects of small scale features, including fingerprint ridges further complicate this interpretation.
At low speed and smaller wavelengths, complex, multiperiod oscillations are observed in measured and simulated forces (Fig. 2), and our linear and nonlinear analyses suggest that this could be attributed to the ability of slow speeds and fine textures to engage small scale features, including finger ridges, in ways that were more complex than are captured in the model. Notably, for slow sliding or finer surface textures, the frequency spectra of the simulated forces included frequency components due to the 0.47 mm fingerprint ridge spacing of the epidermal layer, and apparent mixing frequencies with the surface period. This is due to the effectively parallel geometry of fingerprint ridges in the model relative to the surfaces (see Figs 5 and S4).
While we did not observe such a frequency component in simulated forces for the coarsest surfaces, a closer analysis of the volumetric simulations revealed that out-of-phase motion of epidermal ridges was responsible for this (see Supplementary Information S4). At the slowest speed, this attenuated the frequency component associated with the surface wavelength. A further result was a decrease in bulk stresses which could, in principle, reduce tactile sensation for surfaces that coupled to the dynamics of a real finger in such a manner. This may merit further investigation.
In contrast to these simulations, during tactile exploration of real surfaces, fingerprint ridges are oriented in multiple directions. Viewed along the direction of motion, this results in a range of effective ridge spacings, and thus would be expected to elicit a distribution of force frequencies, rather than a single dominant frequency, as would be consistent with our measurements.
While our experimental observations in this study were dominated by frequencies due to the surface geometry, previous research has reported friction force components associated with spatial frequencies 1/λRidge of the fingerprint ridges32, and that such effects can be robust to contact orientation19. These effects have been linked to a hypothesized sensory function of finger ridges. As noted above, their absence in our measured data could be due to irregularities in real fingerprint patterns, their nonuniform alignment with the surface texture along the direction of motion, or to the moisture-induced plasticization of fingerprint ridges.
At larger length scales, combined effects of finger elasticity and surface periodicities may also help to explain the higher trial to trial variability of friction forces produced by finer surfaces. For these surfaces, contact conditions change rapidly, yielding many distinct contact regions, and contributing to the complexity of the resulting force patterns33. As we have recently shown, such multi-contact surfaces are not only produced during contact with high relief textures, but also generically manifest during tactile exploration of smooth, isolated surface features, such as localized bumps34. The gaps in contact that occur during tactile interaction with relief surfaces can enhance bulk stress gradients that are captured by sensory mechanoreceptors of touch, and further research is needed in order to clarify their role in tactile sensation.
While contact-dependence represents a nonlinearity in the system, coupled to the high-dimensional tissue dynamics, other sources of variation in the interfacial or dynamic conditions that were not modeled here could also contribute to force fluctuations during tactile surface exploration. In addition to fingerprint effects discussed above, additional potential sources of variation that arise from the complex tribological behavior of the finger pad12,13,35 include the moisture-driven plasticization of the stratum corneum (which we minimized methodologically) and partial stick-slip motions. Further research to investigate these factors is warranted. In addition, the nonlinear dynamics of heterogeneous tissues could yield significant variation in time-resolved friction forces arising from even proximal initial conditions.
## Methods
We investigated the geometric and mechanical origins of force production during frictional sliding of a finger against textured surfaces. We analyzed measurements of time varying contact forces produced as real fingers slid on relief surfaces, numerically simulated the same system, and compared both using signal processing and recurrence plot analysis and quantification. This study was directed at understanding physical phenomena, and did not comprise human research (US Department of Health and Human Services 45 CFR 46.102(f): No identifiable or private data were used or coded).
### Measured Force Production
This study is based on data from a custom force and position measurement apparatus (Fig. 4d,e) from our previous work, in which we collected normal and tangential force data produced while fingers slid over fabricated undulating surfaces6, as we summarize here. We measured forces via piezoelectric sensors (Model 9712A5, Kistler Instruments, Switzerland) supporting a textured relief surfaces on an aluminum tray (top dimensions 120 × 25 mm) via a compliant mechanism36, and captured the data to maximize the available signal bandwidth after digitization (55.6 μs sample period, 16 bits).
The textured relief surfaces were sinusoidal gratings with surface height function h(x) = A sin (2πx/λ), which varied in wavelength λ and amplitude A. Wavelength and amplitude were coupled through a scale parameter, A(λ) = A0λ with A0 = 0.1 mm, ensuring that the maximum slope was constant for all surfaces. The range of wavelengths (1 to 3 mm) was similar to those used in previous studies of texture perception from end point forces37,38. The surfaces were 3D printed (Objet 30, Stratasys Inc., Boston, USA) with high resolution (100 μm) yielding surfaces that were sinusoidally textured with a smooth finish. Finger motion was tracked using an optical system (model V120: Trio Natural Point, Corvallis, OR), via a reflective marker attached to the fingernail, with sampling rate 120 Hz, spatial resolution 200 μm.
The high resolution force and motion data were produced by the fingers of nine individuals (five male and four female, age range 19 to 28). Digit I (index finger) of the dominant hand slid over the surfaces ten times at two different speeds (80 mm/s and 120 mm/s), as entrained through auditory feedback, from left to right. The finger was not restrained, in order to preserve the mechanical effect of the joints of the hand. The fingers contacted the surface with a touch force of F = 0.3 N, as entrained through a visual scale. The two speeds and three wavelengths yielded a total of six conditions. We excluded a small number of trials with periodic or transient stick slip behavior that exhibited large transient force magnitude fluctuations. 88 measured force signals in each condition (v, λ) were used for the analysis. Prior to data collection in each condition, each sinusoidal grating and finger pad had been cleaned using isopropyl alcohol.
### Numerical Friction Simulation
To clarify the dynamics of frictional sliding during tactile surface exploration, we simulated sliding friction interactions in conditions mirroring those of the real measurements, using FEM software (COMSOL Multiphysics, COMSOL Group, Sweden), inspired by prior numerical studies of finger biotribology27. In order to ensure efficient computation, we chose a two-dimensional modeling approach. We constructed an axially symmetric fingertip model, accounting for the mechanics and the main anatomical features of the finger and of the touched surface. The model accommodates the heterogeneity of finger tissues, including the nail, bone, dermis and epidermis (thicknesses 0.8 and 0.7 mm39,40), epidermal ridges, and subcutaneous tissues (Fig. 4a,b). We set the center-to-center distance of the ridges to be 0.47 mm, consistent with prior research41. We omitted papillae between the dermis and epidermis from the model, as there is little evidence that they play a role in frictional dynamics. We selected material properties, incorporating hyperelasticity, so that the nonlinear constitutive behavior of real fingers under indentation (compression) testing was reconstructed42 (Fig. 5 and Supplementary Information S1).
At each time, the numerical model computed bulk and interfacial stresses and strains due to sliding contact between the finger and surface, yielding normal and tangential stress components σp(x) and σr(x) at each point x on the contact interface. Their directions correspond to the surface orientation at x, given here via the angle α(x) = tan−1 [dh(x)/dx] formed by the tangent of the surface h(x) and the horizontal. The normal and tangential stress are related by a Coulomb-Amonton term σr(x) = μσp(x), with a coefficient of friction μ that is independent of the applied load. This assumption has theoretical and empirical support over a wide range of conditions43,44, although at low forces modest variations of μ with the normal force applied by a finger are observed18. At each time t, the friction force on the finger is given by projecting stress components in the direction tangent to the surface and integrating over the contact surface $${\mathscr{C}}$$, yielding
$$F={\int }_{{\mathscr{C}}}{\sigma }_{p}(x)\{\sin (\alpha (x))+\mu \,\cos \,(\alpha (x))\}dx\,dz$$
(1)
where z spans a size D in the plane of the model.
To match the measurement conditions, the indentation of the finger was controlled to yield a normal force of 0.3 N, and the friction coefficient was set to μ = 0.8. Further detail about the model parameters and simulation details are provided in the Supplementary Informations S1S3.
Prior research13,35 including work in our lab6, has reported large trial to trial frictional force fluctuations, which were partly attributed to small (≈100 μm) variations in initial contact conditions. In order to capture this source of variability, we repeated simulations from an array of ten initial positions in every condition.
### Linear Analysis of Frictional Forces
We analyzed real and simulated friction force signals FT(t) in order to ascertain the factors determining force fluctuations from surface texture. We isolated force signal components of the measured and simulated time series that were most relevant to tactile perception using band pass filtering (zero phase, corner frequencies 15 and 500 Hz). We translated these signals from the time to the spatial domain using the centroid of the finger position x(t), yielding spatial domain force signals FT(x). We analyzed the spatial frequency content in the measured and simulated signals using the Fourier transform, yielding ensembles of frequency domain signals FT(f).
### Nonlinear Analysis of Frictional Forces
Linear measures, including Pearson’s cross correlation, can yield low similarity scores between measurement trials in otherwise identical conditions, and are prone to spurious effects. The complexity of the force signals as well as the nonlinearity of the mechanics also raised the question of whether linear methods would capture signal attributes of interest. Thus, we investigated the similarity between measured and simulated frictional signals using recurrence plot analysis, in order to extract multi-mode and nonlinear dependencies, to compare the series across time, and to quantify similarities in the force patterns of simulated and measured trials. The recurrence analysis method embeds the time series fi = f(ti), i = 1, 2, …, N, into a state space of dimension D, in which a state vector trajectory
$${{\bf{x}}}_{i}=({f}_{i},\,{f}_{i+\tau },\,\ldots ,\,{f}_{i+(D-1)\tau }),\,i=1,2,\ldots ,K$$
(2)
of length K = N − (D − 1)τ is obtained as the span of D samples each spaced by a delay time τ centered at each indexed time ti. The recurrence matrix
$${{\bf{R}}}_{ij}(\varepsilon )={\rm{\Theta }}(\varepsilon -\Vert {{\bf{x}}}_{i}-{{\bf{x}}}_{j}\Vert )$$
(3)
with i, j = 1, 2, … K describes the similarity of the state at time ti with the state at a different time tj and depends on the embedding dimension D, delay time τ, and a distance threshold value ε. Here Θ is the Heaviside step function, ||·|| is the Euclidean distance, and K is duration of the state vector. Thus, Rij is 1 when xi and xj are closer than ε, and 0 otherwise. To compare state vector trajectories xi and yj associated with distinct simulated and measured time series fi = f(ti) and gj = g(tj), we compute a joint recurrence matrix
$${{\bf{J}}}_{ij}(\varepsilon )={\rm{\Theta }}({\varepsilon }_{x}-\Vert {{\bf{x}}}_{i}-{{\bf{x}}}_{j}\Vert )\,\cdot \,{\rm{\Theta }}({\varepsilon }_{y}-\Vert {{\bf{y}}}_{i}-{{\bf{y}}}_{j}\Vert )$$
(4)
with i, j = 1, 2, …, K, so that all time instances are highlighted, for which two different time series trajectories recur simultaneously in their respective phase space. To analyze ensembles of trials in respective conditions, we computed collective recurrence and joint recurrence matrices
$${ {\mathcal R} }_{ij}=\sum _{\alpha =1}^{{N}_{l}}\,{{\bf{R}}}_{ij,\alpha },\,{{\mathscr{J}}}_{ij}=\sum _{\alpha =1}^{{N}_{l}}\sum _{\beta =1}^{{M}_{l}}\,{{\bf{J}}}_{ij,\alpha \beta }$$
(5)
with i, j = 1, 2, …, K, accommodating data of Nl = 10 simulated and Nl = 88 measured trials in each condition (v, λ), yielding a total of parwise 880 combinations. The recurrence matrix Rij,α (Eq. 3) belongs to simulated or measured trial number α, and for the joint recurrence matrix Jij,αβ (Eq. 4) α and β index the measured and simulated trials. We set the distance threshold ε adaptively for each Rij,α and Jij,αβ to yield a constant densities of 10 and 35% respectively. The joint recurrence analysis was repeated for the simulated and measured force signals, at each speed (v = 80, 120 mm/s) and surface wavelength (λ = 1, 2, 3 mm), yielding a total of twelve collective recurrence plots $${ {\mathcal R} }_{ij}(v,\lambda )$$, and six collective joint recurrence plots $${{\mathscr{J}}}_{ij}(v,\lambda )$$ that comprised 880 measured vs simulated trial combinations. We quantified diagonal structures in each $${{\mathscr{J}}}_{ij}(v,\lambda )$$ by computing the distribution P(L) of line length values, and reported summary statistics in terms of per-condition mean values L and standard deviations σL for all 880 simulated and measured trial combinations, as well as statistics grouped across speeds. Further details, including the selection of the embedding parameters, are provided in the Supplementary Information S4.
## Data Availability
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## Acknowledgements
The authors would like to thank Yitian Shao for stimulating conversation and Alexander Eden for helpful comments on the model calibration. This work was supported by the US National Science Foundation (NSF) award CNS-1446752 and CNS-1527709.
## Author information
### Affiliations
1. #### Department of Electrical and Computer Engineering, Media Arts & Technology Program, and Department of Mechanical Engineering, University of California, Santa Barbara, California, 93106, USA
• Behnam Khojasteh
• & Yon Visell
2. #### Department of Electrical and Computer Engineering, Drexel University, Philadelphia, 19104, USA
• Marco Janko
### Contributions
B.K. developed the model, performed the simulations, analyzed the data, prepared the figures, and drafted the manuscript. M.J. conducted the measurements, analyzed the data, prepared the figures, and edited the manuscript. Y.V. analyzed the data, edited the manuscript, and supervised the research. All authors conceived of the study and designed the study. All authors gave final approval for publication.
### Competing Interests
The authors declare no competing interests.
### Corresponding author
Correspondence to Yon Visell.
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https://www.cfd-online.com/W/index.php?title=Source_term_linearization&diff=4404&oldid=4403
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# Source term linearization
(Difference between revisions)
Revision as of 05:55, 7 December 2005 (view source)Tsaad (Talk | contribs)← Older edit Revision as of 05:55, 7 December 2005 (view source)Tsaad (Talk | contribs) Newer edit → Line 21: Line 21: $S_P = -3T_P^{*2}$
$S_P = -3T_P^{*2}$
- =References= + ==References== #{{reference-book|author=Patankar, S.V.|year=1980|title=Numerical Heat Transfer and Fluid Flow|rest=ISBN 0070487405, Hemisphere Publishing Corporation, USA.}} #{{reference-book|author=Patankar, S.V.|year=1980|title=Numerical Heat Transfer and Fluid Flow|rest=ISBN 0070487405, Hemisphere Publishing Corporation, USA.}} #{{reference-paper|author=Murthy, Jayathi Y.|year=1998|title=Numerical Methods in Heat, Mass, and Momentum Transfer|rest=Draft Notes, Purdue University ([http://widget.ecn.purdue.edu/%7Ejmurthy/me608/main.pdf/ download])}} #{{reference-paper|author=Murthy, Jayathi Y.|year=1998|title=Numerical Methods in Heat, Mass, and Momentum Transfer|rest=Draft Notes, Purdue University ([http://widget.ecn.purdue.edu/%7Ejmurthy/me608/main.pdf/ download])}} #{{reference-paper|author=[http://webfea-lb.fea.aub.edu.lb/fea/me/CFD/ Darwish, Marwan]|year=2003|title=CFD Course Notes|rest=Notes, American University of Beirut}} #{{reference-paper|author=[http://webfea-lb.fea.aub.edu.lb/fea/me/CFD/ Darwish, Marwan]|year=2003|title=CFD Course Notes|rest=Notes, American University of Beirut}} - #{{reference-paper|author=[http://jedi.knows.it/ Saad, Tony]|year=2005|title=Implementation of a Finite Volume Unstructured CFD Solver Using Cluster Based Parallel Computing|rest=Thesis, American University of Beirut}}
# Introduction
In seeking the solution of the general transport equation for a scalar $\phi$, the main objective is to correctly handle the non-linearities by transforming them into linear form and then iteratively account for the non-linearity. The source term plays a central role in this respect when it is non-linear. For example, in radiation heat transfer, the source term in energy equation is expressed as fourth powers in the temperature.
When the source is constant and independent of the conserved scalar, the finite volume method assumes that the value of S prevails of the control volume and thus can be easily integrated. For a given control volume P, we obtain
$\int_{\Omega} S d\Omega = S\Omega \,$
## Picard's Method
Picard's method is the most popular method used in conjunction with the finite volume method. For a given control volume P, we start by writing the source term as
$S = S_C + S_PT_P \,$
where $S_C$ denotes the constant part of S and $S_P$ denotes the coefficient of $\phi_P$ (not the value of S at P). This allows us to place $S_P$ in the coefficients for $\phi_P$.
Let $\phi_P^*$ denote the value of $\phi_P$at the current itertaion. We now write a Taylor series expansion of S about $\phi_P^*$ as
$S = S^* + \left ( \frac {\partial S}{\partial \phi} \right ) ^* \left ( \phi_P - \phi_P^* \right )$
therefore
$S_C = S^* - \left ( \frac {\partial S}{\partial \phi} \right ) ^* \phi_P^*$
$S_P = \left( \frac {\partial S}{\partial \phi} \right ) ^*$
where $\left ( \frac {\partial S}{\partial \phi} \right ) ^*$ is the gradient of S evaluated at $\phi_P^*$.
As an illustrative example, consider $S = -T^3 + 10 \,$. Following Picard's method, we have
$\left( \frac {\partial S}{\partial \phi} \right ) = -3T^2$
$S_C = -T_P^{*3} +10 + 3T_P^{*2}T_P^* = 2T_P^{*3} +10$
$S_P = -3T_P^{*2}$
## References
1. Patankar, S.V. (1980), Numerical Heat Transfer and Fluid Flow, ISBN 0070487405, Hemisphere Publishing Corporation, USA..
2. Murthy, Jayathi Y. (1998), "Numerical Methods in Heat, Mass, and Momentum Transfer", Draft Notes, Purdue University (download).
3. Darwish, Marwan (2003), "CFD Course Notes", Notes, American University of Beirut.
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http://en.wikipedia.org/wiki/F%c3%bchrerdiskriminantenproduktformel
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# Conductor-discriminant formula
In mathematics, the conductor-discriminant formula or Führerdiskriminantenproduktformel, introduced by Hasse (1926, 1930) for abelian extensions and by Artin (1931) for Galois extensions, is a formula calculating the relative discriminant of a finite Galois extension $L/K$ of local or global fields from the Artin conductors of the irreducible characters $\mathrm{Irr}(G)$ of the Galois group $G = G(L/K)$.
## Statement
Let $L/K$ be a finite Galois extension of global fields with Galois group $G$. Then the discriminant equals
$\mathfrak{d}_{L/K} = \prod_{\chi \in \mathrm{Irr}(G)}\mathfrak{f}(\chi)^{\chi(1)},$
where $\mathfrak{f}(\chi)$ equals the global Artin conductor of $\chi$.[1]
## Example
Let $L = \mathbf{Q}(\zeta_{p^n})/\mathbf{Q}$ be a cyclotomic extension of the rationals. The Galois group $G$ equals $(\mathbf{Z}/p^n)^\times$. Because $(p)$ is the only finite prime ramified, the global Artin conductor $\mathfrak{f}(\chi)$ equals the local one $\mathfrak{f}_{(p)}(\chi)$. Because $G$ is abelian, every non-trivial irreducible character $\chi$ is of degree $1 = \chi(1)$. Then, the local Artin conductor of $\chi$ equals the conductor of the $\mathfrak{p}$-adic completion of $L^\chi = L^{\mathrm{ker}(\chi)}/\mathbf{Q}$, i.e. $(p)^{n_p}$, where $n_p$ is the smallest natural number such that $U_{\mathbf{Q}_p}^{(n_p)} \subseteq N_{L^\chi_\mathfrak{p}/\mathbf{Q}_p}(U_{L^\chi_\mathfrak{p}})$. If $p > 2$, the Galois group $G(L_\mathfrak{p}/\mathbf{Q}_p) = G(L/\mathbf{Q}_p) = (\mathbf{Z}/p^n)^\times$ is cyclic of order $\varphi(p^n)$, and by local class field theory and using that $U_{\mathbf{Q}_p}/U^{(k)}_{\mathbf{Q}_p} = (\mathbf{Z}/p^k)^\times$ one sees easily that $\mathfrak{f}_{(p)}(\chi) = (p^{\varphi(p^n)(n - 1/(p-1))})$: the exponent is
$\sum_{i=0}^{n-1}(\varphi(p^n) - \varphi(p^i)) = n\varphi(p^n) - 1 - (p-1)\sum_{i=0}^{n-2}p^i = n\varphi(p^n) - p^{n-1}.$
## Notes
1. ^ Neukirch 1999, VII.11.9.
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http://link.springer.com/article/10.1023/A:1025157101089
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, Volume 115, Issue 3, pp 283-305
# Does Belief Have an Aim?
Rent the article at a discount
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## Abstract
The hypothesis that belief aims at the truth has been used to explain three features of belief: (1) the fact that correct beliefs are true beliefs, (2) the fact that rational beliefs are supported by the evidence and (3) the fact that we cannot form beliefs `at will’. I argue that the truth-aim hypothesis cannot explain any of these facts. In this respect believing differs from guessing since the hypothesis that guessing aims at the truth can explain the three analogous features of guessing. I conclude that, unlike guessing, believing is not purposive in any interesting sense.
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https://www.physicsforums.com/threads/confusion-about-killing-horizon-in-carroll.867661/
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# I Confusion about killing horizon in Carroll
1. Apr 18, 2016
### hideelo
In the opening paragraph of section 6.3 Carroll defines a killing horizon to be a null hypersurface Σ where some killing vector field χμ becomes null. Later (on page 247 if you have the book) when distinguishing between static and stationary space times, he says that in a stationary, but not static spacetime, we still have the killing field Kμ = (∂t)μ , but it wont become null at the killing horizon. How is that possible? By definition that seems wrong. How do you have a killing horizon if thats not where your killing field becomes null?
TIA
2. Apr 18, 2016
### hideelo
NVM got it ;-)
Draft saved Draft deleted
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https://iq.opengenus.org/euclidean-vs-manhattan-vs-chebyshev-distance/
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# Euclidean vs Manhattan vs Chebyshev Distance
#### similarity measurement euclidean distance manhattan distance chebyshev distance
Euclidean distance, Manhattan distance and Chebyshev distance are all distance metrics which compute a number based on two data points. All the three metrics are useful in various use cases and differ in some important aspects which we bring out in this article.
### Visual difference
This image summarizes the difference in the three distance metrics:
### Computation
In a N dimensional space, a point is represented as (x1, x2, ..., xN).
Consider two points P1 and P2:
P1: (X1, X2, ..., XN)
P2: (Y1, Y2, ..., YN)
Then, the euclidean distance between P1 and P2 is given as:
$$\sqrt{{(x1-y1)}^2\ +\ {(x2-y2)}^2\ +\ ...\ +\ {(xN-yN)}^2}$$
The manhattan distance between P1 and P2 is given as:
$$|x1-y1|\ +\ |x2-y2|\ +\ ...\ +\ |xN-yN|}$$
The chebyshev distance between the two points P1 and P2 is:
Chebyshev distance = MAXIMUM (|xi - yi|) where i is 1 to N
### Usage in Chess
In chess, all the three distances are used as follows:
• the distance between squares on the chessboard for rooks is measured in Manhattan distance
• kings and queens use Chebyshev distance
• bishops use the Manhattan distance (between squares of the same color) on the chessboard rotated 45 degrees, i.e., with its diagonals as coordinate axes.
• To reach from one square to another, only kings require the number of moves equal to the distance (euclidean distance) rooks, queens and bishops require one or two moves
#### OpenGenus Foundation
The official account of OpenGenus IQ
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https://tex.stackexchange.com/questions/41587/how-to-intersect-an-arc-with-a-line-without-calculating-the-angle?noredirect=1
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# How to Intersect an arc with a line without calculating the angle
I'd like to draw an optics-related figure, for which I need to draw several beams with varying opening angles, which will need to be labeled.
What I've come up at the moment (boiled down to a minimal example) is below:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{intersections}
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\begin{document}
\centering
\begin{preview}
\begin{tikzpicture}
\coordinate (origin) at (0,0);
\coordinate (screen-top) at (5,2);
\coordinate (screen-bottom) at (5,-2);
\draw [dashed,name path=beam] (origin) -- (screen-top) -- (screen-bottom) -- cycle;
\draw [green,name path=circle] (0,0) circle (1);
\path [name intersections={of=beam and circle,name=arc}];
\draw [bend left] (arc-1) to node [midway,right] { $$\alpha$$} (arc-2) ;
\end{tikzpicture}
\end{preview}
\end{document}
Now I have a problem with this code. I can't seem to be able to automatically figure out the correct bending angle of the path between the intersections (the creen circle and the beam), so the bend is not 'nice', as seen in the figure below.
I know that I can manually set the bending angle with [bend left=19] instead of [bend left], but doing this manually for all drawings seems like not doing it the TikZ-way.
Does anyone have a tip for automatically calculating the bending angle for the path so it automatically matches a circle going through that point? Automatically means for different beam angles and 'screen' sizes and positions (which can be set in the code...)
Here are two solutions. The first clips a circle. The second actually computes the required angle, then draws the arc.
The code is
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{intersections}
\usetikzlibrary{calc}
\begin{document}
%option 1
\begin{tikzpicture}
\coordinate (origin) at (0,0);
\coordinate (screen-top) at (5,2);
\coordinate (screen-bottom) at (5,-2);
\draw [dashed,name path=beam] (origin) -- (screen-top) -- (screen-bottom) -- cycle;
\draw [green,name path=circle] (0,0) circle (1);
\clip (origin) -- (screen-top) -- (screen-bottom) -- cycle;
\node[right] at (1,0) {$\alpha$};
\end{tikzpicture}
%option 2
\begin{tikzpicture}
\coordinate (origin) at (0,0);
\coordinate (screen-top) at (5,2);
\coordinate (screen-bottom) at (5,-2);
\draw [dashed,name path=beam] (origin) -- (screen-top) -- (screen-bottom) -- cycle;
\draw [green,name path=circle] (0,0) circle (\radius);
\draw let
\p{a} = ($(screen-top) - (origin)$),
\p{b} = ($(screen-bottom) - (origin)$),
\n{inner product} = {(\x{a}/1cm)*(\x{b}/1cm) + (\y{a}/1cm)*(\y{b}/1cm)},
\n{la} = {veclen(\x{a}/1cm,\y{a}/1cm)},
\n{lb} = {veclen(\x{b}/1cm,\y{b}/1cm)},
\n{cosine} = {\n{inner product}/(\n{la}*\n{lb})},
\n{half-angle} = {0.5*acos(\n{cosine})}
in
(arc-2) arc[start angle=-\n{half-angle},end angle=\n{half-angle},radius = \radius] node[right] at ($(origin) + (\radius,0)$){$\alpha$};
\end{tikzpicture}
\end{document}
Comment for Habi: You may replace the code defining the arc by the following line, in which the arc starts at arc-1:
(arc-1) arc[start angle=\n{half-angle},end angle=-\n{half-angle},radius = \radius] node[right] at ($(origin) + (\radius,0)$){$\alpha$};
• Using a clipped circle as 'workaround' is quite elegant. I'll use this, also because the second option doesn't compile for me (with '! Package pgf Error: No shape named arc-2 is known.' as error). – Habi Jan 19 '12 at 17:03
• @Habi: see comment at bottom of my post. – Frédéric Jan 19 '12 at 18:26
With tkz-euclide, you need only one line.
\documentclass{scrartcl}
\usepackage{tkz-euclide}
\usetkzobj{all}
\begin{document}
\begin{tikzpicture}
\tkzDefPoint(1,1){O} \tkzDefPoint(3,-1){A} \tkzDefPoint(4,2){B}
\tkzDrawArc[R with nodes, color=blue](O,2cm)(A,B)
\tkzDrawArc[R with nodes, color=red](O,2cm)(B,A)
\tkzDrawLines[add = 0 and .5](O,A O,B)
\tkzDrawPoints(O,A,B)
\tkzLabelPoints[below](O,A,B)
\end{tikzpicture}
\end{document}
This is not a direct answer to your question, however, since you know where origin of the rays is and to which points they lead, here is another approach:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc,decorations.markings}
\tikzset{arcnode/.style={
decoration={
markings, raise = 2mm,
mark=at position 0.5 with {
\node[inner sep=0] {#1};
}
},
postaction={decorate}
}
}
\newcommand*\marktheangle[5]{
\draw[thick,arcnode={#5}] let \p2=($(#2)-(#1)$),%
\p3=($(#3)-(#1)$),%
\n2 = {atan2(\x2,\y2)},%
\n3 = {atan2(\x3,\y3)}%
in ($(\n2:#4)+(#1)$) arc (\n2:\n3:#4);
}
\begin{document}
\begin{tikzpicture}
\draw[style=help lines] (-0.5,-0.5) grid[step=1cm] (4.5,2.5);
\node[draw,red,circle,minimum width=2cm] (O1) at (1,1) {};
\node[draw,red,circle,minimum width=1cm] (O2) at (3.5,1.5) {};
% Define 4 points "out there"
\node (a) at (1.5,-0.8) {$a$};
\node (b) at (-5mm,-5mm) {$b$};
\coordinate (c) at (4.5,1);
\coordinate (d) at (3,2.5);
\draw[loosely dashed,blue] (O1.base) -- (a) (O1.base) -- (b); % Draw the lines
\draw[loosely dashed,green] (O2.base) -- (c) (O2.base) -- (d); %Draw the lines
% the code for the arc labeling
\marktheangle{O1}{a}{b}{1cm}{$\alpha$}
\marktheangle{O2}{d}{c}{5mm}{$\beta$} % Mind the order for label positioning.
\end{tikzpicture}
\end{document}
Now, in his answer to this question, Cjorssen mentions that in the new version, one can directly place a node on an arc. So the whole marking code might be obsolete quite soon or immediately if you wish to use the CVS version. One can further embed these into one nice tikzset definition with better key handling.
• A clever solution, but quite lenghty in terms of code. The other answer to my question suggested simply using a clipped circle, which is what I will go for. Thanks for the work though! – Habi Jan 19 '12 at 17:04
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https://collaborate.princeton.edu/en/publications/lagrangian-transport-by-breaking-surface-waves
|
# Lagrangian transport by breaking surface waves
Luc Deike, Nick Pizzo, W. Kendall Melville
Research output: Contribution to journalArticlepeer-review
28 Scopus citations
## Abstract
The Lagrangian transport due to non-breaking and breaking focusing wave packets is examined. We present direct numerical simulations of the two-phase air-water Navier-Stokes equations describing focusing wave packets, investigating the Lagrangian drift by tracking tracer particles in the water before, during and after the breaking event. The net horizontal transport for non-breaking focusing packets is well described by the classical Stokes drift, both at the surface and in the bulk of the fluid, where the e-folding scale of the evanescent vertical profile is given by the characteristic wavenumber. For focusing wave packets that lead to breaking, we observe an added drift that can be ten times larger than the classical Stokes drift for a non-breaking packet at the surface, while the initial depth of the broken fluid scales with the wave height at breaking. We find that the breaking induced Lagrangian transport scales with the breaking strength. A simple scaling argument is proposed to describe this added drift and is found to be consistent with the direct numerical simulations. Applications to upper ocean processes are discussed.
Original language English (US) 364-391 28 Journal of Fluid Mechanics 829 https://doi.org/10.1017/jfm.2017.548 Published - Oct 25 2017
## All Science Journal Classification (ASJC) codes
• Condensed Matter Physics
• Mechanics of Materials
• Mechanical Engineering
## Keywords
• air/sea interactions
• ocean processes
• wave breaking
## Fingerprint
Dive into the research topics of 'Lagrangian transport by breaking surface waves'. Together they form a unique fingerprint.
|
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http://aas.org/archives/BAAS/v27n2/aas186/abs/S4904.html
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The Integrated Light of M67 and the Spectroscopic CMD''
Session 49 -- Star Clusters in the Milky Way and Other Galaxies
Display presentation, Thursday, June 15, 1995, 9:20am - 4:00pm
## [49.04] The Integrated Light of M67 and the Spectroscopic CMD''
Lewis A. Jones, James A. Rose (University of North Carolina at Chapel Hill), Nelson Caldwell (F.L. Whipple Observatory), Michael J. Tripicco (University of Maryland)
We present intermediate resolution spectroscopic data on M67 in the 4800--5400 \AA~ region. We have spectra of 55 stars extending from the tip of the giant branch down to one magnitude below the turnoff. This data has been applied to the study of stellar populations in elliptical galaxies in two very powerful ways. First, as a 5 Gyr, solar abundance population, M67 represents a prototypical old open cluster which is a likely analog, both in age and metal abundance, to the intermediate'' age populations being found in integrated light studies of elliptical galaxies. We have formed an integrated spectrum of M67 and present it as a fiducial calibrator for the evolutionary synthesis models of Worthey (1994 ApJS, 95, 107). Second, as we have spectra covering a representative CMD for M67 we can examine empirically the behavior of specific spectral features as a function of position along an isochrone. This will begin to provide a much needed understanding of what aspects of stellar populations are being measured by these spectral indices. We present results for 8 Lick spectral indices including H$\beta$, Mg$_{2}$, and several Fe features.
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https://www.ideals.illinois.edu/handle/2142/83840
|
Files in this item
FilesDescriptionFormat
application/pdf
3202105.pdf (5MB)
(no description provided)PDF
Description
Title: Fabrication and Testing of a Microchannel Network Phantom for MRI Velocimetry Author(s): Honecker, Sharon Lynne Doctoral Committee Chair(s): Georgiadis, John G. Department / Program: Mechanical Engineering Discipline: Mechanical Engineering Degree Granting Institution: University of Illinois at Urbana-Champaign Degree: Ph.D. Genre: Dissertation Subject(s): Engineering, Mechanical Abstract: The MRI velocity maps scale with the Reynolds number of the flow. The theoretical average velocity distribution in a single channel is compared to the experimental distribution, with a consistent over-prediction of velocity near the channel edges. Slice thickness, order of image acquisition, partial volume effects, and acceleration effects are investigated, and show little effect on the measured flow rates. Examination of anatomical MR images show that the channels decreased in height during fabrication, which explains some of the over-prediction in flow rates. The remainder of the discrepancy is attributed to random error caused by a combination of a high value of the maximum encoded velocity and a low signal to noise ratio of the images. Issue Date: 2005 Type: Text Language: English Description: 150 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005. URI: http://hdl.handle.net/2142/83840 Other Identifier(s): (MiAaPQ)AAI3202105 Date Available in IDEALS: 2015-09-25 Date Deposited: 2005
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https://imathworks.com/tex/tex-latex-floor-and-ceiling-functions/
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# [Tex/LaTex] ‘Floor’ and ‘ceiling’ functions
symbols
Is there a convenient way to typeset the floor or ceiling of a number, without needing to separately code the left and right parts? For example, is there some way to do $\ceil{x}$ instead of $\lceil x \rceil$?
\usepackage{mathtools}
The command \ceil will do; if called as \ceil*{x} it will add \left and \right; you can also call it as
\ceil[\big]{x} \ceil[\Big]{x} \ceil[\bigg]{x} \ceil[\Bigg]{x}
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https://inquiryintoinquiry.com/2015/02/01/peirces-1880-algebra-of-logic-chapter-3-%E2%80%A2-selection-1/
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## Peirce’s 1880 “Algebra Of Logic” Chapter 3 • Selection 1
### Chapter 3. The Logic of Relatives
#### §1. Individual and Simple Terms
214. Just as we had to begin the study of Logical Addition and Multiplication by considering $\infty$ and $0,$ terms which might have been introduced under the Algebra of the Copula, being defined in terms of the copula only, without the use of $+$ or $\times,$ but which had not been there introduced, because they had no application there, so we have to begin the study of relatives by considering the doctrine of individuals and simples,— a doctrine which makes use only of the conceptions of non-relative logic, but which is wholly without use in that part of the subject, while it is the very foundation of the conception of a relative, and the basis of the method of working with the algebra of relatives.
215. The germ of the correct theory of individuals and simples is to be found in Kant’s Critic of the Pure Reason, “Appendix to the Transcendental Dialectic,” where he lays it down as a regulative principle, that, if
$\begin{array}{lll} a \,-\!\!\!< b & ~ & b \,\overline{-\!\!\!<}\, a, \end{array}$
then it is always possible to find a term $x,$ that
$\begin{array}{lll} a \,-\!\!\!< x & ~ & x \,-\!\!\!< b \\[8pt] x \,\overline{-\!\!\!<}\, a & ~ & b \,\overline{-\!\!\!<}\, x. \end{array}$
Kant’s distinction of regulative and constitutive principles is unsound, but this law of continuity, as he calls it, must be accepted as a fact. The proof of it, which I have given elsewhere, depends on the continuity of space, time, and the intensities of the qualities which enter into the definition of any term. If, for instance, we say that Europe, Asia, Africa, and North America are continents, but not all the continents, there remains over only South America. But we may distinguish between South America as it now exists and South America in former geological times; we may, therefore, take $x$ as including Europe, Asia, Africa, North America, and South America as it exists now, and every $x$ is a continent, but not every continent is $x.$
### References
• Peirce, C.S. (1880), “On the Algebra of Logic”, American Journal of Mathematics 3, 15–57. Collected Papers (CP 3.154–251), Chronological Edition (CE 4, 163–209).
• Peirce, C.S., Collected Papers of Charles Sanders Peirce, vols. 1–6, Charles Hartshorne and Paul Weiss (eds.), vols. 7–8, Arthur W. Burks (ed.), Harvard University Press, Cambridge, MA, 1931–1935, 1958. Volume 3 : Exact Logic, 1933.
• Peirce, C.S., Writings of Charles S. Peirce : A Chronological Edition, Peirce Edition Project (eds.), Indiana University Press, Bloomington and Indianapolis, IN, 1981–. Volume 4 (1879–1884), 1986.
### Resources
This entry was posted in Logic, Logic of Relatives, Mathematics, Peirce, Relation Theory, Semiotics, Sign Relations, Triadic Relations and tagged , , , , , , , . Bookmark the permalink.
### 3 Responses to Peirce’s 1880 “Algebra Of Logic” Chapter 3 • Selection 1
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https://mourafiq.com/2012/04/15/finding-prime-factors.html
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Write code.
# Finding prime factors of x
In a previous post, we showed how any number can be written, in a unique way, as the product of prime numbers.
In this post we will make a simple algorithm to compute this prime numbers.
1 def get_primes(x):
2 non_primes = set()
3 primes = set()
4 for i in range(2, x+1):
5 if x%i == 0 and i not in non_primes:
11 return primes
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http://mathhelpforum.com/calculus/281664-elliptic-curve-cryptography.html
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# Thread: Elliptic Curve Cryptography
1. ## Elliptic Curve Cryptography
.
May I know how to solve the equation as below:
(1) y2 = x3 + x + 1 mod 17
Finding Inverses
Finding Points on the Curve
(2) y2 = x3 + 3x + 1 mod 13
Finding Inverses
Finding Points on the Curve
.
2. ## Re: Elliptic Curve Cryptography
Originally Posted by vokoyo
.
May I know how to solve the equation as below:
(1) y2 = x3 + x + 1 mod 17
Finding Inverses
Finding Points on the Curve
(1) There are algorithms for solving such problems.
or you can use the brute force method
$\displaystyle x^3+x+1$ is a quadratic residue $\displaystyle \pmod {17}$
so it is equal to one of
$\displaystyle \{0,1,2,4,8,9,13,15,16\}$
3. ## Re: Elliptic Curve Cryptography
.
Thank you for your suggestion
Please show me your sample solution draft
so that I can improve my calculus skills
I fact I would like to draw the curve line or point by point
.
4. ## Re: Elliptic Curve Cryptography
.
Please refer to my draft paper as below -
Elliptic Curve Cryptography.pdf
.
5. ## Re: Elliptic Curve Cryptography
17 points
$\displaystyle \{\{0,1\},\{0,16\},\{4,1\},\{4,16\},\{6,6\},\{6,11 \},\{9,5\},\{9,12\},\{10,5\},\{10,12\},\{11,0\},\{ 13,1\},\{13,16\},\{15,5\},\{15,12\},\{16,4\},\{16, 13\}\}$
6. ## Re: Elliptic Curve Cryptography
.
Please show me your draft paper for reference purpose - Important and Urgent
.
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# From betting to “prediction market”
This is the second part of a series on sports betting
Sports betting has long fascinated economists and statisticians. Griffith (1949) showed early on that horse race bettors put too much money on horses that have little chance of winning, and too little on those that have the best chance of winning. This tendency to underbid on the most likely event has been obaserved in all sports betting, where the “most likely event” is calculated on the basis of recent statistics. And it can be explained in a fundamental way by the mechanics of mutual betting: the bettor opposes his beliefs to those of the crowd, because the various bets will determine the odds.
## Predictions, before surveys
Today, in the months leading up to each election, we find ourselves drowned under the polls, conducted every day (and commented on several times a day, as if estimation noise was worth exegesis). As Frédéric Dabi (Deputy Director General of Ifop) pointed out in a debate organised by Risques magazine in 2017, “surveys are an indication of the electoral balance of power, not a prediction”, but it is nevertheless often in the idea of having a prediction that they are used.
But if we go back in time, Rhode & Strumpf (2008) reminds us that other techniques were used, before the idea of surveys became necessary, in particular betting. In 1549, Matteo Dandolo (Ambassador of Veneto) noted that “it is therefore more than clear that the traders are very well informed of the state of the election, and that the employees of the cardinals in conclave (i conclavisti) participate with them in betting, which therefore leads to several tens of thousands of crowns changing hands” as Baumgartner (2003) tells us. Closer to home, betting markets during the elections were popular in the United States until the Second World War. Rhode & Strumpf (2008) suggests several reasons for the loss of interest in the second half of the 20th century: improvements in sampling techniques… and the legalization of horse betting. But online betting sites have revived interest in betting, whatever it may be. Because the sites we mentioned in a previous article are often not limited to sports betting, but also allow betting on a magnitude earthquake, an Oscar winner, or even the observation of the Higgs boson, as proposed by intrade.com, which was liquidated in 2015. As onlinebettingsites.com shows, we could bet on the French elections in 2017, or on the referendum on Brexit (even if for the latter, the predictive markets were not able to reflect the beliefs of the crowds, as an article in The Economist recalls).
Mathématiques du pari-mutuel
The “pari-mutual” theory is not unlike the mutualisation of risks, an important foundation of the insurance mechanism, dear to actuaries. Working in the horse betting markets, Edmund Eisenberg and David Gale obtained, in a short three-page article, Consensus of Subjective Probabilities, relatively general results, as long as the bet is static.
Supposons que I joueurs puissent parier sur J chevaux. Chaque joueur possède une somme totale bi, que l’on normalisera de telle sorte que bi désigne la part de la somme totale misée (et donc b1 +…+ bI =1). Le joueur i peut alors miser la somme bi,j sur le cheval j (avec ici bi,1+…+bi,J = bi). Lorsque les paris sont clôturés, on note pj le montant parié sur le cheval j, autrement dit b1,j+…+bI,j = pj). La contrainte de budget impose que la somme de ces montants soit égale a 1, ce qui donne aux pj une interprétation probabiliste. Nous reviendrons sur l’utilisation de ces « prix » par la suite. On peut aussi noter qj la cote de gain (payoff-odds) définie comme pj-1-1, de telle sorte que pj=(1+ qj) -1. Si on suppose qu’une portion 1-a est gardée par le bookmaker, alors pj= a(1+ qj) -1 et qj =( a -pj)/ pj. Les rendements espérés sur chacun des chevaux doivent être égaux, à l’équilibre, au rendement net attendu, où l’espérance est calculée sous la probabilité p, de manière à refléter les croyances de tous les parieur, soit ici
pjqj+ (1-pj)(-1)= a-1
The key result of the Eisenberg & Gale model is to show that there is a balance in this market. More precisely, the fraction bet on each horse must be equal to the probability of the horse market. To achieve this balance, it is often assumed that the equilibrium ratings are found by an auctioneer (this role will be played by the bookmaker). As Blough (2008) noted, the hypothesis that no wagering is made until the odds are balanced is a hypothesis that is indeed true in horse racing.
If we assume that each bettor is risk neutral (and seeks to maximize his expectation of winning) and that his beliefs are materialized by a probability vectors pi=(pi1,…,piJ) – in the sense that player i thinks that horse j will win with a probability pij – then at equilibrium, if bi,j >0,
pij=pj max{pis/ps}
where argmax{pis/ps}= argmax{pis(qs+1)}
s the horse on which bettor i must bet everything if he bets on a single horse. Blough (2008) elaborates at length on the description of this balance, and extends it to the case where agents potentially have risk aversion (but the same) and potentially different beliefs. This balance is then described as a consensus of belief.
In an article entitled Interpreting the Predictions of Prediction Markets, Charles Manski proposed using this theory to interpret these prices, in conjunction with more traditional approaches in economics, such as Arrow-Debreu prices.
To illustrate this consensus, let us consider a world cup final that should lead either to the victory of A or the victory of B. Let us imagine a contract offering $1 if A wins, and let this contract be offered at price pA. Si on n’autorise pas d’arbitrage, on a une loi du prix unique, et on en déduit que pB = 1-pA. Imaginons un joueur qui pense que la probabilité que A gagne est supérieure à pA, soit, avec les notations précédentes, piA > pA. Dans ce cas, le joueur a intérêt à parier tout son agent sur la victoire de A, c’est-à-dire acheter ce contrat. La demande agrégée pour ce titre sera alors [b1P[p1A > pA]+…+ bI P[pIA > pA]] / pA et on aura un équilibre si la demande agrégée pour les deux titres vérifie [b1P[p1A > pA]+…+ bI P[pIA > pA]] / pA = [b1P[p1A < pA]+…+ bI P[pIA < pA]] / pB de telle sorte que pA = b1P[p1A > pA]+…+ biP[piA > pA]] +…+ bIP[pIA > pA] which allows the prize to be written as an average of the players’ beliefs. It should be noted here that the balance is static, allowing the bookmaker to just set a rating. Recently, Agrawal et al (2014) proposed an algorithm to balance this market in continuous time. It may also be noted that this notion of equilibrium appears in many algorithms, such as in the so-called Fisher market. ## The predictive power of prices But this idea of seeing in the prices an aggregation of players’ beliefs is not new! In 1655, in Van Rekeningh in Spelen van Gelucken, (published in Latin under the title’De Ratiociniis in Aleæ Ludo’), Christiaan Huyghens proposed to extract information on beliefs from prices. In 1671, Wilhelmina de Witt noted that, as the price of a contract paying an annuity until death could be seen as a weighted average of annuities (with a fixed maturity), by observing the prices of the different insurance contracts, probabilities interpreted as probabilities of survival could be extracted. These probabilities are “subjective” as Bruno de Finetti or Frank Ramsey called them. The latter did not see probabilities from a frequentist angle, but saw it as a measure of the degree of belief, which could be measured through bets, in Truth and Probability (1926). This is finally what the theory presented by Kenneth Arrow in 1953, and further developed by Gérard Debreu in 1959, introducing the “Arrow-Debreu prices”, says. Many websites use odds to infer players’ beliefs, which are misrepresented as the probability that a team will win a competition. We can also note the work carried out last summer by doctoral students at the University of Rennes who had compared the odds on online betting sites, and the forecasts obtained by several algorithms (ranging from a naive Bayesian classifier to boosting, SVM or neural networks). A special issue of The Economist, published in 2007, entitled The Future of Futurology, noted that “the most heeded futurists these days are not individuals, but prediction markets, where the informed guesswork of many is consolidated into hard probability”. This idea has now largely returned to the forefront, as predicted in the article by Chen & Pennock (2010) published in AI Magazine. Agrawal, Shipra, Delage, Erick, Peters, Mark, Wang, Zizhuo & Ye, Yinyu (2014). A Unified Framework for Dynamic Prediction Market Design. Operations Research. Baron, Ken & Lange, Jeffrey (2006). Parimutuel Applications In Finance: New Markets for New Risks. Springer. Baumgartner, Frederic (2003) Behind locked doors: a history of papal elections. Palgrave. Blough, Stephen R. (2008) Differences of opinion at the racetrack. In Efficiency of Racetrack Betting Markets, 323-341, World Scientific. Chen, Yiling & Pennock, David (2010). Designing Markets for Prediction. AI Magazine. Decker, Wolfgang & Thuillier, Jean-Paul (2004). Le sport dans l’antiquité. Picard. Eisenberg, Edmund & Gale, David (1959). Consensus of Subjective Probabilities: The Pari-Mutuel Method. Annals of Mathematical Statistics, 30:1, 165-168. Griffith, RM (1949) Odds adjustments by American horse-race bettors. The American Journal of Psychology, 62, 290-294. Manski, Charles (2005) Interpreting the Predictions of Prediction Markets. NBER 10359. Rhode, Paul, W. & Strumpf, Koleman (2008) Historical Political Futures Markets: An International Perspective. NBER 14377. [1] Baron & Lange (2006) discusses the comparison between so-called “risk-neutral” valuation in finance (based on the law of single price and arbitrage), and that relating to mutual betting. They thus speak of “self-hedging” because, in a bet, the bettors share the winnings in proportion to their initial bet. This is reminiscent of the way mutual insurance companies operate, where the money used to compensate victims must correspond to the total premiums charged. # On my way to Chicago Next Wednesday, I will flight to Chicago for the 2019 Risk Analytics Symposium. I will present some recent work on “Insurance Pricing in a Competitive Market”, and take the opportunity to discuss future actuarial pricing games # Talk at the LATECE Seminar Yesterday, I was giving a talk at the LATECE seminar (Laboratory for research on technology for e-commerce), on Insurance Pricing in a Competitive Market… That was in the Computer Science Departement, at UQAM. # La valeur de la vie Un court article, écrit conjointement avec Béatrice Cherrier… Tous les commentaires sont les bienvenus ! En 1928, revenant sur la révolution chinoise de 1925, André Malraux publie son roman Les Conquérants, et glisse « j’ai appris qu’une vie ne vaut rien, mais que rien ne vaut une vie ». Si la formule peut plaire, on imagine qu’elle n’aidera pas trop un décideur public. En 2013, le Commissariat Général à la stratégie et à la prospective, en France, évaluait la valeur d’une vie à 3 millions d’euros. Mais d’où sort ce chiffre ? Et que signifie-t-il vraiment ? # Sauver une vie vaut-il le coup? Chiffrer une vie est en effet un problème auxquels les assureurs, mais aussi les décideurs publics sont confrontés bien plus souvent qu’il n’y paraît. Après l’effondrement du World Trade Center en 2011, le Congrès américain adopta la Loi sur la sécurité du transport aérien et la stabilisation des systèmes. Cette nouvelle loi prévoyait la création d’un fonds spécial pour indemniser les victimes des attentats du 11 septembre 2001. Le montant de l’indemnité, et les personnes qui y auraient droit, seraient décidées par un fonctionnaire tout-puissant. Ce « special master,» Kenneth Feinberg, explique dans un ouvrage qui revient sur son expérience (Feinberg 2006) que le gouvernement souhaitait éviter une avalanche de poursuites pour préjudices corporels. Cela aurait pu plonger l’industrie du transport aérien dans la tourmente. Un cadre très strict fut donc instauré : seules les victimes « ayant recu un traitement à l’hopital dans les 72 heures qui suivirent les attaques », blessées aux abords du World Trade Center et du Pengatone, ainsi que leurs conjoints et enfants – mais pas leurs parents – furent déclarés admissibles à une indemnisation. Le fond accorda plus de 7 milliards de dollars à 5 560 victimes et membres de leur famille. Feinberg se devait, légalement, d’étalonner les dommages et intérêts en fonction de la « valeur financière » de la victime décédée. Il dû ainsi expliquer à la femme d’un pompier, par exemple, que son mari valait moins qu’un courtier d’assurance. En France, le récent passage aux 80km/h sur les routes à deux voies fut aussi partiellement justifié par les vies sauvées. Alors que le premier ministre se réjouissait, en janvier, d’un bilan de 116 vies épargnées, la journaliste Alba Ventura (2019) s’interroge sur RTL : « s’il s’agit de ne sauver qu’une vie, est-ce que ça ne vaut pas le coup ? » Le support radiophonique ajoute à l’ambigüité. Demande-t-elle en fait si « cela ne vaut pas le coût? » Car le problème est bien celui des méthodes employées par la puissance publique pour chiffrer le prix d’une vie, sauvée ou perdue. # La valeur d’une vie humaine comme taux marginal de substitution A la fin des années 1940, l’US Air Force cherchait à maximiser les dommages infligés par ses raids aériens contre l’Union Soviétique. Quand un groupe de chercheurs de la RAND Corporation proposa de faire voler un grand nombre d’avions peu coûteux pour leurrer les défenses aériennes soviétiques, les généraux de l’Air Force refusèrent l’idée, arguant que le coût de la vie des pilotes sacrifiés ne figurait pas dans les calculs. Comme le rappelle Spencer Banzhaf (2014), l’économiste de la défense Jack Hirshleifer choisit alors de calculer valeur de la vie d’un pilote en intégrant le coût de sa formation et de son remplacement. Cette réponse avait l’avantage d’utiliser des grandeurs directement monétaires, et facilement quantifiables. Dans les années 1960, sur l’influence des réflexions autour du capital humain, il fut suggéré d’utiliser une estimation des salaires nets actualisés perçus au cours d’une vie de pilote, supposés refléter l’utilité matérielle du métier. Ces méthodes restaient dans la lignée de celles définies par Louis Dublin et Alfred Lotka pour les compagnies d’assurance dans l’entre-deux-guerres (Cavalin 2016). S’il reprend comme titre le slogan publicitaire d’une compagnie d’assurance, popularisé par des organismes de sécurité routière ( « The Life You Save May Be Your Own »),Thomas Schelling, prix Nobel d’économie en 2005, publie en 1968 un article qui rompt largement avec cette tradition. Il utilise en fait le travail de l’un de ses étudiants (et ancien pilote militaire) Jack Carlson, qui cherchait à évaluer si lcertains investissements en matière de sécurité (pour les pilotes) « valaient le coût ». Le coût d’un système d’éjection des avions B-58 était par exemple de l’ordre de 80 000 dollars, pour un gain substantiel sur la probabilité de survie. C’est cette idée de lier la valeur de la vie avec la notion de risque qui permis à Schelling de développer le concept de « valeur statistique » de la vie. L’innovation majeur de Schelling consistait à impliquer les citoyen.ne.s dans l’évaluation de la valeur de leur propre vie. Puisqu’il était stérile de leur demander de chiffrer leur propre vie de but en blanc, on pouvait en révanche adapter la méthode de Carlson en leur demandant, par exemple, combien ils et elles seraient prêtes à dépenser pour un airbag, ou un traitement médical, qui diminuerait leur taux de mortalité de 1%. Ainsi, en se plaçant dans un diagramme représentant en abscisse la probabilité de survie où l’espérance de vie résiduelle et en ordonnée la richesse, comme sur la Figure 1, pouvait-on construire des courbes d’indifférence liant richesse et survie : quelle somme accepte-t-on (marginalement) de dépenser pour gagner statistiquement un peu de vie, soit en diminuant sa probabilité de décès, soit en allongeant son espérance de vie ? Dans l’exemple ci-dessous, la valeur de la vie est simplement la dérivée de la courbe d’indifférence. Figure 1 : Arbitrage entre espérance de vie et richesse. La valeur de la vie n’est alors pas une grandeur constante, mais dépend de la situation dans laquelle on se trouve. Aussi,$$SVL=\frac{d\omega}{d\text{E}}=\frac{d\omega}{d\text{p}}$$suivant qu’on la calcule par rapport à une variation de l’espérance de vie, ou de la probabilité de décès. Si on a une espérance de vie résiduelle plus ou moins grande (à gauche ou à droite), ou si on est plus ou moins riche (en haut ou en bas), la pente ne sera pas la même. Un exemple classique est celui d’une roulette russe, avec un pistolet a douze chambres. Supposons qu’il y a 3 balles, quel serait le montant que l’on serait prêt à payer pour enlever une balle ? Que deviendrait ce montant s’il y avait 9 balles et qu’on souhaite en enlever plusieurs ? Supposons que la valeur statistique de la vie soit de 3 millions d’euros. Dans le premier cas, la probabilité passe de 3/12 à 2/12, soit $dp_1$=1/12 (soit une baisse de 1/3). Dans le second cas, pour avoir aussi une baisse de 1/3, il faudrait passer de 9/12 a 6/12, soit $dp_2$=3/12. Si on suppose que la valeur statistique de la vie est constante, alors $d\omega_2/d\omega_1=d\text{p}_2/d\text{p}_1$=3, et on devrait être prêt à dépenser 3 fois plus pour une même baisse relative de probabilité de décès. D’un point de vue heuristique, dans le second cas, on est dans une situation un peu désespérée (on a 3 chances sur 4 de mourir) et donc toute solution est bonne à prendre, quelle que soit son prix ! C’est ce que l’on retrouve au travers de la convexité de la courbe de droite sur la Figure 1 : si ma probabilité de décès est élevée (à droite sur l’axe des abscisses), je suis prêt à dépenser beaucoup, pour un faible gain. Cette manière d’évaluer sa propre vie, proposée par Schelling, est souvent, appelée « gunpoint value.» # Sauver ma vie, ou celle d’autrui ? Mais cette approche répond-elle vraiment à la question de départ ? La vie sauvée par une mesure de sécurité contraignante et couteuse est rarement celle de la personne qui prend une décision. Cette tension est particulièrement visible au sein des débats français sur la mesure de la valeur d’une vie, puisqu’à la différence des Etats-Unis celle-ci est largement le fait d’ingénieurs-économistes recrutés par l’Etat afin de mettre en place des politiques publiques visant a augmenter le bien-être des populations. La question de la sécurité routière est à l’origine d’un article fondateur sur le sujet, présenté par deux ingénieurs des ponts et chaussées, Claude Abraham et Jacques Thedie, au colloque annuel de recherche opérationnelle d’Aix-en-Provence en 1960. Répondant à la question « combien une collectivité doit dépenser pour sauver une vie humaine », ils pointent deux types d’éléments à quantifier. Les éléments « objectifs » de nature « économique, » quantifiable en actualisant les pertes de salaires directes et les pertes de production et de consommation, grâce un raisonnement pragmatique qui mélange capital humain et analyse macroéonomique. Par exemple, un homme de 41-45 ans a une valeur de production deux fois supérieure à un homme de 56-60 ans, et sa valeur de consommation est 50% plus élevée. Mais la perte d’un homme de plus de 65 ans est en réalité un gain, ce qui montre l’importance d’intégrer les éléments « affectifs.» Puisque leur évaluation est autrement plus difficile, ceux-ci s’en remettent à l’estimation faite par les tribunaux en matière d’indemnisation des dommages personnels, en particulier l’attribution d’un praetium doloris. Comme le relate Daniel Benamouzig (2005), les aspects théoriques, techniques, éthiques et métaphysiques du principe et de la méthode de la quantification d’une valeur de vie présentés par Abraham et Thédié, et en particulier de l’application de telles méthodes dans le champ de la santé, firent l’objet de débats houleux. Ceux-ci n’ont d’ailleurs toujours pas fait l’objet de résolution consensuelle. Françoise Favre (1970) note par exemple que l’utilisation du calcul économique de la valeur d’une année-vie pour décider si un dépistage systématique du cancer du col de l’utérus doit être mis en place peut conduire par construction une réponse négative. En effet, la valeur marchande du travail féminin qui sert de base au calcul est largement inférieur à celle du travail masculin, ce qui crée des inégalités de traitement hommes-femmes. Adoptant un cadre éthique et théorique empruntant au choix social, Jacques Drèze (1962) propose une méthode de calcul alternative plus proche de celle développée par Schelling. Une décision publique doivent se fonder sur les préférences de la collectivité issues de l’agregation des utilités individuelles pour la décision en question. Une solution aux problèmes de mesure et d’incommensurabilités soulevé par Abraham et Thédié consiste a poser la question aux citoyens « combien la collectivité doit-elle dépenser, selon vous, pour sauver une vie? » L’utilité de la vie peut-être calculée en identifiant la disposition individuelle subjective à payer pour prolonger sa vie en écartant un risque déterminé, ajoute Drèze. Celui-ci conclue que sa méthode conduit à une estimation de la valeur de vie nettement supérieure à celle à laquelle aboutissent ces collègues. La sensibilité des évaluations aux méthodes de calcul, est, aujourd’hui encore, un problème majeur. # Plusieurs méthodes, plusieurs valeurs ? Biausque (2011) reprend plusieurs études, afin d’estimer la valeur (statistique) de la vie, face à des risques environnementaux, de sante ou routier que l’on peut résumer dans le Tableau 1. Environnement Santé Trafic routier Nb d’études 51 250 65 Moyenne (€) 2 455 982 2 574 149 4 884 853 Minimum (€) 24 427 4 450 267 615 Maximum (€) 7 641 706 22 100 000 17 500 000 Tableau 1 : source Biausque (2011). On voit que ces calculs sont complexes, et donnent lieu à des ordres de grandeurs très différents les uns des autres. La variabilité entre individus était évoquée dans Feinberg (2006) qui expliquait qu’il pouvait être économiquement juste à dire que la vie d’un trader de 25 ans “valait plus” qu’un pompier de 45 ans. Mais c’est surtout la variabilité entre les méthodes, que l’on retrouve également dans Hugonnier et al. (2018) qui surprend, et dérange, avec un facteur allant de 1 à 20 suivant la méthode utilisée. état de santé Quintile 0%-20% Quintile 40%-60% Quintile 80%-100% Statistique ‘fair’ 4 380 000 4 400 000 7 890 000 ‘very good’ 8 800 000 8 830 000 12 135 000 Gunpoint ‘fair’ 235 000 235 000 422 000 ‘very good’ 590 000 590 000 650 000 Capital humain 250 000 390 000 525 000 Tableau 2 : source Hugonnier et al. (2018) Le Tableau 2 reprend la valeur statistique (inspirée de Drèze 1962), celle basée sur des calculs de capital humain, ainsi qu’une « gunpoint value », en fonction du niveau de richesse de la personne qui décède (niveaux de quantiles) et de l’état de santé de la personne (avant son décès). Ces tableaux montrent à quel point il est difficile d’évaluer la vie de personnes impliquées dans un accident mortel. On essaye d’imaginer la valeur de la vie d’un « individu représentatif » (peut être en fonction de son état de santé, de son âge, de son revenu). Mais comment faire pour attribuer une valeur à une vie qui n’existe pas encore ? Car nombre de décisions prises aujourd’hui impactant aussi les « générations futures », c’est-à-dire des personnes qui aujourd’hui n’existent pas… Est-il possible de donner une valeur à la vie de ces personnes ? Car c’est normalement ce qu’il convient de faire si on veut mettre en place une politique visant à limiter le réchauffement climatique. References Abraham, С. & Thedié, J. 1960 Le prix d’une vie humaine dans les décisions économiques. Revue française de Recherche opérationnelle. 16 : 157-168 Banzhaf, Spenser H. 2014. Retrospectives: The Cold-War Origins of the Value of Statistical Life. Journal of Economic Perspective, 28 :4, 213-226. Benamouzig, Daniel. 2005. La Santé au miroir de l’Economie. Paris : PUF Biausque V. 2011, Valeur statistique de la vie humaine : une méta-analyse. OCDE Cavalin, C. 2016. « La valeur d’une vie statistique : histoire américaine, histoire de la pensée économique. » Incidence 12. Commissariat général à la stratégie et à la prospective 2013. Éléments pour une révision de la valeur de la vie humaine. http://www.strategie.gouv.fr/ Costa, Dora L. & Kahn Matthew E. 2004. Changes in the value of life, 1940-1980. Journal of Risk and Uncertainty, 29 :2, 159-180 Drèze, Jacques 1962. L’utilité sociale d’une vie humaine. Revue française de recherche opérationnelle 23 : 3 -28 Fabre, Françoise. 1970. « Une étude économique de la prévention et du dépistage précoce du cancer du col de l’utérus » Cahiers du Séminaire d’Econometrie 12, 121-143 Feinberg, Kenneth R. 2006. What Is Life Worth?: The Inside Story of the 9/11 Fund and Its Effort to Compensate the Victims of September 11th. Public Affairs. Johansson, Per-Olov, 2000. Is there a meaningful definition of the value of statistical life? Journal of Health Economics, 20, 131-139 Hugonnier, J., Pelgrin, F. & St-Amour, P. 2018. Valuing Life as an Asset, as a Statistic and at Gunpoint. Swiss Finance Institute Research Paper 18-27 Lery, Simon 2004. Arbitrages : le prix de la vie. Alternatives Economiques, 223. Mrozek, Janusz R. & Taylor, Laura O. 2002. What determines the value of life : a meta analysis. Journal of Policy Analysis and Management, 21 :2, 253–270 Schelling, T.C. 1968. ‘The life you save may be your own.’ In Problems in PublicExpenditure Analysis ed. Samuel B. Chase (Washington DC: Brookings Institution) 127–162 Ventura, Alba. 2019. 80km/h : « S’il s’agit de ne sauver qu’une vie, est-ce que ça ne vaut pas le coup ? », RTL, 29 janvier 2019. # A brief history of sports betting this article was originaly published – in French – in variance.eu A report by the American Gaming Association (May 2017) estimated that between$100 billion and $400 billion was bet each year on an estimated gross income of between$5 billion and $20 billion, just for sports betting. We will return here to a brief history of sports betting, emphasizing the concept of pari-mutuel betting. We will see, in a second article, the links of this principle with mathematical finance, and insurance. ## From games to sports Sports betting has been around for a long time, even if the origin of the first bet is impossible to date. We can think of the Greeks, inventors of the Olympic Games, where it was not uncommon for spectators to bet among themselves on the winners (Decker & Thuiller, 2004). Closer to home, as Georges Vigarello reminds us, “Under the Ancien Régime, gambling was the subject of a real passion. It takes the form of either betting games or prize games. The first, bets, are made between people from the same social world, between farmers or between nobles. The second, the prize games, take place during parish celebrations, and show different regional practices, with the struggle in Brittany, or the jump in Provence. We can also think of the confrontations between villages at the soule for example. Among the nobles, prize games are organized for special occasions (birth or wedding). These games were recreational and festive moments. It was not until the end of the 19th century that gambling became a sport, in line with the hygienist theories of the time. We can think of Baron Pierre de Coubertin, who wanted to “use all the means appropriate to develop our physical qualities to make them serve the collective good” through “sport”. We will find the Baron again in 1887 with the creation of the Union of French Societies of Athletic Sports, the official appearance of the notion of “sport”, replacing that of “game”, as Dietschy & Clastres (2006) points out, noting in passing that this Union is based on amateurism, in reaction against the companies of cycling (from 1860) and walking (around 1870) which resumed the traditions of price and betting games. Around 1890, this union, dedicated to athletics, opened up to other sports (rugby, field hockey, fencing, swimming) which were represented by specialized commissions. ## The first bookmakers and gambling A little earlier, during the Industrial Revolution, horse betting organised by bookmakers developed. These bets were popular in the United Kingdom in the 16th and 17th centuries, but remained reserved for the aristocracy and the landed gentry. And in reality, only horse owners were allowed to bet on the results of these private races, known as “matches”. One of his races, launched by the twelfth Earl of Derby (Edward Smith-Stanley) around 1870, also left its mark on sporting vocabulary. If these races were originally private, Charles II’s passion for these races made them more ambitious, attracting huge crowds, betting more and more important sums. Innkeepers and pub owners were then major promoters of these races, which encouraged owners to organize the races near their establishments. They then naturally became the first bookmakers, organizing the first steeple-chases, a form of race (first created in Ireland) where riders ran from one church tower to another by jumping everything in their path! In 1826, at the stables in Saint Alban, north of London, the idea of horses starting and finishing in the same place was launched, giving rise to modern racecourses. Betting was not yet regulated and betting on races was based on a credit system. And since gambling near a place where alcohol was available in large quantities can have dramatic consequences, the British government banned gambling in pubs, which led to the opening of betting shops, run by bookmakers, with the adoption of the Gambling Act in 1845. The bookmakers not only played the role of scribes, keeping track of transactions in registers, they also served as arbitrators in betting. The bookmaker has become the intermediary with whom to bet, he receives the bets, but does not bet against the player. The arbitrator does not only act at the end, in the event of a dispute, but above all to make the bet official. Indeed, cash bets were rare, and bookmakers decided whether the items bet had the same value and, if not, what the difference was. One of the players then adds money to a cap. Players put their hands in the hat and remove them, either to agree with the assessment or to indicate their disagreement. This is referred to as “hand in cap”, which refers to the amount of money needed to ensure a fair bet. The word “handicap” was then commonly used in horse betting (to designate disadvantaged participants at the start of a race) and then to have a medical connotation from 1950 onwards. Thereafter, bookmakers will not lack imagination, introducing cash bets, then offering fixed odds against each horse in a race. Parliament then went backwards with the Suppression of Betting Houses Act in 1853. Credit institutions and games of chance on racetracks were allowed. At the same time, in France, Léon Sari invented the “pari mutuel” in 1857 with Charles de Morny, owner of the Maisons-Laffitte racetracks (which became a building with stands in June 1878). Joseph Oller, who co-founded the Moulin-Rouge, is the concessionaire. As the Senate report on gambling in France reminds us, the law of June 2, 1891 legalizes betting on horse races and establishes the principle of mutualization. As we will see later, this principle means that bettors play against each other and share the winnings (once the legal levies provided for by law have been made for the benefit of the State and the institution of racing). In mathematical finance, we speak of “self-hedging strategy”. In March 1931, the PMU (“pari mutuel urbain”) was born, and it was not until 1985 that the “sports lotto” arrived. ## From horses to other sports The “pool” has long referred in England to a game of cards played for collective stakes, drawing its etymology from the French “hen”, or rather from the old French “hen”, referring to a young poultry (we will find the Latin word pulla, de pullus, the “young animal”), but also “booty” or “looting”. Here we find the idea of playing for money. This use can be traced back to 1870 (in the sense of “collective betting”) before becoming a pool during the First World War, and then to designate a group of people sharing skills. As early as 1920, the term “football pool” was coined, as recalled by Forrest (1999). In Liverpool, England, John Moores founded Littlewoods in 1923, a retail company, before launching mail order sales, while offering football bets. The most famous game was the “Treble Chance”, where players could choose to bet on 10, 11 or 12 football matches for the coming weekend. Anecdotally, as noted by Forrest & Pérez (20013), when a match could not take place (for example because of rain), a panel of experts appointed by Littlewoods had to model the match, and provide a forecast. After the Second World War, in Europe, we will see the arrival of so-called 1X2 formulas where the player must predict whether, in a set of 12 to 15 games, the home team will win (1), lose (2) or draw (X). It can be noted that these “football pools” could refer to any form of pari-mutuel betting, very strongly resembling a lotto. The main difference is that in the lottery, the draw is supposed to be a pure random process, unlike football matches. And for the players, the difference is significant! In the 1980s, Liverpool was one of the largest private companies in Europe. Before decreasing with the birth of online betting sites…. ## Internet and online betting Now, in addition to the betting companies that still exist in the United Kingdom, the strong point of bookmakers is their online presence. The first sites were created around 1995, for example Intertops, which was based on a law passed by the island nation of Antigua and Barbuda (an officially independent, Commonwealth member country) in 1994, granting licences to companies wishing to provide gambling services over the Internet (subsequently, they obtained licences from the Mohawk territory of Kahnawake in Quebec, or Malta). Betting on sports events has quickly become very popular. In 2000, Betfair was launched, and revolutionized the industry: Betfair itself did not take customer bets, but rather offered customers to place bets between them. These peer-to-peer betting was quickly very popular. In 2002, the first live betting was launched, offering bettors the opportunity to bet on a sporting event while it was taking place. Today, on lƒes larger sites, all kinds of sports are available, whether collective (football, basketball) or individual (tennis, boxing), with possibly a competition involving more than two players or teams (athletics, cycling). The player can choose an objective, which can be a final score (1X2 in football), a number of goals scored, etc., then he concludes the bet by choosing the amount he is willing to bet (the bet). On all sites, no less than 20,000 bets are possible every day. Decker, Wolfgang & Thuillier, Jean-Paul (2004). Le sport dans l’antiquité. Picard. Dietschy, Paul & Clastres, Patrick (2006). Sport, société et culture en France du XIXe siècle à nos jours. Hachette, Carré Histoire. Forrest, David (1999). The Past and Future of the British Football Pools. Journal of Gambling Studies, 15:2, 161-176. Forrest, David & Pérez, Levi (2013) The Football Pools in The Oxford Handbook of the Economics of Gambling, 147-162 Vigarello, Georges (2004) Le sport est-il encore un jeu ? Sciences Humaines, no 152. To be continued…. with a post on how bets, predictions and players’ beliefs are linked. # Les classes de risques vont-elles plus loin que les stéréotypes ? Mon court article est paru dans le dernier numéro de l’Actuariel, le magazine de l’Institut des Actuaires. # What it the interpretation of the diagonal for a ROC curve Last Friday, we discussed the use of ROC curves to describe the goodness of a classifier. I did say that I will post a brief paragraph on the interpretation of the diagonal. If you look around some say that it describes the “strategy of randomly guessing a class“, that it is obtained with “a diagnostic test that is no better than chance level“, even obtained by “making a prediction by tossing of an unbiased coin“. Let us get back to ROC curves to illustrate those points. Consider a very simple dataset with 10 observations (that is not linearly separable) x1 = c(.4,.55,.65,.9,.1,.35,.5,.15,.2,.85) x2 = c(.85,.95,.8,.87,.5,.55,.5,.2,.1,.3) y = c(1,1,1,1,1,0,0,1,0,0) df = data.frame(x1=x1,x2=x2,y=as.factor(y)) here we can check that, indeed, it is not separable plot(x1,x2,col=c("red","blue")[1+y],pch=19) Consider a logistic regression (the course is on linear models) reg = glm(y~x1+x2,data=df,family=binomial(link = "logit")) but any model here can be used… We can use our own function Y=df$y
S=predict(reg)
roc.curve=function(s,print=FALSE){ Ps=(S>=s)*1
FP=sum((Ps==1)*(Y==0))/sum(Y==0)
TP=sum((Ps==1)*(Y==1))/sum(Y==1)
if(print==TRUE){
print(table(Observed=Y,Predicted=Ps))
}
vect=c(FP,TP)
names(vect)=c("FPR","TPR")
return(vect)
}
or any R package actually
library(ROCR)
perf=performance(prediction(S,Y),"tpr","fpr")
We can plot the two simultaneously here
plot(performance(prediction(S,Y),"tpr","fpr")) V=Vectorize(roc.curve)(seq(-5,5,length=251))
points(V[1,],V[2,])
segments(0,0,1,1,col="light blue")
So our code works just fine, here. Let us consider various strategies that should lead us to the diagonal.
The first one is : everyone has the same probability (say 50%)
S=rep(.5,10)
plot(performance(prediction(S,Y),"tpr","fpr"))
V=Vectorize(roc.curve)(seq(0,1,length=251))
points(V[1,],V[2,])
Indeed, we have the diagonal. But to be honest, we have only two points here : $(0,0)$ and $(1,1)$. Claiming that we have a straight line is not very satisfying… Actually, note that we have this situation whatever the probability we choose
S=rep(.2,10)
plot(performance(prediction(S,Y),"tpr","fpr"))
V=Vectorize(roc.curve)(seq(0,1,length=251))
points(V[1,],V[2,])
We can try another strategy, like “making a prediction by tossing of an unbiased coin“. This is what we obtain
set.seed(1)
S=sample(0:1,size=10,replace=TRUE)
plot(performance(prediction(S,Y),"tpr","fpr"))
V=Vectorize(roc.curve)(seq(0,1,length=251))
points(V[1,],V[2,])
segments(0,0,1,1,col="light blue")
We can also try some sort of “random classifier”, where we choose the score randomly, say uniform on the unit interval
set.seed(1)
S=runif(10)
plot(performance(prediction(S,Y),"tpr","fpr"))
V=Vectorize(roc.curve)(seq(0,1,length=251))
points(V[1,],V[2,])
segments(0,0,1,1,col="light blue")
Let us try to go further on that one. For convenience, let us consider another function to plot the ROC curve
V=Vectorize(roc.curve)(seq(0,1,length=251))
roc_curve=Vectorize(function(x) max(V[2,which(V[1,]<=x)]))
We have the same line as previously
x=seq(0,1,by=.025)
y=roc_curve(x)
lines(x,y,type="s",col="red")
But now, consider many scoring strategies, all randomly chosen
MY=matrix(NA,500,length(y))
for(i in 1:500){
S=runif(10)
V=Vectorize(roc.curve)(seq(0,1,length=251))
MY[i,]=roc_curve(x)
}
plot(performance(prediction(S,df$y),"tpr","fpr"),col="white") for(i in 1:500){ lines(x,MY[i,],col=rgb(0,0,1,.3),type="s") } lines(c(0,x),c(0,apply(MY,2,mean)),col="red",type="s",lwd=3) segments(0,0,1,1,col="light blue") The red line is the average of all random classifiers. It is not a straight line, be we observe oscillations around the diagonal. Consider a dataset with more observations myocarde = read.table("http://freakonometrics.free.fr/myocarde.csv",head=TRUE, sep=";") myocarde$PRONO = (myocarde$PRONO=="SURVIE")*1 reg = glm(PRONO~.,data=myocarde,family=binomial(link = "logit")) Y=myocarde$PRONO
S=predict(reg)
plot(performance(prediction(S,Y),"tpr","fpr"))
V=Vectorize(roc.curve)(seq(-5,5,length=251))
points(V[1,],V[2,])
segments(0,0,1,1,col="light blue")
Here is a “random classifier” where we draw scores randomly on the unit interval
S=runif(nrow(myocarde)
plot(performance(prediction(S,Y),"tpr","fpr"))
V=Vectorize(roc.curve)(seq(-5,5,length=251))
points(V[1,],V[2,])
segments(0,0,1,1,col="light blue")
And if we do that 500 times, we obtain, on average
MY=matrix(NA,500,length(y))
for(i in 1:500){
S=runif(length(Y))
V=Vectorize(roc.curve)(seq(0,1,length=251))
MY[i,]=roc_curve(x)
}
plot(performance(prediction(S,Y),"tpr","fpr"),col="white")
for(i in 1:500){
lines(x,MY[i,],col=rgb(0,0,1,.3),type="s")
}
lines(c(0,x),c(0,apply(MY,2,mean)),col="red",type="s",lwd=3)
segments(0,0,1,1,col="light blue")
So, it looks like me might say that the diagonal is what we have, on average, when drawing randomly scores on the unit interval…
I did mention that an interesting visual tool could be related to the use of the Kolmogorov Smirnov statistic on classifiers. We can plot the two empirical cumulative distribution functions of the scores, given the response $Y$
score=data.frame(yobs=Y,
ypred=predict(reg,type="response"))
f0=c(0,sort(score$ypred[score$yobs==0]),1)
f1=c(0,sort(score$ypred[score$yobs==1]),1)
plot(f0,(0:(length(f0)-1))/(length(f0)-1),col="red",type="s",lwd=2,xlim=0:1)
lines(f1,(0:(length(f1)-1))/(length(f1)-1),col="blue",type="s",lwd=2)
we can also look at the distribution of the score, with the histogram (or density estimates)
S=score$ypred hist(S[Y==0],col=rgb(1,0,0,.2), probability=TRUE,breaks=(0:10)/10,border="white") hist(S[Y==1],col=rgb(0,0,1,.2), probability=TRUE,breaks=(0:10)/10,border="white",add=TRUE) lines(density(S[Y==0]),col="red",lwd=2,xlim=c(0,1)) lines(density(S[Y==1]),col="blue",lwd=2) The underlying idea is the following : we do have a “perfect classifier” (top left corner) is the supports of the scores do not overlap otherwise, we should have errors. That the case below we in 10% of the cases, we might have misclassification or even more missclassification, with overlapping supports Now, we have the diagonal when the two conditional distributions of the scores are identical Of course, that only valid when $n$ is very large, otherwise, it is only what we observe on average…. # Defense de doctorat d’Amadou Diogo Barry Ce jeudi matin, Amadou Diogo Barry défendra sa thèse de doctorat sur la régression expectile pour l’analyse de données longitudinales. # On the poor performance of classifiers in insurance models Each time we have a case study in my actuarial courses (with real data), students are surprised to have hard time getting a “good” model, and they are always surprised to have a low AUC, when trying to model the probability to claim a loss, to die, to fraud, etc. And each time, I keep saying, “yes, I know, and that’s what we expect because there a lot of ‘randomness’ in insurance”. To be more specific, I decided to run some simulations, and to compute AUCs to see what’s going on. And because I don’t want to waste time fitting models, we will assume that we have each time a perfect model. So I want to show that the upper bound of the AUC is actually quite low ! So it’s not a modeling issue, it is a fondamental issue in insurance ! By ‘perfect model’ I mean the following : $\Omega$ denotes the heterogeneity factor, because people are different. We would love to get $\mathbb{P}[Y=1|\Omega]$. Unfortunately, $\Omega$ is unobservable ! So we use covariates (like the age of the driver of the car in motor insurance, or of the policyholder in life insurance, etc). Thus, we have data $(y_i,\boldsymbol{x}_i)$‘s and we use them to train a model, in order to approximate $\mathbb{P}[Y=1|\boldsymbol{X}]$. And then, we check if our model is good (or not) using the ROC curve, obtained from confusion matrices, comparing $y_i$‘s and $\widehat{y}_i$‘s where $\widehat{y}_i=1$ when $\mathbb{P}[Y_i=1|\boldsymbol{x}_i]$ exceeds a given threshold. Here, I will not try to construct models. I will predict $\widehat{y}_i=1$ each time the true underlying probability $\mathbb{P}[Y_i=1|\omega_i]$ exceeds a threshold ! The point is that it’s possible to claim a loss ($y=1$) even if the probability is 3% (and most of the time $\widehat{y}=0$), and to not claim one ($y=0$) even if the probability is 97% (and most of the time $\widehat{y}=1$). That’s the idea with randomness, right ? So, here $p(\omega_1),\cdots,p(\omega_n)$ denote the probabilities to claim a loss, to die, to fraud, etc. There is heterogeneity here, and this heterogenity can be small, or large. Consider the graph below, to illustrate, In both cases, there is, on average, 25% chance to claim a loss. But on the left, there is more heterogeneity, more dispersion. To illustrate, I used the arrow, which is a classical 90% interval : 90% of the individuals have a probability to claim a loss in that interval. (here 10%-40%), 5% are below 10% (low risk), and 5% are above 40% (high risk). Later on, we will say that we have 25% on average, with a dispersion of 30% (40% minus 10%). On the right, it’s more 25% on average, with a dispersion of of 15%. What I call dispersion is the difference between the 95% and the 5% quantiles. Consider now some dataset, with Bernoulli variables $y$, drawn with those probabilities $p(\omega)$. Then, let us assume that we are able to get a perfect model : I do not estimate a model based on some covariates, here, I assume that I know perfectly the probability (which is true, because I did generate those data). More specifically, to generate a vector of probabilities, here I use a Beta distribution with a given mean, and a given variance (to capture the heterogeneity I mentioned above) a=m*(m*(1-m)/v-1) b=(1-m)*(m*(1-m)/v-1) p=rbeta(n,a,b) from those probabilities, I generate occurences of claims, or deaths, Y=rbinom(n,size = 1,prob = p) Then, I compute the AUC of my “perfect” model, auc.tmp=performance(prediction(p,Y),"auc") And then, I will generate many samples, to compute the average value of the AUC. And actually, we can do that for many values of the mean and the variance of the Beta distribution. Here is the code library(ROCR) n=1000 ns=200 ab_beta = function(m,inter){ a=uniroot(function(a) qbeta(.95,a,a/m-a)-qbeta(.05,a,a/m-a)-inter, interval=c(.0000001,1000000))$root b=a/m-a return(c(a,b)) } Sim_AUC_mean_inter=function(m=.5,i=.05){ V_auc=rep(NA,ns) b=-1 essai = try(ab<-ab_beta(m,i),TRUE) if(inherits(essai,what="try-error")) a=-1 if(!inherits(essai,what="try-error")){ a=ab[1] b=ab[2] } if((a>=0)&(b>=0)){ for(s in 1:ns){ p=rbeta(n,a,b) Y=rbinom(n,size = 1,prob = p) auc.tmp=performance(prediction(p,Y),"auc") V_auc[s]=as.numeric([email protected])} L=list(moy_beta=m, var_beat=v, q05=qbeta(.05,a,b), q95=qbeta(.95,a,b), moy_AUC=mean(V_auc), sd_AUC=sd(V_auc), q05_AUC=quantile(V_auc,.05), q95_AUC=quantile(V_auc,.95)) return(L)} if((a<0)|(b<0)){return(list(moy_AUC=NA))}} Vm=seq(.025,.975,by=.025) Vi=seq(.01,.5,by=.01) V=outer(X = Vm,Y = Vi, Vectorize(function(x,y) Sim_AUC_mean_inter(x,y)$moy_AUC)) library("RColorBrewer") image(Vm,Vi,V, xlab="Probability (Average)", ylab="Dispersion (Q95-Q5)", col= colorRampPalette(brewer.pal(n = 9, name = "YlGn"))(101)) contour(Vm,Vi,V,add=TRUE,lwd=2) On the x-axis, we have the average probability to claim a loss. Of course, there is a symmetry here. And on the y-axis, we have the dispersion : the lower, the less heterogeneity in the portfolio. For instance, with a 30% chance to claim a loss on average, and 20% dispersion (meaning that in the portfolio, 90% of the insured have between 20% and 40% chance to claim a loss, or 15% and 35% chance), we have on average a 60% AUC. With a perfect model ! So with only a few covariates, having 55% should be great ! My point here is that with a low dispersion, we cannot expect to have a great AUC (again, even with a perfect model). In motor insurance, from my experience, 90% of the insured are between 3% chance and 20% chance to claim a loss ! That’s less than 20% dispersion ! and in that case, even if the (average) probability is rather small, it is very difficult to expect an AUC above 60% or 65% ! # Variance decomposition and price segmentation in Insurance Today, I was giving a talk at the Economics department, and I got a very interesting question about some tables I keep showing to explain why insurance companies like segmentation. The tables illustrate three different case. Here, $S$ stands for the individual (random) loss. • the first one is the case where the premium asked is the same for all the insured – i.e. the pure premium $\mathbb{E}[S]$ As explain, the loss is here on an individual basis, so, per policy, the insurer faces the (random) loss $S-\mathbb{E}[S]$, which is, on average, null. That’s the second line. For the last line, I keep saying that we look at the overall loss of the insurer, but that’s not correct. Here, with a factor $n$, we would have the variance of the total loss for the insurance company. We just removed the $n$ factor in the table • then, we have perfectly observable heterogeneity : insured have a risk factor $\Omega$, obervable, and in that case, the ‘pure’ premium is $\mathbb{E}[S|\Omega]$ That’s what we have below. Here again, on average, the insured should have a null profit. And the total variance (which was $\text{Var}[S]$ in our previous example) is now splitted in two parts (that’s basically Pythagoras theorem). The interpreration is the following And then, I usually mention the third and last case, more realistic • the risk factor $\Omega$ is not obervable, but segmentation is still possible using some proxy of the risk factor, obtained using some covariates, and the ‘pure’ premium is $\mathbb{E}[S|\boldsymbol{X}]$ And here also, there is a nice interpretation, because of the variance decomposition : there is one part that we observed previously, with some ‘perfect pricing’ and an additional part (that is positive) that is related to the fact that the covariates are just a proxy of the risk factor…. The term on the left is then a lower bound, obtained if actually, using our covariate, available for the pricing, we can get the risk factor. That was my story, but the fact that $n$ (the portfolio size) was not mentioned in the tables was a bit confusing… So I decided to create some graphs to illustrate those three cases • same premium for everyone Consider some simple simulations. On the graph on the left, we have on the x-axis the risk factor, and on the y-axis, the loss (going roughly from 0 to 20). The pure premium is the average of those losses. Here, it’s 10. That’s the plain red line (on the left). In the middle, the y-axis is the insured profit/loss per policy. Someone with a loss close to 0 means a gain of 10, someone with a loss close to 20 means a loss of 10. On average, there is no profit (that’s the plain line). And then, on the right, we have the distribution of the profit/loss (per contract). Again, on average it’s 0, with some variance, • premium based on covariates Consider here is simple covariate $x$ : assume here that’s we’ve been able to create a binary variable, that can distinguish the low risks and the high risks. Here, there are two levels for the premium. The low premium is close to 6, and the high one is close to 14. That’s again the graph on the left Then we have the profit/loss per policy for the insured, in the middle. Here, when the loss was close to 0, the gain is smaller : it is 6 (while it was 10 before). When it was close to 10, previously, it meant a 0 profit, but now it’s either a loss of 4, or a gain of 4. The profit/loss distribution is now on the right. There is less dispersion, and less variance. That the decrease of variance we’ve discussed before. To summarize, segmentation does reduce the variability of the result for the insurance company. That’s what we observe on the right. • premium based on the risk factor Assume now that $\Omega$ is observable. And that we use it for our pricing. The premium is now continuous, and it is the red line, on the left. The profit/loss (in the middle) is the difference between the loss, and its expected value (conditional on the risk factor). And on the right, we have the distribution. As expected, there is much less variability on the profit/loss distribution of the insurance company in that case. And actually, that’s a lower bound for the variance of result of the insurance company… I hope that the graph clarify what’s going on here… # Variance of the slope in a regression model In my “applied linear models” exam, there was a tricky question (it was a multiple choice, so no details were asked). I was simply asking if the following statement was valid, or not Consider a linear regression with one single covariate, $y=\beta_0+\beta_1x_1+\varepsilon$ and the least-square estimates. The variance of the slope is $\text{Var}[\widehat{\beta}_1]$ Do we decrease this variance if we add one variable, and consider $y=\beta_0+\beta_1x_1+\beta_2x_2+\varepsilon$ ? For the exam, the expected answer was simply “no”. In a nutshell, there are two cases where we should expect different changes, • if $x_1$ and $x_2$ are highly correlated, then we should expect the variance to increase • if $x_1$ and $x_2$ are not correlated, then we should expect the variance to decrease We did briefly observed (and discussed) those points on examples during the lecture… but I wanted to go a bit further, since I couldn’t find any analytical results. Let us generate a model $y=\beta_0+\beta_1x_1+\beta_2x_2+\varepsilon$, and then compare the variance $\text{Var}[\widehat{\beta}_1]$ on the two fitted modes, depending on the correlation between $x_1$ and $x_2$ library(mnormt) n=200 s=function(r=0){ S=matrix(c(1,r,r,1),2,2) X=rmnorm(n,c(0,0),S) B=data.frame(y=-2+X[,1]+X[,2]+rnorm(n)/2, x1=X[,1], x2=X[,2]) reg12=lm(y~x1+x2,data=B) reg1=lm(y~x1,data=B) k=summary(reg12)$coefficients[2,2]/summary(reg1)$coefficients[2,2] k} Let us generate 500 samples for each value of the correlation, from -0.9 to _0.9 M=NULL for(r in ((-9):9)/10) M=cbind(M,Vectorize(s)(rep(r,500))) and let us plot the ratio of the two variances plot(0:1,0:1,xlim=c(-1,1),ylim=c(0,2),col="white") for(i in 1:19) points(rep((((-9):9)/10)[i],500),M[,i],col="light blue") VM=apply(M,2,mean) lines((((-9):9)/10),VM,col="red",lwd=2) abline(h=1,lty=2) If the ratio exceeds 1, the variance increases when adding a covariate. Indeed, here, when the two variables are independent, the variance is divided by two. But when covariates are highly correlated, the variance is multiplied by two… Now, what if, actually, $x_2$ is not a real explanatory variable : the true model we generate is $y=\beta_0+\beta_1x_1+\varepsilon$. In that case, s=function(r=0){ S=matrix(c(1,r,r,1),2,2) X=rmnorm(n,c(0,0),S) B=data.frame(y=-2+X[,1]+rnorm(n)/2, x1=X[,1], x2=X[,2]) reg12=lm(y~x1+x2,data=B) reg1=lm(y~x1,data=B) k=summary(reg12)$coefficients[2,2]/summary(reg1)\$coefficients[2,2] k}
we get our samples as previously
M=NULL for(r in ((-9):9)/10) M=cbind(M,Vectorize(s)(rep(r,500)))
and we plot those ratios
plot(0:1,0:1,xlim=c(-1,1),ylim=c(0,2),col="white") for(i in 1:19) points(rep((((-9):9)/10)[i],500),M[,i],col="light blue") VM=apply(M,2,mean) lines((((-9):9)/10),VM,col="red",lwd=2) abline(h=1,lty=2)
In the case we add a useless variable $x_2$, whatever the correlation with $x_1$, it will always, on average, increase the variance of $\widehat{\beta}_1$.
# Talk at the Economics Seminar at UQAM
Wednesday, at lunch time, I will give a talk on insurance pricing at the (internal) economics seminar, at UQAM. Slides are now online.
In May, I will also give a seminar on the same topic at the Computational Science seminar…
# Annual UCSB InsurTech Summit
Just a quick post to mention that an Insurtech Summit will be organized in May 2019, on Friday 3rd, by Mike Ludkovski, and I will be there, with Francois Millard (Vitality Group), Adam Tashman (Carpe Data, Santa Barbara), Emil Valdez (University of Connecticut), and Howard Zail (Elucidor, LLC, New York City). That will be nice… I will actually also give a talk on the Monday before at the actuarial seminar !
OpenEdition
|
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https://infoscience.epfl.ch/record/262658
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## Oxygen diffusion through air–water free surfaces in a pump–turbine operating in condenser mode
The present research aims at understanding the mass transfer of air into water in a reversible pump turbine operating in condenser mode. In particular, the diffusion of oxygen through the water free-surface both in the vaneless gap between the impeller blades and the closed guide vanes and in the cone of the draft tube is investigated. A theoretical framework is carried out to compute the diffusion equation describing the oxygen diffusion process in the investigated machine. Oxygen concentration measurements together with temperature and wall pressure measurements are performed to validate the theoretical model of the mass transfer of oxygen in the water volume and to evaluate the influence of the densimetric Froude number, of the gauge pressure and of the cooling discharge on the diffusion process. Moreover, the analytical solution of the diffusion equation applied to both the free surfaces in the vaneless gap and in the cone of the draft tube allows computing the global diffusion coefficient for each air–water free- surface. The results show that the oxygen concentrations computed by the analytical model of the oxygen diffusion are in agreement with the measurements. The dependency of the oxygen concentration in water on the densimetric Froude number, on the gauge pressure and on the water-cooling discharge is also observed. The computed global diffusion coefficients are mainly dependent on the densimetric Froude number in the vaneless gap and in the cone of the draft tube. Finally, the results achieved allow estimating the air losses correlated to the oxygen diffusion causing the increase of the water level in the cone of the draft tube.
Published in:
International Journal of Multiphase Flow, 112, 183-192
Year:
Mar 01 2019
Keywords:
Other identifiers:
Laboratories:
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https://tex.stackexchange.com/questions/504041/is-this-possible-to-fix-the-numbers-always-in-roman-using-listing/504416
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# Is this possible to fix the numbers always in roman using listing
My tags are follows:
\documentclass{book}
\usepackage{xcolor}
\usepackage{textcomp,listings}%
\lstnewenvironment{python}[1][]{%
\lstset{%
mathescape=false,%
language=python,%
basicstyle=\ttfamily\normalsize,%
otherkeywords={*,\{, \} },%
keywordstyle=\color{black},%
stringstyle=\color{black},%
showstringspaces=false,%
emph={class, pass, in, for, while, if, is, elif, else, not, and, or,%
def, print, exec, break, continue, return},%
emphstyle=\color{black}\bfseries,%
emph={[3]True, False, None, self},%
emphstyle=[2]\color{black!10},%
emph={[3]from, import, as},%
emphstyle=[3]\color{black},%
upquote=true,%
morecomment=[s]{"""}{"""},%
aboveskip=12pt,belowskip=12pt,xleftmargin=-2pt,xrightmargin=3pt,framexleftmargin=20pt,framextopmargin=1pt,%
rulesepcolor=\color{gray},#1%
}}{}%
\begin{document}
\begin{python}
In [7]: np.searchsorted(X, 0.5)
Out[7]: 4998210 # This is 1 for test 1000
\end{python}
\begin{python}
In [7]: np.searchsorted(X, 0.5) # left edge 1234567890
from scipy import stats
dist stats.uniform (0, 2) # left edge 0, width 2
\end{python}
\end{document}
It is working fine without issues. Please confirm that I need the arabic numerals (i.e., 0 to 9) should be in roman always, refer the screen shot:
• Do you want the numbers to be in roman font only in comments or everywhere? – siracusa Aug 16 at 5:06
• @siracusa Thanks for your attention. Other places it comes correctly (in roman font), but in the commented text it comes in italic, but I need those to be in roman – MadyYuvi Aug 16 at 5:39
Here's a solution that makes use of the general number highlighting approach presented in Listings: color numbers only out of keywords.
We need to make some changes to the OutputOther hook from that solution, because in this case you want to override the default style no matter whether you are in a comment or not. The new hook looks like:
\lst@AddToHook{OutputOther}{%
\lst@ifparsenumbers
\expandafter\@hook@ifnumber\the\lst@token\@end {%
\let\orig@thestyle=\lst@thestyle
}{}%
\fi
}
Also to your \lstset command the following lines have to be added:
parsenumbers=true,
Wherever a number is then parsed by listings in the input, the numbersstyle is added to the currently active style.
Full example code:
\documentclass{book}
\usepackage{xcolor}
\usepackage{textcomp,listings}%
\makeatletter
%%% Copied from https://tex.stackexchange.com/a/500690/23765
% Some conditional tests
\def\@genericif#1{#1\expandafter\@firstoftwo\else\expandafter\@secondoftwo\fi}
\def\@ifdigit#1{\@genericif{\ifnum1<1\noexpand#1\relax}}
\def\@ifempty#1{\@genericif{\if\relax\detokenize{#1}\relax}}
% The main parsing macros
\def\parse@num#1{%
\@ifempty{#1}%
{\parse@num@false}%
{\@genericif{\parsesign}%
{\parse@num@sign#1{}\@end}%
{\parse@num@dig#1{}\@end}%
}%
}
% Parse sign
\def\parse@num@sign#1#2\@end{%
\@genericif{\ifx\parse@num@minus#1}%
{\@ifempty{#2}{\parse@num@false}{\parse@num@dig#2\@end}}%
{\@genericif{\ifx\parse@num@plus#1}%
{\@ifempty{#2}{\parse@num@false}{\parse@num@dig#2\@end}}%
{\parse@num@dig#1#2\@end}%
}%
}
% Parse first digit
\def\parse@num@dig#1#2\@end{%
\@ifdigit{#1}%
{\@ifempty{#2}{\parse@num@true}{\parse@num@digs#2\@end}}%
{\parse@num@false}%
}
% Parse optional following digits
\def\parse@num@digs#1#2\@end{%
\@ifdigit{#1}{%
\@ifempty{#2}%
{\parse@num@true}%
{\parse@num@digs#2\@end}%
}{%
\@genericif{\parsefloat}{%
\@genericif{\ifx\parse@num@point#1}%
{\@ifempty{#2}{\parse@num@false}{\parse@num@decs#2\@end}}%
{\parse@num@false}%
}{\parse@num@false}%
}%
}
% Parse decimal places
\def\parse@num@decs#1#2\@end{%
\@ifdigit{#1}{%
\@ifempty{#2}%
{\parse@num@true}%
{\parse@num@decs#2\@end}%
}{\parse@num@false}%
}
% User interface
\newcommand\ifnumber[4][]{%
\begingroup
\let\parsesign=\iftrue
\let\parsefloat=\iftrue
\let\parse@num@minus=-%
\let\parse@num@plus=+%
\let\parse@num@point=.%
#1%
\def\parse@num@true{\endgroup#3}%
\def\parse@num@false{\endgroup#4}%
\parse@num{#2}%
}
%%% Additions to the listings package
\lst@Key{parsenumbers}{false}[t]{\lstKV@SetIf{#1}\lst@ifparsenumbers}
\lst@ifparsenumbers
\expandafter\@hook@ifnumber\the\lst@token\@end {%
\let\orig@thestyle=\lst@thestyle
}{}%
\fi
}
\def\@hook@ifnumber#1#2\@end{%
\@genericif{\ifx\lst@nolig#1}%
{\@hook@ifnumber@{#2}}%
{\@hook@ifnumber@{#1#2}}%
}
\def\@hook@ifnumber@{%
\ifnumber[\expandafter\let\expandafter\parse@num@minus\csname lst@um-\endcsname]%
}
\makeatother
\lstnewenvironment{python}[1][]{%
\lstset{%
mathescape=false,%
language=python,%
basicstyle=\ttfamily\normalsize,%
otherkeywords={*,\{, \} },%
keywordstyle=\color{black},%
stringstyle=\color{black},%
showstringspaces=false,%
emph={class, pass, in, for, while, if, is, elif, else, not, and, or,%
def, print, exec, break, continue, return},%
emphstyle=\color{black}\bfseries,%
emph={[3]True, False, None, self},%
emphstyle=[2]\color{black!10},%
emph={[3]from, import, as},%
emphstyle=[3]\color{black},%
upquote=true,%
morecomment=[s]{"""}{"""},%
aboveskip=12pt,belowskip=12pt,xleftmargin=-2pt,xrightmargin=3pt,framexleftmargin=20pt,framextopmargin=1pt,%
rulesepcolor=\color{gray},#1,
parsenumbers=true,
}}{}%
\begin{document}
\begin{python}
In [7]: np.searchsorted(X, 0.5)
Out[7]: 4998210 # This is 1 for test 1000
"""
Some text 1234
"""
\end{python}
\end{document}
EDIT: The problem of the 0 not showing up in upright font is due to the fact that listings parses 0 and , as one unit (as both have codes digit or other). The OutputOther hook then tries to parse 0, as a number which fails and thus doesn't give the expected font.
As a workaround you can add the following line to the \lstset command:
literate={,}{{\char\,}}{1}
which outputs
This makes the parser break before it reads the comma. In this special case there should be no side-effects, because commas shouldn't be part of keywords or other special syntax elements. Unfortunately, listings makes it hard to add the processing of new syntax elements, so working around one problem here often raises another one there.
• Wow, such a great reply...much thankful to you.... – MadyYuvi Aug 16 at 9:02
• If I try second python text, \begin{python} In [7]: np.searchsorted(X, 0.5) # left edge 1234567890 from scipy import stats dist stats.uniform (0, 2) # left edge 0, width 2 \end{python}` 0 and 2 comes in italic which comes at the last line, any thing mistake I did? Please advise... – MadyYuvi Aug 16 at 10:11
• I've updated my question too... – MadyYuvi Aug 16 at 10:14
• Just now realised that comma between characters affected this error, is this possible to fix? advise please... – MadyYuvi Aug 16 at 10:17
• @MadyYuvi Please see the update – siracusa Aug 16 at 10:36
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http://physics.stackexchange.com/questions/47798/parallel-universe-and-infinite-monkey-theorem
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# Parallel universe and Infinite monkey theorem [closed]
Is the Infinite monkey theorem helpful for determining the existence of the very same our universe somewhere else?
-
## closed as not constructive by Sklivvz♦, Manishearth♦Dec 29 '12 at 21:27
As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.
I've once read a popular article wherein serious cosmologists were applying this theorem (although the name was not explicitely mentioned) to investigate if things we can observe inside our cosmic horizon could be repeated in our universe outside the cosmic horizon. I think when considering the question in such a context, it is legitimate and does not need to be closed. But maybe @Inquisitive you could clarify the context a little bit? – Dilaton Dec 29 '12 at 11:35
This is rather open-ended in its current form. (as well as being about fictional physics, and not really clear) Please see the don't ask section of the faq. – Manishearth Dec 29 '12 at 21:27
The basic idea is that if you take some system (e.g. your mother in law) containing $n$ Planck volumes then the maximum number of configurations of this system is 2$^n$. So you need to look at about 2$^n$ such volumes to stand a reasonable chance of finding a duplicate of your mother in law. This is the origin of claims that an exact copy of the Earth must exist if you take a big enough region of the universe. Whether such claims have any physical validity is open to debate.
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|
http://pubman.mpdl.mpg.de/pubman/faces/viewItemOverviewPage.jsp?itemId=escidoc:2083328
|
de.mpg.escidoc.pubman.appbase.FacesBean
English
# Item
ITEM ACTIONSEXPORT
Released
Journal Article
#### Measurement of the Ξ-b and Ω-b baryon lifetimes
##### MPS-Authors
http://pubman.mpdl.mpg.de/cone/persons/resource/persons30313
Blouw, J.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
http://pubman.mpdl.mpg.de/cone/persons/resource/persons30339
Britsch, M.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
http://pubman.mpdl.mpg.de/cone/persons/resource/persons37734
Fontana, M.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
http://pubman.mpdl.mpg.de/cone/persons/resource/persons37740
Popov, D.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
http://pubman.mpdl.mpg.de/cone/persons/resource/persons30992
Schmelling, M.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
http://pubman.mpdl.mpg.de/cone/persons/resource/persons37744
Volyanskyy, D.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
http://pubman.mpdl.mpg.de/cone/persons/resource/persons31150
Voss, H.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
http://pubman.mpdl.mpg.de/cone/persons/resource/persons31206
Zavertyaev, M.
Division Prof. Dr. Werner Hofmann, MPI for Nuclear Physics, Max Planck Society;
##### Fulltext (public)
1405.1543.pdf
(Preprint), 562KB
##### Supplementary Material (public)
There is no public supplementary material available
##### Citation
LHCb Collaboration, Aaij, R., Adeva, B., Adinolfi, M., Affolder, A., Ajaltouni, Z., et al. (2014). Measurement of the Ξ-b and Ω-b baryon lifetimes. Physics Letters B, 736, 154-162. doi:10.1016/j.physletb.2014.06.064.
Cite as: http://hdl.handle.net/11858/00-001M-0000-0024-906C-5
##### Abstract
Using a data sample of pp collisions corresponding to an integrated luminosity of $3~ \rm fb^{-1}$, the $\Xi_b^-$ and $\Omega_b^-$ baryons are reconstructed in the $\Xi_b^- \rightarrow J/\psi \Xi^-$ and $\Omega_b^- \rightarrow J/\psi \Omega^-$ decay modes and their lifetimes measured to be $\tau (\Xi_b^-) = 1.55\, ^{+0.10}_{-0.09}~{\rm(stat)} \pm 0.03\,{\rm(syst)}$ ps, $\tau (\Omega_b^-) = 1.54\, ^{+0.26}_{-0.21}~{\rm(stat)} \pm 0.05\,{\rm(syst)}$ ps. These are the most precise determinations to date. Both measurements are in good agreement with previous experimental results and with theoretical predictions.
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http://swmath.org/software/7145
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# occam-pi
Communicating mobile processes. Introducing occam-pi. This paper introduces occam-$pi$, an efficient and safe binding of key elements from Hoare’s CSP and Milner’s $pi$-calculus into a programming language of industrial strength. A brief overview of classical occam is presented, before focussing on the extensions providing data, channel and process mobility. Some implementation details are given, along with current benchmark results. Application techniques exploiting mobile processes for the direct modelling of large-scale natural systems are outlined, including the modelling of locality (so that free-ranging processes can locate each other). Run-time overheads are sufficiently low so that systems comprising millions of dynamically assembling and communicating processes are practical on modest processor resources. The ideas and technology will scale further to address larger systems of arbitrary complexity, distributed over multiple processors with no semantic discontinuity. Semantic design, comprehension and analysis are made possible through a natural structuring of systems into multiple levels of network and the compositionality of the underlying algebra.
## References in zbMATH (referenced in 3 articles , 1 standard article )
Showing results 1 to 3 of 3.
Sorted by year (citations)
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http://mathhelpforum.com/calculus/207449-need-help-integration-questions-fractions-e.html
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# Math Help - Need help with integration (questions with fractions, and e)
1. ## Need help with integration (questions with fractions, and e)
Hi, I can do basic integration but on stuck on a few questions, with fractions and e. If you show me how to do these two, I'm sure I could do the rest.
1. dx
2. dx
Thanks, really appreciate any input.
2. ## Re: Need help with integration (questions with fractions, and e)
Hello
1. $\mathrm{\displaystyle\int\dfrac{1}{4x+1}dx=\dfrac{ \ln(4x+1)}{4}+C}$
$\boxed{\mathrm{\displaystyle\int\dfrac{dt}{t}=\ln t+C}}$
2. $\mathrm{\displaystyle\int4e^{1-4x}=-e^{1-4x}+C}$
$\boxed{\mathrm{\displaystyle\int e^t=e^t+C}}$
Greetings
3. ## Re: Need help with integration (questions with fractions, and e)
Originally Posted by darthjavier
Hello
1. $\mathrm{\displaystyle\int\dfrac{1}{4x+1}dx=\dfrac{ \ln(4x+1)}{4}+C}$
$\boxed{\mathrm{\displaystyle\int\dfrac{dt}{t}=\ln t+C}}$
2. $\mathrm{\displaystyle\int4e^{1-4x}=-e^{1-4x}+C}$
$\boxed{\mathrm{\displaystyle\int e^t=e^t+C}}$
Greetings
No, the first is incorrect. It should be \displaystyle \begin{align*} \int{\frac{1}{4x + 1}\,dx} = \frac{\ln{|4x + 1|}}{4} + C \end{align*} since \displaystyle \begin{align*} \int{\frac{1}{t}\,dt} = \ln{|t|} + C \end{align*}.
4. ## Re: Need help with integration (questions with fractions, and e)
Originally Posted by Prove It
No, the first is incorrect. It should be \displaystyle \begin{align*} \int{\frac{1}{4x + 1}\,dx} = \frac{\ln{|4x + 1|}}{4} + C \end{align*} since \displaystyle \begin{align*} \int{\frac{1}{t}\,dt} = \ln{|t|} + C \end{align*}.
Oops I'm sorry :P
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http://tex.stackexchange.com/questions/70516/how-to-compile-acm-sig-alternative-template-successfully?answertab=active
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# How to compile ACM sig-alternative template successfully?
I am new to texlive. After I downloaded the files from ACM website:
``````Alternate ACM LaTeX2e Style File V2.5 (MAY 2012 CLS)
Alternate ACM LaTeX2e Sample File V2.0 (MAY 2012 LaTeX)
ACM LaTeX2e Sample BIB File
Graphic #1 (EPS)
Graphic #2 (EPS)
Graphic #3 (PS)
``````
I used command `pdflatex sig-alternate.tex`. I got an error as below:
``````! LaTeX Error: Unknown graphics extension: .ps.
``````
While if I use `latex sig-alternate.tex`. The compilation can be done, but with some warnings like:
``````[3]
No file sig-alternate.bbl.
``````
I have the file `sigproc.bib`.
And I couldn't open the generated `sig-alternate.dvi` with preview. After `dvipdf sig-alternate.dvi`, I found the references section is missing.
-
It seems the `sigproc.bib` file needs to be compiled between two runs of the `latex`, using the following command:
``````latex sig-alternate
Note that neither command `bibtex sigproc.bib` or `bibtex sig-alternate.tex` would work.
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http://openstudy.com/updates/510d76e0e4b09cf125bcad12
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## A community for students. Sign up today
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## anonymous 3 years ago How do you solve for 'x' in this specific equation? (equation in comments) Delete Cancel Submit
• This Question is Closed
1. anonymous
• 3 years ago
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$3=\frac{ 175 }{ 3 }x + -55 \frac{ 175 }{ 3 }$
2. blurbendy
• 3 years ago
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Start by multiplying 55 and 175 together 3 = 175/3x - 9625/3 Add the fractions over a common denominator as a single fraction 175/3x - 9625 /3 = (175x - 9625) / (3) Multiply both sides by a constant (3) 175x - 9625 = 9 Can you solve from here?
3. anonymous
• 3 years ago
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My answer was x = 55, is that correct?
4. anonymous
• 3 years ago
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55.05142857
5. anonymous
• 3 years ago
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Yes, that's what I had gotten (55.05).
6. anonymous
• 3 years ago
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Thank you!
7. blurbendy
• 3 years ago
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cool
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https://www.enotes.com/homework-help/monica-told-her-mother-to-let-i-be-the-incenter-2862244
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Monica told her mother to let I be the incenter of the inscribed circle of triangle ABC. Prove that AI/ID = (b+c/a)
I is the incenter of the circle , hence it is the meeting point of the bisectors of <A,
We denote sides AB , BC and AC as c, a and b respectively.
To Prove : AI/ID= (b + c)/a
To prove this we use Angle bisector theorem which states that , in a triangle the bisector of an angle divides the opposite side in the ratio of the sides containing it.
In triangle ABD, BI bisects <B,
hence AB/BD= AI/ID
c/ BD = AI/ ID------(1) (by Angle bisector theorem )
In triangle ACD, CI is bisector of <C
AC/CD = AI/ID
b/CD= AI/ID-------(2)
From equations (1) and (2) c/BD = b/CD
CD/BD =b/c
Adding 1 to both sides , CD/BD +1 = b/c +1
(CD+BD)/BD = ( b + c )/c
BC/BD = (b +c)/c
a/BD = (b +c)/c
or c/BD = (b +c)/a, from equation (1 ) we have c/BD= AI/ID
AI/ID = (b +c)/a
Hence proved
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http://mathoverflow.net/questions/164798/the-k1-local-spanier-whitehead-dual-of-ko
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# The K(1)-local Spanier-Whitehead dual of KO
Let $D_1KO$ be the $K(1)$-local Spanier-Whitehead dual of $KO$, i.e. the spectrum $$D_1KO = F(KO,L_{K(1)}S^0).$$
I am interested in what this is. In fact I know that $D_1KO = \Sigma^{-1} KO$. One way to see this is to use the fact that the Gross-Hopkins dual $I_1 = \Sigma^2 P$ for a spectrum $P$ such that $P \wedge KO \simeq \Sigma^4 KO$, along with the equivalence $$I_1KO = D_1KO \wedge I_1.$$
Here is a claimed direct proof, due to Hahn and Mitchell (see Lemma 8.16).
Start with the cofiber sequence $$\Sigma^{-1} KO \to \Sigma^{-1} KO \xrightarrow{\delta} L_{K(1)}S^0,$$ and define a map $$\phi:\Sigma^{-1}KO \to F(KO,\Sigma^{-1}KO) \xrightarrow{\delta_*} F(KO,L_{K(1)}S^0),$$ where the first map is the adjoint to the (desuspension) of the multiplication map. The claim is that $\phi$ induces a weak equivalence on homotopy groups.
How does one show this? Namely, how do we compute $\pi_*F(KO,L_{K(1)}S^0)$?
-
If everything is completed at an odd prime $p$, and $k$ is a topological generator of $\mathbb{Z}_p^\times$, then $L_{K(1)}S$ is the fibre of $\psi^k-1\colon KU\to KU$. This means that $F(KU,L_{K(1)}S)$ is the fibre of the corresponding self-map $(\psi^k-1)_*$ of $F(KU,KU)$, which is not too hard to understand. A slight adjustment of this should work for $KO$ at $p=2$, but I forget what is the best way to organise it.
Thanks Neil! I was being a bit lazy with my notation - everything is really at the prime 2. In this case $F(KO,L_{K(1)}S^0)$ is the fibre of the self-map $(\psi^3-1)_\ast$ of $F(KO,KO)$ so I guess this is the map to understand? – Drew Heard Apr 30 '14 at 9:36
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https://hoverbear.org/blog/the-menagerie-of-badssl/
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# The Menagerie of Badssl
Late last year I was given an opporunity to participate in the Mozilla Winter of Security 2016! I'm happy to report it was, and still is, super cool. Plans diverted significantly at the very start of the project as it was discovered that the "menagerie" of certificates we wanted to build already existed.
What joy! In order to avoid any "not-invented-here" syndrome problems we pivoted, like a failing startup, and I moved to become a contributor to BadSSL. One of my mentors, April King, happened to already be a contributor to BadSSL and helped me get acquainted with the repository and the maintainer, Lucas Garron.
I was glad to discover that BadSSL is a Jekyll site. I've used Jekyll a number of times for different tasks and really enjoy working with the program. BadSSL is deployed on the Google Cloud Platform and is primarily powered via extensive nginx configurations.
## Superfish and Dell Fumble
In a couple spectacular fumbles by Dell and Lenovo we got a couple really interesting new specimens. Lenovo's bundled adware 'Superfish' CA and Dell's Curious Customer Service CA were discovered and compromised. We subsequently added https://superfish.badssl.com/, https://edellroot.badssl.com/, and https://dsdtestprovider.badssl.com/ so that potentially affected users could easily test their systems.
## The Spider's Web
One of the problems we identified with the current version of BadSSL was the tangle of files one needs to create or manipulate to generate a new subdomain. As an example, adding the above mentioned 3 subdomains required changing over 18 files. After doing some research I discovered that we could harness the power of Jekyll's _data files to our advantage. I have a Pull Request I've been trying to land that will greatly simplify this process and permit further automation.
I really enjoy working with these types of templating and data transformation problems. I've been exploring using Jekyll Generators automate the creation of some remaining crud files however I haven't made any solid progress on that yet.
## A Whale of a Time
Those gosh darn whale containers are really hard to set up sometimes. BadSSL had a Dockerfile however it wasn't harnessing all of the features it could have. For example Jekyll was called outside of the container, and required the user to have installed it already. April and I spent many hours on IRC coaxing around various steps of the build system to find a happy medium between speed and heft. I think moving forward using a container might be the right choice for production as well.
I'd like to set up a shared-volume based command for filesystem watching, however this will likely involve figuring out how to hook onto post-builds in Jekyll to fire Nginx restarts. Then we could use something like jekyll serve inside the container while updating the development copy of the website from outside the container.
## Weaving a Tale
Without an explanation of what's being tested it's hard to argue that having tests are worthwhile! BadSSL (until the data branch merges) has no comprehensive descriptions about what different certificates represent contextually. The data branch, and soon production, features a full set of descriptions embedded into each page as well as on the index.
One thing I learned all too well while compiling this information is that security is very complicated. There are so many varieties of cipher suites supporting (or not) many different browsers, operating systems, esoteric configurations, and eras of computing. It makes me worry when I see crypto libraries that advertise configurability these days. I'd much rather see simple and foolproof.
## Smooth Like Butter
Descriptions for each specimen of our little menagerie was great, but it made the front page mind-blowingly wordy. So what's a bear to do but resort to tooltips? After looking at various options it was kind of conclusive that most tooltip libraries wouldn't fit our desired use case. We wanted tooltips that wouldn't be invasive, that could include HTML like links, and worked in situations where the client had Javascript disabled.
So instead I wrote up some CSS animations to handle the task. You can see a demo below:
Hover your mouse over me!
I'm a test description! Typically this is a sentence or two, so it tends to need two lines.
Hover your mouse over me!
I'm a test description! Typically this is a sentence or two, so it tends to need two lines.
Hover your mouse over me!
I'm a test description! Typically this is a sentence or two, so it tends to need two lines.
## A Big Congratulations!
As you may have noticed, some of these tasks are yet to be complete or merged, and that's because April had a fantastical life event happen! Her and her partner welcome a new life recently. I'm very happy for both of them and encourage her to take her time to adjust to these new changes. We can continue our work together when she is ready.
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http://cmdlinetips.com/2016/01/bash-tip-search-through-history-using-the-up-and-down-arrows/
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# Bash tip: Search through history using the up and down arrows
Ctrl-R is one of the most useful commands on the terminal and it allows to browse through command history and re-use it again.
On bash shell there is a much simpler way to search through your command history on terminal. Basically you can start typing the initial letter and then use up and down arrow keys to search the history and re-use the command.
histrory-search-* commands enable this fast search of command history. Two of the commands that lets you search command history are
history-search-forward ()
Search forward through the history for the string of characters between the start of the current line and the point. The search string must match at the beginning of a history line. This is a non-incremental search. By default, this command is unbound.
history-search-backward ()
Search backward through the history for the string of characters between the start of the current line and the point. The search string must match at the beginning of a history line. This is a non-incremental search. By default, this command is unbound.
Add the following two statements to .inputrc file in your home directory
“\e[A”: history-search-backward # arrow up
“\e[B”: history-search-forward # arrow down
Then you can simply start typing the first few characters of command and then use the up and down arrow keys to go through your previous commands stored in
in your .bash_history that begin with that characters you typed.
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http://mathematica.stackexchange.com/questions/71416/parametric-function/71419
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# Parametric Function
i'm struggling to implement the following parametric function:
I need to create a g function with two arguments (w and v). If w and v are not empty lists, then it will return a list containing two other lists: - one containing the elements of w that do not occur in v, - and the other containing the elements of v that do not occur in w, If one of w or v are empty lists, it should return a message "One of the lists is empty".
Hope anyone can help me out here, thanks in advance.
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Seems quite straightforward. Check the docs for If[] and Complement[] – belisarius Jan 9 at 17:37
Welcome to Mathematica.SE! I suggest the following: 1) As you receive help, try to give it too, by answering questions in your area of expertise. 2) Read the faq! 3) When you see good questions and answers, vote them up by clicking the gray triangles, because the credibility of the system is based on the reputation gained by users sharing their knowledge. Also, please remember to accept the answer, if any, that solves your problem, by clicking the checkmark sign! – belisarius Jan 9 at 17:40
Try g[w_, v_] := If[w == {} || v == {}, "D'oh!", {Complement[w, v], Complement[v, w]}]. – DumpsterDoofus Jan 9 at 17:43
I added my comment as an answer. If people think this question is trivial enough to be closed, I'll delete my answer and vote to close for "easily found in the documentation" and leave my answer as the comment above. – DumpsterDoofus Jan 9 at 18:00
Regardless, the title is unrelated to the question (which has nothing to do with parametric functions). If this question is to remain, the title should be changed to reflect the actual question. – David G. Stork Jan 9 at 20:16
Try the following:
g[w_, v_] := If[w == {} || v == {}, "D'oh!", {Complement[w, v], Complement[v, w]}]
Some tests:
g[{2, 3, 4}, {2, 5}]
g[{2}, {}]
producing
{{3, 4}, {5}}
"D'oh!"
-
Here is an alternative, using dispatch between multiple definitions:
g[{},_] = g[_,{}] = "One of the lists is empty";
g[a_,b_] := { a~Complement~b, b~Complement~a };
If you like syntactic sugar, you could also write the second line as
g[a_,b_] := Complement @@@ { {a,b}, {b,a} };
-
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http://noobstarter.com/buy-nootropics-ireland-brain-bounce-orange-pill.html
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But Baldino may have been overly modest. In 2002, researchers at Cambridge University gave 60 healthy young male volunteers a battery of standard cognitive tests. One group received modafinil, the other a placebo. The modafinil group performed better on several tasks, such as the "digit span" test, in which subjects are asked to repeat increasingly longer strings of numbers forwards, then backwards. They also did better in recognising repeated visual patterns and at a spatial-planning challenge known as the Tower of London task. (It's not nearly as fun as it sounds.) Writing in the journal Psychopharmacology, the study's authors said the results suggested that "modafinil offers significant potential as a cognitive enhancer".
As a student Seltzer used both Adderall and piracetam. Now, after a hiatus of several years, he has recently resumed taking neuroenhancers. In addition to piracetam, he took a stack of supplements that he thought helped his brain to function: fish oils, five antioxidants, a product called ChocoMind and a number of others, all available at the health-food store. He was thinking about adding modafinil, but hadn't yet. For breakfast every morning he concocted a slurry of oatmeal, berries, soy milk, pomegranate juice, flaxseed, almond meal, raw eggs and protein powder. The goal behind the recipe was efficiency: to rely on "one goop you could eat or drink that would have everything you need nutritionally for your brain and body. I wanted to be able to keep it down - that was it." (He told me this in the kitchen of his apartment; he lives with a roommate, who walked in while we were talking, listened perplexedly for a moment, then put a frozen pizza in the oven.)
She provides many examples of observational studies where lower intakes of a certain nutrient were correlated with cognitive impairment. Obviously, if someone is deficient in a vitamin or other nutrient, the deficiency should be corrected. But she doesn’t have any evidence from prospective interventional studies showing that, in practice, altering diet significantly improves cognition for people who are deficient, much less in people who are not deficient.
Modafinil, also known as Provigil, Modalert, and Alertec, was originally made and marketed for sleep disorders, and has been prescribed in the US for this reason since 1998. It was found only by chance to help with focus and concentration, and it is only approved for the treatment of narcolepsy, shift work sleep disorder, and obstructive sleep apnea.
The amphetamine mix branded Adderall is terribly expensive to obtain even compared to modafinil, due to its tight regulation (a lower schedule than modafinil), popularity in college as a study drug, and reportedly moves by its manufacture to exploit its privileged position as a licensed amphetamine maker to extract more consumer surplus. I paid roughly $4 a pill but could have paid up to$10. Good stimulant hygiene involves recovery periods to avoid one’s body adapting to eliminate the stimulating effects, so even if Adderall was the answer to all my woes, I would not be using it more than 2 or 3 times a week. Assuming 50 uses a year (for specific projects, let’s say, and not ordinary aimless usage), that’s a cool $200 a year. My general belief was that Adderall would be too much of a stimulant for me, as I am amphetamine-naive and Adderall has a bad reputation for letting one waste time on unimportant things. We could say my prediction was 50% that Adderall would be useful and worth investigating further. The experiment was pretty simple: blind randomized pills, 10 placebo & 10 active. I took notes on how productive I was and the next day guessed whether it was placebo or Adderall before breaking the seal and finding out. I didn’t do any formal statistics for it, much less a power calculation, so let’s try to be conservative by penalizing the information quality heavily and assume it had 25%. So \frac{200 - 0}{\ln 1.05} \times 0.50 \times 0.25 = 512! The experiment probably used up no more than an hour or two total. This product is a miracle! I have purchased it TWICE because it is so helpful with my memory and cognition. I bought this product because I needed to strengthen my memory and focus, and I wanted to be awake when I did it! I had just switched to a job that is second shift (2PM-11PM) and it was very difficult to adjust to those hours AND learn all of the new technical systems required for my new job. But after taking this supplement, I noticed a HUGE difference in a few days! I was awake and alert like it was 11AM everyday. But it wasn’t like the jolt you sometimes get from caffeine, more like an alertness after a good night’s sleep. No jitters, no headaches, no stomach upset. Just energy and the feeling of being AWAKE. I am now telling all of my co-workers about it! She speaks from professional and personal experience. When she first moved to the United States from Italy at age 24 she was struck by how shifting from the Mediterranean-style diet she grew up on to a standard American diet negatively impacted her physical health and work performance. The experience led her to more closely study nutrition and the link between diet and brain health. In this excerpt from a longer interview, she discusses the brain foods you should be eating. These are the most highly studied ingredients and must be combined together to achieve effective results. If any one ingredient is missing in the formula, you may not get the full cognitive benefits of the pill. It is important to go with a company that has these critical ingredients as well as a complete array of supporting ingredients to improve their absorption and effectiveness. Anything less than the correct mix will not work effectively. Directions — as a dietary supplement take 2 veggie capsules once a day . For best results take 20-30 min before a meal with an 8oz. Glass of water or as directed by your healthcare professional. As a dietary supplement take two (2) veggie capsules once a day. For best results take 20-30 minutes before a meal with an 8oz. glass of water or as directed by your healthcare professional. — Suggested Use: As a dietary supplement, adults take one (1) capsule per day. Do not exceed 2 capsules per day. — The U. S. nootropics industry was valued at more than$1.3 billion in 2015 and is projected to reach $6 billion by 2024. This growth is due in part to slick marketing from biohacking “experts” such as Dave Asprey (founder of Bulletproof) and Josiah Zayner, Ph.D. (CEO of the Odin), who’ve built big social-media and podcast followings as well as customer bases. At the grassroots level, there are meetups across the country like the one at Idea Coffee, plus a vibrant online community. …It is without activity in man! Certainly not for the lack of trying, as some of the dosage trials that are tucked away in the literature (as abstracted in the Qualitative Comments given above) are pretty heavy duty. Actually, I truly doubt that all of the experimenters used exactly that phrase, No effects, but it is patently obvious that no effects were found. It happened to be the phrase I had used in my own notes. A recent study at the University of Innsbruck in Austria found that participants that drank two cups of coffee per day improved memory, reaction time, and neuron signaling, more than the control. More notably, the 676 daily coffee drinker participants experienced less mental decline than nondrinkers over a ten-year period. In other words, bottoms up on your cup of Joe! Whether you want to optimise your nutrition during exam season or simply want to stay sharp in your next work meeting, paying attention to your diet can really pay off. Although there is no single 'brain food' that can protect against age-related disorders such as Alzheimers' or dementia, and there are many other medical conditions that can affect the brain, paying attention to what you eat gives you the best chance of getting all the nutrients you need for cognitive health. But Baldino may have been overly modest. In 2002, researchers at Cambridge University gave 60 healthy young male volunteers a battery of standard cognitive tests. One group received modafinil, the other a placebo. The modafinil group performed better on several tasks, such as the "digit span" test, in which subjects are asked to repeat increasingly longer strings of numbers forwards, then backwards. They also did better in recognising repeated visual patterns and at a spatial-planning challenge known as the Tower of London task. (It's not nearly as fun as it sounds.) Writing in the journal Psychopharmacology, the study's authors said the results suggested that "modafinil offers significant potential as a cognitive enhancer". This calculation - reaping only \frac{7}{9} of the naive expectation - gives one pause. How serious is the sleep rebound? In another article, I point to a mice study that sleep deficits can take 28 days to repay. What if the gain from modafinil is entirely wiped out by repayment and all it did was defer sleep? Would that render modafinil a waste of money? Perhaps. Thinking on it, I believe deferring sleep is of some value, but I cannot decide whether it is a net profit. If you're still unsure about whether you should take GodMode gamer pills, definitely talk to your doctor. If that conversation goes well and you still aren't sold, Boss Level Labs provides a list of "pro users" of its product, which includes a handful of game developers, people who lift weights, someone who is a "celebrity financial advisor and motivational speaker," and a retired Hungarian chess grandmaster named Judit Polgár. The most common front-line of treatment for ADHD is medication and cognitive behavioural therapy (CBT). Prescriptions for ADHD drugs such as Ritalin, have doubled to 922,000 a year in the last decade, and whilst it offers symptom management for many, it has also been found to have significant negative side effects such as weight loss, liver toxicity, and suicidal thoughts, and in the short term may suppress pubertal growth. The aetiology of ADHD is multifactorial, meaning that there are varying influencing factors that drive the symptoms. This is perhaps why this condition has been hard to study and find effective treatment for. Perhaps the most well-known natural nootropic stimulant and neuroenhancer is caffeine. Caffeine has been shown to prevent memory deficits in experimental models of Alzheimer’s disease and may even restore memory following impairment. In studies performed with college students, caffeine was shown to have particularly potent effects on memory improvement during students’ non-optimal time of day, in this case, early in the morning. Caffeine’s benefits go even further because it’s never found in an isolated vacuum in nature, meaning that it’s always located in some kind of plant such as green tea or bean such as coffee that carry additional beneficial compounds which often enhance the effects of caffeine, including, most notably, certain cholesterols, polyphenols and antioxidants. In fact, one study determined that caffeine alone does not account for the benefits caused by coffee consumption. Rather, the phytochemical content of coffee (coffee contains over 1,000 different natural chemicals!) gives it potent antioxidant and anti-inflammatory properties that complement the neuroprotective effects of caffeine on the central nervous system. My impression after the first two days (2 doses of 400mg each, one with breakfast & then lunch) was positive. I did not have the rumored digestion problems, and the first day went excellently: I was up until 1:30AM working and even then didn’t feel like going to bed - and I probably should have since I then slept abominably, which made the second day merely a good day. The third day I took none and it was an ordinary day. This is consistent with what I expected from the LEF l-threonate & TruBrain glycinate/lycinate, and so it is worth investigating with a self-experiment. Please take care when you’re out there on the web or in the world shopping for something to help that in progress novel or craft project of yours along. Take all care when planning on taking anything, be it a nootropic, smart drug, or brain enhancer, and do your research before buying. Make sure your so-called ‘best brain pill’ really is the best brain pill for you. 70 pairs is 140 blocks; we can drop to 36 pairs or 72 blocks if we accept a power of 0.5/50% chance of reaching significance. (Or we could economize by hoping that the effect size is not 3.5 but maybe twice the pessimistic guess; a d=0.5 at 50% power requires only 12 pairs of 24 blocks.) 70 pairs of blocks of 2 weeks, with 2 pills a day requires (70 \times 2) \times (2 \times 7) \times 2 = 3920 pills. I don’t even have that many empty pills! I have <500; 500 would supply 250 days, which would yield 18 2-week blocks which could give 9 pairs. 9 pairs would give me a power of: Effect of Brain Pill on working memory capacity will be accessed by improvement in mean response time and accuracy measured by working memory battery from baseline to end of the study. Effect of Brain Pill is also accessed on Neurophysiological improvement in working memory as measured by electroencephelogram (EEG) from baseline to end of the study. Also improvement in attention and concentration will be accessed from baseline to end of the study by Picture recognition test. It can easily pass through the blood-brain barrier, and is known to protect the nerve tissues present in the brain. There is evidence that the acid plays an instrumental role in preventing strokes in adults by decreasing the number of free radicals in the body. It increases the production of acetylcholine , a neurotransmitter that most Alzheimer’s patients are deficit in. Amongst the brain focus supplements that are currently available in the nootropic drug market, Modafinil is probably the most common focus drug used by people, and it’s actually touted to be the best nootropic available today. It is a powerful cognitive enhancer that is great for boosting your overall alertness with least side effects. However, to get your hands on this drug, you require a prescription. So I eventually got around to ordering another thing of nicotine gum, Habitrol Nicotine Gum, 4mg MINT flavor COATED gum. 96 pieces per box. Gum should be easier to double-blind myself with than nicotine patches - just buy some mint gum. If 4mg is too much, cut the gum in half or whatever. When it arrived, my hopes were borne out: the gum was rectangular and soft, which made it easy to cut into fourths. (I was more than a little nonplussed when the mushroom seller included a little pamphlet educating one about how papaya leaves can cure cancer, and how I’m shortening my life by decades by not eating many raw fruits & vegetables. There were some studies cited, but usually for points disconnected from any actual curing or longevity-inducing results.) Modafinil, also known as Provigil, Modalert, and Alertec, was originally made and marketed for sleep disorders, and has been prescribed in the US for this reason since 1998. It was found only by chance to help with focus and concentration, and it is only approved for the treatment of narcolepsy, shift work sleep disorder, and obstructive sleep apnea. Cephalon executives have repeatedly said that they do not condone off-label use of Provigil, but in 2002 the company was reprimanded by the FDA for distributing marketing materials that presented the drug as a remedy for tiredness, "decreased activity" and other supposed ailments. And in 2008 Cephalon paid$425m and pleaded guilty to a federal criminal charge relating to its promotion of off-label uses for Provigil and two other drugs. Later this year, Cephalon plans to introduce Nuvigil, a longer-lasting variant of Provigil. Candace Steele, a spokesperson, said: "We're exploring its possibilities to treat excessive sleepiness associated with schizophrenia, bipolar depression, traumatic injury and jet lag." Though she emphasised that Cephalon was not developing Nuvigil as a neuroenhancer, she noted: "As part of the preparation for some of these diseases, we're looking to see if there's improvement in cognition."
For starters, it’s one of the highest antioxidant-rich foods known to man, including vitamin C and vitamin K and fiber. Because of their high levels of gallic acid, blueberries are especially good at protecting our brains from degeneration and stress. Get your daily dose of brain berries in an Omega Blueberry Smoothie, Pumpkin Blueberry Pancakes or in a Healthy Blueberry Cobbler.
The ‘Brain-Gut Axis’ is a term used to describe the two-way communication system between our digestive tract and the brain. A growing body of research into this axis demonstrates how much influence the gut can have over the brain and vice versa (1). When we speak about reactions to foods, we most commonly understand them as immediate and often dangerous allergic responses, such as the constriction of the throat and trouble breathing, or dizziness and fainting. It is usually easy to pinpoint the food that causes these reactions because of the immediate immune system response, caused by a type of immune cell known as IgE antibodies. In contrast to this, food intolerances are mediated by IgG antibodies and these reactions can take up to 48 hours to have an effect. Symptoms related to IgG reactions can often be manifested as chronic issues like joint ache, IBS and depression or anxiety, which are often overlooked and not associated with what we eat.
Fitzgerald 2012 and the general absence of successful experiments suggests not, as does the general historic failure of scores of IQ-related interventions in healthy young adults. Of the 10 studies listed in the original section dealing with iodine in children or adults, only 2 show any benefit; in lieu of a meta-analysis, a rule of thumb would be 20%, but both those studies used a package of dozens of nutrients - and not just iodine - so if the responsible substance were randomly picked, that suggests we ought to give it a chance of 20% \times \frac{1}{\text{dozens}} of being iodine! I may be unduly optimistic if I give this as much as 10%.
As professionals and aging baby boomers alike become more interested in enhancing their own brain power (either to achieve more in a workday or to stave off cognitive decline), a huge market has sprung up for nonprescription nootropic supplements. These products don’t convince Sahakian: “As a clinician scientist, I am interested in evidence-based cognitive enhancement,” she says. “Many companies produce supplements, but few, if any, have double-blind, placebo-controlled studies to show that these supplements are cognitive enhancers.” Plus, supplements aren’t regulated by the U.S. Food and Drug Administration (FDA), so consumers don’t have that assurance as to exactly what they are getting. Check out these 15 memory exercises proven to keep your brain sharp.
At this point I began to get bored with it and the lack of apparent effects, so I began a pilot trial: I’d use the LED set for 10 minutes every few days before 2PM, record, and in a few months look for a correlation with my daily self-ratings of mood/productivity (for 2.5 years I’ve asked myself at the end of each day whether I did more, the usual, or less work done that day than average, so 2=below-average, 3=average, 4=above-average; it’s ad hoc, but in some factor analyses I’ve been playing with, it seems to load on a lot of other variables I’ve measured, so I think it’s meaningful).
The effect? 3 or 4 weeks later, I’m not sure. When I began putting all of my nootropic powders into pill-form, I put half a lithium pill in each, and nevertheless ran out of lithium fairly quickly (3kg of piracetam makes for >4000 OO-size pills); those capsules were buried at the bottom of the bucket under lithium-less pills. So I suddenly went cold-turkey on lithium. Reflecting on the past 2 weeks, I seem to have been less optimistic and productive, with items now lingering on my To-Do list which I didn’t expect to. An effect? Possibly.
In addition to diet, there are many other things you can also do related to lifestyle, such as stress management through mindfulness (8) or gentle movement such as pre or post natal yoga (9), which have both shown to be incredibly helpful in encouraging mental wellbeing. If you feel you need extra support, personalised nutritional therapy can be very helpful as there can often be other drivers such as nutrient deficiencies and digestive complaints that can play a significant role in mental health and will need to be addressed in a way that is tailored to the individual.
Jesper Noehr, 30, reels off the ingredients in the chemical cocktail he’s been taking every day before work for the past six months. It’s a mixture of exotic dietary supplements and research chemicals that he says gives him an edge in his job without ill effects: better memory, more clarity and focus and enhanced problem-solving abilities. “I can keep a lot of things on my mind at once,” says Noehr, who is chief technology officer for a San Francisco startup.
The problems with our mental functions begin if the blood flow to the brain cells is disrupted regardless of the reasons. There are countless capillaries in the head, which supply the brain with essential nutrients and oxygen. If the blood doesn’t get to these capillaries, your optimal mental performance is compromised. Here’s a term worth remembering – hypoperfusion. If you’re suffering from hypoperfusion, then this means you are having problems with the blood flow to your brain. Here’s a quick overview of the factors that most commonly cause hypoperfusion:
But before you dismiss the diet-brain connection as mere conjecture, keep in mind that study after study has found a relationship between what we put in our mouths and how well we can perform important thinking and memory tasks. While certain nutrients may specifically assist brain function, there is also the totality of our diets to consider. One recent U.K. study found that a diet high in saturated fat actually caused damage to neurons that control energy and appetite in mice. And several well-regarded studies have shown that meal timing is an important predictor of performance. For example, research shows that eating breakfast can improve the memory and acquisition skills of schoolchildren.
If all of this sounds great to you, get ready to level up your brain to game like a god with GodMode. Unless, you know, you're under 18, pregnant, potentially have any pre-existing medical conditions, are taking any prescription medications, are otherwise ingesting caffeine or taking other stimulants, or you don't want to drop \$60 on gamer pills. Then, you know, don't.
To our volunteers: We could not have asked for a more committed, creative, tireless group of voluneers. We hope you count yourself as fierce advocates who helped build a youth-positive city, because we always have. Thank you for giving Brainfood programs a place in your life and for bringing your energy and skills to our community. You took our spark and turned it into a fire, and we’re so grateful.
I’ve tried a few different ways of taking my nootropics—in the morning, in the afternoon, in addition to coffee, as a replacement for coffee—and so far, the effects I'm feeling are much more subtle than I expected. There’s no sweaty-palmed intensity, no eight-hour uninterruptible work sprints, and none of the hyperactivity you’d associate with a caffeine high. It’s just a sensation of being a little amped up, and of being slightly less distracted than normal.
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Is lifestyle truly important, though? According to Dr. Lisa, "genes load the gun, but lifestyle pulls the trigger." As someone who grew up very aware of my genetic predisposition (diabetes, cardiovascular diseases, breast cancer — you name it and someone in my family has it), I always thought that this weighed heavily on whether or not someone manifests an illness. But, groundbreaking research on epigenetics actually states the contrary.
One thing to notice is that the default case matters a lot. This asymmetry is because you switch decisions in different possible worlds - when you would take Adderall but stop you’re in the world where Adderall doesn’t work, and when you wouldn’t take Adderall but do you’re in the world where Adderall does work (in the perfect information case, at least). One of the ways you can visualize this is that you don’t penalize tests for giving you true negative information, and you reward them for giving you true positive information. (This might be worth a post by itself, and is very Litany of Gendlin.)
You have the highest density of mitochondria in your brain’s prefrontal cortex, which helps to explain why I feel Unfair Advantage in my head first. You have the second highest density in your heart, which is probably why I feel it in the center of my chest next. Mitochondrial energizers can have profound nootropic effects! At higher doses mitochondrial energizers also make for an excellent pre-workout supplements.
Caffeine dose dependently decreased the 1,25(OH)(2)D(3) induced VDR expression and at concentrations of 1 and 10mM, VDR expression was decreased by about 50-70%, respectively. In addition, the 1,25(OH)(2)D(3) induced alkaline phosphatase activity was also reduced at similar doses thus affecting the osteoblastic function. The basal ALP activity was not affected with increasing doses of caffeine. Overall, our results suggest that caffeine affects 1,25(OH)(2)D(3) stimulated VDR protein expression and 1,25(OH)(2)D(3) mediated actions in human osteoblast cells.
Power-wise, the effects of testosterone are generally reported to be strong and unmistakable. Even a short experiment should work. I would want to measure DNB scores & Mnemosyne review averages as usual, to verify no gross mental deficits; the important measures would be physical activity, so either pedometer or miles on treadmill, and general productivity/mood. The former 2 variables should remain the same or increase, and the latter 2 should increase.
“In this fascinating investigation, Lisa Mosconi presents research that crosses disciplines to argue that what goes on in your brain—from your mood to your cognitive abilities—is very closely tied to what you put on your plate. In addition to being a compelling read, readers will find tips and outlines on ways they can change their diets for optimal brain health.”
Seriously. Every single thing you experience comes through your brain. It create the fabric of your reality, and by the same token, the energy your brain makes is what allows you to shape that reality. Work, relationships, success, happiness — everything depends on your brain, and building a stronger one will trigger upgrades that extend across every aspect of your life.
The principal metric would be mood, however defined. Zeo’s web interface & data export includes a field for Day Feel, which is a rating 1-5 of general mood & quality of day. I can record a similar metric at the end of each day. 1-5 might be a little crude even with a year of data, so a more sophisticated measure might be in order. The first mood study is paywalled so I’m not sure what they used, but Shiotsuki 2008 used State-Trait of Anxiety Inventory (STAI) and Profiles of Mood States Test (POMS). The full POMS sounds too long to use daily, but the Brief POMS might work. In the original 1987 paper A brief POMS measure of distress for cancer patients, patients answering this questionnaire had a mean total mean of 10.43 (standard deviation 8.87). Is this the best way to measure mood? I’ve asked Seth Roberts; he suggested using a 0-100 scale, but personally, there’s no way I can assess my mood on 0-100. My mood is sufficiently stable (to me) that 0-5 is asking a bit much, even.
With so many different ones to choose from, choosing the best nootropics for you can be overwhelming at times. As usual, a decision this important will require research. Study up on the top nootropics which catch your eye the most. The nootropics you take will depend on what you want the enhancement for. The ingredients within each nootropic determine its specific function. For example, some nootropics contain ginkgo biloba, which can help memory, thinking speed, and increase attention span. Check the nootropic ingredients as you determine what end results you want to see.
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http://mathhelpforum.com/calculus/176245-how-show-sum_-n-0-n-1-exp-ix-n-frac-1-exp-inx-1-exp-ix.html
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# Thread: how to show that \sum_{n=0}^{N-1} (exp(ix))^n = \frac {1 - exp(iNx)} {1 - exp(ix)}
1. ## how to show that \sum_{n=0}^{N-1} (exp(ix))^n = \frac {1 - exp(iNx)} {1 - exp(ix)}
Hello guys.
I started to study complex numbers on this semester. I'm stuck on a problem. I have the solution of this problem, but i cannot understand one of the equalities. My dificulty is how to show that
$\sum_{n=0}^{N-1} (exp(ix))^n = \frac {1 - exp(iNx)} {1 - exp(ix)}
$
I confess that i don't understand this equality. Any explanation would be great for me. Thanks!
2. It's a finite geometric series of $\displaystyle N$ terms, with $\displaystyle a = 1, r = e^{ix}$.
3. Originally Posted by Prove It
It's a finite geometric series of $\displaystyle N$ terms, with $\displaystyle a = 1, r = e^{ix}$.
Thank's!
4. Originally Posted by Prove It
It's a finite geometric series of $\displaystyle N$ terms, with $\displaystyle a = 1, r = e^{ix}$.
Indeed! Thank's
5. Originally Posted by hurz
$\sum_{n=0}^{N-1} (exp(ix))^n = \frac {1 - exp(iNx)} {1 - exp(ix)}
$
By the way, you can use a backslash (\) before $exp$ to get the following operator view $\exp$.
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https://cerncourier.com/a/anais-challenges-dama-dark-matter-claim/
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# ANAIS challenges DAMA dark-matter claim
24 March 2021
Despite the strong indirect evidence for the existence of dark matter, a plethora of direct searches have not resulted in a positive detection. The exception to this are the famous results from the DAMA/NaI experiment at Gran Sasso underground laboratory in Italy, first reported in the late 1990s, which show a modulating signal compatible with Earth moving through a region containing Weakly Interacting Massive Particles (WIMPs). These results were backed-up more recently with measurements from the follow-up DAMA/LIBRA detector. Combining the data in 2018, the evidence reported for a dark-matter signal is as high as 13 sigma.Now, the Annual modulation with NaI Scintillators (ANAIS) collaboration, which aims to directly reproduce the DAMA results using the same detector concept, has published the results from their first three years of operations. The results, which were presented today at Rencontres de Moriond, show a clear contradiction with DAMA, indicating that we are still no closer to finding dark matter.
The DAMA results are based on searches for an annual modulation in the interaction rate of WIMPs in a detector comprising NaI crystals. First theoretically proposed in 1986 by Andrzej Drukier, Katherine Freese and David Spergel, this modulation is a result of the difference in velocity of Earth with respect to the dark-matter halo of the galaxy. On 2 June, the velocities of Earth and the Sun are aligned with respect to the galaxy, whereas half a year later they are oppositely aligned, resulting in a lower cross section for WIMPs with a detector placed on Earth. Although this method has advantages compared to more direct detection methods, it requires that other potential sources of such a seasonal modulation be ruled out. Despite the significant modulation with the correct phase observed by DAMA, its results were not immediately accepted as a clear signal of dark matter due to the remaining possibility of instrumental effects, seasonal background modulation or artifacts from the analysis.
Over the years the significance of the DAMA results has continued to increase while other dark-matter searches, in particular with the XENON1T and LUX experiments, found no evidence of WIMPs capable of explaining the DAMA results. The fact that only the final analysis products from DAMA have been made public has also hampered attempts to prove or disprove alternative origins of the modulation. To overcome this, the ANAIS collaboration set out to reproduce the data with an independent detector intentionally similar to DAMA, consisting of NaI(Tl) scintillators readout by photomultipliers placed in the Canfranc Underground Laboratory deep beneath the Pyrenees in northern Spain. Using this method ANAIS can rule out any instrument-induced effects while producing data in a controlled way and studying it in detail with different analysis procedures.
The ANAIS results agree with the first results published by the COSINE-100 collaboration
The first three years of ANAIS data have now been unblinded, and the results were posted on arXiv on 1 March. None of the analysis methods used show any signs of a modulation, with a statistical analysis ruling out the DAMA results at 99% confidence. The results therefore narrow down the possible causes of the modulation observed by DAMA to either differences in the detector compared to ANAIS, or in the analysis method. One specific issue raised by the ANAIS collaboration regards the background-subtraction method. In the DAMA results the mean background rate for each year is subtracted from the raw data for that full year. In case the background during that year is not constant, however, this will produce an artificial saw-tooth shape which, with the limited statistics, can be fitted with a sinusoidal. This effect was already pointed out in a publication by a group from INFN in 2020, which showed how a slowly increasing background is capable of producing the exact modulation observed by DAMA. The ANAIS collaboration describes their background in detail, shows that it is indeed not constant, and provides suggestions for a more robust handling of the background.
The ANAIS results also agree with the first results published by the COSINE-100 collaboration in 2019 which, again using a NaI-based detector, found no evidence of a yearly modulation. Thanks to the continued experimental efforts of these two groups, and with the ANAIS collaboration planning to make their data public to allow independent analyses, the more than 20 year-old DAMA anomaly looks likely to be settled in the next few years.
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http://docs.thevirtualbrain.com/manuals/DeveloperReference/DeveloperReferenceManual.html
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class legendtext
Legend
Term Description
TVB The Virtual Brain Project, including hardware and software components, an open-source tool for the neuroscience community.
TVB Framework TVB Software skeleton (architecture and concrete artifacts), where different independent libraries can be plugged-in.
TVB Full Version TVB software distribution package, with all the components included, intended to be deployed on a cluster hardware. It will have a web interface.
TVB Light Version TVB software distribution package, stripped of several “heavy” components, for the purpose of being distributed on a researcher’s laptop/PC/node. This version is to be decided if it will have the same web interface, or will have a stand-alone graphical or console interface.
TVB Team Randy McIntosh, Viktor Jirsa, Laurent Pezard, Yann Manhoun, Jean-Luc Blanc, Stuart Knock, Noelia Montejo, Marmaduke Woodman, Paula Sanz Leon Jochen Mersmann, Calin Pavel, Bogdan Neacsa, Ionel Ortelecan, Lia Domide
# Introduction¶
The Virtual Brain project (TVB project) has the purpose of offering some modern tools to the Neurosciences community, for computing, simulating and analyzing functional and structural data of human brains. It will try to bring customized engineering tools into the hands of basic and clinical Neuroscience researchers. TVB will be a modeling and analysis platform, which will allow the simulation of functional brain data specific to individual brain structures and connectivity. Experimental functional and structural data will be read into TVB and the same degree of analyses will be applicable to both simulated and experimental data.
The final goal of TVB is to create a new revolutionary tool for clinical interventions. As an example case, a clinical researcher will be able to upload brain imaging data from their patients unique neural architecture after a stroke, for example, into the synthetic healthy brain model to see how it responds to the disruption of normal network patterns and attempts to re-stabilize. This will assist the clinician in determining the treatment interventions that will likely have the best outcomes for their patient.
The project is not the first simulation tool in the computational neuroscience community, though it is the first for large-scale brain modeling, and arguably the most ambitious one. TVB will be open to learn from and to take advantage of new existing tools. TVB is intended to be an open-source software-product, available for usage in an on-line installation, but also available for download and install by any interested person or institution.
TVB project has the goal to manipulate multiple brain models, at a middle-grain to large-scale level. It doesn’t intend to build brain models at the grain of neurons, but will use information from microscopic models to improve the performance of the neural population models acting as the building blocks of the Virtual Brain network.
TVB is not a project of artificial intelligence, but it rather simulates the physical characteristics of the human brain. TVB has also the purpose of building a high-performance cluster, accessible over web from anywhere. It will avoid the necessity of multiplying big and powerful computers in several laboratories.
Input data for TVB can be retrieved from multiple sources: functional neuroimaging like EEG, MEG, sEEG, fMRI and structural imaging such as MRI, DTI, DSI, but also data from the literature etc.
This paper is intended to give a brief starting point on the Virtual Brain project, from the technical point of view. It will refer to architectural and few implementation details. It is meant to bring together important architectural decisions, some already made and others in course of being accepted.
This white-paper should provide the technical fundaments for future implementations of components and changes required for the pieces of software already existent. Several partners will work in parallel on multiple project parts, so this document will serve as a guiding line in offering an overall image of the entire Virtual Brain project to the involved programming teams.
The Virtual Brain project cannot exist without other previous open-source projects in the area of Neuroscience, some of which are listed in the references part of the document. Nevertheless, from the technical point of view, the Virtual Brain is unique in its modern and new access to the domain.
# Requirements¶
## Functional Requirements¶
• Scientific Usage
These three are the main functional requirements for TVB, from the science point of view:
• possibility to configure, execute and monitor large scale brain simulations;
• configure and execute data analysis algorithms and methods;
• visualize brain input data and analysis results.
When using TVB, a researcher needs to have the freedom to configure simulations and data analysis. A researcher needs to both interfere with existing simulation or libraries for analysis, by configuring the equations of the brain network used by the tools, and also to be able to build his/her own libraries and to plug them into the TVB Framework. The extensions of functionality of TVB should be as easy as possible, which means as little coding as possible.
A common use of TVB will be the scanning of parameter spaces of the brain network. Hence TVB will offer the functionality of operating in batch mode, in which a given simulation can be performed multiple times as a parameter is changed. The results will be captured in parametric maps of convenient measures and appropriately visualized.
Each user can firstly view, but also download or export his/her own results obtained with TVB, in multiple formats. The final results will be captured in a set of images of high quality, sufficient to be used fort publications in scientific articles.
Several brain models will be used that are composed of the connectivity matrix and a network node model. Generic default brain models will exist in the system, but also each user will be able to upload individualized models (for instance of a patient), in a predefined format. Brain models are based on previous brain-measurements. Users can choose what brain model they want to use for each particular simulation or data analysis they initiate.
• Connect to External Storages
In the neuroscience community, several open data storages already exist, containing useful input data for brain modeling and patient analyses. It is one of the important requirements for TVB to connect to such storages to import and export data from/to them. Different protocols will be used when communicating with such External Storages.
• Use in clinics
TVB is not intended in the first place to become a diagnostic tool of the clinician. However, the clinical researcher will benefit from the use of TVB to design new treatment strategies, test out hypotheses and explore alternative avenues of brain repair. In the long run, TVB may become a precursor of a future diagnostic tool.
• Application Interface
The entire system should be accessible through a Web-Interface. The web-interface should be built on W3C-Standards; HTML-5 will provide the basic support for visualization. A 3D representation is expected for the brain models, in a browser environment, along with graphs and charts for several 2D results.
Virtual Reality has grown a lot in the last few years, and fast, light, browser-based applications had appeared, impressing the world of computer science. We should learn from projects like: OnLive and Otoy to bring the power of graphics to the clients through a light web interface. However it might be necessary to allow for the usage of additional, browserenabled software (like Java-Applets or Flash), dependent of other open-source Projects from the domain we want to embrace.
Another level of usability to be achieved is a script interface for advanced users. The script interface will provide rapidity and straight access to the system.
The third level of usability is through a desktop, Stand-Alone Interface. This interface is not yet fully acknowledged as a requirement, but it an option nice to have. This interface could be the client-end for both TVB-Full version and Light version. This type of interface could give the user the feeling of a “really installed” application, especially for the Light Version of TVB, and would nicely mimic behavior of other existing tools in this field.
• Multi-user application
You need to have an account to access the VB system, at least for TVB Full Version distribution. A log-in page will appear, and each user will have its own data to manipulate and view, separated from the other users. Some information might be public, for all users to share (like brain structural data). For TVB Light Version, multi-user environment will not be included.
Single users will be able to make their projects or parts of their results available either to all users (public) or designated other single users. In the latter case, the ensemble of single users with shared access rights to a common project forms a user group.
Multi-tenancy will be a good add-on here, too, as we work here with clinical data, which should live under the highest data-privacy standards. So if a patient gave consent, that a group of Doctors may look at his data, that should not apply to all Users of the System!
• Customizable dashboard
A VB user will have its own personal page, something like a dashboard, where he/she can compose his/her own view over Virtual Brain. This page needs to be easily configurable, and already predefined for a new user with basic functionality (maybe dependent on the user’s role, type or group).
Different VB elements like: simulation-status, 3D-models, Graph-models, Data-sets, working-queues, transformation-steps etc. shall all have different interfaces, dependent on the current user’s role. Thus, a researcher will see more details than a clinician, and a developer will have a more technical view of all this elements.
The roles that are currently known for the VB view are: researcher, clinician and maybe developer, but others might be mentioned as the discussions evolve.
## Nonfunctional Requirements¶
• Cluster infrastructure
Performance is a common requirement in any decent application, especially when user interaction exists. Regardless that, in the Virtual Brain project, some simulations might take days or weeks to be executed on regular stations, and multiple users are expected to want their data processed in the same time.
Besides the obvious performance requirement, a cluster or a grid can offer a clear separation in executing tasks. In a multi-node environment different nodes could execute different types of tasks. For example we could have nodes for different users, or nodes for brain-simulations and nodes for graphical operations. TVB is so far not intended to make use of parallel programming across nodes for the brain network model. The here mentioned task distribution across nodes is intended for tasks within TVB, but not the numerical simulation of the brain network equations. Having tasks executed over a cluster or a grid is a requirement for the Virtual Brain’s Full Version deployment.
• Open software
TVB is to be distributed as an open-source software, thus only Open Source tools and standards are to be used when developing it.
However that still means, that we have to take a decision on the license, which we want to use for The Virtual Brain system and we need to pay attention, to only use Software, which has a compatible license.
• Shrink-Wrap the software
Some users, researchers or developers in the project, might want to use the product on their local machines. Virtual Brain will offer the possibility to download and locally install, with a customizable set of parameters, the product. The software shall shrink to the needs of each person that downloads it. This TVB Light version, might come with a different Graphical User Interface, than the web interface for TVB Full.
An installer shall be made available for the operating systems of Windows, Macintosh and Linux, taking as an input multiple parameters, for correctly configuring the product. The downloadable package will be a reduced version of the product, striped of multi-user or data import/export capability.
# I. Main System Components¶
In the following chapters, we intend to describe the architectural details of TVB, starting from a top level view, and going deeper in detail, as the document proceeds.
## 1. APPLICATION INTERFACES¶
The process of interacting with TVB Project needs to be smooth and easy, even for the complex user stories aimed to be solved by this project. Thus, a set of multiple interaction interfaces is to be provided, to accommodate the best support for each specific user typologies and deployment alternatives.
Based on the interaction method we can identify the following categories of users:
• Graphical User (G-User in the above figure) - As the name suggests, the Graphical User will access the application through a complex graphical interface. The interface is expected to fulfill usability standards and to have an intuitive and familiar outfit.
• Script User (S-User in figure) - This type of user will access the application through a fast, scripting interface. This interaction type is recommended for advanced users only, for which the concepts proposed by TVB are known and understood.
Based on the deployment method, we can identify the following categories of clients:
• Light Cluster Client - This type of client, will come with a minimum set of installed components on the client side, and it will intensively use the cluster infrastructure for all operations, including data storage.
• Stand Alone Client - On the opposite side of the Light Cluster Client is the Stand Alone Client. A stand alone installation, needs to be self-sufficient, to execute all TVB related operation on the client device, without communicating with the original TVB site (except maybe for regular software updates). This installation will no benefit from the cluster hardware computing power, but it will be able to work even in the absence of a network connection, and it will accomplish the most strict privacy standards.
• Stand Alone with Cluster Fallback - This third type of client, combines the advantages from the previous two ones. On the client side we have a set of capabilities installed, and for the operations which are extremely resource consuming, this client is able to communicate with the cluster. The light operations are expected to be executed on the client-side, but the longest ones will be passed to the cluster. The cluster receives abstract sets of input data, without nominal information, or even references, and only the client will be able to interpret results, thus providing a high privacy level. In the absence of a network connection, or with a low band-with, the stand alone client is still capable to execute local operations.
TVB is expected to have a dynamic interface; depending on the user’s role, group, process in role, etc. The above mentioned user categories and deployment procedures are to be closely considered when designing desired interfaces for TVB application.
## 2. BACK-END SYSTEM¶
TVB application summarizes all the logic, which enables data-sets to be:
• feed into the system;
• processed according to a configurable parameter-set;
• visualized.
An important requirement for TVB project, to be taken into account, is performance. Due to the nature of the given problem, a single simulation-step can not be easily distributed over multiple processing threads, but each simulation-step can be fully computed in a different thread, potentially on a distinct node (with special requirements on the node - mainly in terms of available Memory). However as we will have multiple simulations (with different parameter-sets) from one user on one data-set and additionally have a multi-user environment, where multiple users work on the system in parallel, the usage of a cluster would give a great advantage, by being capable to execute multiple tasks in parallel.
TVB also has to be multi-user and multi-tenant capable. The back-end component will need to fulfill this capabilities.
Strictly from a functional point of view, the Back-End is expected to transparently handle different interfaces, and fulfill mainly the same functionality, regardless the chose interface. Anyway, there are few capabilities deployment specific, like dealing with multiple data-feeds, and managing computation on a cluster.
From the implementation point of view, the Back-End system will have dynamic components packed, dependent on the chosen interface and deployment procedure. An automatic packaging tool will make sure the correct components are packed. For example, with the web interface, a web server is expected to be provide as main part of the Back-End, and on the cluster deployment, the full set of capabilities and clients are expected to be supported.
As for the stand-alone distribution, the problem gets a bit more complex, because we would definitely want to avoid duplicating modules, but reuse same components as in the cluster distribution. One straight-forward solution would be to include in the client-distribution a small web-server instance. Starting the application on the client will start the web-server, accessible from any browser, as long as all the paths in the application are relative. Another solution is to design from the start a stand-alone interface, with a non-web graphical interface, and re-use the back-end services only.
## 3. STORAGE SYSTEM(S)¶
TVB-Application will work on structured meta-data, which should be searchable and on big data-sets (which are also structured, but do not benefit from decomposing and feeding into a standard database). Thus we would need some persistence, which is structured and searchable (most probably a relational database, but it could also be an XML-File for a “local” deployment) and a shared storage for the high-volume data-sets, which needs to be accessible from every involved node (in the cluster deployment).
Where it is obvious, that design decisions around access control has to go into the DB design, to secure the data we process; it still has to be discussed, if the same applies for the File Storage, or if we secure access to files via other means (network restricted access, firewalls, etc.).
## 4. DATA CONNECTOR¶
Big data-sets of medical information already exist in multiple external data storages (used for other purposes, too). At some point in the usage of the Virtual Brain system, some of that data can be imported.
Similar in terms, but with different data-flow, is valid that data also has to leave TVB-system towards some External Data Storages. Thus the Output Data requires to be processed and exported from an internal form into an accepted external format.
Initiating a Data-Connect command will come from the Browser interface or the Console Interface, and will pass the Back-End Component, but the real executor of that job, will be the Data Connector component of the Virtual Brain.
The Data Connector is expected to receive a Job Descriptor, witch includes information about the External Data Source, credentials to access the system and operation target (what to do with the data). The meaning of the data to be imported/exported can come from the External Data Source itself, in an accepted format (metadata), or from the Back-End System.
The interface with the External Data Sources is to be established, and will be highly dependent on the target systems.
Specific transformations of the collected data can be executed on the imported data-sets, and it is part of this component’s description to do them (based on the information in the given Job Descriptor). Depending on the effective data, and taking in consideration the accepted formats for TVB internal simulation algorithms, the transformations required can be quite complex.
An alternative to this component is to have all the input data “uploaded” from the user interface, but this is a highly not desirable method, because of the size such data can have, and the frequency of the operation. Nevertheless an upload from the browser interface might be necessary, when no other external system exists and data is provided “as-it-is”.
This component is expected to be part of TVB Cluster Version, and unavailable in the Light distribution for single nodes. This is still an issue to be discussed and decided, but this proposal (of excluding this component from the light version) comes from the fact that the requirements for this component to work might make the “light version”, much too “heavy”.
# II. Second Level of Detail¶
In this second drawing, you can find the same main components as in the previous level of detail, each of them only gaining several sub-components inside.
Important at this level of detail is the coloring scheme: it tries to identify which of the components are to be distributed in the Light TVB Version and which are to remain only for TVB Full Version. The colored blocks are expected to be distributed in the Light version, but the white components will not be distributed at all (e.g. Data Connector), or will suffer great changes (like the Web Server part).
An exception from the coloring scheme is the gray block representing the External Data Storages, which is not part of TVB at all, is only used for communication with.
To identify the visualization blocks, we used the green color (for components to be distributed in the Light TVB Version) and Italic font, for other visualization blocks, available only in TVB Full Version.
## 1. APPLICATION INTERFACES¶
### A. HTML Interface¶
One of the most important requirements for the Virtual Brain project is to have a web interface. Thus a browser will be involved, and it will be the entry point in accessing the Virtual Brain Full functionality, and also in rendering this interface. The HTML Interface will be a modern and extremely usable interface to TVB.
The exact supported browser types for the application will be decided at a later point in the development flow, but it is expected to have none, or as few as possible, third-party elements installed in browser. Nevertheless, it is expected to have Java Script enabled and HTML 5 supported (including WebGL). This will split the work for visualization between the client and the back-end server, thus minimizing the network speed dependency. We do not intend to have an extremely thin client nor a fat back-end, but rather split the work between the two components, to have a mediative solution for bandwidth dependency and rendering speed.
Most user’s interaction comes from a browser interface, and also most of the processing results will be presented to the end-user in browser. Other forms of output, like “downloadable” results, are obviously necessary.
### B. Console Interface¶
It is expected, for The Virtual Brain project, to have a special type of users, working on a very low level of abstraction, and for that, they will need and use a console interface. These users, will probably be researchers, with a previous neuroscience knowledge. They will benefit of full control over the internal parameters, flow and algorithms. Obviously, the Console Interface is harder to use, by a non-initiated user, but manuals will be provided, along with examples of extensions, and workflows.
From the two categories of users expected for TVB: “G-user” (Graphical User) and “S-User” (Script User), defined in Chapter I of this document, the Console Interface will serve S-Users. S-Users, are initiated users, who need a lot of freedom and speed in the actions they are to do with TVB, and the Console Interface intends to support that.
### C. Stand-Alone Client¶
A third type of interface, the Stand-Alone one, comes from a specific distribution scheme: stand-alone distribution, not in cluster, but installed on a personal/local computer/laptop.
The Stand-Alone Client needs to re-use all the back-end business logic that is used by the other Application Interfaces, and only re-write the View Component (from Model-View-Controller Design Pattern).
This Interface comes with a specific requirement support: extending TVB functionality with custom algorithms or plug-ins. It is highly risky to allow contributors to append custom components directly in the cluster public distribution, thus, the Stand-Alone Client comes as a safe solution. Also for network connections with very low speed, the stand-alone client will provide an elegant solution, by avoiding long waiting times for server responses.*
## 2. BACK-END SYSTEM¶
### A. Web Server Application¶
The Web Server Application is the controlling element at the back-end level, for the HTML Interface. It should be the one receiving data from the HTML Interface and making sure the correct response is feed back, after corresponding operations were executed.
It needs to take into account the need of having the UI decomposed into several parts (for easy maintenance and development) and possibly also the requirement to have a light version of the software deployable on a single personal computer (with a wrapped web-server on the client).
Also at this level, visualization parameters and input data will be prepared, for usage at the HTML Interface level, and for passing it to the back-end components, respectively.
### B. Framework & Flow Manager¶
As the Web Server, will be used for the HTML Interface only, and possibly only for the Full TVB Distribution, the Framework Flow Manager is the intersection point between different Application Interfaces and the actual business logic in the Back-End. Thus this component needs to be abstract and have no connection with the interaction method (script, html or stand-alone interface). This component need to act as a framework controller for TVB business logic and also have some flow management.
The next four components in Back-End (Uploading Adapter, Simulator, Data Analyzer and Visualizer), are all part of TVB specific workflow, implementing TVB specific functional requirements, but the Framework Manager will be an abstract package, managing different types of operations (not only TVB specific ones).
We expect this block to be the common point in interacting with TVB libraries (the four mentioned above) or other custom libraries (sharing the same interfaces), from the Web Interface and Stand-Alone Client (by the G-User) and from the Console Interface (by the S-User).
From the development point if view, the Flow and Framework Manager will have a triple role:
• recording user’s action and their results, for logging purposes or playback;
• playing a sequence of operations, from a previously recorded set of actions or deduced/parsed from current user’s input;
• and offer code support for the Application Interfaces and the Independent Plug-able Libraries.
This component will be the one controlling the interaction jobs into the Data Connector component, as it will trigger and configure such IO operations, and will receive feedback about them.
Along with retrieving or exporting data in the background, from or into External Data Storages, we will want to have also data uploaded directly from the Application Interfaces. This will be data obtained from patient scans and needs to respect a well defined format. The Upload Component will take care that the correct format is followed and data is stored in the correct places.
The Uploading block is directly controlled by the Flow Manager, but it further controls the Data Connector block.
### D. Simulation Component¶
The Simulation Component is probably the most representative component in The Virtual Brain solution, as it is the component responsible for all the scientific computation related to brain models and data.
The Simulation Component will receive controlling messages (a set of parameters) from the Flow Manager, and will know how to retrieve required Brain- Input data from the Storage System (set of input data to work on), based on that input.
The Simulation Component, along with the Data Analyzer Component, will benefit of the power of a cluster, to have their operations asynchronously executed there, as fast as possible. The problem structure of the Virtual Brain project, as we know it for now, seems to be hard to paralyze (the sequential flow of steps for data preparation and simulation is highly interconnected). Thus, when splitting work over multiple stations, the main nodes in our structure will be used to execute unitary and mostly independent processing steps.
### E. Data Analyzer Component¶
For brain related data, several Analyzer algorithms are currently available to “process” the results.
It is known that most data analysis approaches are still “work in progress”, thus TVB should allow for the greatest possible flexibility on the side of the S-User when it comes to any kind of data analysis algorithm. This being the case, TVB should allow for the user to adapt his/her own analysis tools.
The above mention issue is another common element between the Simulation and the Analysis Components. The S-User will be able to create and/or configure his/hers own processing algorithms to be executed. The S-User will be provided with hook-points for creating custom block to fit into TVB framework; in the same time, configuring the equations is also expected. The G-User is limited to the available algorithms inside TVB, but configuring them should be possible, too.
As S-User enhancements are visible only in the local environment (TVB Light Version), malicious code is avoided in the public distribution. Integrating contributor’s work into the public TVB distribution will be manually handled, by authorized personnel. In a next generation of TVB we could provide the capability to upload code directly into the cluster distribution. In such case, we will make the new code “invisible” for most of the users, but available only to the owner, until some authorized person checks the new functionality.
### F. Visualization Back-End¶
The visualization tools are critical for TVB -they are difficult to home-brew and can really provide a quantum jump in understanding the neuroscience “secrets”.
TVB should provide the capability to visualize, possibly as a movie, and where aplicable rendered in 3D, the following generic data types:
• scalp based data (EEG, MEG);
• cortical surface data (MODEL, SEEG);
• volume based data (fMRI, lesion site): visualization as a movie of selected sources with the brain as a background.
Several data types are expected to be supported for visualization. Acknowledging the fact that data types are extremely different, in form and meaning, a different visualization library is expected to be needed for each such data type. For sure, common part are expected, also.
From the specific visualization requirements that TVB has, based on neuroscience formats and protocols, we spot:
• visualization of connectivity matrices (structural and functional connectivity);
• visualization for the Connectome proposed data formats (NIFTI, GIFTI, GraphML, TrackVis);
• display of multiple time series with possibility to let it shift through (as known from EEG) for arbitrary sources, nodes, electrodes.
• display of wave let time series with possibility to let it shift through (as known from EEG) for arbitrary sources, nodes, electrodes.
• power spectrum for time series of arbitrary sources, nodes, electrodes;
• frequency-time plot of arbitrary sources, nodes, electrodes;
• coherence matrix of arbitrary sources, nodes, electrodes.
The Visualization components are highly dependent on the exact Application Interface chosen, thus an important part of the visualization is located in the Interface blocks, but we are expected to have a common Back-End, for using transparently any interface, dependent on the user chosen distribution.
### G. Data Types¶
The Upload, Simulator, Analyzation and Visualization Components will need to have a common “language” in order to work with the same data. In TVB architecture, that “common language” is represented by Data Types.
A specific Data Type X will be generated after and upload operation from the interface, Type X is accepted by a Simulation Model as input, and it generated Type Y of Data. Type Y is accepted by an Analysis algorithm, and both Type X and Y have Visualization mechanisms. This is an abstract example of how Data Type can be used, for linking structures between different components in the Back-End block.
## 3. STORAGE SYSTEMS¶
Sub-components for the Storage are: Database(s) and File System(s). One of these two elements could be used exclusively, but a complementary solution is considered better. Different distributions (Cluster or Stand-Alone) might have differences in the way data is stored.
Few distinct data collections are to be stored and later on manipulated in TVB project. Some of them will support mixing, but for others might come more natural and safer to be stored separately (distinct structures and different physical locations).
On one hand we will need to store application data: users, roles, groups, simulations progress state, personal input data and associations, settings, results mappings, work progress. This is the data coming from the Web Server Application and Framework Flow Manager, and it will be used by them when composing the final content for the UI-pages. This data is expected to be stored in a relational database system, as it would make use of the organization and the search engine of such a system.
All the cluster-related data needs to be stored someplace (probably database, but also xml files might work). It will refer to cluster nodes configurations, status, role, updates, etc. This data will come from the Cluster Manager component and will be used by the Cluster Job Scheduler when distributing tasks over the Simulation nodes.
On the other hand, there is plenty of brain-related data: brain models, 3D structures, EEG measurements, MRI, etc. This data will enter the system through the Data Connector and Uploading Adapter components, but needs to be available for access to the end-user (when controlling the simulation flows), and will be highly accessed by the Simulation, Analysis and Visualization Components, as input data. It is to be decided at the development time, for each data set in particular, which sets are suitable for relational database storage and which for file systems storage. Currently, DB indexed references, combined with a file storage for the actual neuro-data is the chosen solution or implementation.
Also the simulation and analysis results will require storage. This output data is similar with the uploaded data, so it will have the same storage mechanism as mentioned above.
To summarize the storage needs for TVB, we will store:
• processed data (end operation or intermediate results);
• references of operations that have been executed or are planed for execution (not the actual script, but an algorithm link), so the flow of operations can be reconstructed from those.
OPEN QUESTION: We mentioned the cluster-distributed form of the back-end components (Simulation and Data Analysis). How can we design the Storage, so that the cluster won’t have a bottleneck in executing parallel tasks while accessing the Data Storage? All operations will need to, firstly, read data from the Storages (Brain Models, Measurements files, etc.); in the same time, we will have the streams of results from several nodes to be written in files, maybe on a common disk. Is it enough to leave this parallel writing job to the hardware and the parallel reading to the DB management system?
The hardware should do the job (when writing different files in parallel - big files with results), the DB access time for committing results references should be small enough not to create problems, and the DB system should be fine with parallel reading, but we also need to provide mechanisms for job scheduling and resources locking, to avoid problems.
### A. Database(s)¶
We refer here both to regular Relational Database installations, but also Relational Database clusters are acceptable, depending on the physical resources and the performance or highly-availability requirements of the project.
Some tables in DB will be generic for the Framework structure that we provide, and other are highly dependent on TVB specific operations. We are to separate these two, only at the business level, and have the Framework structure independent from TVB Data, but we will use the same storage database for all.
In the relational DB we store: informations about users, projects, references to algorithms (that can be executed), operations (with their status, input parameters and results-references) and data-links.
### B. File System(s)¶
A File System is a suitable solution for when we want to avoid several problem that Blobs in most of the Relational DataBase Systems have.
In the File Storage we store actual neuro-data (uploaded files and operation results). The file storage is a Tree of folders and files. The files in the storage are of two types:
• data-files (actual neuro-data) or
• metadata-xml files (files generated and used by TVB application, invisible to the end-user in the interface). These files can be of use for us, in generating multiple forms of storage for the end-user (e.g. do not display it as a Tree, but make a flat list or a graph from it).
Also in the xml-files we will have support for the following tags:
• Functional Data type (e.g. EEG. Connectivity Matrix, MRI Data, etc);
• Subject of Group Identifier (and maybe a second field isGroup = True/False);
• Source of data (simulated or real);
• Processing step (normalized, preprocessed, etc.);
• File Type (txt, binary);
• Experiment Date/Interval.
## 4. DATA CONNECTOR¶
### A. Connector Core¶
The Data Connector component will be the link of Virtual Brain with other External Data Provider Systems, and the Connector Core is the coordinative part of it.
The Connector Core will receive the External Source address and credentials from the Uploading Adapter, along with an optional data description and will execute all required jobs to retrieve data from the External System and feed it into TVB system, or export it from TVB into External Storages.
Several protocols are expected to be supported, for connecting with the External Storages: SOAP, FTP, SSH, HTTP, or maybe simple DB connector. Depending on the External Source descriptor, one of the supported protocols will be chosen for communication.
### B. Pre/Post Processors¶
After importing data sets from an external data store, and before actually using that data into the system, several data-format transformations might be required (pre-processing). Also, before exporting data from TVB towards some external storage, some data post-processing steps might be required.
We know the structure for the data to be imported/exported, from the external data source metadata, or from the web-application’s initial job description; a set of user configuration are possible, to interfere into the processing flow. The pre and post processor elements will consider all the above and choose the correct algorithms to be executed. The jobs in these processing flows are similar to a single simulation-run, thus can run on an arbitrary Cluster-node.
The logical difference between the pre-processor component an the post-processing block, is that while the first component prepares data before using it into TVB system, the second one prepares data after internal TVB processing and before exporting it into External storages.
# III. Third Level of Detail¶
At this level of detail, we can distinct what TVB Framework means. As mentioned in the Legend area of the document, TVB framework is the architectural structure, along with the implementation artifacts that allow plugging-in independent libraries into this framework. Looking carefully at the above drawing, TVB Framework represents all the blocks present there, except for the blue bordered ones (which are the independent libraries, plugged into the framework).
In the above drawing, the components were primary classified based on functionality (User Interface vs. Back-en Services, Simulation vs. Visualization). The separation into TVB Framework and Independent Components, on the other hand, is based on development procedure, because we want to have a Framework generic, and plugged components possible to be developed by different teams.
An Independent Library is a simulation or analysis algorithm or even a specific visualization tool. In current context, a Simulation Independent Algorithm means: the minimal set of programs to run the virtual brain model in scripted fashion (not even bothering with an interface), on your favorite Laptop. The Framework can further be used, to link from Simulations to Visualizations or Data Analysis.
## 1. APPLICATION INTERFACES¶
### A. HTML Interface¶
A browser itself is not intended to be implemented in The Virtual Brain project, but several TVB sub-components are expected to work directly with and reside inside an existent browser instance. These sub-components will live inside the browser, and mostly will be JS and HTML based.
As TVB interface is expected to be a non-trivial issue, it is a good idea to decompose it into several smaller components. In this direction, the UI-Extensions are a possible solution.
The UI-Extension, proposed term, is close to the Portlet concept, but for now we do not want to fix architectural decisions, but to cut out functional blocks. Portlets (or similar concepts) are used for big web-applications, because they bring extensibility and flexibility in the UI and core functionality of a big and configurable application.
As a multi-user application, each user will have his/hers personal needs of composing a personal useful view over the system. The smaller the UI components are, the easier a configuration will be. Also, regarding different situations, each UI-Extension can have a different view, considering current logged user, current data to display and its role, settings, or status. These will be HTML generic extensions, part of TVB Framework.
Another type of extensions, are the HTML Adapters to TVB specific visualization needs, for displaying specific TVB Data Types in the HTML Interface. These adapters are not part of TVB Framework, but are treated as Independent Libraries, because they have a specific form (for easy management from TVB Framework), but are specific to TVB functionality (not part of the framework).
Every HTML Adapter, which plugs-in new functionality, has to use the UI TVB Framework to interact with the back-end. Also a need can be foreseen, to synchronize actions between adapters (e.g. one could think of a general Inspector-Component, which needs to adapt to chosen elements).
Each adapter should provide complete and sound functionality. One adapter can depend on the TVB UI Framework, but it is not desirable to depend on other Adapters.
Extension’s content displayed to a user in browser, is a result of deployed back-end blocks (e.g. HTML Visualization Adapters), and the architectural rules for describing the extension’s code will reside on the back-end system (Web Server). Having the user interface supporting multiple extensions will bring a higher complexity degree to the overall system, but it should be a price worth paying for.
HTML Adapters will provide the actual content, but for rendering that content, some already defined tools will be used (browser, renderers).
#### A2. TVB Data Renderer¶
Plenty of visual effects and high level user interaction are expected to be part of TVB’s footprint. In this architectural level, the tools capable of composing such a complex user graphical interface, are called generically: TVB Data Renderer(s).
Some of the renderers will be fat, like the ones including Java Script code, to be executed on the client side, while others will be extremely simple, like displaying a simple image. All the browser’s capabilities are to be exploited here (as long a they match TVB license): HTML5, JS, WebGL, and even Flash or Applet, in case we are to include already existent solution.
#### A3. UI Framework¶
UI Framework will act like a generic component, were multiple UI Extensions are plugged. UI Framework will contain common handles (e.g. handler for mouse or keyboard interaction; generic Zoom functionality on Canvas), to be used in multiple HTML View Adapters. The UI Framework component should provide support for application extensibility. By having well established interfaces and abstract communication/control functions, it should be able to adjust to any extension needed in the future.
The UI Framework is the master for all the background processes on the client side. For sure the user is the initiator of any action, but the Framework component is the one acting asynchronously or synchronously, behind the scene, to trigger some UI data receiver. and coordinate different HTML Adapters.
### B. Console Interface¶
Implementing a raw Console is not what we had in mind for this component, we only intend to provide a command-line front-end for TVB.
This component, along with all the S-User capabilities, are expected to be available only in TVB Light distribution version, at least for the first version of the product. In a future version, the S-User might be included as part of the TVB public cluster distribution, also.
The S-User will start the Console Interface by executing a TVB file in a classical console on his/hers preferred operating system. This action will place the user in a command/text interaction with the system. The Input Reader block will be used for getting the user’s commands, and transmitting them to the next component in the data-flow: Parser.
#### B2. Parser¶
A trivial parser will be needed, to understand several hard-coded commands, accepted by TVB console interface. The exact supported commands are to be established when the simulation and data analysis libraries are ready.
A possible implementation for the Console Interface will be with the Python programming language. In this case, the Input Reader and the Parser are nothing more than a set of methods and functions in Python that are available for call. A precondition will be to have Python installed, and the supported Operating Systems are the ones supporting Python.
When having the command parsed and thus understood, one must translate it into TVB compatible language (internal existing method names to be called). The role of Script-Adapter, is to establish the correspondence between parsed items from the user’s input and internal TVB language.
The S-Adapter will directly communicate with the TVB Flow Manager and have a command ready in a format accepted by the later. In TVB language this will mean, the S-Adapter is sending a sequence of steps to be played by the Simulator or Data Analyzer. The S-Adapter will sent towards the Flow Manager a sequence of steps in the format that you will find exemplified in a future level of details, under the Flow component.
#### B4. Result Displayer¶
The Result Displayer component will take care of two types of feedback, to be displayed to the user:
• When long time operations are in course, a visual feedback is needed to be sent to the user, constantly.
• When operations are finished, the user needs to be notified. In case results are Console-compatible (e.g. single numeric values), they will be immediately displayed. In case other types of results are present, the user needs to be pointed to the location where the files with results are placed.
### C. Stand Alone Client¶
The structure inside Stand Alone Client is standard for a user interaction package, it contains Controllers, Screens and View Adapters.
UI Controllers and UI Screens are the Control and respectively View, parts from the MVC Design Pattern. The Model block, is the same as the one used in the rest of the user-interfaces, and it is located in the Back-End component, in TVB Framework.
View Adapters are specific TVB visualization components. They will inherit, like the rest of Adapters, from the Abstract Adapter, and being Adapters for Visualization purpose, will also have a common logic (common for all Application Interfaces) in the Visualization Back-End component.
## 2. BACK-END SYSTEM¶
### A. Web Server Application¶
As mentioned before, a Web Application is to be deployed in a Web Server Container and it will be the logical leading element, from back-end, for the HTML Interface.
It is expected from this Web Application to provide the HTML pages (as templates with place-holders for business entities) and the corresponding Controlling components for them. From MVC Design Pattern, the Model will be re-used, common for all the three interfaces, and taken from the Core Services.
### B. Framework & Flow Manager¶
This component has as major roles:
• to manage the flow of operations in TVB;
• to offer a skeleton of code, for contributors to re-use easily and implement custom but intractable algorithms based on that skeleton.
#### B1. Flow Manager¶
The Flow Management layer has a complex set of roles for himself:
• to configure a TVB workflow with parameters and input data;
• to play a sequence of internal operations;
• and to record sequences of executed actions with their results.
For each of the main operations enumerated above, a sub-component will appear at the next level of details.
#### B2. Framework Core¶
The rest of the components inside Framework & Flow Manager, except the Flow Manager, all represent the Framework Core.
The Database Interface component is self-explanatory, by name. It will not be used directly from outside this block, but used indirectly, through the Core Services.
Application Core Services contains several algorithms and procedures, commonly used by the Web Application and the rest of the Application Interfaces. Here we will find actual “service” classes, along with the application database interaction control.
The Cluster Controller block should:
• distribute tasks over the nodes in cluster;
• schedule TVB specific jobs;
• and make sure the results and input data are retrieved in the correct order and from the correct place for each job.
We have other two block here: the Abstract Adapter and the Abstract Data Type.
One of the most important requirement for TVB is to have the Simulation, Data Analysis and Visualization libraries independent, in the sense of being possible to use then as stand-alone component, from a Python Console, for example, or imported in another project. But when included in TVB, we will want to design the interaction with such independent libraries in a generic way.
A generic Abstract Adapter and an Abstract Data Type can be imagined to be used between TVB core and such independent libraries, with exact implementations of this abstract components, dependent on the exact library. In TVB components, we will use dependencies on this Abstract classes, but at run-time, instances of the concrete implementations will be created and used.
The Abstract Adapter is the interface for integrating the actual algorithm (from simulator, analyzer or visualizer) and the Abstract Data Type is the interface for the entities that will be passed between such Independent Libraries.
The IO Controller will coordinate the Input/Output operations into TVB. It will control the Import or Export with the Data Connector, or the local imports by uploading into the interface.
The Upload Adapters are concrete implementations for the Abstract Adapter. They have the purpose to accommodate, each of them the integration into the system for one specific Data Type. Not all Data Types will need to have an Upload Adapter, because some Data Types are introduced into the system as results of specific operations, like running a Simulation.
### D. Simulation Component¶
#### D1. TVB Simulation Library¶
This component should model the sequential computational steps for a single simulation run, with a single parameters set on a single data set.
This library is also called a Simulation Core, because it is a package, which most bare-bones all you need to make a TVB-simulation on your laptop. This component is expected to be independent, thus capable to be used from a Python Command line, without any other TVB interference.
TVB Simulation Core will certainly be part of the TVB Light Version, and although a simulation could be executed with only this package, in case we want a fancy command-line interface, a job scheduling executor, to configure the input parameters, even in the single-node installation, we will need functional elements which are found in the rest of TVB Framework.
These adapters will link the Simulation Library with TVB Framework. They are concrete implementation of the Abstract Adapter, specific for communicating with TVB Simulation Library. By having multiple Model Adapters, we can accommodate into the simulation library several Modeling algorithm for the brain, with different set of parameters accepted as input.
### E. Data Analyzer Component¶
Similar to the Simulation Component, the Data Analyzer contains concrete implementations of the Abstract Adapter. Common algorithms or tools between different such Analyzers are expected to be hold in a package named Core Analyze.
The Analyzer Adapters, should be built as independent components, probably implemented by different persons. The libraries will need to be aware of the purpose of being used with TVB framework, but they will not depend, when built, on other TVB components.
### F. Visualization Back-End¶
The Visualization Back-End holds the common visualization tools, used by different Application Interfaces. This package shall store at least an abstract extension of the Abstract Adapter, named Abstract Displayer, with common part for all Visualization Extensions.
### G. Data Types¶
Data Types represent the common entities used by Uploaders, Simulators, Analyzers and Visualizers, they offer a well defined structure for the data to interchange. All Data Types will inherit from Abstract Data Type in Framework Flow Manager.
Each Data Type defined, can produce a table in the default Storage System. This table is recommended to be used for storing short amount of data, and use the File Storage for huge amount of data.
## 3. STORAGE SYSTEMS¶
This component remains unchanged from the upper level.
## 4. DATA CONNECTOR¶
### A. Connector Core¶
We propose a division of this component by using a double Factory Design Pattern.
#### A1. Connector Factory¶
This Factory is the entry point into the Data Connector component. It will receive the Job Command (What type of job it is; which is the address of the External Storage to connect to; What are the credentials; What data to expect or put there), and it will make sure, based on that, to choose the correct Connector instance for being created.
#### A2. Processor Factory¶
This component will have a double role:
• firstly will be the instance creator and initiator for the Pre/Post Processor effective implementations;
• secondly and equally important, will make possible Processors initialization and/or chaining (in case a previous configuration exists.
From an implementation point of view, this Factory will, most probably, not return a single object Abstract Processor, but a list of such instances, representing the processing steps to be executed on data before exporting it from, or after importing it into TVB.
#### A3. Abstract Remote Connector¶
A common and generic structure for all connector will be contained in this component.
This abstract connector, along with all its implementation connectors will depend on Abstract Processors, to be called before or after exporting or importing data.
#### A4. Concrete Remote Connector(R.C.)¶
Depending on the exact protocol to be used when communicating with the External Storage, different concrete connectors are expected to be written.
Examples of connectors expected to be needed are: SSH Connector, FTP Connector, SOAP Connector for web service enabled storages, Relational Database Connector for simple DB storages.
### B. Abstract Processor¶
A common structure for a Pre or Post Processor is defined through this component. This abstract block will be the one used when defining dependencies from other components to Processors, but at runtime, concrete implementation of processors will be used.
### C. Pre/Post Processors¶
Pre or Port Processor components are implementations of the Abstract Processor block described above. Different concrete implementations of processors are expected, because the data in External Storages will take different formats. Depending on the Storage internal formats, a specific processor might be needed to be implemented.
These data processing components will have two main sub-components internally: firstly a Stream Reader, and secondly the exact Algorithm to be executed.
Both the Pre and Post processors will have a similar structure, only different algorithms and step in the work-flow when to be used.
# IV. Forth Level of Detail¶
Current Forth Level of Detail intends to underline the main, sometimes different, flows through the application: Data Flow and Control Flow. The two different flows are drawn with two different types of lines (dotted or continuum). Several other types of links between components are spotted in this drawing, with the accepted UML specification (aggregation, inheritance, dependency).
Some of the components that did not gained new details, and remained unchanged from previous level, are drawn as white boxes.
Colors in the names of the modules, were used only to spot similarity (e.g Data Connector and Data Connector Controller, both have the same color because they fit together, from the functional point of view, and they directly communicate).
The previous drawings does not include IO elements, to make the entire picture readable, but in the drawing below, some blocks got fewer sub-components, and the IO elements were included. Both drawings (previous one and next one) are at the same level of detail, they should complete each other.
## 1. APPLICATION INTERFACES¶
This component is mostly unchanged from the upper level, except for a few new sub-components, described bellow.
### A. HTML Interface¶
Data Reader is a sub-component residing inside some of the HTML Adapters. UI data streams will come from the Back-End system and it is the Data-Reader’s role to feed that data for visualization to the Adapters.
The Data-Reader mainly is needed for queuing, but also client transformation modules can be plugged in here, in case any will be needed and we decide that we want to translate some of the work from the Back-End towards the client side.
This component can receive triggers from the Command Adapter, will react to data streams received, and the right data-listener in the UI can easily be parametrized to take over the correct visualization data.
#### A2.1 WebGL Renderer¶
A WebGL renderer is needed for the 3D objects to be displayed and manipulated by the client, on his local machine.
WebGL is a generic interface, with specific implementations provided by each particular browser. Not all browsers provide WebGL support, and not all graphic cards support WebGL. Each client must have an OpenGL 2.0 compatible graphics card and a browser installation with WebGL enabled, in order to take benefit of the full TVB visualization capability. It is not planned, to have any local render-alternative (e.g. some Flash or Java Renderer) if the client does not meet the WebGL-requirements.
The exact data to be rendered by this component, comes from the UI components of TVB site (HTML Adapter), but not all such components are expected to have WebGL code.
A WebGL rendering component can have its input data updated asynchronously, by some software component behind the scene (call server to compute new objects coordinates), but it can also auto-sustain some visual updates to be computed locally (user rotating an object, changing the light sources, adding shadows in a 3D world of objects, etc).
Especially this component moves some work from the back-end to the client. WebGL is Java Script code, executed in the client’s browser and connected directly to the local graphical card.
#### A2.2 Graph Renderer¶
As WebGL Renderer component described above is expected to be used with 3D objects, the Graph Renderer block will handle 2D plots to be correctly displayed. Currently we can see two alternatives for this: one is to use JS based libraries for 2D plots, and the second one is to have a back-end for Matplotlib in HTML. Both alternatives have advantages and disadvantages, thus we might end-up using both, for different graphs.
#### A2.3 X Renderer¶
Depending on the exact Visualization Data, these two Renderers presented above, might need to be backed-up with other similar components, for distinct data-types. In the abode architectural drawing, such a component was called X Renderer.
We could consider also the possibility that not all users have WebGL capability, or they might want to disable client work, when lacking of local computational resources. In such cases, the back-end could provide a specific Visualizer, that will render on the server side several images to be feed to the client, and displayed in a simple Rendering component (different than the WebGL Renderer; in previous drawing present also under the name X Renderer). In this case, the network connectivity will be highly used, and most probably the quality of the visualizer will not be the same (e.g. no possibility to rotate the image in real-time).
Besides the 3D or 2D images and movie renderers, one other special renderer needs to be present for allowing users to interact with the Workflow Manager (drawing states, linking them, configuring, etc); this type of renderer is also hidden under the X Renderer abstract umbrella.
The Command Adapter is used to transport user interaction from the UI components down to the back-end Web Server. Its main target is to control the UI Extension components with commands coming from the Back-End, but it can also be used, to transport feedback to the Virtual Brain Back-End.
## 2. BACK-END SYSTEM¶
### A. Web Server Application¶
At this level of details, the Web Application got a roughly package structure. The packages presented here were identified on functional criteria, and for sure, at the implementation level, each will split into two of three implementation sub-packages, but from the architectural point of view, these should be enough.
An important package present here, is the Web Visual Adapter. Along with the Results Integrator component from the Visualization Component, this package should be responsible for feeding the Visualization Data Streams, produced by the Visualization libraries, into the Browser component, that will render them to the user.
### B. Framework & Flow Manager¶
This component remains the same as in the previous layer, only the Flow Manager block got few sub-components.
#### B1. Flow Manager¶
A Flow Editor is required, to allow greater flexibility in the sequence of operations to be executed, by configuring steps. A Player will come next in role, to read the flow and transform it into exact operations to be executed by the correct execution block.
The Recorder is the component responsible for logging into an internal format all the action a given user does, along with the action results. When recording user’s actions and results we need to make sure several previous established rules are met, especially related to occupied space. In this way, the Recorder will provide a mechanism for caching. The Player needs to have a special care when playing actions, to check if previous results are not already computed, and to avoid re-computing results that are already in place, but rather return previous recorded data, to enhance performance.
The same format that a Player accepts, for identifying actions to be executed, will be known by the Recorder (to record actions in that format), and by the Console Component or Web Application (to encode users input into this internal format).
A proposed form for encoding the sequence of action, is:
<sequence name="Custom Name">
<step name="Step1" component="SIMULATOR">
<param type="INPUT_DATA">
<reference value="ID_BRAIN_DATA"/>
</param>
<param type="INPUT_PARAM">
<equation value="Custom Value"/>
</param>
<result type="FILE" path="C://data"/>
</step>
<step name="Step2" component="ANALYSER">
...
</step>
...
<step name="StepX" component="VISUALIZER">
...
</step>
</sequence>
Several variables could be added in this format:
• Language element to symbolize repetition (e.g. for, while) will be useful in case we want to describe an operation that needs to be repeated on a list of similar data sets.
• Parameters, to be computed at runtime: current date, current user, etc.
### C. Simulator Component¶
#### C1. TVB Simulation Library¶
The Simulation library will have, along with the obvious Mathematical component, and Processing Algorithms for simulations, also a Pre-processing component, to optionally prepare data before simulations.
#### C2. Simulation Component¶
The Simulation Cluster Integrator component will deal with highlighting how the jobs to be spread over the cluster. In case current version of the software is not distributed in cluster, this block will be skipped from the data-controll-flow, as all jobs will be executed on a single node. This is the reason why this component appears as a white box (inactive or not present in the Light TVB Version).
A generic Flow Controller could also be present here. Simulations are complex operations as they are, but also multiple users will want to operate on multiple input data sets, thus complicating things even more. A Controller, using some Jobs Queue and scheduling, aims to solve this complex issue.
### D. Analyzer Component¶
Looking at the horizontal view of this component, in the image immediately above, we will notice a hook-point in the system, allowing researchers to easily contribute to the project, or to customize the system to match their needs, without needing to break into the code and change already existent code (that is also possible, but not desirable).
In order for a contributing-researcher to extend the system with a new independent Analysis Library, he/she will add a new DA Adapter, extending the Abstract Adapter, where the new Library will be called. In the next level of detail, you might see slices of pseudo-code in this direction.
The newly created Adapter will be easily integrated and presented to the Flow Control component (which will act as a Factory for such Adapters), through a settings file, specified by name.
#### D1. Analysis Library¶
Each Analyzation Library will, most probably have a specific and different structure, but a generic structure is spotted in current TVB level of detail: Pre-processor, Mathematical Library, and Analysis Algorithm.
#### D2. Analyzer Controller¶
The analysis processes are expected to be executed in cluster, along with the Simulation operations. This is why, a similar controlling structure, as the one for the Simulations, is found also in the Analyzer Controller. Preparing jobs to be executed in cluster will be similar for both simulation and data analysis jobs, this is the reason why an abstract Generic Cluster Integrator component is present, inherited inside both the Simulator and the Analyzer.
From the Cluster Integrator’s inside job, we’ve spotted the main call idea in the pseudo-code below:
for d in data_array
for p in parameters_sets
write_in_file("simulation.py", "execute_simulation(p,d)")
execute_command("qsub -1 other=simulation simulation.py")
Flow Control component is expected to choose the correct Analyze Library to be invoked, based on what user’s selected in the configurable Work-Flow, on Input Data or on some other constraints.
### E. Visualization Component¶
We have multiple data types to visualize. As these types are also extremely different in content, a proposed implementation schema is presented in the previous drawing (horizontal view). In most of the siuations is not a good idea to do things independently, but as the visualization data formats are extremly different, the proposed architecture seems the correct one.
#### E1. Visualization Library¶
The Pre-Processing component will operate on simulation/data analysis results, to make data ready to be visualized. Depending on the exact input data available, several operations will be applied:
• Split the brain surface into smaller pieces, to make the arrays compatible with a given technology;
• Change sampling rate for better performance or to get more details;
• Filter Data (e.g. by frequency);
• Re-referencing data (by changing the reference point), etc.
On the other hand, the Port-Processor will operate on the visual result, to make performance adjustments, based on exact system needs. For example:
• A post-processing step is to have the data zipped, before set to the client;
• Security issues might be applied here, also.
#### E2. Visualization Controller¶
The Library Chooser component will take care to automatically determine the correct Visualization Library to be used, depending on the Input data and Exact Job description that it received. This block is the first one, from the Visualization Component, in the Command Flow; it will determine the next concrete step to be executed. The Library Chooser will act as a Factory, by determining the correct Adapter to be called.
The last step in the Visualization Data Flow, residing inside the Controller, is executed by the Result Integrator component. This block will be responsible to prepare data for being displayed to the user. It will receive data artifacts from the Visualization Libraries, and it will make sure they are passed, in an unitary mode, to the Web Server Application (exactly to sub-component Web Visual Adapter) and later on feed into the Browser.
## 3. STORAGE SYSTEM¶
This component remains unchanged from the upper level.
## 4. DATA CONNECTOR¶
This component remains unchanged from the upper level.
# V. Fifth Level of Detail¶
## 1. APPLICATION INTERFACES¶
This component remains unchanged from the upper level.
## 2. BACK-END SYSTEM¶
Consider the Interface Abstract Stream Writer defined inside this block, with the methods enumerated below (in a pseudo-form of pseudo-code):
Interface AbstractStreamWriter:
public void write(Object data);
public void commit();
public Boolean isCompleteWritten();
The File Stream Writer component is a default implementation of the interface Abstract Stream Writer; it is expected to store the data received as parameter inside a file, specified by its path from an upper level.
### D1. TVB Simulation Library¶
For Simulation Library, as entry point to the library functions, we could have a code skeleton similar to the following pseudo-code:
import AbstractStreamWriter;
public executionStart(BrainData params, AbstractStreamWriter writer) {
while(simulation_not_finished) {
define String partialData;
partialData = executeSimulationStepX(params);
writer.write(partialData);
}
writer.commit();
}
The code slice from above does not overrules the independence principle that TVB Simulation Library has. From the code we can spot that TVB Simulation Library depends on the interface Abstract Stream Writer. Depending on an Interface it only means that the library is TVB linkable, and it can still be used without the entire TVB framework.
The Specific Stream Writer, implementation of Abstract Stream Writer, could have a code similar to the pseudo-code bellow:
import AbstractStreamWriter;
class SpecificStreamWriter implements AbstractStreamWriter {
private attribute Boolean isComplete = False;
}
public void write(Object data) {
}
public void commit() {
define Result result;
result = new Result("Simulation Finished!", resultAddress);
Session.commitToDB(result);
isComplete = True;
}
public Boolean isCompleteWritten() {
return isComplete;
}
}
From the Library Invoker‘s code:
import TVBSimulationLibrary as TVB_SL;
define AbstractStreamWriter writer;
writer = new SpecificStreamWriter();
define BrainData inputParams;
TVB_SL.executionStart(inputParams, writer);
define Result result;
result = new Result("Simulation Lauched", myCustomResultAddress);
Session.commitToDB(result);
return result;
}
In case TVB Simulation Library is to be used in another context (outside TVB framework), a possible invocation code will be similar to the one presented above, but instead of using an instance of SpecificStreamWriter, one can use FileStreamWriter, another default implementation or a custom created implementation of the interface**AbstractStreamWriter**, which will be embedded into the Library distribution.
### E. Data Analyzer Component¶
For the Analyzer Adapter and Data Analysis Libraries, a similar structure to the ones in the Visualization Component are expected to appear. Anyway, there might already exist implemented libraries, that do not support integrating the AbstractStreamWriter reference inside, for streaming the results. In such cases, or other cases when streaming is not wanted (e.g. when results are extremely short), one can consider the code skeleton bellow:
import AbstractStreamWriter;
import MyExistentLibrary as LIB
class MyLibraryWrapper {
public executionStart(BrainData params, AbstractStreamWriter writer) {
define Object wholeResult;
wholeResult = LIB.execute(params);
writer.write(wholeResult);
writer.commit();
}
}
## 3. STORAGE SYSTEM¶
This component remains unchanged from the upper level.
## 4. DATA CONNECTOR¶
This component remains unchanged from the upper level.
# References¶
1. Connectome Project.
2. EEGLAB.
|
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|
https://bibbase.org/network/publication/trifa-guinard-mayer-leveragingthewebforadistributedlocationawareinfrastructurefortherealworld
|
Leveraging the Web for a Distributed Location-aware Infrastructure for the Real World. Trifa, V.; Guinard, D.; and Mayer, S. In pages 381-400.
@incollection{ tri11,
crossref = {rest2011},
author = {Vlad Trifa and Dominique Guinard and Simon Mayer},
title = {Leveraging the Web for a Distributed Location-aware Infrastructure for the Real World},
pages = {381-400}
}
|
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|
https://www.balena.io/blog/living-on-the-edge-with-livepush-and-other-cli-improvements/
|
# Living on the edge with livepush… and other CLI improvements
Here at balena, we understand that the primary users of our platform are engineers. For a long time, the tooling we provided for developers and DevOps engineers wasn’t as user-friendly or cohesive as we’d have liked it to be. So a few months back, we decided to focus on improving the experience when using balenaCloud and balenaOS. Here’s what we did…
With all the new features and functionality, we naturally had to make some significant behavioral changes to the CLI, for this reason, we decided to designate this as a major release. We believe most of the major changes work to improve the consistency and usability of the CLI and further our goal of having the CLI as a central tool in all balena workflows. See Major Changes for an in-depth list of all the changes in balena CLI v11, or if you just want to try it now click the button below to find the latest relase on GitHub.
### Local mode
The first step in our mission to deliver a better user experience was finding a way to reduce the time between code changing and it running on your device. We already had the command balena local push, but this feature lived in isolation, it didn’t support multi-container, and was difficult to update. We decided to scrap the existing workflow and instead use the supervisor, as the container orchestration code already existed and now the supervisor was part of balenaOS in both managed and unmanaged devices. Note that local mode is only supported on .dev variants of balenaOS and on balena cloud it needs to be explicitly enabled.
To perform a local mode push, in your project directory, execute balena push <device-ip> or balena push <short-uuid>.local. This will attempt to communicate with the supervisor and docker daemon on the target device, which will detect information about your device, and resolve any Dockerfile.template files. The builds will then occur on-device. Note, this may be slower for the first push than using the cloud builder (in general), but subsequent pushes will make use of docker layer caching, and will be much faster.
Once the builds have completed, a target state is generated, in much the same way as balenaCloud. The supervisor then applies this target state, and your code will be running!
Two things then happen;
1. The logs of the services and the supervisor will be streamed into your terminal. This can be controlled with the --detached flag. You can also specify which services you want to get logs from (--service) and whether to receive system (supervisor) logs (--system).
2. The directory in which the code resides will be watched for changes. When any change occurs, a livepush process (more on this below) will start, and your changes will be automatically applied. This can be turned off by supplying the --nolive flag.
### Livepush
Livepush is a recent innovation here at balena, created to streamline the entire workflow when developing on balena devices. At the core of livepush is the idea that it shouldn’t be necessary to change your workflow or code to use it, and we’ve tried to stick to that as much as possible.
As an example, let us consider the following fairly typical Dockerfile.template for a typescript application:
FROM balenalib/%%BALENA_ARCH%%-node:10 # step 1
WORKDIR /usr/src/app #step 2
COPY package.json . #step 3
RUN npm install # step 4
COPY src/*.ts src/ # step 5
RUN npm run build # step 6
CMD node build/app.js # step 7
The livepush process will look at the Dockerfile, and split it into groups internally. These groups have dependencies on external files, just like in Docker layer caching. If, for example, we changed the package.json file, step 3 onwards would become invalidated, but a source file change would only invalidate step 5 onwards.
The difference between docker layer caching and livepush is that once a layer is invalidated in docker, the entire layer needs to be regenerated, but this is not the case with livepush. To improve on docker layer caching, instead of creating a new image and container with every code change, we execute the dockerfile commands from within the running container. This means that, for example, if you added a dependency to your package.json, rather than having to install all of the dependencies again, only the new dependency would be. If your language stack supports incremental compilation, a source file change would cause only a single file to be recompiled.
Let’s use the above Dockerfile in an example. I add a dependency to the package.json file and hit save. Livepush detects this change and looks at the group information it’s holding internally. It discovers that step 3 references the changed file and copies the package.json into the container, overwriting the existing one. Now all other steps must be run (technically), so we re-run the npm install. Of course, all of the other dependencies are there, so only the new one will be installed (so we’re already quicker than docker would be).
Livepush then moves to step 5, discovers that the file changed is not referenced in this step, and skips it. Step 6 now has to be run, but due to typescript’s new incremental compilation no compilation would occur and we would quickly finish the process. At this point, the container will be restarted, so the CMD line can be re-executed, and the new code is running.
If we instead changed a source file, livepush would copy in the file at step 5, re-run the build (remember only a single file will be compiled) and the container would then be restarted.
The following shows a livepush process when I make a change to the frontend service:
### Logs
I mentioned earlier that balena push now streams back device logs. It’s also possible to do this using the balena logs command, which accepts the same flags (--service, --system). This now works with multi-container and more importantly, the same command (balena logs) will work on a local device (if a <short-uuid>.local or <device-ip> is provided) or a cloud device (if a uuid is provided). It’s that easy!
### SSH
The ssh commands have also been refreshed. Firstly balena local ssh has been removed, and balena ssh options have been revamped. The command now takes an application name, a device uuid or a local device address. Optionally it can also take a service name. If there is no service name, a shell on the host OS will be started, if there is a service name, a shell inside the service container will be started. If an application name is passed to balena ssh you will be presented with a dialogue to select the online device to connect to. Also, no more sudo!
### Native Installers
Last but not least, we have a BETA release for our CLI native installers. Currently, there are installers for macOS and Windows, with Linux in the works. The installers offer a familiar click-through install experience for the CLI which improves and simplifies the installation process. No more npm install or messing with your OS path. You can find the installers on the CLI github releases page starting from v11.0.0 . In the coming weeks we will be improving these installers by adding easy update functionality and digitally signing them so MacOS and Windows don’t complain of “Unknown Developer”. We are excited by how much this simplifies the use of the CLI, and we can’t wait for your feedback on the new install experience.
### Major Changes
To improve the consistency of the CLI, all the local namespace commands were removed or merged into top-level commands, with the exception of local flash and local configure.
• balena local push has been replaced by balena push <deviceIP | short_UUID.local>
• balena local ssh has been replaced by balena ssh <deviceIP | short_UUID.local>
• balena local stop has been removed
• balena local scan has been moved to balena scan
The behavior of balena ssh has subtly changed. It now requires that you specify the name of the service you wish to SSH into. If no service name is supplied, you will be dropped into a shell session on the balena HostOS.
balena push now defaults to using the livepush functionality. If you wish to maintain the old behavior you will need to supply the --nolive flag.
balena sync has been removed in favor of balena push as the livepush syncing offers a better and more consistent development workflow. In future versions we will also enable remote livepush to .dev devices.
Last of all, we have removed the balena signup command, all signups for balenaCloud will now be directed through dashboard.balena-cloud.com.
### Get in Touch
There are many more exciting updates in the pipeline but in the meantime, we hope you enjoy the improved user experience we’re aiming to deliver. We would love to know what you think of these latest developments and answer any questions you may have. As always, you can find us in the forums!
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|
https://www.learnlatex.org/en/lesson-11
|
# Formatting: fonts and spacing
## Paragraph spacing
We have already seen that a blank line in your input will generate a new paragraph in LaTeX. This shows up as the paragraph will start with an indent. One common style is to have no indents for paragraphs, but instead to have a ‘blank line’ between them. We can achieve that using the parskip package.
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[parfill]{parskip}
\usepackage{lipsum} % Just for some filler text
\begin{document}
\lipsum
\end{document}
## Forcing a new line
Most of the time, you should not force a new line in LaTeX: you almost certainly want a new paragraph or to use parskip, as we’ve just seen, to put a ‘blank line’ between paragraphs.
There are a few places where you use \\ to start a new line without starting a new paragraph
• At the end of table rows
• Inside the center environment
• In poetry (the verse environment)
Almost always, if you are not in one of those special places, you should not use \\.
We can insert a thin space (about half the normal thickness) using \,. In math mode, there are also other commands: \., \: and \;, and one for a negative space: \!.
Very rarely, for example when creating a title page, you might need to add explicit horizontal or vertical space. We can use \hspace and \vspace for that.
\documentclass{article}
\usepackage[T1]{fontenc}
\begin{document}
Some text \hspace{1cm} more text.
\vspace{10cm}
Even more text.
\end{document}
## Explicit text formatting
We saw a while ago that most of the time logical structure is preferable. But sometimes you want to make text bold, or italic, or monospaced, etc. There are two types of command for this: ones for short pieces of text, and ones for ‘running’ material.
For short bits of text, we use \textbf, \textit, \textrm, \textsf, \texttt and \textsc.
\documentclass{article}
\usepackage[T1]{fontenc}
\begin{document}
Let's have some font fun: \textbf{bold}, \textit{italic}, \textrm{roman},
\textsf{sans serif}, \texttt{monospaced} and \textsc{small caps}.
\end{document}
For running text, we use commands that alter the font setup; the commands here are for example \bfseries and \itshape. Because these don’t ‘stop’, we need to place them in a group if we want to prevent them from applying to the whole document. LaTeX environments are groups, as are table cells, or we can use {...} to make an explicit group.
\documentclass{article}
\usepackage[T1]{fontenc}
\begin{document}
Normal text.
{\itshape
This text is italic.
So it this: the effect is not limited to a paragraph.
}
\end{document}
We can set font size in a similar way; these commands all work on an ongoing basis. The sizes we set are relative: \huge, \large, \normalsize, \small and \footnotesize are common. It’s important to finish a paragraph before changing the font size back; see how we add an explicit \par (paragraph break) here.
\documentclass{article}
\usepackage[T1]{fontenc}
\begin{document}
Normal text.
\begin{center}
{\itshape\large Some text\par}
Normal text
{\bfseries\small Much smaller text\par}
\end{center}
\end{document}
## Exercises
Experiment with manual formatting: create a titlepage environment and try inserting different spaces and font changes. What happens when we combine font changes? How does this compare to math mode?
What happens if you change the font size of a large paragraph (try with \tiny then with \huge) but don’t issue a final \par before closing the group?
See more on this topic
Next lesson
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https://dspace.nwu.ac.za/handle/10394/1872/browse?value=Generalized+Zakharov%E2%80%93Kuznetsov+equation&type=subject
|
Now showing items 1-1 of 1
• #### Conservation Laws and Exact Solutions of a Generalized Zakharov Kuznetsov Equation
(Mdpi Ag, 2015)
In this paper, we study a generalized Zakharov–Kuznetsov equation in three variables, which has applications in the nonlinear development of ion-acoustic waves in a magnetized plasma. Conservation laws for this equation ...
Theme by
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https://stats.stackexchange.com/questions/404522/the-use-of-cross-validation-in-dynamic-linear-model-or-state-space-model
|
# The use of cross validation in Dynamic Linear Model (or state space model)
The dynamic linear model has the form as
$$y_t = m(\theta_t, x_t) + \epsilon_t ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ (1)\\ \theta_{t+1} = F \theta_t + R \eta_t,~\eta_t \sim N(\mu_t,\Sigma_t) ~~~~~~(2)$$ where $$m(\theta_t, x_t)$$ is a mapping function, Equation (1) is known as the observation equation and Equation (2) is known as the hidden state equation.
The question is that if I want to compare the prediction performance between the dynamic linear model and another model, say, linear regression model, is it reasonable to use the cross-validation techniques? Or are there other reasonable techniques?
Out-of-sample method, which uses a block of data at the end of the observed series points, is an option, but I am looking for cross-validation like method.
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http://mathhelpforum.com/calculus/54878-using-midpoint-rule-appromiate-area-bounded-curvves.html
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# Thread: Using Midpoint rule to appromiate area bounded by curvves
1. ## Using Midpoint rule to appromiate area bounded by curvves
I thought I had the process but I was off apparently. The equations are y=sin^2(pi x/4), y=cos^2(pi x/4) 0, greater or equal to x, greater or equal to 1)
2. Originally Posted by sfgiants13
I thought I had the process but I was off apparently. The equations are y=sin^2(pi x/4), y=cos^2(pi x/4) 0, greater or equal to x, greater or equal to 1)
The directions of the inequalities are wrong, but assume you mean for $0 \le x \le 1$. Then area is:
$A=\int_{x=0}^1 \cos^2(\pi x/4)-\sin^2(\pi x/4)\ dx$
now what is the difficulty?
CB
3. Originally Posted by CaptainBlack
The directions of the inequalities are wrong, but assume you mean for $0 \le x \le 1$. Then area is:
$A=\int_{x=0}^1 \cos^2(\pi x/4)-\sin^2(\pi x/4)\ dx$
now what is the difficulty?
CB
Yeah sorry...it was use the midpoint rule and n=4 to approximate the area between the curves.
4. Originally Posted by sfgiants13
Yeah sorry...it was use the midpoint rule and n=4 to approximate the area between the curves.
You want four subintervals of the interval interval $[0,1]$, so they are each of length $0.25$, and have mid points $0.125, 0.375, 0.625, 0.875$, or:
$x_i=\frac{b-a}{n} \times (k+0.5), \ \ k=0,1,.., n-1$
are the interval mid points, where $a, b$ are the limits of integration, and $n$ is the number of subintervals.
Then:
$\int_a^b f(x)\ dx \approx \frac{b-a}{n}\sum_{k=0}^{n-1}f(x_i)$
or writing $h=(b-a)/n$
$x_i=h \times (k+0.5), \ \ k=0,1,.., n-1$
$\int_a^b f(x)\ dx \approx h\sum_{k=0}^{n-1}f(x_i)$
which is the sum of the function at the mid points of the intervals times the interval length
CB
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http://math.stackexchange.com/questions/247318/show-that-expected-value-exist?answertab=active
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# Show that expected value exist
If I know that $E[X^2]$ exist, how can I show that $E[X]$ exist? For me it's obvious, but I don't have idea how to show it, because I don't have any information about distribution. Maybe someone can give a hint?
-
Hint: $1 + X^2 > |X|$ for all $X$. – Dilip Sarwate Nov 29 '12 at 15:38
Great, thank you! – Johnny Nov 29 '12 at 20:23
I assume, $X$ is measurable, then the nonexistence of $E[X]$ would mean that either the positive or the negative part of the integral wants to go to infinity. But then $X^2$ would go even faster as the base is of finite measure.
Let $A:=\{\omega|X(\omega)\ge 0\}=:(X\ge 0)$ and $B:=(X<0)$, then, using that $x\le x^2$ if $x\ge 1$, we have $$\int_A X \le \int_{X\ge 1} X^2+\int_{0\le X<1}1\le E[X^2]+1$$ And similarly over $B$.
Yes, exist means that $E[X] < inf$ – Johnny Nov 29 '12 at 19:59
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https://en.uncyclopedia.co/wiki/Progressive_rock
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# Prog Rock
(Redirected from Progressive rock)
Whoops! Maybe you were looking for Elitism?
A late addition to the Prog Rock scene, Germany's Wilhelm Scream featured traditional airbrushed artwork on their gatefold double album covers, as well as a 38 minute opus to the Battle of Thermopylae.
The Pink Floyds 1978 Album was panned by PETA.
“I much prefer Brighton Rock, or Blackpool if I can't get any of that”
~ Noel Coward on Prog Rock
“The time between the notes relates the colour to the scene.”
Jon Anderson on umm...
Progressive rock (not to be confused with Prod rock) was a particularly widespread, genre of music, which is thought to be mostly under control now in the civilised world. Groups such as Pink Floyd, Deaf To Van Gogh's Ear, ELP, Genesis, King Crimson, Rush, Yes and the much later Marillion were rife amongst the, pseudointellectual (mainly male) youth, much as the Grunge genre of the early 90's became to deadly effect. Most Progressive Rock bands only lasted a limited time, band members often breaking up due to musical similarities (or in Pink Floyd's case, Roger Waters), except Marillion who defined the Popular Prog Rock genre.
Sometimes referred to as "Prague Rock" due to its roots in Czechloslovakian Folk Music, progressive rock rebelled against the more popular regressive rock, in which artists would work backwards, from material about self actualization, metaphysical ethics and gnoseology, to songs like "Work Sucks", "School Sucks", "I Want My Mommy" and finally "Gurgle Gurgle". In short, progressive rock groups decided to stop writing three-minute songs about sex and instead wrote ten-minute songs about God knows what (although it is believed that Jon Anderson knows the meanings of the lyrics of all prog songs ever written).
And remember: if we'd had CDs in 1971, "Echoes" would have been eighty-seven goddamn minutes long.
## Origins of Prog Rock
Prog rock was first founded when some racist Europeans decided they had it with that rock music based on "nigger blues" and decided to create rock music based on Aryan classical music. Just like Hitler they were hugely popular at their heyday, but as soon as they tried too hard they were thrown in the trashcan, only to be talked about with shame. Today they mostly hang around dark websites reminsicing about Robert Fripp and Brian Eno's sudden hair loss. Some folks still believe Jon Anderson will lead them back to prog days of yore but Jon (from his hospital bed) has deemed it "Quite improbable and inherently unlikely".
With their love for the flamboyant and theatrical Progressive Rock soon cut a colourful swave through the music scene, as long haired youths nodded knowingly into pints of Guinness and light ales worldwide, whilst discussing the musical virtuosity of Karn Evil 9, or the sheer genius of a 27 minute Mellotron solo, or the sheer genius of a 18 minute guitar solo, or the sheer genius of a 3 second bass solo. Every single progressive band from the heyday used a man named Bill Bruford as a drummer because he thought 4 was 7.
Prog Rock is also known to be the final evolution of Rock music, using over-the-top insane musical composition (which may or may not be influenced by LSD hallucinations) and impossible-to-understand lyrics about moonchildren, tales from topographic oceans or "man-ergs" (confirmed to have been influenced by LSD hallucinations). The lower species called Punk decided to rise against it. Punk defended that each band was supposed to write only one 3 chord song during their carrier, and only change this song's lyrics along the albums. This clashed into a Prog vs. Punk war that lasts to this day, with neither side showing signs of wanting to give up.
## Characteristics
• 27 minute song composition (or longer).
• Analogue synthesizers and mellotrons.
• Keyboard solos especially where they do not belong (you heard me Emerson)
• Playing bass guitar
• ...subsiquently taking over the band andtaking credit for everything the band has written
• Mandolins (see Mike Oldfield).
• "Creative" hair stylings (see here).
• Dressing up in robes, a cape, and a wizard hat.
• Going down to Willow Farm to look for butterflies, flutterbies and gutterflies.
• Singing about hard-hitting themes such as moonlit knights and eclipses, or the warrior of today's Tom Sawyer.
• Possessing an extended vocabulary of big, fancy words.
• Building walls during concerts...big, expensive walls.
• Time signatures unknown to mankind (for example only the shreddergod John Petrucci of Dream Theater knows how to play 69/420).
• Selling out and turning pop in '80s.
A typical notation of a Gentle Giant song.
## The Progressive Rock Article Suite I-III
### Part I: The Definition
Progressive Rock
What It Is?
It Can't Really Be Defined
Which Leads to Long Battles Boring As Hell Battles Between Morons
"What Is Prog
And What Is Not"
The Truth Lies
Beyond
The Faraway Galaxies
There's Something On The Loose
Yesterday I Found A Moose... Or Should It Be Goose?
Or Geese Or Meese, Caboose Or Cabeese,
The Mice In The Hice, And The Grouse In The House
Which Jumped Over a Fence
Yes, This Doesn't Make any Fuckin' Sense. Anyways, 'Does Anyone Have Any Good Pot Around Here?'
Concentration, Will Be My Epitaph,
As I drawl on a cracked and open snatch,
If we make it, we can all sit back,
And smoke crack
Shine On You Sane Crystal
In other words Progressive Rock is like Drugs, Drugs & Roll, Rock & Roll, Rocks, Drugs and Spam! (see Jethro Tull for more)
### Part II: We Are the Children of Eternal Light / The Author Still Doesn't Have Any Imagination to Come Up With Something Funny, Including 'The Cleaning of the Underwear Drawer', and 'Cthulhu's Lament (in \$ flat Sergeant-Major, with change)' (The Development section) in 11/8, 9/8, 5/4, π/7, 9/16, 16mm and acid
Well, At Least the Keyboardist Must Wear a Cape.
Bass solo (about two seconds/five notes/not at all)
Drum solo (two minutes, nineteen seconds, by law)
Other guitar solo (about fifteen more minutes)
Random jamming with incoherent lyrics about quantum panties, and audible snoring of the Sound Engineer in the background (about twenty minutes) [[1]]
### Part III: The Definition (Reprise in Five)
Progr essiv eRock WhatI tIs?I
tCan' tReal lyBeD efine dWhic
AsHel lBatt lesBe tween Nerds
"What IsPro gAndW hatIs Not"
#### Coda: T-T-T-T-T-That's All Folks! (featuring vocalist: Porky Pig)
Expressionistic soundscapes (or: the Sound Engineer yawns, farts, scratches his stomach, walks into the playing room, missteps on the dwarfed flautist of the band because of thick smoke covering the room and falls on the drum set cursing like a seaman)
"Well At Least It's Fucking Boring And Corny!" - Mr. Obvious (1974)
(unfortunately (or not, depending on your preference,) the recorder ran out of tape 17 minutes before the band stopped playing)
## Tabulature
Band: Uncyclopediarium
Song: The Progressive Rock Article Suite Intro
. - palm mute / - slide up to
\ - slide down to ~ - vibrato
h - hammer on b - Bend
p - pull off Suffixes for bend
t - tap f - full bend h - half bend
ph - pinched harmonic q - quarter bend t - tap bend
* - see comment ^ - Hold bend r - release bend
x - Succatto ~ - vibrato bend e - bend with string breaking
S - Stutter g - get bent
, - slight palm mute () - ghost note, sustained note
(X_X) Ghostface Killah note
" - tremolo note <> - Trill
% - pose & - pluck with an eyebrow
U - unintentional action Y - really unintentional action
@ - bang the guitar against the monitor
a - have an acid flashback
q - do something really fucking stupid
! - run in circles, waving the guitar in the air
while uncontrollably picking the strings
u - untie vocalist's hair from strings
T - try to tune the string, unsuccessfully
s - soil yourself on cue and call it avant-garde
F - set fire to drummer
tb - tab the song while performing it
WARNING: Do not try playing the guitar by banging the strings with your nuts!
(silence actually because the guitarist is missing)
e ||-------------------|-------------------|-------------------|-------------------|
B#||-------------------|-------------------|-------------------|-------------------|
Hb||-------------------|-------------------|-------------------|-------------------|
Db||-------------------|-------------------|-------------------|-------------------|
A#||-------------------|-------------------|-------------------|-------------------|
Bb||-------------------|-------------------|-------------------|-------------------|
sound eng: snoring
e ||-------------------|-------------------|-------------------|-------------------|
B#||-------------------|-------------------|-------------------|-------------------|
Hb||-------------------|-------------------|-------------------|-------------------|
Db||-------------------|-------------------|-------------------|-------------------|
A#||-------------------|-------------------|-------------------|-------------------|
Bb||-------------------|-------------------|-------------------|-------------------|
e ||-------------------|---------U0--------|-0-----------0-----|-0------------0----|
B#||-------------------|-------------------|---6-----6----6----|---6bf^^^^^r-------|
Hb||-------------------|-------------------|-----0-----0----0--|-----565-65--------|
Db||-------------------|-------------------|-------7----------7|--------4----------|
A#||-------------------|-------------------|-8-----------8-----|-8-----------Y9----|
Bb||-------------------|-------------------|------------U0-----|-------------------|
drums: dumdurum dumdum vocal: D A Ab Wb Щ#
e ||-6\0/7-------------|-5\4---------------|-0-----------%-----|----2--3\2---3-5---|
B#||-------3\0/4\pi----|---4/5-------------|-2U,-3h22Y,--%-----|-----3--4\3-2------|
Hb||-------------------|-----3\i-----------|-0U,----3Y,--%-----|------2----3--4----|
Db||-------------------|--------&5\&4------|-2U.---------%-----|--0-------4---5---T|
A#||-------------------|-------------&3h2--|-0U.---------%-----|---1---------------|
Bb||-------------------|-------------------|-0U,---------%-----|-------------------|
sixth string: Zb J# µb @!^#* ouch, it hurts [goes to her mom]
e ||-1\2---4--4--------|-3---5-3-3\2-------|-16h14---10\2------|-24h23-----23h20---|
B#||---2--3-2----------|--4-4-34----3\4----|----15h10---3h4----|-----16h12---------|
Hb||---3\2--3----------|---2--4-------24h23|--------------14h5-|---------7h5--8h6--|
Cb||------4----2-------|----4-5------------|-------------------|-------------------|
A#||---------5--2------|-------------------|-------------------|-------------------|
Bb||-----------2-2be | | | |
drums: undistinguishable from line noise audience: [wakes up]
e ||-24-----------!--!-|-!20--------@6--@-@|@Googol@--@--0-----|--Y8--7h3----------|
B#||--23h20---23---!-!-|---!---------@3-@--|-@ | |
Hb||--22---22h20----!--|---!-!!!u----@4@-@4|--@8--@-@ | F|
Cb||---------------!---|-!--!---u---@-2@@2-|--@5-@-@-@---0-----|--Y9h5---7b~e |
A#||---------------!-!-|-!--!---u-----@69--|----@20@-----------|-------------------|
Bb|| | | | |
## Bankruptcy
One common side effect of Progressive Rock is bankruptcy. This can be caused by the following:
Most of this can be alleviated by contracting different viruses such as Punk or Indie.
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https://math.stackexchange.com/questions/567218/derivatives-of-component-maps
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# Derivatives of component maps
Given functions $f_1:\mathbb{R}^{a_1}\rightarrow\mathbb{R}^{b_1}$ and $f_2:\mathbb{R}^{a_2}\rightarrow\mathbb{R}^{b_2}$, and the function $f:\mathbb{R}^{a_1+a_2}\rightarrow\mathbb{R}^{b_1+b_2}$ is defined by $$f(x,y)=(f_1(x),f_2(y))$$ for $x\in\mathbb{R}^{a_1},y\in\mathbb{R}^{a_2}$.
Take points $z=(z_1,z_2)$ and $w=(w_1,w_2)$, where $z_1,w_1\in\mathbb{R}^{a_1},z_2,w_2\in\mathbb{R}^{a_2}$.
Is it true that $Df(z)w=(Df_1(z_1)w_1, Df_2(z_2)w_2)$?
## 1 Answer
We have \begin{align*}\def\norm#1{\left\lVert#1\right\rVert} f(z+w) &= \bigl(f_1(z_1+w_1), f_2(z_2 + w_2)\bigr)\\ &= \bigl(f_1(z_1) + Df_1(z_1)w_1 + o(\norm{w_1}), f_2(z_2) + Df_2(z_2)w_2 + o(\norm{w_2}) \bigr)\\ &= f(z) + \bigl(Df_1(z_1)w_1, Df_2(z_2)w_2\bigr) + o(\norm{w}) \end{align*} As $w \mapsto \bigl(Df_1(z_1)w_1, Df_2(z_2)w_2\bigr)$ is linear in $w$, we have $Df(z)w = \bigl(Df_1(z_1)w_1, Df_2(z_2)w_2\bigr)$ by defnition.
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http://openstudy.com/updates/4fe23473e4b06e92b8712806
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## tux 4 years ago Given a group of 10 men and 5 women: a) how many ways can you choose a committee with 4 members b) How many combinations of 4 have 2 men on them c) have less men than women d) if Mary and John won't serve together how many 4 members combinations are possible? Delete Cancel Submit
• This Question is Closed
1. anonymous
• 4 years ago
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a) $C _{4}^{15}=1365$
2. anonymous
• 4 years ago
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b) $C_{2}^{10}\times C _{2}^{5}=450$
3. anonymous
• 4 years ago
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c) $C _{1}^{10}\times C _{3}^{5}=100$
4. anonymous
• 4 years ago
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d)$2\times C _{4}^{14}- C _{4}^{13}=1287$
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https://www.gradesaver.com/textbooks/science/physics/college-physics-4th-edition/chapter-8-problems-page-315/58
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## College Physics (4th Edition)
(a) The angular acceleration of the merry-go-round is $~0.111~rad/s^2$ (b) After 4.0 seconds, the angular speed is $~0.444~rad/s$
(a) We can find the angular acceleration of the merry-go-round: $\tau = I~\alpha$ $2~(R\times F) = I~\alpha$ $\alpha = \frac{2~(R\times F)}{I}$ $\alpha = \frac{2~(R\times F)}{\frac{1}{2}MR^2}$ $\alpha = \frac{4~F}{MR}$ $\alpha = \frac{(4)(10.0~N)}{(180~kg)(2.0~m)}$ $\alpha = 0.111~rad/s^2$ The angular acceleration of the merry-go-round is $~0.111~rad/s^2$ (b) We can find the angular speed after 4.0 seconds: $\omega_f = \omega_0+\alpha~t$ $\omega_f = 0+(0.111~rad/s^2)(4.0~s)$ $\omega_f = 0.444~rad/s$ After 4.0 seconds, the angular speed is $~0.444~rad/s$.
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http://link.springer.com/article/10.1007%2Fs10468-010-9230-x
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Article
Algebras and Representation Theory
, Volume 15, Issue 1, pp 1-27
First online:
# Universal Enveloping Algebras of Lie Antialgebras
• Séverine LeidwangerAffiliated withInstitut Mathématiques de Jussieu, Théorie des groupes, Université Denis Diderot Paris 7
• , Sophie Morier-GenoudAffiliated withInstitut Mathématiques de Jussieu, Université Pierre et Marie Curie Paris 6 Email author
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## Abstract
Lie antialgebras is a class of supercommutative algebras recently appeared in symplectic geometry. We define the notion of enveloping algebra of a Lie antialgebra and study its properties. We show that every Lie antialgebra is canonically related to a Lie superalgebra and prove that its enveloping algebra is a quotient of the enveloping algebra of the corresponding Lie superalgebra.
### Keywords
Jordan superalgebra Lie superalgebra Universal enveloping algebra
### Mathematics Subject Classifications (2010)
17C50 17C70 17B60
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http://www.aimsciences.org/article/doi/10.3934/dcds.2004.10.435
|
American Institute of Mathematical Sciences
January & February 2004, 10(1&2): 435-458. doi: 10.3934/dcds.2004.10.435
On a limiting system in the Lotka--Volterra competition with cross-diffusion
1 Department of Mathematics, The Ohio State State University, Columbus, Ohio 43210, United States 2 School of Mathematics, University of Minnesota, Minneapolis, Minnesota 55455, United States 3 Department of Applied Mathematics and Informatics, Ryukoku University, Seta, Otsu, 520-2194
Received January 2002 Revised March 2003 Published October 2003
In this paper we investigate a limiting system that arises from the study of steady-states of the Lotka-Volterra competition model with cross-diffusion. The main purpose here is to understand all possible solutions to this limiting system, which consists of a nonlinear elliptic equation and an integral constraint. As far as existence and non-existence in one dimensional domain are concerned, our knowledge of the limiting system is nearly complete. We also consider the qualitative behavior of solutions to this limiting system as the remaining diffusion rate varies. Our basic approach is to convert the problem of solving the limiting system to a problem of solving its "representation" in a different parameter space. This is first done without the integral constraint, and then we use the integral constraint to find the "solution curve" in the new parameter space as the diffusion rate varies. This turns out to be a powerful method as it gives fairly precise information about the solutions.
Citation: Yuan Lou, Wei-Ming Ni, Shoji Yotsutani. On a limiting system in the Lotka--Volterra competition with cross-diffusion. Discrete & Continuous Dynamical Systems - A, 2004, 10 (1&2) : 435-458. doi: 10.3934/dcds.2004.10.435
[1] Yuan Lou, Wei-Ming Ni, Yaping Wu. On the global existence of a cross-diffusion system. Discrete & Continuous Dynamical Systems - A, 1998, 4 (2) : 193-203. doi: 10.3934/dcds.1998.4.193 [2] Daniel Ryan, Robert Stephen Cantrell. Avoidance behavior in intraguild predation communities: A cross-diffusion model. Discrete & Continuous Dynamical Systems - A, 2015, 35 (4) : 1641-1663. doi: 10.3934/dcds.2015.35.1641 [3] Yi Li, Chunshan Zhao. Global existence of solutions to a cross-diffusion system in higher dimensional domains. Discrete & Continuous Dynamical Systems - A, 2005, 12 (2) : 185-192. doi: 10.3934/dcds.2005.12.185 [4] Esther S. Daus, Josipa-Pina Milišić, Nicola Zamponi. Global existence for a two-phase flow model with cross-diffusion. Discrete & Continuous Dynamical Systems - B, 2017, 22 (11) : 0-0. doi: 10.3934/dcdsb.2019198 [5] Yanxia Wu, Yaping Wu. Existence of traveling waves with transition layers for some degenerate cross-diffusion systems. Communications on Pure & Applied Analysis, 2012, 11 (3) : 911-934. doi: 10.3934/cpaa.2012.11.911 [6] Y. S. Choi, Roger Lui, Yoshio Yamada. Existence of global solutions for the Shigesada-Kawasaki-Teramoto model with strongly coupled cross-diffusion. Discrete & Continuous Dynamical Systems - A, 2004, 10 (3) : 719-730. doi: 10.3934/dcds.2004.10.719 [7] Y. S. Choi, Roger Lui, Yoshio Yamada. Existence of global solutions for the Shigesada-Kawasaki-Teramoto model with weak cross-diffusion. Discrete & Continuous Dynamical Systems - A, 2003, 9 (5) : 1193-1200. doi: 10.3934/dcds.2003.9.1193 [8] Yaping Wu, Qian Xu. The existence and structure of large spiky steady states for S-K-T competition systems with cross-diffusion. Discrete & Continuous Dynamical Systems - A, 2011, 29 (1) : 367-385. doi: 10.3934/dcds.2011.29.367 [9] Robert Stephen Cantrell, Xinru Cao, King-Yeung Lam, Tian Xiang. A PDE model of intraguild predation with cross-diffusion. Discrete & Continuous Dynamical Systems - B, 2017, 22 (10) : 3653-3661. doi: 10.3934/dcdsb.2017145 [10] Yuan Lou, Wei-Ming Ni, Shoji Yotsutani. Pattern formation in a cross-diffusion system. Discrete & Continuous Dynamical Systems - A, 2015, 35 (4) : 1589-1607. doi: 10.3934/dcds.2015.35.1589 [11] Hideki Murakawa. A relation between cross-diffusion and reaction-diffusion. Discrete & Continuous Dynamical Systems - S, 2012, 5 (1) : 147-158. doi: 10.3934/dcdss.2012.5.147 [12] Kousuke Kuto, Yoshio Yamada. Coexistence states for a prey-predator model with cross-diffusion. Conference Publications, 2005, 2005 (Special) : 536-545. doi: 10.3934/proc.2005.2005.536 [13] Kousuke Kuto, Yoshio Yamada. On limit systems for some population models with cross-diffusion. Discrete & Continuous Dynamical Systems - B, 2012, 17 (8) : 2745-2769. doi: 10.3934/dcdsb.2012.17.2745 [14] F. Berezovskaya, Erika Camacho, Stephen Wirkus, Georgy Karev. "Traveling wave'' solutions of Fitzhugh model with cross-diffusion. Mathematical Biosciences & Engineering, 2008, 5 (2) : 239-260. doi: 10.3934/mbe.2008.5.239 [15] Anotida Madzvamuse, Hussaini Ndakwo, Raquel Barreira. Stability analysis of reaction-diffusion models on evolving domains: The effects of cross-diffusion. Discrete & Continuous Dynamical Systems - A, 2016, 36 (4) : 2133-2170. doi: 10.3934/dcds.2016.36.2133 [16] Anotida Madzvamuse, Raquel Barreira. Domain-growth-induced patterning for reaction-diffusion systems with linear cross-diffusion. Discrete & Continuous Dynamical Systems - B, 2018, 23 (7) : 2775-2801. doi: 10.3934/dcdsb.2018163 [17] Shanbing Li, Jianhua Wu. Effect of cross-diffusion in the diffusion prey-predator model with a protection zone. Discrete & Continuous Dynamical Systems - A, 2017, 37 (3) : 1539-1558. doi: 10.3934/dcds.2017063 [18] Lianzhang Bao, Wenjie Gao. Finite traveling wave solutions in a degenerate cross-diffusion model for bacterial colony with volume filling. Discrete & Continuous Dynamical Systems - B, 2017, 22 (7) : 2813-2829. doi: 10.3934/dcdsb.2017152 [19] Salomé Martínez, Wei-Ming Ni. Periodic solutions for a 3x 3 competitive system with cross-diffusion. Discrete & Continuous Dynamical Systems - A, 2006, 15 (3) : 725-746. doi: 10.3934/dcds.2006.15.725 [20] Yuan Lou, Salomé Martínez, Wei-Ming Ni. On $3\times 3$ Lotka-Volterra competition systems with cross-diffusion. Discrete & Continuous Dynamical Systems - A, 2000, 6 (1) : 175-190. doi: 10.3934/dcds.2000.6.175
2018 Impact Factor: 1.143
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|
https://psspy.org/psse-help-forum/question/6230/how-to-create-a-p-q-curve-of-the-solar-farm/
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# How to create a P-Q curve of the solar farm
Hi there
Right now, I am trying using PSSE GUI to create a P-Q curve for the solar farm. I already build the SMIB which is connect to transformer and the generator. However, what is the next step to get the data for create the P-Q curve(to confirm the Reactive Power Capability of the solar inverter) of the generator?
Does anyone know what is the reason?
Thanks very much for your valuable time and kind help in advance!!
edit retag close merge delete
I don't understand what you want to do. Is it for load flow calculation or a dynamic simulation?
( 2019-08-26 03:31:44 -0500 )edit
I am not sure it is for load flow or a dynamic simulation. However, I think it may be load flow calculation. I just want to get the P-Q curve to confirm the reactive power capability of the solar inverter. Thank you very much.
( 2019-08-26 04:06:01 -0500 )edit
Sort by » oldest newest most voted
To get the P-Q capability curve of a solar plant at its POI - In the load flow case, choose an operating mode for the solar plant (k-power factor, v-control...) and choose a voltage setting (typical value of operation or 1.0). Also choose a MW increment (maybe 10% of Pmax). It is important to have a line separating the POI bus of the solar plant from the SMIB generator. Then:
1- dispatch the solar plant at Pmin (say 10% of Pmax)
2- solve the load flow and record the P and Q output leaving the POI bus, point (Ppoi, Qpoi)
3- add the MW increment to the dispatch value of the solar plant (say now at 20%)
4- go to step 2 and repeat until the solar plant reaches its Pmax value
I would recommend to perform such study in a realistic network at the POI where the solar plant is located.
more
Thank you very much. It is very useful. However, I still have a little issue. This method can only get + active power & + reactive power (half of the P-Q curve). How can I get - reactive power with + active power? Thank you very much.
( 2019-08-28 04:44:37 -0500 )edit
For the region "- reactive power with + active power", you drive the generator under test in its leading power factor by lowering its voltage settings (to 0.98 or less) until -Q is produced by the load flow.
( 2019-08-28 10:04:39 -0500 )edit
The P-Q capability curve for a solar inverter is typically provided by the solar inverter manufacturer. In some studies it is important to establish the P-Q capability of a solar farm (as measured at its point of connection), which has multiple inverters, transformers and cables etc. To get the solar farm P-Q curve, you must do successive power flow calculations, respecting the P-Q limits of the individual inverters in each calculation.
more
Yes, what I really need is to create the P-Q curve of the solar farm. I already build a SMIB system with the generator(solar inverter) and also finish the power flow calculation. However, I still don't know how to get the P-Q curve of the solar farm... Thank you very much.
( 2019-08-27 04:04:09 -0500 )edit
I advise you to set up a Python script that will increase P in steps, and calculate Qmax and Qmin at each step value of P. You can write the results to a text file, CSV or Excel file, and do the plotting from there.
( 2019-08-28 08:21:49 -0500 )edit
Hi jfconroy, thank you very much. However, as I am a freshman for Python. Could you please help me how to set up? Thanks in advance.
( 2019-08-28 09:17:50 -0500 )edit
Learn Python. It is specifically designed to be easy to learn. Learning to write the code yourself is much more beneficial to you than getting code "off the shelf" from someone else. Besides, the point of this forum is not for some members to provide "off the shelf" Python scripts to other users.
( 2019-08-29 03:01:10 -0500 )edit
Please start posting anonymously - your entry will be published after you log in or create a new account.
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https://codegolf.stackexchange.com/questions/12042/xkcd-challenge-percentage-of-the-screen-that-is-x-color
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# xkcd challenge: “Percentage of the screen that is [x] color”
So I think we've all probably seen this xkcd comic:
:
This might either be too general or too difficult, I'm not sure. But the challenge is to create a program in any language that creates a window that has at least 2 colors and displays in English words what percentage of the screen is each color.
ex. The simplest solution would be a white background with black letters that read "Percentage of this image that is black: [x]%. Percentage of this image that is white: [y]%"
You can go as crazy or as simple as you want; plain text is a valid solution but if you make interesting images like in the xkcd comic that's even better! The winner will be the most fun and creative solution that gets the most votes. So go forth and make something fun and worthy of xkcd! :)
So, what do you think? Sound like a fun challenge? :)
• A "this program has 64 A's, 4 B's, ... and 34 double quotes in the source code" program would be more interesting :-) – John Dvorak Jul 11 '13 at 17:46
• OK... what are the objective winning criteria? How do you determine if any specific output is valid? Is it sufficient that it is true and it describes a property of itself numerically? – John Dvorak Jul 11 '13 at 17:48
• @JanDvorak Oh, that's a good one! The alphabet program is actually what made me think of this originally, but I didn't consider adding the source code element to it! You should post that as a question :) Yes, it is sufficient that it is true and describes itself. Hmm, you're right though, I didn't think about how I would prove that the final results were correct. I'll need a way to count all the pixels of each color in a result image, I suppose. I'll go investigate that now. (Sorry my first question had problems... I tried but I'm new at this! Thank you :)) – WendiKidd Jul 11 '13 at 19:14
• if truthiness and self-reference are the sufficient criteria, here's my golfscript contestant: "/.*/" (read: [the source code] doesn't contain a newline) – John Dvorak Jul 11 '13 at 19:23
• @JanDvorak Hmm, I tried your code here and the output was the same as the code except without the quotes. Maybe I'm not explaining this right, sorry. There must be at least 2 colors generated, and in some form of an English sentence the output must generate true words that describe what percentage of the screen each of the colors occupies. Maybe this was a silly idea. I thought it would be fun but it might not work in practice :) – WendiKidd Jul 11 '13 at 19:34
## Elm
Haven't seen anyone use this loophole yet: demo
import Color exposing (hsl)
import Graphics.Element exposing (..)
import Mouse
import Text
import Window
msg a = centered <| Text.color a (Text.fromString "half the screen is this color")
type Pos = Upper | Lower
screen (w,h) (x,y) =
let (dx,dy) = (toFloat x - toFloat w / 2, toFloat h / 2 - toFloat y)
ang = hsl (atan2 dy dx) 0.7 0.5
ang' = hsl (atan2 dx dy) 0.7 0.5
box c = case c of
Upper -> container w (h // 2) middle (msg ang) |> color ang'
Lower -> container w (h // 2) middle (msg ang') |> color ang
in flow down [box Upper, box Lower]
main = Signal.map2 screen Window.dimensions Mouse.position
• Great loophole! – Timtech Mar 21 '14 at 15:05
• I love this!!! At least for now, you get the checkmark for sheer clever points. Love it! – WendiKidd Mar 22 '14 at 4:03
• The best part is, I'm still not sure which sentence is talking about which color. – Brilliand Jun 9 '14 at 19:08
• The view source is put there by share-elm.com and is not part of the compiled JS/HTML. – hoosierEE Jun 18 '14 at 14:56
• @ML That depends on the scope of the word "this". JavaScript programmers understand... – hoosierEE Mar 14 '16 at 13:59
# JavaScript with HTML
I tried to reproduce the original comic more precisely. A screenshot is taken using the html2canvas library. The numbers are calculated repeatedly, so you can resize the window or even add something to page in real time.
Try it online: http://copy.sh/xkcd-688.html
Here's a screenshot:
<html contenteditable>
<script src=http://html2canvas.hertzen.com/build/html2canvas.js></script>
<script>
setInterval(k, 750);
k();
}
function k() {
html2canvas(document.body, { onrendered: t });
}
function t(c) {
z.getContext("2d").drawImage(c, 0, 0, 300, 150);
c = c.getContext("2d").getImageData(0, 0, c.width, c.height).data;
for(i = y = 0; i < c.length;)
y += c[i++];
y /= c.length * 255;
x.textContent = (y * 100).toFixed(6) + "% of this website is white";
q = g.getContext("2d");
q.fillStyle = "#eee";
q.beginPath();
q.moveTo(75, 75);
q.arc(75,75,75,0,7,false);
q.lineTo(75,75);
q.fill();
q.fillStyle = "#000";
q.beginPath();
q.moveTo(75, 75);
q.arc(75,75,75,0,6.28319*(1-y),false);
q.lineTo(75,75);
q.fill();
}
</script>
<center>
<h2 id=x></h2>
<hr>
<table><tr>
<td>Fraction of<br>this website<br>which is white _/
<td><canvas width=150 id=g></canvas>
<td> Fraction of<br>- this website<br> which is black
</table>
<hr>
0
<canvas style="border-width: 0 0 1px 1px; border-style: solid" id=z></canvas>
<h4>Location of coloured pixels in this website</h4>
• Nice!! Love the similarities to the xkcd comic, and the fact that I can change the text. Neat! : D – WendiKidd Jul 12 '13 at 14:46
• impressive work o.O – izabera Mar 4 '14 at 21:44
• Nifty... but I think it has to stabilize to be a "solution". Haven't thought through it entirely--but as there isn't necessarily a solution for arbitrary precision when drawing from a limited set of digit glyphs, you'll have to back off precision if it can't be solved at the higher precision you're trying. I imagine that using a monospace font that you pre-compute the black/white pixels will be necessary as well. – Dr. Rebmu Jun 15 '14 at 17:48
• You are using 3 colors, so where are the percentages for grey? ;) – M L Mar 13 '16 at 5:58
# Processing, 222 characters
I've always wanted to make my own version of that comic strip! The simplest (only?) way I could think of doing this was trial and error - draw something, count, draw again...
This program settles for an accurate percentage after a few seconds. It's not very pretty, but it's interactive; you can resize the window and it will start to recalculate.
float s,S,n;
int i;
void draw(){
frame.setResizable(true);
background(255);
fill(s=i=0);
text(String.format("%.2f%% of this is white",S/++n*100),10,10);
while(i<width*height)if(pixels[i++]==-1)s++;
S+=s/height/width;
}
It only shows percentage of white pixels; Because of antialiasing of the text, non-white pixels are not necessarily black. The longer it is running the more time it will need to update itself on a resize.
Edit:
So, it's a code-challenge; I sort of golfed it anyways. Maybe I could add some sort of graphs later, but the general principle would remain the same. The interactiveness is the neat part I think.
• Very nice!! I think you get extra credit for the interactivity; I had fun resizing the window! Very cool :) And you're my first ever response! I didn't know if anyone would want to play, so thanks. You've made my day. : D +1! (I'm curious though, why does it slow down as time goes on and it gets closer to reaching the correct percentage? I'm just curious as to what's happening, I've never seen this language before. I'm seeing a lot of new stuff poking around this site!) – WendiKidd Jul 11 '13 at 22:27
• headdesk Except I accidentally forgot to click the +1. Now +1...haha. Sorry! – WendiKidd Jul 11 '13 at 22:46
• You could add another function that allows users to draw on it with the mouse, for added interactivity. – AJMansfield Jul 12 '13 at 12:53
• Holy box shadow, Batman – Bojangles Jul 13 '13 at 6:33
• If you want to golf, you can use background(-1) instead of background(255) – Cows quack Apr 23 '17 at 15:45
# Whitespace, 381
Assumes the code is displayed fullscreen before running with a white background.
Here it is gzipped and base64-encoded for convenience:
H4sIAMds4FEAA31QQQ4AIAg6wyv4/ysbrpXaLLcWQRJKQpQIyguBMjR/YOyXNIusLTDeTp0eaP3k
4wtMtl2r6tK47PFNhpKsDaX/B5+R1WD7THIBSiw5RH0BAAA=
• +1 for introducing me to a new language! I'm having difficulty compiling it though; would you mind adding a screenshot, as other answers have done? :) it would also probably help you get more votes, as I imagine there are some people voting based on pretty pictures, lol. Just asking, do as you like. Thanks for participating!! – WendiKidd Jul 13 '13 at 14:46
• @WendiKidd It's an interpreted language, I think. No need to compile :P – Andreas Mar 21 '14 at 15:09
Great challenge. Here's my solution. I tried to get as close as possible to the original comic, I even used the xkcd font.
It's a WPF application, but I used System.Drawing to do the drawing parts because I'm lazy.
Basic concept: In WPF, windows are Visuals, which means they can be rendered. I render the entire Window instance onto a bitmap, count up the black and total black or white (ignoring the grays in the font smoothing and stuff) and also count these up for each 3rd of the image (for each panel). Then I do it again on a timer. It reaches equilibrium within a second or two.
You'll need to install the font above to your system if you want to see it, otherwise it's the WPF default one.
XAML:
<Window
x:Class="WpfApplication1.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="xkcd: 688" Height="300" Width="1000" WindowStyle="ToolWindow">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="0.3*"/>
<ColumnDefinition Width="0.3*"/>
<ColumnDefinition Width="0.3*"/>
</Grid.ColumnDefinitions>
<Border BorderBrush="Black" x:Name="bFirstPanel" BorderThickness="3" Padding="10px" Margin="0 0 10px 0">
<Grid>
<Label FontSize="18" FontFamily="xkcd" VerticalAlignment="Top">Fraction of this window that is white</Label>
<Label FontSize="18" FontFamily="xkcd" VerticalAlignment="Bottom">Fraction of this window that is black</Label>
<Image x:Name="imgFirstPanel"></Image>
</Grid>
</Border>
<Border Grid.Column="1" x:Name="bSecondPanel" BorderBrush="Black" BorderThickness="3" Padding="10px" Margin="10px 0">
<Grid>
<TextBlock FontSize="18" FontFamily="xkcd" VerticalAlignment="Top" HorizontalAlignment="Left">Amount of <LineBreak></LineBreak>black ink <LineBreak></LineBreak>by panel:</TextBlock>
<Image x:Name="imgSecondPanel"></Image>
</Grid>
</Border>
<Border Grid.Column="2" x:Name="bThirdPanel" BorderBrush="Black" BorderThickness="3" Padding="10px" Margin="10px 0 0 0">
<Grid>
<TextBlock FontSize="18" FontFamily="xkcd" VerticalAlignment="Top" HorizontalAlignment="Left">Location of <LineBreak></LineBreak>black ink <LineBreak></LineBreak>in this window:</TextBlock>
<Image x:Name="imgThirdPanel"></Image>
</Grid>
</Border>
</Grid>
</Window>
Code:
using System;
using System.Drawing;
using System.Timers;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using Brushes = System.Drawing.Brushes;
namespace WpfApplication1
{
public partial class MainWindow : Window
{
private Timer mainTimer = new Timer();
public MainWindow()
{
InitializeComponent();
{
mainTimer = new Timer(1000/10);
mainTimer.Elapsed += (o, e) => {
try
{
Dispatcher.Invoke(Refresh);
} catch(Exception ex)
{
// Nope
}
};
mainTimer.Start();
};
}
private void Refresh()
{
var actualh = this.RenderSize.Height;
var actualw = this.RenderSize.Width;
var renderTarget = new RenderTargetBitmap((int) actualw, (int) actualh, 96, 96, PixelFormats.Pbgra32);
var sourceBrush = new VisualBrush(this);
var visual = new DrawingVisual();
var context = visual.RenderOpen();
// Render the window onto the target bitmap
using (context)
{
context.DrawRectangle(sourceBrush, null, new Rect(0,0, actualw, actualh));
}
renderTarget.Render(visual);
// Create an array with all of the pixel data
var stride = (int) actualw*4;
var data = new byte[stride * (int)actualh];
renderTarget.CopyPixels(data, stride, 0);
var blackness = 0f;
var total = 0f;
var blacknessFirstPanel = 0f;
var blacknessSecondPanel = 0f;
var blacknessThirdPanel = 0f;
var totalFirstPanel = 0f;
var totalSecondPanel = 0f;
var totalThirdPanel = 0f;
// Count all of the things
for (var i = 0; i < data.Length; i += 4)
{
var b = data[i];
var g = data[i + 1];
var r = data[i + 2];
if (r == 0 && r == g && g == b)
{
blackness += 1;
total += 1;
var x = i%(actualw*4) / 4;
if(x < actualw / 3f)
{
blacknessFirstPanel += 1;
totalFirstPanel += 1;
} else if (x < actualw * (2f / 3f))
{
blacknessSecondPanel += 1;
totalSecondPanel += 1;
}
else if (x < actualw)
{
blacknessThirdPanel += 1;
totalThirdPanel += 1;
}
} else if (r == 255 && r == g && g == b)
{
total += 1;
var x = i % (actualw * 4) / 4;
if (x < actualw / 3f)
{
totalFirstPanel += 1;
}
else if (x < actualw * (2f / 3f))
{
totalSecondPanel += 1;
}
else if (x < actualw)
{
totalThirdPanel += 1;
}
}
}
var black = blackness/total;
Redraw(black, blacknessFirstPanel, blacknessSecondPanel, blacknessThirdPanel, blackness, renderTarget);
}
private void Redraw(double black, double firstpanel, double secondpanel, double thirdpanel, double totalpanels, ImageSource window)
{
DrawPieChart(black);
DrawBarChart(firstpanel, secondpanel, thirdpanel, totalpanels);
DrawImage(window);
}
void DrawPieChart(double black)
{
var w = (float)bFirstPanel.ActualWidth;
var h = (float)bFirstPanel.ActualHeight;
var b = new Bitmap((int)w, (int)h);
var g = Graphics.FromImage(b);
var pw = w - (2*px);
var ph = h - (2*py);
g.DrawEllipse(Pens.Black, px,py,pw,ph);
g.FillPie(Brushes.Black, px, py, pw, ph, 120, (float)black * 360);
g.DrawLine(Pens.Black, 30f, h * 0.1f, w / 2 + w * 0.1f, h / 2 - h * 0.1f);
g.DrawLine(Pens.Black, 30f, h - h * 0.1f, w / 2 - w * 0.2f, h / 2 + h * 0.2f);
imgFirstPanel.Source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(b.GetHbitmap(), IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromWidthAndHeight(b.Width, b.Height));
}
void DrawBarChart(double b1, double b2, double b3, double btotal)
{
var w = (float)bFirstPanel.ActualWidth;
var h = (float)bFirstPanel.ActualHeight;
var b = new Bitmap((int)w, (int)h);
var g = Graphics.FromImage(b);
var px = padding * w;
var py = padding * h;
var pw = w - (2 * px);
var ph = h - (2 * py);
g.DrawLine(Pens.Black, px, py, px, ph+py);
g.DrawLine(Pens.Black, px, py + ph, px+pw, py+ph);
var fdrawbar = new Action<int, double>((number, value) =>
{
var height = ph*(float) value/(float) btotal;
var width = pw/3f - 4f;
var x = px + (pw/3f)*(number-1);
var y = py + (ph - height);
g.FillRectangle(Brushes.Black, x, y, width, height);
});
fdrawbar(1, b1);
fdrawbar(2, b2);
fdrawbar(3, b3);
imgSecondPanel.Source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(b.GetHbitmap(), IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromWidthAndHeight(b.Width, b.Height));
}
void DrawImage(ImageSource window)
{
imgThirdPanel.Source = window;
}
}
}
The code isn't cleaned up, but it should be somewhat readable, sorry.
• A late entry, but one of the best. – primo Jun 14 '14 at 4:10
## C (with SDL and SDL_ttf): Grayscale solution
Here's a solution that takes advantage of the pie chart form to capture the complete spectrum of grayscale pixel colors, clocking in at just under 100 lines.
#include <stdio.h>
#include <string.h>
#include <math.h>
#include "SDL.h"
#include "SDL_ttf.h"
int main(void)
{
SDL_Surface *screen, *buffer, *caption;
SDL_Color pal[256];
SDL_Rect rect;
SDL_Event event;
TTF_Font *font;
int levels[256], plev[256];
Uint8 *p;
float g;
int cr, redraw, hoffset, h, n, v, w, x, y;
SDL_Init(SDL_INIT_VIDEO);
TTF_Init();
screen = SDL_SetVideoMode(640, 480, 0, SDL_ANYFORMAT | SDL_RESIZABLE);
font = TTF_OpenFont(FONTPATH, 24);
buffer = 0;
for (;;) {
if (!buffer) {
buffer = SDL_CreateRGBSurface(SDL_SWSURFACE, screen->w, screen->h,
8, 0, 0, 0, 0);
for (n = 0 ; n < 256 ; ++n)
pal[n].r = pal[n].g = pal[n].b = n;
SDL_SetColors(buffer, pal, 0, 256);
}
memcpy(plev, levels, sizeof levels);
memset(levels, 0, sizeof levels);
SDL_LockSurface(buffer);
p = buffer->pixels;
for (h = 0 ; h < buffer->h ; ++h) {
for (w = 0 ; w < buffer->w ; ++w)
++levels[p[w]];
p += buffer->pitch;
}
for (n = 1 ; n < 256 ; ++n)
levels[n] += levels[n - 1];
redraw = memcmp(levels, plev, sizeof levels);
if (redraw) {
SDL_UnlockSurface(buffer);
SDL_FillRect(buffer, NULL, 255);
"Distribution of pixel color in this image",
pal[0], pal[255]);
rect.x = (buffer->w - caption->w) / 2;
rect.y = 4;
hoffset = caption->h + 4;
SDL_BlitSurface(caption, NULL, buffer, &rect);
SDL_FreeSurface(caption);
SDL_LockSurface(buffer);
cr = buffer->h - hoffset;
cr = (cr < buffer->w ? cr : buffer->w) / 2 - 4;
p = buffer->pixels;
for (h = 0 ; h < buffer->h ; ++h) {
y = h - (screen->h + hoffset) / 2;
for (w = 0 ; w < buffer->w ; ++w) {
x = w - buffer->w / 2;
g = sqrtf(x * x + y * y);
if (g < cr - 1) {
g = atanf((float)y / (x + g));
v = levels[255] * (g / M_PI + 0.5);
for (n = 0 ; n < 255 && levels[n] < v ; ++n) ;
p[w] = n;
} else if (g < cr + 1) {
p[w] = (int)(128.0 * fabs(g - cr));
}
}
p += buffer->pitch;
}
}
SDL_UnlockSurface(buffer);
SDL_BlitSurface(buffer, NULL, screen, NULL);
SDL_UpdateRect(screen, 0, 0, 0, 0);
if (redraw ? SDL_PollEvent(&event) : SDL_WaitEvent(&event)) {
if (event.type == SDL_QUIT)
break;
if (event.type == SDL_VIDEORESIZE) {
SDL_SetVideoMode(event.resize.w, event.resize.h, 0,
SDL_ANYFORMAT | SDL_RESIZABLE);
SDL_FreeSurface(buffer);
buffer = 0;
}
}
}
SDL_Quit();
TTF_Quit();
return 0;
}
As with my previous solution, the path to the font file needs to be either hardcoded in the source or added to the build command, e.g.:
gcc -Wall -o xkcdgolf sdl-config --cflags
-DFONTPATH=fc-match --format='"%{file}"' :bold
xkcdgolf.c -lSDL_ttf sdl-config --libs -lm
The output of the program looks like this:
This one is fun to watch, because all the math slows down the redraws to where you can see the program zero in on the stable solution. The first estimate is wildly off (since the surface starts out all-black), and then shrinks down to the final size after about a dozen or so iterations.
The code works by taking a population count of each pixel color in the current image. If this population count doesn't match the last one, then it redraws the image. The code iterates over every pixel, but it transforms the x,y coordinates into polar coordinates, computing first the radius (using the center of the image as the origin). If the radius is within the pie chart area, it then computes the theta. The theta is easily scaled to the population counts, which determines the pixel color. On the other hand, if the radius is right on the border of the pie chart, then an anti-aliased value is computed to draw the circle around the outside of the chart. Polar coordinates make everything easy!
• You're mostly using the float versions of math-library functions, but then shouldn't fabs be fabsf? – luser droog Jul 22 '13 at 2:08
• Technically, perhaps, but fabs() is more portable. – breadbox Jul 22 '13 at 2:57
• True, I've had trouble with that one not being defined in headers even when present in the library. Also there's less performance to be gained than with the transcendentals. :) – luser droog Jul 22 '13 at 3:16
## C (with SDL and SDL_ttf)
Here's a very simple implementation, in about 60 lines of C code:
#include <stdio.h>
#include "SDL.h"
#include "SDL_ttf.h"
int main(void)
{
char buf[64];
SDL_Surface *screen, *text;
SDL_Rect rect;
SDL_Color black;
SDL_Event event;
TTF_Font *font;
Uint32 blackval, *p;
int size, b, prevb, h, i;
SDL_Init(SDL_INIT_VIDEO);
TTF_Init();
screen = SDL_SetVideoMode(640, 480, 32, SDL_ANYFORMAT | SDL_RESIZABLE);
font = TTF_OpenFont(FONTPATH, 32);
black.r = black.g = black.b = 0;
blackval = SDL_MapRGB(screen->format, 0, 0, 0);
b = -1;
for (;;) {
prevb = b;
b = 0;
SDL_LockSurface(screen);
p = screen->pixels;
for (h = screen->h ; h ; --h) {
for (i = 0 ; i < screen->w ; ++i)
b += p[i] == blackval;
p = (Uint32*)((Uint8*)p + screen->pitch);
}
SDL_UnlockSurface(screen);
size = screen->w * screen->h;
SDL_FillRect(screen, NULL, SDL_MapRGB(screen->format, 255, 255, 255));
sprintf(buf, "This image is %.2f%% black pixels", (100.0 * b) / size);
text = TTF_RenderText_Solid(font, buf, black);
rect.x = (screen->w - text->w) / 2;
rect.y = screen->h / 2 - text->h;
SDL_BlitSurface(text, NULL, screen, &rect);
SDL_FreeSurface(text);
sprintf(buf, "and %.2f%% white pixels.", (100.0 * (size - b)) / size);
text = TTF_RenderText_Solid(font, buf, black);
rect.x = (screen->w - text->w) / 2;
rect.y = screen->h / 2;
SDL_BlitSurface(text, NULL, screen, &rect);
SDL_FreeSurface(text);
SDL_UpdateRect(screen, 0, 0, 0, 0);
if (b == prevb ? SDL_WaitEvent(&event) : SDL_PollEvent(&event)) {
if (event.type == SDL_QUIT)
break;
if (event.type == SDL_VIDEORESIZE)
SDL_SetVideoMode(event.resize.w, event.resize.h, 32,
SDL_ANYFORMAT | SDL_RESIZABLE);
}
}
TTF_Quit();
SDL_Quit();
return 0;
}
To compile this, you need to define FONTPATH to point to a .ttf file of the font to use:
gcc -Wall -o xkcdgolf sdl-config --cflags
-DFONTPATH='"/usr/share/fonts/truetype/freefont/FreeSansBold.ttf"'
xkcdgolf.c -lSDL_ttf sdl-config --libs
On most modern Linux machines you can use the fc-match utility to look up font locations, so the compile command becomes:
gcc -Wall -o xkcdgolf sdl-config --cflags
-DFONTPATH=fc-match --format='"%{file}"' :bold
xkcdgolf.c -lSDL_ttf sdl-config --libs
(Of course you can replace the requested font with your personal favorite.)
The code specifically requests no anti-aliasing, so that the window contains only black and white pixels.
Finally, I was inspired by @daniero's elegant solution to permit window resizing. You'll see that sometimes the program oscillates between counts, stuck in an orbit around an attractor it can never reach. When that happens, just resize the window a bit until it stops.
And, per request, here's what it looks like when I run it on my system:
Finally, I feel that I should point out, in case anyone here hasn't already seen it, that the MAA published an interview with Randall Munroe in which he discusses the making of cartoon #688 in some detail.
• Very nice solution. Could you possibly put in some screenshots of the program running, following off of @daniero's post? :) – Alex Brooks Jul 12 '13 at 14:36
• +1, very nice! Thanks for adding the screenshot :) And the interview link is interesting, thanks! – WendiKidd Jul 12 '13 at 21:24
The image is 100x100 and the numbers are exact, and I do mean exact - I chose a 10000 pixel image so that the percentages could be expressed with two decimal places. The method was a bit of math, a bit of guessing, and some number crunching in Python.
Seeing as I knew in advance that the percentages could be expressed in 4 digits, I counted how many black pixels were in each of the digits 0 through 9, in 8 pixel high Arial, which is what the text is written in. I wrote a quick function weight which tells you how many pixels are needed to write a given number, left padded with zeros to have 4 digits:
def weight(x):
total = 4 * px[0]
while x > 0:
total = total - px[0] + px[x % 10]
x = x / 10
px is an array mapping digits to number of required pixels. If B is the number of black pixels, and W is the number of white pixels, we have B + W = 10000, and we need:
B = 423 + weight(B) + weight(W)
W = 9577 - weight(B) - weight(W)
Where did the constants come from? 423 is the "initial" number of black pixels, the number of black pixels in the text without the numbers. 9577 is the number of initial white pixels. I had to adjust the amount of initial black pixels several times before I managed to get constants such that the above system even has a solution. This was done by guessing and crossing my fingers.
The above system is horribly non-linear, so obviously you can forget about solving it symbolically, but what you can do is just loop through every value of B, set W = 10000 - B, and check the equations explicitly.
>>> for b in range(10000 + 1):
... if b == weight(b) + weight(10000 - b)+423: print b;
...
562
564
• Maybe do a 250 x 400 image so you can get it to 3 decimal places and display more text in the meantime. – Joe Z. Mar 21 '14 at 18:31
• Very nice solution, some brute force math can always solve this kind of problems! – CCP Mar 22 '14 at 16:59
# QBasic
Because nostalgia.
And because I don't really know any image libraries is modern languages.
SCREEN 9
CONST screenWidth = 640
CONST screenHeight = 350
CONST totalPixels# = screenWidth * screenHeight
accuracy = 6
newWhite# = 0
newGreen# = 0
newBlack# = totalPixels#
DO
CLS
white# = newWhite#
green# = newGreen#
black# = newBlack#
' Change the precision of the percentages every once in a while
' This helps in finding values that converge
IF RND < .1 THEN accuracy = INT(RND * 4) + 2
format$= "###." + LEFT$("######", accuracy) + "%"
' Display text
LOCATE 1
PRINT "Percentage of the screen which is white:";
PRINT USING format$; pct(white#) LOCATE 4 PRINT white#; "/"; totalPixels#; "pixels" LOCATE 7 PRINT "Percentage of the screen which is black:"; PRINT USING format$; pct(black#)
LOCATE 10
PRINT black#; "/"; totalPixels#; "pixels"
LOCATE 13
PRINT "Percentage of the screen which is green:";
PRINT USING format$; pct(green#) LOCATE 16 PRINT green#; "/"; totalPixels#; "pixels" ' Display bar graphs LINE (0, 16)-(pct(white#) / 100 * screenWidth, 36), 2, BF LINE (0, 100)-(pct(black#) / 100 * screenWidth, 120), 2, BF LINE (0, 184)-(pct(green#) / 100 * screenWidth, 204), 2, BF newBlack# = pixels#(0) newGreen# = pixels#(2) newWhite# = pixels#(15) LOOP UNTIL black# = newBlack# AND white# = newWhite# AND green# = newGreen# ' Wait for user keypress before ending program: otherwise the "Press any ' key to continue" message would instantly make the results incorrect! x$ = INPUT$(1) FUNCTION pixels# (colr) ' Counts how many pixels of the given color are on the screen pixels# = 0 FOR i = 0 TO screenWidth - 1 FOR j = 0 TO screenHeight - 1 IF POINT(i, j) = colr THEN pixels# = pixels# + 1 NEXT j NEXT i END FUNCTION FUNCTION pct (numPixels#) ' Returns percentage, given a number of pixels pct = numPixels# / totalPixels# * 100 END FUNCTION Pretty straightforward output-count-repeat method. The main "interesting" thing is that the program randomly tries different precisions for the percentages--I found that it didn't always converge otherwise. And the output (tested on QB64): # AWK ## ... with netpbm and other helpers The 'x' file: BEGIN { FS="" n++ while(n!=m) { c="printf '%s\n' '"m"% black pixels'" c=c" '"100-m"% white pixels'" c=c" | pbmtext -space 1 -lspace 1 | pnmtoplainpnm | tee x.pbm" n=m delete P nr=0 while(c|getline==1) if(++nr>2) for(i=1;i<=NF;i++) P[$i]++
close(c)
m=100*P[1]/(P[0]+P[1])
print m"%"
}
}
The run:
\$ awk -f x
4.44242%
5.2424%
5.04953%
5.42649%
5.27746%
5.1635%
5.15473%
5.20733%
5.20733%
The picture is written as 'x.pbm', I converted it to png for uploading:
|
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.36883455514907837, "perplexity": 6734.510445573196}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-04/segments/1547583660175.18/warc/CC-MAIN-20190118151716-20190118173716-00014.warc.gz"}
|
https://www.arxiv-vanity.com/papers/0812.0267/
|
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH
CERN-PH-EP/2008-016
14 October 2008
Search for Charged Higgs Bosons
in Collisions at GeV
The OPAL Collaboration
Abstract
A search is made for charged Higgs bosons predicted by Two-Higgs-Doublet extensions of the Standard Model (2HDM) using electron-positron collision data collected by the OPAL experiment at GeV, corresponding to an integrated luminosity of approximately 600 . Charged Higgs bosons are assumed to be pair-produced and to decay into , or . No signal is observed. Model-independent limits on the charged Higgs-boson production cross section are derived by combining these results with previous searches at lower energies. Excluded areas on the plane are presented assuming . Under the above assumption, motivated by general 2HDM type II models, charged Higgs bosons are excluded up to a mass of 76.6 GeV at 95% confidence level, independent of the branching ratio . A scan of the 2HDM type I model parameter space is performed and limits on the Higgs-boson masses and are presented for different choices of .
Submitted to Eur. Phys. J. C
The OPAL Collaboration
G. Abbiendi, C. Ainsley, P.F. Åkesson, G. Alexander, G. Anagnostou, K.J. Anderson, S. Asai, D. Axen, I. Bailey, E. Barberio, T. Barillari, R.J. Barlow, R.J. Batley, P. Bechtle, T. Behnke, K.W. Bell, P.J. Bell, G. Bella, A. Bellerive, G. Benelli, S. Bethke, O. Biebel, O. Boeriu, P. Bock, M. Boutemeur, S. Braibant, R.M. Brown, H.J. Burckhart, S. Campana, P. Capiluppi, R.K. Carnegie, A.A. Carter, J.R. Carter, C.Y. Chang, D.G. Charlton, C. Ciocca, A. Csilling, M. Cuffiani, S. Dado, M. Dallavalle, A. De Roeck, E.A. De Wolf, K. Desch, B. Dienes, J. Dubbert, E. Duchovni, G. Duckeck, I.P. Duerdoth, E. Etzion, F. Fabbri, P. Ferrari, F. Fiedler, I. Fleck, M. Ford, A. Frey, P. Gagnon, J.W. Gary, C. Geich-Gimbel, G. Giacomelli, P. Giacomelli, M. Giunta, J. Goldberg, E. Gross, J. Grunhaus, M. Gruwé, A. Gupta, C. Hajdu, M. Hamann, G.G. Hanson, A. Harel, M. Hauschild, C.M. Hawkes, R. Hawkings, G. Herten, R.D. Heuer, J.C. Hill, D. Horváth, P. Igo-Kemenes, K. Ishii, H. Jeremie, P. Jovanovic, T.R. Junk, J. Kanzaki, D. Karlen, K. Kawagoe, T. Kawamoto, R.K. Keeler, R.G. Kellogg, B.W. Kennedy, S. Kluth, T. Kobayashi, M. Kobel, S. Komamiya, T. Krämer, A. Krasznahorkay Jr., P. Krieger, J. von Krogh, T. Kuhl, M. Kupper, G.D. Lafferty, H. Landsman, D. Lanske, D. Lellouch, J. Letts, L. Levinson, J. Lillich, S.L. Lloyd, F.K. Loebinger, J. Lu, A. Ludwig, J. Ludwig, W. Mader, S. Marcellini, A.J. Martin, T. Mashimo, P. Mättig, J. McKenna, R.A. McPherson, F. Meijers, W. Menges, F.S. Merritt, H. Mes, N. Meyer, A. Michelini, S. Mihara, G. Mikenberg, D.J. Miller, W. Mohr, T. Mori, A. Mutter, K. Nagai, I. Nakamura, H. Nanjo, H.A. Neal, S.W. O’Neale, A. Oh, A. Okpara, M.J. Oreglia, S. Orito, C. Pahl, G. Pásztor, J.R. Pater, J.E. Pilcher, J. Pinfold, D.E. Plane, O. Pooth, M. Przybycień, A. Quadt, K. Rabbertz, C. Rembser, P. Renkel, J.M. Roney, A.M. Rossi, Y. Rozen, K. Runge, K. Sachs, T. Saeki, E.K.G. Sarkisyan, A.D. Schaile, O. Schaile, P. Scharff-Hansen, J. Schieck, T. Schörner-Sadenius, M. Schröder, M. Schumacher, R. Seuster, T.G. Shears, B.C. Shen, P. Sherwood, A. Skuja, A.M. Smith, R. Sobie, S. Söldner-Rembold, F. Spano, A. Stahl, D. Strom, R. Ströhmer, S. Tarem, M. Tasevsky, R. Teuscher, M.A. Thomson, E. Torrence, D. Toya, I. Trigger, Z. Trócsányi, E. Tsur, M.F. Turner-Watson, I. Ueda, B. Ujvári, C.F. Vollmer, P. Vannerem, R. Vértesi, M. Verzocchi, H. Voss, J. Vossebeld, C.P. Ward, D.R. Ward, P.M. Watkins, A.T. Watson, N.K. Watson, P.S. Wells, T. Wengler, N. Wermes, G.W. Wilson, J.A. Wilson, G. Wolf, T.R. Wyatt, S. Yamashita, D. Zer-Zion, L. Zivkovic
School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, UK
Dipartimento di Fisica dell’ Università di Bologna and INFN, I-40126 Bologna, Italy
Physikalisches Institut, Universität Bonn, D-53115 Bonn, Germany
Department of Physics, University of California, Riverside CA 92521, USA
Cavendish Laboratory, Cambridge CB3 0HE, UK
Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6, Canada
CERN, European Organisation for Nuclear Research, CH-1211 Geneva 23, Switzerland
Enrico Fermi Institute and Department of Physics, University of Chicago, Chicago IL 60637, USA
Fakultät für Physik, Albert-Ludwigs-Universität Freiburg, D-79104 Freiburg, Germany
Physikalisches Institut, Universität Heidelberg, D-69120 Heidelberg, Germany
Indiana University, Department of Physics, Bloomington IN 47405, USA
Queen Mary and Westfield College, University of London, London E1 4NS, UK
Technische Hochschule Aachen, III Physikalisches Institut, Sommerfeldstrasse 26-28, D-52056 Aachen, Germany
University College London, London WC1E 6BT, UK
School of Physics and Astronomy, Schuster Laboratory, The University of Manchester M13 9PL, UK
Department of Physics, University of Maryland, College Park, MD 20742, USA
Laboratoire de Physique Nucléaire, Université de Montréal, Montréal, Québec H3C 3J7, Canada
University of Oregon, Department of Physics, Eugene OR 97403, USA
Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, UK
Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel
Department of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
International Centre for Elementary Particle Physics and Department of Physics, University of Tokyo, Tokyo 113-0033, and Kobe University, Kobe 657-8501, Japan
Particle Physics Department, Weizmann Institute of Science, Rehovot 76100, Israel
Universität Hamburg/DESY, Institut für Experimentalphysik, Notkestrasse 85, D-22607 Hamburg, Germany
University of Victoria, Department of Physics, P O Box 3055, Victoria BC V8W 3P6, Canada
University of British Columbia, Department of Physics, Vancouver BC V6T 1Z1, Canada
University of Alberta, Department of Physics, Edmonton AB T6G 2J1, Canada
Research Institute for Particle and Nuclear Physics, H-1525 Budapest, P O Box 49, Hungary
Institute of Nuclear Research, H-4001 Debrecen, P O Box 51, Hungary
Ludwig-Maximilians-Universität München, Sektion Physik, Am Coulombwall 1, D-85748 Garching, Germany
Max-Planck-Institute für Physik, Föhringer Ring 6, D-80805 München, Germany
Yale University, Department of Physics, New Haven, CT 06520, USA
and at TRIUMF, Vancouver, Canada V6T 2A3
now at University of Alberta
and Institute of Nuclear Research, Debrecen, Hungary
now at Institute of Physics, Academy of Sciences of the Czech Republic 18221 Prague, Czech Republic
and Department of Experimental Physics, University of Debrecen, Hungary
and MPI München
and Research Institute for Particle and Nuclear Physics, Budapest, Hungary
now at University of Liverpool, Dept of Physics, Liverpool L69 3BX, U.K.
now at Dept. Physics, University of Illinois at Urbana-Champaign, U.S.A.
now at University of Texas at Arlington, Department of Physics, Arlington TX, 76019, U.S.A.
now at University of Kansas, Dept of Physics and Astronomy, Lawrence, KS 66045, U.S.A.
now at University of Toronto, Dept of Physics, Toronto, Canada
current address Bergische Universität, Wuppertal, Germany
now at University of Mining and Metallurgy, Cracow, Poland
now at University of California, San Diego, U.S.A.
now at The University of Melbourne, Victoria, Australia
now at IPHE Université de Lausanne, CH-1015 Lausanne, Switzerland
now at IEKP Universität Karlsruhe, Germany
now at University of Antwerpen, Physics Department,B-2610 Antwerpen, Belgium; supported by Interuniversity Attraction Poles Programme – Belgian Science Policy
now at Technische Universität, Dresden, Germany
and High Energy Accelerator Research Organisation (KEK), Tsukuba, Ibaraki, Japan
now at University of Pennsylvania, Philadelphia, Pennsylvania, USA
now at Columbia University
now at CERN
now at DESY
Deceased
## 1 Introduction
In the Standard Model (SM) [1], the electroweak symmetry is broken via the Higgs mechanism [2] generating the masses of elementary particles. This requires the introduction of a complex scalar Higgs-field doublet and implies the existence of a single neutral scalar particle, the Higgs boson. While the SM accurately describes the interactions between elementary particles, it leaves several fundamental questions unanswered. Therefore, it is of great interest to study extended models.
The minimal extension of the SM Higgs sector required, for example, by supersymmetric models contains two Higgs-field doublets [3] resulting in five Higgs bosons: two charged () and three neutral. If CP-conservation is assumed, the three neutral Higgs bosons are CP-eigenstates: h and H are CP-even and A is CP-odd. Two-Higgs-Doublet Models (2HDMs) are classified according to the Higgs-fermion coupling structure. In type I models (2HDM(I)) [4], all quarks and leptons couple to the same Higgs doublet, while in type II models (2HDM(II)) [5], down-type fermions couple to the first Higgs doublet, and up-type fermions to the second.
Charged Higgs bosons are expected to be pair-produced in the process at LEP, the reaction W having a much lower cross section [6]. In 2HDMs, the tree-level cross section [7] for pair production is completely determined by the charged Higgs-boson mass and known SM parameters.
The branching ratios are model-dependent. In most of the 2HDM(II) parameter space, charged Higgs bosons decay into the heaviest kinematically allowed fermions, namely and quark pairs111 Throughout this paper charge conjugation is implied. For simplicity, the notation stands for and and for a quark and anti-quark of any flavor.. The situation changes in 2HDM(I), where the decay A can become dominant if the ratio of the vacuum expectation values of the two Higgs-field doublets 1 and the A boson is sufficiently light [8].
In this paper we search for charged Higgs bosons decaying into , and A using the data collected by the OPAL Collaboration in 19982000. The results are interpreted within general 2HDM(II) assuming for the branching ratios and in 2HDM(I) taking into account decays of charged Higgs bosons via A, as well. Our result is not confined to ={cs̄, c̄s} although that is the dominant hadronic decay channel in most of the parameter space.
The previously published OPAL lower limit on the charged Higgs-boson mass, under the assumption of , is GeV at 95% confidence level (CL) using data collected at GeV [9, 10]. Lower bounds of GeV have been reported by the other LEP collaborations [11, 12, 13] based on the full LEP2 data set. The DELPHI Collaboration also performed a search for decay and constrained the charged Higgs-boson mass in 2HDM(I) [12] to be 76.7 GeV at 95%CL.
## 2 Experimental considerations
The OPAL detector is described in [14]. The events are reconstructed from charged-particle tracks and energy deposits (clusters) in the electromagnetic and hadron calorimeters. The tracks and clusters must pass a set of quality requirements similar to those used in previous OPAL Higgs-boson searches [15]. In calculating the total visible energies and momenta of events and individual jets, corrections are applied to prevent double-counting of energy in the case of tracks and associated clusters [15].
The data analyzed in this paper were collected in 19982000 at center-of-mass energies of GeV as given in Table 1. Due to different requirements on the operational state of the OPAL subdetectors, the integrated luminosity of about 600 differs slightly among search channels.
In this paper the following final states are sought:
• (two-tau final state, ),
• (two-jet plus tau final state, ),
• (four-jet final state, ),
• (eight-jet final state, ),
• (six-jet plus lepton final state, ),
• (four-jet plus tau final state, ).
The signal detection efficiencies and accepted background cross sections are estimated using a variety of Monte Carlo samples. The HZHA generator [16] is used to simulate production at fixed values of the charged Higgs-boson mass in steps of GeV from the kinematic limit down to 50 GeV for fermionic decays and 40 GeV for bosonic decays.
The background processes are simulated primarily by the following event generators: PYTHIA [17] and KK2F [18] (Z/()), grc4f [19] (four-fermion processes, 4f), BHWIDE [20] and TEEGG [21] (), KORALZ [22] and KK2F ( and ), PHOJET [23], HERWIG [24], Vermaseren [25] (hadronic and leptonic two-photon processes).
The generated partons, both for the signal and the SM Monte Carlo simulations, are hadronized using JETSET [17], with parameters described in [26]. For systematic studies, cluster fragmentation implemented in HERWIG for the process Z/() is used. The predictions of 4f processes are cross-checked using EXCALIBUR [27], KoralW [28] and KandY [29].
The obtained Monte Carlo samples are processed through a full simulation of the OPAL detector [30]. The event selection is described below.
## 3 Search for four-fermion final states
In most of the parameter space of 2HDM(II) and with a sufficiently heavy A boson in 2HDM(I), the fermionic decays of the charged Higgs boson dominate and lead to four-fermion final states. The most important decay mode is typically , with the hadronic mode reaching about 40% branching ratio at maximum.
The search for the fully leptonic final state is described in [31]. The searches for the and the events are optimized using Monte Carlo simulation of decays. The sensitivities to other quark flavors are similar and the possible differences are taken into account as systematic uncertainties. Therefore, our results are valid for any hadronic decay of the charged Higgs boson.
Four-fermion final states originating from production would have very similar kinematic properties to production, which therefore constitutes an irreducible background to our searches, especially when is close to . To suppress this difficult SM background, a mass-dependent likelihood selection (similar to the technique described in [32]) is introduced. For each charged Higgs-boson mass tested (), a specific analysis optimized for a reference mass () close to the hypothesized value is used.
We have chosen a set of reference charged Higgs-boson masses at which signal samples are generated. Around these reference points, mass regions (labeled by ) are defined with the borders centered between the neighboring points. For each individual mass region, at each center-of-mass energy, we create a separate likelihood selection with the signal histograms built using events generated at . The background histograms are composed of the SM processes and are identical for all mass regions.
When testing the hypothesis of a signal with mass , the background and data rate and discriminant (i.e. the reconstructed Higgs-boson mass) distribution depend on the mass region to which belongs. The signal quantities depend on the value of itself and are determined as follows. The signal rate and discriminant distribution are computed, with the likelihood selection optimized for , for three simulated signal samples with masses , and . Here, and are the closest mass points to at which signal Monte Carlo samples are generated, with . The signal rate and discriminant distribution for are then calculated by linear interpolation from the quantities for and if , or for and if .
When building the likelihood function three event classes are considered: signal, four-fermion background and two-fermion background. The likelihood output gives the probability that a given event belongs to the signal rather than to one of the two background sources.
### 3.1 The two-jet plus tau final state
The analysis closely follows our published one at GeV [10]. It proceeds in two steps. First, events consistent with the final state topology of an isolated tau lepton, a pair of hadronic jets and sizable missing energy are preselected and are then processed by a likelihood selection. The sensitivity of the likelihood selection is improved by building mass-dependent discriminant functions as explained above.
Events are selected if their likelihood output () is greater than a cut value chosen to maximize the sensitivity of the selection at each simulated charged Higgs-boson mass. Apart from the neighborhood of the peak, the optimal cut does not depend significantly on the simulated mass and is chosen to be 0.85. Around the peak, it is gradually reduced to 0.6 at the lowest.
At the end of the selection, 331 events are selected in the data sample with (stat.) (syst.) events expected from SM processes for a test mass of =75 GeV. The sources of systematic uncertainties are discussed below. Four-fermion processes account for more than 99% of the SM background and result in a large peak in the reconstructed mass centered at the mass (with a second peak at the Z mass for test masses of GeV). The signal detection efficiencies for the various LEP energies are between 25% and 53% for any charged Higgs-boson mass.
The likelihood output and reconstructed di-jet mass distributions for simulated Higgs-boson masses of 60 GeV and 75 GeV are presented in Figures 1(a-d). The reconstructed Higgs-boson mass resolution is GeV [10]. Figure 2(a) gives the mass dependence of the expected number of background and signal events and compares them to the observed number of events at each test mass.
The systematic uncertainties are estimated for several choices of the charged Higgs-boson mass from 50 GeV to 90 GeV at center-of-mass energies of =189 GeV, 200 GeV and 206 GeV to cover the full LEP2 range. The following sources of uncertainties are considered: limited number of generated Monte Carlo events, statistical and systematic uncertainty on the luminosity measurement, modeling of kinematic variables in the pre- and likelihood selections, tau lepton identification, dependence of the signal detection efficiency on final-state quark flavor, signal selection efficiency interpolation between generated Monte Carlo points, background hadronization model, and four-fermion background model. The contributions from the different sources are summarized in Table 2.
In the limit calculation, the efficiency and background estimates of the channel are reduced by 0.81.7% (depending on the center-of-mass energy) in order to account for accidental vetoes due to accelerator-related backgrounds in the forward detectors.
### 3.2 The four-jet final state
The event selection follows our published analysis at =183 GeV [10]: first, well-separated four-jet events with large visible energy are preselected; then a set of variables is combined using a likelihood technique. To improve the discriminating power of the likelihood selection, a new reference variable is introduced: the logarithm of the matrix element probability for production averaged over all possible jet-parton assignments computed by EXCALIBUR [27]. Moreover, we introduce mass-dependent likelihood functions as explained above. As the optimal cut value on the likelihood output is not that sensitive to the charged Higgs-boson mass in this search channel, we use the condition 0.45 at all center-of-mass energies and for all test masses.
There is a good agreement between the observed data and the SM Monte Carlo expectations at all stages of the selection. After all cuts, 1100 events are selected in the data, while (stat.) (syst.) events are expected from SM processes for a test mass of =75 GeV. The four-fermion processes account for about 90% of the expected background and result in a large peak centered at the mass and a smaller one at the Z boson mass. The signal detection efficiencies are between 41% and 59% for any test mass and center-of-mass energy.
Typical likelihood output and reconstructed di-jet mass distributions of the selected events together with the SM background expectation and signal shapes for simulated charged Higgs-boson masses of 60 GeV and 75 GeV are plotted in Figures 1(e-h). The Higgs-boson mass can be reconstructed with a resolution of GeV [10]. Figure 2(b) shows the mass dependence of the expected number of background and signal events and compares them to the observed number of events at each test mass. Systematic uncertainties are estimated in the same manner as for the search and are given in Table 2.
## 4 Search for AW+∗AW−∗ events
In a large part of the 2HDM(I) parameter space, the branching ratio of dominates. The possible decay modes of the A boson and the lead to many possible event topologies. Above 12 GeV, the A boson decays predominantly into a pair, and thus its detection is based on b-flavor identification. Two possibilities, covering 90% of the decays of two , are considered: quark pairs from both bosons or a quark pair from one and a leptonic final state from the other. The event topologies are therefore “eight jets” or “six jets and a lepton with missing energy”, with four jets containing b-flavor in both cases.
The background comes from several Standard Model processes. ZZ and production can result in multi-jet events. While ZZ events can contain true b-flavored jets, events are selected as candidates when c-flavored jets fake b-jets. Radiative QCD corrections to also give a significant contribution to the expected background.
Due to the complexity of the eight-parton final state, it is more efficient to use general event properties and variables designed specifically to discriminate against the main background than a full reconstruction of the event. As a consequence, no attempt is made to reconstruct the charged Higgs-boson mass.
The analysis proceeds in two steps. First a preselection is applied to select b-tagged multi-jet events compatible with the signal hypothesis. Then a likelihood selection (with three event classes: signal, four-fermion background and two-fermion background) is applied.
The preselection of multi-jet events uses the same variables as the search for the hadronic final state in [10] with optimized cut positions. However, it introduces a very powerful new criterion, especially against the background, on a combined b-tagging variable () requiring the consistency of the event with the presence of b-quark jets.
The neural network method used for b-tagging in the OPAL SM Higgs-boson search [15] is used to calculate on a jet-by-jet basis the discriminating variables and . These are constructed for each jet as the ratios of probabilities for the jet to be c- or uds-like versus the probability to be b-like. The inputs to the neural network include information about the presence of secondary vertices in a jet, the jet shape, and the presence of leptons with large transverse momentum. The Monte Carlo description of the neural network output was checked with LEP1 data with a jet energy of about 46 GeV. The main background in this search at LEP2 comes from four-fermion processes, in which the mean jet energy is about 50 GeV, very close to the LEP1 jet energy; therefore, an adequate modeling of the data is expected with an event reconstruction assuming four jets.
The signal topology depends on the Higgs-boson masses. At 12 GeV or , the available energy in the A or system is too low to form two clean, collimated jets. At high , the boost of the A and bosons is small in the laboratory frame and the original eight partons cannot be identified. At low , the A and bosons might have a boost, but it is still not possible to resolve correctly the two partons from their decay. From these considerations, one can conclude that it is not useful to require eight (or even six) jets in the event, as these jets will not correspond to the original partons. Consequently, to get the best possible modeling of the data, four jets are reconstructed with the Durham jet-finding algorithm [33] before the b-tagger is run.
The flavor-discriminating variables are combined for the four reconstructed jets by
Bevt=11+α⋅∏ific/b+β⋅∏ifiuds/b (1)
The index runs over the reconstructed jets () and the parameters and are numerical coefficients whose optimal values depend on the flavor composition of the signal and background final states. However, since the expected sensitivity of the search is only slightly dependent on the values of and , they are fixed at and . Events are retained if .
The preselections of the two event topologies ( and ) are very similar. However, in the channel, no kinematic fit is made to the hypothesis and, therefore, no cuts are made on the fit probabilities. No lepton identification is applied; instead the search is based on indirect detection of the associated neutrino by measuring the missing energy.
After the preselection the observed data show an excess over the predicted Monte Carlo background. This can partly be explained by the apparent difference between the gluon splitting rate into cc̄ and bb̄ pairs in the data and in the background Monte Carlo simulation. The measured rates are [34] and [35] from the LEP1 OPAL data. The gluon splitting rates in the Monte Carlo are extracted from events and are found to be and , averaged over all center-of-mass energies. This mismodeling can be compensated by reweighting the SM Monte Carlo events with gluon splitting to heavy quarks by universal reweighting factors [36] and at the same time deweighting the non-split events to keep the total numbers of , and two-fermion background events fixed at generator level. The reweighting factor is 2.41 for gcc̄ and 2.65 for gbb̄. This correction results in a background enhancement factor of 1.08 to 1.1 after the preselection, depending on the search channel and the center-of-mass energy, but it does not affect the shape of the background distributions. The numbers of preselected events after the reweighting are given in Table 3.
As a final selection, likelihood functions are built to identify signal events. The reference distributions depend on the LEP energy, but they are constructed to be independent of the considered combination. To this end, we form the signal reference distributions by averaging all simulated samples in the mass range of interest.
Since the selections at GeV are aimed at charged Higgs-boson masses around the expected sensitivity reach of about 8090 GeV, all masses up to the kinematic limit are included. On the other hand, at =189 GeV only charged Higgs-boson masses up to 50 GeV are included since the selections at this energy are optimized to reach down to as low as a charged Higgs-boson mass of 40 GeV where the LEP1 exclusion limit lies. The input variables for the final state are: the Durham jet-resolution parameters222 Throughout this paper denotes the parameter of the Durham jet finder at which the event classification changes from -jet to -jet, where . and , the oblateness [37] event shape variable, the opening angle of the widest jet defined by the size of the cone containing 68% of the total jet energy, the charge-signed cosine of the production angle in the hypothesis, and the b-tagging variable . At =189 GeV, , , , and the maximum jet energy are also used. Moreover, the sphericity [38] event shape variable has more discriminating power and thus replaces oblateness. Although the variables are somewhat correlated, they contain additional information: their differences reflect the kinematics of the initial partons.
The input variables for the selection are: , , the oblateness, the missing energy of the event, and . At =189 GeV, , the maximum jet energy and the sphericity are also included.
Events are selected if they pass a lower cut on the likelihood output. This final cut does not remove (especially in the year 1999 data) all the excess events observed after the preselection. The distributions of the critical selection variables, , and , are plotted on Figure 3 both in background-enriched data samples and after the preselection. To prepare these background-enriched data samples, the preselection cuts on and are dropped, except for the study of the variable where we keep the cut on in order to select multi-jet events. The resulting samples are completely dominated by background processes. We find systematic differences between the data samples and the equivalent background Monte Carlo simulations at both stages. The observed excess cannot be attributed to a Higgs-boson signal whose contribution is expected to be at most 0.5% in the background-enriched data samples. The interpretation of the excess in terms of a systematic uncertainty on the background prediction will be discussed later.
The non-signal nature of the excess is also demonstrated by Figure 4, which shows the distributions of the likelihood output. The positions of the likelihood cut are indicated by vertical lines.
Because the and the selections have several discriminating variables in common, a major overlap between these selections exists. To assure that every event is counted only once, the two samples are redistributed into three: () events exclusively classified as candidates, () events exclusively classified as candidates and () events accepted by both selections. If an event falls into class (), the larger likelihood output of the two selections is kept for further processing. The final results using the above classification are quoted in Table 3.
This modified channel definition not only removes the overlap but also increases the efficiency for detecting signal events by considering the cross-channel efficiencies (e.g. the efficiency to select signal by the exclusive selection can be as high as 18%, though it is typically only a few %). The efficiencies are determined independently for all simulated combinations and interpolated to arbitrary by two-dimensional spline interpolation. The behavior of the selection efficiencies depends strongly on the targeted charged Higgs-boson mass range and also varies with the mass difference . In most cases the overlap channel has the highest efficiency. At =189 GeV and =45 GeV, it reaches 32% for the and 44% for the signal close to the = diagonal. At =206 GeV and =90 GeV, the overlap efficiency can be as high as 62% for the and 71% for the signal. The exclusive selection has efficiencies typically below 2030%, while the exclusive selection below 1015%. Table 4 gives the selection efficiencies at selected points.
The composition of the background depends on the targeted Higgs-boson mass region. In the low-mass selection (=189 GeV) that is optimized for =4050 GeV, the Higgs bosons are boosted and therefore the final state is two-jet-like with the largest background contribution coming from two-fermion processes: they account for 52% in the exclusive , 80% in the exclusive and 76% in the overlap channel. On the other hand, in the high-mass analysis ( GeV) the four-fermion fraction is dominant: it is 69% in the , 56% in the and 70% in the overlap channel.
Although our studies show that the observed excess does not lie preferentially in the phase space region where the Higgs-boson signal is expected and that it probably originates from deficiencies of the Monte Carlo description of the jet-resolution parameters and the b-tagging variable , no further correction is applied to the estimated background in the background subtraction procedure of the statistical analysis to calculate exclusion limits. This leads to conservative limits on the production cross section. Therefore, no systematic uncertainty is assigned to the modeling of and at the preselection level. The systematic uncertainties related to the other preselection variables, estimated from background-enriched data samples, are taken into account. The effect of mismodeling the shapes of the reference distributions in the likelihood selection is estimated for all variables, including and and is accounted for in the statistical analysis.
Systematic uncertainties arise also due to the gluon splitting correction: the experimental uncertainty on the gluon splitting rate translates into uncertainties on the total background rates. Moreover, the weighted background counting introduces an uncertainty due to the Monte Carlo statistics of the gcc̄ and bb̄ events.
In summary, the following sources of systematic uncertainties are considered: limited number of simulated signal and background events, modeling of the preselection variables (other than and ), modeling of the shapes of the reference distributions in the likelihood selection and the gluon splitting correction. Uncertainties below the 1% level are neglected. The different contributions are summarized in Table 5.
## 5 Search for AW±∗τντ events
In some parts of the 2HDM(I) parameter space, both the fermionic and the bosonic decay modes contribute. To cover this transition region parallel to the diagonal, a search for the final state is performed. The transition region is wide for small and narrow for large ; therefore, this analysis is more relevant for lower values of .
Only the hadronic decays of and the decay A are considered. Thus the events contain a tau lepton, four jets (two of which are b-flavored) and missing energy. Separating the signal from the background becomes difficult close to =.
The preselection is designed to identify hadronic events containing a tau lepton plus significant missing energy and transverse momentum from the undetected neutrino. In most cases it is not practical to reconstruct the four jets originating from the system. Instead, to suppress the main background from semi-leptonic events, we remove the decay products of the tau candidate and force the remaining hadronic system into two jets by the Durham algorithm. The requirements are then based on the preselection of Section 3.1 with additional preselection cuts on the effective center-of-mass energy, and of the hadronic system, and the charge-signed production angle.
The likelihood selection uses seven variables: the momentum of the tau candidate, the cosine of the angle between the tau momentum and the nearest jet, of the hadronic system, the cosine of the angle between the two hadronic jets, the charge-signed cosine of the production angle, the invariant mass of the hadronic system, and the b-tagging variable . Here, is defined using the two jets of the hadronic system using Eq. (1) of Section 4, with and . To form the signal reference distributions, all simulated samples in the mass range of interest are summed up. Since the search at GeV targets intermediate charged Higgs-boson masses (6080 GeV), all masses up to the kinematic limit are included. At =189 GeV, only charged Higgs-boson masses up to 50 GeV are included since the selection is optimized for low charged Higgs-boson masses (4050 GeV).
The likelihood output distributions are shown in Figure 5. There is an overall agreement between data and background distributions, apart from a small discrepancy at 189 GeV. Events are selected if their likelihood output is larger than 0.9. In total, 15 data events survive the selection at GeV, to be compared with (stat.) (syst.) events expected from background sources. At =189 GeV, where the selection is optimized for low Higgs-boson masses, 13 data events are selected with (stat.) (syst.) events expected. The contribution of four-fermion events, predominantly from semi-leptonic production, amounts to 33% at =189 GeV and to 90% at GeV.
At GeV, the signal selection efficiency starts at about 5% at =40 GeV, reaches its maximum of about 40% (depending on the mass difference ) at =60 GeV, then decreases to 12% at =90 GeV. In the low-mass selection at =189 GeV, the efficiency depends strongly on the mass difference: at =40 GeV, it is 22% for GeV and 60% for GeV. The selection efficiency approaches its maximum at =50 GeV (70% for GeV) and then drops to zero at =80 GeV. Table 4 gives selection efficiencies at representative points.
The systematic uncertainties due to the modeling of selection variables are evaluated with the method developed for the channels and summarized in Table 6.
## 6 Interpretation
None of the searches has revealed a signal-like excess over the SM expectation. The results presented here and those published previously [10, 31] by the OPAL Collaboration are combined using the method of [39] to study the compatibility of the observed events with “background-only” and “signal plus background” hypotheses and to derive limits on charged Higgs-boson production. The statistical analysis is based on weighted event counting, with the weights computed from physical observables, also called discriminating variables of the candidate events (see Table 7). Systematic uncertainties with correlations are taken into account in the confidence level (-value) calculations. To improve the sensitivity of the analysis, they are also incorporated into the weight definition [39].
The results are interpreted in two different scenarios: in the traditional, supersymmetry-favored 2HDM(II) (assuming that there are no new additional light particles other than the Higgs bosons) and in the 2HDM(I) where under certain conditions fermionic couplings are suppressed.
First, we calculate , the confidence [39] under the background-only hypothesis, and then proceed to calculate limits on the charged Higgs-boson production cross section in the signal + background hypothesis. These results are used to provide exclusions in the model parameter space, and in particular, on the charged Higgs-boson mass.
### 2HDM Type II
First a general 2HDM(II) is considered, where . This model was thoroughly studied at LEP. It is realized in supersymmetric extensions of the SM if no new additional light particles other than the Higgs bosons are present. As our previously published mass limit in such a model is GeV [10], only charged Higgs-boson masses above 50 GeV are tested. Cross-section limits for lower masses can be found in [9]. In this model, the results of the , and searches enter the statistical combination.
The confidence is plotted for each channel separately in Figure 6(a) and combined in Figure 6(b). Note that translates to negative values of sigma (as indicated by the dual y-axis scales in Figure 6(a)) and indicates an excess of events. The largest deviation, a 2.8 excess observed in the channel at =88 GeV, comes from a known deficiency [40] of the Monte Carlo simulation of isolated tracks from the fragmentation and hadronization process. When the three final states are combined assuming , no deviation reaches the 2 level.
The results are used to set upper bounds on the charged Higgs-boson pair production cross section relative to the 2HDM prediction as calculated by HZHA. The limits obtained are shown for each channel separately in Figures 7(a-c) and combined in Figure 7(d). The combined results are shown by “isolines” along which , the ratio of the limit on the production cross section and the 2HDM cross-section prediction, is equal to the number indicated next to the curves.
Excluded areas on the plane are presented for each channel separately in Figure 8(a) and combined in Figure 8(b). The expected mass limit from simulated background experiments, assuming no signal, is also shown. For the combined results, the 90% and 99% CL contours are also given. Charged Higgs bosons are excluded up to a mass of 76.6 GeV at 95% CL, independent of . Lower mass limits for different values of are presented in Table 8.
### 2HDM Type I
We present here for the first time an interpretation of the OPAL charged Higgs-boson searches in an alternative theoretical scenario, a 2HDM(I). The novel feature of this model with respect to the more frequently studied 2HDM(II) is that the fermionic decays of the charged Higgs boson can be suppressed. If the A boson is light, the decay may play a crucial role.
The charged Higgs-boson sector in these models is described by three parameters: , and . To test this scenario, the charged Higgs-boson decay branching ratios are calculated by the program of Akeroyd et al. [8], and the model parameters are scanned in the range: 40 GeV GeV, 12 GeV , . Charged Higgs-boson pair production is excluded below 40 GeV by the measurement of the Z boson width [41]. As the A boson detection is based on the identification of b-quark jets, no limits are derived for . Below =0.1, vanishes and the limit is no longer sensitive to .
Both the fermionic (, and ) and the bosonic (, and ) final states play an important role and therefore their results are combined. There is, however, a significant overlap between the events selected by the and selections, and the events selected by the and selections. Therefore, an automatic procedure is implemented to switch off the less sensitive of the overlapping channels, based on the calculation of the expected limit assuming no signal. In general the fermionic channels are used close to the diagonal and for low , and the searches for are crucial for low values of and high values of .
The confidence is calculated combining the and searches assuming SM branching ratios [42] for the decay and is shown on Figure 9(a). The largest deviation corresponding to is reached at =45 GeV and =44.9 GeV (in the middle of the very narrow lightest strip from =40 GeV to 50 GeV at the diagonal). However, the mean background shift on the plane amounts only to . for the channel is shown in Figure 9(b). The largest deviation corresponding to appears for low charged Higgs-boson masses (=40 GeV, =21 GeV), reflecting the excess of events in the =189 GeV search. The mean background shift for this channel is 0.8. Note that the results shown in Figures 9(a-b) are model-independent.
When all channels are combined within 2HDM(I), a few hot spots with a significance above survive. This is illustrated in Figures 9(c-d), where the combined results are plotted for =10 and 100. For =10, the largest excess corresponding to is found at =55 GeV and =35 GeV (just before switching from the bosonic to the fermionic channels).
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• anonymous
arnold has taken 4 tests. on the 1st test he scored 83%, on the 2nd he got 85%, and on the 3rd he got 100%. the 4th test is counted double any of the other tests. what score did he get on the 4th test if his final overall average was 90%
Mathematics
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http://mathhelpforum.com/advanced-algebra/146370-interpolation-question.html
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Math Help - Interpolation Question
1. Interpolation Question
4. Set $f(x_n,y_n)= p(x_n, y_n)$ for each of the given pairs!
For example, $f(x_0, y_0)= e^x_0 sin(y_0)$ while $p(x_0, y_0)= c_0+ c_1x_0+ c_2y_0+ c_3x_0y_0+ c_4x_0^2+ c_5y_0^2$ so one of your equations is
$c_0+ c_1x_0+ c_2y_0+ c_3x_0y_0+ c_4x_0^2+ c_5y_0^2= e^x_0sin(y_0)$
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http://mathhelpforum.com/algebra/205313-math-league-contest.html
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1. ## Math league contest
1-2 What is the least integer greater than 1 million whose square root is also an integer?
1-3 What are both integers n for which
(2^n^4)(2^n^3)(2^n^2)(2^n)=1 My answer was 0 and -1.
1-4 The cost(in cents) of 8 candies is equal to the number of candies that I can buy for 98 cents. At the same cost per candy, how many cents do 14 candies cost?
2. ## Re: Math league contest
Hello, victorwen28!
1-2 What is the least integer greater than 1 million whose square root is also an integer?
. . My answer was 1,002,001.
1-3 What are both integers n for which $\left(2^{n^4}\right)\left(2^{n^3}\right)\left(2^{n ^2}\right)\left(2^n\right)\;=\;1$
. . My answer was 0 and -1.
1-4 The cost(in cents) of 8 candies is equal to the number of candies that I can buy for 98 cents.
At the same cost per candy, how many cents do 14 candies cost?
. . My answer was 49 cents.
Good work!
3. ## Re: Math league contest
Thanks a lot!
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https://www.physicsforums.com/threads/energy-and-momentum-problem.898681/
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# Energy and Momentum problem
Tags:
1. Dec 29, 2016
### n1trate
1. The problem statement, all variables and given/known data
Magnetic puck A, with a mass of 0.100 kg, is pushed towards stationary 0.050 kg
magnetic puck B, to cause a head-on collision. You may neglect friction. The initial
velocity of puck A is 12 m/s [E]. Puck B moves with a velocity of 14 m/s [E], after
the collision.
a) Find the velocity of puck A after the collision.
2. Relevant equations
p=mv
pinitial=pfinal
Einitial = Efinal
Ek = 1/2mv^2
3. The attempt at a solution
Basically I understand how to solve the question using the momentum by why is that I get a different velocity when using the energy?
Since friction is neglected, where could this system be losing kinetic energy?
I did Ei=Ef which is Eki=Ekf
1/2(0.100)(12)^2+0=1/2(0.100)v_A^2 + 1/2(0.050)(14)^2
I end up getting 6.8m/s for the final velocity of puck A
But the correct answer is 5.0m/s
I tried to plug that into the equation but I get
7.2J=6.15J which is incorrect. What am I doing wrong here?
2. Dec 29, 2016
### Staff: Mentor
Hi n1trate, Welcome to Physics Forums.
What's the import of the pucks being magnetic? It's not obvious to me, but perhaps there's some mechanism that's not elaborated upon that is responsible for energy being lost. So we're meant to presume that conservation of energy doesn't hold here.
In fact, if you assume a perfectly elastic collision with the given initial conditions you'll find a different final velocity for puck B than they have provided...
3. Dec 29, 2016
### TomHart
Like @gneill said, based on the numbers, it cannot be a perfectly elastic collision, so conservation of energy would not apply. And also like @gneill said, I have no idea what the mention of "magnetic" has to do with the problem. It seems to add no value. What else do you have to work with?
I just realized I ended that last sentence in a preposition, reminding me of a Winston Churchill quote:
"From now on, ending a sentence in a preposition is something up with which I will not put."
4. Dec 30, 2016
### n1trate
They didn't give me anything else actually but the first way that came to my mind to solve this problem was using conservation of energy. They didn't put use momentum explicitly, but thanks for the answers now I understand. It was confusing me all night I thought I was wrong but I guess it's just the question. Thank you!
5. Dec 30, 2016
### Ray Vickson
If (as the question states) the final speed of B is 14 m/s, then energy cannot be conserved. In the so-called "center-of-momentum" (CM) frame we assume that total kinetic energies before and after the collision are related as
$$\text{K.E.}_{\text{final}} = f\: \text{K.E.}_{\text{initial}}$$
for some factor $0 \leq f \leq 1$. We have a perfectly elastic collision if $f=1$, a perfectly inelastic collision if $f = 0$ and something in between if $0 < f < 1$. Anyway, using momentum conservation and the above KE condition, we can easily determine the final velocities of A and B in the CM frame in terms of $f$, then transform those back into the original (lab) frame. We find that there is, indeed, a fractional value of $f$ that makes the final lab-frames speed of B equal to 14 m/s and the final lab-frame speed of A equal to 5 m/s, just as your book claims.
6. Dec 30, 2016
### haruspex
"After the collision" is rather vague. Immediately after the collision some of the energy will be in the form of magnetic potential energy.
7. Dec 30, 2016
### ehild
It is possible, that the pucks do not touch each other during the "collision", if they repel each other due to interaction between their magnetic moments. In this case, loss of the kinetic energy is not caused by the usual way, that they deform each other and some of the kinetic energy transforms into heat and sound.
As they are magnetic and move, they produce varying magnetic field, and varying magnetic field produces changing electric field, so you have time-dependent electromagnetic field that radiates away. The radiation is strongest when the pucks are close to each other, but "before collision" and "after collision" means the state when the pucks are far away. As electromagnetic fields are involved, the mechanical energy does not conserve.
8. Dec 30, 2016
### robphy
First of all, this is a collision problem.
Total-momentum must be conserved.
What happens with energy is secondary.
You can solve for $v_{1,f}$ in terms of $m_1$, $m_2$, $v_{1,i}$, $v_{2,i}$, and $v_{2,f}$...
and you are given values for everything.
If, it turns out, there are energy losses, then one can seek reasons** for that.
(If you weren't given enough information, then appealing to the assumption of an elastic collision can be considered.)
In all cases, total-momentum conservation is primary.
**reasons could include other forms of energy not already considered:
rotational kinetic energy? heat?
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http://math.stackexchange.com/questions/395059/a-problem-on-logic-statements
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A problem on logic statements
I have series of statement that can logically be true($1$) or false($0$). For example if I have just one statement i.e
1. Statement $1$ is false.
Statement $1$ says that itself is false which is contradictory, so I can conclude that the statement is, in conclusion, contradictory. But if I have $2$ statements such that
1. Statement $2$ is false
2. Statement $1$ is false
If statement $1$ is true, then statement $2$ must be false which implies that statement $1$ is true. If statement $2$ is true then statement $1$ must be false which in turn implies that statement $2$ is true. We see that there are no contradictions between these two statements.
But of course the two examples are simple cases. Assuming that I have the following $10$ statements (I can have more, but for example)
1. Statement $5$ is true.
2. Statement $7$ is false.
3. Statement $4$ is true.
4. Statement $5$ is false.
5. Statement $3$ is true.
6. Statement $7$ is false.
7. Statement $1$ is false.
8. Statement $8$ is true.
9. Statement $10$ is false.
10. Statement $1$ is false.
What procedures do I have to take to or simply how do I successfully determine the statements that correlate and those that contradicts?
-
You should try an ordered list (using numbers instead of - for the list items), it would ease up the reading. – Asaf Karagila May 17 '13 at 23:27
Let $a_1, a_2, \ldots, a_n$ be variables, each equal to $1$ (true) or $-1$ (false). Then your statements become equations.
If Statement $i$ says Statement $j$ is false, that means $a_i=-a_j$.
If Statement $i$ says Statement $j$ is true, that means $a_i=a_j$.
In your example, $a_1=a_5, a_2=-a_7, a_3=a_4, a_4=-a_5, a_5=a_3, \ldots$. Already you have a contradiction among $a_3, a_4, a_5$.
In general, if there is one solution, there will be at lesat two (everyone swaps true, false). So pick $a_1$ to be true, and trace along the equations. If $a_1$ is true, then $a_5$ is true, then $a_3$ is true, then $a_4$ is true, then $a_5$ is false (contradiction). If you got to a cycle without a contradiction, look at the unused equations. If any of them connect to what you've built so far, then continue; otherwise you have two disjoint components (e.g. $a_1=a_2, a_3=a_4=-a_5$).
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https://homework.cpm.org/category/CCI_CT/textbook/calc/chapter/3/lesson/3.2.2/problem/3-64
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### Home > CALC > Chapter 3 > Lesson 3.2.2 > Problem3-64
3-64.
Using the definition of the derivative as a limit, show that the derivative of $f ( x ) = \frac { 1 } { x ^ { 2 } }$ is$f ^ { \prime } ( x ) = - \frac { 2 } { x ^ { 3 } }$. That is, show algebraically that the following is true:
$\lim\limits_ { h \rightarrow 0 } \frac { \frac { 1 } { ( x + h ) ^ { 2 } } - \frac { 1 } { x ^ { 2 } } } { h } = - \frac { 2 } { x ^ { 3 } }$
This is one form of the 'definition of the derivative' (informally known as Hana's Method).
In order to evaluate this limit, we need to find an Algebraic way to cancel out the $h$ in the denominator.
Find a common denominator in the numerator, expand and combine like terms:
Factor the numerator, then cancel out the $h$:
Since there is no longer and $h$ in the denominator, you can evaluate the limit as $h → 0$:
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https://zbmath.org/?q=an:1295.35161
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×
# zbMATH — the first resource for mathematics
Continuous maximal regularity on uniformly regular Riemannian manifolds. (English) Zbl 1295.35161
Summary: We establish continuous maximal regularity results for parabolic differential operators acting on sections of tensor bundles on uniformly regular Riemannian manifolds $$\mathsf M$$. As an application, we show that solutions to the Yamabe flow on $$\mathsf M$$ instantaneously regularize and become real analytic in space and time. The regularity result is obtained by introducing a family of parameter-dependent diffeomorphisms acting on functions on $$\mathsf M$$ in conjunction with maximal regularity and the implicit function theorem.
##### MSC:
35B65 Smoothness and regularity of solutions to PDEs 35K55 Nonlinear parabolic equations 53C44 Geometric evolution equations (mean curvature flow, Ricci flow, etc.) (MSC2010) 53A30 Conformal differential geometry (MSC2010) 35K90 Abstract parabolic equations 35R01 PDEs on manifolds 58J35 Heat and other parabolic equation methods for PDEs on manifolds
Full Text:
##### References:
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This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.
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http://www.archive.org/stream/biologicalbullet129mari/biologicalbullet129mari_djvu.txt
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# Full text of "The Biological bulletin"
## See other formats
THE
BIOLOGICAL BULLETIN
THE MARINE BIOLOGICAL LABORATORY
Editorial Board
JOHN M. ANDERSON, Cornell University
JOHN B. BUCK, National Institutes of Health
LIBBIE H. HYMAN, American Museum of
Natural History
SHINYA INOUE, Dartmouth College
J. LOGAN IRVIN, University of North Carolina
L. H. KLEINHOLZ, Reed College
JOHN H. LOCHHEAD, University of Vermont
ROBERTS RUGH, Columbia University
WM. RANDOLPH TAYLOR, University of
Michigan
ANNA R. WHITING, Oak Ridge National
Laboratory
CARROLL M. WILLIAMS, Harvard University
DONALD P. COSTELLO, University of North Carolina
Managing Editor
VOLUME 129
JULY TO DECEMBER, 1965
Printed and Issued by
LANCASTER PRESS, inc.
PRINCE & LEMON STS.
LANCASTER, PA.
11
IHi BlOLOGK \i I' 1 LLETIN i> issued six times a \ear at llu
Lancaster Press. Inc.. 1 'rince and Lemon Streets. Lancaster, I'enn
sylvania.
Snb.scriptions and similar matter should be addressed to The
Biological I'.ulletin. Marine I !i( (logical Laboratory. Woods Ilole,
Massachusetts. Agent for (ireat liritain : \\'heldon and Wesley,
l.imiled. _'. .> and 4 Arthur Street. Xe\v Oxford Street, London,
\\ . C. -. Single nnmlier>. S.v75. Subscription per volume (three
issues . S'.00.
Coinmunii-ations relative to manuscripts should be sent to Dr.
Monald \\ C'ostello. Marine lliolog-ical Laboratory, Woods Hole,
Massachusetts, between June 1 and September 1, and to Dr.
Donald I 1 . Costello, P.O. Box 429, Chapel Hill, North Carolina.
during the remainder of the year.
Second-class postage paid at Lancaster, Pa.
LANCASTER PRESS, INC., LANCASTER, PA.
CONTENTS
No. 1. AUGUST, 1965
PAGE
Annual Report of the Marine Biological Laboratory 1
ARNOLD, JOHN M.
The inductive role of the yolk epithelium in the development of the squid,
Loligo pealii ( Lesueuer ) 72
BROWN, FRANK A., JR., AND YOUNG H. PARK
Phase-shifting a lunar rhythm in planarians by altering the horizontal mag-
netic vector 7"
DEAN, JOHN MARK, AND F. JOHN VERNBERG
Effects of temperature acclimation on some aspects of carbohydrate me-
tabolism in decapod Crustacea S7
FENG, S. Y.
Pinocytosis of proteins by ovster leucocvtes 95
GLYNN, PETER W.
Active movements and other aspects of the biology of Astichopus and
Leptosynapta (Holothuroidea ) 106
GOODBODY, I VAX
The biology of Ascidia nigra (Savigny). III. The annual pattern of
colonization 129
JONES, JACK COLVARD, AND RONALD E. WHEELER
Studies on spermathecal filling in Aedes aegypti (Linnaeus). I. Descrip-
tion ' 134
KOZLOFF, EUGENE N.
New species of acoel turbellarians from the Pacific Coast 151
LOHAVANIJAYA, PRASERT, AND EMERY F. SwAN
The separation of post-basicoronal areas from the basicoronal plates in the
interambulacra of the sand dollar, Echinarachnius parma ( Lamarck i . . . . 167
MENZEL, R. WINSTON, AND MARGARET Y. MENZEL
Chromosomes of two species of quahog clams and their hybrids 1S1
SAKAI, YOSHI T.
Studies on the ooplasmic segregation in the egg of the fish, Oryzias latipes.
III. Analysis of the movement of oil droplets during the process of ooplas-
mic segregation 1 S ( >
ZEIN-ELDIN, ZOULA P., AND DAVID V. ALDRICII
Growth and survival of postlarval Penaeus aztecus under controlled con-
ditions of temperature and salinity 199
No. 2. OCTOBKK, 1 l >(>5
BARNES, ROBERT D.
Tube-building and feeding in chaetoplerid polychartes 217
CARLSON, ALBERT D.
Factors affecting firefly larval luminescence 234
iv CONTENTS
G WILLIAM, G. F.
The mechanism of the shadow retle: in Cirripedia. II. Photoreceptor cell
response, second-order responses, and motor cell output 244
HALTOX, IX \\".. AND |. I',. JKXXI
Ohservations on tin- nutrition of monogenetic trematodes 257
HoRircm, SHIKO. \.\i> CHARLES I-'.. LANE
Digestive en/yines of the crystalline- style of Strombus gigas Linne. 1.
Cellulate and some other carbohydrases 273
JONES. JACK C'OLVAUD
The heniocUr- of Rhodnius prolixus Stal 282
KRIVAXKK. JKKOMK (X. AND l\oi;i.\ C. KRIYAXEK
Evidence for transaminase activity in the slime mold, Dictyostelium dis-
coideum Kaper 295
MENDO/A. GUILLERMO
The ovary and anal processes of "Characodon" eiseni, a viviparous cypri-
nodont teleost from Mexico 303
MrscAiixK. LEONARD, AXD HOWARD M. LENIIOFF
Symbiosis of hydra and algae. II. Effects of limited food and starvation
on growth of symbiotic and aposymbiotic hydra 316
I\ IK MANX. |oiix (I.
The development of eggs of the screw -worm fly Cochliomyia hominivorax
(Coquerel) (Diptera: Calliphoridae ) to the blastoderm stage as seen in
whole-mount preparations 329
SCHELTEMA. RUDOLF S.
The relationship of salinity to larval survival and development in Nas-
sarius obsoletus (Gastropoda) 340
SKINNER, DOROTHY M., DONALD J. MARSH AND JOHN S. COOK
Physiological salt solution for the land crab, Gecarcinus lateralis 355
STRAIX, I IAROLD H.
Chloroplast pigments and the classification of some siphonalean green algae
of Australia 366
S-rrxKARi), HORACE W., AXD FRED E. Lux
A microsporidian infection of the digestive tract of the winter flounder,
Pseudopleuronectes americanus 371
Ab>tracts of jiajx-rs jiresented at the Marine Biological Laboratory 388
\o. 3. DECEMBER, 1965
AIKU.O, EDWARD. AND GIAXCARLO GIMDERI
Distribution and function of the branchial nerve in the mussel 431
AKOV, SIIOSIIAXA
'ihibition of blood digestion and oocyte growth in Aedes aegypti by
5-fluorouracil 43 ( '
Ax. . JOHN MAXWKU.
011 visceral regeneration in sea .stars. 111. Regeneration of the
h in \stcrias forbesi I I )esor I 454
!'. \IMII. 1 . ( ,.
The nature oi he action of ions as inductors. 471
CONTENTS v
ECKSTEIN, B.. AND M. SPIRA
Effect of sex hormones on gonadal differentiation in a cichlid, Tilapia
aurea 482
Fox, SISTER ALICE MARIE
Effect of inhibitors on active transport by turtle intestinal segments 490
GUTKNECHT, JOHN
Ion distribution and transport in the red marine alga, Gracilaria foliifera 4^5
GRANT, WILLIAM C, JR., AND GEORGE COOPER. IV
Behavioral and integumentary changes associated with induced meta-
morphosis in Diemyctilus 510
HKXDRICKX, ANDREW G., AND ROBERT HANXLIK
Developmental stages of the bob-white quail embryo ( Colinus virginianus ) 523
JONES, JACK COLVARD, AND RONALD E. WHEELER
Studies on spermathecal Filling in Aedes aegypti (Linnaeus). II. Ex-
perimental 532
LOOSANOFF, VICTOR L.
Gonad development and discharge of spawn in oysters of Long Island
Sound 546
MlLLOTT. X., AND W. G. LYNN
Further studies on the effect of phenylthiourea on pigmentation by me-
lanin in amphibians 562
STEPHENS. GROVER C.. JOHN F. VAN PILSUM AND DORRIS TAYLOR
Phylogeny and the distribution of creatine in invertebrates 573
WEBB, H. MARGUERITE, AND FRANK A. BROWN, JR.
Interactions of diurnal and tidal rhythms in the fiddler crab. Uca pugnax 582
August, 1Q65
Vol. 129, No. 1
THE
ERRATA
Page 16 PHYSIOLOGY
II. INSTRUCTORS
delete WILLIAM F. HARRINGTON
H YEAR
Page 17- MARINE BOTANY 1
II. INSTRUCTORS 4
delete FRANK E. ROUND
6
Page 18 INVERTEBRATE ZOOLOGY
9
III. ASSISTANTS . .
delete W. BRUCE HUNTER lents 23
add STEPHEN C. BROWN, University of Michigan 35
35
Page 20- MARINE ECOLOGY . 37
III. LABORATORY ASSISTANTS 37
delete MARGARET C. LLOYD
delete BARRY M. HEATFIELD
add DONALD C. GORDON, University of Rhode Island
65
Page 34 The following Invertebrate Zoology students should carry the
asterisk indicating they also completed the Post-Course Research
Program, July 28-August 31 :
BENNETT, JUDITH ANN, Syracuse University
BOLENDER, ROBERT PAUL, Columbia University
HALL, BARBARA SUE, College of St. Mary of the Springs
HINE, CHARLES RISK, Lafayette College
HUNTER, WILLIAM BRUCE, University of California, Santa Barbara Avenue, New
LANGRETH, SUSAN GRANT, University of Chicago
NUTT, JOHN GORDON, JR., Rice University
RUNDLES, CHARLOTTE, Duke University :w York
WALTERS, DAVID ROYAL, Harvard University ^e of Medicine
WHISNANT, BETTY LYNN, Duke University
York 5, New
Vol. 129, No. 1 August, 1965
THE
BIOLOGICAL BULLETIN
THE MARINE BIOLOGICAL LABORATORY
SIXTY-SEVENTH REPORT, FOR THE YEAR 1964 -SEVENTY-SEVENTH YEAR
I. TRUSTEES AND EXECUTIVE COMMITTEE (AS OF AUGUST 14, 1964) 1
II. ACT OF INCORPORATION 4
III. BYLAWS OF THE CORPORATION 4
IV. REPORT OF THE DIRECTOR 6
1 . Memorials 9
2. The Staff 14
3. Investigators, Lalor, Lillie and Grass Fellows, and Students . . 23
4. Fellowships and Scholarships 35
5. Training Programs 35
6. Tabular View of Attendance, 1960-1964 37
7. Institutions Represented 37
8. Evening Lectures 39
9. Evening Seminars 40
10. Members of the Corporation 41
V. REPORT OF THE LIBRARIAN 64
VI. REPORT OF THE TREASURER . 65
I. TRUSTEES
GERARD SWOPE, TR., Chairman of the Board of Trustees, 570 Lexington Avenue, New
York 22, New York
ARTHUR K. PARPART, President of the Corporation, Princeton University
JAMES H. WICKERSHAM, Treasurer, 791 Park Avenue, New York 21, New York
PHILIP B. ARMSTRONG, Director, State University of New York, College of Medicine
at Syracuse
ALEXANDER T. DAIGNAULT, Assistant Treasurer, 7 Hanover Street, New York 5, New
York
GEORGE W. DE VILLAFRANCA, Clerk of the Corporation, Smith College
1
Copyright 1965, by the Marine Biological Laboratory
MARINE BIOLOGICAL LABORATORY
EMERITI
\\~ILLIAM R. AMBERSON, Marine Biological Laboratory
C. LALOR BURDICK, The Lalor Foundation
C. LLOYD CLAFF, Randolph, Massachusetts
W. C. CURTIS, 504 West Mount Avenue, Columbia, Missouri
PAUL S. GALTSOFF, Woods Hole, Massachusetts
E. B. HARVEY, Woods Hole, Massachusetts
M. H. JACOBS, University of Pennsylvania
CHARLES W. METZ, Woods Hole, Massachusetts
CHARLES PACKARD, Woods Hole, Massachusetts
A. C. REDFIELD, Woods Hole, Massachusetts
CARL C. SPEIDEL, Randolph-Macon Woman's College
A. H. STURTEVANT, California Institute of Technology
ALBERT SZENT-GYORGYI, Marine Biological Laboratory
TO SERVE UNTIL 1968
E. G. BUTLER, Princeton University
A. C. CLEMENT, Emory University
ARTHUR L. COLWIN, Queens College
DONALD P. COSTELLO, University of North Carolina
JAMES D. EBERT, Carnegie Institution of Washington
DOUGLAS A. MARSLAND, Marine Biological Laboratory
ROBERTS RUGH, Columbia University, College of Physicians and Surgeons
H. BURR STEINBACH, University of Chicago
TO SERVE UNTIL 1967
LESTER G. BARTH, Columbia University
JOHN B. BUCK, National Institutes of Health
AURIN M. CHASE, Princeton University
SEYMOUR S. COHEN, University of Pennsylvania, School of Medicine
TERU HAYASHI, Columbia University
LEWIS KLEIN HOLZ, Reed College
ALBERT I. LANSING, University of Pittsburgh
S. MERYL ROSE, Tulane University
TO SERVE UNTIL 1966
F. A. BROWN, JR., Northwestern University
F. D. CARLSON, The Johns Hopkins University
SEARS CROWELL, Indiana University
W. D. McELROY, The Johns Hopkins University
C. LADD PROSSER, University of Illinois
E. A. SCHARRER, Albert Einstein College of Medicine
SISTER FLORENCE MARIE SCOTT, Seton Hill College
WILLIAM RANDOLPH TAYLOR, University of Michigan
TO SERVE UNTIL 1965
ERIC G. BALL, Harvard Medical School
D. W. BRONK, The Rockefeller Institute
MAC V. EDDS, JR., Brown University
RUDOLF KEMPTON, Vassar College
I. M. KLOTZ, Northwestern University
ARNOLD LAZAROW, University of Minnesota Medical School
MORRIS ROCKSTEIN, University of Miami
GEORGE WALD, Harvard University
TRUSTEES
STANDING COMMITTEES
EXECUTIVE COMMITTEE OF THE BOARD OF TRUSTEES
ARTHUR K. PARPART, ex officio, Chairman H. BURR STEINBACH, 1967
GERARD SWOPE, JR., ex officio TERU HAYASHI, 1966
JAMES H. WICKERSHAM, ex officio WILLIAM D. MCELROY, 1966
PHILIP B. ARMSTRONG, ex officio ERIC G. BALL, 1965
E. G. BUTLER, 1967 SEARS CROWELL, 1965
THE LIBRARY COMMITTEE
KEITH PORTER, Chairman C. LADD PROSSER
ERIC G. BALL MORDECAI GABRIEL
JAMES LASH STANLEY WATSON
SEYMOUR S. COHEN
THE APPARATUS COMMITTEE
ALBERT I. LANSING, Chairman ARNOLD LAZAROW
CLIFFORD HARDING WILLIAM D. MCELROY
DAVID POTTER L. I. REBHUN
THE SUPPLY DEPARTMENT COMMITTEE
RUDOLF KEMPTON, Chairman SEARS CROWELL
HARRY GRUNDFEST FRANK M. FISHER
HOWARD A. SCHNEIDERMAN GEORGE SCOTT
THE INSTRUCTION COMMITTEE
TERU HAYASHI, Chairman MAIMON NASATIR
A. C. CLEMENT BOSTWICK KETCHUM
LEWIS KLEINHOLZ DE\VITT STETTEN
ROGER O. ECKERT
THE BUILDINGS AND GROUNDS COMMITTEE
EDGAR ZWILLING, Chairman J. WOODLAND HASTINGS
E. G. BUTLER J. W. GREEN
DANIEL GROSCH MELVIN SPIEGEL
MAC V. EDDS, JR.
P. M. FAILLA, Chairman H. BURR STEINBACH
S. J. COOPERSTEIN ROBERTS RUGH
DAVID SHEMIN GEORGE SZABO
PAUL R. GROSS
THE RESEARCH SPACE COMMITTEE
WILLIAM D. MCLROY, Chairman H. BURR STEINBACH
TERU HAYASHI EDGAR ZWILLING
THE COMMITTEE FOR NOMINATION OF OFFICERS
SEARS CROWELL, Chairman E. G. BUTLER
ERIC G. BALL TERU HAYASHI
WILLIAM D. MCLROY H. BURR STEINBACH
4 MARINE BIOLOGICAL I. AM( >K ATORY
II. ACT OF INCORPORATION
No. 31/0
COMMONWEALTH OF MASSACHUSETTS
Be It Known, That whereas Alpheus Hyatt, William Sanford Stevens, William T.
Sedgwick, Edward G. Gardiner, Susan Minns, Charles Sedgwick Minot, Samuel Wells,
William G. Farlow, Anna 1). Phillips, and B. H. Van Vleck have associated themselves
with the intention of forming a Corporation under the name of the Marine Biological
Laboratory, for the purpose of establishing and maintaining a laboratory or station for
scientific study and investigation, and a school for instruction in biology and natural his-
tory, and have complied with the provisions of the statutes of this Commonwealth in such
case made and provided, as appears from the certificate of the President, Treasurer, and
Trustees of said Corporation, duly approved by the Commissioner of Corporations, and
recorded in this office ;
Now, therefore, I, HENRY B. PIERCE, Secretary of the Commonwealth of Massachu-
setts, do hercb\ certify that said A. Hyatt, W. S. Stevens, W. T. Sedgwick, E. G. Gardi-
ner, S. Minns, C. S. Minot, S. Wells, W. G. Farlow, A. D. Phillips, and B. H. Van Vleck,
their associates and successors, are legally organized and established as, and are hereby
made, an existing Corporation, under the name of the MARINE BIOLOGICAL LAB-
ORATORY, with the powers, rights, and privileges, and subject to the limitations, duties,
and restrictions, which by law appertain thereto.
U' it ness my official signature hereunto subscribed, and the seal of the Commonwealth
of Massachusetts hereunto affixed, this twentieth day of March, in the year of our Lord
One Thousand Eight Hundred and Eighty-Eight.
[SEAL] HENRY B. PIERCE,
Secretary of the Commomvcalth.
III. BYLAWS OF THF CORPORATION OF THE MARINE
BIOLOGICAL LABORATORY
(Revised August 15, 1963)
I. The members of the Corporation shall consist of persons elected by the Board
of trustees.
II. The officers of the Corporation shall consist of a Chairman of the Board of
Trustees, President, Director, Treasurer and Clerk.
III. The Annual Meeting of the members shall be held on the Friday following the
second Tuesday in August in each year at the Laboratory in Woods Hole, Massachusetts,
at 9:30 A.M., and at such meeting the members shall choose by ballot a Treasurer and a
Clerk to serve one year, and eight Trustees to serve four years, and shall transact such
other business as may properly come before the meeting. Special meetings of the
members may be called by the Trustees to be held at such time and place as may be
designated.
IV. Twenty-five members shall constitute a quorum at any meeting.
Y. Any member in good standing may vote at any meeting, either in person or by
proxy duly executed.
VI. Inasmuch as the time and place of the Annual Meeting of members are fixed by
these bylaws, no notice of the Annual Meeting need be given. Notice of any special
meeting of members, howi-ver, shall be given by the Clerk by mailing notice of the time
and place and purpose of such meeting, at least fifteen (15) days before such meeting, to
each member at his or her address as shown on the records of the Corporation.
BYLAWS OF THE CORPORATION 5
VII. The Annual Meeting of the Trustees shall be held promptly after the Annual
Meeting of the Corporation at the Laboratory in Woods Hole, Massachusetts. Special
meetings of the Trustees shall be called by the Chairman, the President, or by any seven
Trustees, to be held at such time and place as may be designated, and the Secretary
shall give notice thereof by written or printed notice, mailed to each Trustee at his
address as shown on the records of the Corporation, at least one (1) week before the
meeting. At such special meeting only matters stated in the notice shall be considered.
Seven Trustees of those eligible to vote shall constitute a quorum for the transaction
VIII. There shall be three groups of Trustees :
(A) Thirty-two Trustees chosen by the Corporation, divided into four classes, each
to serve four years. After having served two consecutive terms of four years each,
Trustees are ineligible for re-election until a year has elapsed. In addition, there shall
be two groups of Trustees as follows :
(B) Trustees ex officio, who shall be the Chairman, the President, the Director, the
Treasurer, and the Clerk.
(C) Trustees Emeriti, who shall be elected from present or former Trustees by the
Corporation. Any regular Trustee who has attained the age of seventy years shall
continue to serve as Trustee until the next Annual Meeting of the Corporation, where-
upon his office as regular Trustee shall become vacant and be filled by election by the
Corporation and he shall become eligible for election as Trustee Emeritus for life. The
Trustees ex officio and Emeriti shall have all the rights of the Trustees, except that
Trustees Emeriti shall not have the right to vote.
The Trustees and officers shall hold their respective offices until their successors are
chosen and have qualified in their stead.
IX. The Trustees shall have the control and management of the affairs of the Cor-
poration. They shall elect a Chairman of the Board of Trustees who shall be elected
annually and shall serve until his successor is selected and qualified and who shall also
preside at meetings of the Corporation. They shall elect a President of the Corporation
who shall also be the Vice Chairman of the Board of Trustees and Vice Chairman of
meetings of the Corporation, and who shall be elected for a term of five years and shall
serve until his successor is selected and qualified, except that such term shall not run
beyond the Annual Meeting of the Board following his 65th birthday ; candidates over the
age of 65 shall be elected on an annual basis. They shall appoint a Director of the
Laboratory for a term not to exceed five years, provided the term shall not exceed
one year if the candidate has attained the age of 65 years prior to the date of the appoint-
ment. They may choose such other officers and agents as they may think best. They
may fix the compensation and define the duties of all the officers and agents ; and may
remove them, or any of them except those chosen by the members, at any time. They
may fill vacancies occurring in any manner in their own number or in any of the
offices. The Board of Trustees shall have the power to choose an Executive Committee
from their own number, and to delegate to such Committee such of their own powers
as they may deem expedient. They shall from time to time elect members to the
Corporation upon such terms and conditions as they may think best.
X. The Associates of the Marine Biological Laboratory shall be an unincorporated
group of persons (including associations and corporations) interested in the Laboratory
and shall be organized and operated under the general supervision and authority of
the Trustees.
XI. The consent of every Trustee shall be necessary to dissolution of the Marine
Biological Laboratory. In case of dissolution, the property shall be disposed of in such
manner and upon such terms as shall be determined by the affirmative vote of two-thirds
of the Board of Trustees.
o MAK1XK BIOLOGICAL LABORATORY
XII. The account of the Treasurer shall be audited annually by a certified public
accountant.
X I II. These bylaws may be altered at any meeting of the Trustees, provided that the
notice of such meeting shall state that an alteration of the bylaws will be acted upon.
RESOLUTIONS ADOPTED AT TRUSTEE MEETING AUGUST 16,
1963 K\ KCUTIVE COMMITTEE
I. RESOLVED:
(A) The Executive Committee is hereby designated to consist of ten members as
follows: e.v officio members who shall be the Chairman of the Board of Trustees,
President, Director and Treasurer; six additional Trustees, two of whom shall be
elected by the Board of Trustees each year, to serve for a three-year term.
(B) The President shall act as Chairman of the Executive Committee and the
Chairman of the Board of Trustees as Vice Chairman. A majority of the members
of the Executive Committee shall constitute a quorum and a majority of those present
at any properly held meeting shall determine its action. It shall meet at such times
and places and upon such notice and appoint such sub-committees as the Committee
shall determine.
(C) The Executive Committee shall have and may exercise all the powers of the
Board during the intervals between meetings of the Board of Trustees except those
powers specifically withheld from time to time by the Board or by Law.
(D) The Executive Committee shall keep appropriate minutes of its meetings, and
its actions shall be reported to the Board of Trustees.
II. RESOLVED:
The elected members of the Executive Committee shall be constituted as a standing
"Committee for the Nominations of Officers," responsible for making nominations at
the annual meeting of the Corporation and of the Board of Trustees, for candidates to
fill each office as the respective terms of office expire. (Chairman of the Board, Presi-
dent, Director, Treasurer, and Clerk.)
IV. REPORT OF THE DIRECTOR
To: Tin-. TRUSTEES OF THE MARINE BIOI.OCICAI. LABORATORY
Gentlemen :
I submit herewith the report of the seventy-seventh session of the Marine
Biological Laboratory.
1. Facilities Developments
During the past year a number of changes and developments in our facilities
were completed under a grant provided by the National Science Foundation. Over
the winter of 1963-64 the library stacks were repainted and fluorescent lighting
installed which brightened up the stacks most satisfactorily. The glass floors in
the stacks were overlaid with plywood, on top of which rubber tile was installed,
getting away from the hazard of breaking of the glass flooring and also giving a
REPORT OF THE DIRECTOR /
quiet walking surface. New quarters were provided for the library staff, directly
off the card catalogue room. The reading room has been extended to include the
area formerly occupied by the library staff, providing additional space for reference
A centralized instrument laboratory was provided by remodeling rooms 109
and 110 in the Lillie Building where large pieces of apparatus for the general use
of investigators and students can be supervised by a qualified technical assistant.
A suite of laboratories centrally located on the second floor of the Lillie Building
has been remodeled for electron microscopy. Included is a general service labora-
tory, facilities for two electron microscopists, and darkrooms for loading and devel-
oping film. These laboratories and instruments are under the supervision of an
expert electron microscopist.
Also, under the National Science Foundation Grant a new collecting boat, the
Ciona, was constructed, a 40-foot vessel powered by 180-hp. General Motors diesel
engine. This boat has proved to be exceptionally seaworthy and well adapted to
the Laboratory's service. The vessel was built by the Brownell Boatyard of Matta-
poisett, after a design by Eldredge-Mclnnis, naval architects.
The old Cayadetta dock, extending 140 feet out into Great Harbor in front of
the Laboratory, was rebuilt and was used daily throughout the summer by the
Cap'n Bill III, which unloaded its catch of bottom fish and squid directly into
mobile sea water tanks on the dock. These facilities provided by the National
Science Foundation Grant have contributed significantly to improved operations
in these areas. In addition the Laboratory made important modification of two
of the boats to better adapt them for biological collecting. The cruising speed of
the Limulus has been stepped up from 10 to 16 knots, extending her range. Also,
a new mast and boom, operating off of a motor driven winch, has improved the
operation significantly. Extensive modifications in the interior arrangements of
the Lhinihis and Dolphin have contributed to the ease, effectiveness, and safety in
the operation of these two boats.
2. Ford Foundation Grant
In 1963 the Planning Committee was instructed by the Executive Committee
to explore ways of funding its long-range plans which had previously been accepted
by the Executive Committee. This plan included additional housing for investi-
gators and students, new laboratory facilities for the courses and a laboratory-
equipped survey boat for the Systematics-Ecology Program. The needs of the
Laboratory were spelled out in detail and a request for a grant of $2,500,000 toward this program was made to The Ford Foundation. The plan envisions an instruc- tional building which will provide quarters for the regular courses and the Syste- matics-Ecology Program, a building of 65,000 square feet to be built at an estimated cost of$2,700,000. Also included in the program is a dining hall-dormitory to
replace the present dining hall and the old residences currently used to house stu-
dents. Included in the dormitory will be 125 double bedrooms. The estimated
cost of this facility is $1,700,000. Also in the grant request was$200,000 for addi-
tional cottages in the Devil's Lane tract and $100,000 for the Systematics-Ecology biological survey boat. S M \RL\l-; BIOLOGICAL LABORATORY \Ye were delighted to receive notification in June of a grant of$2,500,000 by
The Ford Foundation to the Laboratory. Of this, $300,000 is an outright grant in the amounts requested for additional cottages, particularly for younger investi- gators, and also funds for the Systematics-Ecology survey vessel. The remainder of the grant,$2,200,000. covers half the estimated cost of the instructional building
and the dining hall-dormitory, so matching funds must be obtained in a like amount.
A topographical survey of the free area of the Devil's Lane Tract was imme-
diately made, access roads laid out and construction of cottages promptly started.
Some additional funds were obtained from individual subscribers, so that 24 cot-
tages have been completed and will be ready for summer occupancy in 1965. The
contributors included Mrs. F. Newton Harvey, Mrs. Gary N. Calkins, Mrs. Samuel
O. Mast and The Gra.ss Foundation. Also, an extensive play area, readily accessi-
ble to both cottage colonies, has been laid out, providing recreation facilities for
children of all ages as well as adults.
Plans for the new Systematics-Ecology survey vessel have been completed and
construction will soon be started. This vessel will be 65 feet long, of steel con-
struction and equipped with the most modern equipment and gear for survey work.
Plans are being developed by the firm of Pierce, Pierce and Luykx for the
instruction building and the dining hall-dormitory. The instruction building will
be located on the north side of Center Street, east of the Apartment House. The
site for the dining hall-dormitory has not yet been selected. In the meantime the
Planning Committee is exploring various sources of additional funds to match the
grant from The Ford Foundation toward these two facilities.
3. Ricliard K. Mellon Foundation Grout
The Laboratory \vas most fortunate in receiving a grant of 50,000 from the Richard K. Mellon Foundation, toward the cost of construction of the instruction building. "\Ye were very much gratified by this support from one of our Woods Hole neighbors. 4. Rand Bequest The Laboratory was the beneficiary of a bequest this past year by the will of Mrs. Herbert \Y. Rand, in memory of her husband. Professor Herbert W. Rand, of Harvard University. Professor Rand first came to the Marine Biological Lab- oratory in 1923, and became a member of the Corporation in 1928. He resided in Falmouth after his retirement at Harvard in 1942 until his death. 5. Personnel Deborah Lawrence Harlow was a member of the Library staff at the Marine I'.iological Laboratory for 40 years, retiring at the end of 1964. She joined the staff in 1925 as secretary to the Librarian. Mrs. Harlow became thoroughly acquainted with the operation of the Library over a period of years and succeeded Mrs. Montgomery as Librarian in 1948. During her tenure as Librarian, the number of journals to which the Laboratory subscribed increased from 1200 to 1717, the number of volumes in the Library from 56,000 to well over 100,000. Although these are striking increases in numbers, Mrs. Harlow will always be re- REPORT OF THE DIRECTOR 9 membered for her very effective management of the Library, for her cooperative- ness and for the relaxed manner in which she furthered the library work of the scientists and students at the Laboratory. Mr. Harlow, for 17 years head of the machine shop, and expert in his field, retired at the same time. 1. MEMORIALS WINTHROP JOHN VANLEUVEN OSTERHOUT By THEODORE SHEDLOVSKY On August 2. 1871. Winthrop John Vanleuven Osterhout was born in Brooklyn, New York, the son of a Baptist minister whose ancestors came to America in the seventeenth century from the town of Osterhout in Holland. On April 9th of this year, Dr. Osterhout died in New York in his ninety-third year. In accordance with his wishes his ashes are buried in the cemetery of the Church of St. James the Less in Philadelphia, among four descendants of Benjamin Franklin, an ancestor of his widow, Marian Invin Osterhout. Many of us who knew him personally, and the Marine Bio- logical Laboratory, where he spent well over half the summers of bis long life, mourn his death. It seems to mark the passing of an important period in the history of bio- logical science, a period which bridged the nineteenth and twentieth centuries. At Woods Hole, as elsewhere, quantitative experimentation and important new ideas were supple- menting or displacing the traditional descriptive methods of research in biology. Here, at the Marine Biological Laboratory, a number of dedicated biologists, who were already eminent or were soon to become so, carried on their researches during the summer and influenced students an enterprise which is happily continuing. Among these dedicated biologists we find the names of Jacques Loeb, T. H. Morgan, Frank and Ralph Lillie, E. B. Wilson, E. G. Conklin, Walter Carrey, A. P. Mathews, Ivey Lewis, and, of course, W. J. V. Osterhout. Let us examine briefly his history as a man of science. While still an undergraduate student at Brown University, in 1892 young Osterhout came to the Marine Biological Laboratory, where W. A. Setchell introduced him to research in botany. He started work and soon found that the four spores in a red alga, Aquardhiclla tenero, each of which could produce a new plant, were able to combine and form a single plant. A year later, Osterhout had received the A.B. degree from Brown (I believe he was the class poet) and was again at Woods Hole, but now as Setchell's assistant in the Botany Course. Together, while collecting in Nobska Pond, they found Xitclla, but physiological experiments on this interesting material came only consider- ably later. After a year in Bonn, Germany, with the eminent plant cytologist, Eduard Stras- burger (1895-6) Setchell brought Osterhout to the University of California where he earned the Ph.D. degree in 1899 and met Jacques Loeb in 1902. Learning of Loeb's work on animal cells he began to make similar studies on plant cells and did so with considerable success. Among other things, he was much interested in Loeb's observa- tions on ionic antagonism, such as exists between monovalent and divalent or trivalent cations, and he used effectively the measurement of electrical conductance in such experi- ments with plant cells. Acquaintance with Loeb soon ripened into a great, life-long friendship. While still in California, Osterhout got to know Hugo de Vries and Svante Arrhenius. There, in those early years of the century, he doubtless participated in many discussions of matters scientific, philosophic, as well as honestly convivial. In 1909, Osterhout left the University of California as Associate Professor and moved to Harvard as Assistant Professor, to become Professor in 1913. When Loeb, 10 M. \RI.\K BIOLOGICAL LABORATORY who was a member of The Rockefeller Institute for Medical Research, died in 1924, Dr. Osterhout was invited by the Director, Dr. Flexner, to accept membership in the Institute. This invitation he accepted. At the Institute he was given a substantial department of general physiology and a small laboratory in Bermuda for work on Falonia and Halicystis. In -\Y\v York he was joiiu-d by Drs. Marian Irwin, Lawrence Blinks, and, a little later, by S. E. Hill, W. Stanley and several others. Interested, as he always was, in a physico-chemical approach to biological problems he arranged for D. A. Mac- Innes to form a physical-chemical group, affiliated with his department. L. G. Longs- worth and I soon joined that group. After his return east from California, and while he was still at Harvard, Osterhout again became intimately associated with the Marine Biological Laboratory and remained so until just a few years ago. He had been a Trustee since 1910. Those of us who had the privilege of knowing him here at Woods Hole, in Cambridge, or in New York, will fondly recall scientific discussions with him, which often took the form of Socratic dialogues, general conversations which were seldom trivial and were usually well sea- soned with wit and wisdom. We remember him as a gentleman, in the best and most accurate sense of the word, always with dignity but never with pomp or without a subtle warmth. We shall miss him; not only the scientist, botanist, physiologist, but also the mentor, the councillor, the friend. I speak not only for myself but also, I am certain, for many others. Osterhout was a superb teacher. Although I did not have the good fortune of being one of his students at Harvard, I know that his influence in attracting young people to research in biology was great. He had a gift for devising beautiful experimental demon- strations which were presented with a persuasive but dignified enthusiasm for the subject that inspired many of his graduate students to undertake productive careers in research. \\hat were his main contributions to science? Here in the Marine Biological Lab- oratory Library, there are about 270 cards in the W. J. V. Osterhout file. These in- clude references to his early work in cytology, salt antagonism, osmotic studies and other physico-chemical aspects of plant cells and plant cell models. Perhaps his principal work was on permeability aspects and electrical properties of single plant cells. He was very early in accounting for the active transport of ions by a molecular carrier mecha- nism. To show this he constructed cell models which exhibited active transport with carrier molecules passing through non-aqueous membranes. For example, aqueous tri- choloracetic acid and pure water, separated by a layer of guaiacol in the bottom of a U-tube, showed the water apparently moving against its chemical potential gradient. Water movement and water absorption interested him greatly and formed one of the subjects of his work with Mrs. Osterhout into the evening of his scientific life. IVginning with his early experiments in California on the relation of electrical conductivity of plant cells and ionic antagonisms, the bio-electric phenomena in living cells had always held his active interest. This traditionally controversial field has been so from the time of Volta and Galvani, through the period of phase boundary potentials 'crsiis diffusion potentials, and even remains so today in the present era of biochemical and biophysical euphoria. Such a field is not an easy one to explore, but as Osterhout said of Loeb, "He did not select problems because they were easy, but because of their importance. His courage sprung largely from his faith in the materialistic concep- tion. . . ." While at Harvard, his extensive electrical studies on Lcnninuria led in 1922 to the book, "injury, Recovery and Death in Relation to Conductivity and Permeability" This book stimulated other investigators by its novelty of concept and method of interpretation involving consecutive reactions. Throughout his life, Osterhout stimulated biologists to engage in meaningful quantitative experiments, and physical chemists and physicists to consider the problems presented by the living cell. REPORT OF THE DIRECTOR H Questions of photosynthesis, respiration, oxidation and related topics had received attention in his publications. In particular, mention may be made of his demonstration of photo induction through a striking observation with A. R. Haas (1918) in which lie noted that when the marine plant, Viva, was transferred from darkness to light the rate of photosynthesis was increased. I have already mentioned the important concept of carrier molecules, so much invoked today. It should also be noted that Osterhout pioneered in the concept of the steady- state as against equilibrium in accounting for the kinetics of penetration of substances into living cells, and, of course, no self-respecting student of molecular biology today will deny at least some knowledge of irreversible thermodynamics. But Osterhout's influence in general physiology was even greater than the sum of his papers and of his personal contacts with other investigators and students. I refer to the Journal of Gen- eral Physiology. He was, with Jacques Loeb, co-editor of this journal from its begin- ning. Let me quote from his own words in the "Outline of the History of the Journal of General Physiology," written in 1955 : "Dr. Jacques Loeb and I realized the need for a journal to promote the study of general physiology. Dr. Flexner agreed to publish the Journal from The Rockefeller Institute for Medical Research beginning in 1918. Dr. Loeb and I were the sole editors until he died in 1924. The statement, 'Founded by Jacques Loeb' was placed on the cover of the Journal and a memorial volume was pub- lished in his honor. Dr. John H. Northrop and Dr. William J. Crozier joined the editorial board in 1924 after Loeb's death. For about twenty-two years Dr. Northrop, Dr. Crozier and I were the only editors. In 1946 Dr. Wallace O. Fenn joined us. For about thirty-seven years each editor read every paper submitted." We shall miss Dr. Osterhout. But, for many of us, memory will often be refreshed when we see the Journal of General Physiology, when we visit the Marine Biological Laboratory, when we think of Nitella, Valonia, Halicystis, Laminaria, or when we recall the wit and wisdom which so often emanated from him to inspire us in so many ways. ELIOT R. CLARK By SEARS CROWELL Dr. Eliot R. Clark was born November 13, 1881, in Shelburne, Massachusetts. He received his A.B. degree from Yale University in 1903, and the M.D. degree from The Johns Hopkins University Medical School in 1907. He was on the staff of the Depart- ment of Anatomy at The Johns Hopkins University and carried on postdoctoral studies at the Universities of Munich and Krakow. From 1914 to 1922 he was a professor at the University of Missouri, and from 1922 to 1926 at the University of Georgia. In 1926 he became Head of the Department of Anatomy at the University of Pennsylvania, a post which he held until 1947. He became Professor Emeritus in 1950 and a guest investigator at the Wistar Institute. He received an honorary Sc.D. from Washington and Jefferson College in 1940. During the past seven years a serious heart condition prevented much physical activity but he retained an alert mind and lively interest in the affairs of Woods Hole. His death came instantly on November 1, 1963 in his home in Philadelphia. His association with the Marine Biological Laboratory began in 1909 when he became a member of the Corporation and also met Eleanor Linton, who was to become his wife two years later. He served as a Trustee of the Laboratory from 1930 to 1946. Mrs. Clark's father was Dr. Edwin Linton, a distinguished parasitologist, who worked at the Bureau of Fisheries. Dr. and Mrs. Linton devoted much time and attention to the Marine Biological Laboratory Club and the Clarks carried on this tradition. Dr. Clark served as Secretary-Treasurer in 1918 and 1919, and later as President. Both of 12 MARINE BIOLOGICAL I. \I5OKATOKV the Clarks were active in various fund-raising affairs for the Marine Biological Lab- oratory Club and Tennis Club. In the Wood> I loir community tin- (.'larks were involved with the choral group and in support of the Penzance 1 'layers. Later, as their children became sailing enthu- siasts, the Clarks contributed much to the Woods Hole Yacht Club. Dr. Clark was acting Commodore during World War II, and Commodore from 1947 to 1950. Apart from his connections with Woods Hole, Dr. Clark was most active profes- sionally in the American Association of Anatomists, serving as their Secretary-Treasurer for the periods of 1938-1942 and 1943-1946. He was largely instrumental in building up the excellent collection of research motion pictures, now housed in the Wistar Insti- tute, lie served for many years as Chairman of the Committee on Motion Pictures of the American Association of Anatomists. He reviewed films submitted by investigators and wrote brief descriptions of each accepted. He compiled the lists of these for pub- lication in the Anatomical Record. The majority of Eliot Clark's papers, many of them with Mrs. Clark as co-author, deal with problems of the circulatory system. Although he regarded himself as an anatomist, much of his work is developmental and physiological. By about 1930 he and his associates had perfected the technique of implanting windows in the ears of rabbits. With this technique he was able to study microscopically the development of blood vessels, lymphatics, nerves, epidermis, and various implanted tissues. Older workers at the Marine Biological Laboratory will recall with pleasure the demonstra- tions presented by the Clarks at the scientific meetings of the Laboratory. Dr. Clark's careful attention to detail, thoroughness, and devotion characterized both his scientific work and his services to the scientific community, the Marine Biological Laboratory, and Woods Hole. FRANK PATTENGILL KNOWLTON By WALTER S. ROOT Frank P(attengill) Knowlton, the son of Charles Fox and Mary (Pattengill) Knowl- ton, was born in Hollard Patent, New York, on June 17, 1875. He received the A.B. degree from Hamilton College in 1896 and the M.A. degree from the University of Michigan in 1897. FVom 1897-1900 he was an Instructor in Physiology and Embryol- ogy at the College of Medicine, Syracuse University. During this period he also studied medicine, receiving the M.D. degree in 1900. He served successively at Syra- cuse as Lecturer in Physiology, 1900-1906; Associate Professor, 1906-1908; Professor 1908-1946; and Emeritus Professor of Physiology since 1946. As student and teacher he spent 49 years at Syracuse. I remember his remarking one day as he surveyed a new class that teaching the sons of former students can be taken in one's stride, but that when the grandsons appear, one feels older. Dr. Knowlton spent the years of 1911-1912 at Cambridge University and at Uni- versity College, London. The studies carried out at this time were concerned with the relation of colloids to diuresis, the effects of stimulating the 8th and 9th spinal nerve roots upon the toad bladder, the sugar consumption of the isolated mammalian heart, the sugar consumption of the normal and diabetic heart, and the nature of pancreatic diabetes. They were published in four papers in the Journal of Physiology, one in the Proceedings of the Royal Society and one in the Zcitsclirijt fiir Physiologic. Of this work, perhaps the most important was the development and use of the heart-lung prep- aration in collaboration with the great physiologist, Ernest II. Starling. Knowlton was fortunate in having the opportunity of working in England at a time when an impressive group of men were active. Among these may be mentioned F. Gowland Hopkins, John Scott Ilaldane, Charles Sherrington, Joseph Barcroft, John Newport Langley, T. R. REPORT OF THE DIRECTOR 13 Elliott, William Bayliss, Walter Fletcher, E. A. Sharpey-Schafer, James Mackenzie, Henry Head, Thomas Lewis and others. Knowlton maintained a continuing interest in renal physiology, carbohydrate metabo- lism and diabetes mcllitus. In the latter part of his professional life he was active in studying the physiology of inhibition. The published papers on this subject are con- cerned with reciprocal inhibition in the earthworm, peripheral inhibition in arthropods, peripheral neuromuscular augmentation in the heart of Limulus polyphemus, inhibition in the cardiac ganglia of Limulus, the dual control of crustacean muscle, and inhibition of the turtle heart, and of turtle atria. Many of the publications in the field of comparative physiology were carried out in the Marine Biological Laboratory of which he was a Trustee from 1932 to 1946, and a Trustee Emeritus since 1946. As in his English experience, Knowlton was active in Woods Hole at a time when the Laboratory housed many distinguished scientists. In 1902 Dr. Knowlton married Clara Avis Roberts. It was a congenial partnership, and their home was always a pleasant place to visit. They had one child, a daughter, Catherine Morilla (now Mrs. Lucius Foote), who like her father is a medical graduate of Syracuse. A grandson, Knowlton Foote, is currently a graduate student in Bio- chemistry at the Syracuse Medical Center. Dr. Knowlton was a member of the Physiological Society of Great Britain, and the American Physiological Society, the annual meeting of which he attended regularly. He was active in the Western New York Section of the Society for Experimental Biology and Medicine for many years. He was also a member of a number of social and honorary societies (Delta Upsilon, Nu Sigma Nu, Sigma Xi, Alpha Omega Alpha, Phi Kappa Phi). Dr. Knowlton was a modest man. He was always a kind and considerate companion. A mutual friend wrote to me recently that he had died on October 30, 1963, without pain or suffering. I liked the statement that his end was much as his life had been, peaceful and orderly. IVEY FOREMAN LEWIS By CARL C. SPEIDEL Ivey Foreman Lewis was born on August 31, 1882, in Raleigh, North Carolina. Eighty-one years later he died in Charlottesville, Virginia, on March 16, 1964, after having been associated with the University of Virginia for nearly 50 years. He is survived by a son, Ivey Foreman Lewis, Jr., of Hampton, and a daughter, Margaret Elliott Lewis of Charlottesville. Ivey Lewis graduated from the LTniversity of North Carolina, receiving the degrees of A.B. in 1902 and M.S. in 1903. He was awarded the Ph.D. degree by The Johns Hopkins University in 1908. For his published dissertation, entitled "The Life History of GriffitJisia bornetiana" he was given the Walker Prize by the Boston Society of Natural History. He studied abroad in 1908 at the University of Bonn and at the Naples Zoological Station. During the academic year 1905-1906 and again after returning from Naples, he was Professor of Biology at Randolph-Macon College at Ashland, Virginia. During this period he made the acquaintance of Margaret Hunter, of Ashland, who became his wife in 1909. Three years later he left Randolph-Macon College to be Assistant Professor of Botany at the University of Wisconsin. In 1914 he was made Professor of Botany at the University of Missouri. The following year he was ap- pointed Miller Professor of Biology and Agriculture at the University of Virginia, where he served as Professor, and also as Dean from 1934 on, until his retirement in 1953. For many years Dr. Lewis was associated with the Woods Hole Marine Biological Laboratory. He was an Instructor in Botany in 1907 and again from 1910 through 14 MARINE BIOLOGICAL LABORATORY 1917. From 1918 through 1927 he was in charge of botanical instruction, and also served as Trustee and member of the Executive Committee. In 1928 he was a Carnegie Fellow at the Dry Tortugas Laboratory and in 1929 a Professor at the Hopkins Marine Station of Stanford University. From 1933 until 1946 he was Director of the Uni- versity of Virginia's newly established summer station at Mountain Lake, Virginia. Dr. Lewis founded the Association of Virginia Biologists in 1920. This gave rise to the Virginia Academy of Science in 1923. The following year he was elected its first President. For eight years he was a member of the Division of Biology and Agri- culture of the National Research Council and served as Chairman from 1933 through 1936. He was President of the American Society of Naturalists (1939), President of the American Biological Society (1942), and President of the Botanical Society of America (1949). In 1947 he received an honorary degree of Doctor of Science from the University of North Carolina. In 1959, six years after his retirement from active duty, he was the recipient of the University of Virginia's Thomas Jefferson Award. Dr. Lewis's research interests were primarily in the field of algology. In addition to his prize-winning doctorate thesis cited above, his publications include papers dealing with the algae of the Woods Hole and Charlottesville regions, the vegetation of Shackle- ford Bank, North Carolina, and the pollen of the Dismal Swamp of Virginia and North Carolina. One of his papers, entitled "The Flora of Penikese, Fifty Years After," published in Rhodora in 1924, is of historic interest to the Marine Biological Laboratory. This is a survey similar to one made in 1873 by David Starr Jordan, a member of Agassiz's Laboratory which was located on Penikese Island. Jordan's results were published in the American Naturalist in 1874. Dr. Lewis served as editor of the 1924 survey which was made cooperatively by the students and staff of the course in Botany at the Marine Biological Laboratory. Agassiz's Laboratory on Penikese is regarded as a kind of fore- runner of the Woods Hole Marine Biological Laboratory. For recreation Dr. Lewis greatly enjoyed the numerous collecting trips made as a part of the course in Botany. He also enjoyed the game of tennis and was an enthu- siastic and proficient player. His figure was a familiar one on the Mess Hall court. He always regretted that his duties in connection with the Mountain Lake Station in Virginia made it necessary for him to terminate his regular summer attendance at Woods Hole. Ivey Lewis's influence on the Marine Biological Laboratory was a beneficent one. In the most literal sense of the expression, he was a gentleman and a scholar. Those of us who knew him well miss him greatly. 2. THE STAFF EMBRYOLOGY I. INSTRUCTORS JAMES D. EBERT, Director, Department of Embryology, Carnegie Institution of Wash- ington, in charge of course DONALD D. BROWN, Staff Member, Department of Embryology, Carnegie Institution of Washington ALLISON L. BURNETT, Associate Professor of Biology, Western Reserve University ROBERT L. DE HAAN, Staff Member, Department of Embryology, Carnegie Institution of Washington THOMAS J. KING, Head, Department of Embryology, Institute for Cancer Research, Philadelphia REPORT OF THE DIRECTOR 15 JAMES W. LASH, Assistant Professor of Anatomy, University of Pennsylvania AARON A. MOSCONA, Professor of Zoology, University of Chicago II. LABORATORY ASSISTANTS C. B. KIMMEL, The Johns Hopkins University DAVID E. KOHNE, Purdue University J. D. EBERT T. J. KING T. J. KING R. L. DE HAAN A. J. COULOMBRE E. ZWILLING S. SIMPSON J. LASH A. MOSCONA A. MOSCONA A. MOSCONA H. RUBIN M. ROSENBERG P. MARCUS A. L. COLWIN M. STEINBERG A. BURNETT A. BURNETT A. BURNETT J. D. EBERT J. W. LASH J. W. LASH K. R. PORTER K. R. PORTER E. HADORN T. GALL T. J. KING R. L. DE HAAN E. HADORN D. D. BROWN P. GROSS E. BELL T. R. COLLIER I. DAVID A. MONROY III. LECTURES Perspectives in developmental biology Teleosts I Teleosts II Cell movements and morphogenesis The morphogenetic interaction of the tissues of the eye during development Morphotypic diversity vs. histiotypic identity Tissue interactions and morphogenesis in lizard tail re- generations The induction of chondrogenesis in vitro Sponges I Sponges II Tissue reconstruction from dissociated cells The malignant transformation of animal cells by viruses Some applications of surface physics to cell biology Dynamics of plasma membrane modification in virus-in- fected and normal cells Role of the gamete membranes in fertilization Adhesive selectivity in intercellular reactions A model of growth for hydroids and tubules of higher organisms The role of neoblasts in the maintenance of form of hydroids Dedifferentiation and redifferentiation of somatic cells in Hydra an analysis of polymorphism Developmental aspects of immunity Ascidians I : General embryology Ascidians II: Metamorphosis Developmental cytology I Developmental cytology II Developmental aspects of pleiotropic effects of genes The nucleic acids of giant chromosomes The developmental capacity of nuclei transplanted from advanced embryos Comparative morphogenesis of annelids, molluscs and echinoderms Problems of differentiation and pattern formation in Dro- sophila blastemas Biochemistry of oogenesis and early development Microsymposium : biochemistry of early development 16 MARINE BIOLOGICAL LABORATORY A. B. PARDKE Cell regulatory mechanisms I A. B. PARDEE Cell regulatory mechanisms II S. COHEN An epidermal growth-stimulating protein M. SINGER The nervous control of the regeneration of body parts in vertebrates V. HAMBURGER Xeurogenesis and the embryology of behavior K. MEYER Keratosulfates of cornea and cartilage G. W. COOPER Induction of somite chondrogenesis by cartilage and noto- chord : a correlation between inductive activity and cytodifferentiation H. SCHNEIDERMAN The hormonal control of insect development L. \\~EISS The structure of lymphatic tissue and its reaction in runt disease PHYSIOLOGY I. CONSULTANTS MERKEL H. JACOBS, Professor of Physiology, University of Pennsylvania ARTHUR K. PARPART, Professor of Biology, Princeton University ALBERT SZENT-GYORGYI, Director, Institute for Muscle Research, Marine Biological Laboratory W. D. MCELROY, Director, McCollum-Pratt Institute, The Johns Hopkins University II. INSTRUCTORS J. WOODLAND HASTINGS, Professor of Biochemistry, University of Illinois, in charge of course E. A. ADELBERG, Professor of Microbiology, Yale University HARLYN HALVORSON, Professor of Bacteriology, University of Wisconsin SHINYA INOUE, Professor of Cytology, Dartmouth College K. E. VAN HOLDE, Professor of Physical Chemistry, University of Illinois FRED KARUSH, Professor of Microbiology, University of Pennsylvania WILLIAM F. HARRINGTON, Professor of Biology, The Johns Hopkins University HANS KORNBERG, Professor of Biochemistry, Leicester University, England III. LABORATORY ASSISTANTS GEORGE KISSIL, University of Wisconsin CAROLYN EBERHARD, University of California at Berkeley IV. LECTURES SKYMOUR COHKN The lethality of streptomycin and the stimulation of RNA synthesis A. J. Soi'ii IAXOPOULOS Protein denuturution and hydrogen-ion equilibria of lyso- zyme HOWARD SCIIACHMAN Macromolecular configurations GEORCI; WALD Human color vision R. K. CLAYTON Photosynthesis II : Physical aspects ROGER ECKKKT Excitation-response coupling: Bioelectric flash triggering in Noctiluca WILLIAM HAGTNS Early steps in the excitation of photoreceptors REPORT OF THE DIRECTOR 17 The bacterial endospore and the problem of biological dormancy Fine structure of muscle Studies on ciliary movement Studies on the spectral complexes between flavo-proteins and their competitive inhibitors Mechanism of hormone action Growth Microbial metabolism I Microbial metabolism II Microbial metabolism III Immunochemistry I. The interactions of immunoglobulins Immunochemistry II. The nature of immunoglobulins Immunochemistry III. The biosynthesis of immunoglobulins Applications of immunochemistry to problems in biology Phosphorescence properties of DNA complexes Synthesis and stability of messenger RNA Photosynthesis I : Biochemical aspects Transcription and translation of the bacterial chromosome Replication and transfer of bacterial DNA Some aspects of regulation of gene function Polarization microscopy : An approach to fine-structure analysis in living cells Dynamic aspects of the mitotic apparatus Molecular arrangement of DNA in the living sperm Microbial metabolism Protein structure III. Multichain proteins Protein biosynthesis I : In vivo Protein biosynthesis II : In vitro The control and timing of enzyme synthesis The bacterial chromosome : Structure and function The bacterial chromosome: Replication Enzymatic intermediates in the bacterial bioluminescent reaction Crystalline bioluminescent particles : The Gonyaulax sys- tem Some aspects of the mechanism of enzyme action Protein Structure I : Physical methods of investigation Protein Structure II : The folding of polypeptide chains MARINE BOTANY I. CONSULTANTS WILLIAM RANDOLPH TAYLOR, Professor of Botany, University of Michigan RICHARD C. STARR, Professor of Botany, Indiana University II. INSTRUCTORS WALTER R. HERNDON, Professor of Botany, University of Tennessee, in charge of course PHILIP W. COOK, Department of Botany, University of Vermont H. WAYNE NICHOLS, Assistant Professor of Botany, Washington University FRANK E. ROUND, Department of Botany, University of Bristol, England ROBERT T. WILCE, Assistant Professor of Botany, University of Massachusetts ALEX KEYNAN H. E. HUXLEY IAN GIBBONS C. VEEGAR RACHMIEL LEVINE ALBERT SZENT-GYORGYI HANS LEO KORNBERG HANS LEO KORNBERG HANS LEO KORNBERG FRED KARUSH FRED KARUSH FRED KARUSH LAWRENCE LEVINE IRVIN ISENBERG CYRUS LEVINTHAL R. K. CLAYTON E. A. ADELBERG E. A. ADELBERG K. C. ATWOOD S. INOUE S. INOUE S. INOUE HANS LEO KORNBERG K. E. VAN HOLDE HARLYN HALVORSON HARLYN HALVORSON HARLYN HALVORSON E. A. ADELBERG E. A. ADELBERG J. W. HASTINGS J. W. HASTINGS WILLIAM P. JENCKS K. E. VAN HOLDE K. E. VAN HOLDE 18 MAKIXI-: UlOLOr.lCAL LABORATORY III. LABORATORY ASSISTANTS RUSSELL G. RHODES, Department of Botany, University of Tennessee ERNEST NEAL, Department of Botany, University of Tennessee IV. COLLECTOR MARTHA HODGE, l'ni\er>ity of Michigan INVERTEBRATE ZOOLOGY I. CONSULTANTS I'. A. MROWN. JR., Morrison Professor of Biology, Northwestern University I.IBBIE H. IIv.MAN, American Museum of Natural History CLARK P. READ, Professor of Biology, Rice University ALFRED C. REDFIELD, Woods Hole Oceanographic Institution II. INSTRUCTORS \Y. D. RUSSELL HUNTER, Professor of Zoology, Syracuse University, in charge of course GEORGE HOLZ, Professor of Microbiology, State University of New York, Upstate Medi- cal Center ROGER MILKMAN, Associate Professor of Zoology, Syracuse University IRWIN W. SHERMAN, Assistant Professor of Biology, University of California at River- side ALLAHVERDI FARM AN FARM AIAN, Professor of General Physiology, Pahlavi University, Shiraz, Iran ERIC L. MILLS, Assistant Professor of Biology, Queen's University, Kingston, Ontario, Canada FRANK M. FISHER, Assistant Professor of Biology, Rice University SEARS CROWELL, Professor of Zoology, Indiana University III. ASSISTANTS JOHN H. BUSSER, University of Rhode Island \Y. I'.RUCE HUNTER, University of California at Santa Barbara IV. LECTURES ROU.K D. MILKMAN 1'rotochordata II JOHN J. LEE The study of living Foraminifera in the laboratory GEORGE HOLZ The nature of the Protozoa GEORGE HOLZ Mastigophora GEORGE HOLZ Rhizopodea and Actinopodea <". IORGE HOLZ Foraminifera 'ii'iRGE HOLZ Ciliophora I\. A. BOOLOOTIAN, Dialogue on aspects of ediinoderm physiology A. FARMAXFARMAIAN W. D. R. HUNTER An approach to zooplankton A. FARMANFARMAIAN The echinoderms I Introduction: C'rinoidea and Asteroidra REPORT OF THE DIRECTOR 10 IRWIN W. SHERMAN A. FARMANFARMAIAN A. FARMANFARMAIAN ROGER D. MILKMAN ERIC L. MILLS W. D. RUSSELL HUNTER ERIC L. MILLS ERIC L. MILLS LUIGI PROVASOLI ROBERT HESSLER ERIC L. MILLS FRANK FISHER FRANK FISHER W. D. RUSSELL HUNTER CLARK P. READ IRWIN W. SHERMAN IRWIN W. SHERMAN IRWIN W. SHERMAN ERIC L. MILLS ROGER D. MILKMAN FRANK FISHER FRANK FISHER W. D. RUSSELL HUNTER W. D. RUSSELL HUNTER W. D. RUSSELL HUNTER SEARS CROWELL SEARS CROWELL SEARS CROWELL SEARS CROWELL ROGER D. MILKMAN Physiological studies on malarial parasites The echinoderms II : Holothuroidea The echinoderms III : Echinoidea and Ophiuroidea Protochordata I Arthropoda II : Larvae, lines and limbs further introduc- tion to the Crustacea Molluscs leave the sea (physiological variation and evo- lution) Arthropoda III : Feeding in Crustacea Cephalocarida, Branchiopoda, and Mystacocarida Arthropoda IV: Feeding in Crustacea Copepoda, Cirri- pedia, and Malacostraca External metabolites in sea water Arthropoda V: Functional morphology of jaws and other things in the Crustacea Arthropoda VI : Pycnogonida and Xiphosurida Ectoprocta and Entoprocta Aschelminthes Mollusca IV : Functional morphology in Cephalopoda and minor groups Physiology of parasitic flatworms Annelida I : Introduction, reproduction and development Annelida II : Settling of larvae, regeneration, feeding and locomotion Annelida III: Respiration, osmoregulation, neuromuscular system and behavior Arthropoda I : Introduction to the Crustacea : The biology of limbs and exoskeleton Porifera II Platyhelminth.es I : Turbellaria and Trematoda Platyhelminthes II : Cestoda and Rhynchocoela Mollusca I : General molluscan organization functioning of mantle cavity in Gastropoda Mollusca II : Gastropoda mantle cavity and feeding mech- anisms in Bivalvia Mollusca III : Adaptations in bivalves aspects of general physiology of Gastropods and bivalves Cnidaria I : General diversity in hydroids Cnidaria II : Hydroid morphogenesis Cnidaria III : Other Cnidaria physiology of Cnidaria Ctenophora Porifera I MARINE ECOLOGY I. CONSULTANTS MELBOURNE R. CARRIKER, Marine Biological Laboratory BOSTWICK H. KETCHUM, Woods Hole Oceanographic Institution EDWIN T. MOUL, Rutgers University JOHN H. RYTHER, Woods Hole Oceanographic Institution 20 MAKIXE BIOLOGICAL LABORATORY II. INSTRUCTORS \V. ROWLAND TAYLOR, Department of Oceanography and the Chesapeake Bay Institute, The Johns Hopkins University, in charge of course HOWARD L. SANDERS, Woods Hole Oceanographic Institution LAWRENCE B. SLOBODKIN, Department of Zoology, University of Michigan RICHARD A. BOOLOOTIAN, Department of Zoology, University of California at Los Angeles OTTO KINNE, Biologische Anstalt Helgoland III. LABORATORY ASSISTANTS MARGARET C. LLOYD, University of Michigan BARRY M. HEATFIELU, University of California at Los Angeles W. ROWLAND TAYLOR \Y. ROWLAND TAYLOR W. ROWLAND TAYLOR W. ROWLAND TAYLOR W. ROWLAND TAYLOR YV. ROWLAND TAYLOR M. R. CARRIKER J. H. RYTHER D. MENZEL W. R. TAYLOR B. H. KETCHUM E. R. BAYLOR H. L. SANDERS II. L. SANDERS R. SCHELTEMA H. L. SANDERS ERIC L. MILLS J. B. PF.ARCE S. A. WAINRIGHT J. A. HELLEBUST OTTO KTNNE L. I'ROVASOLI L. PROVASOLI OTTO KINNE L. I'RMVASOT.I ' )TTO KIN.NE IV. LECTURES Organisms and their environment experimental approaches The marine environment, its chemistry and physics Phytoplankton I : Diatoms Phytoplankton II: Dinoflagellates Primary productivity by phytoplankton I Primary productivity by phytoplankton II The Systematics-Ecology Program at the Marine Biologi- cal Laboratory Geographical variations in productivity Production and utilization of dissolved organic material in the oceans Physiology of migrating littoral diatoms Nutrient cycles in the sea Sea surface chemistry and the distribution of organisms Animal-sediment relationships A study of a marine benthic community Problems in benthic larval ecology Salinity, hydrography and the distribution of estuarine animals Ecology of a crustacean sibling species pair, or systematics unashamed Temporal and spatial distribution of mytilid associations Biology of reef corals Excretion of organic compounds by marine algae The effects of temperature on marine and brackish water organisms Culturing marine algae I : (Joint lecture with the Botany Course) Culturing marine algae II: (Joint lecture with the Botany Course) Effects of temperature and salinity on the hydroid, Cordylo- f>!n>ru cuspid External metabolites in sea water Kffects of temperature, salinity and oxygen on the fish. Cyprinodan iihicitltirins REPORT OF THE DIRECTOR 21 A. FARMANFARMAIAN Temperature and salinity tolerance limits of the West Coast purple sea urchin OTTO KINNE Non-genetic adaptation to temperature and salinity in marine and brackish water organisms L. SLOBODKIN Ecological tautologies L. SLOBODKIN Fecundity, mortality and reproductive value L. SLOBODKIN Experimental population growth L. SLOBODKIN Energy and animal populations L. SLOBODKIN The strategy of evolution R. A. BOOLOOTIAN Food requirements and distribution of marine organisms : general considerations R. A. BOOLOOTIAN Types of food utilization by marine organisms with em- phasis on feeding adaptions R. A. BOOLOOTIAN Reproductive biology of marine organisms : General pat- terns R. A. BOOLOOTIAN Factors influencing the regulation of reproductive cycles R. A. BOOLOOTIAN Reproductive physiology of the purple sea urchin, Strongy- loccntrotus pitrpuratus Wednesday Evening Lecture Series, jointly sponsored by Marine Ecol- ogy, Invertebrate Zoology and Comparative Physiology : N. D. MARSHALL Some aspects of the biology of benthic deep-sea fishes J. H. WELSH Serotonin : Its occurrence in nature and its multiple bio- logical roles CARROLL M. WILLIAMS Light, brains, and metamorphosis B. C. ABBOTT Excitation-contraction coupling and mechanical responses in relation to muscle function SYSTEMATICS-ECOLOGY PROGRAM THE STAFF Director: MELBOURNE R. CARRIKER Resident Systematist : VICTOR A. ZULLO Resident Ecologist : ROBERT H. PARKER Postdoctoral Fellows and Research Associates: MARVIN CANTOR, JOHN C. H. CARTER, DAVID C. GRANT, JACK B. PEARCE, KAY W. PETERSEN, THOMAS J. M. SCHOPF, JOSEPH SIMON, EDMUND H. SMITH, GERALD E. WALSH Visiting Investigators in Residence: RICHARD A. BOOLOOTIAN, LOUISE BUSH, DUANE HOPE, E. T. MOUL Secretaries: SAN LINEA WEAVER, VIRGINIA SMITH Artists: RUTH VON ARX, DIANE JOHNSON Captain of Research Vessel : JAMES P. W. OSTERGARD, JR. Research Assistants: KAY CRAM, ANDREW L. DRISCOLL, J. STEWART NAGLE, PETER J. OLDHAM, PETER E. SCHWAMB, DIRK VAN ZANDT, HILARY M. WILLIAMS, JUNE THOMAS, VILIA TURNER I. SEMINARS (winter not included) ALBERT SZENT-GYORGYI Contraction of muscle JOHN H. RYTHER U. S. Biological Program of the Indian Ocean Expedition VICTOR A. ZULLO Keys to marine invertebrates of the Woods Hole region 22 MARINE BIOLOGICAL LABORATORY JACK B. PEARCE JAMKS ROSS JOSEPH L. SIMON RICHARD A. BOOLOOT IAN- ERIC L. MILLS WALTER R. UKRXDOX MARVIN CANTOR MARVIN CANTOR DAVID C. GRANT COPELAND MACCLINTOCK MELBOURNE R. CARRIKER JACK B. PEARCE DONALD F. SQUIRES ROBERT H. PARKER THOMAS J. M. SCHOPF KAY W. PETERSEN ROBERT R. HESSLER DARYL SWEENEY A preliminary report on the MytHns ednlis association in Ouicks Hole, Kli/al>eth Islands, Massachusetts Electrometric measurements of activities of ions and gases as applied to measurements in animals and of sea water Reproduction and larval development in the spionid poly- chaete, Spio setosa Aspects of reproductive biology of echinoderms The biology oi an amphipod crustacean sibling species pair Some approaches to taxonomic revision in chlorophycean algae Adaptation in a flagellate protozoan Metabolic adaptation in a flagellate protozoan Specific diversity in an intertidal community Microstructure of the shell in Gastropoda An aerial overview of the major marine habitats of the Cape Cod region A pilgrimage to Ellerslie (P.E.I., Canada) and its sur- rounding benthic communities Fossil coral thickets The 1958-59 Downwind Expedition to Easter Island Conodonts of the Trenton Group (Ordovician) in New York and Southern Ontario, Canada On the origin of Metazoa Derocheilocaris typicus revisited What good is dopamine; clams; biochemical evolution? THE LABORATORY STAFF HOMER P. SMITH, General Manager Miss JANE FESSENDEN, Acting Librarian CARL O. SCHWEIDENBACK, Manager, Supply Department IRVINE L. BROADBENT, Office Man ROBERT KAHLER, Superintendent, Buildings and Grounds ROBERT B. MILLS, Manager, De- partment of Research Service JERAL OFFICE EDWARD J. BENDER MRS. VIVIEN B. BROWN MRS. FLORENCE S. BUTZ MRS. MARION C. CHASE MRS. VIRGINIA HKAXDENI'.UKC MKS. LKNOR \ Josi MI LIBRARY MRS. JUDITH A. KECK MRS. ANN W. LOOMIS MRS. VIVIAN I. MANSON Miss KATHERINE M. TRACY ALBERT K. NEAL MRS. DORIS T. RICKI-K MAINTENANCE oh' BUILDINGS AND GROUNDS ADAMS KI.DON P. ALLEN BERNARD F. CAVANAUGH MANUEL P. DUTRA S I AX LEY C. El.DKKDCK ( i ARUM. R V. GAYTON KOP.KKT GUNNING DONALD B. LEIIY l\ M.PII H. LEWIS KrssKi.L F. LEWIS I IKXRY !". POTTER ROBERT H. WALKER, JR. REPORT OF THE DIRECTOR DEPARTMENT OF RESEARCH SERVICE GAIL M. CAVANAUGH Miss MARGARET E. SCOTT LOWELL V. MARTIN FRANK E. SYLVIA SUPPLY DEPARTMENT ARNO J. BOWDEN PAUL SHAVE DAVID H. GRAHAM BRUNO F. TRAPASSO MRS. E. GREEN JOHN J. VALOIS ROBERT W. HAMPTON HALLETT S. WAGSTAFF ROBERT O. LEHY DINING HALL AND HOUSING ROBERT T. MARTIN, Manager, Food Service MRS. ELIZABETH KUIL, Supervisor, Dining Room MRS. ELLEN T. NICKELSON, Supervisor, Dormitories ALAN G. LUNN, Supervisor, Cottage Colony 3. INVESTIGATORS : LALOR, LILLIE AND GRASS FELLOWS ; STUDENTS Independent and Beginning Investigators, 1964 ABBOTT, BERNARD C, Professor of Physiology and Biophysics, University of Illinois ADELBERG, EDWARD A., Professor and Chairman, Department of Microbiology, Yale University ADELMAN, WILLIAM J., JR., Associate Professor of Physiology, University of Maryland ALLEN, ROBERT DAY, Associate Professor of Biology, Princeton University ANDERSON, EVERETT, Professor of Zoology, University of Massachusetts ARMSTRONG, PHILIP B., Chairman, Department of Anatomy, State University of New York, College of Medicine at Syracuse ARNOLD, JOHN M., Lerner Marine Laboratory of the American Museum of Natural History AUCLAIR, WALTER, Assistant Professor of Zoology, University of Cincinnati AUSTIN, C. R., Member of External Scientific Staff, Medical Research Council of Great Britan BAKER, ROBERT F., Radiation Physicist, Brown University BANG, FREDERIK B., Professor of Pathobiology, The Johns Hopkins University BARDACH, JOHN E., Professor of Zoology, University of Michigan BARLOW, ROBERT B., The Rockefeller Institute EARTH, L. G., Professor of Zoology, Columbia University BARTH, L. J., Professor of Zoology, Barnard College BAUER, G. ERIC, Profesor of Anatomy, University of Minnesota BAUMANN, FRITZ, National Institute of Neurological Diseases and Blindness, National In- stitutes of Health BAYLOR, MARTHA BARNES, Marine Biological Laboratory BEATTY, RICHARD ALAN, Senior Principal Scientific Officer, Agricultural Research Council Unit of Animal Genetics, Great Britain BELAMARICH, FRANK A., Assistant Professor of Biology, Boston University BELL, EUGENE, Associate Professor of Biology, Massachusetts Institute of Technology BENNETT, M. V. L., Associate Professor of Neurology, Columbia University, College of Physicians and Surgeons BIGGERS, JOHN D., Professor of Reproductive Physiology, University of Pennsylvania BILLIAR, REINHART B., Research Fellow, Harvard Medical School BINSTOCK, LEONARD, Electronic Engineer (Instrumentation), National Institutes of Health BOOLOOTIAN, RICHARD A., Associate Professor of Zoology, University of California, Los Angeles BRANDT, PHILLIP W., Assistant Professor of Anatomy, Columbia University BRANHAM, JOSEPH M., Assistant Professor of Biology, Oglethorpe University 24 MARINE BIOLOGIC \l. LABI iRATORY BRINLEY, F. J., Assistant Professor of Physiology, Tlie Johns Hopkins School of Medicine BROWX, DOXALD D., Staff Member in Biochemistry, Carnegie Institution of Washington BROWN, FRANK A., JR., Morrison Professor of Biology, Northwestern University BRYAXT, S. H., Associate Professor of Pharmacology, University of Cincinnati BRZIN, MIRO, Senior Research Associate, University of Ljubljana BURCH, HELEN B., Associate Professor of Pharmacology, Washington University BURNETT, ALLISON L., Associate Professor of Biology, Western Reserve University CANTOR, MARVIN H., Postdoctoral Fellow, Systematics-Ecology Program, Marine Biological Laboratory CARLSON, FRANCIS D., Chairman and Professor of Biophysics, The Johns Hopkins University CARRIKER, MELBOURNE R., Director, Systematics-Ecology Program, National Institutes of Health CARTER, JOHX. Postdoctoral Fellow, Systematics-Ecology Program, Ford Foundation CHENEY, RALPH HOLT, Professor of Biology, Brooklyn College, The City University of New York CHILD, FRANK M., Assistant Professor of Zoology, University of Chicago CLAFF, C. LLOYD, Treasurer and Chief Investigator, Single Cell Research Foundation, Inc. CLARK, ELOISE E., Assistant Professor of Zoology, Columbia University CLEMENT, A. C., Professor of Biology, Emory University COLE, KEXNETH S., Chief, Laboratory of Biophysics, NINDB, National Institutes of Health COLWIN, ARTHUR L., Professor of Biology, Queens College, The City University of New York COLWIN, LAURA HUNTER, Lecturer in Biology, Queens College, The City University of New York COOK, PHILIP WILLIAM, Assistant Professor of Botany, University of Vermont COOPERSTEIX, SHERWIN J., Associate Professor of Anatomy, Assistant Dean, Medical School, Western Reserve University COPELAND, EUGENE, Chairman and Professor of Zoology, Tulane University COSTELLO, DONALD PAUL, Kenan Professor of Zoology, University of North Carolina CROWELL, SEARS, Professor of Zoology, Indiana University DEHAAX, ROBERT L., Research Embryologist, Carnegie Institution of Washington DE LORENZO, A. J., Director, Anatomical and Pathological Research Laboratories, The Johns Hopkins University School of Medicine DETTBARN, WOLF-DIETRICH, Assistant Professor of Neurology, Columbia University, College of Physicians and Surgeons DE VILLAFRANCA, GEORGE W., Professor of Zoology, Smith College DISCHE, ZACHARIAS, Professor of Biochemistry, Columbia University, College of Physicians and Surgeons DUNHAM, PHILIP B., Assistant Profesor of Zoology, Syracuse University EBERT, JAMES D., Director, Department of Embryology, Carnegie Institution of Washington ECKERT, ROGER, Assistant Professor of Zoology, Syracuse University EDDS, MAC V., JR., Chairman and Professor of Medical Science, Brown University EHRENSTEIN, GERALD, Physicist, National Institutes of Health ESKRIDGE, ROSEMARY WAITE, Special Research Assistant of Biochemistry, State University of New York at Huffalo EVOY, WILLIAM H., Grass Fellow, University of Oregon FAILLA, PATRICIA MCQ.EMEXT, Associate Biophysicist, Argonne National Laboratory FARMANFARMAIAN, ALLAIIVERDI, Professor of General Physiology, Pahlavi University, Shiraz, Iran FISHER, FRANK M., JR., Assistant Professor of Biology, Rice University FISHMAX, Louis, Assistant Research Professor, New York University College of Dentistry FREEMAN, ALAN R., Postdoctoral Trainee Fellow USPHS, Columbia University Fi:r.MF.XTO, ANTONIO S., Postdoctoral Fello\v, University of Maryland FUJIO, HAJIME, Department of Microbiology, University of Pennsylvania Medical School FUORTES, M. G. F., Head, Section on Ncurophysiology, NINDB, National Institutes of Health !ii 1 1 PAN. EDWIN J., Assistant Professor of Neurophysiology, Harvard Medical School GARCIA, HORATIO A., Grass Fellow, Columbia University GEILENKIRCIIKX, W. I.. M.. I.crtnn-r, University of I'tivrlit. Holland REPORT OF THE DIRECTOR 25 GELFANT, SEYMOUR, Associate Professor of Zoology, Syracuse University GERMAN, JAMES L., Ill, Director and Associate Professor of Division of Human Genetics, Cornell University Medical School GIBBO'NS, I. R., Assistant Professor, Biological Laboratories, Harvard University GILBERT, DANIEL L., Physiologist, National Institutes of Health GIMENEZ, MAXIMO, Grass Fellow, Columbia University, College of Physicians and Surgeons GLADE, RICHARD W., Chairman and Associate Professor of Zoology, University of Vermont GOLDMAN, LAWRENCE, Postdoctoral Fellow, Columbia University, College of Physicians and Surgeons GRANT, DAVID, Research Associate, Systematics-Ecology Program GRANT, PHILIP, Program Director, Developmental Biology, National Science Foundation GREEN, JONATHAN, Postdoctoral Research Fellow, The Johns Hopkins University GREY, HOWARD, The Rockefeller Institute GROSCH, DANIEL S., Professor of Genetics, North Carolina State of the University of North Carolina at Raleigh GROSS, PAUL R., Associate Professor of Biology, Brown University GRUNDFEST, HARRY, Professor of Neurology, Columbia University, College of Physicians and Surgeons GUTTMAN, RITA, Associate Professor of Biology, Brooklyn College HADORN, E., Director, Zoologisch-Vergl. Anatomisches Institut, Der Universitat Zurich, Switzerland HAGINS, WILLIAM A., NIAMD, National Institutes of Health HALVORSON, H. O., Professor of Bacteriology, University of Wisconsin HARDING, CLIFFORD V., Associate Professor of Physiology, Columbia University, College of Physicians and Surgeons HAROSI, FERENC, Electronics Engineer, The Rockefeller Institute HASTINGS, J. WOODLAND, Professor of Biochemistry, University of Illinois HAYASHI, TERU, Chairman and Professor of Zoology, Columbia University HEGYELI, ANDREW, Institute for Muscle Research, Marine Biological Laboratory HERNDON, WALTER R., Head and Professor of Botany, University of Tennessee HERVEY, JOHN P., Senior Electronics Engineer, The Rockefeller Institute HIGASHINO, SHOJI, Research Associate in Physiology, Gunma University, Japan and Columbia University HIGGINS, DON CHENEY, Assistant Professor of Internal Medicine, Yale University HIRAMOTO, YUKIO, Assistant Professor at Misaki Marine Biological Station, University of Tokyo HOLZ, GEORGE G., Chairman and Professor of Microbiology, State University of New York, Upstate Medical Center HOPE, WILLIAM DUANE, Associate Curator, Division of Marine Invertebrates, United States National Museum HOSKIN, FRANCIS C. G., Assistant Professor of Neurology, Columbia University, College of Physicians and Surgeons HUMPHREYS, TOM, Assistant Professor of Biology, Massachusetts Institute of Technology HUNTER, W. D. RUSSELL, Professor of Zoology, Syracuse University HUVER, CHARLES W., Assistant Professor of Anatomy, University of Illinois INOUE, SHINYA, Chairman and Professor of Cytology, Dartmouth Medical School ISENBERG, IRVIN, Institute for Muscle Research, Marine Biological Laboratory JANOFF, AARON, Assistant Professor of Pathology, New York University School of Medicine JOHNSON, FRANK H., Professor of Biology, Princeton University KAMINER, BENJAMIN, Institute for Muscle Research. Marine Biological Laboratory KANE, ROBERT E., Assistant Professor of Cytology, Dartmouth Medical School KARLIN, ARTHUR, Research Associate, Columbia University, College of Physicians and Surgeons KARASAKI, SHUICHI, Biology Division, Oak Ridge National Laboratory KARUSH, FRED, Professor of Microbiology, University of Pennsylvania Medical School KATZ, GEORGE M., Electronics Engineer, Columbia University, College of Physicians and Surgeons KALEY, GABOR, Assistant Professor of Pathology, New York University 26 MAkiXK BIOLOGICAL LABORATORY KEMPTON, RUDOLF T., Professor of Zoology, Vassar College KEOSIAN, JOHN, Professor of Biology, Rutgers The State University KESSEL, RICHARD G., Assistant Professor of Zoology, State University of Iowa KING, THOMAS J., Head, Department of Embryology, The Institute for Cancer Research KINXE, OTTO, Director and Professor of Biologische Anstalt Helgoland, Hamburg-Altona, Palmaille, 9, Germany KLEIN HOLZ, LEWIS H., Professor of Biology, Reed College KORNBERG, HANS LEO, Head, Professor of Biochemistry, University of Leicester, England KRASSNER, STUART AT., The Rockefeller Institute KRISHNAKUMARAN, A., Postdoctoral Research Fellow, Western Reserve University KUFFLER, STEPHEN W., Professor of Neurophysiology, Harvard University LANSING, ALBERT, Professor of Anatomy, University uf Pittsburgh LASH, JAMES W., Assistant Professor of Anatomy, University of Pennsylvania Medical School LASTER, LEONARD, Chief of Gastroenterology Unit, National Institute of Arthritis and Metabolic Diseases LAZAROW, ARNOLD, Head and Professor of Anatomy, University of Minnesota LECAR, HAROLD, Physicist, National Institutes of Health LERMAN, SIDNEY, Associate Professor of Ophthalmology & Assistant Professor of Bio- chemistry, University of Rochester School of Medicine & Dentistry LEVINE, LAWRENCE, Professor of Biochemistry, Brandeis University LEVY, MILTON, Chairman and Professor of Biochemsitry, New York University College of Dentistry LIEBMAN, PAUL A., Assistant Professor of Physiology, University of Pennsylvania LOEWENSTEIN, WERNER R., Associate Professor of Physiology, Columbia University, College of Physicians and Surgeons LOPEZ, ENRIQUE, Research Associate in Neurology, Columbia University, College of Physicians and Surgeons LORAND, L., Professor of Chemistry, Northwestern University LOVE, WARNER E., Associate Professor of Biophysics, The Johns Hopkins University MAcNiCHOL, EDWARD F., Professor of Biophysics, The Johns Hopkins University MAGGIO, RACHELE, Assistant Professor, Institute of Comparative Anatomy, University of Palermo, Italy MAHLER, HENRY R., Professor of Chemistry, Indiana University MALKIN, LEONARD I., Research Associate of Biology, Brown University MARCHALONIS, JOHN, The Rockefeller Institute MARMASSE, CLAUDE, The Commonwealth Fund, Marine Biological Laboratory MARSLAND, DOUGLAS, Research Professor, New York University McELROY, W. D., Professor of Biology, The Johns Hopkins University MELLON, DEFOREST, JR., Assistant Professor of Biology, University of Virginia MENDELSON, MARTIN, Professor in Physiology, New York University METZ. CHARLES B., Professor of Biologj in the Institute for Space Biosciences, Florida State University MILEIJI, Ku AKIIO, Reader in Biophysics, University College of London, England MILKMAN, ROGER DAWSON, Associate Professor of Zoology, Syracuse University MILLER, FAITH S., Assistant Professor of Anatomy, Tulane University MILLER, JAMES A., Professor and Chairman of Anatomy, Tulane University MOIILER, J. D., Associate Professor of Zoology, Oregon State University MOHRI, HIDEO, Research Associate of Biology, University of Tokyo MONROY, ALBERTO, Professor of Comparative Anatomy, University of Palermo, Italy MOORE, JOHN W., Associate Professor of Physiology, Chief, Laboratory of Cellular Neuro- physiology, Duke University MOSCONA, A. A., Professor of Zoology, University of Chi( Mn.i.ixs, L. J., Professor of Biophysics, University of Maryland NACE, PAUL FOLEY, Professor, Research Unit in Molecular Biology, McMaster University, Canada NAQAI, REIKO, Research Associate of Biology, Princeton University NAKAMURA, YUTAKA, Research Fellow, Columbia University, College of Physicians and Surgeons REPORT OF THE DIRECTOR NASATIR, MAIMON, Assistant Professor and Assistant to the Dean, Pembroke College NELSON, LEONARD, Associate Professor of Physiology, Emory University NICHOLS, H. WAYNE, Assistant Professor of Botany, Washington University at St. Louis NVBORG, WESLEY L., Professor of Physics, University of Vermont OKAZAKI, KAYO, Research Associate, Tokyo Metropolitan University ; University of Penn- sylvania PARKER, ROBERT H., Resident Ecologist, Systematics-Ecology Program, National Science Foundation PARPART, ARTHUR K., Chairman and Professor of Biology, Princeton University PEARCE, JOHN BODELL, Research Associate, Systematics-Ecology Program, National Science Foundation PERSON, PHILIP, Chief, Special Dental Research Laboratory, VA Hospital, Brooklyn PORTER, KEITH R., Head and Professor of Biological Laboratories, Harvard University RABIN, HARVEY, Assistant Professor of Pathology, The Johns Hopkins University RASMUSSEN, ROSEMARY CROCKETT, Research Associate, State University of New York, Up- state Medical Center READ, CLARK P., Professor of Biology, Rice University REBHUN, LIONEL L, Associate Professor of Biology, Princeton University REPORTER, MINOCHER, Carnegie Institution of Washington REUBEN, JOHN P., Assistant Professor of Neurology, Columbia University, College of Phy- sicians and Surgeons RICE, ROBERT V., Senior Fellow, Mellon Institute ROSE, S. MERYL, Professor of Experimental Embryology, Tulane University ROSENBERG, PHILIP, Assistant Professor in Neurology, Columbia University, College of Physicians and Surgeons ROSENKRANZ, HERBERT S., Assistant Professor of Microbiology, Columbia University, College of Physicians and Surgeons ROSLANSKY, JOHN D., Institute for Muscle Research, Marine Biological Laboratory ROTH, JAY S., Professor of Biochemistry, University of Connecticut RUGH, ROBERTS, Associate Professor of Radiology (Biology), Columbia University RUSTAD, RONALD C, Associate Professor of Biology, Western Reserve University SANDERS, HOWARD L., Research Associate in Ecology, Woods Hole Oceanographic Institution SATO, HIDEMI, Assistant Professor of Cytology, Dartmouth Medical School SAUNDERS, JOHN W., Chairman and Professor of Biology, Marquette University SCHNEIDERMAN, HOWARD A., Chairman and Professor of Biology, Western Reserve University SCHMEER, SISTER M. ROSARII, Co-Director of Research, St. Mary of the Springs SCHNITZLER, RONALD MICHAEL, Research Fellow, University of Vermont SCHOPF, THOMAS J. M., Postdoctoral, Systematics-Ecology Program, Ford Foundation SCHUEL, HERBERT, Postdoctoral Fellow, Northwestern University SCOTT, ALLAN C., Professor of Biology, Colby College SCOTT, SISTER FLORENCE MARIE, Chairman and Professor of Biology, Seton Hill College SCOTT, GEORGE T., Chairman and Professor of Biology, Oberlin College SENFT, JOSEPH P., USPHS Postdoctoral Fellow, University of Maryland SHAW, CHARIS, Research Associate, Tulane University SHEMIN, DAVID, Professor of Biochemistry, Columbia University SHERMAN, IRWIN W., Assistant Professor of Zoology, University of California, at Riverside SICHEL, F. J., Chairman and Professor of Physiology and Biophysics, College of Medicine, University of Vermont SIMON, JOSEPH L., Sandeen Memorial Fellow, University of Florida SIMPSON, SIDNEY B., JR., Postdoctoral Fellow, Department of Anatomy, Western Reserve Medical School SINGER, IRWIN, Research Associate, National Institute of Mental Health SJODIN, RAYMOND A., Associate Professor of Biophysics, University of Maryland SLATER, CLARKE ROTHWELL, Grass Fellow, University College, London, England SLOBODKIN, LAWRENCE B., Professor of Zoology, University of Michigan SMELSER, GEORGE K., Professor of Anatomy, Columbia University SMITH, EDMUND H., National Institutes of Health Fellow, Systematics-Ecology Program MARINE BIOLOGICAL LABORATORY SMITH, THOMAS GRAVES, Research Neurophysiologist, NINDB, National Institutes of Health SMITH, WILLIAM ROY, School of Hygiene & Public Health, The Johns Hopkins University SPEIDEL, CARL C, Professor of Anatomy, University of Virginia SPINDEL, WILLIAM, Professor of Chemistry, Rutgers University SPIRTES, M. A., Associate Professor of Pharmacology, Hahnemann Medical College STEINBACH, H. BURR, Chairman and Professor of Zoology, University of Chicago STRITTMATTER, PIIILIPP, Associate Professor of Biochemistry, Washington University STU.XKAKD, HORACE W., Research Associate, American Museum of Natural History SURGENOR, DOUGLAS M., Dean of Medical School, Chairman of Biochemistry, State University of New York at Buffalo SzAB6, GEORGE, Assistant Professor of Anatomy, Harvard Medical School SZEXT-GYORGYI, ALBERT. Director and Chief Investigator, Institute for Muscle Research, Marine Biological Laboratory TAKATA, MITSURU, Assistant Professor of Physiology, Duke University TAKENAKA, TOSIIIKUMI, National Institutes of Health TASAKI, ICHIJI, Acting Chief, Laboratory of Neurobiology, NIMH, National Institutes of Health TAYLOR, PETER, Postdoctoral Fellow, Systematics-Ecology Program, National Science Foundation TAYLOR, ROBERT E., Associate Chief, Biophysics Laboratory, NINDB, National Institutes of Health TAYLOR, WALTER ROWLAND, Assistant Professor of Oceanography, The Johns Hopkins University TENCER, RENEE, Assistant, University of Brussels, Brussels TILNEY, LEWIS G., Postdoctoral Fellow, Harvard University TORCH, REUBEN, Associate Professor of Zoology, University of Vermont TRAVIS, DAVID M., Assistant Professor of Pharmacology & Therapeutics, University of Florida College of Medicine TRINKAUS, J. P., Professor of Biology, Yale University TROLL, WALTER, Associate Professor, New York University Medical Center, Institute of Industrial Medicine TWEEDELL, KENYON S., Associate Professor of Biology, University of Notre Dame USHERWOOD, PETER N. R., Research Associate, Columbia University, College of Physicians and Surgeons VAN HOLDE, K. E., Associate Professor of Chemistry, University of Illinois VAN VUNAKIS, HELEN, Associate Professor of Biochemistry, Brandeis University \Y.\i.D, GEORGE, Professor of Biology, Harvard University WALLACE, ROBIN A., Research Associate, Biology Division, Oak Ridge National Laboratory WALSH, GERALD EDWARD, Postdoctoral Research Associate, Systematics-Ecology Program, National Science Foundation WATKINS, DUDLEY T., Research Fellow, Department of Anatomy, Western Reserve Medical School :, If. MARGUERITE, Associate Professor, Research Assistant, Gouchcr College and North- western University WEISS, LEON, Associate Professor of Anatomy, The Johns Hopkins University School of Medicine WICHTERMAN, RALPH, Professor of Biology, Temple University WILCE, R. T., Assistant Professor of Botany, University of Massachusetts WILSON, WALTER L., Associate Professor of Physiology and Biophysics, University of Vermont College of Medicine WINTERS, ROBERT W., Professor of Pediatrics & Career Scientist, Columbia University, College of Physicians and Surgeons WYTTENBACII, CHARLES R., Assistant Professor of Anatomy, University of Chicago ZIGMAN, S., Instructor in Biochemistry, University of Rochester ZIMMERMAN, ARTHUR M., Assistant Professor of Pharmacology, State University of New York, Downstate Medical Center /i i i.o, VICTOR A., Assistant Director, Resident Systematist. Systematics-Ecology Program, Ford Foundation REPORT OF THE DIRECTOR 29 Lalor Fellows, 1964 RICHARD ALAN BEATTY, Senior Fellow, Agricultural Research Council Unit of Animal Genetics, United Kingdom JOSEPH M. BRANHAM, Oglethorpe University YUKIO HIRAMOTO, Misaki Marine Biological Station, Japan CHARLES W. HUVER, University of Illinois RACHELE MAGGIO, University of Palermo, Italy HIDEO MOHRI, University of Tokyo, Japan ROBERT W. WINTERS, Columbia University, College of Physicians and Surgeons Lillie Fellow, 1964 E. HADORN, Der Universitat Zurich, Switzerland Grass Fellows, 1964 NEIL DAVIDSON, State University of New York, Downstate Medical Center, Brooklyn WILLIAM H. EVOY, University of Oregon HORACIO A. GARCIA, Columbia University, College of Physicians and Surgeons MAXIMO GIMENEZ, Columbia University, College of Physicians and Surgeons RICARDO MILEDI, Forbes Lecturer, University College, London CLARKE ROTHWELL SLATER, University College, London Research Assistants, 1964 ACQUAVIVA, PATRICIA ANN, Seton Hill College ALTSHULER, BERNARD, New York University Medical Center ANONELLIS, BLENDA C., Western Reserve University APICELLA, JAMES V., University of Pittsburgh ARDWIN, LINDSAY, S., Columbia University ^ ARMSTRONG, JUDY, Western Reserve University ARONSON, WENDY S., Vassar College ASHWORTH, JOHN MICHAEL, Leicester University, England BAIRD, SPENCER L., Institute for Muscle Research BARNHILL, ROBERT, Capitol Radio Engineering Institute BERRIEN, JUDI, Princeton University BIKLE, DANIEL, Harvard University BLAIR, MARION H., McMaster University, Canada BLUMENTHAL, DANIEL S., Oberlin College BOLLINGER, M. SUSAN, University of Maryland BRADY, FRANCINE, Syracuse University BREVER, ANTHONY CARL, Princeton University BRUNGARD, JOANNE, Harvard Medical School BURGER, RICHARD, Princeton University GARDEN, GEORGE ALEXANDER, III, Columbia University, College of Physicians and Surgeons CHAFFEE, RICHARD B., JR., Syracuse University CHAGNON, SUZANNE, University of Vermont CHANY, AMOS HWEI-CHEH, Columbia University CHASIS, JOEL ANNE, New York University School of Medicine GROUSE, FRANCES W., Biologische Anstalt Helgoland DANIELS, CHARLES, Duke University DAVIDSON, NEIL, State University of New York DE LUCA, MARLENE, The Johns Hopkins University DIMINO, PATRICIA, Columbia University DOANE, MARSHALL G., University of Maryland School of Aledicine DUMONT, JAMES N., University of Massachusetts EISENBERG, HENRY W., Columbia University FEDOROFF, NINA, Syracuse University 30 MARINE BIOLOGICAL LABORATORY FISHER, EI.I.EN D. B., Columbia University FITZJARRELL, AUSTIN T., Tulane University FORAN, ELIZABETH H., Smith College FREEMAN, SUSAN G., Columbia University Fu, KAREN, Columbia University, College of Physicians and Surgeons GALTON, VIRGINIA, Harvard Medical School GEBELEIN, CONRAD DENNIS, The Johns Hopkins University GEDMINTAS, DANA, University of Chicago GOTTDIENER, DONNA, Vassar College GRAMSS, ELISE, Institute for Muscle Research HARRIS, EDWARD M., Duke University HARVEY, JENETTE, Johns Hopkins School of Medicine HECHTER, MICHAEL, Columbia University HECKMAN, JAMES D., Princeton University HEGAB, EL-SAYED, Tulane University HITCHCOCK, SUSAN M., Columbia University, College of Physicians and Surgeons HODES, BARTON L., Jefferson Medical College JAFFEE, STEPHEN, New York University School of Medicine JOHNSON, KURT E., The Johns Hopkins University KAUFMAN, ROBERT G., Columbia University KEHLENBECK, EDNA, Syracuse University KILEJIAN, ARAXIE, Rice University KIMBALL, FRANCES, Reed College KIRSCHBERG, GORDON J., Columbia University, College of Physicians and Surgeons LARSEN, WILLIAM J., Wesleyan University LESTER, GORDON JAMES, University of Minnesota LEVIXE, MARILYN, Western Reserve University MACNAMARA, GAEL R., Columbia University, College of Physicians and Surgeons MAZIA, JUDITH ANN, University of Chicago McGiLVRAY, JEAN MARIE, 'Dartmouth Medical School McENANEY, BARBARA, Marquette University MEISMER, DONALD M., University of Cincinnati MILLER, SANDRA M., University of Maryland MITTENTHAL, JAY E., The Johns Hopkins University MOHL, ROBERT L., Hahnemann Medical College MOSSER, JERRY L., Indiana University and The Rockefeller Institute MUNDAY, JOHN C., University of Illinois MUNRO, GEORGE F., University of Rochester MUNRO, JUDITH L., University of Rochester MURPHY, ANNE M., University of Maryland NEWMAN, BROOKE, Institute for Muscle Research OLMSTED, CHARLES E., University of Chicago P AIM RE, MARVE, State University of New York, Downstatc Medical Center PANNY, SUSAN R., Columbia University PAWELEK, JOHN M., Brown University POWERS, EARL G., University of Cincinnati RASMUSSEN, LEIF, Carlsberg Foundation RAVITZ, MELVYN J., University of Vermont RAY, PATRICIA, Seton Hill College REALE, VINCENT F., Princeton University RICHMOND, ARTHUR P., Single Cell Research Foundation, Inc. ROBERTSON, C. W., American Museum of Natural History ROSENBLUTH, RAJA, Institute for Muscle Research SANDER, GRETA, Princeton University SCHACHTER, MsRi, Columbia University SETLOW, PETER, Brandeis University SINDELAR, WILLIAM, Western Reserve University SLOANE, ELEANORE M., Mellon Institute REPORT OF THE DIRECTOR 31 SLOANE, MOLLA R., Wellesley College THOMAS, JUNE M., University of California, Los Angeles TOBEY, JOHN H., Maine Vocational Technical Institute TRAVIS, JEANNE D., University of Florida TRENHAFT, PAUL STEVEN, Oberlin College TSUKIDATE, JIUNICHI, Raskins Laboratories TUCKER, ROBERT W., Dartmouth Medical School TURNER, VILIA G., University of California, Los Angeles TUTUNJIAN, JEAN, Columbia University, College of Physicians and Surgeons UEHARA, MARGARET H., University of Hawaii VAN PRAAG, DINA, New York University VASQUEZ, CARMEN, University of Michigan WALDBAUM, MARK, Hahnemann Medical College WASSERMAN, ELEANOR, Brandeis University WEINER, BEVERLY, Harvard University WILSON, LOUISE P., Wellesley College YUYAMA, SHUHEI, Western Reserve University ZOLLINGER, WILLIAM K., JR., University of Pittsburgh Medical School Library Readers, 1964 ATWOOD, KIMBALL C, Professor of Microbiology, University of Illinois BALL, ERIC G., Professor of Biological Chemistry, Harvard Medical School BERNE, ROBERT M., Professor of Physiology, Western Reserve University BRIDGMAN, ANNA JOSEPHINE, Chairman and Professor of Biology, Agnes Scott College BUTLER, ELMER G., Osborn Professor of Biology, Princeton University CARBON, JOHN A., Research Associate, Department of Biochemistry, Abbott Laboratories CHASE, AURIN M., Professor of Biology, Princeton University CLARK, ARNOLD M., Professor of Biology, University of Delaware COHEN, SEYMOUR S., Chairman, Department of Therapeutic Research, University of Penn- sylvania School of Medicine DAVIS, BERNARD D., Head, Department of Bacteriology and Immunology, Harvard Medical School EDER, HOWARD A., Professor of Medicine, Albert Einstein College of Medicine GABRIEL, MORDECAI L., Professor of Biology, Brooklyn College GINSBERG, HAROLD S., Chairman, Department of Microbiology, University of Pennsylvania School of Medicine GREEN, JAMES W., Professor of Physiology, Rutgers University HANDLER, PHILIP, Professor of Biochemistry, Duke University HESSLER, ANITA YOUNG, Marine Biological Laboratory HODES, ROBERT, Research Associate, Department of Neurophysiology, The Mount Sinai Hospital ISSELBACKER, KURT J., Chief, Gastrointestinal Unit, Massachusetts General Hospital and Assistant Professor of Medicine, Harvard Medical School JACOBS, M. H., Emeritus Professor of General Physiology, University of Pennsylvania KALTENBACH, JANE COUFFER, Assistant Professor of Zoology, Mount Holyoke College KASHA, MICHAEL, Director, Institute of Molecular Biophysics, Florida State University KLEIN, MORTON, Professor of Immunology, Temple University Medical School LEIGHTON, JOSEPH, Professor of Pathology, University of Pennsylvania School of Medicine LEVINE, RACHMIEL, Chairman, Department of Medicine, New York Medical School LEVINTHAL, CYRUS, Professor of Biophysics, Massachusetts Institute of Technology LINEAWEAVER, THOMAS H., Ill, Marine Biological Laboratory MARKS, PAUL A., Associate Professor of Medicine, Columbia University, College of Physicians and Surgeons MATEYKO, GLADYS MARY, Associate Professor of Biology, Washington Square College, New York University MEYER, KARL, Professor of Biochemistry, Columbia University MOULTON, JAMES M., Associate Professor of Biology, Bowdoin College MA K I XI-. BIOLOGICAL LABORATORY NASON, ALVIN, Professor of Biology, Associate Director. McCollum-Pratt Institute, The Johns Hopkins University NEEDLEMAN, SAUL B., Senior Research Biochemist, Abbott Laboratories XIIVIKOKF, ALEX B., Research Professor, Albert Einstein College of Medicine XmvoTXY, ALOIS H., Professor of Immunochemistry, Temple University School of Medicine OVERTON, JANE H., Associate Professorial Lecturer in Biology, University of Chicago RAPPORT, MAURICE M., Professor of Biochemistry, Albert Einstein College of Medicine ROWLAND, LEWIS P., Associate Professor of Neurology, Columbia University, College of Physicians and Surgeons RUSSELL, HENRY D., Museum of Comparative Zoology, Harvard University SPIEGEL, MELVIX, Associate Professor of Biology, Dartmouth College SPRAGUE JAMES M., Professor of Anatomy, University of Pennsylvania STETTEN, MARJORIE R., Research Professor, Rutgers Medical School SUDAK, FREDERICK N., Assistant Professor of Physiology, Albert Einstein College of Medicine S \VANSON, CARL P., William D. Gill Professor of Biology, The Johns Hopkins University SZENT-GYORGYI, Andrew G., Professor of Biophysics, Dartmouth Medical School WAINIO, WALTER, Professor of Biochemistry, Rutgers The State University of New Jersey WARNER, ROBERT C., Professor of Biochemistry, New York University School of Medicine WHEELER, GEORGE E., Associate Professor of Biology, Brooklyn College WILSON, THOMAS HASTINGS, Associate Professor of Physiology, Harvard Medical School YNTEMA, CHESTER L., Professor of Anatomy, State University of New York, Upstate Medical Center ZACKS, SUMNER I., Assistant Professor of Neuropathology, Pennsylvania Hospital, Uni- versity of Pennsylvania ZORZOLI, ANITA, Chairman, Professor of Physiology, Vassar College Students, 1964 All students listed completed the formal course program, June 17-July 27. Asterisk indicates students completing Post-Course Research Program, July 28-August 31. ECOLOGY *ADAMSON, JEAN M., Allegheny College ALLESSIO, MARY L., University of Colorado AVERY, PATRICIA P., Wheaton College *BARVENIK, FRANK W., University of Connecticut *BUCHSBAUM, VICKI M., Stanford University *CALDER, WILLIAM ALEXANDER, JR., Duke University GJESSING, HELEN WITTON. College of the Virgin Islands *HEATFIELD, BARRY MARK, University of California JONES, MEREDITH HOWE, Boston University JONES, NANCY GALE, Oberlin College KOETZER, KENNETH L., University of Rhode Island *LLOYD, MARGARET C., Bryn Mawr Colic- r MAYO, CHARLES A., Ill, Dartmouth College OrixN, SISTER GENEVIEVE, Catholic University of America *REA, INA K., Indiana University *RICHARDSON, W. NORMAN, Earlham College WHITE, JOSEPH JAMES, University of Illinois EMBRYOLOGY BARIL, EARL FRANCIS, University of Connecticut BERRILL, MICHAEL, McGill University *CONNEI.L, CAROLYN, Indiana University *DicK, MIRIAM, Brandeis University RKI'OKT OF Til 1C DIRKCTOU *GAEDE, LnRov LEWIS, Rensselaer Polytechnic Institute *GOLDIZEN, VERNON CLAIRE, Western Reserve University ''GOULD, MEREDITH C., Stanford University HAYASHI, MASAKI, University of Illinois *HEIDGER, PAUL ML CLAY, JR., Tulane University *HELD, WILLIAM ALLEN, Marquette University INSELBURG, JOSEPH, Brandeis University KAPLAN, STANLEY, University of Miami *Kopp, LOWELL ELLIS, Massachusetts Institute of Technology *LARSEN, LYNDELL LOUISE, The Rockefeller Institute MORTENSEN, RICHARD, Purdue University *PERCUS, JEROME KENNETH, New York University PRINGLE, JOHN ROBERT, Harvard University *READ, MARGARET TYLER, Harvard University *REIGART, JOHN ROUTT, II, Dartmouth Medical School ROGERS, MARY ELIZABETH, Yale University BOTANY BURG, CAROL ANN, University of Connecticut *BYTNAR, PATRICIA ANN, Seton Hill College CONNER, CLARICE MARIE, University of Wisconsin *HOLT, BUFORD REID, University of Tennessee *HOWELL, STEPHEN H., The Johns Hopkins University KEVIN, SISTER M. PETRA, Fordham University KIES, ROBERT LUDWIG, University of Erlangen, Germany KOCHERT, GARY DEAN, Indiana University *LEE, THOMAS F., Clark University McLEAN, ROBERT J., University of Connecticut *PRINCE, JEFFREY S., University of Massachusetts *RAMUS, JOSEPH STEPHEN, University of California, Berkeley SMITH, JOYCE EILEEN, Cornell University STROTHER, JOHN LANCE, Washington University, St. Louis *TRERICE, ELIZABETH MABEL, Dalhousie University, Halifax, Nova Scotia *URBAN, PAUL, Tufts University WAER, RICHARD DENNIS, University of Arizona *WEBER, JILL LOUISE, Vassar College *WiLcox, ROBERT STIMSON, University of Michigan PHYSIOLOGY *BARBOUR, STEPHEN DAVID, Temple University *BIBER, MICHAEL PETER, University of Chicago Medical School *CAROLAN, ROBERT MILLS, Dartmouth Medical School *CRAIG, NESSLY COILE, University of Pennsylvania ^CONVERSE, CAROLYN ANN, Brown University *ELFBAUM, STANLEY GOODMAN, Northwestern University *ETZLER, MARILYNN EDITH, Washington University, St. Louis GAZITH, JOSEPH, Vanderbilt University GIBERMAN, ELDAD, Massachusetts Institute of Technology *GOLD, LAWRENCE MARSHALL, University of Connecticut *HATLING, DONNA LYNNE, Columbia University *HAUSCHKA, PETER VOORHESS, Amherst College HAYTLER, PETER G., E. I. duPont de Nemours & Company *JURAS, DANUTE, Marquette University *KUBAI, DONNA FAROLINO, University of Wisconsin *LATTMANN, EATON EDWARD, The Johns Hopkins University MARINE BIOLOGICAL LABORATORY *LLOYD, DAVID ALBERT, University of Illinois *MANDEL, MORTON, Stanford University School of Medicine *NICHOLSON, ANNE, University of Pennsylvania School of Medicine DERAZUMNEY, CKLIA ESTER FREDA, University of Pennsylvania School of Medicine ROTHEN STEIN, ARTHUR STANLEY, Rutgers, The State University *SPARKS, HARVEY V., Harvard Medical School SWITZER, SAM, Albert Einstein College of Medicine *TERANDO, SISTER MARY LORETTA, Saint Louis University *TERRELL, KATHLEEN Lois, Columbia University, College of Physicians and Surgeons *\VARD, JOHN CLIVE, The Johns Hopkins University *\\'ARD, RAYMOND LELAND, University of California, Livermure *WECHSLER, JAMES ALAN, Yale University *WEINBERG, ERIC S., The Rockefeller Institute *WHITE, ERIC S., Dartmouth Medical School INVERTEBRATE ZOOLOGY ALLEN, JEFFREY CHARLES, Oberlin College APPLEBAUM, RICHARD, Columbia University BARTIZAL, FREDERICK JOSEPH, Beloit College BENNETT, JUDITH ANN, Syracuse University BOLENDER, ROBERT PAUL, Columbia University BOYD, CARL M., Dalhousie University, Halifax, Nova Scotia CHANE, PAULA FRANCES, Tulane University COGGESHALL, RICHARD EDWIN, Harvard Medical School COTMAN, CARL WAYNE, Wesleyan University DENNAKER, GERMAINE SUZANNE, Morgan State College FISCHER, BARBARA ANN, St. Louis University HALL, BARBARA SUE, College of St. Mary of the Springs HINE, CHARLES RISK, Lafayette College HUNTER, WILLIAM BRUCE, University of California, Santa Barbara JAMPOL, LEE MERRILL, Yale University JOHNSON, KURT EDWARD, The Johns Hopkins University KAUFMAN, ROBERT GORDON, Columbia University KOERING, MARILYN J., University of Wisconsin Koo, HELEN PING-CHING, University of Minnesota LANGRETH, SUSAN GRANT, University of Chicago MEADOWS, ROBERT T., Syracuse University NOLLEN, PAUL MARION, Purdue LIniversity NUTT, JOHN GORDON, JR., Rice University PAGE, CHARLES HENRY, Yale University PAWALEK, JOHN MASON, Brown University PETTIT, BARBARA, Marquette University REUSS, CECILIA MONICA, Marquette University ROBINSON, CAROLYN ANNE, Clark University RUNDLES, CHARLOTTE, Duke University STINE, DEBORAH CLARE, Wilson College TOTH, STEVEN EDWARD, Bowling Green State University TRACY, SUSAN FRANCES, University of Massachusetts WALCOTT, BENJAMIN, University of Oregon WALDRON, INGRID LORE, University of California, Berkeley WALTER, MARY A., Ripon College WALTERS, DAVID ROYAL, Harvard University WARD, OSCAR GARDIEN, JR., Purdue University ;ER, BETSKV ANN, Drew University WHISNANT, BETTY LYNN, Duke University ZEIMEN, SISTER MARIA GORETTI, Catholic University of America REPORT OF THE DIRECTOR 35 4. FELLOWSHIPS AND SCHOLARSHIPS, 1964 Lucretia Crocker Scholarship : VICKI M. BUCHSBAUM, Ecology Course BUFORD R. HOLT, Botany Course Edwin Linton Memorial Endowment of the Washington and Jefferson College: PATRICIA ANN BYTNAR, Botany Course Turtox Scholarship Fund : JOHN BUSHNELL 5. TRAINING PROGRAMS FERTILIZATION AND GAMETE PHYSIOLOGY TRAINING PROGRAM I. INSTRUCTORS C. B. METZ C. R. AUSTIN JOHN BIGGERS ALBERTO MONROY LEONARD NELSON II. ASSISTANTS RACHELE MAGGIO III. STUDENTS R. BERKELEY J. F. FALLON L. E. FRANKLIN M. S. GOROVSKY R. HALLBERG G. S. HAND, JR. S. HAUSCHKA D. L. HESSEL B. HORWITZ M. R. LURIE D. MOORE M. C. REPORTER N. M. SCHULKIND A. E. S. SMITH E. L. STERN D. T. SULLIVAN IV. LECTURES D. SZOLLOSI R. A. BEATTY R. MAGGIO H. MOHRI P. M. BHARGAVE Y. HIRAMOTO R. RlKMENSPOEL R. YANAGIMACHI R. C. RUSTAD L. WEISS Florida State University, in charge of program Cambridge University, England University of Pennsylvania University of Palermo, Italy Emory University University of Palermo, Italy University of Pennsylvania Marquette University Florida State University University of Chicago The Johns Hopkins University University of North Carolina The Johns Hopkins University The Johns Hopkins University Emory University University of Miami University of Pennsylvania Carnegie Institution of Washington New York University, School of Medicine California Institute of Technology University of Chicago The Johns Hopkins University Ultrastructural Studies on Fertilization and the Gametes Genetic Effect on Gametes Activation of Protein Synthesis in the Sea Urchin Egg at Fertilization Mitochondrial Functions of Bull Spermatozoa Ribonucleic Acid and the Amino Acid Incorporation in Spermatozoa Mechanical Properties of the Protoplasm of the Sea Urchin Biophysical Approaches to Problems of Spermatozoan Motility The Hamster as a Material for the Study of Fertilization Radiation Effects in Sea Urchin Gametes Interactions Between Cells Making Contact 36 MARINE BIOLOGICAL LABORATORY I. INSTRUCTORS S. W. KUFFLER E. J. FURSHPAN J. G. NlCHOLLS II. ASSISTANTS NEUROl'lIVSIOLOGY TRAINING PROGRAM Harvard Medical School, in charge of program Harvard Medical School Harvard Medical School R. Bosler Harvard Medical School (No lectures given only seminars) III. STUDENTS J. M. CAMHI A. M. FRIEDLANDER J. HARVEY J. S. McREYNOLDS R. PIPKIN P. STERLING B. WlCKELGREN I. INSTRUCTORS L. KLEINHOLZ B. C. ABBOTT A. JANOFF G. KALEY B. ZWEIFACH Harvard Medical School University of Pittsburgh The Johns Hopkins University Harvard Medical School Harvard Medical School Western Reserve University Massachusetts Institute of Technology COMPARATIVE PHYSIOLOGY TRAINING PROGRAM Reed College, in charge of program University of Illinois New York University New York University New York University II. ASSISTANTS F. KIMBALL J. C. MUNDAY Reed College University of Illinois III. STUDENTS E. A. ASHBY G. M. CONNELL G. A. COTTRELL P. J. DOWD C. R. JONES W. R. KEM M. J. PAR P. STERN University of Texas Indiana University Harvard University Vestibular Laboratory Fordham University University of Illinois LIniversity of Minnesota University of Michigan IV. LECTURES L. KLEINHOLZ G. KALEY A. JANOFF B. C. ABBOTT F. A. BROWN, JR. C. READ R. ALLEN G. COTTRELL Ncurosecretion and Endocrine Physiology Cardiovascular Physiology Comparative Aspects of Lysosome Function & Comparative Aspects of Leucocyte Physiology K\ citation-Contraction Coupling and Relaxing Factor in Muscle A Unified Clock Theory Comparative Aspects of Membrane Transport Cell Movement Binding of Biologically-Active Substances REPORT OF THE DIRECTOR 37 6. TABULAR VIEW OF ATTENDANCE, 1960-1964 1960 INVESTIGATORS TOTAL 458 Independent 273 Library Readers 50 Research Assistants 135 STUDENTS TOTAL 122 Invertebrate Zoology 49 Embryology 20 Physiology 28 Botany 18 Ecology 13 TRAINEES TOTAL Nerve-Muscle Comparative Physiology Fertilization and Gamete TOTAL ATTENDANCE 580 Less persons represented in two categories 2 1961 458 256 49 151 130 40 21 28 19 22 1962 494 279 56 159 121 38 20 28 20 15 1963 1964 490 512 261 273 51 47 178 192 124 40 20 28 20 16 578 INSTITUTIONS REPRESENTED TOTAL , 144 By Investigators 83 By Students 61 SCHOOLS AND ACADEMIES REPRESENTED By Investigators 5 By Students 2 FOREIGN INSTITUTIONS REPRESENTED 14 By Investigators 11 By Students 3 586 1 585 132 107 70 3 28 21 7 615 4 611 118 81 57 3 2 31 17 14 614 5 7. INSTITUTIONS REPRESENTED, 1964 Abbott Laboratories Agnes Scott College Albert Einstein Medical School Allegheny College American Museum of Natural History Amherst College Argonne National Laboratory Arizona, University of Beloit College Boston University Bowdoin College Bowling Green State University Brandeis University Brooklyn College Brown University California, University of, Los Angeles California, University of, Berkeley California, University of, Livermore California, University of, Santa Barbara Capitol Radio Engineering Institute Carnegie Institution of Washington Catholic University of America Chicago, University of, Medical School Chicago, University of Cincinnati, University of Cornell University Cornell University, Medical College Dartmouth College Dartmouth Medical School Delaware, University of Drew University Duke University duPont de Nemours & Company Earlham College Emory University Florida State University Florida, University of Fordham University Goucher College Hahnemann Medical School Harvard University Harvard University Medical School Haskins Laboratories Hawaii, University of Illinois, University of Indiana University Institute for Muscle Research Iowa State University 126 40 20 30 19 17 30 7 7 16 668 7 609 661 120 140 83 117 73 23 4 21 32 15 28 6 4 38 MAKIXK BIOLOGICAL LABORATORY Jefferson Medical College Johns Hopkins University, The Johns Hopkins University School of Medicine, The Lafayette College Lerner Marine Laboratory, of the American Museum of Natural History Maine Vocational Technical Institute Marquette University Maryland, University of Massachusetts General Hospital Massachusetts Institute of Technology Massachusetts, University of Mellon Institute Miami, University of Michigan, University of Minnesota, University of Missouri, University of, Medical School Morgan State College Mount Holyoke College Mount Sinai Hospital, The National Institutes of Health New York State University, College of Medicine at Brooklyn New York State University, College of Medicine at Syracuse New York University, Bellevue Medical Center New York University, School of Dentistry New York University, Washington Square College North Carolina State of the University of North Carolina at Raleigh North Carolina, University of Northwestern University Notre Dame, University of Oak Ridge National Laboratory Oberlin College Oglethorpe University Oregon Regional Primate Research Center Oregon State University Oregon, University of Pembroke College Pennsylvania, University of Pennsylvania Medical School, University of Pittsburgh, University of Princeton University Purdue University Queens College Reed College Rensselaer Polytechnic Institute Rhode Island, University of Rice University Ripon College Rochester, University of, School of Medicine and Dentistry Rockefeller Institute, The Russell Sage College Rutgers, The State University Saint Louis University Seton Hill College Single Cell Research Foundation, Inc. Smith College South Florida College Stanford University Stanford University, School of Medicine State University of New York at Buffalo Swarthmore College Syracuse University Temple University Tennesee, University of Tufts University Tulane University Vassar College Vermont, University of Veterans Administration Hospital Vanderbilt University Virginia, University of Washington University, at St. Louis Wellesley College Wesleyan University Western Reserve University Western Reserve University, School of Medicine Wheaton College Wilson College Wisconsin, University of Yale University FOREIGN INSTITUTIONS REPRESENTED, 1964 Agricultural Research Council of Great Britain Anatomisches Institut, der Universitat Zurich, Switzerland Biologische Anstalt Helgoland, Germany Brussels University, Brussels Dalhousie University, Halifax Erlangen, University of, Germany Gunma University, Japan Leicester University, England Ljubljana University, Yugoslavia Medical Research Council of Great Britain McMaster University, Canada Pahlavi, University of, Shiraz, Iran Queen's University, Ontario, Canada Tokyo, University of, Japan University College, London, England University of Palermo, Italy Utrecht, University of, Holland REPORT OF THE DIRECTOR 39 SUPPORTING INSTITUTIONS, AGENCIES, AND INDIVIDUALS Abbott Laboratories Associates of the Marine Biological Laboratory Atomic Energy Commission CIBA Corporation The Commonwealth Fund Josephine B. Crane Foundation Dr. William D. Curtis The Ford Foundation Dr. and Mrs. David W. Gaiser The Grass Foundation Mr. and Mrs. William H. Greer, Jr. Dr. Ethel Browne Harvey Mr. and Mrs. George F. Jewett, Jr. The Lalor Foundation Mrs. Grace T. Mast Olin Matheson Charitable Trust National Institutes of Health National Science Foundation Office of Naval Research The Rockefeller Foundation Schering Foundation, Inc. Scientific American, Inc. Mr. Gerard Swope, Jr. The Upjohn Company Wallace Laboratories Mr. James H. Wickersham 8. FRIDAY EVENING LECTURES, 1964 July 3 HANS LEO KORNBERG Anaplerotic Sequences in Microbial Metabo- The University of Leicester lism : Their Significance and Regulation July 9, Thursday RICARDO MILEDI Localization of Acetylcholine-Receptors and University College, London Cholinesterase in Muscle Fibres, Part I Alexander Forbes Lecturer at the MBL July 10 RICARDO MILEDI Localization of Acetylcholine-Receptors and Cholinesterase in Muscle Fibres, Part II July 17 IRWIN R. KONIGSBERG Clonal Analysis of Myogenesis Carnegie Institution of Washington July 24 SIDNEY W. Fox Experimental Geosynthesis and a Theory of The Florida State University Cellular Origins July 31 MELBOURNE R. CARRIKER Hard Tissue Destruction by Marine Predatory MBL Gastropods August 7 SOL SPIEGELMAN The Transcription and Translation of Genetic University of Illinois Messages August 14 R. ALAN BEATTY The Gamete as a Microorganism University of Edinburgh Senior Lalor Fellow at the MBL August 21 ERNST HADORN New Patterns of Differentiation Arising in University of Zurich Permanent Cultures of Drosophila Cells in F. R. Lillie Fellow at the MBL vivo August 28 KENNETH D. ROEDER What a Moth's Ear Tells its Nervous System Tufts University about Bats 40 MARINE BIOLOGICAL LABORATORY 9. TUESDAY EVENING SEMINARS, 1964 July 7 H. SCHUEL Isolation of Muscle-Relaxing Particles with L. LORAND the Zonal Centrifuges R. SCHUEL J. S. NAGLE Differential Sorting of Shells in the Swash Zone C. C. SPEIDEL Deviations in Motility of Developing Sea R. H. CHENEY Urchins Induced by Irradiation (film) July 14 J. COHEN The Transfer of Melanin Granules from Me- G. SZABO lanocytes into Malpighian cells of the Mam- malian Epidermis (illustrated with timelapse photography) S. KARASAKI The Sites of Nuclear RNA Synthesis during Amphibian Embryogenesis R. ALAN BEATTY Density Gradient Media for Spermatozoa July 21 S. HIGASHINO Analysis of Biological Excitable Membrane by Means of Voltage-Current-Time Characteristics A. M. ZIMMERMAN Further Studies on Incorporation of H 3 Thymi- L. SILBERMAN dine in Arbacia Eggs Under Hydrostatic Pres- sure D. MARSLAND High Pressure Reversal of the Anti-Mitotic Effects of Heavy Water (D O) July 28 A. JANOFF Production of Inflammatory Changes in the B. ZWEIFACH Micro-Circulation by Cationic Proteins Ex- tracted from Lysosomes H. SATO Condensation of the Sperm Nucleus and Orien- S. INOUE tation of DNA Molecules during Spermiogene- sis in Loligo pealii P. PERSON Cartilage in a Marine Polychaete Eudistylia August 4 W. E. LOVE Microheterogeneity in the Hemoglobin from Individual Sea Lampreys Y. HIRAMOTO Further Studies on the Cell Division without Mitotic Apparatus in Sea Urchin Eggs A. B. NOVIKOFF GERL, its Form and Function in Neurons of Rat Spinal Ganglia August 1 1 D. BOWNDS The Reaction of Rhodopsin and its Derivative G. WALD with Sodium Borohydride S. ZIGMAN \ Cold-Precipitable Protein in the Dogfish S. LERMAN Lens August 18 \Y. AUCLAIR On the Chromosome Number of Arbacia V. ZULLO Re-evaluation of the Late Cenozoic Cirriped, "Tamiosoma" Conrad R. PARKER Preliminary Quantitative Study of Small-Scale A. DRISCOLL Environmental and Faunal Variability J. S. NAGLE K. LUKAS REPORT OF THE DIRECTOR 41 10. MEMBERS OF THE CORPORATION, 1964 Life Members ADOLPH, DR. EDWARD F., University of Rochester, School of Medicine & Dentistry, Rochester, New York BRODIE, MR. DONALD, 522 Fifth Avenue, New York 18, New York COLE, DR. ELBERT C., 2 Chipman Park, Middlebury, Vermont COWDRY, DR. E. V., 4580 Scott Avenue, St. Louis 10, Missouri CRANE, MRS. W. MURRAY, 820 Fifth Avenue, New York 21, New York HESS, DR. WALTER, 286 North Fairview Avenue, Spartanburg, South Carolina HISAW, DR. F. L., Biological Laboratories, Harvard University, Cambridge 38, Massachusetts IRVING, LAURENCE, University of Alaska, College, Alaska JACOBS, DR. M. H., Department of Physiology, University of Pennsylvania, Phila- delphia 4, Pennsylvania LOWTHER, DR. FLORENCE, Barnard College, New York 21, New York MACDOUGALL, DR. MARY STUART, Mt. Vernon Apartments, 423 Clairmont Ave- nue, Decatur, Georgia MALONE. DR. E. F., 6610 North llth Street, Philadelphia 26, Pennsylvania MEANS. DR. J. H., 15 Chestnut Street, Boston Massachusetts MEDES, DR. GRACE, 303 Abington Avenue, Philadelphia 11, Pennsylvania MOORE, DR. J. PERCY, RD No. 1, Box 437, Chapel Hill, North Carolina PAYNE, DR. FERNANDUS, Indiana University, Bloomington, Indiana PLOUGH, DR. H. H., Amherst College, Amherst, Massachusetts PORTER, DR. H. C., University of Pennsylvania, Philadelphia 4, Pennsylvania SCOTT, DR. ERNEST L., Columbia University, New York 21, New York SCHRADER, DR. SALLY, Duke University, Durham, North Carolina TURNER, DR. C. L.. Northwestern University, Evanston, Illinois WAITE, DR. F. G., 144 Locust Street, Dover, New Hampshire WALLACE, DR. LOUISE B., 359 Lytton Avenue, Palo Alto, California WARREN, DR. HERBERT S., 2768 Egypt Road, Audubon, Pennsylvania WHEDON, DR. A. D., 21 Lawncrest, Danbury, Connecticut Regular Members ABELL, DR. RICHARD G., 55 East 2nd Avenue, New York 28, New York ADELBERG, DR. EDWARD A., Department of Microbiology, Yale University, New Haven, Connecticut 06520 ADELMAN, DR. WILLIAM J., Department of Physiology, University of Maryland Medical School, Baltimore 1 , Maryland ALBERT, DR. ALEXANDER, Mayo Clinic, Rochester, Minnesota ALLEN, DR. M. JEAN, Department of Biology, Wilson College, Chambersburg, Pennsylvania ALLEN, DR. ROBERT D., Department of Biology, Princeton University, Princeton, New Jersey 08540 ALSCHER, DR. RUTH, Department of Physiology, Manhattanville College, Purchase, New York 42 M \KINE BIOLOGIC \1. LABORATORY AMATNIEK, DR. ERNEST, 34 Horner Avenue, Hastings-on-the-Hudson, New York AMBERSON, DR. WILLIAM R., Katy Hatchs Road, Falmouth, Massachusetts ANDERSON, DR. J. M., Department of Zoology, Cornell University, Ithaca, New York ANDERSON, DR. RUBERT S., Medical Laboratories, Army Chemical Center, Mary- land ARMSTRONG, DR. PHILIP B., Department of Anatomy, State University of New York, College of Medicine, Syracuse 10, New York ARNOLD, DR. JOHN MILLER, Department of Zoology, Iowa State University, Ames, Iowa 50010 ARNOLD, DR. WILLIAM A., Division of Biology, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 ATWOOD, DR. KIMBALL C, 702 West Pennsylvania Avenue, Urbana, Illinois AUCLAIR, DR. WALTER, Department of Biological Sciences, University of Cincin- nati, Cincinnati, Ohio 45221 AUSTIN, DR. COLIN RUSSELL, Delta Regional Primate Research Center, Covington, Louisiana 70433 AUSTIN, DR. MARY L., 506Vo North Indiana Avenue, Bloomington, Indiana AYERS, DR. JOHN C., Department of Zoology, University of Michigan, Ann Arbor, Michigan BAITSELL, DR. GEORGE A., Osborn Memorial Laboratories, Yale University, New Haven, Connecticut 06520 BALL, DR. ERIC G., Department of Biological Chemistry, Harvard Medical School, Boston 15, Massachusetts BALLARD, DR. WILLIAM W., Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire BALTUS, DR. ELYANE, Laboratoire de Morphologic Animale, 1850 Chaussee de Wavre, Bruxelles 16, Belgique BANG, DR. F. B., Department of Pathobiology, The Johns Hopkins University School of Hygiene, Baltimore 5, Maryland BARD, DR. PHILLIP, The Johns Hopkins Medical School, Baltimore 5, Maryland BARTH, DR. L. G., Marine Biological Laboratory, Woods Hole, Massachusetts 02543 BARTH. DR. LUCENA, Marine Biological Laboratory, Woods Hole, Massachusetts 02543 BARTLETT, DR. JAMKS II., Department of Physics. University of Illinois, Urbana, Illinois BAUER, DR. ERIC G., Department of Anatomy, University of Minnesota, Minne- apolis, Minnesota BAYLOR, DR. E. R., Woods Hole Oceanographic Institution, Woods Hole, Massa- chusetts 02543 BAYLOR, DR. MARTHA B., Marine Biological Laboratory, Woods Hole, Massa- chusetts 02543 BEAMS, DR. HAROLD W., Department of Zoology, State University of Iowa, Iowa City, Iowa BKCK, DR. L. V., Department of Pharmacology, Indiana University, School of Ex- perimental Medicine, Bloomington, Indiana REPORT OF THE DIRECTOR 43 BEHRE, DR. ELINOR M., Black Mountain, North Carolina BELL, DR. EUGENE, Department of Biology, Massachusetts Institute of Technology, Cambridge 39, Massachusetts BENNETT, DR. MICHAEL V. L., Department of Neurology, College of Physicians & Surgeons, New York 32, New York BENNETT, DR. MIRIAM F., Department of Biology, Sweet Briar College, Sweet Briar, Virginia 24595 BERG, DR. WILLIAM E., Department of Zoology, University of California, Berkeley 4, California BERMAN, DR. MONES, National Institutes of Health, Institute of Arthritis & Metabolic Diseases, Bethesda, Maryland 20014 BERNE, DR. ROBERT M., Department of Physiology, Western Reserve University, Cleveland 6, Ohio BERNHEIMER, DR. ALAN W., New York University College of Medicine, New York, New York 10016 BERNSTEIN, DR. MAURICE, Department of Anatomy, Wayne State University College of Medicine, Detroit 7, Michigan BERTHOLF, DR. LLOYD M., Illinois Wesleyan University, Bloomington, Illinois BEVELANDER, DR. GERRIT, Dental Branch, Medical Center, University of Texas, Houston, Texas 77025 BIGELOW, DR. HENRY B., Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138 BISHOP, DR. DAVID W., Department of Embryology, Carnegie Institution of Wash- ington, 115 West University Parkway, Baltimore 10, Maryland BLANCHARD, DR. K. C., The Johns Hopkins Medical School, Baltimore 5, Mary- land BLOCK, DR. ROBERT, 518 South 42nd Street, Apt. C-7, Philadelphia 4, Pennsyl- vania BLUM, DR. HAROLD F., Department of Biology, Princeton University, Princeton, New Jersey 08540 BODANSKY, DR. OSCAR, Department of Biochemistry, Memorial Cancer Center, 444 East 68th Street, New York 21, New York BODIAN, DR. DAVID, Department of Anatomy, The Johns Hopkins University, 709 North Wolfe Street, Baltimore 5, Maryland BOELL, DR. EDGAR J., Osborn Zoological Laboratories, Yale University, New Haven, Connecticut 06520 BOETTIGER, DR. EDWARD G., Department of Zoology, University of Connecticut, Storrs, Connecticut BOLD, DR. HAROLD C., Department of Botany, University of Texas, Austin 12, Texas BOREI, DR. HANS G., Department of Zoology, University of Pennsylvania, Phila- delphia 4, Pennsylvania BOWEN, DR. VAUGHN T., Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 BRADLEY, DR. HAROLD C., 2639 Durant Avenue, Berkeley 4, California BRIDGMAN, DR. ANNA J., Department of Biology, Agnes Scott College, Decatur, Georgia 44 MARINE BIOLOGICAL LABORATORY BRINLEY, DR. F. J., JR., Department of Physiology, The Johns Hopkins Medical School, Baltimore 5, Maryland BRONK, DR. DETLEV W., The Rockefeller Institute. (>(>lh Street and York Avenue, New York 21, New York BROOKS, DR. MATILDA M., Department of Physiology, University of California, Berkeley 4, California BROWN, DR. DUGALD E. S., Department of Zoology, University of Michigan, Ann Arbor, Michigan BROWN, DR. FRANK A., JR., Department of Biological Sciences, Northwestern University, Evanston, Illinois 60201 BROWNELL, DR. KATHERINE A., Department of Physiology, Ohio State University, Columbus, Ohio BUCK, DR. JOHN B., Laboratory of Physical Biology, National Institutes of Health, Bethesda, Maryland 20014 " BULLOCK, DR. T. H., Department of Zoology, University of California, Los Angeles 24, California BURBANCK, DR. WILLIAM D., Emory University, Box 15134, Atlanta, Georgia 30333 BURDICK, DR. C. LALOR, The Lalor Foundation, 4400 Lancaster Pike, Wilmington, Delaware BURKENROAD, DR. M. D., 3169 Bremerton Place, La Jolla, California 92037 BUTLER, DR. E. G., Department of Biology, Box 704, Princeton University, Prince- ton, New Jersey 08540 CANTONI, DR. GUILLIO, National Institutes of Health, Mental Health, Bethesda, Maryland 20014 CARLSON, DR. FRANCIS D., Department of Biophysics, The Johns Hopkins Uni- versity, Baltimore, Maryland 21218 CARPENTER, DR. RUSSELL L., Tufts University, Medford 55, Massachusetts CARRIKER, DR. MELBOURNE R., Systematics-Ecology Program, Marine Biological Laboratory, Woods Hole, Massachusetts 02543 CASE, DR. JAMES, Department of Biological Sciences, University of California, Santa Barbara, California CATTELL, DR. McKEEN, Cornell University Medical College, 1300 York Avenue, New York 21, New York CHAET, DR. ALFRED B., Department of Biology, American University, Washington 16, D. C. CHAMBERS, DR. EDWARD, Department of Physiology, University of Miami Medical School, Coral Gables, Florida CHANG, DR. JOSEPH J., Inst. f. physikal. Chemie an der Techn. Hochscule, Aachen, Germany CHASE, DR. AURIN M., Department of Biology, Princeton University, Princeton, New Jersey 08540 CHENEY, DR. RALPH 11., Biological Laboratory, Brooklyn College, Brooklyn 10, New York CHILD, DR. FRANK M., Department of Zoology, University of Chicago, Chicago 37, Illinois CLAFF, DR. C. LLOYD, 5 Van Beal Road, Randolph, Massachusetts REPORT OF THE DIRECTOR 45 CLARK, DR. A. M., Department of Biological Sciences, University of Delaware, Newark, Delaware 19711 CLARK, DR. ELOISE E., Department of Zoology, Columbia University, New York, New York 10027 CLARK, DR. LEONARD B., Department of Biology, Union College, Schenectady, New York CLARKE, DR. GEORGE L., Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138 CLELAND, DR. RALPH E., Department of Botany, Indiana University, Bloomington, Indiana CLEMENT, DR. A. C., Department of Biology, Emory University, Atlanta 22, Georgia COHEN, DR. SEYMOUR S., Department of Biochemistry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania COLE, DR. KENNETH S., (NINDB), National Institutes of Health, Bethesda, Maryland 20014 COLLETTE, DR. MARY E., 34 Weston Road, Wellesley 81, Massachusetts COLLIER, DR. JACK R., Department of Biology, Rensselaer Polytech. Institute, Troy, New York COLTON, DR. H. S., Box 699, Flagstaff, Arizona COLWIN, DR. ARTHUR L., Department of Biology, Queens College, Flushing, Long Island, New York COLWIN, DR. LAURA H., Department of Biology, Queens College, Flushing, Long Island, New York COOPER, DR. KENNETH W., Department of Cytology, Dartmouth Medical School, Hanover, New Hampshire COOPERSTEIN, DR. SHERWIN J., School of Dental Medicine, University of Con- necticut, Hartford, Connecticut 06105 COPELAND, DR. MANTON, Bowdoin College, Brunswick, Maine CORNMAN, DR. IVOR, Department of Zoology, University of West Indies, Mona, Kingston, Jamaica COSTELLO, DR. DONALD P., Department of Zoology, University of North Carolina, Chapel Hill, North Carolina 27515 COSTELLO, DR. HELEN MILLER, Department of Zoology, University of North Caro- lina, Chapel Hill, North Carolina 27515 CRANE, MR. JOHN O., Woods Hole, Massachusetts 02543 CRANE, DR. ROBERT K., Department of Biochemistry, The Chicago Medical School, 2020 West Ogden Avenue, Chicago 12, Illinois CROASDALE, DR. HANNAH T., Dartmouth College, Hanover, New Hampshire CROUSE, DR. HELEN V., Institute for Molecular Biophysics, Florida State Uni- versity, Tallahassee, Florida 32306 CROWELL, DR. SEARS, Department of Zoology, Indiana University, Bloomington, Indiana CSAPO, DR. ARPAD L, The Rockefeller Institute, 66th Street and York Avenue, New York 21, New York CURTIS, DR. MAYNIE R., Box 3215, University Branch, Coral Gables 46, Florida CURTIS, DR. W. C., 504 Westmont Avenue, Columbia, Missouri 46 MARINE BIOLOGICAL LABORATORY DAIGNAULT, MR. ALEXANDER T., W. R. Grace & Company, 7 Hanover Square, New York 5, New York DAN, DR. JEAN CLARK, Misaki Biological Station, Misaki, Japan DAN, DR. KATSUMA, Misaki Biological Station, Misaki, Japan DANIELLI, DR. JAMES F., Department of Medicinal Chemistry, University of Buffalo School of Pharmacy, Buffalo 14, New York DAVIS, DR. BERNARD D., Harvard Medical School, 25 Shattuck Street, Boston 15, Massachusetts DAWSON, DR. A. B., Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138 DAWSON, DR. J. A., 129 Violet Avenue, Floral Park, Long Island, New York DEANE, DR. HELEN W., Department of Pathology, The Albert Einstein College of Medicine, New York 61, New York DETTBARN, DR. WOLF-DIETRICH, Department of Neurology, Columbia University, College of Physicians & Surgeons, New York, New York 10032 de VILLAFRANCA, DR. GEORGE W., Department of Zoology, Smith College, North- ampton, Massachusetts DILLER, DR. IRENE C, Institute for Cancer Research, Fox Chase, Philadelphia, Pennsylvania 19111 DILLER, DR. WILLIAM F., 2417 Fairhill Avenue, Glenside, Pennsylvania DODDS, DR. G. S., West Virginia University School of Medicine, Morgantown, West Virginia DOOLITTLE, DR. RUSSELL F., Department of Biology, University of California, La Jolla, California DOWBEN, DR. ROBERT, Department of Biology, Massachusetts Institute of Tech- nology, Cambridge, Massachusetts DURYEE, DR. WILLIAM R., Department of Pathology, George Washington Uni- versity School of Medicine, Washington 7, D. C. EBERT, DR. JAMES DAVID, Department of Embryology, Carnegie Institution of Washington, 115 West University Parkway, Baltimore 10, Maryland ECKERT, DR. ROGER OTTO, Department of Zoology, Syracuse University, Syracuse, New York 13210 EDDS, DR. MAC V., JR., Department of Biology, Brown University, Providence 12, Rhode Island EDER, DR. HOWARD A., The Albert Einstein College of Medicine, New York 61, New York EDWARDS, DR. CHARLES, Department of Physiology, University of Minnesota, Minneapolis 14, Minnesota EICHEL, DR. HERBERT J., Department of Biological Chemistry, Hahnemann Medi- cal College, Philadelphia, Pennsylvania ELSEN, DR. HERMAN, Department of Medicine, \Yashington University, St. Louis, Missouri ELLIOTT, DR. ALFRED M., Department of Zoology, LIniversity of Michigan, Ann Arbor, Michigan ESSNER, DR. EDWARD S., Sloan-Kettering Institute for Cancer Research, Rye, New York REPORT OF THE DIRECTOR 47 EVANS, DR. TITUS C, State University of Iowa College of Medicine, Iowa City, Iowa FAILLA, DR. PATRICIA M., Argonne National Laboratory, Radiological Physics Division, Argonne, Illinois 60440 FARMANFARMAIAN, DR. ALLAHVERDI, Professor of General Physiology, Faculty of Medicine, Pahlavi University, Shiraz, Iran FAURE-FREMIET, DR. EMMANUEL, College de France, Paris, France FAWCETT, DR. D. W., Department of Anatomy, Harvard Medical School, Boston 15, Massachusetts FERGUSON, DR. F. P., National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20014 FERGUSON, DR. JAMES K. W., Connought Laboratories, University of Toronto, Ontario, Canada FIGGE, DR. F. H. J., University of Maryland Medical School, Lombard and Green Streets, Baltimore 1, Maryland FINGERMAN, DR. MILTON, Department of Zoology, Newcomb College, Tulane University, New Orleans, Louisiana 70118 FISCHER, DR. ERNST, Department of Physiology, Medical College of Virginia, Richmond, Virginia FISHER, DR. FRANK M., JR., Department of Biology, Rice University, Houston, 1, Texas FISHER, DR. JEANNE M., Department of Biochemistry, University of Toronto, Toronto, Canada FISHER, DR. KENNETH C., Department of Biology, University of Toronto, Toronto, Canada FORBES, DR. ALEXANDER, 16 Divinity Avenue, Cambridge, Massachusetts FRAENKEL, DR. GOTTFRIED S., Department of Entomology, University of Illinois, Urbana, Illinois FREYGANG, DR. WALTER J., JR., 6247-29th Street, Washington 15, D. C. FRIES, DR. ERIK F. B., Box 605, Woods Hole, Massachusetts 02543 FUORTES, DR. MICHAEL C. F., (NINDB), National Institutes of Health, Bethesda, Maryland 20014 FURSHPAN, DR. EDWIN J., Department of Neurophysiology, Harvard Medical School, Boston 15, Massachusetts FURTH, DR. JACOB, 99 Fort Washington Avenue, New York 32, New York FYE, DR. PAUL M., Woods Hole Oceanographic Institution, Woods Hole, Massa- chusetts 02543 GABRIEL, DR. MORDECAI, Department of Biology, Brooklyn College, Brooklyn 10, New York GAFFRON, DR. HANS, Department of Biology, Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306 GALL, DR. JOSEPH G., Department of Zoology, Yale University, New Haven, Con- necticut 06520 GALTSOFF, DR. PAUL S., Bureau of Commercial Fisheries, Woods Hole, Massa- chusetts 02543 48 MARINE BIOLOGICAL LABORATORY GERMAN, DR. JAMI.S LAFAYETTE, III, Department of Pediatrics and Medicine, Cornell University Medical College, 1300 York Avenue, New York 21, New York GILBERT, DR. DANIEL L., Laboratory of Biophysics, NINDB, National Institutes of Health, Bethesda. Maryland 20014 OILMAN, DR. LAUREN C, Department of Zoology, University of Miami, Coral Gables 46, Florida GINSKHRG, DR. HAROLD S., Department of Microbiology, University of Pennsyl- vania School of Medicine, Philadelphia 4, Pennsylvania GOLDSMITH, DR. TIMOTHY H., Department of Zoology, Yale University, New Haven, Connecticut 06520 GOLDSTEIN, DR. LESTER, Department of Zoology, University of Pennsylvania, Philadelphia 4, Pennsylvania GOODCHILD, DR. CIIAUNCEY G., Department of Biology, Emory University, Atlanta 22, Georgia GOTSCHALL, DR. GERTRUDE Y., 315 Kast (>8th Street, Apt. 9-M, New York, New York 10021 GRAHAM, DR. HERBERT, U. S. Fish and Wildlife Service, Bureau of Commercial Fisheries, Woods Hole, Massachusetts 02543 GRAND, MR. C. G., Cancer Institute of Miami, 1155 N. YY. 15th Street, Miami, Florida GRANT, DR. PHILIP, National Science Foundation, 1921 Constitution Avenue, Washington 25, D. C. GRAY, DR. IRVING F., Department of Zoology, Duke University, Durham, North Carolina 27706 GREEN, DR. JAMES W., Department of Physiology, Rutgers University, New Brunswick, New Jersey 08903 GREEN. DR. JONATHAN PASCAL, Department of Biology, Brown University, Provi- dence 12, Rhode Island GREEN, DR. MAURICE, Department of Microbiology, Saint Louis University Medi- cal School, St. Louis, Missouri GREGG, DR. JAMES II., Department of Biological Sciences, University of Florida, Gainesville, Florida GREGG, DR. JOHN R., Department of Zoology. Duke University, Durham, North Carolina 27706 GREIF, DR. ROGF.R L., Department of Physiology, Cornell University Medical College, New York 21, New York GRIFFIN, DR. DONALD F., Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138 GROSCH, DR. DANIKL S., Department of Genetics, Gardner Hall, North Carolina State College, Raleigh, North Carolina GROSS, DR. PAUL, Department of Biology, Brown University, Providence 12, Rhode Island GRUNDFEST, DR. HAKKY, Department of Neurology. Columbia University College of Physicians & Surgeons, New York 32, NYw York Gi [THAN, DR. RITA, Department of Biology, Brooklyn College, Brooklyn 10, Xew York REPORT OF THE DIRECTOR 49 GWILLIAM, DR. G. F., Department of Biology, Reed College, Portland, Oregon 97202 HAJDU, DR. STEPHEN, National Institutes of Health, Bethesda, Maryland 20014 HALL, DR. FRANK G., Department of Physiology, Duke University Medical School, Durham, North Carolina 27706 HALVORSEN, DR. HARLYN O., Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706 HAMBURGER, DR. VIKTOR, Department of Zoology, Washington University, St. Louis, Missouri 63130 HAMILTON, DR. HOWARD L.. Department of Biology, University of Virginia, Charlottesville, Virginia HANCE, DR. ROBERT T., RR No. 3, 6609 Smith Road, Loveland, Ohio HARDING, DR. CLIFFORD V., JR., Oakland University, Rochester, Michigan HARNLY, DR. MORRIS H., Washington Square College, New York University, New York 3, New York HARTLINE, DR. H. KEFFER, The Rockefeller Institute, 66th Street and York Ave- nue, New York 21, New York HARTMAN, DR. FRANK A., Ohio State University, Hamilton Hall, Columbus, Ohio HARTMAN, DR. P. E., Department of Biology, The Johns Hopkins University, Baltimore 18, Maryland HARVEY, DR. ETHEL BROWNE, Marine Biological Laboratory, Woods Hole, Massa- chusetts 02543 HASTINGS, DR. J. WOODLAND, Department of Biochemistry, University of Illi- nois, Urbana, Illinois HAUSCHKA, DR. T. S., Roswell Park Memorial Institute, 666 Elm Street, Buffalo 3, New York HAXO, DR. FRANCIS T., Division of Marine Botany, Scripps Institution of Oceanography, University of California, La Jolla, California HAYASHI, DR. TERU, Department of Zoology, Columbia University, New York, New York 10027 HAYDEN, DR. MARGARET A., 34 Weston Road, Wellesley 81, Massachusetts HAYWOOD, DR. CHARLOTTE, Box 14, South Hadley, Massachusetts HENDLEY, DR. CHARLES D., 615 South Avenue, Highland Park, New Jersey HENLEY, DR. CATHERINE, Department of Zoology, University of North Carolina, Chapel Hill, North Carolina 27515 HERNDON, DR. WALTER R., Office of the Dean, University of Tennessee, Knoxville, Tennessee HERVEY, MR. JOHN P., Box 735, Woods Hole, Massachusetts 02543 HESSLER, DR. ANITA Y., Marine Biological Laboratory. Woods Hole, Massa- chusetts 02543 Hi ATT, DR. HOWARD H., Department of Medicine, Harvard Medical School, Boston 15, Massachusetts HIBBARD, DR. HOPE, Department of Zoology, Oberlin College, Oberlin, Ohio HIRSHFIELD, DR. HENRY I., Department of Biology. Washington Square Center, New York University, New York 3, New York HOADLEY, DR. LEIGH, Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138 50 MARINE BIOLOGICAL LABORATORY HODES, DR. ROBERT, Department of Pediatrics, The Mount Sinai Hospital, New York 29, New York HODGES, DR. CHARLES, IV, Department of Biology, Temple University, Phila- delphia 22, Pennsylvania HOFFMAN, DR. JOSEPH, National Heart Institute, National Institutes of Health, Bethesda, Maryland 20014 IIoi.i.AKXDER, DR. ALEXANDER, Biology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 Ilor.z, DR. GEORGE G., JR., Department of Microbiology, State University of New York, Upstate Medical College, Syracuse, New York 13210 HOPKINS, DR. HOYT S., 59 Heatherdell Road, Ardsley, New York HOSKIN, DR. FRANCIS C. G., Department of Neurology, Columbia University, College of Physicians & Surgeons, New York 32, New York HUNTER, DR. FRANCIS R., University of the Andes, Calle IS-a, Carrera 1-E, Bogota, Colombia, South America HUNTER, DR. W. D. RUSSELL, Department of Zoology, 110 Lyman Hall, Syracuse University, Syracuse, New York 13210 HURWITZ, DR. J., Department of Molecular Biology, The Albert Einstein College of Medicine, New York 61, New York HUTCH ENS, DR. JOHN E., Department of Physiology, University of Chicago, Chicago 37, Illinois HYDE, DR. BEAL B., Department of Botany, University of Texas, Austin, Texas 78703 HYMAN, DR. LIBBIE H., American Museum of Natural History, Central Park West at 79th Street, New York 24, New York INOUE, DR. SHINYA, Department of Cytology, Dartmouth Medical School, Hanover, New Hampshire ISENBERG, DR. IRVIN, Institute for Muscle Research, Marine Biological Laboratory, Woods Hole, Massachusetts 02543 ISELIN, MR. COLUMBUS O'D., Woods Hole, Massachusetts 02543 ISSELBACKER, DR. KURT J., Massachusetts General Hospital, Boston, Massachusetts JANOFF, DR. AARON, Department of Pathology, New York University School of Medicine, 550 First Avenue, New York, New York 10016 TENNER, DR. CHARLES E., Department of Zoology, University of North Carolina, Chapel Hill, North Carolina 27515 JOHNSON, DR. FRANK IT.. Department of Biology, Princeton University, Princeton, New Jersey 08540 JONES, DR. E. RUFEIN, JR., Department of Biological Sciences, University of Florida, Gainesville, Florida JONES, DR. RAYMOND F., Department of Biology, State University of New York, Stony Brook, Long Island, New York 11733 JOSEPHSOX, DR. R. K., Department of Zoology, University of Minnesota, Minne- apolis 14, Minnesota KAAN, DR. HELEN W., Marine Biological Laboratory, Woods Hole, Massachusetts 02543 KARAT, DR. E. A., Neurological Institute, Columbia University, College of Phy- sicians & Surgeons, New York 32, New York REPORT OF THE DIRECTOR 51 KALEY, DR. GABOR, Department of Pathology, New York University School of Medicine, 550 First Avenue, New York, New York 10016 KAMINER, DR. BENJAMIN, Institute for Muscle Research, Marine Biological Laboratory, Woods Hole, Massachusetts 02543 KANE, DR. ROBERT E., Department of Cytology, Dartmouth Medical School, Han- over, New Hampshire KARUSH, DR. FRED, Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia 4, Pennsylvania KAUFMANN, DR. B. P., Department of Zoology, University of Michigan, Ann Arbor, Michigan KEMP, DR. NORMAN E., Department of Zoology, University of Michigan, Ann Arbor, Michigan KEMPTON, DR. RUDOLF T., Department of Zoology, Vassar College, Poughkeepsie, New York KEOSIAN, DR. JOHN, Department of Biology, Rutgers University, Newark 2, New Jersey KETCHUM, DR. BOSTWICK H., Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 KEYNAN, DR. ALEXANDER, Institute for Biological Research, Ness Ziona, Israel KILLE, DR. FRANK R., State Department of Education, Albany 1, New York KIND, DR. C. ALBERT, Department of Zoology, University of Connecticut, Storrs, Connecticut KINDRED, DR. J. E., Box 1873, University of Virginia, Charlottesville, Virginia KING, DR. ROBERT L., State University of Iowa, Iowa City, Iowa KINGSBURY, DR. JOHN M., Department of Botany, Cornell University, Ithaca, New York KINNE, DR. OTTO, Director, Biologische Anstalt Helgoland, 2 Hamburg-Altona, Palmaille 9, Germany KISCH, DR. BRUNO, 71 Maple Street, Brooklyn 25, New York KLEIN, DR. MORTON, Department of Microbiology, Temple University, Phila- delphia, Pennsylvania KLEINHOLZ, DR. LEWIS Ii., Department of Biology, Reed College, Portland, Ore- gon 97202 KLOTZ, DR. I. M., Department of Chemistry, Northwestern University, Evanston, Illinois 60201 KOLIN, DR. ALEXANDER, Department of Biophysics, University of California Medi- cal School, Los Angeles 24, California KORR, DR. I. M., Department of Physiology, Kirksville College of Osteopathy, Kirksville, Missouri KRAHL, DR. M. E., Department of Physiology, University of Chicago, Chicago 37, Illinois KRANE, DR. STEPHEN M., Massachusetts General Hospital, Boston 14, Massa- chusetts KRASSNER, DR. STUART MITCHELL, The Rockefeller Institute, New York 21, New York KRAUSS, DR. ROBERT, Department of Botany, University of Maryland, College Park, Maryland 52 MARINE I'.lol OGICAL I. VBOR VTORY KKKIG, DR. WENDELL I. S., 303 East Chicago Avenue, Chicago, Illinois Kui-n.LR, I)u. STEPHEN \\'., Department of I'hannacology, Neurophysiological Laboratory, Harvard Medical School, Boston 15, Massachusetts Ki'NiTZ, DR. MOSKS, The Rockefeller Institute, 6(>th Street and York Avenue, New York 21, New York LAMY, DR. FRANCOIS, Department of Anatomy, University of Pittsburgh School of Medicine, Pittsburgh 1.3, Pennsylvania LANCEFIELD, DR. D. E., (Jueens College, Flushing, New York LANCEFIELD, DR. REBECCA C., The Rockefeller Institute, 66th Street and York Avenue, New York 21, New York LANDIS, DR. E. M., Harvard Medical School, Boston 15, Massachusetts LANSING, DR. ALBERT I., Department of Anatomy, University of Pittsburgh School of Medicine, Pittsburgh 13, Pennsylvania LASH, DR. JAMES W., Department of Anatomy, University of Pennsylvania School of Medicine, Philadelphia 4, Pennsylvania LAI FKR, DR. JlAxs, Department of Biology, The Johns Hopkins University, Balti- more, Maryland 21218 LAUFFER, DR. MAX A., Department of Biophysics, University of Pittsburgh, Pitts- burgh 13, Pennsylvania LAWLER, DR. H. CLAIRE, Department of Biochemistry and Neurology, Columbia University, College of Physicians & Surgeons, New York 32, New York LAVIN, DR. GEORGE I., 6200 Norvo Road, Baltimore 7, Maryland LAZAROW, DR. ARNOLD, Department of Anatomy, University of Minnesota School of Medicine, Minneapolis 14, Minnesota LEDERBERG, DR. JOSHUA, Department of Genetics, Stanford Medical School, Palo Alto, California LEE, DR. RICHARD E., Cornell University College of Medicine, New York 21, New York LEFEVRE, DR. PAUL G., University of Louisville School of Medicine, Louisville, Kentucky i,i ii MANN, DR. FRITZ, /oologi.schc Institut, University of Berne, Berne, Switzer- land I.KVINE, DR. RACIIMIEL. Department of Medicine, New York Medical School, 5th Avenue and 106th Street, New York 29, New York LEVY, DR. MILTON, Department of Biochemistry, New York University School of Dentistry, New York 10, New York LEWIN, I )R. RALPH A., Scripps Institution of Oceanography, La Jolla, California Li \vis, I )R. IIi.k.MAN WILLIAM, Genetic Biology Program, National Science Foundation, Washington 25, D. C. LING, DR. GlLBi UT, 307 Berkeley l\oad, Merion, Pennsylvania LITTLE, DR. E. P., 21<> Highland Street, West Newton, Massachusetts LLOYD, DR. DAVID P. ('., The Rockefeller Institute, (><>th Street and York Avenue, New York 21, New York LoCHHEAD, DR. JOHN II., Department of /oology. University of Vermont, Burling- ton, Vermont Loi B, DR. R. F., 950 Park Avenue, New York 2S. New York REPORT OF THE DIRECTOR LOEWENSTEIN, DR. WERNER R., Department of Physiology, Columbia University, College of Physicians & Surgeons, New York 32, New York LOFTFIELD, DR. ROBERT B., Massachusetts General Hospital, Boston 14, Massa- chusetts LONDON, DR. IRVING M., Department of Medicine, The Albert Einstein College of Medicine, New York 61, New York LORAND, DR. LASZLO, Department of Chemistry, Northwestern University, Evans- ton, Illinois 60201 DE LORENZO, DR. ANTHONY, Anatomical and Pathological Research Laboratories, The Johns Hopkins Hospital, Baltimore 5, Maryland LOVE, DR. WARNER E., 1043 Marlau Drive, Baltimore 12, Maryland LUBIN, DR. MARTIN, Department of Pharmacology, Harvard Medical School, Boston 15, Massachusetts LYNCH, DR. CLARA J., The Rockefeller Institute, 66th Street and York Avenue, New York 21, New York LYNN, DR. W. GARDNER, Department of Biology, Catholic University of America, Washington 17, D. C. MAAS, DR. WERNER K., New York University College of Medicine, New York, New York 10016 MAGRUDER, DR. SAMUEL R., Department of Anatomy, Tufts Medical School, 136 Harrison Avenue, Boston, Massachusetts MAHLER, DR. HENRY R., Department of Biochemistry, Indiana University, Bloom- ington, Indiana MANWELL, DR. REGINALD D., Department of Zoology, Syracuse University, Syra- cuse, New York 13210 MARKS, DR. PAUL A., Presbyterian Hospital, Columbia University, College of Physicians & Surgeons, New York 32, New York MARSHAK, DR. ALFRED, Tulane University Medical School, New Orleans, Louisi- ana MARSLAND, DR. DOUGLAS A v 48 Church Street, Woods Hole, Massachusetts 02543 MARTIN, DR. EARL A., 682 Rudder Road, Naples, Florida 33940 MATHEWS, DR. SAMUEL A., Thompson Biological Laboratory, Williams College, Williamstown, Massachusetts MAZIA, DR. DANIEL, Department of Zoology, University of California, Berkeley 4, California McCANN, DR. FRANCES, Department of Physiology, Dartmouth Medical School, Hanover, New Hampshire McCoucH, DR. MARGARET SUMWALT, University of Pennsylvania Medical School, Philadelphia 4, Pennsylvania McDoNALD, SISTER ELIZABETH SETON, Department of Biology, College of Mount St. Joseph, Mt. St. Joseph, Ohio MCDONALD, DR. MARGARET R., Waldemar Medical Research Foundation, Sunny- side Boulevard and Waldemar Road, Woodbury, Long Island, New York MCELROY, DR. WILLIAM D., Department of Biology, The Johns Hopkins Uni- versity, Baltimore, Maryland 21218 54 MARINE BIOLOGICAL LABORATORY MEINKOTH, DR. NORMAN A., Department of Biology, Swarthmore College, Swarthmore, Pennsylvania METZ, DR. CHARLES B., Institute of Molecular Evolution, School of Environ- mental and Planetary Sciences, University of Miami, Coral Gables 46, Florida METZ, DR. CHARLES W., P.ox 714, Woods Hole, Massachusetts 02543 MIDDLEBROOK, DR. ROBERT, Department of Physiology, Dartmouth Medical Center, Hanover, New Hampshire MILKMAN, DR. ROGER D., Department of Zoology, Syracuse University, Syracuse, New York 13210 MILLER, DR. J. A., |R., Department of Anatomy, Tulane University Medical School, New Orleans 18, Louisiana MILXE, DR. LORUS, J., Department of Zoology, University of New Hampshire, Durham, New Hampshire 03824 MOE, MR. HENRY A., Guggenheim Memorial Foundation, 551 Fifth Avenue, New York 17, New York MONROY, DR. ALBERTO, Institute of Comparative Anatomy, University of Palermo, Palermo, Italy MOORE, DR. GEORGE M., Department of Zoology, University of New Hampshire, Durham, New Hampshire 03824 MOORE, DR. JOHN A., Department of Zoology, Columbia University, 954 Schermer- horn, New York, New York 10027 MOORE, DR. JOHN W., Department of Physiology and Pharmacology, Duke Uni- versity Medical School, Durham, North Carolina 27706 MOORE, DR. R. O., Department of Biochemistry, Ohio State University, Columbus 10, Ohio MORAN, DR. JOSEPH F., JR., Department of Biology, Russell Sage College, Troy, New York MORRILL, DR. JOHN B., JR., Department of Biology, Wesleyan University, Middle- town, Connecticut 06457 MOSCONA, DR. A. A., Department of Zoology, University of Chicago, Chicago 37, Illinois MOUL, DR. E. T., Department of Botany, Rutgers University, New Brunswick, New Jersey 08903 MOUNTAIN, MRS. J. D., Charles Road, Mount Kisco, New York MULLINS, DR. LORIN J., Department of Biophysics, University of Maryland School of Medicine, Baltimore 1, Maryland MCSACCHIA, DR. XAVIER J., Department of Biology, Saint Louis University, St. Louis 4, Missouri NABRIT, DR. S. M., President, Texas Southern University, 3201 Wheeler Avenue, Houston 4, Texas XACE, DR. PAUL FOLEY, Department of Biology, Hamilton College, McMaster University, Hamilton, Ontario, Canada NACHMANSOIIN, DR. DAVID, Department of Neurology, Columbia University, College of Physicians & Surgeons, New York 32, New York NASATIR, DR. MAIMON, Department of P.otany. Brown University, Providence 12, Rhode Island REPORT OF THE DIRECTOR 55 NASON, DR. ALVIN, McCollum-Pratt Institute, The Johns Hopkins University, Baltimore, Maryland 21218 NAVEZ, DR. ALBERT E., 206 Churchill's Lane, Milton 86, Massachusetts NELSON, DR. LEONARD, Department of Physiology, Emory University, Atlanta 22, Georgia NEURATH, DR. H., Department of Biochemistry, University of Washington, Seattle 5, Washington NICOLL, DR. PAUL A., Black Oak Lodge, RR No. 2, Bloomington, Indiana Niu, DR. MAN-CHIANG, Temple University, Philadelphia 22, Pennsylvania NOVIKOFF, DR. ALEX B., Department of Pathology, The Albert Einstein College of Medicine, New York 61, New York OCHOA, DR. SEVERO. New York University College of Medicine, New York, New York 10016 ODUM, DR. EUGENE, Department of Zoology. University of Georgia, Athens, Georgia OPPENHEIMER, DR. JANE M., Department of Biology, Bryn Mawr College, Bryn Mawr, Pennsylvania OSTERHOUT, DR. MARIAN IRWIN, 456 East 63rd Street, New York 21, New York PACKARD, DR. CHARLES, Woods Hole, Massachusetts 02543 PAGE, DR. IRVINE H., Cleveland Clinic, Cleveland, Ohio PALMER, DR. JOHN D., Department of Biology, New York University, University Heights, New York 53, New York PARPART, DR. ARTHUR K., Department of Biology, Princeton University, Prince- ton, New Jersey 08540 PASSANO, DR. LEONARD M., Department of Zoology, University of Wisconsin, Madison, Wisconsin 53706 PATTEN, DR. BRADLEY M., University of Michigan School of Medicine, Ann Arbor, Michigan PERKINS, DR. JOHN F., JR., Department of Physiology, University of Chicago, Chicago 37, Illinois PERSON, DR. PHILIP, Chief, VA Hospital Special Dental Research Program. Brooklyn 9, New York PETTIBONE, DR. MARIAN H., Division of Invertebrate Zoology, U. S. National Museum, Washington 25, D. C. PHILPOTT, DR. DELBERT E., Department of Biochemistry, University of Colorado Medical Center, 4200 East Ninth Avenue, Denver 20. Colorado PICK, DR. JOSEPH, Department of Anatomy, New York University-Bellevue Medi- cal Center, New York. New York 10016 PIERCE, DR. MADELENE E., Department of Zoology, Vassar College, Poughkeepsie, New York POLLISTER, DR. A. W., Department of Zoology, Columbia University, New York, New York 10027 POND, DR. SAMUEL E., 53 Alexander Street, Manchester, Connecticut POTTER, DR. DAVID, Department of Neurophysiology, Harvard Medical School, Boston 15, Massachusetts PORTER, DR. KEITH R., Biological Laboratories, Harvard University, Cambridge, Massachusetts 02 138 56 MARINE I'.IOLOGKAI. LABORATORY PROCTOR, DR. NATHANIEL, Department of Biology, Morgan State College, Balti- more 12, Maryland PROSSER, DR. C. LADD, Department of Physiology, Burrill Hall, University of Illinois, Urbana, Illinois PROVASOLI, DR. Lric.i. llaskins Lai (oratories, 305 East 43rd Street, New York 17, New York RAMSEY, DR. ROBERT W., Medical College of Virginia, Richmond, Virginia RAXKIX, DR. JOHN S., Department of Zoology, University of Connecticut, Storrs, Connecticut RANZI, DR. SILVIO, Department of Zoology, University of Milan, Milan, Italy RAPPORT, DR. M., Department of Biochemistry, The Albert Einstein College of Medicine, New York 61, New York RATNER, DR. SARAH, Public Health Research Institute of the City of New York, Foot of East 15th Street, New York 9, New York RAY, DR. CHARLES, JR., Department of Biology, Emory University, Atlanta 22, Georgia READ, DR. CLARK P., Department of Biology, Rice University, Houston 1, Texas REBHUN. DR. LIONEL L, Department of Biology, Princeton University, Princeton, New Jersey 08540 RECHNAGEL, DR. R. O., Department of Physiology, Western Reserve University, Cleveland 6, Ohio REDFIELD, DR. ALFRED C., \Voods Hole, Massachusetts 02543 RF.NN, DR. CHARLES E., The Johns Hopkins University, 509 Ames Hall, Balti- more, Maryland 21 2 18 REUBEN, DR. JOHN P., Department of Neurology, Columbia University, College of Physicians & Surgeons, New York 32, New York REZNIKOFF, DR. PAUL, Cornell University Medical College, 1300 York Avenue New York 16. New York RICH, DR. ALEXANDER, Department of Biology, Massachusetts Institute of Tech- nology, Cambridge, Massachusetts RICHARDS, DR. A., 2950 East Mabel Street, Tucson, Arizona RICHARDS, DR. A. GLENN. Department of Entomology, University of Minnesota, St. Paul, Minnesota 55101 RICHARDS, DR. OSCAR \Y., Research Center, American Optical Company, South- bridge, Massachusetts ROCKSTEIN, DR. MORRIS, Medical Research Building, 1600 N. W. 10th Avenue, Miami 36, Florida K'OMKK, DR. ALFRED S., Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138 koXKiN, DR. RAPHAEL R., Department of Biological Sciences, University of Dela- ware, Newark, Delaware 19711 ROOT, DR. l\. \Y., Department of Biology, College of the City of New York, New York, New York ROOT, DR. \Y. S., Department of Physiology, Columbia I "iiiversily. College of Physicians & Surgeons, New York 32, New York l\osi . DR. S. MKRYL, Department of Anatomy, Tulanc I'liivcrsity, New Orleans, Louisiana REPORT OF THE DIRECTOR ROSENBERG, DR. EVELYN K., Department of Pathology, New York University- Bellevue Medical Center, New York, New York 10016 ROSENBERG, DR. PHILIP, Department of Neurology, Columbia University, New York 32, New York ROSENBLUTH, Miss RAJA, Marine Biological Laboratory, Woods Hole, Massa- chusetts 02543 ROSENKRANZ, DR. HERBERT S., Department of Microbiology, Columbia University, New York 32, New York ROSENTHAL, DR. THEODORE B., Department of Anatomy, University of Pittsburgh School of Medicine, Pittsburgh 13, Pennsylvania ROSLANSKY, DR. JOHN, Marine Biological Laboratory, Woods Hole, Massachusetts 02543 ROTH, DR. JAY S., Department of Zoology and Entomology, University of Con- necticut, Storrs, Connecticut ROTHENBERG, DR. M. A., Scientific Director, Dug way Proving Ground, Dugway, Utah RUGH, DR. ROBERTS, Radiological Research Laboratory, Columbia University, College of Physicians & Surgeons, New York 32, New York RUNNSTROM, DR. JOHN, Wenner-Grens Institute, Stockholm, Sweden RUSTAD, DR. RONALD C., Department of Radiology, Western Reserve University, Cleveland 6, Ohio RUTMAN, DR. ROBERT J., General Laboratory Building, 215 South 34th Street, Philadelphia, Pennsylvania RYTHER, DR. JOHN H., Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 SAGER, DR. RUTH, Department of Zoology, Columbia University, New York, New York 10027 SANBORN, DR. RICHARD C., Department of Biological Sciences, Purdue University, Lafayette, Indiana 47907 SANDERS, DR. HOWARD L., Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 SATO, DR. HIDEMI, Department of Cytology, Dartmouth Medical School, Hanover, New Hampshire SAUNDERS, DR. JOHN, Department of Biology, Marquette University, Milwaukee 3, Wisconsin SAUNDERS, MR. LAWRENCE, West Washington Square, Philadelphia 5, Pennsyl- vania SAZ, DR. ARTHUR KENNETH, National Institutes of Health, Bethesda 14, Maryland SCHACHMAN, DR. HOWARD K., Department of Biochemistry, University of Cali- fornia, Berkeley 4, California SCHARRER, DR. ERNST A., Department of Anatomy, The Albert Einstein College of Medicine, New York 61, New York SCHLESINGER, DR. R. WALTER, Department of Microbiology, Rutgers Medical School, New Brunswick, New Jersey SCHMIDT, DR. L. H., National Primate Center, University of California, Davis, California M \K1.\K IMOLOGICAL LABORATORY Sen MITT, DR. FRANCIS O., Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts SCHMITT, DR. O. H., Department of Physics, University of Minnesota, Minne- apolis 14, Minnesota SCHNEIDERMAN, DR. HOWARD A., Department of Biology, Western Reserve Uni- versity, Cleveland 6, Ohio SCHOLANDER, DR. P. F., Scripps Institution of Oceanography, La Jolla, California SCHOTTE, DR. OSCAR E., Department of Biology, Amherst College, Amherst, Massachusetts SCHRAMM, DR. J. R., Department of Botany, Indiana University, Bloomington, Indiana SCHUEL, DR. HERBERT, Department of Chemistry, Northwestern University, Evans- ton, Illinois SCOTT, DR. ALLAN C., Colby College, Waterville, Maine SCOTT, DR. D. B. McNAiR, Lippincott Building, 25th and Locust Streets, Phila- delphia, Pennsylvania 19103 SCOTT, SISTER FLORENCE MARIE, Seton Hill College, Greensburg, Pennsylvania SCOTT, DR. GEORGE T., Department of Biology, Oberlin College, Oberlin, Ohio SEARS, DR. MARY, Glendon Road, Woods Hole, Massachusetts 02543 SELIGER, DR. HOWARD H., McCollum-Pratt Institute, The Johns Hopkins Univer- sity, Baltimore, Maryland 21218 SENFT, DR. ALFRED W., Marine Biological Laboratory, Woods Hole, Massachu- setts 02543 SEVERINGHAUS, DR. AURA E., 375 West 250th Street, New York 71, New York SHAPIRO, DR. HERBERT, 6025 North 13th Street, Philadelphia 41, Pennsylvania SHAVER, DR. JOHN R., Department of Zoology, Michigan State University, East Lansing, Michigan SHEDLOVSKY, DR. THEODORE, The Rockefeller Institute, 66th Street and York Avenue, New York 21, New York SHEMIN, DR. DAVID, Department of Biochemistry, Columbia University, New York, New York 10027 SHERMAN, DR. I. W., Division of Life Sciences, University of California, River- side, California 92502 SICHEL, DR. FERDINAND J. M., University of Vermont, Burlington, Vermont SICHEL, MRS. FERDINAND, Department of Biology, Trinity College, Burlington, Vermont SILVA, DR. PAUL, Department of Botany, University of California, Berkeley 4, California SIMMONS, DR. JOHN E., JR., Department of Biology, Rice University, Houston 1, Texas SLIFER, DR. ELEANOR H., 308 Lismore Avenue, Glenside, Pennsylvania SLOBODKIN, DR. LAWRENCE BASIL, Department of Zoology, University of Michi- gan, Ann Arbor, Michigan SMKLSER, DR. GEORGE K., Department of Anatomy, Columbia University, New York, New York SMITH, DR. DIETRICH C., Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland REPORT OF THE DIRECTOR 59 SMITH, MR. HOMER P., General Manager, Marine Biological Laboratory, Woods Hole, Massachusetts 02543 SMITH, MR. PAUL FERRIS, Marine Biological Laboratory, Woods Hole, Massa- chusetts 02543 SMITH, DR. RALPH I., Department of Zoology, University of California, Berkeley 4, California SONNEBORN, DR. T. M., Department of Zoology, Indiana University, Bloomington, Indiana SONNENBLICK, DR. B. P., Rutgers University, 40 Rector Street, Newark 2, New Jersey SPECTOR, DR. A., Howe Laboratories, Harvard Medical School, Boston 15, Massa- chusetts SPEIDEL, DR. CARL C., Department of Biology, Randolph-Macon Woman's College, Lynchburg, Virginia SPIEGEL, DR. MELVIN, Division of Biology, California Institute of Technology, Pasadena, California 91109 SPINDEL, DR. WILLIAM, Department of Chemistry, Yeshiva University, Belfer Graduate School, Amsterdam Avenue and 186th Street, New York, New York SPIRTES, DR. MORRIS ALBERT, Department of Pharmacology, Hahnemann Medical College, Philadelphia, Pennsylvania S PRATT, DR. NELSON T., Department of Zoology, University of Minnesota, Minne- apolis 14, Minnesota SPYROPOULOS, DR. C. S., Building 9, Room 140, National Institutes of Health, Bethesda, Maryland 20014 STARR, DR. RICHARD C., Department of Botany, Indiana University, Bloomington, Indiana STEINBACH, DR. H. BURR, Department of Zoology, University of Chicago, Chicago 37, Illinois STEINBERG, DR. MALCOLM S., Department of Biology, The Johns Hopkins Uni- versity, Baltimore, Maryland 21218 STEINHARDT, DR. JACINTO, Georgetown University, Washington 7, D. C. STEPHENS, DR. GROVER C., Department of Biological Sciences, University of Cali- fornia, Irvine, California 92650 STETTEN, DR. DE\YITT, JR., Rutgers University Medical School, New Brunswick, New Jersey STETTEN, DR. MARJORIE R., Rutgers University Medical School, New Brunswick, New Jersey STEWART, DR. DOROTHY, Rockford College, Rockford, Illinois STOREY, DR. ALMA G., Department of Botany, Mount Holyoke College, South Hadley, Massachusetts STONE, DR. WILLIAM, JR., Ophthalmic Plastics Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts STRAUSS, DR. W. L., JR., Department of Anatomy, The Johns Hopkins University Medical School, Baltimore 5, Maryland STREHLER, DR. BERNARD L., 4115 West View Road. Baltimore 18, Maryland STRITTMATTER, DR. PHILIPP, Department of Biological Chemistry, Washington University School of Medicine, St. Louis, Missouri 60 MARINE BIOLOGICAL LABORATORY STUNKAKD, DR. HORACE \V., American Museum of Natural History, Central Park West at 79th Street, New York 24, New York STURTEYANT, DR. AT.FRF.D H., California Institute of Technology, Pasadena, Cali- fornia 9 1109 SUDAK, DR. FREDERICK N., Department of Physiology, The Albert Einstein Col- lege of Medicine, New York 61, New York SULKIN, DR. S. EDWARD, Department of Bacteriology, University of Texas, Southwestern Medical School, Dallas, Texas SrssMAN, DR. MAURICE, Department of Biology, Brandeis University, Waltham, Massachusetts SWANSON, DR. CARL PONTIUS, Department of Biology, The Johns Hopkins Uni- versity, Baltimore, Maryland 21218 SWOPE. MR. GERARD. JR., 570 Lexington Avenue, New York 22, New York SZABO, DR. GEORGE, Department of Dermatology, Massachusetts General Hospital, Boston 14, Massachusetts SzENT-Gy<">RCYi, DR. ALBERT, Institute for Muscle Research, Marine Biological Laboratory, Woods Hole, Massachusetts 02543 SZENT-GYORGYI, DR. ANDREW G., Department of Cytology, Dartmouth Medical School, Hanover, New Hampshire TASAKI, DR. ICHIJI, Laboratory of Neurobiology (NIMH), National Institutes of Health, Bethesda, Maryland 20014 TAYLOR, DR. ROBERT E., Laboratory of Neurophysiology (NINDB), National Institutes of Health, Bethesda, Maryland 20014 TAYLOR, DR. WILLIAM RANDOLPH, Department of Botany, University of Michigan, Ann Arbor, Michigan TAYLOR, DR. W. ROWLAND, Department of Oceanography, The Johns Hopkins University, Baltimore, Maryland 21218 TEWINKEL, DR. Lois E., Department of Zoology, Smith College, Northampton, Massachusetts TRACY, DR. HENRY C., 3595 Mynders No. 3, Memphis, Tennessee TRACER, DR. WILLIAM, The Rockefeller Institute, 66th Street and York Avenue, New York 21, New York TRAVIS, DR. D. M., Department of Pharmacology, University of Florida, Gaines- ville, Florida TRINKAUS, DR. J. PHILIP, Department of Zoology, Osborn Zoological Labora- tories, Yale University, New Haven, Connecticut 06520 TROLL, DR. WALTER, Department of Industrial Medicine, New York University College of Medicine, New York 16, New York TWEEDELL, DR. KENYON S., Department of Biology, University of Notre Dame, Notre Dame, Indiana TYLER, DR. ALBERT, Division of Biology, California Institute of Technology, Pasa- dena, California 91109 URETZ, DR. l\or.i irr B., Department of Biophysics, University of Chicago, Chicago, Illinois VAX llot.Di, DR. KENSAI. EDWARD, Department of Chemistry, University of Illi- nois, Urbana, Illinois VILLEE, DR. CLAUDE A., Department of Biological Chemistry, Harvard Medical School, Boston 15, Massachusetts REPORT OF THE DIRECTOR 61 VINCENT, DR. WALTER S., Department of Anatomy, University of Pittsburgh, Pittsburgh 13, Pennsylvania WAINIO, DR. W. W., Bureau of Biological Research, Rutgers University, New Brunswick, New Jersey 08903 WALD, DR. GEORGE, Biological Laboratories, Harvard University, Cambridge. Massachusetts 02138 WARNER, DR. ROBERT C.. Department of Chemistry, New York University College of Medicine. New York, New York 10016 WARREN, DR. LEONARD, Research Medical Officer, National Institutes of Health, Bethesda, Maryland 20014 WATERMAN, DR. T. H., Department of Zoology, 272 Gibbs Research Laboratory. Yale University, New Haven, Connecticut 06520 WATSON, DR. STANLEY WILLARD, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543 WEBB, DR. MARGUERITE, Department of Physiology, Goucher College, Towson, Baltimore 4, Maryland WEISS, DR. LEON PAUL, Department of Anatomy, The Johns Hopkins Medical School, Baltimore 19, Maryland WEISS, DR. PAUL A., Laboratory of Developmental Biology, The Rockefeller Insti- tute, 66th Street and York Avenue, New York 21, New York WENRICH, DR. D. H., Department of Zoology, University of Pennsylvania, Phila- delphia 4, Pennsylvania WERMAN, DR. ROBERT, Institute of Psychiatric Research, Indiana University Medi- cal Center, 1100 West Michigan Street, Indianapolis 7, Indiana WHITAKER, DR. DOUGLAS M., 320 Good Hill Road, Kentfield, California WHITE, DR. E. GRACE, 1312 Edgar Avenue, Chambersburg, Pennsylvania WHITING, DR. ANNA R., 535 West Vanderbilt Drive, Oak Ridge, Tennessee WHITING, DR. PHINEAS, 535 West Vanderbilt Drive, Oak Ridge, Tennessee WICHTERMAN, DR. RALPH, Department of Biology. Temple University, Phila- delphia 22, Pennsylvania WICKERSHAM, MR. JAMES H., 791 Park Avenue, New York 21, New York WIERCINSKI, DR. FLOYD ]., Chicago Teachers College North, 5500 North St. Louis Avenue, Chicago 25, Illinois WIGLEY, DR. ROLAND L., U. S. Fish and Wildlife Service, Woods Hole, Massa- chusetts 02543 WILBER, DR. C. G., Director, Marine Laboratory, University of Delaware, New- ark, Delaware 19711 WILLIER, DR. B. H., Department of Biology, The Johns Hopkins University, Balti- more, Maryland 21218 WILSON, DR. I. WALTER, Department of Biology, Brown University, Providence 12, Rhode Island WILSON, DR. T. HASTINGS, Department of Physiology, Harvard Medical School, Boston 15, Massachusetts WILSON, DR. WALTER L., Department of Biology, Oakland I'niversity. Rochester, Michigan WINTERS, DR. ROBERT WAYNE, Department of Pediatrics, Columbia University. College of Physicians & Surgeons, New York 32, New York 62 MARINE BIOLOGICAL LABORATORY \YiTSc-in, DR. EMIL, Universitat Basel, Anatomisches Institut, Pestalozzistrasse 20, Basel, Switzerland WITTENBERG, DR. JONATHAN B., Department of Physiology and Biochemistry, The Albert Einstein College of Medicine, New York 61, New York WRIGHT, DR. PAUL A., Department of Zoology, University of New Hampshire, Durham, New Hampshire 03824 WRINCH, DR. DOROTHY, Department of Physics, Smith College, Northampton, Massachusetts WYTTENBACH, DR. CHARLES RICHARD, Department of Anatomy, University of Chicago, Chicago 37, Illinois YXTKMA, DR. CHESTER L., Department of Anatomy, State University of New York, College of Medicine, Syracuse 10, New York YOUNG, DR. D. B., Main Street, North Hanover, Massachusetts ZIMMERMAN, DR. A. M., Department of Pharmacology, State University of New York, Downstate Medical Center, Brooklyn 3, New York ZINN, DR. DONALD J., Department of Zoology, University of Rhode Island, Kings- ton, Rhode Island ZIRKLE, DR. RAYMOND E., Department of Radiobiology, University of Chicago, Chicago 37, Illinois ZORZOLI, DR. ANITA, Department of Physiology, Vassar College, Poughkeepsie, New York ZULLO, DR. VICTOR AUGUST, Marine Biological Laboratory, Woods Hole, Massa- chusetts 02543 ZWEIFACH, DR. BENJAMIN, New York University, Bellevue Medical Center, New York, New York 10016 ZWILLING, DR. EDGAR, Department of Biology, Brandeis University, Waltham 54, Massachusetts ASSOCIATE MEMBERS ALTON, MRS. BENJAMIN ANDRES, MRS. WILLIAM ARMSTRONG, MRS. PHILIP B. AUCLAIR, DR. AND MRS. WALTER BACON, MR. AND MRS. ROBERT BAKALAR, MR. AND MRS. DAVID BALL, MRS. ERIC G. BARBOUR, MRS. Lucius 11. BARROWS, MRS. ALBERT W. BARTOW, MR. AND MRS. CLARENCE W. BARTOW, MRS. FRANCIS D. BARTOW, MRS. PHILIP BEALE, MR. AND MRS. E. E. P.i.r.L, MRS. ARTHUR W. BIGELOW, MRS. ROBERT P. BRADLEY, DR. AND MRS. CHARLKS BROWN, DR. A\D MRS. F. A., JR. BROWN, MRS. THORNTON BI-RDICK, DR. C. LALOR BUTLER, DR. AND MRS. E. G. CAHOON, MRS. SAMUEL T., SR. CALKINS, MRS. GARY N. CALKINS, MR. AND MRS. G. N., JR. CAREY, Miss CORNELIA CARLTON, MR. WINSLOW G. CLAFF, MRS. C. LLOYD CLAFF, MR. MARK CLARK, MRS. JAMES B. CLARK, MRS. LEROY CLARK, MR. AND MRS. VAN ALAN CLOWES, MR. ALLEN W, CLOWES, MRS. G. H. A. CLOWES, DR. AND MRS. GEORGE IT. A., JR. I'OI.TON, MRS. IT. SEYMOUR CON K 1.1 N. Miss ISABEL ("KAMKR, MR. AND MRS. IAN D. W. CRANE, MR. JOHN REPORT OF THE DIRECTOR 63 CRANE, MR. JOSEPH B., Foundation CRANE, Miss LOUISE CRANE, MR. STEPHEN CRANE, MRS. W. CAREY CRANE, MRS. W. MURRAY CROCKER, MR. AND MRS. PETER J. CROSSLEY, Miss DOROTHY CROSSLEY, MR. AND MRS. ARCHIBALD M. CROWELL, MR. AND MRS. PRINCE S. CURTIS, DR. AND MRS. WILLIAM D. DAIGNAULT, MR. AND MRS. A. T. DANIELS, MR. AND MRS. B. G. DANIELS, MR. AND MRS. F. H. DAY, MR. AND MRS. POMEROY DRAPER, MRS. MARY C. DREYER, MRS. F. A. DuBois, DR. AND MRS. A. B. ELSMITH, MRS. DOROTHY ENDERS, MRS. FREDERICK EVVING, MR. WILLIAM FAXON, DR. AND MRS. NATHANIEL W. FIRESTONE, MR. AND MRS. EDWIN FISHER, MRS. B. C. FORBES, DR. ALEXANDER FRANCIS, MR. LEWIS H., JR. GAISER, DR. AND MRS. DAVID W. GALTSOFF, MRS. PAUL S. GARFIELD, Miss ELEANOR GARLOCK, MR. AND MRS. ROBERT GlFFORD, MR. AND MRS. JOHN A. GlLCHRIST, MR. AND MRS. JOHN M. GILDEA, DR. MARGARET C. L. GILLETTE, MR. AND MRS. ROBERT S. GLAZEBROOK, MRS. JAMES R. GOLDMAN, DR. AND MRS. ALLEN S. GREEN, Miss GLADYS M. GREIF, DR. AND MRS. ROGER GREER, MR. AND MRS. WILLIAM H., JR. GULESIAN, MRS. PAUL J. GUREWICH, DR. AND MRS. V. HAMLEN, MR. AND MRS. J. MONROE HANNA, MR. AND MRS. THOMAS C. HARRINGTON, MR. AND MRS. R. D. HARVEY, DR. AND MRS. E. NEWTON, JR. HARVEY, DR. AND MRS. RICHARD HERVEY, MRS. JOHN P. HlRSCHFELD, MRS. NATHAN B. HOPKINS, MRS. RALPH H. 1 TOUSTON, MR. AND MRS. HOWARD E. JKWETT, MR. AND MRS. G. F., JR. JONES, MR. AND MRS. DsWiTT C., JR. KAHN, DR. AND MRS. ERNEST KEITH, MRS. HAROLD C. ROLLER, DR. AND MRS. LEWIS R. LAWRENCE, MR. AND MRS. MILFORD R. LEMANN, MRS. LUCY BENJAMIN- LOBE, MR. AND MRS. JOHN LOEB, DR. AND MRS. ROBERT F. LOVELL, MR. AND MRS. HoLLIS R. MARSLAND, DR. AND MRS. D. A. MARVIN, MRS. WALTER TAYLOR MAST, MRS. S. O. MATHER, MR. FRANK J., Ill MAVOR, MRS. JAMES W. McCuSKER, MR. AND MRS. PAUL T. MCELROY, DR. AND MRS. W. D. McGlLLICUDDY, DR. AND MRS. JOHN J. MCKELVY, MR. JOHN E. McLANE, MRS. HUNTINGTON McViTTY, MRS. A. E. MEIGS, MR. AND MRS. ARTHUR MEIGS, DR. AND MRS. J. WISTER MINIS, MR. AND MRS. ABRAM J., JR. MITCHELL, MRS. JAMES McC. MITCHELL, MRS. PHILIP MIXTER, MRS. WILLIAM JASON MOSSER, MRS. BENJAMIN D. MOTLEY, MRS. THOMAS NEWTON, Miss HELEN K. NICHOLS, MRS. GEORGE NIMS, MRS. E. D. THE AARON E. NORMAN FUND, INC. PACKARD, MRS. CHARLES PARPART, DR. AND MRS. ARTHUR K. PARK, MR. MALCOLM S. PATTEN, MRS. BRADLEY PENNINGTON, Miss ANNE H. PHILIPPE, MR. PIERRE PUTNAM, MR. AND MRS. WILLIAM A., Ill REDFIELD, DR. AND MRS. ALFRED C. REZNIKOFF, DR. AND MRS. PAUL RIGGS, MR. AND MRS. LAWRENCE, III RIVINUS, MRS. F. M. ROGERS, MRS. CHARLES E. ROOT, DR. AND MRS. WALTER S. 64 MARINE BIOLOGICAL LAI'.OKATORY RUDD, MRS. H. W. DWIGHT RUGH, DR. AND MRS. ROBERTS SANDS, Miss ADELAIDE G. SAUNDERS, MR. AND MRS. LAWRENCE SCHWARTZ, MRS. VICTOR B. SmvERicK, MRS. ARTHUR SINCLAIR, MR. AND MRS. \Y. RICHARD- SON SMITH, MRS. HOMER P. Si '!:! DEL, MRS. CARL C. STONE, MR. AND MRS. LEO STONE, DR. WILLIAM, JR. STONE, MRS. SAMUEL M. STRAUSS, MR. AXD MRS. DONALD B. STUNK ARD, MRS. HORACE SWIFT, MR. E. KENT, JR. SWOPE, MR. DAVID SWOPE, MR. AND MRS. GERARD, JR. SWOPE, Miss HENRIETTA H. SZENT-GYORGYI, DR. ALBERT TOMPKINS, MR. AND MRS. B. A. WARREN, DR. AND MRS. SHIELDS WEBSTER, MRS. EDWIN S. WHITELY, Miss MABEL W. WHITELY, MR. AND MRS. GEORGE C., JR. WHITNEY, MRS. GEORGE WlCKERSHAM, MRS. JAMES H. WILHELM, DR. HAZEL S. WILSON, MRS. EDMUND B. WILSON, DR. MAY G. WOLFE, DR. CHARLES WOLFINSOHN, MRS. W. YNTEMA, MRS. CHESTER L. V. REPORT OF THE LIBRARIAN The summer of 1964 saw many physical changes in the Library. The older section of the stacks was repainted, new tile flooring put down on all five floors, and lighting changed completely to a fluorescent system. New lights were placed on all tables in the wing and the reserve desks now contain file cabinets. A large catalog room, three new offices for the staff, and a Xerox room were added to the existing space. Also, for the first time, all of our most valuable books were brought together in a Rare Books Room, which is lined with floor-to-ceiling paneled shelv- ing and contains as of this date 517 volumes. This room is located within the offices and is available only while the staff is on duty. During the year we received and serviced 844 requests on Interlibrary Loan, and we requested 137 titles for our use here. In the Fall, 1545 volumes were sent to the bindery. A very generous gift of nearly 2000 reprints was received from Dr. William Randolph Taylor. The total number of bound volumes in the Library is now approximately 100,000. The Library holdings for this year are : Total Number of Serial Titles in Library 3567 Number Received Currently 1917 ' )n Subscription 788 ( )n Exchange (with Biol. Bull., Coll. Reprints) 874 < n Gift Basis 255 Total Number of Hooks in I .ibrary 15,384 Number Added in I'M ' -!(>_' Received I'Yom Book Exhibit 101 Total Number of Reprints 231,351 Xnml.er Added in I'M 3351 I AXE FESSENDEN, Librarian REPORT OF THK TREASl'RKR 65 VI. REPORT OF THE TREASURER The market value of the General Endowment Fund and the Library Fund at December 31. 1964, amounted to2.370.890 as against book value of $1,235,860. This compares with values of$2.155.4X9 and $1,242,89(>. respectively, at the end of the preceding year. The average yield on the Securities was 3.51% of tin market value and 6.74% of the book value. The total uninvested principal cash in the above accounts as of December 31, 1964. was$5,595. Classification of the
securities held in the Endowment Funds appears in the Auditor's report.
The market value of the pooled securities as of December 31. 1964 was $5X0,077 with uninvested principal cash of$2,210, the market value at December 31, 1963,
being $390.026. The book value of the securities in this account was$562,547 on
December 31, 1964, compared with $315,196 a year earlier. The average yield on market value was 3.6% and 4.6% of book value. The proportionate interest in the Pool Fund Account of the various Funds as of December 31, 1964. is as follows : Pension Funds 23.098% General Laboratory Investment 32.2<>4' , Other : Bio Club Scholarship Fund 923' , Rev. Arsenius Boyer Scholarship Fund 1.130' < Gary N. Calkins Fund 1.059% Allen R. Memharcl Fund 206% F. R. Lillie Memorial Fund 3.566% Lucretia Crocker Fund 3.860' . E. G. Conklin Fund 652% Jevvett Memorial Fund 343' '/ M. If. Jacobs Scholarship Fund 4(>5' - Anonymous Gift 1 .221 % Herbert W. Rand Fellowship 23.326' \ Mellon Foundation 7.8X7' , Donations from the MBL Associates for 1964 were$4,830.00 as compared \vith
$4,295.00 for 1963. Unrestricted gifts from foundations, societies and companies amounted to$14,575.
During the year, we administered the following grants:
Investigators Training .I//. 1 /, Institutional
13 NIH 3 NIT I 4 Nil I
3 NSF 2 NSF 3 NSF
1 Ford 3 ONR
1 ONR 1 A EC
1 Commonwealth 1 Ford
19 M
66 MARINE BIOLOGK ^LABORATORY
The rate of overhead on grants to investigators is 20%, based on the amount
expended. The overhead on these Brunts for this year amounted to $81,239 as com- pared with$5(>.4 ( >4 for the preceding year.
The Lillie Fellowship Fund, with a market value of $114,293 and a hook value of$92,893. as well as the investment in General Biological Supply House with
book value of SI 2.70(\ is carried in the Balance Sheet item "Other Investments."
The General biological Supply House fiscal year ended June 30. 1964, and had
a profit after taxes >f S30 l| .<>51 as compared to $241,616 in 1963 and$302,657 in
1 ( '<>2 and $302.S51 in WM and$314,034 in 1960.
In the fiscal year 1 ( ><>4 the Marine Biological Laboratory received dividends
from the General Biological Supply House of $63,500 as against$42,164 in 1963,
$38.100 in 1962.$33.020 in 1%1. and $30,480 in I960. Following is a statement of the auditors: I'd ///< 'J'nistccs oj Marine Hioloc/ical Laboratory, U'oods Hole, Massachusetts: \Ye have examined the balance sheet of Marine Biological Laboratory as at December 31. 1904, the related statement of operating expenditures, income and current fund and statement of funds for the year then ended. Our examination was made in accordance with generally accepted auditing standards, and accord- ingly included such tests of the accounting records and such other auditing proce- dures as we considered necessary in the circumstances. We examined and have reported on financial statements of the Laboratory for the year ended December 31. 19(,4. In our opinion, the accompanying financial statements present fairly the assets, liabilities and funds of Marine Biological Laboratory at December 31, 1964 and 1963 and the results of its operation for the years then ended on a consistent basis. The supplementary schedules included in this report were obtained from the Laboratory's records in the course of our examination and in our opinion, are fairly stated in all material respects in relation to the financial statements, taken as a whole. I 'oston, Massachusetts March 26, 1W>5 LYBRANI>, Ross BROS. & MONTC.OMKRY JAMKS If. WICKHRSHAM, Treasurer REPORT OF THE TREASURER 67 MAR I XI-: BIOLOGICAL LABORATORY BALANCE SHEETS December 31, 1964 and 1963 Investments !<Jf>4 10f>3 Investments held by Trustee: Securities, at cost (approximate market quotation 1964$2,370,890) ................................ . $1,235,860$1,242,896
Cash. 5,595 431
1,241,455 1,243,327
Investments of other endowment and unrestricted funds:
Pooled investments, at cost (approximate market quotation 1964
$579,161) less$5,728 temporary Investment of current fund
cash 479,344 309,468
Other investments 118,888 120,424
Cash 39,522 14,083
Accounts receivable 10,664 21,131
$1,889,873$1,708,433
Plant Assets
Land, buildings, Library and equipment (note) 5,136,289 4,931,472
Less allowance for depreciation (note) 1,378,887 1,313,162
3,757,402 3,618,310
Construction in progress 109,215
Short-term investments, at cost 192,360
$4,058,977$3,618,310
Current Assets
Cash 79,637 100,991
Temporary investment in pooled securities 5,728 5,728
U. S. Treasury bills, at cost 96,045 74,324
Accounts receivable (U. S. Government, 1964 $84,793 ; 1963$95,142) 138,489 140,825
Inventories of specimens and Bulletins 33,401 45,288
Prepaid insurance and other 6,844 7,062
$360,144$ 374,218
68 MAUIXK 1:101. ()<;K \i. I.AHOK
MARINE BIOLOGICAL LAB( )RAT( )RY
BAI.AM i-. SIIKI-:TS
December 31, 1964 and 1963
l\ndir:i'inent Funds l<><->4 I'HtJ
I ndowmenl funds gixen in trust for beneht ot the Marine Biological
Laboratorv. 81,241,455 si, 243, 327
Endowment funds for awards and scholarships:
Principal.. 295,710 12(>,980
Unexpended income. 14,289 12.077
309,999 139,057
rnre-trii ted funds functioning as ciulowment . . . . 206,378 206,378
Retirement fund. 123,298 108,481
I'ook-d in\ c-i mrnt> accumulated gain 8,743 11,190
81,889,873 $1,708,433 Plant Funds Funds expended for plant, less retirements 5,245,504 4,931,472 I .e-^ allowance for depreciation charged thereto 1,378,887 1,313,162 3,866,617 3,618.310 1 nexprnded plant funds. 192,360$4,058,977 $3,618,310 Cm-rent Liabilities and Funds Accounts payable and accrued expeu-.es. 33,315 62,763 Advance Mibscriptiou, 10,926 10,362 I'nexpended grants research.. 99,000 110,433 I Hexpended balances of gifts for designated purposes 17,995 13,531 Current fund 1'>S,908 177,129 360,144$ 374,218
\ ole. The Laboratory lias since Janu.u v 1 , 1916, provided for reduction ol book amounts ol
])laut assets and funds in\-ested in plant at annual rates ranging from 1 % to 5% of the original cost
ol the assets.
RKl'ORT Ol-' THK TRKASURER 6<)
MAR I NIC BIOI.OC.ICAI. LABORATORY
STATEMENTS OF ( )IM-:K ATFNC; KXPHXIHTIRKS, INOIMK AND (YKKKNT I-VND
Years Funded December 31, 1964 and 1963
Operating Expenditures
Research and accessory services - 5
1964
5 293,396
1963
$? 73 3^3 Instruction 160,820 147,163 Library and publications (including book purchases 1964,$24,304;
1963, $25,628) 80,416 77,922 1 'irect costs on research grants . 493,890 484 640 I )irert costs on institution support grants . . 150,450 129.64 7 Administration and general 1,178,972 IP, 453 1,112,700 97,339 Plant operation and maintenance 139,684 11 1,441 Dormitories and dining 1 75,696 174,030 Additions to plant from current income 5 045 7 793 Less depreciation included in plant operation and dormitories and dining above but charged to plant funds ... 1.611,850 67,437 1 ,503,303 67,47? 1,544,413 1,435,831 Income Research fees 88,240 113,024 Accessory services (including sales ot biological specimens 1964,$42,051 1963, $38,019) 114,181 103,398 I nstruction fees .... 28,470 28,461 Library fees, Bulletins, subscriptions and other 49,393 43,952 Dormitories and dining income 133 759 129486 Grants for support of institutional activities: Instruction and training 138,540 131,564 Support services . 150,450 129,642 General 109,219 113,853 Reimbursements and allowances for direct and indirect costs on specific research grants 575,129 541,134 Gifts used for current expenses 22,135 29,285 Investment income used for current expenses 156,676 134,591 1,566,192 1 .498,390 Kxcess current income 21,779 62,559 Current fund balance January 1 177.129 114,570 Current fund balance December 31 . .$ 198,908 $177,129 70 MARIXK HIOI.fH.H \l. I. . \MORATOK V M. \RI\T. BIOLOGICAL L.\B( )RATORY Si \TKMKNT OF Fl'NDS Year Kndod December 31, 1%4 (Hits and Invest- I 'ted for Other .fun may Oilier men! Current Expendi- 1, l"t>4 Receipts Income Expenses hires Invested funds. .$1,708,433 $187,132$164,448 $153,890$16,250
Unexpended plant
funds.. 452,800 1,575 262,015
Unexpended research
jrrants.. . $_110.4.U 1,110,905 1,122,338 Unexpended gilts tor designated purposes. 8 13,531 29,687 22,135 3,088 Current fund . .$ 177,129 21,779(1)
$1,802,303$166,023 $1,298,363$281,353
Grant fur facilities. . . . 452,800
Grants for rex-arch,
training and
support.. 1,110,905
Appropriated from cur-
rent income and
other 22,722
Net loss on sale ol
securities (4,350)
Excess of current in-
come over expendi-
tures.. 21,779(1)
$1,802.303 Expended for con- struction and renovation of facilities 262,015 Scholarship awards 4,124 Payments to pensioners. . . 1 2,126 Other. 3,088 Balance December 31, 1964$1,889,873
$192,360$ 99,000
$17,995$ 198,908
S281.353
REPORT OF THE TREASURER
71
MA RIM: BIOLOGICAL LABORATORY
SlMMAKY OF IXVF.STMIXTS
I )r(Vllll)lT .11,
Securities held by Trustee:
General endowment fund:
U. S. Government securities
Corporate bonds
Preferred stocks
Common stocks
General Educational Board
endowment fund:
U. S. Government securities
Other bonds
Preferred stocks
Common stocks
Total securities held by
Trustee
Investments of other endowment
and unrestricted funds:
Pooled investments:
U. S. Government securities
Corporate bonds
Common stocks
Less temporary investment
of current fund cash. .
Cost
; 92,310
528,638
54,422
358,452
1,033,822
1,235,860
61,005
125,736
298,331
485,072
(5,728)
170.344
Other investments:
U. S. Government securities 27,947
Other bonds 15,031
Preferred stocks 3,728
Common stocks 58,887
Real estate 13,295
11 8, "888
Total investments of
other endowment and
unrestricted funds. . . $598,232 Total investment income Custodian's fees charged thereto. . . . Investment income distributed to funds Plant investments: U. S. Treasury bills, due 3/4/65 . 80,085 Bank of New York acceptances, due January, 1965 112,275$ 192,360
Current investments:
U. S. Treasury bills, due March 4
and October 31, 1965 $96,045 Temporary investment in pooled securities. . .$ 5,728
% of
Total
8.9
51.1
5.3
34.7
100.0
18,086 8.9
107,310 53.2
15,641 7.7
61,001 30.2
202,038 100.0
12.6
25.9
61.5
100.0
Market
Quotations
$91,086 522,095 53,200 1,306,140 1,972,521 17,836 109,091 15,100 256,342$2,370,890
59,730
125,370
394,061
%of
Total
4.6
26.5
2.7
66.2
100.0
4.5
27.4
3.8
64.3
398,369 100.0
10.3
21.7
68.0
579,161 100.0
Investment
Income
1964
$4,449 21,177 2,186 42,950 70,762 1,221 4,106 700 6,508 83,297 2,308 4,782 7,489 74^79 (251) 14.328 1,312 749 130 65,576 67.767 82,095 165,392 (944) 164,448 684 891 1,575 2,686 251 2,937$168,960
THE [NDUCTIVE ROLE OF THE YOLK EPITHELIUM IX THE
DEVELOPMENT OF THE SQUID, LOI.Kio
PEALI] (LESUEUR) 1 - ;
'i IHN M. ARXOLD
ii' l-iio!i>iiiciil Laboratory, H'onds Hole. Massachusetts 02^-13, and the I)cf>arlincnl of
/.oolou\, I'lih't'rsifv of Minnesota, Minneapolis, Minnesota 55/.v ::
While a fairlv large body of information exists on the descriptive aspects of
the embrvologx of the cephalopods, relatively little experimental work has been
done on these animals. These embryos seem superficially to be ideally suited to
embryological analysis since they are large, abundant, and are relatively easy to
obtain (Arnold, 1 () (>2>. ( >ne of the major difficulties has been the inability to
work with embryos outside of the chorion. Ranzi (1931) tried to raise Sepia
officinalis in sea water but had little success. He was able to isolate various organs
and parts of the embryos of Sepia by operating through the chorion. and concluded
that isolated organs and tissues were capable of self-differentiation. This technique
severely limited operative procedures, and he was forced to use rather late stages,
( Xaef stage XII : - Arnold stage 2(> ) in which most of the organ primordia were
rather well formed.
In the summer of 1 ( ">1 it was possible to devise culture techniques by which
the dechorionated embryos would survive and develop normally. This has allowed
some experimental analysis of young embryos of the common Atlantic coast squid,
l.i >l it/i i pealii.
MATERIALS AND METHODS
Since the techniques used in this study have not been fully described, it is
necessary to give a detailed account of the procedures used. Most of the experi-
ments were performed in ritro in a culture medium made of three basic components:
whole adult squid blood, sterile sea water, and an antibiotic stock solution. The
blood was drawn under sterile conditions from the vena cava of the adults and
stored frozen in 3-ml. glass lubes. Before use it was thawed and diluted with an
equal volume of sterile sea water, To this was added about ]' ', of an antibiotic
Mock solution composed of 0.5'r streptomycin, 0.05 r / phenol red, and 50,000 units
of potassium penicillin <i in double-distilled water which had been saturated with
sulfadia/ine. The embryos were cultured in glass vessels made expressly for this
depressions in the bottom lor holding tin- embryos. This culture vessel was placed
' This work is a portion of a tin-sis submitted in partial fulfillment of the Ph.D. require-
ments of the Department ot /oology, I niversity of Minnesota.
- 1'art of this \\ork was done while the author was the recipient of an X.S.I'". 1 'redortoral
hellow ship.
( in-rent addles : Department ot Zoology and Kntomolo<>y, Iowa State I'liiversity, \rnes,
[owa, ?onln.
72
INDUCTION IX LOLIGO
in a covered preparation dish to which a few drops of sterile sea water had been
added to saturate the atmosphere and maintain osmotic equilibrium with the medium
in the vessel.
The embryos were prepared for culture by stripping off the outer tunics of the
egg string with the fingers, cutting up the denuded string and transferring indi-
vidual embryos in their chorions through two changes of sterile sea water. The
chorion was then torn open and the embryo washed twice in sterile sea water. The
operative procedures described below were performed and the embryo was then
transferred to the freshly prepared medium. The embryos were incubated at 18 C".
(0.5 C.) and examined twice daily. The medium was changed every second
day when the experiments exceeded this length of time.
Under these conditions the embryos appeared to develop completely normally
when compared with control embryos still in their chorions and in normal sea
water. The cultured embryos seemed to develop slightly faster than the controls,
possibly because of greater availability of oxygen due to the lack of the chorion.
Some embryos were maintained for 178 hours in culture with no apparent adverse
effects. If the medium was not changed at least every three days, development
would slow down. This effect was reversed by the addition of fresh medium.
Parts of the stage H> and 17 embryos (Arnold, 1965) were removed with stain-
less steel needles before culturing. At these stages, the cephalopod embryo con-
sists essentially of an outer layer of cells (future body of the embryo), a layer of
greatly flattened cells (yolk epithelium), and a central mass of yolk. The various
organ primordia could be identified by the thickened nature of the outer layer of
cells (columnar z<s. cuboidal cells) and the asymmetrical nature of the egg. Most
of the operations involved removal of the parts of the eye, but the same confirming
experiments were also done on the otocyst, arms and funnel folds. Three different
types of operations were performed. The first involved the removal of the whole
eye primordium, including some of the underlying yolk. This isolate would round
up and the yolk would become incorporated within the center. These isolates sur-
vived quite well in the culture medium and underwent considerable differentiation.
The second operation separated the outer layer of cells from the yolk epithelium.
This was accomplished by gently rubbing the cells with the blunt edge of a needle
until the cells became loosened and somewhat sticky. The outer layer of cells could
then be caught on the point of a needle and pulled off in a sheet. A second needle
was used to cut the sheet of cells well beyond the organ primordium. \Yith practice,
about one-fourth to one-third of the total surface of the outer cells could be removed
and the embryo transferred to culture medium with only a few minutes exposure
to sterile sea water. Sections of unstripped and stripped embryos are shown in
Figures 1 and 4. In a few cases the eye anlage was removed by the technique
described below for dissociating cells. A large number of embryos was examined
and appropriate ones were selected. In the third operation the outer layer of cells
was stripped and a small portion of the yolk epithelium removed. This was rather
hard to accomplish since the embryos tended to lose volk from the wound, which
mechanically inhibited wound healing. However, enough cases were successful so
interpretable results were obtained. In a few cases masses of cells were grafted
onto the freshly stripped yolk epithelium. 'I hese cells were obtained bv cutting
up an egg string and shaking it in sea water adjusted to pH 5 with 1 \ T HC1
74
1
10
|''K;CRKS 1-10.
[NDUCTION IX l.ni.K.n 75
until the egg-jelly dissolved. ( )nce the egg-jelly was completely dissolved and
the embryos inside their chorion were completely free, the embryos were shaken
violently for about seven to ten minutes. The outer layer of cells was dissociated
from the embryos, and usually single cells or small groups of cells resulted. The
embryos were immediately examined, and those which appeared to be well disso-
ciated were selected. At stage 17 the dissociated cells would reaggregate and form
small solid clumps in about 15 minutes. These small clumps would fuse until
about seven to fifteen aggregates remained in each chorion. Although these clumps
would remain alive for extended periods, no organ or tissue differentiation was
ever observed. Newly formed aggregates (one to two hours after dissociation )
were stained in a solution of neutral red (0.01^) and grafted onto the freshly
stripped yolk epithelium. The aggregates stuck quite readily and tended to flatten
out on the surface of the embryo. The aggregates remained visible and were
easily distinguished from the cells of the host embryo by their dye content.
RESULTS
\\hen the whole eye primordium was removed, together with some of the sur-
rounding tissue and underlying yolk, the resultant isolate rounded up with the yolk
on the inside. These isolates differentiated quite normally and complete organs
were formed (Figs. 2 and 3). The wound on the donor embryo lost a portion of
yolk, but eventually the edges of the wound closed, development continued, and the
unoperated organs differentiated normally. There was no evidence of any regen-
eration or replacement of the organs removed (Fig. 5). A total of 25 operations
was performed on stage 17, and 13 operations on stage 16 embryos. In all cases
the results of these operations were the same. The possibility of inhibition of
development due to operative trauma was checked by a series of sham operations
in which either less than the whole eye primordium was removed or a few cuts
were made in the surface of the embryo. In these cases there was loss of yolk at
the site of the wound but after healing normal development ensued.
Removal of the outer layer of cells resulted in a different pattern of develop-
ment. The isolated cells usually formed a small clump that showed no further
differentiation and lost the characteristics formerly possessed. These small clumps
of cells did not survive well, possibly due to the trauma of surgery. Of those that
FIGURE 1. Section of the eye region of a stage 17 embryo. Note the yolk epithelium and
the columnar nature of the outer layer of cells. Epon 812, Azure II-methylene blue; 660 X.
FIGURE 2. Isolated organs of the embryo shown in Figure 5. Both the outer layer <>t cells
and the yolk epithelium were isolated; ca. 190 X.
FIGURE 3. Lower section of the same isolate as in Figure 2. In culture 45 hours.
FIGURE 4. Section of the yolk epithelium after removal of the outer layer of cells. One
yolk epithelium cell has rounded up abnormally above the rest of the yolk epithelium; 660 X.
FIGURE 5. Donor embryo for Figures 2 and 3. Note lack of organs on one side.
FIGURE 6. Regenerated otocyst after removal of the outer layer of cells; 900 X.
FIGURE 7. Control eye for Figure 10; 725 X.
FIGURE 8. Section through the retina of a stripped embryo onto which dissociated-reaggre-
gated cells were grafted. In culture 40 hours; 1000 X.
FIGURE 9. Dissociated-reaggregated cells after 55 hours. Note the lack of any tissue
differentiation; 1000 X.
FIGURE 10. Regenerated eye after removal of only the outer layer of cells. Compare with
Figure 7.
76
did survive, no evidence of differentiation could he detected. Tin- wound produced
In this operation was closed In migration ol the surrounding outer layer of cells
Over the denuded yolk epithelium. In coxering the yolk epithelium the cells would
cut off any small hlehs of yolk that occasionally resulted from small punctures
accidentally produced in the \olk epithelium during the operation. That these cells
of the outer layer actually migrated over the wound rather than grew there was
demonstrated In the speed at which the covering took place (one to two hours)
as well as In a series of careful ohservations during wound closure. A total of
2\ stage 17 and If) stage 1<> emhryos was operated on in this fashion and all were
cultured for at least 45 hours. In all of these cases the cells which migrated over
the stripped yolk epithelium differentiated with the structures that would have
normally differentiated in that site. In some cases (8) one-third of the total outer
layer of cells was removed, vet the resultant emhryos had all of their organs when
examined and sectioned after approximately 48 hours in culture (Figs. 7 and 10).
There seemed to he a slight retardation of development of the replaced organs hut
otherwise the cour.se of development corresponded exactly to that of the unoperated
side of the embryo. The eve. otocyst, arms and funnel folds could he thus stripped
off and replaced In the cells normally destined to form other organs (c.c/.. Fig. 6).
Since the ahove results would implicate the yolk epithelium as possibly haying
a causal role in the differentiation of the oyerlying cells, two other experiments
were attempted to test this hypothesis. The first of these involved stripping off
the outer layer of cells of stage 17 emhryos and removing a small portion of the
yolk epithelium. This was not easily accomplished because the yolk epithelium
was easily torn. I lowever, in two cases the yolk epithelium in the future region of
the otocyst was successfully removed and development was carefully followed. In
this case closure of the wound proceeded as before and differentiation of the organs
followed but the embryo lacked the otocyst on the operated side. The second
test involved grafting dissociated-reaggregated cells onto the freshly denuded yolk
epithelium. Normally these aggregated cells survived in the culture medium for
extended periods and gradually died and disintegrated. In no case did any of the
aggregates resulting from well dissociated embryos ever show any interpretable
differentiation (Fig. 9). When these cells were grafted onto the denuded yolk
epithelium, they stuck unite readily and spread out slightly. The position and ex-
tent of the grafted cells could be easily ascertained by the dye they contained.
When sectioned it appeared that those cells in contact with the yolk epithelium
differentiated into rather normal-looking tissue which corresponded to the location
on the embryo (Fig. 8). In the case' of the primordial retina, the cells became
columnar in appearance, underwent mitosis in the characteristic position, and ap-
peared to be well incorporated in the host organ. In eight successful cases, parts
of four gratis unquestionably became incorporated into the developing retina. In
the remaining case the results were not as clearcut because of yolk leakage at the
site of the graft.
The possibility of the yolk playing a significant specific causal role in the dif-
ferentiation was eliminated by experimentally removing up to one-half of the yolk
of the embryo. Despite this rather large loss in volume the embryos differentiated
normally but were reduced in size, particularly in the yolk sac region. These
results agree with those obtained by ( >kada ( 1"J7) on l.o/ii/n hlcckcri.
ixnrcTiox ix LOLK.O 77
DISCUSSION
The results reported have led the author to the conclusion that the cells of tin-
outer layer are indeterminate in their fate unless influenced In the underlying yolk
epithelium. This appears to tit the classic ideas of embryonic induction, with the
yolk epithelium being the inductor and the outer layer of cells responding to its
inductive influence. This can he stated with certainty for the eye and otoc\>t and
as probable for some of the other organs (funnel folds, arms and gills). Organs
other than these remain to be tested, but preliminary experiments indicate that tlicii
development is of the same general nature. It appears, therefore, that all of the
organs of the embryonic body are laid out in inductive areas of the yolk epithelium
and are fairly localized. Tbis can be visualized as a "morphogenetic inductive
map" in which developmental information is transferred to the highly labile or in-
different cells that overlie it. One of the rather unique features of this inductive
map is its two-dimensional nature. Unlike many other systems in which induction
occurs within a mass of heterogeneous tissue, the inductor in this case is present as
a sheet. This system, therefore, should be more amenable to experimental analyst
because the presumptive areas of the embryo can be rather easily localized and
subjected to direct experimental analysis. Preliminary experiments with chemical
treatment of the denuded yolk epithelium offer encouragement along these lines.
The problem of how to fit these results with the classical ideas of mosaic de-
velopment of the molluscs is an open question. It is obvious that part of the
embryo (the yolk epithelium ) is rather rigidly fixed in its fate while the outer layer
of cells is quite labile and subject to the inductive influences of the yolk epithelium.
Just when and how this developmental information arises is still unknown but
preliminary experiments indicate that the egg cortex of this embryo is also rather
rigidly patterned and the morphogenetic patterns would then be referred ultimately
to the ovary. Obviously, further work along these lines is indicated.
I would like to thank Drs. K. C. Shaw and A. L. Allenspach for reading this
manuscript. Special thanks are due to Dr. Nelson T. Spratt. Jr. for his help and
guidance with this work.
SUMMARY
1. Techniques for the in i'itro culture of dechorionated Loligo pcalii embryos,
involving the use of whole adult squid blood, sterile sea water, and antibiotics,
have been devised. Essentially normal development will take place in this culture
medium.
2. The embryos in stages 10 and 17 are composed essentially of three com-
ponents: an outer layer of cells, an inner cellular yolk epithelium, and the central
mass of yolk. \Yhen the outer layer of cells and the yolk epithelium are isolated
together, normal histogenesis and development will occur. \\ hen the outer layer
of cells is isolated by itself, no differentiation occurs. This leads to the conclusion
that the yolk epithelium induces the outer layer of cells to differentiate. This con-
clusion was upheld by grafting and deletion experiments.
3. The role of the yolk epithelium, therefore, may be in acting as a "morpho-
genetic inductive map."
JOHN M. \K\OI.D
I I II R \ i QRE CITED
ARNOLD, I. M.. I'>n2. Mating behavior and social structure in Lulii/o pculii. Hint. Hull.. 123:
53-57.
AKXOLD, I. M., 1%5. Xonnal cmhryunir stages of the squid, Lolif/o pcalii (Lesueur). Jiinl.
Bull., 128: 24-32.
\ \i r. A., 1 ( '2>\ Die C'e]ilialnp ( uli-i:. Monographie 35. Fauna e Flora del (iolfo di Xapoli,
Vol. 1.
OKADA, ^"., 1^27. \"ersui-lic iilier die \\irkung der Dotterwegnahme am meroblastischcn FA.
Zool. Ans., 73: 2SO- 2S4.
I\\\/i, S., l')31. Sviluppo di parti isolate di enihrioni di Cefalopcxli. 1'nhh. Stu::. Znol.
\tipoli. 11: 104-146.
PHASE-SHIFTING A LUNAR RHYTHM IX PLAXARIAXS B
ALTERING THE HORIZOXTAL MAGNETIC VECTOR 1
FRANK A. BROWN, JR. AND YOUNG H. PARK
Department of Biological Sciences, Northwestern University, r.i'anxton, Illinois
It has been demonstrated that planarian worms directed initially northward
in the late morning hours in an unvarying field-pattern of illumination will displav
a synodic monthly variation in their tendency to alter their course (Brown, 1962,
1963). From about September to March, the worms veer maximally to the left
at new moon and to the right at full moon. During March and April the monthly
rhythm typically becomes gradually transformed into a semi-monthly one with
maxima in right-veering at both new and full moon, and left- veering at the moon's
quarters.
The natural synodic month owes its existence, of course, to the periodic inter-
ference between the solar-daily and lunar-daily cycles, and hence it is reasonable
to presume that the worms in the generation of their synodic monthly periodism,
which remains phase-synchronized in a characteristic temporal relationship to the
geophysical cycles, are depending upon responses to pervasive geophysical varia-
tions possessing both of these two important natural physical frequencies.
This monthly phenomenon was investigated under each of three experimental
conditions on mornings during November through January, 1960-61. The con-
ditions were: (1) controls in the unmodified ambient field, (2) augmenting tin-
natural horizontal magnetic vector to 4.0 gauss, and (3) imposing a 4.0-gauss
horizontal field in an east-west orientation. The monthly rhythm was conspicu-
ously present in the natural field, absent in the augmented north-oriented magnetic
field, and present but reduced in amplitude in the east-directed field. During these
studies the observations of path direction on any given morning for each of the
above conditions required an average of about 20 minutes to permit about 50
worm-paths to be recorded as an assay of the influence on that particular morning
of each individual experimental condition.
The more recent demonstrations of after-effects of exposures of planarians in
experimentally altered horizontal magnetic vectors with descriptions of their prop-
erties, together with suggestive variations in response dependent upon time of ex-
posure to the experimental fields (Brown, 1 ( ><>5; Brown and Park, 1965), raised
questions concerning what might be relationships of these effects and after-effects
to influences of experimentally altered weak magnetic fields on the monthly rhythm
of the worms.
The following report describes the results of an attempt to learn more concern-
ing influences of experimental changes in strength and direction of the horizontal
1 This study was aided by grants from the National Science Foundation ((J-15008) and
the National Institutes of Health ( CIM-07405), and by a contract with the Office of Naval
Research (1228-30).
79
> s <> I-'K AXK A. I!K()\\ X, JR. \XD YOUNG II. I'AKK
magnetic vector upon the monthlv variations in orientational tendencies and upon
their generating mechanism.
M. \TKKI.\I.S AND MKTHODS
The data which were used in this investigation were the same as those employed
for determining the duration of the after-effects of reversed horizontal magnetic
vectors ( lirown and Park. 1 ( ">5 I. The data were obtained over the seventh-month
period from ( )ctober S. l'X>3. through April 30, 1964. The detailed methods by
which these data were derived and the primary reductions to which they were
subjected have been described in the earlier report.
In essence, uniformly distributed over the 206-day period of the study, 3(>0
series of observations were made, in each of which series an observer determined
the average rate- of turning of north-oriented worms for each of the ten 5-minute
intervals of a continuous 50-minute period. For the first 10 minutes the worms
were in the natural ambient geophysical field. Then daring the next three con-
secutive 5-minute intervals, the worms remained continuously exposed to an ex-
perimentally reversed horizontal magnetic vector of 0.05 gauss. The final five
5-minute intervals followed return of the worms to the natural ambient field.
Similar! v, uniformly distributed over the same 206-dav period, 357 50-minute series
ot observations were being made, just like the preceding series except that the
reversed horizontal magnetic vector-strength was 4.0 gauss. Since an average
of about 14 worm-paths could be recorded during a 5-minute period, about 50,000
individual worm-paths were recorded during the study. The mean path for each
5-minute interval while in the reversed magnetic field and following its removal
was expressed as difference from the mean path for the initial 10-minute "controls."
to obtain a measure of the response to the reversed fields. The response data were
then reduced to mean responses to each field strength for each 5-minute interval
for each of 41 consecutive 5-dav periods of the study. Five-day means were used
in order to reduce the size' of the influence of day-to-dav variations in uncontrolled
^eophvsical factors.
For purposes ot the present analysis, these data permitted one to determine the
torm ot the mean monthlv variation in the path of the initial "controls," and the
form ot am mean monthly variations which might be present in the turning re-
sponses ot the worms to each of the- two reversed field strengths. It was, linallv.
possible to follow and characterize any after-effects on such rhvthmic responses
which might tend to persist following the removal of the experimental fields.
Farlier studies had indicated that monthlv variations occur in response to vcrv
weak magnetic fields. To disclose any monthly variation in response to the ex-
perimental fields ot this studv and in the 1 after-effects, the data were used in the
following manner. The mean response for each 5-dav interval was treated as if it
were a value obtained on that particular dav over which the interval was centered.
Mnis. each 5-day group could be ascribed a specific dav relative to new moon in
the natural lunar monthlv cycles The mean response was then calculated for X,
approximately equally spaced 3- or 4-dav intervals over the lunar cvcle. The in-
tervals were centered on ihe times in the monthlv cvcles which are illustrated
in ! igure 1 .
PHASE-SHIFTING A RHYTHM BY MAGNETISM
81
H
or
UJ
O
cr
LU
L_
L_
A
B
c
J L
FM
N M
FM
FIGURE 1. A. The variation in the difference between responses to the 4.0-gauss and the
0.05-gauss reversed horizontal vectors, as related to the phase of moon. B. The same difference,
but for the first IS minutes after removal of the magnets. C. The same difference, from 15 to
25 minutes after removal of the magnets.
82
FRANK A. I'.K'MU \", JR. AND YOUNG H. PARK
RESULTS
In Figure 1A is plotted the mean response of the 4.0-gauss worms relative
to that of the 0.05-gauss ones during the 15 minutes of exposure to the experi-
mental fields, as a function of phase of moon. A monthly variation is clearly sug-
gested, with a maximum difference occurring over full moon and minimum, even
possibly a reversal of the difference, over new moon. The comparable variations
of relative paths in the two field-strengths with phase of moon during the first 15
minutes following removal of the experimental field, and during the last 10 minutes
after removal, are shown in Figures IB and 1C, respectively. A monthly variation
appears to persist for a time hut to have disappeared nearly completely by 20 to
NM
FM NM
PHASE OF
FM
NM
MOON
FIGURE 2. Variation in mean path of the worms (controls) with phase of moon during
their initial 10-minute period while in the natural ambient geophysical field. The mean monthly
cycle is repeated.
25 minutes after the field removal. The rate of the disappearance of the monthly
variation in this difference strikingly coincides with the rate of loss of the general
after-effect reported earlier (Brown and Park, 1965).
The results pertaining to general after-effects which have been described pre-
viously had suggested that during this 7-month study a mean, overall response to
the two experimental field strengths occurred chiefly for the reversed 4.0-gauss
one. However, evidence was advanced to indicate that the worms also displayed
a very definite response to the 0.05-gauss reversed field but that the character of
the response varied with time more strikingly than did response to the 4.0-gauss
field, even changing in sign. The results suggested an annual variation. From
the present study it became evident upon examining separately the responses to
the two strengths of the magnetic fields, together with their subsequent after-effects,
that response to the 0.05-gauss field varies as a function of elongation of the moon.
PHASE-SHIFTING A RHYTHM BY MAGNETISM
83
To learn exactly what effect the magnet might have, it was necessary first to learn
the nature of the monthly variation of the initial controls. The presence and
characteristics of such a rhythm in worms had previously been shown and char-
acterized for morning hours. For the present study about 40% of the results
were obtained, instead, in the afternoon. Determination of the relationship be-
FM
NM
FM FM
NM
FM FM
NM
FM
FIGURE 3. A and A'. The variation in response to the 0.05- and 4.0-gauss reversed
horizontal vectors, respectively, in relation to moon phase during the first five minutes of field
application (solid line), the second five minutes (dotted line) and the third five minutes (dashed
line). B and B'. The corresponding relationships for the first three S-minute intervals follow-
ing removal of the magnets. C and C'. The corresponding relationships for the fourth 5-
minute interval (solid line) and the fifth one (dashed line) following experimental-field
removal.
tween phase of moon and means of the paths of the initial control-worms (Fig. 2)
disclosed a mean monthly pattern of variation with a maximum right-turning near
first quarter of the moon and maximum left-turning just prior to new moon.
The mean response to the reversed 0.05-gauss field (Fig. 3 A) was an immedi-
ate gross reversal of phase of this normal monthly variation. Now, maximal
right-turning occurred just prior to new moon. During the 15 minutes immedi-
ately subsequent to the removal of the experimental field (Fig. 3B) the amplitude
of this 180 phase-shifted monthly variation slightly increased and its form be-
came somewhat altered. Only relatively minor changes in the mean monthly
pattern then seem to have ensued through the 20- and 25-minute observation
84 FRANK A. BROWN, JR. AND YOUNG H. PARK
times (Fig. 3C). The new cycle. 180-shifted relative to the initial one, had
persisted in an extraordinary manner.
The mean response to the reversed 4.0-gauss field was a definite and immediate
displacement of the mean worm paths to the right of the controls and a slight
change in the monthly pattern ( Fig. 3A' I. Although there was a beginning of an
inversion of the monthly cycle, in that maximum right-turning occurred near third
quarter of the moon, there was lacking the striking immediate, essentially complete,
inversion that was observed for the response to the 0.05-gauss field. Despite,
also, quite a different transient pattern from that observed for the weaker, 0.05-
gauss, field during the 15 minutes immediately subsequent to magnet removal
(Fig. 3B') the increased general right-turning behavior gradually subsided and a
persistently altered monthly pattern of response became evident (Fig. 3C). The
patterns of monthly variation in response witnessed during the 20- and 25-minute
periods were quite similar to those observed for the corresponding periods following
the removal of the 0.05-gauss reversed field, and again were essentially 180-
shifted relative to the phase of the initial control pattern.
A disappearance of all differences between the patterns of the monthly variation
following the magnetic response and the pattern of the initial controls would
have been expected if the shifted rhythm had gradually been lost over the 25-
minute post-magnet period. And yet, the worms from both magnetic series (Fig. 3C
and 3C') now displayed, in common, a monthly pattern of difference from the
initial controls which resembled astonishingly a cycle 180 "-phase-shifted from that
one which was present before the submission to the 15 minutes of the geographically
reversed experimental magnetic field. The relationship, relative to nciv moon
for persisting effect, now resembled closely the former relationship to full moon
for the initial controls (compare Fig. 2 with Fig. 3C and 3C').
Since the observations in these experiments had been made only during 7 or
8 daytime hours, between about 9 AM and 5 PM, the monthly rhythm of the controls
could be considered as reflecting a lunar-daily variation in the orientational re-
sponse of the worms, when north-directed, to the ambient geophysical field, and
after magnetic field-reversal as a 180 -phase- shifted lunar-daily variation in
response.
DISCUSSION
The results of this study extend our knowledge of responses of planarians to
altered very weak horizontal magnetic fields to include another kind of response.
This one is a phase-shifting of a lunar rhythm by an abruptly reversed horizontal
vector. This response .appears to be independent of vector strength at least over
a range from about 1/3 to about 23 times the earth's local horizontal vector, the
range in this investigation. This response appears to relate geomagnetic vector
direction in some manner to phase angle in the biological lunar rhythm.
Fven by the end of 25 minutes following removal of the experimental fields
the relation between mean path and elongation of moon had displayed no tendency
in Figures 3( ' and 3( v would have exhibited no characteristic monthly pattern of
variation. Instead, a monthly variation of closely the same character is present
for the 20- and 25-minute response patterns following the 0.05- and 4.0-gauss
PHASE-SHIFTING A RHYTHM BY MAGNETISM 85
reversed fields. This pattern resembles, even in striking details in its form, the
monthly pattern of variation of the initial controls. Even amplitude is similar.
It is, however, 180 out of phase with the controls. The worms thus appear to
have superimposed on their initial state a fully comparable monthly pattern with
respect to full moon that as initial controls they had had with respect to new moon.
In other words, the experimentally reversed magnetic fields, whether 0.05- or
4.0-gauss, had, after the very different transient states during and immediately
following the reversed field, come to effect a common pattern of lunar-monthly
variation in response to the natural ambient geophysical field.
In a previously reported study (Brown, 1962) a 4-gauss horizontal magnetic
field parallel to the axis of N-directed planarians had abolished a distinct unimodal
monthly variation which was present when the worms were in the natural ambient
field. The current study indicates that a S-directed 4-gauss field, under com-
parable conditions, tends to convert the natural unimodal monthly variation in
orientational behavior at least initially into a bimodal one ( Fig. 3 A' ) , suggestively
a transitional state between the initial cycle and the 180-shifted, essentially uni-
modal one which ultimately appears following return of the worms to the natural
environment. At the same time this study indicates that far less conspicuous
transient alterations result from application of a 0.05-gauss reversed field, judging
from the general similarity between the relationships depicted in Figures 3A
through C. The weaker field appeared, therefore, to be the more efficient in
effecting the phase shift.
The slightly increased amplitude of the monthly variation evident immediately
following the 0.05-gauss field (Fig. 3B), and the initial delay in reaching the full
cycle range following exposure to the 4.0-gauss field (Fig. 3B'), suggest a
hypothesis that following exposure to horizontal vectors weaker than the earth's,
animals are transiently hypersensitive to the earth's vector, and following exposure
to vector fields stronger than the earth's, transiently hyposensitive.
The explanation of the mean monthly variation in the response to the 4.0-gauss
field when expressed as difference from response to the 0.05-gauss one, and its
gradual decay following removal of the experimentally reversed horizontal mag-
netic vector, have now become apparent. This reflected the difference in influence
on the monthly rhythm between the responses to the two strengths of experimental
fields. The immediate phase-shift in response to the 0.05-gauss field, together
with the initial, only partial, shift as response to the 4.0-gauss one, resulted in a
monthly variation in the difference between them (Fig. 1A). This difference,
though steadily diminishing during the first 15 minutes following removal of the
experimental fields (Fig. IB), did not essentially disappear until 15 to 25 minutes
had elapsed (Fig. 1C). The difference had practically vanished only after both
experimental groups came ultimately to stabilize with the same 180-shifted
monthly pattern.
Perhaps the most interesting and potentially most significant finding of this
study is the apparent association between phase angle of a spatial vector factor, the
horizontal component of terrestrial magnetism, relative to other contemporary
vector forces and the phase angle of a biological rhythmic variation. Although a
number of kinds of observations have suggested an existence of some common de-
nominators for the biological clock and biological compass mechanisms, this is the
86 FRANK A. HROXVX. JR. AND YOUNG H. PARK
first specific piece of experimental evidence that such a relationship may actually
exist. While much r\ idrnce has been advanced in support of the conclusion that
geographic orientation is influenced In phase-resettings of biological clocks, this
is the first evidence that a biological rhythm itself can have its phase reset by
altering the vector angle of any geographical field component.
The observed monthly variation in orientational tendencies of N-directed
planarians is a mosaic of the activities of numerous individual members sampled
from day to day from a very large population. The phase-reversal which is de-
scribed here had clearly become essentially fully effected for the 0.05-gauss worms,
even in time to be fully evident during the first 5-minute test assays of the worm-
samples from the population over the 7-month period of study. This is hardly
the type of behavior expected of an independent internal physico-chemical oscillator
system as it became phase-entrained to some altered relationship. There is, obvi-
ously, no time in the phenomenon to permit conventional physiological transients.
Rather, it is more plausibly like an abrupt reversal in the character of the response
of the experimentally treated worm population to an external cyclic geophysical
pattern. Hence, this capacity for virtually instantaneous reversal in rhythm phase
appears to constitute further suggestive evidence for extrinsic timing of biological-
clock systems.
SUMMARY
1. It has been shown that a 180 shift in the direction of the horizontal vector
of magnetism will effect a 180 shift in the phase of the monthly rhythm in geo-
graphical orientation in planarians.
2. The shift is essentially completed immediately when the reversed field has a
strength of 0.05-gauss, or about 1/3 the earth's natural horizontal vector strength.
3. When the experimentally reversed magnetic field has a strength of 4.0-gauss,
more than 20 times the earth's, the complete reversal of the rhythm requires as
long as 15 minutes, following the removal of the experimental fields, during which
time characteristic transients intervene.
4. Implications for the biological-clock problem of this demonstrated relation-
ship between vector direction of one geophysical component, relative to the others,
and phase relationship of a fundamental biological rhythm are discussed.
LITERATURE CITED
BROWN, F. A., JR., 1962. Response of the planarian, Dii(/cxiti. and the protozoan, l\inuuciium,
to very weak horizontal magnetic fields. Bin!. Hull., 123: 264-281.
BROWN, F. A., JR., 1963. An orientational response to weak gamma radiation. Biol. Bull., 125:
206-225.
llrowN, F. A., JR., 1965. Effects and after-effect* on planarians of reversals of the horizontal
magnetic vector. Nature (in press).
BROWN, F. A., JR., AND V. 11. I'AKK, 1965. Duration of an after-effect in planarians following
a reversed horizontal magnetic vector. Hint. Hull., 128: 347-355.
EFFECTS OF TEMPERATURE ACCLIMATION ON SOME ASPECTS
OF CARBOHYDRATE METABOLISM IN DECAPOD CRUSTACEA 1
JOHN MARK DEAN 2 AND F. JOHN VERNBERG
Duke University Marine Laboratory, Beaufort, North Carolina, and Duke University,
Durham, North Carolina
Temperature is one of the environmental factors to which the organism must
adjust if it is to exist successfully in its habitat. In temperate-zone forms the
severe temperature extremes of mid-wiuter and late summer may result in a shift
of metabolic processes, tending to compensate for these extremes. However,
tropical forms living in a relatively constant thermal environment do not have to
contend with such extremes and their metabolic processes may not show a com-
pensatory shift (Vernberg, 1962). Thus the temperature effects on an animal
may be reflected in its physiology. Past investigations of temperature effects on
populations have concentrated upon comparisons of rate functions such as oxygen
consumption, ciliary activity, heart beat, and thermal limits of tissues and/or
whole organisms (Bullock, 1955). It is to be expected that the ability to exist
at an environmental temperature is expressed in the physiological and biochemical
responses of the animal. The nature of these responses to temperature may vary
with species or stage of the life cycle. Thus, not only is there a variation in the
rate function of metabolic change with temperature adaptation, but the nature
of the metabolic reaction or pathway may be altered (Ekberg, 1958; Hochachka
and Hayes, 1962). The present research has been concerned with possible varia-
tions in carbohydrate metabolism with temperature acclimation. Several differ-
ent species of crabs have been studied, using physiological parameters such as
blood glucose, the total reducing sugar in the blood and hepato-pancreas glycogen
levels. Also included was a qualitative analysis of blood carbohydrates using
chromatographic techniques.
MATERIAL AND METHODS
Glucose oxidase (Huggett and Nixon, 1957) was used for the determination
of blood glucose and the classic Folin-\Yu method (1920) for the total reducing
sugars. Glycogen was determined by the phenol-sulfuric acid method of Mont-
gomery (1957). Chromatography of blood carbohydrates was done with ascend-
ing, descending and two-dimensional flow on Whatman #1 and #3 filter paper.
Various solvents were used, with the best resolution obtained with n-butanol, ethyl
alcohol, acetic acid and water in an 8:2:1:3 mixture by volume. The papers
were washed in the solvent system prior to spotting the unknown. Sprays for
the analysis of unknown carbohydrates included silver nitrate and sodium hydroxide,
1 Supported by National Science Foundation Grant G-12888 to F. J. Vernberg.
2 Present address : Biology Department, Pacific Northwest Laboratory, Battelle Memorial
Institute, Richland, Washington.
87
88
JOHN M. DEAN \\D F. JOMX VERNBERG
aniline hydrogen phthalate, iodine vapor, I'-anisidine HC1 and triphenyl-tetrazolium
chloride. Blood samples were collected from different sites in the various species
of crabs used: I 'en put/Untor. U. uihia.v and U. pitt/na.r were sampled in the
second segment proximal to the cheliped ; while Callinectes sapidus were sampled
from the sinus at the base of the fifth pereiopod and for Cancer irronilns, Libinia
einari/inata, Panopcns licrl'sth and J/rj///>/v mercenaria, directly from the heart.
Males only were used for analysis to reduce the possible effects of the hormonal
factors associated with the reproductive cycle in the female (Dean and Vernberg,
CHROMATOGRAPHIC PRESENCE ( + ) OR ABSENCE
OF CARBOHYDRATES IN BLOOD
Callinectes sapidus
Cancer i r r o r a t u s
Libinia emarginata
Menippe mercenaria
Panopeus herbst i i
Uca m i nax
(Early Spring)
Uca m inax
(Autumn)
Uca m inax
(10). "(18). (280)
Uca p u g i I a t o r
Uca pugi lator
(Early Spring)
Uca pugi lator
(Autumn)
Cancer magister 1
anD
Hemigrapsus nudus
Orconectes vi r i I is?
Ma Itotetraose
Maltotr iose
Maltose
Glucose
Meenakshi and Scheer
McWhinnie and Sailer
Galactose
Man nose
Fucose
TABI.K I
Galactan
Derivative
1964). For chromatography, the blood was deproteinized by heating in a boiling-
water bath for one minute and the supernatant fraction obtained after ceutrifuga-
tion was desalted (I)owex \( I-501-XX ) ; the resulting effluent was taken to dry-
ness, dissolved in water to give a concentration equivalent to about 20 micrograms
per microliter of dried material and standards were run with each unknown (Mc-
\Vhinnie and Sailer, 1'^iOj. l\ f and R g values were calculated for comparison
with values obtained by other workers. In acclimation experiments, other than
the chromatography, I ': pin/Hn/or were used. These animals were acclimated
to a given temperature lor a minimum of three weeks. They were kept under
a uniform 14 hours light and 10 hours dark photoperiod and the water was main-
TEMPERATURE ACCLIMATION IN CRABS 89
tained at a constant salinity of 30/{ c and changed every 36 hours on an 8 AM, 8
PM, 8 AM schedule. The diet consisted of Clark's fish pellets. This maintenance
procedure resulted in a very low mortality in the laboratory animals. For the
eyestalk experiments, the eyestalks were removed at their base and the wound
closed with a cold cauterizer.
30
o>
Q_
20
0>
o
ID
O
T3J
O
o
CO
10
o 21 Day Acclimated
Uca pugilator
+ 21 Day Acclimated
F uerto R ican Uca rapax
10
15
20
25
30
Temperature. C
FIGURE 1. Blood glucose in acclimated crabs.
RESULTS AND DISCUSSION
The qualitative chromatography of blood carbohydrates, as seen in Table I,
in seven species of crabs gave similar results. All species have maltotetraose,
maltotriose, maltose, galactose, glucose and a galactan derivative. Some differ-
ences occur in the appearance of mannose and lucose in some species. Mannose
is present in Menippe and early-spring Uca pugilator and possibly in Libinia,
autumn Uca mina.\- and Callinectes. Fucose is definitely present in Menippe and
possibly in Libinia and autumn Uca inina.i". Glucose-6-phosphate is known to be
present in the blood of these crabs from other work done in this laboratory. These
results compare favorably with those obtained by Hu (1958) for the shore crab,
JOHN M. I) KAN A.VD F. JOHN VERNBERG
Hcmi(jni[>sus nndns and Cancer, and the work of McWhinnie and Sailer (1960)
on the fresh-water crayfish, Orconcctcs. Fairbairn (1958), using disc chromatog-
raphy, has demonstrated trehalose in the tissues of several crustaceans. Using
colorimetric techniques, we detected trace amounts of trehalose in the blood of
several species and a higher amount was found in the blood of Libinia. However,
these results are quite variable. Samples of blood of three species of Uca ac-
climated to different temperatures have been analyzed by chromatography. No
qualitative differences could be seen in the blood carbohydrates.
Results of blood glucose and total reducing sugar levels of crabs acclimated to
different temperatures would indicate that the concentration of glucose in blood is
depressed at the lower temperatures (Fig. 1). A minimum of 15 individual sam-
ples was used in the determination of each point, and the figures show the mean
value and standard error. Blood glucose is usually 20-25% of the total reducing
sugar value of the blood. This ratio does not seem to vary significantly with
o>
cn
E
o>
i/i
O
35
30
25
20
15
o
o
10
Uca m i nax Accl i mated
90 Days
\
10
20
30
Temperature, C
FIGUKK 2. J! Idod glucose in acclimated crabs.
TEMPERATURE ACCLIMATION IN CRABS
91
30
o>
Q_
cr>
20
10
O
_0
CO
+ A
X
O T
A
V
0+
X
T
fi
10 20
Temperature, C
30
FIGURE 3. Blood glucose in crabs (X U. pugilator field animals, + U. pugilator 21
day acclimation, O U. minax 21 day acclimation, T U. ininax 90 day acclimation, A
U. rapax, CD U. pugnax),
acclimation. Also, a tropical species (Uca rapax), acclimated at the same tem-
perature as temperate species, has similar blood glucose values. Apparently labora-
tory acclimation had results similar to natural field conditions because 2 laboratory-
acclimated U. pugilator had a low blood glucose value, as did the newly emerged
crabs in early March. Short periods of acclimation to higher temperatures resulted
in a higher blood glucose level, and long-term acclimation to high temperature, as
in U. minax, showed an even more marked increase. However, U. minax shows
much the same response as U. pugilator (Fig. 2). Long-term acclimation, in this
case three months, resulted in a trend to temperature-dependent blood glucose
values. The level for field animals emerging early in the spring and acclimating
animals followed the patterns seen in U. pugilator.
Uca pugnax, a temperate-zone form, fits the range of blood glucose values for
the other species (Fig. 3) and U. rapax, which is a tropical species, is also in the
same general range. Thus, it may be seen that there is a general trend to low
92
.101 IX M. 1)K\\" AND F. JOHN VERNBERG
glucose ;it low temperature and an upward trend at higher temperatures.
The data indicate a plateau for blood glucose around the optimum temperature
range of the animal, which is a pattern similar to that seen in respiration experi-
ments (Vernberg, 1^59).
o>
Q_
O1
O>
un
O
<_>
13
O
o
o
CO
50
40
30
20
10
o
+ Blood Glucose in 10
Acclimated Animals
o B lood Glucose in 30
Acclimated Animals
10
Days
FIGUKK 4. Kffivt of f.-islin.u on MMM.I uhu-Mse in [7. fiitgilator.
TEMPERATURE ACCLIMATION IN CRABS
93
25
20
Q_
CD
15
oo
O
= 10
-o
O
o
CO
+ Blood Glucose in 10
Accl i mated Animals
o Blood Glucose in 30
Acclimated Animals
T
+
T
+
i
T
J+
1
5
10
Days
FIGURE 5. Effect of eyestalk removal on blood glucose in U. pngllator.
Qualitatively there is no major change in blood carbohydrates with acclimation.
However, there may be quantitative differences, as shown by the lower blood
glucose values obtained with animals acclimated to low temperatures.
We were interested also in the effects of diet and hormones in relationship to
the carbohydrate metabolism of the animal. Crabs were well acclimated for 21
days at 10 and 30. They were then fasted and sampled on days 0, 1, 5 and 10.
Unlike Libinia, which shows no change in blood sugars with fasting or eyestalk
removal (Kleinholz and Little, 1949), it may be seen in Figure 4 that the blood
glucose in the fasting 30 U. pugilator decreased consistently with time while the
fasted 10 animals were fairly constant. The hepato-pancreas glycogen levels
followed this same pattern.
Eyestalk removal during the intermolt stage will induce molting in the crab
except at lower temperatures where temperature acts as a molt inhibitor (Passano,
1960). During ecdysis, a period of high physiological activity, several dramatic
changes in the carbohydrate metabolism occur. To induce molting, eyestalks were
removed from 10 and 30 acclimated U. pugilator fed ad libitum. Samples were
taken on days 0, 1, 3, 5 and 10. Under these conditions, which initiate the molt
sequence of events, there is an extremely rapid drop in the blood glucose level of
the 30 animals (Fig. 5). This remains at a low level for a period of time and
then begins a slow increase. However, the 10 animals did not show this change
94 JOHN M. DEAN AND F. JOHN VERNBERG
in blood glucose level, did not molt, or initiate proecdysis, and had a high mortality
rate. There is no significant change in the hepato-pancreas glycogen values in
the 10 animals but the 30 crabs showed a typical buildup in hepato-pancreas
glycogen as molt approaches, and rapid decline with ecdysis.
The authors are grateful to Miss Rosemary McCarthy for her fine technical
assistance and the J. R. Clark Co., Salt Lake City, Utah for supplying the diet.
SUMMARY AND CONCLUSIONS
The preceding work on carbohydrate metabolism in Uca would suggest the
following :
First, with temperature acclimation there is no qualitative shift in carbohydrate
metabolic pathways, but rather there may be quantitative variations. Second, at
low temperature the animal reduces its energy output to a minimal level. This
may be related to the energy demands of the molt cycle. It would seem that even
though sufficient carbohydrate reserves are present at low temperature, there may
be variations in hormone levels which would affect the molt cycle. These physio-
logical characteristics correlate well with field observations and the general ecology
of the fiddler crab. However, generalities cannot be made for all Crustacea as
there are obvious differences between genera.
LITERATURE CITED
BULLOCK, T., 1955. Compensation for temperature in the metabolism and activity of Poikilo-
therms. Biol, Rev., 30: 311-342.
DEAN, J. M., AND F. J. VERNBERG, 1964. Variations in the blood glucose level of Crustacea.
Comp. Biochem. Physiol. (in press).
EKBERG, D. R., 1958. Respiration in tissues of goldfish adapted to high and low temperatures.
Biol. Bull., 114: 300-316.
FAIRBAIRN, D., 1958. Trehalose and glucose in Helminths and other invertebrates. Canad. J.
Zool.,36: 787-795.
FOLIN, O., AND H. Wu, 1920. A system of blood analysis Supplement 1. A simplified and
improved method for determination of sugar. J. Biol. Chem., 41: 367-374.
HOCHACHKA, P. W., AND F. R. HAYES, 1962. The effect of temperature acclimation on path-
ways of glucose metabolism in the trout. Canad. J. Zool., 40: 261-270.
Hu, A. S., 1958. Glucose metabolism in the crab Hcmigrapsus nudus. Arch. Biochem. Bio-
phys., 75 : 387-395.
HUGGETT, A. ST. C., A. \D D. A. NIXON, 1957. Enzymatic determination of blood glucose.
Biochem. J., 66: 12 P.
KLEINHOLZ, L. H., AND B. C. LITTLE, 1949. Studies on the regulation of the blood sugar in
crustaceans. I. Normal values and experimental hyperglycemia in Libinia emarginata.
Biol. Bull., 96: 218-227.
MEENAKSHI, V. R., AND B. T. SCIIEER, 1961. Metabolism of glucose in the crabs Cancer
magistri and IJciini/nipsnx nitdns. Comp. Biochem. Physio!., 1: 110-122.
McWniNNiE, M. A., AND SK. P. N. SALLER, 1960. Analysis of blood sugars in the crayfish
Orconcctes ririlis. Comp. Bun-hem. Physiol., 1: 110-122.
Md\ I(,()\IKKV, R., l ( >57. The (It-termination of glycogen. Arch. Biochem. Biophys. 67: 378-386.
I '.\- -A NO, L. M., 1960. ]. ueruture blockage of molting in I'ca puqnax. Biol. Bull..
118: 129-136.
VERNBERG, F. J., 1959. Studies on the physiological variation between tropical and temperate
zone fiddler crabs of the genus Ccn. II. Oxygen consumption of whole organisms.
liiol. Bull., 117: 163-184.
VERNBERG, F. J., 1962. Comparative physiology: Latitudinal effects on physiological properties
of animal populations. Ann. A'<v. Physiol., 24: 517-546.
PINOCYTOSIS OF PROTEINS BY OYSTER LEUCOCYTES l > -> 3 > *
S. Y. FENG
Department of Zoology, Rutgers, The State University, New Brunswick, N. J.
The term "pinocytosis" (cell drinking) was first introduced by Lewis (1931).
This same phenomenon, however, was observed earlier by Metchnikoff (1901) in
mammalian leucocytes in an aseptic exudate induced by a 10% gelatin solution,
and also by Edwards (1925) in amoebae when certain simple salts were added to
their culture medium. Later Mast and Doyle (1934) found that, in the presence
of albumin or calcium gluconate solutions, Amoeba proteus and a number of related
species also display pinocytic activities. After the publication of these papers,
pinocytosis was virtually unheard of for nearly 20 years. Recently this old subject
has been investigated with renewed vigor by using new techniques : e.g., electron
microscopy, fluorescence microscopy, interference microscopy, radioisotope and
fluorescent dye labelling, and serological methods. A brief review of the literature
reveals that pinocytosis has been demonstrated for mammalian cells, in tissue cul-
tures, such as polymorphs (Bessis and Bricka, 1952), macrophages (Lewis, 1931),
erythroblasts, normoblasts, reticulocytes and certain pathological erythrocytes
(Bessis and Breton-Gorius, 1957^), sarcoma cells (Lewis, 1937), ascites tumor
cells (Easty, Ledoux and Ambrose, 1956) and HeLa cells (Rose, 1955) ; for
protozoa such as A. proteus (LAjys, 1937), Chaos chaos (Holter and Marshall,
1954; Brandt, 1958), Plasmodininiopliurae and P. bcrghei (Rudzinska and Trager,
1957, 1959) ; and for blood element^ of invertebrates, e.g., elaiocytes of the coelomic
fluid of echinoderms (Holter, 1959) and phagocytes of planarians (Rosenbaum and
Rolon, 1960). V*
Oyster leucocytes are known to ingest a variety of participate materials (Yonge,
1926; Takatsuki, 1934; Stauber, 19*0; Tripp, 195Sa, 1958b, 1960; Feng, 1962).
In the present study, the in vivo and in vitro uptake of proteins by oyster leucocytes
was demonstrated by using serological techniques and fluorescence microscopy.
MATERIALS AND METHODS
*
1. Oysters, aquaria and sea ivater
The oysters and sea w-ater used in this study were collected from the Navesink
River, near Red Bank and trie Shrewsbury River at Highlands, New Jersey, re-
1 Part of a thesis submitted to the graduate faculty of Rutgers, The State University, in
partial fulfillment of the requirements for the degree of Doctor of Philosophy.
2 This investigation was supported in whole by Public Health Service Research Grant
AI-00781, from the National Institute of Allergy and Infectious Diseases of the National
Institutes of Health.
3 In the oyster the terms amebocyte, leucocyte, and phagocyte are used interchangeably, as
suggested by Stauber (1950).
* Present address : Oyster Research Laboratory, Rutgers, The State University, New
Brunswick, N. J.
95
96 S. Y. FENG
spec-lively. I'yrex battery jars, measuring 25 X 25 cm., were used as aquaria to
hold oysters. The oysters were kept m sea water of 20%e throughout the experi-
ment. Constant aeration was maintained in each aquarium. Water was changed
at least twice dailv.
2. Preparation of ovsters (or injection and bleeding
Exposing the heart for injection and bleeding was achieved by following the
established procedure of Feng (1965).
3. Preparation, injection, and detection of inocnla
a. Bovine hemoglobin solution
A 5 % crystalline bovine hemoglobin solution was prepared in a diluent of oyster
plasma which was drawn and pooled from 10 oysters. Desired amounts of this
solution were injected into oysters via the ventricular route.
The reduction of bovine hemoglobin from the blood stream by the oyster was
followed colorimetrically by sampling the heart blood at appropriate intervals over
a period of 154 minutes. The presence of bovine hemoglobin within the leucocytes
after injection was detected visually by the pink coloration of the washed sedi-
mented blood cells.
b. Diphtheria antitoxin
Horse antibody to diphtheria toxin, kindly supplied by Dr. R. J. DeFalco.
Director of the Serological Museum, Rutgers, The State University, was injected
into 10 oysters in volumes of 0.2 ml. per animal (3125 units per ml. of antiserum).
Pooled blood samples were taken from the oysters in the amount of 0.2 ml. per
oyster at 10 minutes, 1, 2, 4 and 8 hours. Oyster leucocytes were separated from
the plasma by centrifugation and washed in several changes of sea water. The
cells were ruptured by grinding them with fine sand and the extract was recon-
stituted to 2.0 ml. with O.S5'/f saline. The sand was removed by centrifugation.
The presence of the diphtheria antiserum in both the plasma and leucocyte
saline extract was detected by reacting them with diphtheria toxoid, using a modi-
fied procedure of Ramon titration. The procedure of ordinary Ramon titration
(Boyd, 1956) consists of mixing constant dilutions of toxoid with varying dilu-
tions of antiserum or vice versa. The amount of toxoid which gives most rapid
flocculation with one standard unit of antiserum is first determined. The amount
is designated as the Lf unit. Then unknown antisera can be titrated against this
standardized toxoid. The time required for the first flocculent precipitate to occur
is referred to as Kf. or flocculation time. The modified procedure devised for this
work is carried out under the condition that the Lf units of both the toxoid and
antiserum are known. When materials containing unknown units of toxoid or
antiserum are added to the above system, the flocculation time will change ac-
cordingly.
I'erhaps the points made above are best illustrated in the following example:
Till..- No. 1234
Toxoid (50 Lf /ml.) 0.5 ml. 0.5 ml. 0.5 ml. 0.5 ml.
\ntisc rum (312.5 units/ml.) 11.00 ml. 0.08ml. 0,10ml, 0.12ml.
Kf (minutes) 35
PINOCYTOSIS BY OYSTER LEUCOCYTES ( J7
Tube No. 2 is the first one to show the flocculent precipitate after 35 minutes incu-
bation at 40 C. If 0.5 ml. oyster plasma containing an unknown amount of anti-
serum was mixed with the toxoid in each of the above four tubes and then the usual
amounts of antiserum added, there could be the following possible consequences:
the Kf of Tube No. 2 could be prolonged, shortened or unchanged depending on
the amount of antiserum contained in the oyster plasma; or Tube No. 3 could be
the first one to show the flocculent precipitate. If the latter case took place, the
unknown might be solved as follows: 50 Lf X 0.5 + X == 312.5 X 0.10, where X
represents the unknown Lf units contained in 0.5 ml. of oyster plasma.
c. Rhodamine-labelled proteins
Conjugation of crystalline human gamma globulin, albumin fraction V and
Li nut Ins serum with Lissamine Rb 200 was carried out as specified by Chadwick,
McEntegart and Nairn (1958). The conjugated proteins were brought to pH
7.8 and normal tonicity by dialyzing overnight against filtered sea water (20%e).
The final concentration of these solutions was 2.5 gm. per 100 ml.
The fluorescence equipment used in the present study is manufactured by
Reichert. It consists of a regular monocular microscope, with a high pressure
mercury arc (HBO 200) as source of excitation. When viewed under the UV
microscope with Schott BG-12 (3 mm.) and Corning-5840 as primary filters and
Eastman Kodak WA-15 as secondary filter, the rhodamine conjugates exhibit a
brilliant orange fluorescence which is readily distinguished from the blue-green
intrinsic fluorescence of oyster leucocytes and other tissues.
RESULTS
1. Bovine hemoglobin
Three oysters (A, B and C) were injected with 0.3, 0.2 and 0.15 ml. of a 5%
bovine hemoglobin solution, respectively. The different rates of disappearance of
hemoglobin from the heart blood shown by the three oysters reflect differences in
the amount of inoculum received, since the three oysters were comparable in size
(Fig. 1). According to Figure 1, 130, 63 and 48 minutes were required to reduce
50% of the injected hemoglobin by oysters A, B and C, respectively.
It was noticed that nearly all samples of oyster whole blood taken 30 minutes
after injection contained some pink leucocytes. The leucocytes retained their pink
coloration even after several gentle washings in filtered sea water.
2. Diphtheria antitoxin
Since the ionic concentration and other constituents of oyster plasma and
leucocyte saline extract are probably quite different from those of mammalian sera,
a series of controls designed to test the effects of oyster plasma on the toxoid-
antitoxin system was first initiated. The result (Table I) indicates that adding
0.5 ml. of 0.85% saline to Control A increases the Kf almost 7\% (line B). Addi-
tion of either oyster plasma or leucocytes saline extract to the toxoid-antitoxin
system greatly retards the reaction ; in certain instances the Kf is 2 to 5 times
longer than the control (compare B with C; E with F and G). Superficially, the
98
S. Y. FENG
inhibitory effect of oyster plasma appears to be stronger than that of leucocyte
saline extract. The importance of this difference will remain unanswered until
information concerning the precise protein content, ionic composition and other
constituents in a unit volume of oyster plasma and leucocyte saline extract becomes
100-
8 80
DO
S 60
40
o
oo
.0
I 20
0?
x>
10
oyster A
B o
CA
20 40
60 80 100
Minutes
120 140 160
FIGURE 1.
The reduction of intracardially injected bovine hemoglobin from the heart blood
of three oysters.
available. The data also suggest that the Kf is a function of the concentration of
reagents. The toxoid of Controls I',, C and D contains 25 Lf units, while the anti-
scrum of Control !'.. !' and G is 125 Lf units. Consequently, the Kf for the latter
group is 3 to 12 times shorter than that of the former group. 1 lenee. wherever a con-
siderable shortening of Kf occurs in the experimental group, as contrasted with the
proper control, it is implied that this shortening of Kf is probably due to the pres-
PINOCYTOSIS BY OYSTER LEUCOCYTES
99
ence of an unknown amount of Lf units in the oyster plasma and leucocyte saline
extract.
Based upon the above considerations, it is found that the presence of diphtheria
antiserum in the oyster plasma could be detected 10 minutes to four hours after
the injection, while in the leucocyte saline extract it probably lasted two hours.
However, the subsequent negative results do not necessarily suggest that the
injected material is degraded but may merely indicate that the concentration of
this material becomes too low to be detected by this procedure.
TABLE I
The detection of diphtheria antiserum (horse) in oyster plasma and leucocyte saline
extract, expressed in terms of flocculation lime (Kf) by using a modified
Ramon titration procedure
Flocculation time (Kf) in minutes
System
10 min.
1 hr.
2 hr.
4 hr.
8 hr.
Remarks
Experimental samples
A. T-A
35
,
T (constant) = 25
B. T-S-A
60
Lf/0.5 ml.
C. T-Op-A
120
-
53
65
*
A (variable) = 312.5
D. T-O1-A
68
48
71
65
Lf/ml.
E. A-S-T
5
A (constant) = 125
F. A-Op-T
25
5
30
Lf/0.04 ml.
G. A-O1-T
20
**
8
T (variable) = 300
Lf/ml.
T, A, S, Op and Ol represent diphtheria toxoid, diphtheria antiserum, saline, oyster plasma
and oyster leucocyte saline extract, respectively. The saline used is a solution of 0.85% NaCl.
* No reaction was noticed after three hours.
** Sample lost.
3. Rhodaniine-labcllcd proteins
a. The effect of concentration on the uptake of rhodamine-labelled human gamma
globulin by oyster leucocytes
Four rhodamine-labelled human gamma globulin solutions : 2.5, 0.25, 0.025
and 0.0025 gm.%, were used in the experiment. One drop of the above solutions
was mixed with four drops of oyster blood on a slide. The drops of protein solu-
tion and oyster blood were delivered by a tuberculin syringe with a 30-gauge needle.
Thus, on the slide the leucocytes were exposed to rhodamine-labelled human gamma
globulin solutions with the following final concentrations : 0.5, 0.05, 0.005 and
0.0005 gm.%. After the leucocytes were exposed to the solution for a specified
period (5, 15, ... 60 minutes), the excess protein solution was removed by sev-
eral gentle washings with filtered sea water. The preparation was sealed with a
Vaselined coverglass and viewed under the UV microscope. Each sample con-
sisted of three such preparations. The number of leucocytes containing orange-red
100
S. Y. FENG
fluorescent dots in at least 100 leucocytes was used to calculate the per cent pinocy-
tosjs by the leucocvtes. 1'oth e\|)eriinents were carried out at 23 C.
The results shown in Figure 2 surest that in both experiments the leucocytes
require longer time to take up protein from a less concentrated rhodamine-labelled
human stamina ulobulin solution than from a more concentrated solution. It is
noticed that there are differences between experiments but the general order of
concentration effect on the rate of uptake of the protein solution by leucocytes is
consistent. Kor instance, to reach the level of 20% pinocytosis by the leucocytes
lOOi Effect of concentration
5xlO"'gm%
-2
n5xlO gm%
Exp. A 23 C.
A5xl6 gm%
-4
o5xl(Tgm%
5xlO~ gm%
-2
5xlO gm%
-3
gm%
-4
oSxIO gm%
10 20 30 40 50 60
Minutes
I'll,! R] The effect of concentration and time of exposure on the pinocystoMs of rliod-
amine-labelled human gamma ^lohulin l>y oyster K-ucdcyte.s. I ; ,acli jioint on the .uraph rrprcM-nt>
the median of three samples.
PINOCYTOSIS BY OYSTER LEUCOCYTES 101
in Experiment A, 2, 15 and 25 minutes are required for 0.5, 0.05 and 0.005 gm.%,
respectively; for 0.0005 gm.%, less than 5% of the leucocytes showed pinocytosis
at the end of 50 minutes. In Experiment B for comparable concentrations of pro-
tein solution, the relative rate of uptake by the leucocytes is in general lower than
that of Experiment A, i.e., 5 and 22 minutes for 0.5 and 0.05 gm.%, respectively.
Also at the end of one hour less than \5%. and 5% of the leucocytes showed pinocy-
tosis in 0.005 and 0.0005 gm.%. Efforts were made to render conditions as com-
parable as possible in the two experiments. However, the number of leucocytes
per drop of oyster blood as delivered by the tuberculin syringe with a 30-gauge
needle was not determined for the two experiments. It is suspected that some
of the differences in the rate of uptake in the two experiments might result from
unequal numbers of leucocytes in the drops of oyster blood used.
b. The effect of temperature on the uptake of rhodamine-labelled human gamma
globulin by oyster leucocytes
Two experiments were performed at 10 and 24 C., respectively. In con-
ducting the experiment at 24 C., the experimental procedure was similar to that
of Experiment A and B in the above study. For the experiment carried out at
10 C., special procedures were followed in order to maintain the leucocytes, in-
oculum and instruments used in this experiment at the same temperature. The
temperature of a refrigerator was adjusted so that the temperature was 10 C. on
the bottom shelf where the inoculum and a tuberculin syringe with 30-gauge needle
were stored overnight. Fresh oyster heart blood was obtained by bleeding the
animal at room temperature. Four drops of oyster blood were placed on each of
the 15 slides. They were immediately stored in the refrigerator in a moist chamber
to prevent excessive evaporation. At the end of 30 minutes, one drop of 2.5 gm.%
rhodamine-labelled human gamma globulin was added to each of the 15 leucocyte
preparations. At each preclesignated time interval, three leucocyte preparations
were removed from the refrigerator, washed, sealed and examined as described for
Experiments A and B reported above.
Figure 3 indicates that the uptake of the rhodamine-labelled human gamma
globulin (0.5 gm.%) by the leucocyte is considerably faster at 24 than at 10 C.
In order to attain the level at which 50% of the leucocytes show pinocytosis, 12
and 28 minutes were required for the leucocytes held at 24 and 10 C, respectively.
c. Distribution of rhodamine-labelled proteins in the tissue of oysters
Three groups of oysters (A, B and C), each consisting of 8 oysters, were used
for the injection of rhodamine-labelled human albumin, human gamma globulin
and Lunnlus serum protein, respectively. Each oyster was injected with 0.2 to
0.4 ml. of the above labelled proteins. A fourth group (D) with 8 uninjected
oysters served as a control. The experiment was performed with the temperature
ranging from 18 to 20 C. Sampling was made at the following intervals: 15
minutes, 1, 2 and 4 hours, and 1, 2, 4 and 6 days. At the above intervals, four
oysters, one from each of the four groups, were sacrificed by removing the shell.
The whole oyster was cut into three pieces through the following regions : oral
hood, visceral mass and adductor muscle. These pieces of oysters were wrapped
102
S. Y. FENG
separately with aluminum foil, dropped into liquid nitrogen for quick freezing and
-lured iu the refrigerator at '.. to be sectioned with a freezing microtome.
The sections placed on glass slide> were fixed briefly with lO^o formalin in sea
water. They were then dehydrated in three changes of dioxane of four minutes
each and mounted in non-fluorescent medium. The distribution of fluorescent
proteins in tissues was ascertained by noting (1) the presence or absence of inocu-
lated substances free or pinocytosed in selected lumina (blood vessels, intestine,
digestive diverticulum. etc. ), and (2) migration of protein-laden leucocytes through
various epithelia.
ioo
80"
60-
" 40-
o
.1 20-
Q_
Effect of temperature
5xlO~ l gm%
24 C.
10 C.
10 20 30 40 50
Minutes
FicukK 3. The effect ot' temperature and time of exposure on the pinocytosis of rhodamine-
labelled Inmian gamma globulin by oyster leucocytes. Each point on the graph represents the
median of three samples.
Regardless of the fact that the inocula consisted of three different protein so-
lutions. no outstanding differences were found in their distribution or in the subse-
quent elimination of the inoculated materials from the oyster. Thus, unless other-
wise noted, the following results apply to all three inocula. The blood in the
arterial and venous systems (anterior aorta, posterior aorta leading to the adductor
muscle, hlood spaces in the muscle, small arteries in the visceral mass, blood spaces
immediately adjacent to the stomach, intestine, style sac and rectum, sinuses in the
mantle, medial gill axis vein and lateral palliobranchial veins) appeared to be filled
with the labelled proteins 15 minutes after intracardial injection. At no time
during the experiment were labelled protein^ detected in the circumpallial arteries.
PINOCYTOSIS BY OYSTER LEUCOCYTES 103
In the subsequent samples, the general pattern of distribution of the labelled
protein was essentially similar to that of the 15-minute sample described above.
The only noticeable change was that the amount of free labelled proteins in the
lumina of blood vessels and spaces decreased with time ; this is indicated by the
gradual reduction of orange-red fluorescence in these areas. Concurrently with
the above observation, it was noticed that some of the labelled proteins outlined the
blood spaces as though adsorbed to the cells delimiting these spaces. The labelled
materials were found to be pinocytosed by leukocytes in the peri-intestinal region
within one hour post-injection. Migration of the protein-laden leucocytes across
the arterial wall was not observed in all samples. However, migration of protein-
laden leucocytes across the epithelia of stomach, intestine, rectum, digestive
diverticula and mantle facing the palp was first noticed 15 minutes after injection
of labelled human gamma globulin. This process did not commence in the oysters
inoculated with labelled human albumin and Limn I us serum protein until two
hours post-injection. Rejecta and dejecta collected from the aquarium 24 hours
post-injection showed numerous leucocytes containing rhodamine-labelled proteins.
This observation constitutes further evidence for the elimination of some of the
injected protein solutions. Epithelial linings of mantle facing the shell and promyal
chamber were only occasionally used by the protein-laden leucocytes as exits.
No protein-laden leucocytes were observed to traverse the wall of gonoducts and
nephridial tubules. Protein-laden leucocytes were also seen in the external lining
of the heart and the parietal pericardium. Although protein-laden leucocytes were
only very rarely seen in the lumina of stomach, intestine, digestive diverticula and
rectum, the observation that large numbers of protein-laden cells were found in
the dejecta has led the writer to believe that the rare occurrence of such cells in
these regions might be due to the fast emptying time of the digestive tract and the
concentration represented by the formation of dejecta.
DISCUSSION
The distribution and the sites of elimination of the injected rhodamine-labelled
proteins in oyster tissues in general do not differ significantly from those obtained
by the injection of other participate materials (Stauber, 1950; Tripp, 1958a, 1958b,
1960). Only the wide distribution of the labelled proteins and the earlier com-
mencement of migration of protein-laden leucocytes were in contrast with the find-
ings of Stauber and Tripp. For example, migrations of protein-laden cells were
first encountered in the epithelia of stomach, intestine and digestive diverticula 15
minutes to two hours post-injection (18 to 20 C.), whereas the process in the
same area was observed 8 days post-injection in oysters injected with India ink
at 12 to 21 C. (Stauber, 1950) and 2 to 5 days in oysters injected with yeast
cells and vegetative Bacillus mycoides at 17 1 C. (Tripp, 1960). The evidence
indicates that migration of host leucocytes through epithelial surfaces is a normal
physiological process. However, under experimental conditions, this process could
be accentuated or retarded, depending on the size and number of particles phago-
cytosed or pinocytosed by the leucocytes and the susceptibility of particles to intra-
cellular digestion. Lack of protein-laden leucocytes migrating through the arterial
wall could be ascribed in part to the relatively early wide distribution of the
104 S. Y i 1'NG
labelled proteins to the terminal branches of the circulatory system and, therefore,
occlusion of the major vessels, if it occurs, is probably very transient.
On the basis of the preseni findings and observations made by other investi-
gators, pinocytosis as displayed '>> various tissue cells and certain protozoa is now
well established. In the oyster, the pinocytic activity of leucocytes appears to be
primarily defensive, since protein-laden leucocytes are seen to traverse the
epithelium of the mantle and intestine on their way to exterior. In P. lophnrac
and P. bcnjhci. pinocytosis is a means of securing nutrient (Rudzinska and Trager,
1957, 1959). However, the significance of this process is still unclear in amoebae
and malignant cells. Lewis (1931) assumed that digestion occurs within the
pinocytosis vacuoles of amoebae. Recent studies indicate that low molecular
weight sub>taiices. e.g., glucose and methionine, carried inside the amoebae by
pinocytosis are probably utili/.ed ( Chapman- Andresen and Holter, 1955; C'hap-
man-Andresen and I'rescott. 105f>), while the fate of high molecular weight ma-
terials, e.g., proteins, is still unknown. In the free-living amoebae, such as C.
chaos, possessing a trait such as pinocytosis probably enhances the survival of the
species, especially during the period when the external environment becomes hyper-
tonic to the amoeba's "milieu interieur." Hence, it is possible that pinocytosis
in the free-living amoeba could be employed as a defense mechanism against de-
hydration. Parasitic amoebae, on the other hand, are bathed constantly in a me-
dium of tissue debris, red cells, bacteria and plasma, and one may infer that these
organisms enrich themselves by employing pinocytosis and phagocytosis simul-
taneously in securing both soluble and participate materials in the abscess. In
conclusion, pinocytosis may occur as a means of defense, of obtaining nutrients or
as a cytopathological manifestation of malignant cells.
The author is deeply indebted to Dr. L. A. Stauber for his numerous sugges-
tions, helpful criticisms and generous support of this work. Special thanks are
due to the late Professor T. |. Murray, and Drs. M. Solotorovsky and G. Kemp
of the Department of bacteriology for their cooperation in the use of freezing
microtome and UV microscope.
SUMMARY
In vivo and in vitro studies indicated that bovine hemoglobin, diphtheria anti-
serum, rhodamine-labelled human gamma globulin, human albumin fraction V and
Liinuliis serum proteins were pinocytosed by oyster leucocytes. The presence of
the various proteins within the leucocytes was detected by visual inspection of the
washed sedimented leucocxte^, serological techniques and fluorescence microscopy.
When the proteins were injected into the living oyster via the ventricular route,
epithelial surfaces to the exterior. The rate of in vitro uptake of rhodamine-
labelled human gamma globulin bv the leucootcs was a function of the ambient
temperature and the concentration of the protein solution in which they were
bathed.
LITER XTl'KK <TI I.I i
BESSIS, M.. \M> M. BRICKA, l''5J. Aspect dynamiqedes cellules <lu sang. Son etude par la
microcinematographie en omtraste <le phase. AYr/ir d'hematologic, 7: 407-435.
PINOCYTOSIS BY OYSTER LEUCOCYTES 105
BESSIS, M., AND J. BRETON-GORIUS, 1957. Iron particles in normal erythrohlasts and normal
and pathological erythrocytcs. /. Bio{>hys. Biochcm. Cytol., 3: 503-504.
Bovn, W. C., 1956. Fundamentals of Immunology. 3rd edition, Interscience Publishers, Inc.,
New York.
BRANDT, P. W., 1958. A study of the mechanism of pinocytosis. E.\-p. Cell Res., 15: 300-
313.
CHADWICK, C. S., M. G. MCNTEGART AND R. C. NAIRN, 1958. Fluorescent protein tracers,
a simple alternative to fluorescein. Lancet, 274: 412-414.
CHAPMAN-ANDRESEN, C., AND H. HOLTER, 1955. Studies in the ingestion of C 14 glucose by
pinocytosis in Chaos chaos. Exp. Cell Res. (Suppl.), 3: 52-63.
CHAPMAN-ANDRESEN, C., AND D. M. PRESCOTT, 1956. Studies on pinocytosis in the amoebae
Chaos chaos and Amoeba proteus. C. R. Trav. Lab. Carlsberg, 30: 75-78.
EASTY, D. M., L. LEDOUX AND E. J. AMBROSE, 1956. The action of ribonuclease on neoplastic
growth. III. Studies by interference microscopy. Biochiin Biophys. Acta, 20: 528-
537.
EDWARDS, J. G., 1925. Formation of food-cups in Amoeba induced by chemicals. Biol. Bull.,
48:236-239.
FENG, S. Y., 1962. The response of oysters to the introduction of soluble and particulate
materials and the factors modifying the response. Dissertation Abstract, 23(6) : 2099-
2100.
FENG, S. Y., 1965. Heart rate and leucocyte circulation in Crassostrea mrginica (Gmelin).
Biol. Bull, 128: 198-210.
HOLTER, H., 1959. Pinocytosis. In Internat. Rev. Cytol., edited by G. H. Bourne and J. F.
Danielli, 8:481-504.
HOLTER, H., AND J. M. MARSHALL, JR., 1954. Studies in pinocytosis in the amoeba Chaos
chaos. C. R. Trav. Lab. Carlsberg, 29: 7-27.
LEWIS, W. H., 1931. Pinocytosis. Bull. Johns Hopkins Hosp., 49: 17-27.
LEWIS, W. H., 1937. Pinocytosis by malignant cells. Amcr. J. Cancer, 29: 666-679.
MAST, S. O., AND W. L. DOYLE, 1934. Ingestion of fluid by Amoeba. Protoplasma, 20: 555-
560.
METCHNIKOFF, E., 1901. L'immunite dans les Maladies Infectieuses. Masson et Cie, Paris.
ROSE, G. G., 1955. A varient pinocytic cell (Vp of Gey's strain HeLa) produced and stimu-
lated by human serum nutrient. Texas Rep. Biol. Med., 13: 475-489.
ROSENBAUM, R. M., AND C. I. ROLON, 1960. Pinocytosis in phagocytes of planarians. Anat.
Rec., 137: 389.
RUDZINSKA, M. A., AND W. TRACER, 1957. Intracellular phagotrophy by malaria parasites:
an electron microscope study of Plasmodimn lophurae. J. Protosool., 4: 190-199.
RUDZINSKA, M. A., AND W. TRACER, 1959. Phagotrophy and two new structures in malaria
parasite Plasmodimn berghci. J. Biophys. Biochem. Cytol., 6: 103-112.
STAUBER, L. A., 1950. The fate of India ink injected intracardially into the oyster, Ostrea
virginica Gmelin. Biol. Bull, 98: 227-241.
TAKATSUKI, S., 1934. On the nature and functions of the amoebocytes of Ostrea cdulis.
Quart. J. Micro. Sci., 76: 379-431.
TKIPP, M. R., 1958a. Disposal by the oyster of intracardially injected red blood cells of
vertebrates. Proc. Nat. Shellfish. Assoc., 48: 143-147.
TRIPP, M. R., 1958b. Studies on the defense mechanism of the oyster, Crassostrea virginica.
J. Parasitol., 44(4, sect. 2) 35-36.
TRIPP, M. R., 1960. Mechanisms of removal of injected microorganisms from the American
oyster, Crassostrea znrginica (Gmelin). Biol. Bui/., 119: 273-282.
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Ostrea edulis. J. Mar. Biol. Assoc., 14: 295-386.
ACTIVE MOVEMENTS AND OTHER ASPECTS OF THE BIOLOGY OF
ASTICHOPUS AND LEPTOSYNAPTA (HOLOTHUROIDEA) 1
PETER W. GLYNN
Institute f Marine Biology. University of Puerto Rico,
Wayaguez, 1'ncrto Rico
The ability of certain benthic sea cucumbers to execute relatively rapid move-
ments has not been gem-rally recognized or given adequate treatment in compre-
hensive accounts of the Holothuroidea (e.g., Ludwig, 1892; Cuenot, 1948; Hyman,
1955). In some bathypelagic species the performance of rapid progressive move-
ments is regarded a normal means of locomotion. Ludwig (1892) and Hansen and
Maclsen (1956) have noted the remarkable swimming movements, first observed
by M. Sars (1868), of Juilliyplotcs natans (=Stichof>us natans), an aspidochirotid
of the typically deep-sea family Synallactidae. Gilchrist (1920, p. 381) observed
that ". . . some of the Holothurians procured in deep water off the South African
coasts have the power of swimming about freely in the water by an undulatory
movement of the body " He further surmised that ". . . such deep-sea
Holothurians do not bury themselves in the soft mud of the floor of the ocean,
but flit more or less readily over its surface." More recently, Hansen and Madsen
(1956, p. 55) have suggested, "Probably a powder of swimming, though often
awkward, may be attributed to a considerable number of Holothurians of the
family Psychropotidae within the order Elasipoda and of the genera Bathyplotes
and Paelopatides within the Synallactidae of the order Aspidochirota." These
authors remarked that of the known bathypelagic holothurians, Galatheathnria
uspera is probably the best adapted for active swimming, which in this species is
effected through undulatory movements of the lateral brim much as in the swim-
ming of the cuttlefish, Scf>ia. The elasipodid, Bcnthodytes typica, with a wide
brim all around the body, is also well adapted for swimming.
1 The portion of the study dealing with Astichopus was supported by National Science
Foundation Grant GB-888; observations on Lcptosynapta were made by the author while
employed with the California Cooperative Oceanic Fisheries Investigations. Appreciation is
expressed for the aid rendered by the following persons and institutions: Charles E. Cutress,
Smithsonian Institution, \Yashington, D. C., who supplied information on the swimming be-
havior of Astichopus and made available pertinent literature; David L. Fawson, also of the
Smithsonian Institution, who made available- pertinent literature and reviewed the manuscript;
Alfred II. Hummel, SCUBA instructor at K'anu \ \\\- Force Base, Aguadilla, Puerto Rico, who
assisted in the collrclion of specimens of Astichopus; Frank Fernandez, Research Assistant,
Institute of Marine Biology, who helped with tin- fit-Id and laboratory studies; John Shoup,
Bernice I'. Bishop Muslim, Honolulu, Hawaii, who helped with certain phases of the be-
havior studies; Stan \Yiinherh-y, Geology Section, University of Puerto Rico, Mayagiiez, who
aided in the analysis of sediment samples; I.uis M. Quiiiones-Rodriguez, Department of
1'hy.sics, I'niversity of I'uerto Rico, Mayagnex, who .supplied monochromatic lamps and fdters.
Credit is also due Elisabeth Deicliniann, Museum of Comparative Zoology, Harvard University
and Kenneth R. Jl. Read, Division of General Education, Boston University, for criticizing
the manuscript.
106
ACTIVE HOLOTHURIAN MOVEMENTS 107
Of the typically bottom-living, non-pelagic sea cucumbers, only a small number
of species were known to execute relatively rapid movements. All of these species
are members of the family Synaptidae in the order Apodida. As originally re-
ported by Nutting (1919), and quoted by Fisher in Deichmann (1926), Euaplu
lap fa can swim to a limited extent. Costello (1946) has described well the
active, scissor-like movements of the young of Leptosynapta albicans ( = in!ntcrcns),
as first reported briefly by Clark (1907, p. 63). Recently, Hoshiai (1963) has
observed undulatory swimming in the young of Ldbidoplax dnhia.
The quick swimming movements observed in adults of the aspidochirotid
Astichopits multifidus and Leptosynapta albicans are documented for the first time
in the present communication. Further, a description of some other kinds of
locomotory movements performed by Astichopits, which were formerly unknown
in the Holothuroidea, is included in this paper. Also, other aspects of the biology
of Astichopits are investigated in relation to the species' active movements, viz.
the nature of its habitat, the reactions elicited as a result of alterations of the
immediate environment (for example mechanical disturbances, temperature, light,
salinity), and its toxicity. A description of the sinusoidal swimming behavior of
MATERIALS
Astichopits nntltifidns (Sluiter. 1910) is a member of the order Aspidochirotida ;
members of this group are characterized by possessing disk-shaped tentacles and
respiratory trees. Examination of the structure of the gonad demonstrated that
it occurs as two tufts, thus confirming that the species does belong to the family
Stichopodidae (Deichmann, 1954). Astichopus, a monotypic genus in the West
Indies, is easily recognized because it is very large and soft, with both dorsum
and ventrum uniformly covered by hundreds of tube feet ; the dorsal tube feet are
papillate (Figs. 1 and 4). The dorsum of all specimens examined was some shade
of brown or gray, and exhibited a variable color pattern. Two individuals had
a chocolate brown dorsum with numerous small (ca. 1 cm. diameter) scattered
white spots ; the ventrum was also chocolate brown. Several specimens had a
light brown dorsum, and one of these possessed in addition three large (3-5 cm.
diameter), evenly spaced, chocolate brown spots. Lighter colored individuals
tended to have a white ventrum. The tube feet and papillae were light in color,
usually a translucent light yellow or light brown. Undisturbed, crawling Asti-
clwpus demonstrated a range in total length of 29-46 cm. Specimens observed
by Clark (1933) were somewhat larger, at least 45 cm. in length. Aggregates of
numerous minute grains and scattered C-, S-. or O-shaped calcareous particles
occur in the body wall (Deichmann. 1954). Three of the specimens collected in
Puerto Rico and used as material in this study have been deposited in the Smith-
sonian Institution. U. S. National Museum (Number E-10325).
Few specimens of Astichopits have been collected previously; the largest
number reported were brought up in trawl hauls made on the Campeche Bank
in the Gulf of Mexico. According to H. Hildebrand (quoted in Deichmann, 1954),
this species is an abundant form in this region. Several specimens were also col-
lected at Port Antonio, Jamaica, by Clark (1933). Since these earlier occurrences,
no other specimens have been reported from Jamaica (Fontaine, 1953). This
108
PETER W. GLYNN
species has been reported I'rom . oilier localiu in the tropical western
Atlantic, namely at Tortugas. Florida ( I )eichinann, 1963); the specimens found
in Puerto Rico constitute a new record for this region. Because a dense popula-
tion of this comparatively rare .species has been discovered in Puerto Rico, an ac-
count of the habitat is given in the next section.
Leptosynapta ullucans ( Selenka. 1S67), a well known California!! sea cucumber,
belongs to the order . \podida. a group wholly lacking tube feet, and to the family
FIGURE 1. Underwater photograph of Astichopits nntltifidits at the edge of a bed of the
seagrass, Ifulnpliilii huilloiiix, in 15 m. of water at Crashboat Landing, Aguadilla (November
20, 1964). Tlic length of this animal, as it is crawling in the picture, was approximately 35
cm. Forward prngres.Mon i> toward the right; visible are the cloacal aperture at the rear end
of the animal to the left and a lateral fringe of papillae bordering the ventrum.
Synaptidae, whose members possess calcareous spicules in the form of anchors and
anchor plates and tentacles with slender digits. The observations reported in this
study were made on animals living in Monterey Bay, California.
Limited studies were carried out on Synaptitlu Jiydrijonnis (Le Sueur, 1823),
a viviparous member of the Synaptidae. This is an abundant species of the West
Indian fauna, usually living a-vsociaied with algae. All specimens were collected
from the red alga, Lanronia /v//>;7/.w/. \\hich grows on a sandy bottom in the shade
of red mangroves (Rhizophora nnintjlc'} on the reef flat at Cayo Majimo, La
I'arguera, I 'uerto Rico.
P.eraii>e different methods were employed in the various experiments per-
formed, the.se are discussed separately under the appropriate, sections to follow.
ACTIVE HOLOTHURIAN MOVEMENTS
109
ASTICHOPUS MULTIFIDUS
Habitat
Astichopiis has been found at five different localities in the coastal waters of
western Puerto Rico (Fig. 2). It is most abundant on the northwestern coast,
and at Crashboat Landing, midway between Pta. Borinquen and Aguadilla, several
specimens have been observed on numerous occasions throughout the year. The
species has been seen at depths of 201-0 m. at different times near Isabela, Camuy
and Arecibo, and probably occurs in favorable localities between these areas. 2 The
Son Juan
KEY
Number of individuals actually
collected
O Presence observed
Presence inferred
FIGURE 2. Map of western district of Puerto Rico showing the localities where Astichopus
has been collected (solid circles) and observed (open circles) from June, 1960, to October,
1964. Its probable occurrence along the north coast is also indicated (dots). The small inset
map of Puerto Rico shows the sector of the island examined.
results of a typical collecting trip to obtain specimens of Astichopiis, conducted at
Crashboat Landing on September 29, 1964, give an approximate indication of its
abundance in this locality. Three individuals were found, two at a depth of
20 m. and one at 10 m. (measured with a wrist depth gauge), by two SCUBA
divers swimming abreast, searching a path 10 m. in width over a distance of
A dense growth of the marine phanerogam, Halophila baiUonis, was present
where Astichopiis was collected at 20 m. ; the other specimen was taken from the
bare sandy bottom. An underwater photograph of a cucumber on a Halophila-
covered bottom is shown in Figure 1. The four individuals of AsticJwpiis re-
ported from La Parguera were found in the months of January, February, August
and October at a depth of from 1 to 3 m., either on a bottom with a dense growth
of turtle grass (Thalassia tcstudinum) , or nearby on the bare sand on the leeward
2 Gary E. Branham and Alfred H. Hummel informed the author of the occurrence of
Astichopiis at all localities from Pta. Borinquen east to Arecibo.
110 PETER W. GLYNN
side between the two inshore coral reefs, Cayo Caracoles and Cayo Majimo. The
present observations on the bathymetric range of Astichopus support Deichmann's
(1963) belief that this species normally lives in deeper water, occurring at shallow
Other echinoderms observed commonly at Crashboat Landing on the sandy
bottom between 30 and 45 m. of depth were the echinoids, Astro pyga magnified
(Diadematidae) and M count vcntricosa (Clypeasteridae). Astropyga is not re-
ported from La Parguera and Mcoina has been found there only infrequently.
Physically and biologically the shore line from Aguadilla to Camuy is decidedly
different from that in the vicinity of La Parguera on the south coast. Kaye (1959)
has described the northwestern coast, from Aguadilla to Arecibo, as largely com-
posed of a limestone cliff, occasionally interrupted by a narrow rocky or sandy
bench, which often forms a firm surface where cementation of dunes has occurred.
Mangrove forests border most of the coastline around La Parguera and shallow
fringing and patch reefs, composed of such prominent coral species as Acropora
palmata, Montastrea annnlaris and Poritcs poritcs var. fnrcata, are numerous
(Almy and Carrion, 1963).
Considerably stronger waves buffet the north coast of Puerto Rico than along
the south shore, except during cyclonic disturbances from the southern quarter
(Glynn, Almodovar and Gonzalez, 1964). The normally heavy surf along the
north coast is a result of the following conditions : (a) this region is exposed di-
rectly to the high seas generated across the Atlantic Ocean, (b) the island shelf
is narrow with few offshore reefs and banks, and (c) the windward shore receives
large swells resulting from storms in the North Atlantic during the winter season
(Kaye, 1959).
Substantial fresh-water discharge is also a prominent feature along the Atlantic
seaboard of Puerto Rico. Because of the southern location of the north-south
drainage divide, seven of Puerto Rico's 17 principal rivers, with an approximate
drainage area of 1398 square miles or 64% of the total considered here, discharge
at more or less regular intervals along the north coast (Arnow and Bogart, 1960).
No permanent river system is present in the vicinity of La Parguera on the south
coast.
Surface sediment samples (upper 5 cm. stratum), collected from the sites
where Astichopus was found in greatest abundance at Crashboat Landing and
Cayo Caracoles, vary considerably in grain size and composition (Fig. 3). The
median diameters and degrees of sorting (as indicated by phi standard deviation ;
Tnman, 1952) for the Aguadilla and La Parguera samples were 0.212 mm., with
1.1 phi-units and 0.392 mm., with 2.2 phi-units, respectively. The terrigenous
fraction of the sample from Crashboat Landing contained mostly quartz and feld-
spar with about 5 r f heavy minerals. Calcareous bioclastic materials, constituting
97.2% of the dry weight of the sample from La Parguera. were nearly three times
as great as at Aguadilla. Ifaliuicihi fragments were the principal constituents
in the south coast sample, with the remainder composed of broken skeletons of
other calcareous algae, the sessile foraminiferan. Hoinotrcnui nthnini, coral frag-
ments, echinoid tests and spines and a varictv of other invertebrate hard parts.
The more poorly sorted sediment sample from La I 'arguera might be explained by
the high per cent composition of plate-like Halnucda fragments and the location
ACTIVE HOLOTHURIAN MOVEMENTS
111
of the area on the Caribbean Sea, in the lee of the heavy swells and surf action
of the Atlantic coast of Puerto Rico. Sediment analyses reported by Guillou
and Glass (1957) confirm the divergent character of the substrata as revealed in
the present study. Calcareous and non-calcareous materials were observed to be
present in equal amounts in the beach sands from Aguadilla to Rio Camuy, while
inshore sediments along the southwestern coast (all of south coast as shown in
Figure 2) were predominantly calcareous.
99 99
2 95
: 84
^
I 50
16
5
- Crasnboat Landing
Terrigenous residue 62.5
Calcium carbonate
Organic matter
368
0.7
b - Cayo Caracoles
trace
97.2
2.8
-1.0 1.0 3.0 5.0
2.0 0.5 0.125 0.031
Phi-units and grain size
mm
FIGURE 3. Plot on probability paper showing cumulative percent distributions of grain
size in sediment samples from Astichopus habitats at Crashboat Landing, Aguadilla (a) and
Cayo Caracoles, La Parguera (b). The per cent composition of the samples, based on dry
weight, is tabulated in terms of terrigenous residue, calcium carbonate and organic matter con-
tent. Grain size distribution was determined by standard sieve analysis, calcium carbonate
and organic matter contents by the difference in weights obtained after ample treatment with
HC1 and H 2 O 2 , respectively. The H 2 C>2 technique employed is outlined by Stevenson and
Emery (1958). Terrigenous residue, as here denned, was that portion of the sample remaining
after the above treatment.
Movements
Clark (1933) observed that Astichopus is a very active form and remarked
(p. Ill) that it ". . . moved about more obviously than any other large holo-
thurian I have ever watched." The various movements performed by Astichopus
were studied in the field during daylight hours and in the laboratory during the
day and at night. Animals maintained in captivity were kept in 200-liter
DUROTEX (asbestos) troughs and 210-liter aquaria supplied with running sea
water. Figure 4 illustrates some of the different movements observed, and the
account of these follows.
A slow crawl is the most frequent means of progression when the animal is
left undisturbed (Fig. 4a). All specimens observed in the field were crawling
over the sandy bottom, ingesting the substratum by means of the circlet of large
tentacles surrounding the mouth. Examination of gut contents showed that there
112
I'KTKR \V. GLYXX
is no apparent discrimination of particle size, and that large fragments of either
living or dead plant material arc generally avoided. Two cucumbers, timed while
crawling under laboratory conditions and not feeding, progressed at a mean rate
of 0.25 and 0.15 in.. / min. ( Table [). Individuals observed in the field while
feeding moved along at a slower rate. As indicated by the lengths measured in
the two individuals included in Table 1 I. a disturbed animal will contract to about
three-quarters of its crawling length. When the body is contracted the dermal
papillae (dorsal tube feet) are frequently withdrawn into the body wall. The
Fna'KK 4. I -"our distinct movements performed by .Istic/inpiis in captivity. The four
photographs in each horizontal series demonstrate (a) crawling, (b) bounding, (c) rolling and
iili an exploratory activity. Arrows in .-erics (a) through (c) indicate the direction of for-
ward progression, vicuing the photographs in sequence from left to right. The inset scale
in the first photograph in series (d) indicates approximately the sixes of the three different
individuals illustrated. The actual lengths of the specimens, measured while crawling, were
(a) 32 cm., (b) and (c) 30 cm., and (d) 46 cm.
crawl is accomplished through the forward progression of a peristaltic wave
originating from the posterior end of the animal. The posterior end is first ele-
vated two to four cm. from the substratum and then the wave moves forward,
forming a two-cm. -high arch between the ventrum and the underlying surface.
Of the many tube feet uniformly distributed oxer the ventrum, the few attached to
the substratum are detached momentarily as the peristaltic wave moves forward.
Three peristaltic waves passed across the bodv of a 40-cm individual in a mean
time of (o seconds. A second cycle is initiated by the time the first has moved over
two-thirds of the body length.
ACTIVE HOLOTHl'RIAN MO\ 'KM KNTS
113
Under certain conditions, to be discussed in the next section, the crawl will
suddenly quicken to a walking or a bounding type of locomotion (Fig. 41)). A
gradation in speed from crawling to bounding is clearly evident, but once one of
the three modes of progression is executed it persists for some few minutes, \\~alk-
ing speeds of three-quarters to one ni./min. are usual, whereas one and one-half
to two m. /inin. are rates typical of the bounding movement (Table I). As in
crawling, both walking and bounding are initiated by a peristaltic wave which
moves forward along the body. However, the cycle is obviously more rapid and
exaggerated at greater velocities. For example, in the bounding movement a wave
passes along the entire length of the body in three to five seconds and there is no
attachment of the tube feet to the bottom. As a wave terminates anteriorly, the
forward end of the body is thrown upwards forcefully and at the same moment a
new cycle begins at the hind end. Fven at the highest speed attained, Astichopus
TABLE I
Rates of progress-ion for the crawling, walking and bounding movements of
Astichopus as observed in captivity
Specimen
Type of movement (m./min.)
Crawling
Walking
Bounding
Light brown individual; crawling length
39 cm. ; contracted length 30 cm.
0.23
0.25
0.62
0.76
1.72
1.89
0.26
0.88
1.98
X 0.25
0.75
1.86
Dark
39
brown individual; crawling length
cm.; contracted length 32 cm.
0.12
0.16
0.74
0.90
1.33
1.43
0.18
1.01
1.71
X 0.15
0.88
1.49
always maintained contact with the bottom. Indeed, it appears that this contact
is necessary for the forward thrust, since animals pushed over on their sides and
still bounding remain essentially stationary. Many of the dorsal papillae contract
into the skin while the animal is walking or bounding. The total distance covered
by one specimen while bounding in an aquarium was about 10 in. Fach time the
animal reached the obstructing wall at the end of the aquarium it was turned around
gently so as not to interfere with its forward progression. Animals walking or
bounding tended to deviate little from a straight-line course. Only limited bound-
ing movements have ever been observed in the field, i.e., of the order of one to one
and one-half m. traversed at a time.
A swimming-like response was observed by Cutress (personal communication)
on one occasion. The animal actually left the bottom and progressed through the
water in an undulatory manner. Further attempts were made to repeat the act,
but they resulted only in the bounding movement already described. In the
present study one individual on two different occasions was stimulated to bound
in the field by subjecting the animal to a sudden change in the temperature of the
114 I'KI EE W. GLYNN
water (see section on environmental effects on movements), but the bounding
movement did not lead to swimming.
Rolling movements also occur frequently, and as shown in Figure 4c the body
Ilexes into a I' during this activiu. A complete roll is carried out in unison along
the whole length of the animal. About one-half of the dorsal papillae are con-
tracted during this movement. ( )ne individual made several complete rolls in a
mean time of five seconds. Rolling may last as long as five minutes, with the
animal moving little from its original position. It became evident that all of the
movements thus far described were less easily evoked in individuals recently stimu-
lated and in some animals activity decreased in frequency and intensity with time
maintained in captivity.
An exploratory or searching activity was observed on only one occasion (Fig.
4d). and this occurred in one of three individuals in the same aquarium imme-
diately after transportation to the laboratory from the field. About one-third of
the anterior portion of the body was elevated, and this swung frequently from side
to side, describing an arc of approximately 40. A full swing to the left is shown
in the second photograph in Figure 4d. The exploratory movements lasted for
about 10 minutes and culminated in the erect posture illustrated in photographs
three and four of Figure 4d. \Yith over one-half of the body in an upright position
the animal bowed forward several times, forming an angle of 45 from the vertical.
The five longitudinal retractor muscles, which must play an important role in
all of the various movements, are very well developed in Astichopus as 1-2-cm.-
broad bands running the length of the body. Comparable muscles in a closely
related, sluggish form. Isoticlwpiis (== Stichopus*) badionotus, are thin and narrow.
The body wall is tough and thick in both species, but soft and pliable in Astichopus
and rigid in Isostichopus. Excessive muscular development has also been reported
in the swimming sipunculid. Sipnnciilns natans (Fisher, 1954), a member of a
typically benthic group. This species has developed strong longitudinal muscle
bands and enormous wing-muscles.
Environmental effects on inurements
In order to learn how the various movements just described may be used to
advantage by Asticliopits, several animals were stimulated in the field and in the
laboratory to produce disturbing circumstances likely to be encountered by the
species in its natural surroundings. Such conditions studied were various bodiK
disturbances, alterations in the temperature of the water, reduction in salinity.
effects of oxygen-deficient water and heha\ ior in numerous divergent light regimes.
In all instances parallel control procedures demonstrated that the movements
evoked were due to the particular conditions under investigation.
Procedure involving mechanical stimulation was as follows. Two individuals
were buried completely beneath the bottom sediments and elevated quickly (in 30
seconds) toward the surface, over an ambient pressure gradient of one atmosphere.
All of the animals responded by contracting initially, then after a minute or
two began to crawl, (ientle handling of specimens normally produce's the same
reaction. All of several individuals, turned oxer on their dorsa and sides, righted
themselves immediately, in 3-5 seconds. 1>\ the rolling movement. A half- or
quarter-roll only was performed to regain normal posture. Since current action
ACTIVE HOLOTHURIAN MOVEMENTS 115
on the bottom is relatively strong at Crashboat Landing, often swaying the animals
from side to side down to a depth of 30 m., this quick, righting response is well
suited to help maintain proper orientation.
Sudden changes in sea water temperature, of the order of 3-4 C.. elicited the
walking, bounding and rolling movements more effectively than any other environ-
mental alterations investigated. To test the effects of temperature, animals were
moved rapidly from one aquarium, at a lower or higher temperature, to another.
In addition, some individuals were maintained in a slightly cooled or heated state
in captivity, and then transferred rapidly to the field. The laboratory sea water
temperatures ranged from 27.5 to 29.3 C. over the duration of the experiments.
Coastal sea water temperatures at this time of the year (October) were in the
range of 27-29 C. Different individuals of Astichopiis were subjected to the
following typical changes in temperature: from 29.1 C. to 32.4 C., and from
27.7 C. to 23.3 C. Essentially the same movements were performed when the
animals were subjected to a temperature which was greater or less than the initial
temperature. Immediate bounding was the most frequent response, lasting for
one to three minutes. A rolling movement was less common, while walking was
observed on relatively few occasions. Once a particular type of movement began
it usually persisted until the animal slowed down to a crawl.
The behavior of Astichopus under different conditions of lighting was investi-
gated with the following light sources : natural daylight, house light (tungsten
filament lamp), red light (infrared lamp), yellow light (sodium lamp), filtered
green light, blue light (mercury lamp) and violet light (ultraviolet lamp). The
light beam was directed so as to enter a 210-liter aquarium on one side from above;
cucumbers were placed lengthwise along the edge of the lighted portion and the
shadow of the dark side of the aquarium, which was covered with black cloth.
Observations were made in a darkroom where the light intensities employed were
equal to or less than 10 foot-candles. Light intensities up to 75 foot-candles were
measured with a Western photoelectric cell (Model 703, sight meter) ; an estima-
tion of greater illumination was obtained by the interposition of green filters over
the photocell and by calibrating the Weston meter against a General Electric Mascot
exposure meter (Type PR-35).
Individuals showed a marked attraction to natural and artificial light of low
intensity (5 foot-candles), by immediately crawling toward the source. No con-
sistent phototactic attraction or repulsion could be discerned at higher light intensi-
ties of 10, 20, 30, 50 and even 11.000 foot-candles (zenith sun at noontime in
November). Usually, however, activity did increase at higher illuminations. In
contrast to the usual photo-negative response of holothurians (Crozier, 1915)
Astichopns crawled with equal frequency toward and away from the illuminated
end of the aquarium. The phototactic behavior of Astichopus seemingly parallels
that of Isostichopus, a form not apparently irritated by a strong source of illumina-
tion.
Monochromatic light was adjusted so that a maximum intensity of 10 foot-
candles entered through one side of the aquarium. Astichopus demonstrated a
strong, positive attraction to red, green, blue and violet light; individuals moved
toward the light immediately by crawling and lingered in the region of greatest
illumination. Only a modest attraction to yellow light was observed.
116 PETER W. GLYNN
.Istichopns did not demonstrate any clear tendencies in geotactic or thigmo-
tactic behavior. Animals climbed readily up and down the vertical sides of con-
tainers and surfaces inclined at various angles to the horizontal. ( )ccasionally
individuals in the field were found alongside submerged pipes and pilings. Move-
ments of confined laboratory animals indicate, however, that the association with
solid objects may occur simply by chance wandering.
Effects resulting from a reduction in salinity were observed in the laboratory
in individuals transferred from the sea water in which they were maintained to
tanks containing sea water diluted with tap water. The normal, mean, surface
salinity on the inshore reefs of the south coast for November, when these particular
studies were made, was around 34. SO'/, (unpublished data). Experimental dilu-
tions were 31.00',, and 17.25'iV. Animals suddenly subjected to these conditions
usually contracted, but occasionally executed a bounding motion. An equal in-
tensity of reaction, in terms of speed and duration, was noted in both dilutions.
Individuals of .-Isticlio^ns were also transferred to oxygen-deficient sea water-
obtained directly over anaerobic mud on the floor of a mangrove canal. < )f tin-
rapid movements a bounding response was elicited most frequently under these
conditions; limited rolling was also observed.
The possibility that the association of Astichopits with members of its own
species or with other organisms may elicit active movements was also investigated.
Individuals together in the same container behaved independently, i.e., they crawled
about as if alone and tended to avoid contact with other cucumbers. Animals in-
troduced into an aerated aquarium in which Astichopiis was previously living-
showed no signs of excitation. The water in this case was recirculated through
a filter instead of being replaced by fresh, running water. Simulated biting, by
firm pinching of different regions of the body with the bare hand, was observed
both in the field and in the laboratory. This evoked a typical contraction of the
body with subsequent crawling after 1-2 minutes. Introduction of a fresh slime
preparation from the skin of Lactoplirys bicandalis, a trunk-fish which regularly
preys on the small holothurian, Microthele (-- Holotlntria) parrnla. in the imme-
diate vicinity of Asticliopits also failed to produce any active movements.
Two observations indicated that AsticJiopns might possibly possess a toxic
substance that adversely .affects other organisms nearby. Petrochirus diogenes, a
large scavenging and possibly predatory hermit crab (Randall, 1964) found in
association with Asticliopus, tended to avoid the cucumber in captivity. In addi-
tion, several fishes in the same aquarium with .Isticlio/^ns died after one cucumber
eviscerated.
Toxicity
Yamanouchi (1955) has clearly demonstrated that numerous species of holo-
thurians are toxic; of 27 species investigated, 24 contained a venomous substance.
Xigrelli and (akowska ( 1 ( >60) reported that poisonous species are known in four
of the five orders comprising the class; members of the deep-sea order Elasipodida
have not been examined in this connection. The total number of species of cucum-
bers known to be toxic to fishes is 30 24 of the.se live in the- Pacific Ocean, three
in the Mediterranean and four in the West Indies (I'ahamas). One of the latter
ACTIVE HOLOTHURIAN MOVEMENTS 1 1 7
species occurs in the Mediterranean and in the West Indies. The toxic principle
in the common Bahamian species. .Ictinopyga agassizi, has been identified as a
saponin, a chemical structure previously unknown in the animal kingdom (Nigrelli
ctal, 1955 ). 3
Investigations were made of the possible adverse effects on other marine animals
of (a) the water in which Astichopns had recently performed active movements,
(b) its coelomic fluids, and (c) alcohol extracts of the body wall. Freshly killed
cucumbers were used in all instances. The potency of Astichopns was assayed by-
observing the effects produced in seven species representative of six different animal
phyla: Coelenterata, Madreporaria Poritcs poritcs var. jurcata Lamarck, 1816;
Annelida, Polychaeta Hcsionc proctocliona Schmarda, 1861 ; Mollusca, Pelecypoda
Lima scabra Born, 1778; Arthropoda, Crustacea Mitlira.v ( Mitliracnlits} scalp-
tiis (Lamarck, 1818) ; Echinodermata, Ophiuroidea Ophiothri.v ongulata Say,
1825; Chordata, Tunicata Ectcinascidia turbinata Herdman, 1880; Chordata.
Pisces Jcnkinsia laniprotacnia (Gosse, 1851). All of the invertebrate species
were held in wide-mouth bowls with one liter of aerated sea water at a temperature
of 28-29 C. ; Jcnkinsia was held in a circular bottle of 10 liters capacity. All
invertebrates except Ectcinascidia were collected on the same day of an experi-
ment from the south shore of Magueyes Island, in association with the fringing
Poritcs poritcs var. furcata reef. Ectcinascidia was collected from mangrove roots
bordering the canal which separates Magueyes Island from the mainland ; Jcnkinsia
was netted near the shoreline of the same canal. Parallel control material, with
at least the same number of individuals observed as in experimental, always accom-
panied each experiment.
Two 10-ml. samples of sea water, taken from separate 5-liter containers in
which one Astichopus had rolled and another bounded, did not produce any visible
effects on the test animals over a 24-hour period.
An unsuccessful attempt was made to stimulate evisceration in three different
individuals by firmly squeezing and pinching various areas of the body. Further,
evisceration did not occur under the diverse experimental conditions to which
Astichopus was subjected. Only two individuals eviscerated over a two-month
period and the cause was not readily apparent. Much of the gut and the respira-
tory trees were ejected ; Cuvieran organs are unknown in all Stichopodidae. For
these reasons, it does not appear likely that evisceration is a normal defensive
response. The body fluids tested for toxicity, then, were obtained by dissection
from the coelomic cavity. Undiluted coelomic fluid, equal to a final concentration
of 1000 ppm. (parts per million), was added to the water in which the test species
were confined, and their reactions observed continuously for the first two hours
after introduction and then at 4 hours and 8 hours. At the termination of the
experiment animals were transferred to running sea water for a duration of 12
hours in order to observe recovery. The various responses noted are summarized
in Table II.
Polyps of the scleractinian coral Poritcs contracted slightly in the first one-half
hour and remained in this state for 8 hours. In 4-8 hours a mild lethargic re-
sponse was observed in Hcsionc, Mitlira.v and Ophiothri.r; they all became less
3 Studies on the chemical nature of the toxic agent are presently being carried out by the
author in collaboration with Horace Graham, Department of Biology, University of Puerto
Rico, Mayagiiez.
118
PETER W. GLYNN
irritable to mild mechanical stimulation. Lima re-acted immediately by violently
closing its valves; after about one hour they began to gape. By two hours the
water became noticeably reddened and contained numerous small fragments of
mantle tissues voided by the animals. Iictcinasciciia responded by slowly contract-
ing until at 8 hours all individuals were dead ; cessation of heart beat was used as
a criterion of death. Jenkinsni, the small clupeid, perished quickly; two fish were
TABLE II
( >l>scn'<itions af the effects on some marine animals of the body fluids of
Astichopus at a concentration of 1000 parts per million
Organism
X umber
observed
Reactions at indicated time intervals
Recovery
(12 hrs.)**
Jhr.
1 hr.
2 hrs.
4 hrs.
8 hrs.
Coelenterata
Parties parties
var. furcata
3 terminal
branches,
over 100
polyps in
each
polyps
slightly
contracted
same
same
same
same
yes
Annelida
Hesione proc-
tochona
3
normal*
normal
normal
loss of
quick
wriggling
response
same
yes
Mollusca
Lima scabra
5
immediate
and com-
plete closure
of vab <
valves open
in 2 indi-
viduals
all open;
small bits of
mantle
tissue
ejected
same
same
yes
Arthropoda
Mithrax ( Mithra-
citlus) sculpt us
4
normal
normal
normal
loss of
quick de-
fensive
reaction
of chelae
same
yes
Echinodermata
Ophiothrix
angulata
5
normal
normal
normal
normal
sluggish
no
Chordata-Tunicata
Rcteinascidia
turbinata
1 colony of
20 in-
dividuals
normal
siphons
slightly
contracted
same
siphons and
body wall
contracted
phons and
body wall
greatly con-
tracted ; no
heart beat
Chordata-Vertebrata
Jenkinsia
lamprotaenia
5
normal
* A normal reaction indicates that no difference could be discerned between the test animals and controls. Same
applies to Tables III and IV.
** Twelve hours in running sea water were allowed for recovery after the termination of the experiment. Same
applies in Tables III and IV.
dead at the end of the first hour and all five had succumbed in two hours. The five
control individuals of Jenkinsia lived beyond the <S hours of the experiment. Re-
covery occurred in four of the five surviving species; Ophiothrix died.
Yamanouchi (1955) and Xigrelli and Jakowska ('1 ( '(>0) have extracted with
hot ethanol an active, toxic principle from the body wall of various holothurians.
Alcohol extracts obtained from Astichopus were prepared as follows. A one-inch
square of the body wall was macerated in a mortar with 30-40 mesh quart/ sand.
The mash and juices were then treated with 50 ml. of ( >5'/r. hot ethanol at 50-60 C.
for 10 minutes. The extracts at concentrations of 1000 and 5000 ppm. were tested
ACTIVE HOLOTHURIAN MOVEMENTS
119
after cooling to room temperature. The results are presented in Tables III and IV.
The reactions of the test animals to alcohol extracts were very similar to those
resulting from exposure to body fluids. Usually, however, a more severe reaction
was evoked by the extract when equal to or at a greater concentration than the
body fluids. The slightly contracted polyps of Poritcs after one hour were com-
pletely withdrawn in two hours. Lethargy again occurred in Hesione, Mithrax
and Ophiothrix. Additional effects observed after 8 hours were inflation of the
TABLE III
Observations of the effects </ some marine animals of an alcohol extract of the
body wall of Astichopus at a concentration of 1000 parts per million
Organism
Number
observed
Reactions at indicated time intervals
Recovery
(12 hrs.)
Jhr.
1 hr.
2 hrs.
4 hrs.
8 hrs.
Coelenterata
3 terminal
normal
polyps
polyps
same
same
no
Poriles porites
branches.
slightly
fully
var. furcata
over 100
contracted
contracted
polyps in
each
Annelida
5
normal
normal
normal
loss of
body in-
yes
Hesione proc-
quick
flated;
tochona
wriggling
proboscis
response
everted
Mollusca
5
active swim-
valves par-
small bits of
moribund
Lima scabra
ming fol-
tially open;
mantle
lowed by
tentacles
tissue
complete
constricted
ejected
closure of
valves
Arthropoda
5
normal
normal
normal
loss of
same
yes
Mithrax (Mithra-
quick de-
culns) sculptus
fensive re-
action of
chelae
Echinodermata
Ophiothrix angulata
5
normal
normal
sluggish
same
autotomy
of arms
no
Chordata-Tunicata
Ecteinascidia
1 colony of
20 indi-
normal
siphons and
body wall
same
same
siphons and
body wall
no
turbinala
viduals
slightly
greatly
contracted
contracted
Chordata-Vertebrata
5
erratic
_
_
Jenkinsia
swimming
lamprolaenia
followed by
death in 10
minutes
body and eversion of the proboscis in Hesione and extensive autotomy of the arms
in Ophiothrix. Violent swimming movements were executed by Lima in the first
few minutes, followed by closure of the valves. Individuals began to open after
1-2 hours ; the pallial tentacles were noticeably shortened and constricted ; red-
dened water, apparently due to the leakage of blood through ruptured tissues,
appeared after two hours. All specimens of Lima succumbed during the experi-
ment. Ecteinascidia responded by severe muscular contraction and cessation of
heart beat at a concentration of 5000 ppm. Rapid, erratic swimming commenced
in Jenkinsia immediately, resulting in the death of all specimens within 10 minutes.
The gills were reddened in fish subjected to a concentration of 5000 ppm., indi-
cating hemorrhage of the capillaries. A similar cause of death was observed in
120
ITTKK W. GLYNN
the killitish, Cyprinodon haconi, after exposure to an aqueous preparation of the
toxic agent of .Ictinopytjd ai/assici ( Xigrelli, 1952). Five species survived and
two recovered from exposure to the extract at 1000 ppm., whereas of the four
survivng species at 5000 ppm. only the niajid crah, Mit/ira.v, recovered.
TABLE IV
of the effects on some marine animals of an alcohol extract of the body
ictill nf A ^tichopus at a concentration of 5000 parts per million
Organism
Number
observed
Reactions at indicated time intervals
Recovery
(12 hrs.)
Jhr.
1 hr.
2 hrs.
4 hrs.
8 hrs.
Coelenterata
3 terminal
normal
polyps
polyps fully
same
same
no
Forties porites
branches.
slightly
contracted
var. furcata
over 100
contracted
polyps in
each
Annelida
5
normal
normal
less active
sluggish;
body in-
no
Hesione proc-
loss of
flated;
tochona
quick
proboscis
wriggling
everted
response
Mollusca
5
active swim-
valves
Lima scnbra
ming fol-
tightly
3 moribund;
1 moribund
lowed by
closed
valves par-
complete
tially open ;
closure of
small bits of
valves
mantle
tissue
ejected
Arthropoda
3
normal
normal
normal
loss of
same
yes
\litlirnx ( Mithra-
quick
culus) sculptus
defensive
reaction of
chelae
Echinodermata
5
normal
normal
sluggish
same
autotomy
no
Ophiothrix
of arms
angulata
Chorda ta-Tunicata
1 colony of
normal
siphons and
___
Ecteinascidia
20 indi-
body wall
siphons and
turbinata
viduals
slightly
body wall
contracted
greatly con-
tracted; no
heart beat
Chordata-Vertebrata
5
erratic
_
_
_
Jenkinsia
swimming
lamprolaenia
followed bv
death in 11)
miniili-- ,
Kills
reddened
LKI'TOSVNAI'TA Al.BICANS
< )n three different occasions over the period January-May, 1957, four adult in-
dividuals of Leptosynapta ull'icdus were ohserved swimming at night light stations
in Monterey Kay, California. During that time of year, night light stations were
occupied at approximately weekly intervals. All observations were made on dark
nights hetween ( > :()() and 1 1 :()() I'M, from a float secured to the Monterey Municipal
Tier. The sea hottoni is sandy helow the float and ahout 7 in. dee]) (measured
ACTIVE HOLOTHURIAN MOVEMENTS
121
from mean sea level ). 4 The direction of swimming was along the outer border of
visibility illuminated by a 200-watt lamp suspended in the water about three m.
away from the observer.
The swimming animals described a sinusoidal path as they moved through the
water near the surface (Fig. 5). It was not possible to determine whether the
progressive waves of activity occurred in the lateral or dorso-ventral plane. While
swimming the cucumbers were extended in length to about 20 cm., but when
captured quickly contracted to about 5 cm. It is estimated that a complete wave
passed from the head to the tail end in about two seconds, and that the animals
5 CM
FIGURE 5. Diagrams of the undulatory swimming movements performed by Leptosynapta in
tin- field (a and b) and the more frequent appearance of the animal when crawling (c).
moved through the water at a rate of one meter per minute. Individuals appeared
to move in the direction of the tentacular crown, although this requires verification.
Participation of the tentacles in swimming appeared insignificant. Hoshiai (1963)
observed that Labidopla.v turns its anal end in the direction of movement. Like
the swimming young of Leptosynapta (Costello, 1946) and Labidoplax, captured
adult Leptosynapta did not void an appreciable amount of fecal material. Three
specimens dissected open showed no signs of recent gonadal activity.
All netted specimens were transported to the laboratory and maintained in an
aquarium with running sea water. To induce swimming the same animals were
treated in the following ways: (a) maintained in natural and total darkness, (b)
subjected to sudden changes in light intensity (the most severe of these involved
transfer from a dark room to direct sunlight), (c) dropped through a four-foot
column of water, (cl) subjected to a sudden increase or decrease of water tempera-
4 This area has not been re-examined since the construction of a nearby breakwater and
small craft shelter.
122 PETER \V. GLYNN
ture (14 4 C.I. (e) subjected to electric shocks (three graded scries of voltages
at 1, 10 and 100. each deli\ere<l al !re<|uencies of 1, 10 and 100 per second), (f)
sul)jectecl to a sudden increase in concentration of acid (HC1) or base (NaOH) ;
two to three drops of IS N HC1 and a saturated solution of NaOH (ca. 30 N)
were introduced separately into one end of a small pan containing the cucumber.
An attempt \vas always made to keep deleterious stimuli at a sublethal level. None
of the above treatments elicited a swimming response. In most cases the cu-
cumbers tended only to avoid the stimuli by contracting the body and tentacles.
Since swimming movements have been reported for three species of apoclid
holothurians, Syiniptnla hydriforwis, a readily available species belonging to the
same group, was also investigated. Stimuli identical to those enumerated above
were administered to several individuals of Syuaf>tula. In addition, a fresh slime
preparation from the skin of the trunk-fish, Lactophrys bicaudalis. was introduced
into an aquarium containing several individuals of Synaptula. The sea water tem-
perature during the experiment was 28 4 C. As in Lef>tosyna[>ta, none of these
treatments prompted a swimming or otherwise active response. The reactions
were similar to those observed by Olmsted ( 1 ( '17). involving muscular contraction
of various parts of the body.
DISCUSSION
It is of interest to contrast the habitat of Asticliopits in Puerto Rico with that
portion of the Campeche Bank in the Gulf of Mexico where the species also occurs
in abundance. Numerous specimens are commonly encountered in the shrimp
grounds on the Campeche Bank, from a few fathoms down to a depth of 20 m.
The location of the shrimp grounds in this region (Hedgpeth, 1954, p. 206). when
compared with Lynch's (1954. p. 79) map of the sedimentary provinces, shows
that the bottom deposits are essentiallv mudd\ . The usuallv muddv and estuarine
/i* -
conditions where shrimps are found along the Gulf coastal states, including a high
organic matter content, contrast notably with the environment of the north coast
of Puerto Rico. However, there is evidence that the faunal composition of t In-
more southern shrimping grounds is decidedly different from that in the northern
Gulf (Hedgpeth. 1 ( >5.}. 1954), perhaps reflecting significantly different physical
and chemical properties of the environment as well. Kornicker ct al. (1959), who
compiled a list of the biota of Alacran Reef, located near the center of the Campeche
Bank and away from muddy deposits, did not report the presence of Astichopus
or the seagrass, Halophila.
The relationship between grain si/.e and the distribution of benthic feeding
types suggests a further complication in an attempt to delineate the set of environ-
mental factors favorable to the species. Sanders' ( T>5S ) findings, that clay is a
good sediment correlate in the distribution of deposit-feeding organisms, would
seem to apply where .Isticliopns occurs in very line sediments on the Campeche
Bank. However, Me \ulty ct al. (1962), in agreement with the present findings,
observed that deposit feeders were most abundant in sediments with a median grain
size of about 0.25 mm. < >n the other band, individuals of Asticliopus with a dry
body weight (excluding ingested materials i of the order of 100 gm. do not lie on
the curve relating body si/.e to grain si/e proposed by McXulty and co-workers for
deposit feeders. According to their findings, which show a linear relationship be-
ACTIVE HOLOTHURIAN MOVEMENTS 123
tween grain size and the cube root of dry tissue weight, one would expect AsticJwpus
to occur in sediments with a median grain diameter in excess of 0.8 mm. The
delicate and highly dendritic structure of the tentacles and the way these are em-
ployed in ingesting fine sediments indicate that feeding may be more efficiently exe-
cuted on fine-grained substrata.
Deichmann (personal communication) has observed that many species of cu-
cumbers go shorewards during the breeding time. However, the four individuals
of Astichopus found in shallow water in La Parguera did not have the gonads in
an active condition. Possible breeding in the late autumn or early winter is sug-
gested by the occurrence of a 5-mm. AsticJwpus in shallow water in the Bahamas
in May (found by C. Fernandez Mosher). La Parguera specimens were collected
in the winter, summer and autumn seasons. The present scanty records indicate
that the occurrence of Astichopus at shallow depths is not associated with breeding.
The walking, bounding, rolling and erect exploratory movements of Astichopus
represent newly-described activities for the benthic Holothuroidea. Even the
relatively slow crawl of this highly active species is rapid compared with other
forms. The mode of crawling in Parastichopus pari'hncnsis (Parker, 1921) re-
sembles very closely that in Astichopus. but individuals of nearly equal size pro-
gressed at a rate of only 1 m./15 min., or 0.07 m./min., equivalent to one-fourth
to one-half the speed in Astichopus. Peristaltic waves pass along the bodies of the
two species at the same rate, viz. at mean times of 63 seconds in P. parr'nncnsis and
65 seconds in AsticJwpus. In Parastichopus one peristaltic wave at a time passes
over the body ; in Astichopus a second cycle begins before the first has ended.
The swimming movements of the species Bathyplotcs natans were described by
M. Sars (Hansen and Madsen, 1956) as similar to those of swimming leeches.
The snake-like bends of the body occurred in the dorso-ventral plane, not side-wise.
Assuming that the progressive peristaltic waves were initiated from behind in
Bathyplotcs (in leeches the waves pass back along the body from the head) it is
possible that the swimming observed in Astichopus by Cutress is very similar to
that reported by Sars.
A speed of nearly 2 m./min. attained by Astichopus when bounding, approaches
the greatest velocities observed among echinoderms, viz. comatulicl crinoids, 5
m./min.; Ccntrostcphanus longispinus (echinoid), 2.1 m./min.; Crossaster papposus
(asteroid), 2 m./min.; ophiuroids, 1.8 m./min. (Hyman, 1955). Prosobranch
gastropods, which, like sea cucumbers, progress by means of peristaltic waves, are
considerably slower; one rapid crawler, Thais nistica, attained a maximum velocity
of 0.3 m./min. (Coomans, 1961).
The fast movements performed by Astichopus may actually facilitate a more
out earlier, a rolling movement is used by the cucumber for stabilization in strong
currents. The method by which a bounding movement could help Astichopus
avoid conditions of high temperature stress is suggested by the following possible
circumstances. Reactions to light and gravity indicate that Astichopus is capable
of moving readily into shallower or deeper water. Also, this species is very
sensitive to a sudden change in the sea water temperature; such a change will
immediately evoke a bounding response. Protected, shallow bodies of water heat
up considerably during mid-day low water phases of the tide in the summer. For
124 i>|. r|.;u' ,\ . CI.VNN
example, on one occasion in La I'arguera a temperature difference of 8 C. was
observed between shoal water on the Ice side of a reef (36 C.) and the surf zone
to windward (28 C. ) . A cucumber wandering into such heated shallows could
possibly escape the high temperature if the bounding movements were executed
and properly directed. Abrupt changes in temperature are probably not so fre-
quently experienced where .-Isticliopns occurs at greater depths. Bathythermo-
graph curves, obtained from stations located slightly less than one mile west of
I'ta. Borinquen, show that a distinct thermocline occurs as deep as 90-120 in., with
a temperature gradient of .V C'. over about 7 m. (Gilbert Hane, personal com-
munication ) .
Bounding sometimes resulted under experimental conditions when animals were
suddenly subjected to reduced salinities and oxygen-deficient water. Although
ample data are not available on the patterns of salinity and oxygen distributions
around the river mouths on the north coast, aerial views show turbid river dis-
charge extending seaward 2-3 miles and as streaks up to 5 miles along the coast.
The effects of such conditions on populations of Astichopus will be the subject of a
future investigation.
Aside from an exploratory type of behavior, observed on only one occasion
in captivity (in the presence of two other animals), active movements are not
elicited in .Ist/clwpus through association with members of its own species. Ex-
posure to the juices of a possible predator ( Lactophrys bicaudalis) also failed to
arouse the cucumber. Sund (1^58) likewise could not demonstrate that certain
supposed predatory starfishes were responsible for quick swimming movements
performed by the actinian. Stoniplihi coccinca.
Water in which .-Isticliopus had performed movements did not have a toxic
effect on other animals, thus showing that increased activity does not cause the re-
lease of a toxic substance. The coelomic fluid caused death in a species of brittle
star, tunicate and fish at a concentration of 1000 ppm. However, the likelihood
that body fluids are released naturally does not seem great, since Astichopus is not
inclined to eviscerate even under extreme irritation. Alcohol extracts of the body
wall proved to be more toxic than the coelomic fluids; five of the seven species
tested perished at a concentration of 1000 ppm. Yamanouchi ( 1955) concluded that
the poisons contained in holotlmrians apparently have little ecological significance.
Though the toxic principle is confined largely to the tissues of the cucumber, a pos-
sible role of influencing the activities of other animals through diffusion of trace
amounts into the surrounding water, for example in averting potential predators,
cannot be dismissed.
C'ostello's (1'Mu) description of nocturnal swimming bv the young of Lcpto-
\yiHipta has dispelled the common notion that this species passes its entire post-
planktonic life completely buried in soft bottoms (Hyman, 1^55, p. 209). Moreover,
the undulatory swimming movements performed by adult I.cptosvinipta show that
Costello's suggestion is not true, namely that (1'Mn, p. ( >5 ) ". . . Lcptosvinipta
>wims only during a limited period of Us voting adulthood." The scissor-like bodv
flexures in the swimming young are entirely different from the sinusoidal undula-
tions which move across the entire length of the body in adults. In addition, the
movements of the young were described by Costello as more or less aimless, with
ACTIVE HOLOTHURIAN MOVEMENTS 125
a velocity of 5-6 cm./min.. whereas in adults swimming was directed and occurred
at a velocity of about 1 in./min.
Specimens of Labidoplax dnbia, like aduli Leptosynapta species, also swim in
an undulatory manner (Hoshiai, 1963). Curiously, though, this species holds
its anal end highest and toward the direction in which it is moving. Labidopla.r
swims from early June to late July during any lunar phase, but only after darkness;
swimming begins one hour after sunset and ends one hour before sunrise. By
inducing several individuals to swim in the dark during the day, Hoshiai clearly
substantiated Costello's idea that swimming in synaptids is a dark-conditioned
phenomenon. Darkness and a variety of other experimental procedures did not
elicit swimming in adult Leptosynapta. It does not seem likely that the swimming
behavior is related to spawning, since the gonads showed no signs of being in a ripe
condition or recently spent. Furthermore, Runnstrom observed that Lcptos\naphi
albicans erects itself only part way out of the burrow when spawning (Hyman,
1955, p. 176). In the light of present knowledge no definite statement can be made
about the stimulus that evokes swimming in synaptids or the possible benefit received.
SUMMARY
1. Aspects of the biology of the aspidochirotid, Astichopus nnt/tifidus and the
apodid, Lcptosyuapta albicans, studied in Puerto Rico and California, respectively,
were investigated in relation to the active movements performed by these species.
2. Astichopus is present in greatest abundance between 10 and 40 m. of depth
on the northwestern coast of Puerto Rico. It often occurs in or near beds of the
marine phanerogam, Halophila baillonis. Sandy beaches, cemented dunes, and
beach rock, exposed to the heavy seas of the Atlantic Ocean, make up the shoreline
of this region. Numerous large rivers loaded with terrigenous materials dis-
charge on the north shore. The sediment on which Astichopus lives is compara-
tively fine-grained (median diameter 0.212 mm.) and well sorted (o-^l.l);
the terrigenous component is high (62.5%), calcareous bioclastic materials occur
in substantial amounts (36.8%), and the organic matter content is low (0.7%).
A smaller number of AsticJiopus has been collected from shallow water ( 1-3 m.)
in the winter, summer and autumn at La Parguera on the south coast.
3. In addition to a comparatively fast crawl, forward progression in Astichopus
is executed by rapid walking and bounding movements, which in the latter case may
approach a rate of 2 m./min. Rolling and exploratory movements are also per-
formed by Astichopus.
4. Mechanical stimulation usually causes Astichopus to contract for 1-2 minutes.
Walking, bounding and rolling movements are elicited by sudden changes in the
temperature of the water, of the order of 3-4 C. A positive phototactic response
occurs at low light intensities (5 foot-candles); photota.xis increases at higher
light intensities, but no definite negative response is apparent. A strong positive
attraction to red, green, blue and violet light is evident at a low intensity of 10
foot-candles. No clear tendencies were noted in geotactic or thigmotactic behavior.
Bounding movements sometimes occurred when cucumbers were suddenly subjected
to diluted sea water and oxygen-deficient water. Active movements were not
evoked through the association of Astichopus with members of its own species or
in the presence of other animals.
126 PETHR W. GI.YXX
5. Coelomic fluids and alcohol extracts of the body wall of Asticliofns are toxic
to a variety of marine animals at concentrations of 1000-5000 ppm. It does not
seem likely that a poison is released by the animal naturally, since the water in
\vhich active movements are performed is non-toxic and evisceration occurs only
rarely.
6. Sinusoidal swimming movements wen- observed in adult Leptosynapta on
three different occasions near the surface at night. Specimens subjected to a
variety of experimental conditions in captivity failed to elicit the swimming re-
sponse. Svnaptula Jivdrijonnis. a related West Indian species, did not swim either
when subjected to diverse stimuli as with Leptosynapta or when exposed to the
juices of a presumed predatory trunk-fish.
LITERATURE CITED
AI.MY, C. C., JR., AND C. C ARMH'X-ToRRES, 1963. Shallow-water stony corals of Puerto Rico.
Caribbean J. Sci., 3: 133-162.
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CLARK, H. L., 1907. The apodous holothurians. A monograph of the Synaptidae and
Molpadiidae. Smithsonian Contrib. Knowlcdfic, 35: 1-231.
CLARK, H. L., 1933. A handbook of the littoral echinoderms of Porto Rico and the other West
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COOMANS, 11. H., 1961. Experiments on the velocity of marine gastropods. Ann. Rept. Am.
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COSTELLO, D. P., 1946. The swimming of Lcptosynapta. Biol. Bull., 90: 93-96.
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marine life in La I'arguera, I'uerto Rico. Ctiril>hcan J. Sci.. 4: 335-345.
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ACTIVE HOLOTHURIAN MOVEMENTS 127
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THE BIOI.i HiY <>! \SUMIA \HiRA (SAVIGNY). [II. THE ANNUAL
PATTERN OF COLONIZATION 1
[VAN GOODBODY
lh-f>(irtmcnt of '/.oniony, I'nhrrsity of the U'cst Indies, .fniiniicti
In the first paper in this series (Goodhody, 1962) an account was given of the
development and survival of a single ])opulation of ascidians at Tort Royal.
Jamaica. In October. 1 ( '5 () . a second experiment was initiated with the object of
comparing populations which settled and commenced life at different seasons of
the year. The present paper deals solely with aspects of colonization and supports
the view previouslv expressed that Ascidia n'ujra is a primary colonizer in the
sessile community and only succeeds with difficulty in developing in the later stages
of community succession. A subsequent paper will deal with survival in the same
population.
METHODS
The methods used for obtaining populations were exactly the same as described
previously (Goodbody, 1 ( ^>2). Panels of Tufnol with an available settlement area
of 216 sq. in. on each side were suspended from rafts at the same locality and in
the same manner as before; natural sessile communities, which included popula-
tions of Ascidia ni</ni, were allowed to develop on the panels, which were inspected
at monthly intervals. Altogether six separate populations were set up in this
way and were designated A. B, C, D, E and F. Four panels were used for each
population, two sited at four feet and two at eight feet below the sea surface. The
populations were set up so that thev commenced life at intervals of two months over
a period of a year; this was accomplished bv immersing the sets of panels at suc-
cessive intervals as follows:
Population l>aic<>l panel immersion
A 1st October 1959
15 1st DrrcmlxT 1'J.S'J
C 1st I'Ybruury I960
I) 1st April 1060
K M June 1960
!' Is1 August 1960
After immersion even panel was examined and photographed at monthly intervals
and a permanent record thus obtained of the fate of every individual ascidian.
l\econU of settlement continued until March, 1 ( >(>2, and of survival until October,
1 (| '2. Copulation C suffered damage and handling lo.ss in the winter of 1960/61
and observations on it were abandoned alter January, 19(>1.
' Sii]>i>i irtcd in part l>y a tyrant from tin- Xul'lirld Foumlatii ,n.
128
BIOLOGY OF ASCI DI A \K,k \
129
THE PATTKRN OF COLONIZATION
Table I shows the number of new colonizers recorded in each population in
each month throughout its history. It should be noted, however, that no counts
were made in the first month for populations A, B and F, so that in each of these the
figure given for the second month is the grand total of new colonizers in the first
two months after immersion. Furthermore it was not possible to make any ob-
servations in November, 1960, so that the figures for December are totals for the
period October to December.
These data reveal several points concerning the ecology of +1. nic/ra. First,
it will be seen that with the exception of population E (immersion date June, 1960)
all the populations had dense colonization during the first two months after im-
mersion but very few colonizers in subsequent months. In the earlier paper the
same phenomenon was observed but it had to be assumed that the fall-off in the
number of new colonizers was due to some form of competition and was not due
TABLE I
The number of new individuals appearing in each month within different populations of
Ascidia nigra. Months given in parentheses indicate the month in which the panels
were first immersed
Month
Population
A
(Oct., 1959)
B
(Dec., 1959)
c
(Feb., 1960)
D
(April, 1960)
p 1
(June, 1960)
P
(Aug., 1960)
Dec., 1959
147
Jan., 1960
10
Feb.
2
463
Mar.
4
199
April
1
4
48
May
1
2
7
415
June
1
3
1
101
July
1
1
5
74
Aug.
6
2
12
Sept.
1
13
2
Oct.
6
33
187
X ov.
Dec.
8
2
37
35
80
31
Jan., 1961
2
11
6
5
34
4
Feb.
2
2
2
16
6
Mar.
1
1
4
1
2
April
2
1
6
8
May
30
2
5
June
8
3
1
July
3
Aug.
2
1
4
3
Sept.
1
3
7
2
Oct.
4
7
5
6
Nov.
4
7
9
9
9
Dec.
7
5
10
3
8
Jan., 1962
1
8
6
12
1
Feb.
2
1
3
1
2
Mar.
3
IV \\ . .. 10DBODY
to the absence of larvae for settlement. The present data prove this assumption
'to have been correct. The fact that larvae were continually available for new
colonization throughout the year is shown by the high density of colonizers occurring
on the newly immersed panels of successive populations and yet, while these new
settlements were occurring, the older populations were- receiving a negligible number
of new colonizers.
If we accept this view, that competition is responsible for the decline in new
colonizers after the second month, we must enquire what form the competition takes
and whether it functions by preventing new settlement or preventing growth of
animals after metamorphosis. The development and succession in these com-
munities have been briefly outlined elsewhere (Goodbody. 1963c) and will be dis-
cussed in detail in a later paper. The important aspects of this development are
that an earl\ Balanus/Enterovnorpha community, in which A. nu/ra colonizes, is
rapidly overgrown by the colonial ascidian, Iiidcninum concliyliatniii (Sluiter),
so that this ascidian and A. nit/ra become temporary dominants in the second serai
stage. After a period of 7 to 12 months the Dideinintin fragments and retreats, and
sponges, lamellibranchs and stolidobranch ascidians become climax dominants. The
rapid decline in colonizers after the second month is almost certainly due to the
rapid spread of l>. conchyliatum and, to a lesser extent, other colonial ascidians.
These colonial ascidians overgrow and smother the smallest-sized young Ascidia
iiit/ra ( Goodbody j l ( '(>3a) and also, by covering all available surface of the panel,
effectively prevent any further settlement. Competition at this stage is therefore
for space and not for food, those individuals of A. nigra which have successfully
gained a foothold continuing to grow rapidly in association with the D. conchy-
liatum.
In the later stages of serai succession the problem becomes more complex and
difficult to unravel. With certain exceptions noted below fresh colonization in the
community continues at a low level even though the sheets of D. concJiyliatuin
fragment and disappear. A new form of competition now arises from the climax
dominants (ride supra \ arising in the community.
I hope to show in later papers that the decline in the adult population of A.
ni(/ra is associated with the increasing dominance of these climactics and I believe
that this is largely a question of competition for food from the more efficient
stolidobranchs and sponges, while chemical effects from sponges may also be a
contributors factor I < ioodbody. 1'Hdb). Support for the contention that competi-
tion for food is important at this stage i> given by the observation that at all stages
of growth .-/. nit/ni maintains its siphons projecting beyond the rest of the com-
munity and usually dies when this is no longer possible. This competition for food
will also affect young .settlers unless they establish themselves in peripheral portions
of the community. Competition tor .space is of course also of great importance at
this stage, as almost all available surfaces are now occupied. I lowever, as the climax
is approached the weight of material in the community increases and sloughing of
small areas of the community occasionally takes place, exposing bare areas of panel.
Sloughing of this sort is natural in old sessile communities ( McDougall, 1943;
I loodbody. l>f>3b) and effectively provides renewed conditions for serai succes-
sion. Bowever, in the communities under study it was noted that unless the
bared area mounted to about 30 sq. in. (which was seldom the case) no new
BTOLOCV OF ASCII) I. \ XIGRA
131
TAHI.E II
The number of new Ascidia nigra appearing each month in all populations, in relation
to the number of panels exposed. For details see text
Month
No. exposed
panel sides
No. new
colonizers
No. colonizers per
exposed ijam-1 -idr
Jan., 1960
8
10
1.25
Feb.
8
2
0.25
Mar.
16
4
0.25
April
16
5
0.31
May
16
3
0.19
June
16
4
0.25
July
24
7
0.29
Aug.
24
8
0.33
Sept.
32
3
0.09
Oct.
32
6
0.18
Nov.
40
78
1.95
Dec.
40
78
1.95
Jan., 1961
40
56
1.40
Feb.
40
28
0.70
Mar.
40
9
0.22
April
40
17
0.42
May
32
11
0.34
June
40
12
0.30
July
40
3
0.07
Aug.
40
10
0.25
Sept.
40
13
0.32
Oct.
40
22
0.55
Nov.
40
38
0.95
Dec.
40
33
0.82
Jan., 1962
40
28
0.70
Feb.
40
9
0.22
Mar.
40
3
0.07
primary colonization occurred and the space was rapidly overgrown by adjacent
sponges. Thus, we find that in these later stages of serai succession competition
for both space and food, coupled with possible substances secreted by sponges, all
combine to inhibit further immigration into the population of A. nujra.
Examination of Table I shows that in the months of November to January
there is an increase in the number of new immigrants into the population, particu-
larly in the first winter, 1960/61. This is best illustrated by expressing the data
as the number of new immigrants per panel side exposed. In such an analysis the
newly immersed panels must be excluded and hence only data from panels im-
mersed for three months or longer are used. Data from population C are not used
at all as the population suffered damage from an early stage. In May, 1 ( >(1. data
from population D are excluded as we know that the increased rate of colonization
there was due to exceptional sloughing of the community. The remaining data are
analyzed in Table II and Figure 1 and clearly illustrate the increased immigration
rate in mid-winter. I have shown elsewhere (Goodbody, 1961a) that Ascidia
nii/ra breeds throughout the year but has a maximum of reproductive activity and
larval settlement in the winter months, and it seems tolerably certain that the in-
crease in immigration into the population in November to January is the result of
132
IVAN - 'I. BODY
a massive increase in tin- number of larvae available, with a consequent increase
in the number of ascidians successfully colonizing in the populations.
It will be noted that population K differs in two respects from other popula-
tions. First the initial coloni/ation by SO ascidians in the first two months \vas
small, and second there was a large additional colonization of 114 animals in No-
vember January, 1960/61. The panels on which this population developed were
first immersed in June. 1 ( '6(), and the small initial settlement is in keeping with
earlier findings ((ioodbodv. 1'^da) that the intensity of larval settlement is minimal
at this time of the year. The high level of secondary colonization is due to the com-
bined effects of the mid-winter abundance of larvae and an early retreat and frag-
mentation of tlu' fiidciiinuiii community. It is usual in these communities for the
/ >!(lciiiiniiii to be replaced by sponges immediately but, for reasons which cannot at
present be explained, the / lidcin mini associated with population E retreated rather
suddenly in November, 1 () (>0. and was not immediately replaced by sponge. As it
fragmented and retreated it left fresh surfaces available for colonization by A. nigra
which established itself before the I tidcin mini grew back or was replaced. This
exceptional circumstance might be considered seriously to bias the figures given in
Table II and Figure 1. so that it is necessary to point out that the total picture is un-
affected by the data from population E. If we re-analyze the data in Table II for
.November and December, 1 ( >6(). and January, 1961, excluding the data for popula-
tion E, we arrive at the following figures for the number of colonizers per exposed
panel side: November, 1.19; December. 1.19; January, 0.7. These figures still in-
2-Ch
05-
J FMAMJ JASONDJFMAMJJ ASONDJ FM
I960 1961 1962
'KK 1. C'lilonixation l>y . l.v< /'<//</ ni</ni in eaeh month, expressed as the numliiT <>f iu'\v
individuals appearing per panel sid< exposed. For fnrilu-r details M-e text and Table II.
BIOLOGY OF ASCIDIA NIGR \ 133
dicate a higher rate of immigration in the mid-winter months than at other times
of year.
In conclusion the data presented in this paper demonstrate beyond doubt that
Ascidia nigra is a primary colonizer in the sessile community in Jamaica. Settle-
ment occurs on clean surfaces at a time when barnacles and filamentous algae are
also colonizing. Subsequently a rapid development of the colonial ascidian,
Didcniniun conchy liatum, overgrows the panel surface, succeeding the barnacl<-~
and algae as the dominant organism in the community. Very small specimens of
A. nigra are smothered by this growth (Goodbody, 1963a) which also inhibits any
further settlement of the solitary species. Individuals of A. nii/ra of more than
about two weeks old can survive the overgrowth and continue to grow in association
with the Didciiinitin, so that at this stage it is a competitor for space and not for
food which controls further immigration into the population. Later in the develop-
ment of the community the Didciiinitiii is replaced by sponges, lamellibranchs and
stolidobranch ascidians, all of which may effectively compete for food with A. nigra,
Thus, in the climax community inter-specific competition for food and space is re-
sponsible for preventing further colonization by A. nigra. A few specimens of A.
nigra, however, succeed in colonizing at all stages of serai succession. This mav
occur either when sloughing of the community provides new surfaces for coloniza-
tion or when larvae settle in peripheral positions in the community where competi-
tion for food is less intense.
SUMMARY
1. Artificial panels were used to allow six populations of Ascidia nigra to de-
velop and grow naturally. The six populations started life at two-month intervals
over a period of a year.
2. With the exception of a population starting life in June, all populations had
dense colonization in the first two months after immersion of the panels, but few
new colonizers in subsequent months.
3. The paucity of new colonizers after initial colonization is due to competition
from other sessile organisms, first for space and later for food.
4. In the months November to December there is a marked increase in the num-
ber of new colonizers, irrespective of the age of the population. This is due to a
large increase in the number of larvae available for settlement.
LITERATURE CITED
GOODBODY, I., 1961a. Continuous breeding in three species of tropical ascidians. Proc. Zool.
Soc. London, 136: 403-409.
GOODBODY, I., 1961b. Inhibition of development of a marine sessile community, \\itnrc, 190:
282-283.
GOODBODY, I., 1962. The biology of Ascidia ni</ni (Savigny). I. Survival and mortality in an
adult population. Bio!. Bull., 122: 40-51.
GOODBODY, I., 1963a. The biology of Ascidia nnjra (Savigny). II. The development and
survival of young ascidians. Binl. Bull.. 124: 31-44.
GOODBODY, I., 1963b. Population studies on a tropical ascidian. /'roc. XI 'I. Intermit. Coni/r.
Zoo!., 1: 113.
GOODBODY, I., 1963c. The development of a tropical marine sessile community. Bull. Ecol.
Soc. Aincr., 44: 92.
McDoucALL, K. D., 1943. Sessile marine invertebrates at Beaufort, North Carolina. Ecol.
Monogr., 13: 321-374.
STUDIES ON SPERMATHECAL FILLING IN AEDES
AKGYPTI (LINNAEUS). I. DESCRIPTION 1
JACK COLVARD JONES AND RONALD E. WHEELER 2
/ V/ 1 !/'-/;;/!';// of fiiitonioloiiy. (.'nri'crsity of Maryland, College 1'tirk, Maryland
In a study on the female reproductive system of C'ule.r pipiens, Kulagin (1901)
illustrated for the first time a flask-shaped sac opening into the vagina, but he
mistook it for the accessory gland. Not having seen Kulagin's study, Christophers
(1923) clearly recognized that the accessory gland of mosquitoes \vas a separate
structure from the dorsal diverticulum of the vagina and he termed this sac the
('(teens. Brelje (1924), apparently unaware of Christophers' work, pointed out
Kulagin's error and described and illustrated the connections between the accessory
gland, bursa copulatrix, spermathecae, and vagina in MocJilony.v, Cttle.r, Citliseia,
and Acdes. He termed the dorsal diverticulum of the vagina the bursa copulatrix.
Brelje also discovered that the male mosquito deposited seminal material into this
sac. Christophers ( 1 ( ">0, p. 67 ( ' ) stated in his monumental work on Acdes acgypti
that "the coccus ... is a relatively small structure with the characters of a mucus
gland," thus repeating Kulagin's confusion of two very different organs. In 1957
Burcham rediscovered both the structure and function of the bursa in Aedcs and
subsequently located Brelje's paper. Unfortunately Burcham's thesis was not
published. Not having seen the earlier work, Hodapp ct a!. (1960) again redis-
covered the structure and function of the bursa of Acdes. Some of this curious
history was brought to light by Curtin and Jones (1961).
It has been known for a long time that female mosquitoes store sperm within
from one to three spherical organs called spermathecae (Dufour, 1851), but it was
not until 1957 that Hurcham first explored some of the problems of how the sperm
reach the thecae. He stated that a few sperm reach the storage organs within
one minute after coitus, and he noted that few to numerous sperm were present
within them in two minutes. He further remarked (p. 80) that the number
". . . steadily increased up to about five minutes after coitus" and that "the
bursa copulatrix was essentially emptied within five minutes after mating."
Schwartz ( 1 ( ">1 i found that sperm reached the thecae of A. acgvpti between the
40th and 15(>th seconds after coitus. Spielman (1964), working with the same
species, reported that sperm do not reach the thecae during the first 30 to 35
^crouds after coitus but fill the organs in a period between 40 and 300 seconds.
It is the purpose of this paper to IM\V a more detailed description of spermathecal
filling in A. uc</ypti (Bangkok strain) than is currently available. A subsequent
paper will deal with some of the physiological aspects of filling.
1 This research was sponsored by \.1.H. Oant GM-06021 and by N.I.H. Development
Award No. K-3-< i.\!-21,52 ( ^ to the first author. scientific article' number A 1180, contribution
number .Vol of the Maryland Agricultural Experiment Station.
'hi. Wheeler's address is I !i, ,1, >^ical Research Laboratory, Ortho Division, California
Chemical Company, Lucas and Ortho Way, Richmond, California.
L34
SPERMATHECAL FILLING IN AEDES 135
MATERIALS AND METHODS
The mosquitoes were reared in an insectary at 26 to 29 C. with a relative
humidity ranging from 70% to 80%. The eggs were hatched in freshly boiled tap
water that had reached room temperature and approximately 100 larvae were
pipetted into a stender dish containing 250 ml. of water and a small pellet of
Purina dog chow. When the larvae pupated, the pupae were sexed by placing them
laterally on an ice cube and examining the pronounced differences in their external
genitalia. The pupae were pooled in a beaker of water according to sex and
placed in a one-cubic-foot screened cage so that the sexes would be completely
the majority of the females were not offered a blood meal. Most of the studies
were made on 3- to 7-day-old virgins. In the great majority of the experiments,
the mosquitoes were forced to copulate by the technique of McDaniel and Horsfall
(1957). Wheeler's modification (1962) of this technique proved essential to
many of the observations required. Adults were generally anesthetized with
applied to the head of Ward's #1 or #2 insect pin and gently but firmly pressed to
the dorsal surface of the thorax. A series of males and females were thus arranged.
The female-bearing pin was inserted into a cork glued to a microscope slide and the
preparation placed under a dissecting stereo-microscope. The male-bearing pin
was inserted into an adjustable holder allowing for gross and fine vertical move-
ments. The male was moved up and down until his terminalium came into contact
with that of the female at an angle of about 90.
Dissections were made by grasping the thorax of the mosquito with sharpened
Dumont #5 microforceps and the terminalium was placed into a small drop of
buffered Drosophila saline (Ephrussi and Beadle, 1936). One finely sharpened
needle was used initially to extract the organs to be studied. Further dissections, if
needed, were made using two needles. Some extractions were made by using
a second pair of microforceps to pull out the desired organs. Further experimental
details are given in the text.
RESULTS
1. Efficiency of spcnnathccal filling after forced-copulation
Virgins of the Bangkok strain force-copulated from 4 to 221 seconds and
averaged 31.3 seconds with a standard error of 1.6 seconds (132 observations).
In 18 cases which were allowed only one to five seconds of coital contact, only one
was inseminated. In 8 cases which were allowed 9 to 10 seconds of coital contact,
five (62^r) were inseminated. In 23 cases which were allowed 15 seconds coital
contact, 21 (91.3%) were inseminated.
Out of 737 cases of forced-copulation, the bursae in 8 females were observed
to have what appeared to be only male accessory gland material and no visible
spermatozoa. Three of these cases could be accounted for because the male
used was found to be sterile and had no sperm cells available. Nevertheless, this
agametic male copulated readily with 6 females in rapid succession. In two
other cases, a male's freshly isolated terminalium had been used to copulate intact
females. But three of the cases could not be accounted for, which presumably
136
JACK COLVAK1) JONES . \D RONALD E. WHEELER
indicates that on rare occasions a normal male- can ejaculate only accessory gland
material.
Both sperm and male accessor) inland material were present in all hnrsae of 41
(82%) of 50 female.s which were force copulated and in all hut one, sperm reached
the spermathecae. < )f these. 41. 5' , had sperm in all three thecae, 48.8% had
sperm in two thecae. and ( '.7' , had sperm solely in the large median theca.
During the first 10 minuter alter forced-mating, sperm moved about within the
thecae of all females examined i 28 cases; 44 thecae with sperm). In those females
which were dissected 30 minutes to 6 hours after forced-mating, sperm moved in
TABLE I
The extent a ml decree of spermathecal filling and moti/ity of stored sperm in Acdes aegypti
after different periods of unrestrained muting. Ten females used for each period
Law spermatheca
Lateral spermatheca
Lateral spermatheca
Bursa
Time
Mr, ,11
degree
coitus
tliecal
filling
No.
Degree
No. with
motile
No.
Degree
No. with
motile
No.
Degree
No. with
motile
No.
Condition
sperm
sperm
sperm
3 hrs.
2.70 +
10
4 +
3
10
3 +
3
10
1 +
3
10
Distended
6hrs.
2.6.? +
10
4 +
1
8
3 +
2
9
1 +
2
10
Distended
2
2 +
2
1
2 +
1
24 hrs.
2.70 +
10
4 +
8
10
3 +
8
10
1 +
10
10
1'artially
distended*
48 hrs.
2.57 +
9
4 +
10
10
3 +
10
8
1 +
8
3
Partillly
1
3 +
distended*' 1
72 hrs.
2.70 +
10
4 +
10
9
3 +
10
6
1 +
8
10
Empty
1
4 +
2
2 +
* Some sperm present in 50' , of Imrsae; undulations of sperm seen in only one hursa.
** A few sperm seen in one bursa.
, to 62of the thecae containing them (20 females; 56 thecae with sperm). T \\entv-four hours after forced-mating, sperm were active in 80' V' of the thecae containing them (5 females; 10 thecae with sperm). 2. Efficiency <>}' spermathecal lillni</ with cage-copulated niostinitoes Using Spiclman's technique (1 ( 'M), individual virgin females of the Bangkok strain were introduced into a 4 :< () in. lantern chimney containing a number of nnmated males, in order to obtain information on the time required for normal mating to begin, and to determine the time of coital contact under Iree mating conditions. The chimncv was shaken to stimulate flight and copulation. In 5 cases, 13 to 32 seconds elapsed before copulation occurred (mean of I'). 4 seconds). The mating time under these conditions ranged from ( '.5 to \(> seconds, with a mean of 13. J seconds. Ten seconds of coital contact under fret- mating conditions usually resulted in insemination. The mean coital time of 13.2 seconds is in close agree- SPERMATHECAL FILLING IX AEDES 137 merit with Spielman's value of 13.7 seconds lor the Johns Hopkin> strain of A. acgypti. Using larger cages, Roth (1948) and ISurcham (1957) obtained a mean coital time value of about 16 seconds. Three-day-old unmated males and females, 10 of each, were placed in each of five one-cubic-foot cages, and allowed to copulate freely for 3, 6, 24, 48, and 72 hours. The females were dissected and the condition of the bursae, the extent and degree of filling of the three spermathecae, and the motility of the stored sperm were noted. The degree of filling was qualitatively judged as follows : 4 +, numerous sperm ; 3 +, many sperm ; 2 +, few to many sperm ; 1 +, very few sperm ; and 0, no sperm detectable. The data for the five groups are summarized in Table I. Of the 50 females examined, 92% had sperm in all three thecae and 8% TABLE II Copulatory behavior and potency of a single six-day-old male Aedes aegypti when offered 12 virgin fenales in a 20-minute period Virgin female number in order of presenta- tion to the male Seconds of coitus Notes 1 10.2 Female escaped after coitus 2 13.6 Bursa full; 2 thecae with sperm 3 14.2 Bursa partially filled; 2 thecae with sperm 4 22.4 Bursa partially filled ; 1 theca with sperm 5 10.8 Female dislodged the male; female not inseminated 6 68.0 \ ninseminated 7 13.8 Female dislodged male; female not inseminated 8 25.8 Uninseminated 9 Male repeatedly attempted to clasp female's terminaliurn but aedeagus did not erect 10 22.8 Uninseminated 11 Male repeatedly erected aedeagus but did not establish good genital contact; Uninseminated 12 Male erected aedeagus but only feebly clasped female's cerci and did not establish good genital contact had sperm only in two thecae. Numerous sperm were in the large median theca in 98% of the cases, 94% had many sperm in one lateral theca. and 84 c /c had a few sperm in the other lateral theca. One to 6 hours after free mating, sperm were actively moving in 26.7% to 33.3% of the thecae containing them (30 females; 72 thecae with sperm). After 24 hours, 86.7% of the thecae contained active sperm (10 females ; 30 thecae with sperm ) . After 48 and 72 hours, sperm were active in all of the thecae containing them (20 females; 56 thecae with sperm). It is evident that data from forced-mating of virgins are significantly different from data from unrestrained or free mating between virgins. Thus, coitus lasts about twice as long with forced-mating, and the extent of insemination and thecal filling is more variable with forced than with unrestrained matings. Furthermore, sperm within the thecae become active more rapidly following forced- mating. The reasons and significance of such differences are not clear. 138 JACK COLVARD JONES \NTJ RONALD K. WHEELER 3. Potency of indk'idinil nnilcs and spermathecal filling Each of live previously miniated males which were 6 days old were offered 4 to 12 virgin female- in succession within a 10- to 20-minute period, using the forced-copulation technique. These males successfully copulated with 4 to 9 females and inseminated 3 to 5 of these. Data on one male which attempted to copulate with 12 females in a 20-minute period are shown in Table II. This individual was able to establish good genital contact for 10 to 68 seconds with 9 females, at least three of which he inseminated. \Yhen this male was subsequently dissected, his accessory glands appeared essentially like those of a once-mated male, but his seminal vesicles were shrunken and possessed only a few spermatozoa. As il- lustrated by the data in Table II, copulation can occur without insemination and even prolonged coitus (as with female #6) does not necessarily result in insemi- nation. Erection of the male's aedeagus was not necessarily followed by copulation (as with females 11 and 12, Table II). In an earlier study (Jones, 1961), it was shown that when virgin males are allowed to copulate freely with a great excess of females in a cage for one hour, they inseminate about five females and their seminal vesicles are usually completely devoid of sperm and their accessory glands are greatly reduced in diameter and have little secretory material. This is in striking contrast to the repetitively force-mated males which only rarely get rid of all the seminal vesicle sperm and apparently ejaculate much less accessory gland material into the females. Conceivably, this difference in the amount of accessory gland material in the ejaculate could account for some of the differences already noted in the last section. Two unmated males were presented to 6 virgins each and allowed to force- copulate with each one for 15 seconds, and the females were then dissected after 23 to 69 seconds. The first male inseminated 4 of the 6 females. The single, large, median spermatheca in all 4 of the 6 females had few to numerous sperma- tozoa; three of the females additionally had one of the lateral thecae with few to numerous spermatozoa. The second male inseminated 5 of the 6 females. Very few to numerous spermatozoa were found in the median theca in all 5 cases. Four of the females additionally had a few sperm in one lateral theca. In all of the above cases, the sperm in the thecae were inactive. 4. Xnuihcr of spei'iinilozou in the reproductive s\stcin Some preliminary estimates on numbers of spermatozoa were made on different portions of the male and female reproductive systems after forced-mating, using squashed whole mounts stained with aceto-lacto-orcein after Carnoy fixation. Sperm heads took the stain strongly and these were counted at a magnification ot 970 >' with the aid of an ocular grid. The inherent counting errors are considered large because the sperm often failed to spread evenly and this failure was especially evident with spermathecal squashes. V- shown in Table III, the terminal testicular chamber of one unmated male had approximately 700 spermatozoa. The terminal testicular chamber of three repetitively force-mated males had from 333 to 120'' spermatozoa (mean of 741.3). The sperm duct (vas deferens plus vas effereus i of one unmated male had 370 spermatozoa. The seminal vesicles of three nnmated males had from 3700 to 6309 SPERMATHECAL FILLING IX AKDES 139 sperm (mean of 5132.3), while the seminal vesicles of two repetitively force-mated males had from 485 to 1374 sperm (mean of 929.5). The bursae of 6 females which were freshly inseminated by a single highly potent male (he force-copulated in rapid succession with 7 females) were dissected within one to two minutes after each ejaculation. This one male ejaculated 254 to 2655 spermatozoa, and progressively fewer sperm were released with each succeeding forced-copulation (Table III). In sum, this male delivered 6126 sperm to 6 females and he did not inseminate the seventh female. TABLE III Numbers of spermatozoa in aceto-lacto-orcein squashes of different tissues of Aedes aegypti Tissue No. cases Estimated numbers of spermatozoa Terminal chamber of testis of unmated male 1 700 Terminal chamber of testes of repetitively, force- mated males 3 333; 682; 1209 (mean, 741.3) Sperm duct of unmated male 1 370 Seminal vesicles of unmated males 3 3700; 5388; 6309 (mean, 5132.2) Seminal vesicles of repetitively force-mated males 2 485; 1374 Bursa 1 to 2 minutes after: First ejaculation 3 1142; 1744; 2655 (mean, 1847) Second ejaculation 1 554 (?) Third ejaculation 1 1248 Fourth ejaculation 1 937 Fifth ejaculation 1 478 Sixth ejaculation 1 254 Bursa 1 to If hours after first ejaculation 3 377; 584; 1142 (mean 701.0) Bursa 1 to 1 hours after second ejaculation 1 119 Spermathecae Large 4 1 H ; 319; 325; 600 (mean, 346.3) Small 4 68; 200; 250; 500 (mean, 254.5) Thecae from 6 females after first ejaculation and 1-1 1 hrs. after copulation 10 73-400 (mean 225.5) The spermathecae of four females were dissected about one hour after forced- copulation with previously unmated males. Counts of spermatozoa in the large median theca varied from 141 to 600 (mean of 346.3), and counts of spermatozoa in one of the lateral thecae varied from 68 to 500 (mean of 254.5). Other counts made on spermathecae of unspecified size ranged from 73 to 400, with a mean of around 226. The bursae of three females were dissected one to 1^ hours after forced-copulation with fresh unmated males. The number of spermatozoa that remained in the bursa after thecal filling had occurred was estimated to vary from 377 to 1142 (mean of 701) (Table III). These counts are considered to be much more reliable than direct spermathecal counts and suggest that of 1847 sperm (Table III) deposited in the bursa, about 1146 (62%) can reach the thecae. This, in turn, suggests that about 660 sperm reach the large theca and about 486 reach one of the lateral thecae. If these suggestions are correct, then the direct thecal counts of sperm are in error by a factor of about 2. 140 .1 U"K COLVARD JONES \VI> K<>\ \l.l> K. WHEELER From these various estimations llic following suggestions can be made. (1) The miniated male has about 5000 sperm available within his seminal vesicles. After rapid repetitive forced -mating, the male can ejaculate ahout S_" ', of the sperm within his vesicles. ( _' ) The male ejaculates progressively fewer spermatozoa into each successive female, i 3 ) Sixty-two per cent of the sperm initially deposited in the bursa reach the thecae. and oS' ', remain in this sac immediately after thecal filling. Cr FIGUKK 1. Sagittal section of Acdcx nc</ypti female immediately after ejaculation of the male, showing llie seventh (VI It and eighth (VIII) abdominal segments, cerci (CK), upper genital lip (UGL), bursal orifii-c (BO), accessory gland duct (AGD), spermathecal eminence (SI-".), dorsal valve (DV), ventral vaginal valve (W), and spennathecae (S) of the female. Note the spermatozoa (SI*) in packets in the dorso-anterior portion of the bursa and the large amount of finely granular male accessory gland secretion. The phallotreme of the male is shoun at IT. 5. 1 lie composition <>j the ejaculate The normal ejaculate consists of a relatively small amount of spermatozoa and a much larger amount of an acidophilic holocrine secretion of the male's accessory glands. I "rcsumablv, the spermatozoa are contained in a small volume ot fluid within the seminal vesicles, and it is assumed that some' of tin's seminal fluid is added to the ejaculate. When the ejaculate is seen under the dissecting microscope, it appears whitish ; when viewed with a compound microscope, it has a greyish yellow cast. SPERMATHECAL FILLING IN . \KDES 141 The male accessory gland secretion includes a clear to finely granular material, round to ovoid granules of at least three different sizes, a few free nuclei, and even some intact, round to ovoid accessory gland cells of various sizes with large granular inclusions. If the accessory glands are ruptured in an open drop of saline, the exuding material does not usually vacuolate and the cells, free nuclei, and granular inclusions do not ordinarily lyse, although the cells may become swollen. Tin accessory gland secretion in an open drop of saline forms a dense, viscous, sticky mass which will rapidly clog a micropipette. However, if the saline mount is quickly covered with a layer of immersion oil before the glands are ruptured, then the exudate can be generally drawn into a micropipette without clogging. B FIGURE 2. Sagittal section of Acdcs acyypti female during spermathecal filling. In A i> shown the upper genital lip (UGL), the swollen bursa (BO, the vestibule (V), the sperma- thecal duct (SD), and the dorsal vaginal valve (DV). B is the same section, at greater magnification, showing the sperm (SP) assembled in packets on the ventral floor of the bur>a. and sperm making the U-turn into the vestibule. Note the position of the accessory gland duct (AGD), one spermathecal duct (SD), the posterior vaginal valve (PV), dorsal vaginal valve (DV) and ventral valve (VV). The transverse muscles of the spermathecal eminence are shown at TM. 6. Sonic changes in the ejaculate "^ the bursa At the very moment of deposition, the locomoting packets of sperm are ejected dorsally above the accessory gland secretion (Fig. 1). Tn sagittal sections, the freshly inseminated bursa measures about 300 to 350 /A in length and varies from 78 to 100^ in depth. The bursal orifice measures from about IS to 25 /JL. The spermatozoa measure about 250 /A (Christophers, I960). \Yhile most of the sperm rapidly spread to the edges of the bursa. .some of them become trapped in the granular portion of the accessory inland secretion. As Spielman (1964) has pointed out, many sperm rapidly assemble on the ventral wall of the bursa facing 142 JACK COLVAKI) JONES \VD RONALD E. WHEELER the orifice ( l r ig. 2\\, SI' ). Those sperm at the 1)liiul anterior end of the bursa tend to remain quite active lor about 17 minutes in oil-covered drops of saline, after \vhich they tend to become noticeably less visible and less active. Those sperm at or near the bursal orifice tend to he especially active. Thirty seconds after ejaculation, the bursal wall in sagittal sections measured -.2 to 3.3 p.. Two to three minutes after insemination, the bursal wall was greatly swollen (7.5 to !_' // thick ), hyaline, and the cells had large colorless vacuoles. The bursal wall was swollen and vacuolated for at least one hour after insemination. In fresh unstained whole-mounts of freshly inseminated bursae, we have seen what appeared to be a very delicate membrane surrounding the seminal mass, but no such membrane was visible in any of the histological sections. 3. Unstained saline whole-mount dissection of the bursa of Acdcs ac</ypti about 10 minutes after insemination, showing the fully vacuolated ejaculate. Note the swollen wall (W) in A and, at greater magnification (B), the large vacuoles and granules within the ejaculate. The largest vacuole in I', is about 20 microns in diameter. Three to live minutes after insemination, large vacnoles hrst appear within the granular portion of the ejaculate and they steadily increase in number until the bursal contents become filled with vacuoles within a granular matrix (Fig. 3). The large vacnoles measure about 20 /j. in diameter. These vacuoles are very clear in whole mounts but may be indistinct in sectioned material. The ejaculate may be fully vacuolated within about 10 minutes at 27 C. At 3(> to 37 C., the bursal contents fully vacuolate in about one minute. The completely isolated, freshly inseminated bursa will fully vacuolate in a drop of saline covered with a laver of immersion oil. When a male's accessory glands were crushed in the vicinity of the freshly dissected virgin bursa, the glandular exudate did not vacuolate. Tl the female is hosed with carbon dioxide for 5 minutes three seconds after coitus, the seminal material within the bursa does not vacuolate. SPERMATHECAL FILLING IN AEDES 143 In many preparations in which the bursal contents we.'- vacuolating or had already fully vacuolated, the sperm were not visible through the intact wall of the bursa, but when the bursa was opened, sperm were found, r.ursal sperm retain a highly variable amount of undulatory activity for about 6 hours and sometimes for as long as 24 hours after insemination. In a number of cases, however, the sperm within the bursa were mostly inactive within about 75 minutes after ejaculation. Bursae rilled with vacuolated seminal material were observed up to 6 hours after insemination. Twenty-four hours after insemination, the bursae were partially distended; the wall was no longer thickened and vacuolar, and the contents of th<- sac were finely granular, had a yellowish brown cast, and were devoid of any vacuoles. The bursa was never observed to contract in saline or oil-covered saline preparations of either uninseminated or inseminated A. aegypti. Histological sections showed the bursa to be completely devoid of muscles. 7. Structure of the spermathecae and tlicir ducts The median spermatheca of A. aegypti measures about 100 /x. in diameter, and each lateral theca measures approximately 75 p, in diameter. The thecae are completely devoid of muscle and were never observed to contract in any type of preparation examined. When the spermathecae of virgins are opened under a deep layer of oil, no bubble escapes. When the thecae are crushed in a drop of xylene containing sudan black, a colorless halo of fluid appears immediately around them. This colorless watery fluid within the thecae did not react with phenol red, neutral red, sudan III, British Drug House Indicator, or with Hydrion papers. Although the spermathecal ducts are covered by a single layer of evenly spaced circular muscles ( Curtin and Jones, 1961), we have never seen these ducts contract in saline or oil-covered saline whole-mounts. The spermathecal ducts, when stretched out in saline, measure about 265 p. in length, and the clear lumen of these varies from about 2 to 3.5 p.. 8. Speed of sperm transfer Twenty-two females \vere used to study how rapidly bursal sperm could reach the thecae after forced-mating. The females copulated with males for 9 to 54 seconds and were immersed in liquid chloroform 2 to 45 seconds thereafter. Three of the females did not become inseminated, although the males had copulated with them for 9 to 25 seconds. Eight of the females were killed 2 to 24 seconds after coitus and in three of them (37.5%), sperm had reached the thecae. In the first of these three cases, the female (which had copulated for 53. 8 seconds and was killed in 18 seconds) had only a very few sperm in two thecae. In the second case, the female (which had copulated for 28 seconds and was killed in 20 seconds) had many sperm in the large theca and a few sperm in one lateral theca. In the third case, the female (which had copulated for 15 seconds and was killed in 24 seconds) had only a few sperm in the large theca. In the five other cases, however, sperm were found only in the bursa and none reached the thecae. Eight out of the 22 females were immersed in chloroform 30 seconds after coitus and were 144 | \CR (Oi \ \RD JONE5 \l) RONALD E. WHEELER then dissected. In onl\ one of thes< females had sperm reached the large median theca. The last three females were killed 40 to 45 seconds after forced-mating, and in all three case's mam sperm had ascended to the thecae, and in two of the females sperm were in two thecac. Thus, following- uninterrupted forced-coitus, while a few sperm apparently are capahle of reaching the thecae of a few females as early as IS seconds after copulation, in most cases the sperm begin to till the thecae between 30 and 45 seconds. That highly variable results can be obtained is shown by the following data. Coitus of 7 pairs was permitted for exactly 15 seconds, after which the females were killed at 10-second intervals from 30 to 90 seconds after forced-mating, by exposing" them to very strong ether fumes. Only a few sperm reached two thecae after 30, 40 and 50 seconds. Many to numerous sperm were found in two thecae after 60, 70, SO and <>() seconds. In spite of the variability of the data, it is evident that spermathecal filling in A. ucf/yf'ti is a rapid event, and we are much inclined to agree with Burcham (1957) and the data presented by Spielman (1*^)4) that no transfer occurs after the first 5 minutes following coitus. 9. Histological observations on the reproductive tract oj inseminated females before, dnrini/ and following spermathecal filling Spielman (l l ^>4) stated (p. 341) that ". . . 5 minutes after coitus, sperm were scarce in the anterior portion of the . . . btirsa'" and that one hour after coitus "the hursa was filled with coarse material and the remaining sperm were compressed into the posterior end and into the upper atrium." Our observations are not in agreement with these statements. The bursae of 22 mosquitoes were dissected 23 minutes to 6 hours after forced-copulation and in all cases many to numerous sperm were still present in the distended bursae. Dr. Spielman has kindly permitted us to examine the sections which he prepared for his studies on spermathecal filling after free mating. Our observations on his material follow. Sections made 30 seconds following coitus showed that the bursa was dis- tended with ejaculate, the majority of the sperm being antero-dorsally located, but at least one dense packet of sperm was seen on the ventral wall of the bursa at its orifice. Xo sperm were observed in either the atrium, vestibule, thecal ducts, spcrmathecae. or common oviduct. The ventral tuft just inside the female's ventral genital lip slanted dorsally into the bursal orifice but did not block this opening. In some sections, the posterior valve of the vagina was pressed against the surface of the dorsal valve, but in other sections a gap of variable dimensions was seen between these two vaginal valves. The ventral valve in some sections was pressed against the dorsal valve. Thirty-five seconds after coitus, sections showed some male accessory gland material within the lumen ot the upper vagina, but no sperm were detected. Numer- ous sperm were still in the dorsal portion of the hursa and at its blind anterior end. Many sperm in the bursa were seen in ventrally-directed arcs. Dense packets of sperm were seen making a sharp I '-turn from the' bursal orifice into the spermathecal vestibule- (see Fig. 2). The heads of these sperm were in contact with the intima ol the spermatliccal ducts. No sperm were visible in the upper vagina, thecae or common oviduct. The ventral tuft slanted upward into the SPERMATHECAL FILLING IN AEDES 145 bursal orifice, blocking the center of it about half way. The spermathecal eminence appeared to be elevated and the vestibular opening seemed shifted into a position dorsal to the ventral tuft. The posterior vaginal valve in some sections was pressed against the dorsal valve. Sections made 43 to 60 seconds after insemination of the bursa showed sperm, and, in one case, male accessory gland material, free in the lumen of the upper vagina (Fig. 2). Many sperm were flattened against the surface of the dorsal vaginal valve. No sperm were visible in the lower vagina or in the common oviduct. The bursa was distended, and many sperm were ventrally aligned in dense packets at the bursal orifice. The median ventral tuft slanted halfway across the bursal orifice. The spermathecal eminence still appeared elevated. Many sperm were seen making the U-turn into the vestibular opening (Fig. 2). Sperm were observed inside two spermathecal ducts, and a few sperm were seen inside the spermathecae. The posterior vaginal valve in some sections touched the dorsal valve. Ten minutes after insemination, sections showed sperm still present in the upper vagina, mostly flattened against the dorsal valve. No sperm were visible in the lower vagina or the common oviduct. Numerous sperm were still present in the bursa and many of them were aligned on the ventral wall at the orifice. The ventral tuft appeared to completely block the vestibule in one series of sec- tions made at 10 minutes. In sections made one hour after coitus, sperm were still within the upper vagina, free in its lumen, and against the dorsal valve ; and for the first time, sperm were seen in the lower vagina and in the lumen of the common oviduct. Numerous sperm were still observable throughout the distended bursa. The vestibule appeared fully open to the bursal orifice. The ventral tuft did not block the vestibule. Sperm were still detectable within the spermathecal ducts and within two thecae. Sperm were especially dense at the entrance to each of two thecae. According to Spielman (1964, p. 341), the common oviduct contains ". . . masses of agglutinated immobilized sperm" one hour after coitus. Dissections made on the Bangkok strain after forced-copulation showed a few undulating sperm within the common oviduct at 57 to 69 minutes in three females, but no sperm were visible in the oviducts of two other females. Two hours after forced- copulation, one female had undulating sperm in her common oviduct as far as the ampullae, but no sperm were seen in the oviduct of another female dissected at the same time. No sperm were visible in the common oviduct of one female dissected 6 hours after forced-copulation. Our observations indicate that in both freely-mated and force-mated A. aegypti many sperm remain within the bursa following spermathecal filling, and that most of them are not concentrated at the bursal orifice. It is of considerable interest that the female has no anatomical device that could account for the fact that those sperm which are aligned at the open bursal orifice no longer attempt to reach the spermathecal vestibule. Even sperm which are free within the lumen of the upper vagina are no longer oriented towards the vestibule after spermathecal filling. Numerous dissections were made on force-mated and freely-mated specimens 146 JACK COLVARD JONES \XD ROXAI.D E. WHEELER before, during, and following spermathecal filling, and in not one case were sperm ever detected within the spermathecal ducts. It is difficult to reconcile this with the presence of a few sperm in these ducts in sectioned material made one hour after free-mating. It is possible that during dissection the sperm within the ducts quickly entered the spermathecae. 10. The beliavior of spcnnatoza Observations were made on the activity of spermatozoa within various portions of the unmated male's intact reproductive system in oil-covered saline whole- mounts. The spermatozoa often exhibited intense whirling or spiralling activity within the posterior testicular chamber. They were either inactive or showed a highly variable degree of activity within the sperm ducts, and sometimes undulated within the seminal vesicles. Sperm retained activity within the testes for 54 TABLE IV Changes in motillty of sperm with time in thecae isolated from force- and freely-mated Aedes aegypti one hour after insemination. Ten females used for each of the two groups % Thecae with moving spermatozoa Time after isolation of thecae Force-copulated* Freely mated** less than 10 mins. 46.4 33.3 1 hour 85.7 58.3 2 hours 64.3 8.3 3 hours 42.9 4 hours 10.7 5 hours 3.6 * Twenty-eight thecae contained sperm. * Twelve thecae contained sperm. to 270 minutes and undulated in some seminal vesicles for 60 to 348 minutes. Sperm within the sperm ducts, if active at all, were generally active for less than 38 minutes and for not more than 196 minutes. The spermathecae of force-mated and freely-mated mosquitoes were isolated one hour after copulation in a drop of saline and the preparation covered with a layer of immersion oil so that the activity of the sperm within the thecae could be noted at hourly intervals. As shown in Table IV, sperm were generally more active and remained active for a longer period in the force-mated than in the cage-mated group. While no activity was observed three hours after isolation of the thecae from the cage-mated mosquitoes, sperm were actively moving in 42.9% of the thecae of the force-mated females at this time. The following types of activity were observed in spermatozoa released from seminal vesicles into a drop of saline covered with a layer of immersion oil : (1) very rapid locomotion with the short, sharp, thin, stiff, needle-like head piece tilting up and down as the long thin tail made rapid, large wave undulations. These explosive progressive locomotory movements occurred either in a generally straight line in any direction, or the sperm would circle about briefly. In saline drops SPERMATHECAL FILLING IN AEDES 147 which were not covered with a layer of oil, locomotions were only rarely observed. (2) Very rapid and intense coiling or lashing motions of the tail were observed, especially when the sperm occurred in clusters and when the head was at an inter- face. Many times the tails of clustered sperm whirled or lashed synchronously. (3) Slow, smooth, regular, large wave undulations of the tail were observed when sperm were congregated at the saline/oil interface. (4) Irregular undulations or oscillations of highly variable amplitudes were observed in sperm which had ceased locomoting or which had stopped the smooth regular undulations. Different por- tions of the tail were capable of undulating at very different rates and with differ- ent amplitudes. The waves moved away from the head piece. Observations were made on the activity and survival time of sperm released from the seminal vesicles. Highly variable results were obtained, depending upon the technique and the location of the sperm within the preparation. When the seminal vesicles were ruptured into an open drop of saline, many sperm which reached the edge of the drop quickly lost their motility in one to three minutes. Those sperm which did not reach the edge of the drop undulated irregularly and lost all activity fairly rapidly. However, those sperm still inside the torn vesicles tended to remain active for about four minutes in open saline drops. When the vesicles were ruptured in a very small amount of saline that had been covered first with a drop of immersion oil, the sperm were often intensely active for two to 15 minutes, especially around the surface of the vesicles. Generally, the sperm in such preparations lost all activity in three to 87 minutes after release. Those sperm which moved out into the layer of oil very quickly ceased moving. When the vesicles were opened in a moderate-size drop of saline that had been covered with a layer of immersion oil, those sperm which were strongly oriented at the saline/oil interface remained active for 16 to 60 minutes, but those which did not reach the edge of the drop tended to lose their activity in about one minute. The sperm inside the seminal vesicles remained quite active for two to 119 minutes (in most cases for about 6 minutes) ; highly variable numbers undulated feebly for 182 to 328 minutes. Sperm on the outside of the vesicles tended to have their heads oriented to the vesicles' surface and were often very intensely active for about four minutes. In coverslipped saline mounts in which air bubbles had been trapped, the sperm head was frequently strongly oriented to the saline/air interface. To study whether chemotaxis might be involved in sperm migration, seminal vesicles and bursal sperm were released in the vicinity of intact male accessory glands, male accessory gland exudate, and onto freshly excised vaginal tissues. In many cases, the tip of the sperm head was strongly oriented to all of these tissues, but sperm did not specifically congregate around them. The head of seminal vesicle and bursal sperm did not become specifically oriented to fat body, testes, somatic muscles, bursa, female accessory gland, or its duct, spermathecal ducts, intact or crushed spermathecae, common oviduct, or even to a freshly laid egg. To determine whether the sperm head would be oriented in or against the direction of a moving stream, the intact seminal vesicles were dissected into a drop of saline on a glass slide next to a long rectangular coverslip supported on two sides by capillary glass rods. The thin space between the coverslip and slide was filled with saline. The seminal vesicles were cut open so that the sperm 148 JACK COLVARD JONES AND RONALD E. WHEELER poured out into the saline just under the edge of the coverslip and a strong current was produced by withdrawing saline at the other end. In all such preparations, the sperm heads were precisely aligned in the direction of the flowing stream of saline. Dead sperm were not precisely aligned. This type of rheotaxis of live Aedes sperm is exactly the opposite of that of bull or human sperm which are known to orient the head piece against the direction of a moving stream (see, e.g., Rothschild. 1962). Thus, the head of the spermatozoon of A. uc</yf>ti becomes oriented toward certain tissues and becomes aligned in the direction of a flowing stream, and the tail piece is capable of propelling the cell rapidly. We are indebted to Dr. Andrew Spielman of Harvard University for allowing us to examine his histological sections and for many stimulating discussions. Our Figures 1 and 2 were taken from material which Dr. Spielman loaned us. We are most grateful to Mr. Kenneth W. Ludlam for his help with many of the experi- ments. Useful suggestions concerning the manuscript were made by Drs. Norman T. Davis, Arden O. Lea, P. T. M. Lum and A. Glenn Richards, and by Elizabeth D. Jones. SUMMARY 1. With the forced-copulation technique, the Bangkok strain of Aedes aegypti can ejaculate within the first five seconds of coitus but usually does so within 10 to 15 seconds. The male force-copulates for 31.3 seconds, and 82% of the females become inseminated. In 90% of them, spermatozoa reach two of the three thecae. With naturally-mated mosquitoes copulation is significantly shorter in duration, all of the females become inseminated and in 92 % of them spermatozoa reach all three thecae. 2. The terminal chamber of the testis of an unmated and repetitively force- copulated male has about 700 spermatozoa. Each sperm duct has about 370 sperm. The seminal vesicles of unmated males have about 5000 spermatozoa, while the vesicles of repetitively force-mated males have about 930. 3. With rapid repetitive force-copulation, the male ejaculates progressively fewer spermatozoa into the bursa of each successive female. Sperm counts made on 6 ejaculates from one male varied from 254 to 2655. 4. Counts on spermatozoa remaining in the bursa after spermathecal filling indicate that 62% of them leave the bursa, and suggest that about 660 sperm reach the large theca and 486 fill one of the lateral thecae. 5. Most of the sperm deposited in the bursa quickly spread to the edges of the sac, and many become aligned on its ventral wall. The wall of the bursa greatly swells two to three minutes after insemination. Shortly thereafter the accessory gland secretion within the ejaculate begins to vacuolate and may be fully vacuolated within 10 minutes and remains vacuolated for at least 6 hours. 6. With forced-copulation, a few sperm may be capable of reaching the thecae within 18 seconds but in most cases sperm begin to reach the thecae between 30 and 45 seconds after coitus. Complete thecal filling can occur in 90 seconds and probably is terminated within the first five minutes or less after coitus. Fol- SPERMATHECAL FILLING IN AEDES 149 lowing spermathecal filling many active sperm remain in the bursa for some time. Following spermathecal filling those sperm at the bursal orifice no longer make the U-turn towards the open spermathecal vestibule. 7. Spermatozoa within the isolated but intact male reproductive system may remain active for five to six hours in oil-covered saline whole-mounts. Sperma- tozoa released from seminal vesicles in oil-covered saline drops exhibit four types of movement: (a) brief, rapid, explosive, progressive locomotion, (b) rapid synchronous coiling when the cells are in dense clusters and the head is at certain interfaces, (c) smooth undulations in situ, and (d) irregular undulations or oscillations. The heads of sperm of Aedes become oriented in the direction of a moving stream. 8. Sperm released from the seminal vesicles may become strongly oriented toward the male accessory glands and its exudate, and to freshly excised vaginal tissues, but they do not specifically congregate about these tissues in oil-covered saline whole-mounts. Seminal vesicle sperm do not become oriented to freshly excised fat body, testes, somatic muscles, bursa, female accessory gland or its duct, spermathecae or their ducts, ovary, common oviduct, or a freshly laid egg. CONCLUSIONS Many sperm deposited in the bursa of female Aedes aegypti (Linnaeus) rapidly locomote around the male accessory gland secretion of the ejaculate and assemble on the ventral floor of the sac at its orifice where they undergo rapid and violent synchronous coiling movements. The strong orientation of the sperm head to certain interfaces presumably guides the long, thread-like contracting cells over a U-shaped route directly into the vestibule where they first contact the opening of the spermathecal ducts. Bundles of sperm swiftly ascend the ducts, presumably only in female fluids, and simultaneously reach two or three thecae. Shortly after sperm begin to fill the already fluid-filled thecae, the bursal wall swells and pre- sumably secretes material into the ejaculate. After this the accessory gland se- cretion of the ejaculate begins to vacuolate, and a short time after this, the still active sperm at the open bursal orifice stop moving into the vestibule. LITERATURE CITED BRELJE, R. VON DER, 1924. Die Anhangsorgane des weiblichen Geschlechtsganges der Stech- miicken. Zool. Ans., 61 : 71-80. BURCHAM, E. G., 1957. Some characteristics and relations of mating and oviposition of Aedes aegypti (Linnaeus) (Diptera: Culicidae). Ph.D. Thesis, Ohio State Univ., 130 pp. CHRISTOPHERS, S. R., 1923. The structure and development of the female genital organs and hypopygium of the mosquito, hid. J. Mcd. Res., 10: 698-720. CHRISTOPHERS, S. R., 1960. Aedes aegypti. The Yellow Fever Mosquito. Its Life History, Bionomics and Structure. Cambridge Univ. Press, 739 pp. CURTIN, T. J., AND J. C. JONES, 1961. The mechanism of ovulation and oviposition in Aedes aegypti. Ann. Ent. Soc. Amer., 54: 298-313. DUFOUR, L., 1851. Recherches anatomique et physiologique sur les Dipteres. Mem. Acad. Sci. Paris, 11:205-210. EPHRUSSI, B., AND G. W. BEADLE, 1936. A technique for transplantation for Drosophila. Amer. Nat. ,70: 218-225. HODAPP, C. J., P. H. SCHWARTZ AND J. C. JONES, 1960. Some observations on the anatomy of the female reproductive system of Aedes aegypti (L.). Anat. Rec., 137: 364-365. 150 JACK COLVARD JONES AXD RONALD E. WHEELER JONES, J. C, 1961. Observations on sexually depleted male Acdes aegypti (L.) Amcr. Zool, 1 : 362. KULAGIN, N., 1901. Der Ban der \\ciblichen Geschlcchtsorgane bei Citlcx und Anopheles. Zcitschr. wiss. Zool, 69: 578-597. McDANiEL, I. N., AND W. R. HORSFALL, 1957. Induced copulation of aedine mosquitoes. Science, 12: 745.
ROTH, L. M., 1948. A study of mosquito behavior. An experimental laboratory study of the
sexual behavior of Acdes aegypti (L.). Amcr. Mid. Nat., 40: 265-352.
ROTHSCHILD, L., 1962. Sperm movement. Problems and observations. In: Spermatozoan
Motility (ed. by D. W. Bishop). A.A.A.S. Publ. no. 72: 13-29.
SCHWARTZ, P. H., 1961. Behavior of spermatozoa in Acdes aegypti (L.). M.S. Thesis, Univ.
of Maryland, 45 pp.
SPIELMAN, A., 1964. The mechanics of copulation of Aedes aegypti. Biol. Bull., 127: 324-344.
WHEELER, R. E., 1962. A simple apparatus for forced copulation of mosquitoes. Mosq. News,
22 : 402-403.
NEW SPECIES OF ACOEL TURBELLARIANS FROM
THE PACIFIC COAST
EUGENE N. KOZLOFF
Lewis and Clark College, Portland, Oregon, and Friday Harbor Laboratories,
University of Washington
The acoel turbellarians have been accorded very little attention in North
America. Only a few species have been described, and some of these will have to
be investigated more completely before their taxonomic position can be estab-
lished with any degree of certainty. On the Pacific coast, where acoels are
abundant in bottom sediments, on algae, and in other situations, apparently only
two species have been named. One of these is PolycJwcrus cannelensis Costello
and Costello (1938), from central California; the other is Childia groenlandica
(Levinsen), an acoel which has a wide distribution in North Atlantic waters and
which has recently been reported from San Francisco Bay, California (Hyman,
1959).
During the summers of 1961 and 1962, and the autumn of 1964, several species
of acoels were taken at various localities on San Juan Island, in the San Juan
Archipelago, Washington. Mature individuals of three of these were recovered
in sufficiently large numbers to permit a thorough study of their morphology
and description as new species. Additional material of one of these acoels was
found at Charleston, Coos County, Oregon, during the summer of 1964.
The acoels are a difficult group with which to work. Most of them are small,
and certain of their syncytial structures are not sharply delimited. Many pub-
lished descriptions are incomplete and poorly illustrated. There are even some
rather detailed accounts which do not focus sharply on pertinent details, and
from which one cannot form a clear picture of the morphology of the acoels con-
cerned. In deciding the taxonomic position of the new species described here, I
have relied upon the summary of the genera and higher taxa of acoels given by
I wish to express my appreciation to Dr. Robert L. Fernald, Director of tin-
Friday Harbor Laboratories, for many courtesies which facilitated my work.
METHODS
The acoels described in this contribution were for the most part obtained by
taking up masses of green algae (Uha and Enter onwrpha) and washing them by
agitation in a pail of sea water. A thin layer of sediment (consisting largely of
muddy sand from the substrate) obtained in this way was then distributed in large
culture dishes, in water about 2 or 3 cm. deep. Samples of sediment sucked up with
a large pipette and examined with a dissecting microscope often contained acoels,
151
152
Krr.KNK N. KOZLOFF
^oCf *^ Sft i *j f **
^ 4t- n^ -^ ^'-^ . ft
f.VS** 1 * 1 **!**
7
Plate I Parotoccllx lulcola
All figures were prepared with the aid of a camera lucida, but in the case of specimens
drawn from life (Kiv 1 S), most details were sketched in free-hand. Figures 6 to 11 are based
NEW ACOELS FROM THE PACIFIC COAST 153
together with rhabdocoels, alloeocoels, copepods, amphipods, and other small
organisms.
My descriptions are based entirely on sexually mature specimens examined
or fixed soon after collection. (Worms which are immature or which are not
well nourished are unreliable.) The acoels were studied extensively in life,
in both transmitted and reflected light. Gentle compression of the worms under
a coverglass was usually necessary to make certain structures clearly visible. Ad-
dition of a small amount of a solution of magnesium chloride (approximately
isotonic with sea water) to the drop of water in which the worms were swimming
was generally helpful in narcotizing them in an extended condition without obvi-
ously affecting their appearance.
Stained whole-mount preparations were less useful than living acoels for
morphological studies. However, a few whole-mounts of worms fixed in Bouin's
fluid and stained with alum hematoxylin or borax carmine were prepared for
permanent records.
The morphology of the acoels described in this paper was worked out largely
by study of transverse, sagittal, and frontal serial sections (6 /* or 8 ft). The
worms were fixed, usually after being narcotized, in Bouin's fluid or in a mixture
of 90 ml. of a saturated aqueous solution of mercuric chloride with 10 ml. of
formalin and 5 ml. of acetic acid, and then embedded in paraffin. Iron hematoxylin
was used routinely for staining ; sometimes the preparations were counterstained
with eosin, orange G, or fast green FCF. A few series were stained with Harris'
alum hematoxylin and eosin.
DESCRIPTIONS OF SPECIES
Parotocelis Iittcola gen. nov., sp. nov.
Most of my material of this acoel was taken in shallow pools at the margins
of a body of water known locally on San Juan Island as Argyle Lagoon (Lat. 48
on sections (6 /u) of specimens fixed in Bouin's fluid and stained with iron hematoxylin ; certain
details were supplied from adjacent sections in the same series.
Abbreviations for all figures : b, brain ; bs, seminal bursa ; ec, ectocytium ; en, endocytium ;
fg, frontal glands ; g, glands surrounding copulatory organs ; ga, genital atrium ; gp, genital
pore ; Id, lipid droplets ; m, mouth ; mp, parenchyma! muscles ; ms, subepicytial muscles ; n, nozzle
of seminal bursa ; ooc, oocyte ; oog, oogonium ; p, penis ; pg, granule-filled masses at tip of penis ;
s, statocyst ; sd, sperm duct ; sv, seminal vesicle ; t, testis ; v, vagina.
FIGURE 1. Specimen in contact with substrate; dorsal view.
FIGURE 2. Rhabdites at left margin of body.
FIGURE 3. Mature sperm.
FIGURE 4. Anterior end (specimen slightly compressed under coverglass) ; dorsal view.
FIGURE 5. Posterior end (specimen slightly compressed under coverglass) ; dorsal view.
The anterior portion of the vagina, in which the lumen is obliterated by a syncytium containing
refractile granules, obscures part of the seminal vesicle beneath it.
FIGURE 6. Frontal section. One of the oocytes is undergoing a maturation division.
FIGURE 7. Median sagittal section.
FIGURE 8. Epicytium, epicytial glands, subepicytial musculature, and portion of testis in
transverse section just anterior to mouth.
FIGURE 9. Transverse section just anterior to mouth.
FIGURE 10. Transverse section through seminal bursa of same specimen.
FIGURE 11. Transverse section through penis, seminal vesicle, and anterior portion of vagina
of same specimen.
154 EUGENE X. KOZLOFI'"
31.3' N.; Long. 123 0.6' \V.i.' The worms are usually abundant in muddy
sand supporting a growth of I'.ntcroinorpha. P. hiteola has also been collected in
small numbers at Friday Harbor, among Ulva and Enteromorpha growing on a
substrate of gravel mixed with muddy sand, at tide levels of about to +2 ft.
\Yhen gliding actively, the length of P. lit t cola is typically about two and a half
times the width (Fig. 1). The greatest width is usually near the end of the first
one fifth of the body. The anterior end is broadly rounded; posteriorly, the
body tapers rather gradually to a nearly acute tip. The largest specimens are
about 700 p. in length and 230 ju. in width, but they may become extended temporarily
to a maximum length of about 840 /*, and a width of about 180 //,. In worms
which are in tight contact with the substrate, the thickness in the mid-dorsal region
is usually about one-half the greatest width, so that the body appears definitely
flattened. When swimming free, the worms become nearly cylindrical.
The statocyst (Fig. 4) lies about midway between the ventral surface and
the dorsal surface, near the end of the first one-tenth of the body. In larger
specimens, the diameter of the statocyst is about 20 p, and that of the statolith is
about 12 fj.. Viewed on edge, the statolith is nearly hemispherical; the convex
surface is uppermost.
In reflected light, the coloration of the body as a whole, excluding the digestive
endocytium, is whitish, tinged faintly with orange ; the orange color becomes more
pronounced anterior to the statocyst. In most specimens which contain ingested
diatoms, the endocytium is green, although in an occasional individual this region
is brown or yellowish brown. In the area just behind the statocyst, there are small
masses of a material which appears white in reflected light. Three discontinuous
longitudinal streaks of this material extend for some distance posteriorly.
In strong transmitted light, the body is more or less translucent. In the
endocytium, freshly-ingested diatoms with their characteristic olive-green, vellow-
brown, or yellow-green color may be seen, together with those which have turned
green or bluish green. Chlorophylls diffusing out of the diatoms undergoing digestion
appear to be responsible for the green or blue-green color typically observed in this
general area. In the ectocytium anterior to the statocyst, there is a crescentic
band of yellowish-orange pigment ; similar pigment is often found in small areas
in the posterior part of the body, around the copulatory organs. Lipid droplets
are scattered throughout the body. The larger of these, which may attain a
diameter of about 20 /*, arc yellow or orange ; the smaller ones may be nearly
colorless, yellow, orange, or bluish green, or some mixture of these colors. The
lipid droplets apparently concentrate pigments which diffuse out of the diatoms.
The material which is white in reflected light is seen to consist of granules or rods
of a refractile substance. These granules form small aggregates (Fig. 4) within
the ectocytium in the dorsal part of the body just behind the statocyst, and dorsal
and dorsolateral to the endocytium. Under low magnification, the aggregates
1 Argyle Lagoon is not natural. It was formed after an accumulation of gravel from a
hillside excavation became deposited, together with sand and debris, on the seaward side of a
small inlet of North Bay. At high tide, water may enter the lagoon through its narrow connec-
tion with the inlet. At low tide, some water drains out of the lagoon. However, the water level
in the lagoon does not vary a great deal, and most of the time it is higher than that of North Bay
and the inlet.
NEW ACOELS FROM THE PACIFIC COAST 155
appear nearly black ; under higher magnification, they appear brown. However,
the individual bodies in the aggregates are nearly colorless.
The body is entirely covered by cilia about 10 p. long. Scattered over the body
surface there are stiff, cilia-like bristles (Fig. 4) up to about 24 ^ long. These
are probably sensory in function. The bundles of epicytial rhabdites (Fig. 2)
are rather evenly distributed on both the dorsal and the ventral surfaces. They
fall into poorly-defined short rows (Fig. 4).
The mouth is located on the ventral surface, slightly anterior to the middle of
the body. The pore is kept closed most of the time, but its position may be estab-
lished by finding a characteristic convergence of rows of cilia. The mouth is
capable of great distention during ingestion of food and during elimination of
undigested material, such as diatom frustules.
The principal elements of the nervous system in this small acoel are not clear
in any of my preparations. Close to the anterior end of the body, in front of the
statocyst, a ring-like concentration of nerve tissue encircles the so-called ''frontal
organ" (the confluence of ducts of the frontal glands approaching the pore through
which their secretion is discharged). However, the nerve tissue and ectocytium
are so closely bound together that I have not established how many ganglia con-
tribute to the brain mass, and I have not been able to trace any important nerves
Much of the anterior quarter of the body is occupied by the frontal glands
and their secretion (Figs. 6, 7). In sections, the secretion is conspicuous as a
pale yellowish material which is not appreciably stained by either hematoxylin
or acid counterstains such as eosin, orange G, and fast green. The pore through
which the secretion is discharged is circular and is located at the anterior tip of
the body. The epicytium is supplied with numerous small glands (Fig. 8) within
which the bundles of rhabdites are formed. The rhabdites are destroyed by the two
fixatives which I used.
The subepicytial musculature (Fig. 8) consists of an outer layer of circular
muscles and an inner layer of longitudinal muscles. In the parenchyma, there are
scattered longitudinal and dorsoventral muscle fibers ; dorsoventral muscles travers-
ing the endocytium near the mouth are particularly conspicuous (Figs. 6, 7). The
musculature associated with the copulatory organs will be described subsequently.
In the region of the mouth, the endocytium, into which food is ingested,
occupies most of the body mass mesial to the ovaries and testes (Fig. 7). The
endocytium extends anteriorly as far as the frontal gland cells and posteriorly
as far as the anterior edge of the seminal vesicle. The ectocytial layer, which
is very thin at the level of the mouth, becomes slightly more prominent anteriorly,
and is very conspicuous in the posterior quarter of the body. Dorsal, lateral, and
posterior to the copulatory organs, the vacuoles in the ectocytium reach a very
large size (Figs. 1, 5, 6, 7).
The testis and ovary on each side of the body are closely apposed for most of
their length. In the region just behind the frontal glands, the testes are lateral
and dorsal to the string of small oogonia lying near the ventral epicytium (Figs.
6, 7). As the oogonia enlarge into oocytes, and therefore occupy progressively
more of the body mass as they migrate posteriorly (Fig. 9), the testes become
gradually restricted to a narrow zone lateral to the oocytes.
From the posterior end of each testis, a delicate duct carries sperm through
156 EUGENE N. KOZLOFF
the parenchyma to the seminal vesicle ( Figs. 5, 10). The two sperm ducts enter
the seminal vesicle at rather widely separated points on its anterolateral surfaces.
The seminal vesicle (Figs. 5. <>, 7, 11 ) lias a thin muscular wall, and in mature
specimens invariably contains inactive sperm. Within the seminal vesicle, on its
posteroventral side, there is a cluster of granule-filled masses which surround a
small cavity continuous with the lumen of the penis. In life, the cluster resembles
a group of cells (Fig. 5). but the boundaries of the individual masses are de-
stroyed by fixation, and I have not been able to distinguish nuclei among the
granules, which are refractile and are stained by hematoxylin. The penis appears
to be of a type which is everted during copulation, and presumably when this
takes place at least some of the granules at its tip are discharged.
The mature sperm (Fig. 3) of P. luteola are about 150 p. long. Behind the
appreciably thickened anterior portion (slightly over one-third of the total length),
the tail of the sperm narrows gradually to a very fine tip.
The vagina, supplied externally with an outer layer of longitudinal muscles
and an inner layer of circular muscles, extends at first almost directly dorsally
away from the genital atrium. This lower portion of the vagina has a distinct
lumen (Figs. 6, 7) ; the lumen becomes gradually more extensive, and crescentic
in outline as it is viewed from the dorsal side in living specimens (Fig. 5). The
surface of the syncytial wall of the vagina next to the lumen is covered with small
granules which appear to be of the same type as those associated with the tip of
the penis. Some of these granules are noted within the tissue of the vagina and
also within the lumen.
As the vagina arches anterodorsally over the seminal vesicle, the lumen
becomes obliterated by a syncytial mass continuous with the syncytium of the rest
of the vagina, and the layer of circular muscles becomes more pronounced. In
life, the syncytium contains refractile crystal-like granules (Fig. 5) ; in specimens
which have been fixed and sectioned, the granules are not preserved, and the
syncytium is conspicuously vacuolated (Figs. 7, 11). Finally, the musculature
disappears, and the vagina passes insensibly into a syncytium distinct from the
digestive endocytium and within which the seminal bursa develops (Figs. 5, 7, 10).
In some living specimens, as well as in sectioned preparations, sperm are observed
in two or more spaces which may be connected or apparently separate (Fig. 7).
Extending ventrally or posteroventrally from the bursa is a heavily cuticularized
nozzle invested by what appears to be a fibrous tissue (Figs. 7, 10). The sperm
in the seminal bursa usually exhibit considerable activity.
How the sperm reach the syncytium, within which the rather poorly-defined
seminal bursa develops, is not clear. I have not been able to distinguish a continu-
ous clear passage through the syncytium constituting that portion of the vagina
which lies above the seminal receptacle. However, sperm have been noted in the
lower portion of the vagina. It is possible that when insemination is effected,
the sperm entering the vagina are simply forced through the syncytium to the region
where the bursa is formed.
In the parenchyma around the seminal vesicle and anterior region of the vagina,
there are a number of cellular elements which appear to be gland cells. The
exact distribution of these glands and the pathways by which their secretion or
secretions are delivered to other organs have not been worked out.
NEW ACOELS FROM THE PACIFIC COAST 157
The holotype specimen, in the form of a set of serial sagittal sections, has been
deposited in the United States National Museum (USNM No. 32902).
The nature of the brain of P. lutcola, and the fact that its vagina enters the
genital atrium behind the copulatory complex, indicate that it belongs in the family
Otocelididae. Westblad (1948) established this family to include a single genus,
Otocelis, which had previously been referred to the Convolutidae by most students
concerned with this general group of acoels.
Westblad (1946) recognized only two species of Otocelis: 0. rubropunctata
(Schmidt) and 0. giilhuarcnsis Westblad. Ax (1959) pointed out that the acoel
believed by Westblad to be 0. rubropunctata is quite distinct from the worm de-
scribed by Schmidt and later studied in detail by von Graff. The true 0. rubropunc-
tata, which has a single genital pore, is not definitely known to occur outside the
Mediterranean Sea and Black Sea. Westblad's 0. "rubropunctata," from Scandi-
navian localities, has separate male and female pores. Ax proposed that it be
Two other acoels have rather recently been added to the genus Octocelis.
0. dichona Marcus (1954) is distinctive in having the genital pore located at
the posterior end of the body. 0. sachalinensis Ivanov (1952) is probably more
nearly similar to 0. rubropunctata than to any other species of Otocelis. How-
ever, it lacks eyes, and the organization of the penis is very much like that in
P. lutcola. Certain of Ivanov's figures suggest that the tip of the penis of 0.
sachalinensis has masses of granules similar to those associated with the penis of
P. lutcola, although Ivanov did not mention any such masses in the text.
In the acoel I have described, the most distinctive feature, not shared by any
of the other known species of Otocelis, is the peculiar nature of the anterior part of
the vagina, where the lumen appears to be obliterated. It is primarily on the
basis of this characteristic of P. luteola that I propose a new genus. I am fully
aware that 0. sachalinensis and P. luteola are similar in a number of respects, but
the relationship of P. luteola to the genotype (O. rubropunctata} or to the other
species of Otocelis is probably considerably more remote.
Raphido phallus actuosus gen. nov., sp. nov.
This acoel is moderately common in the small inlet of North Bay with which
Argyle Lagoon communicates. Washings of Ulva detached from substrates of
muddy sand or gravel at tide levels ranging from about --1 to +4 ft. often contain
some R. actuosus.
When extended and gliding actively on a firm substrate (Fig. 12), the length
of R. actuosus is equal to about four times the width. Anteriorly, the body is
rounded ; posteriorly, it tapers only slightly. The largest specimens, in a normal
state of extension, are about SSO ^ long and 220 /j. wide. When the worms are
in tight contact with the substrate, the ventral surface is flattened, but the thickness
in the mid-dorsal region may nearly equal the width. When swimming free of
the substrate, R. actuosus becomes almost cylindrical.
Of the three acoels described in this paper, R. actuosus is the most active, and
it is also the most fragile. When the animal is swimming in contact with the
substrate, its movements are jerky, and the posterior part of the body is often
twitched back and forth, as if it were being irritated. Addition of a very little
158 EUGENE X. KOZLOFF
isotonic magnesium chloride may cause it to disintegrate, and when it is under
slight pressure from a coverglass it is less likely to maintain its integrity than the
other two species.
The statocyst is located near the end of the first one-eighth of the body. In
larger specimens, its diameter is about 20 /*. The diameter of the statolith is
about 14 p.. The shape of this structure is approximately hemispherical, and
the convex surface is uppermost.
Viewed with reflected light, the body (except for the digestive endocytium)
is whitish. The endocytium is typically brownish yellow, but it may be greenish
yellow, or partly of this color. Deposits of bright white material are usually
very conspicuous in the dorsal part of the body around the statocyst, and in a
broken streak extending for most of the length of the body along the midline.
In strong transmitted light, the diatoms taken into the digestive endocytium
are observed to change from a yellow-brown or olive color to greenish yellow and
brownish yellow. The pigments diffuse out of the frustules and color the
endocytium as a whole. Small lipid droplets are abundant in the ectocytial
parenchyma, especially in the anterior half of the body. Most of these are yellow
in color, and occur in clusters of various shapes ; some clusters contain a large
number of droplets, and are confluent with other clusters. The bright white
deposits noted around the statocyst and along the midline when the worms are
studied in reflected light are aggregates of small refractile granules which indi-
vidually are pale yellowish green in color. The aggregates, however, appear
blackish or brownish. They lie within the ectocytial parenchyma in the dorsal
part of the body.
The body is entirely covered by cilia about 8 or 9 p. long. Scattered over the
body surface are stiff, cilia-like bristles. Most of these are approximately 15 p.
long, but in the caudal region some of the bristles may reach a length of nearly
30 p.
The bundles of rhabdites of R. actnosiis are conspicuous because they are
closely spaced and are arranged in definite rows (Fig. 13). A particular row
of rhabdites is never very long, however, and eventually merges with another
row or terminates as two other rows converge.
The mouth is located on the ventral surface just posterior to the middle of the
body. It is capable of rapid distention during the ingestion of food and elimination
of undigestible residues (largely diatom frustules).
The brain appears to consist of four major ganglia, one anterolateral and one
posterolateral to the statocyst on either side. Heavy commissures connect the
ganglia in front of and behind the statocyst, so that the latter is almost completely
enclosed within nerve tissue. My preparations do not clearly show the nerve
trunks which originate from these ganglia.
The frontal glands and their accumulated secretion occupy a considerable part
of the body mass in the vicinity of the statocyst (Fig. 17). The secretion appears
in sectioned specimens as a pale yellowish material. The circular pore through
which the secretion is discharged is located at the anterior end of the body, but
is directed slightly downward. The epicytium is supplied with many small glands
(Fig. 18) within which the bundles of rhabdites are formed.
The subepicytial musculature (Fig. 18) consists of an outer layer of circular
muscles and an inner layer of longitudinal muscles. Parenchyma! muscles are also
NEW ACOELS FROM THE PACIFIC COAST 159
present ; these are most conspicuous in the anterior part of the body, in the region
occupied by the frontal glands.
The digestive endocytitim reaches anteriorly to the frontal glands and pos-
teriorly nearly to the back edge of the seminal vesicle (Fig. 17). The ectocytial
layer is rather thin in most regions of the body. It becomes appreciably thicker
near the anterior end, but is most extensively developed in the posterior part of
the body, where vacuoles within it are conspicuous lateral, dorsal, and posterior
to the copulatory organs (Figs. 12, 15. 16, 17).
The testes and ovaries are approximately one-half the length of the body,
and anteriorly they reach nearly to the level of the statocyst. In front of the
mouth, the testes form a considerable part of the body mass. They are located
above the string of enlarging oogonia, and their distribution is lateral and dorsal
to the endocytium (Figs. 19, 20). For about one-half of their length, the testes
of the right and left sides are confluent dorsally. However, as the endocytium
becomes limited to the dorsal part of the body and the oocytes beneath it become
very large, the testes become distinctly separate, and finally they occupy only a
very small portion of the body mass as seen in transverse sections.
The genital pore (Figs. 15, 17) is located on the ventral surface near the
beginning of the last quarter of the body. In living specimens, the genital atrium
contains a number of more or less ovoid masses of granular material (Fig. 15).
The source of these is not known. In sections of fixed specimens, the secretion
within the genital atrium has the appearance of a vacuolated coagulum (Fig. 17) ;
small granules which are stained by iron hematoxylin are scattered through this.
The seminal vesicle (Figs. 15, 16, 17, 21) is located posterodorsal to the
genital atrium. The sperm ducts leading from the testes enter it at rather widely
separated points on its anterolateral surface. The wall of the seminal vesicle is
thin but muscular. The penis, as seen in sagittal sections (Fig. 17), arches from
the genital atrium through the upper part of the seminal vesicle, and its lumen
communicates with the cavity of the seminal vesicle at the rear. The penis is
invested externally by an outer layer of longitudinal muscles and an inner layer of
circular muscles, and its lumen is provided with a number of separate and very
delicate cuticular rods. Presumably, the penis is everted during copulation. The
cavity of the seminal vesicle is filled with inactive sperm. It is crescentic in out-
line when viewed from above, but it extends farther anteriorly near the ventral
side of the seminal vesicle than near the dorsal side. Between the sperm mass and
the penis there is a large accumulation of granules which are conspicuous in living
specimens (Fig. 15) and which are stained strongly by hematoxylin (Figs. 16,
17, 21).
The mature sperm (Fig. 14) are about 110 \> long, and their structure is very
interesting. Behind the thickened anterior region, a number of delicate cilia-like
projections extend away from the sperm. The basal portions of these projections
are appreciably thicker than the slightly longer outer portions. The posterior
region of the sperm narrows gradually to a very fine tip.
The vagina (Fig. 17) extends anterodorsally from the genital atrium. It
is short, and a part of it is ciliated. Where the lumen terminates, there are glands
which produce the elongate clusters of granules often noted anterior to the genital
pore in living specimens (Fig. 15). When worms of this species are compressed,
the clusters of granules may actually protrude from the genital pore. In sectioned
160
EUGENE X. KOZLOFF
.-
21
J'late II Raf>liidopha!lus actuosns
All figures were prepared with the aid of a camera lucida, but in the case of specimens
drawn from life (Figs. 12-15), most details were sketched in free-hand. Figures 16-21 are
based on sections (6 /*) of specimens fixed in Bouin's fluid and stained with iron hematoxylin
NEW ACOELS FROM THE PACIFIC COAST 161
preparations, only traces of the clusters can be detected in the anteriormost part
of the wall of the vagina, and a brownish-yellow coagulum is noted in the lumen
of the vagina near them. Between the glandular cap of the vagina and the seminal
bursa, there is a syncytial mass within which the nuclei are rather close together,
and through which sperm are probably forced into the bursa at the time of
insemination.
The holotype specimen, in the form of a set of serial frontal sections, has been
deposited in the United States National Museum (USNM No. 32903). It was
collected in the small inlet of North Bay which communicates with Argyle Lagoon,
San Juan Island, Washington.
This acoel can be referred to the family Convolutidae, and may be rather closely
related to certain of the diverse species of Convoluta. The penis lies within the
seminal vesicle in much the same manner as that of C. divae Marcus (1950), C.
the presence of numerous cuticularized rods within the penis is distinctive. I base
the genus Raphidophallus largely on this combination of characters.
Diatoinoi'ora amoena gen. nov., sp. nov.
This relatively large species is usually found in washings of Ulva growing on
muddy sand or gravel in the small inlet of North Bay which communicates with
Argyle Lagoon. Samples collected at tide levels ranging from 1 to +4 ft. generally
contain D. anioena; as a rule, it is more abundant than R. actnosus. I have also
found it in washings of Ulva and Enteromorpha taken from muddy sand in South
Slough at Charleston, Oregon (Lat. 43 20.4' N. ; Long. 124 19.5' W.) at tide
levels of about +2 to +5 ft.
When extended and gliding in contact with a firm substrate (Fig. 22), the body
is about four times as long as wide. The largest specimens are about 1200 p, by
300 fj,. The body is rounded anteriorly and tapers slightly toward the posterior end.
Although the body is usually widest near the middle, the width remains almost
constant in the second and third quarters. The greatest thickness, just behind the
middle of the body, is nearly equal to the width. When the worms are gliding on a
firm substrate, the ventral surface is flattened ; when swimming free, the body
becomes nearly cylindrical.
(some preparations were counter stained with orange G) ; certain details were supplied from
adjacent sections in the same series. For abbreviations, see legend for Figures 1-11.
FIGURE 12. Specimen in contact with substrate ; dorsal view.
FIGURE 13. Rhabdites near left margin of body at the level of the statocyst.
FIGURE 14. Mature sperm.
FIGURE 15. Posterior end (specimen slightly compressed under a coverglass) ; ventral view.
The masses of granular material shown next to the genital pore lie within the genital atrium.
FIGURE 16. Frontal section. In the anterior part of the body, the section shows the region
slightly ventral to the level of the statocyst and pore of the frontal glands ; one of the oocytes is
undergoing a maturation division.
FIGURE 17. Median sagittal section.
FIGURE 18. Epicytium, epicytial glands, subepicytial musculature, and portion of testis in
transverse section just anterior to mouth.
FIGURE 19. Transverse section just anterior to mouth.
FIGURE 20. Transverse section through nozzle of seminal bursa of same specimen.
FIGURE 21. Transverse section through seminal vesicle and penis of same specimen.
162
EUGENE N. KOZLOFF
* ' ' N
g ' '
'^ . *> - : ' >
:/ ?.;
-<
; a
r -
, i >*" i
;
r l -- : ...-,
g .^ J
!v . 1 : '-' ':' "."'..' ;
.
^^
27
I'lute III- Diatomovora unwcna
All figures were prejiared with the aid of i camera lucida, but in the case of specimens
drawn from life (Figs. 22, 23, 26), most details were sketched in free-hand. Figures 24, 25,
NEW ACOELS FROM THE PACIFIC COAST 163
The statocyst lies near the end of the first one-tenth of the body. In larger
individuals, its diameter is about 25 /JL. The diameter of the hemispherical statolith
As viewed with reflected light, the body (excluding the digestive endocytium) is
whitish, tinged with yellow; the yellow color, concentrated in lipid droplets, is
prominent in the anterior quarter, and sometimes also near the posterior end. Near
the dorsal surface, there are generally three discontinuous streaks of bright white
material ; these streaks originate behind the statocyst and diverge as they extend
posteriorly. Some specimens have only one conspicuous streak along the midline ;
in others, the lateral streaks are distinct and the median streak is diffuse. The
digestive endocytium is usually green, although sometimes it is greenish yellow.
In strong transmitted light, the ingested diatoms within the endocytium may be
observed to turn from yellowish brown or yellowish green to a bluish green color.
The endocytium as a whole is usually pale bluish green. Lipid droplets up to about
15 ju. in diameter are scattered through the parenchyma, especially in the anterior
quarter of the body. Some of these are quite yellow, and contribute to the yellowish
cast noted in specimens examined in reflected light. The discontinuous streaks
which appear white in reflected light are composed of greenish refractile granules
(the larger of which are sculptured disks reaching a diameter of about 7 ju.) con-
centrated in the ectocytium dorsal and dorsolateral to the endocytium. Under low
magnification, the aggregates of these granules may appear blackish or brownish.
The body is covered by cilia about 10 /* long. The bundles of rhabdites resemble
those of R. actuosus; they are closely spaced and are arranged in rather definite
rows. Most of the rows are short and merge with other rows or simply terminate
as the neighboring rows on either side converge toward one another.
The mouth is located on the ventral surface, just anterior to the middle of the
body. It is capable of being considerably distended during the ingestion of food,
which consists largely of diatoms and eggs of copepods, and during elimination of
diatom frustules and other indigestible residues.
The nervous system has not been studied in detail. The brain appears to
consist of four major ganglia and their commissures. There are two ganglia on
either side of the statocyst one anterolateral and the other posterolateral. These
27-30 are based on sections (6 /a) of specimens fixed in Bouin's fluid and stained with iron
hematoxylin and orange G (or eosin) ; in most cases, some details have been supplied from
adjacent sections in the same series. For abbreviations, see legend for Figures 1-11.
FIGURE 22. Mature specimen (slightly compressed under a coverglass) ; dorsal view.
FIGURE 23. Posterior end (specimen slightly compressed under a coverglass) ; ventral
view. The globules on the topographic right side of the penis are within the lumen of the vagina.
FIGURE 24. Frontal section. Most details have been omitted, and the position of the vagina
and seminal bursa, which lie some distance below the level of the structures traced, are
rendered diagrammatically.
FIGURE 25. Median sagittal section. The vagina and seminal bursa were drawn from a
number of sections considerably to the left of the section traced.
FIGURE 26. Mature sperm.
FIGURE 27. Epicytium, epicytial glands, subepicytial musculature, and portion of testis in
transverse section just anterior to mouth.
FIGURE 28. Transverse section just anterior to mouth.
FIGURE 29. Transverse section through anterior nozzle of seminal bursa of same specimen.
FIGURE 30. Transverse section through region of genital pore and genital atrium of same
specimen.
164 EUGENE N. KOZLOFF
are fused almost completely, and communicate with their counterparts on the other
side by thick commissures.
The frontal glands and their secretion (Figs. 24, 25) occupy much of the
anterior fifth of the body. The pore through which the secretion is discharged is
located at the anterior end of the body and is directed slightly downward. The
glands within which the bundles of rhabdites are formed may be recognized within
the epicytium (Fig. 27).
The subepicytial musculature (Fig. 27) consists of an outer layer of circular
muscles and an inner layer of longitudinal muscles. Parenchymal muscles are also
present. These are rather abundant in the region of the frontal glands (Fig. 25)
and in the region of the copulatory organs (Fig. 30). However, parenchymal
muscles having a nearly dorsoventral orientation are also prominent lateral to
the endocytium near the mouth (Fig. 28).
In the region of the mouth, much of the body mass mesial to the testes and
ovaries is occupied by the endocytial parenchyma into which food is ingested.
The endocytium extends forward to the frontal glands (Fig. 25). Posteriorly
it reaches beyond the anterior margin of the seminal vesicle, although it gradually
becomes restricted to the dorsal part of the body mass, above the enlarging oocytes,
seminal bursa, and seminal vesicle. The ectocytial parenchyma is rather thin where
the endocytium is most extensive. It becomes appreciably better developed near
the anterior end, and is very prominent in the posterior part of the body. Dorsal,
lateral, and posterior to the copulatory organs, the ectocytium is characterized by
large vacuoles (Figs. 22, 23, 24, 25, 30).
The testes are distinctly separate. In the region just behind the frontal glands,
the testis on either side of the endocytium occupies nearly a third of the body
mass. Farther posteriorly, however, the oogonia which are ventral to each testis
become progressively larger, and the testes become gradually more restricted
(Figs. 28, 29).
The genital pore (Figs. 23, 25, 30) is located on the ventral surface near the
beginning of the last one-sixth of the body. The genital atrium has a ciliated
epithelium and is externally lightly muscularized. The penis has a heavy external
musculature consisting of an outer layer of longitudinal fibers and an inner layer
of circular fibers. Its lumen is filled with globules which consist of small granules.
In some preparations, these granules are stained distinctly by hematoxylin ; as
a rule, however, hematoxylin seems to be removed from them by routine deslaining,
and they become readily colored by eosin and orange G.
The penis leaves the left side of the genital atrium and follows a nearly circular
ascending path through the seminal vesicle. The cavity of the seminal vesicle is
filled with inactive sperm and globules of the type observed within the lumen of
the penis. The delicate sperm ducts passing posteromedially from the testes enter
the seminal vesicle on its dorsolateral surfaces.
The mature sperm (Fig. 26) are approximately 250 ^ long. From the thick-
ened anterior portion, the body becomes gradually narrowed to a very fine tip. A
conspicuous undulating membrane spirals around the anterior two-thirds of the
sperm. Undulations of the more slender posterior region appear to be continuous
with those of the undulating membrane, and perhaps the latter extends almost the
entire length of the sperm.
NEW ACOELS FROM THE PACIFIC COAST 165
The vagina (Figs. 24, 25) has a thick tunic of circular muscles, and leaves
the genital atrium ventral to the seminal vesicle. It is directed at first slightly to
the right, then bends toward the midline on its course to the seminal bursa. For
most of the length of the vagina, the lumen is distinct, and this may contain a
number of globules of the type noted within the seminal vesicle and penis. Just
before the vagina reaches the bursa, the lumen is obliterated by a syncytial mass con-
tinuous with the syncytial wall of the vagina. In life, this mass often contains
clusters of refractile granules, and is very similar to that which obliterates the
lumen of the anterior part of the vagina in P. luteola. In fixed and sectioned
specimens, it is vacuolated and the granules are not preserved. The seminal bursa
is invested by a heavy coat of fibrous elements ; external to this, there are some
widely-spaced muscles.
The bursa has two cuticularized nozzles (Fig. 25) ; one of these is directed
almost anteriorly, and the other is usually directed dorsally or anterodorsally. The
bursa generally contains active sperm, but in some specimens it is filled with the
granule-bearing syncytium which usually characterizes the anterior portion of the
vagina. It appears likely that unless the bursa is distended by sperm forced into
it at the time of insemination, it tends to collapse and thus appears to envelop the
syncytial mass just behind it.
Gland cells are extensively developed in the parenchyma around the copulatory
organs, but I have not worked out the pathways by which the secretion or secretions
of these glands are delivered to other structures.
The holotype specimen, in the form of a set of serial sagittal sections, has been
deposited in the United States National Museum (USNM No. 32904). It was
collected in the inlet of North Bay which communicates with Argyle Lagoon, San
Juan Island, Washington.
Like the preceding species, this acoel belongs in the Convolutidae. Its long and
highly muscular penis is somewhat similar to that of Aphanostoma macrospirijeriiiii
neither of these species has a seminal bursa. When a bursa is present in members
of the genus Aphanostoma, it does not have a cuticularized nozzle, although West-
blad has questioned the importance of this characteristic in setting Aphanostoma
apart from Convolnta. The heavily mtiscularized vagina of D. amoena and the
nature of its seminal bursa, which has two nozzles and a thick wall consisting of
fibrous elements surrounded by muscles, are characteristics which have persuaded
me to propose a new genus.
SUMMARY
Acoels belonging to three new genera are described. Parotocelis luteola is
referred to the family Otocelididae. Raphido phallus actuosus and Diatomovora
amoena are placed in the family Convolutidae. All of these acoels have been
collected intertidally on San Juan Island, Washington, on substrates of muddy sand
and gravel supporting growths of Ulva and Enteromorpha. D. amoena has also
been found at Charleston, Coos County, Oregon.
LITERATURE CITED
Ax, P., 1959. Zur Systematik, Okologie und Tiergeographie der Turbellarienfauna in den
ponto-kaspischen Brackwassermeeren. Zoo/. Jahrb., Abt. f. System., Okol. Geogr.
Tiers, 87: 43-184.
166 EUGEXK X. KOZL01-T
, H. M., AND D. P. CosTF.i.i.o, 1 ( '38. A n f\v species of i'olycliacnts from the Pacific
coast. . Inn. .M,i</. Nat. Hist., ser. 11,1: 148-155.
HVMAN, L., 1 ( '5 ( ). Some Turbellaria from the coast of California. Aincr. Mits. Xnrit., No.
1943.
IVANOV, A., 1952. Beskishechnye turbelliarii (Acoela) iuzhnogo poberezh'ia Sakhalina. Trudy
Zoologicheskogo Instituta Akadcmii Nauk SSSR, 12: 40-132.
MARCUS, E., 1950. Turbellaria Brasileiros (8). Bol. Fac. Fil., Cicnc. Lcir. Unir. Sao Paula ,
Zoologia, No. 15: 5-191.
.\[ARCUS, E., 1954. Turbellaria Brasileiros XI. Papcis Antlsos Depart. Zool., Sccr. Ayric.,
Sao Paulo, 11: 419-489.
WKSTBLAD, E., 1946. Studien iiber Skandinavische Turbellaria Acoela. IV. Arkir f. Zooloqi,
38A, No. 1.
\\'KSTHI.AI), E., 1948. Studien iiber Skandinavische Turbellaria Acoela. V. Arklv f. Zoologi,
41 A, No. 7.
THE SEPARATION OF POST-BASICORONAL AREAS FROM THE
BASICORONAL PLATES IN THE INTERAMBULACRA OF THE
SAND DOLLAR, ECHINARACHNIUS PARMA (LAMARCK) 1
PRASERT LOHAVANIJAYA a AND EMERY F. SWAN
Department of Zoology, University of Neiv Hampshire, Durham, New Hampshire 03824
One possible arrangement of the coronal plates of the central portion of the oral
surface of the test of the sand dollar Echinarachnius parma (Lamarck) is shown
as Figure 1. In this specimen the post-basicoronal interambulacral areas one
through four are in contact with the basicoronal plates, but in interambulacrum five
the post-basicoronal area has become separated from its basicoronal plate. Durham
(1955) has indicated that the geologically younger genera of scutellinid echinoids
tend to have the interambulacral columns separated from the basicoronal plates,
whereas in the older genera these columns and plates are in contact. He also
noted that in the Pacific Coast sand dollar, Dcndraster excentricus (Eschscholtz),
a member of one of the younger or more advanced genera, very small or young
individuals had their basicoronal interambulacral plates in full contact with the
succeeding plates and that as growth proceeds, the second plate of each ambulacral
column grows faster than the others and eventually separates the second inter-
ambulacral plate from contact with the basicoronal interambulacral plate. Of all the
species he studied for variation, Eclrinarachnius parma was found to be the most
variable in respect to the separation of the interambulacral columns from the
basicoronal plates. This study has been made with the aim of determining
whether any pattern can be noted in this variation. With this in mind three
questions are posed :
1. How many areas lose contact, and to what extent does this vary among speci-
mens within and between collections from different localities?
2. Is there indication that there is any usual sequence among the areas in their
loss of contact, and does this vary within and between collections from different
localities ?
3. Within areas retaining contact, are there differences in the amount of contact
between first post-basicoronal plates "a" and "b" with the basicoronal plates?
Is there any regular pattern of distribution of this asymmetry among the areas, and
does this vary within and between collections from different localities ?
MATERIALS AND METHODS
Four series of specimens were collected intertidally, one series from each of
the following places : Crow Neck, North Trescott, Washington County, Maine
(44 52' 37" N., 67 07' 38" W.) ; Bailey's Mistake, South Lubec, Washington
1 The greater part of this work was included in a dissertation submitted by the senior
author to the University of New Hampshire in partial fulfillment of the requirements for the
Ph.D. degree.
- Present address : New England College, Henniker, New Hampshire.
167
168
PRASERT LOHAVANIJAYA AND EMERY F. SWAN
County. Maine (44 46' 23" N., 67 03' 16" W.) ; Hampton Beach, Rockingham
County, New Hampshire (42 54' 07" N., 70 48' 40" W.) ; and Hampton Harbor,
Rockingham County, New Hampshire (42 53' 59" N., 70 49' 07" W.). To
minimize the possibility of the introduction of variability resulting from possible
seasonal differences these collections were all made within as short a time period
as feasible (September 12-15, 1962). Pertinent environmental characteristics of
these collecting localities have been discussed by Lohavanijaya (1965).
a
a
FIGURE 1. Oral surface of central portion of test of Echinarachnius par ma, showing contact
or lack of contact between basicoronal interambulacral plates and first post-basicoronal plates.
Stippled areas are interambulacral and white areas are ambulacral.
More careful examination of the specimen shown in Figure 1 reveals not only
that the post-basicoronal interambulacral areas 1, 2, 3, and 4 are in contact with
their basicoronal plates, but also that the nature of this contact varies. In area 1
the first post-basicoronal plate "a" is in contact but "b" has lost contact, whereas
in area 4 the situation is reversed. In areas 2 and 3 both "a" and "b" remain in
contact, but it looks as though "b" were approaching loss of contact in area 3 while
in area 2 the degree of contact appears more nearly equal.
In order to tabulate such variants for the large numbers of specimens studied,
the following system of symbols has been devised.
If both plates "a" and "b" of the first post-basicoronal interanilmlacrals are "in contact"
with the basicoronal to an approximately equal degree, the condition is designated : + +
If botli plates "a" and "b" are "in contact" but "a" is to a greater degree, the condition
is designated : + ~
VARIATION IN SAND DOLLARS. II.
169
If both plates "a" and "b" are "in contact" but "b" is to a greater degree, the condition
is designated : \-
If only plate "a" is "in contact," the condition is designated : + Q
If only plate "b" is "in contact," the condition is designated : O +
If both plates "a" and "b" are "out of contact," the condition is designated : O O
Such data were compiled for the five interambulacral areas for a total of 1280
specimens. There were a few specimens for which these relationships could not
TABLE I
The nature of contact between first post-basicoronal interambulacral plates and basicoronal plates for
the five areas of the oral surface of the test for series of specimens from four localities.
N = the total numbers of specimens in each series. The numbers in the bulk of the
table represent the numbers of specimens having each possible type of contact
or absence of it (00) for each interambulacral area
Area
a b
+ +
a b
H
a b
+
a b
a b
+
a b
- +
N
BM* 1
2
56
72
161
1
1
293
2
32
19
5
85
36
116
3
52
94
26
89
11
21
4
2
116
98
77
5
7
2
2
210
14
58
CN* 1
8
73
106
105
2
1
295
2
30
17
5
68
79
96
3
61
71
39
53
19
52
4
2
3
1
88
109
92
5
8
225
28
34
HH* 1
11
149
76
68
7
311
2
50
67
7
60
22
105
3
72
115
21
46
2
55
4
7
3
65
70
166
5
34
10
2
89
41
135
HB* 1
39
171
68
44
37
11
370
2
122
58
6
31
19
134
3
151
89
10
11
15
94
4
39
18
1
58
56
198
5
88
9
62
57
154
BM Bailey's Mistake; CN Crow Neck; HH Hampton Harbor; HB Hampton Beach.
be determined, a few that were malformed, injured, or otherwise so abnormal that
they were not considered typical, and a very few so far from the usual sizes within
each series that they were considered unusual. The specimens (23) in these cate-
gories have not been included in this study. The spines and the superficial organic
material on the oral surface of the test were brushed off thoroughly. Then, in
order to make the sutures separating the plates more readily visible, water was
applied to the test. For determination of the nature of the contact between the
basicoronal plates and the post-basicoronal areas, examination of the specimens
170
PRASKRT LOHAVANITAYA AND EMERY F. SWAN
TAIU.K H
Comparison of frequency of occurrence of specimens with the "normal," "1st order" and "2nd order"
deviant arrangements of interanibulacral areas "out of contact" for specimens with 0, 1, 2, 3,
4 or all areas "out of contact" for Echinarachnius parma from the four localities studied
Series
* of
specimens
' , t
collection
# of
areas "out
of contact"
Normal sequence
Deviant sequences
#
%*
1st order**
2nd order**
#
%
$% CN (15-70 mm.) 74 <M 36 24.7 31.1 12.0 1 2 74 91 18 100.0 97.8 50.0 Not p 2 18 issible 2.2 50.0 Not possible Not possible 0.0 41 13.7 3 20 48.8 15 36.6 6 14.6 34 11.4 4 13 38.2 15 44.1 6 17.6 21 7.0 all 21 100.0 Not possible Not possible Average number of areas "out of contact" per specimen = 529/299 = 1.77 BM (50-90 mm.) 68 48 45 22.4 15.8 14.9 1 2 68 39 29 100.0 81.3 64.4 Not p 9 14 assible 18.8 31.1 Not possible Not possible 2 4.4 58 19.1 3 29 50.0 19 32.8 10 17.2 40 13.2 4 18 45.0 15 37.5 7 17.5 44 14.5 all 44 100.0 Not possible Not possible Average number of areas "out of contact" per specimen = 692/303 = 2.28 HB (20-59 mm.) 241 56 21 65.1 15.1 5.7 1 2 241 33 9 100.0 58.9 42.9 Not p 23 4 assible 41.1 19.0 Not possible Not possible 8 38.1 26 7.0 3 19 73.1 4 15.4 3 11.5 14 3.8 4 11 78.6 3 21.4 0.0 12 3.2 all 12 100.0 Not possible Not possible Average number of areas "out of contact" per specimen = 292/370 = 0.79 HH 182 58.7 182 100.0 Not possible Not possible (40-65 mm.) 44 14.2 1 24 54.5 20 45.5 Not possible 26 8.4 2 2 7.7 12 46.2 12 46.2 18 5.8 3 8 44.4 2 11.1 8 44.4 22 7.1 4 11 50.0 4 18.2 7 31.8 18 5.8 111 18 100.0 Not possible Not possible . Average number of areas "out of contact" per specimen = 328/310 = 1.06 " These percentages refer to the percentage of specimens with the indicated number of areas "out of contact" having the sequence indicated. ** First order deviants are those presumed to be normal except for last one out of contact. Second order deviants are those combinations in which there appears to be aberrance in sequence in loss of contact prior to the last area involved. VARIATION IN SAND DOLLARS. II. 171 with a hand lens was necessary. Each series of specimens was divided into size groups at 5-mm. intervals (except where numbers were inadequate). The data thus obtained were tabulated. In Table I these data are summarized by locality and area of test but without breakdown into size groups. TABLE III Distribution of numbers of interambiilacral areas "out of contact" among different size groups of Echinarachnius parma from four localities Series Mean diameter J (L + W) No. of specimens Number of areas "out of contact" Mean i 2 3 4 5 CN 15-23.9 10 8 1 1 , 0.30 27-34.9 7 4 1 1 1 . 0.86 35-39.9 15 5 4 2 3 1 1.47 40-44.9 38 11 12 2 5 6 2 1.71 45-49.9 42 8 10 6 10 5 3 2.07 50-54.9 63 12 22 11 7 8 3 1.78 55-59.9 67 11 24 10 7 10 5 1.94 60-64.9 38 11 13 2 5 4 4 1.76 65-69.9 19 4 7 1 3 1 3 1.95 BM 50-54.9 30 7 9 3 4 6 1 1.87 55-59.9 66 17 9 14 7 11 8 2.15 60-64.9 59 21 8 4 13 5 8 1.95 65-69.9 52 5 11 7 11 7 11 2.71 70-74.9 46 6 4 11 11 4 10 2.72 75-79.9 40 12 5 5 10 3 5 2.05 80-84.9 10 2 1 2 4 1 3.10 HB 20-24.9 19 18 1 0.05 25-29.9 24 22 2 0.09 30-34.9 51 39 6 3 1 2 0.49 35-39.9 56 37 11 3 2 1 2 0.66 40-44.9 91 59 12 4 9 5 2 0.85 45-49.9 81 46 16 5 8 3 3 0.95 50-54.9 38 16 7 4 6 2 3 1.47 55-59.9 10 4 1 2 3 1.70 HH 40-44.9 15 9 2 . . 1 ? 1 1.20 45-49.9 75 44 12 7 4 5 3 0.97 50-54.9 121 71 19 8 7 7 9 1.07 55-59.9 83 54 7 9 4 4 5 0.94 60-64.9 16 4 4 2 2 4 1.88 NUMBERS OF AREAS OUT OF CONTACT In Table II several kinds of data are tabulated. The first column on the left indicates the number of specimens from the locality indicated having 0, 1, 2, 3, 4, or all areas "out of contact." In the next column these numbers have been converted into percentages of the total number of specimens used in this study from each locality. Then under the tabulations for each locality the average number of areas "out of contact" per specimen for the collection from the locality has been 172 I'KASERT LOHAVANIJAYA AND EMERY F. SWAN calculated. The average numbers of 1.77 for Crow Neck, 2.28 for Bailey's Mistake, 0.79 for Hampton Beach, and 1.06 for Hampton Harbor suggest that the Maine localities have populations that are more progressive in this respect than are those from the New Hampshire sites. Noting the size ranges from the localities (indi- cated on the table under the initials for the name of each locality) and recalling that numbers of areas "out of contact" presumably increase as the animals grow, one is immediately beset with the question : Are these differences the result of differences in environmental induction or selection on the one hand, or are they wholly the result of the differences in size-composition among the collections? Table III and 3.0 - 2.5 ^2.0 p 1/3 O> O 2 m rt 3 < 1.0 0.5 10 20 30 40 50 Mean diameter 1/2 (L+W) mm. 60 70 80 FIGURE 2. Relationship of the average number of areas "out of contact" to size 5 (L+W). Figure 2 have been assembled to show the mean numbers of areas "out of contact" at 5-mm. size (mean diameter) intervals for each of the localities. It is obvious that much larger collections and smaller si/.e intervals would be needed to give smooth curves on the graphs, but it is quite apparent that : (1) For comparable mean diameters up to at least 55 mm. the mean number of areas "out of contact" is higher for the (.'row Neck collection than for either Hampton Beach or Hampton Harbor, and (2) In the range of diameters between 55 and 70 mm. there appears possibly to be a tendency toward equal numbers of areas "out of contact" for all the localities. Thus for mean diameters of 62.5 mm., the mean numbers of areas "out of contact" for the collections from Crow Neck, Bailey's Mistake, and Hampton Harbor all VARIATION IN SAND DOLLARS. II. 173 fall within the range between 1.75 and 2.00. Although none of the specimens from Hampton Beach is this large, extrapolation of the plotted values for smaller sizes into this range would place the expected value for this locality very close to 2.00 areas "out of contact." APPARENT SEQUENCE OF Loss OF CONTACT IN INTERAMBULACRAL AREAS All possible combinations of areas "out of contact" were listed, and for each locality the number of specimens having each combination was tallied. Examination of these data along with Durham's (1955) Table 3 (p. 108) strongly suggested that the usual sequence in which interambulacral areas lose contact is 5, 1, 4, 2, 3. Thus, one would expect specimens "out of contact" for a single area to be most frequently "out of contact" in area 5. When two areas are "out of contact," areas 5 and 1 should be the most frequent combination. This would continue, and the whole expected sequence would thus be 0^5-^5 & 1^5, 1, & 4^5, 1, 4, & 2^5, 1, 4, 2, & 3 TABLE IV All possible combinations of normal, 1st order deviants, and 2nd order deviants Areas "out of contact" Normal 1st order deviants 2nd order deviants 1 2 3 All 5 5 & 1 5, 1 &4 Not possible 1 ; 2 ; 3 ; or 4 5, 2; 5,3; or 5,4 5, 1, 2; or 5, 1, 3 Not possible Not possible 1 '? 1 VI 1, - , 1, O , 1, 1, 2, 3; 1, 2, 4; 2, 3; 2, 4; or 3, 4 4; 1, 3, 4; 2, 3, 4; 2, 3, 5; 2, 4, 5; 4 5 (all) 5, 1,4&2 All 5, 1, 4 &3 Not possible or 3, 4, 5 1, 2, 3, 4; 1, Not possible 2,3, 5; or 2, 3,4, 5 ( all areas). These combinations are hereafter called members of the normal sequence. Durham's (1955) data for his series from Woods Hole, Massachusetts, and the data here presented in Table II for Crow Neck, Bailey's Mistake, and Hampton Beach support this sequence, or at least the resulting combinations that may be obtained through it. Thus, these combinations of areas "out of contact" are the most frequently occurring combinations in the collections aforementioned. Durham (1955) noted that the small collection (21 specimens) he studied from Hampton Harbor exhibited great variation in respect to loss of contact among the interambulacral areas. In the present study 310 specimens were examined from this locale, and Durham's conclusion is abundantly supported as can readily be seen from examination of Table II. The variants from these usual combinations may be conveniently divided into two categories. Cases where combinations include areas "out of contact" in the normal combination, except for the area presumed last to lose contact, are termed "first order deviants." Thus, any specimen having one area "out of contact" other than area 5 would be a "first order deviant." "First order deviants" with two areas "out of contact" must have one of these areas 5, and the other must not be area 1. "Second order deviants" are those combinations which do not include the presumed penultimate area among those "out of contact." Thus, for specimens 174 1'K ASKRT LOU. \\.\XIJAYA AND EMERY F. SWAN with two areas "out of contact," a "second order deviant" must not include area 5 among the areas "out of contact." In Table IV all possible combinations of "normal," "first order deviants." and "second order deviants" are indicated. All the theoretically possible combinations have actually been observed among the 1282 specimens dealt with in this section, except 2, 3 and 4. Tables V and VI indicate the numbers of each particular deviant found in each collection. In Table II the occurrence of "normal," "first order deviant," and "second order deviant" combinations are totalled for each collection for each number of areas "out of contact." TABLE Y .\nnihei- f ^f>eci metis of 1st order deviants in each collection Areas "out of contact" 1st order deviants CN BM HB HH Total Not possible 1 1 3 15 7 2 3 1 6 3 1 3 1 5 4 1 6 2 2 9 23 20 54 2 5 ^ 2 11 6 4 5 K 3 2 2 1 2 5 & 4 5 6 3 6 18 14 4 12 48 3 5, 1 ,V 2 7 6 3 2 5,' 1 ,V 3 8 13 1 15 19 4 2 40 4 5,1,4 & 3 15 15 3 4 37 5 (all) \:>t possible _ 179 Examination of these tables reveals that for the collections from Crow Neck and Bailey's Mistake, Maine, and Hampton Beach, New Hampshire, it is almost a generalization that for each number of areas "out of contact" there are more speci- mens with "normal" arrangements than with either first or second order deviant arrangements. The unique exception to this statement occurs among the specimens from Crow Neck with four areas "out of contact." Among these 38.2% have the "normal" arrangement and 44.1% have the only possible first order deviant arrange- ment that is, areas 5, 1, 4, and 3 "out of contact." There are, however, a few other situations (numbers of areas "out of contact" for given localities) where the sum of the first and second order deviants exceeds the number of "normal" individ- uals. But for the exception noted above, however, in no case does the number VARIATION IN SAND DOLLARS. II. 175 of individuals with any specific deviant even approach the number of "normal" individuals in these localities. For the collection from Hampton Harbor the situation is quite different. Although there is still a majority of these specimens with one area "out of contact" having the normal area 5 "out of contact," the percentage of these is much lower than found for the Maine localities and somewhat less than at Hampton Beach. In the group with two areas "out of contact" there is a total of only 26 specimens. TABLE VI Number of specimens of 2nd order deviants in each collection Areas "out of contact" 2nd order deviants CN BM HB HH Total Not possible 1 Not possible 2 1 &2 1 1 1 &3 2 1 &4 2 5 3 2 &3 1 2 2 &4 1 3 3 &4 1 2 8 12 22 3 1,2 &3 1 1 1, 2 &4 2 1 1 1, 3 &4 1 1 2, 3 &4 2, 3 & 5 3 4 3 2, 4 &5 2 2 2 3, 4 & 5 1 2 6 10 3 8 27 4 1, 2, 3 &4 1 4 1, 2, 3 & 5 1 5 2 2, 3, 4 & 5 4 2 1 6 7 7 20 5 (all) Not possible 69 Of these only two (7.7%} have the "normal" arrangement. While not much significance can be attached to these small numbers, it is interesting to note that the first order deviant arrangements of areas 5 and 4, and 5 and 2 and the second order deviants 1 and 4, and 2 and 4 "out of contact" all exceed the "normal" arrangement. These conditions suggest a tendency for areas 4 and 2 to lose contact ahead of sequence. Durham's (1955) data for this locality also indicate the tendency for area 4 to precede area 1. Second order deviants for specimens with three or four areas "out of contact" are also exceptionally high in this collection. 176 PRASERT LOHAVANIJAYA AND EMERY F. SWAN Here again we suffer from small numbers, but the tendency could be readily ex- plained on the basis of deviant sequence's early in their development. Why the sequence of loss of contact among the interambulacral areas is so unusual at Hampton Harbor is a difficult question to approach. It seems in- comprehensible that the Hampton Harbor population is genetically isolated from those of Hampton Beach hardly a mile distant by interconnecting water. However, there still exists the possibility that even from a common gene pool and common reservoir of larvae, there could be a selective difference of survival among genotypes TABLE VII Nu tubers and percentages of specimens, asymmetrical around the interambulacral radii, having "b" (H and -\-(>) and having more contact with "b" than (0+ and h) according to area of test and locality of collection Area Series i and + +and - + No. % No. % 1 CN 179 98.4 3 1.6 BM 128 98.5 2 1.5 HB 239 83.3 48 16.7 HH 225 97.0 7 3.0 2 CN 22 11.2 175 88.8 BM 24 13.6 152 86.4 HB 64 29.5 153 70.5 HH 74 36.8 127 63.2 3 CN 110 60.8 71 39.2 BM 120 78.9 32 21.1 HB 99 47.6 109 52.4 HH 136 70.5 57 29.5 4 CN 4 2.0 201 98.0 BM 0.0 175 100.0 HB 19 7.0 254 93.0 HH 3 1.3 236 98.7 5 (A 0.0 62 100.0 BM 4 5.3 72 94.7 1115 9 4.1 211 95.9 HH 12 6.4 176 93.6 after metamorphosis. The other likely explanation is that the differences in environmental factors between these proximate localities may affect genetically-like organisms in such manner that they develop differently. Regardless of whether these differences are genetic or environmentally induced, there still remains the question as to what environmental factors might be involved. A somewhat similar problem concerning variation in the heart-urchin, Echlnocardhim cordatmn Pennant, it occurs in British and nearby waters lias been carefully studied by Nichols ( \'H>2), who suggests functional advantages for the variants he studied and favors the explanation of differences between populations as resulting from differential selection. VARIATION IX SAND DOLLARS. II. 177 ASYMMKTRY WITHIN I NTERAMBULACRAL AREAS Differences in the amount of contact between first post-basicoronal plates "a" and "b" with the basicoronal plates cause deviations from the symmetrical arrangements of plates on the two sides of the radius running through the middle of the area in question. Table I summarizes the number of individuals having the various types of contact, or lack of it, between the first post-basicoronal plates and the basicoronal plates for each of the interambulacra in the specimens collected from Bailey's Mistake and Crow Neck, Maine, and Hampton Beach and Hampton Harbor. New Hampshire. Inspection of this table indicates that in areas 1, 2, 3, 4, and 5, plates "b", "a", "b", "a", and "a", respectively, appear to lose contact more frequently ahead of the other member of the pair. It can readily be seen from Table VII that the degree of preponderance varies among the areas and within areas among the collections from different localities. DISCUSSION The loss of contact between first post-basicoronal interambulacral plates and the basicoronal plates varies in respect to number of areas involved, apparent se- quence among areas, and in the asymmetry of contact within the areas which appear to be in the process of losing contact. The number of areas "out of contact" is subject to increase as the individual grows at least initially. Thus, specimens with (or populations averaging) more areas ''out of contact" may be thought of as being more advanced or progressive. This agrees with Durham's (1955) idea that primitive genera and species near the ancestral stock retain contact whereas more highly evolved taxa are characterized by increasing loss of contact. Among the regular echinoids Jackson (1912) on similar grounds considered the exsert condition of ocular plates to be primitive and the insert condition more progressive. From the studies of Jackson (1912), Vasseur (1952), and Swan (1958, 1962) it appears that for Strongylocentrotus higher salinities and lower temperatures go hand in hand with the more progressive development characterized by more ocular plates insert. For the tropical TripncHstes, however, Jackson's (1914) data suggest the opposite relationship with temperature. E. panna is essentially a boreal species, and the higher numbers of areas "out of contact" in the collections from Maine, indicating that they are more progressive, might suggest that this species, like Strongylocentrotus, attains a more progressive condition in cooler water. Much caution should be used, however, in making even tentative conclusions on tin- basis of these few data. One cannot determine a trend from two points (the New Hampshire series as compared with those from Maine) ; and when the mean number of areas "out of contact" is calculated for Durham's (1955, Table 3, p. 108) series of E. panna from Woods Hole, Massachusetts, the value obtained is 1.71. At first glance it is apparent that this figure is nearly up to the overall average value for Crow Neck, Maine; but when the effect of the size of the specimens is considered, conclusions based on comparison of these overall averages become obviously questionable. If the specimens Durham (1955) used for his Table 3 are the same ones used for Table 2, which were said to range from 50 to 62 mm. in average diameter, they are in the size range where a convergence 178 PRASKRT LOHAVANIJAYA AND KMKKY F. SWAN in numbers of areas "out of contact" occurs among the collections from Maine and N'ew Hampshire and thus indicate 1 little. This convergence, as shown in Figure 2. makes one wonder if the loss of contact by additional areas may not cease when a certain size or age is reached. As shown hy Jackson (1912) and verified by Swan (1958), this appears to be the case for ocular plates becoming insert in Strongylocentrotus drocbachlcnsls. The arrange- ment of points (Fig. 2) relating average numbers of areas "out of contact" to mean diameter for the sand dollars from Crow Neck certainly appears to suggest a curve becoming asymptotic to the base line at some value between 1.75 and 2.00 areas "out of contact" for diameters above about 45 mm. For diameters of 45 mm. and less the "curve" for the population from Hampton Beach appears to be roughly parallel to that for Crow Xeck but is displaced toward lower numbers of areas "out of contact" at comparable diameters. There is no indication of flattening out <>f this curve at mean diameters near 45 mm., and no specimens were available for sixes that were appreciably above the diameters where the mean number of areas "out of contact" reached 1 .70. The size ranges of the series from Bailey's Mistake and from Hampton Harbor are such that they give little help toward answering questions, but the great fluctuation shown in the series from Bailey's Mistake in regard to numbers of areas "out of contact" intensifies another question suggested by the "curve" representing the Crow Neck population. If there is a limit beyond which no further areas lose contact, does the value of this limit fluctuate? If so, \\liy? These remain as problems for future attack. Before leaving this subject, we should be reminded of the fact that Durham's (1955) findings would suggest that in sand dollars new plates on the oral side of the test are added up to a certain small size, after which no more are added. The variation he notes in the numbers of these plates in /:. panua might be related to differences in the time at \\liich their addition ceases in different individuals. That the addition of coronal plates may cease before regular urchins die or cease growing is indicated by Hsia (1948) for two species of Tcnnwplcnnts. No work is known to the present authors which indicates whether or not the size or number of plates at which this occurs varies within the species from one population to another. Again the temptation to make comparisons with better known organisms in other phyla is strong. A great many studies have been made on the numbers of vertebrae, fin-rays, and other serially repeated structures in fishes; and generally it appears that longer developmental periods (i.e., slower growth through the critical stages in develop- ment) produce higher counts in meristic structures. Low temperatures, high salinities and low oxygen tensions have been shown to retard development and produce this effect. Much of the pertinent literature on this subject has been discussed and listed by Barlow (1961). That light may also affect the number of vertebrae formed appears to be the case in at least some instances (McHugh, N54). Perhaps it is no mere coincidence that Strongylocentrotus appears to progress further in its attainment of insert ocular plates in colder or more saline waters and that Echinarachnius tends to progress toward having more inter- ambulacral areas "out of contact" in eastern Maine than in Xew Hampshire. It would be interesting to check the numbers of plates on the oral surfaces of the series from colder and warmer water to see if those from colder water had a higher average number. VARIATION' IX SAND DOLLARS. II. 17') The sequence of 5, 1, 4, 2. 3 in which interamhulacral areas lose contact is of more than a little interest. Although in Strongyloccntrotus the normal sequence in which oculars hecome insert is I, V, IV, II with no record of all oculars insert, there are many genera of regular urchins where the normal sequence is V, I, IV, II, III (Jackson^ 1912). Jackson (1912, 1914), Vasseur (1952), and Swan (1962) have all noted that localities differ from one another in respect to the frequency with which aherrant variant comhinations of oculars insert occur in various species of regular urchins. Thus, the fact that one of the localities here studied (Hampton Harbor) is characterized by so many deviant arrangements of areas "out of contact" among its sand dollars is not surprising, but at present no explanation can be sug- gested. Swan (1962) has noted that certain aberrant variant arrangements of ocular plates insert in Strongyloccntrotus are indicative of ''situs inrcrsus." The possibility that some of the deviant arrangements of areas "out of contact" in Echinarachnius may also indicate such deep-seated reversals of asymmetry should be more carefully checked. Initial examination of the first post-basicoronal ambu- lacra! plates revealed no deviations from conformity with Loven's (1874) law (cf. p. 104, Durham, 1955) that would suggest a reversed pattern. If all specimens or any suspected of being reversed were cut frontally or examined with a fluoroscope, it should be possible to determine the course traversed by the digestive tract and get the best evidence from internal anatomy. The pattern of asymmetry around the central axes through the interambulacral areas is very strongly marked in areas 1, 4, 5, fairly strongly marked in area 2, and rather weakly marked in area 3. It is possible that the deviations from the usual arrangements here too might be symptomatic of the more deep-seated "situs inversiis." In some respects this study may be considered as an extension of Durham's (1955) notable work, which owed a great deal to the earlier thinking of numerous workers, of whom Loven (1874) and Jackson (1912) must be singled out as especially important. At the same time it is obvious that in the present work there are more new avenues of investigation suggested than problems completely solved. Workers desirous of making additional studies of variation in irregular urchins should, in addition to the approaches used here, become thoroughly ac- quainted with the methods of Kongiel (1938), Kermack (1954), Nichols (1959a. 1959b, 1962) and Kier (1962). SUMMARY 1. The general arrangement of plates on the oral surface of sand dollars is discussed. 2. Variations in this arrangement as they occur in Echinarachnius panua from several New England localities are indicated. 3. As this sand dollar increases in size, there is decreasing contact between the post-basicoronal interambulacral areas and the basicoronal plates. 4. The usual sequence in which this contact is lost among the areas is 5, 1. 4, 2 and 3, but all possible combinations of areas "out of contact" have been observed, except 2, 3 and 4. 5. The average numbers of areas ''out of contact" for animals of comparable sizes vary among localities. ISO PRASERT LOHAVANIJAYA AND KMKKV F. SWAN <>. The asymmetry of loss of contact \vitliin the interambulacral areas has also been found to be highly variable. 7. The possibility that these variations may be- related to differential environ- mental effects upon the rates at which different parts of the growth process occur is suggested. LITERATURE CITED HAKI.OW, G. YV., 1961. Causes and significance of morphological variation in fishes. S\st. Z<>1., 10: 105-117. llrkiiAM, J. \V., 1955. Classification of Clypeasteroid Echinoids. U. of Calif. Pub!. Gcol. Sci., 31: 73-198 + frontispiece and plates 3 and 4. HSIA, W. P., 1948. On the relations between the number of coronal plates and the diameter of the test in three species of sea urchins. Contr. lust. Zool. Natn. Acad. Pcipiin/, 4:25-30. JACKSON, R. T., 1912. Phylogeny of the Echini, with a revision of Palaeozoic species. Man. Boston Soc. Xat. Hist., 7, 491 pp. + 76 plates. JACKSON, R. T., 1914. Studies of Jamaica Echini. /'<//>. Tortitfias Lab. (Pub!. No. 1S2 Cam. lust.}, 5: 139-162. KERMACK, K. A., 1954. A biometrical study of Micrastcr coranguinum and M. ( Isomicrastcr} scnoncnsis. Phil Trans. Roy. Soc.' London, 237B: 375-428 + plates 24-26. KIEU, P. M., 1962. Revision of the cassiduloid echinoids. Smithson. Misc. Coll., 144: 1-262. KOXGIEL, R., 1938. Rozwazania nad zmiennoscia jezowcow. (Considerations on the variability of Echinoidea. ) Annalcs Soc. gcol. Polofinc, 13: 194250. (In Polish with French summary and legends for figures and tables. English translation OTS 60-21506 available from the Office of Technical Services, U. S. Department of Commerce, Washington 25, D. C.) LOHAVANIJAYA, P., 1965. Variation in linear dimensions, test weight, and ambulacral pores in the sand dollar Echinaracliniiis panua (Lamarck). Diol. Bull., 128: 401-414. LOVEN, S., 1874. fitudes sur les fichinoidees. Kon</l. Srcnska J'ctcnsk. Akad. Hand!., Stock- holm, licit.' scries, 11. 91 pp. + 53 plates. Mi HUGH, J. L., 1954. The influence of light on the number of vertebrae in the grunion, Lcurcstlics tennis. Copeia, 1954: 23-25. NICHOLS, D., 1959a. Changes in the chalk heart-urchin Micrastcr interpreted in relation to living forms. Phil. Trans. Roy. Soc. London, 242B: 347-437 + plate ix. NICHOLS, D., 1959b. Mode of life and taxonomy in irregular sea-urchins. Systematics Associa- tion Publication, No. 3, pp. 61-80. 7 figs. NICHOLS, D., 1962. Differential selection in populations of a heart-urchin. Ibid. Publ. No. 4, pp. 105-118, 8 figs. .SwAN, E. F., 1958. Growth and variation in sea urchins of York, Maine. J. Mar. Res., 17: 505-522. S\VAN, E. F., 1962. Evidence suggesting the existence of two species of Strongylocentrotus (Echinoidea) in the Northwest Atlantic. Camid. J. Zoo!.. 40: 1211-1222. VASSEUK, E., 1952. Geographic variation in the Norwegian sea urchins, Strongylocentrotus droebachicnsis and 5". pallidns. Evolution, 6: 87-100. CHROMOSOMES OF TWO SPECIES OF QUAHOG CLAMS AND THEIR HYBRIDS R. WINSTON MENZEL AND MARGARET Y. MENZEL 1 Oceanographic Institute and Department of Bioloi/ical Scienee, The Florida State University, Tallahassee. Florida 32306 Two species of quahogs (clams of the genus Merccnaria, formerly Venus) occur along the Atlantic and Gulf coasts of North America. Abbott (1954) char- acterizes the two species as follows: The northern quahog, Merccnaria incrccnaria (L.), ranges from the Gulf of St. Lawrence to Florida and the Gulf of Mexico. It has a characteristic smoothish or glossy area on the exterior center of the valves. The interior of the valves is white and commonly has purple stainings. The entire lunule is three-fourths as wide as long. Two subspecies are listed: M. in. notata Say with external zigzag brown mottlings and M. in. tc.vana Dall, from the northern Gulf of Mexico, with large irregular coalescing flat-topped concentric ribs. The southern quahog, M. campechiensis (Gmelin), ranges from the Chesapeake Bay to Florida, Texas, and Cuba. It has a more obese shell and lacks the smooth central area on the exterior of the shells. The entire lunule is usually as wide as long. Rarely are there brown mottlings on the exterior of the valves, which are always white internally. It is often difficult to assign a specimen to either species if a single character is considered. Fast-growing specimens of M . mercenaries, less than about 25 mm. long, lack the characteristic glossy smooth area on the exterior of the valves. Meas- urements of length and weight of the two species, grown under the same conditions, have shown the small M . uicrccnaria to have heavier shells than M. campechiensis of the same length. ( Hherwise typical individuals of M. cainpechicnsis occur with internal purple shell stainings and with the brown mottlings of the subspecies M. in. notata. Often the lunule of 717. campechiensis is only three-fourths as wide as long. The two species hybridize readily in the laboratory (Loosanoff, 1954). This paper reports chromosome numbers and behavior in the two species and their hybrids at meiosis and early embryonic mitoses. MATERIALS AND METHODS Live specimens of M. mercenaria were secured from Connecticut, New York, Delaware, Virginia, North Carolina, South Carolina and the east coast of Florida. The southern quahog was obtained from North Carolina, the east coast of Florida and several localities along the Gulf coast of Florida from Tampa Hay northward. These clams have been used in several ways: for growth experiments (Menzel, 1961a, 1962); for clam farming observations (Men/el. l'MI>; Menzel and Sims, 1962) ; and as brood clams for observations on hybrids (Menzel, 1964). In addi- 1 Contribution No. 207 from Oceanographic Institute, The Florida State University, Tallahassee, Florida. 181 182 R. WINSTON MENZEL AX I) MARGARET Y. MENZEL / V * A I t I * S V l .v Jjf ^ t FIGURES 1-5. . 4 -. ;- 3 * f* / CLAM CHROMOSOMES 183 tion, laboratory-reared hybrids have been available from the Biological Labora- tory, Bureau of Commercial Fisheries, Alilford, Connecticut, and from the marine laboratory of the Oceanographic Institute. Crosses have been made in our lal (oratory using as brood clams hybrids grown to sexual maturity here and the two species from localities listed above. These crosses include intraspecific crosses, reciprocal crosses of the two species (F/s), F 2 's of the hybrids 5 .17. campechiensis X J* .17. inercoiaria and reciprocal back- crosses of the latter F t to each species. All of the above combinations have been spawned and reared beyond metamorphosis and settling by the techniques of Loosanoff and Davis (1963). Observations of meiosis in eggs from F\ hybrids reported here were all made on hybrids from crosses between ,17. incrccnaria males from Connecticut and .17. campechiensis females from Florida. At intervals after spawning, the eggs and embryos were fixed in freshly mixed acetic alcohol (three parts absolute ethanol, one part glacial acetic acid) and stored in a freezer at 16 to 18 C. Several dozen embryos in a small drop of fixative were placed on a slide and air-dried or flamed. Several drops of iron-acetocarmine were added and allowed to stain for two minutes. A coverslip was added and excess stain removed by blotting. The coverslip was pressed firmly on the slide and the preparation was then heated judiciously over an alcohol flame to clear the cyto- plasm and further flatten the eggs. Such temporary squashes usually were examined at once with a Zeiss microscope equipped with an apochromatic optical system and phase contrast accessories, but they could be stored for several days at 2-4 C. without severe deterioration. Chromosomes prepared in this way were usually well spread but rather lightly stained. Substitution of aceto-orcein, propio-orcein, Gomori's chrom-alum-hema- toxylin and Feulgen staining did not result in significantly better preparations. Phase-contrast illumination of the acetocarmine slides was used routinely to enhance contrast and facilitate analysis. Stages of meiosis from metaphase I to telophase II and mitotic figures from early cleavage divisions were readily observed by this method. Because of the dense cytoplasm and tough egg membranes, the eggs were difficult to flatten sufficiently for microphotography. Hence, most of the stages described here are illustrated with drawings made with the aid of a camera lucida. Preparations from M. campechiensis were consistently better than those from the F x hybrid, which were in turn better than those from M . nicrccnaria. OBSERVATIONS Early embryology Eggs fixed from 15 seconds to 5 minutes after spawning contained oocyte nuclei at metaphase I regardless of whether sperm suspension had been added. If the eggs were not fertilized, the oocyte nuclei remained at metaphase I for 60 minutes or longer and then gradually degenerated in situ. In one unfertilized lot of eggs, FIGURES 1-5. Photomicrographs of meiotic metaphase I in clam eggs, phase-contrast illumination. Some of the bivalents are out of focus in each photograph. FIGURE 1. Mcrccnaria campechiensis, same nucleus as Figure 8, X 900. FIGURE 2. M. campechiensis, same nucleus as Figure 10, X 900. FIGURE 3. Individual bivalents of nucleus shown in Figures 2 and 10, X 1800. FIGURE 4. Fi hybrid, X 900. FIGURE 5. M. mercenaries, same nucleus as Figure 12, X 1800. 1S4 R. WINSTON MENZEL AND M ^RGARET \. MRXZEL " 1 " Vf V 4' v i/ \fi * 7 l ; K,i'KK 6. Mi-tapliHsc of the second cleavage division in a lcrtilize<t egg of Mcrccmind cuinpccliicnsis, 38 chromosomes. Acetocarmine staining, X 1800. FIGURK 7. Metapliasc of normal first cleavage division, I-\. hybrid, 38 chromosomes. Acetocarmine staining and phase-contrast illumination, X 1800. though degenerating nictapliasc I configurations were present 20 hours after spawning. Jf an effective sperm suspension \vas added, meiosis proceeded rapidly, the first polar body appearing in 10 minutes, and nietaphase II in 15 niin- nte>. From nietaphase 1 through telophase II the sperm pronucleus was dis- cerned as an increasingly diffuse' nucleus lying at some distance from the meiotic spindle.^. Fusion of the egg and sperm proiiuclei was not identified with certainty but probablv occurred when the chromosome's ol both were in a mid-prophase CLAM CHROMOSOMES 185 condition preceding formation of the first cleavage spindle. The first cleavage division of the zygote nucleus ensued as early as 20 minutes and usually within 30 minutes after spawning. Subsequent cleavage divisions followed rapidly; eggs 75 minutes after spawning and contact with sperm suspension often contained too many dividing nuclei for analysis. Systematic comparisons of the timing of development in the various types of fertilizations were not made. Preliminary observations suggested that fertilizations in which sperm from the F, hybrids were used (backcrosses to both parental species and F 2 ) were followed by somewhat delayed development. In one lot of F 2 embryos fixed on October 27, 1964, first cleavage metaphase and anaphase were found in lots fixed 45-75 minutes after sperm contact. Among 18 embryos in which chromosomes could be counted. 5 were diploid, 4 triploid (Fig. 16), 7 tetraploid, one had a chromosome number (46) between diploid and triploid. and one egg had a diploid and a separate haploid nucleus, both at metaphase. Subsequent lots of eggs from similar fertilizations did not exhibit polyploidy (Fig. 7). Occasionally an early embryo with dividing haploid nuclei was observed in batches of eggs which had not been fertilized either because sperm were not added or because the sperm were ineffective. A careful comparison of rates of development under controlled conditions should be made. Chromosomes Both M. incrccnaria (Figs. 5, 11, 12) and M. cainpccliicnsis (Figs. 1-3, 8-10) have 19 pairs of chromosomes at metaphase I and 38 chromosomes at embryonic mitoses (Fig. 6). At metaphase I the chromosome pairs are small and slender and the chromatid split can often be discerned. Most of the chiasmata do not terminalize until the onset of anaphase. A typical nucleus from M. campechiensis (Fig. 9) showed 19 bivalents with 27 unterminalized and 8 nearly or completely terminalized chiasmata (1.89 chiasmata per chromosome pair). The metaphase I bivalents of M. mercenaria are similar, but in our material tended to be more compact and hence less easily analyzed for chiasma frequency and position. The F, hybrid was intermediate in this regard, some figures approaching those of M. campechiensis in clarity (Figs. 4, 13, 14). In the F, hybrid all the chromosomes were paired regularly as 19 homomorphic bivalents at metaphase I. The chiasma frequency was not conspicuously different from those of the parents. Later stages of meiosis proceeded conventionally in the two species and in the hybrid. In one batch of eggs from the hybrid, two anaphase I figures showed an apparent bridge between the two groups of chromosomes, one of which is shown in Figure 15. Since no fragments were found, the bridges probably resulted from lagging separation of chiasmata rather than from crossing-over within a heterozygous inversion. At anaphase I in both species and the hybrid the chromo- somes at one spindle pole were commonly more compact and darkly stained than those at the other. In our squashes we were unable to tell whether either the darker or lighter group was consistently destined to be included in the first polar body. The mitotic chromosomes of the first and second cleavage divisions were rather long and very slender (Figs. 6. 7) but tended to become shorter and more compact, at least at metaphase, in later divisions. I'.ecause of the rather high chromosome 186 R. WINSTON MH\/KL AND MARGARET Y. MENZEL 8 /> 1 r V S '. 16 8-16. ChroinoMHiir-, in fertili/ed clam ra Incida ; all X 900 except Figure 15, X 1125. n \ 10 13 14 Drauin.us maik- with tlu 1 aid of a CLAM CHROMOSOMES 187 number and small cells, it was not practicable to count tbe chromosomes of individual nuclei after the second cleavage mctapliase. The individual chromosomes exhibited a rather wide range of relative lengths and of arm length ratios. Since the meiotic bivalents of the hybrid revealed no evidence of structural differences between tin- two species, detailed comparisons of mitotic karyotypes were not made. DISCUSSION The ease with which hybrids between M. nicrccnarla and .17. cainpecliicnsis can be made experimentally and the existence in nature of forms which can be interpreted as intermediate suggest that a certain amount of gene flow may occur between the two taxa. The homology and regular behavior of the chromosomes of the two species revealed at meiosis in the F i hybrid demonstrate that there is no gross chromosomal barrier to such gene interchange. Ability to exchange genes under experimental conditions does not, of course, imply that such interchange actually does occur in nature. Mayr (1963) has re- cently reviewed the mechanisms which may serve to keep populations separate even though they are sympatric in part of their range and can be successfully hybridized under experimental conditions. Porter and Chestnut (I960) suggested that in the region of Beaufort, North Carolina, where 717. incrccnaria is confined to inland bays and inlets and J\I. cawipechiensis to outer shallow neritic waters, the two populations may be effectively separated by differential tolerance to salinity. The preliminary observations of F._, and back-crosses suggest also that embryos of the species may have an advantage in rate of development over the hybrid offspring under certain conditions. Regardless of whether and to what degree hybridization and gene exchange between J17. mercenaria and 717. campechiensis occur in nature, results so far suggest that their hybrids could furnish an important source of variation for the selection of improved strains of clams for commercial production, especially for regions in which the commercially less desirable 717. campechiensis is naturally better adapted. The authors gratefully acknowledge initial financial support from the Graduate Research Council, Florida State University, and the assistance of Mrs. Clare Shier in preliminary cytological study. Numerous individuals are thanked for kindly furnishing brood clams. SUMMARY Chromosome numbers of n -- 19. 2n -= 38 are reported for Mercenaria mer- cenaria, M. campechiensis and their F l hybrids. Meiosis is normal in the hybrids FIGURES 8-10. Meiotic metaphase I in Mcrccmiria cainpcchicnsis. 19 bivalents, mostly with one or two unterminalized chiasmata. Figure 8 is the same nucleus as Figure 1 ; Figure 10, the same as Figures 2 and 3. FIGURES 11, 12. Meiotic metaphase I in M crcciuiria incrccnaria, 19 bivalents. Figure 12 is the same nucleus as Figure 5. FIGURES 13, 14. Meiotic metaphase I in the Fi hybrid, 19 bivalents, the chiasma frequency not conspicuously different from that of the parents. FIGURE 15. Anaphase I in the Fi hybrid showing one bridge or (more likely) pseudobridge. FIGURE 16. Metaphase of an aberrant triploid first cleavage division, F- hybrid, 57 unusually short chromosomes. 188 R. WINSTON MF.XZEL i XI) M \ROARET Y. MENZEL and yields no evidence of chromosoiiu- nonhomology or structural rearrangements between the two parents. Hie hybrids produce functional eggs and sperm which result in normal fertilixation and earl\ embryonic divisions in reciprocal backcrosses and at least some Iv.'s. Xo gross chromosomal barrier to gene exchange appears to exist between the two species. LITERATURE CITED ABBOTT, R. T., 1 1 '54. American Seashells. 541 pp. D. Van Nostrand Co., Inc., New York. Loos AX OFF, Y. I... I n 54. Xew advances in the study of bivalve larvae. Aiuer. Scientist, 42: 607-624. LOOSAXOKF, Y'. L., AMI IL C. DAVIS, 1963. Rearing of bivalve mollusks. In: Advances in Marine Biology, I, pp. 1-136. Academic Press, Inc. (London) Ltd. MAYR, E., 1963. Animal Species and Evolution. 797 pp. Harvard University Press, Cam- bridge, Mass. MKXZEL, R. W., l%la. Seasonal growth of the northern quahog, Merccnar/d nierceuarid, and the southern quahog, M. cdinpccliicnsis. in Alligator Harbor, Florida. Proc. Nat!. Shellfish. Assoc., 52: 37-46. MENZEL, R. \\'., l ( 'nlb. Shrlllish mariculture. Proc. (ailf and Caribb. Fish. Inst., pp. 195-199. 14th Annual Session. MKXZEL, R. W., 1 ( '62. Seasonal growth of northern and southern quahogs, Mcrcciidrin incrct'iiitrid and M. cinnpccliit'iisis, and their hybrids in Florida. Proc. Xdtl. Shellfish. Assoc., 53: 111-119. MKXZEL, R. W., 1964. Observations of quahog clams and their hybrids. Amcr. Ziml., 4(3) [Abstract]. MKX/KL, R. \\'., AMI 11. W. SIMS, 1962. Experimental fanning of hard clams, Mcrccuana iiicrccnurid, in Florida. Proc. Nail. Slid! fish. Assoc., 53: 103-109. PORTER, H. J., AND A. F. CHESTNUT, 1960. The offshore clam fishery in North Carolina. Proc. Nut!. Shellfish. . Issoc., 51: 67-73. STUDIES ON TH K ( )( >PLASMIC SEGREGATION IN THE EGG OF Tl 1 K FISH, ORYZIAS LATIPES. III. ANALYSIS OF THE MOVEMENT OF OIL DROPLETS DURING THE PROCESS OF ( )OPLASMIC SEGREGATION YOSHI T. SAKAI 1 Department of Bioloiiy, Tokyo Metropolitan Unircrxlty, Tokyo, Jupun Ooplasmic segregation, which generally occurs following fertilization in fish eggs, leads to the formation of the blastodisc. Studies of this movement have heen done by Spek (1933; Corregotnis, Saliuo, etc.), Roosen-Runge (1938; Brachy- danio), Lewis (1949; Brack yd an io ), and Costello (1948; Nerds'), etc. Although much attention has heen paid to the protoplasmic movement in the yolk or endoplasmic region, observations on the movement in the cortical proto- plasmic layer (cortex) have been restricted to the eggs of Brachydanio (Roosen- Runge, 1938) and of (,'astcrostcits (Thomopoulos, 1953), neither of which have oil droplets in the cortex. In Orysias eggs, the protoplasm and yolk are well separated before fertilization and oil droplets are dispersed in the former. On fertilization, the oil droplets move toward the vegetal pole at a speed which can be measured accurately. The present paper deals with analysis of the pattern of the movement of oil droplets, both natural and injected, during the formation of the blastodisc in Oryzias eggs. PART I. MOVEMENT OF NATURAL OIL DROPLETS METHODS After fertilization in Oryzias. evenly dispersed oil droplets in the unfertilized egg cortex migrate toward the vegetal pole, fusing with each other, and finally assemble around the vegetal pole, turning the egg upside down within the chorion by buoy- ancy. Therefore, to prevent the rotation of the egg during observation, the egg must be placed with the animal pole down from the beginning, and fertilized ; it is photo- graphed simultaneously from the animal, vegetal and lateral sides at intervals of two minutes. The photographs of the egg are magnified 100-fold and superimposed to trace the movement of the oil droplets. In the polar views, the distance along the curved surface bet ween the oil droplets and the animal or vegetal pole is calculated from the tracings of the photographs. In the side view, the equator of the egg is taken as a reference line and the distance of the oil droplets from the line is calculated. Since the tracings of the moving oil droplets are almost parallel to the longitude of the egg. sidewise shifts of the droplet are neglected ( Fig. 1 ) . 1 Present address : Dcpartnu-nt of Zoology, University of California, Berkeley 4, Calif. 189 190 YOSHI T. SAKAI AP l-'li.l KK 1. Tracings of moving oil droplets during ooplasniic segregation. AP : animal pole; VP : vegetal pole. In the calculations, the egg is considered as a sphere. Since the egg is not strictly a sphere hut rather an ellipsoid of revolution, the error coming from the approximation must he determined. In Figure 2, S is a sector of a sphere and E is that of an ellipsoid of revolution, a and b being the major and the minor axes of the IMI.I KK 2. Procedure to obtain the- actual distance or the angle from an apparent distance on the surface of sphere and of ellipsoid of revolution. S: a sector of a sphere; E: a sector of .HI ellipsoid of revolution; A : position of an oil droplet; a: major axis of ellipsoid of revolution; h: minor axis of the ellipsoid of revolution; \: apparent distance of an oil droplet from the reference lin< (equator); y: actual distance on the: sphere; z: actual distance of x of the ellipsoid of revolution ; : the angle at the center of the sphere embracing y. OOPLASMIC SEGREGATION IN FISH EGG 191 latter. "A" represents the position of an oil droplet under observation and x is its apparent distance from the reference line, as expressed in an angle at the center embracing x ; y is an arc of the circle and z is a section of the ellipsoid, which are the actual distances along the curved surfaces corresponding to the apparent distance x of the sphere and the ellipsoid of revolution, respectively. In other words, the aim of the calculation is to obtain either y or z from x. -90 TIME AFTER FERTILIZATION (MIN) FIGURE 3. Time courses of the migration of oil droplets in terms of (22 C.). Ordinate : the value of Q, taking an equator as ; abscissa : time after fertilization in minutes. AP : animal pole; VP: vegetal pole; EQ : equator; arrow: fusion of oil droplets. Alphabetic designation of the curves is for use in Figure 4. In the Orysias eggs used for the present measurements, the deviation of the ellipsoid from the sphere, a b/a, is not larger than 0.08. For simplification of the calculation, a b/a is taken as 0.10. On the basis of these figures, the deviation of z from y, z y/z, turns out to be less than 0.03, which means that the error involved in the approximation as a sphere is negligible. The measurement lor the region above \/3/2 b (60 in 6) is supplemented by the measurements in the polar views. Since an egg can be treated as a sphere, distances through which the oil droplets move can best be expressed in 8 because 9 is independent of individual fluctuation in the egg size. 192 YOSHI T. SAKAI K' -i I.TS Figure 3 compares the time course of the migration in H of oil droplets initially located at different regions of the egg. \\'itliin 2-4 minutes after fertilization, almost all the oil droplets shift transiently toward the animal pole to some extent (see the left end of Fig. 3). This shift is rather difficult to discern unless one is aware of this phenomenon beforehand. During this period, a decrease in the egg volume takes place in Oryzias as the result of the breakdown of cortical alveoli (T. Yamamoto, 1940). However, since the distance is expressed in #. the decrease in the volume does not affect the measurement as long as the shrinkage occurs uniformly. Corre- spondingly to this stage when the animal region of the Oryzias egg is seemingly 2.0 1.0 en O (T B o D ^E -3 F 20 30 40 50 60 TIME AFTER FERTILIZATION (MIN) FIGURE 4. The ratio between the distance in ft of the reference oil droplet ( R ) from the base line (60) and the distance of a given oil droplet (A, B, C, D, E and F) from the line (60) at specified moments (a/'r, h/r, c/r, cl/r, e/r and f/r). Ordinate : ratios a/r, h/r, c/r, d/r, e/r and f/r; abscissa: lime after fcrtili/ation. contracting. Roosen-Runge ('1'MSj describes, in I'rarliydanio eggs, an increase of the egg diameter and flattening of the animal pole region, as observed from the upper side. .According to the present writer's observations of Hniclivdiniio eggs made at this stage from the side, the egg flattens and so does the blastodisc region. Whether or not this flattening of the blastndisc nrion means a contraction at the animal region cannot be said at present. In Oryzias, the oil droplets remain stationary thereafter for about 20 minutes, alter which the movement of the oil droplets is resumed and they move toward the vegetal pole. This movement is particularly striking on the animal half. < )n the other hand, the vegetal oil droplets, originally located within 30' in H from the vegetal pole or beyond 60 on the ordinate of Figure 3, continue to move toward the animal side' even alter the transient shift is over. Consequently, all the 1 OOPLASMIC SEGREGATION IN FISH EGG 193 droplets are assembled at the latitude of about 60 as a ring. It must be mentioned that the ring eventually reaches the vegetal pole after several hours, by the morula stage (omitted from Fig. 3). If the migration speeds of the oil droplets starting from various levels of the egg are compared at various moments after fertilization, it can be said that the higher the curve, the steeper the inclination, which means that the closer an oil droplet is to the animal pole, the faster it moves. Next, the latitude of -60 to which the oil droplets gather is taken as a base line, and the positions of seven droplets, A, B, C, D, K, F and R (Fig. 3) from the new base line are read in 9 (a, b, c, d, e, f and r) for 20, 30, 40, 50 and 60 minutes after fertilization. In Figure 4, the ratios a r, b/r, c/r, d/r, e/r and f/r at the specified moments are plotted. As is clear, the ratios for respective droplets remain almost unchanged during the migration. This means that these droplets approach the base line at a speed proportional to the original distance of the oil droplet from the base line, theoretically reaching the base line simultaneously, which is more or less what is observed. The tracings of the oil droplets look as though the droplets might be attached to a stretched rubber membrane and carried to\varcl 60 in by the snapping of the membrane, as the result of breaking at the two poles. As is well known, the oil droplets frequently fuse with each other during the migration. When this happens, the speed of the fused droplet comes close to that of the slower or larger partner (see Fig. 3). DISCUSSION Transient shift of oil droplets toward the animal pole immediately jollowiny activation From the previous study by the author (Sakai, 1961 ), the unfertilized egg of Oryzias, deprived of the chorion, is flattened when observed from the side. On fertilization or activation, the egg is further flattened in the region where the cortical response is taking place. This flattening (decrease of the tension at the surface) spreads from the activated point with the wave of breakdown of cortical alveoli. After 2-4 minutes, when the cortical change is almost completed, the egg begins to bulge again from the activated point (Sakai, 1961). In the fertilized egg enclosed within the chorion, while the tension at the surface is decreasing near the animal pole, the egg cortex on the vegetal side must still be adhering to the chorion because the cortical response has not yet taken place there. By the time the egg cortex at the vegetal pole detaches itself from the chorion with decreased tension, tension near the animal pole should have already begun to increase. If so, the egg cortex on the vegetal side must be pulled toward the animal pole and the transient shift of oil droplets toward the animal pole, mentioned in connection with Figure 3, becomes understandable. Stationary phase Within about 20 minutes after the completion of the cortical response, the naked egg bulges higher than before fertilization. This 20-minute period coincides with that of the stationary phase, so that it seems that oil droplets do not begin to move 1"4 YOST1I i SAKA1 until the tension at the surface reaches a certain level. Similarly, if a part of the yolk is sucked out from the egg about 15-20 minutes after fertilization, when oil droplets would begin to migrate under natural conditions, the egg is flattened and the droplets in the treated egg do not migrate until the egg rounds up again. In such eggs having lost a part of the \olk. the formation of the hlastodisc tends to he retarded and so does the accumulation of oil droplets at the vegetal pole. The recovery of the egg shape (recovery of the level of tension), therefore, seems to IK- essential for the initiation of the migration of oil droplets. These observations are of interest in connection with the fact that, in Brachydanio eggs, a protoplasmic movement inside tin- \olk and a counterstream in the protoplasmic coat begin only after the egg becomes exactly round (Roosen-Rtmge, 1938). However, no ex- planation is available concerning the manner in which a higher membrane tension and the bipolar segregation of the protoplasmic components are connected with one another. PART II. MOVKM KNT OF INJECTED OIL DROPLETS FOLLOWING ACTIVATION After analyzing the movement of the natural oil droplets, it is of interest to see how a droplet of oil foreign to the egg will move when it is introduced into the egg by injection. METHODS Salad oil (as a neutral oil; acid value (A.V.) - 0.22), liver oil (as an acidic oil; A.V. 0.52), and mineral oil (as a non-polar oil) were used as substances to be injected. To distinguish the injected oil droplet from the natural ones of the eggs, the oil to be injected was previously stained with Sudan III. By using a micro- manipulator, an oil droplet of a size similar to that of natural ones (20-70 p. in diameter) was injected into the cortical protoplasmic layer (cortex) of the un- fertilized eggs, either centrifuged or non-centrifuged, and of the fertilized eggs at the one-, two-, and 8-cell stages. When oil droplets are injected into the fertilized eggs, the chorion is previously removed by using the hatching enzyme of Oryzias (Sakai. l ( '0l ). Since the cortex of the unfertilized eggs is very thin, the tip of tin- injection needle sometimes misses it. If the oil happens to he injected into the yolk, the oil moves freely by gravity. If the oil is injected at too shallow a layer, the oil is apt to be squeezed out of the egg surface into the perivitelline space after the alveolar breakdown. As a result, successful injection can easily be determined. For measuring the movement of the injected oil droplet, the same procedure is applied as that which was used in I 'art I. RESULTS \\i> ( INCLUSION Hehai'ior <>\ the injected oil droplel The oil of Oryzins eggs is a kind of neutral oil because it is stained deeply with Sudan III and Sudan black, and also stained a pink color with Nile blue sulfate at about pH 7.0. Such a stainabilitv is the same as that of oil droplets of Onchdrynchus eggs (K. Yamamoto, 1 ( >58). OOPLASMIC SEGREGATION IN FISH EGG 195 To test another kind of neutral oil, salad oil is used. After the injection of salad oil, the eggs are fertilized or activated by pricking. Although some eggs are activated by the injection procedure itself, the behavior of the injected oil is much the same as that in the eggs activated after a successful injection in an inactivated condition. When injected at the equatorial region, the injected oil. on pricking, generally migrates toward the vegetal pole, fusing with the natural oil during the movement (Fig. 5). In fertilizable but slightly under-ripe eggs, merging of the natural oil droplets among themselves rarely occurs but even under such a circumstance, the injected oil droplets move to the pole side by side with the natural ones. Occa- sionally, the injected oil fails to move, probably owing to imperfection of injecting technique, in spite of the successful migration of natural oil droplets lying closer to the animal pole than the injected one. In such cases, natural droplets situated a FIGURE 5. Movement of oil droplet injected at the equatorial region of the unfertilized egg (side view). The egg is placed upside down to avoid the rotation of the egg caused by as- sembling oil droplets, (a) 20 minutes after fertilization; (b) about 40 minutes after fertilization; (c) one hour after fertilization. Injected oil has fused with the natural oil. on the animal half overtake the injected oil and pass it closely around its circum- ference. However, if the oil droplet migrates at all, it always migrates toward the vegetal pole, and never toward the animal pole. Quantitatively, too, the behavior of the injected oil corresponds well to that of the natural droplets as shown in Figure 6. The frequency of the migration is less when the oil is injected close to the animal pole than when injected at the equator. To clarify whether or not the behavior of the injected oil varies with its prop- erties, similar experiments were repeated by using liver oil, mineral oil and the oil of Oryzias eggs. These experiments give substantially the same results as that of the salad oil. Judging from the fact that the injected oil of Oryzias itself some- times fails to move, it is most likely that the failure is not due to the properties of the oil but to disturbance caused by the injection technique. Relationship between movement of protoplasm and oil droplets From the foregoing results, the oil droplets migrate irrespective of the nature of the oil itself. However, this still leaves the possibility open that the migration of the oil droplets is somehow coupled with the movement of the protoplasm. To make sure of this point, the following two conditions were tested : ( 1 ) weakly centrifuged YOSHI T. SAKAI eggs (100-200 g for about three minutes), with the natural oil droplets shifted to one side but leaving the protoplasm undisturbed. (2) strongly centrifuged eggs (900-1800 g for 10 minutes), with both oil and protoplasm localized at tin- opposite sides. In non-injected eggs, shifting of the natural oil by weak centrifugation does not interfere with ooplasmie segregation, regardless of the abnormal localization of -90 TIME AFTER FERTILIZATION (M IN) Fna'ki-; 6. Time courses of tlu- migration of inji-cti'd oil droplets in comparison \vitli the natural droplets. ( )rdinate : the value of ft, taking tin- equator as (I; abscissa: time after fertilization in minutes: closed circle: injected oil droplets: open circles: natural oil droplets; AI': animal pole; VI': vcjictal pole; KO : equator; arro\\ : fusion of oil droplets. the droplets after centrituging. In centrifuged eggs, the injection is made where the natural oil droplets arc no longer found, although protoplasm and cortical alveoli are still promt in the egg cortex. In spite of the absence of the natural oil droplets around the injected oil, it can migrate toward the vegetal pole all by itself. ' >n the other hand, by strong centrifugation, the protoplasm of the unfertili/ed egg can be shifted in the animal region and the oil is massed at the vegetal pole bv .orienting the egg by a capillary tube-. As the result, a blastodisc is formed at the OOPLASMIC SEGREGATION IN FISH EGG 197 centrifugal animal side where the protoplasm has already collected. The oil is injected at the equatorial region where little protoplasm is found. Under these conditions, the injected oil is fixed at the injected point and never migrates toward the vegetal pole within the observation period of three hours. To further confirm the idea that the migration of oil droplets is caused by the movement of the protoplasm, the oil is injected near the equator of the egg at the one-, two- and 8-cell stages in which the protoplasmic segregation has almost been completed. The injected oil droplets never migrate toward the vegetal pole. The relationship between oil and protoplasm is also pointed out by the following results. When an egg is forced into a capillary, both the migration of oil droplets and the formation of the blastodisc are much delayed. Furthermore, if more than one protoplasmic accumulation is induced by polyspermy or strong prickings, such protoplasmic accumulations are always accompanied by the migration of oil droplets toward the opposite side of each accumulation (Sakai, 1964a). Further, the experiments on partial activation indicate that the oil migration does take place only in the activated half (Sakai, 1964b). If the migration of the protoplasm has a leading role over the movement of natural oil droplets, the elimination of the oil droplets is expected to have no influence on the movement of the remaining protoplasm. In the eggs weakly centrifuged at 100-200 y for about 5 minutes just after the fertilization, the cortex ^protrudes where the oil is forced to gather. Such a mass of oil can be sucked out with a micropipette. As in Nereis egg fragments observed by Costello (1940), yet the migration of the protoplasm can still occur and form the blastodisc. On the other hand, careful observation reveals that the protoplasmic movement always precedes that of the oil droplets, that is, by the end of the stationary phase, a small amount of protoplasm has already begun to accumulate at the animal pole, slightly flattening the yolk surface under it. Considering the above-mentioned results in connection with this observation, it will be concluded that the migration of oil droplets is a consequence of the movement of protoplasm toward the animal pole. The author is indebted to Professor K. Dan for his invaluable advice. The author's thanks are also due to Dr. M. Yoneda for his kind help in the calculations. SUMMARY The movement of oil droplets in Oryzias eggs, natural and artificially injected, was analyzed during ooplasmic segregation, (a) During 2-4 minutes alter fertili- zation, natural oil droplets are shifted transiently toward the animal pole, followed by a stationary phase of about 20 minutes. After this phase, all of the oil droplets coming either from the animal or from the vegetal side assemble at about 60 below the equator as a ring and later reach the vegetal pole. The migration is faster in droplets coming greater distances than in those coming shorter distances, (b) The pattern of the migration of injected oil droplets is the same as that of the natural ones, irrespective of their nature. The migration is possible in weakly centrifuged eggs in which the protoplasm remains undisturbed in the cortex. 198 YOSHI T. SAKAI However, injected oil droplet. s no longer move after shifting of the protoplasm 1>\ strong centrifugation or after the completion of ooplasmic segregation. LITERATURE CITED COSTKU.II, 1). I'., 1'MO. Tlu- iVrtili/ahility of nucleated and non-nucleated fragments of cen- trifugcd \ereis eggs. ./. .I/or/ 1 /;., 66: 99-114. COSTKI.I.O, I). I'., l')4S. Ooplasiiiic MUD Cation in relation to differentiation. Ann. Xcw York Acad. Sri., 49: 663-683. LEWIS, \\'. H., 1949. Superficial gel layers of cells and eggs and their role in early develop- ment. Ann. I nst. liiuloiiiti. Me.rico, 20: 1-14. Roi>sK.\-Rr.\i;K. E. C., 1938. On the early development bipolar differentiation and cleavage of the zebratish, Hrtieliyddiiio rerio. Riol. Bull., 75: 119-133. SAKAI, Y. T., 1961. Method for removal of chorion and fertilization of the naked egg in Oryzius hi fifes. Embryologia, 5: 357-368. SAKAI, V. T., l l '64a. Studies on the ooplasmic segregation in the egg of the fish, Oryzlas Infixes. I. Ooplasmic segregation in egg fragments. Einlvynlin/ui. 8: 129-134. SAKAI. Y. T., 19641). Studies on the ooplasmic segregation in the egg of the fish, Oryzius latipcs. II. Ooplasmic segregation of the partially activated egg. Embryologia, 8: 135-145. Si'KK, T., 1933. Die bipolare Differenzierung des Protoplasmas des Teleosteer-Eies und ihre luitstehnng. I'rotophtsma, 18: 497-545. Tiio.Moi'ouLOS, A., 1 ( )53. Sur 1'oeuf de 1'Epinoche (Gasterosteus ticnlctitiis L.). Hull. Sac. Zool. France, 78: 142-149. YAMAMOTO, K., 1958. N'itellogenesis in fish eggs (in Japanese). S\mposia Cell Chan., 8: 119-131. YAMAMOTO, T., 1940. The change in volume of the fish egg at fertilization. Proc. /;;;/>. Acud. (Tokyo), 16: 482-485. GROWTH AND SURVIVAL OF POSTLARVAL PENAEUS AZTECUS UNDER CONTROLLED CONDITIONS OF TEMPERATURE AND SALINITY * ZOULA P. ZEIX-ELDIX AXD DAVID V. ALDRICH Bureau oj Commercial Fisheries, Galveston, Texas Temperature and salinity may be considered among the most important abiotic factors influencing the growth and survival of much of the estuarine fauna. They are of particular significance to those organisms that spend certain portions of their life cycle in the open sea where both factors are relatively stable, and other portions in the estuarine areas where both temperature and salinity may change drastically. Although temperature is generally thought to overshadow salinity in its effects on migratory organisms, salinity, probably through its osmotic effects, also plays a part in limiting some organisms to specific environments. Several investigators have attemped to evaluate the importance of temperature and salinity to penaeid shrimp of the Gulf of Mexico, but ecological questions con- cerning these factors remain unanswered. Although field studies have dealt with the relationship of shrimp to salinity, the conclusions reached have differed widely enough to warrant further investigation. The interpretation of observations on salinity and shrimp abundance in nature is made difficult by changes in other environmental factors, some of which frequently vary with salinity. Such factors include temperature, light, substrate, food supply, cover and pollution. For this reason, controlled-environment studies in the laboratory were employed in the present work. In an earlier study, Zein-Eldin (1963) determined that under conditions of constant temperature and somewhat restricted food supply, grooved Pcnacits post- larvae - survived and grew over a wide range of salinity (2-40/e). However, it has been suggested that in other migratory Crustacea, notably in the European shrimp, Crangon crangon (Broekema, 1941), as well as in juvenile and adult brown and pink shrimp, Penaens aztccus and P. diioranun, respectively (\\illiains, i960), temperature can influence tolerance to salinity. Thus, further studies were designed to test the combined effects of temperature and salinity on the survival and growth of postlarval brown shrimp. MATERIALS AND METHODS The work was of two types, 24-hour survival studies and a 28-day growth experiment. For all work, postlarval brown shrimp of approximately 12 mm. rostrum-telson length were seined from the Gulf of Mexico surf at the entrance to Galveston Bay. The animals were held in the laboratory in aerated water of ap- 1 Contribution No. 205, Bureau of Commercial Fisheries Hi<)1<>ical Laboratory, Galveston, Texas. 2 As denned by Renfro (1964). 199 200 ZOULA P. XKIX-ELDIN AND DAVID V. ALDRICH proximately 25',, and 25 ('. for at least 24 hours prior to use. Few mortalities occurred during this preliminary holding period. The fir.M ohjirti\-c was to ohtain a rapid, crude estimate of postlarval tolerance to salinity and temperature in order to provide guidelines for the more detailed and sensitive growth study to follow. Accordingly, we selected short-term survival as a rough index suited to our needs. To determine tin- short-term tolerance of brown shrimp to salinity and tem- perature, we exposed groups of experimental shrimp to different levels of the two factors for 24 hours. The test levels were chosen to include and extend above and below the ranges of salinity and temperature at which large numbers of postlarvae have been observed in nature (Bearden, 1'Xil ; Williams. 1955; Baxter, un- published ). Temperature control of 0.5 C. was maintained by B.( ).D.-type incubators. Salinity changes were effected by replacing portions of water in the test containers with equal volumes of either distilled water or evaporation-concentrated sea water. Salinity was determined by hydrometer and reported to the nearest part per thousand. Four series of 24-hour survival experiments were carried out with groups of 5 to 30 animals as described below. Series 1, 2 and 4 had an initial salinity of 2425',, and an initial temperature of 24 to 2(> C.. matching conditions of the holding aquaria. Initial salinity in Series 3 was 40'u, equal to the unusually high level at which animals for that series were collected. Following introduction of the shrimp into the vigorously aerated experimental containers, stepwise changes in both temperature and salinity (0 to 8 steps, depending on the magnitude of change involved) were made over a 10- to 12-hour period, to reach the desired conditions. The attainment of these conditions marked the beginning of the 24-hour test period. At the end of that time, the beakers were removed from the incubators and the live and dead postlarvae counted. Failure to show either spontaneous or probe- induced activity upon return to room temperature was considered indicative of death. No food was provided during the experiment. Previous observations of postlarvae in the laboratory had indicated that failure to keep them under water mechanically could lead to considerable mortality, due to their jumping activity. This type of loss was avoided during the first two series by restraining each group of animals in a one-liter beaker whose mouth was filled with a stemless funnel 4 inches in diameter. When the 1 beaker was tilled with water, all air space .accessible to the shrimp was eliminated, thereby preventing the animals from escaping the vessel or adhering to its drv surfaces. Aeration was provided by means of an air stone attached to , :i (; -inch ( ).l). Tygon tubing lifted through the hole in the funnel. In the first two series, we employed only live shrimp per group, hoping thus to reduce cannibalism. Although losses caused by escape from the water were success- fully avoided, test results indicated that cannibalism occurred at intermediate and higher temperatures where the number ot survivors plus the number of dead animals remaining per group frequently totaled less than the original number of shrimp (Table I ). In such cases, we attempted to discriminate between deaths due to cannibalism and mortalities attributable to salimt\ and temperature bv arbitrarilv assuming that salinity-temperature combinations causing the rapid death of some experimental shrimp were sufficiently severe to inhibit feeding, including cannibal- GROWTH AND SURVIVAL OF P. AZTECUS 201 g S ' *. "- ^4 ti i i .s s to s Jj K S w ?s Ci 10 ^ s <0 a, & -0 - CO CN CN CO X >c -H CO * CO O 10 o CO CO CO IO !- CO CN -C 10 -t CO 5 o (H o ^ ^O - -1 -H 0- - CO - o * CO -t CN -t t - -f -* o 10 Ov CO CO w * ^ >o s 3- O 00 CN 00 * CO C 10 c E? *t o CO - c -f o * 10 O sC o CO CN ro -N CO CN -t ^ o 9i co O CO O o o ^ 10 O 00 "t ON ^O CO CO -f 10 * 10 o IO Q p/5 CO ^H IO IO O on c ,0 <N "> CN 10 o S * 10 o 8g o CN CN CO 3 ( -t c 00 TC ,, e o o __, IO CO O -t -t o i^. 00 rd C ^ 10 o 00 10 o 00 o jj CO CO to -t 10 o _). 10 o -f o Q CO CO CO W 10 ^ 10 o 10 ^, 10 O 10 o ~* CN ^ CN rt CN ~ C -t O CO -N ^ - Tf o 10 ^ 00 5 00 CN 9 o o t -H 00 * - [^ o o O CO CO CO ~^ CN 1O O -t CO 10 O 'C CO o >o CN rt - I, fO 10 o t^ -t 10 o I- 10 o CN CN CN *^ 00 - * a CN co O vO co O IO .0 o 10 VC o U U U cJ U O o o O v ^~. * OJ ^ * 11 ^-* aj ^ UJ ^^ a ~ a il F! a C3 ^~ to i' o rt "^ i i? ' P cd ^^ a) ^ CO P H i^ 5 ll 11 1 1 > 1 u II 1 OJ H en 5 H en f- en en H en tn 7 d^ C ~^s 7 7 52 = 0,0 Q, ~ ES 10 10 O O O 'u 60 7. i w C 6 CN CO ^ | /-. o 3 O O OJ so c c 60 O c s I o " a -3 s n ^ 11 I H * 202 ZOULA I'. ZEIN-KI.DIX \.\l) DAVID V. M.DRHll ism. among the- survivors, High rates of penaeid activity, including movement, feeding, and molting, have heen observed at temperatures of 25 and 32 C'. in this laboratory. Such activities favor cannibalism among shrimp under relatively crowded experimental conditions. ( >n this hasis, we counted as mortalities only those dead animals visibly present at the end of each 24-hour experimental period. To test this assumption. \ve required data unaffected by cannibalism. These were obtained in Series 3 by confining each animal within a 11-inch length of 14-mm. I'vrex tubing, both ends of which were covered with cotton gauze held in place with small rubber bands. While permitting contact between the animal and its experi- mental aquatic environment, this procedure prevented "jump-out" losses and made physical contact between shrimp impossible. Ten postlarvae thus isolated were placed in each test beaker and the experimental conditions established as before. The survival results agreed well with those of the two earlier series as interpreted above, tending to substantiate our assumption regarding the effect of cannibalism. TABU: 1 1 Schedule nf salinity and temperature changes [initial salinity and temper/it lire 26%o and 23 C., respectively"] Klapsed time (hr.) 1 v-iu-d salinity (%o) 1 >rsired temperature ( C.) 2 5 15 25 35 1 1 18 25 30 Actual salinity Actual temperature 2 20 20 20 25 25 23 23 23 26 8 15 15 15 25 30 19 22 24 30 24 10 1(1 15 25 35 17 19 25 33 36 5 5 15 25 35 12 18 25 33 48 2 5 15 25 35 11 18 25 32 In a fourth series, further survival data were sought at temperature-salinity com- binations which seemed to be near the extremes of postlarval tolerance, as suggested by results of the three previous series (Table I). In this series the importance of acclimation was also estimated. Fach set of experimental conditions was duplicated in two two-liter beakers, one for shrimp acclimated as usual, the other for animals which were transferred directly from the holding tank to the extreme salinity and temperature levels to be tested. Thirty individually confined postlarvae were held in each beaker, and 24-hour survival determined as before. For the growth study. 46 liters of brackish water and 100 animals were placed in each of twenty 15-gal. aquaria. Filtration, aeration, and confinement were accomplished as previously described (Zein-Eldin, 1963). .Five aquaria were placed in each of tour constant-temperature rooms. The experimental temperatures were changed from the initial 23 C. to 11. 18, 25". or 32 C. Water tem- perature, although 0.5 C. in a given aquarium, varied as much as 1 C. among aquaria in a single room. The initial salinity of 23',, was simultaneously adjusted stepwise with temperature, to final levels of 2',,. 5',,, 15',,, 25',,, or 35',, (Table J I ) . Fach lank was continuously illuminated bv two 40-w. fluorescent lamps. GROWTH AND SURVIVAL OF P. AZTECUS 203 Postlarvae were fed live brine shrimp (Arteuiia} nauplii throughout the growth experiment. The nauplii in a 0.1-ml. sample of brine shrimp in water were counted to estimate number per unit volume, and the volume of food recorded at each feeding of the postlarvae. Artcmia nauplii were filtered and washed with distilled water before their addition to the tanks, in order to avoid increases in experi- mental salinity levels. Live brine shrimp nauplii were present in excess in all aquaria during the first 24 days of the experiment. During the last four days at 32 C., however, the shrimp had grown to such a size that maintaining an excess food supply became almost impossible, even though 400,000 to 500,000 nauplii per tank (a minimum of 9000 to 10,000 per experimental animal) were supplied per day. TABLE III Cumulative inorluli-ty [only observed deaths arc included'] Elapsed Temperature time (C.) (days) Salinity (% ) 2 32 5 15 25 35 2 25 5 15 25 35 2 5 18 15 25 35 2 5 11 15 25 35 1 5 1 1 2 000 2 41 25 16 2 2 2 4 2 3 44 25 16 6 13 3 77 2 4 45 25 17 7 I) 17 3 93 5 5 45 25 17 7 19 3 97 12 6 45 25 17 7 19 3 (J 97 12 7 45 25 17 7 19 3 97 22 8 45 25 17 7 19 3 97 25 I) 9 45 25 17 7 19 3 (1 97 32 10 45 25 17 7 19 3 97 37 (I 11 45 25 17 7 24 3 97 41 12 45 25 17 7 26 4 97 45 13 45 25 17 7 27 4 97 50 14 45 25 17 7 {) I) 27 4 97 55 17 45 25 17 7 29 4 97 60 (1 18 45 25 18 7 1) 31 4 I) 97 60 19 45 25 18 7 45 4 97 60 000 20 46 25 18 7 23 57 4 97 63 21 46 25 18 7 39 I) 58 5 97 63 22 46 25 18 7 50 58 5 97 63 24 46 25 18 7 55 58 5 97 66 28 46 25 18 7 2 55 58 5 97 67 004 No. of animals removed for measurement 25 30 35 50 50 40 50 50 50 50 36 50 50 50 50 30 50 50 50 No. escaped 2 4 4 3 1 2 2 2 Observed survivors 15 22 25 29 47 43 43 50 49 41 46 48 49 49 46 43 Unobserved deaths 12 23 22 14 1 1 3 4 1 5 2 2 1 3 3 1 4 3 Per cent survival 21 31 38 58 94 93 91 100 98 85 96 100 98 98 92 86 At approximately 5-day intervals, 10 animals were removed from each aquarium. These included both the largest and smallest specimens, and eight collected at random. The animals were individually measured to the nearest 0.5 mm., blotted dry, weighed to the nearest 0.1 mg. with a Mettler HIS analytical balance, and pre- served. At the termination of the experiment, all remaining animals were similarly treated. The final per cent survival was determined by comparing the total number of shrimp remaining at the close of the experiment to the number that theoretically should have been present (original number less those that had been removed for sampling and a few that had escaped ) . The unobserved deaths recorded in Table III were animals not accounted for either as survivors, observed deaths, or those sampled for measurement. On the assumption that an individual Artemia nauplius weighs an average of 7.1 f^g. (D. Godwin, unpublished), we estimated conversion efficiency by compar- ing the calculated wet weight of the brine shrimp that were fed with the weight 204 ZOU \ I 1 . /I.IX-EI.DIX AN'D DAVID V. ALDRICII gain of the- surviving pcnacids. Determinations were made only for those tempera- ture' and salinity combinations at which survival was S5'/V or greater. Although the design of the experiment was similar to that of Costlow, Bookhout and Monroe (l l ><>0, l''(>2) in studies of larval crah survival, we did not use the -tatiMical methods which they employed. The fitted-surface method of Box and Youle ( 1 ( '55 i has proved valuable in industrial applications of physical and chemical interactions \\hose principles are sufficiently well defined to permit relatively safe 40, Shrimp per Series Group X = I 5 0=2 5 El = 3 10 O=4 30 40 45 IMCCKK 1. IVr cent survival of /'. uztccus postlarvac after 24 honi> at indicated K-vrK <>t salinity and temperature. extrapolation trom a limited number of experimental observations. However, the complex nature of biological responses to temperature and salinity renders such extrapolation extremely speculative. In the present study, we have tested a group of temperature-salinity combinations which represents a relatively large range of levels for each factor. ( )ur interpretations of the results exclude extrapolation. l\l Si I. IS VND DISCUSSION Short-term s The excellent survival of postlarvae for periods of 24 hours under most of the experimental conditions suggested a broad /.one of short-term tolerance to both GROWTH AND SURVIVAL OF P. AZTECUS 205 salinity and temperature (Table I). The animals were quite euryhaline, especially at 25 and about 30 C, although a marked reduction in tolerance to salinity levels below 10',, was demonstrated at 7 and 15 C. (Fig. 1). A general reduction in survival near 35 C., regardless of salinity, suggests a strong tempera- ture effect. The absolute limiting ( maximum j temperature for P. aztccits is probably only slightly above 35 C. 35r- 30 o o 9 k- 25 20 - v I ' 5 10 21 1 1 1 1 '////,- 80-100% Survival for 24 Hours ' 28 Days I 1 1 10 30 35 40 15 20 25 Salinity (%o) FIGURE 2. Long- and short-term survival of P. azteciis at indicated levels of salinity and temperature. Numbers indicate 28-day survival in per cent. The effect of acclimation in extending ranges of postlarval tolerance is clearly shown in the results of the fourth series. In each of the four combinations of temperature and salinity, gradually changed conditions permitted better survival than did sudden changes (Table I). This effect was considerably more marked at 10 than at 35 C. 28-Day sitri'k'ol The survival of postlarvae in the 2X-day experiment further confirmed this wide zone of tolerance to salinity and temperature. Although the per cent survival for 28 days was somewhat lower than that observed for only 24 hours, in most cases the results were much the same (Fig. 2). There is some suggestion of greater long-term survival for animals at low temperature and low salinity than 200 ZOTI.A 1'. XKIX ELDIN \D DAVID V. ALDRICH 600 n D A A >32 C * a * 100- . - a X * ' o A o-2%o g 0-5 % * 10- 4 = 5H 7> a X - 1 5 %o -25% l i i 1 1 1 ) 600- 5 > } 25C. - i 100- 8 o s s - X - 2 M o ; 18 C. 8 A . / A o 10- -< 5- C 1 , 4--t--t r I 5 !) i .0 ) 5 10 15 20 25 3 Time (days) FlGURI .\ (irii\vtli nl yoiin.L: /'. </:;ViY/i.v at iinlirak'<l levels ,,)' tempi-nitim 1 ami salinity. GROWTH AND SURVIVAL OF P. AZTECUS 207 for those exposed only 24 hours. This apparently paradoxical situation is probably related to the longer acclimation period employed in the 28-day study. Survival was markedly reduced at the highest temperature (32C. ) at all salinities tested except 35% . Much of the accountable mortality at this tem- perature occurred during the first four days (Table III ) and \vas presumably the result of the immediate stress caused by the changes in environment. However, the stress of salinity acclimation would not seem to explain the poorer survival observed at 25 f / C c (very near the initial salinity ) than at 35 c / ( ,. The relatively large numbers of unobserved deaths occurring at 32 C. and 2'/ f .,$'/< f , IS'/ic and
25%c (Table III) suggest two other possible causes of mortality the experi-
mental temperature per sc, and increased cannibalism associated with high tem-
peratures (as noted above in Series 1 and 2 of the 24-hour studies). It is possible
that at 32 C. the one-month period of exposure in the growth experiment elicited
long-term temperature effects which could not be manifested in the relatively short
duration of the 24-hour studies.
TABLE IV
Increase in mean length (nun.'] of P. azteciis surviving 28 days
at indicated levels of temperature and salinity
Salinity (% )
Temperature
( C.)
2
5
15
25
35
32
2.5.4
28.9
19.0
32.0
25.8
25
21.9
24.4
22.3
22.6
18
6.3
6.5
7.4
7.6
11
0.5
0.5
0.4
Mortalities occurring at other temperatures were limited to the lowest salinitie.s.
with stress due to reduced salinity and temperature being sufficient to kill all the
animals at 2% and 11 C. in only 5 days (Table III). The mortalities observed at
5 c /co and 11 C., as well as those at 2% and 18 C., probably reflect the cumulative
effects of stress, since deaths occurred continuously throughout the course of the
experiment. At 25 C. and 2%-c, however, all observed deaths occurred during a
four-day period late in the experiment. Although the initial cause of this mortality
is not known, later deaths (on the 21st through the 24th day) were probably
due to fouling of water, since brine shrimp were also dying. Furthermore, an
earlier experiment (Zein-Eldin, 1963) had indicated that P. ac teens postlarvae
survive well under these conditions.
Grou'f/i
Differences in rate of growth were more closely related to temperature than to
salinity (Fig. 3). The relative effects of the two factors may IK- readily determined
by comparing the magnitude of growth differences associated with variation in
salinity (columns) with that due to variation in temperature (rows) (Table IV).
Differences in mean length between temperature groups were detectable as early as
the first sampling period (5 days) and increased in magnitude during the experi-
208
zori.A p. XKIX Ki.nix \xn DAVID v. ALDRICH
mental period (Fig. 4). Both length and weight increased much more rapidly
at 32" and 25 C. than at lower temperatures. The maximum increase in size was
>1 'served at 32 and 25',,, conditions under which one animal grew to 50 mm. and
(| (>2 mg., a more than four-fold increase in length and a weight increase of 150-fold
(Tahle V). The great variation in size noted earlier (Zein-Eldin, 1963) was also
observed in this experiment, with differences in length between smallest and largest
45 i-
32 C.
-.1 1 1
1 1
10
5 10 15 20 25 30
Time (days)
IMGCRK 4. (innvtli of younn" /'. aztecus at various temperatures (salinity: 25',, ).
animals ranging from 13 to 25.5 mm. in the various salinities at 25 and 32 C.
n'able V). Almost no growth was detected at 11 C., although survival was
good at salinities of 15',, and above. \Vith the exception of 32 C. and correspond-
ing salinity levels of 25',', and below, where mortality more than offset the rapid
growth rate (Tables IV and VI), the gain in total weight of the survivors was
comparable within a temperature. However, this gain increased approximately
10-fold within each level of salinity between II and IS" C., and only slightly less
between 18 and 25 C. (Table VI).
GROWTH AND SURVIVAL OF P. AZTECUS
209
TABU-: V
Mean size mid grind h rate of growth-experiment survivors, including 10 anninls
sampled a I 28 days and shown in Table I'll. S /'.:< range gircH in parentheses.
Initial ice/ght and length were 6.1 nig. and 12. 1 nun., respectively
Temperature
and salinity
Number of
survivors
Weight (mg.)
Length (mm.)
Increase in length per
day (mm. /day)
32 C.
i' it
15
340.6 (157.7-735.1)
34.8 (27.5-47.5)
0.81 (0.55-1.26)
>'
22
447.6 (241.0-667.6)
39.6 (33.0-46.0)
0.98 (0.75-1.21)
15&
25
240.2 ( 35.2-542.0)
31.0 (17.0-42.5)
0.68 (0.18-1.09)
25%c
29
610.8 (309.0-961.9)
43.1 (36.0-50.0)
1.11 (0.85-1.35)
35 %c
47
423.7 (164.7-753.6)
38.3 (28.5-46.5)
0.94 (0.59-1.23)
25 C.
5%o
43
274.0 (115.3-482.0)
33.9 (25.0-41.5)
0.77 (0.46-1.05)
15%o
43
375.3 (163.8-681.1)
37.4 (29.0-46.5)
0.90 (0.60-1.23)
25%
50
313.8 (101.4-538.0)
35.2 (24.0-44.0)
0.82 (0.42-1.14)
35 %o
49
291.0 (108.0-605.7)
34.4 (24.5-43.0)
0.80 (0.44-1.10)
18 C.
5%
41
33.9 (18.0- 56.2)
18.3 (14.0-21.5)
0.20 (0.08-0.34)
15%o
46
43.7 (15.3- 77.7)
19.1 (14.5-23.0)
0.25 (0.09-0.39)
25%
48
52.8 (15.0-101.4)
20.1 (14.0-25.0)
0.29 (0.08-0.46)
35%
49
35.2 (17.7- 62.7)
18.3 (14.5-22.0)
0.22 (0.09-0.35)
11 C.
15&
49
8.7 (5.2-13.1)
12.6 (11.0-14.0)
0.03 (0-0.08)
25%o
46
8.8 (6.4-10.8)
12.7 (11.5-14.0)
0.02 (0-0.08)
35%
43
7.6 (5.5- 9.7)
12.4 (11.0-13.0,
0.01 (0-0.08)
Growth rate based only upon the steepest portions of the growth curves (i.e.,
between the 10th and 28th days) approached a value of 1.4 mm. per day at 32
C. and 1.1 mm. per day at 25 C., as against the lower values of 1.1 mm. per day
at 32 and 0.8 mm. per day at 25 C. over the entire experimental period (Fig. 4,
Table VII). Although the mean growth rates reported here (Table V) for both
25 and 32 C. exceed the maximum of 0.56 mm. per day which Pearson (1939)
reported for laboratory-held postlarvae of P. brasilicnsis (probably P. aztccus*),
and the maximum of 1.35 mm. per day far exceeds his value, these rates do not
TABU- VI
Increase in total weight (g.) of P. azteciis surviving 28 days at indicated levels
of temperature and salinity. Food conversion efficiency (%) indicated
in parentheses where survival was 85% or greater
Temperature
Salinity (% )
(C.)
2
5
15
25
35
32
4.7
9.6
5.8
17.5
19.6 (37)
25
11.5 (43)
15.9 (53)
15.4 (46)
14.0 (43)
18
1.2 (32)
1.7 (33)
2.2 (40)
1.6 (34)
11
0.1 (12)
0.1 (14)
0.1 (5)
210 ZOULA P. /KIN' ELDIN AXD DAVID V. ALDRICH
approach that of postlarval white shrini]), /'. sctijenis, which grew an average of 2.1
nun. per clay in pond experiments conducted hy Johnson and Fielding (1956).
A similarly low rate of growth for aquarium-held Mctapcnaciis inastcrsii, which
ranged in carapace length from 1. to 7.0 mm., has been reported by Dall (195Si.
Laboratory animals grew only 10 mm. in total length per month at 24 to 28 C.,
as against a natural growth rate of 20 to 30 mm. per month.
Growth of our laboratory-held P. aztccits postlarvae likewise only approached
that of slightly larger animals in the field. Yiosca (1920) estimated a growth
rate of approximately 25 mm. per month for P. sctijenis in the length range 30
to 150 mm., while Gunter ( r>50) observed a rate of 25 to 40 mm. per month for the
same species growing from 2S to 100 mm. Extrapolation of Lindner and Ander-
son's (1956) growth curve for white shrimp gives a rate of 1.50 mm. per day for
shrimp between 20 and (>5 mm. in length. \Yilliams (1955) determined a rate
of 1.7 mm. per day for /'. nztccits growing from 37 to 102 mm., a rate also
estimated by St. Amant, Corkum and Broom (1963) for 51- to 125-mm. specimens
of this species. It must be noted, however, that these estimates were for shrimp
at the upper end of the size ranges encountered in the studies described here.
Although the studies of conversion efficiency were necessarily crude, the
resulting data indicated that the most efficient utilization of food occurred at 25
C. (Table VI). Because of the high mortality, no efficiencies could be calculated
for shrimp held at 32 C. in salinities of 25%c and lower. The conversion values
should be considered maximal at the highest temperatures since some cannibalism
probably occurred. However, efficiencies for the animals held at 11 C. are
probably low since it was apparent that much of the food provided was not eaten.
At this low temperature, the postlarvae were generally inactive, resting most of
the time on the bottom.
Johnson and Fielding (195h), studying P. sctifcnts in aquaria during August
(temperature not stated), found a mean food-conversion efficiency of 19% for
juveniles (mean weight 0.9 to 2.1 g.) held one week at 18.5^V. as against an
efficiency of 24% for juveniles (mean weight 0.7 to 2.1 g. ) held one week at 34%c.
All animals were fed at a rate of 10% of the initial body weight per day, a rate less
than that provided in our experiments. The lower efficiencies determined by
Johnson and Fielding may be due, in part, to the larger size of the animals held,
since it has been shown in fishes ( Kinne, 19(>0 ) that conversion efficiency decreases
with increasing size. Furthermore, Johnson and Fielding obtained the maximum
efficiency of 50% from a group of animals of 0.7 g. mean weight held at 34%o.
This value compares favorably with those reported here for brown shrimp of
mean weight 0.3 g. and less, and would indicate that rapidly growing young
shrimp require 2 to 4 g. of utilizable food to produce 1 g. of tissue.
The decrease in growth rate of animals held at 32 C. and 15'/r is unexplainable.
This group of animals consumed less food during the latter days of the experi-
ment, even though excess food was present. If this decreased growth represented
a long-term effect of the combined stresses of lowered salinity and increased tem-
perature, it is strange that such a decrease did not occur among groups held at even
IOVUT salinities at this temperature. Interpretation of the combined effects of
lower salinity with 32 C. on growth was complicated hv the high rates of mor-
tality among these Croups.
GROWTH AND SURVIVAL OF P. AZTECUS
211
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212 XOl'l. A P. ZEIN ELDIN ^ND DAVID V. AI.DRICH
Biological and ecological implications
Commercially important Xorth American shrimp of the genus PCIKICHS spawn
at sea. As shown for /'. sc/il'rnis, the larvae develop in the open sea, migrate
into the estuarine areas as postlarvae. remain in the less saline estuaries until they
approach maturity, and then return to the sea (Weymouth, Lindner and Ander-
son, 1 ( <33; Rurkenroad, 1 ( >34; Pearson, 1939). Various studies in the field have
suggested that postlarval and juvenile J'cinicns are associated with low salinities
characteristic of the estuary, and that postlarvae require the lowest salinity for
growth and survival ( ( lunter, 1 ( H5, 1950; Pearse and Gunter, 1957). Lindner
and Anderson ( 1 ( >50) concluded, however, that size of white shrimp (juveniles and
suhadults ) seemed more closely related to locale than to salinity. Gunter, Christmas
and Killehrew (1 ( >04) have recently presented additional field data indicating
differences in the natural di.strihutions, with respect to salinity, of the three com-
mercial species, P. aztccus, I', dnorannn, and P. sctijcnts. In so doing, these
authors have made certain assumptions. For example (p. 1S4): "If salinity
meant nothing to these animals they would he evenly distributed relatively over
the whole range, if food were availahle. The general food hahits of shrimp are
still largely unknown, hut all indications are they are omnivorous feeders, and shrimp
do find food over the full salinity range up to pure sea water, although the food
douhtless changes with si/e." The fact that shrimp do apparently eat a variety of
food does not, however, indicate that all such foods are of comparable nutritive
value (Williams, 195 ( >; Zein-Eldin, 1903). Furthermore, there is no evidence that
food is equally availahle throughout the salinity range occupied by shrimp in
nature. Onlv in a previous study (Zein-Fldin, 19O3) and in the work reported
here, has food been equally available to all animals regardless of salinity. The
24-hour survival experiments, as well as the growth study, indicated that for P.
aztccits postlarvae, only extreme salinity conditions influence growth and survival.
Even normal oceanic salinity is not sufficient to interfere with postlarval brown
shrimp growth and survival when other factors (temperature, food supply, pre-
dation, oxygen, light, pollution, etc.) are kept relatively constant. In view of our
results, we suggest that other factors, such as food or cover (which may them-
selves require relativelv narrow salinitv ranges), are of greater importance than
salinitv /vr ,sv in determining distribution, growth, and survival of these animals.
In the present studies, both the survival and the growth data indicated that
wide ranges of salinity and temperature were well tolerated by postlarval brown
>hrimp. The combination ot low salinitv and low temperature, however, was not
favorable, either for survival or growth. That P. aztccns can withstand extreme
conditions of both factors has been demonstrated in the Held as well, although
published records have been largelv limited to occurrences of juvenile and adult
forms (Gunter. I'bO). Hearden (l ( '0l), who found postlarval brown shrimp
at temperatures as low as f>.5" ( '.. noted a marked decrease in their abundance
following the sudden cold spell which resulted in this low-temperature value.
Ken fro and Baxter (unpublished) have reported live postlarvae at 12 C. and
31.0',, as well as at 2 C. and 30.5',,. supporting our laboratorv evidence that low
temperatures can be survived when salinities are sufficiently high. Comparable
data of postlarval occurrence in low-salinity areas are not yet available. Brown
shrimp ( si/.e not stated ) have also been reported in salinities as low as 0.8%e
r.RCWTII AND SURVIVAL OK 1'. AZTECUS
21.S
(Gunter and Shell, 1958) in Louisiana, while Guntcr and Hall (1963) report a
34- and a 38-mm. specimen at 0.22/^r in the St. Lucie estuary in Florida. No tem-
peratures were reported with the latter data, however. It must be noted, neverthe-
less, that St. Amant, Corkum and Broom (1963) reported maximal spring abund-
ance of postlarval brown shrimp in Louisiana bays only after water temperatures
consistently exceeded 20 C.
35r-
30
25
o
o
- 20
O)
l_
3
-t~
O
IH
o>
15
10
23.4 28.9
19.0
32.0
22.6
0.4
10 15 20
Salinity (% )
25
30
35
FIGURE 5. Growth and survival of young P. aztccns held 28 days at indicated levels of
temperature and salinity. Numbers indicate increase in mean length (mm.). Hatched zone
indicates 80-100% survival.
The temperature range permitting growth is more limited than the range for
survival (Fig. 5). Our laboratory studies have demonstrated that growth can
occur over a wide range of salinity at temperatures of 25 C. and above, and suggest
that the effect of temperature upon the rate of growth increases rapidly with
temperature between 11 and 25 C. (Fig. 6). This effect of temperature has
been confirmed in more recent experiments in which we observed growth at a
greater number of temperature levels between 15 and 35 C. than tested here.
The greatest growth differential per 7 C. was observed between the 18 and
25 C. levels. This difference may well explain the observation of St. Amant,
Corkum and Broom (1963, p. 25) that "metamorphosis of postlarvae into rapidly
growing juveniles occurs suddenly after water temperature exceeds 20 C." Above
25 C., increasing temperature has less effect upon growth. The recent experiments
214
ZOULA r. ZEIN KI.DIX AND DAVID V. ALDRICH
referred to above indicate that grouth is maximal at 30 to 32.5 C. This result,
coupled with the increased mortality at 32 C. suggests that such a temperature
Condition, although promoting rapid growth in some individuals, may be above the
optimum temperature for long-term growth and survival of P. aztecns postlarvae.
The laboratory evidence suggests that normal winter temperatures render the
brackish bay systems unfavorable for both survival and growth of brown shrimp
postlarvae, whereas almost any salinity will provide a favorable environment at
normal summer temperatures. Thus, the pattern of tolerance to salinity and tem-
perature observed in the laboratory may explain the seasonal distribution of P.
l.2 r
15 20
Temperature (C.)
25
30
35
FiGt'RK 6. Effect 'if temperature on the laboratory growth rate of young /'. aztccns (salinity :
2r',, ; length <>i' experiment : 2X days; initial length of experimental shrimp: 12.1 nun.).
(tztccits in much the same manner as described by Hroekema (1941) for the
migratory European shrimp, C rant/on cranyou. Survival of postlarvae within the
estuary may also be affected by decreases in temperature or salinity. In the
spring, postlarvae entering bays having relatively low temperatures and salinities
above ]'/,<> may be adversely affected by a sudden salinity drop, such as that caused by heavy spring rains. Conversely, if the temperatures are intermediate (18 C., for example) but salinities low (10'<'r or less), a drop in temperature may also decrease survival. Simultaneous decreases in both physical factors tem- perature and salinity would be most detrimental to the population in terms of both survival and growth. Williams (1 ( (>0) bad pre\ iously noted the effects of temperature and salinity on juveniles and subadults of I 1 . a:::lccns. Xot onlv did he find that the 96-hour survival of 42- to 100-mm. specimens declined with decreasing temperature over GROWTH AND SURVIVAL ()! I 1 . AZTElVS 215 the range 28.8 C. to 8.8 C., but he also determined that survival was most markedly reduced at 10/^r (the lowest salinity tested) regardless of the temperature. Animals exposed to 8.8 C. showed a greater tendency to lose the ability to regulate the osmotic concentration of the serum. It is of interest that juveniles were better able to regulate serum concentration than were adults (120 to 150 mm.) exposed to the same conditions. McFarland and Lee (1963) demonstrated that brown shrimp adults were better osmoregulators at higher salinity than at lower, with a greater tendency to isosmoticity when the external medium was below l8'/ ( (. The latter authors were unable to study animals in salinities below 5 f /tc to (>'/<( since only one of 12 adults survived 24-hour exposure to this range of salinity, despite an acclimation period of almost one week. The studies cited above suggest that salinity tolerance may vary not only with temperature, but also with size (age) of the shrimp. In demonstrating good survival of P. aztecus postlarvae over a broad range of salinity and temperature, the findings presented here suggest that postlarvae of this species are better os- moregulators than juveniles, which were tested by Williams (I960), or the adults tested by McFarland and Lee (1963). Further studies are planned to determine the effects of both temperature and salinity upon the osmotic behavior in various life-history stages of P. act ecus and I', setifcrus. SUMMARY 1. The combined effects of salinity and temperature upon growth and survival of postlarvae of the brown shrimp, Penaciis aztccns. were studied under controlled conditions. 2. Test salinity ranged from 2%o to 40/< c and temperature from 7 to 35 C. 3. With relatively short periods of acclimation, postlarval brown shrimp withstood wide fluctuations in both temperature and salinity for 24 hours. 4. The range of tolerance to these factors over periods of 28 days was only slightly less than that observed for 24 hours. 5. Postlarvae survived temperatures as low as 11 C. with almost no growth for one month in salinities of about lS%c or above. 6. Growth increased with temperature, with significant growth beginning al some temperature above 11 C. but below 18 C. The most marked increase- in growth rate occurred in the temperature region between 1 1 and 25 C. 7. At temperatures below 15 C., young (postlarval) shrimp demonstrated a decreased tolerance to low salinity. This reduced tolerance may influence the natural distribution and survival of postlarvae, which do not ordinarily enter the estuaries in abundance until spring when the temperature has increased to levels at which characteristically low estuarine salinities are no longer harmful. 8. Salinity per sc had little effect on either survival or growth, except at extreme temperatures. LITERATURE C IT I'D BEARDEN, C. M., 1961. Xoto mi pu>tlarvae ol" commercial shrimp ( I't'iuu -n\ ) in South Carolina. Cont. Bears Bluff Lab., No. 33, 1-8, Wadmalaw Island, S. C. Box, G. E. P., AND P. V. YOULK, 1955. The exploration and exploitation <>f response surfaces: An example of the link between the fitted surface and the basic mechanism of tin- system. Hitnnctrics, II: 287-323. 216 zori..\ p. /. MIX -ELD ix AXD DAVID v. AI.DRICH BROEKEMA, M. M. M., 1941. ScaMUial movements and the osmotic behaviour of the shrimp, Crangon crangon L. Arch. Xccrl. Zool., 6: 1-100. I'.i i'K! NROAII, M. D., 1934. The Penaeidea of Louisiana with a discussion of their world relationships. Hull. . liner. Mas. A'<;/. Hist.. 68: 61-143. COSTI.OW, J. D., JR., C. G. BOOKHOUT AXD R. MONROE, 1960. The effect of salinity and tem- perature on larval development of Scsanua cinercitui (Bosc) reared in the laboratorv. Biol. Bull., 118: 183-202. COSTLOW, J. D., JR., C. ( 1. BOOKHOUT AND R. MOXKOE, 1962. Salinity-temperature effects on the larval development of the crab, Panopcus herbstii Milne-Edwards, reared in the laboratory. Physiol. Zool., 35: 79-93. DAI. i., \Y., 1958. Observations of the biology of the greentail prawn, Metapenaeus inastcrsii i llaswell) (Crustacea Decapoda : Penaeidae). .lust. J. Mar. Fresh. Res.. 9: 111-134. GCXTER, <;., 145. Studies on marine fishes of Texas. Publ. Inst. Mar. Sci., 1: 1-190. GrxTER, ( i., 1950. Seasonal population changes and distributions as related to salinity of certain invertebrates of the Texas coast, including the commercial shrimp. Publ. lust. Mar. Sci.. 1(2) : 7-51. GTXTER, G.. AND G. E. HALL, 1963. Biological investigations of the St. Lucie estuary ( Florida > in connection with Lake Okcechobee discharges through the St. Lucic canal. Gulf Res. Rep., 1 : 189-307. GUXTEK, G., AND W. E. SHELL, JR., 1958. A study of an estuarine area with water-level control in the Louisiana marsh. Proc. La. Acad. Sci., 21: 5-34. < 1 1 XTER, G., J. Y. CHRISTMAS AXD R. KILLEBREW, 1964. Some relations of salinity to population distributions of motile estuarine organisms, with special reference to penaeid shrimp. Ecology, 45: 181-185. Jonxsox, M. C., AXD J. R. FIELDIXG, 1956. Propagation of the white shrimp, I'cnacus sctifcrus ( Linn.), in captivity. Tulanc Stud. Zool., 4: 175-190. KIXXK, O., 1960. Growth, food intake, and food conversion in a euryplastic fish exposed to different temperatures and salinities. Physiol. Zool., 33: 288-317. I.INDXKR, M. J., AXD W. W. AXDERSON, 1956. Growth, migrations, spawning and size distribu- tion of shrimp, Pcnacus sctifcrus. U. S. Fisli and U'ildl. Scn\, Fish. Bull. 106, 56: 555-645. .Mi FARLAXD, W. N., AXD B. D. LEE, 1963. Osmotic and ionic concentrations of penacidcan shrimps of the Texas coast. Bull. Mar. Sci. Gulf Caribb., 13: 391-417. PKARSE, A. S., AXD G. GUNTER, 1957. Salinity. /;;: Treatise on Marine Ecology and Paleon- tology. Vol. 1, J. W. Hedgpeth, ed. Geological Society of America, Memoir 67, 129-158, N. Y. Pi.Ak.sox, J. C., 1939. The early life histories of some American Penaeidae, chiefly the com- mercial shrimp Pcnacus sctifcrus (Linn.). Bull. U. S. Bur. Fisheries, 49(30) : 1-73. RKXFRO, \Y. C., 1964. Life history stages of Gulf of Mexico brown shrimp. U. S. Fish ami ll'ildl. Scr^.. Or. No. 183, 94-98. ST. AMAXT, L. S., K. C. CORKUM AXD J. G. BROOM, 1963. Studies on growth dynamics of the brown shrimp, Pcnacus aztccus, in Louisiana Waters. Proc. Gulf Caribb. Fish. Inst.. 15: 14-26. YIOSCA, P., JR., 1920. Report of the biologist. La. Dept. Coiiserv., 4th Bienn. Rep., 120-130. \VKYMOUTH, F. W., M. J. LIXDXKR AXD W. \Y. AXDKKSOX, 1933. Preliminary report on the life history of the common shrimp Pcuacus sctifcrus (Linn.). Bull. U. S. Bur. Fisheries, 48(14) : 1-26. \YM.I.IAMS, A. B., 1955. A contribution to the life histories of commercial shrimp {Penaeidae) in North Carolina. Bull. Mar. Sci. Gulf Caribb.. 5: 116-146. \Yn.i.iA.Ms, A. B., 1959. Spotted and brown shrimp postlarvae (Pcuacus) in North Carolina. Bull. Mar. Sci. Gulf Caribb., 9: 281-290. WILLIAMS, A. B., 1960. The influence of temperature on osmotic regulation in two species of i^tuarine shrimps (Pcnacus). Biol. Bui!., 119: 560-571. ZEIN Ki.mx, Z. P., 1963. Effect of salinity on growth of postlarval penaeid shrimp. Bi<>l. Bull., 125: 188-1%. Vol. 12Q, No. 2 October, 1065 THE BIOLOGICAL BULLETIN PUBLISHED BY THE MARINE BIOLOGICAL LABORATORY TUBE-BUILDING AXD FEEDING IX CHAETOPTERID POLYCHAETES ROBERT D. BARNES Department of Bioloi/y. Gettysburg Cullci/c, licttyslutr,/, The tube-building and feeding behavior of the large familiar Chactoptcnts vari- opedatus has been known since the studies of Enders (1908, 1909) and MacGinitie (1939). Much less was known about the other members of the family Chaetop- teridae until 1964. when the Atlantic chaetopterid, Spiochaetopterus ocitlatiis. was investigated by the author. This little species, having a pair of long palps and inhabiting a straight vertical tube, is a much more typical member of the family than is Chaetopterus. The purpose of this study therefore was to investi- gate the tube-building and feeding mechanisms of the remaining four chaetopterid genera; Tclepsavus, Phyllochactopterus, Ranzanidcs, and Mesochaetopterus. The greater part of this study was carried out in Naples, Italy, where repre- sentatives of every chaetopterid genus except Mesochaetopterus, occur in the Bay of Naples. The author wishes to express his appreciation to the Stazione Zoologica at Napoli for the facilities and courtesies extended to him during the three months of residence at the laboratory, and also to the National Science Foundation for their support of space utilized at the laboratory. The author is indebted to Dr. R. Phil- lips Dales of Bedford College, University of London, who provided unpublished data from his observations of Mesochaetopterus, and also to Dr. Marion Pettibone of the U. S. National Museum for the loan of specimens of Mesochaetopterus. MATF.KIALS AND METHODS All of the living specimens utilized in this study were collected by dredging in water ranging in depth from two to 50 meters. The small size and relatively shallow depth of the tubes of these chaetopterids piv\cnU-d any excessive damage by the dredge. To study feeding and other behavior the worms were transferred from their natural tubes into glass capillary tubes. The diameter of the capillary tube was critical for the adaptation of the worms to this artificial environment ; but if the fit was a good one, the worms lived for as long as two months. The process of trans- fer from the natural tube to a glass capillary tube was most easily accomplished 217 Copyright 1965, by the Marine Biological Laboratory 2 IS ROMKK'T I) I'.ARNKS by means of a hypodermic syringe \\ith a small needle. The needle was inserted into one end of the natural tube and a strong stream of sea water was then in- jected. This rapidly forced the worm in an undamaged condition out of the oppo- site end of the tube. The needle of the syringe was then inserted into one end of the glass capillary tube and the syringe slowly filled. The filling syringe created a current of sea water through the tube sufficient to suck the worm into the capil- lary tube. The capillary tubes were placed within a glass cylinder. A plug of glass wool held the tubes in a vertical position against the inner wall of the cylinder, and a short piece of large glass tubing penetrated the center of the plug to permit ade- quate water circulation. When the worms were not being studied, the entire glass cylinder was submerged within a tank of circulating sea water. The worms were observed through the cylinder wall by means of a horizontally oriented dissecting microscope. The base of the microscope had been removed and the upper optical portion was attached in a horizontal position to a ring stand. Observations of tube-building were facilitated by confining the worms to very short sections of natural tube. The worms would then frequently construct addi- tions to the tube. Determination of water current and degree of tube obstruction was aided by the use of carmine-stained sea water injected into the tube. A sus- pension of carmine particles in sea water was used to study ciliary tracts and feeding. Observations of feeding were also aided by using an artificially stained detritus. The detritus was prepared by boiling a small amount of cooked pasta in carmine and then grinding and suspending it in sea water. RESULTS Telepsaz'its costantin Claparede Tclcpsui'iis costanun Claparede is one of two species known for the genus. It is cosmopolitan and in the Western Hemisphere occurs along the Pacific coast of North America. This species was collected from the Bay of Naples at depths of four to fi\e meters from a bottom of fine sand and silt. The tube of Tclcpsavus and the structure of the worm itself are almost identical to that of Spiochaetopterus (Fig. 1, P>). Telepsanis secretes an opaque cornified annulated tube (Figs. 2 and 3, A ) which is buried vertically in the substratum. Only a small part of one end of the tube projects above the surface of the sand. In the Bay of Naples the longest dredged tube was 25 cm. but longer tubes are prob- ably common. The internal diameter ranged from 1.2 to 1.4 mm. The lower re gion of the tube commonly contains a secreted button-like transverse partition (Fig. 3, E) which is perforated by several openings to allow a water current to pass through the tube. The total length of TclcpsaTiis costantni averages about S cm. and, as in all chaetopterids, the body is divided into three regions. The anterior region ( Fig. 1, A i contains nine segments, indicated externally only by the presence of the nine short lobe-like notopodia ; the anterior nenropodia are lost in rdl chaetopterids. Kach notopodium is supplied by a bundle of capillary .setae. The fourth noto- podium, in addition, carries a large, heavy, blade-like seta. The anterior end of the body (Fig. 3, C) is truncate, the ventral margin projecting beyond the mouth. CHAETOPTERIDAE: TUI'.E AND FEEDING 210 A small lip flanks the mouth dorsally and lies between the bases of two long heavy palps, which may equal or exceed half the body length. The entire convex ventral surface of the anterior body region is covered by a thick glandular epidermis which secretes the tube. The tube is secreted in half- cylinder sections. When an addition to the tube is to be secreted, the worm slowly r i , - CUTTING .-SETA PALPS ANTENNA'-- ~ TELEPSAVUS SPIOCHAETOPTERUS PHYLLOCHAETOPTERUS TEARING .- SETA PUMPING SEGMENTS .. ^ SEGMENTS. MESOCHAETOPTERUS RANZANIDES FIGURE 1. Lateral view of anterior and middle body regions of representatives of each of the six chaetopterid genera. Mucous bags are indicated by shaded areas enclosed by dashed lines. extends almost the entire anterior region of the body out of the tube. Simultane- ously, the body is flexed dorsally at the level of the 4th or 5th segment and ap- pears very flared and turgid. At the end of the extension movement, the body is quickly withdrawn into the tube, leaving behind a delicate half-cylinder of new tube. The worm then rotates 180 within the tube and secretes the opposite half- cylinder. The length of the addition corresponds to the distance between two annulations. 220 KOMKKT 1). I5ARNES The laying down of a transverse i.artition was never observed in Telepsavus. However, since the partitions are identical to those of Spiochaetopterus, they are probably constructed in the same manner (Barnes, 1964). In Spiochaetopterus the worm assumes a head-downward position in the tube and at the level at which a partition is to be placed, the Ik-ad of the worm is slightly flexed dorsally. The partition is then laid dmvn during a rapid rotating movement of the anterior end. IMC.CKK 2. I'art \ tin- tnl>r of Telepsavus c The anterior \entral margin of the head projects through a central opening in the partition at the end of the rotation. This single opening is later reduced to two to four smaller openings as the secretory .surface of the worm is moved back and forth across the partition. "\Yliv the opening is not completely obliterated is not understood. Partitions are removed exactly as in Spiochaetopterus. The worm assumes a head-downward position in the tube. At the level of the jiartition the body is flexed dorsally 1S()' J so that the angle of flexure is located at the 4th parapodia. The flexed region of the body is now rotated a little to one side, Usually toward the left CHAETOPTERIDAE: TUBE AND FEEDING 221 side, so that the enlarged blade-like 4th seta is directed downward against the periphery of the partition. The seta is now extended, cutting through at the junc- tion of the partition and the wall. Then the seta is retracted. Following each stroke, the worm rotates slightly in the tube. In less than two minutes the worm neatly cuts the partition completely free. The old partition is pushed downward and against the tube wall and is gradually incorporated into the wall itself as addi- tional reinforcing secretions are laid clown by the worm against the inner surface of the tube. DORSAL CILIATED GROOVE CILIATED NOTOPODIAL RINGS MUCOUS BAG *'- CUPULE BLOOD VESSEL EJECTION GROOVE - _JL -CILIATED GUTTER COELOM FIGURE 3. Telepsarns custaniui. A. Upper end of tube. B. Dorsal view of three seg- ments of posterior body region. C. Dorsal view of anterior end of body showing grooves on palps. D. Cross-section of palp. E. Surface view of a tube partition. The modified 4th setae are also used to cut open or rupture the tube wall, per- mitting the formation of a new extent of tube at this point. Such a new addition was always observed at the lower end of the tube and the entrance to the old lower section of the tube was sealed over. The middle body region commonly contains 31 segments although the number is not constant. The parapodia are biramous. The neuropodia (Fig. 1, A) are broad, rounded lobes provided with uncinate setae and are used for anchoring the body to the tube wall. The notopodia have a foliaceous structure (Fig. 3, F). Each notopodium consists of two main divisions, one dorso-medial and one dorso- lateral. The dorso-medial division is again divided into two rami. One ramus is directed dorso-medially and contacts the corresponding ramus of the opposite noto- podium. Together the two opposing rami enclose a large ring-like mid-dorsal KOUKKT D. BARNES opening. The other ramu> of the dor-M>- medial division is directed ventrally and contacts the dorso-lateral division of the- notopodium. This contact likewise en- closes a lateral ring-like opening, one on each side. Thus there are three noto- podial rings, one dorsal and two lateral, at the level of each segment in the middle body region. The posterior body region t Fig. -\ B ) varies from a few to many segments. The nenropodia of this region are similar to those of the middle body region; the notopodia are simple antenna-like projections bearing a seta at the tip. The notopodial rings of the middle body region are lined by large membranelles. The membranelles beat continually and the beating occurs as several counter- clockwise waves mm ing around the ring margin. The beating of the membranelles in the notopodial rings of the middle body region drives water through the tube, creating the water current upon which the worm depends for respiration, for food, and for the elimination of waste. Like other chaetopterids, Teli'f>s<.ri us obtains food bv straining the tubal water current through a mucous bag. A single mucous bag is employed by Tdcpsai'it* costanini. The bag is secreted by the second mid-dorsal notopodial ring (Figs. 1, A and 3, F) which is slightly heavier than the other mid-dorsal rings of the middle body region. The end of the mucous bag is caught by a large ciliated cupule located medially just in front of the third dorsal notopodial ring. The cilia in the cupule beat backward, and roll the gathered end of the mucous bag into a ball. As one end of the bag is rolled up in the cupule. additional mucous film is secreted at the opposite end. The notopodial ring which secretes the mucous bag is also lined by membranelles and all of the water driven through this ring must pass into and through the mucous bag. Plankton and tine detritus are strained out and incorporated into the slowly enlarging mucous food ball being formed in the cupule. When the food ball has reached a certain size, secretion of mucus is halted, and the bag is detached from the notopodial ring. Xow the food ball moves out of the cupule and is carried for- ward along a mid-dorsal ciliated groove (Fig. 3, F). The flanking ridges of the groove bifurcate just in front of the small dorsal lip of the mouth. One ridge of the groove passes toward the side of the lip, and the other ridge passes to the oppo- site side. Each ridge gradually diminishes. The food ball, on reaching the bifur- cation of the ciliated groove, passes over the dorsal lip and into the mouth. A small amount of mucus is secreted by the first notopodial ring and is collected by a rudimentary cupule located immediately behind the ring. The mucus is never elaborated as a distinct bag and appears to be of little importance in feeding. As in Spiochaetopterus, the tuo long anterior palps play a minor role in feeding. Fach pal]) is provided with a deep ciliated gutter located on the dorsal side (Fig. 3. C and D). Small particles which hi come lodged in the gutter are carried down the length of the palp by the beating cilia. At the base of the palp the gutter passes onto the lateral margins of the mouth. But only rarely in Tclcpsa^'us were parti- cles ever observed being carried within the palpal gutter. This was true not only for introduced suspensions of carmine particle- and stained detritus but also for natural particles. The principal function of the palps is the removal of feces and the maintenance of an unobstructed tube. Just medial to the ciliated gutter is a small ciliated groove CHAETOPTERIDAE : TUBE AND FEEDING (Figs. 3, C and D). In contrast to the downward beating cilia of the larger palpal gutter, the cilia of the smaller groove beat distally. Any undesirable particles which are brought into the tube by the water current must pass over the palps before reaching the body proper and the notopodial rings. When such particles contact the palps they are quickly swept onto the ejection groove and then transported along the groove to the tip of the palp. At the same time the worm moves upward in the tube until the palps project out of the tube opening. Material being carried along the ejection groove drops from the tip of the palps and falls outside of the tube. The palps are highly effective in clearing the tube of undesirable material. When stained detritus or a suspension of carmine particles was introduced into the upper end of the tube, over 90% was quickly ejected by the palps. Feces are egested from the posterior anal opening in the form of small pellets. The pellets are immediately picked up by the mid-dorsal ciliated groove, which runs the entire length of the body and in the middle and anterior body regions also functions as the food groove already described. The fecal pellet is carried ante- riorly along the groove. In the middle body region the apposing notopodia form- ing the mid-dorsal ring separate when the pellet moves through the ring. Their separation thus reduces the chance of the pellet being swept out of the groove by the opposing beat of the membranelles lining the ring. When the fecal pellet reaches the anterior end of the mid-dorsal groove, it does not pass over the dorsal lip as does the food ball. Rather, the fecal pellet follows either one of the two ridges which separate and swing to either side of the dorsal lip. The ridge carries the pellet toward the ejection groove at the base of the palp. The fecal pellet is then carried the length of the palp to the tip. Simultaneously, the worm moves upward in the tube and projects the palps to the outside so that the fecal pellet falls away from the opening of the tube. Phyllochaetopterus socialis Claparede Phyllochaetopterus socialis Claparede was dredged from a bottom of fine sand mixed with silt in about two meters of water. Only small numbers of specimens \vere collected. This species is a very small chaetopterid, measuring only 15-25 mm. in length not including the palps. The structure of Phyllochaetopterus socialis (Fig. 1, C) is essentially like that of species of Telepsafus and Spiochaetopterus. It differs from the members of the other two genera in only minor respects. In PJi \llo- chaetopterus the dorsal lip is very large and the ventral lip is cleft (Fig. 4, D and E). There is a pair of small antennae-like structures located directly behind the palps. They extend anteriorly only slightly beyond the margin of the head. These antennae-like processes occur only in this genus and represent modified parapodia, for each contains a single seta. The true palps of Phyllochaetopterus are somewhat shorter than those of Spiochaetopterus and Tclcpsai'its, approxi- mately equaling the anterior body region in length. The anterior body region contains 13 setigerous segments, and the middle body region contains from four to ten segments. The tube of Phyllochaetopterus socialis tends to be branched and crooked (Fig. 4, A and C ) . Although part of the tube is always buried, a considerable extent 224 R( IBERT D BARNES may lie liori/ontally above the surface of tin- Mikstratum. The length of the tube ranges from 3.0 to 6.0 cm. and the internal diameter from 0.45 to 0.80 mm. The luhe is brown in color and has a tough leathery texture and appearance without any external annulations. In Phyllochaetopterus socialis one to four worms may inhabit a single tube. The individuals may occupy separate branches or the same section of the tube, but there is no definite correlation between the number of tube branches and the number of occupants. In general there is usually one main extent of tube with two openings and any side branches tend to be sealed off from the main sec- tion. ^Multiple occupancy of a single tube i> not limited to Phyllochaetopterus so- -- DORSAL LIP-. -ANTENNA - DORSAL CILIATED GROOVE D FIGURE 4. Phyllochaetopterus socialis. A. Three worms within a common tube. B. Sur- face view of a partition. C. Part of tube. D. Dorsal view of anterior end of body. E. Ven- tral view of anterior end of body. F. A recently constructed section of tube adjoining an older section. cialis but occurs in some other members of the genus, such as Phyllochaetopterus prolifica from the Pacific coast of North America. The condition is believed to result from fission of the original builder of the tube. Partition:-, are located within the interior of the tube and occur anywhere along the tube length. The structure of the partition (Fig. 4, B) is similar to those of YV/c/\v</7'//.s- and Spiochaetopterus. A number of times two worms were placed in one tube. In one instance one of the worms placed a partition between the two occupants. In other cases no partition was constructed and the two worms fre- quently passed each other in the tube. Phyllochaetopterus secretes its tube in a much less regular fashion than does '/\'Icf>str;'its or Spiochaetopterus. The worm lays down small crescent-shaped over- lapping -ections of varying size (Fig. 4, F). During the process of secretion, the body of the worm is not markedly arched nor projected very far out of the tube. Partitions are cut out from the tube in the same manner as in Ti'lcsaTHs and CHAETOPTERIDAE: TUBE AND FEEDING 225 Spiochaetopterus and are probably laid clown in the same way also, but they were never observed being secreted. As in Tclcf>sonts and Spiochaetopterus, water is driven through the tube of Phyllochaetopterus by the beating of the membranelles bordering the rings formed by the foliaceous notopodia of the middle body region. Phyllochaetopterus utilizes three methods to obtain food. Feeding may involve mucous bags as in Spiochaetopterus. A mucous bag is secreted by the middle ciliary ring of the more anterior foliaceous parapodia, except for the first (Fig. 1, C). Each bag is caught by a cupule located behind the ciliary ring. As many as eight mucous bags and rotating food balls were observed being formed at one time. An alternate method to the use of mucous bags appears to be stimulated by the presence of a heavy concentration of food particles in the water passing through the tube. Under these conditions the notopodial rings spin out a mucous rope instead of bags. The rope picks up and traps particles in the swirling water current streaming through the notopodial rings. The rope joins with that of other seg- ments to form a continuous twisting strand. Mucus for the rope appears to In- supplied not only by the notopodial rings which secrete the mucous bags but also by the lateral margins of the mid-dorsal longitudinal ciliated groove. A conspicu- ous whitish glandular strip flanks the groove in both the middle and posterior body region. The mucous rope extends well into the posterior body region and it may well be partly secreted in this region. Great quantities of mucus are evident when Phyllochaetopterus is removed from its tube. The worm becomes so wrapped up in mucus that it is difficult to handle. The source of the mucus may be the glandular strips bordering the dorsal ciliated groove. Such large amounts of mucus were not found in any other of the chae- topterids studied and none possess the glandular strips. The palps also seem to be of some importance in feeding. When large amounts of artificial detritus or suspended carmine particles were introduced into the gla^s tube, the greater part of this material would be collected by the major groove, or ciliated gutter, of the palps and conducted downward to the mouth. Material ap- peared to be conveyed as easily when the contact was superficial as when material was lodged deeply in the groove. Feces are removed by way of the dorsal ciliated groove and the ejection groove of the palps. Fecal pellets of specimens in capillary tubes were commonly stuck to the rim of the tube opening or even to the underside of a tube partition, where a partition had been placed above the worm. The palps of Phyllochaetopterus are also used to remove undesirable objects from the tube brought in by the water current. But this species is less active than other chaetopterids studied and moves rather slowly up and down the tube. Ransanides sagittaria ( Claparede i Ranzu niilcs sac/ittaria (Claparede), which is known only from the Mediter- ranean, is the most abundant chaetopterid in the Bay of Naples. Individuals tend to occur together in close associations, and large masses of hundreds of adjacent tubes were dredged from fine silt and sand in 10-12 meters of water. The tubes are composed of an outer layer of sand grains (Fig. 5, A) separated by an inner 226 KOBKRT IX RARNES secreted cornified organic lining, probably of similar composition to that of other chaetopterid tubes. The length of the tubes ranges from 4.5 to 8.5 cm., with a bore of 07-1.0 mm. Although these worms occur in compact masses, there is little fusion of adjacent tubes. The tubes are more or less straight, oriented paral- PALP DORSAL CILIATED GROOVE DORSAL CILIATED GROOVE RIDGED SURFACE - MUCOUS BAG CUPULE FIRST PUMPING SEGMENT D FIGURE 5. Ransanides sn/iitt<n-i<i. A-D. Tube construction. A. Sand grains being brought to ventral lip by palps. B. Sand grains lining moved to under (outer) surface of lip. C. Ven- tral lip pressing sand grains to rim of tube. D. Worm laying down secreted lining of tube. E. Bundle of enlarged 4th notnpodial setae puncturing a tub- partition. F. TuV partition in place with five perforations. G. Ventral view of anterior end of body. H. Dorsal view of anterior end of body. I. Lateral view of four mMd'e body segments in pumping position. J. Dorsal view of section of middle body rcL-ion involved in secreting mucous bag. Mesochae- toptcnis tttylori. K. Dorsal view of one .segment of middle body region involved in M-creting mucous bag. ( IIAKTOI'TKKIDAK: TLT.K \XD FEEDING lei to each other, and rest vertically in the substratum with one opening of the tube at the surface. Ranzdiiides is only a little larger than Phyllochaetopterus socialis. The length exclusive of the palps, is approximately 2.0 cm. to 2.5 cm. The structure of this species (Fig. 1, F) departs considerably from that found in Spiochaetopterus, Telepsavus, and Phyllochaetopterus. The palps are long and are similar to those of other chaetopterids. The ventral lip (Fig. 5, G and H) is very large and flaring. Eye spots are present. The anterior body region consists of 12 setigerous segments. The usual single lobate notopodium composes the parapodia. The fourth parapodium carries five very heavy setae in addition to a bundle of ordi- nary setae. The middle and posterior body regions (Figs. 1, F and 5, I and J) are not sharply demarcated. All of the parapodia are biramous with the neuropodium unci- nate. The first parapodia of the middle body region lie immediately behind the 12th and last parapodia of the anterior body region and possess a short antenna-like notopodium. The second parapodia of this region lie considerably behind the first and their notopodia are large and wing-like. The third and remaining para- podia are placed at regular intervals and the notopodia have the form of short stubby fingers. The length of the notopodia gradually increases posteriorly and the notopodia of the posterior body region eventually assume an antenna-like form similar to that of other chaetopterids. The secreted part of the tube is laid down by the ventral surface of the anterior body region as in other chaetopterids. The large flaring ventral lip is responsible for molding the outer sand grain layer. In the construction of an addition to the tube, the outer sand grain layer is added to the old tube before the inner secreted lining. This process begins with the collection of sand grains. The anterior end of the worm is projected from the aperture of the tube and may be arched ven- trally so that the upper (inner) surface of the ventral lip contacts the substratum. Particles of sand adhere to the mucus on the lip surface. Sand particles may also be collected by the palps (Fig. 5, A) in the same manner. Adhering particles are then conveyed downward to the ventral lip in the major groove of the palp. Not infrequently a palp is wiped against the lip. The lip surface is strongly ciliated and the sand particles are driven over the edge onto the under (outer) surface (Fig. 5, B). Periodically the worm retracts into the tube until the lip fits around the rim of the aperture like a collar (Fig. 5, C). In this position the lip acts as a mold and the sand grains which have accumulated onto the ventral lip surface are added to the end of the tube. At frequent intervals the ventral secretory surface of the worm is applied against the inner surface of the sand grains, laying down the inner secreted part of the tube and also securing the sand grain layer (Fig. 5, D). Worms living in glass tubes commonly constructed partitions at various points within the tube. The partitions of Ranzanidcs do not have the distinct form and organization of those of other chaetopterids. The partition is merely a simple sheet of secreted material, often oriented obliquely across the tube (Fig. 5, F). Several perforations are present to permit the flow of water through the tube. In laving down a partition the worm merely bends the anterior end ventrally across the tube and secretes a film of material in this position. There is no rota- 22S K ( (BERT D B \KXES lion of the anterior end to form a distinct disc as in otluT chaetopterids. The per- forations are ])ro(luce(l by the -4th setae. Following secretion of the ])artition, the worm flexes within the tube so that the 1th parapodia are at the level of the flexure. The body is twisted slightly i om side and the bundle of 5 heavy setae of the right fourth parapodium arc- thrust through the partition and then spread like a fan to widen the opening (Fig. 5, E). The worm removes the partition by ripping it out. The fourth setae are used to tear away the partition at its junction with the tube wall. The body of the worm is then pushed through the opening. As in other chaetopterids, the 4th setae are also used to rip open the side of the tube wall in order to construct a new extent of tube. The old branch of the tube is then sealed off from the addition, thus always preserving what is essentially a non-branched straight tube. Water is pumped through the tube of Ranzanides by the peristaltic action of the segments of the middle body region. Following the longitudinal contraction the diameter of a segment at the level of the parapodia is increased until the segment fills the tube (Fig. 5, I). Dorsally the two short finger-like notopodia fold over the mid-dorsal groove, protecting the groove and forming a dorsal margin of con- tact with the tube wall. The segment is then moved posteriorly like a piston driv- ing water downward through the tube. The effective stroke occurs in an ante- riorly directed wave with one segment moving downward after another. In the recovery stroke the diameter of the segment is greatly decreased with a resulting greatly lowered water resistance. Pumping is more or less continual except when the worm is rapidly moving up or down the tube. But the strength and rate of pumping vary greatly and are dependent upon the rapidity of the peristaltic waves and the anterior-posterior length of the stroke. Although water is commonly driven through the tube to the posterior of the worm, reverse pumping was observed on a number of occa- -ions, particularly when undesirable material had entered the tube. Raii.::ani(lcs is a very active worm. It can move rapidly up the tube, employing the anterior notopodia in a somewhat leg-like manner as is true of other chae- topterids. Also like other chaetopterids it frequently reverses position within the tube. Ranrjanuh's employs a mucous bag for feeding. A single bag is utilized and is -ecreted by the large wing-like second notopodia of the middle body region (Fig. 5, J). The bag is caught by the large cupule located halfway between the second and third parapodia. The palps function as accessory feeding organs, conducting detritus particles along the major palpal groove to the mouth. But only small amounts of material were observed being obtained in this way. When a suspension of carmine particles was injected into a capillary tube containing a worm, the greater part of the sus- -ion was ejected back out of the tube. A small amount was collected by the major groove of the palps and conducted downward to the mouth, and most of that which got past the palps was collected by the mucous bag. Rev rse peristalsis, or pumping, of the middle body region is apparently of primary importance in ridding the tube of any sudden invasion of undesirable mate- rial. In this way the greater part of an introduced carmine suspension was ex- pelled. The ejection groove of the palps, however, still functions in removing CHAETOPTERIDAE : TUBE AND FEEDING 229 large undesirable particles which enter the tube. The palps are also important in removing fecal waste. Fecal pellets released from the anus travel the dorsal ciliated groove along the entire' length of the worm and then are expelled from the tube by the palps. Mesochaetopterus taylori Potts The author did not observe tube-building and feeding behavior in living speci- mens of Mesochaetopterus, which can be most easily collected along the west coast of North America, but preserved specimens of Mesochaetopterus taylori Potts from the coast of Washington were examined. When the structure of this species is compared to that of the other chaetopterids studied, a number of deductions regard- ing its tube-building and feeding behavior can be made. Mesochaetopterus taylori inhabits a very long tube which is oriented vertically in the substratum. Although only fragments of tubes were examined by the author, the total length of the tube may exceed a meter and numerous collectors have at- tested to the difficulty of digging up intact specimens. The tube is composed of an outer layer of sand grains adhered to an inner secreted organic lining, but in large tubes the sand grain layer is often inconspicuous and the secreted layer has a parchment-like texture similar to the tube of Chactoptcrns. Nothing can be stated regarding the presence or absence of partitions. Species of Mesochaetopterus tend to be somewhat intermediate in size be- tween Cliactoptents and the other chaetopterids. The single intact specimen of M. tavlori examined by the author had a total length of 25 cm. The anterior body region (Fig. 1. E) is essentially like that of other chaetopterids. There are nine setigerous segments, with especially well-developed notopodia. The 4th notopodia carry a bundle of heavy setae like those of Ranzanides. The palps slightly exceed the anterior body region in length and bear both a ciliated gutter and an ejection groove. The middle body region (Figs. 1, E and 5, K) displays marked resemblances to that of Ranzanides. The first pair of parapodia follow immediately behind the ninth and last notopodia of the anterior body region. It consists of a finger-like notopodium and an uncinate neuropodium. The second and third notopodia are aliform and each is followed by a large bivalved cupule. The dorsal surface of the body following the first three parapodia of the middle body region is strongly concave and transversely ridged. The remaining parapodia of the middle body region consist of short finger-like notopodia and uncinate neuropodia. Posteriorly the notopodia tend to become antenna-like and these segments may constitute a posterior body region as in h'anrjanidcs. A dorsal groove runs the length of the body. It is possible that Mesochaetopterus taylori constructs its sand grain-secreted tube in a similar way to that of K'aiizaiiidcs, although the sand grain layer appears to be less important in Mesochaetopterus. The bundle of heavy 4th setae is at least employed to open the side of the tube wall. If partitions do exist, then these setae may be used to perforate them or remove them. The water current passing through the tube is undoubtedly generated by peri- staltic contractions of the 4th and remaining segments of the middle body region. These segments are virtually identical to the pumping segments of Ranzanides. 2M) KOMKk r I) BARNES The presence of tin- two pair> of aliform notopodia, each followed by a large cupule, clearly indicates a feeding mechanism employing two mucous bags (Fig. 1, E). This conjecture has been con !i lined by the observations of Dales at Friday Harbor. Potts ( W14) claimed that when the animal is within its tube, the lateral margins of these three segments of the body are arched over toward each other. partially enclosing the dorsal surface. \Yithin this enclosed space would lie the cupules (the over-arching lateral margins are not included in Figure 1, E in order that the mucous bags and cupules can be seen). The transversely ridged dorsal surface characteristic of these segments would line the enclosed tubular area, but the significance of the ridged surface is difficult to understand. The secretion of two mucous bags is not characteristic of all species of Meso- chaetopterus. M. viinntns possesses but a single pair of aliform notopodia and one cupule. which indicates the formation of only one mucous bag. DISCUSSION The members of the Chaetopteridae display a relatively uniform structure and belmior pattern with regard to tube-building and feeding mechanisms. The only atypical member is Chaetopterus variopedatus, which, being the most familiar spe- cies, has unfortunately tended to color the conception of the family for many zoologists. The typical chaetopterid is a small worm inhabiting a more or less straight tube oriented \ertically in the substratum. One opening of the tube projects above the surface of the sand or mud. A branching tube occurs in species of Phyllochaetop- terus and in Mesochaetopterus iitiinttiis, but at least in Phyllochaetopterus socialis the branches, even when inhabited by another worm, tend to be sealed off from a main section. The tube is always composed of an organic secreted material. The secreted material is cornified in Telepsafus and Spiochaetopterus. In Phyllo- chaetopterus, Mesochaetopterus, and Chaetopterus it may be leathery or parchment- like. In species of two genera, Ranzanidcs and Mesochaetopterus, there is an outer layer of sand grains cemented to the secreted part of the tube. In all chaetopterids the tube is secreted by the convex ventral surface of the anterior body region. A striking feature of the tubes of Spiochaetopterus, Telcpsaviis, Phyllochaetop- terus, and Raii:::aiiides is the presence of perforated transverse partitions. In Spio- chaetopterns and Tclcpscnus, the partitions are always located near the bottom of the tube, and in an earlier paper (1 ( >(4| the author suggested that the partition functions to prevent the collapse of the thinner-walled tube in this region. This may well be one function ot the partition in these two genera; but it can not be the only function, for in Phyllochaetopterus and Ranzanidcs the lower part of the tube is not particularly delicate nor are the partitions always limited to this level. I'ossibly the chief function of the tube partition is to modify the water pres- sure in some way within the tube. The rondition of the tube in Chaelopterus would seem to support this conjecture. The tube of Chaetopterus lacks partitions, but the two openings of the tube have a much smaller diameter than does the greater part of tube lying beneath the surface of the substratum. These differences in the tube diameter would reduce the speed ot the water current and perhaps account for the absence of partitions in Chaetopterus. If partitions do function in modifving the CHAETOPTERIDAE: TUBE AND FEEDING 231 pressure of the water current, then it is very likely that such partitions will be found to occur in the tubes of Mesochaetopterus. The fourth notopodia of all chaetopterids carry heavy modified setae. These setae are used for cutting open the tube wall to permit the construction of a new branch or extent of tube, and they are also used for removing partitions and some- times for perforating partitions. In Spiochaetopterus, Tclepsarus and Phyllo- chaetopterus, the 4th notopodium carries a single heavy truncate blade-like seta, which is adapted for neatly cutting out the more button-like partitions constructed bv species of these genera. In other chaetopterids, the 4th notopodium carries a bundle of heavy spear-like setae which pierce and tear rather than cut. As in most sedentary tubicolous polychaetes, chaetopterids are totally dependent upon a current of water passing through the tube. The water current brings in oxygen and food and also removes excreted and gaseous waste. The current is generated in two ways. In Spiochaetopterus, Tclcpsai'us, and Phyllochaetopterus, the current is produced by the beating of cilia (probably membranelles) lining the ring-like openings created by the foliaceous notopodia of the middle body region. In Chaetopterus, Ranzanides, and Mesochaetopterus, the water current is produced by peristaltic contractions of the piston-like segments of the middle body region. There are three such segments in Chaetopterus (Fig. 1, D) and they are modified somewhat differently from the many pumping segments of Ranzanidcs and Mesochaetopterus. The primary method of feeding in all chaetopterids is the straining of water through a mucous bag, a unique mechanism found in few other animals. The secretion of the bag is the function of certain notopodia of the middle body region. The number of bags secreted simultaneously varies. A single bag is employed by Telepsa-rus, Ranzanidcs, Chaetopterus (Fig. 1, D), and Mesochaetopterus ininutus. Two bags are spun by Mesochaetopterus taylori and eight or more by Spiochae- topterus and Phyllochactopterus. A characteristic feature of the family is a pair of palps that arise from the ante- rior dorsal surface just behind the mouth. With the exception of Chaetopterus, the palps are heavy and long. In Chactoptcrus the palps are very short and small (Fig. 1, D). Each palp is provided with a deep longitudinal groove or gutter, lined with downward beating cilia. It is possible that the palp and its ciliated gutter represent the ancestral means of obtaining food in the Chaetopteridae. This is the method of obtaining food in the Spionidae, a tubicolous family closely related to the Chaetopteridae. The evolution of the mucous bag for feeding in the chae- topterids permitted the utilization of finer food particles than could be obtained by the palps. The palps will play a minor accessory role in feeding in most chae- topterids, and in Phyllochactopterus are perhaps as important as the mucous bag. The principal function of the chaetopterid palps is that of ejection of fecal pellets and unwanted debris which enters the tube with the incoming water current. Fecal pellets are carried anteriorly from the anus along a mid-dorsal ciliated groove lo- cated to the medial side of the ciliated gutter of the palp. The cilia of the ejection groove carry the pellet to the distal end of the palp, which at the time of ejection projects from the tube opening at the surface. Similarly, large undesirable parti- cles or objects which enter the tube are caught on the palp surface, transferred to the election groove, and conveyed back to the exterior. ROl'.KKT D. I'.ARNES The ejecting function of the chaetopierid palps is correlated with the straight vertical tube which these worms inhabit. Although such a tube is open at both ends, the lower end is buried in >and and mud. The downward-moving water current can leave the tube by passing into the interstitial spaces of the surrounding substratum, but large masses of debris or foreign objects, even if they passed the worm without interfering with its feeding and pumping behavior, would even- tually clog up the lower end of the tube. Feces would also contribute to the clogging of the tube and must therefore be removed from the opposite end of the tube. The primary function of the palps is therefore to maintain an unobstructed tube. The situation in Clhtctoplcyus is quite different. The tube is U-shaped and provided with both an inhalant and exhalant surface aperture. There is no need to move undesired objects back out of the inhalant opening. Unwanted material which enters the inhalant opening of the tube is pumped through the tube and out the exhalant opening. Significantly, the palps of Clntcloptcrus are greatly reduced in size. The major groove is still present but the ejection groove is absent. Fecal pellets are also flushed out by the exhalant water current, and the mid-dorsal cili- ated groove, which in other chaetopterids extends the length of the body as a means of transporting fecal pellets, functions only to carry food balls and extends from the cupule to the mouth. The peculiarities of Chactoptcnis are clearly corre- lated with the U-shaped structure of its tube. The chaetopterids and the spionids probably evolved from some common, an- cestral tubicolous polvchaete. having palps as organs for obtaining detritus as food. The spionids retained this function of the palps. The chaetopterids, however, shifted to a feeding mechanism in which the water current passing through the tube was strained through a mucous bag; the palps were employed for maintaining an un- obstructed tube. The chaetopterids appear to have evolved along three main lines, each of which should probably constitute a single genus. One line embraces SpiochaZtopterus, Telcrsurus, and riiyllocliuctof'tcnis. in which the water current of the tube is gen- erated by the ciliary rings of the foliaceous notopodia. The second line includes /\'<ni;::ani(lcs and Mcs<iflniclof>tcni.\\ which have the tubes covered by an outer layer of sand grains and pump water through the tube by means of the peristaltic con- tractions of a large number of segments of the middle body region. The third line is represented by Cliactoptcrus. Mere the tube is U-shaped with two openings to the surface, the palps are greatly reduced, and a water current is produced by the peristaltic contractions of three speciali/ed segments. Chaetopterus is probably more closely allied to the Ranzanides-Mesochaetopterus line than to the Spioclmc- topterus-Phyllochaetopterus-Telepsavus group. ME MARY 1. Tube-building and feeding were investigated in members of the chaetopterid genera. 'fclcpsin-Hs. Phyllochaetopterus, kauzanidcs and Mesochaetopterus. 2. With the exception of Chaetopterus, all members of the family construct a more or less straight tube oriented vertically in the substratum. The tube con- tains one or several transverse perforated partitions. CHAETOPTERIDAE: TUHK AXD FEEDING 3. The tube is secreted by the ventral surface of the anterior body region. The enlarged fourth notopoclial setae are used to remove partitions or to tear open tin- side of the tube wall in order to construct a new section of tube. 4. In Tclef>sa"c"its and PhyUocliacioptcnts water is driven through the tube by the beating of ciliary membranelles. The membranelles line the ring-like opening- formed by the foliaceous notopodia of the middle body region. In Raiizanidcs. Mesochaetopterus, and Chaetopterus water is pumped through the tube by the piston-like action of segments of the middle body region. 5. A mucous bag is utilized for feeding in all chaetopterids. The number of bags varies from one to many and they are always produced by the middle body region. 6. Except in Chaetopterus, a pair of long palps arise from the dorsal side of the head. Each palp carries a large and a small ciliated groove. The large groove, in which cilia beat proximally, functions as an accessory feeding device. The more important smaller groove, in which cilia beat distally. provides for the ejec- tion of fecal pellets and any undesirable material which enters the tube with the incoming water current. LITERATURE CITED BARNES, R. D., 1964. Tube-building and feeding in the chaetopterid polychaete, Spiochaetop- terus oculatHS. Biol. Bull, 127: 397-412. ENDERS, H. E., 1908. Observations on the formation and enlargement of the tubes of the marine annelid, Chaetopterns variopedatns. Proc. Indiana Acad. Sci., 1907 : 12S-135. ENDERS, H. E., 1909. A study of the life history and habits of Chaetopterus variopedatits. J. Morph., 20 : 479-532. MAcGiNixiE, G. E., 1939. The method of feeding of Chactopfcn/s. Biol. Bull, 77: 115-118. POTTS, F. A., 1914. Polychaeta from the northeast Pacific. The Chaetopteridae. With an account of the phenomenon of asexual reproduction in Phyllochaetopterus and the de- scription of two new species of Chaetopteridae from the Atlantic. Zool. Soc. London, Proc., 67 : 955-994. FACTORS AFFECTING FIREFLY LARVAL LUMINESCENCE 1 ALBERT D. CARLSON Dcpiirtnu'i/t of Biological Sciences, S/<itc University of A Yu r Yi<rk at Stony Brook, Stony Brook, AV-rc- York 117W The mechanism of control of the adult firefly flash, a burst of light lasting ap- proximately 02 second, has been studied intensively (Buck, 1948; McElroy and Hastings, l l <55 ; Me Kirov and Seliger, 1961 ; Buck and Case, 1961 ; Case and Buck. 1963; Buck. Case and Hanson, 1963; Smith, 1963). The larva does not produce a flash, but rather a uniform, structureless glow lasting for seconds (Dahlgren. 1917; Buck, 1948). Histologically its light organs represent a considerably sim- pler system because they contain no tracheal end cells, cells which are present in the adult light organ and implicated in flash control (Dahlgren, 1917; Snell, 1932; Alexander, 1943). When an adult firefly is subjected to falling oxygen concentration it remains dark for a short period. Then a dull glow spreads over the organ, gains in inten- sity, and then slowly declines to extinction. If air is readmitted during this "hy- poxic glow" a brilliant pseudoflash is produced, lasting 500 milliseconds or longer (Snell, 1932). The tracheal end cell valve theory of pseudoflash control, proposed by Snell and reaffirmed by Alexander (1943), implied that adult firefly lumines- cence was normally oxygen-limited and that the pseudoflash was independent of neural activity. Hastings and Buck (1956) also concluded that central nervou.s activity plays no part in the pseudoflash of the adult. Carlson (1961) examined the pseudoflash of the adult in more detail and implicated neural activity as well as hypoxia. In lampyrid larvae Buck (1948) and Hastings and Buck (1956) observed that low ambient oxygen induces an hypoxic glow and that subsequently increased oxy- gen tension elicits a pseudoflash, which resembles that of the adult. The present study of the larval pseudoflash response was initiated to determine in what respect the adult and larval pseudoflash differ. It was hoped the differences in turn could aid in elucidating the disputed role of the adult tracheal end cell in flash control. MATERIALS AND METHODS Larvae of the genus 1'holiiris were the- subjects of this study. They were collected in the early autumn and stored either in petri dishes on moistened filter paper at 4 C. or in dirt-filled dishes at room temperature. The experimental ani- mal was secured ventral side up on a narrow glass spatula provided with silver stimulating electrodes. The paired stimulating electrodes were usually positioned on each side of the ventral nerve cord in the sixth abdominal segment by insertion Supported by Grant-in-Aid 31-27 from the Research Foundation of the State Uuiversit\ i>t \c\\ York and 1>y a urant from tlu j National Science Foundation. 'SI KIRKFLY LARVAL LUMINESCENCE 235 through the intersegmental membrane between the sixth and seventh abdominal segments. The spatula was placed in the basal segment of a glass Y-tube which was 30 mm. long and 1 cm. in diameter. Oxygen and nitrogen were led into oppo- site branches of the Y-tube through paired two-way stopcocks which permitted rapid shunting of the oxygen from the animal. Gas mixtures were prepared from commercial compressed nitrogen and oxygen metered through two-stage reduction valves and calibrated Fishcher-Porter flow 7 meters. Composition was checked by gas analysis with a Scholander 0.5-cc. analyzer. Commercial compressed nitrogen, referred to hereafter as "nitrogen." was found to contain no more than O.OS/fc oxy- FIGURE 1. Stimulated glow and pseudoflash of Photuris larva. In this and all subsequent experiments except where noted : Upper trace is photomultiplier output ; middle trace heavy line is 21% oxygen and narrow line is nitrogen; marks on narrow segment are time base, 1 mark per second, reading from left to right. Lower trace : stimulus, 5 volts, 20 msec, dura- tion, 10 per second frequency. Electrode pair inserted in 6th abdominal segment in this and all subsequent experiments of larval light response. gen which was considered to be a negligible amount. A photomultiplier tube ( RCA 931-A) and dissecting microscope were positioned above the animal and both were shielded from stray light by black cloth. In preparation for a pseudoflash one valve was rotated 180 to shunt oft the oxygen and admit either nitrogen or a nitrogen-oxygen mixture. Rotation of this stopcock also opened a signal circuit. At an appropriate time the same valve was then rotated back 180 which allowed a higher concentration of oxygen to reach the animal suddenly and also closed the signal circuit. The pseudoflash was de- tected by a photomultiplier, the output of which was led to one or both channels of a Grass Polygraph. In some cases the amount of light recorded in a pseudoflash was obtained by integrating the light output with an integrating circuit utilizing a Philbrick operational amplifier. 236 ALBERT D. CARLSON RESI MS 1. dcncral characteristics <>\ larral //<//// responses The light induced in the larval organ by mechanically irritating the animal is variable in intensity and duration. An electrically stimulated response which mimics the mechanically induced light response is shown in Figure 1. A pseudoflash is also shown. The pseudoilashes of the larval and adult forms resemble each other more closely than do their respective natural light responses, which confirms the observation of I lasting and I'.uck ( 1956). The larval pseudoflash differs from the adult pscudoflash, which is illustrated in Figure 2 with a number of spontaneous flashes, in being more variable in duration and considerably longer, due to its in- creased decay period. Luminescence intensity is uniform over the larval lantern in all light responses. FIGURE 2. Spontaneous flashes and hypoxic j>lo\v followed by a pseudoflash in a I'liotuns adult male. Lower trace equivalent to middle trace in Figure 1. Hypoxic glow begins ap- proximately 7 seconds after hypoxic onset; note its relatively low intensity. Note lengthening duration of adult spontaneous flash as anoxia proceeds. 2. Effect oj electrical stimulation and o.\'v</en concentration on larra! light re- sponses Glow intensity in air is proportional to stimulation frequency up to approxi- mately 10 stimuli per second, above which no further increase can be produced. Induced glow intensity also varies directly with oxygen concentration between 0% and 10'.; oxygen as shown in Figure 3. \Yhereas the adult will produce a glow in nitrogen, the larva cannot be induced to glow in this gas after the initial 15 sec- onds of perfusion. During continual stimulation glows can be maintained for long periods in oxygen concentration as low as 0.25'/o and the glow level responds to rapid alternation of oxygen concentration. Larvae that have been glowing actively in air can produce pseudoflashes when the oxygen tension is manipulated, \on-glo\\-ing larvae must first be mechanically or electrically stimulated during the anoxic period before a pseudoflash can be produced by admitting oxygen. This .stimulation during anoxia need not elicit glowing to be effective in pseudollash production. Larvae left unstimulated for FIRKH.Y LARVAL LUMINESCENCE 237 periods up to 20 minutes in nitrogen failed to produce a pseudotlash upon re- admission of air, but would readily do so if stimulated during the anoxic period. Like the glow in air, the maximum intensity of the larval pseudoflash is also a function of stimulus frequency. It readies a maximum intensity at about 10 stimuli 8 12 16 20 24 OXYGEN CONCENTRATION (%) 28 FIGURE 3. Effect of oxygen concentration on the maximum glow intensity attained during stimulation in one Pliotiiris larva. Stimulus : 7 volts, 20 msec, duration, 10 per second fre- quency. Stimulation applied in various oxygen concentrations until a constant, maximum light intensity was attained. Recovery period in air was longer than 60 seconds. Oxygen concen- tration randomized during repeated experimental runs. per second when the animal is stimulated during a period in nitrogen, as shown in Figure 4. The total light output of the pseudoflash was closely related to its maxi- mum intensity. If stimulation is continued during readmission of air after hypoxia. an after-glow is produced on the falling phase of the pseudoflash, as shown in Fig- ure 5. Pseudoflash intensity is proportional to oxygen concentrations at least up 238 AU1KRT I). CARLSON to 21' i oxygen, as .shown in Figure (>. The pseudoflash shape can be changed into a multi-peaked response with rapid alternation of lQ f / ( oxygen and nitrogen; see Figure 7. 3. Effect of liypo.ua duration on pscHdofhish intensity \\'itli constant conditions of stimulation, pseudoflash intensity declines as the duration of hvpoxia increase^, as shown i" Figure S. T.ong hypoxic durations and 55 50 45 ^40 c o 35 >- 30 UJ 25 o 20 o Ul a 15 10 01234 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 STIMULUS FREQUENCY (stimuli /second) l-"i<,ri<K 4. ICtTcct nf stiinuln-. frcinK-iu-y during anoxia on pseudoflash intensity in J'lioturis larvai-. I'^arli p lint npivsuiK the mean pM'ii:lollasli intensity of 6 larvae except 2.5 stimuli per econd \\liich represents 4 larvae, liar-, indicate 2 standard errors. All intensities are rela live to the mean intensity ohlaiiK'd at 15 stimuli per second in the same individual in order to eliminate differences in M l ' c niftry "f light-collecting system. Stimulus frequency randomized during repealed experimental runs. Stimulus voita.^e constant lor each larva, 20 msec, dura- tion. Stimulation applied 5 .seconds after hypoxic onset for a total duration of 5 seconds. Ifypoxic duration 15 seconds. Recoverj perm.] l)et\\eeii pseudoflashes lasted 45 seconds; nitro- .'II used durinu hypoxic period and pseudoflashes induced with 21'- oxygen. FIREFLY LARVAL LUMINESCENCE 239 FIGURE 5. Effect of electrical stimulation prior to and during pseudoflash in Photnris larva. Lower traces stimulus, 4 volts, 40 msec, duration, 10 per second frequency. 36 r 32 - - 28 - 24 - 320 z x < o Q 3 UJ CO Q. 16 - 12 - 8 - 4 - 12 PERCENT OXYGEN 16 20 FIGURE 6. Effect of pseudoflash-inducing oxygen concentration on pseu loflash intensity in one Photnris larva. Stimulus 3 vo'.ts, 20 msec, duration, 10 per second frequency. Stimu- lation applied 5 seconds after hypoxia onset for a total duration of 5 seconds. Hypoxia dura- tion varied from 16 to 23 seconds. Recovery period between pseudoflashes was 1 to 2 minutes. Nitrogen used during hypoxic period. Oxygen concentration randomized during repeated ex- perimental runs. 240 ALBERT D. CARLSON their concoinitantly reduced pseudofiashcs did not affect the intensity of immedi- ately following pseudoflashes induced after .short hypoxia. I )ISCUSSION The similarities bet \\ecn the adult and larval pseudoflashes, with respect to induction se(|uence. response to electrical stimulation and response to oxygen con- centration, surest that both utilize the same basic process. In both developmental forms, the pseudoflush appears to be the result of an accumulation of light-producing substance and its rapid oxidation by the inrushing oxygen. _ I l- FIGURE 7. Effect of rapid alternation of 10% oxygen and nitrogen on the pseudoflash re- sponse of Plwtnris larva. Middle trace: heavy line. W< oxygen; narrow line, nitrogen. Lower trace: -timuhis, 4 volt-, 4(1 in-ec. duration. 10 per second frequency. Then- are a number of differences, however. between the responses ot the two forms. (I) Adults which are not Hashing immediately prior to anoxia can produce a pseudoflash without stimulation during the anoxic period. Non-glowing larvae must first be stimulated in some fashion during anoxia before a pseudoflash can be elicited. This might suggest that it is hypoxia alone which triggers the hypoxic glow in the adult. However, spontaneous neural activity invariably occurs prior to onset of the hypoxic glow in the adult, as observed by Carlson (1962). The need to stimulate the larva then perhaps reflects a relative lack of spontaneous neural activity. (2} The adult can maintain a glow in nitrogen for several minutes, indicating that oxygen is still available for the light reaction. The larva is apparently com- pletely deoxygenated within 15 seconds in nitrogen because stimulation induces no glow after that period as anoxia continues However, the anoxic larval photo- cytes are still responsive to electrical stimulation because stimulation initiated after the first 15 seconds of the anoxic period makes possible a pseudoflash upon re- admission of air. This difference in time necessary to flush out the oxygen during exposure to anoxic gas may be a reflection of the relatively more complex tracheal supply of the adult (Murk, TH<S). If this assumption is correct the observation FIRFFLY LARVAL LUM1XES' 241 that the larval pseudoflash occupies, on the average, about six times the duration required for the adult pseudoflash cannot be explained on the basis of oxygen diffu- sion rates to the photogenic tissue. If diffusion rate controlled pseudoflash dura- tion one would expect the adult pseudoflash to lie of longer relative duration due to > 14 i D 6 o 20 40 60 80 100 120 HYPOXIC DURATION (seconds) 140 ISO FIGURE 8. Decline of pseudoflash intensity with increasing hypoxia duration under con- stant conditions of stimulation in one Photuris larva. Stimulus : 6 volts, 4 msec, duration and 10 per second frequency. Stimulation applied 15 seconds after hypoxia onset for a total duration of 2 seconds. Recovery period between pseudoflashes was 60 seconds; nitrogen usrd to produce hypoxic period and pseudoflashes induced with 21% oxygen. First point is average of 34 measurements; line shows total range of values for that point. the evident impediment to oxygen diffusion noted in its resistance to deoxygenation. The explanation for the differences in pseudoflash duration between the two forms must lie, therefore, at another level in the luminescence process. (3) As illustrated in Figure 2, as anoxia proceeds the adult spontaneous flashes decline in intensity and increase in duration and then are replaced by a low level glow. Further, this shift from flash response to hypoxic glow fails to develop above an oxygen concentration of about 2.5%; instead the adult can continue to produce 242 ALBERT I) CARLSON small, spontaneous or electrically driven flashes (Hasting and Buck, 1950). The lar\al glow shows no such discontinuity but is simply proportional to oxygen con- centrations below 10'. r under uniform stimulus conditions. One might explain these differences on the basis that the larval glow and the adult hypoxic glow are similar phenomena in that they represent processes which are oxygen-limited. Above about 2.0% oxygen, however, another limiting process may be superimposed upon the light reaction in the adult which results in a flash response. This non- oxygen-limiting process may involve the tracheal end cell or may be due to im- portant biochemical differences within the photocytes of the larval and adult forms. There is no comparable experimental evidence that the inactivation of light- producing .substance by non-luminescent means, which may occur in the larva during anoxia, also occurs in the adult. Long anoxic durations, which apparently result in a large inactivation of substance by some dark reaction in the larva, do not preju- dice the intensity of later pseudoflashes induced with shorter anoxic periods. It would appear that this non-luminescent inactivation of light-producing substance Iocs not prevent reactivation for use in subsequent flashes. SUMMARY 1. Electrically stimulated light responses and pseudoflashes were studied in larval fireflies, Photitris sp. 2. The larxal pseudoflash is highly variable, but it is considerably longer in dura- tion than the pseudoflash produced by the adult. 3. Larvae which were not previously glowing in air would not produce pseudo- Hashes unless stimulated during the anoxic period prior to admission of oxygen. Even with stimulation no glow could be produced in nitrogen. Pseudoflash inten- sity is proportional to stimulus frequency up to 10 stimuli per second. Light in- tensity is dependent on oxygen concentration up to 10% oxygen under uniform stimulus conditions. A multipeaked pseudoflash response can be obtained with rapid alternation of 10% oxygen and nitrogen. 4. Pseudoflash inten.sity declines with increasing hypoxic duration under uni- form stimulus conditions. 5. Differences between the larval and adult pseudoflash response are discussed, but no difference could be linked directly to the operation of the adult tracheal end cell. LITERATURE CITKD AI.EXAXDKR, KOHERT S., l c '43. Factors controlling firefly luminescence. /. Cell. Camp. Plivsiol., 22: 51-71. PIIVK, JOHN B., 194S. The anatomy and physiology of the li.nlit or.uan in fireflies. .Inn. N. V. A cad. Sci.. 49: 397 482. II it K, JOHN, AND JAMES F. CASK, 1961. Control of flushing in fireflies. I. The lantern as a neurocftYctor or.<;an. />/'/. Hull., 121: 234 256. III i i.. JOHN, JAMES F. CASE AND FKAXK F. ll.\xsn\, JR., 1963. Control of flashing in fire- flies. III. Peripheral excitation. Biol. Bull., 125: 251-269. CARLSON, AI.BKKT I)., 1961. Effects of neural activity on the firefly pseudoflash. />/'(>/. Hull., 121 : 265-276. RLSON, AI.ISEKT D., 1962. Neural activity during hypoxia in adult firefly. />'/<>/. />';///., 123: 490. FIKKFLY LARVAL LUMINESCENCE 243 CASE, JAMES F., AND JOHN BUCK, 1963. Control of flashing in fireflies. II. Role of central nervous system. Biol. Bull., 125: 234-250. DAHLGREN, ULRIC, 1917. The production of light by animals. /. Franklin fust., 183: 323-348. HASTINGS, J. WOODLAND, AND JOHN BUCK, 1956. The firefly pseudoflash in relation to photo- genic control. Biol. Bull., Ill: 103-113. McELROY, W. D., AND J. W. HASTINGS, 1955. Biochemistry of firefly luminescence. Pp. 161- 198. /;/: Luminescence of Biological Systems (Ed. F. H. Johnson), Amer. Assoc. Adv. Sci., Washington. MrEi.ROY, W. D., AND H. H. SELIGER, 1961. Mechanisms of bioluminescent reactions. Pp. 219-257. In: Light and Life (Ed. by William D. McElroy and Bentley Glass), The Johns Hopkins Press, Baltimore. SMITH, DAVID S., 1963. The organization and innervation of the luminescent organ in a firefly, Photuris pciuisylrauicd (Coleoptera). /. Cell Biol.. 16: 323-359. SNELL, PETER A., 1932. The control of luminescence in the male lampyrid firefly, Phutitris pennsylvanica, with special reference to the effect of oxygen tension on flashing. /. Cell. Comp. Physinl., 1 : 37-51. THE MECHANISM OF THE SHADOW REFLEX IX CIRRIPEDIA. 11. PHOTORECEPTOR CELL RESPOXSE, SECOND-ORDER RKSroXSKS. \XI) MOTOR CELL OUTPUT 1 <;. K <;\YIU.IAM Department ,>f Biology, Reed Colleuc, Portland, Orcuon ''/"Jrf'J. and the Marine Biological /.ahomtory. U'onds Hole. Muss. 02543 In a previous report ((iwilliam, 19(>3), certain electrical events at various locations in the nervous system of cirripedes, associated with changes in the light level impinging upon a photoreceptor, were described. At that time it was sug- gested that the photorece])tor cells have axons that do not synapse until reaching the supraesophageal ganglion, and that these cells influenced the activity of the second-order neurons by passive electrotonic conduction of a depolarizing poten- tial which occurs when the photoreceptor is illuminated. Recent evidence from electron microscopv ( Fahrenbach. 19o5 ) supports this suggestion from a structural point of view, and observations to be reported here lend functional support. Recent papers on the structure of the crustacean nauplius eye (Kauri. 1962; Elofsson, l' 1 ')^! indicate that it is made up of three components, and the evidence presented here that adult balanid barnacles possess three (paired lateral and single median) photoreceptors suggests that they may well be derived from the three- parted naupliar eye found in the larvae of Bahiiins (Kauri. 1962). \Yhile it ap- pears that the detailed structure of the three "compartments" of the larval medial eye does not coincide with that of the presumed separated components of the adult photoreceptors, the mere existence of three distinct components indicates a possible developmental source of the three adult photoreceptors. In addition, further information has been obtained on neural pathways from the ocelli to certain of the muscles responsible for the withdrawal-closure response to a shadow that is so characteristic of most barnacles. A I. \TKKJALS AND METHODS Three species of barnacles have been used in this study. Balanus eburneus ( lould was used for the intracellular recording, and the animals were supplied by the Supply Department of the Marine Biological Laboratory, Woods Hole, Mass. Other observations were made on specimens of Bahnins tintinnabulum (L.) and ttahnius cariosus (Pallas). The former were supplied by Dr. Eric Barham, Xavy Klectronics Laboratory. San Diego, California, and Dr. James Case, University ot California. Santa I'.arbara. The latter were collected by the author from the north central Oregon coast. The lateral eyes of I>. clninicns were exposed by splitting the shell along the longitudinal ( rostrocarinal ) axis, carefully removing the opercular valves with the ipportrd by a tyrant to thr author ((,-l 3l ( h from the National Scienrc Foundation. \ critical reading of the manuscript by J)r. Harold 1',,-inic-, U ratrlully acknowledged. 'I I THE SHADOW REFLEX IN CIRRIPEDIA 245 body of the animal attached, leaving two "half-shells," each of which bears a lateral eye and a short length of retinula cell axons. The eye is located at the junction of the fused rostrum-rostrolateral and lateral shell plates and is easily visible with the naked eye. These "half-shells" were then mounted, inner surface up. with soft wax, in the recording chamber. The pigmented mantle over the photo- receptor was then dissected away, and the capsule of the tapetum or reflecting layer was removed. This permitted direct viewing of the photoreceptor cells, which appeared as two orange-yellow areas in each eye, although histological examination reveals three cells. Xext, the preparation was treated with trypsin (X 300), 80 mg./lOO ml. of sea water, for 45 minutes. Following this treatment, penetration with the micro- pipettes could be accomplished in many preparations. Attempts to penetrate cells without enzymatic pre-treatment were never successful. Glass micropipettes filled with 3 .17 KC1. having a resistance of 10-15 megohms in sea water, served as electrodes. The amplifier used was an Argonaut "nega- tive capacitance electrometer" which fed into a Tektronix type 502 dual beam oscilloscope. Other recording techniques, the control of light to the preparation, and the making of permanent records are described elsewhere (Gwilliam, 1963). Light intensity is referred to as "unit intensity" or "intensity one" or a percentage of unit intensity achieved with neutral density filters. Unit intensity was approximately 1,000 foot-candles at the preparation. The preparation used for external recording was achieved in the following manner: The opercular valves, bearing the body of the barnacle, were dissected free from the shell. This was then placed in a wax-lined dish, opercular plates down, and a pin thrust through the median junction of the apex of the scuta. The body was then extended along the longitudinal axis away from the terga and pinned. This exposed the mouth and ventral surface, brought the adductor muscle into view, and made dissection of the median photoreceptor, supraesophageal gan- glion, and circumesophageal connectives relatively simple. In this position the lat- eral photoreceptors are found beneath the body of the animal close to the scutal margin just to either side of the mid-line in B. tintiniiabulitin, but would not be in- cluded in the preparation in R. cburncns, for in that species the eyes are displaced more basally and laterally onto the shell lining (see above). The supraesophageal ganglion must be exposed by dissection, which then makes it possible to locate and identify the circumesophageal connectives, the antennular nerves (which contain the lateral ocellar axons) and the suprasplanchnic nerves. The area overlying the adductor muscle may be dissected away, which exposes the median ocellus and its nerve, the adductor muscle itself, and the great splanchnic nerve, with its adductor muscle motor branch. Further, one can expose the ventral ganglion and the cirral nerves to make the latter accessible for recording motor output. All this can be done without disrupting the circuit as illustrated in the diagram (Fig. 1 ), so that it is possible to record at any one site and remove sensory input as desired. Thus, one can record from cirral nerves or adductor muscle motor nerves with the rest of the system intact, cast a shadow, observe the effect, and then cut either the lateral or median ocellar nerve and again observe the effect of a shadow. The same procedure can be followed when recording from the circum- 246 (l . ]. , ,\\ ILLIAM esophageal connectives, 1ml as it is necessary to cut them close to the ventral ganglion for recording, it would no longer IK- possible to record responses to shadows in cirral nerves or in the adductor motor supply. RESULTS Structure After dis.section as described almve. the terga and the scutal apex would he at the bottom of Figure 1. \\ith the- cirri extending from the top. The general body surface viewed is morphologically the ventral surface. In most cases the median ocellar nerve can be seen through the thin, usually non-pigmented exoskeleton, and the "ophthalmic ganglion" of Darwin (the median photoreceptor) can sometimes be seen King very close to the adductor muscle, at which point it is attached. It is also usuallv possible to see the great splanchnic nerve which originates on the dorsal aspect of the ventral ganglion, runs out laterally to the scuta, and gives off a motor branch that supplies the adductor muscle. The diagram in Figure 1 is based on B. tintiniiabitluin, the same species illus- trated by Darwin ( 1S54, PI. XXVII, Fig. 2), hut apart from differences in orienta- tion of the two figures, one significant difference should be noted. Darwin as- sumcd (but did not actually see) a connection between the lateral ocelli and what he called the ophthalmic ganglion (the median photoreceptor of Figure 1 ) which I cannot find. It is clear that the lateral ocellar axons enter the supraesophageal ganglion independently of the median ocellar nerve, since severing the median ocel- lar nerve at the supraesophageal ganglion does not interfere with responses to shadows in the rest of the .system as long as the antennular nerve is intact. In a previous paper ( ( i\\ illiam, 1963), I stated that the median photoreceptor was probably the onlv one present in B. cariosus, and that it was onlv occasionally functional as a photoreceptor in B. cbitrncns. I am now convinced that both of these statements are in error, for lateral photoreceptors can be demonstrated physi- ologically in B. airiosus, if care is taken not to cut too close to the scuta when dis- secting the opercular plates free. The small size of B. cbunicits and consequent difficulty in dissecting make it likely that previously the median ocellar nerve was damaged in many preparations of that species. These new observations, and the fact that B. tlntitinabnlnui, B. baluints, B. cre- iiatns and B. hdhnioidcs all possess both lateral and median ocelli convinces me that all balanids probably conform to the pattern illustrated diagrammatically in Figure 1. but that the lateral ocelli are better developed and more obvious in some than in others. B. churncns and /!. nnipliilritc are similar in having obvious, pigmented lateral ocelli in the position described for B. chiimcus by Fales (1928). In B. tin- tnnntlntlniii, B. Ixi/iinns and l>. crcnntns they are not so obvious and lie closer to the mid-line, just inside the margin of the scuta in the opercular membrane. In B. ruriosiis and B. bahnioidcs the lateral ocelli have not been seen, but can be physi- ologically demonstrated to occupy a position similar to that in the last three species mentioned. The structure of the photorn ,-ptors themselves is reported by Fahrenbach (1965) for the median ocellus of B. cariosus and, in less detail, for the lateral ocelli of /,'. (iiupliitriic which are virtually identical to B. chiinicus. Fales (1928) reports two large photoreceptor cells in each lateral eye of B. ebnrncus, but there are in THE SHADOW REFLEX IN CIRRIPEDIA 247 fact three (based on examination of serial sections of B. eburneus lateral ocelli). In both the median and lateral ocelli examined, there is no ommatidial organization, and no evidence of a synaptic layer close to the ocellus. The cell bodies ha\e finger- like "dendritic"' projections \\h!ch lu-ar the micnnilli, and each soma has a large axon that apparently does not synapse until the level of the supraesophageal gan- glion. The size of the axons (15-20 /A in diameter i and the nature of the glial Cirral nerve 2-6 Lateral photoreceptor Antennular nerve Cirral nerve 1 Circumesophageal nerve Supra-esophageal ganglion Great splanchnic nerve ( \ Median photoreceptor Scutum FIGURE 1. Diagram of the balanid central nervous system, showing the relationship of the photoreceptors to it. Based on B. tintiniuilnilum. Details of branching in the antennular nerve are schematic and are included simply to indicate that the nerve is mixed. sheath around the ocellar nerve suggest a high value for the length constant of the axons. Electrical activity (a) Balaims eburneus: intracellularly recorded responses Although direct proof of penetration of photoreceptor cells is lacking, it was assumed \vhen a maintained negative potential was recorded. Further, only those preparations which showed reversible depolarization when exposed to a light flash 248 i , I ,\\ IU.IAM \\rre assumed to have been successfully impaled. Such cells could often be held for as long as three hours, hut relatively few such preparations were obtained. In the limited time available, only ;i total of twelve preparations met the above criteria for any significant length of time. F IMM-RE 2. Intracellular records from the lateral photoreceptor cells of Balanus cbnrncits. Inset time calibration applies to \\ through M; voltage calibration applies to all records. In tin- figure and all other-,, upward deflection of the second beam indicates "on." A, sustained response. B and C, the response to a 0.8-sec. light flash, B at a lower intensity than C. D, response to a flash of unit intensity. [:. 1.0% unit intensity. F, 0.1% unit intensity. Photo- cell failed to record in I 1 ', and K. G-K, Decreasing time series. L. The membrane potential at the close of the time scries. M, the effect of a light flash on the removed electrode. In such cells, membrane potentials recorded varied considerably, depending on the immediate history of the penetrated cells. Initial membrane potentials recorded on penetration while viewing in relatively bright light were on the order of 30-45 mV, inside negative. After one hour in darkness these approached 60-70 mV. The wave-forms of the potentials recorded when the preparation was exposed to a (lash of light are shown in Figure 2. This consists of the familiar "on" transi- ent, often, but not always, a secondary rise, followed by a maintained level of de- polarization. At "off" this drops very close to the original membrane potential level ( Fig. 2. A, B, C). Amplitude of the generator potential was graded in dif- ferent light intensities (Figure 2, D, E, F), and the transient disappeared at low intensities. The wave-form also varied in light flashes of intensity one, but of THE SHADOW REFLEX IN CIRRIPEDIA 249 different duration (Fig. 2, G-K). In this case only the transient remained in flashes less than 0.5 second in duration. At the highest intensity the transient may overshoot zero potential, but this could not be determined with certainty, because of the shifting membrane potential dependent on previous exposure to light (cf. Naka, 1961 ; Naka and Eguchi, 1962a ) and to the D. C. drift in the amplifier. However, in a dark-adapted preparation, the transient seldom exceeded 55 mV, which suggests that overshoot did not occur if membrane potentials reached the values of 60-70 mV which were recorded in other cells after dark adaptation. It will be noted that these intracellular responses are very similar in form to the presumed intracellular response from the median eye of B. cariosits as previ- ously reported (Gwilliam, 1963, p. 476) and very similar to the simple electro- retinograms recorded from barnacle ocellar nerves, if the difference between A. C. and D. C. recording is taken into account. That is, the extracellularly recorded "mass" response is directly comparable to the single unit intracellularly recorded response, both being almost certainly uncomplicated by post-synaptic events. Under the conditions of the observations reported here, it seems highly unlikely that the "on" transient has its source in other than the impaled retinula cell. The photoreceptor consists of three primary receptor cells, supporting cells, and very little else. There are no nearby post-synaptic cells to contribute, so the suggestion that the "on" transient originates elsewhere (Burkhardt and Autrum, 1960; Burk- hardt, 1962) seems to be ruled out in this material. As Ruck (1964) points out, the recorded amplitude alone of the transient argues very strongly against its origin outside the retinula cell. The records are also uncomplicated by anything resembling ordinary spikes. This is also true of the ocellar-nerve recorded ERG when the bundle is uncontami- nated with other nerve fibers. There is thus no evidence that the retinula cell axons conduct ordinary spikes, despite the relatively great distances over which they pre- sumably transmit. It may be argued that in the illustrated cases the photoreceptor cell axons have been damaged in the exposure procedure, and that this could in turn destroy the spiking locus. However, if the "on" transient is accepted as an axonal event, its presence in these records argues against extensive axonal damage. It might also be argued that the light levels used are insufficient to operate the spiking mechanism, but the same light levels serve to inhibit firing of cells in the supra- esophageal ganglion, proving that they are adequate to operate the normal post- synaptic inhibitory mechanism that leads to the shadow reflex upon release. The suggestion put forth by Ruck (1964) that the transient may be a regenera- tive event has not been adequately tested in this material, but as Ruck himself points out, this will not account for sustained transmitter action on post-synaptic cells. ( b) External recording in B. tintinnabulum and B. cariosus 1 . Lateral vs. median photoreceptor function Having established that two morphologically distinct sets of photoreceptors ex- isted, I tried to discover if they had different functions. The records reproduced in Figure 3 illustrate the results of observations on the two species. Figure 3, A 250 G. F. r, WILLIAM illustrates a circumesophageal connective recording of the results of a shadow cast on a preparation of B. cariosus with both sets of photoreceptors intact. Figure 3, B was taken from the same preparation after severing the median ocellar nerve, and Figure 3, C after severing both antennular nerves. Figure 3, D is from a dif- ferent preparation of the same species, the electrode recording from the motor FTGFRF. 3. Function of the lateral and median eyes in />'. luriasits (A-K) and />'. tintinnabulum ((J-K). See text for explanation. supply to the adductor muscle, with both sets of photoreceptors intact. Figure 3, E is from the same preparation with the antennular nerves severed, and in Figure 3, F the median nerve has been M-vered as well. These records prove the existence of lateral photoreceptors in B. cariosus, estab- lish that both sets are capable of mediating the shadow reflex, and suggest that there is no difference in function between the lateral and median photoreceptors in this particular pathway. THE SHADOW REFLEX IN CIRRIPEDIA 251 Figure 3, G is a circumesophageal recording from B. tintinnabulum with both sets of eyes intact; in H, the antennular nerves have been cut; and in I, the median nerve was also severed. Recordings from the adductor motor supply give the same results as in B. cariosns. These records, also, indicate that there is no difference in function of the two sets of photoreceptors in B. tintinnabulum. Figure 3, J and K were obtained from the cut ends of the nerves containing the photoreceptor axons. J is a record of the lateral ocellar ERG taken from the cut end of the nerve close to the supraesophageal ganglion, while K was recorded from the same relative position from the median nerve. Both records were taken at the same overall gain and band pass frequency (0.3-2000 cps) and at the same dis- FIGURE 4. Series to illustrate different rates of adaptation to multiple stimuli at different points in the responding system. Upward deflection of upper beam in A and lower beam in F indicates positivity of active electrode. Membrane potential in F (indicated by the initial sepa- ration of the two beams) 60 mV. In F, downward deflection of upper beam indicates "off." tance above the bathing medium. The difference in amplitude, rise and decay times in the two records may reflect the greater distance of transmission of the lat- eral ocellar axons (Fig. 3, J) and probably illustrates the decremental nature of ocellar axon transmission. It should be pointed out at this juncture that the initial deflection of the ERG when recording externally from the ocellar nerve at some distance from the photo- receptor with a single active electrode is positive in sign rather than negative as erroneously reported in Gwilliam (1963). If the record is taken just distal to, or from the region of the photoreceptor cells, the sign is reversed. This result then accords with other arthropod ocelli in which the ERG is cornea-negative and retinula cell axon-positive when recorded extracellularly, as shown by Ruck (1961) and others. G. F. GWII.LJAM 2. The response to multiple slun: Gwilliam (1963) briefly reported that the response to multiple shadows at different points in the photoreceptor-motor output chain showed different rates of adaptation. This was investigated more fully in B. tintinnabulum and B. cariosus. two species obtained from rather different habitats and showing different behavioral reactions to multiple shadows. The similarities and differences between the two species are illustrated in Figin Figure 4, A illustrates the non-adapting nature of the ERG in B. cariosus, and identical records have been obtained from B. tintinnabulum. Figure 4, B is a record of a circumesophageal recording from B. tintinnabulum which illustrates that at this point (the presumed .second-order neurons) adaptation is very slow, but will fail to follow after approximately 30 shadows of the duration and frequency shown. A very similar phenomenon can be demonstrated in the circumesophageal connective of B. cariosus. Similarly, the motor output to the cirri in B. tintinnabulum adapts very slowly (Fig. 4, C), but the cirral output in B. cariosns adapts very rapidly. often failing to follow even after a single shadow (Fig. 4, D ) , and seldom persisting for more than four shadows. In both species the motor output to the adductor muscle fails to follow after 1-4 shadows (Fig. 4, E of B. cariosits). Figure 4, F is a record of an intracellular response of one of the giant muscle fibers from the adductor muscle in B. cariosus and illustrates the effect of a burst of motor nerve action potentials on the muscle junctional potentials ( rf. Fig. 4, E) in re- sponse to a shadow. If one now turns to an intact, feeding animal and presents shadows of the same duration and frequency used in the neurophysiological work, the behavior of each species corresponds to the pattern seen in the records of Figure 4. B. tintinnabulum will respond by withdrawal of the cirri and valve closure (ad- ductor muscle contraction) to the first shadow. If shadow-casting is continued, the animal very quickly emerges, but continues to withdraw the cirri at each shadow, but after one or a few additional shadows fails to close the valves. B. cariosus, on the other hand, responds to the first shadow, quickly re-emerges and. after one to four additional shadows, proceeds to execute "fishing" activities. completely ignoring the changing light level. These responses, of course, will occur in this particular way only in the ab- sence of any reinforcing stimuli such as mechanical shocks, or tactile stimuli. If the shadow is accompanied by a tactile stimulus or a blow to the dish containing the animals, they remain closed for much longer periods of time and do not adapt to the dual stimulus nearly so quickly. While this difference in behavior is difficult to explain with any degree of confi- dence, it is interesting to note that the B. cariosus used in this study were collected from the outer Oregon coast \\here the wave action may be severe, and the water frequently contains much floating and suspended debris. B. tintinnabulum, how- ever, was collected from harbor floats and pilings in relatively quiet bays in south- ern California. In the two dilTerin- situations, it may be that a shadow is a more "urgent" stimulus in quiet water (i.e., more frequently signals the 1 approach of a predator), and continued response is of significant value to the species. In more turbulent waters, where shado\\s i|iiiit often signal onlv a piece of floating debris. the response may be less significant. THE SHADOW REFLEX IN CIRRIPEDIA 253 DISCUSSION The information now available on the structure and function of the adult bar- nacle photoreceptors and the nervous system permits a resume which represents a fairly complete description of, at least, the obvious pathways and events that are involved in the shadow reflex. In no case has the response chain, from photo- receptor cell membrane depolarization to muscle junctional potentials, been followrd completely through in one species, but by combining information from several it is possible to reconstruct the probable chain of events. It now seems highly probable that all balanid cirripedes possess two distinct sets of photoreceptors : a pair of bilaterally symmetrical lateral ocelli and a single me- dian photoreceptor "ganglion." That these receptors contain retinula cells with typical arthropod rhabdomere microvilli is now established, and the absence of a synaptic layer close to the retinula cells is strongly indicated (Fahrenbach, 1965). It is generally held that the adult cirripede eye(s) takes its origin from the me- dian eye of the nauplius larva (e.g., Doochin, 1951), and the structure of that eye in the larva of Balanus suggests the developmental source of the three separated photoreceptors found in the adult. While a detailed comparison of the structure of adult and larval eyes (Kauri, 1962; Fahrenbach, 1965) reveals considerable difference in numbers of sensory cells and their organization, the existence of three components in the larva is very suggestive. It should be recognized that many larval structures do not develop directly into adult structures but emerge as the definitive adult structures following a phase of larval "degeneration" (Bernard and Lane, 1962). To judge from the location and structure of the two sets of "eyes" in an animal like B. eburneus, it would seem that the median photoreceptor receives light most easily when the animal has the opercular valves open and the cirri extended. How- ever, it must be recognized that an actively "fishing" barnacle probably casts shadows on its own median photoreceptor, which suggests the existence of inhibi- tory feed-back mechanism to prevent withdrawal reactions during this process. In the lateral photoreceptors of B. clntnicns, the location of light-absorbing and reflecting pigments over the inner surface of the PR cells makes it apparent that they must receive light either parallel to the shell plates and/or from the outside. In an animal like B. tintinnabulum this may also be true, but the inner shielding is less well developed. Very little can be said about B. cariosus lateral eyes, for the structure has not yet been morphologically identified. The structural information on the retinula cells provided by Fahrenbach (loc, cit.} helps a great deal in explaining the absence of propagated action potentials in barnacle retinula cell axons. The large size of these axons ( 15-20 /x diameter) contrasts markedly with those of, for example, the cockroach dorsal ocellus which averages 0.5 ^ (Ruck, 1964). Also, the inter-axonal space which is filled with glial cell membrane is quite large, so that in contrast to the cockroach, the length constant of barnacle retinula cell axons is probably quite large. It thus appears that a structural basis for long-distance electrotonic conduction is present. The function of these photoreceptors seems to be primarily that of initiating the shadow reflex, although other functions may also be imagined. Structural consid- erations rule out any image-forming capabilities, and it seems evident that the "eyes" are relatively simple light-level and transient-photic-event monitors. No 254 G. F. GWILLIAM difference in function of the lateral and median photoreceptors is so far apparent with the techniques used in this study, but more subtle functional differences are not precluded. In a purely speculative manner, one might imagine the sequence of events lead- ing to a shadow reflex as occurring in the following way: self-cast shadows on the median photoreceptor would cause a certain amount of depolarization in the second order neurons at "off." In an immobilized preparation this would be sufficient to trigger the reflex, but in a "fishing" animal this would be countered by inhibitory neurons (acting on the same second-order cells) activated by the body movements. The balance between these two processes and the inhibitory influence of the illumi- nated lateral photoreceptors would serve to keep the second-order cell membrane potential depressed below the firing level. If, during this process, the added de- polarization (release from inhibition) furnished at "off" by the lateral photorecep- tors should impinge on the second-order neurons, the firing level would be reached, which would operate the withdrawal-closure reflex; this would in turn shut off the inhibitory feed-back mechanism and keep the animal contracted until the shadow- was removed, or until firing in the second-order cells ceased (a matter of approxi- mately 30-60 seconds ) . That there are distortion-sensitive sensory cells present in the mantle lining close to the body can be demonstrated by stretching the mantle while recording from the cut end of the antennular nerve, the same nerve that carries the lateral photoreceptor axons. The spikes shown in Figure 10 (page 482) of the previous paper (Gwilliam. I'^o ) are almost certainly in this category. Whether or not they inhibit the same second-order cells or the motor cells involved in the shadow- reflex is not known. Hoyle and Smythe (1963) have been unable to demonstrate peripheral inhibition in barnacles, but central inhibition certainly occurs. However, the chain of events as demonstrated to date suggests the following interpretation : (a) The photoreceptor cells generate a sustained depolarizing potential when illuminated. (b) This potential is transmitted by passive electrotonic conduction ria the large retinula cell axons to the supraesophageal ganglion where the axons synapse with the second-order neurons. (c) The sustained depolarization probably causes the continual release of an inhibitory tran>n litter substance from the terminations of the retinula cell axons which prevents the second-order cells from firing, although inhibition may be ac- complished by some other mechanism. (d) At "off," the inhibition is released and the second-order cells begin to fire. (e) The second-order cells synapse either directly or through other interneurons in the ventral ganglion with motor neurons. At this level the post-synaptic event is excitatory. (f) At this level, rather than the previous one, the phenomenon of synaptic failure (seen as a failure of motor neurons to respond to multiple stimuli) probably occurs. This "tendency to failure" varies in different species and in different motor cells of the same species. It thus appears that the barnacle retinula cell behaves in a very similar fashion to the retinula cell in the insect dorsal ocellus i Ruck. 1962, for summary), the THE SHADOW REFLEX IN CIRRIPEDIA 255 striking difference being the greater distance between the retinula cell and the first synapse. This has apparently been compensated for in the barnacle by the morpho- logical specializations referred to previously rather than by the development of an impulse-propagating mechanism. It seems quite plausible to argue that this mode of transmission is fundamental to arthropod photoreceptor cells, and the existence of a spiking mechanism (Naka and Eguchi, 1962b) represents a high degree of specialization. Washizu (1964), recording intracellular potentials from blowfly compound eyes, detected no impulse activity and demonstrated that the "on" transient did not overshoot zero potential and was graded. Unequivocal evidence of propagated impulse activity in retinula cell axons, on the other hand, is very limited. SUMMARY 1. The gross structure of the balanid central nervous system and some of the peripheral structures involved in the shadow reflex are described and figured (Fig. 1 ) . The existence of both paired lateral and single median photoreceptors in sev- eral species of barnacles is established, and is probably true for all balanid cirripedes. 2. Intracellular sensory potentials from the lateral ocelli of B. eburneus indicate that spiking does not occur in these retinula cells, and that the wave form of the response to a light flash is very similar to comparable records from other arthropod retinula cells. 3. No significant difference between the function of the lateral and the median ocelli has been shown with the procedures used in this study. 4. The different rates of adaptation of neurons in the reacting chain have been studied. The primary sensory event is non-adapting, the presumed second-order neurons adapt very slowly, as does the cirral motor output in B. tintinnabulum. The cirral output in B. cariosns, however, adapts rapidly, and so does the adductor muscle motor output in both species. This difference in motor output correlates very well with the behavior of intact animals. 5. The probable chain of events leading to the withdrawal-closure response to a shadow is summarized. LITERATURE CITED BERNARD, F. J., AND C. E. LANE, 1962. Early settlement and metamorphosis of the barnarlr Balanus amphitrite nivcus. J. Morph., 110: 18-39. BURKHARDT, D., 1962. Spectral sensitivity and other response characteristics of single visual cells in the arthropod eye. Symp. Soc. E.rp. Bin!., 16: 85-109. BURKHARDT, D., AND H. AUTRUM, 1960. Die Belichtungspotentiale einzelner Sehzellen von Calliphora erythrocephala Meigen. Z. Naturforsch., 15b: 612-616. DARWIN, C., 1854. A Monograph on the Subclass Cirripedia. The Balanidae (or sessile Cirripedes) : the Verruddae, etc., etc., etc. London. The Ray Society. 684 pp. DOOCHIN, H. D., 1951. The morphology of Balanus improvisns Darwin and Balanus amphitrite nircns Darwin during initial attachment and metamorphosis. Bull. Mar. Sci. Gulf and Carib., 1: 15-39. ELOFSSON, R., 1963. The nauplius eyes and frontal organs in Decapoda (Crustacea). Sarsia, 12: 1 68. FAHRENBACH, W. H., 1965. The micromorphology of a simple photoreceptor. Zeitschr. ZcH- forsch., 66: 233-254. FALES, D. E., 1928. The light receptive organs of certain barnacles. Blol. Bull., 54: 534-547 G. F. GY\ il.l.lAAl (iwn.i.iAM, G. P., 1963. Tlu- mechanism idow rcilcx in Cirripedia. I. Electrical ac- tivity in the supraesophai;ral ganglion and ocellar nerve. >w/. /?//.. 125: 470-485. HOYLE, G., .\\i T. SMYTHS l ( '(o. XetiromiiM-ular physiology of giant fibers of a barnacle, Helmuts inthilits Daruin. i ^;;;/>. l>it>chcm. Physiol., 10: 291-314. KATRI. T.. 1962. On the I'mnta! tilanieiits and nauplius eye in Balanns. Cnistacenitti. 4: 133 142. NAKA, K'.-l.. 1 ( .'()1. Ixecnrdin.u a\ retinal action potentials from single cells in the insect com- pound eye. J. Gen. 1'liysiol., 44: 571-584. XAKA, K.-l., AND E. Ecucin. l ( '';2a. l-'.i't'ect of background illumination on the retinal action potential. Science, 136: 877-87''. NAKA, K.-l., A\I> E. EGUCHI, 1962h. Spike potentials recorded from the insect photoreceptor. /. Gen. Physiol., 45: 663 680. Ki ' K, I'., 1961. Electrophysiology of the insect dorsal ocellus. I. Origin of the components of the electro-rctinogram. /. </V;;. Fliysiol., 44: 605-627. Kvi-K. P., 1962. On photoreceptor mechanisms of retinal cells. Biol. Bull., 123: 618-634. Rtvk. I'., 1"')4. Krtinal structures and photoreception. shin. Rev. Entoin., 9: 83-102. W \sinzu, Y., 1964. Electrical activity of the single retinula cells in the compound eye of the l>'o\vfly Ciilliplior,! grythrocephalct Meigen. ('<u;;/>. Biochcm. Pliysiol., 12: 369-387. OBSERVATIONS ON THE NUTRITION OF MONOGENETIC TREMATODES D. W. HALTON ' AND J. B. JENNINGS J >i'ptirtmcnt of Zoology, The (Jni-rcrsity of Leeds, England Relatively little information is available regarding the general pattern of nutri- tion in the Trematoda Monogenea, but there are indications that the two sub-orders of this class of parasitic flatworms differ considerably as regards the nature of their diet. The Monopisthocotylea so far investigated are reported to feed on the epi- dermal tissues and associated secretions of the host organism, whilst the Polyopis- thocotylea appear to be largely sanguinivorous and take in little host tissue other than blood (Goto, 1895; Heath, 1902; Folda, 1928; Gallien, 1934; Sproston, 1945; Llewellyn, 1954; Jennings, 1956, 1959; Uspenskaya, 1962; Kearn, 1963). Other differences between the two sub-orders, concerned with nutrition, are seen in the cellular structure of the digestive organs. Thus, in the Monopisthocotylea the intestine is lined by a continuous and unpigmented gastrodermis ; but in the Polyopisthocotylea the gastrodermis is typically discontinuous and consists of colum- nar cells, containing varying amounts of brownish or black pigment, interspersed with areas devoid of cells and consisting only of thin basement membrane (Baer and Euzet, 1961). In a number of species the pigment has been identified as hematin, a degradation product of hemoglobin (Llewellyn, 1954; Jennings, 1959). These differences in gastrodermal structure within the Monogenea are pre- sumably related to the differences in diet and they may reflect, also, further differ- ences in the site and course of the digestive process. In the present investigation, therefore, the relationships between diet, gut structure and digestion in the Mo- nogenea have been studied, as part of a comparative survey of nutrition within this class of Trematoda. MATERIALS AND METHODS The following species of Monogenea, listed systematically with details of their hosts and parasitic locations, have been examined : MONOPISTHOCOTYLEA Callcot\le kroyeri Diesing. Cloaca of the thorn-back skate, Raid clavata and the starry ray, Raid radiata. Entobdclla hippoglossi Miiller. Skin and general body surface of the halibut, Hippoglossus hippoglossus. Udonclla calit/oniin Johnston. Egg sacs of copepods (Caligus sp. ) found on the head and in the buccal cavity of the cod, Gadns callarias. 1 Present address : Department of Zoology, The Queen's University, Belfast, N. Ireland. 257 D. W. IIAI.TMX \M) J. B. JENNINGS POLYOPISTHOCOTYLEA Polystoma intcgcrriiiiiuii Fruhlich. Urinary bladder of the common frog, Rana ft inporaria. /liplozoon parado.nts Nordinann. Gills of the minnow, Pho.viiuis pho.vinus. Discocolvlc sat/ittdtit i.enckart. Gills of the trout, Sahno trutta. Diclidophora ;//<T/</;/<// Kiihn. Gills of the whiting, Gadus nicrlant/ns. Octodactylus [\tlinaia Leuckart. Gills of the ling, Molva niolra. ricctanocot\le (/iinnin/i Beneden & Hesse. Gills of the grey gurnard, Trigla gurnardus. To determine the food of each species, and to study the structure of the gut, .specimens were fixed in Bouin, Susa, or I0 c /c formalin immediately after removal from the host, and serial sections cut at 5 /JL after impregnation and embedding in polyester wax (m.pt. 37 C.) or paraffin wax (m.pt. 56 C.). For identification of intestinal contents sections were examined by one or other of the following methods : 1. The alcian blue method for mucins (Steedman, 1950). 2. The periodic acid-Schiff (P.A.S.) method for mucins and carbohydrates. 3. The mercuric bromphenol blue method for proteins (Mazia. Brewer and Alfert, 1953i. 4. The benzidine method for hemoglobin (Pickworth, 1934). 5. The application of various solubility and bleaching tests for hematin (sum- marized by Jennings, 1959). 6. The Gmelin test for hematoidin and bile pigments. 7. The Turnbull's and Prussian blue methods for ferrous and ferric salts. 8. Various routine histological methods, e.g., hematoxylin and eosin, Mallory's trichrome stain, Feulgen's reaction for nuclei, etc. To aid identification of the chosen food the host organs were fixed and examined by the above methods, for comparison of tissue components with the trematode's intestinal contents. Further, where the trematodes had obviously only recently fed, they were induced to regurgitate the food, by gentle pressure, and the material so obtained examined either fresh or after treatment as a fixed and stained smear. In the study of the feeding mechanisms the trematodes were observed alive upon their hosts, \\henever this was possible, and others were fixed and sectioned in situ. The latter process was facilitated by fixation in warm (40 C.) Bouin, or by plung- ing the host organ and attached flat worms into isopentane, cooled to - - 160 C. in liquid nitrogen, followed by transfer of the frozen mass into fixative held at - 1 C. The site and course of digestion were investigated by isolating recently fed trema- todes in aerated salt or fresh water ( Hedon-Fleig saline with added glucose for r<>lysf<nini ) and fixing individuals at progressive intervals up to three days, the maximum survival time for most .species. The progressive breakdown and absorp- tion of the tood was followed in sections prepared and treated as above. Enzyme activity in the alimentary system was investigated histochemically, using frozen or 45 C. paraffin wax sections prepared after fixation at - 1 C. in 10% formalin buffered to pi I 7.0. The histocheniical methods employed included the indoxyl acetate- method for non-specific eMerases (Holt, 195S), both metal-salt and azo-dye method- |".,r alkaline and arid phosplialases ( ( ioniori. 1 ( >52; Bnrsloiie, 1958). the NUTRITION OF MONOGENEA 259 Tween 80 method for lipase (Gomori, 1952) and the L-leucyl-/3-naphthylamide method for leucine aminopeptidase (Burstone and Folk, 1956). OBSERVATIONS MONOPISTHOCOTYLEA 1. Calicotyle kroyeri Calicotylc kroyeri feeds exclusively on epidermal cells and mucoid secretions derived from the lining of the skate cloaca. In many instances the gut lumen of specimens fixed immediately after removal from the host contained mucus, staining strongly with alcian blue and P.A.S., together with numerous large cells 10-12 p. in diameter and containing prominent nuclei (Fig. 1). These cells are identical with the epidermal cells in situ on the cloacal wall or lying free in the mucoid material coating the walls of the cloacal chamber. The mouth in C. kroyeri is anterior and ventral, and surrounded by a poorly defined oral sucker. The anterior lip of the sucker contains unicellular glands whose secretions are used for adhesion to the cloacal wall, and the posterior portion bears a tongue-like valve which on contraction cuts ofT the cavity of the sucker from the rest of the alimentary system (Fig. 2). The pharynx is highly muscular and de- void of gland cells, and is used to suck in the semifluid mucus and desquamated epidermal cells which are always present in the cloaca. The cloacal wall and its epidermis are always intact and undamaged, even when many specimens of Calico- tyle are present, and it appears that the pharynx never removes living epidermal cells or breaches the epidermis. The pharynx leads via a short esophagus into the intestine, which consists of two simple unbranched ceca. The esophagus is surrounded by many acidophllic gland cells (Fig. 2) which open into its lumen, but the function of their secretion remains unknown. The intestinal ceca are lined by a single-layered continuous gastrodermis, made up of columnar cells 16-18 /A tall and 6-8 //, wide, with granular cytoplasm and basal vesicular nuclei (Fig. 1). The cells go through a secretory cycle in which a small vacuole appears basally and then increases in size as it moves to the distal portion of the cytoplasm. The vacuoles eventually pass out into the gut lumen where they may remain as visible and discrete structures for varying periods before they finally disappear. The entire gastrodermis consistently shows a strongly positive reaction for non- specific esterases, apart from the vacuoles whose finely granular contents remain unstained (Fig. 3). The mucoid and cellular elements of the food are progressively homogenized as they lie in the gut lumen, demonstrating the occurrence of extracellular digestion. The enzymes responsible for this originate, presumably, in the esophageal glands and from the vacuoles released by the gastrodermis. No inclusions were seen in the gastrodermal cells, apart from the vacuoles, but the intense esterase activity seen in the cytoplasm suggests the occurrence of some intracellular digestion following absorption of partially digested material from the gut lumen. Non-specific esterases are found also in the cuticle, notably that of the anterior ventral region and that lining the oral sucker, and may be used by the trematode 260 D. W. HA1 T< IN AND .1. B. JENNINGS g.c. * FlGi RE. 1. (.'alicufylc hri'iyct-i. 'l'ran^\-ci->c ->^riimi of an intestinal arum .shoxvin.L; tlie uolated continuous sja-Orodrrnii- and, in tin- Innicn, rn-cntly in.^c^tcd lins) cpidi-rinal cells. Il<.-inato\ylin, rosin and alcian blur. Scale: 1 cm. 20 /,. NUTRITION' OF MONOGENEA 261 in some form of extracorporeal digestion to accelerate the sloughing-off of spent cells from the cloacal epidermis. 2. Entobdclla hippoglossi Examination of the intestinal contents of E. hippoglossi fixed immediately after removal from the host showed that in this species, as in Calicotylc, the food consists entirely of host epidermis and mucus, and no traces were found of ingested dermal tissue components such as chromatophores or blood cells. The ventral subterminal mouth leads directly into the pharynx, which is consid- erably modified from the usual trematode type to form a muscular-glandular feed- ing organ (Fig. 5). The anterior portion of this organ is entirely muscular, with flexible lips, and can be protruded through the mouth for application to the host epidermis. The posterior portion is glandular and consists of 40-50 large acido- philic gland cells, separated from each other by muscle fibers. Each cell communi- cates individually with the lumen of the anterior part of the feeding organ by a fine duct, and each duct opens distally at the apex of a large papilla (Fig. 4). The gland cells give no reaction with the indoxyl acetate method for non-specific esterases, but fresh frozen sections applied to thin films of solidified 2/o aqueous gelatine cause liquefaction and cavitation in the area covered by the glandular por- tion of the feeding organ, indicating the presence of a proteolytic enzyme. The feeding organ of E. soleae is reported to produce a similar gelatine-splitting protease (Kearn, 1963), and it seems likely, therefore, that protease production in the pharynx is characteristic of the entobdellid trematodes as a group. It was not possible to observe E. hippoglossi in the act of feeding, but the pres- ence on the host skin of circular lesions of the approximate diameter of the feeding organ indicates that the proteolytic secretions are used to erode and dissolve epi- dermal tissue prior to ingestion. This is supported by the fact that relatively feu- intact epidermal cells are found in the intestinal contents, even when the gut is full and the trematode obviously only recently fed. Generally the gut contents are quite homogeneous, acidophilic and stain only lightly with alcian blue or P.A.S., in marked contrast to the situation seen in Calicotylc. The feeding organ leads posteriorly into the intestine via a short esophagus, into which open the ducts of numerous unicellular glands lying in the parenchyma of the anterior portion of the body. These esophageal gland cells are intensely basophilic but the function of their secretion could not be detected. FIGURE 2. Calicotylc kroycri. Longitudinal section through the anterior region, o. g., oesophageal glands; p., pharynx; v, tongue-like valve which can close off the pharynx from the oral sucker. Mallory. Scale 1 cm. = 200 /j.. FIGURE 3. Calicotyle krdyeri. Horizontal longitudinal section of the anterior region, showing the pharynx (p.) and portions of the two intestinal ceca. The gastrodermis in each cecum shows intense non-specific estcrase activity. Holt indoxyl acetate method. Scale : 1 cm. = SOn. FIGURE 4. Entobdclla hippoglossi. Transverse section through the posterior glandular region of the feeding organ, showing the gland cells (g. c.) and papillae. Mallory. Scale: 1 cm. = 75 /j.. FIGURE 5. Entobdclla hippoglossi. Longitudinal section through the anterior region show- ing the muscular-glandular feeding organ, g. r., glandular region ; m. r., muscular region. Hematoxylin and eosin. Scale : 1 cm. = 125 /JL. 262 1). \v. 1 1 ALTON AND .1 IJ. JKNNINtiS The intestine is divided into two ceca which re-unite posteriorly by means of a commissure and give off over their entire length branched diverticula. It is lined throughout by a continuous gastrodermis consisting of uniform flattened cells, 12-15 p long and 5-7 p. tall, with finely granular cytoplasm and basal vesicular nuclei. Gland cells are absent and no enzyme activity could be demonstrated. The only variation obsenable in the gastrodermis is in the height of the constituent cells, and this is related to the amount of food present in the lumen, the cells becoming even more flattened as the intestinal walls stretch to accommodate newly ingested material. The amount of material in the gut lumen decreases with time, after feeding, but without noticeable change in consistency from the relatively homogeneous con- dition in \\hich the food is ingested. This fact, together with the absence of gland cells from the gastrodermis, suggests that the bulk of digestion in E. hippoglossi is effected by the secretions poured on to the food from the glands of the feeding organ before and during ingestion, aided perhaps by the secretions of the esophageal glands. The gastrodermis would thus appear to be entirely absorptive in function and to play little or no part in the production of the digestive juices. 3. Udonclla caligontin Udonclla caligontin lives attached to the egg sacs of copepods (C aligns sp.) which in turn are ectoparasitic in the buccal cavity and on the head region of cod, halibut and ling. The only recognizable material found amongst the gut contents of Udonclla was a mucoid substance staining lightly with alcian blue and P.A.S., and often the intestine contained only a finely granular acidophilic digest. Nothing can be seen to suggest that Udonclla feeds on the copepod tissues or body fluids, and it is con- cluded that the trematode ingests mucus, and perhaps sloughed-off epidermal cells, from the fish skin or mucous membrane adjacent to the copepod's point of attachment. The mouth in Udonclla is anterior and ventral, and leads directly into the large muscular pharynx. This can be protruded slightly through the mouth but is not armed or equipped with glandular elements so that it is unlikely that it penetrates host tissues. Feeding, therefore, is probably a case of merely sucking in the mate- rial lying on the fish epidermis. The intestine in Udonella, in contrast to that in most other Monopisthocotylea, is undivided and extend^ almost to the posterior end of the body as a simple sac, reminiscent of the sac-like gut of many rhabdocoel Turbellaria. It is lined by a flattened and continuous gastrodermis similar to that found in Entobdclla. Digestion appears to be entirely intraluminar, judging from the appearance of the gut contents, and nothing was seen to indicate intracellular digestion, as the gastrodermis shows no trace of esterase activity. POLYOPISTHOCOTYIJ .A 1. Polvsloina integerrimum Polystonia integerrimum is sanguinivorous, feeding on blood drawn from the capillaries of the frog urinary bladder, and no host tissues other than blood were found in the gut content s. NUTRITION OF MONOGENEA 263 The ventral mouth is encircled by an oral sphincter and leads into the cavity of the oral sucker. This is lined by cuticle and surrounded by numerous unicellular glands which open via long branched ducts over the external surface of the sucker and also into the oral cavity. The glands produce a granular proteinaceous secre- tion which stains strongly with the Mallory and Mazia methods, but gives no re- action for esterases or phosphatases. The distribution of the ducts conveying the secretion to the exterior indicates that it is probably used in adhesion. The oral cavity is linked with the large muscular and bulbous pharynx by means of a short cuticle-lined buccal tube, into w r hich the anterior portion of the pharynx projects. The wall of the pharynx contains, in addition to muscular elements, a number of large cells w r ith prominent nuclei and nucleoli, and a series of small vacuoles of unknown function ranged along the inner and outer surfaces at regular intervals (Fig. 6). The pharynx leads via the esophagus into a bifid intestine whose ceca run the length of the body and give off branches which in turn repeatedly subdivide and anastomose. The esophagus is a short muscular tube surrounded by numerous unicellular glands arranged in t\vo distinct zones. The cells of the inner zone, immediately around the esophagus, are smaller and produce a granular secretion giving an intensely positive reaction for alkaline phosphatase, while the outer larger cells produce a more coarsely granular and strongly acidophilic secretion quite free of phosphatases (Fig. 7). Fresh frozen sections and aqueous extracts of the esophageal region rapidly cause cavitation in gelatine films, indicating the production of a proteolytic enzyme by these esophageal glands, but it was impossible to determine which type of gland cell was responsible. Both types of gland cell discharge through long unbranched ducts which enter the pharynx at its posterior end and run forward between the cuticular lining and the underlying musculature to open finally into the anterior end of the pharynx lumen (Figs. 6 and 7). During feeding the oral sucker is flattened and flared against the bladder wall, and contraction of radial muscles within the sucker draws up a plug of bladder tissue whose tip reaches the anterior end of the pharynx. The plug is held secure by the constricting grip of the oral sphincter around its base while the sucking action of the pharynx, aided no doubt by proteolytic secretions from the esophageal glands, ruptures capillaries and draws blood into the intestine. Bladder tissue is never ingested, however, and very little damage is caused to the bladder epithelium. The structure of the gastrodermis in Polystoina has been described elsewhere (Jennings, 1959). In brief, the gastrodermis is a single-layered discontinuous structure made up of columnar cells 16-18 /A tall and 8-10 ^ wide, with basal vesicular nuclei and cytoplasm containing varying amounts of the pigment hematin, interspersed with areas devoid of cells and w r here only a thin basement membrane separates the gut lumen from underlying body tissues (Fig. 8). The hematin is contained within spherical vesicles up to 8 ^ in diameter and the number of these increases with age, so that a mature cell is loaded with pigment and the nucleus obscured. When this condition is reached the vesicles are extruded into the gut lumen or, more commonly, the entire cell disintegrates either in situ or after being shed from the gastrodermis. The vesicles themselves persist intact for some time, but eventually rupture to discharge their contained hematin. New, younger cells 264 D. \Y. HALTON VND J. B. JKXXIXGS w Pi. ' \ ) I CGI ! 6 Polystoma inteyerrimum. [.oii^itudiiial Motion of tin. 1 anterior region, y. c., cell- posiciior to the ])liar\u\ whose duels run forward between llie inner eutionlar lining and musculature of the pharynx and open in its anterior portion; L, intestine, lined by a dis- NUTRITION OF MONOGENKA 265 grow up to replace the spent cells and fill in the gaps in the gastrodermis, and thus the latter structure is in a state of constant degeneration and renewal. Digestion in Polystoma occurs by a combination of extracellular and intra- cellular processes. Erythrocytes entering the intestine are immediately hemolyzed and within three hours of ingestion their nuclei have also disintegrated. The freed nuclear material mixes with the other gut contents and causes the whole mass to stain lightly with Feulgen, but this reaction eventually disappears as digestion progresses. The intraluminar phase of digestion is accompanied by absorption of semi- digested substances by the smaller younger cells of the gastrodermis, and their cytoplasm becomes swollen with spherical aggregations of material showing the same staining reactions as that remaining in the gut lumen. These cells show in- tense alkaline phosphatase activity along their distal margins and this is obviously concerned with the process of absorption. The enzyme is best visualized by the azo-dye method since the black cobalt-sulphide end product of the calcium-salt technique may be masked by any hematin present. Absorption from the gut lumen continues until no stainable material remains. This situation is reached 2448 hours after a meal, depending upon the amount of blood ingested. Digestion is completed intracellularly in the vesicles within which material is aggregated as it is absorbed from the lumen, but of the enzymes con- cerned in the process, only non-specific esterases could be demonstrated histo- chemically. These are localized within the vesicles and cannot be demonstrated in the cytoplasm of the gastrodermal cells. As intracellular digestion proceeds, stainable material disappears from the vesi- cles and is replaced by granules of hematin resulting from degradation of the hemo- globin content of the meal. The hematin remains within the cell and thus the amount seen in a mature cell about to be shed from the gastrodermis probably repre- sents an accumulation from the digestion of several meals. Extrusion of hematin vesicles or the shedding of intact spent cells occurs 2448 hours after a meal and consequently there is at this time a marked increase in the amount of hematin lying free in the gut lumen. Many of the freed vesicles, prior to rupturing, still show traces of esterase activity and this confirms a suggestion made in an earlier account (Jennings, 1959) that enzymes concerned primarily with intracellular digestion may remain in the hematin vesicles and be eventually trans- ported to the gut lumen where they are released when the vesicles rupture. Due to the ramifications of the gut in Polystoma there is never complete evacuation be- tween meals, and it is likely that these enzymes of intracellular origin will still be continuous pigmented gastrodermis and containing hematin granules mixed with heavily staining hemolyzed erythrocytes ; o. s., oral sucker containing material regurgitated from the intestine ; vi., vitellaria. Mallory. Scale : 1 cm. = 75 /*. FIGURE 7. Polystoma integcrrimum. Longitudinal section of the anterior region, showing intense alkaline phosphatase activity in the inner zone of gland cells associated with the pharynx. Abbreviations as in Figure 6. Gomori azo-dye method. Scale : 1 cm. = 75 /j.. FIGURE 8. Polystoma integerrimum. Transverse section through the gastrodermis, show- ing the discontinuous structure and the intracellular aggregations of hematin. Mallory. Scale : 1 cm. = 20 /i. FIGURE 9. Diplosoon paradoxum. Longitudinal section of an individual fixed in situ on the host gill. g. f., gill filament ; pi., plug of gill tissue drawn up and held by the buccal sucker. P.A.S. Scale: 1 cm. = 250 M. 266 D. \Y. MAI |M\ AND .1. H. JENNINGS present in the lumen when the next meal is taken, and thus contribute to the intra- luminar digestive phase. No specific source of the intraluminar digestive enzymes was located, other than the lu matin vesicles, and it seems likely, therefore, that the proteolytic secretions of the esophageal glands will play .in important part in extracellular digestion, entering the intestine with the fond and initiating hemolysis and nuclear breakdown. The principal endprodnci of hemoglobin digestion in Polystoma is hematin but a small proportion of the hemoglobin is converted to hematoidin, an iron-free, acid- soluble crystalline substance closely related to the bile pigments. Hematoidin crys- tals are only rarely found in histological preparations of Polystoma, however, due to their solubility in the .standard fixatives, but can be seen in fresh squash prepara- tions of the gastrodermis in about 10% of the cells. 2. Diplosoon pt Diplozoon /'tirado.vum feeds predominantly on blood, but small amounts of gill tissue, epithelial cells and mucus are also found amongst the gut contents. The adult Diplozoon consists of two individuals united in permanent copulation, with organic fusion of their bodies midway along the long axis, so that the com- posite individual is X-shaped. Each individual retains a terminal ventral mouth opening into a buccal cavity which bears laterally a pair of buccal suckers. An oval, muscular pharynx, devoid of glandular elements, protrudes slightly into the buccal cavity and leads backwards into the intestine. This extends posteriorly in each individual as a single much-branched cecum, and where the bodies of the two indi- viduals fuse, the two ceca unite by a median canal, so that the two intestines are confluent. ni[>!o.::oon lives attached to the gills of the host minnow by the clamps of the two opisthaptors and during feeding one or both of the anterior ends attaches itself to a gill filament by means of the buccal suckers. The grip is aided by adhesive secre- tions produced by clusters of gland cells around the buccal cavity which open on to the anterior body surface. The buccal suckers draw up a plug of gill tissue (Fig. 9), in much the same manner as the oral sucker in Polystoma draws up a plug of bladder tissue. The plug extends through the buccal cavity to the pharynx, which is protruded slightly and applied to the tip. Prolonged suction bursts the super- ficial blood capillaries, and blood, together with a small amount of gill tissue, enters the intestine. There is no evidence indicating the use of histolytic secretions to effect rupture of the gill capillaries, and no serious damage is caused to the gill fila- ments by the feeding activities of the trematode. The gastrodermis resembles that of Polystoma in that it- is a discontinuous and decidtu us structure whose individual cells contain the characteristic hematin-laden vesicles. The cells are interspersed with areas of basement membrane either devoid of cells or covered by thin, extremely flattened and unpigmented young cells. The course of digestion follows closely that observed in Polysloma, hemolysis of the er\ throcytes occurring during or very soon after ingestion and being followed by partial intraluminar digestion. Soluble substances are absorbed by the gastro- deimis and digestion sul>~<-i piently completed intracellularly. with the production of hematin as a \isible insoluble endproducl. As in I'olys/o'ini the cells actively absorbing materials from the gut lumen show intense alkaline phosphatase activity NUTRITION OF MONOGENEA 267 distally and this decreases as the cell ages and reduces its digestive functions. No esterase reaction could be demonstrated in the gastrodermis, but the entire nervous system shows intense cholinesterase activity and this provides a simple but effective means of demonstrating the system in toto (Halton and Jennings, 1964). The vitelline glands of the reproductive system are in intimate contact with the intestine for most of its length and show at all times positive reactions for alkaline phosphatase, lipase and aminopeptidase, indicating metabolic activity possibly con- cerned with absorption and utilization of food materials from the gastrodermis. In a few instances the intestine of newly fed Diplozoon contained, in addition to the hemolyzed blood, a number of reddish needle-shaped crystals 1 50-200 /j, in length. These were water-soluble but could be fixed in absolute ethyl or methyl alcohol, when they stained strongly with the benzidine technique for hemoglobin. The crystals gradually disappeared in the living animal as digestion progressed, and they probably resulted from crystallization of hemoglobin released from hemolyzed erythrocytes and concentrated by absorption of water from the gut con- tents during the early stages of digestion. 3. Discocotyle sagittata Discocotyle sagittata appears to feed exclusively on blood drawn from the super- ficial capillaries of the trout gills. The mouth is anterior and ventral, and opens into a buccal cavity possessing laterally a pair of very large bilobed buccal suckers. The buccal cavity opens posteriorly into a small muscular non-glandular pharynx. It was not possible to observe Discocotyle in the act of feeding, but judging from the similarities in structure and habit it is likely that the breaching of the host capil- laries and the ingestion of blood are effected in the same manner as in Diplozooii. The buccal suckers are larger and more powerful than in the latter species, how- ever, while the pharynx is relatively smaller, so that the suckers probably play a greater part in creating the necessary suction. No evidence of the production or use of proteolytic secretions could be found, and no significant amount of damage is caused to the gill filaments by the feeding activities of the trematode. Neither gill tissues nor mucus were observed in the gut contents of the speci- mens examined. The pharynx opens directly into the bifid intestine whose ceca extend to the posterior end of the body and give off numerous lateral branches which in turn sub- divide and ramify between the vitellaria and other organs. The gastrodermis resembles that of Polystoma and Diplozoon, and is made up of large hematin-laden cells, 18-20 ^ long and 4-6 ^ tall, which are interspersed with smaller, flattened non-pigmented cells and areas completely devoid of cellular elements. The appearance of the gastrodermis indicated that digestion in Discocotvle fol- lows much the same course as in Polystoma and Diplozoon, and this was con- firmed from histological examination of individuals fixed at progressive intervals after removal from the host. Hemolysis and intraluminar digestion are accom- panied by active absorption of the products by the gastrodermis, with subsequent completion of digestion and production of hematin within intracellular vesicles. Absorption is particularly noticeable in the smaller non-pigmented cells, and both these and the larger cells show intense distal alkaline phosphatase activity. -<>> s D. W. HALT ND J. B. JENNINGS Mematin is eliminate'! from thi gastrodermis by extrusion of the vesicles or by ilie sloughing oil" of intact spent < It was not possible to de nonstrate ibe presence <if proteolytic enzymes in the gastrodermis, bv histocliei: nethods, but as in Diplozoon the vitellaria give strong positive reactions for lipase and aminopeptidase. 4. Diclidophora Diclidophora incrlautji lecds chieflv upon blood but small amounts of gill tissue and mucus are also ingested. The mouth is ventral and subterminal, and opens into a typical buccal cavity with lateral paired buccal suckers. The pharynx is spherical, muscular and devoid of glandular elements, and feeding is effected by suction of the host tissue. A long esophagus links the pharynx with the bifid intestine whose ceca give off lateral much-branched diverticula. The latter are enveloped by the numerous \itellaria of the reproductive system. The gastrodermis in Diclidophora, as in the other Polyopisthocotylea already de- scribed. is a discontinuous and deciduous structure whose cells contain varying amounts of hematin and show the characteristic distal zone of alkaline phosphatase activity. The cells are much smaller than in the other genera investigated, how- ever, and even when fully mature and loaded with hematin are only 6-8 ft long and 3-4 p tall. Digestion in Diclidophora is effected by a combination of extra- and intra- cellular processes and follows much the same course as in Polystoma, except that hematin appears to be the sole endproduct of hemoglobin degradation and no traces of hematoidin were found. A small amount of non-specific esterase activity can usually be demonstrated in the gut contents of specimens fixed soon after feed- ing, but this does not increase in amount with time and appears, in fact, to be de- rived from the gill tissue ingested along with mucus as the subsidiary component of the diet. In control sections of whiting gill approximately 10% of the epi- thelial cells showed non-specific esterase activity and it is likely that the activity seen in the Diclidophora gut contents originates in these cells. The gastrodermal cells show no enzyme activity, other than alkaline phosphatase, that could be detected by the techniques used, but the vitellaria, as in the other genera studied, give positive reactions for lipase and aminopeptidase. 5. Octodactylus paluiala Ocioditctylns palmata feeds predominantly on blood drawn from the host gill .ipillaries but as in Diclidophora and Diplozoon, this diet is supplemented by gill tissue and mucus. terminal mouth opens into a buccal cavity which possesses a pair of large lateral buccal suckers, dill tissue is drawn up through the mouth, and suction by the bulbous and highly muscular pharynx ruptures the capillaries and draws blood into th line. The pharynx is devoid of gland cells and its action in procuring the ears to be entirely mechanical. Tin gul , of recently fed Octodactylus generally include mucus and gill lie in somewhat larger quantities than are found in Diclidophora and Diplosoon, but no appreciable damage to the gill filaments of the host was observed. NUTRITION OF MONOGENEA 26 The intestine is of the- usual polyopisthocotylean type, being In' lid with the coca of considerable length and giving off many branched lateral diverticula. The gastrodermis differs somewhat from that of the other genera examined in that only relatively few areas are completely devoid of cells at any one time, and these are usually restricted to the walls of the two main ceca. The cells are small, as in Diclidophora, and range from 3-8 /L in height and 6-8 /i in width. The great majority of the cells contain hematin but the pigment granules are generally all confined within a single large vesicle, 3-6 /JL in diameter, rather than distributed amongst four or five smaller vesicles as, for example, in Polystoina. The larger- sized vesicles often fill the entire cell and displace the nucleus to one side away from its normal basal position. In fixed preparations the vesicles appear as solid masses of hematin, but in fresh squashes the individual pigment granules are free and exhibit constant Brownian movement within the confines of the vesicle. Digestion in Octodactylus follows the pattern observed in the other polyopis- thocotyleans studied. Hemolysis is completed very soon after ingestion and then intraluminar digestion is accompanied by absorption and the completion of digestion intracellularly. The gastrodermal cells show a distal zone of high alkaline phos- phatase activity which is particularly intensified during absorption. The hematin resulting from intracellular degradation of hemoglobin accumulates within the vesicles until eventually the distal margins of the individual cells break down and the hematin is discharged into the gut lumen. During this process, and while the cell is recovering, the cell becomes crescent- or cup-shaped and the dis- organized distal margin shows only diffuse alkaline phosphatase activity. Cells in this condition may continue to absorb material from the lumen, however, and often show a single small secondary hematin vesicle basally. This increases in size as the cell recovers from expulsion of the primary vesicle and moves distally, almost fills the cell, and is eventually expelled. The gut contents in Octodactylus often show non-specific esterase activity but, as in Diclidophora, there is every indication that this originates in the gill tissue and not in the gastrodermis. No other enzymatic activity could be demonstrated histochemically in the intestine, but again lipase and aminopeptidase were abundant in the vitellaria. 6. Plcctanocotylc guniardi None of the specimens of Plcctanocotylc gnrnardi available for examination was recently fed, but since the gastrodermal cells contain at all times large amounts of hematin it is concluded that blood forms the dominant, if not the sole, component of the diet. No traces of gill tissue or mucus were found, but this could con- ceivably be due to the progress of digestion since the previous meal. The alimentary system resembles that of Diclidophora or Diplozoou, with paired buccal suckers, a muscular pharynx and a bifid, much-branched intestine. The gastrodermis is of the typical discontinuous and deciduous type, with somewhat sickle-shaped pigmented cells interspersed with naked areas devoid of cells. DISCUSSION These observations on the nutrition of a number of monogenetic trematodes con- firm indications available from previous accounts that there is a fundamental differ- ence between the Monopisthocotylea and Polyopisthocotylea as regards the domi- 270 I). \v. HAI.TOX AND J. I 1 .. JENNINGS nant components of the diet. The three monopisthocotyleans studied, from quite different parasitic locations, all feed on the host's epidermis and epidermal secre- tions, and similar feeding habits have been described in Entobdclla squcnnata (Heath, 1902), Mcgalocotylc nntrc/iiiata (Folda, 1928), Lcptocotylc minor and Acanthocotyle sp. (Llewellyn. l ( '54i, Entohdclla solcac, Capsala inartinicri, Tro- chopus sp. and slcantliocotylc sp. ( Kearn, 1963). Thus, this type of diet would appear to be a characteristic feature of the Monopisthocotylea. Uspenskaya i 1 () 62), however, .states that in four other species (Dactylogyrus Testator, D. so- licliis, Anchylodiscoides pcinisilitri and Tetraonchus inoncntcron) varying amounts of blood are found in the intestinal contents, together with gill tissue and mucus, but the latter substance's predominate. In the Polyopisthocotylea, in marked contrast, blood forms the major, and some- times the only, component of the diet. Of the species examined in the present study, Polystount integerrimum and possibly Discocotylc sagittata feed entirely upon the host's blood, while Diplozoon paradoxum, Diclidophora mcrlangi and Octo- dactyltts palmata supplement the blood diet with varying quantities of gill tissue and mucus. Ingestion of blood, or the presence of an intestinal pigment which is presumably hematin and hence indicative of a blood diet, has also been reported in Hc.\'acol\lc sp., Onchocotyle sp., Octocotyle sp. and Microcotyle sp. (Goto, 1895) ; Axine spp., and Diclidophora spp. (Goto, 1895; Llewellyn, 1954) ; the larval and neotenic adult stages, as well as the normal adult stage, of Polystoma integerrimum (Gallien, 1934; Llewellyn, 1954); Kuhnia scombri (Sproston, 1945; Llewellyn. 1954); Hc.vabotJi riitm appendiculata and Anthocotyle mciiitcci (Llewellyn, 1954) and Pricca c \bhtni and Protomicrocotyle caran.r (L^spenskaya, 1962). It is reasonable to suppose that the earliest Monogenea lived ectocommensally upon fish in much the same sort of way as modern Tennocephalida live on crus- tacean and other hosts. The fish epidermis and its mucoid secretions would form a readily available and rapidly replenished source of food to the flatworm, once the association was established, and by utilizing this the primitive Monogenea would become truly ectoparasitic. On this view the modern monopisthocotylean Mo- nogenea, living as a rule upon the external surface of the host, retain ancestral feed- ing habits and the only modification found is the evolution in groups such as the entobdellid species of a specific feeding mechanism involving the use of histolytic "salivary" secretions. Even species such as Calicotylc which have sought the shel- ter of the host's cloaca, and are apparently on the way to becoming endoparasitic, still use the original type of food. The polyopisthocotylean Monogenea, on the other hand, are predominantly gill parasites, having migrated into the branchial chamber of their piscine hosts, and they have departed considerably from the supposedly primitive feeding habits. The highly vasculari/ed gill I'da.ments offer an extremely nutritious and, again, readily available food in the form of blood, and the basic monogenean feeding mechanism of a suctorial pharynx is capable of obtaining this food without any modification other than slight elaboration of the oral and buccal sucker system. Thus, the dif- ferences in diet between the Monopisthocotylea and Polyopisthocotylea have not affected the feeding mechanism, and the anterior region of the alimentary system remains remarkably constant in structure throughout the Monogenea and, indeed. the l)i^enea. This unitormitv contrast- sharply with the situation in the Turbel- NUTRITION OF MONOGENEA 271 laria, where considerable diversification in the form of the pharynx is linked with the utilization of a wide variety of prey, ranging from Protozoa and many other invertebrates to tunicates (Jennings, 1957). The differences in diet within the Monogenea do, however, have considerable effect upon the cellular structure of the gastrodermis. In the Monopisthocotylea digestion of the food creates no particular problem as regards the elimination of unwanted endproducts, even though the process is completed intracellularly. In the Polyopisthocotylea, however, the diet of blood and the retention of the intra- cellular digestive phase result in the intracellular production of hematin. The elimination of this insoluble substance is achieved at the expense of the continuity of the intestinal lining, and produces the discontinuous or deciduous gastrodermis characteristic of the sub-order. This involves wastage of cellular materials and thus the Polyopisthocotylea appear to be incompletely adapted to a blood diet. A more complete adaptation would be the extracellular formation of hematin, or the degra- dation of hemoglobin along some other pathway which allows the unwanted iron to be eliminated in a soluble form. The Trematoda are in fact capable of evolving such digestive processes, and these are seen in certain sanguinivorous Digenea such as Hacmatolocchus and Haplomctra (Halton, unpublished work). A compensating factor arising from the disintegration of gastrodermal cells in the Polyopisthocotylea is that intracellular enzymes are released to mingle with the gut contents and initiate breakdown of the next meal. Unfortunately it has proved impossible to localize the source of other digestive enzymes in either the Mono- pisthocotylea or the Polyopisthocotylea with the techniques at present available. It seems likely that the secretions of esophageal glands, poured on to the food during ingestion, play an important part in the extracellular phase of digestion, but this cannot be conclusively demonstrated. Certainly, however, the gastrodermis in the Monogenea has not evolved to the point of specialization of cellular function, for it shows no signs whatsoever of differentiation into glandular and absorptive or phagocytic components. In this respect it differs radically from the gastrodermis of other members of the phylum Platyhelminthes, such as the triclad Turbellaria, and of other acoelomates, such as the Rhynchocoela, where well differentiated gland cells occur and where there is separation of secretory and absorptive or phagocytic functions (Jennings, 1962a; 1962b). SUMMARY 1. A comparative study has been made of the food, feeding mechanism, gut structure and digestive processes in representatives of the two sub-orders of the Trematoda Monogenea. 2. The two sub-orders differ fundamentally as regards the dominant compo- nents of the diet, the Monopisthocotylea feeding on the epidermis and associated mucoid secretions of the host while the Polyopisthocotylea feed primarily upon the host's blood. In some instances the Polyopisthocotylea supplement the diet with small amounts of host tissue and mucus. 3. The feeding mechanism in both groups consists basically of a muscular pharynx, and ingestion is the result of muscular suction, aided in some cases by histolytic secretions produced in pharyngeal or esophageal glands and used to erode the host tissues. D. \Y. HALT* 'X . l> J- I'. JENNINGS 4. The two sub-orders differ considerably with regard to the structure of the gasirodennis, that of the MonOj being a continuous cellular structure as in mosl other animals while in the Polyopisthocotylea it is a discontinuous and decidu- ous structure \\hose cells cont; varying amounts of the pigment hematin. 5. Digestion in hoth the Monopisthocotylea and Polyopisthocotylea is effected by a combination of extra- and intracellular processes, but in the Polyopisthocotylea intracellular degradation of hemoglobin results in the accumulation within the Castro- dermal cells of insoluble hematin, and the elimination of this substance results in the deciduous gastrodermi> characteristic of the sub-order. LITERATURE CITED I'.AI-K. J. (',., AND L. Ei ,\ i. 1961. Traite de Zoologie. Anatomie-Systematique Biologic. Tome IV. Edit. Pierre- 1'. < .rasse, Masson et Cie, Paris; 944 pp. DONE, M. S.. 1 n 58. I listochemical demonstration of acid phosphatase with naphtho] AS-phosph /. Nat. Cancer InsL, 21: 523-53''. BURSTOXK. M. S.. A \D J. E. FOLK, 1956. Histochemical demonstration of aminopeptidase. /. 1 1 isloclieui. Cylocheiii., 4: 217-226. FOLDA, F., 1'L'S. Mei/a!i>f,>t\'le iiiiin/inata, a new genus of ectoparasitic trematodes from tin- Rock Fish. Publ. Puget Sound Mar. (Biol) Slat., 6: 195-206. GALLIE.X. I... 1 ( '34. Rcchcrchcs experimentales sur le (limori)liisme evolntif ct la biologie de J'ulysloiiia iiileiierriiiiiiiu Frohl. Tra-r. Sta. Zool. iriinercit.v. 12: 1-182. GOMORI, (i.. 1 ( >52. Microscopic Histochemistry. Univ. of Chicago Press, Chicago. GOTO,- S., 18 n 5. Studies on the ectoparasitic tremafodcs of Japan. /. Coll. Sci. Tokyo. 8: 1-273. HALTON, D. \Y., AND J. B. JENXIXC.S, 1964. Demonstration of the nervous system in the mono- genetic trematode Diplozoon ^iinidu.riiiii Nordmann by the indoxyl acetate method for esterases. Nature, 202: 510-511. HEATH, H., 1902. The anatomy of Efibdclhi sqiiauuila sp. nov. Proc. Calif. .Ian!. Sci. (Zool.}, 3: 109-136. MOLT, S. J., 1958. Studies in enzyme histochemistry. Proc. Ro\. Soc. London, Scr. 11, 148: 465-532. 1 1 S.MXGS, J. B., 1956. A technique for the detection of Polystunnt intci/crriiiuiin in the common frog (Rana temporaria) . J. Helminth., 30: 119-120. IKXM.XGS, J. B., 1957. Studies on feeding, digestion and food storage in free-living flatworm^ (Platylu-Iinintlu-s: Turlx-llaria). Biol. Bull. 112: 63-80. II.VXIXGS, (. I!.. 1 () 5'^. Studies on digestion in the moiiogenetic trematode folysto/ua integer- rimum. J. Helminth., 33: 197-204. IEXXIXGS, J. B., l%2a. A histochemical study of digestion and digestive enzymes in the rhyn- chocoelan Linens ruber (O. F. Miillcr). Biol. Bull., 122: 63-72. IKXXIXT.S, |. H., I ( >o2l>. Inirther studies on feeding and digestion in triclad Tnrbellaria. Biol. Bull, 123: 571 581. KKAKX, G. C., 1963. Feeding in some mcmogenean skin parasites: lintobdclht sol cue on Solea solca and Acunlli, sp. on R'aia chn'nlti. J. Mar. Biol. .Issue., 43: 749-76''. LI.KXVKU.VX, J., 1954. Observations mi the food and gut pigment of the Polyopisthocotylea (Trematoda : \\\ I, J'tinisitolot/y, 44 : 428-437. Af.\/iA, D., P. A. |'>KI-\\IK \\n M. \MII;I, 1953. The eytochemical staining and measurements of protein with mercuric hrompheiiol hlue. Biul. Bull., 104: 57-67. Pic K\\ OKTII, F. A., l'J34. A iirv, method of study of the brain capillaries and its application to the regional localisation of mental disorder. ./. ./;;/., 69: 62-71. OSTIIX, X. (i., 1 ( '45. 'I 11- Kuhnia n.g. (Trematoda: Monogenea). An examination of thr value of some specific characters, including factors of relative growth. Pi si/olof/y. 36: 1/6 1 STEEDMAN, H. F., 1 ( '5(). A.lcian Blue sii.S. A ne\\ stain for mucin. Ounrt. J. Mier. Sei., 91: 477-47". ' 5KAYA, A. \ ., I ( 'n2. pitanii mouogei ut icheskikh sosal'schikov (Nutrition of the nogenoidea). D nauk. S.SS.R., 142: 5-12. DIGESTIVE ENZYMES OF THE CRYSTALLINE STYLE OF STROMBUS GIGAS LINNE. 1 I. CELLULASE AND SOME OTHER CARBOHYDRASES SHIRO HORIUCHI 2 AND CHARLES E. LANE Institute of Marine Science, Unircrsity of Miami, Miami, Florida 33149 The crystalline style is a flexible hyaline rod composed of mucoprotein gel. Among marine molluscs it occurs in most lamellibranchs and in a few gastropods. The digestive enzymes of the crystalline style are set free into the gut lumen by dissolution of the style as it is rotated against a cuticular gastric shield by the cilia of the style sac epithelium. Yonge (1932) pointed out that Strombus gigas, feeding on fine filamentous algae, was the largest of herbivorous gastropods. Yonge's observations were later confirmed by Robertson (1961) and by Randall (1964), who showed that this conch feeds unselectively on delicate macroscopic algae, on unicellular algae, and on algal detritus. Microscopic examination of the stomach contents of Strom bus gigas Linne from the Miami area has confirmed the ability of this animal to digest cell walls of filamentous green algae and to dissolve algal cytoplasm. These changes were particularly marked in green algae adherent to the surface of the head of the crystalline style. A cellulase enzyme system would facilitate use of algal cellulose by 6". gigas. Cellulolytic activity has been demonstrated in the crystalline style of the clams, Mya and Mactra (Lavine, 1946), an oyster, street and a mussel, Mytilits (Newell, 1953), an African bivalve, Caclatnni and a marine snail, Melanoidcs (Fish, 1955), the wood-boring pelecypods, Bankia (Nair, 1955, 1957) and Teredo (Greenfield and Lane, 1953), and the lamellibranchs, Cardhtm and Sc orbicular ia (Stone and Morton, 1958). During feeding experiments Dean (1958) observed that algal cells of Cryptomonas were destroyed while this alga was swimming near the style of an oyster, Crassostrea. In this paper the cellulase activity of the crystalline style of S. gigas will be described. Subsequent papers in this series will examine other enzymes of the crystalline style. MATERIALS AND METHODS Specimens of the queen conch, S. gigas, which is native to Southeast Florida and the West Indies, were collected from shallow water adjacent to Virginia Key, Miami, Florida. They were maintained in sea water pens on the laboratory grounds until they were used. The style of S. gigas is large ; one of the largest in the present series of samples measured 18.5 cm. long, 0.55 cm. wide, and weighed 1 Contribution No. 630 from The Marine Laboratory, Institute of Marine Science, Uni- versity of Miami. 2 Postdoctoral Fellow of The Heart Institute of The National Institutes of Health under Grant No. HE-5489. Present Address : Biological Laboratory, Sophia University, Tokyo, Japan. 273 SHIRO HORIUCHI AND CHARLES E. LANE 2.100 gin. The average moisture content was 82.4% and N averaged 8.19% by a micro-Kjeldahl method. Broken algal fragments and other detritus are ofte i em- bedded in the substance of the portion of the style (ca. 0.5 cm. in length) protruding from the style sac into the lumen of the gut. The animals were separated from the shell and the style removed quickly. The exposed head of the stvle was cut off and discarded. The surface of the re- mainder of the style was scraped with a sharp knife to remove adherent debris. It was then washed by shaking several times in sterile sea water. The styles were then homogenized in a sterile \Yaring Blendor with sterile 0.66 M phosphate buffer ipll n.55 i made isotonic with sea water by the addition of NaCl. This medium was O.h20 .17 XaCl, the same as that used earlier for the extraction of cellulase in Teredo ( ( Ireenlield and Lane, 1953). The viscous homogenate was stored at 4 C. for 12 hours, then centrifugal at 20,200 g at 4 C. for 30 minutes. The small residue was discarded. The supernatant solution was lyophilized, and the result- ing powder was stored at - 10 C. There was no significant loss of cellulolytic activity during three months of storage. The powder was dissolved in citric acid- sodium phosphate buffer at room temperature and centrifuged briefly at low speed. The supernatant solution was filtered through a Millipore membrane. The sterility of the resulting enzyme solution was established by broth culture with Difco Tryptic Soy Broth. Cultures were negative for growth at both 24 and 48 hours at 30 C. Control experiments employed the sterile enzyme solution that had been boiled for 10 minutes. Cellulolytic activity was estimated both by the formation of reducing sugar and \iscosimetrically. Reducing sugar was estimated by the methods of Somogyi (1928, 1952) as modified by Nelson (1944). Optical density was measured at 500 m/u. with either the Beckman Model DU spectrophotometer or Coleman Model 6A spectrophotometer. Samples of sodium carboxymethyl cellulose (CMC) from Her- cules Powder Company, of different degrees of polymerization (D.P.) were used as substrates in the cellulase assay. Purified sodium alginate (Fisher Scientific Company), and carrageenan (Marine Colloids, Inc.) were also employed. In test- ing for cellobiase. glucose was estimated by the Glucostat Special reagent (Worth- ington Biochemical Cor]).). The pH of the reaction mixture was determined with a Beckman glass electrode before and after incubation. Digestive activity was ex- pressed as //g of reducing sugar liberated per milligram of dry style extract per hour. Changes in substrate viscosity were measured in Ostwald viscosimeters. Three ml. of substrate solution (CMC to final concentration O.S' < } were mixed in the viscosimeter with 3.0 ml. of Mcllvaine's citric acid-sodium phosphate buffer (pH 6.75). After thermal equilibrium in the 35 C. water bath had been achieved, the time required to empty the capillary was noted. One-tenth ml. of enzyme solution was added and mixed in a stream of air bubbles. The time required to empty the capillary was measured at intervals from the time of mixing. RESULTS Filtration through Millipore membranes does not affect the activity of style en- zyme solutions as judged by two different criteria (Tables 1 and II I. The yields of reducing -oigar from CMC 70 of three different degrees of polymerization in- ENZYMES OF THE CRYSTALLINE STYLE 275 TABLE I Hydrolytic activity of crystalline style extract before and after bacterial filtration* Substrate Unfiltered enzyme solution Mi Hi pore-filtered enzyme solution Boiled enzyme solution CMC 70 M 90.5 9.0 89.7 10.3 11.7 1.7 Phosphoric acid-swollen cellulose 10.3 0.7 10.9 1.1 3.8 0.4 Cellulose powder Sodium alginate Carrageenan Cellobicse 2.1 0.3 5.7 0.3 2.4 0.7 8.9 0.5 1.9 0.3 6.1 0.5 2.7 0.5 8.7 0.5 0.7 0.2 0.6 0.3 0.7 0.2 3.7 0.4 * Activity expressed as ^tg. reducing sugar/mg. crystalline style powder /hour. Each value is the mean and standard deviation of 10-17 determinations. Ki'uctants incubated at 35-37 C. at pH 6.75. cubated with crystalline style enzyme solutions are shown in Table III. This table shows that different degrees of substitution in the CMC substrate had only a slight effect on the activity of the enzyme preparation. These results differ somewhat from those reported for Liinnoria by Ray (1959). In this form maximum cellulase activity was found when CMC 70 High was the substrate. When the cellulase ac- tivity of 6". gigas style extract was estimated viscosimetrically, however, the results, shown in Figure 1, more nearly resemble those reported by Ray. Whatman No. 1 filter paper, swollen in 85 % phosphoric acid and suspended at 0.5% concentration in phosphate buffer and the same concentration of Whatman cellulose powder, was also used as a substrate. These results also appear in Table I. The style enzyme solution is less effective on these substrates than on the CMC samples used. Figure 2 shows the linear relationship between cellulase activity and enzyme concentration measured by protein nitrogen. The relationship between pH and cellulolytic activity is shown in Figure 3. There is a single peak of activity between pH 6.8 and pH 7.2. When determined viscosimetrically after 60 minutes incubation the pH opti- mum was 6.75. The pH of gut contents of 6". gigas ranged from 6.25 to 6.65. TABLE II Viscosity of enzyme-substrate* before and alter bacterial filtration Substrate Incubation time 15 min. 30 min. 60 min. 90 min. 120 min. f I 67.8 1.4 54.7 1.2 44.9 2.0 39.6 2.2 36.5 2.4 CMC 70 M 1 II 74.2 3.1 62.9 3.2 52.1 3.3 47.4 2.7 44.5 1.8 Sodium alginate ] I 89.0 3.2 I II 88.1 2.2 80.9 2.8 82.2 3.8 67.7 2.1 72.0 3.2 58.2 2.9 63.9 db 3.2 52.3 2.8 56.7 2.7 / I 90.9 1.9 83.3 2.5 74.7 2.2 68.4 1.8 64.3 2.2 Carrageenan \II 90.7 5.8 86.9 0.1 79.8 0.6 74.2 0.4 70.7 0.1 * Yisccsity is expressed as time in seconds for capillary emptying. I = Unf Itered enzyme solution. IT = Millipore-filtered enzyme solution. 276 SIIIKi ) IIORIUCH] AND i HARLES E. LANE TAHI.I. 111 activity oj the < rystalh ^trombus i;/i;.v wiili unions substrates Substrate D.S. Viscosity fig. glucose/mg. of enzyme In. CMC To low 30 cps. 31.4 CMC 70 mol. d.77 7o cps. 41.1 CMC 70 hiiili 0.72 2100 cps. 15.0 CMC" )() hi.Ji 0.94 280 cps. 17.8 CMC 120 h 1 .-55 cps. 7.8 Suollen filter paper ( Yllulo-r powder . 0.7 Incubation at so and pi I 7. -1 lor CMC, pH 7.3 for other substrates. The optimum temperature and the temperature of inactivation of the enzyme solution were determined. The relationship between the incubation temperature and cellulase activity showing an optimum about 40 C. is presented in Figure 4. Thermal stability of the enzyme solution was determined by assaying residual ac- tivity after heating the enzyme solution to various temperatures for fifteen minutes CO o o CO CO <I LU cr o LU O CONTROL CMC 70 LOW CMC 70 MEDIUM CMC 70 HIGH 10 20 30 40 50 INCUBATION TIME (MINUTES) I-'K,I ]<]. 1. Ki'tVrt of crystalline style enzyme on CMC 70 of different viso^ity. Final concentration of CMC /o was 0.8 ; pi I was n.75 and tcinprratuiv S3 C.
ENZYMES OF THE CRYSTALLINE STYLK
277
ct
QK _L_
0.05 0. 10
ENZYME CONCENTRATION (Mg N)
FIGURE 2. Cellulase activity of crystalline style extract at various enzyme concentrations.
Reaction mixtures containing 12 ing. CMC 70 of medium viscosity were incubated at 30 C,
pH 6.8 for two hours.
ml
100 -
CO
o
o
CO
cc
<t
50
CO
o
LU
CC
8
pH
FICUUK 3. Cellulase activity of the crystalline style at various pi 1 levels. Suhstrate was
CMC 70 of medium viscosity ; temperature was 30 C. ; time was two hours.
278
SHIRO IIORIUCHI AM) CHARLES E. LANE
(Fig. 5). Activity was unditnini-Ucl up to 45 C. Between 45 C. and 50 C..
cellukilytic activity was markedly reduced and was 90% destroyed at 70 C.
Cellobiase activity (Table EV) was estimated by incubating cellobiose with
crystalline style en/.yme solul llucose produced was determined by the spe-
cific glucose oxidase method \Yorthington Biochemical Corp.). As compared
with the cellulase activity, the cellobiase acthity is slight. Since the crystalline
style of -V. gigas appears i deficient in cellobiase, it appears that digestion of
cellulose by this animal does not necessarily include cellobiose as an intermediate
(Levinson and Reese. 1"50).
200
LU
CO
8
CO
a:
%
CO
o
o
100
20 30 40
TEMPERATURE C
50
FIGURE 4. Effect of temperature on cellulolytic activity of the crystalline style extract.
Substrate was CMC 70 medium; pH 6.75; incubation time was two hours.
The relationship between decreasing viscosity and increasing concentrations of
reducing sugar during cellulolysis is presented in Figure 6.
DISCUSSION
There is general reluctance to attribute cellulase enzyme activity to higher
ia because symbiotic microorganisms are i ivolved in cellulose breakdown in
r animals. Indeed, Morton (1952. 1960), Newell (1953) and Barring-
ton i have emphasi/ed the occurrence of spirochaetes in the crystalline style
of many bivalves. Some, at least, of the cn/ymatic capability of the style is attrib-
uted to these symbionts.
ENZYMES OF THE CRYSTALLINE STYLE
279
CE
LU
Q_
UJ
CT
50
CO
j_
30
40 50 60
TEMPERATURE C
70
FIGURE 5. Temperature stability of cellulase in the crystalline style. Activity of the
heated enzyme, assayed after two hours in a reaction mixture containing CMC 70 medium, at
.15 C., pH 6.8.
Levinson and Reese (1950) suggested that at least two kinds of enzymes were
involved in the complete degradation of native cellulose. First, a C l enzyme causes
a rapid decrease in viscosity by converting native cellulose to linear anhydroglucose
chains. These are then hydrolyzed to the soluble sugars glucose and cellobiose by
C x enzymes (Gascoigne and Gascoigne, 1960; Levinson and Reese, 1950). Our
results strongly suggest that the cellulolytic capability of the crystalline style of 6".
gigas, together with certain other amylolytic activities, are of molluscan rather than
bacterial origin. If it be assumed that CMC in solution is a straight-chain mole-
cule made up of 1 ,4-/3-glucose linkages (Levinson and Reese, 1950), then all the
TABLE IV
Cellobiase activity of the crystalline style of Strombus gigas Linne
pH
5.7
6.6
7.6
Glucose
16.3
16.2
10.3
0.5 % cellobiose in Mcllvaine buffer was incubated at 35 C. for three hours. Reaction
mixtures contained 1.8 mg. of lyophilized style.
280
SHIRO IIOR1UCHI AND CHARLES E. LANE
soluble derivatives of cellulose u>ed in ilii> study were hydrolyzed by a C x enzyme of
the crystalline style. 1 )igestion of algal cellulose by .V. (jif/as probably includes some
preliminary microbiological degradation followed by extracellular digestion by style
i'ii/yines in the .stomach (Evans ;ind Jones, 1962). Digestion of lower molecular
weight sugars and other partially digested foods is probably completed intracellu-
larly in phngocytic cell- of the digestive diverticula.
CO
o
CO
>
^ 50 -
CO
<t
o
UJ
Q
30 60 90
INCUBATION TIME (MINUTES)
120
IMI.CKK 6. Tin- relationship between decrease in viscosity and formation of reducing sugar
during cellulolysis by the crystalline style. Reaction mixture contained O.b'/f CMC 70 medium
viscosity; ]>H 6.75 at 35 C.
Si'.M M AKY
The crystalline style was extracted in buffered saline and the extract subse-
quently lyophilixed. The activity of the resulting enzyme powder was determined
by measuring the amount of reducing sugar it liberated from various substrates under
different conditions, and by measuring the decrease in viscosity of these substrates.
Cellulase activity was proportional to enzyme concentration. The pH optimum was
between pi I 6.8 and pi I 7.2. ( tptimum temperature for enzyme activity was 40 C.
P.etween 45 and 50 C'., cellulolytic activity was markedly reduced. C'ellobiasc
activity of the style extract was slight. Bacteria-free extracts were as active as
unsterile preparations. Some implications of these observations arc discussed.
LITERATURE CITED
KINGTON', K. J. \V., l ( 'f)2. Di{ic-ii\-c nes. hi: Advanci-s in Comparative Physiology
rmd Biochemistry. O. Lo\\vnstein, Editor. Ac;id<'inic 1'ros, N. Y., Vol. 1, pp. 1-65.
|)i. \x. I)., 15<S. Xe\v property crystalline Mylr of Cruxxoxtrca riri/iiiica. Science,
128: S3".
ENZYMES OF THE CRYSTALLINE STYLE 281
EVANS, W. A. L., AND E. G. JONES, 1962. Carbohydrases in the alimentary tract of the slug,
Arion ater L. Coinp. IHuchan. Physiol., 5 : 149-160.
FISH. G. R., 1955. Digestion and the production of sulphuric acid by Mollusca. Nature, 175:
733-734.
GASCOIGNE, J. A., AND M. M. GASCOIGNE, 1960. Biological Degradation of Cellulose. Butter-
worths, London.
GREENFIELD, L. J., AND C. E. LANE, 1953. Cellulose digestion in Teredo. J. Biol. Chan., 204:
669-672.
LAVINE, T. F., 1946. A study of the enzymatic and other properties of the crystalline style of
clams : evidence for the presence of a cellulase. /. Cell. Camp. Physiol., 28 : 183-195.
LEVINSON, H. S., AND E. T. REESE, 1950. Enzymatic hydrolysis of soluble cellulose derivatives
as measured by changes in viscosity. /. Gen. Physiol., 33: 601-628.
MORTON, J. E., 1952. The role of the crystalline style. Proc. Malacol. Soc. London, 29 : 85-92.
MORTON, J. E., 1960. The function of the gut in ciliary feeders. Biol. Rev., 35 : 92-140.
XAIR, N. D., 1955. Cellulose activity of the crystalline style of the wood-boring pelecypod
Bankia indica Nair. Current Sci., 24 : 201.
NAIR, N. B., 1957. Physiology of digestion in Bankia indica; the enzymatic activity of the
crystalline style. /. Sci. Industr. Res., 16C : 39-41.
NELSON, N., 1944. A photometric adaptation of the Somogyi method for the determination of
glucose. /. Biol. Chem., 153 : 375-380.
NEWELL, B. S., 1953. Cellulolytic activity in the lamellibranch crystalline style. /. Mar. Biol.
Assoc., 32: 491-495.
RANDALL, J. E., 1964. Contributions to the biology of the queen conch, Strombus gigas. Bull.
Mar. Sci. Gulf Carib., 14: 246-294.
RAY, D. L., 1959. Some properties of cellulase from Limnoria. In: Marine Boring and Foul-
ing Organisms. D. L. Ray, Editor. University of Washington Press, Seattle, pp.
372-386.
ROBERTSON, R., 1961. The feeding of Strombus gigas and related herbivorous marine gastro-
pods. Nohilac Naturae, 343 : 1-9.
SOMOGYI, M., 1928. The distribution of sugar in normal human blood. /. Biol. Chem., 78 :
117-127.
SOMOGYI, M., 1952. Notes on sugar determination. /. Biol. Chcni., 195: 19-23.
STONE, B. A., AND J. E. MORTON, 1958. The distribution of cellulases and related enzymes in
Mollusca. Proc. Malacol. Soc. London, 33: 127-141.
YONGE, C. M., 1932. On the size attained by the crystalline style in Tridacna and Strombus.
Proc. Malacol. Soc. London, 20: 44-45.
T11K HEMOCYTE!, OF RHODNIUS I'ROLIXUS Sl'AL.
COLVARD JONKS
I >cp(irtnii'iit at Eni ly, University of Maryland, College Park, Maryland
Wigglesworth ( l l '. : ' . -Mtied four kinds of hemocytes in Rhodnlns nymphs,
and in ] ( )55 he identifu additional types. His interest centered on the most
abundant hemocyte, which will he referred to in the present paper as the plasnuito-
eyte. Jle ( 195(>a, pa.^e 142) stated that plasmatocytes ". . . show definite signs
of secretory activity just at the time when hormone of the thoracic gland is being
produced," and he ( 1^5(>b, page 97) concluded that one of the distinct functions of
the plasmatocytes is that ". . . in the early stages of moulting they seem to play
some essential part in the production of the moulting hormone by the thoracic
glands." Wigglesworth (1956b) demonstrated that the plasmatocytes possess
mucopolysaccharide inclusions and mentioned that this material was liberated during
the later stages of moulting. The signs of secretory activity which Wigglesworth
stated occur in the plasmatocytes of fourth stage nymphs were an average in-
crease in cell sixe and the sudden appearance of many, clear, non-staining vacuoles
in the cytoplasm between the third and fourth day after these insects took a blood
meal.
The initial purpose of these studies was to examine quantitatively these two cri-
teria for secretory activity in the circulating plasmatocytes of Rlwdniits in fresh.
unfixed, unstained coverslipped samples of hemolymph with dark phase contrast
microscopy. As these studies were being made, it became evident from the form
and behavior of the different types of hemocytes that a change in the terminology
of the different cells was needed.
Hemocytes were examined daily throughout the fourth and fifth stages and in
adults at 970 to 1400 X. The hemocytes were also studied using supravital meth-
ods and in fixed and stained smears. Hemolymph was obtained from a severed leg
or antenna.
RESULTS
1. General observations
The hemolymph of Rhodnius is a clear, pale, straw-yellow, watery fluid. When
examined in a hanging-drop preparation or in a moist chamber the hemolymph
does not obviously coagulate or gel in 24 hours, although a very finely granular
precipitate may form on long standing as the drop partially darkens. In a very
f<-\v cases, a rare plasmal veil may be observed. In a moist chamber, the hemo-
lymph slowly darkens and finally appears either pale brown or has an irregular scat-
tering of dark sooty patches, but the drop never becomes generally dark- brown or
uniformly black in vitro. None of the hemocytes darken or blacken.
2. Phase contrast observations and classification
the classification and terminology suggested by Jones (1962), the various
type- ocytes of l\'liodniiis can be readily identified in fresh, undiluted, un-
fixed, unstained hemolymph with a dark phase contrast microscope.
282
HEMOCYTES OF RHODMUS 283
a. Prohemocytes
The prohemocytes are always small, mostly round to ovoid cells, generally with
a relatively large, single, centrally-located, round nucleus (Plate I, Figs. 1 and 2).
Usually the nucleus has extremely fine, dark grey, granular chromatin material
around a single, slightly excentric round nucleolus. Prohemocytes have a relatively
small amount of smooth, dark grey, homogeneous, or sometimes finely granular cyto-
plasm. In some cases, the nucleus may be excentric and ovoid, with a single slight
indentation; the nucleolus may he irregular in shape, or, in a few cases, absent.
Prohemocytes can be seen with a few, relatively large, dark grey, round inclusions.
On a number of occasions, prohemocytes have been seen to degenerate in vitro : the
small, round, cartwheel-like nucleus is generally ejected, and the cytoplasm rounds
up into a pale-grey sphere with fine dancing particles within and around it (Plate I,
Fig. 3 ). On many occasions, a prohemocyte has been seen to undergo unmistakable
and intense ameboid movements /;/ vitro, when none of the other hemocytes made
comparable movements. During such ameboid movements, the nucleus was fre-
quently constricted or otherwise distorted. In older nymphs, the prohemocytes
measured from 5 to 7 microns in diameter. Mitotic divisions were seen only in
cells slightly larger than the typical prohemocyte. At metaphase, the chromosomes
were so tightly packed that they appeared as a single dark-grey bar. The meta-
phase plate was contained in a clear, hyaline central zone within the cell. Vacuoles
and granules were usually conspicuous in dividing cells. Prophases could not be
accurately identified in the preparations examined.
b. Plasmatocytes
Plasmatocytes are exceedingly variable in form (Plate I, Figs. 5, 6, 9, 10-15).
The most common variety is an ovoid cell with a single, large, centrally-located,
round-to-ovoid nucleus containing a single, round-to-ovoid nucleolus. The cyto-
plasm contains sharply-outlined round, ovoid, or short rod-shaped, or tear-drop-
shaped granular inclusions (Plate I. Figs. 5, 6, 14, 15). With dark phase micros-
copy, the edges of these inclusions are generally sharp black and the enclosed
granular space bright.
In unfixed plasmatocytes, the cytoplasm often contains few (t\vo) to many
(about 32) round or irregular, clear, non-refringent, watery, colorless vacuoles of
various sizes (Plate I, Figs. 11-13). Some plasmatocytes can be seen with large,
less sharply-defined, round or spherical, grey inclusions, often having a very pale
greenish cast.
Plasmatocytes tend to send out several to many, fine, thread-like pseudopodia
(Plate I, Figs. 5, 11-13). In some cases, exceedingly thin cytoplasm will spread
out from the cells and terminate in extremely delicate spikes. Round, spindle, and
irregular forms of plasmatocytes abound in the hemolymph. Small, medium and
large varieties of each of the above may be found in a single preparation.
Although the plasmatocytes have a distinct tendency to spread out and form pe-
ripheral thread-like pseudopodia in thin wet films, they were very rarely observed
to perform vigorous ameboid movements comparable to those seen in some pro-
hemocytes. Although the plasmatocytes are probably capable of ameboid activity
in vivo, such movements do not critically distinguish plasmatocytes from other types
of hemocytes.
JM
.1 UK O iLVARD [ONES
O O
I
V*.
V-
'.
(>
IV
g
17
X
"I
16
12.
.
..' . V-
'
F
'>. i
*t * r Sj
20
Zl
' '*
14
**.
zz
2.3 25 a
2.5
Z7
[i 28
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C .
PLATE I
I'lra^t appearance <>l Rhodnius hemocytes.
l*"i(;ri<i'> 1 AMI 2. 'J'ypieal prolienioeyti's.
FIGURE 3. Lysed proheiih- Tlie nucleus is at the ri.ulil and the Cytoplasmic envelope
;ind uraiinK^ at the left.
FlGURK 4. Small spiml!< ytoid with excentric nucleus and without inclusions.
FlGt'KK 5. Non-vacuolated iila^nialueyte with thread-like p^endi ipodia.
HEMOCYTES OF RHODNIUS
The sizes of plasmatocytes throughout the fourth stadium of Rlwdniiis were
noted but were so highly variable in both unfixed and methanol-fixed films within
and between individuals that no difference in average sizes could be detected at any
time during the stage with the methods used. Since many more hemocytes are
available in the fifth stadium, plasmatocytes were measured every day between the
first through ninth, eleventh through sixteenth, and on the twentieth days after
nymphal feeding. Plasmatocytes in unfed fifth stage nymphs and in unfed adult-
were also measured. In all, 335 plasmatocytes were measured. The minimum
values for individual widths varied from 4.4 to 8.8 microns and the maximum values
from 8.8 to 17.6. The minimum values for individual lengths ranged from 7.7 to
11 and the maximum values from 12.1 to 66 microns. The mean widths of the
plasmatocytes during the fifth stadium varied from 7.7 to 12.2 and the lengths from
9.9 to 20.6 microns. The overall mean dimensions of the plasmatocytes for the
period examined were 9.8 (standard error 0.3 ) by 14.5 (standard error 0.6) microns.
There was a distinct tendency for the plasmatocytes to decrease in length during
the fifth stadium while the widths did not change greatly. Measurements were
made on a series of coded slides, but the writer was unable to accurately distinguish
between plasmatocyte sizes at any time during the fifth stadium.
Although Wigglesworth (1955 ) stated that the average size of the plasmatocytes
increased between the third and fourth days after fourth stage nymphs feed, meas-
urements made on the cells shown in his Figure 5 A and B show statistically insig-
nificant differences in mean width, length, circumference and area (Table I). The
same applies to the plasmatocytes illustrated in his Figure 6 (Table I). But what
is striking about Wigglesworth's Figures 5 and 6 is that the fixed adherent plas-
matocytes of fourth stage nvmphs are strikingly and significantly smaller than the
unfixed circulating forms ( Table I ) . Whether this is clue to fixation or to the
spreading-out of plasmatocytes in the fresh preparation is not clear. The fixed
FIGURE 6. Non-vacuolated plasmatocyte without pseudopodia.
FIGURES 7 AND 8. Round and ovoid oenocytoids with characteristically excentric nucleus
and with dark, smooth cytoplasm.
FIGURE 9. Small plasmatocyte without inclusions, vacuoles, or pseudopodia.
FIGURE 10. Small plasmatocyte with a few inclusions, vacuoles, and blunt pseudopodia.
FIGURES 11-13. Typical vacuolated plasmatocytes with obscured nucleus and large watery
vacuoles and discrete inclusions.
FIGURES 14-15. Spindle plasmatocytes showing very fine granules (mitochondria?) and
larger inclusions (mucopolysaccharide?).
FIGURE 16. Spindle form of granular hemocyte.
FIGURES 17-19. Typical ovoid granular hemocytes.
FIGURE 20. Large granular hemocyte with one, short blunt extrusion at upper right.
FIGURE 21. Round granular hemocyte.
FIGURES 22-23. Partially lysing granular hemocytes.
FIGURE 23a. Very small intact granular hemocyte with obscured nucleus.
FIGURE 24. Lysing granular hemocyte, showing tin- hyaline cytoplasm and round cart-
wheel-like nucleus.
FIGURE 25. Fully lysed granular hemocyte.
FIGURE 26. Large oenocytoid with glassy rod-like inclusions.
FIGURE 27. Large oenocytoid with finely granular network and one vacuole.
FIGURES 28-29. Typical large oenocytoids with characteristic excentric nucleus and long
FIGURE 30. Adipohemocyte with excentric nucleus and various sizes of fat-like droplets.
286
JACK O ILVARD JONES
same as the unfixed circulating forms measured in the present study. It is con-
cluded from the present observations and from calculations on Wigglesworth's fig-
ures (Table I), that a change in the sizes of plasmatocytes is not a practical cri-
terion for their possible secretory activity because of an inherently large individual
variation.
In fresh wet films, various inclusions in many plasmatocytes were observed to
very rapidly turn into clear, colorless vacuoles. Unfixed circulating plasmatocytes
of 72 fourth stage Rlwdniits were classified as either with or entirely without vacu-
oles in differential counts of generally 100 hemocytes per insect per group of two
to five nymphs, two to five- days after ecdysis, and daily after the nymphs fed, for
a period of 12 days. Each insect was used only once. During the fourth stage the
mean percentages of plasmatocytes in fresh hemolymph varied from 22.7 to 61.5.
TABLK I
t.'til< illations made from plasmatocytes oj jourth .v/</r Rhudnins, us illustrated
hy Wigglesworttl (1V55), with standard errors
FisuM-
No.
iMf.iMMrnients
No.
( ,-ll.x
Days alter
nymphal
feeding
Mean width
U)
Mean length
(/O
Mean
circumference
(/.)
Mean area
<M-)
5A
1
2
4
3
12.40.6
11.60.4
29.62.9
27.82.8
9 1.8 14.9
98.817.9
156.819.8
157.826.6
SB
1
2
3
4
13.70.9
13.01.3
36.02.9
,U.42.5
127.020.0
132.714.2
186.2 36. 6
185.630.0
6A
1
2
7
3
8.30.3
8.2 0.2
16. 2 1.0
16.5 1.0
33.8 1.4
38.6 1.7
66.9 5.7
66. 7 5.7
6B
1
2
6
4
10.1 0.8
io.4o.9
16.0 1.1
16.11.1
26. 6 2.6
39.9 2.9
108.3 17.0
105'3 6.7
with an overall mean of 44.2. Of these. 83.8% to 96.8 '/ (mean of 92.3%, standard
error of 0.8) had few-to-many vacuoles in their cytoplasm. Even in unfed nymphs.
94.3% of the plasmatocytes encountered in differential hemocyte counts were vacu-
olated. A few extremely vacuolated plasmatocytes were seen in only four insects
during the fourth stadium. It i> evident from these findings that vacuolation of
circulating plasmatocytes cannot be a very useful criterion of changes in their pos-
sible secretory activity during the fourth stage. It is not clear why there should
be such a great discrepancy between the present findings and those of Wigglesworth
( ]''55 i. \Yiggle>worth'.s Figure 5 shows very few vacuoles on the third day and a
considerable (about 10-fold) increase- in vacuoles on the fourth day in circulating
plasmatocytes. Hi> Figure (> indicates that fixed adherent plasmatocytes have
many more vacuoles than the unfixed circulating forms on the fourth day.
Unfixed circulating plasmaiocytes of fifth stage h'liodniits were sub-divided
into those with no or very few vacuoles and those with few to many vacuoles in
differential counts of generaib 200 hcmocvtes per insect per group of four to li\e
nymphs. Thirty-nine insects were used for the first seven days after ecdysis. a
Separate group being examined each day. One hundred and one nymphs were
HEMOCYTES OF RHODNIl'S 287
used to stud}- changes following the blood meal, generally five insects being studied
daily from the day the nymphs took a blood meal to the twentieth day thereafter.
During the first seven days after ecdysis to the fifth stage, plasmatocytes in
differential hemocyte counts varied from 47.1 to 68.7. and 95.9% to 98.4% of them
were vacuolated. On the da\ the insects fed and during the next day, differential
counts of plasmatocytes averaged 44.7 r r to 53.8% , and of these 9(>. 1 ' , to 99.3% were
vacuolated forms. Between the first and second days after the nymphs took blood,
however, a spectacular shift in the presence of vacuolated plasmatocytes was re-
corded. From the second through the twentieth flay, circulating plasmatocytes
averaged 29.8% to 63.7% (overall mean of 51.5% ). Between the first and second
days after nymphal feeding, the percentage of plasmatocytes which were classified
as vacuolated forms dropped from 96% to 40%. and thereafter more or less steadily
declined to about 8% on the twentieth day ( i.e., before ecdysis to the adult stage).
\\ hen five newly-ecdysed fifth stage Rhodnius were submerged for one minute
in water at 55 C, it was observed that most (97.5% ) of the plasmatocytes still
vacuolated in ritro; but when nymphs which had taken a blood meal were similarlv
heat-fixed, very few of their plasmatocytes vacuolated in ritro. Fifth stage nymphs
were heat-fixed on seven representative days after the blood meal and hemocytes
from three to five insects for each day were examined. In differential counts, the
plasmatocytes were classified as those with few or no inclusions and those with
conspicuous round, ovoid or irregular, phase-dark inclusions. Plasmatocytes aver-
aged 32.7% to 49%, and 82.1% to 93.5% (mean of 89.6%) of them had inclusions.
Clearly the problem of vacuolation of plasmatocytes in Rhodnius needs further
study. But, if one assumes that the secretory activity of plasmatocytes is indeed
correlated with cytoplasmic vacuolation, as \Yigglesworth ( 1955 ) has indicated,
then the present data collected on unfixed hemolymph could be interpreted to mean
( 1 ) that the circulating plasmatocytes are highly secretory throughout the entire
fourth stadium, and during the fasting period after ecdysis to the fifth stage, and
(2) that there is a remarkable decrease in their secretory activity shortly after fifth
stage nymphs take a blood meal. Additional studies are clearly needed before such
interpretations can be accepted. The present data do not support the idea that
circulating plasmatocytes suddenly become secretory during the time when the
thoracic gland hormone is being produced in either the fourth or fifth stadia.
c. Granular hemocytes
The granular hemocytes of Rhodnius are typically larger and noticeably thicker
than plasmatocytes in thin films of hemolymph examined with phase microscopy
(Plate I, Figs. 16-20). However, very small granular hemocytes have been seen
in fresh hemolymph films (Plate I, Fig. 23a). Freshly withdrawn granular hemo-
cytes often have a very pale, yellowish-brown cast, are ovoid to spindle in shape,
and are characteristically filled with numerous, discrete, round, granular inclusions
of a mostly uniform size from 0.5 to 1 micron. The granules generally tend to
obscure the relatively small, round, centrally-located nucleus in fresh material.
With the ordinary bright field microscope, the granules in these unfixed cells appear
quite vague and could easily be overlooked or mistaken for fine droplets (vacuoles).
Of the numerous granular hemocytes examined in this study (approximated
50,000), only 20 were seen with one, short, blunt, or spike-like clear pseudopodium.
288 JACK COLYARD JONES
On a few occasions granulocytes have been seen to retract very rapidly their spindle
ends and round up. I'nlikc aocytes, some of the granular hemocytes have
been observed to rock hack and n>nh very slightly in situ. Unlike plasmatocytes,
they were never observed to send out pseudopodia in vitro.
In unfixed films of her .ymph, the granular hemocytes occur in two verv di>-
tinct forms: those which rmain intact for long periods in vitro (Plate I. Fig>.
16-20) and those which suddenly degenerate or lyse generally shortly after with-
drawal of the hemolymph sample (Plate I, Figs. 22-25). Many granular hemo-
cytes of various >i/< been watched as they degenerate /';/ vitro. The intact
cell seems to twist suddenlv. contract or constrict along its longitudinal axis ; and
the cell may then collapse like a balloon, releasing the round, cartwheel-like nucleus
and many fine dancing granules (Plate I. Figs. 21-23). Many times, as the cell
breaks down, the cytoplasmic envelope fragments into two or more spherical hyaline
masses with some enclosing dancing granules, as well as with granules around the
masses. The granules suddenly released from the disintegrating granulocyte are
much more sharply outlined than in the intact cell and may have a very faint green-
ish cast. The granules and cytoplasmic fragments do not quickly vanish but tend
to maintain their identity for a considerable time. The cytoplasmic fragments and
extruded nuclei greatly complicate both differential and total hemocyte counts.
The lysing or lysed granular hemocytes strikingly resemble cystocytes (but they
do not lead to coagulation or gelation of the plasma ).
Submersion of Rhodnius in a water bath at 55 C. for one minute generally did
not reduce the percentages of granulocytes lysing in vitro, but collection of fresh
hemolymph into 0.75% Versene largely prevented lysis of these cells. Collec-
tions of hemocytes in \% to 3% Versene severely damaged the hemocytes: the
surface of the cells appeared abnormally thickened.
Widths and lengths of granulocytes were measured in unfixed wet films of
hemolymph from fifth stage nymphs on eleven representative days after they took
a blood meal. Of the 130 granular hemocvtes measured, the minimal values for
individual widths ranged from 4.4 to <->.9 microns and the maximal values from 1 1
to 16.5; the minimal values for individual lengths ranged from l '. ( > to 13.2 microns
and the maximal values from 22 to 35.2. The mean dimensions of the granular
hemocytes were 10.3 (standard error 0.3) by IS. 8 (standard error 0.4) microns.
There \vas no marked change or trend in the length-width measurements of grannlo-
cytes during the fifth stage after feeding.
d. Oenocytoids
The cells which will be termed the Oenocytoids of Rhodnius occur in two dis-
tinct forms. In fresh hemolymph examined with phase microscopy, the first
variety is a relatively small, round, ovoid cell with one or two sharp spindle en<K
and the cytoplasm is very smooth, dark grey, and homogeneous. The nucleus is
sharply outlined, round and characteristically excentric (Plate I. Figs. 4. 7 and Si.
-erond, and most commonly encountered variety of oenocytoid is a very large
plasi vie-like cell, often occurring as hi/arre variations of the spindle form
I Plate I. ; 26-29). These large cells are characteri/ed bv having extremeb
line, long, phase-dark filaments at the spindle ends and b\ a large excentric nucleus,
often with two nucleoli. The inclusions are sometimes in the form of an irregular
HEMOCYTES OF RHODNIUS
finely granular network or appear as delicate, faintly outlined glassy rod:
have a very faint greenish cast (Plate I, Fig. 26). The large bizarre
often occur in clusters of two to four, and in some cases appear fused to each c
On some occasions, irregular nuclei and apparent hinucleate forms have been s<
Some of these cells have been seen to send out a few filamentous cytoplasmic
extensions.
On rare occasions, hemocytes with an excentric nucleus and many brilliant fat-
like droplets of various sizes have been encountered in the hemolymph (Plate I.
Fig. 30). These cells should be termed adipohemocytes only when they can be
clearly distinguished from fat body cells. At various times typical large fat body
cells can appear in the hemolymph (in some cases, at least, their appearance results
from accidental dislodgement at the time of sampling). Adipohemocyte-like cells
have been seen in fixed whole-mounts of thoracic glands. The scarcity and erratic
occurrence of the small adipohemocytes in the hemolymph make it most imprac-
tical to include these cells with other hemocytes in most differential counts. Since
and typical fat body cells may be found in Rhodiiiits, it is useful to place all circu-
lating cells containing fat droplets in a special category where they may be listed
separately.
f. Granulocytophagous cells
Unmistakable plasmatocytes have been seen engulfing a single intact granulootr
and/or the nucleus of the lysed form (Plate II, Figs. 31-34). In addition, very
large, plasmatocyte-like cells, measuring 20 to 35 microns or more in diameter, have
been observed with two to eight engulfed intact granular hemocytes or their nuclei
(Plate II, Figs. 35-39). These large phagocytes tend to send out characteristically
very extensive pseudopodia, which may extend 30 microns and more beyond the
main portion of the cell (Plate II, Fig. 39). While the very large forms may be
only a hypertrophied form of plasmatocyte, they are sufficiently distinctive in si/e
and activity to be listed separately in differential counts, and for convenience will
be termed granulocytophagous cells. Whether the large granulocytophagous cells
are, in fact, giant plasmatocytes is by no means certain.
3. Observations on supravital preparations
To further characterize the different types of hematocytes, fresh drops of un-
fixed hemolymph from fifth stage nymphs were collected on slides previously coated
with a thin, even, dry film of the following dyes: (a) neutral red, (b) phenol red,
(c) congo red, (d) eosin Y, and (e) Janus green H. Wet coverslip films were
examined with and without phase contrast.
Neutral red was picked up by the plasmatocytes and concentrated uithin yellow,
orange, or red cytoplasmic inclusions. The granular hemocytes and oenocytoids
did not encorporate neutral red. The nuclei and cytoplasmic fragments from the
lysing or already lysed granulocytes also did not stain. None of the hemocytes
encorporated phenol red or congo red. The nuclei of lysing and fully disintegrated
2 ( )() JACK i i >LVARD JONES
granular heniocues stained pale rose with eosin Y but the cytoplasm and granules
did not stain. Other types of hemocytes did not definitely eucorporate the eosin.
With Janus green B. the granules within intact granular hemocytes quickly became
a pale but distinct slate blue; those nuclei which were ejected from lysing granulo-
cytes did not stain. Many vacuolated plasmatocytes had a dull slate-blue cast to
them but the vacuoles did not stain. In some plasmatocytes brilliant sky-blue inclu-
sions were visible. Other hemocyte tvpes did not stain siipravitally with Janus
green B.
32.
31
^ *W
- * * ''(I) J
-. e.
Vl. -> . -* ,, ':
t ~*^af i
b^ ^ '
i -
34
^ .
. - v
*. * o , "
}
37
'
'
x *&
33 '.
PLATE II
FIGURES .U-^4. Plasmatocytes which lia\'e each (.n.ynlfccl a .sin.iilr granular hemocyte.
Fici'KKs 35- >V>. I-ar.yi- granulocytophagous cells which have ciigulU-d two or more yranulur
liemoryti-.- and/or their nuclei Note the very extensive pseudopodia in leisures 37-39.
4. Observations on ji.\-cd and stained smears
In thin and thick, air-dried smears of hemolvinph obtained from uulixed or heal-
lixed Rhodnius and subse(|uently treated with ethanol. methanol or Caruoy prior to
staining with Giemsa or Wright stain or with Harris hematoxylin and eosin, the
granular hemocytes generally could not be readily recognixed, and none of the hemo-
cytes appeared sharply acidophilic. In those granulocytes which were identifiable.
the round inclusions did not stain but appeared as sharply outlined circular bodies,
often \\ith a faint yellowish casl against a pale blue or faint grey cytoplasm.
When the hemolymph was fixed with alcoholic Bouin and stained with eosin
HEMOCYTES OF RHODNIUS
azur-II, those granulocytes which could be recognized had faintly pink-
cytoplasm with colorless granules. The prohemocytes were varying shades
blue with faint red-purple nuclei. The oenocytoids were basophilic around the
nucleus but the abrupt spindle ends of these cells were often distinctly eosinophilic
In some oenocytoids a fine purple-staining meshwork could be seen.
In general, regardless of the fixative employed, the different types of hemocyte:
did not stain sharply with vertebrate blood stains and were often very difficult to
distinguish. Even the best stained smears were notably inferior to the examina-
tion of fresh unstained cells with phase contrast microscopy.
It is important to note, however, that Wigglesworth (1955) observed that the
adherent granular hemocytes of Rhodnins were acidophilic after fixation with Car-
noy or Bouin and staining with either Alasson trichrome, hematoxylin and eosin, or
with Prenant's ferric trihematin. In osmium-ethyl gallate preparations, Wiggles-
worth (personal communication ) observed that the inclusions of the granular hemo-
cytes appeared as colorless spheres or vesicles. In ordinary stained preparations,
he found the granular hemocytes to be conspicuous for their lack of granularity.
DISCUSSION
The terms used here for three of the hemocytes of Rliudnius present no problem
relative to the terms used by Wigglesworth (1933, 1955) for the same cells; thus,
the prohemocytes are equivalent to his proleucocytes, plasmatocytes are the same as
his phagocytes or amebocytes, and the adipohemocytes are comparable to his adipo-
leucocytes or lipocytes. A complex problem arises, however, with the changes in
the names of two clear-cut types of hemocytes: (1 ) the cells which are here termed
the granular Iicinocytcs of Rhodnins are referred to by Wigglesworth as oenocytoids
and possibly also as large granular cells, and (2) the cells which are here termed
oenocytoids are referred to by Wigglesworth as large non-granular spindle cells
and as non-phagocytic giant hcuioc\tcs | Wigglesworth (personal communication)
considers these to be variant forms of the plasmatocyte] .
Wigglesworth (1933) considered the granular hemocytes to be comparable to
the oenocytoids of Poyarkoff (1910) because (1) when fixed, the cytoplasm ap-
peared homogeneous and stained with eosin, and (2) they were specifically phago-
cytized by certain other hemocytes. Nevertheless, the cells here termed granular
hemucytcs of Rhodniits differ strikingly from the oenocytoids of most other insects
in that (1) the nucleus in intact cells is centrally located whereas in most oeno-
cytoids the nucleus is characteristically excentric (Hollande. 1909, 1911 ; Poyarkoff,
1910; Bogojavlensky, 1932; Rooseboom, 1937; Yeager. 1945; Jones, 1962). (2)
The granular hemocyte of R/wdniits is never a binucleated cell whereas oenocytoids
may have two nuclei (Hollande, 1911 ; Bogojavlensky, 1932). (3) The cytoplasm
of the granular hemocyte is not dense or elaborately textured whereas in most oeno-
cytoids the cytoplasm is dense and contains canaliculi, threads or crystals (Bogo-
javlensky, 1932; Yeager, 1945; Nittono, 1960; Jones, 1962). (4) The granular
hemocytes of Rhodniits stain with eosin in certain preparations (Wigglesworth,
1933), whereas the oenocytoids of many other insects are generally amphophilic or
basophilic (Bogojavlensky, 1932; Yeager, 1945; Nittono, 1960; Jones, 1962),
and at best are faintly eosinophilic (Yeager, 1945). (5) The granular hemocytes
2 n 2 JACK CO! \ AtfD JONES
of A'liodiiins are often vcr\ numi i the hemolymph (they can make up 30 f ',', to
70% of the cells encountered in ; ; ', icnrial counts), whereas the oenocytoids have
not been reported to rise ev< 10% level (Yeager, 1945; Jones, 1950; Nit-
tono, 19(>() i. (6) Tlie gra-; ar lieuiocytes of Rhodnius do not pick up neutral red
and thus differ from the & of several insects which are said to encorporate
this dve ; oenocytes an -aid to stain supravitally with methylene blue, trypan
blue, and Bismarck bro i Ilollande. 1914; Poisson, 1924; Bogojavlensky, 1932;
Koch. 1945; Ocli.se. . (7) The granular hemocytes of Rhodnius do not
possess the bizarre shapes of those oenocytes of Rhodnius illustrated by YYiggle.s-
worth ( 1953. his Fi 239 g, h. and ki. nor do granular hemocytes possess the
spindle-shaped clefts or needle-like crystals which some of the oenocytes have
1 \\ iggles\\ nrtli's Kig. 239 e. f, h and i ). It is important to mention, however, that
Wigglesworth (personal communication) believes the granular hemocytes resemble
certain small oenocytes in stained preparations of Rhodnius (see, for example, his
Fig. 239 c and d). "
\Yith phase contrast microscopy, the granular hemocytes of Rhodnius resemble
the non-phagocytic granulated blood cells of many other insects (Poisson, 1924, see
his Fig. 21? Bogojavlensky, 1932; Millara. 1947; Jones, 1959 and unpublished i .
The granular hemocytes of Rliodnins do not closely resemble the oenocytoids of
Mysia (Ilollande, 1909). Melolontlm (Hollande, 1911), Psylliodes (Hollande,
1911 i. Galleria (. Metalnikov and Gaschen. 1922). Notonccta (Poisson, 1924). Cal-
H[>honi (Rooseboom. 1937), Prodenia (Yeager, 1945). Ephcstia (Arnold, 1952),
Tenebrio (Jones, 1954). Drosophihi (Rizki and Rizki. l t 59 < their "crystal cells").
Uninhy.r ( Xittono. 1960). or GalcruccUa (Jones, unpublished). Wigglesworth
( 1933 i stated clearly that the cells which we term gninuhir hemocytes have no con-
nection with the oenocytes of RJwdnius.
The cells which are termed the oenocytoids of Rhodnius ('and which Wiggles-
worth considers to be a variety of plasmatocyte) have the following characteristics
in common with the oenocytoids and/or oenocytes of many other insects: ( 1 ) they
are generally large, thick, often quite bizarrely-shaped cells, (2) they have one or
sometimes two nuclei with conspicuous nticleoli and a dense, often complexly tex-
tured cytoplasm. (3) they may occur in discrete clusters, and (4) they are not
numerous in the circulating hemolymph. They differ from stationary oenocytes
most conspicuously in not being eosinophilic cells. Whether the cells here identified
MS oenocytoids are related to or are derived from the stationary oenocytes of Rhod-
nius is not known. For a long time it has been claimed that oenocytes are capable
of budding off certain hcmocyte.s ( Koschevnikov, 1900; Kollman, 1908; Hufnagel.
1918; f'oisson. 1 ( >.24 i hut generally the investigators do not clearly distinguish be-
\veen small oenocytes. large plasmatocytes, granular hemocytes. or oenocytoids.
Several of the hcmocvte> of Khadnius might be secretory (Y.//., plasmatocx tes.
nular hemocytes, and oenocytoids). Various cytological criteria are needed be-
' can accurately assess the situation. Total and differential hemocvte counts
KJuxInhts will be presented in subsequent papers.
/ork was supported by Grant HE 05193 and Award 1 K-3-GM-21,529
from th National 'Institutes of Health. Bethesda. Maryland. Scientific Article Xo.
01 no. 3655 of the ^Faryland Agricultural Kxpenment Station.
HEMOCYTES OF RHODNIUS
I am indebted to Mrs. Daisy P. Liu for much help with some of the initi;
vations and for rearing the insects. I am particularly grateful to Sir '
SUMMARY
1. The hemocytes of R/iodniits f^rolLrns have been studied with phase contrast
microscopy, after supravital staining, and in fixed and stained smears.
2. With phase contrast microscopy, the following categories of circulating cells
can be readily identified: (a) non-dividing and mitotically-dividing prohemocytes,
(b) non-vacuolated and vacuolated plasmatocytes, (c) intact and quickly lysing
granular hemocytes, (d) oenocytoids with and without special cytoplasmic inclu-
sions, (e) adipohemocytes, and "fat body cells, and (f ) granulocytophagous cells.
3. This classification and terminology are compared with those of Wigglesworth.
It is suggested that the cell which Wigglesworth terms an oenocytoid is more com-
parable to the granulated blood cells of other insects and may be referred to as a
granular hemocyte. It is suggested that the cells which Wigglesworth refers to as
large non-granular spindle cells and nnn-phagocytic giant hemocytes are comparable
to the oenocytoids of other insects.
4. Yacuolation of plasmatocytes can be prevented by heat-fixing fed Rhodnius.
Lysis of granulocytes can be prevented by collecting hemolymph into 0.75 r r
Versene.
5. Attempts to correlate an increase in sizes of circulating plasmatocytes with
secretion of the thoracic gland hormone in fourth and fifth stage nymphs were not
successful because of the great variability in the sizes of these cells.
6. Since most circulating plasmatocytes in differential hemocyte counts of un-
fixed fourth stage nymphs were identified as the vacuolated type, no correlation was
possible between their vacuolation and the secretion of the thoracic gland hormone.
7. In unfed fifth stage nymphs, most of the circulating plasmatocytes were classi-
fied as vacuolated cells. Between the first and second days after the nymphs took
a blood meal, the percentages of plasmatocytes identified as vacuolated cells abruptly
LITERATURE CITED
ARNOLD, J. W., 1952. The haemocytes of the mediterranean flour moth, Ephcstia kuhniclLi Zell.
(Lepidoptera: Pyralididae). Canad. J. ZooL, 30: 352-364.
BOGOJAVLENSKY, K. S., 1932. [The formed elements of the blood of insects.] Arch. Rnss.
Auat.. Hist, ct Einhryiil.. Lcnini/nid. 11: 361-386 (in Russian).
HOLLANDS, A. C., 1909. Contribution a 1'etude du sang des Coleopteres. Arch. ZooL c.r/vr. cf
gen. (5 ser.), 2: 271-294.
HOLLANDS, A. C., 1911. fitude histolngique comparee du sang- des insectes a hemorrhee et des
insectes sans hemorrhee. Arch. ZooL c.vper. ct ijcn. (5 ser.), 6: 283-323.
HOLLANDK, A. C., 1914. Les cerodecytes ou "oenocytes" des insectes considered an point do vue
biochemique. Arch. Anat. Micros., 16: 1-66.
HUFNAGEL, A., 1918. Recherches histologique sur la metamorphose d'un Lepidoptere (Hyfo-
noincnta padella L.). Arch Zool. exper. et gen., 57 : 47-202.
JONES, J. C., 1950. The normal hemocyte picture of the yellow nu'iiKvurm, Tcnchrio inolitor
Linnaeus. loiva State Coll. J . ScL, 24 : 355-361.
JONES, J. C., 1954. A study of mealworm hemocytes with phase contrast microscopy. Ann.
Ent. Soc. Aincr., 47 : 308-315.
.1 \CK COLVARD JONES
JUNES, J. C., 1959. A phase contrast .study of the blood-cells in I'mdcnin cridania (Order
Lepidoptera). Quart. J. Wicr. Sci., 100: 17-23.
JONES, J. C, 1962. Current concepts ning insect hemucytes. .liner. 7,ool., 2: 209-249.
KIHH. J., 1945. Die Oenocyten von Drosnpliilii mclanotjaster. Rcr. Snissc Zool., 52: 415-420.
KOI. i. MAX, M., 1908. Recherches sui les leucocytes et le tissue lyni|)lioidc des invcrtebres. Ann.
Soc. Nat. Zool, 9 : 1-238.
ECos< IIEVXIKOV, G. A., 1900. Vcbet den Fettkorper und die Oenocyten der Honigbiene (Apis
mcllijcra L.). Zool. , in;., 23: 337-353.
MKTAI.XIKOV. S.. AND H. GASCIIEN, 1922. Immunite cellulaire et luiniorale cliez la chenille.
Ann. Inst. I'astcur, 36: 231-252.
MILLARA, P., 1947. Contribution a 1'etude cytologique et physiologique des leucocytes d'insectes.
Hull. Soc. France et !<cl<n,,uc (Paris), 81: 129-153.
XITTOXO, V., 1960. Studies on the blood cells in the silkworm, Boinhy.r inori L. Bull. Scricnlt.
/:.r/\ Stut. ( Tokyo), 16 (4) : 171-266 (in Japanese, with English summary).
OCHSE, \Y., 1946. Untersuchungen iiber die Oenocyten von Sialis Intaria L. Rcr. Sitisse
Zool, 53: W-71.
POISSON, R., 1924. Contribution a 1'etude des Hemipteres aquatiques. Bull. Biol. France ct
Bchjiquc, 58 : 49-305.
Pi'VAKKOKF, E., 1910. Recherches histologiques sur la metamorphose d'un Coleoptere (la
galerque de Tonne). Arch. Aunt. Micros.. 12: 333-474.
RIZKT, M. T. M.. ANT) R. M. RI/KI, 1959. Functional significance of the crystal cells in the
larva of Drnsophilii iiiclan/n/astcr. J. Binfhys. Cytol., 5: 235-240.
ROOSEBOOM, M., 1937. Contribution a 1'etude de la cytologie du sang de certains insectes, avec
quelques considerations generales. Arch. Nccrl. Zool.. 2: 432-559.
\\'ir.c,i,Ks\voKTn, V. B., 1933. The physiology of the cuticle and of ecdysis in Rhodniits proli.vnx
(Triatomidae, Hemiptera) ; with special reference to the function of the oenocytes and
of the dermal glands. Quart. J. Micr. Sci., 76: 269-318.
\YIGM.ESWURTH, V. B., 1953. The Principles of Insect Physiology. E. P. Button, New York,
546 pp.
YYiGGLESWORTii, Y. B.. 1 U 55. The role of the haeniocytes in the growth and moulting of an
insect. Kluxhiins proli.vus (Hemiptera). /. E.vp. Biol., 32: 649-663.
WIGGLES WORTH, V. B., 1956a. The function of the amoebocytes during moulting in Rhodiiius.
Ann. Sci. Nat. Zool., 18: 139-144.
\VIGGLESWORTII, V. B., 1956b. The haemocytes and connective tissue formation in an insect,
Rhodnins proli.vus (Hemiptera). Quart. J. Micr. Sci., 97: 87-98.
YKAGKR, J. F., 1945. The blood picture of the southern armyworm (Prodcnia cridania). J
Auric. Rex., 71 : 1-40.
EVIDENCE FOR TRANSAMINASE ACTIVITY IN THE SLIME MOLD,
DICTYOSTELIUM DISCOIDEUM RAPER *
JEROME O. KRIVANEK AND ROBIN C. KRIVANEK
Department of Zoology, University of South Florida, Tampa, Florida 33620
As the developmental cycle of the slime mold, Dictyostelium discoidcmn Raper,
proceeds from the myxamoeba stage to the mature sorocarp stage, there occurs a
reduction in proteinaceous materials and an increase in polysaccharide carbohydrate,
as shown by Gregg, Hackney and Krivanek (1954) and Gregg and Bronsweig
(1956). On the basis of these quantitative studies, Gregg and his associates sug-
gested that the protein components may serve as precursors not only for energy-
source intermediates of development, but also for the synthesis of carbohydrate nec-
essary for stalk formation. Attempting to define the metabolic mechanisms respon-
sible for this inverse relationship, Krivanek and Krivanek (1959) chromatographi-
cally analyzed the amino acid components of the slime mold in both hydrolyzed and
unhydrolyzed tissue. Their findings suggested that deamination may be one
process relating protein degradation to carbohydrate synthesis. These authors did
not exclude the possibility, however, that other metabolic mechanisms, e.g., trans-
amination, may be instrumental in this linkage.
Utilizing a spectrophotometric technique to observe the change in the charac-
teristic absorption band of DPNH at 340 m/x, Wright and Anderson (1959) demon-
strated the occurrence of "aspartic-pyruvic transaminase." However, these au-
thors, as well as others (Meister, 1950; Aspen and Meister, 1958), have expressed
the lack of definity of such an analytical technique because of its broad specificity.
In view of the important role which transaminase activity plays in relating pro-
tein and carbohydrate metabolism, more precise evidence than that thus far pre-
sented would seem desirable. It is therefore the intent of this paper to demonstrate
that specific transaminase activities are indeed operative in the slime mold, Dictyo-
stclhnn discoidcum.
MATERIALS AND METHODS
D. discoidciiin was cultured in the manner described by Bonner (1947), using
Escherichia coli as the bacterial associate.
The following two transamination reactions were studied :
Reaction I : glutamate + pyruvate a-ketoglutarate + 1-alanine
Reaction II : glutamate + oxaloacetate a-ketoglutarate -f 1-aspartate
The primary technique employed in studying these reactions was that of progressive
chromatography as described by Hird and Roswell (1950).
1 This research supported by Grants G-1908 and G-14422 from the National Science
Foundation.
295
296 J. (). Kkl\. \.\TK AND R. C. KKIVANKK
I iidi\ idnals in the desired stag* i \eiopment were harvested from the Petri
j)lates and homogenized in ice-cole >>phate buffer, pi [ 7.4, using an homogenizer
of the type described by Gregg . 54). The final volume of the homogenate
was 5 nil. The extent of /ation was determined by microscopic inspec-
tion t the In miogenatc.
After centrifugal ion. o1 :omogenate. the supernatant or soluble fraction (S)
was withdrawn from tl culate centrifugate or insoluble fraction (I). Hoth
fractions were then madf up to the original volume of 5 ml.
One-mi, samples oi .raction were then transferred to five separate reaction
tubes live tubes for each fraction series. To the control tube in each series was
added 1 ml. of phosphate buller only. To each of the remaining four tubes in each
series were added ., ml. glutamate and \ ml. oxaloacetate or pyruvate, depending
upon the reaction under consideration. The concentration of the glutamate,
oxaloacetate and pyruvate varied and will be discussed under Results. To this
point all step- were carried out under ice-cold conditions.
It is conceivable that 1-alanine may be formed from pyruvate. 1-aspartate from
oxaloacetate, and a-ketoglutarate from glutamate by reactions other than trans-
amination. Therefore, supplementary controls were utilized to determine whether
the appearance and disappearance of the appropriate substrates were mutually inter-
dependent. In this particular control series, only one of the initial reactants, i.e.,
glutamate, was added to the reaction tubes, with subsequent treatment of these
controls being the same as for the phosphate buffer controls and the experimental
series.
Immediately upon the addition of the last substrate, the reaction tubes were put
into a closed anaerobic environment, consisting of gaseous nitrogen and pyrogallol.
and the mixtures were allowed to react at a temperature of 37 C. Reaction tubes
from both soluble and insoluble series were generally removed after 30, 120, 180
and 240 minutes and processed. Control tubes were processed in the same man-
ner and for the maximum time interval.
At the end of each incubation period, to each of the tubes were added two
volumes of warm ethanol (60-70 C.) to precipitate the proteins. After centrifu-
gal ion, the supernatant fluid was withdrawn and dried //; raciio at room tempera-
ture. The residue after evaporation was then resuspendecl in 1 ml. of distilled
water, and identical fractions from each preparation were spotted on Whatman No.
1 filter paper for a uni-directional chromatographic separation of the amino acids.
Among the various solvents used were: propanol-water (80:20), n-butanol-acetic
acid-water (250:60:250), n-butanol-acetone- water (10:10:5), and n-butanol-ace-
tone-water (5:4:1 ). Development of the spots was accomplished by means of spray-
'he chromatograms with a solution of 0.3% ninhydrin in 95% ethanol. Identifi-
cation of the unknown spots was determined by means of positional comparisons
-'ecu the unknown spots and spots nf known amino acids applied to the same
pol determination of the alpha-keto acids (oxaloacetate, alpha-ketoglutarate
ruvate) was done by .separating them as their 2,4-dinitrophenylhydrazones
- method described by Block, Durrum and Zweig (1 ( >58). To sam-
ple- of reaction mixtures, after deproteinization with warm ethanol, was
added 1 ml. < J.I dinitrophenylhydrazine dissolved in 6 N HC1. After 30
TRANSAMINATION IN DICTYOSTEl.il M
minutes' standing at room temperature, the hydrazones were extracted in
tory funnel with three 7|-ml. washes of a chloroform : ethanol (80:20) solul-
The hydrazones. now in the latter solution, were then extracted with 7\ ml. of '.
Na 2 CO 3 . After washing the hydrazone-containing Na 2 CO 3 solution with 5 ml. o
chloroform-ethanol solution, the Na 2 CO.,, solution was then acidified with 2\ ml
6 N HC1 in the cold. The resultant acidified Na 2 CO : . solution was further washc-d
with three portions of the chloroform: ethanol solution totaling 10 ml. The 10 ml.
of washings were then evaporated under a gentle air stream.
For a chromatographic separation of the 2,4-dinitrophenylhydrazones, the resi-
due after evaporation was dissolved in 2 ml. absolute ethanol and spotted on What-
man No. 1 filter paper in !-/*!. amounts. Identification of the spots was determined
by preparing samples of known alpha-keto acids, processing them in the same man-
ner as the experimental series and spotting them on the same paper with the
experimental s.
Detection of the hydrazones of the keto acids was accomplished by initially in-
specting the chromatogram for yellow spots (distinctive of hydrazones), then spray-
ing the paper with a 2% ethanolic KOH solution which imparts a red-brown color
to the spots, and/or scanning the paper with a UV light which caused the spots to
fluoresce.
Since the paper chromatographic method did not afford a clear separation be-
tween glutamate and aspartate, a paper electrophoresis procedure was utilized
(Block, Durrum and Zweig, 1958). This method is specific in its separation of
aspartate, glutamate, histidine, arginine, lysine, and the monoamino-monocarboxylic
acids. A phthalate buffer, pH 5.9, was used in a Spinco paper electrophoresis appa-
ratus usually run at 500 volts, 18 amperes for three hours.
K'Ksri/rs AND DISCUSSION
. /. Amino acids
Figure 1 shows the chromatographic results of Reaction I, i.e., when tissue
fractions, soluble and insoluble, were incubated in the presence of 1/40 i\I glu-
tamate and 1/10 J\I pyruvate. It is to be noted that with lengthening periods of
incubation (A is shortest, D is longest), color intensities of the glutamate spots
decrease in both soluble and insoluble series. No corresponding spots were evi-
dent in the control series which were incubated for four hours the maximum time
for the experimental series. The appearance of alanine in the insoluble series lagged
behind its appearance in the soluble series. Thus, after two hours' incubation
alanine was first seen in the former series while only 30 minutes were necessary for
it to appear in the soluble series.
The results relative to Reaction II are seen in Figures 2 and 3. In Figure 2,
the spots of aspartate and glutamate in the soluble series are in close spatial rela-
tionship to each other, with aspartate trailing glutamate. The chromatographic
technique did not clearly delineate the two compounds although development of the
chromatogram with dicyclohexylamine did allow better interpretation than did nin-
hydrin. It is to be noted that aspartic acid increased in intensity in the soluble
series. A corresponding decrease in the intensity of glutamate was also evident.
In the insoluble series, no aspartate was apparent in either the chromatographic or
298
T. O. KKIVAXKK AND R. C. KRIVANEK
INCREASING
INTENSITY
o o
DECREASING
INTENSITY
o
o
A B C D E
s s s s s
INCREASING
INTENSITY
DECREASING
INTENSITY
o
A i B i C r D i E i
GLU ALA
FIGI RE 1. Exact reproduction of chromatogram showing amino acid results of Reaction I.
Incubation times: A series, -1 hour; B series, 2 hours; C series, 3 hours; D series, 4 hours;
K Aeries (phosphate control), 4 hours. "S" denotes soluble fraction, "I" denotes insoluble frac-
tion, GLU glutamate known; ALA = alanine known.
INCREASING
INTENSITY
x
o D o
*l^.
INCREASING
INTENSITY
o o
o,
f\ ' ' ' \
'-' I / v/
' i
B s C s D s E s A , B i C i D r E i
ASP GLU ALA
MI.' iix;n oduction of cbroniato^rani shoxvini; amino acid results of Reaction
Incubation times same as in iM.uun- 1. ASP aspartate known.
TRANSAMINATION IN DICTYOSTELIL'M
299
GLUTAMIC
ASPARTIC
oc-ALANINE
FIGURE 3. Exact reproduction of electrophoretic pattern showing amino acid results of
Reaction II. Length of run: 3 hours; voltage: 500; amperage: 18 amps. Veronal buffer of
pH 8.6. Letter notations same as in Figure 1.
electrophoretic determinations. It should he mentioned at this point that no de-
crease in color intensity of glutamate was observed when 1/20 J\I concentration was
used. When 1/40 ,17 glutamate was used, a perceptible decrease was evident.
However, this decrease was less profound than in Reaction I.
In addition to the expected aspartate product of transamination Reaction II.
an unexpected product alanine was also present in both soluble and insoluble
series. No alanine was detected in the control series. The appearance of alanine
could be accounted for by way of oxaloacetic acid being decarboxylated to pyruvic
acid, with transamination subsequently occurring to form alanine. Such a trans-
formation could be mediated only through the action of a decarboxvlnse.
The chromatographic separation of alanine, aspartic acid, and glutamate was
supplemented by an electrophoretic separation. Using the electrophoretic technique
previously described for the separation of monoamino-monocarboxylic amino acids,
complete validation of the chromatographic results was accomplished as shown in
Figure 3. A decrease in glutamate intensity and increase in alanine and aspartic
acid intensities were noted.
B. Kcto-acids
The keto-acid determinations essentially follow expectation if transamination is.
in fact, operative in the slime mold.
W .1. ( ). KRIVANEK AND R. C. KRIVAXKK
\\hen tissue extracts were incubated in 1/40 .17 glutamatc and I/ 10 .17 oxalo-
acelic acid, Reaction II, tin resul shown in Figure 4 were achieved. Alpha
ketoglutarate, one of the end pru i the reaction; is seen to increase in intensitx
with increasing tinu- of incuh: of the tissue. The decree of color intensity of
the soluble series reniaiiu ^lier than that in the insoluble series. However,
oxaloacctate. one of tin ' reactants, did not display any reduction in intensity
as might have been exp< Since our method did not distinguish between pyru-
vate and oxaloacetate ! s i^nre 4), pyruvate may have been generated during the
course of the reaction would again not be unreasonable in view of the previ-
ouslv stated possibil!i\ that oxaloacetate may be decarboxylated to yield pyruvate
in the slime mold.
Various concentrations of oxaloacetate were used in addition to the 1/10 il/ con-
centration. When a lower concentration (1/20 .17) was used, no spot was evident
at the 1 oxaloacetate locus chromatographically. In addition, the enzymatic conver-
sion of this substrate took place rapidly, for alpha-ketoglutarate appeared after only
15 minutes of incubation. Increasing the concentration of oxaloacetate to 1/5 .!/
seemed to have an inhibitory effect on the reaction, as indicated by (1) large spots
at the oxaloacetic acid locus, (J) extremely small ketoglutarate spots, and (3) no
alanine or aspartic acid being formed. ( hi the basis of these test concentrations.
1/10 .17 oxaloacetate was chosen as being the optimal concentration.
Figure 5 shows the results of incubating homogenized tissue with 1/40 M glu-
tamic acid and 1/10 .17 pyruvate. Here, as in the case of Reaction II, alpha-
ketoglutarate increased in color intensity with increasing lengths of incubation time-.
008
INCREASING INCREASING
INTENSITY INTENSITY
O C?
B s C s D s E s A t B T Cj D, E,. oC-KETO OXAL PYR MESO
GLUT ACET
\. I ; .\,K t ic]ii (idiu-tinn of chromatogram shoxvins koto-arid n-Milts of Reaction II.
on tiii]i'> sanu- as in Figure 1. a-KKT( )( il.L"!' = a-ketoglutarate known: ()X.\I..\CET
! kiio\\n; \'\\\ -- pyruvic acid known; MI-'.SO mcsoxalic acid known.
Meso .u'id known was spotted 1o aid idrnlit'ication of nnknoun spots. Note lori of nn-
kn< iv noin) -, of -pot application.
TRANSAMINATION IN DICTYOSTELIUM 301
oooo o
INCREASING INCREASING
INTENSITY INTENSITY
d tf & o
o
A, B. C D. E. A, B T C D, E, OC-KETO PYRUV
S S S S S I T I I I
GLUT
FIGURE 5. Exact reproduction of chromatogram showing keto-acid results of Reaction I.
Incubation times same as in Figure 1. Abbreviations same as in Figure 4.
With pyruvate, as with oxaloacetate at this concentration, no progressive diminution
in color intensity occurred with increasing lengths of incubating times. Similar
reasoning and possible concentration effects can be applied to this event as were
applied to the oxaloacetate results.
Brief mention should be made of two unidentified spots evident only in Reaction
II experiments. Their possible importance lies in the fact that they occurred only
in the experimental series and were not evident in the controls. The locus of "spot
A," when present, was invariably midway between the point of origin (point of ap-
plication of the test solution on chromatogram) and the alpha-ketoglutarate locus.
Although every attempt was made to reproduce exact conditions between each run,
"spot A" was not always detected, occurring more times than not. It appeared
when using 1/20 M and 1/10 M concentrations of oxaloacetic acid.
The second unidentified spot, "spot B," was consistently present, its locus being
at or slightly above the points of application of the experimental samples on the
chromatogram (see Figure 4). The various concentrations of oxaloacetic acid did
not affect its appearance. Not only was it present in all test series, but there was
also a tendency for it to increase in color intensity with increasing incubation times.
Its absence from the controls and from the point of application of a known oxalo-
acetic acid solution is to be especially noted. The significance, if any, of unidenti-
fied "spots A and B" is at present not apparent.
SUMMARY
Progressive chromatography and paper electrophoresis techniques have demon-
strated qualitatively the occurrence of two transaminating systems in the slime mold,
Dictyostelium discoideinn. These systems are glutamic-aspartic (or glutamic-
302 j. o. KRIVANEK: AND R. C. KRIVANEK
oxaloacetic) transaminase and glutamic-alanine (or glutamic-pyruvic) transaminase.
However, in experiments designed to demonstrate the glutamic-aspartic trans-
aminase, alanine was also produced, indicating the presence of an oxaloacetic-pyruvic
decarboxylase. The evidence for transaminases confirms the existence of pathways
for the conversion of protein to carbohydrate in the slime mold.
LITERATURE CITED
ASPEN, A. J., AND A. MEISTER, 1958. Determination of transaminase. In: Methods of Bio-
chemical Analysis, Vol. VI. Interscience Publishers, New York. Pp. 131-161.
BLOCK, R. J., E. L. DURRUM AND G. ZWEIG, 1958. A Manual of Paper Chromatography and
Paper Electrophoresis. 2nd Edition. Academic Press, New York.
BONNER, J. T., 1947. Evidence for the formation of cell aggregates by chemotaxis in the
development of slime mold Dictyostclium discoidcum. J. E.rp. Zoo/., 106: 1-26.
GREGG, J. H., AND R. D. BRONSWEIG, 1956. Biochemical events accompanying stalk formation
in the slime mold, Dictyostclium discoidcum. J. Cell Comf>. Physiol., 48: 293-300.
GREGG, J. H., A. L. HACKNEY AND J. O. KRIVANEK, 1954. Nitrogen metabolism of the slime
mold Dictyostclium discoideum during growth and morphogenesis. Biol. Bull., 107:
226-235.
HIRD, F. J. R., AND E. V. ROSVVELL, 1950. Additional transaminations by insoluble particle
preparations of rat liver. Nature, 166: 517-518.
KRIVANEK, J. O., AND R. C. KRIVANEK, 1959. Chromatographic analyses of amino acids in the
developing slime mold, Dictyostelium discoidewn Raper. Biol. Bull., 116: 265-271.
MEISTER, A., 1950. Reduction of a, 7-diketo and a-ketoacids catalyzed by muscle preparations
and by crystalline lactic dehydrogenase. /. Biol. Chcm., 184: 117-129.
WRIGHT, B. E., AND M. L. ANDERSON, 1959. Biochemical differentiation in the slime mold.
Biochim. Binphys. Acta, 31: 310-322.
THE OVARY AND ANAL PROCESSES OF "CHARACODON"
EISENI, A VIVIPAROUS CYPRINODONT
TELEOST FROM MEXICO 1
GUILLERMO MENDOZA
Biology Department, Grinnell College, Grinnell, lozva
Early classifications of the Mexican fishes of the family Goodeidae, such as those
of Jordan and Evermann (1896-1900), Meek (1902, 1904), Regan (1906-1908)
and Hubbs (1924, 1926), were based largely on characteristics concerned with the
type of jaws, teeth, length of intestine, etc. Actually, many of the species were
placed in genera now included in entirely different families, such as the Poeciliidae.
Meek recognized the natural relationships of the Goodeidae, using such criteria as
(1) viviparity, (2) specialization of the anal fin, and (3) geographic distribution,
although he continued to base his classification on the older criteria.
In 1939 Hubbs and Turner revised the taxonomic structure of the goodeids,
basing the new classification primarily on characteristics of the ovarian structure
and the trophotaeniae, processes extending from the peri-anal region in the embryo
and assumed to be used for respiratory and nutritive functions during gestation.
The authors concluded that the ovarian and trophotaenial characters indicated the
lines of phyletic relationships better than previously used taxonomic schemes. This
new classification has been used by workers since 1939. However, De Buen pub-
lished a key to the family (1942-1943) in which he used the Hubbs-Turner criteria
to distinguish genera but reverted to the more usual characteristics to distinguish
species. On the other hand, in his recent key to the fishes of Mexico, Alvarez
(1950) used the customary taxonomic features but did not refer to the Hubbs-
Turner criteria.
Recently there has been some question about the validity and classification of
"Characodon" eiscni Rutter, synonymized by Hubbs and Turner (1939) with
Characodon variatus (= Xenotoca variata} of previous classifications (Meek, etc.).
The need for a careful study of this species was suggested to me by Robert R.
Miller of the University of Michigan. It was agreed that I would examine the
ovary and trophotaeniae whereas Dr. Miller would reappraise the taxonomic position
of the species on the basis of other characters. For various reasons, it has been
decided that this portion of the study should be published now, to be followed later
by Dr. Miller's taxonomic analysis.
In the process of comparing the ovarian and trophotaenial characteristics of
"Characodon" eiscni and Xenotoca variata, certain discrepancies in structure have
become apparent to the writer: (1) there are serious differences in the ovarian and
trophotaenial structures of the species described here, "Characodon" eiseni, and
those of Xenotoca variata with which it has been synonymized by Hubbs and Turner
1 This study was supported by Grants No. G16726 and GB2378 of the National Science
Foundation.
303
304
(iUILLER.MO MKNDOZA
POSTERIOR
MEDIAN
PROCESS
I mm
LATERAL
PROCESSES
PLATE I
ANTERIOR
MEDIAN
PROCESS
OVARY AND PROCESSES OF C. EISENI 305
(1939) ; (2) regardless of the identity of the species, lack of agreement between the
ovarian and trophotaenial structures calls into question the applicability of the
Hubbs-Turner criteria in this particular species.
THE GOODEID OVARY AND TROPHOTAENIAE
The ovary of the goodeid fishes is a single, hollow, spindle-shaped structure, con-
tinuous posteriorly with the oviduct which in turn opens to the outside at the genital
pore immediately behind the anus. The ovary is further divided into two lateral
halves by a median vertical septum. The nature of the median septum is very
important in the Hubbs-Turner classification scheme. The septum may be single,
complex and attached at the mid-dorsal and mid-ventral lines as in Alloophorus
robustus and Goodca luitpoldii (Plate I, Fig. 1) or it may be divided into dorsal
and ventral halves as in Xenoophorus captivus and Neoophorus dlad (Turner, 1933 ;
Hubbs and Turner, 1939). The halves may then be long or short and may be
rolled in one lateral direction or the other ; other variations occur. A second im-
portant characteristic of the ovary is the location of the ovigerous tissue. Eggs may
be found in the walls of the ovary (e.g., Alloophorus robustus (Plate I, Fig. 1) ; in
some species they may also be found in the septum (Goodca luitpoldii and others).
In species such as Neotoca bilineata (Plate I, Fig. 2), the median septum is thin
and bears no eggs ; germ cells are restricted to two lobulated folds that protrude into
the ovarian lumen from the dorso-lateral walls of the ovary (Turner, 1933; Men-
doza, 1940).
In addition to these characteristics, the trophotaeniae were also used by the au-
thors in the classification of the species. These trophotaeniae usually are exten-
sions of the peri-anal lips and may occur in one of two basic forms ; they may have
the form of a small flower or "rosette" as in Goodea luitpoldii (Plate II, Fig. 6),
Neoophorus diasi and Allotoca dugcsii (Turner, 1937, Hubbs and Turner, 1939),
or they may have the shape of a ribbon, the number of ribbons varying with the dif-
ferent species. For example, Characodon lateral-is (Turner, 1937) and Hubbsina
turneri (Mendoza, 1956) have only two posteriorly directed processes (Plate II,
Fig. 8) ; Neotoca bilineata (Turner, 1937) and others have three processes in the
form of a "trident" extending caudad (Plate II. Fig. 7), but Zoogoncticus cuit-
seocnsis (Plate II, Fig. 11), on the other hand, has 10 to 12 processes (Turner,
1937). Furthermore, the ribbon-shaped processes may be sheathed, in which case
the epithelium of the process is separated from the central medulla by a space as in
Neotoca bilineata and Skiffla Icnnac (Plate III, Figs. 12-13). In non-sheathed
FIGURES 1-2. Diagrammatic transverse sections of two goodeid ovaries (from Hubbs and
Turner, 1939) to show the basic structure of the ovary and the location of the ovigerous tissue.
Eggs are shown in black.
FIGURE 1. Alloophorus robustus.
FIGURE 2. Neotoca bilineata.
FIGURE 3. A section of an immature ovary of "Characodon" ciscni. showing a large number
of eggs in the anterior region where the median septum is not well formed.
FIGURE 4. A section of a mature post-partum ovary of "Characodon" ciscni. showing few
eggs in the ovarian wall and a much-folded median septum. Figures 3 and 4 are tracings from
photographs ; in these figures the ovarian lumen is stippled.
FIGURE 5. The trophotaeniae of "Characodon" ciscni. The sheathed nature of the processes
shows clearly. The drawing is a tracing of a photograph.
306
GLJILLKRMO MENDOZA
8
PLATE II
FIGI-RKS 6-11. Representative types of trophotaeniae from different oodi-id Buries. All
figures except 9 arc taken from Hubbs and Turner (1939).
FIGURE 6. Goodca hiitpoldii.
FIGURE 7. Neotoca bilineata.
FTCURK 8. Characodon latcralis.
OVARY AND PROCESSES OF C. EISENI 307
processes found in species such as Alloophorus robustus (Plate III, Fig. 14),
Zoogoncticus cuitzeocnsis, etc., the epithelium is immediately adjacent to the central
core; there is no subepithelial space (Turner, 1937; Hubbs and Turner, 1939).
MATERIALS AND METHODS
All specimens used in this study, living and preserved, were obtained from
Robert R. Miller, Curator of Fishes, Museum of Zoology, University of Michigan.
The material examined came from the Manantial "El Sacristan" at Tepic, Nayarit,
near the type locality for Rutter's species. The writer expresses his gratitude to
Dr. Miller for the specimens, for the suggestion that this study be made and for
valuable suggestions made during the writing of this manuscript.
The description of the ovary in the present paper is based on a study of approxi-
mately 75 gonads. Over 40 ovaries from preserved specimens were studied in toto ;
the others were sectioned, stained by standard techniques and examined microscopi-
cally. The nature of the median septum is best analyzed in a whole gonad by re-
moval of the embryos and by examination of the entire organ under a dissecting
microscope. Analysis of the septal structure solely from microscopic sections would
be very tedious at best and probably very unreliable. For the study of the proc-
esses, at least 200 embryos were examined, ranging from neural tube stages to speci-
mens ready for birth (13-14 mm.) ; observations were made on living, preserved
and sectioned specimens. Since the processes undergo serious changes just prior
to birth, it is imperative that description of the processes be based on embryos less
than maximum size.
OVARY
Gross structure
The ovary is a spindle-shaped organ attached by a strong band of connective
tissue to the anterior wall of the body cavity. Two median mesenteries further sup-
port the ovary ; one is a very short membrane to the pigmented roof of the coelom,
the other is a long mesentery to the posterior section of the gut.
In a mature female the resting ovary normally measures 2-3 mm. in diameter;
the length of the combined ovary and oviduct varies from 10-30 mm., depending
on the size of the female. A gonad with developing embryos varies according to
the size of the female and the age and number of the contained young. A repre-
sentative measurement of an ovary of a 55-mm. female with embryos 11-13 mm.
long is 20 X 10 mm. (length by diameter).
The ovary is a typical goodeid ovary ; it has a muscular wall, a central lumen
and a median septum (Plate I, Figs. 3-4). The gonad is divided approximately
into equal halves by a much-folded longitudinal, median septum This membrane
is quite variable in its structure for it may be complete, only partially complete or
fully divided into dorsal and ventral halves. A complete septum is one that ex-
tends the length of the ovary as a single, continuous sheet. However, the septum
FIGURE 9. "Characodon" ciscni. This is a semi-diagrammatic, ventral view of the processes
in Figure 5.
FIGURE 10. Xenotoca variata.
FIGURE 11. Zoogoncticus cuitseoensis.
GUILLEKMO MENDOZA
process epithelium
sheath space
medulla
12
0.1 mm
13
I'l.ATE III
14
FIGURES 12-14. Sections of trophotaeniae of three goodeid species. All drawings are
tracings from micropr ejections.
FIGURE 12. Ncntoca bilmcata (11 mm.). Note the delicate epithelium and the generoti>
sheath space around the medulla.
FIGUUK 13. Skiffia Icnuae (6 mm.). Sheathed processes similar to those of Neatnc,!
bilineata.
FIGURE 14. .!// Chorus ri>t>ustus (10 mm.). The process epithelium is thick; the sheath
space is absent.
OVARY AND PROCESSES OF C. EISENI 309
may be complete but perforated by one or more openings of various sizes, usually
at the posterior end. If partially complete, the septum is normally intact in the
anterior region but is divided into dorsal and ventral halves in the posterior region
of the ovary. All possible gradations occur in the degree of completeness of the
septum; as little as 25% or as much as 90% of the septum may be intact. If the
septum is not complete, it is divided into dorsal and ventral components which may
be approximately equal in size or markedly unequal. Among the 43 dissected
specimens the following variations in the septum were found :
TABLE I
Structure of the median septum
Number of ovaries
Condition of median septum
12
13
14
4
Complete; intact the full length of the ovary.
Partially complete; some perforations and partial division into dorsal and
ventral halves.
Divided into two complete and equal halves.
Divided into two complete but unequal halves.
Despite variations, the total height of the septum is much greater than the diameter
of the ovary, thereby throwing the septum into many folds. Side extensions or
branches of this membrane are numerous.
Ovigerous tissue occurs more often in certain locations but it is also quite varied
in its distribution. Eggs invariably are found in the anterior half or third of the
ovary although they may extend throughout most of the gonad in juvenile speci-
mens. Eggs occur in the ovarian wall and in the septum but more often they are
found in the anterior, ventral and lateral walls of the ovary. Eggs that occur in
the septum are confined primarily to the ventral edge but they may occur anywhere
along the septum (Plate I, Fig. 3).
Histology
Histologically, the mature ovary resembles other goodeid ovaries (Turner,
1937; Hubbs and Turner, 1939; Mendoza, 1940, 1956). In a non-gravid ovary
both the septum and the internal walls are extensively folded. The stroma of the
gonad is formed of a delicate network of collagenous, mesenchyme-like connective
tissue that contains the many eggs and, in mature ovaries, many large blood vessels.
A large artery and vein follow a path along the mid-dorsal and mid-ventral lines of
the gonad. embedded in the muscular wall. The internal epithelium is sqviamous
or low cuboidal ; nuclei are large, rounded and vesicular. The epithelium evidently
does not attain the elaborate structure found in Neotoca bilineata (Mendoza, 1940).
A very extensive capillary plexus lies in a sub-epithelial position in the septum and
in the internal ovarian wall ; the plexus is very conspicuous in the mature ovary
but poorly developed in the immature gonad. Nests of early oogonia occur in the
ovarian wall and the septum ; eggs attain a maximum size of 250-300 /*. The fol-
licle that surrounds each egg is squamous in smaller eggs but columnar to compound
in eggs of maximum size. A thin vascular connective tissue "theca" surrounds
310
GUILLERMO MENDOZA
each follicle. A spongy or tumescent condition of the ovary occurs only in early
stages of development ; in advanced stages of gestation the ovarian walls and septa
are thin and collapsed. The muscular wall of the mature gonad is very thick and
is formed of smooth muscle and connective tissue. In the ovary proper the muscle
cells tend to run in a circular manner but there is much random orientation ; actual
whorls of cells and longitudinally oriented cells occur at random in the muscular
layer. A heavy layer of connective tissue borders the muscle layer on the external
and internal surfaces ; connective tissue fibers also occur in the muscle layer. In
the juvenile ovary the muscular wall is very thin. In the region of the oviduct, the
smooth muscle cells in the wall are arranged in two orderly layers ; one is longi-
tudinal, narrow and external in position, the other is circular, wide and internal.
TROPHOTAENIAE
There are four basic processes ; one is median in position and anterior to the
anus ; the other three extend posteriorly ; two are lateral and one is median and
posterior to the anus (Plate I, Fig. 5). Any one process may be modified, degener-
ate or completely missing. Any process may be secondarily split, the point of bifur-
cation occurring at a proximal or distal position along the process. Splitting is
more likely to take place in one rather than in two or more processes at one time
and, although splitting may be found in any process, the total number of ribbons
seldom exceeds six. Sometimes two or even three of the processes arise from
one common base.
The anterior process is invariably short ; the posterior median process tends to be
the longest but the lateral processes approach or may even exceed it in length. At
the point of maximum development, one or more of the processes extend to the
caudal fin and often extend beyond the tip. This size relationship is true for embryos
at all lengths, 6 mm. or 13 mm. The following examples are illustrative of proc-
esses in embryos 12-13 mm. long. The maximum length recorded for any process
was 7.5 mm. in a 13-mm. embryo ready for birth. The maximum length is normally
retained until time for birth although embryos frequently begin to resorb the
processes even before birth ; some specimens just prior to birth have been observed
with processes that extend only to the anal fin. Processes normally measure 0.3-0.4
mm. in typical maximum width although some of 1.0 mm. have been observed in
exceptional cases. At optimal development, processes appear turgid, smooth, trans-
lucent ; as birth approaches, they become compact, less translucent and have a
"furry" appearance.
TAIH.I. 1 1
tij anal processes in millimeters
Specimen
Anterior median
Right latt-i.il
I-ci't lateral
Posterior median
1
1.5
4.5
5.0
4.5
2
1.5
5.5, 6.5
5.5
6.0, 5.0
3
1.5
6.5
6.0
6.0, 7.0
1
2.5
5.5
6.0
5.0
5
1.0, 1.0*
5.0
4.0, 4.0
5.0
|)oi!l)le figures indicate split processes.
OVARY AND PROCESSES OF C. EISENI
311
Processes are unquestionably sheathed; a central medulla is separated by a
sheath space from the epithelial covering (Plate I, Fig. 5). The sheath is normal for
specimens up to stages approaching birth ; at this time, the characteristic may be lost.
The sheath characteristic may be visible even in the proximal peduncle that forms
the base of the processes. The sheath space may be extensive and continuous or
broken up into smaller vesicles (Plate IV, Figs. 16-17). The medulla or core
IS
16
PLATE IV
FIGURE 15. Trophotaeniae of Goodca Initpoldii (8 mm.). This "rosette" type process has
a large sheath space in small embryos but the space is absent in older embryos.
FIGURES 16-17. Trophotaeniae from two 8-mm. specimens of "Characodon" eiseni. The
epithelium shown is thick ; the sheath space is variable in appearance ; it is generous, restricted or
absent in some regions. All figures are tracings from microprojections.
312 GUILLERMO MKXDO/A
normally measures 0.16-0.24 mm. in maximum width although some measurements
of 0.35 mm. have been noted. The medulla is normally attached to the dorsal
epithelium although it may attach to any area of the epithelium. On occasions, the
medulla may even protrude beyond the surface of the process, carrying the process
epithelium out with it.
Histology
Two types of cells form the epithelium of the processes ; one is an extension of
the gut epithelium, the other is a continuation of the epidermis. Because of the
origin of the processes, the former is found on the ventral surface of the processes,
the latter on the dorsal surface. The cells derived from the gut epithelium are
cuboidal to low columnar and are normally 8-10 /JL high; the nucleus is primarily
spherical, basal in position, vesicular and 3.5-5.0 ^ in size. The cells show a con-
spicuous "brush border" that, in the light of modern microscopy, is probably a
surface covered with microvilli. The position of the nucleus and the stratification
of the heterogeneous cytoplasm are evidence of a physiologically active cell. The
basement membrane of these cells is extremely delicate. The fact that mitotic figures
are seldom seen indicates that the processes probably grow at the base. The
epithelium derived from the epidermis is very thin, composed of flattened cells
normally arranged in an irregular double layer and often vacuolated. The transition
between the two types of cells is abrupt. The large cuboidal cells normally form
75% or more of the epithelial surface. The most typical appearance of the epi-
thelium occurs in embryos 10 mm. or less in length ; as time approaches for birth,
the epithelium and, indeed, the entire process undergo marked changes.
The medulla is formed of a mass of loose, spongy, connective tissue. Fibrocyte
nuclei are approximately 10 ^ in length, oval, pale, finely granular and homogeneous
in appearance. Approaching birth, many phagocytes appear in the tissues. As
is true for other goodeids, the blood supply to the processes is very rich, forming
an extensive capillary plexus on the medullary surface. The vascular character
is a property of the medulla, not of the epithelium. Occasionally, capillaries or
large vessels protrude beyond the surface of the entire process in the region of the
"epidermal" epithelium. The medullary connective tissue is continuous with the
submucosa of the gut and the sub-epidermal connective tissue of the body surface.
DISCUSSION
The present description of the ovary and the trophotaeniae of "Characodon"
ciscni differs from that given for Xcnotoca (variata} by Hubbs and Turner (1939)
in some respects ; there are two serious differences and other minor ones. In their
study, the median septum of Xenotoca is described as "entire, attached dorsally and
\cntrally, much folded" (Hubbs and Turner, 1939, Table II). This property places
Xcnotoca in the second phyletic line, along with Alloophorus and Chapalichthys.
However, in the present study only 12 of the 43 ovaries were found to follow this
description. An additional 13 ovaries had a septum essentially complete but with
minor or more serious variations, whereas 18 ovaries had a septum divided distinctly
into dorsal and ventral halves. In this species, therefore, the median septum is
inconsistent or variable in form and thus is an unreliable criterion for use in classi-
OVARY AND PROCESSES OF C. EISENI 313
fication. Using this criterion, "Characodon" eiseni may well be classified in three
phyletic lines, numbers 2, 6 or 7 (Hubbs and Turner, 1939, Table II).
No serious discrepancies were found in the description of the location of the
ovigerous tissue although it appears to the writer that, except for the extreme
anterior end, eggs seldom occur in the median septum ; they occur mostly in the walls
of the ovary and especially at the anterior end. This again differs somewhat from
the revision of Hubbs and Turner where Xenotoca is likened to Alloophorus and the
latter is described as having ovarian "walls . . . almost devoid of ovigerous tissue"
(p. 13).
Hubbs and Turner describe the trophotaeniae of Xenotoca as 6 to 8 in number,
very long and unsheathed (Plate II, Fig. 10). The processes are said to "arise by
dichotomous branching from three backwardly projecting trunks, one median and
two lateral" (p. 25). Having examined more than 200 specimens, the writer
concludes that there are four basic processes in "Characodon" eiseni, the one
posterior median process and two lateral processes as described by Hubbs and
Turner for Xenotoca but with an additional median process anterior to the anus.
The writer agrees with Turner that there is much secondary splitting (Turner,
1937). Furthermore, although the writer agrees that there may be as many as 6 to
8 processes, this is a number seldom attained ; 4 to 6 processes is a much more
representative number. The slight disagreement in number is a minor matter but
it is important that a fourth antero-median process be recognized as part of the
basic set of processes.
Another serious difference arises in the matter of the presence or absence of the
sheath around the process. Xenotoca is described as having unsheathed tropho-
taeniae (Turner, 1937; Hubbs and Turner, 1939), thereby placing it in a category
with Alloophorus robnstus, Chapalichthys encaustus, and Zoogoncticus cuitseoensis.
The size of the embryos, the stage of development and the number of specimens
examined may well affect the conclusions drawn. In embryos of "Characodon"
eiseni approaching birth, the processes do tend to show an absence of a sheath but
in younger stages there is no question of the presence of a sheath, although even
this is variable in degree of formation. Following Hubbs and Turner, the presence
of the sheath in the processes should place this species with genera such as Skiffia,
Ollentodon and Neotoca, in the subfamily Girardinichthyinae rather than in the
Goodeinae. The three genera listed are the only other ones in which the processes
are stated to be sheathed. While this paper is not intended to include an evolu-
tionary analysis of the species, it seems to the writer that the arrangement of
processes in "Characodon" eiseni could easily have arisen from the "trident"
arrangement present in species such as Neotocoa bilincata, simply by the addition of
a short median process anterior to the anus. Finally, a minor difference arises
in regard to the nature of the process epithelium. The writer is not in agreement
that the ". . . epithelium ... is everywhere simple and of irregular height"
(Hubbs and Turner, 1939, p. 25). In the younger embryos the epithelium has a
dual structure, depending on whether it is continuous with the epidermis or the
gut epithelium. The double nature is very clear ; each of the two types tends to be
quite regular in its own structure. The irregularity referred to may be true in
stages just before birth when the entire process undergoes marked changes,
preceding its resorption at about the time of birth. At this time the epithelium does
314 GUILI.KRMO MKXDOZA
become most irregular and is even sloughed off. The writer appreciates the fact
that this is a minor matter, a detail readily noticed in a descriptive, histological
study but likely to be missed in a paper of broader scope and concerned primarily
with overall taxonomic matters.
In conclusion, the writer points out the overall taxonomic impasse in which
these newer facts place "Characodon" eiseni. First, the description of the median
septum of the ovary is not in agreement with that given for Xenotoca variata by
Hubbs and Turner ( 1939). Second, because of the variability of the structure of the
median septum, "Characodon" eiseni can be placed in different phyletic lines within
the family as determined by the nature of the median septum. Hence this criterion
is unreliable for the classification of this species. Third, the sheathed processes
found in "Characodon" eiseni are totally different from the solid, non-sheathed
processes described for Xenotoca variata. Fourth, the presence of sheathed
processes in this species is inconsistent with the type of median septum described
here for "Characodon" eiseni or that of Xenotoca variata. In the classification
scheme devised by Hubbs and Turner, species that have sheathed processes have an
ovary with a thin, delicate, median septum and ovigerous tissue confined to two
dorso-lateral folds (e.g., Neotoca bilineata}. Such an ovary has but little in common
with that described for either "Characodon" eiseni or Xenotoca variata. Thus two
major criteria (ovarian structure and type of process) are at odds with each
other and one criterion (ovarian structure) fails to discriminate between two or
more phyletic lines.
The facts brought out in this paper raise the serious question whether taxonomic
criteria based on ovarian and trophotaenial structures can be used successfully
in the case of this species. At the same time, this paper does not propose to extend
this conclusion to the entire goodeid family since this study is limited only to one
species, "Characodon" eiseni. It may well be that a restudy should be made of the
degree of variation in the structure of the septum in some or most species of the
family, particularly those species in which the septum is ovigerous. It is not likely
that a median septum of the Neotoca bilineata type (thin and non-ovigerous) will
vary much. The criteria set up by Hubbs and Turner in 1939 no doubt will still
prove to be valuable, even though there may be exceptional forms such as this
species in which the criteria are not absolutely discriminatory. Lastly, a taxonomic
analysis of this species using other conventional criteria should help to clarify the
taxonomic relationships of "Characodon" eiseni and Xenotoca variata.
SUMMARY
The ovary and trophotaeniae of "Characodon" eiseni Rutter are described. The
median septum of the ovary is variable in structure ; the septum may be a single,
continuous sheet or it may be divided into dorsal and ventral halves. Ovigerous
tissue is confined primarily to the anterior region of the ovary but mostly to the
ovarian wall. There are four trophotaeniae (processes), two lateral and two
median, one anterior and one posterior to the anus. The processes are further
described as sheathed. The above facts are not in agreement with previously
published descriptions of Xenotoca variata with which this species has been synony-
mi/ed. The above facts are further contradictory with each other in assigning
OVARY AND PROCESSES OF C. EISENI 315
"Characodon" eiseni to a particular evolutionary line within the family Goodeidae.
The paper shows that the goodeid taxonomic criteria based on ovarian and tro-
photaenial structure are not discriminatory when applied to "Characodon" eiseni.
LITERATURE CITED
ALVAREZ, J., 1950. Claves para la determination de especies en los peces de las aguas
continentales Mexicanas. Sec. de Marina, Direction General de Pesca e Industrias
Conexas, pp. 1-136.
BUEN, F. de, 1942-1943. Los peces de agua dulce de la familia Goodeidae. Boletin Biol. Lab.
HUBBS, C. L., 1924. Studies of the fishes of the order Cyprinodontes. Parts I-IV. Misc. Publ.
Mus. Zool., Univ. Michigan, No. 13, pp. 1-31.
HUBBS, C. L., 1926. Studies of the fishes of the order Cyprinodontes. Part VI. Material for
a revision of the American Genera and Species. Misc. Publ. Mus. Zool., Univ.
Michigan, No. 16, pp. 1-87.
HUBBS, C. L., AND C. L. TURNER, 1939. Studies of the fishes of the order Cyprinodontes.
Part XVI. A revision of the Goodeidae. Misc. Publ. Mus. Zool., Univ. Michigan, No.
42, pp. 1-80.
JORDAN, D. S., 1923. A classification of fishes including families and genera as far as known.
Leland Stanford Jr. Univ. Publ., (Univ. Ser.}, 3: 77-243.
JORDAN, D. S., AND B. W. EVERMANN, 1896-1900. The fishes of North and Middle America.
Bull. U. S. Nat. Mus., 47 (4 parts), pp. 1-3313.
MEEK, S. E., 1902. A contribution to the ichthyology of Mexico. Field Columbian Mus. Publ.,
No. 65, Zool. Ser., 3: 63-128.
MEEK, S. E., 1904. The fresh-water fishes of Mexico north of the Isthmus of Tehuantepec.
Field Columbian Mus., Publ, No. 93, Zool. Ser., 5: 1-252.
MENDOZA, G., 1937. Structural and vascular changes accompanying the resorption of the
proctodaeal processes after birth in the embryos of the Goodeidae, a family of viviparous
fishes. /. Morph., 61 : 95-125.
MENDOZA, G., 1940. The reproductive cycle of the viviparous teleost, Neotoca bilineata, a
member of the family Goodeidae. II. The cyclic changes in the ovarian soma during
gestation. Biol. Bull, 78: 349-365.
MENDOZA, G., 1956. Adaptations during gestation in the viviparous cyprinodont teleost,
Hubbsina turneri. J. Morph., 99: 73-96.
REGAN, C. T., 1906-1908. Pisces. Biologia Centrali-Americana.
TURNER, C. L., 1933. Viviparity superimposed on ovoviviparity in the Goodeidae, a family of
cyprinodont teleost fishes of the Mexican Plateau. J. Morph., 55: 207-251.
TURNER, C. L., 1935. The use of the embryonic rectal processes of the embryos in a revision of
the classification of the family Goodeidae. Anat. Rec., 64 (Suppl.) : 137-138.
TURNER, C. L., 1937. The trophotaeniae of the Goodeidae, a family of viviparous cyprinodont
fishes. /. Morph., 61 : 495-523.
SYMBIOSIS OF HYDRA AND ALGAE.
II. EFFECTS OF LIMITED FOOD AND STARVATION ON GROWTH
OF SYMMIOTIC AND AFOSYMBIOTIC HYDRA
LEONARD MUSCATINE 1 AND HOWARD M. LENHOFF
/tit'ision tij Marine Hinlo</y, Scrimps Institution of Oceanography, University of California,
San Dicf/c. Culifiirnia, and Laboratory for Quantitative Biolouy,
University of Miami, Coral Gables, Florida
Very few measurements have been made on the effect of symbiotic algae
on growth of their various invertebrate hosts. Recently Karakashian (1963) dem-
onstrated that the algae symbiotic with Paramecium bursaria exert a strong
influence on the growth of the host. These studies were carried out with sym-
biotic and aposymbiotic individuals of known genetic and nutritional history
cultured in a defined medium. Culture techniques (Loomis, 1954; Muscatine and
Lenhoff, 1965) now permit a similar approach using green hydra, thus affording
insight into an association of algae and a metazoan. Previous studies on the role
of algae in green hydra (Goetsch, 1924; Haffner, 1925) were carried out in
undefined media, and lacked the quantitative precision necessary for critical
evaluation.
The present study describes experiments on the growth, survival, and protein
turnover of hydra with and without algae as a function of exogenous food supply.
Possible mechanisms of interaction between algae and host are discussed. A
preliminary note on some of this work has appeared elsewhere (Muscatine, 1961).
MATERIALS AND METHODS
All experiments were carried out with Chlorohydra I'iridissima, Carolina
strain 1960. The culture medium, and methods for maintaining animals in the
laboratory, sampling individuals for experiments, obtaining algae-free controls and
conducting growth experiments are described in a previous paper (Muscatine
and Lenhoff, 1965).
"Pale green" hydra containing known amounts of algae intermediate between
green and albino (== algae-free) were obtained in the following manner. Green
hydra were placed in culture solution containing 0.068 AI glycerine, which causes
the gradual elimination of algae (Whitney, 1907, 1908). At daily intervals for
eight days, groups of (en "uniform" (cf. Lenhoff and Bovaird, 1961) hydra were
removed, rinsed in clean culture solution, and exposed to C 14 O 2 for exactly 24
hours, using a procedure described by Muscatine and Lenhoff (1963). These
labeled animals were (hen rinsed in several changes of clean culture solution, and
placed on a Millipore filler (IIA-47) in a drop of deionix-.-d water. When relaxed,
the animals were flattened on (he filter by application of suction (cf. Lenhoff. 1959).
address : Department of Zoology, University of California, Los Angeles, California.
316
SYMBIOSIS OF HYDRA AND ALGAE. II.
317
The filter was dried, glued to an aluminum planchet and assayed for radioactivity.
The level of radioactivity of untreated green hydra controls was considered to
represent the net photosynthetic activity of the normal algal flora. Glycerine-
served as controls for animal fixation of C 14 O 2 . Figure 1 shows the radioactivity
of each group plotted against time grown in glycerinated culture solution. Hydra
sampled after four and six days of glycerine treatment were judged to contain,
240
-
GREEN CONTROL
200
X
t-
< i
-
100 *
<
X
o
o:
H
> 160
_
O
80 co
X
2
LJ
<
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H
X
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rn
^
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? 120
-
-
60 o
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-
-
40 >
(
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40
-
{
20
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ALBINO CONTROL V
<\$ i i
i i i i 9 o
12345678
DURATION OF EXPOSURE TO 0.068 M GLYCERINE (DAYS)
FIGURE 1. Radioactivity accumulated by green hydra exposed first to 0.068 M glycerine for
periods up to 8 days, and then to C 14 O 2 for 24 hours. Vertical bars denote twice the standard
deviation of the mean number of counts per minute. Non-glycerine-treated green controls, in
18 trials, gave 203.2 32.0 counts per minute per hydranth. Albinos gave less than two counts
per minute above background.
from this reference curve, approximately 10-20% and 4-6%, respectively, of their
usual normal complement of algae. These animals were washed with several
changes of clean culture solution one hour before experiments.
To graft the heads (hypostome and tentacles) of green hydra onto the bodies
(gastric region and below) of albinos, one-day starved stock hydra were bisected
transversely. Appropriate pieces were threaded on a hair and held together by
gentle pressure with watchmaker's forceps. Adhesion began within a minute or
two and grafts were available after 15-30 minutes. The approximate algal
content of green heads was estimated by first exposing whole intact "uniform"
green hydra to C 14 O 2 in a standard manner (Muscatine and Lenhofif, 1963), and
318
L. MUSCATINE AND H. M. LENHOFF
then cutting each animal in two just below the hypostome and tentacles. Each
head and body was then dried separately on a planchet and assayed for radio-
activity. In five replicates, green heads were found to contain 30.5 2.3% of
the normal complement of photosynthetically-active algae in an entire animal.
S 35 -labeled mouse liver (specific activity 1000-2500 counts per minute per
microgram protein nitrogen) was prepared, administered to hydra and fractionated
as described by Lenhorf (1961). Radioactive material was assayed, with cor-
rection for background, with an end window gas flow counter (Nuclear-Chicago
Clll-B).
80
t/j
x
Q.
40
cr
oJ
CD
(0)
(b)
(c)
DAYS
FIGURE 2. Semi-logarithmic plot of growth of green (closed circles) and albino (open
circles) C. viridissima (a) fed daily, (b) fed every second day, and (c) fed every third day.
Arrows indicate time of feeding.
RESULTS
1. The effect uj amount oj joud un yrou'th oj ijrccn and albino C. viridissima
In a previous paper (Muscatine and Lenhoff, 1965) we reported that green
and albino C. viridissima grew at nearly identical logarithmic rates when fed
daily on excess Artcmia nauplii. This is illustrated in Figure 2, curve a. A
doubling time of about 1.5 days is the maximum growth rate (k mn x) for this
species under these conditions (Muscatine and Lenhoff, 1965). Growth of
albinos at k max indicates that algae are not essential for logarithmic growth as
long as there is ample exogenous food. However, when food was limited,
growth rates of green hydra always exceeded those of algae-free individuals, as
shown in curves b and c. Curve b shows that the growth rate of green hydra
fed every second day deviated only slightly from the rate of animals fed daily.
Growth of albinos, on the other hand, lagged after the second feeding, and in-
creased only after a third feeding. Green hydra produced nearly twice the
SYMBIOSIS OF HYDRA AND ALGAE. II. 310
number of buds produced by albinos. When the diet of excess Artemia nauplii
was further limited to a feeding every third day (curve c), growth of green hydra
dropped off sharply during the first two-day interval without food, but resumed
a nearly normal rate immediately after the next feeding. Growth of albinos also
dropped off after two days without food but continued to lag through the second
feeding without resuming a normal rate. Again, green hydra produced almost
twice the number of buds produced by albinos.
Since hydra are normally given excess Artemia larvae at a feeding, there was
the possibility that in experiments with limited feeding, green hydra had simply
taken in more food. This was tested by feeding green and albino hydra daily
with single Artemia nauplii. This regime both controlled and limited the food
intake. Freshly hatched larvae were fed to individual green and albino hydra
with a tapered pipette allowing the larvae to leave singly. Since the number of
TABLE I
Growth of replicate cultures of green (G) and albino (A) C. viridissima fed daily but only
on single Artemia nauplii. Numbers in parentheses indicate total number
of shrimp given to each culture
No.
of hydranths on day
Exp.
i
2
3
4
5
6
7
k
(5)
(9)
(15)
(19)
(23)
(30)
G
10
17
22
30
41
60
71
0.277
G
10
18
25
31
41
57
71
0.277
1 A
10
20
23
25
30
35
36
0.121
A
10
17
19
22
27
37
39
0.187
(2)
(3)
(3)
(4)
(5)
(8)
G
4
7
8
10
13
21
0.346
G
4
5
8
9
11
17
0.277
G
4
6
8
9
11
17
0.277
A
4
5
6
6
9
11
0.198
A
4
6
6
7
7
12
0.210
A
4
5
6
7
10
12
0.231
hydranths in each culture changed as the experiment progressed, a second shrimp
was given to some individuals in order that cultures would receive the same
number of shrimp. In this case the additional larvae were fed to maturing buds.
Table I shows that under these conditions the average growth rate of green hydra
(0.29) still approached that of well-fed individuals, while the average for albinos
(0.19) was significantly lower (p < 0.05).
Some experiments were carried out to determine if a greater capacity for gastro-
dermal phagocytosis might have accounted for the increased growth of green
hydra on a limited food supply. Twelve green and 12 albino hydra were each
fed a small piece of S 35 -labeled mouse liver along with excess Artemia nauplii.
Fractionation by differential solubilities showed that 80% of the isotope was bound
in the alcohol, trichloroacetic acid-insoluble liver fraction, i.e., the residual protein
fraction, and was thus favorable for tracing the course of food protein from the
gut lumen into phogacytic digestive cells. At hourly intervals during the six
320
L. MUSCATINE AND II. M. LKNHOFF
hours following ingestion, duplicate pairs of green and albino hydra were bisected
longitudinally, and the gut contents (ingested but not phagocytized) were washed
out with culture solution onto a planchet. The radioactivity of this material was
then measured and compared to that remaining in the hydra tissues (phago-
100
80
CO
LU
00
CO
60
CO
40
20
o
o
_L
_L
34
HOURS
3. Rate of phagocytosis of S 35 -labeled mouse liver by replicate cultures of green
(closed circles) and albino (open circles) C. i-iridissiwa.
cytized). The curve in Figure 3 represents the rate of phagocytosis of sulfur-
labeled tissue. Phagocytosis proceeded relatively slowly over the first two hours,
more rapidly during the next two to three hours, and then more slowly after five to
six hours as the phagocytic capacity of gastrodermis reached a maximum. Both
green and albino hydra phagocyti/ed 85-95 9^ of the labeled tissue and at similar
SYMBIOSIS OF HYDRA AND ALGAE. II.
321
rates, indicating that the absence of algae did not impair the phagocytic capacity of
albino C. viridissima. Thus, the difference in growth of green and albino on a
limited food supply was not simply the result of a quantitative difference in food
intake. This conclusion is further borne out by starvation experiments.
2. The effect of starvation on survival of green and albino C. viridissima
Goetsch (1924) described an experiment in which green and albino hydra
were placed in the same aquarium with little food and the albinos gradually died
out. He concluded that albinos live only when well-supplied with food. These
observations were confirmed by randomly placing 10 green and 10 albino C.
viridissima in a 10-gallon aquarium containing aged tap water, several Gambusia
sp., common aquatic plants, and a sparse population of an unidentified ostracod.
This laboratory "ecosystem" was observed daily but otherwise unattended. After
three weeks the number of green hydra had at least trebled while no albinos
could be found.
TABLE II
Results of 8 replicate experiments showing Ike mean ( standard deviation of the mean)
number of green, pale green and albino C. viridissima surviving starvation,
and the range of survival times
No. of hydranths on day
Range of
Group
%
survival
algae
(days)
2
4
6
8
10
12
14
Green
100
10
20.51.5
24.7 1.5
28.5 1.9
29.5 4.3
29.0 2. 4
32. 5 0.7
31.00.0
28-30
Pale green
10-20
10
20.71.7
24.2 3.1
23. 7 3.4
23.43.7
23.0 3.6
21.04.9
22. 2 3. 2
24-26
Pale green
4-6
10
21. Oil.
25. 5 3.5
24.5 3. 5
24.5 3. 5
21.06.0
13.04.0
8.0 6.0
17-20
Albino
10
18.23.5
20.63.7
18.7 4.3
12.5 4.2
5.6 3.2
1.7
0.6
10-12
To obtain quantitative data on starvation, five green hydra were placed in
30 ml. of culture solution in a Petri dish (100 mm. X 15 mm.). Five albinos
were similarly treated. Also starved in the same manner were two different
groups of five "pale green" C. viridissima, one containing 4-6% and the other
10-20% of the normal algal flora. The animals were illuminated but not fed,
and the culture medium was changed once daily. The number of hydranths in each
vessel was recorded daily. The results are shown in Table II. During starvation
green hydra produced buds for 12 days and survived for nearly four weeks,
gradually becoming smaller during this time, and finally disintegrating. "Pale
green" individuals did not appear to change, judging from their relative shades
of green, until after about 10 days of starvation when the 5% "pale green" group
seemed noticeably whiter. Albinos produced buds for about 6 days and most
survived for only 10-12 days. One or two individuals, in subsequent starvation
experiments, survived for as long as 17 days. Unlike green and pale green
hydra, most of the albinos disintegrated soon after they discontinued budding.
This unusually premature event was characterized by crumbling of tentacles and
body tube until all that remained of each albino was an amorphous accumulation
of whitish debris. It was frequently difficult to decide when an albino w r as
"dead." This was arbitrarily taken as the time at which the crumbling of
322
L. MUSCATINE AM) II. M. I.KXHUKI<
tentacles \vas first noticed. Goetsch also observed the disintegration of starving
albinos in contrast to the gradual diminution of similarly treated green hydra.
From the data on starvation in Table II, it was possible to estimate the degree
to which the number of algae influenced survival. In Figure 4 the percentage of
algae contained initially by the hydra in each group is plotted against (1) the
average number of hydranths present at 12 days starvation, and (2) the range
of maximum survival times. In the first curve, 12 days was chosen because it repre-
sents the time at which no albinos remain, although data from 8-14 days give curves
of essentially the same character. The shape of the resulting curves is interpreted
to mean that survival ability of a starved C. viridissima is not appreciably impaired
20 40 60 80
% PHOTOSYNTHETICALLY-ACTIVE ALGAE
100
FIGURE 4. Survival of starved C. viridissima as a function of the number of algae contained.
Using data from Table III, the per cent of photosynthetically-active plant material is plotted
against the number of hydranths present after 12 days' starvation (open circles) and mean
survival (open squares).
until the level of its photosynthetically-active plant material drops below 15-20%
of its normal value. Thus, only about 5-10% of the normal algal flora appears
necessary for half-maximum survival ability of the starving host.
3. The effect of starvation on turnover of S 35 -Iabelcd food
To compare the turnover of protein by starving green and albino C. viridissima,
we measured the rate at which radioactivity was released into the medium by hydra
which had previously ingested S 35 -labeled mouse liver. Duplicate groups of 10
green, 20 albino, and 10 "pale green" (15% algae) hydra were fed sulfur-labeled
liver and allowed to regurgitate the uneaten portion 6 hours later. Immediately
after regurgitation 10 of the labeled albinos were decapitated and unlabeled green
heads of known algal content were grafted onto the labeled albino bodies as
SYMBIOSIS OF HYDRA AND ALGAE. II.
323
described under Methods. Each group of hydra (green, "pale green," albino, and
graft) was placed in 2 ml. of culture solution in depressions of plastic temperature
control blocks (Coral Research and Development, Miami, Fla.) maintained at
22.5 0.25 C. At 24-hour intervals for five days, the culture fluid was removed
from each group and the animals and vessels were rinsed with 0.5 ml. of culture
solution per group. The solution and rinsings were combined, dried on planchets
and assayed for radioactivity. A fresh 2-ml. portion of culture solution was added
to the hydra. After five days the animals were removed and assayed for radio-
activity. The sum of the radioactivity of fluid samples is the total S 35 present at
the beginning of the experiment. Material released is expressed as a per cent of
this total. In five experiments (Table III) the loss of S 35 by the groups of hydra
always bore the same relationship, although considerable variation was encoun-
tered from one experiment to another. Figure 5 shows the rates of loss in one
TABLE III
Per cent of 6' 36 lost by groups of green, albino, pale green (10-20% algae) and grafted
(30.5% algae) C. viridissima during 5 days' starvation
Expt.
Green
Albino
Pale
Graft
1 a
10.8
22.8
b
14.2
23.5
2 a
19.9
40.5
.
b
23.2
33.2
3 a
19.1
89.5
29.6
28.2
b
29.9
53.5
24.4
31.0
4 a
12.0
24.6
b
14.0
34.8
.
c
11.1
35.4
5 a
35.2
68.5
57.3
48.1
b
40.6
82.1
46.3
61.1
experiment. Invariably albinos lost material to the medium faster than any other
group. Pale green and grafted hydra which contained, respectively, 15% and 30%
of the normal complement of algae lost material at a lower rate. Green hydra lost
material at about half the rate of albinos and retained labeled material about twice as
long. The relationship between rate of loss of labeled material by a group of hydra
and its algal content is similar to that illustrated by the curves in Figure 4, where
relatively few algae have nearly the same effect on the host as does a full complement
of algae. The ability of the algae in grafted individuals to modify the rate of loss of
material from the labeled albino body, despite the localization of algae in the un-
labeled head, exemplifies a "replacement therapy" type of experiment, and suggests
that the algae in this case might act by releasing something which diffuses through
a distance.
That less material appeared in the medium of green and pale green hydra than
in the medium of albinos implied that the algae either (1) directly affected the
catabolic activities of the host cells, or (2) accumulated the labeled material after
it was released by the animal cells. This was investigated in preliminary experi-
ments in which sulfur-labeled hydra were starved for five days and then homogenized
324
L. MUSCATINE AND H. M. LENHOFF
by ultrasonic vibration. By gentle centrifugation most of the algae were separated
from the bulk of the animal tissues, but mutual contamination could not be avoided.
In two trials the resulting algal pellet contained 3.8% and 6.8% of the total radio-
activity in the entire homogenate, tentatively indicating that the algae did not
accumulate the isotope but depressed the rate of protein catabolism of the host.
DAYS
FIGURE 5. Rate of loss of S^-labeled material by green ( ), grafted ( (I ), pale green (O)
and albino (O) C. riridissima containing, respectively, 100%, 30%, 20% and 0% photo-
synthetically-active plant material.
DISCUSSION
The results of this study lead to the conclusion that symbiotic algae favorably
influence the growth, reproduction, survival, and protein turn-over of C. viridissiina.
The growth rate of green C. viridissiina on a limited food supply was consistently
greater than that of aposymbiotic controls (Fig. 2; Table I). This difference
was not the result of a proportionally larger food intake by green hydra (Fig. 3),
but of some intrinsic factor associated with the presence of algae, since even
during starvation green hydra produced more buds, survived longer, resisted
disintegration and displayed a lower turnover of sulfur-labeled protein compared
to aposymbiotic controls (Tables II, III). These results lend quantitative sup-
port to the observations of Goetsch (1924), who noted that (1) well-fed albino
hydra grew as well as well-fed green individuals, either in light or in darkness,
and (2) when starved in the light, green hydra survived for nearly twice as long
SYMBIOSIS OF HYDRA AND ALGAE. If. 325
as aposymbiotic controls. Partially "infected" hydra survived at least as long
as any of the aposymbiotic controls and appeared "less depressed." Goetsch
concluded that the algae were not essential when food was abundant but probably
played some role in augmenting survival when certain stresses, e.g., starvation,
were imposed on the host. Karakashian (1963) demonstrated a positive influence
of algae on growth of the ciliate protozoan, Paramecium bursaria, when bacterial
food was present in low concentration and when cultures were starved but
illuminated. A positive correlation of mean numbers of algae per paramecium
with growth rate and survival time was also observed. Our results thus
parallel these in several respects.
The adaptive value of symbiosis with algae is particularly evident from the
behavior of albinos in these experiments. Their low budding rate and tendency
to disintegrate early during starvation, and poor growth on a limited food
supply would be disadvantageous for survival in an environment where limited
food and periods of starvation are frequently encountered (Welch and Loomis,
1924). These observations perhaps explain why aposymbiotic adult C. viridis-
sima have not yet been found in natural waters, although algae-free eggs are often
produced by at least one strain of green and albino C. viridissima (unpublished
observations).
Possible mechanisms by which the algae influence growth of the host
1. Gas exchange and waste uptake
Geddes (1882) suggested that symbiotic algae augment the well-being of their
animal hosts in several ways, including (1) by taking up carbon dioxide and pro-
ducing oxygen during photosynthesis, thus facilitating host respiration, and (2)
by taking up host excretory wastes, such as ammonia, thereby creating a less toxic
micro-environmental milieu for the animal. These interactions undoubtedly take
place to some extent in most associations but as yet there is little direct evidence
that any of them are essential to the animal (see Droop, 1963). In fact, they ap-
pear to be non-essential for C. viridissima since individuals without algae grow at
kmax as long as they are well fed. Similarly, well-fed green and albino C. viridis-
sima grow at nearly identical rates in darkness where photosynthetic gas exchange
is again ruled out as an augmenting factor (Goetsch, 1924; our unpublished
observations).
2. Utilization of algal metabolic products
As suggested by Geddes (1882) and others (Keeble, 1908; Boschma, 1925;
Gohar, 1940, 1948) a host could benefit by digesting its symbiotic algae or utilizing
their extracellular products. On the basis of the observations in this study, little
can be said regarding digestion of algae by C. viridissima. Since there is no ap-
parent decrease in number of algae after two to three weeks' starvation, and since
10-20% of the normal flora can sustain the starving host, digestion of algae seems
unlikely but is not ruled out. As noted by Yonge (1944) symbiotic algae probably
resist digestion since the majority are found in animals which display intracellular
digestion.
326 L MUSCATIXK AND II. M. LENHOH
However, there is evidence that C. viridissima utilizes products of algal metabo-
lism. Experiments with C 14 O 2 show that 10-20% of the labeled carbon fixed by
the algae is transferred to the animal where some is incorporated into major
chemical fractions (nucleic acids, proteins, etc.). The specific activity of C 1 * in
algae-free green hydra tissues in these experiments was 50-100 times greater than
that in albino control tissues where some carbon was assimilated solely by hetero-
trophic fixation (Lenhoff and Zimmerman, 1959; Muscatine and Lenhoff, 1963).
Similar transfers take place in other coelenterate-algae associations (Muscatine and
Hand, 1959; Goreau and Goreau, 1960) and are implied to occur in others (Sar-
gent and Austin, 1949. 1954; Odum and Odum, 1955 ; Burkholder and Burkholder.
1960).
The results of this study and demonstration of the utilization of products of
algal metabolism by host cells lend support to the conclusion that the algae in C.
viridissima augment growth of the host by nutritional supplementation. Support
for this view comes also from the observation that adequate food can replace the
need for symbiotic algae (Goetsch, 1924; Fig. 2, this paper). A similar observa-
tion was reported by Parker (1926) and Karakashian (1963) for P. bursaria. The
inability of albino C. viridissima to withstand starvation and the tendency to disinte-
grate undoubtedly reflects a loss of function by this species. Neither green C.
viridissima nor the non-symbiotic species, H. littoralis, show this reaction to starva-
tion, which could be symptomatic of a nutrient deficiency, as a result of a metabolic
lesion. The growth lags and slow responses of albinos to intermittent feeding (Fig.
2) may represent the time needed to accumulate essential nutrients from the limited
food supply. In contrast, green hydra did not exhibit extended growth lags or
delayed responses to intermittent feeding. Auxiliary metabolites received from
the algae probably offset any deficiency, though only temporarily, since, as shown
in starvation experiments (Table II), the algae cannot sustain the animal indefi-
nitely without some exogenous food. Information on carbon turnover rates by
the algae, their extracellular products, the growth requirements of the host, and the
peculiarities of the metabolism of algae-free individuals should bring to light the
details of mechanisms of host-symbiont interaction in this association.
Part of this investigation was carried out at the Laboratories of Biochemistry,
Ho\\ard Hughes Medical Institute, Miami, Florida during the tenure of a Post-
doctoral Fellowship from the Division of General Medical Sciences, United States
Public Health Service (1963) to Leonard Muscatine, and an Investigator Award
of the Howard Hughes Medical Institute to Howard M. Lenhoff. We thank Mr.
I. Bovaird, Mr. Alfredo Lopez, and Mr. Enrique Nagid for technical assistance.
Slobodkin ( 1964) has recently demonstrated that the "ecological efficiency"
(yield energy /food energy) of experimental populations of C. viridissima is about
four times higher than that of Hydra littoralis (a non-symbiotic species), but only
in populations grown in the light. The implication is that photosynthetic carbon
is available to C. viridissima for energy. Slobodkin, L. B., 1964. Experimental
populations of Hydrida. /. Ecol. (Sup pi.} , 52 : 131-148.
SYMBIOSIS OF HYDRA AND ALGAE. 11. 327
SUMMARY
1. When fed daily on Artcmia nauplii, green and albino C. viridisshna grew at
nearly identical logarithmic rates. With limited food, growth of green hydra al-
ways exceeded that of albinos. This difference was not the result of a quantitative
difference in food intake.
in size. Albinos survived only 10-12 days, succumbing to starvation by relatively
sudden disintegration.
3. The relationship between survival ability and algal content was non-linear.
Animals with 20% of the normal flora survived nearly as well as those with a full
complement of algae.
4. Turnover rate of sulfur-labeled protein during starvation showed the rela-
tionship albino > pale green > green, among the groups tested. The presence of
symbiotic algae appears to depress the rate of protein catabolism.
5. It is concluded that symbiotic algae augment growth, budding, and survival
of C. viridisshna (Carolina strain 1960) by a mechanism which does not appear to
involve gas exchange or waste removal by the algae.
6. Evidence is presented in support of the hypothesis that algal metabolic prod-
ucts augment growth and survival of C. viridissima.
LITERATURE CITED
BOSCHMA, H., 1925. The nature of the association between Anthozoa and zooxanthellae. Proc.
BURKHOLDER, P., AND L. M. BuRKHOLDER, 1960. Photosynthesis in some alcyonacean corals.
Amcr. J. Bot. 47: 866-872.
DROOP, M., 1963. Algae and invertebrates in symbiosis. In: Symbiotic Associations. Soc. Gen.
Microbiol. Symp. no. 13. B. Mosse and P. Nutman, Eds. Cambridge, pp. 171-199.
GEDDES, P., 1882. The yellow cells of radiolarians and coelenterates. Proc. Roy. Soc. Edin-
burgh, 11: 377-396.
GOETSCH, W., 1924. Die Symbiose der Susswasser-Hydroiden und ihre kiinstliche Beeinflussung.
Zcitschr. Morph. Okol. Tiere, 1: 660-731.
GOHAR, H. A. F., 1940. Studies on the Xeniidae of the Red Sea. Publ. Mar. Biol. Sta.
Ghardaqa, 2: 25-118.
GOHAR, H. A. F., 1948. A description of some biological studies of a new alcyonarian species
Clariilaria hamra Gohar. Pub. Mar. Biol. Sta. Ghardaqa, 6: 1-33.
GOREAU, T. F., AND N. I. GOREAU, 1960. Distribution of labeled carbon in reef -building corals
with and without zooxanthellae. Science, 131: 668-669.
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328 L. MUSCAT1NE AND II. M. LENHOFK
MUSCATINE, L., 1961. Symbiosis in marine and fresh water coelenterates. In: The Biology of
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THE DEVELOPMENT OF EGGS OF THE SCREW-WORM FLY
COCHLIOMYIA HOMINIVORAX (COOUEREL) (DIPTERA:
CALLIPHORIDAE) TO THE BLASTODERM STAGE
AS SEEN IN WHOLE-MOUNT PREPARATIONS
JOHN G. RIEMANN 1
Entomology Research Division, Agric. Res. Serr., USD A, Mission, Texas
In studying effects of radiation or chemical mutagens on insect germ cells, being
able to examine the chromosomes of nuclei in freshly deposited eggs would provide
many advantages. Meiotic division of the oocytes typically occurs after the eggs
are deposited. Thus, both the meiotic nuclei and the mitotic ones of the cleavages
or later stage divisions could be studied. In addition, only in freshly laid eggs can
the chromosomes of sperm be directly examined after treatment that produces domi-
nant lethal mutations. In spite of these advantages, only a few such studies have
been made of the nuclei of very young eggs, to ascertain the presence of chromo-
somal aberrations or abnormal nuclear divisions and death (i.e., Sonnenblick, 1940,
on Drosophila; Whiting, 1945a, 1945b, von Borstel, 1955, on Habrobracon).
Neglect of this kind of study has probably been due in part to technical difficulties
in collecting and preparing enough eggs at the exact stage of development required.
In addition, nuclei and chromosomes of such eggs, as a rule, are very small and
thus difficult to study.
Recently the author and his associates became interested in determining whether
chromosome aberrations induced in the sperm or oocytes of screw-worms, Cochli-
omyia hominh'ora.r (Coquerel), could be studied in the young egg, in at least a
reasonably satisfactory manner. Sectioned material was quickly found unsatisfac-
tory for this purpose and emphasis was placed on whole-mount preparations.
Normal development to the stage of blastoderm formation, as followed in the whole-
mounts, is described herein. Chromosome aberrations actually found in young
eggs after treatment of screw-worm flies with gamma radiation and the alkylating
agent, tretamine, w r ere discussed in an earlier paper (LaChance and Riemann,
1964).
MATERIALS AND METHODS
The sexually mature females of the Florida Normal strain used in this study
usually oviposit readily when offered warm lean meat. Each female will then nor-
mally produce 200-300 eggs within a period of 15-20 minutes. These eggs, ce-
mented together in a compact mass, are each about 0.7 mm. long and no wider than
0.16 mm. Each one is covered with a rather thick chorion which must be removed
in making a whole-mount preparation.
Division, State University Station, Fargo, North Dakota 58103.
329
330 JOHN (-. K I KM ANN
To obtain eggs of a fairly uniform age, individual flies were allowed to oviposit
for one minute in shell vials placed in a water bath heated to 35 C. The flies were
then discarded and the vials with the deposited eggs, usually 10 to 20 in number,
were removed from the water bath and held at room temperature (24-26 C.) until
fixation.
The whole-mount procedure was essentially that described by von Borstel and
Linclsley (1959) in their modification of the technique developed by Schmuck and
Metz (1931). First, the eggs were dechorionated by shaking them gently in \%
sodium hypochlorite (commercial bleach diluted 1:5 in distilled water) for not more
than two minutes. By the end of this period most eggs had lost their chorions.
The eggs were removed from the hypochlorite solution by straining them through
a cloth. They were then washed briefly in distilled water and placed in rows on
22-mm. coverslips by means of an artist's brush. Each egg was then gently punc-
tured (usually at the posterior or blunt end) with a fine needle so that a thin
stream of ooplasm flowed onto the surface of the coverslip. This puncturing was
essential for good fixation and the extruded ooplasm served to attach the eggs firmly
to the coverslips. As soon as possible after puncturing, the coverslip with its at-
tached eggs was placed in Kahle's fixative. All fluids used in preparing the eggs
were kept at room temperature.
It took about 4-5 minutes to handle 10-15 eggs, from the begintning of dechori-
onation to placing the eggs in the fixative. Fewer eggs could be handled somewhat
faster. In general, different groups of eggs fixed at comparable times after depo-
sition were quite similar in stage of development. Also, puncturing one end of the
egg or the other, or even allowing the nuclei to flow out of the egg, made little
difference in the timing of the stages of development, since fixation occurred rapidly.
After fixation, the eggs were stained according to the Feulgen procedure with
Schiff's solution, as outlined by von Borstel and Lindsley. Because of the eggs'
rather considerable thickness, the stained and dehydrated specimens were usually
mounted on another coverslip instead of on a slide. In this way the mounts could
be easily turned over to permit examination of both sides under high magnification.
Generally the preparations were allowed to clear for a few days in the mounting
medium (Diaphane) before they were examined. This was particularly desirable
for examining cleavage nuclei. An optical system that produced little contrast was
also found to be highly desirable for examining eggs.
More than 600 eggs were examined in preparing this description of egg develop-
ment in the screw-worm. Two series of eggs fixed at 15-minute intervals through
the first two hours of development and one series fixed at 5-minute intervals from
the first to the third hour were prepared. Also prepared were numerous other
series of eggs less than one hour old, particularly less than 25 minutes old, since
this time interval covered the most significant periods in determining the effects of
mutagens on germ cells.
All drawings were made with a camera lucida. However, to save space, some
nuclei were drawn somewhat closer together than they would have appeared in true
scale.
OBSERVATIONS AND DISCUSSIONS
LaChance and Leverich (1962) demonstrated that the meiotic nuclei of screw-
worm eggs go through prophase I and metaphase I while the eggs are still in the
EARLY DEVELOPMENT OF SCREW-WORM FLY 331
ovaries. By the time the eggs have reached maturity in the 5-day-old females, the
oocytes are in early anaphase I, in which stage they remain until the eggs are actu-
ally deposited. The chromosomes (six pairs) of these anaphase nuclei are much
contracted, and each meiotic figure appears to be merely a single, very small chro-
inatin mass in which some of the homologous chromosomes probably remain in con-
tact with each other. Each nucleus is located in the superficial ooplasm at a point
on the dorsal surface of the egg about one-fifth of the total egg length from the
anterior end.
In a few eggs, fixed individually as early as three minutes after deposition, the
nuclei were still in the condensed early anaphase characteristic of the mature ovarian
eggs. Nuclei 1-2 minutes older had longer chromosomes and were usually in late
anaphase or telophase I (Fig. 1). After telophase I, the egg nuclei went at once,
without any interphase stage, through the second meiotic division, which was com-
pleted in 7-8 minutes. At the end of telophase II (Fig. 2), all egg nuclei had
formed a straight line that extended from the site of the original anaphase I nucleus
to a point somewhat further into the interior of the egg but still near the surface.
The position of the line of nuclei (and hence the division plane at anaphase I) with
regard to the long axis of the eggs varied widely from egg to egg. In some eggs
it extended posteriorly, in others anteriorly, and in still others in various inter-
mediate positions, although always with one end located further in the ooplasm than
the other.
The chromosomes of the meiotic nuclei were extremely small and as a rule indi
vidual ones could not be recognized, even in the anaphase figures where they were
usually fairly well separated.
Immediately after completion of the second division, the terminal nucleus (the
one farthest inside the egg) swings out of line and moves as the female pronucleus
to a central position in the egg interior at about the same level on the long axis of
the egg as the original oocyte. As the female pronucleus moves, it is transformed
into an interphase nucleus surrounded by a membrane. The other three meiotic
nuclei remain in their original positions as the polar bodies. However, they quickly
follow the pronucleus into interphase. This transition starts in the other terminal
nucleus a little before it does in the two medial ones.
During the period when the meiotic divisions are taking place, the heads of such
sperm as may be present (from 1-5), are seen as short Feulgen-positive rods (Figs.
1 and 2), usually located in the deeper ooplasm of the same general level as the
oocyte nuclei. Occasionally a more elongate, threadlike sperm head, such as normal
motile sperm possess, was noted, but usually only the short rods were seen, even
in the youngest eggs. Sperm tails were presumably present in the eggs but they
did not stain and could not be detected.
In near synchrony with the oocyte nuclei, all sperm heads in an egg were trans-
formed into interphase nuclei. One of these nuclei moved to a position immediately
adjacent to the female pronucleus to become the male pronucleus. Thus, by the
end of about 9 minutes, only interphase nuclei were present in the eggs. When first
formed, these nuclei have a diameter of about 5^ microns which increases to 12 mi-
crons. Presumably during this 9-minute period cell synthesis takes place, involving
among other things DNA replication.
By the end of about 12 minutes, all nuclei, including the polar bodies and any
332
JOHN' G. R1F.MANN
extra sperm nuclei that might he present, have entered into early prophase (Fig. 3).
By 1415 minutes they have usually reached metaphase with the two pronuclei
being included in a single unit to complete syngamy. The first cleavage division
(Fig. 4) quickly follows and succeeding cleavages occur in rapid succession (Fig.
t
\
2
s
s \
\ .
PN
3
FIGURE 1. Four-5-minute egg, telophase I.
FIGURE 2. Seven-8-minute egg, telophase II.
FIGURE 3. Eleven-12-minute egg, late prophase before syngamy.
had disappeared from one of the pronuclei.
The nuclear memhrane
5). Approximately 5 minutes separate the first few cleavages, but the others occur
somewhat less rapidly. By the end of one hour the eighth and final internal cleavage
division is usually in progress. Thus, at 25-26 C. cleavage within the interior of
the egg occupies a period of about 45 minutes, with the average division cycle lasting
only about (> minutes. This rate is somewhat faster than the cleavage cycle of about
9-10 minutes at 20-30 C. reported for Drosofihila (Sonnenblick, 1950) and 10
KARLY DKYKLOPMKNT OF SCRKW-WORM FLY
333
minutes at 20 C. for Calliphora t'icina (R. and D. ) [erythrocephala >
( A[elander, 1'tfo) and may represent the most rapid rate of mitosis reported for
multicellular animals ( Mazia, 19(>1 ), although it would seem rather
other higher Diptera develop as rapidly.
PB
CN
I
4
PB
FIGURE 4. Fifteen-16-minute egg, first cleavage telophase.
FIGURE 5. Thirty-31 -minute egg, fourth cleavage metaphase.
Observing cleavage nuclei was rather less satisfactory than observing meiotic
ones. In part, the difference was due to the obstruction caused by the overlying
ooplasm even after it had cleared, but in addition the cleavage nuclei appeared to
stain less deeply. Again, individual chromosomes could not lie distinguished as a
i . i||\ G. l< I KM ANN
ruli 1 . Sometimes male and femaU chromosome complements remained somewhat
separated during the first cle; '.sion, hut more usually they could not be
recogni/ed after the\ had. , , the first metaphase figure. Viewing cleavage
divisions \vas made easier 1>\ fact that they all occurred in a plane rather closeK
parallel to the egg surface.
The first cleavage ' .;. nail] in the area in which svngamv occurs. \\"itlt
repeated divisions there is a -.pread of nuclei, and hv the end ot the eighth division
they are rather evenly ited along the length of the egg.
The somewhat slo ; \elocity of the later internal cleavages appeared to he
associated with a ch ' in duration of the different stages of cell division. Very
careful timing was rei|iiircd to obtain metaphase. anaphase, or telophase figures
(hiring the first 2 3 cleavage divisions. On the other hand these stages were found
more often than interphases or prophases in eggs fixed at various later times. All
the first S cleavages are probably completely synchronous in the intact egg, but in
the usual stained specimen a slight gradient ot development awav from the site of
puncturing was noted.
After the end of the eighth cleavage division in the interior of the egg, most
nuclei have migrated near the surface of the egg to form the incipient blastoderm or
blastema by the end of 1 hour and 10 minutes. After the blastema is first formed,
four other cleavage divisions of most of the nuclei occur. The first of these divi-
sions takes place shortly alter the nuclei complete their movement to the egg sur-
face. The last division is usually underwav or completed by the end of the second
hour. This cycle, lasting about 15 minutes, compares rather closely with the 17-
minute cycle that Agrell (1963) and Melander (19()3) reported for the same four
di\i.xions in ('. rvV/m/. After the 12th division a prolonged interphase takes place.
at the end of which further divisions occur. During the long interphase period,
cell membranes are formed around the nuclei located in the surface ooplasm. to be-
come the definitive blastoderm.
These last four cleavages are not completely synchronous like the first S, but
instead appear to follow the pattern reported by Agrell ( 1<>(>3) for ('. t'icina. For
the hrst three divisions there was a rather slight mitotic gradient from the anterior
end of the egg. and also during the llth division some nuclei near the posterior end
were observed to divide earlier than those more anterior. During the 12th division
a definite mitotic gradient proceeding from both ends of the egg was noted (Fig. 6).
Xot all ol the earlv cleavage nuclei migrate to the surface ooplasm to form the
blastema. Some remain behind as the so-called yolk nuclei or vitellophags. These
divide out of synchrony with the blastema nuclei, to form rather massive clusters of
nuclei ( Fig. 7 \ by the time the 12th division is completed. No evidence was seen
to indicate that anv ot the blastema nuclei migrate inward to increase the' number of
yolk nuclei.
Shortly before the 10th cleavage a cluster of nuclei appear outside of the blas-
at the posterior end of the egg. These are the .so-called pole cells which pre-
here as in other species, include' the primordial germ cells. In ('. t'iciini
i actually only nuclei ) are also set off at about the time of the 10th divi-
''. according to Soiineublick (1950), the first ones appear at the time
vision in l^rosopliilti. Xo divisions were detected among the pole cell
nuclei dii ii riods when the later cleavages occurred.
EARLY DEVELOPMENT OF SCREW-WORM
Melander (1963) described in great detail how the "pseudo-chiasmi ,ied
during the 9-1 3th nuclear divisions in C. I'icina, result in chromosome diminution
by causing the loss of small chromosome fragments. No attempt was made, to
study possible chrosome diminution in the screw-worm. However, in tli< bl
PC
t
~* . Jt*
FIGURE 6. One hour and 59-60-minute egg. The nuclei at either end have gone into
interphase while those in the central region are still dividing; 400 X.
FIGURE 7. Two hour and 15-16-minute egg, showing the clumped yolk cells and the
interphase nuclei of the blastema after the completion of the 12th division; 320 X.
Explanation of captions: C N, cleavage nuclei; P B, polar bodies; PC, pole cells; P N,
pronucleus ; S, sperm cell ; Y, yolk cells.
many anaphases exhibited configurations that appeared to be similar to the pseudo-
chiasmata described by Melander. Thus, it seems probable that the events in the
two species are at least somewhat similar.
As stated earlier, the polar bodies and surplus sperm nuclei of screw-worm egg>
go into metaphase at the same time as the pronuclei and remain in this stage until
they eventually disappear. The sperm nuclei can be seen during early cleavages
336
[OHN (.. RIEMANN
I \BU I
1 iif seuuen<f in tiif develop ..v-7ew/ eggs through blastoderm jonnution*
Minutt
i) 1
l (,
5-8
8 l '
I. 1 I
14-16
29 SI
Minutes
Sperm mo\e into are 44-46
which remains in e.irh meiotic
anaph.ise I. 59-61
Meiotic division 1 is completed.
Meiotic division li i- c ompleted. 74-76
All nuclei go into interphasu. 1'ro-
nnclei move l< adjacent position in ')(! ( > 1
tin- interior of the egg.
All nuclei pass synchronously into 104-106
metaphase. Syngamy occurs as 120-122
the two pronuclei form a single 150
figure.
( 't 'inplel ii ni o| clea\ age I .
Cleavage 1 1 1 in progress or completed,
4-8 nuclei.
Stage "I <lr\rlo|,iiirnt
Cleavage V completed and division
\ I may lie in progress; S2 nuclei.
Cleavage \ III generally in progress;
1 28 dividing nuclei.
Blastema formed with division IX
usually in progress.
Division X in progress. I'ole cell
nuclei set aside.
Division XI usually in progress.
I >ivision XII usually in progress.
Cell membranes around surface nuclei.
definitive blastoderm.
* Oviposition .ii S5 ('., development after one minute at 24-26 C.
but not during tin- later om-s. The polar bodies remain until the blastema is formed
but then quicklv undergo dissolution. Very rarely we observed one of the haploid
polar bodies dividing at the same time as the first cleavage nucleus.
1. /'olys/n'riny in screw-worm c;/(/s
It has lon^- been considered a general rule that in insects each egg is penetrated
by several sperm ( \Yigglesvvorth, 1950). However, Hildreth and Lucchesi (1963)
tound that, contrary to the observations of earlier workers, the eggs of Drosophila
melanogaster and /). I'irilis usually recei\'ed only a single sperm. As a result of
their studies, they raised the question as to how common polyspermy might actually
be in insects.
Many screw-worm eggs contained only a .single sperm, but more often than not
they had two or more sperm. In no egg, however, were more than 5 sperm found
and this number was quite unusual. Also, an inseminated fly often deposited a few
eggs that had not been fertilized. The presence of these unfertilized eggs probably
explains why somewhat les, than 100'; of the eggs from normally inseminated fe-
males usuall hatch.
TABLE II
Distribution annul in u MI in file of
I nlerlili/cd eggs
Eggs containing one sperm
Kggs i ontaining two sperm
Kggs ( ontaining three sperm
I '. CO ling lour sperm
Potal numl >l vgs
Total number of sperm
e]
2
30
39
1 I
.1
88
L62
EARLY DEVELOPMKXT OF SCREW-WORM FLY
337
The distribution of sperm in 88 eggs from 10 different females is shown in Table
II. All of these eggs were fixed before they were 8 minutes old, when the rodlike
sperm heads are relatively easy to count.
Occasionally a sperm nucleus was observed very near one of the polar bodies
although in no instance had a second zygote actually been formed. However, the
appearance of an occasional gynandromorph probably indicates that a second zygote
is sometimes formed.
3. Development of unfertilised eggs
Virgin screw-\vorm females oviposit nearly as readily as inseminated ones, but
their eggs apparently never hatch. However, young eggs in which no sperm could
be detected often completed both meiotic divisions. To determine how far develop-
ment advances in unfertilized eggs, whole-mounts of 8-20 eggs were prepared from
each of 15 virgin flies. One portion of the eggs were fixed at 5^-7 minutes after
TABLE III
'L 'he development of eggs from virgin females
Age at fixation
5J-7 min.
14-16 min.
1 i-2 hrs.
No. of females
5
6
4
No. of eggs
53
72
60
Aborted meiotic division I
12
Meiotic division I completed or in progress
19
Meiotic division II completed or in progress
22
Pronucleus not formed or did not migrate to interior of^egg
35
33
Normal migration of pronucleus
33
24
Cleavage I completed or in progress
4
3
Cleavage II completed or in progress
deposition, another portion at 14-16 minutes, and a third at \\-2 hours. To elimi-
nate any possibility that dechorionation and other steps involved in the handling of
the eggs might initiate development, these operations were limited to not more than
5 minutes immediately prior to fixation.
Results of observations on the stained preparations are shown in Table III.
They demonstrate that fertilization is not strictly necessary for initiation of develop-
ment. However, it is also evident that the presence of sperm in the eggs has some
influence even on meiotic divisions, for nearly one-third of the nuclei fixed at 5^-7
minutes had failed to complete the first division. It was also obvious that some of
the other nuclei could not have gone through the second division. Even in eggs in
which the two divisions were completed, the pronuclei had often failed to migrate
into the interior of the egg. Thus, in over half the eggs fixed at 14 minutes or later,
clumps of chromatin were found only at the site normally occupied by the three
polar bodies. In some eggs, each of these clumps was observed to be composed of
four smaller clumps representing all of the meiotic nuclei. Observations on other
unfertilized eggs fixed at 8-9 minutes demonstrated that when meiosis was com-
338 JOHN G. RIEMANN
pleted, the oocyte nuclei went through the usual interphase stage before returning
to metaphase.
Scoring of the older unfertilized eggs was easier because development always
stopped at a stage at which all nuclei were in metaphase. Apparently no nuclei had
disappeared by the time the oldest preparations were fixed.
The author wishes to express his appreciation to Dr. Leo LaChance, who sug-
gested this study and helped in many ways during its progress. He also wishes to
thank Miss Ann Leverich and Miss Sarah Bruns for their technical assistance.
SUMMARY
1. Development of screw-worm eggs from the first meiotic division to blasto-
derm formation was studied from whole-mount preparations. Both meiotic divi-
sions were completed by 7-8 minutes. Syngamy at 1415 minutes was quickly
followed by the first cleavage division. The first 8 cleavages took place within the
interior of the eggs, and the last of these occurred approximately one hour after egg
deposition. After the 8th division, most cleavage nuclei moved near the egg sur-
face to form the blastema by the end of about 1 hour and 10 minutes. This move-
ment was followed by four more divisions of the blastema nuclei. The last of these
divisions was underway, or had been completed, by the end of the second hour.
There was then a prolonged interphase period, during which cell membranes formed
around the blastema nuclei to become the definitive blastoderm.
2. The first 8 cleavages were synchronous, but for the last four divisions an
anterior-posterior gradient was evident. During the llth division, and especially
during the 12th division, there was also an accompanying mitotic gradient proceed-
ing from the posterior end of the egg.
3. After the 8th cleavage some nuclei remained behind to form the yolk nuclei
or vitellophags. Also, the pole cells were set aside after the 9th division but prior
to the 10th.
4. A low order of polyspermy was found in most eggs, but many of them re-
ceived only a single sperm. Most unfertilized eggs completed at least the first
meiotic division, but very few of them achieved the first cleavage division and none
developed further than this stage.
LITERATURE CITED
AC-.KELL, IVAR, 1963. Mitotic gradients in the early insect embryo. Arkiv. Zool, 15: 143-148.
HILDRETH, P. E., AND J. C. LuccHESi, 1963. Fertilization in DrosnphiJa. Dcrcl. BioL, 6:
262-278.
LACHANCE, L. E., AND A. P. LEVERICH, 1962. Radiosensilivity of developing reproductive cells
in female CocliUoinyia hominivorax. Genetics, 47: 721-735.
LACHANCE, L. E., AND J. G. RIEMANN, 1964. Cytogenetic investigations on radiation and
chemically induced dominant lethal mutations in oocytes and sperm of the screw-worm
fly. Mutation Res., 1: 318-333.
MAZIA, DANIEL, 1961. Mitosis and the physiology of cell division. In: The Cell, Vol. Ill, pp.
77-440. Edited by J. Brachet and A. E. Mirsky. Academic Press, New York and
London.
MELANDER, YNGVE, 1963. Chromatid tension and fragmentation during the development of
Calliphora crythroccphala Mcig. (Diptera). Ilercditas, 49: 91-106.
EARLY DEVELOPMENT OF SCREW-WORM FLY 339
SCHMUCK, M. L., AND C. W. METZ, 1931. A method for the study of chromosomes in entire
insect eggs. Science, 74: 600-601.
SONNENBLICK, B. P., 1940. Cytology and development of the embryos of X-rayed adult
Drosophila mclanogastcr. Proc. Nat. Acad. Sci., 26: 373-381.
SONNENBLICK, B. P., 1950. The early embryology of Drosophila mclanogaster. In: Biology of
Drosophila, Chapter 2, pp. 62-167. Edited by M. Demerec. John Wiley and Sons,
New York.
VON BORSTEL, R. C., 1955. Differential response of meiotic stages in Habrobracon eggs to
nitrogen mustard. Genetics, 40: 107-116.
VON BORSTEL, R. C., AND D. L. LINDSLEY, 1959. Insect embryo techniques. Stain Tech.. 34:
23-26.
WHITING, A. R., 1945a. Effects of X-rays on hatchability and on chromosomes of Habrobracon
eggs treated in first meiotic prophase and metaphase. Amcr. Naturalist, 79: 193-227.
WHITING, A. R., 1945b. Dominant lethality and correlated chromosome effects in Habrobracon
eggs X-rayed in diplotene and in late metaphase I. Biol. Bull., 89: 61-71.
WIGGLESWORTH, V. B., 1950. The Principles of Insect Physiology. Fourth ed. Dutton, New
York.
THE RELATIONSHIP OF SALINITY TO LARVAL SURVIVAL
AND DEVELOPMENT IN NASSARIUS
OBSOLETUS (GASTROPODA) 1 - 2
RUDOLF S. SCHELTEMA
Woniis Unit- OiV(/;i</</n//>/nV Institution, Woods Hole, Massachusetts 0-543
Not until recently has the relationship of salinity to the survival and develop-
ment of marine larvae been seriously examined through laboratory observations.
The earliest studies upon mollusks were confined almost exclusively to the em-
bryonic and very early shelled pelagic stages of pelecypods. Thus, Seno, Hori
and Kusakabe (1926), Amemiya (1926), and Rao (1951) determined the effect
of reduced salinities upon the early development of, respectively : Ostrea gigas and
Crassostrca virginica: Ostrea angulata and Ostrea cdulis ; and Ostrea madrasensis.
Because the early larvae of Crassostrca virginica survived salinities far lower than
those found in the habitat of the adult, Clark (1935) concluded that the effect of
salinity was unimportant in determining the mortality of oyster spat in Malpeque
Bay, P.E.I., Canada. Turner and George (1955) showed experimentally that the
larvae of Venus mercenaria would not swim past a salinity discontinuity of 20 and
15 parts per thousand (%c~). The very interesting results of Haskin ( 1964)
reveal a direct relationship between salinity and swimming activity of oyster
larvae (Crassostrca virginica}. Haskin also demonstrated that light intensity
and its spectral composition modify the response elicited from late "eyed" oyster
larvae. Wells (1961) has compared the "salinity death points" of the adults and
early larvae of two species of gastropods, TJiais floridana and Cerithium floridanuui.
In the former, little difference between the "salinity death point" of the adult
and larva was found, whereas in the latter species the "salinity death point" of the
larva was at a higher salinity than of the adult. Not until the investigations of
Davis (1958) upon Crassostrea virginica and Venus mercenaria and of Davis and
Ansell (1962) on Ostrea edit I is have observations on the effect of salinity over the
entire pelagic period of larval molluscan development been made. Stickney (1964)
in addition has recently cultured Mya arenaria larvae and noted their response to
salinity. No laboratory experiments on the relationship between salinity and
growth in estuarine prosobranch gastropod veliger larvae have been published.
Field studies on the effect of salinity upon survival and development of larval
mollusks deal largely with commercially important species (Nelson and Perkins,
1930; Carriker, 1951; Korringa, 1952; Kunkle, 1957; Haskin, 1964; etc.) and no
attempt to summarize this work is made here.
1 Contribution No. 1621 from the Woods Hole Oceanographic Institution, Woods Hole.
Massachusetts.
2 This research was supported in part by grants 17883 and GB-2207 from the National
Science Foundation. I wish to thank my assistant. Mr. (Jonlon Enk, for his help during the
conduct of sonic of the experiments described here.
340
RELATIONSHIP OF SALINITY TO LARVAL SURVIVAL 341
A common species which inhabits the intertidal flats of estuaries along the east
coast of North America from Chaleur Bay in the Gulf of St. Lawrence to northern
Florida is the mud snail or basket shell, Nassarius obsoletus Say. The ecology,
certain aspects of which have recently been reviewed (Scheltema, 1964), is rather
well known and the pelagic larval development and early post-larval life history have
been described (Scheltema, 1962a). The lower limits of salinity at which the
adults of N. obsoletus are naturally found range between 15/cc and 20%o.
reported on the effect of salinity upon survival and growth of the veliger larvae.
I report here upon the results of some experiments with the larvae of N. obsoletus
which (1 ) demonstrate the low r er limit at which salinity becomes lethal to both
the larvae and adults, and (2) show the effect of reduced salinity on growth be-
tween the time of emergence from the egg capsule to the completion of larval
development.
EXPERIMENTS ON THE LOWER LETHAL SALINITY FOR NASSARIUS OKSOLETUS
The lethal salinity for a species may be determined either experimentally in the
laboratory or from observations in the field. In the laboratory, organisms may be
subjected to different salinities and their behavioral or physiological responses
measured (e.g., Blum, 1922), while in the field unusual natural conditons, such
as sudden changes in runoff, may, by large mortalities, show when salinity limits
tolerated by a particular species have been surpassed (e.g., Beaven, 1946).
A criterion to be used in the laboratory by which the effect of salinity upon an
organism may be quantitatively measured is difficult to find. The methods adopted
here were unsophisticated, but the results were reasonably reproducible.
Salinity lethal to adult snails of N. obsoletus was determined by placing either
15 or 20 organisms from a collection made on the intertidal flats in one of a series
of four-liter tanks. Salinities in the series systematically descended in value from
full-strength sea water to about 5% . Reduced salinities were obtained by diluting
sea water with tap water. The resulting salinity in each tank \vas checked w r ith
a hydrometer. The interval between tanks in the initial experiments was 5%o. In
subsequent experiments this was reduced to 2%c as values approached the lethal
limit of the organisms. All the experiments were performed at room temperature
(ca. 20 C.). The animals were collected from a brackish- water estuary near the
laboratory and held overnight at a salinity of lS%c before use. At the beginning of
the experiment the snails were directly transferred to the salinity being tested.
The effect of salinity was appraised by watching the behavior of the snails. Snails
completely withdrawn into the shell were considered "inactive," whereas those not
completely withdrawn were regarded as "active." At each observation the per-
centage of active and inactive snails was recorded.
The results of these simple experiments are shown in Figure 1. The graph
illustrates that the region of stress lay between \2.S%o and 13.5% salinity. The
results are after four hours, but when the experiments were extended over a period
of three days the values do not differ significantly. A slight increase in the per-
centage activity was evident, but the lower lethal limit was not markedly shifted,
nor was the value at which stress was first observed altered.
342
RUDOLF S. SCHELTEMA
The lower lethal limit of salinity among veliger larvae of N. obsoletus was
determined by methods similar to those used for the adult snails. The criterion
used to determine the effect of salinity upon the larvae was their swimming activity.
Fifty larvae shortly after their emergence from the egg capsule were placed in
400 ml. of sea water, the salinity of which was adjusted by the addition of tap water.
The salinities tested ranged between 8.5% and 33.0% and were spaced at intervals
of roughly 6%o in the earlier and 3%o in the later experiments. The temperature
throughout was between 25 and 26 C., which is near the optimum for growth.
100 r
80
jg
<0
^
60
^40
20
10 20
SALINITY %
30
FIGURE 1. Inhibition of activity in adult Nassariits obsoletus resulting from reduced
salinity at about 20 C. The graph illustrates the percentage snails active following a four-hour
exposure period.
RELATIONS! I IF' OF SALINITY TO LARVAL SURVIVAL
343
100r
80
60
<0
^
kj
40
20
10 20
SALINITY %
30
FIGURE 2. Inhibition of swimming in larvae of Nassarius obsolctus resulting from reduced
salinity at 25-26 C. The larvae are those taken shortly after their emergence from the egg
capsule. The results are following a 10-hour exposure period.
Larvae for all the experiments originated from water of 32% c salinity. At the
end of 10 hours the dish containing the larvae was placed under a bright light and
those swimming were counted. The results of these experiments are shown in
Figure 2. The greatest decrease in the percentage of swimming larvae falls be-
tween I4%o and 15.S%c salintity. Below 10%c no larvae were ever seen swimming
after the 10 hours of exposure.
The response of the late stage creeping-swimming larva of N. obsoletus was com-
pared with that of the early veliger just after its emergence from the egg capsule.
344
RUDOLF S. SCHELTEMA
These further experinirnts differed only in detail from those already described.
Five-centimeter petri dishes we- re tilled with dilutions of sea water ranging from
6.6%o to 33.0%o and in each, 10 veligers were placed. Into one sequence of
dilutions were pipetted the early larvae; into the other, veligers which had com-
pleted their development to the creeping-swimming stage. The latter were reared
in the laboratory for 19 days at 24 C. according to the method already described
(Scheltema, 1962a).
TABLE I
Activity indexes* of Xassarius obsolctus veliger larvae <;.s n function of salinity
Early pelagic larvae
(1-3 days after emergence from egg capsule;
Salinity
1 min.
20 min.
1 hour
3 hours
Mean for 3 hours
6.6
1
0.3
9.0
1
1
0.5
11.0
1.5
1
2
1.1
13.2
2
2
3
1.8
16.5
1
3
3
3
2.5
19.8
3
4
4
4
3.8
26.4
4
4
4
4
4.0
33.0
4
4
4
4
4.0
Creeping-swimming stage**'
6.6
0.0
0.0
0.0
0.0
0.0
9.0
0.4
0.0
0.0
0.0
0.1
11.0
0.4
0.0
0.0
1.0
0.4
13.2
0.0
0.4
0.2
2.6
0.8
16.5
3.0
2.8
3.4
3.9
3.3
19.8
3.0
2.0
3.8
4.0
3.2
26.4
4.0
4.0
3.9
3.5
3.9
32.0
4.0
4.0
3.9
3.5
3.9
* The definition of this term is given in the text.
** The values in these experiments were based on evaluation of each individual larva's per-
formance, while those of the r.u-lv larvae were simultaneously estimated by assigning a value to
all the larvae in the dish.
The results of these experiments were expressed in terms of "activity indexes"
which were recorded at the beginning of the experiment and after 20 minutes, one
hour and three hours. The following numerical values were used to describe the
responses of the larvae and to compute the "activity indexes": 0, no movement of
velar cilia; 1, cilia of velum moving but not vigorously enough to allow the larva
to swim; 2, larva moving sluggishly along the bottom and sides of dish or, if
creeping-swimming stage, ilicn responding immediately to the touch of a pin; 3,
actively swimming or creeping; and 4, very actively swimming or creeping. All
examinations were made under bright light.
Results of one such experiment are summarized in Table I. A mean activity
index of between 2.5 and 4.0 indicates the "normal" range of behavior. The
RELATIONSHIP OF SALINITY TO LARVAL SURVIVAL
345
activity indexes of the ne\v and old larvae as a function of salinity have been
plotted together in Figure 3. This graph shows that there is no significant
difference in the activity of the two ages of larvae relative to the salinity. A sharp
decrease in activity occurred hetween 13.5',, and 16. S/^ salinity. Similar experi-
ments of longer duration (38 hours) fully confirmed the results shown here.
I
X
K
fc:
<o
^
/
/
/
8 EARLY LARVAE
'CREEPING SWIMMING
LARVAE
'
10 20
SALINITY %
30
Fiut'KK 3. Relationship of the "activity index" of early and creeping-swimming larvae of
Nassarius nbsolctus to salinity. The graph illustrates the average "activity index" resulting from
a series of observations over a period of three hours.
EXPERIMENTS ON THE EFFECT OF SALINITY n-ox LARVAL GROWTH OF
NASSARIUS OBSOLETUS
The larval life of Nassarius obsoletus can be divided into two periods. The
first of these is a phase of rapid growth and external development leading to the
creeping-swimming or veliconcha stage (Scheltema, 1962a). During this period
the growth rate is essentially constant (Fig. 4). This is followed by a second
period of very slow growth and no apparent further external morphological change.
The beginning of the second period is evident from the completion of the develop-
346
RUDOLF S. SCHELTEMA
ment of the foot and from the behavior of the larvae, namely, frequent creeping on,
and inspection of, the bottom .
The length of the first period is determined by those conditions which control
larval growth. The length of the second period varies greatly, at least two-fold in
N. obsolctus, and depends upon the encounter by the larva of a sediment suitable
for post-larval life (Scheltema, 1961 ). Under favorable conditions metamorphosis
may occur very near the beginning of the second period. The total length of
700 r
>100% MORTALITY
O LARVAE GROWN AT 32.9 %
A LARVAE GROWN AT 24.2%
LARVAE GROWN AT 20.9%
LARVAE GROWN AT 17.7%
6 9 12
TIME IN DAYS
15
18
FIGURE 4. Increase in length of Nassarius obsolctus veliger larvae from the time of
emergence from egg capsules to the completion of their development to the creeping-swimming
stage. This is the first pelagic phase, during which growth occurs at a rapid and nearly
constant rate. Each curve shows the result at a different salinity as indicated by the
conventions.
RELATIONSHIP OF SALINITY TO LARVAL STRYIVAL
347
larval life consequently is not determined solely by the growth rate, but also by the
opportunity for metamorphosis upon a favorable substratum. In investigating the
effect of salinity on the larvae, I have confined my attention only to the period of
rapid and constant growth rate.
Laboratory experiments on the growth rate of veliger larvae are possible only
after techniques for their mass culture are worked out (Scheltema, 1962a). The
veliger larvae of N. obsolctus were grown in a series of 10-liter vessels with
salinities ranging from that minimal for survival to that of full-strength sea water.
It was soon found that the larvae held at a salinity of less than \6%o did not
survive more than a few days. Consequently the minimum average salinity in the
experiment reported here was \7.7% and the remainder of the series had salinities
of 20.9%c, 24.2% , 26.2% and 32.8% c . All larval cultures were fed the euryhaline
diatom, Phaeodactylum tricornutum, from the same algal culture.
TABLE II
Length in microns of Nassarius obsoletus throughout larval development
as a function of the salinity
Mean
salinity
%o
Age in days
3
6
9
12
15
18
17.7
278 4*
291 4
363 8
429 7
20.9
278 4
312 6
401 6
433 7
468 6
501 6
552 8
24.2
278 4
458 7
492 8
556 9
613 10
665 10
26.2
278 4
447 6
487 9
543 8
586 6
32.9
278 4
343 4
446 5
502 8
615 8
643 8
683 9
* One standard error is indicated on all values of this table.
The mean temperature of the veliger cultures during this experiment, which
extended over a period of 18 days, was 23.1 C. The maximum difference in
water temperature measured during the course of the experiment was 1.1 C.
However, since all cultures were kept together in the same temperature bath, the
same fluctuations were experiencd by all. Maximum temperature differences
between cultures were 0.5 C, but the mean difference was only 0.2 C.
At the lower values, the salinity in the cultures never varied more than 0.5%c
from the mean ; in cultures at salinities higher than 24%o, the maximum deviation
from the mean value never exceeded 0.7%c. Growth of the larvae was deter-
mined by measuring the maximum shell dimensions at three-day intervals with
an ocular micrometer at a magnification of 100 X. This measurement, hereafter
termed length, was made on an aliquot of 30 larvae from each culture. Previous
measurements have shown this to be an adequate sample size.
The results of the experiment (Table II) show that among salinities above
24% c there is no statistically significant difference in length. As the salinity
reached 2l.Q% c , the difference becomes significant. Below 21.0% C , the data indicate
substantial decrease in shell growth rate. Under the conditions of the experiment,
completion of larval development to metamorphosis did not occur at a salinity of
177V
.us
RUDOLF S. SCHELTEMA
The pertinent data are summarized by means of growth curves in the graph
of Figure 4. Here the vertical lines indicate two standard errors. The difference
between the two curves above 2\%c with those of 2\% c and less is quite evident, and
the statistical significance is conspicuous.
The results of two additional experiments, similar to the one just described
above, together with the data from the first experiment, are summarized in Table
III. In each of the additional experiments, two cultures of veligers were started
simultaneously with larvae obtained randomly from the same collection of egg
capsules. The initial size of the larvae in the two cultures of an experiment were
consequently the same. Development previous to emergence of larvae from the
TABLE 1 1 1
Percentage inhibition of growth in Nassarius obsoletus larvae resulting from the lowest salinity
at which development is completed to metamorphosis
Expt.
no.
Temp,
range
C.
Age of
larvae
at end
of expt.
Length
n at
begin
expt.
A
B
Percent-
age inhi-
bition
(I)
Mean
salinity
Length
n at end
expt. (A)
Total
growth*
(A A)
Mean
salinity
%o
Length
/i at end
expt. (B)
Total*
growth
(AB)
1
II
III
23.0-24.0
19.5-21.3
26.1-28.0
18
19
12
278
270**
249
32.9
33.1
33.2
6839***
7014
5455
405
431
296
20.9
21.5
21.3
5528
634 6
504 8
274
364
255
32.1
15.5
13.8
Sum
Mean
61.4
20.5
* This denotes the difference between the initial length at the time of emergence from the
egg capsule and the length at the end of the experiment.
** In this experiment only the length of the larvae at the termination of the experiment is
known; the assumed length of 270 /* is the usual length of larvae at the time of emergence from
the egg capsule. However, even if extreme values are assumed, the percentage difference in the
final column is altered by no more than 1%.
*** One standard error is indicated.
egg capsules was at room temperature. The unusually small initial size of the
larvae in experiment III is a peculiarity of that particular collection of egg capsules
and is probably related to the time at which they were deposited within the breeding
cycle of the female snails.
In one of the two cultures in each experiment, larvae were grown at the
salinity of normal sea water. This culture is designated as "A" in each of the
experiments of Table III. In the other culture, designated "B" in Table III, the
larvae were grown at a reduced salinity near 2\%o. Both cultures in each experi-
ment were terminated at the same time. This was done near the end of the period
of constant growth rate in the high salinity culture "A" of each experiment.
The percentage inhibition, /, due to the reduction of salinity is shown for each
experiment in the right-hand column of Table III and was computed by the
relationship
A A
x
RELATIONSHIP OK SALINITY TO LARVAL SURVIVAL
where &A is the change in length of shell between the beginning and end of the
experiment among larvae maintained at sea-water salinities, and A# is the change
in shell length of larvae held at a minimum salinity required for completion of
development. Table III shows that maximum inhibition was obtained at a tem-
perature range of between 23 and 24 C, which is near the optimum for growth
of the larvae of N. obsolctus (Scheltema, 1963). At both higher and lower tem-
perature ranges there \vas substantially less inhibition in growth. However, owing
to the large differences in larval growth rate frequently obtained between experi-
ments, a direct effect or interaction of temperature on growth inhibition by reduced
salinity cannot be assumed without further experiments. The results show that
at the lowest salinity at which development to metamorphosis was completed, an
average of 20.5% inhibition of growth occurred.
DISCUSSION
Salinity as a limiting factor to distribution
The upstream distribution of most organisms that live within estuaries is seem-
ingly related to salinity. However, mere correspondence between salinity values
and the distribution of a particular species cannot in itself be taken as sufficient
evidence that salinity is limiting. To show this, it is necessary to discover the
extremes tolerated by an organism throughout its life history.
Thorson (1946, p. 472) has suggested that the larval stage may limit the dis-
tribution of bottom species, as this stage is "the weakest link of the chain." Experi-
ments upon the salinity lethal to larval and adult N. obsoletus, however, showed
no large difference between their lower tolerances. Such differences which did
appear might be accounted for by the previous acclimation of the adult snails to a
lower salinity or by the inadequacy of the techniques in making such small dis-
tinctions. The lower lethal salinity did not change significantly as larval develop-
ment progressed (Figs. 2 and 3).
The known upstream distribution of N. obsoletus into estuaries in many in-
stances seems to correlate well with the lower lethal salinity determined in the
laboratory. Hence, Pfitzenmeyer (1961) found the species at locations in Chesa-
peake Bay where the summer salinity was 14.6/ce. On the other hand, in certain
estuaries on Cape Cod snails do not ascend farther up than a summer bottom
salinity of \7%o, and in such instances salinity is probably not the factor limiting
distribution. In order to make valid comparisons, laboratory results must be
related to bottom salinities in areas where the seasonal extremes are known.
Salinity and larval growth rate
Growth of N. obsoletus is inhibited only as the lower limit of salinity tolerance
is approached (Scheltema, 1962b). Thus, it was not until the salinity was near
2Q% that any significant effect on growth rate was noticed. Although not directly
investigated, the decreased rate of growth in N. obsolctus is not likely to be re-
lated in any simple way to osmotic activity because marine mollusks, insofar as
known, have no active osmotic control involving the expenditure of energy
(Prosser et al., 1961 ). The mortality of larvae at salinities below 20%o was high.
350
RUDO1 }' S. SCHELTEMA
No larvae survived beyond the intermediate stage of development in laboratory
culture, although growth proceeded up until the ninth day at 17 ' ,7%o salinity. The
inhibition of growth attributable to the reduction of salinity amounted on the
100
80-
60-
40-
Nassarius Obsoletus
60-
40-
20-
Venus Mercenaria
,
30
!
35
SALINITY %
FIGURE 5. Percentage growth obtained at various reduced salinities relative to the
maximum growth obtained at optimal salinity conditions in the gastropod, Nassarius obsolctu?
Say and pelecypod, Venus mcrccnaria L. Data for V '. mcrccnaria are from Davis (1958), p. 301,
Fig. 1. Growth data for each species were used only if more than 5% of the larvae in the
culture completed development to metamorphosis. The data refer to 15 days after the beginning
(jf planktotrophic life in N. obsolctus (i.e., creeping-swimming stage) and 12 days after
fertilization in V. mcrccnaria. The different conventions indicate values for individual series
of experiments. The curves are only intended to he suggestive.
RELATIONSHIP OF SALINITY TO LARVAL SURVIVAL
351
TABLE IV
Maximum differences of larval growth rate attributable to various ecological factors
(Average values of I from experimental data}
N.
obsoletus
V.
mercenaria
Physical characteristics
Temperature
Range within which development is completed
Average difference in growth rate between optimum and
minimum required for complete development
Salinity
Range within which development is completed
Average difference in growth rate between optimum and
minimum required for complete development
Extreme difference in growth rate observed between opti-
mum and minimum required for complete development
17.5 to 30 C.*
50%*
20%
13 to 40%
18 to 30 C.**
60%**
M5.0V**
34%***
22 to 45%***
Biological characteristics
ca. 50%
(preliminary
estimation)
17.7%****
51.2%****
29.7%****f
Up to 75%ft
Concentration of algal food
(Differences between optimum and minimal growth
obtained at concentrations between 2.5 X 10~ 3 and
40 X 10~ 3 mm. 3 packed cells per 3-1. culture)
Isochrysis galbana
Monochrysis lutheri
Chlorella sp. (causes inhibition of growth and death of
larvae at highest concentrations)
Phaeodactylum tricornutum (data from relative concentra-
tions only)
Species of algal food
(based on 10 species of or combination of species when equal
packed cell volumes were used)
* Scheltema (1963), p. 17, Fig. 2.
** Loosanoff et al. (1951), p. 71, Table III; Loosanoff (1959), p. 315, Fig. o.
*** Davis (1958), p. 301, Fig. 1.
**** Davis and Guillard (1958), p. 302, Fig. 6.
f This figure represents difference in growth at concentrations between 2.5 X 10~ 3 and
20 X 10~ 3 mm. 3 per 3-liter culture. At higher concentrations larvae did not survive.
ft Davis and Guillard (1958), p. 298, Fig. 3; p. 299, Fig. 4.
Because differences in the nutritional value of the algal food cells used in
growth experiments are not readily controlled (Walne, 1963), it is not possible
to compare the results from one series of experiments directly with the next without
elaborate experimental procedures. A direct comparison between most series of
growth experiments usually shows large discrepancies. Only cultures of larvae
simultaneously grown using the same source of algal food can be directly com-
pared with one another. It is possible, however, to compare differences in com-
puted growth rates. Likewise the per cent inhibition, I, computed from the equa-
tion given above, can be directly compared if the differences in length are derived
352 Kl'DOI.K S. SCHELTEMA
from samples of similar size. Using this kind of information it is also possible to
compare the relative importance of reduced salinity to growth between species of
mollusks. In Figure 5 this has been done for two species which show similar
distributions within estuaries along the Atlantic coast of the United States : the
data of Davis (1958) on the growth of larvae of the pelecypod, Venus mercenaria,
are compared with growth data from the larvae of N. obsoletus. The conclusion
may be made that salinity little affects larval growth in either species until the
lower limit of salinity tolerance is approached. Only the lower third of the
salinity range has any marked inhibitory effect on growth and there is no simple
linear relationship between growth and the salinity level. The similarity in
response of the two species, V . mercenaria and N. obsoletus, is striking.
The importance of salinity relative to other factors affecting larval growth
An indication of the relative importance of salinity to larval growth can be had
by comparing its maximum effect relative to that of some other factors known to
control growth rate of N. obsoletus and V '. mercenaria. By tabulating the values for
maximum percentage difference obtained from that of optimum growth, the im-
portance of various ecological factors in limiting growth rate becomes apparent.
This is shown in Table IV. Here the range within which completion of develop-
ment occurs is given for physical characteristics of the environment, and the
percentage values are average maximum differences in growth attributable to these
physical factors. Differences in growth rate under different biological conditions
for which data are available, viz. concentration and species of algal food, are given
within the limits of concentrations indicated. The maximum inhibition of growth
varies with the algal species. On the basis of the figures given, the concentration
and the species of algal food usually affect growth rate of V . mercenaria much
more than any of the physical factors of the environment. There is preliminary evi-
dence that this is also true for N. obsoletus larvae. The food value of algal cells
to mollusk larvae in relation to the conditions under which the algal cells were
grown is not yet known (see Walne, 1963). The table shows that the importance
of low salinity in inhibiting growth rate, within the limits in which development
of the larvae is completed, is certainly minimal, less than any other factor in the
environment known to retard growth of the larvae.
This work is dedicated to the memory of G. Francis Beaven, who in his quiet
way first interested me in the relationship between salinity and the distribution
and survival of estuarine organisms.
SUMMARY
1. There is no large difference between the lower lethal salinity for the veliger
larva and the adult of Nassarins obsoletus. The region of stress in snails is be-
tween I2.5%o and 13.5'vr. ; that of the early larva is between 14.0/c and I5.5%o.
Throughout larval development no change occurred in the value of the lower
lethal salinity.
2. Difference in growth rate of X. ohsolctus larvae observed at salinities above
24 r / ( ( are usually slight. However, at 21 ( ,< ( and less there is a statistically sig-
RELATIONSHIP OF SALINITY TO LARVAL SURVIVAL
nificant drop in growth rate, while at a mean salinity of \7.7% , it was not pos-
sible to rear the larvae to the completion of development and metamorphosis. The
maximum inhibition of growth attributable to the affects of salinity, within the
range at which development of the larvae is completed, is between approximately
13% and 40% and averages about 20%. This is less than that of other ecological
factors known to retard growth.
3. The net result of reduced salinity, within the lower third of the range at
which the larval development of N. obsoletus is completed, is an increase in the
length of time to reach the creeping-swimming stage which precedes metamorphosis,
and an increased mortality of larvae as the limit of salinity tolerance is reached.
4. A comparison of data from N. obsoletus with that of another molluscan
species, the pelecypod Venus mercenaries, which is found at approximately the same
salinities within Atlantic coast estuaries along the United States, shows striking
similarities.
LITERATURE CITED
AMEMIYA, I., 1926. Notes on experiments on the early developmental stages of the Portuguese,
American and English native oysters, with special reference to the effect of varying
salinity. /. Mar. Biol. Assoc., 14: 161-175.
BEAYEN, G. F., 1946. Effect of Susquehanna River stream flow on Chesapeake Bay salinities and
history of past oyster mortalities on upper bay bars. Proc. Nat. Shellfish. Assoc..
37:38-41.
BLUM, H. F., 1922. On the effect of low salinity on Teredo navalis. Univ. Cat. Pub. Zool, 22 :
349-368.
CARRIKER, M. R., 1951. Ecological observations on the distribution of oyster larvae in New
Jersey estuaries. Ecol. Monogr., 21 : 19-38.
CLARK, A. E., 1935. Effects of temperature and salinity on early development of the oyster.
Prog. Kept., Atl. Biol. St., St. Andrews, N. B., No. 16 : 10.
DAVIS, H. C, 1958. Survival and growth of clam and oyster larvae at different salinities.
Biol. Bull, 114:296-307.
DAVIS, H. C., AND A. D. ANSELL, 1962. Survival and growth of larvae of the European oyster.
O. ednlis, at lowered salinities. Biol. Bull, 122: 33-39.
DAVIS, H. C., AND R. R. L. GUILLARD, 1958. Relative value of ten genera of microorganisms
as food for oyster and clam larvae. Bull. Fish and Wildl. Ser., 58: 293-304.
HASKIN, H. H., 1964. The distribution of oyster larvae. Symposium on Experimental Ecology,
Narragansett Mar. Lab., Grad. School Oceanogr., Univ. of R. L, Occ. Pub. No. 2.
KORRINGA, P., 1952. Recent advances in oyster biology. Quart. Rev. Biol., 27: 266-308.
KUNKLE, D. E., 1957. Vertical distribution of oyster larvae in Delaware Bay (Summary).
Proc. Nat. Shellfish Assoc., 48: 90-91.
LOOSANOFF, V. L., 1959. The size and shape of metamorphosing larvae of Venus (Mercenaria)
mcrcenaria grown at different temperatures. Biol. Bull., 117: 308-318.
LOOSANOFF, V. L., W. S. MILLER AND P. B. SMITH, 1951. Growth and setting of larvae of
Venus merccnaria in relation to temperature. /. Mar. Res., 10: 59-81.
XELSON, T. C., AND E. B. PERKINS, 1930. The reaction of oyster larvae to currents and to
salinity gradients. Anal. Rec., 47: 288.
PFITZENMEYER, H. T., 1961. Benthic shoal water invertebrates from tidewater of Somerset
County, Maryland. Chesapeake Sci., 2: 89-94.
PROSSER, C. L., AND F. A. BROWN, JR., 1961. Comparative Animal Physiology. W. B. Saunders
Co., Philadelphia, ix + 688 pp.
RAO, K. V., 1951. Observations on the probable effect of salinity on the spawning development
and setting of the Indian backwater oyster, Ostrea madrasensis Preston. Proc. Indian
SCHELTEMA, R. S., 1961. Metamorphosis of the veliger larvae of Nassariits t >bs!ctns (Gastro-
poda) in response to bottom sediment. Biol. Bull., 120: 92-109.
354 RUDOLF S. SCHELTEMA
SCHELTEMA, R. S., 1962a. Pelagic larvae of New England interticlal gastropods. /. Nassaritts
obsolctus Say and Nassarnis vibcx Say. Trans. Amcr. Microsc. Soc., 81: 1-11.
SCHELTEMA, R. S., 1962b. Environmental factors affecting length of pelagic development in the
gastropod, Nassarius obsolctus. Amcr. Zoo!., 2: 445.
SCHELTEMA, R. S., 1963. Larval development. Summary of Investigations conducted in 1962,
Woods Hole Oceanographic Institution Ref. 63-18,, pp. 15-19. (Unpublished manu-
script.)
SCHELTEMA, R. S., 1964. Feeding and growth in the mud-snail Nassaritis obsolctus. Chesapeake
Sci.,5: 161-166.
SEND, H., J. HORI AND D. KUSAKABE, 1926. Effects of temperature and salinity on the
development of the eggs of the common Japanese oyster, Ostrea gigas Thunberg.
/. Fish. Inst. Tokyo, 22: 41-47.
STICKNEY, A. P., 1964. Salinity, temperature and food requirements of soft-shell clam larvae
in laboratory culture. Ecology, 45: 283-291.
THORSON, G., 1946. Reproduction and larval development of Danish marine bottom invertebrates
with special reference to the planktonic larvae in the Sound (0resund). Medd. Komm.
Damn. Fiskcriog Ilavundcrs., Ser. Plankton, 4: 1-523.
TURNER, H. J., AND C. J. GEORGE, 1955. Some aspects of the behavior of the quahaug, Venus
incrccnaria, during the early stages. Eighth Rept. Inv. Shell Fish. Massachusetts,
pp. 5-14.
WALNE, P. R., 1963. Observations on the food value of seven species of algae to the larvae of
Ostrea cdulis. J. Mar. Biol. Assoc., 43: 767-784.
WELLS, HARRY W., 1961. The fauna of oyster beds, with special reference to the salinity
factor. Ecol. Monogr.. 31 : 239-266.
PHYSIOLOGICAL SALT SOLUTION FOR THE LAND CRAB,
GECARCINUS LATERALIS
DOROTHY M. SKINNER, DONALD J. MARSH AND JOHN S. COOK
Department of Physiology and Biophysics, Nezv York University Medical Center, New York,
Neiv York 10016, and The Lerncr Marine Laboratory, Bimini, Bahamas
The land crab, Gecarcinus later alls, is an active responsive animal until it
approaches ecdysis ; in the few weeks before and after ecdysis, however, the animal
becomes lethargic (Bliss, 1962). These variations in activity may well be related
to the marked changes in the metabolism of somatic muscle during molting (Skinner,
1962; 1963a, 1963b). In order to investigate the physiology of this muscle it has
first been necessary to develop a Ringer's solution appropriate to the animal. This
paper describes analyses performed on Gecarcinus serum. Observations on osmo-
regulation are included. From these data a Ringer's solution has been devised
and tested.
MATERIALS AND METHODS
1. Animals
Some specimens of Gecarcinus lateralis were collected in the field at Bimini
and were used immediately at the Lerner Marine Laboratory. Other specimens
were shipped from the Bermuda Biological Station to New York and were housed
in covered aquaria containing sand moistened with tap water. A fingerbowl of sea
water was available in each tank ; where indicated, tap water was substituted for
sea water.
2. Preparation of blood serum
Blood was collected from the cut appendage of an animal which had been
acutely chilled to prevent autotomy of the cut limb. The clot was mechanically
disrupted and sedimented by centrifugation.
3. Osmolality, sodium, potassium and chloride
Immediately after preparation, the osmolality of the serum was measured in a
Fiske osmometer. Concentrations of sodium and potassium in the serum were de-
termined by standard flame-photometric methods, using LiCl as an internal
standard.
Chloride was determined by the Cotlove titrimetric method (Cotlove et al..
1958). Initial attempts to determine chloride concentration of untreated blood
serum led to results varying by as much as 15% on five replicate samples. Since the
protein concentration of Gecarcinus serum is high and variable (2% to 10%,
unpublished data), we thought that protein might be interfering with the analyses.
355
SKINNER, MARSH AND COOK
Consequently, the protein precipitated by the nitric-acetic acid reagent used in the
analysis was homogenized to free any trapped chloride and removed by centrifuga-
tion. Ali(|uots of the supernatant were used for the titration. This procedure
reduced the variability between replicate samples to less than 2%.
4. Calcium and magnesium
(a) Preparation and characterization of an ultrafiltrate. Blood was ultrafiltered
to obtain a value for free calcium and magnesium without including divalent ions
associated with proteins. Three-inch dialyzer tubing (average pore diameter 48 A)
was cut along its edge, giving a piece 6 inches wide. This was shaped into a sack
and inserted into the top of a 12-ml. conical centrifuge tube. One to 2 ml. of blood
were introduced into the sack which was then tightly stoppered and centrifuged.
The first fluid collected after bringing the centrifuge to speed was set aside as
possible condensate from the tubing. TCA was added to each of these initial
collections. In the rare event that any precipitate formed (indicating the presence
of protein and hence a leak in the system), the sample was transferred to another
dialysis sack. The tubes were then spun at 3000 rpm in a model CM International
centrifuge for two hours. Heating was prevented by packing the drive shaft of
the centrifuge in dry ice during the centrifugation. The rate of ultrafiltration was
about 0.025 nil. hr.' 1 ml. serum' 1 . The ultrafiltrate obtained was colorless and
contained no more than .06% protein (as determined by the method of Lowry et al,
1951), representing about \% of the protein initially present in the serum. Within
the limits of experimental error, the alkali metal concentrations in the ultrafiltrate
were the same as those in whole serum. Since the small correction for serum water
would be opposite to that applied for the Donnan equilibrium, the similarity was an
expected result, and indicated that there was no significant evaporation of the
ultrafiltrate during preparation.
(b) Assay method. The dye Eriochrome Black T is pink when chelated to
divalent cations and blue when free in solution after the cations have been removed
by a stronger chelating agent. With this dye as an indicator, the sum of calcium
and magnesium was titrated with EDTA at a basic pH in the presence of cyanide
( Ames and Nesbett, 1958). Calcium alone was determined titrimetrically on sepa-
rate aliquots of each sample, using 2-hydroxy-l-(2-hydroxy-4-sulfo-l-naphthyl-azo)-
3-naphthoric acid (HHSNN, Fisher Scientific Company) as indicator and EGTA
ictliylene glycol bis ( /^-aminoethyl ether )-N, N-tetraacetic acid) as the titrant
i : Weber and Her/., 1963). Magnesium was obtained by subtracting the calcium
value from the total. Standard curves were run with each set of experimental
samples.
5. Sul fate
Proteins were precipitated from serum with perchloric acid (0.7 M final concen-
tration). The supernatant was neutralized with KOH and the concentration of
inorganic sulfate measured according to the method of Jones and Letham (1956V
In four experiments, where- known amounts of sulfate were added to crab serum.
101.5% of the added sulfate was recovered.
LAND CRAB SERUM ELECTROLYTES
357
6. pH, pCOt, pO*, and bicarbonate
Blood was collected by immersing a cut appendage below the surface of paraffin
oil saturated with water. The clot was mechanically disrupted and the serum
transferred anaerobically to a cuvette housing a Clark polarographic O 2 electrode,
a Severinghaus CCX electrode, and a glass pH electrode, all of which were read out
by means of a Beckman model 160 gas analyzer. The pH of any sample which
differed significantly from the others was measured independently with a Radio-
300
450
U)
400
o
330
I
300
No*-.
700 800 900
MILLIOSMOLES/KO. HO
1000
FIGURE 1. Sodium and chloride as functions of osmolality in the serum of Gecarcinus
latcralis. Sodium data: closed circles; chloride data: open circles. Regression lines were
fitted to the data by the method of least squares.
meter pH meter ; in such cases the two readings always checked within 0.02 pH unit.
In addition pH measurements were made after equilibration of samples with varying
concentrations of CO 2 in air, in order to obtain the apparent pK. With this pK and
the measured pH and pCO 2 , the bicarbonate concentrations were calculated.
7 '. Inorganic phosphate
Protein was precipitated from serum with TCA (trichloroacetic acid) at a
final concentration of 5%. Inorganic phosphate was determined by the method of
Fiskeand SubbaRow (1925).
358
SKINNER, MARSH AND COOK
RESULTS AND DISCUSSION
1. Osmolality, sodium, potassium and chloride
The osmolality of Gecarcinus serum varied from 610 to 1060 mosm/kg. H 2 O,
depending on environmental conditions. Sodium varied from 310 to 480 meq/L.
and, in any given animal, accounted for approximately one-half the total osmolality
(Fig. 1). Chloride, the principal serum anion, was also linearly related to the
osmolality hut was present at concentrations about 35 meq/L. less than the sodium
in the 12 sera analyzed for both ions.
Serum potassium varied from 7 to 15 meq/L. Figure 2 shows that the potas-
sium concentration also tended to vary with osmolality, but in this case the data were
proportionately more scattered and the interdependence was not as evident until
we obtained the data on osmoregulation described below.
13
ul
13
'in
co
o
CL
10
1000
600 700 800 900
MILLIOSMOLES/KG. HgO
FIGURE 2. Potassium as a function of osmolality in the serum of Gecarcinus lateralis.
During the initial phases of this work at Bimini, 21 animals sampled immediately
after they were caught in the field had an average serum sodium of 369 28 ( S.D.)
meq/L., while 8 animals kept on moistened sand (but with no other source of water)
for 48 hours before sampling had an average serum sodium of 456 26.3 (S.D.)
meq/L. This difference was highly significant and prompted further investigation
of the effects of environmental conditions.
In Bimini, Gecarcinus burrows in the sand some distance from the sea in an
area where the ground water is salty. Animals shipped to New York have,
shortly after arrival, a serum osmolality of approximately 830 mosm/kg. H..O.
A group of animals was kept from arrival in an aquarium with sea water x avail-
able in the water bowls ; after several weeks a blood sample was taken for osmolality,
sodium, potassium and chloride determinations. The animals were replaced in tanks
1 The sea water used was obtained from the New York Aquarium (Coney Island) and had
the following measured composition (in meq/L.) : Sodium, 375; potassium, 8.1; chloride, 460;
magnesium, 79.0 ; calcium, 16.4 ; osmolality = 860 mosm/kg. H 2 O ; salinity 27.\%c.
LAND CRAB SERUM ELECTROLYTES
359
with tap water in the bowls, and after 8 days (three animals) or 27 days (two
animals), the hlood collections and determinations were repeated. The results
(Table I) show that all four parameters decreased when only fresh water was
available, and that the decrease was greater after the longer exposure. These ex-
periments show that potassium, as well as sodium and chloride, does vary in the
same sense as the osmolality, a relationship not readily seen from the data in
Figure 2.
2. Calcium and magnesium
The mean value for free calcium in serum water of intermolt animals was
17. 2 2.4 (S.D.) meq/L. ; the mean value for free magnesium was 13.8 2.2
(S.D.) meq/L. (Table II).
TABLE I
Osmolality, sodium, potassium and chloride of Gecarcinus serum in animals given access
to sea water only for several weeks (I) and thereafter given access to tap water only (II)
Animal
Days of access
to tap water
Osmolality
(mosm/kg. HzO)
Sodium
(meq./L.)
Chloride
(meq./L.)
Potassium
(meq./L.)
1
8
I 1000
467
435
13.0
II 890
423
385
10.8
2
8
I 965
456
414
11.7
II 890
438
410
10.5
3
8
I 990
456
422
11.1
II 960
452
415
11.3
4
27
I 948
430
396
11.2
II 825
388
362
8.0
5
27
I 1058
457
418
11.5
II 895
430
385
10.0
These values are distinctly lower than those found by Gross (1963) for
Gecarcinus. The difference probably reflects the fact that Gross dialyzed the serum
against distilled water (for his method, see Gross, 1959), a procedure which
would be expected to release cations normally bound to protein.
We found that two premolt animals had calcium concentrations higher than the
average intermolt level, whereas the magnesium levels were the same at both stages
(Table II). After ecdysis, the calcium level fell while the magnesium level rose
more than 40%. Travis (1955) has described a similar pattern for calcium in the
pre- and postmolt periods for another crustacean, the spiny lobster. Although these
changes are of interest in the overall electrolyte metabolism of molting, we con-
sidered them too small to influence significantly the physiological effectiveness of a
Ringer's solution ; therefore we did not sample a larger series of pre- and postmolt
animals.
Son
SKINNER. MARSH AND COOK
I \BIJ- 11
i'J i ale in in and magnesium in Gecarcinus serum ultrafiltratc
Stage
Animal
Calcium
(meq./L. )
i
Magnesium
(meq./L.)
Intermolt
1
13.2
15.2
2
18.5
11.5
3
17.4
15.7
4
24.8
1(1. (i
5
1S.4
17.6
6
17.1
15.3
7
19.2
13.2
8
17.6
12.S
9
16.8
12.4
10
11
12
16.8
14.3
13.5
14.4
Avg: 13.8 db 2.2 (S.D.
Avg: 17.2 2.4 (S.D.i
Premolt
1
22.d
14.11
2
24. S
13.6
Avg: 23.4
Avg: 13.8
Post molt
1
18.4
17.6
2
20.11
18.0
3
18.8
Avg: I'M
23.2
Avg: 19.6
3. Inorganic snlfate
The results of 17 analyses are listed in Table III. Sera from 13 intermolt
j
animals had an inorganic snlfate concentration of 11. 18 0.66 (S.D.) meq/L.
Two premolt and two postmolt animals had similar values, indicating no variation
during the molt cycle.
4. pH, pCO z , pOn and bicarbonate
Gecarcinus blood serum has a relatively constant pH of 7.2 and a pCO 2 of 14
mm. Hg (Table IV). The wide fluctuations observed in the oxygen tension are
unexplained. They are probably not due to the mixing of "arterial" with "venous"
TABLE 1 1 1
Inorganic snlfate in Gecarcinus serum
Stage
Number of animals
Inorganic sulfate
Range
(meq./L.)
Average
(meq./L.)
Intermolt
Premolt
Postmoll
13
2
2
10.20-11.94
10.86-11.06
10.92-11.68
11.18 0.66 (S.n.)
10.96
11.30
[.AND CRAP, SERUM ELECTROLYTES
361
pH, pCO-2,
TABLE IV
bicarbonate in Gecarcinns serum
Animal
I>H
pCOz
(mm. Hg)
pO 2
(mm. Hg)
Bicarbonate
(meq./L.)
1
7.20
14
24
7.40
2
7.22
13
29
5.14
3
7.43
12
28
7.70
4
7.14
12
72
3.95
5
7.05
16
56
4.15
6
7.08
15
36
4.99
7
7.26
16
30
6.94
8
6.95
14
46
2.97
Averages
7.17
14
40
5.40
blood (if such terms can be used to describe the hemolymph of an arthropod),
since if mixing were the cause of the variability, we would expect low pO 2 values to
lie correlated with high pCO 2 values.
The pCO, is considerably higher than that of the sera of many other inverte-
brates (Spector, 1956; p. 270). The low pCO 2 of insects is probably due to the
direct oxygenation of every cell by tracheole penetration, while the low pCO 2 of
various marine Crustacea is probably due to the solubility of CO 2 in the sea water
bathing the gills.
To determine the site of the diffusion barrier for CO 2 in Gccarcinus, the
branchial chamber of an animal was flushed with 100% O 2 for 10 minutes before and
throughout the collection of the blood sample. The pO 2 of that serum was only 52
mm. Hg, while the pCO 2 was 13.5 mm. Hg. The maintenance of this high pCCX
in the blood despite the fact that the gill chamber was flushed free of CO 2 indicates
that the barrier lies between the gill chamber and the branchial chamber. Further
experiments will be performed to test this possibility.
5. Inorganic phosphate
The inorganic phosphate content of 31 serum samples collected from animals
in the field averaged 0.76 but ranged from 0.21 to as high as 2.08 mmols/liter
(Table V).
TABLE V
Inorganic phosphate in Gecarcinus serum
Stage
Conditions
Number of
animals
Inorganic phosphate
range
(mmoles/L.)
Average
Intermolt
Collected in field
31
0.21-2.08
0.76
Intermolt
Starved >3 dav-;
7
0.29-0.53
0.42
Premolt (D - D 4 ) 1
Day of ecdysis
Postmolt (A - Ci) J
Did not eat
after onset
of Do
8
1
12
0.33-0.78
0.42
0.34-0.66
0.50
0.42
0.51
362 SK1NXKK. MARSH AND COOK
Travis (1955) found that under controlled feeding conditions the level of in-
organic phosphate in the serum of the spiny lobster remained relatively constant
throughout the molt cycle. A decrease of 25% in the postmolt period was the
greatest fluctuation she observed. According to Travis, diet was the principal
factor which determined serum phosphate levels.
\Ye took our blood samples in the field within a few hours after the animals
had been collected ; therefore, the time and content of each specimen's most recent
meal probably accounted for the 10-fold variation in inorganic phosphate level.
More recently we have analyzed blood from a group of animals maintained in the
laboratory, where feeding conditions could be controlled. Sera from these animals
starved for three or more days showed much less variation in the inorganic phos-
phate concentration and were in the lower range of those collected in the field
(Table V).
There was no correlation of inorganic phosphate concentration with the molting
cycle. These data appear to be similar to those obtained by Travis for the spiny
lobster.
TABLE VI
Composition of Ringer's solution for Gecarcinus
Compound
mmols./L.
NaCl
430
K 2 SO 4
5
MgCl 2
7
CaCl 2
9
"Tris" buffer
10
The final pH is adjusted to 7.2 with 0.2 N maleic acid.
6. Preparation and physiological efficacy of the Ringer's solution
Based on the measurements above a Ringer's solution has been devised
(Table VI). 2 Regardless of the serum osmolalities (and corresponding ion con-
centrations) within the range of 610 to 1060 mosm/kg. H 2 O, there were no gross
behavioral differences in the specimens of Gecarcinus. Hence it appeared that a
Ringer's solution within this range should support normal neuromuscular activities.
We have selected a sodium concentration (430 meq/L.) and osmolality close to the
values observed in animals shortly after their arrival in the laboratory. The use of
chloride salts raised the concentration of chloride somewhat higher than any ob-
served in the animals. Since the final Ringer supported prolonged neuromuscular
activity, the high chloride does not appear to exert any deleterious effect.
2 Previous data published mi the ionic composition of Gecarcinus latcralis serum by Prosser
and Brown (1962; p. 60) were preliminary data obtained by J. W. Green in collaboration with
one of us (DAIS). Since for technical reasons we were not confident of the validity of some
of the numbers obtained at the time, we did not publish the data. However, we did make them
available to a few colleagues, one of whom submitted them for publication to Dr. Prosser.
Dr. Prosser published them in good faith without knowledge of their source. Before under-
taking the present work, we tested a Ringer's solution prepared from the values obtained
earlier and found that it did not support nerve or muscle function.
LAND CRAB SERUM ELECTROLYTES 363
The solution is brought to pH 7.2 with Tris(hydroxymethyl) aminomethane/
maleic acid, a buffer commonly used in crustacean Ringer's solution (Elliott an.l
Florey, 1956). The concentration of inorganic phosphate in Gecarcinus plasma
was too low to use it as an effective buffer. Indeed, the small concentration
prompted us to omit inorganic phosphate from the solution entirely. We have also
omitted bicarbonate from the Ringer since its buffering capacity at 5 X 10~ 3 M
would be small and would require in any case the maintenance of a constant pCCX.
The measured osmolality of the final solution was 850 mosm/kg. HoO.
A chela of an intermolt animal was removed and the nerve trunk in the merus
was freed of all surrounding tissue. Forty ml. of the Ringer were perfused through
the cut end of the propus to wash out blood. The nerve trunk was stimulated and
the contraction of the adductor muscles in the propus was observed intermittently
over a four-hour period. During the same period of time, sensory stimulation (i.e.,
light taps) in the region of the mechanoreceptors in the leg joints elicited action
potentials which could be recorded approximately 4 cm. down the sensory nerve.
Thus, axonal conduction, neuromuscular transmission, and muscular contraction
appear normal for up to four hours, at which time the experiments were terminated.
CONCLUSIONS
Summing the inorganic ions for an animal with an osmolality in the median
range, e.g., 850 mosm/kg. H 2 O, we find that the inorganic cations total about 450
meq/L. and the inorganic anions about 385 meq/L., leaving 65 meq/L. anionic
charge unaccounted for. Acidic amino acids contribute little to this charge since
they are present in low concentrations (ca. 0.05-0.10 mmol/liter total) and are
more than balanced by basic amino acids (ca. 0.13-0.74 mmol/liter, unpublished
data). The protein concentration in Gecarcimis serum is high and the isoelectric
points of all the proteins are not kno\vn. Most should be negatively charged at the
pH of the animal's plasma unless the isoelectric points are unusually basic. There-
fore negative charges on protein probably account for many of the undetermined
anions.
In a serum of osmolality 850 mosm/kg. H 2 O the total of all inorganic ions
is about 815 mmol/L. If we assume a rational osmotic coefficient of about 0.9
for these electrolytes, only 13% of the total osmotic pressure is unaccounted for.
Much of this will be made up by proteins, amino acids, glucose, and other commonly
occurring organic solutes. Therefore it is unlikely that any single organic compound
makes up an important fraction of the total osmotic pressure, as does urea in
elasmobranchs (Prosser and Brown, 1962; p. 142) and glycerol in some insects
(Wyatt and Meyer, 1959).
The clear dependence of sodium, chloride and potassium concentrations and of
osmolality on the nature of the available water supply indicates that Gecarcinus does
not regulate these concentrations about a critical set point. A corollary of this con-
clusion is the observation that all animals showed similar motor behavior regardless
of their plasma ion concentrations. It is of interest that the serum osmolality is al-
ways greater than that of the available water supply. Gecarcinus is a land animal
and evaporation at its gills undoubtedly leads to the observed hemoconcentration.
Gross' data (1963) show that concentrations of alkali metal cations are essentially
the same in urine as in blood over a wide range of blood concentrations. This
364 SKINNHIv. MARSH AND COOK
observation precludes the possibility that renal mechanisms compensate blood
changes.
Gross measured sodium and potassium in groups of Gccarcinns exposed to a
variety of environments; he concluded, as have we, that the concentrations of these
two ions are not closely regulated. Flemister (1958) immersed the animals in
aqueous solutions of various chloride concentrations and found that even after
several days the blood chloride did not equal environmental chloride. Under these
conditions Flemister noted that animals immersed in hypotonic sea water had
blood chloride concentrations greater than that of the environment, whereas animals
immersed in hypertonic sea water had blood chloride less than that of the environ-
ment. In his experimental situation the normal evaporative processes are pre-
vented. However, his data indicate, as do ours, that the plasma chloride concen-
tration decreases in a hypotonic medium and increases in a hypertonic environment.
Whether one concludes that Gecarcinus is capable of osmoregulation depends
to some extent on one's definition of the term. Serum ion and osmolality levels
are not maintained constant independent of the environment ; but not even in the
case of total immersion do they equilibrate with the environment. In their normal
terrestrial habitat evaporative losses can and do occur, and the animals appear to
compensate for these in the laboratory by spending some time in the available water
that the animals are capable of osmoregulation only to a limited extent (in part
by behavioral mechanisms), and that the resulting fluctuations in serum concentra-
We wish to express our appreciation to the staff of the Lerner Marine Labora-
tory, Bimini, where this work was initiated ; to Arnold Davidson for excellent
technical assistance ; to Dr. E. Bergofsky for performing some of the analyses and
Dr. M. Mendelson for performing some of the tests on the efficacy of the Ringer.
This work was supported by USPHS grant #AM 06268 to one of us (l)MS)
and by ONR assistance which made the preliminary work in the field possible.
SUMMARY
1. From determinations of the principal electrolytes and respiratory gases in
the serum of the land crab, Gecarcinus lateralis, a Ringer's solution has been
devised and found to be effective in supporting neuromuscular activity for at least
four hours in isolated preparations.
2. The animal is capable of a limited osmoregulation.
LITERATURE CITED
AMES, A., AND F. B. NESBETT, 1958. A method for multiple electrolyte analyses on small
samples of nervous tissues. /. Neurochem., 3: 116-126.
BLISS, D. E., 1962. Neuroenclocrine control of locomotor activity in the land crab Gecarcinus
Ititcmlis. Mem. Soc. Endocrinol., no. 12, Neurosecretion : 391-410.
COTI.OVE, E., H. V. TRANBRAM AND R. L. BOWMAN, 1958. An instrument and method for
automatic, rapid, accurate, and sensitive titration of chloride in biologic samples.
J. Lab. Clin. Mcd.. 51: 461-468.
KI.I.IOTT, K. A. C, AND E. FLOREY, 1956. Factor I inhibitory factor from brain. Assay.
Conditions in brain. Simulatint!, and antagonizing substances. J. Neurochem., 1:
181-192.
LAND CRA1J SERUM ELECTROLYTES
FISKE, C. H., AND V. SruK.\Ro\v, 1925. The colorimetric determination of phorphorus. ./.
Biol. Chem., 66: 375-400.
FLEMISTER, L. J., 1958. Salt and water anatomy, constancy and regulation in related crabs from
marine and terrestrial habitats. Biol. Bull., 115: 180-200.
GROSS, W. J., 1959. The effect of osmotic stress on the ionic exchange of a shore crab. Biol.
Bull, 116: 248-257.
GROSS, W. J.. 1963. Cation and water balance in crabs showing the terrestrial habitat.
Physiol ZouL, 36: 312-320.
JONES, A. S., AND D. S. LETHAM, 1956. A spectrophotometric method for the determination
of sub-micro quantities of sulphur with 4-amino-4'-chlorodiphenyl. Analyst, 81: 15-18.
LOWRY, O. H., N. J. ROSEBROUGH, A. L. FARR AND R. J. RANDALL, 1951. Protein measure-
ment with folin phenol reagent. /. Biol. Chem., 193: 265-275.
PROSSER, C. L., AND F. A. BROWN, JR., 1962. Comparative Animal Physiology. W. B. Saunders
SKINNER, D. M., 1962. The structure and metabolism of a crustacean integumentary tissue
during a molt cycle. Biol. Bull., 123: 635-647.
SKINNER, D. M., 1963a. Growth in a crustacean. Amer. Zool., 3: 71.
SKINNER, D. M., 1963b. In I'iro synthesis of protein in fully formed and developing muscle
during the molting cycle in the land crab Gecarcimis. J. Cell Biol., 19: 66A.
SPECTOR, W. S., 1956. Handbook of Biological Data. W. B. Saunders Co., Philadelphia.
TRAVIS, D. F., 1955. The molting cycle of the spiny lobster, PanuUrus argus Latreille. III.
Physiological changes which occur in the blood and urine during the normal molting
cycle. Biol. Bull., 109: 484-503.
WEBER, A. M., AND R. HERZ, 1963. The binding of calcium to actomyosin systems in relation
to their biological activity. /. Biol. Chem,, 238: 599-605.
WYATT, G. R., AND W. L. MEYER, 1959. The chemistry of insect hemolymph. III. Glycerol.
/. Gen. Phvsiol.. 42: 1005-1011.
CHLOROPLAST PIGMENTS AND THE CLASSIFICATION OF
SOME SIPHONALEAN GREEN ALGAE OF AUSTRALIA 1
HAROLD H. STRAIN
Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60440
With respect to their chloroplast pigments, the siphonaceous green algae of the
order Siphonales (class, Chlorophyceae) differ slightly from the common uni-
cellular and multicellular green algae (Strain, 1958, pp. 37, 162, 167). From this
standpoint of pigment composition, the Siphonales are not so closely related to the
other green algae as all the other uninucleate and multinucleate Chlorophyceae are
related to one another (Fritsch, 1935, pp. 60, 368; Smith, 1955, p. 101).
From the nature and the proportions of their chloroplast pigments, the
Siphonales are remotely related to the other siphoneous or coenocytic algae such
as the Vaucheriaceae (Strain, 1958, pp. 51, 169), which are alternatively classified
as Siphonales (Fritsch, 1935, p. 368) or as Heterosiphonales (class, Xanthophyceae
or Heterokontae) (Smith, 1955, p. 177; Taylor, 1960, p. 190). With respect to
their pigments, the Heterosiphonales are similar to a group of multicellular
filamentous algae known as the Heterotrichales (Tribonemataceae), also of the
class Heterokontae (Smith, 1955, p. 174; Strain, 1951, p. 254, 1958, p. 169).
This relationship, based on pigments, supports the contention that the Hetero-
siphonales (Vaucheriaceae) and the Heterotrichales (Monociliaceae and Tri-
bonemataceae) belong to the same class (Heterokontae) (Smith, 1955, p. 166).
With respect to pigments, Dichotomosiplwn tuberosus (A.Br.) Ernst, a fresh-water,
siphonaceous species, is related to the Siphonales (Strain, 1958, pp. 37, 167) (pre-
dominantly marine species), not to the siphonaceous Heterosiphonales (pre-
dominantly fresh-water species) (Fritsch, 1935, p. 369; Smith, 1955, pp. 101, 115;
Taylor, 1960, p. 190).
Like all the common green algae, and the higher plants as well, the species of
the Siphonales examined thus far contained chlorophyll a plus chlorophyll b. The
heterosiphonalean and heterotrichalean species contained chlorophyll a unaccom-
panied by other chlorophylls (Strain, 1958, pp. 37, 51, 167, 169). Like the com-
mon green algae, the coenocytic species of the order Siphonales contained the
principal xanthophylls neoxanthin, violaxanthin and lutein plus traces of zeaxanthin.
They also contained an additional xanthophyll, called siphonaxanthin, and an ester
of this pigment called siphonein. The heterosiphonalean and the heterotrichalean
species contained a group of unnamed xanthophylls not observed elsewhere (Allen
et al., 1964; Strain, 1958, p. 51). The green algae of the order Siphonales con-
tained much more a-carotene than ^-carotene. The algae of the heterokontaen
groups contained principally /^-carotene. Dichotomosiphon contained the same
chlorophylls and xanthophylls found in the Siphonales, but the principal carotene
was the /3-isomer (Strain, 1958, p. 167).
1 Based on work performed under the auspices of the U. S. Atomic KniT^y (.'
and the Australian Academy of Science.
366
PIGMENTS OF SOME SIPHONALEAN ALGAE 367
The siphonalean green algae available for the earlier studies (Strain, 1958, p.
167) included about 24 varieties and species. They represented 9 genera and 5
families. Except for Dichotomosiphon, obtained from Lake Michigan, these species
were indigenous to the coastal waters of California, Hawaii and Puerto Rico.
MATERIALS AND OBSERVATIONS
As an extension of the earlier studies, the pigments of several Australian
species of siphonaceous, green algae have now been isolated and compared with
the pigments described before (Strain, 1958). The organisms were collected at
various remote locations in the Southern Hemisphere (Womersley, 1959) at low
tide during the spring months, August through November, 1963. They were
examined soon after collection. The pigments were separated and compared by
chromatography in columns of powdered sugar with petroleum ether plus 0.5%
w-propanol as the wash liquid (Strain, 1958, p. 27). In the United States the
powdered sugar is sold as Confectioners Powdered Sugar. In Australia it is
available as Soft Icing Mixture and as Icing Sugar. The carotenes were separated
in columns of activated magnesia [Micron Brand magnesium oxide No. 2641
(Strain, 1958, p. 30) also sold as Sea Sorb 43 by Fisher Scientific Company].
Before the columns were packed, the magnesia was mixed with twice its weight
of heat-treated siliceous earth (Celite 545).
The individual pigments with their sequence (top to bottom) and color in
the columns of powdered sugar were :
Siphonaxanthin, red-orange
Neoxanthin, light yellow
Violaxanthin, light yellow
Siphonein, red-orange
Chlorophyll b, yellow-green
Lutein zeaxanthin, yellow
Chlorophyll a, green
a-Carotene + /2-carotene, yellow
The location of siphonein was previously reported below the chlorophyll b due
to mislabelling of the chlorophyll b and siphonein zones (Strain, 1958, p. 38).
Separate chromatographic experiments also revealed that siphonein and fucoxanthin,
the principal xanthophyll of diatoms and brown algae, are adsorbed together in
the sugar columns. Both pigments form zones of nearly the same color above the
chlorophyll b zone. When adsorbed together in sugar columns, these two xantho-
phylls are incompletely separated, even after prolonged washing with the petroleum
ether-propanol solvent. Reaction of the fucoxanthin, in ether solution, with con-
centrated hydrochloric acid, to yield a blue color in the acid layer, serves to dis-
tinguish the fucoxanthin from the siphonein, which does not yield a blue color.
The siphonalean algae that were examined are listed in Table I along with
the regions where they were collected.
All the species included in Table I yielded much more a-carotene than ^-carotene.
All these species except Caulerpa filifonnis contained siphonaxanthin and siphonein
in addition to the other chloroplast pigments found in green algae and higher
368
HAROLD H. STRAIN
plants (Strain, 1958, pp. 130, 157, 162). They yielded these pigments in the
chromatographic sequence indicated above. Chlorodesmis comosa yielded very
little of the siphonaxanthin and siphom'in.
Because of the absence of siphonaxanthin and siphonein in Caulerpa filijormis,
analyses were repeated several times. The organism was also collected from two
different stands on neighboring rocks, but the siphonaxanthin and siphonein,
found in other species of Caulerpa as well as in all the other species of the Siphonales,
could not be detected.
TABLE I
Algae of the order Siphonales, whose chloroplast pigments were determined.
and the locations where they were collected in Australia
Bryopsidaceae
Bryopsis sp.
Caulerpaceae
Caulerpa cupressoides (West) C.Ag.
Caulerpa distichophylla Sender
Caulerpa filiform is (Harv.) C.Ag.
Caulerpa lentillij'era ]. Ag.
Caulerpa racemos/t var. laetcvircns (Mont.) Weber-van
H/ilinieda discniden I Vvai^ne
Codiaceae
Chlorodesmis onin^a Harv. & Bail.
Codiuni ditthieae Silva
Codimn fragile (Suring) Hariot
Codiiini lurasii St.-tch.
Codimn liicus/i Setch.
Codium spongiosum Harv.
Cottesloe Beach ( Perth i
Heron Id. (Gt. Barrier Reef)
Cottesloe Beach (Perth)
Cronulla Beach (Sydney)
Redcliff (Brisbane)
Heron Id. (Gt. Barrier Rt.vi ">
Pt. Peron (Freemantle)
Heron Id. (Gt. Barrier Reef)
Heron Id. (Gt. Barrier Reef)
Pt. Peron (Freemantle)
Hungry Pt. Cronulla (Sydney)
Cronulla (Sydney)
Redcliff (Brisbane)
Heron Id. (Gt. Barrier Reef)
Cladoplwropsis herpestica (Mont.) Howe (Valoniaceae), collected at Redcliff
(Brisbane), yielded the pigments characteristic of the uninucleate green algae.
Siphonaxanthin and siphonein were absent, and /3-carotene was the principal
carotene isomer. These results conform to those obtained with other species of
(Strain, 1958, p. 164).
CONCLUSIONS
On the basis ot the species available thus far, siphonaxanthin and siphonein
are constituents of siphonalean green algae indigenous to remote regions both of
the Northern and Southern Hemispheres. The absence of these two pigments in
Caulerpa filijormis indicates that siphonaxanthin and siphonein are not definitive
characters for the classification of all the Siphonales. The preponderance of
a-carotene relative to /^-carotene is without exception in the marine Siphonales.
The fre.sh- \\ater Dichotomosiphon is an exception (Strain, 1958, p. 157).
The wide distribution of siphonaxanthin and siphonein in the species examined
(Table I) indicates that the Siphonales comprise a distinct group. This conclusion
PKiMKXTS OF SO.MK SIPHONALKAX
is supported by the preponderance of a-carotene over /3-carotenc in all the marine,
species.
The absence of siphonaxanthin and siphonein and the preponderance of /2-caro
tene in Cladophoropsis hcrpcstica agree with earlier analyses of other species
the Siphonocladales (Strain, 1958, p. 164). This result indicates that the
Siphonales stand apart from the Siphonocladales.
The universal occurrence of chlorophyll b along with chlorophyll a supports the
view that the Siphonales and the Siphonocladales are major divisions of the
Chlorophyceae. This relationship is supported by the occurrence of the same
xanthophylls, namely, lutein, violaxanthin and neoxanthin, in the Siphonales, in the
Siphonocladales and in all the other species of the Chlorophyceae.
There appears to be no relationship among the occurrence of particular
chloroplast pigments, the calcification of the organisms and the composition of
the structural polysaccharide in the marine Siphonales (Feldmann, 1946; Fritsch,
1935, p. 368; Miwa et al, 1960; Smith, 1955, p. 12).
The occurrence of chlorophyll a and /2-carotene in the Siphonales and in the
Hetero siphonales indicates a basic relationship between these two groups. This
relationship is akin to that existing among all autotrophic organisms in which
oxygen production is always associated with the presence of chlorophyll a and - or
^-carotene (Strain, 1951, 1958, p. 83, 1964).
In conjunction with the earlier pigment studies (Strain, 1958), the current
results support the classification of the Heterosiphonales with the Heterotrichales
in a class apart from the Chlorophyceae.
This work was made possible by a Senior Fellowship of the Australian Academy
of Science and by assistance from many Australian scientists. Dr. A. B. Cribb
identified the algae collected near Brisbane and Cronulla. Miss A. M. Baird, Dr.
Mary A. Pocock, Dr. G. G. Smith and Dr. H. B. S. Womersley identified species
collected near Perth and Freemantle. Prof. D. A. Herbert permitted use of the
laboratory facilities of the Department of Botany at the University of Queensland
at Brisbane. Prof. B. J. Grieve provided a laboratory in the Department of Botany
at the University of Western Australia at Nedlands (Perth). Dr. G. F. Humphrey
arranged for the use of a laboratory at the Fisheries Station of the Commonwealth
Scientific Industrial and Research Organization at Cronulla (Sydney). Mr. J.
Madgwick assembled equipment at Cronulla. Mrs. Harold H. Strain contributed
indispensable laboratory assistance.
SUMMARY
1 . The chloroplast pigments of twelve species of siphonalean green algae native
to the marine waters of Australia were isolated by chromatography.
2. All these siphonalean species but one contained the same pigments found
in the siphonalean Chlorophyceae of the Northern Hemisphere.
3. Caulcrpa filijonnis lacked the siphonaxanthin and siphonein associated with
the chlorophylls and carotenoids in the other Siphonales, but it contained a pre-
ponderance of a-carotene relative to /3-carotene as did all the other Siphonales.
370 MAN'' >LD JI. STRAIN
4. The.M' oliM-natioiis indicate ;liat the Siphonales arc significantly different
from the other screen al-ac, hut they are more closely related to the C'hlorophyceac
than to any other al^al ^roiip.
5. The pigment distrihution supports the classification of the Siphonales with
the Chlorophyceae. the Meterosiphonales (' Yaucheriaeeae) and the Heterotrichales
(Tribonematareae i with the Xanthophyceae or Heterokontae.
LITERATURE CITED
ALLEN, M. 1!., I.. Fun-;.-, T. \V. (iooinvix AND D. M. THOMAS, 1964. The carotenoids of alga-:
pigments from >ome cryptomonads, a heterokont and some Rhodophyseae. /. Gen.
Microbiol, 34: J5" 267. '
FKUIMANN, ].. l"4o. Sur I'heU'niplaMe de certaines Siphonales et leur classification. (". l\.
FRITSCH, F. !"., 1 ( '35 ( Reprinted 1%1). The Structure and Reproduction of the Algae. Vol. I,
pp. xvii i 7 () 1. _45 tigs.. University Press, Cambridge.
MIXVA. 'I'.. Y. IKIKI AND T. SIV.UKI, 1960 (Pub. 1961). Mannan and xylan as essential cell
\vall coiistitncnls of some siphonous green algae. Colloq. Intern. Centre Nat'l. Rcch.
Set.. ( Paris) No. 103: 135-144 (English).
SMITH, G. M.. 1955. Cryptogamic Botany. Vol. I, pp. vii + 546, 311 figs., McGraw-Hill Book
Co., Xeu York.
STRAIN, H. H., 1951. Manual of Phycology, pp. 243-262. Smith, G. M., ed., Chronica Botanica
Co., pp. xi + 375, 48 figs., Waltham, Mass.
STRAIN, II. H., 1958. Chloroplast Pigments and Chromatographic Analysis. 32nd Annual
Priestley Lectures, pp. 180, 41 figs., Pennsylvania State University, University Park.
STRAIN, H. H., 1964. Chloroplast pigments of various plants. Argonne National Laboratory
Reviews, Vol. 1, No. 3, 6-7.
TAYLOR, W. R., 1960. Marine Algae of the Eastern Tropical and Subtropical Coasts of the
Americas. Pp. xi + 870, 14 photos, 80 pi., University of Michigan Press, Ann Arbor.
WOMK.RSI.KV. H. R. S., 1959. The marine algae of Australia. Baton. Rcr., 25: 545-614.
A MICROSPORIDIAN INFECTION OF THE DIGESTIVE TRACT
THE WINTER FLOUNDER, PSEUDOPLEURONECTES
AMERICANUS x
HORACE W. STUNKARD AND FRED E. LUX
The American Museum of Natural History, Nezv York, N. Y ., and The U. S. Deft, of the Interior,
Bureau of Commercial Fisheries, Biological Laboratory. U'oods Hole, Massachusetts
Linton (1901) reported sporozoan infections in two small winter flounders,
Pseudopleuronectes auiericanns. taken from Katama Bay, Martha's Vineyard, and
examined at Woods Hole on August 28, 1900. His account, although brief, is
adequate for recognition of the parasite and reads (p. 487), "The walls of tin-
intestine of one throughout almost the entire length and of the other for a short
distance were completely covered with sporocysts. The cysts were irregular where
crowded together ; where not crowded together, which was in but few places, they
were elliptical or spherical, of various sizes, but comparatively few reaching 1 mm.
in diameter and none much exceeding that. Spores oblong-ovate about 0.003 mm.
in length and 0.0015 mm. in diameter. Intestine where affected was chalky-white
in color." The accompanying figure shows a "Piece of intestine of Pseudopleuro-
nectes aniericanits, serous coat covered with cysts due to sporosperms (sic} ." There
was no attempt at identification of the parasite, but Linton recognized that it was
distinct from another, reported in the same publication (pp. 438 and 439), found
in the muscles of the back and sides of the herring, Cliipea harentjus, and the alewife,
Pomolobus pseudoharengus,
The latter species was identified as a myxosporidian and almost one-half of the
young fishes were infected. Tyzzer (1900) reported the discovery and prevalence
of this infection in young P. pseudoharengus; Auerbach (1910) assigned the species
to the genus Chloroiny.rwn Mingazzini, 1890; and Halm (1917) proposed the
specific name, Chloromyxum clupeidae. The allocation to Chloromyxum was based
on the spore, which has a quadrilateral apical end and bears four polar capsules.
Kudo (1920, p. 94) examined the slides prepared by Tyzzer, and others made from
'various species of fishes, and reported the infection in Clupea harengus, Pomolobus
pseudoharengus, P. acstivalis, P. mediocris, Brevoortia tyrannus, Stenotomus
chrysops, and Tautogolabrus adspcrsus, taken at Woods Hole. The parasites from
the muscles of these fishes were regarded as specifically identical and referred to
Chloromyxum, clupeidae Hahn, 1917.
A third sporozoan was reported by Linton (1901; p. 455) from the liver
nf the butterfish, Poronotus triacanthus (syn. Rhombus triacanthus}. The cyst was
white and globular, about 1.5 mm. in diameter; when compressed it liberated im-
mense numbers of spores, often aggregated in globular or oblong clusters, as large
as 0.02 mm. in diameter. The spores were short and thick, with bluntly rounded
ends, about 0.0025 mm. in length and a little less than that in breadth and thickness.
1 This investigation was supported in part by NSF-GB-3606, Continuation of G23561.
371
372 HORACE \\ . STUNKARD AND FRED E. LUX
The parasite is obviously a microsporidian and Woodcock (1904; p. 54) regarded it
as a species of Pleistophora.
A fourth sporozoan was uhservt'd by Linton (1901 ; p. 433) : an enormous
number of small elliptical bodies. 14 by 6 microns, were found in the intestinal
contents of a sting-ray, Dasvafis coitronra. Since the spores were in the lumen
of the gut, it is apparent that they were ingested in food and were parasitic in some
animal other than the ray.
The parasites reported by Linton from the wall of the digestive tract of P.
aincricanus are similar to and possibly identical with others reported about the
>ame time from flat-fishes of Europe. Hagenmiiller (1899) observed the infection
in at least one-half ("IS fois sur 30") of the small fishes, Fle.vns passer Moreau
(== Plcnroncctt's passer] from littoral pools in the area of Endoume, Bouches-du-
Rhone, France. The parasite was named Nosenm stephani in honor of M. Pierre
Stephan. who first found the cysts and called them to the attention of the author.
He wrote (p. S37, "Cette Myxosporidie appartient au genre Glitgca Thelohan.
aujourd'hui !\'<>scniu ; elle infeste, sous forme d'infiltration diffuse ou de kystes, les
parois du tube digestif . . . L'infiltration diffuse represente plus particulierement
un mode de pullulation endogene, tandis que les kystes assurent la dissemination du
parasite a 1'exterieur. Kystes et amas d'infiltration s'observent depuis la partie
superieure de 1'oesophage jusqu' a 1'extremete du rectum, loges dans les tissus ou
.simpk>ment reconverts par le peritoine. II n'existe ni amas ni kystes dans le
parenchyme d'aucun organe, rein, rate, foie, coeur, etc. Cependant, sous le peritoine
a la surface du foie et dans les replis peritoneaux ou cheminent des vaisseaux, les
kystes sont assez nombreux; j'en ai trouve jusque sur le conduit choledoque pres
de son abouchement avec 1'intestin. Dans la paroi intestinale, les kystes siegent
dans les couches musculaires et surtout dans la couche conjonctive. J'en ai vu
jusque dans la charpente conjonctive des replis de la muqueuse et des villosites.
mais jamais, non plus que d'infiltration diffuse, dans la couche epitheliale de
1'intestin.
"Ce.s k \\stes apparaissent a 1'oeil nu comme de petits grains d'un blanc de lait.
ovoides ou plus rarement spheriques, ne depassant guere 1 mm. en diametre.
n'atteignant meme pour la plupart que quelques dixiemes de millimetre, ou moins
encore." I fagenmuller discussed the formation of the cyst and concluded that the
membranous wall is produced by the host as a reaction to invasion by the parasite.
A similar and presumably identical species was reported by Johnstone (1901 i
from the plaice, 1'lcitronectes platessa, taken in the Irish Sea along the coast of
Lancashire, fhe author recognized the parasite as a protozoan, probably a sporo-
zoan, but further identification was not attempted. The infection was limited to
the digestive tract and the intestine, from the pylorus to the anus, was thickened and
superficially looked like a ripe ovary. The external surface was studded with small.
round, white, opaque bodies; the internal surface was disposed in irregular, longi-
tudinal folds, covered with projecting, round white bodies; the lumen was reduced
and the inucosa often lost ; and the wall measured 3 to 4 mm. in thickness. The
cysts were about 0.60 mm. in diameter, with a capsule composed of an outer cuticular
and an inner fibrous layer. The spores were oval with a maximum length of 0.005
mm. Figures portrayed ti i<>pearance of the intestine, the structure of the
wall, and the form of the spores.
MICROSPORIDIOSIS IN WINTER FLOUNDER
Woodcock (1904) described a second infection in the digestive tract of the
plaice, P. platessa, taken near Plymouth, England, and discussed the Myxosr
in flatfishes. For him, the Myxosporidia Biitschli, 1881 were "characterized
by the fact that reproduction by spores goes on throughout the growing or 'trophic'
period, and (b) by the complicated process of spore-formation and the natur.
the spores." The group was, thus, the equivalent of the Neosporidia Schaudinn,
1900 and the Cnidosporidia Doflein, 1901, and included the Microsporidia Balbiana,
1882. Woodcock reviewed the papers by Hagenmuller, Linton, and Johnstone;
he noted that the infection reported by Johnstone was a "ripe, well-matured one,"
extensively distributed, whereas the infection he studied was only a slight and
limited one, from a fish that superficially was quite healthy in appearance. In this
specimen, the gut showed little oval patches, 1.00 mm. in diameter, usually
projecting slightly on the outer, coelomic side together with other small pyriform
appendages, 1.50 to 2.00 mm. in length, attached to the gut by the narrow end.
These enlargements were all on the side of the gut to which the mesentery was
attached, and in which the blood vessels ran. The functional activity of the
intestine was not impaired ; the mucosa was intact and normal in appearance.
Woodcock compared sections made from the lightly infected intestine with others
made from material sent by Dr. Johnstone. He discussed endogenous multi-
plication ("multiplicative reproduction" of Doflein) in young forms, the spread
of the infection into neighboring tissue by diffuse infiltration and the formation
of cysts and pseudocysts. He stated (p. 57), "Quite probably 'multiplicative
reproduction' is, here, simply a separation of the pansporoblast rudiments, as
daughter individuals. Indeed the whole nature of diffuse infiltration in Glugea
seems to me to support this idea. There is no question of the individual parasites
attaining size, still less of any continuity of a protoplasmic mass ramifying in and
between host's tissue-cells. It is far rather a cell-infection, visible, when ripe, as
separate clumps of spores, each formed from, and representing, one pansporoblast,
and either still surrounded by a hypertrophied host-cell, or else free, but only
owing to the latter's breakdown." The infections reported by Hagenmuller,
Linton and Johnstone were referred to the same species, here designated as
Glugea stephani (Hagenmuller, 1899) Woodcock, 1904.
Stempell (1904) studied the development of Nosctna auoinala Moniez. 1887, a
species from the connective tissue in subcutaneous loci and in the gut-wall, liver,
and gonads of the fresh-water stickleback, Gastcrostcus aculeatus. This species
had been transferred by Gurley (1893) to the genus, Glugea Thelohan, 1891.
Stempell noted that recent investigations had disclosed a series of protozoan species
in which the life-cycles consisted of a limited period of vegetative, asexual
multiplication, after which different, "ycartete" forms appear, whose further
multiplication is conditional on the conjugation or copulation of two individuals.
After citing essentials of these investigations he stated (p. 31), "Bedenkt mann
dagegen, dass die allgemeinen Grundziige der Entwicklung, soweit sie sich feststellen
liessen, in alien Fallen dieselben sind, so darf man wohl mit Recht schliessen, dass
samtliche beschriebenen Parasitenformen der Spezies Nosema anomalum Monz.
angehoren. In der Tat, ein treffender Name fiir eine so variable Spezies !" Ac-
cordingly, he returned the species, anoniala, to the genus Nosema. In this species
he reported growth of the protoplasmic masses with rapid, asexual multiplication of
374 HORACE \\ STUNKARD AND FRED E. LUX
nuclei, followed l.\ tin- differentiation of .-poronts, the admitted progenitors of the
>e\ual generation. His accounl re; ds (p. 33), "Wir sehen, wie in der enzystierten
Parasitenma.vse /unachst ein \Vachsunn des Protoplasmas und eine starke Vermeh-
rung der Kerne ;inf rein ungeschlechtlichem Wege erfolgt, wie sich aber schon
sehr bald ans dieser vegetal Parasitenmasse die als Vorfahren der Geschlechts-
generation auf/ufassendcn Sporonten differenzieren. Nur dadurch unterscheiden
sich die vorliegenden Mic oridien und so viele phanozyste Myxosporidien von
der Mehrzahl des anderen Sporozoen, dass diese Geschlechtgeneration durch
endogene Knospung im Korper der vegetativen Individuen entsteht."
Weissenberg (1911) reported that about 2% of the smelt. Osnicrus cpcrlaints.
taken from sources near Berlin and from inlets of the Baltic Sea, were infected
with a microsporidian parasite, similar to but distinct from Gluyca anomala, which
he described as a new species, Glugca hcrtwici'i. He observed no difference in the
infections of fishes from fresh and salt water. In a second paper, Weissenberg
(1913) reviewed the work of Stempell (1904) and other authors on microsporidian
species and reported on the life-cycles of G. anotnala and G. heiiu'igi. Since the
time of Pasteur it has been known that certain microsporidians invade the ovary
and penetrate the ova, with hereditary transmission of infection. Stempell de-
scribed Mich infected ova, but Weissenberg (1913) declared the evidence was not
convincing. To test the matter, he raised sticklebacks, Gastcrosteits aculeatus,
from eggs. When the yolk-sacs were resorbed he fed small copepoda and daphnids
but the fishes did not grow 7 . Fine emulsions of spores were added to the water,
but no infection resulted. With other fishes raised in aquaria but fed plankton
with an abundance of plant and animal food, growth was good and two young
-licklebacks daily were fed plankton mixed with an emulsion of spores. Three
weeks after the beginning of the experiment, one of the fishes had a G I it yea-cyst,
300 microns in diameter, on the wall of the throat. This result demonstrates that
a fish raised in the laboratory became infected and provides information on the rate
of cyst formation. Weissenberg concluded (p. 157),"Wenngleich die oben dargeleg-
ten I'.efunde beziiglich der Entwicklungsprozesse von GliKjca anoinala in zahl-
reichen I'nnkten von den Ergebnissen der Voruntersucher abweichen, so gelange
id i doch y.n der gleichen Gesamtauffassung wie die alteren Autoren, insbesonder
Stempell Audi nach meinen Befunden koinmt Ghujca ein grosser eigener Plas-
makorper mil xablreichen vegetativen Kernen zu. Die ganze Cyste gehort zum
Protozoon. Wirtszellen oder hypertrophische Wirtskerne sind am Cystenaufbau
nicht beteiligt." In a subsequent paper, Weissenberg (1921) discussed the prob-
l ( 'm whether 01 nol the large Plasmakorper, with its large vesicular nuclei, is de-
rived from host tissue or is of protozoan origin. After presenting new evidence
he concluded (p. 420) 'An der Wirtsgewebsableitung des Plasmakorpers und
der blaschenformigei i rne der G'litf/ca-Cysten kann nun nicht mehr gezweifelt
werden. Aufgabe kunfii ''orschung wird es sein, die Art der phagocytenartigen
verstreut im Bind ret< nden I'ischzellen, die somit den Alutterboden fiir
die Glitfii'it Cysten al i genauer zu eruieren."
Meanu-liile, Mavor i L915 . reported that about 50% of tin- I'sciuluplcnn>ncflcs
americanus examined In the er and autumn of 1910 at Woods Hole, Mass.,
were infected with (,'/n ,///. Me also found Osincnis inonia.v at Woods
Hole frequently infected with a ui!cro>])oridian, apparently G. stcplidiii. These find-
MICROSPORIDIOSIS IN WINTER FLOUNDi
ings are in marked contrast to others made in the summer of 1912, \\hen no infec
tions were found on examination of 82 P. americanus and 22 0. mordax ta'
the region of St. Andrews, New Brunswick. Kudo (1924) suspected thai: the
parasite of 0. mordax was G luge a hertwigi.
Schrader (1921) found 28% to 53% of the smelts, 0. mordax from lakes in New
Hampshire, and 1.5% to 16% of those from the coast of Maine were infected with a
species which he identified as 0. hertwigi Weissenberg, 1911. The intestine was
the primary seat of infection although cysts were present in the liver and gonads.
The cysts ranged in size from microscopic to 3 mm. in diameter, but were similar
in size in each fish. The highest incidence of infection was in immature fishes,
the majority of infected fish die while immature. Unlike G. ano/mila, G. hertwigi
was regarded as specific for smelts since other fishes in the same area were not in-
fected. Furthermore, connective tissue and muscles were not infected, which ap-
parently served to distinguish G. hertwigi from G. anomala.
Reichenow (1929) described Glugca stephani from infections of Pleuronectes
liuianda at Helgoland. He found white cysts, 0.5 mm. in diameter, in the sub-
mucosa of the intestine and reported (p. 1099), "Die Parasiten bilden zuerst In-
fektionsherde in der Darmwand, die von Hagenmuller und Woodcock als Zustand
diffuser Infiltration (vgl. S. 1046) bezeichnet warden. Die Parasiten haben
jedoch keinen interzellularen Sitz, vielmehr befallen sie im Laufe ihrer Vermehrung
zahllose benachbarte Zellen (entweder Bindegewebszellen oder vielleicht Leuko-
cyten, die sich an der Infektionsstelle ansammeln). Um den ganzen Herd herum
bildet sich eine dicke Bindegewebskapsel, und so entstehen die Cysten, deren Inhalt
also in diesem Falle nicht durch eine einzige Riesenzelle, sondern durch viele infi-
zierte Zellen dargestellt wird. Die fertig ausgebildeten Cysten findet man haupt-
sachlich von ungeheuren Sporenmassen erfiillt, zwischen denen verstreut Zell-
und Kernreste vorkommen. Eine paarige Anlage der Sporen, welche die Stellung
dieser Art zu der Gattung Glugca begriinden wiirde, ist von keinem der Untersucher
beschrieben worden. Ich babe in dem von mir beobachteten Falle eher den Ein-
druck gewonnen, dass die Sporen einzeln entstehen, so dass die Art also zu Nosema
zu rechnen w r are. Doch wird sich dies erst bei Beobachtung friiherer Infektions-
stadien, die iibersichtlichere Bilder geben, entscheiden lassen. In meinem Falle,
in dem die Cysten dicht gedrankt in der Darmwand sassen, war die Schleimhaut auf
weite Strecken vollig abgestossen; es ist daher zu vermuten, dass die Fische an
starken Infektionen zugrunde gehen."
Recent accounts have added little information on microsporidian infections of
fishes. Bond (1938) identified cysts found in sections of the stomach of Fundulus
het.eroditus taken in Chesapeake Bay as G. hertwigi, but the determination may
not be correct. Fantham et al. (1941) described an infection in the hindgut of a
specimen of O. mordax taken from Lake Edward, Quebec, and listed the parasite as
G. hertwigi var. canadensis. Also, they reported G. stephani in the submucosa
of the intestine of P. americanus and Limanda jerruginea, taken near Halifax, Nova
Scotia; L. jerruginea was recognized as a new host of the parasite. Haley (1952)
described a severe epidemic of microsporidiosis in 0. mordax in Loon Pond, Gil-
manton, New Hampshire, and 16 of 20 O. mordax from the Oyster River taken at
376 HORACE W. STVXK.WD AND FRED E. LUX
Durham, N. II.. were infected i<\ m -pecies, which he identified as G.
hertwigi.
The Micnporidia arc chiell\ sites of invertebrates, especially crustaceans
and insect-. The classilicatii Microsporidia or Microspirida is based pri-
marily upon the form and strucum of the spores and to a lesser degree upon differ-
ences in the details of sport/genesis. The parasites of P. americanus belong to the
family Nosematidae, characterized by small, oval or ovate spores, each with one
IK ilar filament. The genera are distinguished by the number of spores that are
produced by each sporont. According to Poisson (1953), in Nosema each sporont
develops into a sporoblast and produces a single spore; in other genera the numbers
of spores produced are: Glugea Thelohan, 1891 and Perczia Leger et Duboseq.
1909, two .-pores; in Gitrleya Doflein, 1898 and Pyrotheca Hesse, 1935, four
sporoblasts and four spores; but in Stempellia Leger et Hesse, 1910, the numbers
of spores produced are: Glugea Thelohan, 1891 and Pcrczia Leger et Duboscq,
number varies from 8 to 32; and in Plistophora Gurley, 1893, each sporont (pan-
.-poroblast) produces more than 16 spores. It is generally believed that the micro-
.-poridia are narrowly host-specific. According to Poisson (1953) some 40 spe-
cies in the genera Plistophora, Glugea, and Noscina occur in fishes and one species,
Glugea danilewsky, occurs in the muscles and connective tissue of Rana jnsca,
liiuys orbicularis, Natrix natri.v and other hosts. If this determination is correct,
the distribution of G. danilewsky belies the opinion that species of Glugea are host-
specific.
The life-history of the Microsporidia, as conceived by Debaisieux (1928), com-
prises two distinct phases : a multiplicative stage, schizogony, beginning with the
liberation of the uninucleate or binucleate sporoplasm or planont from the spore
and its entry into a host-cell, and sporogony, a spore-forming stage, in which spo-
ronts produce sporoblasts that give rise to resistant spores, the infective agents that
serve for dispersal of the parasite and the infection of new hosts. According to
Kudo (1924, p. 34), "No intermediate host animals have up to date been found
for Microsporidia. The infection of a new host animal takes place when the latter
ingests spores of a specific microsporidian capable of germinating in its gut." A
similar statement was made by Dogiel, Petrushevski and Polyanski (1961) but no
reference to experimental evidence was cited.
It is generally agreed that the life-cycle of the microsporidian involves sexual
phenomena but there is wide disagreement concerning the location in the cycle where
meio-is and > jamy occur. Meiotic phenomena have never been observed in the
Microsporidia and j amy has been reported by autogamy of nuclei in the sporo-
plasm before or after n from the spore, and also by nuclear fusion preceding
sporont formation. Writing on sexual phenomena in Protozoa, Hall (1953, p. 80)
stated, "A reduction of the chromosomes to the haploid number may occur in ga-
metogenesis (yin dosis), in an early division of the zygote (sygotic inciosis),
or in one of the pregami ;ons in conjugation (conjugated uieiosis). The type
of meiosis varies in different Protozoa. Available data indicate that the Heli-
ozoida, Foraminifera, Cnido>poridia, and Ciliophora are diploid throughout most
of the life-cycle.' An opposite opinion was stated by Cheissin and Poljansky
(1963, p. 343), "In the life-cycles of the Sporozoa the alternation of sexual process
and sporogony or that of sexual process, sporogony and repeated asexual multipli-
MICROSPORIDIOSIS IN WINTER FLOUNDER
cation by means of schizogony occurs. All the developmental stage
haploid ones because the meiosis usually appears during the process of sp;
followed by formation of sporozoites." The statement by the Russian an:
parently is based on the situation in the malarial parasites, but the Micro^
are distinct from the Haemosporidia and the life-cycles may be quite different.
deed. Kudo (1944, p. 50) reporting on the life-cycle of Noscina votabilis Kudo.
1939, stated, "Schizogony is by binary fission. No sexual process has been observed
in the development of Nosema notabilis."
The small size of the amoeboid stages and of the spores, usually less than 4
microns in length, together with the inability to obtain early stages by controlled
experimental infecti
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0
Research Papers: Design Automation
# A Constraint Satisfaction Algorithm for the Generalized Inverse Phase Stability ProblemOPEN ACCESS
[+] Author and Article Information
Edgar Galvan
Design Systems Laboratory,
Department of Mechanical Engineering,
Texas A&M University,
College Station, TX 77843
e-mail: [email protected]
Richard J. Malak
Associate Professor
Design Systems Laboratory,
Department of Mechanical Engineering,
Texas A&M University,
College Station, TX 77843
e-mail: [email protected]
Sean Gibbons
Computational Materials Science Lab,
Department of Materials Science
and Engineering,
Texas A&M University,
College Station, TX 77843
e-mail: [email protected]
Raymundo Arroyave
Associate Professor
Computational Materials Science Lab,
Department of Materials Science
and Engineering,
Texas A&M University,
College Station, TX 77843
e-mail: [email protected]
1Corresponding author.
Contributed by the Design Automation Committee of ASME for publication in the JOURNAL OF MECHANICAL DESIGN. Manuscript received March 21, 2016; final manuscript received July 25, 2016; published online October 5, 2016. Assoc. Editor: Carolyn Seepersad.
J. Mech. Des 139(1), 011401 (Oct 05, 2016) (11 pages) Paper No: MD-16-1227; doi: 10.1115/1.4034581 History: Received March 21, 2016; Revised July 25, 2016
## Abstract
Researchers have used the (calculation of phase diagram) CALPHAD method to solve the forward phase stability problem of mapping from specific thermodynamic conditions (material composition, temperature, pressure, etc.) to the associated phase constitution. Recently, optimization has been used to solve the inverse problem: mapping specific phase constitutions to the thermodynamic conditions that give rise to them. These pointwise results, however, are of limited value since they do not provide information about the forces driving the point to equilibrium. In this paper, we investigate the problem of mapping a desirable region in the phase constitution space to corresponding regions in the space of thermodynamic conditions. We term this problem the generalized inverse phase stability problem (GIPSP) and model the problem as a continuous constraint satisfaction problem (CCSP). In this paper, we propose a new CCSP algorithm tailored for the GIPSP. We investigate the performance of the algorithm on Fe–Ti binary alloy system using ThermoCalc with the TCFE7 database against a related algorithm. The algorithm is able to generate solutions for this problem with high performance.
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## Introduction
The designers of novel materials require an understanding of phase stability in order to assess the feasibility of a material and how it changes during processing. The calculation of phase diagram (CALPHAD) method has enabled researchers to develop databases that contain pertinent thermodynamic information on specific alloys and associated phases [1]. In this method, the thermodynamics of phases are described through mathematical models fitted to experimental data.
Many calphad software packages developed to date are well-suited for solving the forward phase stability problem: calculating the phase stability state of a multicomponent, multiphase system given a set of thermodynamic conditions (processing conditions such as composition, temperature, and pressure). However, because design is inherently an inverse process, we are interested instead in the inverse problem: determining the thermodynamic conditions that give rise to a desired phase stability state.
Previous investigations have used optimization algorithms in the context of inverse phase stability problems to search for extremal points in multidimensional phase stability maps [28]. These extremal points are locations along a direction corresponding to a single thermodynamic degree-of-freedom, e.g., the lowest liquidus temperature. This class of problems typically has a single solution and can be formulated straightforwardly as Display Formula
(1)$Minimizex∈Ω f(x)$
where the set $Ω⊂RN$ is the feasible region in the decision space (thermodynamic conditions), and f is a function (e.g., a CALPHAD model) from $RN$ to $R$ that maps thermodynamic conditions to the thermodynamic degree-of-freedom of interest. The optimization problem in Eq. (1) can be solved using conventional techniques. In Ref. [4], mesh-adaptive direct search (MADS) [9] algorithms are used to find extrema in phase stability. More recently, the Arroyave group has used genetic algorithms (GAs) to solve similar problems [6].
Although the location of extremal points, or any isolated point(s) in the phase constitution space, is sometimes of interest to material scientists [10,11], more generalized knowledge is desirable for the materials discovery and design process. Specifically, we are interested in identifying the region or set in the design space that gives rise to a desirable range of thermodynamic conditions, we refer to this problem as the generalized inverse phase stability problem (GIPSP).
For example, a designer may want to know what thermodynamic conditions (a set of designs) result in the presence of σ phase in steels, since any amount of σ phase is undesirable due to its embrittling effects (as little as 3 wt.% reduces impact toughness by more than half [12]) and its drastic deterioration of the stability against corrosion. A compact representation of this set would be useful to material designers as a constraint on the search space that is easy to evaluate. In cases when uncertainty in the appropriate CALPHAD model is high, materials designers may be interested in finding a set of potentially desirable solutions that they can refine and prune through experimentation. In general, materials designers are interested in identifying the set of all the thermodynamic conditions that could produce the set of arbitrary phase constitutions. In the language of engineering design, materials designers would like to apply set-based approach [13] to the materials discovery process.
In the context of set-based design, Shahan and Seepersad suggested the use of Bayesian network classifiers to model the satisfactory region [14]. In Ref. [15], the technique is extended to multilevel design problems (multilevel models are those that are hierarchically nested) and applied to materials design. An extension is developed by Rosen [16] that enables the incorporation of process knowledge. However, the focus of these works is on the design methodology concerning multiscale design rather than an efficient algorithm approach for approximating the satisfactory set, which is the aim of this paper.
We model the GIPSP as a continuous constraint satisfaction problem (CCSP) [17], a type of constraint satisfaction problem (CSP) where all the variable domains are continuous real intervals. The GIPSP is to map specific regions in multidimensional phase constitution spaces to ranges of values of thermodynamic conditions space. The solution set to this problem is ranges of values (enclosures) rather than discrete points. The GIPSP is particularly challenging because the search space is highly nonlinear and discontinuous, the CALPHAD model is a black-box since its details are not available, and the problems of interest may be multidimensional (>10).
Typical algorithmic approaches for CCSPs (Fig. 1), such as those based on interval arithmetic [18], require accessible analytical problem formulations. However, the GIPSP involves a nonanalytical CALPHAD model. Methods such as design of experiments (DOE) [19] or inductive design exploration (IDEM) [20,21] are not tractable for high-dimensional problems since they sample the search space. Another approach is to use adaptive sampling schemes to replace the expensive to evaluate constraint with a surrogate model [2225]. However, these approaches have difficulty representing discontinuities in the search space and suffer from the curse of dimensionality [26]. To address this limitation, Basudhar and Missoum developed the explicit design space decomposition (EDSD) method. The EDSD method relies on a support vector machine (SVM) classifier to model the design space constraint boundary, rather than approximate the constraint function. The EDSD method has been shown to accurately model the constraint boundary on several test problems within only a fewer iterations.
However as we will show that the SVM technique used in EDSD has difficulty representing the solution to a typical GIPSP. In a GIPSP, it is undesirable to densely sample the unsatisfactory region since it comprises the vast majority of the space. In the case where the samples are imbalanced (many more from one class than another), the SVM will be unreliable in the undersampled region. In cases with imbalanced sampling, the support vector domain description (SVDD) technique has been shown to be more appropriate [27]. In this paper, we present an algorithm that instead relies on the support vector domain description (SVDD) [27] classifier, which leads to improvements in both computation time and solution quality of the GIPSP.
## Generalized Inverse Phase Stability Problem as a Continuous Constraint Satisfaction Problem
We define the GIPSP using standard notation in the CSP literature [28] as a triple Display Formula
(2)$P=(X,D,C)$
where $X=(x1,x2,…,xn)$ is a n-tuple of variables defined in the thermodynamic conditions space, and $D=I1,×,I2,×⋯×,In$ is the Cartesian product of the corresponding domains, where Ii is a real interval for $i=1,2,…,n$. The set of constraints that must be satisfied is denoted as $C=(C1,C2,…,Ct)$, which is a t-tuple of constraints. Each constraint Cj is a pair Rj, Sj, where Rj is a relation on the variables in $Sj=scope(Cj)$. The relation Rj defines the consistent value combinations. Specifically, in the context of the GIPSP, Rj is an inequality or equality in terms of the function mapping between thermodynamic conditions and phase constitutions (i.e., constraints defined on the CALPHAD model). The set $Sj⊂X$ is an unordered k-tuple of distinct variables, where k is the arity of Rj. In other words, Sj is simply the tuple of variables that participate in the constraint Rj.
A solution is a n-tuple $A=(a1,a2,…,an)$, where $A∈D$ and each Cj is satisfied, in which Rj holds on the projection of $A$ onto the scope, i.e., Sj. The problem is to find the set of all the solutions to the problem, denoted $sol(P)$. In the GIPSP, the user defines each constraint Cj in the phase constitution space. For example, one may be interested in the thermodynamic conditions $X=(x1,x2)$ that produce materials consisting of between 40 wt.% and 60 wt.% of a specific phase. This constraint is expressed as $C≡0.4≤f(X)≤0.6$, where $f(·)$ maps thermodynamic conditions to the phase composition of interest. The CCSP is expressed as Display Formula
(3)$X=(x1,x2)D=(x1lb,x1ub)×(x2lb,x2ub)C≡0.4≤f(X)≤0.6$
where the superscripts lb and ub denote the variable lower and upper bounds, respectively.
Since mapping from the thermodynamic conditions space to the phase constitution space is highly complex, discontinuous, and nonanalytical, satisfying the user-defined constraints C is nontrivial. In the motivating problem, we are interested in the set of all the solutions, $sol(P)$, to the CCSP where all the variable domains are continuous real intervals and all the numeric relations are equalities and/or inequalities. The constraints are, in general, highly nonlinear.
## Related Work
###### Existing CSP Algorithms.
Classical methods for solving CSPs such as backtracking [29], iterative broadening search [30], and limited discrepancy search [31] are intended for problems with discrete domains and are not efficient for solving CCSPs. To apply these to a CCSP, one must discretize the variable space to an enumerable set [32]. Such an approach would be intractable for most GIPSPs because of the high-dimensional (often n > 10) [33] of many materials design scenarios. Most techniques developed specifically for solving CCSPs are based on interval arithmetic, branch and bound, or the root inclusion test. In one of the first examples of set-based design, Ward proposed the use of interval arithmetic to search for the feasible set of designs efficiently [18]. Subsequently, this work was extended to more general set-based representations [34]. Hu et al. proposed a method that uses generalized interval to solve for the feasible set [35,36]. The NUMERICA [37] modeling language in particular guarantees correctness, completeness, and certainty. Devanathan and Ramani presented a polytope-based method, where the constraints are transformed into ternary constraints [38]. Then, the so-called consistency method is used to prune the search space. These techniques require an analytical or closed-form expression to determine whether a subsection of the search space contains feasible solution [28,39,40]. Since the CALPHAD model is a “black-box” in the sense that the details are not accessible, methods that rely on interval arithmetic or constraint decomposition cannot be used for the GIPSP.
###### Design of Experiments.
Identifying the feasible set (solving a CSP) is a key challenge in many set-based design methods. Design of experiments (DOE) can be used to test the constraint model at a set of finite points in the design domain. A limitation is that the points will not lie on the boundary of the constraints. The inductive design exploration method (IDEM) addresses this limitation [20,21]. The IDEM consists of discrete point evaluations (discrete sampling) of the design process, performing inductive, top-down feasible space exploration based on metamodels. The aim is to obtain a robust solution with respect to model uncertainty. To approximate the constraint boundary, the design space is sampled using a typical DOE. The true constraint boundary will lie between the satisfactory and unsatisfactory discrete points. A root-finding technique is used to find the location of the boundary between these points. The constraint is then represented as a set of boundary points and points inside the feasible space. Although this method generates points on the boundary of the constraint, it does little to reduce the computational burden of the initial DOE, which suffers from the curse of dimensionality.
###### Constraint Modeling.
Constraint satisfaction has also been addressed in the reliability-based design optimization (RBDO), where the aim is to avoid the performance failure region. Consider a product with random system parameters $X$ and a performance function g(x), where the product fails if g(x) < 0. The reliability of the product is defined as Display Formula
(4)$R=P(g(X)≤0)=∫g(x)>0⋯∫fX(x)dx$
where $fX(x)$ is the joint probability density function of all the random parameters. This integral may be approximated using Monte Carlo simulation (MCS), but this approach can be computationally expensive when a large number of samples are required or the constraints are expensive to evaluate. A principle focus in RBDO is the efficient approximation of the solutions to the constraint g(x). An approach common in the literature is to replace the expensive to evaluate constraint g(x), with an inexpensive surrogate model generated from sampled data. The most straightforward methods sample the space globally, which becomes prohibitively expensive at high dimensionality. An approach for reducing the number of samples required to construct the surrogate model is adaptive sampling. Adaptive sampling approaches incrementally improve the surrogate model by sampling points that most effectively improve the model [2224]. These approaches attempt to efficiently “train” a surrogate model over the entire search space. However, to approximate Eq. (2), it is only necessary to know where the constraint is satisfied. This insight led to the efficient global reliability analysis (EGRA) method. In EGRA, samples are generated by maximizing the expected feasibility function, which provides an indication of how well the true value of the response is expected to satisfy the constraint [25]. Several other criteria can be found in the literature [4143].
As argued by Basudhar and Missoum, the principle limitations surrogate-based approaches are response discontinuities and the curse of dimensionality [26]. The discontinuities in the search space are problematic for gradient-based techniques. To address this limitation, they proposed a method referred to as explicit design space decomposition (EDSD), which does not approximate the response of the limit state function, instead constructs an explicit constraint boundary around the design variables [44]. Thus, the EDSD method is unaffected by discontinuities and other irregularities in the search space. The EDSD method relies on the use of support vector machines to construct an explicit boundary of the constraint in the design space. Support vector machines (SVMs) are a machine-learning technique for supervised learning associated with two-class classification. That is, given a set of training examples, each example is marked as belonging to one of the two classes. The SVM uses the training examples to build a model that assigns new (unobserved) examples to one of the categories. The SVM is initially trained on a sample of points. Then, an adaptive strategy is used to generate points that likely lie on the constraint boundary.
The EDSD method has been shown to approximate the limit state function successfully for a number of test problems [45]. However, because the EDSD method relies on the SVM method, its performance deteriorates when an SVM is not an appropriate representation of the boundary. The SVM treats evaluated samples as a two-class data set: feasible and infeasible observations. For a good performance, the SVM technique requires both classes to be well sampled [46,47].
This limitation is significant in the GIPSP, where, intuitively, few process parameter combinations will yield a desirable material. Thus, the solution to a GIPSP is typically small relative to the search space. In this scenario, it is undesirable to evenly sample both satisfactory and unsatisfactory classes, especially for high-dimensional problems where a balances sampling of the entire search space may be computationally expensive. If to reduce computational expense, we undersample the unsatisfactory space, the resulting SVM will be unreliable in the undersampled unsatisfactory space and will tend to have high rates of false positives. In cases with imbalanced sampling, the support vector domain description (SVDD) technique has been shown to be more appropriate [27]. Whereas the SVM scheme is a two-class classifier, the SVDD scheme is a one-class classifier intended to address the case where the training data are mainly from a single category.
## Support Vector Domain Description
The support vector domain description (SVDD) [27] is used to approximate the solution based on observed data. The SVDD method is a nonprobabilistic machine-learning technique for predicting the boundary of a data set in an Euclidean space. The SVDD method bears close resemblance to support vector machines (SVMs) [48,49]. The principal difference being that SVDD is a one-class classifier while SVMs are two-class classifiers. For a detailed description of the SVDD, see Refs. [27] and [50]. Under the SVDD method, one finds the minimum radius hypersphere that contains a set of training data. Let xi denote a vector in the design variable space $X$ —the input space. Given n data points, $X={xi|i=1,2,…,n}$, the minimum radius hypersphere containing every data point with centroid a and radius rDisplay Formula
(5)$Minimizer,ar2+c∑iξisubject to‖xi−a‖2≤r2+ξi, ξi≥0 ∀i$
where ξi are the slack variables that allow for the possibility of outliers in the training set. The parameter c defines how to tradeoff between Hampshire volume and errors. Any point at a distance equal to or less than r from the hypersphere center is inside of the domain description. However, because a hypersphere is typically a poor representation of the domain, a kernel function is used to nonlinearly remap the training data into a higher-dimensional feature space where a hypersphere is a good model. Through the so-called kernel trick, the data points are mapped to the feature space, without computing the mapping explicitly. The result is an implicit mapping to a feature space of unknown, possible infinite, dimensionality. There are several valid kernel functions common in the literature [51]. The proposed algorithm uses the Gaussian kernel function Display Formula
(6)$KG(xi,xj)=Φ(xi)·Φ(xj)=e−q‖xi−xj‖2$
where Φ(⋅) is the nonlinear mapping from the data space to the feature space. The q parameter determines how “tightly” or “loosely” the domain description is fit around the training data. The constraint in Eq. (5) then becomes Display Formula
(7)
where b is the centroid of the feature space hypersphere. Rewriting in terms of the kernel function, the Wolfe dual problem can be developed from Eq. (7) as Display Formula
(8)
For a detailed description of the method for formulating the Wolfe dual problem see Ref. [52]. For each data point, xi for i = 1, 2,…, n, there are three possible classifications:
1. (1)It is inside the hypersphere, which is indicated by βi = 0.
2. (2)It is on the boundary of the hypersphere, which is indicated by 0 < βi < c.
3. (3)It is an outlier outside of the hypersphere, which is indicated by βi = c.
Data on the boundary of the hypersphere are called support vectors (SVs) and are essential to the domain description representation. The outliers are not part of the domain description. Choosing c ≥ 1 yields no outliers since $∑iβ1=1$ and 0 < βi < ci, and therefore, . The squared distance of the feature space image of a point, z, to the centroid of the hypersphere is Display Formula
(9)$r2(z)=K(z,z)−2∑iβiK(xi,z)−∑i,jβiβjK(xi,xj)$
A new test point, z, is inside the domain description if the distance from the feature space image of test point to the hypersphere centroid is less than the radius of the hypersphere. The expression for classification, Eq. (9), is a simple algebraic expression that is fast to evaluate. In fact for the Gaussian kernel function, the first term is equal to 1, and the last term can be precomputed since it is independent of z.
A final consideration is the SVDD method that is able to tighten the description by using negative examples—labeled outliers. The aim in this case is to find the minimum radius hypersphere that includes the positive examples (target-data) while excluding the negative examples (outlier-data). Consider that target-data are enumerated by indices i, j and the outlier-data by l, m. Further, the target-data are labeled yi = 1 and outlier-data are yl = −1. The search problem becomes Display Formula
(10)$Minimizer,a r2+c1∑iξi+c2∑lξlsubject to‖xi−b‖2≤r2+ξi‖xl−b‖2≥r2+ξlξi,ξl≥0 ∀i,l$
Again, by the method of Lagrange multipliers, we can obtain Display Formula
(11)$L=∑iβ′iK(xi,xj)−∑lβ′lK(xl,xl)−∑i,jβ′iβ′jK(xi,xj)+2∑l,jβ′lβ′jK(xl,xj)−∑l,mβ′lβ′mK(xl,xm)$
where $β′i=yiβi$ (the index i again enumerates both target and outlier-data). See Ref. [46] for a detailed exposition of the SVDD method with negative examples.
To prevent weighting variables with large magnitudes more than those with lower ones in this comparison, the training data are centralizing (scale all data to a −1 to 1 range), which improves the SVDD model. An important benefit of the SVDD method is that it can be constructed incrementally and decrementally [53]. This allows for a relatively inexpensive update procedure to be used when new members are added or removed from the SVDD. Figure 2 is an illustration of the SVDD method on a two-dimensional data set in the thermodynamic conditions space.
To underscore the difference in performance between the SVM and SVDD classifiers, we develop two test problems where one class (the satisfactory region) is (a) large and (b) small relative to the domain, see Fig. 3. In each case, we created a training data set with 50 satisfactory and 50 unsatisfactory random examples. In example (a) where the regions are proportional, the samples are relatively balanced, while in (b), they are imbalanced (the unsatisfactory region is undersampled).
We use both examples to train an SVM and SVDD classification model. We used the SVM algorithm in MATLAB's Statistics and Machine Learning Toolbox [54], and SVDD model in DD_Tools [55] developed in the Pattern Recognition Laboratory at Delft University of Technology, Delft, Netherlands. The results are illustrated in Fig. 3. In scenario (a), the SVM model outperforms the SVDD model. This is expected since the SVDD tends to generate conservative model; recall that the SVDD finds the minimum radius hypersphere around the target-data. In contrast, in scenario (b) where the data are not balanced, the SVM classifier results in a significant overestimation. In the latter case, the more conservative SVDD scheme has better performance. This basic insight motivates an adaptive sampling scheme based on SVDD rather than SVM for the GIPSP.
## Proposed Algorithm
Our aim is to develop an adaptive sampling scheme based on the SVDD technique for approximating the constraint boundary. The basic idea of the proposed algorithm is that the true boundary of the satisfactory region is approximately parallel to our current best guess. In the proposed algorithm, we search along the direction perpendicular to the SVDD boundary (our current best guess) for a point on the true boundary of the satisfactory region using a root-finding method. Figure 4 is an illustration of this idea. An initial point is selected along the SVDD boundary along with an initial step size. The initial step size is selected using information from the SVDD. If the end point is outside of the satisfactory region, a root-finding method is used to find a point on the boundary. The proposed method is described in detail in Algorithm 1. We assume that the designer has available small number of designs that satisfy the specified phase state properties, i.e., the constraints. The initial samples may be obtained from prior equilibrium experimental data or found using conventional optimization techniques. In the case studies presented in this paper, we use random sampling to generate n data points $X={xi|i=1,2,…,n}$ in the design variable space. The randomly generated samples are assigned labels $Y={yi|i=1,2,…,n}$, such that y = 1 or y = −1 according to whether or not they satisfy the constraints, respectively. The set of indices Ib is initialized to the empty set.
The samples and their corresponding labels are used to generate an approximation of the solution set using the SVDD technique. We use $M$ to denote this classification model. The model parameters q and c are selected such that the so-called F1 measure is minimized, see Ref. [56] for details. Ultimately, our goal is to search along the direction perpendicular to the boundary of $M$. First, we must select a suitable starting point for this search. An intuitive initial point is some support vector (SV), since the SVs are those samples that lie on the boundary of the domain description. However, in practice, there tends to be few SVs relative to the size of training data. In only a few iterations, all the SVs of the SVDD model may lie on the true boundary of the satisfactory region but our approximation may still be poor. Instead, the algorithm selects the point on the boundary of $M$ that maximizes the distance to any point on the true boundary. Let the indices corresponding to the samples that lie on the boundary of the true solutions be Ib. The initial sample xa is found such that Display Formula
(12)$Maximizet,xa tsubject to t≤||xj−xa|| ∀j∈Ib∑iβ′iKG(xi,xa)=r$
where t is a dummy variable, $X={xi,i=1,…,n}$ are the training data, and $r=∑iβ′iKG(xi,xk)$ for any $k∈SV⊂{1,…,n}$, the set of support vectors. To prevent the case where the algorithm attempts to “reuse” a previous initial point, Ib should also include the indices corresponding to previous initial sample points. Because the Gaussian Kernel is an inexpensive function, Eq. (12) is fast to evaluate. It is important to note that the initial point xa is not guaranteed to be satisfactory. This can occur when the SVDD modeling parameter q (see Sec. 4) is set too “loose.” As a result, it is necessary to evaluate the initial point xa against the constraints $C$ to determine its label, denoted as ya.
Next, the algorithm takes an initial step in the direction perpendicular to the boundary of $M$ at xa, which is the direction that maximizes the distance to the feature space centroid Display Formula
(13)$d=∂r2(z)∂z=−2∑iβ′i∂K(xi,z)∂zi$
which is the gradient of Eq. (9). In the case of the Gaussian kernel Display Formula
(14)$∂KG(xi,z)∂z=2(xi−z)eq||z−xi||2$
It is desirable to choose a step size γ large enough to cross the boundary of the satisfactory region. If the label ya = 1, we should step outside of $M$ to find additional satisfactory points, “growing” the model. On the other hand, ya = −1 indicates that $M$ is optimistic, and we should step inside of $M$ to find additional unsatisfactory points, “tightening” the model. Choosing an appropriate initial step size has a significant impact on algorithmic performance. One consideration is that the initial step should not take us too far from the current SVDD, $M$. To address this, we limit the step size to $γ≤minγ{r2(xa−γ*d)}/2$, which limits the step size according to the size and shape of $M$ along the direction of d. Another consideration is that during search, we should expect disjointed “clusters” in $M$. In this situation, we should take a step size that is at the feature space midpoint of the clusters. If disjointed clusters exist along the direction d, their feature space midpoint is at $γ=maxγ{r2(x0+γ*d)}$. We use these concepts to determine the initial step size according to Algorithm 2.
The next step is to search for a boundary point using line search (spec. bisection search), see Algorithm 3 for a description. If the initial step xb did not cross the boundary of the true solution, that is, ya = yb, the bisection search algorithm terminates and returns the training set X and Y containing only the samples xa and xb. Else, the algorithm uses bisection search to reduce the size of the interval between xa and xb until it is less than some user-defined error tolerance, ε.
Finally, the training set X and Y are updated to contain the samples points that were evaluated against the constraints, i.e., points for which a label y was generated. The set of indices Ib is also updated to contain indices corresponding to the true boundary points found (within tolerance ε). This process is repeated user-defined N times, a termination rather than a convergence criteria. It would be possible to develop a convergence criteria based on the change in $M$ at each generation; this is left as future work. Without a convergence criteria, analysis of computation complexity is less meaningful but still worth considering. In the case of the GIPSP, evaluating a design against constraints (ClassLabel in Algorithms 1–3) is the elementary operation, all others are lower order. Let ε0 and ε be the maximum interval length and error tolerance for the bisection search, respectively. The time complexity is $O(N log2(ε0/ε))$, where N is the number of iterations to be performed.
Algorithm 1 SVDD-Based Sampling Algorithm
1. procedure SVDDsample($X,D,C$)
2. $X,n←RandomSample(X,D)$
3. $Y←ClassLabel(X,C)$
4. $Ib←∅$
5. for$i←1$ to Ndo
6. $M←$train SVDD model with X, Y ▷ Eq. (8)
7. $xa,ya←Select initial point$ ▷ Eq. (12)
8. $xb,yb←TakeInitStep(M,C,xa,ya)$
9. $Xi,Yi,Ii←BisectionSearch(xa,ya,xb,yb,C)$
10. $X,Y←(X,Xi),(Y,Yi)$ ▷ Concatenate
11. $Ib←(Ib,Ii+n)$
12. $n←n+Ii$
13. return$M$
Algorithm 2 Take Initial Step
1. procedure TakeInitStep($M,C,xa,ya$)
2. $d←$gradient of $r(xa)$ ▷ Eq. (13)
3. r2 from Eq. (9)
4.
5. $γ←min{γmax,γmin}$
6. ifya = −1 then ▷ If xa is not satisfactory
7. $γ←−γ$
8.
9. $yb←ClassLabel(xb,C)$
10. return xb, yb
Algorithm 3 Bisection Search
1. procedure BisectionSearch($xa,ya,xb,yb,C$)
2. $X,Y←(xb,xa),(yb,ya)$ ▷ Concatenate
3. $I←2$ ▷ Counter
4. if$ya≠yb$then
5. while$||xa−xb||≤ε$do
6. $xc←xb+12(xa−xb)$ ▷ Midpoint
7. $yc←ClassLabel(xc,C)$
8. $X,Y←(X,xc),(Y,yc)$
9. ifya = ycthen ▷ Update interval
10. $xa,ya←xc,yc$
11. else
12. $xb,yb←xc,yc$
13. $I←I+1$ ▷ Update counter
14. returnX, Y, I
## Case Study
###### Test Problems.
We evaluate the performance of the proposed algorithm on Fe–Ti binary alloy system, see phase diagram in Fig. 5. Given the thermodynamic conditions, the phase compositions are computed using ThermoCalc with the TCFE7 database. Recall that the GIPSP is the triple $P=(X,D,C)$. The thermodynamic conditions (design variables) are $X=(x1,x2,x3)$, where x1 is the mass percent of Ti, x2 is the mass percent of Fe, and x3 is the temperature (Kelvin). The search domain $D$ is defined as
The CALPHAD model, denoted $f=(f1(X),f2(X),…,f5(X)),$ maps the thermodynamic conditions to the volume fraction of BCC, FCC, HCP, Laves, and liquid phase, respectively. We consider two different scenarios (test cases). In the first test case, the materials designer wishes to find all the thermodynamic conditions that result in volume fraction of Laves and liquid phase between 0.25 and 0.75. For this test case, the constraints $C$ are Display Formula
(16)
In the second test case, the materials designer wishes to find all thermodynamic conditions that result in volume fraction FCC greater than 0.05. For this test case, the constrain C is Display Formula
(17)$f2(X)≥0.05$
The solutions to these search problems are illustrated in Fig. 5, the shaded regions. The test cases were selected to investigate the performance of the algorithm when the solution is nonconvex (test case 1), and small relative to the search space (test case 2). Notice that for test case 1, interactions at the eutectic cause irregularities in the solution set. Although these irregularities will not agree with experimental data, they complicate the search space and can give better insight into the performance.
###### Results and Analysis.
The proposed algorithm is motivated by the GIPSP, which is typically multidimensional and features response discontinuities that are problematic for gradient-based search techniques. To evaluate the performance of the proposed algorithm on this class of problem, we compare to EDSD, which is intended for constraint satisfaction problems with similar characteristics. The principal difference is that the proposed algorithm is intended to address the case where the satisfactory region is undersampled (as we expect is the case with most GIPSPs).
In both algorithms, performance is dependent on the initial training data. To account for this, each case was tested for 30 trials with random initial training data. For each trial (in either test case), we randomly sampled the domain $D$ to find ten feasible and ten infeasible sites. The same data are used to initialize each algorithm. These initializing functions are not counted toward the overall function count of either algorithm.
Since both EDSD and the GIPSP algorithm use binary classifiers, we evaluate solution quality using the precision and recall metrics commonly used in pattern recognition [57]. We generate a set X of 106 random samples in the design space domain $D$ defined by Eq. (15). We then find $X′⊂X$, the subset that satisfies the user-specified conditions, $C$, in Eq. (16) for test case 1 and Eq. (17) for test case 2. Next, we find $X″⊂X$ the subset that is classified as belonging to the satisfactory set, according to the classifier (SVM for EDSD and SVDD for the GIPSP algorithm). We compute the true positives, true negatives, false positives, and false negatives as PositiveNegativeTrue$Ntp=|X′∪X″|$$Ntn=|X∖X′∪X∖X″|$False$Nfp=|X′∪X∖X″|$$Nfn=|X∖X′∪X″|$
where $|·|$ denotes cardinality. The terms positive and negative refer to the classifier's prediction and true and false refer to how that prediction corresponds to the actual classification. Taking these terms into account, we can compute the precision and recall measures as Display Formula
(18)$Precision=NtpNtp+NfpRecall=NtpNtp+Nfn$
If we consider the positive classifier predictions to be the “solution set,” precision can be interpreted as the probability that a randomly selected alternative in the solution set will be truly satisfactory. Recall is the probability that a randomly selected true solution will be represented in the solution set. Thus, higher values of precision and recall are preferred. We also consider the misclassification rate of the classifier as a performance metric Display Formula
(19)$Misclassification rate=Nfp+NfnNfp+Nfn+Ntp+Ntn$
Lower values of misclassification rate are preferred, however, one must be cautions when interpreting this measure. For example, in a case where the satisfactory region is very small, classifying the entire region as “unsatisfactory” will have a low misclassification rate.
We calculate each performance metric at several intervals for each algorithm. We report the mean values and 95% confidence interval of 30 trials for both test cases in Figs. 6 and 7, respectively. In test case 1, the GIPSP algorithm produces a higher precision approximation for any given number of function evaluations. This is not unexpected since the SVDD is more conservative than the SVM technique. Both algorithms converge to a similar measure of recall and a low level of misclassification error. In test case 2, the GIPSP algorithm generates high-precision solutions and converges to a solution with high recall and low misclassification rate. However, the precision of the EDSD solution does not improve significantly after 100 iterations, and the recall measure becomes worse. Further, the solution quality is highly variable across each iteration, resulting in large confidence intervals.
For illustrative purposes, we include Figs. 8 and 9, which depict the progression of each algorithm at the (a) 100, (b) 250, and (c) 400, function evaluations for each test case. The shaded region represents the true solution to each CCSP found through an exhaustive search. An attempt was made to illustrate trials that are representative of the mean values in 6 and 7. However, we should not that in both test cases (but especially for test case 2), the performance of the EDSD algorithm varied significantly. Therefore, no illustration of a single result can be truly illustrative of the typical results. Taking these limitations into account, the illustrations still provide some valuable insight into the performance of each algorithm.
As can be seen in Fig. 8, the GIPSP algorithm maintains high precision during its progression, including few false positives. The EDSD, on the other hand, produces more optimistic estimations of the satisfactory region, initially. The higher precision of the GIPSP solution is reflected in the “tighter” classifier boundary. The precision at (c) 400 function evaluations for the EDSD algorithm is considerably higher than the med.
Note that Fig. 9 is focused on the solution space (which is quite small), the search space for this test problem is defined by Eq. (15) and depicted in Fig. 5. Test case 2 is intended to highlight the limitations of EDSD method on problems where the satisfactory region is small relative to the search space. In such cases, the SVM technique used in EDSD tends to overestimate the satisfactory region. In Fig. 9, the overestimation occurs near the true solution (shaded portions), however, this is not always the case. Figure 10 is an illustration of the results from another trial of the EDSD algorithm in test case 2.
## Discussion and Summary
In this paper, we have presented a novel algorithm for approximating all the solutions to a CCSP with nonisolated solution where the satisfactory region is small relative to the search space. The algorithm uses the SVDD technique combined with a sampling strategy to gradually develop the solution. The motivation for the algorithm is the general inverse phase stability problem of mapping user-specified regions in multidimensional phase constitution space to ranges in values of thermodynamic conditions, which we term the GIPSP. In the GIPSP, one class (the satisfactory region) is small relative to the other (unsatisfactory region). For scalability, it is desirable to undersample the unsatisfactory region, since it comprises the vast majority of the space. This motivates the use of the SVDD method in the algorithm since it is able to more accurately (in terms of precision and recall) model scenarios with imbalanced training data.
We investigated the performance of the algorithm on Fe–Ti binary alloy system using ThermoCalc with the TCFE7 database. Using this system, we formulated two test cases. In the first test case, the solution set is nonconvex; in the second, the solution set is small relative to the search space. We compare the performance of the GIPSP algorithm to the EDSD algorithm, which uses a related classification scheme, namely, SVM. The performance of each algorithm on the test problems was measured as the precision, recall, and misclassification rate. In both test problems, the GIPSP algorithm is able to converge to a solution with high precision and recall. The EDSD algorithm, however, had significant difficulty in approximating the solution to test case 2. This is likely the result of the limitations of the SVM technique used in EDSD. The SVM technique is known to underperform in cases with imbalanced training data sets. In test case 2, the satisfactory region is small relative to the search space, resulting in an imbalanced training data set.
Future work should also investigate the performance of the algorithm on problems of higher dimensionality that are more representative of real-world materials design problems.
## Acknowledgements
This work was supported by the National Science Foundation and the Air Force under Grant No. EFRI-1240483. The authors would like to thank Paul Mason from ThermoCalc for providing critical thermodynamic data, which made this research possible.
## Nomenclature
• a =
centroid of hypersphere
• b =
centroid of feature space hypersphere
• c =
SVDD parameter
• Cj =
constraint
• d =
direction perpendicular to SVDD boundary
• f =
thermodynamic conditions → phase constitution
• $fX$ =
random parameter joint pdf
• g =
performance function
• Ib =
set of indices corresponding to boundary points
• Ii =
real interval
• K =
kernel function
• n =
number of data points
• N =
dimensionality of thermodynamic conditions space
• Nfn =
number of false negatives
• Nfp =
number of false positives
• Ntn =
number of true negatives
• Ntp =
number of true positives
• q =
Gaussian kernel parameter
• r =
• R =
reliability
• Rj =
relation on the variables involved in constraint Cj
• Sj =
scope of the constraint Cj
• SV =
set of support vectors
• t =
dummy variable
• X =
training data set
• xi =
design variable
• xi =
a vector in the design variable space $X$
• Y =
set of training data labels
• yi =
training data label
• z =
test point
• βi =
Lagrangian multiplier
• γ =
step size
• ε =
error tolerance
• ε0 =
maximum interval length
• ξi =
slack variable
• Φ =
data space → feature space
• $A$ =
n-tuple solution to $P$
• $C$ =
t-tuple of constraints
• $D$ =
search space
• $M$ =
classification model
• $P$ =
constraint satisfaction problem
• $X$ =
n-tuple of variables
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Hou, J. S. , Guo, J. T. , Zhou, L. Z. , and Ye, H. Q. , 2006, “ Sigma Phase Formation and Its Effect on Mechanical Properties in the Corrosion-Resistant Superalloy K44,” Z. Metallkd./Mater. Res. Adv. Tech., 97(2), pp. 174–181.
Ward, A. C. , Liker, J. K. , Cristiano, J. J. , and Sobek, D. K., II , 1995, “ The Second Toyota Paradox: How Delaying Decisions Can Make Better Cars Faster,” MIT Sloan Manage. Rev., Spring, pp. 43–61.
Shahan, D. W. , and Seepersad, C. C. , 2012, “ Bayesian Network Classifiers for Set-Based Collaborative Design,” ASME J. Mech. Des., 134(7), p. 071001.
Matthews, J. , Klatt, T. , Morris, C. , Seepersad, C. C. , Haberman, M. , and Shahan, D. , 2016, “ Hierarchical Design of Negative Stiffness Metamaterials Using a Bayesian Network Classifier,” ASME J. Mech. Des., 138(4), p. 041404.
Rosen, D. W. , 2015, “ A Set-Based Design Method for Material-Geometry Structures by Design Space Mapping,” ASME Paper No. DETC2015-46760.
Cruz, J. , 2005, “ Constraint Reasoning for Differential Models,” 2005 Conference on Constraint Reasoning for Differential Models, IOS Press, pp. 1–216.
Ward, A. C. , 1989, “ A Theory of Quantitative Inference Applied to a Mechanical Design Compiler,” Ph.D., MIT, Cambridge, MA.
Montgomery, D. C. , 2008, Design and Analysis of Experiments, Wiley, New York.
Choi, H.-J. , Mcdowell, D. L. , Allen, J. K. , and Mistree, F. , 2008, “ An Inductive Design Exploration Method for Hierarchical Systems Design Under Uncertainty,” Eng. Optim., 40(4), pp. 287–307.
Choi, H. , McDowell, D. L. , Allen, J. K. , Rosen, D. , and Mistree, F. , 2008, “ An Inductive Design Exploration Method for Robust Multiscale Materials Design,” ASME J. Mech. Des., 130(3), p. 031402.
Wang, C. , Duan, Q. , Gong, W. , Ye, A. , Di, Z. , and Miao, C. , 2014, “ An Evaluation of Adaptive Surrogate Modeling Based Optimization With Two Benchmark Problems,” Environ. Modell. Software, 60, pp. 167–179.
Huang, D. , Allen, T. , Notz, W. , and Miller, R. , 2006, “ Sequential Kriging Optimization Using Multiple-Fidelity Evaluations,” Struct. Multidiscip. Optim., 32(5), pp. 369–382.
Wang, G. G. , Wang, L. , and Shan, S. , 2005, “ Reliability Assessment Using Discriminative Sampling and Metamodeling,” SAE Technical Paper No. 2005-01-0349.
Bichon, B. J. , Eldred, M. S. , Swiler, L. P. , Mahadevan, S. , and McFarland, J. M. , 2008, “ Efficient Global Reliability Analysis for Nonlinear Implicit Performance Functions,” AIAA J., 46(10), pp. 2459–2468.
Basudhar, A. , and Missoum, S. , 2008, “ Adaptive Explicit Decision Functions for Probabilistic Design and Optimization Using Support Vector Machines,” Comput. Struct., 86(19), pp. 1904–1917.
Tax, D. M. , and Duin, R. P. , 1999, “ Support Vector Domain Description,” Pattern Recognit. Lett., 20(11–13), pp. 1191–1199.
Tsang, E. , 1993, Foundations of Constraint Satisfaction, Vol. 289, Academic Press, London.
Golomb, S. W. , and Baumert, L. D. , 1965, “ Backtrack Programming,” JACM, 12(4), pp. 516–524.
Ginsberg, M. L. , and Harvey, W. D. , 1992, “ Iterative Broadening,” Artif. Intell., 55(2), pp. 367–383.
Harvey, W. D. , and Ginsberg, M. L. , 1995, “ Limited Discrepancy Search,” IJCAI, 1, pp. 607–615.
Sam-Haroud, D. , and Faltings, B. , 1996, “ Consistency Techniques for Continuous Constraints,” Constraints, 1(1), pp. 85–118.
Cruz, J. , and Barahona, P. , 2003, “ Constraint Satisfaction Differential Problems,” Principles and Practice of Constraint Programming–CP 2003, Springer, Berlin, pp. 259–273.
Finch, W. W. , and Ward, A. C. , 1997, “ A Set-Based System for Eliminating Infeasible Designs in Engineering Problems Dominated by Uncertainty,” Proceedings of the ASME Design Engineering Technical Conferences, Sacramento, CA, Paper No. DETC97/DTM-3886.
Hu, J. , Aminzadeh, M. , and Wang, Y. , 2014, “ Searching Feasible Design Space by Solving Quantified Constraint Satisfaction Problems,” ASME J. Mech. Des., 136(3), p. 031002.
Hu, J. , Wang, Y. , Cheng, A. , and Zhong, Z. , 2015, “ Sensitivity Analysis in Quantified Interval Constraint Satisfaction Problems,” ASME J. Mech. Des., 137(4), p. 041701.
Van Hentenryck, P. , Michel, L. , and Deville, Y. , 1997, Numerica: A Modeling Language for Global Optimization, MIT Press, Cambridge, MA.
Devanathan, S. , and Ramani, K. , 2010, “ Creating Polytope Representations of Design Spaces for Visual Exploration Using Consistency Techniques,” ASME J. Mech. Des., 132(8), p. 081011.
Neumaier, A. , 2004, “ Complete Search in Continuous Global Optimization and Constraint Satisfaction,” Acta Numer., 13(1), pp. 271–369.
Kearfott, R. B. , 1987, “ Abstract Generalized Bisection and a Cost Bound,” Math. Comput., 49(179), pp. 187–202.
Sasena, M. J. , 2002, “ Flexibility and Efficiency Enhancements for Constrained Global Design Optimization With Kriging Approximations,” Ph.D. thesis, University of Michigan, Ann Arbor, MI.
Schonlau, M. , 1998, Computer Experiments and Global Optimization, University of Waterloo, Waterloo, ON, Canada.
Au, S. , and Beck, J. L. , 1999, “ A New Adaptive Importance Sampling Scheme for Reliability Calculations,” Struct. Saf., 21(2), pp. 135–158.
Basudhar, A. , and Missoum, S. , 2010, “ An Improved Adaptive Sampling Scheme for the Construction of Explicit Boundaries,” Struct. Multidiscip. Optim., 42(4), pp. 517–529.
Basudhar, A. , 2011, Computational Optimal Design and Uncertainty Quantification of Complex Systems Using Explicit Decision Boundaries, The University of Arizona, Tucson, AZ.
Tax, D. M. , and Duin, R. P. , 2004, “ Support Vector Data Description,” Mach. Learn., 54(1), pp. 45–66.
Le, T. , Tran, D. , Ma, W. , and Sharma, D. , 2012, “ A Unified Model for Support Vector Machine and Support Vector Data Description,” 2012 International Joint Conference on Neural Networks (IJCNN), IEEE, pp. 1–8.
Vapnik, V. , 1995, The Nature of Statistical Learning Theory, Springer, New York.
Scholkopf, B. , and Smola, J. A. , 2002, Learning With Kernels, MIT Press, Cambridge, MA.
Malak, J. R. J. , and Paredis, C. J. J. , 2010, “ Using Support Vector Machines to Formalize the Valid Input Domain of Predictive Models in Systems Design Problems,” ASME J. Mech. Des., 132(10), p. 101001.
Scholkopf, B. , Williamson, R. , Smola, A. , Shawe-Taylor, J. , and Platt, J. , 1999, “ Support Vector Method for Novelty Detection,” Advances in Neural Information Processing Systems, MIT Press, pp. 582–588.
Wolfe, P. , 1961, “ A Duality Theorem for Nonlinear Programming,” Q. Appl. Math., 19(3), pp. 239–244.
Cauwenberghs, G. , and Poggio, T. , 2001, “ Incremental and Decremental Support Vector Machine Learning,” Neural Information Processing Systems, 13, pp. 409–415.
MathWorks, 1998, “ Mathworks User's Guide,” Vol. 5, MathWorks Inc., Natick, MA, p. 333.
Tax, D. , 2005, “ Ddtools: The Data Description Toolbox for Matlab,” Delft University of Technology, Delft, Netherlands.
Tax, D. M. , 2015, “ Ddtools: The Data Description Toolbox for Matlab, Version 2.1.2,” Delft University of Technology, Delft, Netherlands.
Powers, D. M. , 2011, “ Evaluation: From Precision, Recall and F-Measure to ROC, Informedness, Markedness and Correlation,” J. Mach. Learn. Technol., 2(1), pp. 37–63.
Topics: Stability , Algorithms
View article in PDF format.
## References
Saunders, N. , and Miodownik, A. P. , 1998, CALPHAD (Calculation of Phase Diagrams): A Comprehensive Guide, Vol. 1, Elsevier, Amsterdam, The Netherlands.
Bale, C. , Chartrand, P. , Degterov, S. , Eriksson, G. , Hack, K. , Ben Mahfoud, R. , Melançon, J. , Pelton, A. , and Petersen, S. , 2002, “ Factsage Thermochemical Software and Databases,” Calphad, 26(2), pp. 189–228.
Gheribi, A. E. , Robelin, C. , Digabel, S. L. , Audet, C. , and Pelton, A. D. , 2011, “ Calculating All Local Minima on Liquidus Surfaces Using the Factsage Software and Databases and the Mesh Adaptive Direct Search Algorithm,” J. Chem. Thermodyn., 43(9), pp. 1323–1330.
Gheribi, A. E. , Audet, C. , Le Digabel, S. , Bélisle, E. , Bale, C. , and Pelton, A. , 2012, “ Calculating Optimal Conditions for Alloy and Process Design Using Thermodynamic and Property Databases, the Factsage Software and the Mesh Adaptive Direct Search Algorithm,” Calphad, 36, pp. 135–143.
Zhu, R. , Li, S. , Karaman, I. , Arroyave, R. , Niendorf, T. , and Maier, H. J. , 2012, “ Multi-Phase Microstructure Design of a Low-Alloy Trip-Assisted Steel Through a Combined Computational and Experimental Methodology,” Acta Mater., 60(6–7), pp. 3022–3033.
Zhu, R. , Li, S. , Karaman, I. , Arroyave, R. , Niendorf, T. , and Maier, H. J. , 2012, “ Multi-Phase Microstructure Design of a Low-Alloy Trip-Assisted Steel Through a Combined Computational and Experimental Methodology,” Acta Mater. 60(6–7), pp. 3022–3033.
Li, S. , Zhu, R. , Karaman, I. , and Arroyave, R. , 2012, “ Thermodynamic Analysis of Two-Stage Heat Treatment in Trip Steels,” Acta Mater., 60(17), pp. 6120–6139.
Li, S. , Zhu, R. , Karaman, I. , and Arroyave, R. , 2012, “ Thermodynamic Analysis of Two-Stage Heat Treatment in TRIP Steels,” Acta Mater. 60(17), pp. 6120–6130.
Audet, C. , and Dennis, J., Jr. , 2006, “ Mesh Adaptive Direct Search Algorithms for Constrained Optimization,” SIAM J. Optim., 17(1), pp. 188–217.
Gomez-Acebo, T. , Sarasola, M. , and Castro, F. , 2003, “ Systematic Search of Low Melting Point Alloys in the Fe-Cr-Mn-Mo-C System,” Calphad, 27(3), pp. 325–334.
Du, H. , and Morral, J. , 1997, “ Prediction of the Lowest Melting Point Eutectic in the Fe-Cr-Mo-V-C System,” J. Alloys Compd., 247(1), pp. 122–127.
Hou, J. S. , Guo, J. T. , Zhou, L. Z. , and Ye, H. Q. , 2006, “ Sigma Phase Formation and Its Effect on Mechanical Properties in the Corrosion-Resistant Superalloy K44,” Z. Metallkd./Mater. Res. Adv. Tech., 97(2), pp. 174–181.
Ward, A. C. , Liker, J. K. , Cristiano, J. J. , and Sobek, D. K., II , 1995, “ The Second Toyota Paradox: How Delaying Decisions Can Make Better Cars Faster,” MIT Sloan Manage. Rev., Spring, pp. 43–61.
Shahan, D. W. , and Seepersad, C. C. , 2012, “ Bayesian Network Classifiers for Set-Based Collaborative Design,” ASME J. Mech. Des., 134(7), p. 071001.
Matthews, J. , Klatt, T. , Morris, C. , Seepersad, C. C. , Haberman, M. , and Shahan, D. , 2016, “ Hierarchical Design of Negative Stiffness Metamaterials Using a Bayesian Network Classifier,” ASME J. Mech. Des., 138(4), p. 041404.
Rosen, D. W. , 2015, “ A Set-Based Design Method for Material-Geometry Structures by Design Space Mapping,” ASME Paper No. DETC2015-46760.
Cruz, J. , 2005, “ Constraint Reasoning for Differential Models,” 2005 Conference on Constraint Reasoning for Differential Models, IOS Press, pp. 1–216.
Ward, A. C. , 1989, “ A Theory of Quantitative Inference Applied to a Mechanical Design Compiler,” Ph.D., MIT, Cambridge, MA.
Montgomery, D. C. , 2008, Design and Analysis of Experiments, Wiley, New York.
Choi, H.-J. , Mcdowell, D. L. , Allen, J. K. , and Mistree, F. , 2008, “ An Inductive Design Exploration Method for Hierarchical Systems Design Under Uncertainty,” Eng. Optim., 40(4), pp. 287–307.
Choi, H. , McDowell, D. L. , Allen, J. K. , Rosen, D. , and Mistree, F. , 2008, “ An Inductive Design Exploration Method for Robust Multiscale Materials Design,” ASME J. Mech. Des., 130(3), p. 031402.
Wang, C. , Duan, Q. , Gong, W. , Ye, A. , Di, Z. , and Miao, C. , 2014, “ An Evaluation of Adaptive Surrogate Modeling Based Optimization With Two Benchmark Problems,” Environ. Modell. Software, 60, pp. 167–179.
Huang, D. , Allen, T. , Notz, W. , and Miller, R. , 2006, “ Sequential Kriging Optimization Using Multiple-Fidelity Evaluations,” Struct. Multidiscip. Optim., 32(5), pp. 369–382.
Wang, G. G. , Wang, L. , and Shan, S. , 2005, “ Reliability Assessment Using Discriminative Sampling and Metamodeling,” SAE Technical Paper No. 2005-01-0349.
Bichon, B. J. , Eldred, M. S. , Swiler, L. P. , Mahadevan, S. , and McFarland, J. M. , 2008, “ Efficient Global Reliability Analysis for Nonlinear Implicit Performance Functions,” AIAA J., 46(10), pp. 2459–2468.
Basudhar, A. , and Missoum, S. , 2008, “ Adaptive Explicit Decision Functions for Probabilistic Design and Optimization Using Support Vector Machines,” Comput. Struct., 86(19), pp. 1904–1917.
Tax, D. M. , and Duin, R. P. , 1999, “ Support Vector Domain Description,” Pattern Recognit. Lett., 20(11–13), pp. 1191–1199.
Tsang, E. , 1993, Foundations of Constraint Satisfaction, Vol. 289, Academic Press, London.
Golomb, S. W. , and Baumert, L. D. , 1965, “ Backtrack Programming,” JACM, 12(4), pp. 516–524.
Ginsberg, M. L. , and Harvey, W. D. , 1992, “ Iterative Broadening,” Artif. Intell., 55(2), pp. 367–383.
Harvey, W. D. , and Ginsberg, M. L. , 1995, “ Limited Discrepancy Search,” IJCAI, 1, pp. 607–615.
Sam-Haroud, D. , and Faltings, B. , 1996, “ Consistency Techniques for Continuous Constraints,” Constraints, 1(1), pp. 85–118.
Cruz, J. , and Barahona, P. , 2003, “ Constraint Satisfaction Differential Problems,” Principles and Practice of Constraint Programming–CP 2003, Springer, Berlin, pp. 259–273.
Finch, W. W. , and Ward, A. C. , 1997, “ A Set-Based System for Eliminating Infeasible Designs in Engineering Problems Dominated by Uncertainty,” Proceedings of the ASME Design Engineering Technical Conferences, Sacramento, CA, Paper No. DETC97/DTM-3886.
Hu, J. , Aminzadeh, M. , and Wang, Y. , 2014, “ Searching Feasible Design Space by Solving Quantified Constraint Satisfaction Problems,” ASME J. Mech. Des., 136(3), p. 031002.
Hu, J. , Wang, Y. , Cheng, A. , and Zhong, Z. , 2015, “ Sensitivity Analysis in Quantified Interval Constraint Satisfaction Problems,” ASME J. Mech. Des., 137(4), p. 041701.
Van Hentenryck, P. , Michel, L. , and Deville, Y. , 1997, Numerica: A Modeling Language for Global Optimization, MIT Press, Cambridge, MA.
Devanathan, S. , and Ramani, K. , 2010, “ Creating Polytope Representations of Design Spaces for Visual Exploration Using Consistency Techniques,” ASME J. Mech. Des., 132(8), p. 081011.
Neumaier, A. , 2004, “ Complete Search in Continuous Global Optimization and Constraint Satisfaction,” Acta Numer., 13(1), pp. 271–369.
Kearfott, R. B. , 1987, “ Abstract Generalized Bisection and a Cost Bound,” Math. Comput., 49(179), pp. 187–202.
Sasena, M. J. , 2002, “ Flexibility and Efficiency Enhancements for Constrained Global Design Optimization With Kriging Approximations,” Ph.D. thesis, University of Michigan, Ann Arbor, MI.
Schonlau, M. , 1998, Computer Experiments and Global Optimization, University of Waterloo, Waterloo, ON, Canada.
Au, S. , and Beck, J. L. , 1999, “ A New Adaptive Importance Sampling Scheme for Reliability Calculations,” Struct. Saf., 21(2), pp. 135–158.
Basudhar, A. , and Missoum, S. , 2010, “ An Improved Adaptive Sampling Scheme for the Construction of Explicit Boundaries,” Struct. Multidiscip. Optim., 42(4), pp. 517–529.
Basudhar, A. , 2011, Computational Optimal Design and Uncertainty Quantification of Complex Systems Using Explicit Decision Boundaries, The University of Arizona, Tucson, AZ.
Tax, D. M. , and Duin, R. P. , 2004, “ Support Vector Data Description,” Mach. Learn., 54(1), pp. 45–66.
Le, T. , Tran, D. , Ma, W. , and Sharma, D. , 2012, “ A Unified Model for Support Vector Machine and Support Vector Data Description,” 2012 International Joint Conference on Neural Networks (IJCNN), IEEE, pp. 1–8.
Vapnik, V. , 1995, The Nature of Statistical Learning Theory, Springer, New York.
Scholkopf, B. , and Smola, J. A. , 2002, Learning With Kernels, MIT Press, Cambridge, MA.
Malak, J. R. J. , and Paredis, C. J. J. , 2010, “ Using Support Vector Machines to Formalize the Valid Input Domain of Predictive Models in Systems Design Problems,” ASME J. Mech. Des., 132(10), p. 101001.
Scholkopf, B. , Williamson, R. , Smola, A. , Shawe-Taylor, J. , and Platt, J. , 1999, “ Support Vector Method for Novelty Detection,” Advances in Neural Information Processing Systems, MIT Press, pp. 582–588.
Wolfe, P. , 1961, “ A Duality Theorem for Nonlinear Programming,” Q. Appl. Math., 19(3), pp. 239–244.
Cauwenberghs, G. , and Poggio, T. , 2001, “ Incremental and Decremental Support Vector Machine Learning,” Neural Information Processing Systems, 13, pp. 409–415.
MathWorks, 1998, “ Mathworks User's Guide,” Vol. 5, MathWorks Inc., Natick, MA, p. 333.
Tax, D. , 2005, “ Ddtools: The Data Description Toolbox for Matlab,” Delft University of Technology, Delft, Netherlands.
Tax, D. M. , 2015, “ Ddtools: The Data Description Toolbox for Matlab, Version 2.1.2,” Delft University of Technology, Delft, Netherlands.
Powers, D. M. , 2011, “ Evaluation: From Precision, Recall and F-Measure to ROC, Informedness, Markedness and Correlation,” J. Mach. Learn. Technol., 2(1), pp. 37–63.
## Figures
Fig. 1
Illustration of a CCSP. The function f(·) represents the nonlinear CALPHAD model that maps the thermodynamic condition space (a) to the phase constitution space (b). The query C=(C1,C2,…,C4) is defined by the user in the phase constitution space, e.g., C4≡(fβ≥c), where c is a constant. Due to the nonlinear mapping between the thermodynamic conditions space and the phase constitution space, the solution in the thermodynamic conditions space is nonconvex.
Fig. 4
Illustrative example depicting a possible step size and resulting endpoint from a given initial point along the boundary of the SVDD M. An aim in selecting a step size is to cross the boundary of the satisfactory region.
Fig. 2
Illustration of the SVDD method for two-dimensional training data. The training data depicted in (a) are implicitly mapped to (b), an N-D feature space where a hypersphere is a good representation of the population members. The hypersphere is defined by a centroid b and radius r. Equation (9) is a test to determine whether a new point z is inside the domain description. This test defines the boundary illustrated in (c).
Fig. 3
Comparison of SVM and SVDD on a simple classification problem, where the sampling is balanced (a) and imbalanced (b). The shading indicates the true classification, and the points are the training data.
Fig. 6
Algorithmic performance on test case 1 as measured by (a) precision, (b) recall, and (c) misclassification. Error bars indicate the mean values and 95% confidence interval of 30 trials.
Fig. 7
Algorithmic performance on test case 2 as measured by (a) precision, (b) recall, and (c) misclassification. Error bars indicate the mean values and 95% confidence interval of 30 trials.
Fig. 5
Phase diagram for Fe–Ti binary alloy system. The shaded regions correspond to the solution sets for test cases 1 and 2.
Fig. 8
Illustration of the progression of each algorithm at the function evaluations for test case 1. The top row corresponds to the progression of the GIPSP algorithm, and the bottom row corresponds to the EDSD algorithm. The satisfactory region is shaded, the samples are the points, and the classification boundaries are the outlines.
Fig. 9
Illustration of the progression of each algorithm at the (a) 100, (b) 250, and (c) 400, function evaluations for test case 2. The top row corresponds to the progression of the GIPSP algorithm, and the bottom row corresponds to the EDSD algorithm. The satisfactory region is shaded, the samples are the points, and the classification boundaries are the outlines.
Fig. 10
Illustration of a single trial of the EDSD algorithm at the 400 function evaluations for test case 2. The satisfactory region is shaded, the samples are the points, and the classification boundaries are the outlines. The results in this trial illustrate a possible overestimation of the EDSD algorithm in regions of the search space far from the true solution.
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• Themes
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# Fusion
15.11.2018
22:13 ExtremeTech.comChinese Fusion Reactor Gets 6 Times Hotter Than the Sun
The team operating the Experimental Advanced Superconducting Tokamak (EAST) managed to heat the reactor's internal plasma to 100 million degrees Celsius (212 million Fahrenheit).
The post Chinese Fusion Reactor Gets 6 Times Hotter Than the Sun appeared first on ExtremeTech.
15:24 Phys.orgChinese fusion tool pushes past 100 million degrees
The Experimental Advanced Superconducting Tokamak (EAST), nicknamed the "Chinese artificial sun," achieved an electron temperature of over 100 million degrees in its core plasma during a four-month experiment this year. That's about seven times greater than the interior of the sun, which is about 15 million degrees C.
07:30 Gizmag Fusion breakthrough as China's "artificial sun" reaches 100 million degrees
The day of clean, limitless energy from nuclear fusion has taken another step closer after China's Experimental Advanced Superconducting Tokamak (EAST) reached a core plasma temperature of over 100 million degrees Celsius (180 million degrees Fahrenheit). During a four-month experiment, the "Chinese artificial sun" achieved a temperature over six times greater than the interior of the Sun for around 10 seconds.
.. Continue Reading Fusion breakthrough as China's "artificial sun" reaches 100 million degrees Category: Energy Tags: China Fusion Nuclear
03:01 WhatReallyHappened.comReaching for the stars: China creates nuke-powered fake sun that burns hotter than the real deal
Chinese researchers pushing to find a major clean energy source have created an incredible artificial sun that can reach temperatures of 100 million degrees Celsius – a heat so intense it makes the real sun seem merely lukewarm.
The earth-based solar simulator has reached mind-bending temperatures of 100 million degrees Celsius, the research team announced Tuesday. Now, that’s hot. For comparison, the real sun’s core is about 15 million degrees Celsius.
The Institute of Plasma Physics, affiliated with the Chinese Academy of Sciences, said it has been testing an “artificial sun,” known as the Experimental Advanced Superconducting Tokamak (EAST). The sci-fi-sounding contraption has been designed to replicate the way in which the star at the center of our solar system generates its colossal energy.
14.11.2018
08:18 Arxiv.org StatisticsNeuroimaging Modality Fusion in Alzheimer's Classification Using Convolutional Neural Networks. (arXiv:1811.05105v1 [cs.LG])
Automated methods for Alzheimer's disease (AD) classification have the potential for great clinical benefits and may provide insight for combating the disease. Machine learning, and more specifically deep neural networks, have been shown to have great efficacy in this domain. These algorithms often use neurological imaging data such as MRI and PET, but a comprehensive and balanced comparison of these modalities has not been performed. In order to accurately determine the relative strength of each imaging variant, this work performs a comparison study in the context of Alzheimer's dementia classification using the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. Furthermore, this work analyzes the benefits of using both modalities in a fusion setting and discusses how these data types may be leveraged in future AD studies using deep learning.
07:56 Arxiv.org Quantitative BiologyNeuroimaging Modality Fusion in Alzheimer's Classification Using Convolutional Neural Networks. (arXiv:1811.05105v1 [cs.LG])
Automated methods for Alzheimer's disease (AD) classification have the potential for great clinical benefits and may provide insight for combating the disease. Machine learning, and more specifically deep neural networks, have been shown to have great efficacy in this domain. These algorithms often use neurological imaging data such as MRI and PET, but a comprehensive and balanced comparison of these modalities has not been performed. In order to accurately determine the relative strength of each imaging variant, this work performs a comparison study in the context of Alzheimer's dementia classification using the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. Furthermore, this work analyzes the benefits of using both modalities in a fusion setting and discusses how these data types may be leveraged in future AD studies using deep learning.
07:56 Arxiv.org CSFusionStitching: Deep Fusion and Code Generation for Tensorflow Computations on GPUs. (arXiv:1811.05213v1 [cs.DC])
In recent years, there is a surge on machine learning applications in industry. Many of them are based on popular AI frameworks like Tensorflow, Torch, Caffe, or MxNet, etc, and are enpowered by accelerator platforms such as GPUs. One important challenge of running Tensorflow computations on GPUs is the fine granularity problem, namely, FLOPS of individual ops are far from enough to fully exploit the computing power of underlying accelerators. The XLA framework provides a solid foundation to explore this problem further. In this paper, we propose FusionStitching, a novel, comprehensive Op fusion and code generation system to stitch computations into large GPU kernels. Experimental results on four public models and two of our large inhouse applications show another 55% (geometric mean) reduction of GPU kernel launches, compared to the XLA fusion baseline. This increases the E2E performance of
07:56 Arxiv.org CSNeuroimaging Modality Fusion in Alzheimer's Classification Using Convolutional Neural Networks. (arXiv:1811.05105v1 [cs.LG])
Automated methods for Alzheimer's disease (AD) classification have the potential for great clinical benefits and may provide insight for combating the disease. Machine learning, and more specifically deep neural networks, have been shown to have great efficacy in this domain. These algorithms often use neurological imaging data such as MRI and PET, but a comprehensive and balanced comparison of these modalities has not been performed. In order to accurately determine the relative strength of each imaging variant, this work performs a comparison study in the context of Alzheimer's dementia classification using the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset. Furthermore, this work analyzes the benefits of using both modalities in a fusion setting and discusses how these data types may be leveraged in future AD studies using deep learning.
13.11.2018
10:35 Arxiv.org PhysicsVacuum Solution for Solov'ev's Equilibrium Configuration in Tokamaks. (arXiv:1811.04443v1 [physics.plasm-ph])
In this work, we have revisited the Solov'ev analytical solution for a tokamak equilibrium. We point out that the vacuum solution in the Solov'ev formulation is inapplicable, since a distributed current density is assumed to fill the vacuum. The realistic vacuum should be current-free. To amend this vacuum solution problem, we use Green's function method to compute the plasma current contribution, together with a homogeneous solution to the Grad-Shafranov equation, to construct the full solution. Matching with the Solov'ev solution on the last closed flux surface is performed to determine the homogeneous solution. The total solution is then extended into the vacuum region to get a realistic vacuum solution. We find that the actual vacuum solution is different from the Solov'ev solution in the vacuum region, especially the X-point structure. The X-point obtained at the last closed flux surface
12.11.2018
06:21 Arxiv.org CSGender Effect on Face Recognition for a Large Longitudinal Database. (arXiv:1811.03680v1 [cs.CV])
Aging or gender variation can affect the face recognition performance dramatically. While most of the face recognition studies are focused on the variation of pose, illumination and expression, it is important to consider the influence of gender effect and how to design an effective matching framework. In this paper, we address these problems on a very large longitudinal database MORPH-II which contains 55,134 face images of 13,617 individuals. First, we consider four comprehensive experiments with different combination of gender distribution and subset size, including: 1) equal gender distribution; 2) a large highly unbalanced gender distribution; 3) consider different gender combinations, such as male only, female only, or mixed gender; and 4) the effect of subset size in terms of number of individuals. Second, we consider eight nearest neighbor distance metrics and also Support Vector
09.11.2018
07:40 Arxiv.org CSAttention Fusion Networks: Combining Behavior and E-mail Content to Improve Customer Support. (arXiv:1811.03169v1 [cs.CL])
Customer support is a central objective at Square as it helps us build and maintain great relationships with our sellers. In order to provide the best experience, we strive to deliver the most accurate and quasi-instantaneous responses to questions regarding our products.
In this work, we introduce the Attention Fusion Network model which combines signals extracted from seller interactions on the Square product ecosystem, along with submitted email questions, to predict the most relevant solution to a seller's inquiry. We show that the innovative combination of two very different data sources that are rarely used together, using state-of-the-art deep learning systems outperforms, candidate models that are trained only on a single source.
07.11.2018
18:52 ExtremeTech.comMIT Plans New Fusion Reactor That Could Actually Generate Power
MIT says it has the tools to make true fusion power happen, and it may be producing energy in a few years.
The post MIT Plans New Fusion Reactor That Could Actually Generate Power appeared first on ExtremeTech.
06.11.2018
08:49 Arxiv.org PhysicsFirst Commissioning Results of the Multicusp Ion Source at MIT (MIST-1) for H$_2^+$. (arXiv:1811.01868v1 [physics.acc-ph])
IsoDAR is an experiment under development to search for sterile neutrinos using the isotope Decay-At-Rest (DAR) production mechanism, where protons impinging on $^9$Be create neutrons which capture on $^7$Li which then beta-decays producing $\bar{\nu}_e$. As this will be an isotropic source of $\bar{\nu}_e$, the primary driver current must be large (10 mA cw) for IsoDAR to have sufficient statistics to be conclusive within 5 years of running. H$_2^+$ was chosen as primary ion to overcome some of the space-charge limitations during low energy beam transport and injection into a compact cyclotron. The H$_2^+$ will be stripped into protons before the target. At MIT, a multicusp ion source (MIST-1) was designed and built to produce a high intensity beam with a high H$_2^+$ fraction. MIST-1 is now operational at the Plasma Science and Fusion Center (PSFC) at MIT and under
05.11.2018
19:56 ScienceDaily.comA faster, cheaper path to fusion energy
Scientists are working to dramatically speed up the development of fusion energy in an effort to deliver power to the electric grid soon enough to help mitigate impacts of climate change. The arrival of a breakthrough technology -- high-temperature superconductors, which can be used to build magnets that produce stronger magnetic fields than previously possible -- could help them achieve this goal. Researchers plan to use this technology to build magnets at the scale required for fusion.
19:56 ScienceDaily.comInside job: A new technique to cool a fusion reactor
Fusion offers the potential of near limitless energy by heating a gas trapped in a magnetic field to incredibly high temperatures where atoms are so energetic that they fuse together when they collide. But if that hot gas, called a plasma, breaks free from the magnetic field, it must be safely put back in place to avoid damaging the fusion device -- this problem has been one of the great challenges of magnetically confined fusion.
19:56 ScienceDaily.comTaming plasmas: Improving fusion using microwaves
We all know microwaves are good for cooking popcorn, but scientists have recently shown they can also prevent dangerous waves in plasmas and help produce clean, nearly limitless energy with fusion. Fusion takes place when fast moving atomic particles slam into each other and stick together. The particles need to be so hot that atoms break down, leaving a gas of charged particles called a plasma.
19:56 ScienceDaily.comPeak performance: New stellarator experiments show promising results
Imagine building a machine so advanced and precise you need a supercomputer to help design it. That's exactly what scientists and engineers in Germany did when building the Wendelstein 7-X experiment. The device is a type of fusion device called a stellarator.
18:41 Phys.orgInside job: A new technique to cool a fusion reactor
Fusion offers the potential of near limitless energy by heating a gas trapped in a magnetic field to incredibly high temperatures where atoms are so energetic that they fuse together when they collide. But if that hot gas, called a plasma, breaks free from the magnetic field, it must be safely put back in place to avoid damaging the fusion device—this problem has been one of the great challenges of magnetically confined fusion.
18:41 Phys.orgTaming plasmas: Improving fusion using microwaves
We all know microwaves are good for cooking popcorn, but scientists have recently shown they can also prevent dangerous waves in plasmas and help produce clean, nearly limitless energy with fusion. Fusion takes place when fast moving atomic particles slam into each other and stick together. The particles need to be so hot that atoms break down, leaving a gas of charged particles called a plasma. The energy given off when plasma particles fuse can be harnessed to make electricity.
18:29 Phys.orgA faster, cheaper path to fusion energy
Scientists are working to dramatically speed up the development of fusion energy in an effort to deliver power to the electric grid soon enough to help mitigate impacts of climate change. The arrival of a breakthrough technology—high-temperature superconductors, which can be used to build magnets that produce stronger magnetic fields than previously possible—could help them achieve this goal. Researchers plan to use this technology to build magnets at the scale required for fusion, followed by construction of what would be the world's first fusion experiment to yield a net energy gain.
18:29 Phys.orgPeak performance: new stellarator experiments show promising results
Imagine building a machine so advanced and precise you need a supercomputer to help design it. That's exactly what scientists and engineers in Germany did when building the Wendelstein 7-X experiment. The device, funded by the German federal and state governments and the European Union, is a type of fusion device called a stellarator. The new experiment's goal is to contain a super-heated gas, called plasma, in a donut-shaped vessel using magnets that twist their way around the donut.
11:37 Arxiv.org StatisticsIndependent Vector Analysis for Data Fusion Prior to Molecular Property Prediction with Machine Learning. (arXiv:1811.00628v1 [stat.ML])
Due to its high computational speed and accuracy compared to ab-initio quantum chemistry and forcefield modeling, the prediction of molecular properties using machine learning has received great attention in the fields of materials design and drug discovery. A main ingredient required for machine learning is a training dataset consisting of molecular features\textemdash for example fingerprint bits, chemical descriptors, etc. that adequately characterize the corresponding molecules. However, choosing features for any application is highly non-trivial. No "universal" method for feature selection exists. In this work, we propose a data fusion framework that uses Independent Vector Analysis to exploit underlying complementary information contained in different molecular featurization methods, bringing us a step closer to automated feature generation. Our approach takes an arbitrary number of
11:26 Arxiv.org CSIndependent Vector Analysis for Data Fusion Prior to Molecular Property Prediction with Machine Learning. (arXiv:1811.00628v1 [stat.ML])
Due to its high computational speed and accuracy compared to ab-initio quantum chemistry and forcefield modeling, the prediction of molecular properties using machine learning has received great attention in the fields of materials design and drug discovery. A main ingredient required for machine learning is a training dataset consisting of molecular features\textemdash for example fingerprint bits, chemical descriptors, etc. that adequately characterize the corresponding molecules. However, choosing features for any application is highly non-trivial. No "universal" method for feature selection exists. In this work, we propose a data fusion framework that uses Independent Vector Analysis to exploit underlying complementary information contained in different molecular featurization methods, bringing us a step closer to automated feature generation. Our approach takes an arbitrary number of
02.11.2018
05:43 Arxiv.org PhysicsApplications of Deep Learning to Nuclear Fusion Research. (arXiv:1811.00333v1 [physics.plasm-ph])
Nuclear fusion is the process that powers the sun, and it is one of the best hopes to achieve a virtually unlimited energy source for the future of humanity. However, reproducing sustainable nuclear fusion reactions here on Earth is a tremendous scientific and technical challenge. Special devices -- called tokamaks -- have been built around the world, with JET (Joint European Torus, in the UK) being the largest tokamak currently in operation. Such devices confine matter and heat it up to extremely high temperatures, creating a plasma where fusion reactions begin to occur. JET has over one hundred diagnostic systems to monitor what happens inside the plasma, and each 30-second experiment (or pulse) generates about 50 GB of data. In this work, we show how convolutional neural networks (CNNs) can be used to reconstruct the 2D plasma profile inside the device based on data coming from those
05:43 Arxiv.org CSApplications of Deep Learning to Nuclear Fusion Research. (arXiv:1811.00333v1 [physics.plasm-ph])
Nuclear fusion is the process that powers the sun, and it is one of the best hopes to achieve a virtually unlimited energy source for the future of humanity. However, reproducing sustainable nuclear fusion reactions here on Earth is a tremendous scientific and technical challenge. Special devices -- called tokamaks -- have been built around the world, with JET (Joint European Torus, in the UK) being the largest tokamak currently in operation. Such devices confine matter and heat it up to extremely high temperatures, creating a plasma where fusion reactions begin to occur. JET has over one hundred diagnostic systems to monitor what happens inside the plasma, and each 30-second experiment (or pulse) generates about 50 GB of data. In this work, we show how convolutional neural networks (CNNs) can be used to reconstruct the 2D plasma profile inside the device based on data coming from those
05:43 Arxiv.org CSHybrid Self-Attention Network for Machine Translation. (arXiv:1811.00253v1 [cs.CL])
The encoder-decoder is the typical framework for Neural Machine Translation (NMT), and different structures have been developed for improving the translation performance. Transformer is one of the most promising structures, which can leverage the self-attention mechanism to capture the semantic dependency from global view. However, it cannot distinguish the relative position of different tokens very well, such as the tokens located at the left or right of the current token, and cannot focus on the local information around the current token either. To alleviate these problems, we propose a novel attention mechanism named Hybrid Self-Attention Network (HySAN) which accommodates some specific-designed masks for self-attention network to extract various semantic, such as the global/local information, the left/right part context. Finally, a squeeze gate is introduced to combine different kinds of
31.10.2018
04:14 Arxiv.org PhysicsThree Dimensional Pseudo-Spectral Compressible Magnetohydrodynamic GPU Code for Astrophysical Plasma Simulation. (arXiv:1810.12707v1 [physics.comp-ph])
This paper presents the benchmarking and scaling studies of a GPU accelerated three dimensional compressible magnetohydrodynamic code. The code is developed keeping an eye to explain the large and intermediate scale magnetic field generation is cosmos as well as in nuclear fusion reactors in the light of the theory given by Eugene Newman Parker. The spatial derivatives of the code are pseudo-spectral method based and the time solvers are explicit. GPU acceleration is achieved with minimal code changes through OpenACC parallelization and use of NVIDIA CUDA Fast Fourier Transform library (cuFFT). NVIDIAs unified memory is leveraged to enable over-subscription of the GPU device memory for seamless out-of-core processing of large grids. Our experimental results indicate that the GPU accelerated code is able to achieve upto two orders of magnitude speedup over a corresponding OpenMP parallel, FFTW
04:13 Arxiv.org CSCross-Modal Attentional Context Learning for RGB-D Object Detection. (arXiv:1810.12829v1 [cs.CV])
Recognizing objects from simultaneously sensed photometric (RGB) and depth channels is a fundamental yet practical problem in many machine vision applications such as robot grasping and autonomous driving. In this paper, we address this problem by developing a Cross-Modal Attentional Context (CMAC) learning framework, which enables the full exploitation of the context information from both RGB and depth data. Compared to existing RGB-D object detection frameworks, our approach has several appealing properties. First, it consists of an attention-based global context model for exploiting adaptive contextual information and incorporating this information into a region-based CNN (e.g., Fast RCNN) framework to achieve improved object detection performance. Second, our CMAC framework further contains a fine-grained object part attention module to harness multiple discriminative object parts inside
04:13 Arxiv.org CSSplitability Annotations: Optimizing Black-Box Function Composition in Existing Libraries. (arXiv:1810.12297v1 [cs.DC])
Data movement is a major bottleneck in parallel data-intensive applications. In response to this problem, researchers have proposed new runtimes and intermediate representations (IRs) that apply optimizations such as loop fusion under existing library APIs. Even though these runtimes generally do no require changes to user code, they require intrusive changes to the library itself: often, all the library functions need to be rewritten for a new IR or virtual machine. In this paper, we propose a new abstraction called splitability annotations (SAs) that enables key data movement optimizations on black-box library functions. SAs only require that users add an annotation for existing, unmodified functions and implement a small API to split data values in the library. Together, this interface describes how to partition values that are passed among functions to enable data pipelining and automatic
30.10.2018
07:13 Arxiv.org StatisticsShort-segment heart sound classification using an ensemble of deep convolutional neural networks. (arXiv:1810.11573v1 [cs.SD])
This paper proposes a framework based on deep convolutional neural networks (CNNs) for automatic heart sound classification using short-segments of individual heart beats. We design a 1D-CNN that directly learns features from raw heart-sound signals, and a 2D-CNN that takes inputs of two- dimensional time-frequency feature maps based on Mel-frequency cepstral coefficients (MFCC). We further develop a time-frequency CNN ensemble (TF-ECNN) combining the 1D-CNN and 2D-CNN based on score-level fusion of the class probabilities. On the large PhysioNet CinC challenge 2016 database, the proposed CNN models outperformed traditional classifiers based on support vector machine and hidden Markov models with various hand-crafted time- and frequency-domain features. Best classification scores with 89.22% accuracy and 89.94% sensitivity were achieved by the ECNN, and 91.55% specificity and 88.82% modified
07:02 Arxiv.org CSShort-segment heart sound classification using an ensemble of deep convolutional neural networks. (arXiv:1810.11573v1 [cs.SD])
This paper proposes a framework based on deep convolutional neural networks (CNNs) for automatic heart sound classification using short-segments of individual heart beats. We design a 1D-CNN that directly learns features from raw heart-sound signals, and a 2D-CNN that takes inputs of two- dimensional time-frequency feature maps based on Mel-frequency cepstral coefficients (MFCC). We further develop a time-frequency CNN ensemble (TF-ECNN) combining the 1D-CNN and 2D-CNN based on score-level fusion of the class probabilities. On the large PhysioNet CinC challenge 2016 database, the proposed CNN models outperformed traditional classifiers based on support vector machine and hidden Markov models with various hand-crafted time- and frequency-domain features. Best classification scores with 89.22% accuracy and 89.94% sensitivity were achieved by the ECNN, and 91.55% specificity and 88.82% modified
26.10.2018
03:39 Arxiv.org Quantitative BiologyInvestigating the Automatic Classification of Algae Using Fusion of Spectral and Morphological Characteristics of Algae via Deep Residual Learning. (arXiv:1810.10889v1 [cs.CV])
Under the impact of global climate changes and human activities, harmful algae blooms in surface waters have become a growing concern due to negative impacts on water related industries. Therefore, reliable and cost effective methods of quantifying the type and concentration of threshold levels of algae cells has become critical for ensuring successful water management. In this work, we present SAMSON, an innovative system to automatically classify multiple types of algae from different phyla groups by combining standard morphological features with their multi-wavelength signals. Two phyla with focused investigation in this study are the Cyanophyta phylum (blue-green algae), and the Chlorophyta phylum (green algae). We use a custom-designed microscopy imaging system which is configured to image water samples at two fluorescent wavelengths and seven absorption wavelengths using
03:39 Arxiv.org CSInvestigating the Automatic Classification of Algae Using Fusion of Spectral and Morphological Characteristics of Algae via Deep Residual Learning. (arXiv:1810.10889v1 [cs.CV])
Under the impact of global climate changes and human activities, harmful algae blooms in surface waters have become a growing concern due to negative impacts on water related industries. Therefore, reliable and cost effective methods of quantifying the type and concentration of threshold levels of algae cells has become critical for ensuring successful water management. In this work, we present SAMSON, an innovative system to automatically classify multiple types of algae from different phyla groups by combining standard morphological features with their multi-wavelength signals. Two phyla with focused investigation in this study are the Cyanophyta phylum (blue-green algae), and the Chlorophyta phylum (green algae). We use a custom-designed microscopy imaging system which is configured to image water samples at two fluorescent wavelengths and seven absorption wavelengths using
25.10.2018
06:21 Arxiv.org PhysicsSimulation of the electromagnetic wall response during Vertical Displacement Events (VDE) in ITER tokamak. (arXiv:1810.10277v1 [physics.plasm-ph])
The key basis for tokamak plasma disruption modeling is to understand how currents flow to the plasma facing surfaces during plasma disruption events. In ITER tokamak, the occurrence of a limited number of major disruptions will definitively damage the chamber with no possibility to restore the device. In the current exchange plasma-wall-plasma, according to the Helmholtz decomposition theorem, our surface current density in the conducting shell - the unknown of our problem - being a vector field twice continuously differentiable in 3D, has been splited into two components: an irrotational (curl-free) vector field and a solenoidal (divergence-free) vector field. Developing a weak formulation form and minimizing the correspondent energy functionals in a Finite Element approach, we have obtained the space and time distribution of the surface currents. We verified successfully our numerical
24.10.2018
20:53 ScienceDaily.comA first 'snapshot' of the complete spectrum of neutrinos emitted by the sun
About 99 percent of the sun's energy emitted as neutrinos is produced through nuclear reaction sequences initiated by proton-proton (pp) fusion in which hydrogen is converted into helium, say scientists.
20:09 Phys.orgA first 'snapshot' of the complete spectrum of neutrinos emitted by the sun
About 99 percent of the Sun's energy emitted as neutrinos is produced through nuclear reaction sequences initiated by proton-proton (pp) fusion in which hydrogen is converted into helium, say scientists including physicist Andrea Pocar at the University of Massachusetts Amherst. Today they report new results from Borexino, one of the most sensitive neutrino detectors on the planet, located deep beneath Italy's Apennine Mountains.
22.10.2018
07:16 Arxiv.org PhysicsStrategy and guidelines for the calibration of the ITER radial neutron camera. (arXiv:1810.08582v1 [physics.ins-det])
A calibration procedure is proposed for the ITER Radial Neutron Camera. No in-vessel calibration using external neutron sources is required: instead, it is proposed to rely on embedded sources, reference ITER pulses and cross-calibration with ITER fission chambers and activation system coupled to Monte Carlo simulations of radiation transport for the validation of the RNC calibration and for its tracking during ITER lifetime.
19.10.2018
15:59 Phys.orgNew simulations confirm efficiency of waste-removal process in plasma device
Just as fire produces ash, the combining of light elements in fusion reactions can produce material that eventually interferes with those same reactions. Now, scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have found evidence suggesting that a process could remove the unwanted material and make the fusion processes more efficient within a type of fusion facility known as a field-reversed configuration (FRC) device.
18.10.2018
14:52 CNNHypersonic, nuclear airplanes of the future
From blended wing airliners powered by nuclear fusion to a new generation of spacecraft designed to carry tourists to the moon, it's hard not to be mesmerized by Oscar Viñals' boldly ambitious aircraft designs.
16.10.2018
09:23 Arxiv.org PhysicsLiquid scintillators neutron response function: a tutorial. (arXiv:1810.06263v1 [physics.ins-det])
This tutorial is devoted to the understanding of the different components that are present in the neutron light output pulse height distribution of liquid scintillators in fusion relevant energy ranges. The basic mechanisms for the generation of the scintillation light are briefly discussed. The different elastic collision processed between the incident neutrons and the hydrogen and carbon atoms are described in terms of probability density functions and the overall response function as their convolution. The results from this analytical approach is then compared with those obtained from simplified and full Monte Carlo simulations. Edge effect, finite energy resolution, light output and transport and competing physical processes between neutron and carbon and hydrogen atoms and their impact on the response functions are discussed. Although the analytical treatment here presented allows only
15.10.2018
05:05 Arxiv.org PhysicsDynamics of cold pulses induced by super-sonic molecular beam injection in the EAST tokamak. (arXiv:1810.05352v1 [physics.plasm-ph])
Evolution of electron temperature, electron density and its fluctuation with high spatial and temporal resolutions are presented for the cold pulse propagation induced by super-sonic molecular beam injection (SMBI) in ohmic plasmas in the EAST tokamak. The non-local heat transport occurs for discharges with plasma current $I_p$=450 kA ($q_{95}\sim5.55$), and electron density $n_{e0}$ below a critical value of $(1.35\pm0.25)\times10^{19}~\mathrm{m^{-3}}$. In contrary to the response of core electron temperature and electron density (roughly 10 ms after SMBI), the electron density fluctuation in the plasma core increases promptly after SMBI and reaches its maximum around 15 ms after SMBI. The electron density fluctuation in the plasma core begins to decrease before the core electron temperature reaches its maximum (roughly 30 ms). It was also observed that the turbulence perpendicular velocity
05:05 Arxiv.org PhysicsNonlinear dynamics of Shear Alfv\'en fluctuations in Divertor Tokamak Test facility plasmas. (arXiv:1810.05327v1 [physics.plasm-ph])
Following the analysis on linear spectra of shear Alfv\'en fluctuations excited by energetic particles (EPs) in the Divertor Tokamak Test (DTT) facility plasmas [T. Wang et al., Phys. Plasmas 25, 062509 (2018)], in this work, nonlinear dynamics of the corresponding mode saturation and the fluctuation induced EP transport is studied by hybrid magnetohydrodynamic-gyrokinetic simulations. For the reversed shear Alfv\'en eigenmode driven by magnetically trapped EP precession resonance in the central core region of DTT plasmas, the saturation is mainly due to radial decoupling of resonant trapped EPs. Consistent with the wave-EP resonance structure, EP transport occurs in a similar scale to the mode width. On the other hand, passing EP transport is analyzed in detail for toroidal Alfv\'en eigenmode in the outer core region, with mode drive from both passing and trapped EPs. It is shown that
12.10.2018
21:06 Aljazeera.NetScientists to build a new prototype nuclear fusion reactor
If successful, the project could be the answer to the world’s clean energy needs.
05:50 Arxiv.org PhysicsAn improved understanding of the roles of atomic processes and power balance in divertor target ion current loss during detachment. (arXiv:1810.04969v1 [physics.plasm-ph])
The physics leading to the decrease of the divertor ion current ($I_t$), or 'roll-over' during detachment for divertor power exhaust in tokamaks is experimentally explored on the TCV tokamak through characterization of the location, magnitude and role of the various divertor ion sinks and sources including a complete measure of particle and power balance. These first measurements of the profiles of divertor ionisation and hydrogenic radiation along the divertor leg are enabled through novel spectroscopic techniques which are introduced.
Over a range in TCV plasma conditions (plasma current, impurity-seeding, density) the $I_t$ roll-over is caused by a drop in the divertor ion source; recombination remains either small or negligible until later in the detachment process. In agreement with simple analytical predictions, this ion source reduction is driven by a reduction in the power
05:50 Arxiv.org PhysicsProperties of a new quasi-axisymmetric configuration. (arXiv:1810.04914v1 [physics.plasm-ph])
A novel, compact, quasi-axisymmetric configuration is presented which exhibits low fast-particle losses and is stable to ideal MHD instabilities. The design has fast-particle loss rates below 8\% for flux surfaces within the half-radius, and is shown to have an MHD-stability limit of a normalised pressure of $\langle\beta\rangle=3\%$ where $\langle\beta\rangle$ is volume averaged. The flux surfaces at various plasma betas and currents as calculated using the SPEC equilibrium code are presented. Neoclassical transport coefficients are shown to be similar to an equivalent tokamak, with a distinct banana regime at half-radius. An initial coil design study is presented to assess the feasibility of this configuration as a fusion-relevant experiment.
11.10.2018
08:32 Arxiv.org PhysicsThe effects of non-uniform drive on plasma filaments. (arXiv:1810.04584v1 [physics.plasm-ph])
Wendelstein 7-X core fueling is primarily achieved through pellet injection. The trajectory of plasmoids from an ablating pellet is an ongoing research question, which is complicated by the complex magnetic geometry of W7-X; curvature drive varies significantly toroidally, including a change in the drift drive direction. Here we use the Hermes model in BOUT++ to simulate cold plasma filaments in slab geometries where the magnetic drift drive is non-uniform along the field line. It is shown that if the field-line-averaged curvature drive is non-zero, a filament will propagate coherently in the direction of average drive. It is also shown that a non-uniform drive will provide a non- uniform propagation; an effect which is reduced at higher temperatures due to an increased sound speed along the field line. Finally, simulations with curvature similar to that found in Wendelstein 7-X are performed
10.10.2018
09:47 Phys.orgNovel design could help shed excess heat in next-generation fusion power plants
A class exercise at MIT, aided by industry researchers, has led to an innovative solution to one of the longstanding challenges facing the development of practical fusion power plants: how to get rid of excess heat that would cause structural damage to the plant.
09:04 Technology.orgA new path to solving a longstanding fusion challenge
A class exercise at MIT, aided by industry researchers, has led to an innovative solution to one of
09.10.2018
06:48 Arxiv.org StatisticsSparse Regression with Multi-type Regularized Feature Modeling. (arXiv:1810.03136v1 [stat.CO])
Within the statistical and machine learning literature, regularization techniques are often used to construct sparse (predictive) models. Most regularization strategies only work for data where all predictors are of the same type, such as Lasso regression for continuous predictors. However, many predictive problems involve different predictor types. We propose a multi-type Lasso penalty that acts on the objective function as a sum of subpenalties, one for each predictor type. As such, we perform predictor selection and level fusion within a predictor in a data-driven way, simultaneous with the parameter estimation process. We develop a new estimation strategy for convex predictive models with this multi-type penalty. Using the theory of proximal operators, our estimation procedure is computationally efficient, partitioning the overall optimization problem into easier to solve subproblems,
06:47 Arxiv.org PhysicsStudies of Reynolds Stress and the Turbulent Generation of Edge Poloidal Flows on the HL-@A Tokamak. (arXiv:1810.03588v1 [physics.plasm-ph])
Several new results in the physics of edge poloidal flows, turbulent stresses and momentum transport are reported. These are based on experiments on the HL-2A tokamak. Significant deviation from neoclassical prediction for mean poloidal flow in Ohmic and L mode discharges is deduced from direct measurements of the turbulent Reynolds stress. The deviation increases with heating power. The turbulent poloidal viscosity is synthesized from fluctuation data, and is found to be comparable to the turbulent particle diffusivity. The intrinsic poloidal torque is deduced from synthesis, for the first time. PDFs of particle flux and Reynolds stress are obtained. Both exhibit fat tails and large kurtosis, suggesting that the momentum transport process represented by the Reynolds stress is not well described by quasilinear calculations.
08.10.2018
09:27 Arxiv.org PhysicsSpatiotemporal evolution of runaway electrons from synchrotron images in Alcator C-Mod. (arXiv:1810.02742v1 [physics.plasm-ph])
In the Alcator C-Mod tokamak, relativistic runaway electron (RE) generation can occur during the flattop current phase of low density, diverted plasma discharges. Due to the high toroidal magnetic field (B = 5.4 T), RE synchrotron radiation is measured by a wide-view camera in the visible wavelength range (~400-900 nm). In this paper, a statistical analysis of over one thousand camera images is performed to investigate the plasma conditions under which synchrotron emission is observed in C-Mod. In addition, the spatiotemporal evolution of REs during one particular discharge is explored in detail via a thorough analysis of the distortion-corrected synchrotron images. To accurately predict RE energies, the kinetic solver CODE [Landreman et al 2014 Comput. Phys. Commun. 185 847-855] is used to evolve the electron momentum-space distribution at six locations throughout the plasma: the magnetic
03.10.2018
08:54 Arxiv.org PhysicsThe role of incidence angle in the laser ablation of planar ICF targets. (arXiv:1810.01004v1 [physics.plasm-ph])
The effect of the laser ray incidence angle on the mass ablation rate and ablation pressure of planar inertial confinement fusion (ICF) targets is explored using an idealized model. Polar direct drive (PDD) on the National Ignition Facility (NIF) requires the repointing of its 192 beams clustered within 50 degrees of the poles to minimize the imparted polar varying payload kinetic energy of the target. Due to this repointing, non-normal incidence angles of the beam centerlines are encountered in any PDD design. The formulation of a PDD scheme that minimizes non-uniformity is a significant challenge that requires an understanding of the induced differences in ablation including those of incidence angle. In this work, a modified version of the textbook model of laser ablation [Manheimer et al. Phys. Fluids 25, 1644 (1982)] is used to demonstrate that the mass ablation rate and ablation pressure
08:54 Arxiv.org CSFusion of Monocular Vision and Radio-based Ranging for Global Scale Estimation and Drift Mitigation. (arXiv:1810.01346v1 [cs.RO])
Monocular vision-based Simultaneous Localization and Mapping (SLAM) is used for various purposes due to its advantages in cost, simple setup, as well as availability in the environments where navigation with satellites is not effective. However, camera motion and map points can be estimated only up to a global scale factor with monocular vision. Moreover, estimation error accumulates over time without bound, if the camera cannot detect the previously observed map points for closing a loop. We propose an innovative approach to estimate a global scale factor and reduce drifts in monocular vision-based localization with an additional single ranging link. Our method can be easily integrated with the back-end of monocular visual SLAM methods. We demonstrate our algorithm with real datasets collected on a rover, and show the evaluation results.
08:54 Arxiv.org CSMarrying Tracking with ELM: A Metric Constraint Guided Multiple Feature Fusion Method. (arXiv:1810.01271v1 [cs.CV])
Object Tracking is one important problem in computer vision and surveillance system. The existing models mainly exploit the single-view feature (i.e. color, texture, shape) to solve the problem, failing to describe the objects comprehensively. In this paper, we solve the problem from multi-view perspective by leveraging multi-view complementary and latent information, so as to be robust to the partial occlusion and background clutter especially when the objects are similar to the target, meanwhile addressing tracking drift. However, one big problem is that multi-view fusion strategy can inevitably result tracking into non-efficiency. To this end, we propose to marry ELM (Extreme learning machine) to multi-view fusion to train the global hidden output weight, to effectively exploit the local information from each view. Following this principle, we propose a novel method to obtain the optimal
02.10.2018
16:03 Phys.orgAttempting to tame plasmas in fusion
Nuclear fusion, the release of energy when light atomic nuclei merge, is touted as a carbon-free solution to global energy requirements. One potential route to nuclear fusion is inertial confinement. Now a KAUST-led team has modeled the complex flow of plasma that could occur in such a fusion reactor.
28.09.2018
08:30 Arxiv.org PhysicsConceptual design study for heat exhaust management in the ARC fusion pilot plant. (arXiv:1809.10555v1 [physics.ins-det])
The ARC pilot plant conceptual design study has been extended beyond its initial scope [B. N. Sorbom et al., FED 100 (2015) 378] to explore options for managing ~525 MW of fusion power generated in a compact, high field (B_0 = 9.2 T) tokamak that is approximately the size of JET (R_0 = 3.3 m). Taking advantage of ARC's novel design - demountable high temperature superconductor toroidal field (TF) magnets, poloidal magnetic field coils located inside the TF, and vacuum vessel (VV) immersed in molten salt FLiBe blanket - this follow-on study has identified innovative and potentially robust power exhaust management solutions.
08:30 Arxiv.org PhysicsQuenching factor measurement for a NaI(Tl) scintillation crystal. (arXiv:1809.10310v1 [physics.ins-det])
Scintillation crystals are commonly used for direct detection of a weakly interacting massive particle (WIMP), which is a good candidate of a particle dark matter. It is well known that scintillation light yields are different between electron recoil and nuclear recoil. To calibrate energies of WIMP-induced nuclear recoil signals, one needs to measure a quenching factor (QF), light yield ratio of nuclear recoil to electron recoil. Measurements of the QFs for Na and I recoils in a small (2 cm x 2 cm x 1.5 cm) NaI(Tl) crystal have been performed with 2.43 MeV mono-energetic neutrons generated from deuteron-deuteron fusion. Depending on the scattering angle of the neutrons, energies of recoiled ions vary from 9 to 150 keV for Na and 19 to 75 keV for I. QFs of Na are measured at 9 points with the values from 10 % to 23 % and those of I are measured at 4 points with the values from 4 % to 6
08:30 Arxiv.org PhysicsDirect construction of optimized stellarator shapes. II. Numerical quasisymmetric solutions. (arXiv:1809.10246v1 [physics.plasm-ph])
Quasisymmetric stellarators are appealing intellectually and as fusion reactor candidates since the guiding center particle trajectories and neoclassical transport are isomorphic to those in a tokamak, despite the lack of true axisymmetry. Previously, quasisymmetric magnetic fields have been identified by applying black-box optimization algorithms to minimize symmetry-breaking Fourier modes of the field strength $B$. Here instead we directly construct magnetic fields in cylindrical coordinates that are quasisymmetric to leading order in distance from the magnetic axis, without using optimization. The method involves solution of a 1-dimensional nonlinear ordinary differential equation, originally derived by Garren and Boozer [Phys. Fluids B 3, 2805 (1991)]. We demonstrate the usefulness and accuracy of this optimization-free approach by providing the results of this construction as input to
08:30 Arxiv.org PhysicsDirect construction of optimized stellarator shapes. I. Theory in cylindrical coordinates. (arXiv:1809.10233v1 [physics.plasm-ph])
The confinement of guiding center trajectories in a stellarator is determined by the variation of the magnetic field strength $B$ in Boozer coordinates $(r, \theta, \varphi)$, but $B(r,\theta,\varphi)$ depends on the flux surface shape in a complicated way. Here we derive equations relating $B(r,\theta,\varphi)$ in Boozer coordinates and the rotational transform to the shape of flux surfaces in cylindrical coordinates, using an expansion in distance from the magnetic axis. A related expansion was done by Garren and Boozer [Phys. Fluids B 3, 2805 (1991)] based on the Frenet-Serret frame, which can be discontinuous anywhere the magnetic axis is straight, a situation that occurs in the interesting case of omnigenity with poloidally closed $B$ contours. Our calculation in contrast does not use the Frenet-Serret frame. The transformation between the Garren-Boozer approach and cylindrical
26.09.2018
07:05 Arxiv.org PhysicsLow-shear three-dimensional equilibria and vacuum magnetic fields with flux surfaces. (arXiv:1809.09225v1 [physics.plasm-ph])
Stellarators are generically small current and relatively low plasma beta ($\beta= p/B^2\ll1$) devices. Often the construction of vacuum magnetic fields with relatively good magnetic surfaces is the starting point for an equilibrium calculation. Although in cases with some continuous spatial symmetry flux functions can always be found for vacuum magnetic fields, an analogous function does not, in general, exist in three dimensions. This work examines several relatively simple equilibrium and vacuum magnetic field problems with the intent of demonstrating the possibilities and limitations in the construction of such states. Starting with a very simple vacuum magnetic field with closed field lines in a topological torus, we obtain a self-consistent formal perturbation series using the amplitude of the non-symmetric vacuum fields as a small parameter. We show that systems possessing
25.09.2018
09:39 Arxiv.org MathSpectrum and Energy Efficient Multiple Access for Detection in Wireless Sensor Networks. (arXiv:1809.08468v1 [cs.IT])
We consider a binary hypothesis testing problem using Wireless Sensor Networks (WSNs). The decision is made by a fusion center and is based on received data from the sensors. We focus on a spectrum and energy efficient transmission scheme used to reduce the spectrum usage and energy consumption during the detection task. We propose a Spectrum and Energy Efficient Multiple Access (SEEMA) transmission protocol that performs a censoring-type transmission based on the density of observations using multiple access channels (MAC). Specifically, in SEEMA, only sensors with highly informative observations transmit their data in each data collection. The sensors transmit a common shaping waveform and the fusion center receives a superposition of the analog transmitted signals. SEEMA has important advantages for detection tasks in WSNs. First, it is highly energy and bandwidth efficient due to
09:39 Arxiv.org CSSpectrum and Energy Efficient Multiple Access for Detection in Wireless Sensor Networks. (arXiv:1809.08468v1 [cs.IT])
We consider a binary hypothesis testing problem using Wireless Sensor Networks (WSNs). The decision is made by a fusion center and is based on received data from the sensors. We focus on a spectrum and energy efficient transmission scheme used to reduce the spectrum usage and energy consumption during the detection task. We propose a Spectrum and Energy Efficient Multiple Access (SEEMA) transmission protocol that performs a censoring-type transmission based on the density of observations using multiple access channels (MAC). Specifically, in SEEMA, only sensors with highly informative observations transmit their data in each data collection. The sensors transmit a common shaping waveform and the fusion center receives a superposition of the analog transmitted signals. SEEMA has important advantages for detection tasks in WSNs. First, it is highly energy and bandwidth efficient due to
21.09.2018
09:42 Phys.orgNeutrons produce first direct 3-D maps of water during cell membrane fusion
New 3-D maps of water distribution during cellular membrane fusion are accelerating scientific understanding of cell development, which could lead to new treatments for diseases associated with cell fusion. Using neutron diffraction at the Department of Energy's Oak Ridge National Laboratory, researchers have made the first direct observations of water in lipid bilayers used to model cell membrane fusion.
20.09.2018
09:16 Arxiv.org PhysicsDependence of Alfv\'en eigenmode linear stability on device magnetic field strength and consequences for next-generation tokamaks. (arXiv:1809.07278v1 [physics.plasm-ph])
Recently-proposed tokamak concepts use magnetic fields up to 12 T, far higher than in conventional devices, to reduce size and cost. Theoretical and computational study of trends in plasma behavior with increasing field strength is critical to such proposed devices. This paper considers trends in Alfv\'en eigenmode (AE) stability. Energetic particles, including alphas from D-T fusion, can destabilize AEs, possibly causing loss of alpha heat and damage to the device. AEs are sensitive to device magnetic field via the field dependence of resonances, alpha particle beta, and alpha orbit width. We describe the origin and effect of these dependences analytically and by using recently-developed numerical techniques (Rodrigues et al. 2015 Nucl. Fusion 55 083003). The work suggests high-field machines where fusion-born alphas are sub-Alfv\'enic or nearly sub-Alfv\'enic may partially cut off AE
18.09.2018
07:48 Arxiv.org CSHierarchical Graphical Models for Context-Aware Hybrid Brain-Machine Interfaces. (arXiv:1809.05635v1 [cs.HC])
We present a novel hierarchical graphical model based context-aware hybrid brain-machine interface (hBMI) using probabilistic fusion of electroencephalographic (EEG) and electromyographic (EMG) activities. Based on experimental data collected during stationary executions and subsequent imageries of five different hand gestures with both limbs, we demonstrate feasibility of the proposed hBMI system through within session and online across sessions classification analyses. Furthermore, we investigate the context-aware extent of the model by a simulated probabilistic approach and highlight potential implications of our work in the field of neurophysiologically-driven robotic hand prosthetics.
02:45 ScienceDaily.comNew world record magnetic field
Researchers have recorded the highest magnetic field ever achieved indoors -- a discovery that may open doors for materials science and fusion energy research.
12.09.2018
10:20 Arxiv.org MathEnergy-efficient Decision Fusion for Distributed Detection in Wireless Sensor Networks. (arXiv:1809.03653v1 [cs.IT])
This paper proposes an energy-efficient counting rule for distributed detection by ordering sensor transmissions in wireless sensor networks. In the counting rule-based detection in an $N-$sensor network, the local sensors transmit binary decisions to the fusion center, where the number of all $N$ local-sensor detections are counted and compared to a threshold. In the ordering scheme, sensors transmit their unquantized statistics to the fusion center in a sequential manner; highly informative sensors enjoy higher priority for transmission. When sufficient evidence is collected at the fusion center for decision making, the transmissions from the sensors are stopped. The ordering scheme achieves the same error probability as the optimum unconstrained energy approach (which requires observations from all the $N$ sensors) with far fewer sensor transmissions. The scheme proposed in this paper
10:20 Arxiv.org CS3D Inception-based CNN with sMRI and MD-DTI data fusion for Alzheimer's Disease diagnostics. (arXiv:1809.03972v1 [cs.CV])
In the last decade, computer-aided early diagnostics of Alzheimer's Disease (AD) and its prodromal form, Mild Cognitive Impairment (MCI), has been the subject of extensive research. Some recent studies have shown promising results in the AD and MCI determination using structural and functional Magnetic Resonance Imaging (sMRI, fMRI), Positron Emission Tomography (PET) and Diffusion Tensor Imaging (DTI) modalities. Furthermore, fusion of imaging modalities in a supervised machine learning framework has shown promising direction of research.
In this paper we first review major trends in automatic classification methods such as feature extraction based methods as well as deep learning approaches in medical image analysis applied to the field of Alzheimer's Disease diagnostics. Then we propose our own design of a 3D Inception-based Convolutional Neural Network (CNN) for Alzheimer's Disease
10:20 Arxiv.org CSEnergy-efficient Decision Fusion for Distributed Detection in Wireless Sensor Networks. (arXiv:1809.03653v1 [cs.IT])
This paper proposes an energy-efficient counting rule for distributed detection by ordering sensor transmissions in wireless sensor networks. In the counting rule-based detection in an $N-$sensor network, the local sensors transmit binary decisions to the fusion center, where the number of all $N$ local-sensor detections are counted and compared to a threshold. In the ordering scheme, sensors transmit their unquantized statistics to the fusion center in a sequential manner; highly informative sensors enjoy higher priority for transmission. When sufficient evidence is collected at the fusion center for decision making, the transmissions from the sensors are stopped. The ordering scheme achieves the same error probability as the optimum unconstrained energy approach (which requires observations from all the $N$ sensors) with far fewer sensor transmissions. The scheme proposed in this paper
11.09.2018
22:49 ScienceDaily.comSeparating the sound from the noise in hot plasma fusion
For fusion power plants to be effective, scientists must find a way to trigger the low-to-high confinement transition, associated with zonal flows of plasma. Theoretically, these consist of both a stationary flow and one that oscillates at the geodesic acoustic mode. For the first time, researchers have detected GAM at two different points simultaneously within the reactor. This experimental setup will aid investigating the physics of zonal flows, and their role in the L-H transition.
18:08 Phys.orgSeparating the sound from the noise in hot plasma fusion
In the search for abundant clean energy, scientists around the globe look to fusion power, where isotopes of hydrogen combine to form a larger particle, helium, and release large amounts of energy in the process. For fusion power plants to be effective, however, scientists must find a way to trigger the low-to-high confinement transition, or "L-H transition" for short. After a L-H transition, the plasma temperature and density increase, producing more power.
05:55 Arxiv.org PhysicsFirst Investigation on the Radiation Field of the Gas-Filled Three-Axis Cylindrical Hohlraum. (arXiv:1809.03284v1 [physics.plasm-ph])
A novel ignition hohlraum named three-axis cylindrical hohlraum (TACH) is designed for indirect-drive inertial confinement fusion. TACH is a kind of 6 laser entrance holes (LEHs) hohlraum, which is orthogonally jointed of three cylindrical hohlraums. The first experiment on the radiation field of TACH was performed on Shenguang III laser facility. 24 laser beams were elected and injected into 6 LEHs quasi-symmetrically. Total laser energy was about 59 kJ, and the peak radiation temperature reached about 192 eV. Radiation temperature and pinhole images in gas-filled hohlraum are largely identical but with minor differences with those in vacuum hohlraum. All laser energy can be totally delivered into hohlraum in 3 ns duration even without filled gas in the hohlraum of 1.4 mm diameter. Plasma filling cannot be obviously suppressed even with 0.5 atm pressure gas in the small hohlraum.
05:55 Arxiv.org PhysicsThe conceptual design of 100-kA pulsed magnetic field generator for magnetized high-energy-density plasma experiments. (arXiv:1809.03278v1 [physics.plasm-ph])
This paper presents the conceptual design of a high-voltage pulser intended to generate 30-T magnetic fields for magneto-inertial fusion experiments at the OMEGA facility. The pulser uses a custom capacitor bank and two externally triggered spark gaps to drive a multi-turn coil. This new high-voltage pulser is capable of storing 10 times more energy than the previous system, using a higher charge voltage (from 20 to 30 kV) and a larger capacitance (from 1 {\mu}F to 5 {\mu}F). Circuit simulations show that this pulser can deliver 100 kA into a 60-nH, 14-m{\Omega} coil with a rise time of 1 {\mu}s. For a coil with 2 turns with an average coil diameter of 7.8 mm, this current translates into a 32-T peak magnetic field at coil center. This is a factor of three increase in the peak magnetic field compared to the present generator magnetic field capabilities.
10.09.2018
18:09 Phys.orgDiscovered: Optimal magnetic fields for suppressing instabilities in tokamaks
Fusion, the power that drives the sun and stars, produces massive amounts of energy. Scientists here on Earth seek to replicate this process, which merges light elements in the form of hot, charged plasma composed of free electrons and atomic nuclei, to create a virtually inexhaustible supply of power to generate electricity in what may be called a "star in a jar."
08:32 Arxiv.org CSPredicting Lung Nodule Malignancies by Combining Deep Convolutional Neural Network and Handcrafted Features. (arXiv:1809.02333v1 [cs.CV])
To predict lung nodule malignancy with a high sensitivity and specificity, we propose a fusion algorithm that combines handcrafted features (HF) into the features learned at the output layer of a 3D deep convolutional neural network (CNN). First, we extracted twenty-nine handcrafted features, including nine intensity features, eight geometric features, and twelve texture features based on grey-level co-occurrence matrix (GLCM) averaged from thirteen directions. We then trained 3D CNNs modified from three state-of-the-art 2D CNN architectures (AlexNet, VGG-16 Net and Multi-crop Net) to extract the CNN features learned at the output layer. For each 3D CNN, the CNN features combined with the 29 handcrafted features were used as the input for the support vector machine (SVM) coupled with the sequential forward feature selection (SFS) method to select the optimal feature subset and construct the
08.09.2018
01:28 WhatReallyHappened.comPluto SHOULD be a planet: Astronomers claim controversial demotion was based on 'since-disproven reasoning'
Scientists have proposed a new way to define planets based on 'the physics of the world itself.'
By the proposed geophysical definition: 'A planet is a sub-stellar mass body that has never undergone nuclear fusion and that has sufficient self-gravitation to assume a spheroidal shape adequately described by a triaxial ellipsoid regardless of its orbital parameters.'
Or, simply put, 'round objects in space that are smaller than stars.'
05.09.2018
07:39 Arxiv.org MathTowards an Intelligent Edge: Wireless Communication Meets Machine Learning. (arXiv:1809.00343v1 [cs.IT])
The recent revival of artificial intelligence (AI) is revolutionizing almost every branch of science and technology. Given the ubiquitous smart mobile gadgets and Internet of Things (IoT) devices, it is expected that a majority of intelligent applications will be deployed at the edge of wireless networks. This trend has generated strong interests in realizing an "intelligent edge" to support AI-enabled applications at various edge devices. Accordingly, a new research area, called edge learning, emerges, which crosses and revolutionizes two disciplines: wireless communication and machine learning. A major theme in edge learning is to overcome the limited computing power, as well as limited data, at each edge device. This is accomplished by leveraging the mobile edge computing (MEC) platform and exploiting the massive data distributed over a large number of edge devices. In such systems,
07:38 Arxiv.org CSTowards an Intelligent Edge: Wireless Communication Meets Machine Learning. (arXiv:1809.00343v1 [cs.IT])
The recent revival of artificial intelligence (AI) is revolutionizing almost every branch of science and technology. Given the ubiquitous smart mobile gadgets and Internet of Things (IoT) devices, it is expected that a majority of intelligent applications will be deployed at the edge of wireless networks. This trend has generated strong interests in realizing an "intelligent edge" to support AI-enabled applications at various edge devices. Accordingly, a new research area, called edge learning, emerges, which crosses and revolutionizes two disciplines: wireless communication and machine learning. A major theme in edge learning is to overcome the limited computing power, as well as limited data, at each edge device. This is accomplished by leveraging the mobile edge computing (MEC) platform and exploiting the massive data distributed over a large number of edge devices. In such systems,
07:38 Arxiv.org CSSimple Fusion: Return of the Language Model. (arXiv:1809.00125v1 [cs.CL])
Neural Machine Translation (NMT) typically leverages monolingual data in training through backtranslation. We investigate an alternative simple method to use monolingual data for NMT training: We combine the scores of a pre-trained and fixed language model (LM) with the scores of a translation model (TM) while the TM is trained from scratch. To achieve that, we train the translation model to predict the residual probability of the training data added to the prediction of the LM. This enables the TM to focus its capacity on modeling the source sentence since it can rely on the LM for fluency. We show that our method outperforms previous approaches to integrate LMs into NMT while the architecture is simpler as it does not require gating networks to balance TM and LM. We observe gains of between +0.24 and +2.36 BLEU on all four test sets (English-Turkish, Turkish-English, Estonian-English,
03.09.2018
05:57 Arxiv.org CSMMDF2018 Workshop Report. (arXiv:1808.10721v1 [cs.OH])
Driven by the recent advances in smart, miniaturized, and mass produced sensors, networked systems, and high-speed data communication and computing, the ability to collect and process larger volumes of higher veracity real-time data from a variety of modalities is expanding. However, despite research thrusts explored since the late 1990's, to date no standard, generalizable solutions have emerged for effectively integrating and processing multimodal data, and consequently practitioners across a wide variety of disciplines must still follow a trial-and-error process to identify the optimum procedure for each individual application and data sources. A deeper understanding of the utility and capabilities (as well as the shortcomings and challenges) of existing multimodal data fusion methods as a function of data and challenge characteristics has the potential to deliver better data analysis
31.08.2018
07:05 Arxiv.org PhysicsA Facility for Production and Laser Cooling of Cesium Isotopes and Isomers. (arXiv:1808.10280v1 [physics.ins-det])
We report on the design, installation, and test of an experimental facility for the production of ultra-cold atomic isotopes and isomers of cesium. The setup covers a broad span of mass numbers and nuclear isomers, allowing one to directly compare chains of isotopes and isotope/isomer pairs. Cesium nuclei are produced by fission or fusion-evaporation reactions using primary proton beams from a 130 MeV cyclotron impinging upon a suitable target. The species of interest is ejected from the target in ionic form, electrostatically accelerated, mass separated, and routed to a science chamber. Here, ions are neutralized by implantation in a thin foil, and extracted by thermal diffusion. A neutral vapor at room temperature is thus formed and trapped in a magneto-optical trap. Real-time fluorescence imaging and destructive absorption imaging provide information on the number of trapped atoms, their
30.08.2018
09:37 Arxiv.org PhysicsFuel Pellet Alignment in Heavy-Ion Inertial Fusion Reactor. (arXiv:1808.09671v1 [physics.plasm-ph])
In inertial confinement fusion, the scientific issues include the generation and transport of driver energy, the pellet design, the uniform target implosion physics, the realistic nuclear fusion reactor design, etc. In this paper, we present a pellet injection into a power reactor in heavy ion inertial fusion. We employ a magnetic correction method to reduce the pellet alignment error in heavy ion inertial fusion reactor chamber, including the gravity, the reactor gas drag force and the injection errors. We found that the magnetic correction device proposed in this paper is effective to construct a robust pellet injection system with a sufficiently small pellet alignment error.
28.08.2018
07:54 Arxiv.org PhysicsFluid simulations of plasma filaments in stellarator geometries with BSTING. (arXiv:1808.08899v1 [physics.plasm-ph])
Here we present first results simulating plasma filaments in non-axisymmetric geometries, using a fluid turbulence extension of the \boutxx~framework. This is made possible by the implementation of the Flux Coordinate Independent scheme for parallel derivatives, an extension of the metric tensor components which allows them to vary in three dimensions, and development of grid generation. Tests have been performed to confirm that the extension to three dimensional metric tensors does not compromise the accuracy and stability of the associated numerical operators. Recent changes to the FCI grid generator in \boutxx, including a curvilinear grid system which allows for potentially more efficient computation, are also presented. Initial simulations of seeded plasma filaments in a non-axisymmetric geometry are reported. We characterize filaments propagating in the closed-field-line region of a
07:54 Arxiv.org PhysicsLandau damping of Alfv\'enic modes in stellarators. (arXiv:1808.08862v1 [physics.plasm-ph])
It is found that the presence of the so-called non-axisymmetric resonances of wave-particle interaction in stellarators [which are associated with the lack of axial symmetry of the magnetic configuration, Kolesnichenko et al., Phys. Plasmas 9 (2002) 517] may have a strong stabilizing influence through Landau mechanism on the Toroidicity-induced Alfv\'en Eigenmodes (TAE) and isomon modes (Alfv\'enic modes with equal poloidal and toroidal mode numbers and frequencies in the continuum region) destabilized by the energetic ions. These resonances involve largest harmonics of the equilibrium magnetic field of stellarators and lead to absorption of the mode energy by thermal ions in medium pressure plasma, in which case the effect is large. On the other hand, at the high pressure attributed to, e.g., a Helias reactor, thermal ions can interact also with high frequency Alfv\'en gap modes
27.08.2018
19:39 Phys.orgArtificial intelligence project to help bring the power of the sun to Earth is picked for first U.S. exascale system
To capture and control the process of fusion that powers the sun and stars in facilities on Earth called tokamaks, scientists must confront disruptions that can halt the reactions and damage the doughnut-shaped devices. Now an artificial intelligence system under development at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) and Princeton University to predict and tame such disruptions has been selected as an Aurora Early Science project by the Argonne Leadership Computing Facility, a DOE Office of Science User Facility.
03:47 Arxiv.org CSDecision fusion with multiple spatial supports by conditional random fields. (arXiv:1808.08024v1 [eess.IV])
Classification of remotely sensed images into land cover or land use is highly dependent on geographical information at least at two levels. First, land cover classes are observed in a spatially smooth domain separated by sharp region boundaries. Second, land classes and observation scale are also tightly intertwined: they tend to be consistent within areas of homogeneous appearance, or regions, in the sense that all pixels within a roof should be classified as roof, independently on the spatial support used for the classification. In this paper, we follow these two observations and encode them as priors in an energy minimization framework based on conditional random fields (CRFs), where classification results obtained at pixel and region levels are probabilistically fused. The aim is to enforce the final maps to be consistent not only in their own spatial supports (pixel and region) but also
24.08.2018
16:29 Phys.orgPushing the plasma density limit
For decades, researchers have been exploring ways to replicate on Earth the physical process of fusion that occurs naturally in the sun and other stars. Confined by its own strong gravitational field, the sun's burning plasma is a sphere of fusing particles, producing the heat and light that makes life possible on earth. But the path to a creating a commercially viable fusion reactor, which would provide the world with a virtually endless source of clean energy, is filled with challenges.
23.08.2018
07:51 Arxiv.org MathPosition Locationing for Millimeter Wave Systems. (arXiv:1808.07094v1 [cs.IT])
The vast amount of spectrum available for millimeter wave (mmWave) wireless communication systems will support accurate real-time positioning concurrent with communication signaling. This paper demonstrates that accurate estimates of the position of an unknown node can be determined using estimates of time of arrival (ToA), angle of arrival (AoA), as well as data fusion or machine learning. Real-world data at 28 GHz and 73 GHz is used to show that AoA-based localization techniques will need to be augmented with other positioning techniques. The fusion of AoA-based positioning with received power measurements for RXs in an office which has dimensions of 35 m by 65.5 m is shown to provide location accuracies ranging from 16 cm to 3.25 m, indicating promise for accurate positioning capabilities in future networks. Received signal strength intensity (RSSI) based positioning techniques that
07:51 Arxiv.org PhysicsA generalized Grad-Shafranov equation with plasma flow under a conformal coordinate transformation. (arXiv:1808.07291v1 [physics.plasm-ph])
We employ a conformal mapping transformation to solve a generalized Grad-Shafranov equation with incompressible plasma flow of arbitrary direction and construct particular up-down asymmetric D-shaped and diverted tokamak equilibria. The proposed method can also be employed as an alternative quasi-analytic method to solving two dimensional elliptic partial differential equations.
07:51 Arxiv.org CSPosition Locationing for Millimeter Wave Systems. (arXiv:1808.07094v1 [cs.IT])
The vast amount of spectrum available for millimeter wave (mmWave) wireless communication systems will support accurate real-time positioning concurrent with communication signaling. This paper demonstrates that accurate estimates of the position of an unknown node can be determined using estimates of time of arrival (ToA), angle of arrival (AoA), as well as data fusion or machine learning. Real-world data at 28 GHz and 73 GHz is used to show that AoA-based localization techniques will need to be augmented with other positioning techniques. The fusion of AoA-based positioning with received power measurements for RXs in an office which has dimensions of 35 m by 65.5 m is shown to provide location accuracies ranging from 16 cm to 3.25 m, indicating promise for accurate positioning capabilities in future networks. Received signal strength intensity (RSSI) based positioning techniques that
22.08.2018
22:56 ScienceDaily.comSteady as she goes: Scientists tame damaging plasma instabilities in fusion facilities
In a set of recent experiments, scientists have tamed a damaging plasma instability in a way that could lead to the efficient and steady-state operation of ITER, the international tokamak experiment under construction in France to demonstrate the practicality of fusion power.
20:10 Phys.orgSteady as she goes: Scientists tame damaging plasma instabilities in fusion facilities
Before scientists can capture and recreate the fusion process that powers the sun and stars to produce virtually limitless energy on Earth, they must first learn to control the hot plasma gas that fuels fusion reactions. In a set of recent experiments, scientists have tamed a plasma instability in a way that could lead to the efficient and steady state operation of ITER, the international experiment under construction in France to demonstrate the feasibility of fusion power. Such continuous operation will be essential for future fusion devices.
03:32 Arxiv.org PhysicsGyrokinetic GENE simulations of DIII-D near-edge L-mode plasmas. (arXiv:1808.06607v1 [physics.plasm-ph])
We present gyrokinetic simulations with the GENE code addressing the near-edge region of an L-mode discharge in the DIII-D tokamak. At radial position $\rho=0.80$, we find that radial ion transport is nonlinearly quenched by a strong poloidal zonal flow with a clear Dimits shift. Simulations with the ion temperature gradient increased by $\sim40\%$ above the nominal value give electron and ion heat fluxes that are in simultaneous agreement with the experiment. This gradient increase is within the uncertainty of the Charge Exchange Recombination (CER) diagnostic measurements at the $1.6 \sigma$ level. Multi-scale simulations are carried out with realistic mass ratio and geometry for the first time in the near-edge. These suggest that highly unstable ion temperature gradient driven modes of the flux-matched ion-scale simulations strongly suppress electron-scale transport, such that ion-scale
21.08.2018
18:08 Phys.orgHigher plasma densities, more efficient tokamaks
When the density of the hot, ionized gas (known as a plasma) in a tokamak exceeds a certain limit, it usually leads to a rapid loss of heat and plasma currents. The currents are required to confine the plasma. Such events can seriously damage the tokamak. Before the disruption, scientists often observe large magnetic islands. Magnetic islands are thermally isolated, small "bubbles" of plasma. Recent investigations confirmed that scientists could use these islands to correctly predict the density limit. The team showed that when the island becomes large enough, the hot plasma core mixes with the cool plasma and causes the disruption. They can use this information to control the disruptions.
15.08.2018
08:24 Arxiv.org PhysicsTwo-Fluid Nonlinear Theory of Response of Tokamak Plasma to Resonant Magnetic Perturbation. (arXiv:1808.04482v1 [physics.plasm-ph])
A comprehensive two-fluid nonlinear theory of magnetic reconnection driven at a single, tearing-stable, rational surface embedded in an H-mode tokamak plasma is presented. The surface is assumed to be resonant with one of the dominant helical harmonics of an applied resonant magnetic perturbation (RMP). The theory described in this paper is highly relevant to the problem of understanding the physics of RMP-induced edge localized mode (ELM) suppression in tokamak plasmas.
11.08.2018
19:40 WhatReallyHappened.comUK nuclear fusion reactor could supply the grid with clean power
10.08.2018
08:11 Arxiv.org PhysicsDesign and measurement methods for a lithium vapor box similarity experiment. (arXiv:1808.02908v1 [physics.ins-det])
The lithium vapor box divertor is a concept for handling the extreme divertor heat fluxes in magnetic fusion devices. In a baffled slot divertor, plasma interacts with a dense cloud of Li vapor which radiates and cools the plasma, leading to recombination and detachment. Before testing on a tokamak the concept should be validated: we plan to study detachment and heat redistribution by a Li vapor cloud in laboratory experiments. Mass changes and temperatures are measured to validate a Direct Simulation Monte Carlo model of neutral Li. The initial experiment involves a 5 cm diameter steel box containing 10 g of Li held at 650 degrees C as vapor flows out a wide nozzle into a similarly-sized box at a lower temperature. Diagnosis is made challenging by the required material compatibility with lithium vapor. Vapor pressure a steep function of temperature, so to validate mass flow models to within
09.08.2018
17:04 Phys.orgDiamond capsules improve performance of laser fusion
Osaka University-led researchers demonstrated that the perturbation of laser imprinting on a capsule for nuclear fusion fuel made from stiff and heavy materials was mitigated. Using the latest chemical vapor deposition (CVD) method, they also produced high-precision diamond fuel capsules, a key technology applicable for fusion fuel.
08.08.2018
06:40 Arxiv.org CSLearning-Aided Physical Layer Authentication as an Intelligent Process. (arXiv:1808.02456v1 [cs.CR])
Performance of the existing physical layer authentication schemes could be severely affected by the imperfect estimates and variations of the communication link attributes used. The commonly adopted static hypothesis testing for physical layer authentication faces significant challenges in time-varying communication channels due to the changing propagation and interference conditions, which are typically unknown at the design stage. To circumvent this impediment, we propose an adaptive physical layer authentication scheme based on machine-learning as an intelligent process to learn and utilize the complex and time-varying environment, and hence to improve the reliability and robustness of physical layer authentication. Explicitly, a physical layer attribute fusion model based on a kernel machine is designed for dealing with multiple attributes without requiring the knowledge of their
07.08.2018
09:23 Arxiv.org PhysicsIntrinsic rotation driven by turbulent acceleration. (arXiv:1808.01429v1 [physics.plasm-ph])
Differential rotation is induced in tokamak plasmas when an underlying symmetry of the governing gyrokinetic-Maxwell system of equations is broken. One such symmetry-breaking mechanism is considered here: the turbulent acceleration of particles along the mean magnetic field. This effect, often referred to as the `parallel nonlinearity', has been implemented in the $\delta f$ gyrokinetic code $\texttt{stella}$ and used to study the dependence of turbulent momentum transport on the plasma size and on the strength of the turbulence drive. For JET-like parameters with a wide range of driving temperature gradients, the momentum transport induced by the inclusion of turbulent acceleration is similar to or smaller than the ratio of the ion Larmor radius to the plasma minor radius. This low level of momentum transport is explained by demonstrating an additional symmetry that prohibits momentum
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https://socratic.org/questions/what-units-can-measure-weight#618285
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Chemistry
Topics
# What units can measure weight?
May 22, 2018
Technically, Newtons, $\text{N}$, or a ${\text{kg"cdot"m/s}}^{2}$.
#### Explanation:
A weight is a force.
Newtons is a unit of force.
Mass in a gravitational field creates a force, but mass by itself is not a force.
${\vec{F}}_{g} = m \vec{g}$, ${\text{ "vecg = -"9.80665 m/s}}^{2}$
Mass is often used (technically incorrectly) as an indirect measure of weight. Mass is a measure of the amount of matter in a substance, not a measure of force.
Mass is more accurately a measure of inertia, $I \propto m {r}^{2}$ (where $r$ is the distance to the axis of rotation).
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http://openstudy.com/updates/55f990e2e4b08f8c5b46e5b9
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## KJ4UTS one year ago The profit function for a firm making DVDs is P(x) = 88x - x^2 -1200. Find the number of DVDs at which maximum profit is achieved, and find the maximum profit. Please explain. Thank you! Delete Cancel Submit
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1. KJ4UTS
• one year ago
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@peachpi
2. some.random.cool.kid
• one year ago
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@Nnesha
3. anonymous
• one year ago
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Is x the number of dvds?
4. KJ4UTS
• one year ago
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Yeah I think so.
5. anonymous
• one year ago
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It looks like this is asking for the vertex of the parabola. $$x=-\frac{b}{2a}$$ is the amount of dvd where profit is max $$P(-\frac{b}{2a})$$ is the maximum profit
6. KJ4UTS
• one year ago
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Do I plug in the 88 and -1200 in that formula?
7. anonymous
• one year ago
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-b/(2a) = -88/(2*-1)
8. anonymous
• one year ago
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a is the coefficient of x² b is the coefficient of x c is the constant It helps to write it in descending order
9. KJ4UTS
• one year ago
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44 so that would be the max number of dvds 88(44)-44^2-1200=\$736 (the max profit)
10. KJ4UTS
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@peachpi thank you :)
11. anonymous
• one year ago
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that's what I got :) you're welcome
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http://crypto.stackexchange.com/questions/19620/how-to-calculate-the-entropy-of-passwords
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# How to calculate the entropy of passwords? [duplicate]
I dont quite understand how the entropy is calculated in the cartoon assuming they are calculate correctly. But in general, I dont have much idea about how password entropy is calculated.
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## marked as duplicate by otus, fgrieu, DrLecter, Gilles, hunterOct 14 '14 at 14:23
First of all: Entropy is a property of the process generating a password, not a property of an individual password.
Apart from that, the basic idea is the following: Say you have the password aeLuboo0 that contains lower-case chars, upper-case chars and numbers. Then under the assumption that you have choosen every character uniformely from all possible characters, there are in total
$$(26 + 26 + 10)^8 = 218340105584896$$
many passwords that can be generated in the same way as your concrete password has been generated. The entropy in bits is now the number of bits you need to have approximately the same number of possible bit-combinations. That is:
$$\log_2((26 + 26 +10)^8) = 47.633570483095$$
Hence the assumed process that generated your password aeLuboo0 can generated as many different equal likely passwords, as different numbers can be represented by $47.63$ bits. The entropy of the password can be assumed to be at $48$ bits.
The cartoon has the example of a word, that has been taken from a dictionary and then mutated to get the actual password. The idea of entropy is the same again (heavily simplified): Guess the number of different words your theoretical source dictionary and multiply it by the number of possible mutations the get a total count of passwords that can be generated in this way. Now find the $\log_2$ of this count to approximate the entropy.
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https://www.physicsforums.com/threads/probability-two-unfair-dice.677137/
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# Probability - two unfair dice
1. Mar 8, 2013
### Saitama
1. The problem statement, all variables and given/known data
(see attachment)
2. Relevant equations
3. The attempt at a solution
The sum of the probabilities of each number on the dice is 1, i.e
$$\frac{1}{6}+\frac{1}{6}+\frac{1}{9}+x+\frac{2}{9}+y=1$$
where x and y are the probabilities of number 4 and 6 respectively. Solving,
$$x+y=\frac{1}{3}$$
The probability that the two dice shows same number is
$$\left(\frac{1}{6} \right)^2+\left(\frac{1}{6} \right)^2+\left(\frac{1}{9} \right)^2+x^2+\left(\frac{2}{9} \right)^2+y^2=\left(\frac{2}{3} \right)^4$$
Solving, $$x^2+y^2=\frac{13}{18}$$
Rewriting $x^2+y^2$ as $(x+y)^2-2xy$ and substituting the value of $x+y$,
$$2xy=\frac{-11}{18}$$
For the sum of two resulting numbers to be 10, there are three possible cases. The first shows 4 and the second shows 6 or (4,6). The other cases are (5,5) and (6,4).
The probability that the sum of the two resulting numbers is 10 can be given by the expression:
$$2xy+\left(\frac{2}{9} \right)^2$$
Substituting the value of $2xy$, I get a negative answer.
Any help is appreciated. Thanks!
#### Attached Files:
• ###### probability.png
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Last edited: Mar 8, 2013
2. Mar 8, 2013
### Dick
I think you are just messing up the arithmetic. I don't get x^2+y^2=13/18. Check it.
3. Mar 8, 2013
### Saitama
Oh yes, I missed a factor of 9 in the denominator.
Thanks Dick!
Draft saved Draft deleted
Similar Discussions: Probability - two unfair dice
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https://ai.stackexchange.com/questions/17231/how-to-understand-the-concept-of-self-supervised-learning-in-ai
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# How to understand the concept of self-supervised learning in AI?
I am new to self-supervised learning and it all seems a little magical at the moment.
The only way I can get an intuitive understanding is to assume that, for real-world problems, features are still embedded at a per-object level.
For example, to detect cats in unseen images, my self-supervised network would still have to be composed exclusively of cats.
So, if I had 100 images of cats and 100 images of dogs, then I thought self-supervised approaches would learn the features of the images. For example, if an image is rotated 90 degrees, it learns what was in the image that was rotated 90 degrees. However, if I wanted to classify just cats using this representation, then I wouldn't be able to do so without separating out what makes a cat a cat and a dog a dog.
Is my assumption correct?
• This question is very related to this one, but you're specifically asking 1. "Why SSL really works?" and 2. "What is the relationship between the downstream task and the data used to learn representations?", if I understand correctly. Can you confirm that? If those are your questions, none of the current answers below seem to really address them. They only state what SSL is, which you already know, apparently.
– nbro
Nov 20, 2020 at 2:44
I don't think your interpretation is correct. Take images as example.
• Supervised Learning
e.g. classification (maybe use CNN with a L2 loss function)
Assume you have many images with different labels. You wish to find a function to approximate the function $$y=f(x)$$ given a lot of $$(\hat x, \hat y)$$ sample pairs.
• Unsupervised Learning
e.g. clustering (maybe use k-means)
Assume you have many images, but we don't have the labels or we just want to see if there's a way to categorize them into different categories. So we cluster the images by some characteristic that isn't pre-defined.
• Self-Supervised Learning
e.g. super resolution (maybe use CNN with a L2 loss function)
You have many high resolution images without labels, but, your target is to train a model to up sample a low resolution image. So you can have the high resolution images as target, and down size the image to be the input, and try to train the image pairs. So the target is not some manually tagged labels, but generated directly from the data.
• The contents of this answer seem to be correct, but maybe you should address the part of the OP "For example, to detect cats in unseen images, my self-supervised network would still have to be composed exclusively of cats...". The OP already seemed to know what SSL is. They wanted to understand why it really works and the relationship between the downstream task and the pre-text task (and data), if I understood correctly. Your answer doesn't address this.
– nbro
Nov 20, 2020 at 2:48
Andrew Zisserman, who is a pioneer in the field of self-supervised learning, described self-supervised learning in a talk at ICML as:
Self-supervised Learning is a form of unsupervised learning where the data provides the supervision. In general, we withhold some part of the data and task the network with predicting it. The network is forced to learn what we really care about e.g. a semantic representation, in order to solve it.
Thus, self-supervised is a subset of unsupervised learning, where you generate the labels from the given data itself. There are a few patterns of research being done for self-supervised learning:
1. Reconstruction:
In this, researchers have set up pretext tasks as predicting the color image from gray-scale image (Image Colorization), predicting the high-resolution image from the low-resolution version (Image Super-resolution) and removing some part of the image and trying to predict it (Image Inpainting).
2. Common Sense Reasoning:
You could take patches of 3x3 images and shuffle the patches and ask the network to predict the correct order (Jigsaw puzzle).
Similarly, you could take the center patch and some random patch and train model to predict where the random patch is located in relation to the center patch (context prediction).
There is another approach where you randomly rotate image into {0, 90, 180, 270} degrees and ask the model to predict the rotation angle applied (Geometric Transformation Recognition).
3. Clustering:
You could cluster the images into K categories and treat those clusters as labels. Then, a model can be trained on those clusters and you get representations. You can again repeat clustering and model training for few epochs. Papers for these include: DeepCluster and Self-Labelling.
4. Contrastive Learning:
In this paradigm, augmentations of the image is taken and the task is to bring two augmentations of the same images near while making the distance between this image and some other random image far. Papers for these include: SimCLR and PIRL.
• The contents of this answer seem to be correct, but maybe you should address the part of the OP "For example, to detect cats in unseen images, my self-supervised network would still have to be composed exclusively of cats...". The OP already seemed to know what SSL is. They wanted to understand why it really works and the relationship between the downstream task and the pre-text task (and data), if I understood correctly. Your answer doesn't address this.
– nbro
Nov 20, 2020 at 2:48
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https://www.bestdaixie.com/python%E4%BB%A3%E5%86%99-project-2-reinforcement-learning/
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# BEST代写-线上编程学术专家
Best代写-最专业靠谱代写IT | CS | 留学生作业 | 编程代写Java | Python |C/C++ | PHP | Matlab | Assignment Project Homework代写
# 本次美国代写是Python强化学习的一个assignment
### Introduction
In this project, you will implement value iteration and Q-learning. You will test your agents first on Gridworld (from class), then apply them to a simulated robot controller (Crawler) and Pacman.
Like Project 1, this project includes an autograder for you to grade your solutions on your machine. This can be run on all questions with the command:
python autograder.py
It can be run for one particular question, such as q2, by:
python autograder.py -q q2
It can be run for one particular test by commands of the form:
python autograder.py -t test_cases/q2/1-bridge-grid
Files you’ll edit: valueIterationAgents.py A value iteration agent for solving known MDPs. qlearningAgents.py Q-learning agents for Gridworld, Crawler and Pacman. analysis.py A file to put your answers to questions given in the project. Files you should read but NOT edit: mdp.py Defines methods on general MDPs. learningAgents.py Defines the base classes ValueEstimationAgent and QLearningAgent, which your agents will extend. util.py Utilities, including util.Counter, which is particularly useful for Q-learners. gridworld.py The Gridworld implementation. featureExtractors.py Classes for extracting features on (state,action) pairs. Used for the approximate Q-learning agent (in qlearningAgents.py). Files you can ignore: environment.py Abstract class for general reinforcement learning environments. Used by gridworld.py. graphicsGridworldDisplay.py Gridworld graphical display. graphicsUtils.py Graphics utilities. textGridworldDisplay.py Plug-in for the Gridworld text interface. crawler.py The crawler code and test harness. You will run this but not edit it. graphicsCrawlerDisplay.py GUI for the crawler robot. autograder.py Project autograder testParser.py Parses autograder test and solution files testClasses.py General autograding test classes test_cases/ Directory containing the test cases for each question reinforcementTestClasses.py Project 2 specific autograding test classes
Files to Edit and Submit: You will fill in portions of valueIterationAgents.pyqlearningAgents.py, and analysis.py during the assignment. You should submit these files with your code and comments. Please do not change the other files in this distribution or submit any of our original files other than these files.
Evaluation: Your code will be autograded for technical correctness. Please do not change the names of any provided functions or classes within the code, or you will wreak havoc on the autograder.
Academic Dishonesty: We will be checking your code against other submissions in the class for logical redundancy. If you copy someone else’s code and submit it with minor changes, we will know. These cheat detectors are quite hard to fool, so please don’t try. We trust you all to submit your own work only; please don’t let us down. If you do, we will pursue the strongest consequences available to us.
Getting Help: You are not alone! If you find yourself stuck on something, contact the course staff for help. Office hours and Piazza are there for your support; please use them. If you can’t make our office hours, let us know and we will schedule more. We want these projects to be rewarding and instructional, not frustrating and demoralizing. But, we don’t know when or how to help unless you ask.
### MDPs
To get started, run Gridworld in manual control mode, which uses the arrow keys:
python gridworld.py -m
You will see the two-exit layout from class. The blue dot is the agent. Note that when you press up, the agent only actually moves north 80% of the time. Such is the life of a Gridworld agent!
You can control many aspects of the simulation. A full list of options is available by running:
python gridworld.py -h
The default agent moves randomly
python gridworld.py -g MazeGrid
You should see the random agent bounce around the grid until it happens upon an exit. Not the finest hour for an AI agent.
Note: The Gridworld MDP is such that you first must enter a pre-terminal state (the double boxes shown in the GUI) and then take the special ‘exit’ action before the episode actually ends (in the true terminal state called TERMINAL_STATE, which is not shown in the GUI). If you run an episode manually, your total return may be less than you expected, due to the discount rate (-d to change; 0.9 by default).
Look at the console output that accompanies the graphical output (or use -t for all text). You will be told about each transition the agent experiences (to turn this off, use -q).
As in Pacman, positions are represented by (x,y) Cartesian coordinates and any arrays are indexed by [x][y], with 'north' being the direction of increasing y, etc. By default, most transitions will receive a reward of zero, though you can change this with the living reward option (-r).
### Question 1 (6 points): Value Iteration
Write a value iteration agent in ValueIterationAgent, which has been partially specified for you in valueIterationAgents.py. Your value iteration agent is an offline planner, not a reinforcement learning agent, and so the relevant training option is the number of iterations of value iteration it should run (option -i) in its initial planning phase. ValueIterationAgent takes an MDP on construction and runs value iteration for the specified number of iterations before the constructor returns.
Value iteration computes k-step estimates of the optimal values, Vk. In addition to running value iteration, implement the following methods for ValueIterationAgent using Vk.
• computeActionFromValues(state) computes the best action according to the value function given by self.values.
• computeQValueFromValues(state, action) returns the Q-value of the (state, action) pair given by the value function given by self.values.
These quantities are all displayed in the GUI: values are numbers in squares, Q-values are numbers in square quarters, and policies are arrows out from each square.
Important: Use the “batch” version of value iteration where each vector Vk is computed from a fixed vector Vk-1 (like in lecture), not the “online” version where one single weight vector is updated in place. This means that when a state’s value is updated in iteration k based on the values of its successor states, the successor state values used in the value update computation should be those from iteration k-1 (even if some of the successor states had already been updated in iteration k). The difference is discussed in Sutton & Barto in the 6th paragraph of chapter 4.1.
Note: A policy synthesized from values of depth k (which reflect the next k rewards) will actually reflect the next k+1 rewards (i.e. you return πk+1πk+1). Similarly, the Q-values will also reflect one more reward than the values (i.e. you return Qk+1).
You should return the synthesized policy πk+1πk+1.
Hint: Use the util.Counter class in util.py, which is a dictionary with a default value of zero. Methods such as totalCount should simplify your code. However, be careful with argMax: the actual argmax you want may be a key not in the counter!
Note: Make sure to handle the case when a state has no available actions in an MDP (think about what this means for future rewards).
python autograder.py -q q1
The following command loads your ValueIterationAgent, which will compute a policy and execute it 10 times. Press a key to cycle through values, Q-values, and the simulation. You should find that the value of the start state (V(start), which you can read off of the GUI) and the empirical resulting average reward (printed after the 10 rounds of execution finish) are quite close.
python gridworld.py -a value -i 100 -k 10
Hint: On the default BookGrid, running value iteration for 5 iterations should give you this output:
python gridworld.py -a value -i 5
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https://www.physicsforums.com/threads/tention-and-moments.809189/
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# Tention and Moments
Tags:
1. Apr 18, 2015
### ryanuser
1. The problem statement, all variables and given/known data
The problem is question 4) iii) B) found in the attachment below.
2. Relevant equations
• sum of c.w moments=sum of anti c.w moments.
• moment of a force about a point= force x perpendicular distance between the line of action of the force and the point.
3. The attempt at a solution
A full attemp is included as second attachment below. (Note the correct answer is 172.69N not 302.22N I calculated.
Why???? How???
Thanks
#### Attached Files:
File size:
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Views:
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• ###### image.jpg
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26.5 KB
Views:
91
2. Apr 18, 2015
### BvU
Hello RU,
by now you should be familiar with the workings of PF and know the guidelines.
Please state the problem by rephrasing it clearly and concisely. List the known/unknown variables.
Helps me and helps you too.
Equations are like $\Sigma\vec\tau = 0$.
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https://dml.cz/handle/10338.dmlcz/128435
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# Article
Full entry | PDF (0.3 MB)
References:
[F] W. G. Fleissner: Applications of Stationary sets in Topology. Surveys in General Topology, Academic Press, 1980, pp. 163–193. MR 0564102 | Zbl 0457.54005
[J] T. Jeck: Set Theory. Academic Press, 1978.
[$\nu$DL] E. K. Van Douwen and D. J. Lutzer: On the Classification of Stationary Sets. Michigan Math. J. 26 (1979), 47–64. DOI 10.1307/mmj/1029002162 | MR 0514960
Partner of
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http://scitation.aip.org/content/aip/journal/pop/17/4/10.1063/1.3394702
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• journal/journal.article
• aip/pop
• /content/aip/journal/pop/17/4/10.1063/1.3394702
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1887
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Nonlinear simulation of toroidal Alfvén eigenmode with source and sink
USD
10.1063/1.3394702
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Affiliations:
1 Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
Phys. Plasmas 17, 042309 (2010)
/content/aip/journal/pop/17/4/10.1063/1.3394702
http://aip.metastore.ingenta.com/content/aip/journal/pop/17/4/10.1063/1.3394702
View: Figures
## Figures
FIG. 1.
The contour plot of for the baseline case.
FIG. 2.
The time evolution of the mode amplitude with only pitch angle scattering at different collision rates. From the top to the bottom, the collision rates are , , , , and .
FIG. 3.
The nonlinear saturation level of the mode amplitude as a function of collision rate in the presence of pitch angle scattering only.
FIG. 4.
The time evolution of the mode amplitude with only slowing down process at different slowing down rates. From top to bottom, the slowing down rates are , , , and .
FIG. 5.
The nonlinear saturation level of the mode amplitude as a function of collision rate in the presence of slowing down only.
FIG. 6.
The contour plots of the as a function of toroidal angular momentum and energy for fixed . The right plot is for collisionless condition and the left plot is for slowing down only with slowing down rate .
FIG. 7.
The contour plot of the mode amplitude as a function of the mode frequency and time for slowing down case. The slowing down rate is .
FIG. 8.
The time evolution of the mode amplitude with both pitch angle scattering and slowing down at different collision rates. From top to bottom, the slowing down rates are , , , , and .
FIG. 9.
The nonlinear saturation level of the mode amplitude as a function of collision rate in the presence of both pitch angle scattering and slowing down.
FIG. 10.
The fast oscillation frequency versus the nonlinear saturation level of the mode amplitude.
FIG. 11.
The time evolution of the mode amplitude for different parameter regimes at . From top to bottom, the first line is for the case with the combination of both slowing down and pitch angle scattering, the second line is for the case with slowing down, and the third line is for the case with pitch angle scattering.
FIG. 12.
The time evolution of the mode amplitude for different parameter regimes at . The dotted line is for collisionless case, the dashed line is for the case with the combination of both slowing down and pitch angle scattering, the solid line is for the case with slowing down, and the dashed-dotted line is for the case with pitch angle scattering.
FIG. 13.
The distribution function as a function of toroidal angular momentum for fixed and with three cases, collisionless, pitch angle scattering only, slowing down only. The slowing down rate .
FIG. 14.
The time evolution of the mode amplitude for the near-marginal instability case. No collisions are present in this case.
FIG. 15.
The distribution function as a function of toroidal angular momentum for fixed and with near-marginal instability at three times, the dashed line corresponds to the first nonlinear drop at , the solid line corresponds to the first nonlinear rise at , and the dashed-dotted line corresponds to the second nonlinear drop at .
FIG. 16.
The contour plot of the mode amplitude as a function of the mode frequency and time for near-marginal instability case. No collisions are present in this case.
FIG. 17.
The time evolution of the mode amplitude for different numbers of particles with slowing down only , the total number particles used in the dashed line is four times larger than that used in the solid line.
FIG. 18.
The time evolution of the mode amplitude for different time steps with both pitch angle scattering and slowing down , the time step used in the solid curve is 1/4 of that used in the dashed curve.
/content/aip/journal/pop/17/4/10.1063/1.3394702
2010-04-29
2014-04-17
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• 1.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Macromolecular crowding extended to a heptameric system: the co-chaperonin protein 102011In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 50, no 14, p. 3034-3044Article in journal (Refereed)
Experiments on monomeric proteins have shown that macromolecular crowding can stabilize toward heat perturbation and also modulate native-state structure. To assess the effects of macromolecular crowding on unfolding of an oligomeric protein, we here tested the effects of the synthetic crowding agent Ficoll 70 on human cpn10 (GroES in E. coli), a heptameric protein consisting of seven identical β-barrel subunits assembling into a ring. Using far-UV circular dichroism (CD), tyrosine fluorescence, nuclear magnetic resonance (NMR), and cross-linking experiments, we investigated thermal and chemical stability, as well as the heptamer-monomer dissociation constant, without and with crowding agent. We find that crowding shifts the heptamer-monomer equilibrium constant in the direction of the heptamer. The cpn10 heptamer is both thermally and thermodynamically stabilized in 300 mg/mL Ficoll 70 as compared to regular buffer conditions. Kinetic unfolding experiments show that the increased stability in crowded conditions, in part, is explained by slower unfolding rates. A thermodynamic cycle reveals that in presence of 300 mg/mL Ficoll the thermodynamic stability of each cpn10 monomer increases by over 30%, whereas the interfaces are stabilized by less than 10%. We also introduce a new approach to analyze the spectroscopic data that makes use of multiple wavelengths: this provides robust error estimates of thermodynamic parameters.
• 2. Borgström, Johan
Umeå University, Faculty of Science and Technology, Chemistry.
Liquid crystallinity versus gelation of kappa-carrageenan in mixed salts: effects of molecular weight, salt composition, and ionic strength1998In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 14, no 17, p. 4935-44Article in journal (Refereed)
The recently discovered isotropic/nematic phase transition in kappa-carrageenan was further examined by macroscopic observations and by NMR. A state diagram, which is the equivalent of a phase diagram but including also nonequilibrium states (in our case a gel), was established in the mixed salt solutions of NaI/CsI where the competition between phase separation and gelation could be studied. The phase boundaries of the nematic phase depended on molecular weight and ionic strength qualitatively as expected for a charged rigid polymer. From these data the persistence length of the kappa-carrageenan helix was estimated as 60-90 nm. The volume fraction of the nematic phase depended sensitively on the overall helical content. In coexisting phases, the helical content was larger in the nematic than in the isotropic phase.
• 3.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Synthesis of poly(N-[tris(hydroxymethyl)methyl]acrylamide) functionalized porous silica for application in hydrophilic interaction chromatography2012In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 35, no 23, p. 3257-3269Article in journal (Refereed)
Porous silica coated by a highly hydrophilic and nonionic tentacle-type polymeric layer was synthesized by free radical "grafting from" polymerization of N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]-2-propenamide (TRIS-acrylamide) in partly aqueous solutions. The radical initiator sites were incorporated on the silica surfaces via a two-step reaction comprising thionyl chloride activation and subsequent reaction with tert-butyl hydroperoxide. The surface-bound tert-butylperoxy groups were then used as thermally triggered initiators for graft polymerization of TRIS-acrylamide. The synthesized materials were characterized by diffusive reflectance Fourier transform infrared specotroscopy, X-ray photoelectron spectroscopy, and CHN elemental analysis. Photon correlation spectroscopy was used to determine changes in ζ-potentials resulting from grafting, (29) Si magic angle spinning nuclear magnetic resonance spectroscopy (MAS-NMR) spectroscopy was used to assess the ratio of silanol to siloxane groups in the substrate and the grafted material, and the changes in surface area and mesopore distribution were determined by nitrogen cryosorption. Chromatographic evaluation in hydrophilic interaction chromatography (HILIC) mode showed that the materials were suitable for use as stationary phases, featuring good separation efficiency, a comparatively high retention, and a selectivity that differed from most commercially available HILIC phases. A comparison of this neutral phase with a previously reported N-(2-hydroxypropyl)-linked TRIS-type hydrophilic tentacle phase with weak anion exchange functionality revealed substantial differences in retention patterns.
• 4.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Dynamical and Structural Alterations withing Lipid-Protein Assemblies Control Apoptotic Pore Formation - A Solid State NMR Study2016In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 110, no 3, p. 59A-60AArticle in journal (Other academic)
• 5.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Oxidatively stressed mitochondria-mimicking membranes: a molecular insight into their organization during apoptosis2018In: Biochimica et Biophysica Acta - Biomembranes, ISSN 0005-2736, E-ISSN 1879-2642, Vol. 1860, no 12, p. 2644-2654Article in journal (Refereed)
Mitochondria are crucially involved in the removal of eukaryotic cells by the intrinsic pathway of programmed cell death (apoptosis). The mitochondrion's outer membrane (MOM) is the platform where this pathway takes place. Upon oxidative stress triggering apoptotic action, the MOM undergoes permeabilization and release of cytochrome c, ultimately causing cell death. This membrane perforation is regulated not only by opposing members of the Bcl-2 protein family meeting at the MOM but also actively the membrane itself. Upon oxidative damage, the membrane undergoes severe reorganization causing an increase in cell death-causing apoptotic Bcl-2 proteins. To understand the active role of MOM, we provided a detailed molecular view of its structural and dynamic reorganization upon oxidative stress by solid-state C-13 MAS NMR (magic angle spinning nuclear magnetic resonance) accompanied by calorimetric studies. By focusing on MOM-like vesicles doped with oxidized lipid species, direct polarization C-13 MAS NMR provided a quantitative overview and identification of all lipid moieties across the membrane. H-1-C-1(3) cross polarization and insensitive nuclei enhanced by polarization transfer MAS NMR generated a dynamic - mobile versus restricted - membrane profile. Oxidized phospholipids significantly perturb the structural membrane organization and increase membrane dynamics. These perturbations are not uniformly distributed as the hydrophobic core is reflecting the melting of lipid chains and increase in molecular disorder directly, whereas the interface and headgroup region undergo complex dynamical changes, reflecting increased intra-molecular flexibility of these moieties. These changes are potentially crucial in augmenting pro-apoptotic action of proteins like Bax.
• 6.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Apoptotic Bax at Oxidatively Stressed Mitochondrial Membranes: Lipid Dynamics and Permeabilization2017In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 112, no 10, p. 2147-2158Article in journal (Refereed)
Mitochondria are crucial compartments of eukaryotic cells because they function as the cellular power plant and play a central role in the early stages of programmed cell death (apoptosis). To avoid undesired cell death, this apoptotic pathway is tightly regulated by members of the Bcl-2 protein family, which interact on the external surface of the mitochondria, i.e., the mitochondrial outer membrane (MOM), and modulate its permeability to apoptotic factors, controlling their release into the cytosol. A growing body of evidence suggests that the MOM lipids play active roles in this permeabilization process. In particular, oxidized phospholipids (OxPls) formed under intracellular stress seem to directly induce apoptotic activity at the MOM. Here we show that the process of MOM pore formation is sensitive to the type of OxPls species that are generated. We created MOM-mimicking liposome systems, which resemble the cellular situation before apoptosis and upon triggering of oxidative stress conditions. These vesicles were studied using P-31 solid-state magic-angle-spinning nuclear magnetic resonance spectroscopy and differential scanning calorimetry, together with dye leakage assays. Direct polarization and cross-polarization nuclear magnetic resonance experiments enabled us to probe the heterogeneity of these membranes and their associated molecular dynamics. The addition of apoptotic Bax protein to OxPls-containing vesicles drastically changed the membranes' dynamic behavior, almost completely negating the previously observed effect of temperature on the lipids' molecular dynamics and inducing an ordering effect that led to more cooperative membrane melting. Our results support the hypothesis that the mitochondrion-specific lipid cardiolipin functions as a first contact site for Bax during its translocation to the MOM in the onset of apoptosis. In addition, dye leakage assays revealed that different OxPls species in the MOM-mimicking vesicles can have opposing effects on Bax pore formation.
• 7.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Correlated/non-correlated ion dynamics of charge-neutral ion couples: the origin of ionicity in ionic liquids2017In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, no 7, p. 4975-4988Article in journal (Refereed)
Proton/Fluoride spin-lattice ($T_1$) nuclear magnetic relaxation dispersion (NMRD) measurements of 1-butyl-3-methyl-$1H$-imidazolium hexa-fluorophosphate, [$C_4mim][PF_6]$, have been carried out using high field spectrometers and fast-field-cycling instrument at proton Larmor frequencies ranging from 10kHz to 40 MHz, at different temperatures. The NMRD profiles are interpreted by means of a simple relaxation model based on the inter- and intra-ionic dipole-dipole relaxation mechanism. Using an atomic molecular-ion dynamic simulation at 323 K the relevant spin dipole-dipole(DD) correlation functions are calculated. The results indicate the NMRD profiles can be rationalized using intra- and inter-ionic spin DD interactions, however, both are mainly modulated by ionic reorientation because of temporary correlations with cations, where modulation by translational diffusion plays a minor role. Reorientational dynamics of charge-neutral ion couples (i.e. $[C_4mim]^{...}[PF_6]$) and $[C_4mim]^{+}$ ions are in the nano-second (ns) time range whereas the reorientation of $[PF_6]{^-}$ is characterized by a reorientational correlation time in the pico-second (ps) regime. Based on the NMRD profiles we conclude the main relaxation mechanism for $[PF_6]{^-}$ is, due to fast internal reorientational motion, a partially averaged F-F intra and a F-H inter-ionic DD coupling as the anion resides in close proximity to its temporary oppositely charged cation partner. The F-$T_1$- NMRD data display a ns dispersions which is interpreted as being due to correlated reorientational modulations resultant from H-containing charge-neutral ion couple $[C_4mim]^{...}[PF_6]$. The analysis of ionicity is based on the free anion fraction, $f$ and it increase with temperature with $f$ $\rightarrow$ 1 at the highest temperatures investigated. The fraction is obtained from the H-F NMRD profiles as correlated-non-correlated dynamics of the ions. The analysis of $T_1$ relaxation rates of C, H, F and P at high fields cannot generally give the fraction of ion but are consistent with the interpretation based on the NMRD profiles with relaxation contributions due to DD-intra and -inter, CSA-intra (and -inter for C), including spin rotation for P. The investigation has led to a description of the mechanics governing ion transport in the title ionic liquid via identification of transient correlated/non-correlated ion dynamics.
• 8. Drotz, Stina Harrysson
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
Both catabolic and anabolic heterotrophic microbial activity proceed in frozen soils2010In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 107, no 49, p. 21046-21051Article in journal (Refereed)
A large proportion of the global soil carbon pool is stored in soils of high-latitude ecosystems in which microbial processes and production of greenhouse gases proceed during the winter months. It has been suggested that microorganisms have limited ability to sequester substrates at temperatures around and below 0 °C and that a metabolic shift to dominance of catabolic processes occurs around these temperatures. However, there are contrary indications that anabolic processes can proceed, because microbial growth has been observed at far lower temperatures. Therefore, we investigated the utilization of the microbial substrate under unfrozen and frozen conditions in a boreal forest soil across a temperature range from -9 °C to +9 °C, by using gas chromatography-isotopic ratio mass spectrometry and (13)C magic-angle spinning NMR spectroscopy to determine microbial turnover and incorporation of (13)C-labeled glucose. Our results conclusively demonstrate that the soil microorganisms maintain both catabolic (CO(2) production) and anabolic (biomass synthesis) processes under frozen conditions and that no significant differences in carbon allocation from [(13)C]glucose into [(13)C]CO(2) and cell organic (13)C-compounds occurred between +9 °C and -4 °C. The only significant metabolic changes detected were increased fluidity of the cell membranes synthesized at frozen conditions and increased production of glycerol in the frozen samples. The finding that the processes in frozen soil are similar to those in unfrozen soil has important implications for our general understanding and conceptualization of soil carbon dynamics in high-latitude ecosystems.
• 9.
Department of Forest Ecology & Management, Swedish University of Agricultural Sciences. Umeå.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Department of Forest Ecology & Management, Swedish University of Agricultural Sciences. Umeå. Department of Forest Ecology & Management, Swedish University of Agricultural Sciences. Umeå.
Effects of soil organic matter composition on unfrozen water content and heterotrophic CO2 production of frozen soils2010In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 74, no 8, p. 2281-90Article in journal (Refereed)
Several recent studies have highlighted the importance of soil organic matter (SOM) mineralization at high latitudes during winter for ecosystem carbon (C) balances, and the ability of the soil to retain unfrozen water at sub-zero temperatures has been shown to be a major determinant of C mineralization rates. Further, SOM is believed to strongly influence the liquid water contents in frozen surface layers of boreal forest soils and tundra, but the mechanisms and specific factors involved are currently unknown. Here we evaluate the effects of the chemical composition of SUM on the amount of unfrozen water, the pore size equivalents in which unfrozen water can exist, and the microbial heterotrophic activity at sub-zero temperatures in boreal forest soils. To do this, we have characterized the chemical composition of SUM in forest soil samples (surface O-horizons) using solid state CP-MAS (cross polarization magic angle spinning) NMR spectroscopy. The acquired information was then used to elucidate the extent to which different fractions of SUM can explain the observed variations in unfrozen water content, pore size equivalents, and biogenic CO2 production rates in the examined soil samples under frozen conditions (-4 degrees C). The data evaluation was done by the use of principal component analysis (PCA) and projections to latent structures by means of partial least square (PLS). We conclude that aromatic, O-aromatic, methoxy/N-alkyl and alkyl C are the major SOM components affecting frozen boreal forest soil's ability to retain unfrozen water and sustain heterotrophic activity (95% confidence level). Our results reveal that solid carbohydrates have a significant negative impact (95% confidence level) on CO2 production in frozen boreal spruce forest soils, in contrast to the positive effects of carbohydrate polymers during unfrozen conditions. We conclude that the hierarchy of environmental factors controlling SOM mineralization changes as soils freeze. The effect of SUM composition on pore size distribution and unfrozen water content has a superior influence on SUM mineralization and hence on heterotrophic CO2 production of frozen soils. (C) 2010 Elsevier Ltd. All rights reserved.
• 10.
Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden. Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden. Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden.
Temperature response of litter and soil organic matter decomposition is determined by chemical composition of organic material2013In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 19, no 12, p. 3858-3871Article in journal (Refereed)
The global soil carbon pool is approximately three times larger than the contemporary atmospheric pool, therefore even minor changes to its integrity may have major implications for atmospheric CO2 concentrations. While theory predicts that the chemical composition of organic matter should constitute a master control on the temperature response of its decomposition, this relationship has not yet been fully demonstrated. We used laboratory incubations of forest soil organic matter (SOM) and fresh litter material together with NMR spectroscopy to make this connection between organic chemical composition and temperature sensitivity of decomposition. Temperature response of decomposition in both fresh litter and SOM was directly related to the chemical composition of the constituent organic matter, explaining 90% and 70% of the variance in Q10 in litter and SOM respectively. The Q10 of litter decreased with increasing proportions of aromatic and O-aromatic compounds, and increased with increased contents of alkyl- and O-alkyl carbons. In contrast, in SOM, decomposition was affected only by carbonyl compounds. To reveal why a certain group of organic chemical compounds affected the temperature sensitivity of organic matter decomposition in litter and SOM, a more detailed characterisation of the (13) C aromatic region using Heteronuclear Single Quantum Coherence (HSQC) was conducted. The results revealed considerable differences in the aromatic region between litter and SOM. This suggests that the correlation between chemical composition of organic matter and the temperature response of decomposition differed between litter and SOM. The temperature response of soil decomposition processes can thus be described by the chemical composition of its constituent organic matter, this paves the way for improved ecosystem modelling of biosphere feedbacks under a changing climate.
• 11. Filippov, Andrey
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Pharmacology. Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience, Clinical Pharmacology.
Interaction of a poly(acrylic acid) oligomer with dimyristoylphosphatidylcholine bilayers2011In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 27, no 7, p. 3754-3761Article in journal (Refereed)
We studied the influence of 5 kDa poly(acrylic acid) (PAA) on the phase state, thermal properties, and lateral diffusion in bilayered systems of dimyristoylphosphatidylcholine (DMPC) using (31)P NMR spectroscopy, differential scanning calorimetry (DSC), (1)H NMR with a pulsed field gradient, and (1)H nuclear Overhauser enhancement spectroscopy (NOESY). The presence of PAA does not change the lamellar structure of the system. (1)H MAS NOESY cross-peaks observed for the interaction between lipid headgroups and polyion protons demonstrated only surface PAA-biomembrane interaction. Small concentrations of PAA (up to ∼4 mol %) lead to the appearance of a new lateral phase with a higher main transition temperature, a lower cooperativity, and a lower enthalpy of transition. Higher concentrations lead to the disappearance of measurable thermal effects. The lateral diffusion coefficient of DMPC and the apparent activation energy of diffusion gradually decreased at PAA concentrations up to around 4 mol %. The observed effects were explained by the formation of at least two types of PAA-DMPC lateral complexes as has been described earlier (Fujiwara, M.; Grubbs, R. H.; Baldeschwieler, J. D. J. Colloid Interface Sci., 1997, 185, 210). The first one is characterized by a stoichiometry of around 28 lipids per polymer, which corresponds to the adsorption of the entire PAA molecule onto the membrane. Lipid molecules of the complex are exchanged with the "pure" lipid bilayer, with the lifetime of the complex being less than 0.1 s. The second type of DMPC-PAA complex is characterized by a stoichiometry of 6 to 7 lipids per polymer and contains PAA molecules that are only partially adsorbed onto the membrane. A decrease in the DMPC diffusion coefficient and activation energy for diffusion in the presence of PAA was explained by the formation of a new cooperative unit for diffusion, which contains the PAA molecule and several molecules of lipids.
• 12. Harrysson Drotz, Stina
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
Contributions of matric and osmotic potentials to the unfrozen water content of frozen soils2009In: Geoderma, ISSN 0016-7061, E-ISSN 1872-6259, Vol. 148, no 3-4, p. 392-8Article in journal (Refereed)
Recent reports show that biogeochemical processes continue when the soil is frozen, but are limited by water availability. However, there is little knowledge about the interactive effects of soil and environmental variables on amounts of unfrozen water in frozen soils. The aims of this study were to determine the contributions of matric and osmotic potentials to the unfrozen water content of frozen soil. We determined the effects of matric and osmotic potential on unfrozen water contents of frozen mineral soil fractions (ranging from coarse sand to fine silt) at − 7 °C, and estimated the contributions of these potentials to liquid water contents in samples from organic surface layers of boreal soils frozen at − 4 °C. In the mineral soil fractions the unfrozen water contents appeared to be governed solely by the osmotic potential, but in the humus layers of the sampled boreal soils both the osmotic and matric potentials control unfrozen water content, with osmotic potential contributing 20 to 69% of the total water potential. We also determined pore size equivalents, where unfrozen water resides at − 4 °C, and found a strong correlation between these equivalents and microbial CO2 production. The larger the pores in which the unfrozen water is found the larger the microbial activity that can be sustained. The osmotic potential may therefore be a key determinant of unfrozen water and carbon dynamics in frozen soil.
• 13.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Arrhenius Laboratory, Stockholm University, Sweden . Umeå University, Faculty of Science and Technology, Department of Chemistry.
Analysis of proton/fluoride spin-lattice NMR dispersion experiment of an ionic liquid, BMIM[PF6] by using molecular dynamics simulations and relaxation theory2015Manuscript (preprint) (Other academic)
Proton/Fluoride spin-lattice nuclear magnetic relaxation dispersion(NMRD) measurements of 1-Butyl-3-methylimidazolium-hexa fluorophosphate (BMIM[PF6])have been carried out using a 1T Stelar FFC2000 fast-field-cycling instrument at proton Larmor frequencies ranging from 10 kHz to 40 MHz and at different temperatures. The NMRD profiles are interpreted by means of a simple relaxation modelbased on the inter- and intra-molecular dipole dipole relaxation mechanims. Using an atomic and a coarse-grained (CG)Molecular Dynamics (MD) simulations at temperature 323 K the relevant dipole-dipole correlation functions are calculated. The result indicate that the NMRD profiles can be rationalized using a combination of intra and inter molecular dipole-dipole couplings. However, both are mainly modulated by molecular reorientation whereas translation diffusion plays a minor role. The molecular reorientation dynamics of BMIM[PF6] ,BMIM+ ion are in the nano secondtime regime whereas the reorientation of [PF6]- is much faster and loses its correlation in the ps regime. The relaxation mechanism for [PF6]- is H-F inter-molecular dipole-dipole coupling which is modulated by the reorientation of the H-containing molecule.
• 14. Lendel, Christofer
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Combined Solution- and Magic Angle Spinning NMR Reveals Regions of Distinct Dynamics in Amyloid β Protofibrils2016In: ChemistrySelect, ISSN 2365-6549, Vol. 1, no 18, p. 5850-5853Article in journal (Refereed)
Solid-state magic angle spinning (MAS) NMR has emerged as an important tool for investigations of protein aggregates and amyloid fibrils, which are not accessible for solution NMR experiments. We recently presented a structural model for amyloid β (Aβ) protofibrils based on MAS-NMR data. The absence of resonances for the N-terminus of Aβ in this dataset suggested that it might be disordered and more dynamic than the structural core. We here provide evidence for a distinct dynamic regime in the N-terminal part of the peptide and show that the structural characteristics of this region can be elucidated using 13C-detected solution NMR. The results shed more light on the structural properties of pre-fibrillar Aβ species and demonstrate the potential of combining MAS and solution NMR experiments for the characterization of structure and dynamics of complex protein assemblies.
• 15.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
The Role of Lipids in Regulation of Programmed Cell Death2016In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 110, no 3, p. 473A-473AArticle in journal (Refereed)
• 16.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics. Umeå University, Faculty of Science and Technology, Department of Chemistry.
The oxidized phospholipid PazePC promotes permeabilization of mitochondrial membranes by Bax2016In: Biochimica et Biophysica Acta - Biomembranes, ISSN 0005-2736, E-ISSN 1879-2642, Vol. 1858, no 6, p. 1288-1297Article in journal (Refereed)
Mitochondria play a crucial role in programmed cell death via the intrinsic apoptotic pathway, which is tightly regulated by the B-cell CLL/lymphoma-2 (Bcl-2) protein family. Intracellular oxidative stress causes the translocation of Bax, a pro-apoptotic family member, to the mitochondrial outer membrane (MOM) where it induces membrane permeabilization. Oxidized phospholipids (OxPls) generated in the MOM during oxidative stress directly affect the onset and progression of mitochondria-mediated apoptosis. Here we use MOM-mimicking lipid vesicles doped with varying concentrations of 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC), an OxPl species known to significantly enhance Bax-membrane association, to investigate three key aspects of Bax's action at the MOM: 1) induction of Bax pores in membranes without additional mediator proteins, 2) existence of a threshold OxPl concentration required for Bax-membrane action and 3) mechanism by which PazePC disturbs membrane organization to facilitate Bax penetration. Fluorescence leakage studies revealed that Bax-induced leakage, especially its rate, increased with the vesicles' PazePC content without any detectable threshold neither for OxPl nor Bax. Moreover, the leakage rate correlated with the Bax to lipid ratio and the PazePC content. Solid state NMR studies and calorimetric experiments on the lipid vesicles confirmed that OxPl incorporation disrupted the membrane's organization, enabling Bax to penetrate into the membrane. In addition, 15N cross polarization (CP) and insensitive nuclei enhanced by polarization transfer (INEPT) MAS NMR experiments using uniformly 15N-labeled Bax revealed dynamically restricted helical segments of Bax embedded in the membrane, while highly flexible protein segments were located outside or at the membrane surface.
• 17.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
A combined molecular dynamic simulation and Urea 14N NMR relaxation study of the Urea - lysozyme system2010In: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, ISSN 1386-1425, E-ISSN 1873-3557, Vol. 75, no 3, p. 953-9Article in journal (Refereed)
Urea in the lysozyme solvation shell has been studied by utilizing a combination of urea , water NMR relaxation experiments and a molecular dynamics simulation of the urea–lysozyme system. Samples with lysozyme in the native fold in water as well as in 3 M urea have been studied, as well as denatured lysozyme in a 8.5 M urea solvent. The spin relaxation rates of the samples with folded protein show a clear field dependence, which is consistent with a few urea molecules having long residence times on the protein surface and preferentially located in pockets and grooves on the protein. By combining the 3 M urea NMR relaxation data and data from the MD simulation, a full parameter set of the relaxation model is found which can successfully predict the experimental relaxation rates of the 3 M urea sample. However, in the parameter fitting it is evident that the rotational dynamics of urea in the MD simulation is slightly too fast to be consistent with the NMR relaxation rates, perhaps a result of the fast dynamics of the TIP3P water model. The relaxation rates of urea in the proximity of the unfolded lysozyme lack field dependence, which can be interpreted as a loss of pockets and grooves on the denatured protein. The extracted model parameters from the 3 M sample are adjusted and tested on a simple model of the unfolded protein sample and are seen to be in agreement with the relaxation rates. It is shown that the combination of NMR relaxation and MD simulations can be used to create a microscopic picture of the solvent at the protein interface, which can be used for example in the study of chemical denaturation.
• 18.
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry. Umeå University, Faculty of Science and Technology, Chemistry. Umeå University, Faculty of Science and Technology, Chemistry.
Association of amyloid-β peptide with membrane surfaces monitored by solid state NMR2002In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 4, no 22, p. 5524-5530Article in journal (Refereed)
Amyloid-β peptide (Aβ), a key substance in Alzheimers disease (AD), is characterized by its abnormal folding into neurotoxic aggregates. Since Aβ comprises an extracellular and transmembrane domain, some of its neurotoxic actions might be exerted via interactions with neuronal membranes. Wideline and magic angle spinning 14N and 31P NMR have been used in combination with differential scanning calorimetry and circular dichroism spectroscopy to investigate the association between Aβ1–40 peptide and membranes with different electrostatic surface potentials. Calorimetric measurements showed that all membrane systems were in the liquid crystalline state at 308 K. Binding of Aβ1–40 at a 30 1 lipid/peptide ratio to membranes composed of neutral dimyristoyl-phosphatidylcholine (DMPC) and negatively charged dimyristoylphosphatidylglycerol (DMPG) at a 4 : 1 molar ratio is mainly driven electrostatically, reflected in characteristic changes of the isotropic 31P chemical shift values for both lipids. In addition, the average orientation of the choline headgroup of DMPC, with its electric P–N+(CH3)3 dipole, changed directly in response to the reduced negative membrane surface potential. The deviation in tilt angle of the PN vector relative to the membrane surface is manifested in the observed 14N NMR quadrupole splitting and can therefore be described semiquantitatively. Adding Aβ1–40 to membranes with nominal neutral surface charge, but composed of a ternary mixture of DMPC with DMPG and the cationic amphiphile didodecyldimethyl–ammonium bromide (DDAB) at a 3 : 1 : 1 molar ratio revealed surprisingly electrostatic interactions visible in the NMR spectra. Since Aβ1–40 does not bind to neutral DMPC bilayers a model is proposed, in which on a molecular level the charged residues of Aβ1–40 peptide can interact independently with lipid headgroups of various charges in these microscopically heterogeneous systems.
• 19. Maljanen, M
Umeå University, Faculty of Science and Technology, Chemistry.
Nitrous oxide production in boreal soils with variable organic matter content at low temperature – snow manipulation experiment2009In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 6, no 11, p. 2461-73Article in journal (Refereed)
Agricultural soils are the most important sources for the greenhouse gas nitrous oxide (N2O), which is produced and emitted from soils also at low temperatures. The processes behind emissions at low temperatures are still poorly known. Snow is a good insulator and it keeps soil temperature rather constant. To simulate the effects of a reduction in snow depth on N2O emission in warming climate, snow pack was removed from experimental plots on three different agricultural soils (sand, mull, peat). Removal of snow lowered soil temperature and increased the extent and duration of soil frost in sand and mull soils. This led to enhanced N2O emissions during freezing and thawing events. The cumulative emissions during the first year when snow was removed over the whole winter were 0.25, 0.66 and 3.0 g N2O-N m−2 yr−1 in control plots of sand, mull and peat soils, respectively. In the treatment plots, without snow cover, the respective cumulative emissions were 0.37, 1.3 and 3.3 g N2O-N m−2 yr−1. Shorter snow manipulation during the second year did not increase the annual emissions. Only 20% of the N2O emission occurred during the growing season. Thus, these results highlight the importance of the winter season for this exchange and that the year-round measurements of annual N2O emissions from boreal soils are integral for estimating their N2O source strength. N2O accumulated in the frozen soil during winter and the soil N2O concentration correlated with the depth of frost but not with the winter N2O emission rates per se. Also laboratory incubations of soil samples showed high production rates of N2O at temperatures below 0°C, especially in the sand and peat soils.
• 20.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Preparation and characterization of sizable macroporous epoxy resin-based monolithic supports for flow-through systems2009In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 32, no 15-16, p. 2608-2618Article in journal (Refereed)
This paper presents further results from our efforts to prepare sizable macroporous monolithic materials from epoxy resins and polyamines by emulsion polymerization. For their uses as supports in flow systems, the study aimed at developing materials possessing maximum fluid permeability, high mechanical stability, and a controlled porosity and surface area. Characterization of the materials has been carried out using different techniques, focusing on morphological and mechanical features, and on the surface chemistry. Morphology and porosity were studied with SEM, nitrogen adsorption/desorption, mercury intrusion porosimetry (MIP), and (2)H NMR cryoporosimetry. The chemical composition of the bulk structures and their surfaces was studied by means of bulk elemental analysis and X-ray photoelectron spectroscopy, and potentiometric titration was used to assess the relative amounts of amines and epoxy groups. Essentially, the morphological features were a high fluid permeability, but rather low specific surface area. Convective flow was facilitated by large, interconnected, and evenly spaced macropores which were formed by nonporous skeletons of the connected-rod type. Despite the interfacial nature of the polymerization, the bulk and the surface of the fully cured materials showed similar elemental compositions. All materials were found to have a high surface density of hydroxyl groups, which facilitates functionalization reactions.
• 21. Pawar, Prashant Mohan-Anupama
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
In muro deacetylation of xylan affects lignin properties and improves saccharification of aspen wood2017In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 10, article id 98Article in journal (Refereed)
Background: Lignocellulose from fast growing hardwood species is a preferred source of polysaccharides for advanced biofuels and “green” chemicals. However, the extensive acetylation of hardwood xylan hinders lignocellulose saccharification by obstructing enzymatic xylan hydrolysis and causing inhibitory acetic acid concentrations during microbial sugar fermentation. To optimize lignocellulose for cost-effective saccharification and biofuel production, an acetyl xylan esterase AnAXE1 from Aspergillus niger was introduced into aspen and targeted to cell walls.
Results: AnAXE1-expressing plants exhibited reduced xylan acetylation and grew normally. Without pretreatment, their lignocellulose yielded over 25% more glucose per unit mass of wood (dry weight) than wild-type plants. Glucose yields were less improved (+7%) after acid pretreatment, which hydrolyses xylan. The results indicate that AnAXE1 expression also reduced the molecular weight of xylan, and xylan–lignin complexes and/or lignin co-extracted with xylan, increased cellulose crystallinity, altered the lignin composition, reducing its syringyl to guaiacyl ratio, and increased lignin solubility in dioxane and hot water. Lignin-associated carbohydrates became enriched in xylose residues, indicating a higher content of xylo-oligosaccharides.
Conclusions: This work revealed several changes in plant cell walls caused by deacetylation of xylan. We propose that deacetylated xylan is partially hydrolyzed in the cell walls, liberating xylo-oligosaccharides and their associated lignin oligomers from the cell wall network. Deacetylating xylan thus not only increases its susceptibility to hydrolytic enzymes during saccharification but also changes the cell wall architecture, increasing the extractability of lignin and xylan and facilitating saccharification.
• 22. Pawar, Prashant Mohan-Anupama
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Downregulation of RWA genes in hybrid aspen affects xylan acetylation and wood saccharification2017In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 214, p. 1491-1505Article in journal (Refereed)
High acetylation of angiosperm wood hinders its conversion to sugars by glycoside hydrolases, subsequent ethanol fermentation and (hence) its use for biofuel production. We studied the REDUCED WALL ACETYLATION (RWA) gene family of the hardwood model Populus to evaluate its potential for improving saccharification. The family has two clades, AB and CD, containing two genes each. All four genes are expressed in developing wood but only RWA-A and -B are activated by master switches of the secondary cell wall PtNST1 and PtMYB21. Histochemical analysis of promoter:: GUS lines in hybrid aspen (Populus tremula x tremuloides) showed activation of RWA-A and -B promoters in the secondary wall formation zone, while RWA-C and -D promoter activity was diffuse. Ectopic downregulation of either clade reduced wood xylan and xyloglucan acetylation. Suppressing both clades simultaneously using the wood-specific promoter reduced wood acetylation by 25% and decreased acetylation at position 2 of Xylp in the dimethyl sulfoxide-extracted xylan. This did not affect plant growth but decreased xylose and increased glucose contents in the noncellulosic monosaccharide fraction, and increased glucose and xylose yields of wood enzymatic hydrolysis without pretreatment. Both RWA clades regulate wood xylan acetylation in aspen and are promising targets to improve wood saccharification.
• 23.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Laboratory of Industrial Chemistry and Reaction Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Real-time 31P NMR investigation on the catalytic behavior of the enzyme Adenylate kinase in the matrix of a switchable ionic liquid2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 2, p. 3764-3768Article in journal (Refereed)
The integration of highly efficient enzymatic catalysis with the solvation properties of ionic liquids for an environmentally friendly and efficient use of raw materials such as wood requires fundamental knowledge about the influence of relevant ionic liquids on enzymes. Switchable ionic liquids (SIL) are promising candidates for implementation of enzymatic treatments of raw materials. One industrially interesting SIL is constituted by monoethanol amine (MEA) and 1,8-diazabicyclo-[5.4.0]-undec-7-ene (DBU) formed with sulfur dioxide (SO2) as the coupling media (DBU-SO2-MEASIL). It has the ability to solubilize the matrix of lignocellulosic biomass while leaving the cellulose backbone intact. Using a novel 31P NMR-based real-time assay we show that this SIL is compatible with enzymatic catalysis because a model enzyme, adenylate kinase, retains its activity in up to at least 25 wt % of DBU-SO2-MEASIL. Thus this SIL appears suitable for, for example, enzymatic degradation of hemicellulose.
• 24. Rowat, Amy C.
Umeå University, Faculty of Medicine, Medical Biochemistry and Biophsyics. Umeå University, Faculty of Science and Technology, Chemistry. Umeå University, Faculty of Science and Technology, Chemistry.
Commentary: Farnesylated peptides in model membranes: a biophysical investigation (vol 33, pg 300, 2003)2004In: European Biophysics Journal, Vol. 33, no 6, p. 562-3Article in journal (Refereed)
• 25. Rowat, Amy C.
Umeå University, Faculty of Medicine, Medical Biochemistry and Biophsyics. Faculty of Science and Technology, Chemistry.
Farnesylated peptides in model membranes: a biophysical investigation2004In: European Biophysics Journal, ISSN 0175-7571 (Print) 1432-1017 (Online), Vol. 33, no 4, p. 300-9Article in journal (Refereed)
Protein prenylation plays an important role in signal transduction, protein–protein interactions, and the localization and association of proteins with membranes. Using three different techniques, this study physically characterizes the interactions between model dimyristoylphosphatidylcholine membranes and a series of farnesylated peptides. Magic angle spinning nuclear Overhauser enhancement spectroscopy and differential scanning calorimetry reveal that both charged [Ac-Asn-Lys-Asn-Cys-(farnesyl)-OMe and Ac-Asn-Lys-Asn-Cys-(farnesyl)-NH2] and uncharged [Ac-Cys-(farnesyl)-OMe and farnesol] species partition into dimyristoylphosphatidylcholine bilayers. Calorimetry and vesicle fluctuation analysis of giant unilamellar vesicles show that the charged peptides modestly decrease the main gel–fluid phase transition and markedly increase the bending rigidity of large unilamellar vesicles. Uncharged species, on the other hand, dramatically decrease the main phase transition and modestly decrease the bending rigidity. No difference with carboxyl methylation is detected.
• 26.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Noncooperative folding of subdomains in Adenylate Kinase2009In: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 48, no 9, p. 1911-1927Article in journal (Refereed)
Conformational change is regulating the biological activity of a large number of proteins and enzymes. Efforts in structural biology have provided molecular descriptions of the interactions that stabilize the stable ground states on the reaction trajectories during conformational change. Less is known about equilibrium thermodynamic stabilities of the polypeptide segments that participate in structural changes and whether the stabilities are relevant for the reaction pathway. Adenylate kinase (Adk) is composed of three subdomains: CORE, ATPlid, and AMPbd. ATPlid and AMPbd are flexible nucleotide binding subdomains where large-scale conformational changes are directly coupled to catalytic activity. In this report, the equilibrium thermodynamic stabilities of Adk from both mesophilic and hyperthermophilic bacteria were investigated using solution state NMR spectroscopy together with protein engineering experiments. Equilibrium hydrogen to deuterium exchange experiments indicate that the flexible subdomains are of significantly lower thermodynamic stability compared to the CORE subdomain. Using site-directed mutagenesis, parts of ATPlid and AMPbd could be selectively unfolded as a result of perturbation of hydrophobic clusters located in these respective subdomains. Analysis of the perturbed Adk variants using NMR spin relaxation and Cα chemical shifts shows that the CORE subdomain can fold independently of ATPlid and AMPbd; consequently, folding of the two flexible subdomains occurs independently of each other. Based on the experimental results it is apparent that the flexible subdomains fold into their native structure in a noncooperative manner with respect to the CORE subdomain. These results are discussed in light of the catalytically relevant conformational change of ATPlid and AMPbd.
• 27. Segura, Javier H.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Industrial Chemistry & Reaction Engineering, Process Chemistry Centre, Åbo. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
Microbial mineralization of cellulose in frozen soils2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, no 1, article id 1154Article in journal (Refereed)
High-latitude soils store ~40% of the global soil carbon and experience winters of up to 6 months or more. The winter soil CO2 efflux importantly contributes to the annual CO2 budget. Microorganisms can metabolize short chain carbon compounds in frozen soils. However, soil organic matter (SOM) is dominated by biopolymers, requiring exoenzymatic hydrolysis prior to mineralization. For winter SOM decomposition to have a substantial influence on soil carbon balances it is crucial whether or not biopolymers can be metabolized in frozen soils. We added 13C-labeled cellulose to frozen (−4 °C) mesocosms of boreal forest soil and followed its decomposition. Here we show that cellulose biopolymers are hydrolyzed under frozen conditions sustaining both CO2 production and microbial growth contributing to slow, but persistent, SOM mineralization. Given the long periods with frozen soils at high latitudes these findings are essential for understanding the contribution from winter to the global carbon balance.
• 28.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, UK.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Bifluoride ([HF2](-)) formation at the fluoridated aluminium hydroxide/water interface2016In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, no 22, p. 9045-9050Article in journal (Refereed)
This study uncovers bifluoride-type (difluorohydrogenate(I); [HF2](-)) species formed at mineral/water interfaces. Bifluoride forms at equivalent to Al-F surface sites resulting from the partial fluoridation of gibbsite (gamma-Al(OH3)) and bayerite (alpha-Al(OH3)) particles exposed to aqueous solutions of 50 mM NaF. Fluoride removal from these solutions is proton-promoted and results in a strongly self-buffered suspensions at circumneutral pH, proceeds at a F : H consumption ratio of 2 : 1, and with recorded losses of up to 17 mM fluoride (58 F nm(-2)). These loadings exceed crystallographic site densities by a factor of 3-4, yet the reactions have no resolvable impact on particle size, shape and mineralogy. X-ray photoelectron spectroscopy (XPS) of frozen (-155 degrees C) wet mineral pastes revealed coexisting surface F- and HF0 species. Electron energy loss features pointed to multilayer distribution of these species at the mineral/water interface. XPS also uncovered a distinct form of Na+ involved in binding fluoride-bearing species. XPS and solid state magic angle spinning F-19 nuclear magnetic resonance measurements showed that these fluoride species were highly comparable to a sodium-bifluoride (NaHF2) reference. First layer surface species are represented as =Al-F-H-F-Al= and =Al-F-Na-F-Al=, and may form multi-layered species into the mineral/water interface. These results consequently point to a potentially overlooked inorganic fluorine species in a technologically relevant mineral/water interfacial systems.
• 29. Song, Yu
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
Thermodynamics of Hg(II) bonding to thiol groups in Suwannee River natural organic matter resolved by competitive ligand exchange, Hg L-III-Edge EXAFS and H-1 NMR spectroscopy2018In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 15, p. 8292-8301Article in journal (Refereed)
A molecular level understanding of the thermodynamics and kinetics of the chemical bonding between mercury, Hg(II), and natural organic matter (NOM) associated thiol functional groups (NOM-RSH) is required if bioavailability and transformation processes of Hg in the environment are to be fully understood. This study provides the thermodynamic stability of the Hg(NOM-RS)(2) structure using a robust method in which cysteine (Cys) served as a competing ligand to NOM (Suwannee River 2R101N sample) associated RSH groups. The concentration of the latter was quantified to be 7.5 +/- 0.4 mu mol g(-1) NOM by Hg L-III-edge EXAFS spectroscopy. The Hg(Cys)(2) molecule concentration in chemical equilibrium with the Hg(II)-NOM complexes was directly determined by HPLC-ICPMS and losses of free Cys due to secondary reactions with NOM was accounted for in experiments using H-1 NMR spectroscopy and C-13 isotope labeled Cys. The log K +/- SD for the formation of the Hg(NOM-RS)(2) molecular structure, Hg2+ + 2NOM-RS- = Hg(NOM-RS)(2), and for the Hg(Cys)(NOM-RS) mixed complex, Hg2+ + Cys(-) + NOM-RS- = Hg(Cys)(NOM-RS), were determined to be 40.0 +/- 0.2 and 38.5 +/- 0.2, respectively, at pH 3.0. The magnitude of these constants was further confirmed by H-1 NMR spectroscopy and the Hg(NOM-RS)(2) structure was verified by Hg L-III-edge EXAFS spectroscopy. An important finding is that the thermodynamic stabilities of the complexes Hg(NOM-RS)(2), Hg(Cys)(NOM-RS) and Hg(Cys)(2) are very similar in magnitude at pH values <7, when all thiol groups are protonated. Together with data on 15 low molecular mass (LMM) thiols, as determined by the same method (Liem-Ngyuen et al. Thermodynamic stability of mercury(II) complexes formed with environmentally relevant low-molecular-mass thiols studied by competing ligand exchange and density functional theory. Environ. Chem. 2017, 14, (4), 243-253.), the constants for Hg(NOM-RS)(2) and Hg(Cys)(NOM-RS) represent an internally consistent thermodynamic data set that we recommend is used in studies where the chemical speciation of Hg(II) is determined in the presence of NOM and LMM thiols.
• 30.
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry.
An NMR line shape and relaxation analysis of heavy water powder spectra of the L, L and P phases in the DPPC/water system2003In: Physical Chemistry Chemical Physics, Vol. 5, p. 2114-21Article in journal (Refereed)
The 2H2O NMR powder line shapes and relaxation times, T1 and T2, of the liquid crystal L, the intermediate P and the gel L phases of dipalmitoylphosphatidylcholine (DPPC)/2H2O-system are analysed. The water structure and dynamics of the lipid/water interfaces of DPPC in the hydration regime, where all water molecules are associated to the interface, are described in terms of orientational order parameters and correlation times. The line shape of the ripple phase (P) is analysed assuming model parameters of the gel or liquid crystalline phase. The narrow line shape of the ripple phase is partly due to an extra average of the quadrupole interaction because of lateral diffusion along the curved surface, reducing the splitting with a factor 0.5–0.2 depending on the nature of the curved ripple surface. However, more importantly, an extra reduction of the quadrupole splitting may be due to the same reorganization of water, among bound sites with different signs of the order parameter, which also explains the increase in the quadrupole splitting with temperature observed in the liquid crystalline phase. The linewidths in 14N MAS NMR spectra clearly indicate slow dynamics of the polar headgroup in the ripple phase. The results indicate that the headgroup hydrations of the ripple and liquid crystalline phases are similar, while the acyl chains are still in their gel state in the ripple phase. The increased headgroup area introduces a stress, as confirmed by the slow headgroup dynamics, which causes the bilayer to curve in the ripple phase.
• 31.
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry.
H-2 NMR relaxation and line shape analysis of water in a lamellar liquid crystalline phase formed by dodecyldimethylamineoxide (DDAO) and (H2O)-H-22001In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1520-6106, Vol. 105, no 50, p. 12524-8Article in journal (Refereed)
Present study combines NMR relaxation and line shape analysis for heavy water in the lamellar liquid crystalline phase of DDAO/(2)-H2O, NMR spin-lattice, spin-spin relaxation times and the quadrupole splitting are measured at two temperatures and three different water contents in the hydration regime. A molecular picture of water hydration of the DDAO/(2)-H2O interface is extracted, which indicates a much more rapid water translational diffusion along the detergent interface, as compared to phospholipid interfaces. The local order and dynamics of the bound water are, however, not changing much between the two interfaces. This indicates, that local interactions of water with the headgroup are not much dependent on the actual phase or detergent system. This work also presents clear experimental evidence for a dip at the magic angle of the H-2 powder spectrum, as theoretically predicted. Raising the temperature removes this observed dip at the isotropic frequency. This corresponds to an increase in the correlation time tau (c) from 8.5 ns at 25 degreesC to 20 ns at 55 degreesC, where tau (c) is related to translational dynamics of water along the detergent/water interface. However, this counter-intuitive increase in tau (c) with temperature may be interpreted as a reorganization of water at the interface, as is further supported by increasing quadrupolar splittings with increasing temperature.
• 32. Sparrman, Tobias
Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
Quantifying unfrozen water in frozen soil by high-field 2H NMR2004In: Environmental Science & Technology, Vol. 38, no 20, p. 5420-5Article in journal (Refereed)
• 33.
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry. Umeå University, Faculty of Science and Technology, Chemistry.
Phase diagrams of systems with cationic α-helical membrane-spanning model peptides and dioleoylphosphatidylcholine2001In: Advances in Colloid and Interface Science, Vol. 89-90, no 239-61Article in journal (Refereed)
Ternary phase diagrams have been constructed of systems with dioleoylphosphatidylcholine (DOPC) and water, and two α-helical membrane-spanning model peptides, KKLAKK16[KK(LA)6KK] and KKLAKK20[KK(LA)8KK]. It was found that these peptides induced non-lamellar liquid crystalline phases. The amount of peptide needed for this phase transition depended on the water content and the temperature; and for KKLAKK16, a smaller amount of peptide was needed to induce non-lamellar phases than for KKLAKK20. Both peptides were found to induce an isotropic phase, and KKLAKK16 also induced a reversed hexagonal phase. Both peptides may also reside in a lamellar (Lα) phase. When magic angle spinning (MAS) 31P NMR experiments were performed on samples containing the Lα phase and an isotropic phase, four different isotropic chemical shifts were observed. The isotropic chemical shifts could be assigned to the phases, using spinning sidebands to calculate the chemical shift anisotropy (CSA) corresponding to each isotropic shift. MAS 13C NMR also indicated a difference in the aggregational state of the peptides between the Lα and isotropic phases. The phase diagrams were compared to the phase diagram of a similar model peptide, AWW(LA)5WWA in systems with DOPC and water. It was concluded that the phase behaviour was influenced by both electrostatic interactions between the peptides and the lipid headgroups, and the difference between the hydrophobic length of the peptide and the hydrophobic thickness of the lipid bilayer.
• 34. Tilston, E L
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Unfrozen water content moderates temperature dependence of sub-zero microbial respiration2010In: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 42, no 9, p. 1396-1407Article in journal (Refereed)
Abrupt increases in the temperature sensitivity of soil respiration below 0 °C have been interpreted as a change in the dominance of other co-dependent environmental controls, such as the availability of liquid-state water. Yet the relationship between unfrozen water content and soil respiration at sub-zero temperatures has received little attention because of difficulties in measuring unfrozen water contents. Using a recently-developed semi-solid 2H NMR technique the unfrozen water content present in seasonally frozen boreal forest soils was quantified and related to biotic CO2 efflux in laboratory microcosms maintained at temperatures between −0.5 and −8 °C. In both soils the unfrozen water content had an exponential relationship with temperature and was increased by addition of KCl solutions of defined osmotic potential. Approximately 13% unfrozen water was required to release the dependence of soil respiration on unfrozen water content. Depending on the osmotic potential of soil solution, this threshold unfrozen water content was associated with temperatures down to −6 °C; yet if temperature were the predictor of CO2 efflux, then the abrupt increase in the temperature sensitivity of CO2 efflux was associated with −2 °C, except in soils amended with −1500 kPa KCl which did not show any abrupt changes in temperature sensitivity. The KCl-amendments also had the effect of decreasing Q10 values and activation energies (Ea) by factors of 100 and three, respectively, to values comparable with those for soil respiration in unfrozen soil. The disparity between the threshold temperatures and the reductions in Q10 values and activation energies after KCl amendment indicates the significance of unfrozen water availability as an environmental control of equal importance to temperature acting on sub-zero soil respiration. However, this significance was diminished when soils were supplied with abundant labile C (sucrose) and the influences of other environmental controls, allied to the solubility and diffusion of respiratory substrates and gases, are considered to increase.
• 35.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Department of Chemistry.
A 2H nuclear magnetic resonance study of the state of water in neat silica and zwitterionic stationary phases and its influence on the chromatographic retention characteristics in hydrophilic interaction high-performance liquid chromatography2011In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1218, no 38, p. 6630-6638Article in journal (Refereed)
(2)H NMR has been used as a tool for probing the state of water in hydrophilic stationary phases for liquid chromatography at temperatures between -80 and +4°C. The fraction of water that remained unfrozen in four different neat silicas with nominal pore sizes between 60 and 300Å, and in silicas with polymeric sulfobetaine zwitterionic functionalities prepared in different ways, could be determined by measurements of the line widths and temperature-corrected integrals of the (2)H signals. The phase transitions detected during thawing made it possible to estimate the amount of non-freezable water in each phase. A distinct difference was seen between the neat and modified silicas tested. For the neat silicas, the relationship between the freezing point depression and their pore size followed the expected Gibbs-Thomson relationship. The polymeric stationary phases were found to contain considerably higher amounts of non-freezable water compared to the neat silica, which is attributed to the structural effect that the sulfobetaine polymers have on the water layer close to the stationary phase surface. The sulfobetaine stationary phases were used alongside the 100Å silica to separate a number of polar compounds in hydrophilic interaction (HILIC) mode, and the retention characteristics could be explained in terms of the surface water structure, as well as by the porous properties of the stationary phases. This provides solid evidence supporting a partitioning mechanism, or at least of the existence of an immobilized layer of water into which partitioning could be occurring.
• 36. Öquist, Mats G.
Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences. Department of Forest Ecology & Management, Swedish University of Agricultural Sciences (SLU), Umeå, Sweden. Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
The effect of temperature and substrate quality on the carbon use efficiency of saprotrophic decomposition2017In: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 414, no 1, p. 113-125Article in journal (Refereed)
Background and aims: Mineralization of soil organic matter (SOM) constitutes a major carbon flux to the atmosphere. The carbon use efficiency (CUE) of the saprotrophic microorganisms mineralizing SOM is integral for soil carbon dynamics. Here we investigate how the CUE is affected by temperature, metabolic conditions, and the molecular complexity of the substrate.
Methods: We incubated O-horizon soil samples (with either 13C–glucose or 13C–cellulose) from a boreal coniferous forest at 4, 9, 14, and 19 °C, and calculated CUEs based on the amount of 13C–CO2and 13C–labelled microbial biomass produced. The effects of substrate, temperature, and metabolic conditions (representing unlimited substrate supply and substrate limitation) on CUE were evaluated.
Results: CUE from metabolizing glucose was higher as compared to cellulose. A slight decrease in CUE with increasing temperature was observed in glucose amended samples (but only in the range 9–19 °C), but not in cellulose amended samples. CUE differed significantly with metabolic conditions, i.e. CUE was higher during unlimited growth conditions as compared to conditions with substrate limitation.
Conclusions: We conclude that it is integral to account for both differences in CUE during different metabolic phases, as well as complexity of substrate, when interpreting temperature dependence on CUE in incubation studies.
• 37. Öquist, Mats
Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
Water availability controls microbial temperature responses in frozen soil CO2 production2009In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 15, no 11, p. 2715-22Article in journal (Refereed)
Soil processes in high-latitude regions during winter are important contributors to global carbon circulation, but our understanding of the mechanisms controlling these processes is poor and observed temperature response coefficients of CO2 production in frozen soils deviate markedly from thermodynamically predicted responses (sometimes by several orders of magnitude). We investigated the temperature response of CO2 production in 23 unfrozen and frozen surface soil samples from various types of boreal forests and peatland ecosystems and also measured changes in water content in them after freezing. We demonstrate that deviations in temperature responses at subzero temperatures primarily emanates from water deficiency caused by freezing of the soil water, and that the amount of unfrozen water is mainly determined by the quality of the soil organic matter, which is linked to the vegetation cover. Factoring out the contribution of water limitation to the CO2 temperature responses yields response coefficients that agree well with expectations based on thermodynamic theory concerning biochemical temperature responses. This partitioning between a pure temperature response and the effect of water availability on the response of soil CO2 production at low temperatures is crucial for a thorough understanding of low-temperature soil processes and for accurate predictions of C-balances in northern terrestrial ecosystems.
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https://www.gradesaver.com/textbooks/math/calculus/calculus-early-transcendentals-8th-edition/chapter-1-section-1-5-inverse-functions-and-logarithms-1-5-exercises-page-68/64
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## Calculus: Early Transcendentals 8th Edition
a) $\tan^{-1}\sqrt3=\frac{\pi}{3}$ b) $\arctan(-1)=-\frac{\pi}{4}$
a) let $\tan^{-1}\sqrt3=\theta , -\frac{\pi}{2}\lt\theta\lt\frac{\pi}{2}$ $\tan\theta=\sqrt3$ $\theta=\frac{\pi}{3}+k\pi$ $\because -\frac{\pi}{2}\lt\theta\lt\frac{\pi}{2}$, let $k=0, \theta=\frac{\pi}{3}$ $\therefore \tan^{-1}\sqrt3=\frac{\pi}{3}$ b) let $\arctan(-1) =\theta, -\frac{\pi}{2}\lt\theta\lt\frac{\pi}{2}$ $\tan\theta=-1$ $\theta=-\frac{\pi}{4}+k\pi$ $\because -\frac{\pi}{2}\lt\theta\lt\frac{\pi}{2}$, let $k=0, \theta=-\frac{\pi}{4}$ $\therefore \arctan(-1)=-\frac{\pi}{4}$
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https://brahma.tcs.tifr.res.in/print/3308
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# Size-sensitive Packing Number for the Hamming Cube and its Consequences
Kunal Dutta
## Affiliation:
Max-Planck-Institut fur Informatik
Department 1: Algorithms and Complexity
Campus E1 4, Room 319
66123 Saarbrucken
Germany
## Time:
Friday, 5 December 2014, 14:00 to 15:30
• AG-69
## Organisers:
Abstract: An abstract set system, or hypergraph, consists of a universe (here assumed finite), together with a subset of its power set. A set-system is $\delta$-separated if any pair of its constituent subsets have symmetric difference at least $\delta$. In 1992, Haussler proved an optimal upper bound on the packing number for $\delta$-separated set systems having bounded primal shatter dimension. A set system with bounded primal shatter dimension is said to have \emph{size-sensitive shattering constants} $d_1$ and $d_2$, if the number of distinct projections of the system on any subset of its universe having $m$ elements, is at most $O(m^{d_1}k^{d_2})$.
We prove a size-sensitive version of Haussler’s Packing lemma [Hau92] for set-systems with bounded primal shatter dimension, which have an additional size-sensitive property. This answers a question asked by Ezra [Ezr14]. As a consequence of this result we get an improvement on the discrepancy bounds for set systems with the above size sensitive property. Improved bound on the discrepancy for these special set systems also implies an improvement in the size of $(\nu, \alpha)$-samples (and relative $(\varepsilon,\delta)$-approximations) (joint work with Arijit Ghosh, Max-Planck-Institute, Saarbrücken).
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https://www.sparrho.com/item/complex-network-analysis-of-resting-state-eeg-in-amnestic-mild-cognitive-impairment-patients-with-type-2-diabetes/73fbf2/
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Complex network analysis of resting state EEG in amnestic mild cognitive impairment patients with type 2 diabetes.
Research paper by Ke K Zeng, Yinghua Y Wang, Gaoxiang G Ouyang, Zhijie Z Bian, Lei L Wang, Xiaoli X Li
Indexed on: 19 Nov '15Published on: 19 Nov '15Published in: Frontiers in computational neuroscience
Abstract
Diabetes is a great risk factor for dementia and mild cognitive impairment (MCI). This study investigates whether complex network-derived features in resting state EEG (rsEEG) could be applied as a biomarker to distinguish amnestic mild cognitive impairment (aMCI) from normal cognitive function in subjects with type 2 diabetes (T2D).In this study, EEG was recorded in 28 patients with T2D (16 aMCI patients and 12 controls) during a no-task eyes-closed resting state. Pair-wise synchronization of rsEEG signals were assessed in six frequency bands (delta, theta, lower alpha, upper alpha, beta, and gamma) using phase lag index (PLI) and grouped into long distance (intra- and inter-hemispheric) and short distance interactions. PLI-weighted connectivity networks were also constructed, and characterized by mean clustering coefficient and path length. The correlation of these features and Montreal Cognitive Assessment (MoCA) scores was assessed.Main findings of this study were as follows: (1) In comparison with controls, patients with aMCI had a significant decrease of global mean PLI in lower alpha, upper alpha, and beta bands. Lower functional connection at short and long intra-hemispheric distance mainly appeared on the left hemisphere. (2) In the lower alpha band, clustering coefficient was significantly lower in aMCI group, and the path length significantly increased. (3) Cognitive status measured by MoCA had a significant positive correlation with cluster coefficient and negative correlation with path length in lower alpha band.The brain network of aMCI patients displayed a disconnection syndrome and a loss of small-world architecture. The correlation between cognitive states and network characteristics suggested that the more in deterioration of the diabetes patients' cognitive state, the less optimal the network organization become. Hence, the complex network-derived biomarkers based on EEG could be employed to track cognitive function of diabetic patients and provide a new diagnosis tool for aMCI.
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http://math.stackexchange.com/questions/43473/if-n-neq-m-then-mathbbrn-is-not-homeomorphic-to-mathbbrm/43476
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# If $n\neq m$ then $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$
I want to prove that if $n\neq m$ then $\mathbb{R}^n$ is not homeomorphic to $\mathbb{R}^m$.
This deceptively simple topology question came up on an algebraic topology worksheet on which the rest of the questions centre around the Mayer-Vietoris sequence and degrees of maps. I have to admit I have little idea about how to proceed, except maybe to use homotopy types (and I'm not even sure how to start there). A hint or two would be very handy...
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@user8268: Yes I believe I can. $\mathbb{R}^n\setminus\{0\} \simeq S^{n-1}$, $\mathbb{R}^m\setminus\{0\} \simeq S^{m-1}$. But if $S^{n-1}$ and $S^{m-1}$ were homotopy equivalent, then $H_*(S^{n-1}) = H_*(S^{m-1})$, which is false. So this gives that $\mathbb{R}^n \setminus\{0\}$ and $\mathbb{R}^m\setminus \{0\}$ are not even homotopy equivalent. Ah, I think I see how to proceed with the last bit now, thanks to Aaron's answer below. Cheers! :) – Sputnik Jun 5 '11 at 20:33
mathoverflow.net/questions/34232/… – user9413 Jun 6 '11 at 3:13
Hint: If $\varphi: \mathbb{R}^m\to \mathbb{R}^n$ is a homeomorphism, then $\mathbb{R}^m\setminus x$ is homeomorphic to $\mathbb{R}^n\setminus \varphi(x)$. Compute the homology.
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haha, my kind of thinking ;) – gfes Jun 5 '11 at 20:29
@gfes Indeed! Actually, when I hit submit, I saw your answer beat mine by 36 seconds. But mine is longer, so I'm going to call it a tie. :P – Aaron Jun 5 '11 at 20:36
I think I see it now! A little question because I haven't had enough sleep: is $\phi(\mathbb{R}^n\setminus x) = \phi(\mathbb{R}^n) \setminus \phi(x)$ a set theoretic result or is that specifically because $\phi$ is a homeomorphism? – Sputnik Jun 5 '11 at 20:37
@Fahad Sperinck That is completely set theoretic, using just that $\varphi$ is a bijection. If $\varphi^{-1}(\varphi(x))$ had more than one point, the map wouldn't work. However, the fact that restricted map is still a homeomorphism comes from the definition of the subspace topology. More generally, if $U\subset X$ and $\varphi:X\to Y$ is a homeomorphism, it restricts to a homeomorphism $U\to \varphi(U)$. – Aaron Jun 5 '11 at 20:45
Hint: Try removing a point and computing the homology.
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Thanks! This was there first and would have done the trick, but I read both at the same time. – Sputnik Jun 5 '11 at 20:40
Another possibility is to compare the one-point compactifications of $\mathbb{R}^n$ and $\mathbb{R}^m$, ie. $\mathbb{S}^n$ and $\mathbb{S}^m$ respectively, for example by computing the homology.
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https://physics.stackexchange.com/questions/53169/room-temperature-and-fan-orientation
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# Room temperature and fan orientation [duplicate]
So I'm in a tiny dorm room and I normally point my fan blowing outside the window to cool my room off. I've been in some debates on blowing air out or in is more effective, so I'm hoping to get some empirical data to back up my claim. Things I have
• A Heater with only low, medium, high settings.
• The Fan.
• I do not have a thermometer.
So the best I could think of was melting ice cubes. I don't care about the exact temperature, just which method is more effective.
I've outline the basis of my experiment:
Shut the windows and turn the heat on high, 15 minutes
Open the windows, turn off the heat, turn on the fan on high, 15 minutes
Leave $n$ ice cubes out and take the average of how long it takes them to melt.
All the ice cubes are from the same tray. Can anyone devise a better experiment with no tools...
• hackcollege.com/blog/2012/07/12/how-to-use-a-fan.html – raindrop Feb 6 '13 at 8:18
• Is the freezer (from which I assume you get your ice cubes) available for participation in your experiment (that is: in your room)? – Řídící Feb 6 '13 at 9:17
• Alternatively, do you perhaps share your room with (or can you borrow from a neighbour) a cockroach willing to assist you in your experiment? – Řídící Feb 6 '13 at 10:02
• Or a bottle of olive oil? – Řídící Feb 6 '13 at 10:35
• Yes to fridge and olive oil - No to cockroach. – zzzzzzzzzzz Feb 6 '13 at 17:36
(The OP has commented that the room also contains a fridge and a bottle of olive oil, but no cockroach.)
The viscosity of olive oil changes with temperature. At higher temperatures it becomes more fluid. If you first make sure that the olive oil has the current room temperature (pour it into a pan and back), you can then measure how fluid it is by letting light marbles fall in, or holding it upside down, and time it. You can repeat this for extra accuracy.
Too bad about the cockroach. Apparently its maximum speed goes up with the temperature (in the appropriate range of course).
And with the fridge you might try this. 1) Open its door until the motor starts, then shut the door until the motor stops. Then open the door and start blowing air in and time until the motor starts again. Repeat from 1), but now with blowing air out. (This will save you at least an hour compared to the original and other set-ups.)
• I like the idea with the fridge door. I attempted to do something similar with my heater, as it claims it has an "automatic" setting. You think the setting would work with all the tuition money I'm paying, but alas, it does not. – zzzzzzzzzzz Feb 7 '13 at 18:10
• Ha! But just to be clear: I actually meant blowing air into or out of the fridge (not the room)! So that your fridge becomes a(n even tinier) model of your room (with the temperature difference reversed of course, which shouldn't matter). – Řídící Feb 7 '13 at 18:27
You have to be precise on your experimental conditions.
Using the average time of melting ice cubes will work as a heat loss measure, as long as they are the same size icecubes and have been in the freezer the same time, though I am not sure about the temperature error width.
When blowing in air you should have the fan well outside the window. Usual fans have their blades shaped so they push air infront of them but not draw it from behind, so you should be sure to be blowing cool air in and not recirculating what is coming up to the window by convection back in.
Reverse is true for blowing out, there should be space in front of the blades where room air is pushed out and not outside window air.
Here is an article on natural cooling including use of fans. There exist window fans for taking air out of the room, or blowing it in.
• Blowing the air on you will be more effective, as it increases the convective heat transfer from your body to the room and thereby increasing the room temperature (provided your room is a closed or isolated system).
• The effect of blowing the air in or out of the room depends on the outside temperature. A fan is merely a device which increases mass transfer (and hence energy transfer too). Neglecting the waste heat generated by fan, there will be no appreciable change in the room temperature whether the fan blows air in or out.
• But blowing air on you is a different case where the convective heat transfer from your body to the surroundings will get enhanced by the fan.
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https://www.apguru.com/act-articles/miscellaneous-topics
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# Miscellaneous Topics
The ACT will probably contain two to three questions on each ACT test from a collection of additional topics. Even though none of the topics will not appear more than once on a test,collectively they could make a significant different to your ACT Math score.
# AP AND GP SERIES
For the purpose of the ACT, there are only TWO important series:
## 1. Arithmetic Progression
Consider these two common sequences
1,3, 5, 7, . . .
and
0, 10, 20, 30, 40, . . . .
It is easy to see how these sequences are formed. They each start with a particular first term, and then to get successive terms we just add a fixed value to the previous term. In the first sequence we add 2 to get the next term, and in the second sequence we add 10.
So the difference between consecutive terms in each sequence is a constant. We could also subtract a constant instead, because that is just the same as adding a negative constant.
Any sequence with this property is called an ARITHMETIC PROGRESSION, or AP for short
The following are the commonly used notations in an AP series:
• 'a’ stand for the first term of the sequence
• ‘d’ stand for the common difference between successive terms.
• 'n' stands for the nth term in the series
• 'Sn' stands for the sum of the first n terms in the series
If we wanted to write down the n-th term, we would have
EXAMPLE: An arithmetic progression has 3 as its first term. Also,the sum of the first 8 terms is twice the sum of the first 5 terms. Find the common difference.We are given that a = 3. We are given information about$$S_8$$ and $$S_5$$, and we want to find the common difference.
$$S_8$$ = (2a +(8-1)d) ---> $$S_8$$ = 4(2(3)+7d) and
$$S_5$$ =(2a +(5-1)d) ---> $$S_5$$ = (2(3)+4d)
So, using the given fact that $$S_8=2(S_5$$ , we see that
$$4(2(3)+7d)=2\cdot \frac{5}{2}(2(3)+4d)$$
$$8d=6$$
$$d=\frac{3}{4}$$
EXAMPLE 1:
Find the sum of all integers between 100 and 1000 which are divisible by 9.
A.55300
B.53500
C.55350
D.55530
Solution: The first integer greater than 100 and divisible by 9 is 108 and the integer just smaller than 1000 and divisible by 9 is 999. Thus, we have to find the sum of the series:
108 + 117 + 126 + …………. + 999.
Here,
$$a= 108;$$ $$d = 9;$$ $$a_n= 999$$
Using the formulae$$a_n = a + (n-1)d$$ ,we get
$$999= 108 + (9 - 1) d$$
$$n=100$$
To find the sum, we use the sum formulae:
$$S_n= (2a + (n-1)d) = (2(108) + (100-1)9) = 55350.$$
## 2. Geometric Progression
A GEOMETRIC PROGRESSION, or GP, is a sequence where each new term after the first is obtained by multiplying the preceding term by a constant ‘r’, called the common ratio. If the first term of the sequence is ‘a’ then the geometric progression is
$$a, ar, ar^2 , ar^3 , . . .$$
The n-th term is:
The sum of the terms of a geometric series is calculated by:
EXAMPLE: How many terms are there in the geometric progression 2, 4,8, . . ., 128?
In this sequence a = 2 and r = 2. We also know that the n-th term is 128. But the formula for the n-th term is $$ar^{n-1}$$ .
$$128 = 2\cdot 2^{n-1}$$
$$64 = 2^{n-1}$$
$$2^6=2^{n-1}$$
$$n = 7$$
EXAMPLE 2:
Since the beginning of 1990, the number of squirrels in a certain wooded area has tripled during every 3-year period of time. If there were 5,400 squirrels in the wooded area at the beginning of 1999, how many squirrels were in the wooded area at the beginning of 1990?
A.150
B.200
C.250
D.300
Solution: The number of squirrels triples every three years,so this is a geometric sequence. We first need to count how many times three years has passed between 1990 and 1999.Including the year 1990 and the year 1999, there are 4 terms for every 3 years between 1990 and 1999
1990,1993, 1996, 1999
This means that 1999 is our 4th term and 1990 is our 1st term. an = 5400, since there were 5400 squirrels in 1999.Now let’s plug in our values into our formula:
$$a_n=ar^{n-1}$$
$$a_n=a(3^{4-1})$$
$$5400 = a(27)$$
$$200 = a$$
# COMPLEX NUMBERS
Well there is a new “number” that we associate negative numbers under the square root. These are called COMPLEX NUMBERS, and they are indicated with the letter i, where:
We can do regular operations like addition, subtraction, multiplication, and division with complex numbers. Keep the following in mind, to make complex multiplication
simpler.
$$i=\sqrt{-1}$$
$$i^2=i\cdot i=\sqrt{-1}\cdot\sqrt{-1}=-1$$
$$i^3=i\cdot i\cdot i=\sqrt{-1}\cdot\sqrt{-1}\cdot \sqrt{-1} =-1\cdot \sqrt{-1}=-i$$
$$i^4=i^2\cdot i^2=-1\cdot -1=1$$
$$i^5=i^4\cdot i=1\cdot{i}=i$$
$$i^6=i^4\cdot i^2=1\cdot -1=-1$$
$$i^7=i^4\cdot i^3=-i$$
$$i^8=i^4\cdot i^4=1$$
EXAMPLE 3:
Find the value of $$i^{203}$$ ?
A. i
B. -i
C. 1
D. -1
Solution: Now, we need to first break up $$i^{203} \ to\ i^{202+1}$$
$$=i^{202}\cdot i^{1}$$
$$=(i^{2})^{101}\cdot i$$
$$= -1\times i$$
$$= -i$$
## Add & Subtract Complex Numbers
Adding and subtracting complex numbers is similar to adding and subtracting polynomials. Just add or subtract the real and imaginary parts.
EXAMPLE: Solve: (-6 - 5i) - (3 - 4i)
## Multiply Complex Numbers
Multiplying complex numbers is similar to multiplying polynomials.
EXAMPLE: Solve: (2 + 5i) (6 + 4i)
## Divide Complex Numbers
For complex division, we need to know what a conjugate is. For starters, all complex numbers take the form of a+ bi, where a is the x-coordinate and b is the y-coordinate. A complex conjugate is changing the + in a + bi to a − bi or vice versa. When we have complex division,we multiply by a clever form of “one,” which will be the conjugate of the denominator
EXAMPLE: Write each quotient in the form a + bi= $$\frac{6}{7-4i}$$
$$\frac{6}{7-4i}=\frac{6}{7-4i}\times\frac{7+4i}{7+4i}$$ To build an equivalent fraction, multiply by $$\frac{7+4i}{7+4i}=1$$
$$=\frac{42+24i}{49-16i^2}$$ To multiply the numerators, distribute the multiplication by 6.To multiply the denominators, find $$(7-4i)(7+4i)$$
$$=\frac{42+24i}{49-16(-1)}$$ Replace $$i^2$$ with $$-1$$. The denominator no longer contains i.
$$=\frac{42+24i}{65}$$ This notation represents the sum of two fractions that have the common denominator
$$=\frac{42}{65}+\frac{24}{65}i$$ Write the result in the form a + bi.
# MATRICES
A MATRIX is used to arrange number or data into rows and columns.
Here is an EXAMPLE of a matrix
$$\begin{bmatrix} 5&2\\ 4&-1 \\ -5&2 \end{bmatrix}$$
Matrices can be classified by listing first the number of rows then the number of columns. The matrix above is a 3x2 matrix because it has 3 rows and 2 columns.
The following matrix:
$$\begin{bmatrix} 3\\-8 \\ 7 \end{bmatrix}$$
is a 3x1 matrix because it has 3 rows and only 1 column.
Each number within a matrix is called an ENTRY.
Matrices are considered to be equal only if all the corresponding entries are equal. Thus
$$\begin{bmatrix} 2 & -1\\ 6 & 5 \end{bmatrix}=\begin{bmatrix} 2 & -1\\ 6 & 5 \end{bmatrix}$$
$$\begin{bmatrix} 7 & 0\\ -3 & 2 \end{bmatrix}=\begin{bmatrix} 7 & 0\\ -3 & 2 \end{bmatrix}$$
Matrices can only be added if they have the same number of rows and the same number of columns.
• Make sure they have the same number of rows and columns (or you cannot add them)
• Add or subtract each set of corresponding entries
EXAMPLE:
$$\begin{bmatrix} 6 & -5 & 6 \\ -3 & 4 & 7 \end{bmatrix} + \begin{bmatrix} 5 & 2 & 0 \\ -8 & -1 & 9 \end{bmatrix}=\begin{bmatrix} (6+5) & (-5+2) & (6+0) \\ (-3-8) & (4-1) & (7+9) \end{bmatrix}$$
# SETS
Translation problems which involve two or more given sets of data that partially intersect with each other are termed overlapping sets.
For EXAMPLE: 30 people are in a room. 20 of them play golf. 15 of them play golf and tennis.If everyone plays at least one of the two sports, how many of the people play tennis only?
This problem involves two sets: people who play golf and people who play tennis.
The two sets overlap because some of the people who play golf also play tennis. Thus, these two sets can actually be divided into four categories:
1. People who only play golf
2. People who only play tennis
3. People who play golf and tennis
4. People who play neither sport
Solving double-set ACT problems, such as in the example above, involves finding values for these four categories
## The Double-Set Matrix
For ACT problems involving only two categorizations or decisions, the most efficient tool is theDOUBLE-SET MATRIX, a table whose rows correspond to the options for one decision, and whose columns correspond to the options for the other decision.
The last row and the last column contain totals, so the bottom right corner contains the total number of everything or everyone in the problem.
Even if you are accustomed to using Venn diagrams for these problems, you should switch to the double-set matrix for problems with only two sets of options. The double-set matrix conveniently displays all possible combinations of options, including totals, whereas the Venn diagram only displays a few of them easily.
EXAMPLE: Of 30 integers, 15 are in set A, 22 are in set B, and 8 are in both set A and B. How many of the integers are in NEITHER set A nor set B?
Once the information given in the problem has been filled in, complete the chart, using the totals to guide you. (Each row and each column sum to a total value.)
The question asks for the number of integers that are in neither set. Look at the chart to find the number of integers that are NOT A and NOT B; you’ll find that the answer is 1.
WHEN YOU CONSTRUCT A DOUBLE-SET MATRIX, BE CAREFUL! As mentioned above, the rows should correspond to the mutually exclusive options for one decision. Likewise, the columns should correspond to the mutually exclusive options for the other.
For instance, if a problem deals with students getting either right or wrong answers on problems 1 and 2, the columns should not be “problem 1” and “problem 2,” and the rows should not be “right” and “wrong.” Instead, the columns should list options for one decision
• problem 1 correct, problem 1 incorrect, total
• and the rows should list options for the other decision
• problem 2 correct, problem 2 incorrect, total.
## Overlapping Sets and Percents
Many overlapping-sets problems involve percents or fractions. The double-set matrix is still effective on these problems, especially if you pick a SMART NUMBER for the grand total. For problems involving percents, pick a total of 100. For problems involving fractions, pick a common denominator for the total.
For EXAMPLE, pick 15 or 30 if the problem mentions categories that are 1/3 & 2/5 of the total.
EXAMPLE, 70% of the guests at Company X's annual holiday party are employees of Company X.10% of the guests are women who are not employees of Company X. If half the guests at the party are men, what percent of the guests are female employees of Company X?
First, fill in 100 for the total number of guests at the party. Then, fill in the other information given in the problem: 70% of the guests are employees, and 10% are women who are not employees. You also know that half the guests are men.
Next, calculate the rest of the information in the matrix:
100 - 70 = 30 guests who are not employees
30 - 10 = 20 men who are not employees
50 - 10 = 40 female employees
50 + 20 = 30 male employees
Thus, 40% of the guests at the party are female employees of Company X. Note: the problem doesn't require you to complete the matrix with the number of male employees. However,completing the matrix is an excellent way to check your computation. The last box you fill in must work both vertically and horizontally.
As in other problems involving Smart Numbers, you can only assign a number to the total if it is undetermined to start with. If the problem contains only fractions and/or percents, but no actual numbers of items or people, then go ahead and pick a total of 100 (for percent problems) or a common denominator (for fraction problems). But if actual quantities appear anywhere in the problem, then all the totals are already determined. In that case, you cannot assign numbers,but must solve for them instead.
## Overlapping Sets and Algebraic Expressions
When solving overlapping sets problems, you must pay close attention to the wording of the problem.
EXAMPLE: Santa estimates that 10% of the children in the world have been good this year but do not celebrate Christmas, and that 50% of the children who celebrate Christmas have been good this year. If 40% of the children in the world have been good, what percentage of children in the world are not good and do not celebrate Christmas?
It is tempting to fill in the number 50 to represent the percent of good children who celebrate Christmas. However, this approach is incorrect. Notice that you are told that 50% of the children who celebrate Christmas have been good.
This is different from being told that 50% of the children in the world have been good. In this problem, the information you have is a fraction of an unknown number. You do not yet know how many children celebrate Christmas.
Therefore, you cannot yet write a number for the good children who celebrate Christmas.Instead, you represent the unknown total number of children who celebrate Christmas with the variable x. Thus, you can represent the number of good children who celebrate Christmas with the expression 0.5x.
From the relationships in the table, you can set up an equation to solve for x:
0.5x + 10 = 40
x = 60
With this information, you can fill in the rest of the table:
Therefore, 30% of the children are not good and do not celebrate Christmas.
## 3-Set Problems: Venn Diagrams
Problems that involve three overlapping sets can be solved by using a Venn Diagram. The THREE OVERLAPPING SETS are usually three teams or clubs, and each person is either on or not on any given team or club.
For EXAMPLE: Workers are grouped by their areas of expertise and are placed on at least one team. There are 20 workers on the Marketing team, 30 on the Sales team, and 40 on the Vision team. 5 workers are on both the Marketing and Sales teams, 6 workers are on both the Sales and Vision teams, 9 workers are on both the Marketing and Vision teams, and 4 workers are on all three teams. How many workers are there in total?
In order to solve this problem, use a Venn Diagram. A Venn Diagram should be used ONLY for problems that involve three sets. Stick to the double-set matrix for two-set problems.
Begin your Venn Diagram by drawing three overlapping circles and labeling each one. Notice that there are seven different sections in a Venn Diagram. There is one innermost section (A) where all three circles overlap. This contains individuals who are on all three teams.
There are three sections (B, C, and D)
where two circles overlap. These
contain individuals who are on two
teams. There are three non-overlapping
sections (E, F, and G) that contain
individuals who are on only one team.
Venn Diagrams are easy to work with, if you remember one simple rule: WORK FROM THE INSIDE OUT.
That is, it is easiest to begin by filling in a number in the innermost section (A). Then, fill in numbers in the middle sections (B, C, and D). Fill in the outermost sections (E, F, and G) last.
1. Workers on all three teams. Fill in the innermost circle. This is given in the problem as 4.
2. Workers on two teams. Here you must remember to subtract those workers who are all three teams.
For EXAMPLE: the problem says that there
are 5 workers on the Marketing and Sales
teams. However, this includes the 4 workers
who are on all three teams. Therefore, in order
to determine the number of workers who are
on the Marketing and Sales teams exclusively,
you must subtract the 4 workers who are on
all three teams. You are left with 5 - 4 = 1 .
The number of workers on the Marketing and Vision teams exclusively is 9 - 4 = 5. The number of workers on the Sales and Vision teams exclusively is 6 - 4 = 2.
3. Workers on one team only. Here you must remember to subtract those workers who are on two teams and those workers who are on three teams. For EXAMPLE, the problem says that there are 20 workers on the Marketing team. But this includes the 1 worker who is on the Marketing and Sales teams, the 5 workers who are on the Marketing and Vision teams, and the 4 workers who are on all three teams. You must subtract all of these workers to find that there are 20 - 1 - 5 - 4 = 10 people who are on the Marketing team exclusively. There are 30 - 1 - 2 - 4 = 23 people on the Sales team exclusively.
There are 40 - 2 - 5 - 4 = 29
people on the Vision team
exclusively. In order to determine
the total, just add all seven
numbers together = 74
total workers.
# PATTERNS
Some problem-types on the ACT are practically impossible to solve if you’ve never seen them before, but insanely easy to solve once you’ve done them once or twice. The following “sequence identification” problem-type is one such problem type.
In the context of the ACT, PATTERN RECOGNITION involves spotting a repeating cycle or other simple relationship underlying a series of numbers. If you can grasp the rule, you can predict numbers that appear later in the series. The series may be part of a defined sequence, or it may arise from a general list of possibilities.
Here's a simple EXAMPLE: If Today is Tuesday, what day will it be 300 days from now?
Uuuuuuhhhh…..how the heck could I ever solve this? Do they expect me to count till 300 days ago?
No, But you can answer this question in literally two seconds if I know how too. The answer is MONDAY. Here’s how I know that:
1. I figure out how many terms are in the sequence before it starts to repeat. In this case, there are 7 since there are seven days in a week.
2. I figure out the closest number to my target number divisible by the answer to #1. In other words, what’s the closest number to 300 that’s divisible by 7? That is 294. That will be the last term in my sequence -> Monday in our example. Therefore the 294thterm will be Monday.
3. Count manually until you get to the one you’re looking for. Therefore, 295th term is Tuesday, the 296th term is Wednesday, 297th term is Thursday, 298th term is Friday,299th term is Saturday and 300th Term is Monday.
In the following sequence: A, B, C, D, E, F, A, B, C, D, E, F, what is the 602nd term?
A. A
B. B
C. D
D. F
Solution: Since there are 6 terms in this sequence, anything divisible by 6 will be F, the last term of the sequence!
600 is divisible by 6, which means that F is the 600th term. Now we just count manually. 600 is F, 601 is A, 602 is B - done! Therefore, the correct answer is B.
This trick ONLY works with the LAST term of the sequence.
You need to think of the entire pattern as one giant unit that can’t be broken up. Try these two problems on your own, and look at the answer explanations if you have any trouble:
EXAMPLE: In the following sequence: 1, 2, 2, 0, 4, 1, 2, 2, 0, 4, 1, 2, 2, 0, 4 (repeated indefinitely),
what is the sum of the first 613 terms of this sequence?
1. Figure out what the sequence looks like. “1, 2, 2, 0, 4” - that’s the unit that repeats. There are 5 terms in this sequence
2. Figure out the sum of that sequence. 1 + 2 + 2 + 0 + 4 = 9. So for every 5 terms, you have a sum of “9”
3. Divide 613 by 5. We get 122.6
4. Realize that this sequence repeats itself in full 122 times. So multiply 122 by the sum of the sequence, which is 9, and we get: 122 x 9 = 1,098
5. Get rid of the “.6” at the end of 122 and multiply that by 5. 122 x 5 = 610. That means that the sum of the first 610 terms is 1,098
6. Count manually from 610. We still have terms 611, 612, and 613 to go, which are 1, 2, and 2, respectively. So we add 1 + 2 + 2 =5 to our former total, 1,098, and we get 1,103.
EXAMPLE 5:
In the following sequence, A, B, C, D, E, F, G, H (repeated indefinitely), what’s the 456,791st term?
A. A
B. D
C. F
D. G
Solution:
1. Count the term numbers: There are 8
2. Divide 456,791 by 8. We get 57,098.875
3. Get rid of the “.875”
4. Multiply the remainder by 8. 57,098 x 8 = 456,784.
5. Count manually. 456,784 = H, 456,785 = A, 456,786 = B, 456,787 = C, 456,788 = D, 456,789 = E,
456,790 = F, 456,791 = G. The correct answer is C
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This New BOOK will go through the the 50 Most Common Topics tested on the SAT in detail.
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https://www.mysciencework.com/publication/show/spin-squeezing-transforming-one-axis-twisting-two-axis-twisting-380ac643
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# Spin squeezing: transforming one-axis-twisting into two-axis-twisting
Authors
Type
Published Article
Publication Date
May 02, 2011
Submission Date
May 02, 2011
Identifiers
DOI: 10.1103/PhysRevLett.107.013601
Source
arXiv
Squeezed spin states possess unique quantum correlation or entanglement that are of significant promises for advancing quantum information processing and quantum metrology. In recent back to back publications [C. Gross \textit{et al, Nature} \textbf{464}, 1165 (2010) and Max F. Riedel \textit{et al, Nature} \textbf{464}, 1170 (2010)], reduced spin fluctuations are observed leading to spin squeezing at -8.2dB and -2.5dB respectively in two-component atomic condensates exhibiting one-axis-twisting interactions (OAT). The noise reduction limit for the OAT interaction scales as $\propto 1/{N^{2/3}}$, which for a condensate with $N\sim 10^3$ atoms, is about 100 times below standard quantum limit. We present a scheme using repeated Rabi pulses capable of transforming the OAT spin squeezing into the two-axis-twisting type, leading to Heisenberg limited noise reduction $\propto 1/N$, or an extra 10-fold improvement for $N\sim 10^3$.
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https://www.gradesaver.com/textbooks/math/algebra/algebra-1/chapter-10-radical-expressions-and-equations-10-4-solving-radical-equations-practice-and-problem-solving-exercises-page-624/26
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## Algebra 1
Published by Prentice Hall
# Chapter 10 - Radical Expressions and Equations - 10-4 Solving Radical Equations - Practice and Problem-Solving Exercises - Page 624: 26
#### Answer
$n=-4$ is extraneous
#### Work Step by Step
$Given,$ $\sqrt (12-n)=n$ Checking for $n=-4$ : $L.H.S=\sqrt (12-(-4))=\sqrt 16=4$ $R.H.S=-4$ $L.H.S$ does not equal $R.H.S$,hence $n=-4$ is extraneous Checking for $n=3$: $L.H.S=\sqrt (12-3)=\sqrt 9=3$ $R.H.S=3$ $L.H.S=R.H.S$,hence $n=3$ is not extraneous
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http://openstudy.com/updates/56034c8fe4b07350e00baeb2
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## anonymous one year ago Write the equation in slope-intercept form. slope=1/2 and the y intercept is (0,6) Walk me through this please!! Delete Cancel Submit
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1. anonymous
• one year ago
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The slope-intercept form is: $$y=mx+b$$, where $$m$$ is the slope. So $$m=\frac{1}{2}$$. We also have a point $$(0,6)$$. This point is your x-intercept and y-intercept. $$x=0$$ and $$y=6$$ So we have $$y$$, $$x$$, and $$m$$, but we don't have the $$b$$. Plug in what's given to the slope-intercept form to solve for $$b$$. $$y=mx+b$$ $$6=(\frac{1}{2})(0)+b$$ $$b=6$$.
2. anonymous
• one year ago
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y = 1/2 + 6?? or do I incorporate the 0
3. anonymous
• one year ago
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We already have the things we need, so we should now write it in $${slope-intercept form$$. $$\huge m=\frac {1}{2}$$ and $$\huge b=6$$. $$\huge y=mx+b$$ $$\huge y=\frac {1}{2}x+6$$
4. anonymous
• one year ago
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ahhh okay I see, that's what I thought I was just unsure if I add in the 0 or not. Can you please help me on another equation? I'm having trouble on the placements
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http://www.science.gov/topicpages/m/magnetic+dipole+electric.html
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#### Sample records for magnetic dipole electric
1. Electric dipoles on magnetic monopoles in spin ice.
PubMed
Khomskii, D I
2012-01-01
The close connection of electricity and magnetism is one of the cornerstones of modern physics. This connection has a crucial role from a fundamental point of view and in practical applications, including spintronics and multiferroic materials. A breakthrough was a recent proposal that in magnetic materials called spin ice the elementary excitations have a magnetic charge and behave as magnetic monopoles. I show that, besides magnetic charge, there should be an electric dipole attached to each magnetic monopole. This opens new possibilities to study and control such monopoles using an electric field. Thus, the electric-magnetic analogy goes even further than usually assumed: whereas electrons have electric charge and magnetic dipole (spin), magnetic monopoles in spin ice, while having magnetic charge, also have an electric dipole. PMID:22713746
2. Electric and magnetic dipole couplings in split ring resonator metamaterials
NASA Astrophysics Data System (ADS)
Fan, Jing; Sun, Guang-Yong; Zhu, Wei-Ren
2011-11-01
In this paper, the electric and the magnetic dipole couplings between the outer and the inner rings of a single split ring resonator (SRR) are investigated. We numerically demonstrate that the magnetic resonance frequency can be substantially modified by changing the couplings of the electric and magnetic dipoles, and give a theoretical expression of the magnetic resonance frequency. The results in this work are expected to be conducive to a deeper understanding of the SRR and other similar metamaterials, and provide new guidance for complex metamaterials design with a tailored electromagnetic response.
3. Magnetic and electric dipoles for physics beyond the standard model
NASA Astrophysics Data System (ADS)
Heo, Jae Ho
The magnetic and electric dipole moments of particles have been significant topics to explore physics beyond the standard model. The anomalous magnetic dipole moment of the muon has shown a sizable deviation from the standard model prediction. Many people consider that the deviation comes from new physics beyond the standard model, so it provides a significance for new physics beyond the standard model. We discuss its significance by building a model in the standard model extension. The search for the electric dipole will uncover the violation of one of the fundamental discrete symmetries, CP violation. The charged leptons do not have CP violating interactions in the standard model. A lepton electric dipole moment is induced by the CKM phase in the quark sector via a diagram with a closed quark loop, so any positive detection of an electric dipole moment will imply the presence of a non-CKM CP violating source and lead to the scale of new physics. We consider new CP violating sources, and predictions of the sizable electric dipole moments are discussed. Finally, Dirac fermionic dark matter near the electroweak scale with nonzero dipoles is introduced and its implications are discussed. In addition, QCD radiative corrections to pair annihilation of spin-1 bosonic dark matter is presented and we show that the radiative correction can play a significant role to analyze dark matter phenomenology for the certain models.
4. Atomic electric dipole moment induced by the nuclear electric dipole moment: The magnetic moment effect
SciTech Connect
Porsev, S. G.; Ginges, J. S. M.; Flambaum, V. V.
2011-04-15
We have considered a mechanism for inducing a time-reversal violating electric dipole moment (EDM) in atoms through the interaction of a nuclear EDM d{sub N} with the hyperfine interaction, the ''magnetic moment effect''. We have derived the operator for this interaction and presented analytical formulas for the matrix elements between atomic states. Induced EDMs in the diamagnetic atoms {sup 129}Xe, {sup 171}Yb, {sup 199}Hg, {sup 211}Rn, and {sup 225}Ra have been calculated numerically. From the experimental limits on the atomic EDMs of {sup 129}Xe and {sup 199}Hg we have placed the following constraints on the nuclear EDMs, |d{sub N}({sup 129}Xe)|<1.1x10{sup -21}|e|cm and |d{sub N}({sup 199}Hg)|<2.8x10{sup -24}|e|cm.
5. Thermodynamics of a continuous medium with electric and magnetic dipoles
NASA Astrophysics Data System (ADS)
Brechet, Sylvain D.; Ansermet, Jean-Philippe
2013-07-01
The thermodynamics of an electrically charged, multicomponent fluid with spontaneous electric and magnetic dipoles is analysed in the presence of electromagnetic fields. Taking into account the chemical composition of the current densities and stress tensors leads to three types of irreversible terms: scalars, vectors and pseudo-vectors. The scalar terms account for chemical reactivities, the vectorial terms account for transport and the pseudo-vectorial terms account for relaxation. The linear phenomenological relations, derived from the irreversible evolution, describe notably the Lehmann and electric Lehmann effects, the Debye relaxation of polar molecules and the Landau-Lifshitz relaxation of the magnetisation. This formalism accounts for the thermal and electric magnetisation accumulations and magnetisation waves. It also predicts that a temperature gradient affects the dynamics of magnetic vortices and drives magnetisation waves.
6. Magnetic Shielding Studies for Electric Dipole Moment Experiments
NASA Astrophysics Data System (ADS)
Gould, Harvey; Feinberg, B.
2014-09-01
Electric dipole moment experiments are necessarily sensitive to magnetic fields and hence require effective magnetic shielding. In testing the shielding factor of single-layer Permalloy (Carpenter HyMu 80'' ®) cylinders, we find time-dependent effects lasting tens of minutes to thousands of minutes when a static magnetic field is applied to a Permalloy cylinder that has been demagnetized in a region of near-zero field. A decrease in the magnetic field, measured at the center of the cylinder, of about 20 percent is observed for applied fields ranging from 0.5 A/m to 16 A/m. The latter applied field is comparable to the Earth's magnetic field. Effects that resemble these have been seen in other ferromagnetic materials.
7. Dynamically fluctuating electric dipole moments in fullerene-based magnets.
PubMed
Kambe, Takashi; Oshima, Kokichi
2014-01-01
We report here the direct evidence of the existence of a permanent electric dipole moment in both crystal phases of a fullerene-based magnet--the ferromagnetic α-phase and the antiferromagnetic α'-phase of tetra-kis-(dimethylamino)-ethylene-C60 (TDAE-C60)--as determined by dielectric measurements. We propose that the permanent electric dipole originates from the pairing of a TDAE molecule with surrounding C60 molecules. The two polymorphs exhibit clear differences in their dielectric responses at room temperature and during the freezing process with dynamically fluctuating electric dipole moments, although no difference in their room-temperature structures has been previously observed. This result implies that two polymorphs have different local environment around the molecules. In particular, the ferromagnetism of the α-phase is founded on the homogeneous molecule displacement and orientational ordering. The formation of the different phases with respect to the different rotational states in the Jahn-Teller distorted C60s is also discussed. PMID:25236361
8. Electron scattering in graphene by impurities with electric and magnetic dipole moments
NASA Astrophysics Data System (ADS)
Mal'nev, V. N.; Senbeta, Teshome; Achenefe, Yohannes
2014-06-01
The elastic electron scattering by impurities with electric and magnetic dipoles in graphene is studied with the help of Born approximation. Both types of scatterers give the nonzero cross section of backscattering. The scattering by the impurities with electric dipoles is more efficient even comparing to the scattering by the nanomagnets with anomalous magnetic moments. A comparison of the electron scattering transport cross sections by charged impurities and impurities with electric dipole moments shows that they can be comparable. The scattering by the impurities electric dipoles can be important in limiting the electron mobility in graphene along with the Coulomb scattering.
9. Electric charge is a magnetic dipole when placed in a background magnetic field
NASA Astrophysics Data System (ADS)
Adorno, T. C.; Gitman, D. M.; Shabad, A. E.
2014-02-01
It is demonstrated, owing to the nonlinearity of QED, that a static charge placed in a strong magnetic field B is a magnetic dipole (besides remaining an electric monopole, as well). Its magnetic moment grows linearly with B as long as the latter remains smaller than the characteristic value of 1.2×1013 G but tends to a constant as B exceeds that value. The force acting on a densely charged object by the dipole magnetic field of a neutron star is estimated.
10. Modeling and analysis of optical properties of a gold nanoring based on electric and magnetic dipoles.
PubMed
Safaee, S M R; Janipour, M; Karami, M A
2015-10-01
The optical behavior of a plane-wave excited gold nanoring (NR), originated from localized surface plasmon resonance is modeled by two coupled electric- and magnetic-point dipoles. Considering the extinction cross-section spectrum, it is found that the electric-dipole effect is dominant in comparison with the magnetic-dipole effect although the magnetic-dipole signature is observable in the near-field response of the NR. In addition, the far-field electromagnetic radiation pattern of the NR verifies the corresponding radiation pattern of the point dipoles. The numerical simulation near-field results are in agreement with the proposed electric- and magnetic-dipole theory. PMID:26479602
11. Controlling magnetic and electric dipole modes in hollow silicon nanocylinders.
PubMed
van de Haar, Marie Anne; van de Groep, Jorik; Brenny, Benjamin J M; Polman, Albert
2016-02-01
We propose a dielectric nanoresonator geometry consisting of hollow dielectric nanocylinders which support geometrical resonances. We fabricate such hollow Si particles with an outer diameter of 108-251 nm on a Si substrate, and determine their resonant modes with cathodo-luminescence (CL) spectroscopy and optical dark-field (DF) scattering measurements. The scattering behavior is numerically investigated in a systematic fashion as a function of wavelength and particle geometry. We find that the additional design parameter as a result of the introduction of a center gap can be used to control the relative spectral spacing of the resonant modes, which will enable additional control over the angular radiation pattern of the scatterers. Furthermore, the gap offers direct access to the enhanced magnetic dipole modal field in the center of the particle. PMID:26906780
12. A prototype vector magnetic field monitoring system for a neutron electric dipole moment experiment
NASA Astrophysics Data System (ADS)
Nouri, N.; Biswas, A.; Brown, M. A.; Carr, R.; Filippone, B.; Osthelder, C.; Plaster, B.; Slutsky, S.; Swank, C.
2015-12-01
We present results from a first demonstration of a magnetic field monitoring system for a neutron electric dipole moment experiment. The system is designed to reconstruct the vector components of the magnetic field in the interior measurement region solely from exterior measurements.
13. Electric dipole moments, cluster metallicity, and the magnetism of rare earth clusters
NASA Astrophysics Data System (ADS)
Bowlan, John
One of the fundamental properties of bulk metals is the cancellation of electric fields. The free charges inside of a metal will move until they find an arrangement where the internal electric field is zero. This implies that the electric dipole moment of a metal particle should be exactly zero, because an electric dipole moment requires a net separation of charge and thus a nonzero internal electric field. This thesis is an experimental study to see if this property continues to hold for tiny subnanometer metal particles called clusters (2--200 atom, R < 1 nm). We have measured the electric dipole moments of metal clusters made from 15 pure elements using a molecular beam electric deflection technique. We find that the observed dipole moments vary a great deal across the periodic table. Alkali metals have zero dipole moments, while transition metals and lanthanides all have dipole moments which are highly size dependent. In most cases, the measured dipole moments are independent of temperature (T = 20--50 K), and when there is a strong temperature dependence this suggests that there is a new state of matter present. Our interpretation of these results are that those clusters which have a nonzero dipole moment are non-metallic, in the sense that their electrons must be localized and prevented from moving to screen the internal field associated with a permanent dipole moment. This interpretation gives insight to several related phenomena and applications. We briefly discuss an example cluster system RhN where the measured electric dipole moments appear to be correlated with a the N2O reactivity. Finally, we discuss a series of magnetic deflection experiments on lanthanide clusters (Pr, Ho, Tb, and Tm). The magnetic response of these clusters is very complex and highly sensitive to size and temperature. We find that PrN (which is non-magnetic in the bulk) becomes magnetic in clusters and Tm N clusters have magnetic moments lower than the atomic value as well as the bulk saturation value implying that the magnetic order in the cluster involves non-collinear or antiferromagnetic order. HoN and TbN show very similar size dependent trends suggesting that these clusters have similar structures.
14. Modification of electric and magnetic dipole emission in anisotropic plasmonic systems
NASA Astrophysics Data System (ADS)
Noginova, N.; Hussain, R.; Noginov, M. A.; Vella, J.; Urbas, A.
Spontaneous emission of a dipole can be significantly modified in metamaterials, providing opportunities to engineer emission rates, yields, spectra, and angular patterns. To better understand specifics of such modifications for electric and magnetic emitters, we study luminescence of Eu3+ ions placed in a close vicinity of arrays of gold nanostrips. The luminescence is strongly polarized, with the preferable polarization parallel to the direction of strips. Polarization patterns and angular distributions of radiation depend on wavelength, and are different for electric and magnetic dipole transitions. The results are discussed in terms of different coupling of emitters with radiative and high-loss modes.
15. Magnetic and electric dipole moments of the H 3?1 state in ThO
NASA Astrophysics Data System (ADS)
Vutha, A. C.; Spaun, B.; Gurevich, Y. V.; Hutzler, N. R.; Kirilov, E.; Doyle, J. M.; Gabrielse, G.; Demille, D.
2011-09-01
The metastable H3?1 state in the thorium monoxide (ThO) molecule is highly sensitive to the presence of a CP-violating permanent electric dipole moment of the electron (eEDM) [E. R. Meyer and J. L. Bohn, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.78.010502 78, 010502 (2008)]. The magnetic dipole moment ?H and the molecule-fixed electric dipole moment DH of this state are measured in preparation for a search for the eEDM. The small magnetic moment ?H=8.5(5)10-3?B displays the predicted cancellation of spin and orbital contributions in a 3?1 paramagnetic molecular state, providing a significant advantage for the suppression of magnetic field noise and related systematic effects in the eEDM search. In addition, the induced electric dipole moment is shown to be fully saturated in very modest electric fields (<10 V/cm). This feature is favorable for the suppression of many other potential systematic errors in the ThO eEDM search experiment.
16. Electric and Magnetic Dipole Coupling in Near-Infrared Split-Ring Metamaterial Arrays
NASA Astrophysics Data System (ADS)
Sersic, Ivana; Frimmer, Martin; Verhagen, Ewold; Koenderink, A. Femius
2009-11-01
We present experimental observations of strong electric and magnetic interactions between split ring resonators (SRRs) in metamaterials. We fabricated near-infrared planar metamaterials with different inter-SRR spacings along different directions. Our transmission measurements show blueshifts and redshifts of the magnetic resonance, depending on SRR orientation relative to the lattice. The shifts agree well with simultaneous magnetic and electric near-field dipole coupling. We also find large broadening of the resonance, accompanied by a decrease in effective cross section per SRR with increasing density due to superradiant scattering. Our data shed new light on Lorentz-Lorenz approaches to metamaterials.
17. Electric and magnetic dipole coupling in near-infrared split-ring metamaterial arrays.
PubMed
Sersic, Ivana; Frimmer, Martin; Verhagen, Ewold; Koenderink, A Femius
2009-11-20
We present experimental observations of strong electric and magnetic interactions between split ring resonators (SRRs) in metamaterials. We fabricated near-infrared planar metamaterials with different inter-SRR spacings along different directions. Our transmission measurements show blueshifts and redshifts of the magnetic resonance, depending on SRR orientation relative to the lattice. The shifts agree well with simultaneous magnetic and electric near-field dipole coupling. We also find large broadening of the resonance, accompanied by a decrease in effective cross section per SRR with increasing density due to superradiant scattering. Our data shed new light on Lorentz-Lorenz approaches to metamaterials. PMID:20366039
18. Stark Interference of Electric and Magnetic Dipole Transitions in the A -X Band of OH
NASA Astrophysics Data System (ADS)
Schewe, H. Christian; Zhang, Dongdong; Meijer, Gerard; Field, Robert W.; Sartakov, Boris G.; Groenenboom, Gerrit C.; van der Avoird, Ad; Vanhaecke, Nicolas
2016-04-01
An experimental method is demonstrated that allows determination of the ratio between the electric (E 1 ) and magnetic (M 1 ) transition dipole moments in the A -X band of OH, including their relative sign. Although the transition strengths differ by more than 3 orders of magnitude, the measured M 1 -to-E 1 ratio agrees with the ratio of the ab initio calculated values to within 3%. The relative sign is found to be negative, also in agreement with theory.
19. Modelling the magnetic dipole
NASA Astrophysics Data System (ADS)
Seleznyova, Kira; Strugatsky, Mark; Kliava, Janis
2016-03-01
Three different models of a magnetic dipole, viz., a uniformly magnetised sphere, a circular current loop and a pair of fictitious magnetic charges, have been systematically analysed within the formalism based on the vector potential of the magnetic field. The expressions of the potentials and magnetic fields produced by each dipole model have been obtained. A computer code has been put forward in order to visualise magnetic field lines for different dipole models. It has been shown that the magnetic field outside the uniformly magnetised sphere coincides with that of a point dipole. The other two models give considerably different results at distances small or intermediate in comparison with the dipole size.
20. Lepton electric and magnetic dipole moments via lepton flavor-violating spin-1 unparticle interactions
SciTech Connect
Moyotl, A.; Rosado, A.; Tavares-Velasco, G.
2011-10-01
The magnetic dipole moment and the electric dipole moment of leptons are calculated under the assumption of lepton flavor violation (LFV) induced by spin-1 unparticles with both vector and axial-vector couplings to leptons, including a CP-violating phase. The experimental limits on the muon magnetic dipole moment and LFV process, such as the decay l{sub i}{sup -}{yields}l{sub j}{sup -}l{sub k}{sup -}l{sub k}{sup +}, are then used to constrain the LFV couplings for particular values of the unparticle operator dimension d{sub U} and the unparticle scale {Lambda}{sub U}, assuming that LFV transitions between the tau and muon leptons are dominant. It is found that the current experimental constraints favor a scenario with dominance of the vector couplings over the axial-vector couplings. We also obtain estimates for the electric dipole moments of the electron and the muon, which are well below the experimental values.
1. Electric and magnetic dipoles in the Lorentz and Einstein-Laub formulations of classical electrodynamics
NASA Astrophysics Data System (ADS)
Mansuripur, Masud
2015-01-01
The classical theory of electrodynamics cannot explain the existence and structure of electric and magnetic dipoles, yet it incorporates such dipoles into its fundamental equations, simply by postulating their existence and properties, just as it postulates the existence and properties of electric charges and currents. Maxwell's macroscopic equations are mathematically exact and self-consistent differential equations that relate the electromagnetic (EM) field to its sources, namely, electric charge-density 𝜌𝜌free, electric current-density 𝑱𝑱free, polarization 𝑷𝑷, and magnetization 𝑴𝑴. At the level of Maxwell's macroscopic equations, there is no need for models of electric and magnetic dipoles. For example, whether a magnetic dipole is an Amperian current-loop or a Gilbertian pair of north and south magnetic monopoles has no effect on the solution of Maxwell's equations. Electromagnetic fields carry energy as well as linear and angular momenta, which they can exchange with material media—the seat of the sources of the EM field—thereby exerting force and torque on these media. In the Lorentz formulation of classical electrodynamics, the electric and magnetic fields, 𝑬𝑬 and 𝑩𝑩, exert forces and torques on electric charge and current distributions. An electric dipole is then modeled as a pair of electric charges on a stick (or spring), and a magnetic dipole is modeled as an Amperian current loop, so that the Lorentz force law can be applied to the corresponding (bound) charges and (bound) currents of these dipoles. In contrast, the Einstein-Laub formulation circumvents the need for specific models of the dipoles by simply providing a recipe for calculating the force- and torque-densities exerted by the 𝑬𝑬 and 𝑯𝑯 fields on charge, current, polarization and magnetization. The two formulations, while similar in many respects, have significant differences. For example, in the Lorentz approach, the Poynting vector is 𝑺𝑺𝐿𝐿 = 𝜇𝜇0 -1𝑬𝑬 × 𝑩𝑩, and the linear and angular momentum densities of the EM field are 𝓹𝓹𝐿𝐿 = 𝜀𝜀0𝑬𝑬 × 𝑩𝑩 and 𝓛𝓛𝐿𝐿 = 𝒓𝒓 × 𝓹𝓹𝐿𝐿, whereas in the Einstein-Laub formulation the corresponding entities are 𝑺𝑺𝐸𝐸𝐸𝐸= 𝑬𝑬 × 𝑯𝑯, 𝓹𝓹𝐸𝐸𝐸𝐸= 𝑬𝑬 × 𝑯𝑯⁄𝑐𝑐2, and 𝓛𝓛𝐸𝐸𝐸𝐸= 𝒓𝒓 × 𝓹𝓹𝐸𝐸𝐸𝐸. (Here 𝜇𝜇0 and 𝜀𝜀0 are the permeability and permittivity of free space, 𝑐𝑐 is the speed of light in vacuum, 𝑩𝑩 = 𝜇𝜇0𝑯𝑯 + 𝑴𝑴, and 𝒓𝒓 is the position vector.) Such differences can be reconciled by recognizing the need for the so-called hidden energy and hidden momentum associated with Amperian current loops of the Lorentz formalism. (Hidden entities of the sort do not arise in the Einstein-Laub treatment of magnetic dipoles.) Other differences arise from over-simplistic assumptions concerning the equivalence between free charges and currents on the one hand, and their bound counterparts on the other. A more nuanced treatment of EM force and torque densities exerted on polarization and magnetization in the Lorentz approach would help bridge the gap that superficially separates the two formulations. Atoms and molecules may collide with each other and, in general, material constituents can exchange energy, momentum, and angular momentum via direct mechanical interactions. In the case of continuous media, elastic and hydrodynamic stresses, phenomenological forces such as those related to exchange coupling in ferromagnets, etc., subject small volumes of materials to external forces and torques. Such matter-matter interactions, although fundamentally EM in nature, are distinct from field-matter interactions in classical physics. Beyond the classical regime, however, the dichotomy that distinguishes the EM field from EM sources gets blurred. An electron's wavefunction may overlap that of an atomic nucleus, thereby initiating a contact interaction between the magnetic dipole moments of the two particles. Or a neutron passing through a ferromagnetic material may give rise to scattering events involving overlaps between the wave-functions of the neutron and magnetic electrons. Such matter-matter interactions exert equal and opposite forces and/or torques on the colliding particles, and their observable effects often shed light on the nature of the particles involved. It is through such observations that the Amperian model of a magnetic dipole has come to gain prominence over the Gilbertian model. In situations involving overlapping particle wave-functions, it is imperative to take account of the particle-particle interaction energy when computing the scattering amplitudes. As far as total force and total torque on a given volume of material are concerned, such particle-particle interactions do not affect the outcome of calculations, since the mutual actions of the two (overlapping) particles cancel each other out. Both Lorentz and Einstein-Laub formalisms thus yield the same total force and total torque on a given volume—provided that hidden entities are properly removed. The Lorentz formalism, with its roots in the Amperian current-loop model, correctly predicts the interaction energy between two overlapping magnetic dipoles 𝒎𝒎1 and 𝒎𝒎2 as being proportional to -𝒎𝒎1 • 𝒎𝒎2. In contrast, the Einstein-Laub formalism, which is ignorant of such particle-particle interactions, needs to account for them separately.
2. Generation of ULF waves by electric or magnetic dipoles. [propagation from earth surface to ionosphere
NASA Technical Reports Server (NTRS)
Harker, K. J.
1975-01-01
The generation of ULF waves by ground-based magnetic and electric dipoles is studied with a simplified model consisting of three adjoining homogeneous regions representing the groud, the vacuum (free space) region, and the ionosphere. The system is assumed to be immersed in a homogeneous magnetic field with an arbitrary tilt angle. By the use of Fourier techniques and the method of stationary phase, analytic expressions are obtained for the field strength of the compressional Alfven waves in the ionosphere. Expressions are also obtained for the strength of the torsional Alfven wave in the ionosphere and the ULF magnetic field at ground level. Numerical results are obtained for the compressional Alfven-wave field strength in the ionosphere with a nonvertical geomagnetic field and for the ULF magnetic field at ground level for a vertical geomagnetic field.
3. Magnetic g_e-FACTORS and Electric Dipole Moments of Lanthanide Monoxides: PrO
NASA Astrophysics Data System (ADS)
Wang, Hailing; Steimle, Timothy C.; Linton, Colan
2009-06-01
The very complex optical spectra of the lanthanide monoxides are caused by the insensitivity of the electronic energies to the numerous possible arrangements of the Ln^{2+} electrons in the 4f and 6s orbitals. Disentangling the complex optical spectra may be aided by using simple Ligand Field Theory(LFT) to establish the global electronic structure for the low-lying electronic states. A comparison of experimentally determined permanent electric dipole moments, μ_{el}, and magnetic dipole moments, μ_{m}, is an effective means of sorting this myriad of states and assessing the quality of LFT and other electronic structure methodologies. Here we report on the determination of the permanent electric dipole moments, μ_{el}, and magnetic g{_e}-factors for the X_{2}(Ω = 4.5) and [18.1] (Ω = 5.5) states of PrO from the analysis of the optical Stark and Zeeman spectra. The g_{e}-factors are compared with those computed using wavefunctions predicted from ligand field theory. The μ_{el} value for the X_{2}(Ω = 4.5) state is compared to ab initio, and density functional predictions and with the experimental values of other lanthanide monoxides. A phenomenological fit of μ_{el} for the entire series of LnO is used to predict μ_{el} for the isovalent actinide monoxide series. Carette, P.,; Hocquet,A. J. Mol. Spectrosc. 131 301, 1988. Dolg, M.; Stoll, H. Theor. Chim. Acta. 75,369, 1989. Wu, Z.; Guan, W. Meng, J. Su, Z. J. Cluster Science 18 444, 2007.
4. Nuclear Magnetic Dipole and Electric Quadrupole Moments: Their Measurement and Tabulation as Accessible Data
NASA Astrophysics Data System (ADS)
Stone, N. J.
2015-09-01
The most recent tabulations of nuclear magnetic dipole and electric quadrupole moments have been prepared and published by the Nuclear Data Section of the IAEA, Vienna [N. J. Stone, Report No. INDC(NDS)-0650 (2013); Report No. INDC(NDS)-0658 (2014)]. The first of these is a table of recommended quadrupole moments for all isotopes in which all experimental results are made consistent with a limited number of adopted standards for each element; the second is a combined listing of all measurements of both moments. Both tables cover all isotopes and energy levels. In this paper, the considerations relevant to the preparation of both tables are described, together with observations as to the importance and (where appropriate) application of necessary corrections to achieve the "best" values. Some discussion of experimental methods is included with emphasis on their precision. The aim of the published quadrupole moment table is to provide a standard reference in which the value given for each moment is the best available and for which full provenance is given. A table of recommended magnetic dipole moments is in preparation, with the same objective in view.
5. Magnetic and electric dipole moments of the H {sup 3}{Delta}{sub 1} state in ThO
SciTech Connect
Vutha, A. C.; Kirilov, E.; DeMille, D.; Spaun, B.; Gurevich, Y. V.; Hutzler, N. R.; Doyle, J. M.; Gabrielse, G.
2011-09-15
The metastable H {sup 3}{Delta}{sub 1} state in the thorium monoxide (ThO) molecule is highly sensitive to the presence of a CP-violating permanent electric dipole moment of the electron (eEDM) [E. R. Meyer and J. L. Bohn, Phys. Rev. A 78, 010502 (2008)]. The magnetic dipole moment {mu}{sub H} and the molecule-fixed electric dipole moment D{sub H} of this state are measured in preparation for a search for the eEDM. The small magnetic moment {mu}{sub H}=8.5(5)x10{sup -3} {mu}{sub B} displays the predicted cancellation of spin and orbital contributions in a {sup 3}{Delta}{sub 1} paramagnetic molecular state, providing a significant advantage for the suppression of magnetic field noise and related systematic effects in the eEDM search. In addition, the induced electric dipole moment is shown to be fully saturated in very modest electric fields (<10 V/cm). This feature is favorable for the suppression of many other potential systematic errors in the ThO eEDM search experiment.
6. Measurement of a false electric dipole moment signal from 199Hg atoms exposed to an inhomogeneous magnetic field
NASA Astrophysics Data System (ADS)
Afach, S.; Baker, C. A.; Ban, G.; Bison, G.; Bodek, K.; Chowdhuri, Z.; Daum, M.; Fertl, M.; Franke, B.; Geltenbort, P.; Green, K.; van der Grinten, M. G. D.; Grujic, Z.; Harris, P. G.; Heil, W.; Hélaine, V.; Henneck, R.; Horras, M.; Iaydjiev, P.; Ivanov, S. N.; Kasprzak, M.; Kermaïdic, Y.; Kirch, K.; Knowles, P.; Koch, H.-C.; Komposch, S.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Mtchedlishvili, A.; Naviliat-Cuncic, O.; Pendlebury, J. M.; Piegsa, F. M.; Pignol, G.; Prashant, P. N.; Quéméner, G.; Rebreyend, D.; Ries, D.; Roccia, S.; Schmidt-Wellenburg, P.; Severijns, N.; Weis, A.; Wursten, E.; Wyszynski, G.; Zejma, J.; Zenner, J.; Zsigmond, G.
2015-10-01
We report on the measurement of a Larmor frequency shift proportional to the electric-field strength for 199Hg atoms contained in a volume permeated with aligned magnetic and electric fields. This shift arises from the interplay between the inevitable magnetic field gradients and the motional magnetic field. The proportionality to electric-field strength makes it apparently similar to an electric dipole moment (EDM) signal, although unlike an EDM this effect is P- and T-conserving. We have used a neutron magnetic resonance EDM spectrometer, featuring a mercury co-magnetometer and an array of external cesium magnetometers, to measure the shift as a function of the applied magnetic field gradient. Our results are in good agreement with theoretical expectations.
7. Magnetic dipole transitions in crystals
NASA Astrophysics Data System (ADS)
Wybourne, Brian G.; Smentek, Lidia; Kȩdziorski, Andrzej
2004-01-01
The magnetic dipole transitions in rare earth ions in crystals are described in terms of a model based on the fourth order perturbation theory. An analysis of the perturbing influence of crystal field potential and spin-orbit interaction is made. In addition to intra-shell interactions, inter-shell interactions that include the influence of the excited configurations are analysed. The transition amplitude is defined in terms of effective operators expressed by double unit tensor operators. The radial integrals of all effective operators are defined within the perturbed function approach, therefore the complete radial basis sets of one-electron states of given symmetry are taken into account. Conclusions mainly focus on the possible importance of magnetic dipole transitions in the description of electric dipole 0 ↔ 0 transition due to the so-called borrowing mechanism.
8. Lithium electric dipole polarizability
SciTech Connect
Puchalski, M.; KePdziera, D.; Pachucki, K.
2011-11-15
The electric dipole polarizability of the lithium atom in the ground state is calculated including relativistic and quantum electrodynamics corrections. The obtained result {alpha}{sub E}=164.0740(5) a.u. is in good agreement with the less accurate experimental value of 164.19(1.08) a.u. The small uncertainty of about 3 parts per 10{sup 6} comes from the approximate treatment of quantum electrodynamics corrections. Our theoretical result can be considered as a benchmark for more general atomic structure methods and may serve as a reference value for the relative measurement of polarizabilities of the other alkali-metal atoms.
9. How to Introduce the Magnetic Dipole Moment
ERIC Educational Resources Information Center
Bezerra, M.; Kort-Kamp, W. J. M.; Cougo-Pinto, M. V.; Farina, C.
2012-01-01
We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the…
10. How to Introduce the Magnetic Dipole Moment
ERIC Educational Resources Information Center
Bezerra, M.; Kort-Kamp, W. J. M.; Cougo-Pinto, M. V.; Farina, C.
2012-01-01
We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the
11. Magnetic dipole transitions in the hydrogen molecule
SciTech Connect
Pachucki, Krzysztof; Komasa, Jacek
2011-03-15
In homonuclear molecules, such as H{sub 2}, the electric dipole transitions are strongly forbidden, and the transitions between rovibrational states are of the electric quadrupole type. We show, however, that magnetic dipole transitions also take place, although they are significantly weaker. We evaluate the probabilities of such transitions between several of the lowest rotational states and compare them with those of the corresponding electric quadrupole transitions.
12. Axion induced oscillating electric dipole moments
SciTech Connect
Hill, Christopher T.
2015-06-24
In this study, the axion electromagnetic anomaly induces an oscillating electric dipole for any magnetic dipole. This is a low energy theorem which is a consequence of the space-time dependent cosmic background field of the axion. The electron will acquire an oscillating electric dipole of frequency ma and strength ~ 10-32 e-cm, within four orders of magnitude of the present standard model DC limit, and two orders of magnitude above the nucleon, assuming standard axion model and dark matter parameters. This may suggest sensitive new experimental venues for the axion dark matter search.
13. Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute
NASA Astrophysics Data System (ADS)
Afach, S.; Bison, G.; Bodek, K.; Burri, F.; Chowdhuri, Z.; Daum, M.; Fertl, M.; Franke, B.; Grujic, Z.; Hélaine, V.; Henneck, R.; Kasprzak, M.; Kirch, K.; Koch, H.-C.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Meier, M.; Naviliat-Cuncic, O.; Piegsa, F. M.; Pignol, G.; Plonka-Spehr, C.; Prashanth, P. N.; Quéméner, G.; Rebreyend, D.; Roccia, S.; Schmidt-Wellenburg, P.; Schnabel, A.; Severijns, N.; Voigt, J.; Weis, A.; Wyszynski, G.; Zejma, J.; Zenner, J.; Zsigmond, G.
2014-08-01
The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5 m × 2.5 m × 3 m, disturbances of the magnetic field are attenuated by factors of 5-50 at a bandwidth from 10 - 3 Hz up to 0.5 Hz, which corresponds to integration times longer than several hundreds of seconds and represent the important timescale for the neutron electric dipole moment measurement. These shielding factors apply to random environmental noise from arbitrary sources. This is achieved via a proportional-integral feedback stabilization system that includes a regularized pseudoinverse matrix of proportionality factors which correlates magnetic field changes at all sensor positions to current changes in the SFC coils.
14. Dynamic stabilization of the magnetic field surrounding the neutron electric dipole moment spectrometer at the Paul Scherrer Institute
SciTech Connect
Afach, S.; Fertl, M.; Franke, B. E-mail: [email protected]; Kirch, K.; Bison, G.; Burri, F.; Chowdhuri, Z.; Daum, M.; Henneck, R.; Lauss, B. E-mail: [email protected]; Meier, M.; Schmidt-Wellenburg, P.; Zsigmond, G.; Bodek, K.; Zejma, J.; Grujic, Z.; Kasprzak, M.; Weis, A.; Hélaine, V.; Koch, H.-C.; and others
2014-08-28
The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5 m × 2.5 m × 3 m, disturbances of the magnetic field are attenuated by factors of 5–50 at a bandwidth from 10{sup −3} Hz up to 0.5 Hz, which corresponds to integration times longer than several hundreds of seconds and represent the important timescale for the neutron electric dipole moment measurement. These shielding factors apply to random environmental noise from arbitrary sources. This is achieved via a proportional-integral feedback stabilization system that includes a regularized pseudoinverse matrix of proportionality factors which correlates magnetic field changes at all sensor positions to current changes in the SFC coils.
15. Role of electric and magnetic dipole strength functions in the 114Cd(? ,?' ) and 113Cd(n ,? ) reactions
NASA Astrophysics Data System (ADS)
Massarczyk, R.; Schramm, G.; Belgya, T.; Schwengner, R.; Beyer, R.; Bemmerer, D.; Elekes, Z.; Grosse, E.; Hannaske, R.; Junghans, A. R.; Kis, Z.; Kgler, T.; Lorenz, C.; Schmidt, K.; Szentmiklsi, L.; Wagner, A.; Weil, J. L.
2016-01-01
The distribution of the electromagnetic dipole strength below the neutron separation energy and its influence on the photon distribution after neutron capture were investigated in two experiments for the compound nucleus 114Cd. By measuring the photoabsorption cross section at the bremsstrahlung facility ? ELBE at Helmholtz-Zentrum Dresden-Rossendorf it was possible to deduce the distribution of dipole strength below the neutron separation energy. The de-excitation spectrum after cold-neutron capture in 113Cd was measured at the Budapest Neutron Center. In a combined analysis, the experimentally deduced spectra after photon scattering on 114Cd and the neutron capture in 113Cd were analyzed in terms of electric and magnetic strength functions and nuclear level density with the help of the statistical code ? dex.
16. Far-zone fields of electric and magnetic dipoles in a stratified laterally isotropic earth and mitigating the airwave in marine CSEM
NASA Astrophysics Data System (ADS)
Singer, B. Sh.
2015-06-01
Asymptotic expressions are derived for electromagnetic fields induced by arbitrarily oriented electric and magnetic dipoles in a laterally isotropic stratified medium. Considering that the leading terms, which describe the airwave, decay in accordance with the same geometric law whether the source is a horizontal electric or magnetic dipole, it is suggested to use a transmitter, which combines these sources. It is shown that the airwave greatly diminishes if the amplitudes and phases of the horizontal current and magnetic moments of this transmitter are chosen to minimize the far-zone vertical magnetic field. A properly tuned combined transmitter will induce the electromagnetic field with a relatively small transverse electric mode. Raw electromagnetic data acquired with the combined transmitter will be more sensitive to parameters of the resistive reservoir than data acquired using the traditional horizontal electric dipole type of the transmitter.
17. Magnetization-induced local electric dipoles and multiferroic properties of Ba2CoGe2O7
NASA Astrophysics Data System (ADS)
Solovyev, I. V.
2015-06-01
Ba2CoGe2O7 , crystallizing in the noncentrosymmetric but nonpolar P 4 ¯21m structure, belongs to a special class of multiferroic materials, whose properties are featured by the presence of rotoinversion symmetry. Unlike inversion, the rotoinversion symmetry can be easily destroyed by magnetization. Moreover, due to the specific structural pattern, in which magnetic Co2 + ions are separated by nonmagnetic GeO4 tetrahedra, the magnetic structure of Ba2CoGe2O7 is relatively soft. Altogether, this leads to a rich variety of multiferroic properties, where the magnetic structure of Ba2CoGe2O7 can be easily deformed by the magnetic field, inducing the net electric polarization in the direction depending on the magnetic symmetry of the system, which itself depends on the direction of the magnetic field. In this paper, we show that all these properties can be successfully explained on the basis of a realistic low-energy model, derived from first-principles electronic structure calculations for the magnetically active Co 3 d bands, and the Berry-phase theory of electronic polarization. Particularly, we argue that the magnetization-induced electric polarization in Ba2CoGe2O7 is essentially local and can be expressed via the expectation values
=Tr [p ̂D ̂] of some dipole matrices p ̂ and the site-diagonal density matrices D ̂ of the magnetic Co atoms. Thus, the basic aspects of multiferroic properties of Ba2CoGe2O7 can be understood already in the atomic limit, where both magnetic anisotropy and magnetoelectric coupling are specified by D ̂. Then, the observable polarization is the macroscopic average over the microscopic electric dipoles
. We discuss the behavior of interatomic magnetic interactions, the main contributions to the magnetocrystalline anisotropy, and the spin canting in the x y plane, as well as the similarities and differences between the proposed picture and the phenomenological model of spin-dependent p -d hybridization.
18. electric dipole superconductor in bilayer exciton system
NASA Astrophysics Data System (ADS)
Sun, Qing-Feng; Jiang, Qing-Dong; Bao, Zhi-Qiang; Xie, X. C.
Recently, it was reported that the bilayer exciton systems could exhibit many new phenomena, including the large bilayer counterflow conductivity, the Coulomb drag, etc. These phenomena imply the formation of exciton condensate superfluid state. On the other hand, it is now well known that the superconductor is the condensate superfluid state of the Cooper pairs, which can be viewed as electric monopoles. In other words, the superconductor state is the electric monopole condensate superfluid state. Thus, one may wonder whether there exists electric dipole superfluid state. In this talk, we point out that the exciton in a bilayer system can be considered as a charge neutral electric dipole. And we derive the London-type and Ginzburg-Landau-type equations of electric dipole superconductivity. From these equations, we discover the Meissner-type effect (against spatial variation of magnetic fields), and the dipole current Josephson effect. The frequency in the AC Josephson effect of the dipole current is equal to that in the normal (monopole) superconductor. These results can provide direct evidence for the formation of exciton superfluid state in the bilayer systems and pave new ways to obtain the electric dipole current. We gratefully acknowledge the financial support by NBRP of China (2012CB921303 and 2015CB921102) and NSF-China under Grants Nos. 11274364 and 11574007.
19. CrRb: A molecule with large magnetic and electric dipole moments
SciTech Connect
Pavlovic, Z.; Sadeghpour, H. R.; Cote, R.; Roos, B. O.
2010-05-15
We report calculations of Born-Oppenheimer potential energy curves of the chromium-rubidium heteronuclear molecule ({sup 52}Cr{sup 87}Rb), and the long-range dispersion coefficient for the interaction between ground state Cr and Rb atoms. Our calculated van der Waals coefficient (C{sub 6}=1770 a.u.) has an expected error of 3%. The ground state {sup 6{Sigma}+} molecule at its equilibrium separation has a permanent electric dipole moment of d{sub e}(R{sub e}=3.34Angstrom)=2.90 D. We investigate the hyperfine and dipolar collisions between trapped Cr and Rb atoms, finding elastic to inelastic cross section ratio of 10{sup 2}-10{sup 3}.
20. Vlf/elf radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetoplasma.
NASA Technical Reports Server (NTRS)
Wang, T. N. C.; Bell, T. F.
1972-01-01
With the use of a power integral formulation, a study is made of the vlf/elf radiation patterns of arbitrarily oriented electric and magnetic dipoles in a cold lossless multicomponent magnetoplasma. Expressions for the ray patterns are initially developed that apply for arbitrary values of driving frequency, static magnetic-field strength, plasma density, and composition. These expressions are subsequently specialized to vlf/elf radiation in a plasma modeled on the magnetosphere. A series of representative pattern plots are presented for frequencies between the proton and electron gyrofrequencies. These patterns illustrate the fact that focusing effects that arise from the geometrical properties of the refractive index surface tend to dominate the radiation distribution over the entire range from the electron gyrofrequency to 4.6 times the proton gyrofrequency. It is concluded that focusing effects should be of significant importance in the design of a vlf/elf satellite transmitting system in the magnetosphere.
1. About a peculiar extra U(1): Z{sup '} discovery limit, muon anomalous magnetic moment, and electron electric dipole moment
SciTech Connect
Heo, Jae Ho
2009-08-01
The model (Lagrangian) with a peculiar extra U(1)[S. M. Barr and I. Dorsner, Phys. Rev. D 72, 015011 (2005); S. M. Barr and A. Khan, Phys. Rev. D 74, 085023 (2006)] is clearly presented. The assigned extra U(1) gauge charges give a strong constraint to build Lagrangians. The Z{sup '} discovery limits are estimated and predicted at the Tevatron and the LHC. The new contributions of the muon anomalous magnetic moment are investigated at one and two loops, and we predict that the deviation from the standard model may be explained. The electron electric dipole moment could also be generated because of the explicit CP-violation effect in the Higgs sector, and a sizable contribution is expected for a moderately sized CP phase [argument of the CP-odd Higgs], 0.1{<=}sin{delta}{<=}1[6 deg. {<=}arg(A){<=}90 deg.].
2. Excitation of magnetic dipole transitions at optical frequencies.
PubMed
Kasperczyk, Mark; Person, Steven; Ananias, Duarte; Carlos, Luis D; Novotny, Lukas
2015-04-24
We use the magnetic field distribution of an azimuthally polarized focused laser beam to excite a magnetic dipole transition in Eu^{3+} ions embedded in a Y2O3 nanoparticle. The absence of the electric field at the focus of an azimuthally polarized beam allows us to unambiguously demonstrate that the nanoparticle is excited by the magnetic dipole transition near 527.5 nm. When the laser wavelength is resonant with the magnetic dipole transition, the nanoparticle maps the local magnetic field distribution, whereas when the laser wavelength is resonant with an electric dipole transition, the nanoparticle is sensitive to the local electric field. Hence, by tuning the excitation wavelength, we can selectively excite magnetic or electric dipole transitions through optical fields. PMID:25955052
3. Dipole relaxation in an electric field
NASA Astrophysics Data System (ADS)
Neumann, Richard M.
1980-07-01
From Boltzmann's equation, S=k lnΩ, an expression for the orientational entropy, S of a rigid rod (electric dipole) is derived. The free energy of the dipole in an electric field is then calculated as a function of both the dipole's average orientation and the field strength. Application of the equilibrium criterion to the free energy yields the field dependence of the entropy of the dipole. Irreversible thermodynamics is used to derive the general form of the equation of motion of the dipole's average orientation. Subsequent application of Newton's second law of motion produces Debye's classical expression for the relaxation of an electric dipole in a viscous medium.
4. Classical states of an electric dipole in an external magnetic field: Complete solution for the center of mass and trapped states
SciTech Connect
Atenas, Boris; Pino, Luis A. del; Curilef, Sergio
2014-11-15
We study the classical behavior of an electric dipole in the presence of a uniform magnetic field. Using the Lagrangian formulation, we obtain the equations of motion, whose solutions are represented in terms of Jacobi functions. We also identify two constants of motion, namely, the energy E and a pseudomomentumC{sup →}. We obtain a relation between the constants that allows us to suggest the existence of a type of bound states without turning points, which are called trapped states. These results are consistent with and complementary to previous results. - Highlights: • Bound states without turning points. • Lagrangian Formulation for an electric dipole in a magnetic field. • Motion of the center of mass and trapped states. • Constants of motion: pseudomomentum and energy.
5. Measuring the Forces between Magnetic Dipoles
ERIC Educational Resources Information Center
Gayetsky, Lisa E.; Caylor, Craig L.
2007-01-01
We describe a simple undergraduate lab in which students determine how the force between two magnetic dipoles depends on their separation. We consider the case where both dipoles are permanent and the case where one of the dipoles is induced by the field of the other (permanent) dipole. Agreement with theoretically expected results is quite good.
6. Magnetic field modification of optical magnetic dipoles.
PubMed
Armelles, Gaspar; Caballero, Blanca; Cebollada, Alfonso; Garcia-Martin, Antonio; Meneses-Rodríguez, David
2015-03-11
Acting on optical magnetic dipoles opens novel routes to govern light-matter interaction. We demonstrate magnetic field modification of the magnetic dipolar moment characteristic of resonant nanoholes in thin magnetoplasmonic films. This is experimentally shown through the demonstration of the magneto-optical analogue of Babinet's principle, where mirror imaged MO spectral dependencies are obtained for two complementary magnetoplasmonic systems: holes in a perforated metallic layer and a layer of disks on a substrate. PMID:25646869
7. Magnetic Field of a Dipole and the Dipole-Dipole Interaction
ERIC Educational Resources Information Center
Kraftmakher, Yaakov
2007-01-01
With a data-acquisition system and sensors commercially available, it is easy to determine magnetic fields produced by permanent magnets and to study the dipole-dipole interaction for different separations and angular positions of the magnets. For sufficiently large distances, the results confirm the 1/R[superscript 3] law for the magnetic field…
8. Magnetic Field of a Dipole and the Dipole-Dipole Interaction
ERIC Educational Resources Information Center
Kraftmakher, Yaakov
2007-01-01
With a data-acquisition system and sensors commercially available, it is easy to determine magnetic fields produced by permanent magnets and to study the dipole-dipole interaction for different separations and angular positions of the magnets. For sufficiently large distances, the results confirm the 1/R[superscript 3] law for the magnetic field
9. Dipole Relaxation in an Electric Field.
ERIC Educational Resources Information Center
Neumann, Richard M.
1980-01-01
Derives an expression for the orientational entropy of a rigid rod (electric dipole) from Boltzmann's equation. Subsequent application of Newton's second law of motion produces Debye's classical expression for the relaxation of an electric dipole in a viscous medium. (Author/GS)
10. The electric dipole moment of trimethylene sulphone
NASA Astrophysics Data System (ADS)
López, Juan C.; Lister, David G.; Alonso, José L.
1991-02-01
Stark effect measurements in trimethylene sulphone have been analysed to give a value of 0.23 D for the μ b electric dipole transition moment connecting the v=O and v=1 states of the ring-puckering vibration. The μ a component of the electric dipole moment has been determined in the v=0 to v=3 states of this vibration.
11. Electric dipoles on the Bloch sphere
NASA Astrophysics Data System (ADS)
Vutha, Amar C.
2015-03-01
The time evolution of a two-level quantum mechanical system can be geometrically described using the Bloch sphere. By mapping the Bloch sphere evolution onto the dynamics of oscillating electric dipoles, we provide a physically intuitive link between classical electromagnetism and the electric dipole transitions of atomic and molecular physics.
12. Quantitatively analyzing the mechanism of giant circular dichroism in extrinsic plasmonic chiral nanostructures by tracking the interplay of electric and magnetic dipoles
NASA Astrophysics Data System (ADS)
Hu, Li; Tian, Xiaorui; Huang, Yingzhou; Fang, Liang; Fang, Yurui
2016-02-01
Plasmonic chirality has drawn much attention because of tunable circular dichroism (CD) and the enhancement for chiral molecule signals. Although various mechanisms have been proposed to explain the plasmonic CD, a quantitative explanation like the ab initio mechanism for chiral molecules, is still unavailable. In this study, a mechanism similar to the mechanisms associated with chiral molecules was analyzed. The giant extrinsic circular dichroism of a plasmonic splitting rectangle ring was quantitatively investigated from a theoretical standpoint. The interplay of the electric and magnetic modes of the meta-structure is proposed to explain the giant CD. We analyzed the interplay using both an analytical coupled electric-magnetic dipole model and a finite element method model. The surface charge distributions showed that the circular current yielded by the splitting rectangle ring causes the ring to behave like a magneton at some resonant modes, which then interact with the electric modes, resulting in a mixing of the two types of modes. The strong interplay of the two mode types is primarily responsible for the giant CD. The analysis of the chiral near-field of the structure shows potential applications for chiral molecule sensing.Plasmonic chirality has drawn much attention because of tunable circular dichroism (CD) and the enhancement for chiral molecule signals. Although various mechanisms have been proposed to explain the plasmonic CD, a quantitative explanation like the ab initio mechanism for chiral molecules, is still unavailable. In this study, a mechanism similar to the mechanisms associated with chiral molecules was analyzed. The giant extrinsic circular dichroism of a plasmonic splitting rectangle ring was quantitatively investigated from a theoretical standpoint. The interplay of the electric and magnetic modes of the meta-structure is proposed to explain the giant CD. We analyzed the interplay using both an analytical coupled electric-magnetic dipole model and a finite element method model. The surface charge distributions showed that the circular current yielded by the splitting rectangle ring causes the ring to behave like a magneton at some resonant modes, which then interact with the electric modes, resulting in a mixing of the two types of modes. The strong interplay of the two mode types is primarily responsible for the giant CD. The analysis of the chiral near-field of the structure shows potential applications for chiral molecule sensing. Electronic supplementary information (ESI) available: Near-field distributions in the magnetic field of the splitting rectangle ring and the coupled electric and magnetic dipoles methods. See DOI: 10.1039/c5nr08527f
13. Magnetic dipole discharges. III. Instabilities
SciTech Connect
Stenzel, R. L.; Urrutia, J. M.; Ionita, C.; Schrittwieser, R.
2013-08-15
Instabilities in a cross-field discharge around a permanent magnet have been investigated. The permanent magnet serves as a cold cathode and the chamber wall as an anode. The magnet is biased strongly negative and emits secondary electrons due to impact of energetic ions. The electrons outside the sheath are confined by the strong dipolar magnetic field and by the ion-rich sheath surrounding the magnet. The electron energy peaks in the equatorial plane where most ionization occurs and the ions are trapped in a negative potential well. The discharge mechanism is the same as that of cylindrical and planar magnetrons, but here extended to a 3-D cathode geometry using a single dipole magnet. While the basic properties of the discharge are presented in a companion paper, the present focus is on various observed instabilities. The first is an ion sheath instability which oscillates the plasma potential outside the sheath below the ion plasma frequency. It arises in ion-rich sheaths with low electron supply, which is the case for low secondary emission yields. Sheath oscillations modulate the discharge current creating oscillating magnetic fields. The second instability is current-driven ion sound turbulence due to counter-streaming electrons and ions. The fluctuations have a broad spectrum and short correlation lengths in all directions. The third type of fluctuations is spiky potential and current oscillations in high density discharges. These appear to be due to unstable emission properties of the magnetron cathode.
14. Magnetic dipole oscillations and radiation damping
NASA Astrophysics Data System (ADS)
Stump, Daniel R.; Pollack, Gerald L.
1997-01-01
We consider the problem of radiation damping for a magnetic dipole oscillating in a magnetic field. An equation for the radiation reaction torque is derived, and the damping of the oscillations is described. Also discussed are runaway solutions for a rotating magnetic dipole moving under the influence of the reaction torque, with no external torque.
15. Magnetic dipole interactions in crystals
DOE PAGESBeta
Johnston, David
2016-01-13
The influence of magnetic dipole interactions (MDIs) on the magnetic properties of local-moment Heisenberg spin systems is investigated. A general formulation is presented for calculating the eigenvalues λ and eigenvectors μ ˆ of the MDI tensor of the magnetic dipoles in a line (one dimension, 1D), within a circle (2D) or a sphere (3D) of radius r surrounding a given moment μ → i for given magnetic propagation vectors k for collinear and coplanar noncollinear magnetic structures on both Bravais and non-Bravais spin lattices. Results are calculated for collinear ordering on 1D chains, 2D square and simple-hexagonal (triangular) Bravais lattices,more » 2D honeycomb and kagomé non-Bravais lattices, and 3D cubic Bravais lattices. The λ and μ ˆ values are compared with previously reported results. Calculations for collinear ordering on 3D simple tetragonal, body-centered tetragonal, and stacked triangular and honeycomb lattices are presented for c/a ratios from 0.5 to 3 in both graphical and tabular form to facilitate comparison of experimentally determined easy axes of ordering on these Bravais lattices with the predictions for MDIs. Comparisons with the easy axes measured for several illustrative collinear antiferromagnets (AFMs) are given. The calculations are extended to the cycloidal noncollinear 120 ° AFM ordering on the triangular lattice where λ is found to be the same as for collinear AFM ordering with the same k. The angular orientation of the ordered moments in the noncollinear coplanar AFM structure of GdB 4 with a distorted stacked 3D Shastry-Sutherland spin-lattice geometry is calculated and found to be in disagreement with experimental observations, indicating the presence of another source of anisotropy. Similar calculations for the undistorted 2D and stacked 3D Shastry-Sutherland lattices are reported. The thermodynamics of dipolar magnets are calculated using the Weiss molecular field theory for quantum spins, including the magnetic transition temperature T m and the ordered moment, magnetic heat capacity, and anisotropic magnetic susceptibility χ versus temperature T . The anisotropic Weiss temperature θ p in the Curie-Weiss law for T>T m is calculated. A quantitative study of the competition between FM and AFM ordering on cubic Bravais lattices versus the demagnetization factor in the absence of FM domain effects is presented. The contributions of Heisenberg exchange interactions and of the MDIs to T m and to θ p are found to be additive, which simplifies analysis of experimental data. Some properties in the magnetically-ordered state versus T are presented, including the ordered moment and magnetic heat capacity and, for AFMs, the dipolar anisotropy of the free energy and the perpendicular critical field. The anisotropic χ for dipolar AFMs is calculated both above and below the Néel temperature T N and the results are illustrated for a simple tetragonal lattice with c/a>1, c/a=1 (cubic), and c/a<1 , where a change in sign of the χ anisotropy is found at c/a=1 . Finally, following the early work of Keffer [Phys. Rev. 87, 608 (1952)], the dipolar anisotropy of χ above T N =69 K of the prototype collinear Heisenberg-exchange-coupled tetragonal compound MnF 2 is calculated and found to be in excellent agreement with experimental single-crystal literature data above 130 K, where the smoothly increasing deviation of the experimental data from the theory on cooling from 130 K to T N is deduced to arise from dynamic short-range collinear c -axis AFM ordering in this temperature range driven by the exchange interactions.« less
16. Magnetic dipole interactions in crystals
NASA Astrophysics Data System (ADS)
Johnston, David C.
2016-01-01
The influence of magnetic dipole interactions (MDIs) on the magnetic properties of local-moment Heisenberg spin systems is investigated. A general formulation is presented for calculating the eigenvalues λ and eigenvectors μ ̂ of the MDI tensor of the magnetic dipoles in a line (one dimension, 1D), within a circle (2D) or a sphere (3D) of radius r surrounding a given moment μ⃗i for given magnetic propagation vectors k for collinear and coplanar noncollinear magnetic structures on both Bravais and non-Bravais spin lattices. Results are calculated for collinear ordering on 1D chains, 2D square and simple-hexagonal (triangular) Bravais lattices, 2D honeycomb and kagomé non-Bravais lattices, and 3D cubic Bravais lattices. The λ and μ ̂ values are compared with previously reported results. Calculations for collinear ordering on 3D simple tetragonal, body-centered tetragonal, and stacked triangular and honeycomb lattices are presented for c /a ratios from 0.5 to 3 in both graphical and tabular form to facilitate comparison of experimentally determined easy axes of ordering on these Bravais lattices with the predictions for MDIs. Comparisons with the easy axes measured for several illustrative collinear antiferromagnets (AFMs) are given. The calculations are extended to the cycloidal noncollinear 120∘ AFM ordering on the triangular lattice where λ is found to be the same as for collinear AFM ordering with the same k. The angular orientation of the ordered moments in the noncollinear coplanar AFM structure of GdB4 with a distorted stacked 3D Shastry-Sutherland spin-lattice geometry is calculated and found to be in disagreement with experimental observations, indicating the presence of another source of anisotropy. Similar calculations for the undistorted 2D and stacked 3D Shastry-Sutherland lattices are reported. The thermodynamics of dipolar magnets are calculated using the Weiss molecular field theory for quantum spins, including the magnetic transition temperature Tm and the ordered moment, magnetic heat capacity, and anisotropic magnetic susceptibility χ versus temperature T . The anisotropic Weiss temperature θp in the Curie-Weiss law for T >Tm is calculated. A quantitative study of the competition between FM and AFM ordering on cubic Bravais lattices versus the demagnetization factor in the absence of FM domain effects is presented. The contributions of Heisenberg exchange interactions and of the MDIs to Tm and to θp are found to be additive, which simplifies analysis of experimental data. Some properties in the magnetically-ordered state versus T are presented, including the ordered moment and magnetic heat capacity and, for AFMs, the dipolar anisotropy of the free energy and the perpendicular critical field. The anisotropic χ for dipolar AFMs is calculated both above and below the Néel temperature TN and the results are illustrated for a simple tetragonal lattice with c /a >1 , c /a =1 (cubic), and c /a <1 , where a change in sign of the χ anisotropy is found at c /a =1 . Finally, following the early work of Keffer [Phys. Rev. 87, 608 (1952), 10.1103/PhysRev.87.608], the dipolar anisotropy of χ above TN=69 K of the prototype collinear Heisenberg-exchange-coupled tetragonal compound MnF2 is calculated and found to be in excellent agreement with experimental single-crystal literature data above 130 K, where the smoothly increasing deviation of the experimental data from the theory on cooling from 130 K to TN is deduced to arise from dynamic short-range collinear c -axis AFM ordering in this temperature range driven by the exchange interactions.
17. Propagation of magnetic dipole radiation through a medium.
PubMed
Arnoldus, Henk F; Xu, Zhangjin
2016-05-01
An oscillating magnetic dipole moment emits radiation. We assume that the dipole is embedded in a medium with relative permittivity ϵr and relative permeability μr, and we have studied the effects of the surrounding material on the flow lines of the emitted energy. For a linear dipole moment in free space the flow lines of energy are straight lines, coming out of the dipole. When located in a medium, these field lines curve toward the dipole axis, due to the imaginary part of μr. Some field lines end on the dipole axis, giving a nonradiating contribution to the energy flow. For a rotating dipole moment in free space, each field line of energy flow lies on a cone around the axis perpendicular to the plane of rotation of the dipole moment. The field line pattern is an optical vortex. When embedded in a material, the cone shape of the vortex becomes a funnel shape, and the windings are much less dense than for the pattern in free space. This is again due to the imaginary part of μr. When the real part of μr is negative, the field lines of the vortex swirl around the dipole axis opposite to the rotation direction of the dipole moment. For a near-single-negative medium, the spatial extent of the vortex becomes huge. We compare the results for the magnetic dipole to the case of an embedded electric dipole. PMID:27140885
18. A Spacecraft Magnetic Dipole Moment Determination Method
NASA Astrophysics Data System (ADS)
Strobino, Marco A.
2002-01-01
To learn about the magnitude of the magnetic dipole moment of a spacecraft that will orbit under the influence of the Earth magnetic field, is fundamental in terms of predicting the disturbances that will eventually arise from this interaction with the Earth magnetic field due to magnetic forces. Keeping the total residual magnetic dipole moment at tolerable value is of paramount importance to minimize the control subsystem activity regarding the spacecraft attitude correction, as far as this influence is concerned. This paper presents a method for determining the magnetic dipole moment of a spacecraft or a subsystem of it. The magnetic flux density near field measurements are taken in the presence of the Earth magnetic field, in an environment where the induced magnetic field is a significant component of the total measured magnetic field. Once the dipole moment is determined, the result makes it possible to perform the magnetic balance of the satellite. The compensation is implemented by fixing permanent magnets on the spacecraft, with known magnetic moment magnitudes and in opposite directions, with respect to the determined ones, in any of the 3 axis. The method consists in mapping the 3 axis magnetic flux density field around the vertical axis of the spacecraft by monitoring the magnetic field through several fixed probes located in the horizontal equatorial plane. The magnetic field induced on the satellite by the geomagnetic field at the x and y axis are extracted by comparing the flux density at opposite positions of the device under test. The residual magnetic field mapping is promptly obtained at these 2 axis. Regarding the z-axis, one can determine the composition of the residual and magnetic moment induced by the Earth. One can estimate the residual component by considering the homogeneous morphology of the material used to build the spacecraft. The total induced magnetic field would however be in the same orientation as the Earth magnetic field in the test site. Taking this fact into account, allows us to extract with reasonable precision the z-axis induced magnetic field and the residual magnetic dipole component. In order to achieve the goal of performing the magnetic dipole moment determination and compensation, we had to specify a suitable magnetic measuring system composed of 3-axis fluxgate magnetometers with proper resolution and data acquisition to meet our needs. A numerical procedure based on spherical harmonics analysis was implemented in a specific software developed to process the data and evaluate the magnetic dipole moment. This methodology was applied on CBERS satellite, a 2 meters cube structured three-axis stabilized spacecraft, demonstrating its applicability.
19. Quantitatively analyzing the mechanism of giant circular dichroism in extrinsic plasmonic chiral nanostructures by tracking the interplay of electric and magnetic dipoles.
PubMed
Hu, Li; Tian, Xiaorui; Huang, Yingzhou; Fang, Liang; Fang, Yurui
2016-02-14
Plasmonic chirality has drawn much attention because of tunable circular dichroism (CD) and the enhancement for chiral molecule signals. Although various mechanisms have been proposed to explain the plasmonic CD, a quantitative explanation like the ab initio mechanism for chiral molecules, is still unavailable. In this study, a mechanism similar to the mechanisms associated with chiral molecules was analyzed. The giant extrinsic circular dichroism of a plasmonic splitting rectangle ring was quantitatively investigated from a theoretical standpoint. The interplay of the electric and magnetic modes of the meta-structure is proposed to explain the giant CD. We analyzed the interplay using both an analytical coupled electric-magnetic dipole model and a finite element method model. The surface charge distributions showed that the circular current yielded by the splitting rectangle ring causes the ring to behave like a magneton at some resonant modes, which then interact with the electric modes, resulting in a mixing of the two types of modes. The strong interplay of the two mode types is primarily responsible for the giant CD. The analysis of the chiral near-field of the structure shows potential applications for chiral molecule sensing. PMID:26814829
20. Microstrip dipoles on electrically thick substrates
NASA Astrophysics Data System (ADS)
Jackson, D. R.; Alexopoulos, N. G.
1986-01-01
Certain basic radiation properties of microstrip dipoles on electrically thick substrates are investigated, and a comparison is made with the case of dipoles printed on a dielectric half-space. It is concluded that the microstrip dipole radiation properties become sensitive to substrate loss as the substrate thickness increases, with the half-space properties obtained for an adequate amount of loss. Asymptotic formulas for radiated power and efficiency are given for both the thick substrate and half-space problems, showing the behavior with increasing dielectric constant. The method of moments is used to extend the analysis to center-fed strip dipoles, and a method of improving both the efficiency and gain of a printed antenna by using a superstrate layer is discussed.
1. Magnetic dipole moments for composite dark matter
NASA Astrophysics Data System (ADS)
Aranda, Alfredo; Barajas, Luis; Cembranos, Jose A. R.
2016-03-01
We study neutral dark matter candidates with a nonzero magnetic dipole moment. We assume that they are composite states of new fermions related to the strong phase of a new gauge interaction. In particular, invoking a dark flavor symmetry, we analyze the composition structure of viable candidates depending on the assignations of hypercharge and the multiplets associated to the fundamental constituents of the extended sector. We determine the magnetic dipole moments for the neutral composite states in terms of their constituents masses.
2. Electric dipole moment oscillations in Aharonov-Bohm quantum rings
NASA Astrophysics Data System (ADS)
Alexeev, A. M.; Portnoi, M. E.
2012-06-01
Magneto-oscillations of the electric dipole moment are predicted and analyzed for a single-electron nanoscale ring pierced by a magnetic flux (an Aharonov-Bohm ring) and subjected to an electric field in the ring's plane. These oscillations are accompanied by periodic changes in the selection rules for interlevel optical transitions in the ring allowing control of polarization properties of the associated terahertz radiation.
3. Interaction between two magnetic dipoles in a uniform magnetic field
NASA Astrophysics Data System (ADS)
Ku, J. G.; Liu, X. Y.; Chen, H. H.; Deng, R. D.; Yan, Q. X.
2016-02-01
A new formula for the interaction force between two magnetic dipoles in a uniform magnetic field is derived taking their mutual magnetic interaction into consideration and used to simulate their relative motion. Results show that when the angle β between the direction of external magnetic field and the centerline of two magnetic dipoles is 0 ° or 90 °, magnetic dipoles approach each other or move away from each other in a straight line, respectively. And the time required for them to contact each other from the initial position is related to the specific susceptibility and the diameter of magnetic particles, medium viscosity and magnetic field strength. When β is between 0 ° and 90 °, magnetic dipole pair performs approximate elliptical motion, and the motion trajectory is affected by the specific susceptibility, diameter and medium viscosity but not magnetic field strength. However, time required for magnetic dipoles to complete the same motion trajectory is shorter when adopting stronger magnetic field. Moreover, the subsequent motion trajectory of magnetic dipoles is ascertained once the initial position is set in a predetermined motion trajectory. Additionally, magnetic potential energy of magnetic dipole pairs is transformed into kinetic energy and friction energy during the motion.
4. Quantum electric-dipole liquid on a triangular lattice
PubMed Central
Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F.; Sun, Young
2016-01-01
Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics. PMID:26843363
5. Quantum electric-dipole liquid on a triangular lattice.
PubMed
Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F; Sun, Young
2016-01-01
Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics. PMID:26843363
6. Microstrip dipole antennas on electrically thick substrates
NASA Astrophysics Data System (ADS)
Jackson, D. R.; Alexopoulos, N. G.
1985-10-01
Printed circuit antennas are attractive radiation sources both at microwave and millimeter wave frequencies. However, for millimeter wave applications where the substrate is likely to be electrically thick, it is important to understand the basic effects of a thick substrate on radiation characteristics. In particular, it is concluded here that dipole radiation properties become sensitive to loss as the substrate becomes thick. Furthermore, the efficiency of dipoles on thick substrates tends to be low, especially as the dielectric constant of the substrate increases. A method of improving both the efficiency and gain can be used for thick substrates, however, which uses a superstrate layer on top of the antenna.
7. Neutron electric dipole moment and CP
SciTech Connect
Chang, Darwin; Chang, We-Fu; Frank, Mariana; Keung, Wai-Yee
2000-11-01
We analyze the neutron electric dipole moment (EDM) in the minimal supersymmetric standard model with explicit R-parity violating terms. The leading contribution to the EDM occurs at the two-loop level and is dominated by the chromoelectric dipole moments of quarks, assuming there is no tree-level mixings between sleptons and Higgs bosons or between leptons and gauginos. Based on the experimental constraint on the neutron EDM, we set limits on the imaginary parts of complex couplings {lambda}{sub ijk}{prime} and {lambda}{sub ijk} due to the virtual b loop or {tau} loop.
8. Electric dipole moment of light nuclei
SciTech Connect
Afnan, Iraj R.; Gibson, Benjamin F.
2010-07-27
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
9. Electric dipole moment of light nuclei
SciTech Connect
Gibson, Benjamin; Afnan, I R
2010-01-01
We examine the sensitivity of the deuteron Electric Dipole Moment (EDM) to variation in the nucleon-nucleon interaction. In particular, we write the EDM as a sum of two terms, one depends on the target wave function, the second on intermediate multiple scattering states in the {sup 3}P{sub 1} channel. This second contribution is sensitive to off-shell behavior of the {sup 3}P{sub 1} amplitude.
10. Search for the electron electric dipole moment
SciTech Connect
De Mille, D.; Bickman, S.; Hamilton, P.; Jiang, Y.; Prasad, V.; Kawall, D.; Paolino, R.
2006-07-11
Extensions to the Standard Model (SM) typically include new heavy particles and new mechanisms for CP violation. These underlying phenomena can give rise to electric dipole moments of the electron and other particles. Tabletop-scale experiments used to search for these effects are described. Present experiments are already sensitive to new physics at the TeV scale, and new methods could extend this range dramatically. Such experiments could be among the first to show evidence for physics beyond the SM.
11. Recent developments in neutron electric dipole moment and related CP violating quantities
SciTech Connect
Chang, D. . Dept. of Physics and Astronomy Fermi National Accelerator Lab., Batavia, IL )
1990-12-20
We summarize recent theoretical developments in CP violation related to the neutron electric dipole moment, chromo-electric dipole moments for quarks, chromo-electric dipole moment for gluon, and electric dipole moments for electron and W boson. 31 refs.
12. Conductor Development for High Field Dipole Magnets
SciTech Connect
Scanlan, R.M.; Dietderich, D.R.; Higley, H.C.
2000-03-01
Historically, improvements in dipole magnet performance have been paced by improvements in the superconductor available for use in these magnets. The critical conductor performance parameters for dipole magnets include current density, piece length, effective filament size, and cost. Each of these parameters is important for efficient, cost effective dipoles, with critical current density being perhaps the most important. Several promising magnet designs for the next hadron collider or a muon collider require fields of 12 T or higber, i.e. beyond the reach of NbTi. The conductor options include Nb{sub 3}Sn, Nb{sub 3}Al, or the high temperature superconductors. Although these conductors have the potential to provide the combination of performance and cost required, none of them have been developed sufficiently at this point to satisfy all the requirements. This paper will review the status of each class of advanced conductor and discuss the remaining problems that require solutions before these new conductors can be considered as practical. In particular, the plans for a new program to develop Nb{sub 3}Sn and Nb{sub 3}Al conductors for high energy physics applications will be presented. Also, the development of a multikiloamp Bi-2212 cable for dipole magnet applications will be reported.
13. Magnetic dipole moment of vector mesons
SciTech Connect
Castro, G. Lopez; Sanchez, G. Toledo
1999-10-25
We analyze the sensitivity to the vector-meson magnetic dipole moment of radiative processes involving the production and decay of vector mesons. These studies assume that vector mesons are stable particles. We then discuss how to incorporate the finite-width effects in the calculations without spoiling the electromagnetic gauge invariance of the scattering amplitudes.
14. The Case of the Disappearing Magnetic Dipole
ERIC Educational Resources Information Center
Gough, W.
2008-01-01
The problem of an oscillating magnetic dipole at the centre of a lossless dielectric spherical shell is considered. For simplicity, the free-space wavelength is taken to be much greater than the shell radii, but the relative permittivity [epsilon][subscript r] of the shell is taken as much greater than unity, so the wavelength in the shell could…
15. The Case of the Disappearing Magnetic Dipole
ERIC Educational Resources Information Center
Gough, W.
2008-01-01
The problem of an oscillating magnetic dipole at the centre of a lossless dielectric spherical shell is considered. For simplicity, the free-space wavelength is taken to be much greater than the shell radii, but the relative permittivity [epsilon][subscript r] of the shell is taken as much greater than unity, so the wavelength in the shell could
16. Circular current loops, magnetic dipoles and spherical harmonic analysis.
USGS Publications Warehouse
Alldredge, L.R.
1980-01-01
Spherical harmonic analysis (SHA) is the most used method of describing the Earth's magnetic field, even though spherical harmonic coefficients (SHC) almost completely defy interpretation in terms of real sources. Some moderately successful efforts have been made to represent the field in terms of dipoles placed in the core in an effort to have the model come closer to representing real sources. Dipole sources are only a first approximation to the real sources which are thought to be a very complicated network of electrical currents in the core of the Earth. -Author
17. THE SNS RING DIPOLE MAGNETIC FIELD QUALITY.
SciTech Connect
WANDERER,P.; JACKSON,J.; JAIN,A.; LEE,Y.Y.; MENG,W.; PAPAPHILIPPOU,I.; SPATARO,C.; TEPIKIAN,S.; TSOUPAS,N.; WEI,J.
2002-06-03
The large acceptance and compact size of the Spallation Neutron Source (SNS) ring implies the use of short, large aperture dipole magnets, with significant end field errors. The SNS will contain 32 such dipoles. We report magnetic field measurements of the first 16 magnets. The end field errors have been successfully compensated by the use of iron bumps. For 1.0 GeV protons, the magnets have been shimmed to meet the 0.01% specification for rms variation of the integral field. At 1.3 GeV, the rms variation is 0.036%. The load on the corrector system at 1.3 GeV will be reduced by the use of sorting.
18. Electric Dipole Theory of Chemical Synaptic Transmission
PubMed Central
Wei, Ling Y.
1968-01-01
In this paper we propose that chemicals such as acetylcholine are electric dipoles which when oriented and arranged in a large array could produce an electric field strong enough to drive positive ions over the junction barrier of the post-synaptic membrane and thus initiate excitation or produce depolarization. This theory is able to explain a great number of facts such as cleft size, synaptic delay, nonregeneration, subthreshold integration, facilitation with repetition, and the calcium and magnesium effects. It also shows why and how acetylcholine could act as excitatory or inhibitory transmitters under different circumstances. Our conclusion is that the nature of synaptic transmission is essentially electrical, be it mediated by electrical or chemical transmitters. PMID:4296121
19. Progress towards an electron electric dipole moment measurement with laser-cooled atoms
NASA Astrophysics Data System (ADS)
Solmeyer, Neal
This dissertation recounts the progress made towards a measurement of the electron electric dipole moment. The existence of a permanent electric dipole moment of any fundamental particle would imply that both time reversal and parity invariance are violated. If an electric dipole moment were measured within current experimental limits it would be the first direct evidence for physics beyond the standard model. For our measurement we use laser-cooled alkali atoms trapped in a pair of 1D optical lattices. The lattices run through three electric field plates so that the two groups of atoms see opposing electric fields. The measurement chamber is surrounded by a four layer mu-metal magnetic shield. Under electric field quantization, the atoms are prepared in a superposition of magnetic sublevels that is sensitive to the electron electric dipole moment in Ramsey-like spectroscopy. The experiment requires very large electric fields and very small magnetic fields. Engineering a system compatible with both of these goals simultaneously is not trivial. Searches for electric dipole moments using neutral atoms in optical lattices have much longer possible interaction times and potentially give more precise information about the inherent symmetry breaking than other methods. This comes at the cost of a higher sensitivity to magnetic fields and possible sources of error associated with the trapping light. If noise and systematic errors can be controlled to our design specifications our experiment will significantly improve the current experimental limit of the electron electric dipole moment.
20. Relativistic unitary coupled-cluster study of the electric quadrupole moment and magnetic dipole hyperfine constants of {sup 199}Hg{sup +}
SciTech Connect
Sur, Chiranjib; Chaudhuri, Rajat K.
2007-09-15
Searching for an accurate optical clock which can serve as a better time standard than the present-day atomic clock is highly demanding from several areas of science and technology. Several attempts have been made to build more accurate clocks with different ion species. In this paper, we discuss the electric quadrupole and hyperfine shifts in the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2}(F=0,m{sub F}=0){r_reversible}5d{sup 10}6s {sup 2}S{sub 1/2}(F=2,m{sub F}=0) clock transition in {sup 199}Hg{sup +}, one of the most promising candidates for next-generation optical clocks. We have applied Fock-space unitary coupled-cluster theory to study the electric quadrupole moment of the 5d{sup 9}6s{sup 2} {sup 2}D{sub 5/2} state and magnetic dipole hyperfine constants of 5d{sup 9}6s{sup 2} {sup 2}D{sub 3/2,5/2} and 5d{sup 10}6s{sup 1} {sup 2}S{sub 1/2} states, respectively, of {sup 199}Hg{sup +}. We have also compared our results with available data. To the best of our knowledge, this is the first time a variant of coupled-cluster theories has been applied to study these kinds of properties of Hg{sup +} and is the most accurate estimate of these quantities to date.
1. Electric dipole moments (EDM) of ionic atoms
NASA Astrophysics Data System (ADS)
Oshima, Sachiko
2010-03-01
Recent investigations show that the second-order perturbation calculations of electric dipole moments (EDM) from the finite nuclear size as well as the relativistic effects are all canceled out by the third-order perturbation effects and that this is due to electron screening. To derive the nucleon EDM from the nucleus, we propose to measure the EDM of an ionic system. In this case, it is shown that the nucleon EDM can survive by the reduction factor of 1/Z for the ionic system with one electron stripped off.
2. Electric dipole moments (EDM) of ionic atoms
SciTech Connect
Oshima, Sachiko
2010-03-15
Recent investigations show that the second-order perturbation calculations of electric dipole moments (EDM) from the finite nuclear size as well as the relativistic effects are all canceled out by the third-order perturbation effects and that this is due to electron screening. To derive the nucleon EDM from the nucleus, we propose to measure the EDM of an ionic system. In this case, it is shown that the nucleon EDM can survive by the reduction factor of 1/Z for the ionic system with one electron stripped off.
3. Large muon electric dipole moment from flavor?
SciTech Connect
Hiller, Gudrun; Huitu, Katri; Rueppell, Timo; Laamanen, Jari
2010-11-01
We study the prospects and opportunities of a large muon electric dipole moment (EDM) of the order (10{sup -24}-10{sup -22}) ecm. We investigate how natural such a value is within the general minimal supersymmetric extension of the standard model with CP violation from lepton flavor violation in view of the experimental constraints. In models with hybrid gauge-gravity-mediated supersymmetry breaking, a large muon EDM is indicative for the structure of flavor breaking at the Planck scale, and points towards a high messenger scale.
4. THE SUBMILLIMETER AND MILLIMETER EXCESS OF THE SMALL MAGELLANIC CLOUD: MAGNETIC DIPOLE EMISSION FROM MAGNETIC NANOPARTICLES?
SciTech Connect
Draine, B. T.; Hensley, Brandon
2012-09-20
The Small Magellanic Cloud (SMC) has surprisingly strong submillimeter- and millimeter-wavelength emission that is inconsistent with standard dust models, including those with emission from spinning dust. Here, we show that the emission from the SMC may be understood if the interstellar dust mixture includes magnetic nanoparticles, emitting magnetic dipole radiation resulting from thermal fluctuations in the magnetization. The magnetic grains can be metallic iron, magnetite Fe{sub 3}O{sub 4}, or maghemite {gamma}-Fe{sub 2}O{sub 3}. The required mass of iron is consistent with elemental abundance constraints. The magnetic dipole emission is predicted to be polarized orthogonally to the normal electric dipole radiation if the nanoparticles are inclusions in larger grains. We speculate that other low-metallicity galaxies may also have a large fraction of the interstellar Fe in magnetic materials.
5. Neutron electric dipole moment and dressed spin
NASA Astrophysics Data System (ADS)
Chu, Ping-Han
The neutron electric dipole moment (EDM) experiment has played a unique role in examining the violation of fundamental symmetries and understanding the nature of electroweak and strong interaction. A non-zero neutron EDM is one of direct evidence for CP and T violation and has the potential to reveal the origin of CP violation and to explore physics beyond the Standard Model. A new neutron EDM experiment will be built to improve a factor of 100 by using a novel technique of ultra-cold neutrons(UCN) in superfluid 4He at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory (ORNL). In the experiment, 3He in the measurement cell will be used as a neutron spin analyzer and a comagnetometer. The absorption between UCN and 3He atoms will emit scintillation light in the superfluid 4He depending on the angle between nuclear spins of two particles. Consequently, the neutron precession frequency can be derived by the scintillation light amplitude. Furthermore, the 3He precession frequency can be measured by the superconducting quantum interference device (SQUID). A dressed-spin technique will also be applied to measure the small precession frequency change due to a non-zero neutron EDM. The dressed-spin technique is used to modify the effective precession frequencies of neutrons and 3He atoms to make them equal by applying an oscillatory field (dressing field) that is perpendicular to the static magnetic field. The phenomenon of the dressed spin for 3He in a cell should be demonstrated before the proposed neutron EDM experiment. A successful measurement over a broad range of the amplitude and frequency of the dressing field was done at the University of Illinois. The observed effects can be explained by using quantum optics formalism. The formalism is diagonalized to solve the solution and confirms the data. In addition, the application of the dressed-spin technique was investigated. The modulation and the feedback loop technique should be considered with the dressed-spin technique for the measurement of the small EDM effect. The modulation of the dressing field arbitrarily changes the relative precession frequency between UCN and 3He. Through the feedback loop, the effective neutron precession frequency can be measured. The corresponding sensitivity of neutron EDM will be estimated. A future neutron EDM experiment could be improved if the dressed-spin technique can be carefully considered and applied.
6. Revised cross section for RHIC dipole magnets
SciTech Connect
Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J.; Willen, E.
1991-01-01
Using the experience gained in designing and building Relativistic Heavy Ion Collider (RHIC) dipole prototype magnets an improved cross section has been developed. Significant features of this design include the use of only three wedges for field shaping and wedge cross sections which are sectors of an annulus. To aid in the understanding of the actual magnets, one has been sectioned, and detailed mechanical and photographic measurements made of the wire positions. The comparison of these measurements with the magnetic field measurements will is presented. 2 refs, 3 figs., 2 tabs.
7. MUON G-2 AND ELECTRIC DIPOLE MOMENTS IN STORAGE RINGS: POWERFUL PROBES OF PHYSICS BEYOND THE STANDARD MODEL.
SciTech Connect
SEMERTZIDIS, Y.K.
2005-05-23
We have shown that the study of dipole moments, both magnetic and electric, in storage rings offer unique opportunities in probing physics beyond the Standard Model (SM). Both methods use similar techniques (particle and spin precession in magnetic storage rings). We are currently investigating the systematic errors associated with the resonance electric dipole moment (EDM) method. So far it looks very promising.
8. Generation of squeezing: magnetic dipoles on cantilevers
NASA Astrophysics Data System (ADS)
Seok, Hyojun; Singh, Swati; Steinke, Steven; Meystre, Pierre
2011-05-01
We investigate the generation of motional squeezed states in a nano-mechanical cantilever. Our model system consists of a nanoscale cantilever - whose center-of-mass motion is initially cooled to its quantum mechanical ground state - magnetically coupled a classically driven mechanical tuning fork. We show that the magnetic dipole-dipole interaction can produce significant phonon squeezing of the center-of-mass motion of the cantilever, and evaluate the effect of various dissipation channels, including the coupling of the cantilever to a heat bath and phase and amplitude fluctuations in the oscillating field driving the tuning fork. US National Science Foundation, the US Army Research Office, DARPA ORCHID program through a grant from AFOSR.
9. Magnetic field decay in model SSC dipoles
SciTech Connect
Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I.; Scanlan, R.M.
1988-08-01
We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs.
10. Electron electric-dipole-moment experiment using electric-field quantized slow cesium atoms
SciTech Connect
Amini, Jason M.; Munger, Charles T. Jr.; Gould, Harvey
2007-06-15
A proof-of-principle electron electric-dipole-moment (e-EDM) experiment using slow cesium atoms, nulled magnetic fields, and electric-field quantization has been performed. With the ambient magnetic fields seen by the atoms reduced to less than 200 pT, an electric field of 6 MV/m lifts the degeneracy between states of unequal |m{sub F}| and, along with the low ({approx_equal}3 m/s) velocity, suppresses the systematic effect from the motional magnetic field. The low velocity and small residual magnetic field have made it possible to induce transitions between states and to perform state preparation, analysis, and detection in regions free of applied static magnetic and electric fields. This experiment demonstrates techniques that may be used to improve the e-EDM limit by two orders of magnitude, but it is not in itself a sensitive e-EDM search, mostly due to limitations of the laser system.
11. Measurement of electric dipole moments at storage rings
NASA Astrophysics Data System (ADS)
Jörg Pretz JEDI Collaboration
2015-11-01
The electric dipole moment (EDM) is a fundamental property of a particle, like mass, charge and magnetic moment. What makes this property in particular interesting is the fact that a fundamental particle can only acquire an EDM via {P} and {T} violating processes. EDM measurements contribute to the understanding of the matter over anti-matter dominance in the universe, a question closely related to the violation of fundamental symmetries. Up to now measurements of EDMs have concentrated on neutral particles. Charged particle EDMs can be measured at storage ring. Plans at Forschungszentrum Jülich and results of first test measurements at the COoler SYnchrotron COSY will be presented.
12. Pulsar Pair Cascades in a Distorted Magnetic Dipole Field
NASA Technical Reports Server (NTRS)
Harding, Alice K.; Muslimov, Alex G.
2010-01-01
We investigate the effect of a distorted neutron star dipole magnetic field on pulsar pair cascade multiplicity and pair death lines. Using a simple model for a distorted dipole field that produces an offset polar cap (PC), we derive the accelerating electric field above the PC in space-charge-limited flow. We find that even a modest azimuthally asymmetric distortion can significantly increase the accelerating electric field on one side of the PC and, combined with a smaller field line radius of curvature, leads to larger pair multiplicity. The death line for producing pairs by curvature radiation moves downward in the P-P-dot diagram, allowing high pair multiplicities in a larger percentage of the radio pulsar population. These results could have important implications for the radio pulsar population, high energy pulsed emission, and the pulsar contribution to cosmic ray positrons.
13. Electric dipole moments: A global analysis
NASA Astrophysics Data System (ADS)
Chupp, Timothy; Ramsey-Musolf, Michael
2015-03-01
We perform a global analysis of searches for the permanent electric dipole moments (EDMs) of the neutron, neutral atoms, and molecules in terms of six leptonic, semileptonic, and nonleptonic interactions involving photons, electrons, pions, and nucleons. By translating the results into fundamental charge-conjugation-parity symmetry (CP) violating effective interactions through dimension six involving standard model particles, we obtain rough lower bounds on the scale of beyond the standard model CP-violating interactions ranging from 1.5 TeV for the electron EDM to 1300 TeV for the nuclear spin-independent electron-quark interaction. We show that planned future measurements involving systems or combinations of systems with complementary sensitivities to the low-energy parameters may extend the mass reach by an order of magnitude or more.
14. Nuclear electric dipole moment of 3He
SciTech Connect
Stetcu, Ionel; Friar, J L; Hayes, A C; Liu, C P; Navratil, P
2008-01-01
In the no-core shell model (NCSM) framework, we calculate the {sup 3}He electric dipole moment (EDM) generated by parity- and time-reversal violation in the nucleon-nucleon interaction. While the results are somehow sensitive to the interaction model chosen for the strong two- and three-body interactions, we demonstrate the pion-exchange dominance to the EDM of {sup 3}He, if the coupling constants for {pi}, {rho} and {omega}-exchanges are of comparable magnitude, as expected. Finally, our results suggest that a measurement of {sup 3}He EDM would be complementary to the currently planned neutron and deuteron experiments, and would constitute a powerful constraint to the models of the pion P- and T-violating interactions.
15. Search for the Neutron Electric Dipole Moment
SciTech Connect
2010-08-04
Searches for the neutron electric dipole moment (EDM) are motivated by their highly suppressed Standard Model value. The observation of a non-zero signal in the next generation of experiments would point unambiguously to the existence of new physics beyond the Standard Model. Several ongoing efforts worldwide hold the potential for an up to two-orders-of-magnitude improvement beyond the current upper limit on the neutron EDM of 2.9x10{sup -6} e-cm. In this talk, I review the basic measurement principles of neutron EDM searches, then discuss a new experiment to be carried out in the United States at the Spallation Neutron Source with ultracold neutrons and an in-situ '3He''co-magnetometer'.
16. A search for the electric dipole of the electron
SciTech Connect
Abdullah, K.F.
1989-08-01
We report a new upper limit on the electric dipole moment (EDM) of the electron of d{sub e} = 0.1 {plus minus} 3.2 {times} 10{sup {minus}26} e-cm. This precision is one hundred times better than any previously published limit and a factor of two better than that of unofficial reports. Recently there has been a great deal of theoretical interest in the possibility of a non-zero electron EDM. Models such as the left-right-symmetric Standard Model and an off-standard'' model with new heavy neutrinos are constrained by the new limit on d{sub e}. A non-zero electron EDM would violate the time reversal and parity space-time symmetries. T-violation was observed in neutral kaon decay and is still not fully explained by the Standard Model. Our experimental technique involves searching for an energy shift, linear in applied electric field, between the m{sub F} = 1 and m{sub F} = {minus}1 magnetic sublevels of the F=1 hyperfine level of the 6{sup 2}P{sub 1/2} ground state of atomic thallium. If the electron has a non-zero EDM, this thallium state will exhibit an atomic electric dipole moment that is roughly 600 times larger. The energy shift is detected with the technique of magnetic resonance spectroscopy, employing separated oscillating fields, applied to an atomic beam of thallium. In the approach, any relative phase-shift between the m{sub F} = {plus minus}1 components of the F=1 wavefunction acquired by the atom as it travels through an electric field is detected through interference with two separate oscillating magnetic fields located on either side of the electric field. The new level of precision is achieved through several improvements on previous experiments including employment of a vertical apparatus, two opposing atomic beams, and optical pumping for atomic state selection and analysis.
17. Electric dipole moment of the electron and of the neutron
NASA Technical Reports Server (NTRS)
Barr, S. M.; Zee, A.
1990-01-01
It is shown that if Higgs-boson exchange mediates CP violation a significant electric dipole moment for the electron can result. Analogous effects can contribute to the neutron's electric dipole moment at a level competitive with Weinberg's three-gluon operator.
18. Electron electric dipole moment experiment using electric-fieldquantized slow cesium atoms
SciTech Connect
Amini, Jason M.; Munger Jr., Charles T.; Gould, Harvey.
2007-04-05
A proof-of-principle electron electric dipole moment (e-EDM)experiment using slow cesium atoms, nulled magnetic fields, and electricfield quantization has been performed. With the ambient magnetic fieldsseen by the atoms reduced to less than 200 pT, an electric field of 6MV/m lifts the degeneracy between states of unequal lbar mF rbar and,along with the low (approximately 3 m/s) velocity, suppresses thesystematic effect from the motional magnetic field. The low velocity andsmall residual magnetic field have made it possible to induce transitionsbetween states and to perform state preparation, analysis, and detectionin regions free of applied static magnetic and electric fields. Thisexperiment demonstrates techniques that may be used to improve the e-EDMlimit by two orders of magnitude, but it is not in itself a sensitivee-EDM search, mostly due to limitations of the laser system.
19. Magnetic dipole discharges. I. Basic properties
NASA Astrophysics Data System (ADS)
Stenzel, R. L.; Urrutia, J. M.; Teodorescu-Soare, C. T.; Ionita, C.; Schrittwieser, R.
2013-08-01
A simple discharge is described which uses a permanent magnet as a cold cathode and the metallic chamber wall as an anode. The magnet's equator is biased strongly negative, which produces secondary electrons due to the impact of energetic ions. The emitted electrons are highly confined by the strong dipolar magnetic field and the negative potential in the equatorial plane of the magnet. The emitted electrons ionize near the sheath and produce further electrons, which drift across field lines to the anode while the nearly unmagnetized ions are accelerated back to the magnet. A steady state discharge is maintained at neutral pressures above 10-3 mbar. This is the principle of magnetron discharges, which commonly use cylindrical and planar cathodes rather than magnetic dipoles as cathodes. The discharge properties have been investigated in steady state and pulsed mode. Different magnets and geometries have been employed. The role of a background plasma has been investigated. Various types of instabilities have been observed such as sheath oscillations, current-driven turbulence, relaxation instabilities due to ionization, and high frequency oscillations created by sputtering impulses, which are described in more detail in companion papers. The discharge has also been operated in reactive gases and shown to be useful for sputtering applications.
20. Communication: Permanent dipoles contribute to electric polarization in chiral NMR spectra
SciTech Connect
Buckingham, A. David
2014-01-07
Nuclear magnetic resonance spectroscopy is blind to chirality because the spectra of a molecule and its mirror image are identical unless the environment is chiral. However, precessing nuclear magnetic moments in chiral molecules in a strong magnetic field induce an electric polarization through the nuclear magnetic shielding polarizability. This effect is equal and opposite for a molecule and its mirror image but is small and has not yet been observed. It is shown that the permanent electric dipole moment of a chiral molecule is partially oriented through the antisymmetric part of the nuclear magnetic shielding tensor, causing the electric dipole to precess with the nuclear magnetic moment and producing a much larger temperature-dependent electric polarization with better prospects of detection.
1. Classical Magnetic Dipole Moments for the Simulation of Vibrational Circular Dichroism by ab Initio Molecular Dynamics.
PubMed
Thomas, Martin; Kirchner, Barbara
2016-02-01
We present a new approach for calculating vibrational circular dichroism spectra by ab initio molecular dynamics. In the context of molecular dynamics, these spectra are given by the Fourier transform of the cross-correlation function of magnetic dipole moment and electric dipole moment. We obtain the magnetic dipole moment from the electric current density according to the classical definition. The electric current density is computed by solving a partial differential equation derived from the continuity equation and the condition that eddy currents should be absent. In combination with a radical Voronoi tessellation, this yields an individual magnetic dipole moment for each molecule in a bulk phase simulation. Using the chiral alcohol 2-butanol as an example, we show that experimental spectra are reproduced very well. Our approach requires knowing only the electron density in each simulation step, and it is not restricted to any particular electronic structure method. PMID:26771403
2. Concentric Titled Double-Helix Dipole Magnets
SciTech Connect
Rainer Meinke, Ph.D; Carl Goodzeit; Millicent Ball, Ph.D
2003-09-05
The high magnetic fields required for future accelerator magnets can only be achieved with Nb3Sn, other A15 or HTS type conductors, which are brittle and sensitive to mechanical strain. The traditional ''cosine-theta'' dipole configuration has intrinsic drawbacks that make it difficult and expensive to employ such conductors in these designs. Some of these problems involve (1) difficulty in applying enough pre-stress to counteract Lorentz forces without compromising conductor performance; (2) small minimum bend radii of the conductor necessitating the intricate wind-and-react coil fabrication; (3) complex spacers in particular for coil ends and expensive tooling for coil fabrication; (4) typically only 2/3 of the coil aperture can be used with achievable field uniformity.
3. Development of a Francium Electron Electric Dipole Moment Experiment
NASA Astrophysics Data System (ADS)
Munger, Charles T., Jr.; Feinberg, B.; Gould, Harvey; Kalnins, Juris; Nishimura, Hiroshi; Jentschura, Ulrich; Behr, John; Pearson, Matt
2014-09-01
An experiment to discover or rule out a permanent electric dipole moment (EDM) of the electron, at a sensitivity well beyond the present experimental limit, is being developed. The experiment will use 211Fr, obtainable online at TRIUMF at rates of 109/s, in a laser-cooled fountain. The experiment is done in free space and free fall, with an electric field, but no applied magnetic field, between optical state preparation and analysis. The relation between an electron EDM and an EDM of a francium atom has recently been recalculated using field theory alone (Blundell, Griffith & Sapirstein, Phys. Rev. D 86, 025023 [2012]), confirming previous atomic physics calculations and removing any ambiguity in the experimental interpretation.
4. Space propulsion by fusion in a magnetic dipole
SciTech Connect
Teller, E.; Glass, A.J.; Fowler, T.K. ); Hasegawa, A. ); Santarius, J.F. . Fusion Technology Inst.)
1991-07-15
The unique advantages of fusion rocket propulsion systems for distant missions are explored using the magnetic dipole configurations as an example. The dipole is found to have features well suited to space applications. Parameters are presented for a system producing a specific power of kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power performance than nuclear electric fission systems. Possibilities to further increase the specific power toward 10 kW/kg are discussed, as is an approach to implementing the concept through proof-testing on the moon. 20 refs., 14 figs., 2 tabs.
5. Pair Cascades and Deathlines in Offset Magnetic Dipole Fields
NASA Technical Reports Server (NTRS)
Harding, Alice; Muslimov, Alex
2010-01-01
We investigate electron-positron pair cascades in a dipole magnetic field whose axis is offset from the neutron star center. In such a field geometry, the polar cap is displaced from the neutron star symmetry axis and the field line radius of curvature is modified. Using the modified parallel electric field near the polar cap of an offset dipole, we simulate pair cascades to determine the pair deathlines and pair multiplicities as a function of the offset parameter. We find that the pair multiplicity can change dramatically with a modest offset, with a significant increase on one side of the polar cap. Lower pair deathlines allow a larger fraction of the pulsar population, that include old and millisecond pulsars, to produce cascades with high multiplicity.
6. Quantitative analysis on electric dipole energy in Rashba band splitting
NASA Astrophysics Data System (ADS)
Hong, Jisook; Rhim, Jun-Won; Kim, Changyoung; Ryong Park, Seung; Hoon Shim, Ji
2015-09-01
We report on quantitative comparison between the electric dipole energy and the Rashba band splitting in model systems of Bi and Sb triangular monolayers under a perpendicular electric field. We used both first-principles and tight binding calculations on p-orbitals with spin-orbit coupling. First-principles calculation shows Rashba band splitting in both systems. It also shows asymmetric charge distributions in the Rashba split bands which are induced by the orbital angular momentum. We calculated the electric dipole energies from coupling of the asymmetric charge distribution and external electric field, and compared it to the Rashba splitting. Remarkably, the total split energy is found to come mostly from the difference in the electric dipole energy for both Bi and Sb systems. A perturbative approach for long wave length limit starting from tight binding calculation also supports that the Rashba band splitting originates mostly from the electric dipole energy difference in the strong atomic spin-orbit coupling regime.
7. Controlling magnetic dipole transition with magnetic plasmonic structures.
PubMed
Feng, Tianhua; Zhou, Ying; Liu, Dahe; Li, Jensen
2011-06-15
A plasmonic structure with double gold patches is proposed for enhancing the spontaneous emission of a magnetic dipole transition through a magnetic hot area. A Purcell factor of nearly 2000 can be obtained at optical frequencies together with a low sensitivity in spatial and spectral mismatches between the light emitter and the resonance mode. The associated resonance can be tuned from the visible to the IR frequencies, enabling efficient control of forbidden transitions using plasmonic structures. PMID:21686023
8. Nuclear Electric Dipole Moment of ^{3}_He
SciTech Connect
Stetcu, I.; Liu, C.-P.; Friar, J. L.; Hayes, A. C.; Navratil, P.
2008-01-01
A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of ^{3}_He and the expected sensitivity of such a measurement to the underlyng CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {\\pi}-, {\\rho}-, and {\\omega}-exchanges, we find that the pion-exchange contribution dominates. Our results suggest that a measurement of the ^{3}_He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.
9. The search for permanent electric dipole moments
SciTech Connect
Kirch, Klaus
2013-02-13
Permanent electric dipole moments (EDMs) of fundamental systems with spin - particles, nuclei, atoms or molecules violate parity and time reversal invariance. Invoking the CPT theorem, time reversal violation implies CP violation. Although CP-violation is implemented in the standard electro-weak theory, EDM generated this way remain undetectably small. However, this CP-violation also appears to fail explaining the observed baryon asymmetry of our universe. Extensions of the standard theory usually include new sources of CP violation and often predict sizeable EDMs. EDM searches in different systems are complementary and various efforts worldwide are underway and no finite value has been established yet. The prototype of an EDM search is the pursuit of the EDM of the neutron. It has the longest history and at the same time is at the forefront of present research. The talk aims at giving an overview of the field with emphasis on our efforts within an international collaboration at PSI, nedm.web.psi.ch.
10. Nuclear Electric Dipole Moment of 3He
SciTech Connect
Stetcu, I; P.Liu, C; Friar, J L; Hayes, A C; Navratil, P
2008-04-08
A permanent electric dipole moment (EDM) of a physical system would require time-reversal (T) violation, which is equivalent to charge-conjugation-parity (CP) violation by CPT invariance. Experimental programs are currently pushing the limits on EDMs in atoms, nuclei, and the neutron to regimes of fundamental theoretical interest. Nuclear EDMs can be studied at ion storage rings with sensitivities that may be competitive with atomic and neutron measurements. Here we calculate the magnitude of the CP-violating EDM of {sup 3}He and the expected sensitivity of such a measurement to the underlying CP-violating interactions. Assuming that the coupling constants are of comparable magnitude for {pi}-, {rho}-, and {omega}-exchanges, we find that the pion-exchange contribution dominates. Finally, our results suggest that a measurement of the {sup 3}He EDM is complementary to the planned neutron and deuteron experiments, and could provide a powerful constraint for the theoretical models of the pion-nucleon P,T-violating interaction.
11. Electric dipole polarizability and the neutral skin
SciTech Connect
Piechaczek, A.; Nazarewicz, Witold; Reinhard, P.-G.; Agrawal, Bijay K; Colo, Gianluca; Paar, Nils; Roca-Maza, X; Vretenar, Dario
2012-01-01
The recent high-resolution measurement of the electric dipole (E1) polarizability {alpha}{sub D} in {sup 208}Pb [A. Tamii et al. Phys. Rev. Lett. 107 062502 (2011)] provides a unique constraint on the neutron-skin thickness of this nucleus. The neutron-skin thickness r{sub skin} of {sup 208}Pb is a quantity of critical importance for our understanding of a variety of nuclear and astrophysical phenomena. To assess the model dependence of the correlation between {alpha}{sub D} and r{sub skin}, we carry out systematic calculations for {sup 208}Pb, {sup 132}Sn, and {sup 48}Ca based on the nuclear density functional theory using both nonrelativistic and relativistic energy density functionals. Our analysis indicates that whereas individual models exhibit a linear dependence between {alpha}{sub D} and r{sub skin}, this correlation is not universal when one combines predictions from a host of different models. By averaging over these model predictions, we provide estimates with associated systematic errors for r{sub skin} and {alpha}{sub D} for the nuclei under consideration. We conclude that precise measurements of r{sub skin} in both {sup 48}Ca and {sup 208}Pb - combined with the recent measurement of {alpha}{sub D} - should significantly constrain the isovector sector of the nuclear energy density functional.
12. Electric Dipole Moment Experiment Systematic from Electric Field Discharge Current
NASA Astrophysics Data System (ADS)
Feinberg, B.; Gould, Harvey
2014-09-01
A magnetic field, in the direction of the electric field and synchronous with the electric field reversal, will mimic an EDM signal. One might expect a discharge across the electric field plates to produce magnetic fields with only small or vanishing components parallel to the electric field, minimizing its systematic effect. Our experimental model, using simulated discharge currents, found otherwise: the discharge current may be at an angle to the normal, and thus generate a normal magnetic field. Comparison of data from the experimental model with the results from calculations will be presented, along with estimates of the time-averaged normal magnetic field seen by atoms in an electron EDM experiment using a fountain of laser-cooled francium, as a function of discharge current.
13. Axion Induced Oscillating Electric Dipole Moment of the Electron
DOE PAGESBeta
Hill, Christopher T.
2016-01-12
A cosmic axion, via the electromagnetic anomaly, induces an oscillating electric dipole for the electron of frequency ma and strength ~(few) x 10-32 e-cm, two orders of magnitude above the nucleon, and within a few orders of magnitude of the present standard model constant limit. We give a detailed study of this phenomenon via the interaction of the cosmic axion, through the electromagnetic anomaly, with particular emphasis on the decoupling limit of the axion, ∂ta(t) ∝ mα → 0. The analysis is subtle, and we find the general form of the action involves a local contact interaction and a nonlocalmore » contribution, analogous to the “transverse current” in QED, that enforces the decoupling limit. We carefully derive the effective action in the Pauli-Schroedinger non-relativistic formalism, and in Georgi’s heavy quark formalism adapted to the “heavy electron” (me >> ma). We compute the electric dipole radiation emitted by free electrons, magnets and currents, immersed in the cosmic axion field, and discuss experimental configurations that may yield a detectable signal.« less
14. The electric dipole moment of cobalt monoxide, CoO
SciTech Connect
Zhuang, Xiujuan; Steimle, Timothy C.
2014-03-28
A number of low-rotational lines of the E{sup 4}Δ{sub 7/2} ← X{sup 4}Δ{sub 7/2} (1,0) band system of cobalt monoxide, CoO, were recorded field free and in the presence of a static electric field. The magnetic hyperfine parameter, h{sub 7/2}, and the electron quadrupole parameter, eQq{sub 0}, for the E{sup 4}Δ{sub 7/2}(υ = 1) state were optimized from the analysis of the field-free spectrum. The permanent electric dipole moment, μ{sup -vector}{sub el}, for the X{sup 4}Δ{sub 7/2} (υ = 0) and E{sup 4}Δ{sub 7/2} (υ = 1) states were determined to be 4.18 ± 0.05 D and 3.28 ± 0.05 D, respectively, from the analysis of the observed Stark spectra of F′ = 7 ← F″ = 6 branch feature in the Q(7/2) line and the F′ = 8 ← F″ = 7 branch feature in the R(7/2) line. The measured dipole moments of CoO are compared to those from theoretical predictions and the trend across the 3d-metal monoxide series discussed.
15. Axion induced oscillating electric dipole moment of the electron
NASA Astrophysics Data System (ADS)
Hill, Christopher T.
2016-01-01
A cosmic axion, via the electromagnetic anomaly, induces an oscillating electric dipole for the electron of frequency ma and strength ˜(few )×10-32 e -cm , two orders of magnitude above the nucleon, and within a few orders of magnitude of the present standard model constant limit. We give a detailed study of this phenomenon via the interaction of the cosmic axion, through the electromagnetic anomaly, with particular emphasis on the decoupling limit of the axion, ∂ta (t )∝ma→0 . The analysis is subtle, and we find the general form of the action involves a local contact interaction and a nonlocal contribution, analogous to the "transverse current" in QED, that enforces the decoupling limit. We carefully derive the effective action in the Pauli-Schrödinger nonrelativistic formalism, and in Georgi's heavy quark formalism adapted to the "heavy electron" (me≫ma ). We compute the electric dipole radiation emitted by free electrons, magnets and currents, immersed in the cosmic axion field, and discuss experimental configurations that may yield a detectable signal.
16. Search for a Permanent Electric Dipole Moment of 225Ra
NASA Astrophysics Data System (ADS)
Kalita, Mukut Ranjan
The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate the violation of discrete symmetries of Time reversal (T) or combined application of Charge (C) and Parity (P) symmetry violation through the CPT theorem. The diamagnetic 225Ra atom with nuclear spin I=1/2 is a favorable candidate for an EDM search. Experimental sensitivity to its EDM is enhanced due to its high atomic mass and the increased Schiff moment of its octupole deformed nucleus. An experimental setup is developed where laser cooled neutral radium atoms are collected in a magneto-optical trap (MOT). The collected atoms are transported 1 meter with a far off-resonant optical dipole trap (ODT) and then the atoms are transferred to a second standing-wave ODT in an experimental chamber. The atoms are then optically polarized and allowed to Larmor precess in parallel and antiparallel electric and magnetic fields. The difference between the Larmor precession frequency for parallel and antiparallel fields is experimentally determined to measure the EDM. This thesis is about the first measurement of the EDM of the 225Ra atom where an upper limit of |d(225Ra)| < 5.0 x 10-22 e·cm (95% confidence) is reached. Keywords: Permanent EDM, CP violation, laser cooling and trapping, rare isotopes, radium.
17. Axion Induced Oscillating Electric Dipole Moment of the Electron
SciTech Connect
Hill, Christopher T.
2015-07-24
The axion electromagnetic anomaly induces an oscillating electric dipole for the electron of frequency ma and strength ~ 10-32 e-cm, two orders of magnitude above the nucleon, and within four orders of magnitude of the present standard model constant limit. We give a detailed study of this phenomenon via the interaction of the cosmic axion, through the electromagnetic anomaly, with particular emphasis on the decoupling limit of the axion, δta(t) ∝ ma → 0. The general form of the action involves a local contact interaction and a nonlocal contribution that enforces the decoupling limit. We derive the effective action in the Pauli-Schroedinger non-relativistic formalism, and in Georgi’s heavy quark formalism adapted to the “heavy electron” (heavy compared to ma). We compute the electric dipole radiation emitted by stationary electrons, and we discuss a number of experimental configurations that may yield detectable signals. Phased array radiators with N2 unit cell magnetic elements may have advantages over resonant cavities that exploit large Q, since we can design toward N2 >> Q.
18. Distribution of orbital magnetic dipole strength in 156Gd
NASA Astrophysics Data System (ADS)
Bohle, D.; Richter, A.; Berg, U. E. P.; Drexler, J.; Heil, R. D.; Kneissl, U.; Metzger, H.; Stock, R.; Fischer, B.; Hollick, H.; Kollewe, D.
1986-10-01
Results from high resolution inelastic electron scattering and nuclear resonance fluorescence experiments on 156Gd are combined to yield information on the distribution of orbital magnetic dipole strength. The magnetic dipole strength connected with the new M1 mode is closely centered in five Jπ = 1 + states around 3 MeV excitation energy.
19. Helical dipole magnets for polarized protons in RHIC
SciTech Connect
Syphers, M.; Courant, E.; Fischer, W.
1997-07-01
Superconducting helical dipole magnets will be used in the Brookhaven Relativistic Heavy Ion Collider (RHIC) to maintain polarization of proton beams and to perform localized spin rotations at the two major experimental detector regions. Requirements for the helical dipole system are discussed, and magnet prototype work is reported.
20. Steerable reflect-array antenna formed by loaded electric dipoles
NASA Astrophysics Data System (ADS)
Mainwaring, A.; Umnov, A. L.; Shuralev, M. O.; Eltsov, A. U.
2011-02-01
A reflect-array antenna with simple design, low cost, and electronically controlled directivity pattern for centimeter wavelength range is proposed. The antenna is based on a mirror formed by loaded electric dipoles.
1. Summary of dipole field angle measurements on 50mm-aperture SSC Collider Dipole Magnet Protoypes
SciTech Connect
Marks, J.; DiMarco, J.; Kuzminski, J.; Ogitsu, T.; Zheng, H.; Bleadon, M.; Kuchnir, M.; Schmidt, E.E.; Yu, Y. |
1993-05-01
At several stages in the production of the SSC collider dipole magnets and their final installation the magnetic field angle needs to be known. A simple device using a permanent magnet which aligns itself with the magnetic field had been developed at FNAL to survey the direction of the magnetic dipole field with respect to the vertical (as determined by gravity) along the magnet axis. The determination of the dipole field angle was part of the field quality characterization of a series of thirteen full-length 50mm-aperture SSC Collider Dipole Magnet Prototypes which were built for R&D purposes at FNAL. Measurements with the first developed FAP system were performed on a regular basis through several stages of the magnet production process with the intention of fabrication quality control. Part of these included measurements performed before and after cryogenic testing: these data are summarized here. The performance of a second system with an improved probe and data acquisition system was tested on part of the DCA series as well. This paper includes a presentation of time stability, noise and angular resolution data of this second probe. Another alternative instrument to determine the dipole field angle is the mole rotating coil system developed at BNL used mainly to measure the multipole components of the magnetic field. In the case of magnet DCA320, a comparison is made between the field angle as determined by the mole and those determined by both of the FAPS.
2. Limit on the Electron Electric Dipole Moment in Gadolinium-Iron Garnet
SciTech Connect
Heidenreich, B.J.; Elliott, O.T.; Charney, N.D.; Virgien, K.A.; Bridges, A.W.; McKeon, M.A.; Peck, S.K.; Krause, D. Jr.; Gordon, J.E.; Hunter, L.R.; Lamoreaux, S.K.
2005-12-16
A new method for the detection of the electron electric dipole moment (EDM) using a solid is described. The method involves the measurement of a voltage induced across the solid by the alignment of the sample's magnetic dipoles in an applied magnetic field, H. A first application of the method to GdIG has resulted in a limit on the electron EDM of 5x10{sup -24}e cm, which is a factor of 40 below the limit obtained from the only previous solid-state EDM experiment. The result is limited by the imperfect discrimination of an unexpectedly large voltage that is even upon the reversal of the sample magnetization.
3. Theoretical Electric Dipole Moments of SiH, GeH and SnH
NASA Technical Reports Server (NTRS)
Pettersson, Lars G. M.; Langhoff, Stephen R.
1986-01-01
Accurate theoretical dipole moments (mu(sub c) have been computed for the X(exp 2)Pi ground states of Si(-)H(+)(0.118 D), Ge(+)H(-)(0.085 D) and Sn(+)H(-)(0.357 D). The trend down the periodic table is regular and follows that expected from the electronegativities of the group IV atoms. The dipole moment of 1.24 +/- 0.1 D for GeH recently derived by Brown, Evenson and Sears from the relative intensities of electric and magnetic dipole transitions in the 10 microns spectrum of the X(exp 2)Pi state is seriously questioned.
4. Theoretical electric dipole moments of SiH, GeH and SnH
NASA Technical Reports Server (NTRS)
Pettersson, L. G. M.; Langhoff, S. R.
1986-01-01
Accurate theoretical dipole moments have been computed for the X2Pi ground states of Si(-)H(+) (0.118 D), Ge(+)H(-) (0.085 D), and Sn(+)H(-) (0.357 D). The trend down the periodic table is regular and follows that expected from the electronegativities of the group IV atoms. The dipole moment of 1.24 + or - 0.1 D for GeH recently derived by Brown, Evenson and Sears (1985) from the relative intensities of electric and magnetic dipole transitions in the 10-micron spectrum of the X2Pi state is seriously questioned.
5. QED vacuum fluctuations and induced electric dipole moment of the neutron
SciTech Connect
Dominguez, C. A.; Falomir, H.; Ipinza, M.; Loewe, M.; Kohler, S.; Rojas, J. C.
2009-08-01
Quantum fluctuations in the QED vacuum generate nonlinear effects, such as peculiar induced electromagnetic fields. In particular, we show here that an electrically neutral particle, possessing a magnetic dipole moment, develops an induced electric dipole-type moment with unusual angular dependence, when immersed in a quasistatic, constant external electric field. The calculation of this effect is done in the framework of the Euler-Heisenberg effective QED Lagrangian, corresponding to the weak field asymptotic expansion of the effective action to one-loop order. It is argued that the neutron might be a good candidate to probe this signal of nonlinearity in QED.
6. Effects of dipole magnet inhomogeneities on the beam ellipsoid
SciTech Connect
Tsoupas, N.; Colman, J.; Levine, M.; McKenzie-Wilson, R.; Ward, T.; Grand, P.
1986-01-01
The RAYTRACE computer code has been modified to accept magnetic fields measured in the median plane of a dipole magnet. This modification allows one to study the effects of a non-ideal dipole magnet on the beam ellipsoid (as defined by the TRANSPORT code manual). The effects on the beam ellipsoid are due to: field inhomogeneities in the interior region of the dipole, and discrepancies from design conditions of the magnetic field values in the fringe field region. The results of the RAYTRACE code calculations based on experimentally measured fields will be compared with the results derived using both an ideal (no inhomogeneities) dipole with SCOFF boundaries and an ideal dipole with perfect (according to design) fringe fields.
7. Measuring the Electron Electric Dipole Moment Using Ytterbium Fluoride Molecules
NASA Astrophysics Data System (ADS)
Smallman, I. J.; Devlin, J. A.; Kara, D. M.; Hudson, J. J.; Sauer, B. E.; Tarbutt, M. R.; Hinds, E. A.
2013-06-01
It is well known that the existence of an electron electric dipole moment (eEDM) would violate time reversal symmetry. The Standard Model predicts an eEDM less than 10^{-38}e.cm, however many popular extensions predict values in the range 10^{-29}-10^{-24}e.cm. Our experiment currently has the potential to measure eEDMs down to approximately 10^{-29}e.cm, making it a precise probe for T-violation and physics beyond the Standard Model. We measure the eEDM by performing a type of separated oscillating field interferometry on a pulsed beam of YbF. The molecules are prepared such that the molecular spin is oriented perpendicular to an applied strong (10kV/cm) electric field. The spin is then allowed to precess about the electric field axis over a 0.5ms interaction period. We measure this angle of rotation, which is directly proportional to the eEDM. In order to measure the eEDM precisely and without error we use a complex switching technique wherein certain parameters, including the applied electric and magnetic fields, are reversed between individual molecular pulses. I will present our current technique and our most recent world leading result.
8. Reply to "Comment on Axion Induced Oscillating Electric Dipole Moments' "
SciTech Connect
Hill, Christopher T.
2015-10-19
A recent paper of Flambaum, Roberts and Stadnik, [1], claims there is no induced oscillating electric dipole moment (OEDM), eg, for the electron, arising from the oscillating cosmic axion background via the anomaly. This claim is based upon the assumption that electric dipoles always be defined by their coupling to static (constant in time) electric fields. The relevant Feynman diagram, as computed by [1], then becomes a total divergence, and vanishes in momentum space. However, an OEDM does arise from the anomaly, coupled to time dependent electric fields. It shares the decoupling properties with the anomaly. The full action, in an arbitrary gauge, was computed in [2], [3]. It is nonvanishing with a time dependent outgoing photon, and yields physics, eg, electric dipole radiation of an electron immersed in a cosmic axion field.
9. Many particle magnetic dipole-dipole and hydrodynamic interactions in magnetizable stent assisted magnetic drug targeting
NASA Astrophysics Data System (ADS)
Cregg, P. J.; Murphy, Kieran; Mardinoglu, Adil; Prina-Mello, Adriele
2010-08-01
The implant assisted magnetic targeted drug delivery system of Avilés, Ebner and Ritter is considered both experimentally ( in vitro) and theoretically. The results of a 2D mathematical model are compared with 3D experimental results for a magnetizable wire stent. In this experiment a ferromagnetic, coiled wire stent is implanted to aid collection of particles which consist of single domain magnetic nanoparticles (radius ≈10 nm). In order to model the agglomeration of particles known to occur in this system, the magnetic dipole-dipole and hydrodynamic interactions for multiple particles are included. Simulations based on this mathematical model were performed using open source C++ code. Different initial positions are considered and the system performance is assessed in terms of collection efficiency. The results of this model show closer agreement with the measured in vitro experimental results and with the literature. The implications in nanotechnology and nanomedicine are based on the prediction of the particle efficiency, in conjunction with the magnetizable stent, for targeted drug delivery.
10. New measurements of the neutron electric dipole moment with the Petersburg Nuclear Physics Institute double-chamber electric dipole moment spectrometer
NASA Astrophysics Data System (ADS)
Serebrov, A. P.; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.; Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.
2015-03-01
This article presents results of measuring the neutron electric dipole moment (EDM) made by the Institut Laue-Langevin (ILL) reactor using the Petersburg Nuclear Physics Institute (PNPI) experimental installation. A double-chamber magnetic resonance spectrometer with prolonged holding of ultracold neutrons has been employed. The results determine the upper limit for EDM neutron quantity equal to | d n | < 5.5 × 10-26 e cm at a 90% confidence level.
11. Compact Electric- And Magnetic-Field Sensor
NASA Technical Reports Server (NTRS)
Winterhalter, Daniel; Smith, Edward
1994-01-01
Compact sensor measures both electric and magnetic fields. Includes both short electric-field dipole and search-coil magnetometer. Three mounted orthogonally providing triaxial measurements of electromagnetic field at frequencies ranging from near 0 to about 10 kHz.
12. Dual aperture dipole magnet with second harmonic component
DOEpatents
Praeg, W.F.
1983-08-31
An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.
13. Dual aperture dipole magnet with second harmonic component
DOEpatents
Praeg, Walter F.
1985-01-01
An improved dual aperture dipole electromagnet includes a second-harmonic frequency magnetic guide field winding which surrounds first harmonic frequency magnetic guide field windings associated with each aperture. The second harmonic winding and the first harmonic windings cooperate to produce resultant magnetic waveforms in the apertures which have extended acceleration and shortened reset portions of electromagnet operation.
14. Regular and chaotic orbits near a massive magnetic dipole
NASA Astrophysics Data System (ADS)
Kovář, Jiří; Kopáček, Ondřej; Karas, Vladimír; Kojima, Yasufumi
2013-01-01
Within the framework of Bonnor's exact solution describing a massive magnetic dipole, we study the motion of neutral and electrically charged test particles. In dependence on the Bonnor spacetime parameters, we determine regions enabling the existence of stable circular orbits confined to the equatorial plane and of those levitating above the equatorial plane. Constructing Poincaré surfaces of section and recurrence plots, we also investigate the dynamics of particles moving along general off-equatorial trajectories bound in effective potential wells forming around the stable circular orbits. We demonstrate that the motion in the Bonnor spacetime is not integrable. This extends previous investigations of generalized Störmer's problem into the realm of exact solutions of Einstein-Maxwell equations, where the gravitational and electromagnetic effects play a comparable role on the particle motion.
15. Electric dipole moments from flavored CP violation in supersymmetry
SciTech Connect
Calibbi, L.; Perez, J. Jones; Vives, O.
2008-10-01
The so-called supersymmetric flavor and CP problems are deeply related to the origin of flavor and hence to the origin of the standard model Yukawa couplings themselves. We show that realistic SU(3) flavor symmetries with spontaneous CP violation reproducing correctly the standard model Yukawa matrices can simultaneously solve both problems without ad hoc modifications of the supersymmetric model. We analyze the leptonic electric dipole moments and lepton flavor violation processes in these models. We show that the electron electric dipole moment and the decay {mu}{yields}e{gamma} are naturally within reach of the proposed experiments if the sfermion masses are measurable at the LHC.
16. Antenna impedance measurements in a magnetized plasma. II. Dipole antenna
SciTech Connect
Blackwell, David D.; Walker, David N.; Messer, Sarah J.; Amatucci, William E.
2007-09-15
This paper presents experimental impedance measurements of a dipole antenna immersed in a magnetized plasma. The impedance was derived from the magnitude and phase of the reflected power using a network analyzer over a frequency range of 1 MHz-1 GHz. The plasma density was varied between 10{sup 7} and 10{sup 10} cm{sup -3} in weakly ({omega}{sub ce}<{omega}{sub pe}) and strongly ({omega}{sub ce}>{omega}{sub pe}) magnetized plasmas in the Space Physics Simulation Chamber at the Naval Research Laboratory. Over this range of plasma conditions the wavelength in the plasma varies from the short dipole limit ({lambda}>>L) to the long dipole limit ({lambda}{approx}L). As with previous impedance measurements, there are two resonant frequencies observed as frequencies where the impedance of the antenna is real. Measurements have indicated that in the short dipole limit the majority of the power deposition takes place at the lower resonance frequency which lies between the cyclotron frequency and the upper hybrid frequency. These measured curves agree very well with the analytic theory for a short dipole in a magnetoplasma. In the long dipole regime, in addition to the short dipole effects still being present, there is resonant energy deposition which peaks at much higher frequencies and correlates to 1/2 and 3/2 wavelength dipole resonances. The wavelengths in the plasma predicted by these resonances are consistent with the antenna radiating R and L-waves.
17. Gyre-driven decay of the Earth's magnetic dipole.
PubMed
Finlay, Christopher C; Aubert, Julien; Gillet, Nicolas
2016-01-01
Direct observations indicate that the magnitude of the Earth's magnetic axial dipole has decreased over the past 175 years; it is now 9% weaker than it was in 1840. Here we show how the rate of dipole decay may be controlled by a planetary-scale gyre in the liquid metal outer core. The gyre's meridional limbs on average transport normal polarity magnetic flux equatorward and reverse polarity flux poleward. Asymmetry in the geomagnetic field, due to the South Atlantic Anomaly, is essential to the proposed mechanism. We find that meridional flux advection accounts for the majority of the dipole decay since 1840, especially during times of rapid decline, with magnetic diffusion making an almost steady contribution generally of smaller magnitude. Based on the morphology of the present field, and the persistent nature of the gyre, the current episode of dipole decay looks set to continue, at least for the next few decades. PMID:26814368
18. Gyre-driven decay of the Earth's magnetic dipole
PubMed Central
Finlay, Christopher C.; Aubert, Julien; Gillet, Nicolas
2016-01-01
Direct observations indicate that the magnitude of the Earth's magnetic axial dipole has decreased over the past 175 years; it is now 9% weaker than it was in 1840. Here we show how the rate of dipole decay may be controlled by a planetary-scale gyre in the liquid metal outer core. The gyre's meridional limbs on average transport normal polarity magnetic flux equatorward and reverse polarity flux poleward. Asymmetry in the geomagnetic field, due to the South Atlantic Anomaly, is essential to the proposed mechanism. We find that meridional flux advection accounts for the majority of the dipole decay since 1840, especially during times of rapid decline, with magnetic diffusion making an almost steady contribution generally of smaller magnitude. Based on the morphology of the present field, and the persistent nature of the gyre, the current episode of dipole decay looks set to continue, at least for the next few decades. PMID:26814368
19. Gyre-driven decay of the Earth's magnetic dipole
NASA Astrophysics Data System (ADS)
Finlay, Christopher C.; Aubert, Julien; Gillet, Nicolas
2016-01-01
Direct observations indicate that the magnitude of the Earth's magnetic axial dipole has decreased over the past 175 years; it is now 9% weaker than it was in 1840. Here we show how the rate of dipole decay may be controlled by a planetary-scale gyre in the liquid metal outer core. The gyre's meridional limbs on average transport normal polarity magnetic flux equatorward and reverse polarity flux poleward. Asymmetry in the geomagnetic field, due to the South Atlantic Anomaly, is essential to the proposed mechanism. We find that meridional flux advection accounts for the majority of the dipole decay since 1840, especially during times of rapid decline, with magnetic diffusion making an almost steady contribution generally of smaller magnitude. Based on the morphology of the present field, and the persistent nature of the gyre, the current episode of dipole decay looks set to continue, at least for the next few decades.
20. Mercury monohalides: suitability for electron electric dipole moment searches.
PubMed
Prasannaa, V S; Vutha, A C; Abe, M; Das, B P
2015-05-01
Heavy polar diatomic molecules are the primary tools for searching for the T-violating permanent electric dipole moment of the electron (eEDM). Valence electrons in some molecules experience extremely large effective electric fields due to relativistic interactions. These large effective electric fields are crucial to the success of polar-molecule-based eEDM search experiments. Here we report on the results of relativistic ab initio calculations of the effective electric fields in a series of molecules that are highly sensitive to an eEDM, the mercury monohalides (HgF, HgCl, HgBr, and HgI). We study the influence of the halide anions on E_{eff}, and identify HgBr and HgI as attractive candidates for future electric dipole moment search experiments. PMID:26000997
1. Properties of the superconductor in accelerator dipole magnets
NASA Astrophysics Data System (ADS)
Teravest, Derk
Several aspects of the application of superconductors to high field dipole magnets for particle accelerators are discussed. The attention is focused on the 10 tesla (1 m model) magnet that is envisaged for the future Large Hadron Collider (LHC) accelerator. The basic motivation behind the study is the intention of employing superconductors to their utmost performance. An overview of practical supercomputers, their applications and their impact on high field dipole magnets used for particle accelerators, is presented. The LHC reference design for the dipole magnets is outlined. Several models were used to study the influence of a number of factors in the shape and in particular, the deviation from the shape that is due to the flux flow state. For the investigated extrinsic and intrinsic factors, a classification can be made with respect to the effect on the shape of the characteristic of a multifilamentary wire. The optimization of the coil structure for high field dipole magnets, with respect to the field quality is described. An analytical model for solid and hollow filaments, to calculate the effect of filament magnetization in the quality of the dipole field, is presented.
2. Electric dipole moments of charged leptons with sterile fermions
NASA Astrophysics Data System (ADS)
Abada, Asmaa; Toma, Takashi
2016-02-01
We address the impact of sterile fermions on charged lepton electric dipole moments. Any experimental signal of these observables calls for scenarios of physics beyond the Standard Model providing new sources of CP violation. In this work, we consider a minimal extension of the Standard Model via the addition of sterile fermions which mix with active neutrinos and we derive the corresponding analytical expressions for the electric dipole moments of charged leptons at two-loop order. Our study reveals that, in order to have a non-vanishing contribution in this framework, the minimal extension necessitates the addition of at least 2 sterile fermion states to the Standard Model field content. Our conclusion is that sterile neutrinos can give significant contributions to the charged lepton electric dipole moments, some of them lying within present and future experimental sensitivity if the masses of the non-degenerate sterile states are both above the electroweak scale. The Majorana nature of neutrinos is also important in order to allow for significative contributions to the charged lepton electric dipole moments. In our analysis we impose all available experimental and observational constraints on sterile neutrinos and we further discuss the prospect of probing this scenario at low and high energy experiments.
3. Screening of nucleon electric dipole moments in nuclei
NASA Astrophysics Data System (ADS)
Inoue, Satoru; Gudkov, Vladimir; Schindler, Matthias R.; Song, Young-Ho
2016-05-01
A partial screening of nucleon electric dipole moments (EDMs) in nuclear systems, which is related to the Schiff mechanism known for neutral atomic systems, is discussed. It is shown that the direct contribution from the neutron EDM to the deuteron EDM is partially screened by about 1% in a zero-range approximation calculation.
4. Review of Electric Dipole Moments of Fundamental Particles
SciTech Connect
Semertzidis, Yannis K.
2009-08-04
Electric dipole moments (EDM) experiments are in the research frontier of CP-violation beyond the standard model (SM). EDM experiments set the current limits on CP-violation beyond the SM and are most likely to be the first ones to discover if nature has indeed chosen that path.
5. Enhancement of the electron electric dipole moment in gadolinium garnets
SciTech Connect
Mukhamedjanov, T.N.; Dzuba, V.A.; Sushkov, O.P.
2003-10-01
Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve the current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. Our calculation accounts for both direct and exchange diagrams.
6. Electric dipole moments of the nucleon and light nuclei
NASA Astrophysics Data System (ADS)
Wirzba, Andreas
2014-08-01
The electric dipole moments of the nucleon and light ions are discussed and strategies for disentangling the underlying sources of CP violation beyond the Kobayashi-Maskawa quark-mixing mechanism of the Standard Model are indicated. Contribution to “45 years of nuclear theory at Stony Brook: a tribute to Gerald E. Brown”.
7. Transitional liquid metal duct flow near a magnetic dipole
NASA Astrophysics Data System (ADS)
Tympel, Saskia; Boeck, Thomas; Schumacher, Joerg
2013-11-01
The flow transformation and the generation of vortex structures by a strong magnetic dipole field in a liquid metal duct flow is studied by means of three-dimensional direct numerical simulations. The dipole is considered as the paradigm for a magnetic obstacle which will deviate the streamlines due to Lorentz forces which act on the fluid elements. The duct is of square cross-section. The dipole is located above the top wall and is centered in spanwise direction. Our model uses the quasi-static approximation which is applicable in the limit of small magnetic Reynolds numbers. The analysis covers the stationary flow regime at small hydrodynamic Reynolds numbers Re as well as the transitional time-dependent regime at higher values which may generate a turbulent flow in the wake of the magnetic obstacle. We present a systematic study of these two basic flow regimes on Re and on the Hartmann number Ha, a measure of the strength of the magnetic dipole field. Furthermore, several orientations and positions of the dipole are compared. The most efficient generation of turbulence at a fixed distance above the duct follows for the spanwise orientation which is caused by a certain configuration of Hartmann layers and reversed flow at the top plate.
8. Do bacteria have an electric permanent dipole moment?
PubMed
Stoylov, S P; Gyurova, A; Georgieva, R; Danova, S
2008-07-15
In the scientific literature in the last 40 years, some data for the permanent dipole moment and the electric polarizability of Escherichia coli can be found [S.P. Stoylov, Colloid Electro-Optics - Theory, Techniques and Application, Academic Press, London, 1991]. In this paper the data based mainly on electro-optic investigation is considered as much as some dipolophoretic (most often called dielectrophoretic) studies. Serious grounds are found to doubt the conclusions made for the electric dipole moments of bacteria by one of the authors of this paper (SPS) and by some other researchers. This concerns both the permanent dipole moment and the electric charge dependent polarizabilities of E. coli. Here, along with the discussion of the old experimental data, new experimental data are shown for a strain of E. coli HB101. The conclusions from the analysis of the old and the new experimental data is that they do not provide correct evidence for the presence of a permanent dipole moment. It seems that all statements for the existence of electric permanent dipole moment in bacteria [S.P. Stoylov, Colloid Electro-Optics - Theory, Techniques and Application, Academic Press, London, 1991; S.P. Stoylov, S. Sokerov, I. Petkanchin, N. Ibroshev, Dokl. AN URSS 180 (1968) 1165; N.A. Tolstoy, A.A. Spartakov, A.A. Trusov, S.A. Schelkunova, Biofizika 11 (1966) 453; V. Morris, B. Jennings, J. Chem. Soc. Faraday Trans. II 71 (1975) 1948; V. Morris, B. Jennings, J. Colloid Interface Sci. 55 (1978) 313; S.P. Stoylov, V.N. Shilov, S.S. Dukhin, S. Sokerov, I. Petkanchin, in: S.S. Dukhin (Ed.), Electro-optics of Colloids, Naukova Dumka, Kiev, 1977 (in Russian).] based on electro-optic studies are result of incorrect interpretation. Therefore, they should be further ignored. PMID:18378431
9. New Experiment to Measure the Electron Electric Dipole Moment
NASA Technical Reports Server (NTRS)
Kittle, Melanie
2003-01-01
An electron can possess an electric dipole moment (edm) only if time reversal symmetry (T) is violated. No edm of any particle has yet been discovered. CP-violation, equivalent to T-violation by the CPT theorem, does occur in Kaon decays and can be accounted for by the standard model. However, this mechanism leads to an electron edm d(sub e) of the order of 10(exp -38) e cm, whereas the current experimental bound on d(sub e) is about 10(exp -27) e cm. However, well-motivated extensions of the standard model such as supersymmetric theories do predict that de could be as large as the current bound. In addition, CP violation in the early universe is required to explain the preponderance of matter over anti-matter, but the exact mechanism of this CP violation is unclear. For these reasons, we are undertaking a new experimental program to determine de to an improved accuracy of 10(exp -29) e cm. Our experiment will use laser-cooled, trapped Cesium atoms to measure the atomic edm d(sub Cs) that occurs if d(sub e) is not zero. In order to do this, we will measure the energy splitting between the atoms spin states in parallel electric and magnetic fields. The signature of an edm would be a linear dependence of the splitting on the electric field E due to the interaction - d(sub Cs) dot E. Our measurement will be much more sensitive than previous measurements because atoms can be stored in the trap for tens of seconds, allowing for much narrower Zeeman resonance linewidths. Also, our method eliminates the most important systematic errors, proportional to atomic velocity, which have limited previous experiments. In this presentation, we will describe the design of our new apparatus, which is presently under construction. An important feature of our experimental apparatus is that magnetic field noise will be suppressed to a very low value of the order of 1 fT/(Hz)1/2. This requires careful attention to the Johnson noise currents in the chamber, which have not been important in previous experiments. In addition we will present estimates of the limits of the various errors that we expect for our experiment.
10. PNPI differential EDM spectrometer and latest results of measurements of the neutron electric dipole moment
NASA Astrophysics Data System (ADS)
Serebrov, A. P.; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.
2015-12-01
In this work, the double chamber magnetic resonance spectrometer of the Petersburg Nuclear Physics Institute (PNPI) designed to measure the neutron electric dipole moment (EDM) is briefly described. A method for long storage of polarized ultracold neutrons in a resonance space with a superposed electric field collinear to the leading magnetic field is used. The results of the measurements carried out on the ILL reactor (Grenoble, France) are interpreted as the upper limit of the value of neutron EDM |dn| < 5.5 × 10-26 e cm at the 90% confidence level.
11. PNPI differential EDM spectrometer and latest results of measurements of the neutron electric dipole moment
SciTech Connect
Serebrov, A. P. Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.
2015-12-15
In this work, the double chamber magnetic resonance spectrometer of the Petersburg Nuclear Physics Institute (PNPI) designed to measure the neutron electric dipole moment (EDM) is briefly described. A method for long storage of polarized ultracold neutrons in a resonance space with a superposed electric field collinear to the leading magnetic field is used. The results of the measurements carried out on the ILL reactor (Grenoble, France) are interpreted as the upper limit of the value of neutron EDM vertical bar d{sub n} vertical bar < 5.5 × 10{sup –26}e cm at the 90% confidence level.
12. Electromagnetic braking revisited with a magnetic point dipole model
NASA Astrophysics Data System (ADS)
Land, Sara; McGuire, Patrick; Bumb, Nikhil; Mann, Brian P.; Yellen, Benjamin B.
2016-04-01
A theoretical model is developed to predict the trajectory of magnetized spheres falling through a copper pipe. The derive magnetic point dipole model agrees well with the experimental trajectories for NdFeB spherical magnets of varying diameter, which are embedded inside 3D printed shells with fixed outer dimensions. This demonstration of electrodynamic phenomena and Lenz's law serves as a good laboratory exercise for physics, electromagnetics, and dynamics classes at the undergraduate level.
13. The consequences of improperly describing oscillator strengths beyond the electric dipole approximation
NASA Astrophysics Data System (ADS)
Lestrange, Patrick J.; Egidi, Franco; Li, Xiaosong
2015-12-01
The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities.
14. The consequences of improperly describing oscillator strengths beyond the electric dipole approximation.
PubMed
Lestrange, Patrick J; Egidi, Franco; Li, Xiaosong
2015-12-21
The interaction between a quantum mechanical system and plane wave light is usually modeled within the electric dipole approximation. This assumes that the intensity of the incident field is constant over the length of the system and transition probabilities are described in terms of the electric dipole transition moment. For short wavelength spectroscopies, such as X-ray absorption, the electric dipole approximation often breaks down. Higher order multipoles are then included to describe transition probabilities. The square of the magnetic dipole and electric quadrupole are often included, but this results in an origin-dependent expression for the oscillator strength. The oscillator strength can be made origin-independent if all terms through the same order in the wave vector are retained. We will show the consequences and potential pitfalls of using either of these two expressions. It is shown that the origin-dependent expression may violate the Thomas-Reiche-Kuhn sum rule and the origin-independent expression can result in negative transition probabilities. PMID:26696042
15. The field of the vertical electric dipole immersed in the heterogeneous half-space
NASA Astrophysics Data System (ADS)
Barsukov, P. O.; Fainberg, E. B.
2014-07-01
The field of the vertical electric dipole (VED) immersed in the heterogeneous conductive halfspace (sea) is analyzed in time domain. In the near field of the source, the amplitudes of the electric and magnetic components of the field are proportional to power 3/2 and power 5/2 of the conductivity of the medium, respectively. After termination of the transmitter pulse, all the VED components decay with time as ˜1/ t 5/2. The possibility of applying the VED field for estimating the electrical properties of the offshore geological sections is demonstrated.
16. Neutron electric dipole moment and possibilities of increasing accuracy of experiments
NASA Astrophysics Data System (ADS)
Serebrov, A. P.; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoshchekova, I. A.; Vasiliev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Aleksandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.
2016-01-01
The paper reports the results of an experiment on searching for the neutron electric dipole moment (EDM), performed on the ILL reactor (Grenoble, France). The double-chamber magnetic resonance spectrometer (Petersburg Nuclear Physics Institute (PNPI)) with prolonged holding of ultra cold neutrons has been used. Sources of possible systematic errors are analyzed, and their influence on the measurement results is estimated. The ways and prospects of increasing accuracy of the experiment are discussed.
17. Bistability between equatorial and axial dipoles during magnetic field reversals.
PubMed
Gissinger, Christophe; Petitdemange, Ludovic; Schrinner, Martin; Dormy, Emmanuel
2012-06-01
Numerical simulations of the geodynamo in the presence of heterogeneous heating are presented. We study the dynamics and the structure of the magnetic field when the equatorial symmetry of the flow is broken. If the symmetry breaking is sufficiently strong, the m=0 axial dipolar field is replaced by a hemispherical magnetic field, dominated by an oscillating m=1 magnetic field. Moreover, for moderate symmetry breaking, a bistability between the axial and the equatorial dipole is observed. In this bistable regime, the axial magnetic field exhibits chaotic switches of its polarity, involving the equatorial dipole during the transition period. This new scenario for magnetic field reversals is discussed within the framework of Earth's dynamo. PMID:23003961
18. Electric dipole moment in the split supersymmetry models
SciTech Connect
Chang, Darwin; Chang, W.-F.; Keung, W.-Y.
2005-04-01
We study an important contribution to the electric dipole moment (EDM) of the electron (or quarks) at the two-loop level due to the W-EDM in the recently proposed scenario of split supersymmetry. This contribution is independent of the Higgs mass, and it can enhance the previous estimation of the electron (neutron) EDM by 20-50% (40-90%). Our formula is new in its analytical form.
19. Current distribution of a VLF electric dipole antenna in the plasmasphere
NASA Astrophysics Data System (ADS)
Bell, T. F.; Inan, U. S.; Chevalier, T.
2006-04-01
In a recent paper (Inan et al., 2003) a method of remediating enhanced energetic electron fluxes in the radiation belt was proposed in which injection of VLF whistler mode waves from spacecraft within the radiation belts would dramatically increase the pitch angle scattering of the relativistic electrons and cause these particles to be rapidly lost from the belts, thereby mitigating the flux enhancement. The VLF wave transmitting system discussed by Inan et al. (2003) involves electric dipole antennas. One of the most important characteristics of such an antenna is the current distribution along the length of the dipole, since it is this current which ultimately determines the amount of VLF power which can be radiated from the antenna into the plasma. In past work it has been assumed without proof that the dipole current has a triangular distribution. In the present work we determine the dipole antenna current distribution from first principles, constructing an integral equation of the Halln type relating the current distribution to the wave vector potential. In this development it is assumed that the length of the thin cylindrical dipole antenna is small compared to the wavelength of whistler mode waves which propagate parallel to the Earth's magnetic field Bo. In the case of the dipole antenna oriented parallel to Bo, it is found that the assumption of a triangular current distribution is reasonable for antenna lengths up to hundreds of meters. For the case of the antenna perpendicular to Bo, it is found that the current decays exponentially along the antenna from the feed points to the antenna ends. In this case we find the conditions under which a triangular current distribution is still a reasonable approximation. We also give the conditions under which the quasi-static model of Balmain (1964) reasonably describes the electric fields associated with the dipole antenna.
20. Quantum electrodynamical corrections to a magnetic dipole in general relativity
NASA Astrophysics Data System (ADS)
Pétri, J.
2016-03-01
Magnetized neutron stars are privileged places where strong electromagnetic fields as high as BQ = 4.4 × 109 T exist, giving rise to non-linear corrections to Maxwell equations described by quantum electrodynamics (QED). These corrections need to be included to the general relativistic (GR) description of a magnetic dipole supposed to be anchored in the neutron star. In this paper, these QED and GR perturbations to the standard flat space-time dipole are calculated to the lowest order in the fine structure constant αsf and to any order in the ratio Rs/R where R is the neutron star radius and Rs its Schwarzschild radius. Following our new 3+1 formalism developed in a previous work, we compute the multipolar non-linear corrections to this dipole and demonstrate the presence of a small dipolar ℓ = 1 and hexapolar ℓ = 3 component.
1. Rheometry Experiment of Electric Dipole Antennas Onboard GEOTAIL
NASA Astrophysics Data System (ADS)
Imachi, T.; Yagitani, S.; Nagano, I.; Higashi, R.; Tsutsui, M.; Matsumoto, H.
2001-12-01
Two components of ac electric field are measured by two pairs of long dipole antennas onboard GEOTAIL spacecraft; the wire antenna (WANT) and the probe antenna (PANT). The frequency range is from dc to 800 kHz. To obtain accurate values of electric field components, we should evaluate an exact antenna effective length and an accurate antenna impedance of each dipole. The antenna impedance has been measured in situ, and the effective lengths have been so far assumed simply as 50 m, half of their tip-to-tip length of 100 m. However it is not easy to estimate actual effective length especially in the low frequency such as several hundreds Hz or lower. In this study, we conduct an experiment of rheometry. A 1/100 scale model of GEOTAIL and its wire antennas are immersed in a water tank with an applied uniform ac electric field. By actually receiving the ac field with the wire antenna attached to the GEOTAIL model, we evaluate various characteristics of the antenna, such as effective lengths, directivity patterns, and frequency responses. We will report the results of the experiment, and discuss the characteristics of the dipole antennas onboard GEOTAIL.
2. Reexamination of the standard model nucleon electric dipole moment
NASA Astrophysics Data System (ADS)
Seng, Chien-Yeah
2015-02-01
The Cabibbo-Kobayashi-Maskawa matrix in the standard model is currently the only experimentally confirmed source of CP violation. The intrinsic electric dipole moment of the nucleon induced by this CP phase via hadronic loop and pole diagrams was studied more than two decades ago, but is subject to various theoretical issues such as the breakdown of chiral power counting and uncertainties in the determination of low energy constants. I carry out an up-to-date re-analysis on both one-loop and pole diagram contributions to the nucleon electric dipole moment based on heavy baryon chiral perturbation theory in a way that preserves power counting, and I redo the determination of the low-energy constants following the results of more recent articles. Combined with an estimation of higher-order contributions, I expect the long-distance contribution to the standard model nucleon electric dipole moment to be approximately (1 ×10-32-6 ×10-32)e cm .
3. A dipole probe for electric field measurements in the LVPD
NASA Astrophysics Data System (ADS)
Srivastava, P. K.; Awasthi, L. M.; Ravi, G.; Kumar, Sunil; Mattoo, S. K.
2016-01-01
This paper describes the design, construction, and calibration of an electric dipole probe and demonstrates its capability by presenting results on the measurement of electric field excited by a ring electrode in the Large Volume Plasma Device (LVPD). It measures the electric field in vacuum and plasma conditions in a frequency range lying between 1-10 \\text{MHz} . The results show that it measures electric field ≥slant 2 mV cm-1 for frequency ≤slant 10 \\text{MHz} . The developed dipole probe works on the principle of amplitude modulation. The probe signal is transmitted through a carrier of 418 MHz, a much higher frequency than the available sources of noise present in the surrounding environment. The amplitude modulation concept of signal transmission is used to make the measurement; it is qualitatively better and less corrupted as it is not affected by the errors introduced by ac pickups. The probe is capable of measuring a variety of electric fields, namely (1) space charge field, (2) time varying field, (3) inductive field and (4) a mixed field containing both space charge and inductive fields. This makes it a useful tool for measuring electric fields in laboratory plasma devices.
4. Self-generated magnetic dipoles in weakly magnetized beam-plasma system.
PubMed
Jia, Qing; Mima, Kunioki; Cai, Hong-bo; Taguchi, Toshihiro; Nagatomo, Hideo; He, X T
2015-02-01
A self-generation mechanism of magnetic dipoles and the anomalous energy dissipation of fast electrons in a magnetized beam-plasma system are presented. Based on two-dimensional particle-in-cell simulations, it is found that the magnetic dipoles are self-organized and play important roles in the beam electron energy dissipation. These dipoles drift slowly in the direction of the return flow with a quasisteady velocity, which depends upon the magnetic amplitude of the dipole and the imposed external magnetic field. This dipole formation provides a mechanism for the anomalous energy dissipation of a relativistic electron beam, which would play an important role in collisionless shock and ion shock acceleration. PMID:25768618
5. Self-generated magnetic dipoles in weakly magnetized beam-plasma system
NASA Astrophysics Data System (ADS)
Jia, Qing; Mima, Kunioki; Cai, Hong-bo; Taguchi, Toshihiro; Nagatomo, Hideo; He, X. T.
2015-02-01
A self-generation mechanism of magnetic dipoles and the anomalous energy dissipation of fast electrons in a magnetized beam-plasma system are presented. Based on two-dimensional particle-in-cell simulations, it is found that the magnetic dipoles are self-organized and play important roles in the beam electron energy dissipation. These dipoles drift slowly in the direction of the return flow with a quasisteady velocity, which depends upon the magnetic amplitude of the dipole and the imposed external magnetic field. This dipole formation provides a mechanism for the anomalous energy dissipation of a relativistic electron beam, which would play an important role in collisionless shock and ion shock acceleration.
6. Electric field meter with a dipole antenna in an elliptically polarized electric field
SciTech Connect
Tokatly, V.I.
1994-07-01
A model of an electric field meter with a dipole antenna is analyzed. The model takes into account the fact that the meter incorporates other elements with a conducting surface in addition to the dipole antenna, viz.: a matching device, a signal cable, and a voltmeter. Alternative forms of the measurement equation are obtained, which differ in the error associated with the currents induced by the measured electric field on the braid of the signal cable and on the casing of the voltmeter. It is shown that this error can be eliminated partially or completely by performing additional measurements with the dipole antenna in different positions.
7. Analytical Field Calculation of Helical Dipole Magnets for RHIC Snake
NASA Astrophysics Data System (ADS)
Tominaka, T.; Okamura, M.; Katayama, T.
1997-05-01
The purpose of this paper is to give the analytical expression for the magnetic field of helical dipole magnets, deriving the multipole coefficients. The helical multipole coefficients are defined so that the non-twist helical multipole coefficients is equal to the conventional 2-dimensional multipole coefficients, and the twist dependence of helical multipole coefficients is studied. The expression of the multipoles for the helical coil will be useful for the helical field analysis. The comparison between the analytical and numerical calculations is presented for the simple helical dipole coils. First of all, it is confirmed that the helical multipole coefficients derived from the numerically calculated field are consistent with those calculated analytically, for a infinitely long helical dipole. Secondly, the comparison between the analytical and numerical calculations for a helical dipole with the finite length is made, and the length dependence of helical dipole field is analyzed. In addition, it is also confirmed that the numerical calculation with OPERA-3d/TOSCA is consistent with this analytical calculation.
8. Constraining the neutrino magnetic dipole moment from white dwarf pulsations
SciTech Connect
Córsico, A.H.; Althaus, L.G.; García-Berro, E. E-mail: [email protected] E-mail: [email protected]
2014-08-01
Pulsating white dwarf stars can be used as astrophysical laboratories to constrain the properties of weakly interacting particles. Comparing the cooling rates of these stars with the expected values from theoretical models allows us to search for additional sources of cooling due to the emission of axions, neutralinos, or neutrinos with magnetic dipole moment. In this work, we derive an upper bound to the neutrino magnetic dipole moment (μ{sub ν}) using an estimate of the rate of period change of the pulsating DB white dwarf star PG 1351+489. We employ state-of-the-art evolutionary and pulsational codes which allow us to perform a detailed asteroseismological period fit based on fully DB white dwarf evolutionary sequences. Plasmon neutrino emission is the dominant cooling mechanism for this class of hot pulsating white dwarfs, and so it is the main contributor to the rate of change of period with time (Pidot) for the DBV class. Thus, the inclusion of an anomalous neutrino emission through a non-vanishing magnetic dipole moment in these sequences notably influences the evolutionary timescales, and also the expected pulsational properties of the DBV stars. By comparing the theoretical Pidot value with the rate of change of period with time of PG 1351+489, we assess the possible existence of additional cooling by neutrinos with magnetic dipole moment. Our models suggest the existence of some additional cooling in this pulsating DB white dwarf, consistent with a non-zero magnetic dipole moment with an upper limit of μ{sub ν} ∼< 10{sup -11} μ{sub B}. This bound is somewhat less restrictive than, but still compatible with, other limits inferred from the white dwarf luminosity function or from the color-magnitude diagram of the Globular cluster M5. Further improvements of the measurement of the rate of period change of the dominant pulsation mode of PG 1351+489 will be necessary to confirm our bound.
9. Detection, localization and classification of multiple dipole-like magnetic sources using magnetic gradient tensor data
NASA Astrophysics Data System (ADS)
Gang, Yin; Yingtang, Zhang; Hongbo, Fan; Zhining, Li; Guoquan, Ren
2016-05-01
We have developed a method for automatic detection, localization and classification (DLC) of multiple dipole sources using magnetic gradient tensor data. First, we define modified tilt angles to estimate the approximate horizontal locations of the multiple dipole-like magnetic sources simultaneously and detect the number of magnetic sources using a fixed threshold. Secondly, based on the isotropy of the normalized source strength (NSS) response of a dipole, we obtain accurate horizontal locations of the dipoles. Then the vertical locations are calculated using magnitude magnetic transforms of magnetic gradient tensor data. Finally, we invert for the magnetic moments of the sources using the measured magnetic gradient tensor data and forward model. Synthetic and field data sets demonstrate effectiveness and practicality of the proposed method.
10. Nucleon electric dipole moments in high-scale supersymmetric models
NASA Astrophysics Data System (ADS)
Hisano, Junji; Kobayashi, Daiki; Kuramoto, Wataru; Kuwahara, Takumi
2015-11-01
The electric dipole moments (EDMs) of electron and nucleons are promising probes of the new physics. In generic high-scale supersymmetric (SUSY) scenarios such as models based on mixture of the anomaly and gauge mediations, gluino has an additional contribution to the nucleon EDMs. In this paper, we studied the effect of the CP -violating gluon Weinberg operator induced by the gluino chromoelectric dipole moment in the high-scale SUSY scenarios, and we evaluated the nucleon and electron EDMs in the scenarios. We found that in the generic high-scale SUSY models, the nucleon EDMs may receive the sizable contribution from the Weinberg operator. Thus, it is important to compare the nucleon EDMs with the electron one in order to discriminate among the high-scale SUSY models.
11. Magnetic dipole-dipole sensing at atomic scale using electron spin resonance STM
NASA Astrophysics Data System (ADS)
Choi, T.; Paul, W.; Rolf-Pissarczyk, S.; MacDonald, A.; Yang, K.; Natterer, F. D.; Lutz, C. P.; Heinrich, A. J.
Magnetometry having both high magnetic field sensitivity and atomic resolution has been an important goal for applications in diverse fields covering physics, material science, and biomedical science. Recent development of electron spin resonance STM (ESR-STM) promises coherent manipulation of spins and studies on magnetic interaction of artificially built nanostructures, leading toward quantum computation, simulation, and sensors In ESR-STM experiments, we find that the ESR signal from an Fe atom underneath a STM tip splits into two different frequencies when we position an additional Fe atom nearby. We measure an ESR energy splitting that decays as 1/r3 (r is the separation of the two Fe atoms), indicating that the atoms are coupled through magnetic dipole-dipole interaction. This energy and distance relation enables us to determine magnetic moments of atoms and molecules on a surface with high precision in energy. Unique and advantageous aspects of ESR-STM are the atom manipulation capabilities, which allow us to build atomically precise nanostructures and examine their interactions. For instance, we construct a dice cinque arrangement of five Fe atoms, and probe their interaction and energy degeneracy. We demonstrate the ESR-STM technique can be utilized for quantum magnetic sensors.
12. Magnetic field properties of Fermilab Energy-Saver dipoles
SciTech Connect
Hanft, R.; Brown, B.C.; Cooper, W.E.; Gross, D.A.; Michelotti, L.; Schmidt, E.E.; Turkot, F.
1983-03-01
At Fermilab we have operated a production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver/Doubler. At any one time 772 of these dipoles are installed in the accelerator and 62 in beamlines; the remainder are spares. Magnetic field data are now available for most of these dipoles; in this paper we present some of these data which show that we have been able to maintain the necessary consistency in field quality throughout the production process. Specifically we report harmonic field coefficients, showing that the mechanical design permits substantial reduction of the magnitudes of the normal and skew quadrupole harmonic coefficients; field shape profiles; integral field data; and field angle data.
13. Decomposing the electromagnetic response of magnetic dipoles to determine the geometric parameters of a dipole conductor
NASA Astrophysics Data System (ADS)
Desmarais, Jacques K.; Smith, Richard S.
2016-03-01
A novel automatic data interpretation algorithm is presented for modelling airborne electromagnetic (AEM) data acquired over resistive environments, using a single-component (vertical) transmitter, where the position and orientation of a dipole conductor is allowed to vary in three dimensions. The algorithm assumes that the magnetic fields produced from compact vortex currents are expressed as a linear combinations of the fields arising from dipoles in the subsurface oriented parallel to the [1, 0, 0], [0, 1, 0], and [0, 0, 1], unit vectors. In this manner, AEM responses can be represented as 12 terms. The relative size of each term in the decomposition can be used to determine geometrical information about the orientation of the subsurface conductivity structure. The geometrical parameters of the dipole (location, depth, dip, strike) are estimated using a combination of a look-up table and a matrix inverted in a least-squares sense. Tests on 703 synthetic models show that the algorithm is capable of extracting most of the correct geometrical parameters of a dipole conductor when three-component receiver data is included in the interpretation procedure. The algorithm is unstable when the target is perfectly horizontal, as the strike is undefined. Ambiguities may occur in predicting the orientation of the dipole conductor if y-component data is excluded from the analysis. Application of our approach to an anomaly on line 15 of the Reid Mahaffy test site yields geometrical parameters in reasonable agreement with previous authors. However, our algorithm provides additional information on the strike and offset from the traverse line of the conductor. Disparities in the values of predicted dip and depth are within the range of numerical precision. The index of fit was better when strike and offset were included in the interpretation procedure. Tests on the data from line 15701 of the Chibougamau MEGATEM survey shows that the algorithm is applicable to situations where three-component AEM data is available.
14. Local spin torque induced by electron electric dipole moment in the YbF molecule
SciTech Connect
Fukuda, Masahiro; Senami, Masato; Ogiso, Yoji; Tachibana, Akitomo
2014-10-06
In this study, we show the modification of the equation of motion of the electronic spin, which is derived by the quantum electron spin vorticity principle, by the effect of the electron electric dipole moment (EDM). To investigate the new contribution to spin torque by EDM, using first principle calculations, we visualize distributions of the local spin angular momentum density and local spin torque density of the YbF molecule on which the static electric field and magnetic field are applied at t = 0.
15. Study By Spin Tracking of A Storage Ring For Deuteron Electric Dipole Moment
SciTech Connect
Lin, F.; Malitsky, N. D.; Luccio, A. U.; Morse, W. M.; Semertzidis, Y. K.; Onderwater, C. J. G.; Orlov, Y. F.
2009-08-04
Spin tracking of polarized deuterons for a proposed experiment to measure a possible Electric Dipole Moment (EDM) of the deuteron was done by using the codes UAL and SPINK. In the experiment the direction of spin polarization will be frozen using crossed electric and magnetic fields. Systematics, in particular the effects of non-linearities of the lattice on a beam with finite emittance and energy spread, have been extensively simulated and the effect of sextuple corrections to increase the spin coherence time has been studied.
16. A radiation hard dipole magnet coils using aluminum clad copper conductors
SciTech Connect
Leonhardt, W.J.
1989-01-01
A C-type septum dipole magnet is located 600 mm downstream of the primary target in an external beam line of the AGS. Conventional use of fiber glass/epoxy electrical insulation for the magnet coils results in their failure after a relatively short running period, therefore a radiation hard insulation system is required. This is accomplished by replacing the existing copper conductor with a copper conductor having a thin aluminum skin which is anodized to provide the electrical insulation. Since the copper supports a current density of 59 A/mm/sup 2/, no reduction in cross sectional area can be tolerated. Design considerations, manufacturing techniques, and operating experience of a prototype dipole is presented. 3 refs., 4 figs.
17. Modeling Barkhausen Noise in magnetic glasses with dipole-dipole interactions
NASA Astrophysics Data System (ADS)
Dubey, Awadhesh K.; Hentschel, H. George E.; Jaiswal, Prabhat K.; Mondal, Chandana; Procaccia, Itamar; Gupta, Bhaskar Sen
2015-10-01
Long-ranged dipole-dipole interactions in magnetic glasses give rise to magnetic domains having labyrinthine patterns on the scale of about 1 micron. Barkhausen Noise then results from the movement of domain boundaries which is modeled by the motion of elastic membranes with random pinning. Here we propose that on the nanoscale new sources of Barkhausen Noise can arise. We propose an atomistic model of magnetic glasses in which we measure the Barkhausen Noise which results from the creation of new domains and the movement of domain boundaries on the nanoscale. The statistics of the Barkhausen Noise found in our simulations is in striking disagreement with the expectations in the literature. In fact we find exponential statistics without any power law, stressing the fact that Barkhausen Noise can belong to very different universality classes. In the present model the essence of the phenomenon is the fact that the spin response Green's function is decaying too rapidly for having sufficiently large magnetic jumps. A theory is offered in excellent agreement with the measured data without any free parameter.
18. Performance of dipole magnets in helium II
SciTech Connect
Althaus, R.; Caspi, S.; Gilbert, W.S.; Hassenzahl, W.; Meuser, R.; Rechen, J.; Taylor, C.; Warren, R.
1981-03-01
Data from tests in He II of four 1-meter-long magnets are presented. The maximum quench current is increased up to 30 percent, compared with tests in He I. Data from calorimetric measurements of heat generated during cyclic operation are presented. Quenches were induced by heaters placed near the conductor, and the energy required to induce quenches in He II and in He I are compared.
19. Full length SSC R and D dipole magnet test results
SciTech Connect
Strait, J.; Bleadon, M.; Brown, B.C.; Hanft, R.; Kuchnir, M.; Lamm, M.; Mantsch, P.; Mazur, P.O.; Orris, D.; Peoples, J.
1989-03-01
Four full scale SSC development dipole magnets have been tested for mechanical and quench behavior. Two are of a design similar to previous magnets but contain a number of improvements, including more uniform coil size, higher pre-stress and a redesigned inner-outer coil splice. One exceeds the SSC operating current on the second quench but the other appears to be limited by damaged superconductor to a lower current. The other two magnets are of alternate designs. One trains erratically and fails to reach a plateau and the other reaches plateau after four quenches. 12 refs., 4 figs.
20. Construction techniques for short iron-free dipole magnets
SciTech Connect
Harvey, A.R.
1983-11-08
A method was developed for economically fabricating short, wire-wound, steering magnets with maximum length, cosine-distributed, axial elements. This method utilizes multifunctional tooling to precisely flat-wind two-layer dipole halves that are subsequently reformed and encapsulated into semicylindrical form with confinement of the end turns into thin, half discs normal to the magnet axis. This paper addresses the magnet fabrication in detail, highlighting the inherent quality control features of the tooling, overall construction costs, and contemplated manufacturing enhancements.
1. Electric dipole induced by gravity in fat branes
NASA Astrophysics Data System (ADS)
Dahia, F.; de Albuquerque Silva, Alex; Romero, C.
2014-05-01
In the fat brane model, also known as the split fermion model, it is assumed that leptons and baryons live in different hypersurfaces of a thick brane in order to explain the proton stability without invoking any symmetry. It turns out that, in the presence of a gravity source M, particles will see different four-dimensional (4D) geometries and hence, from the point of view of 4D-observers, the equivalence principle will be violated. As a consequence, we show that a hydrogen atom in the gravitational field of M will acquire a radial electric dipole. This effect is regulated by the Hamiltonian Hd=-μAṡδr, which is the gravitational analog of the Stark Hamiltonian, where the electric field is replaced by the tidal acceleration A due to the split of fermions in the brane and the atomic reduced mass μ substitutes the electric charge.
2. Candidate molecular ions for an electron electric dipole moment experiment
SciTech Connect
Meyer, Edmund R.; Bohn, John L.; Deskevich, Michael P.
2006-06-15
This paper is a theoretical work in support of a newly proposed experiment [R. Stutz and E. Cornell, Bull. Am. Soc. Phys. 89, 76 (2004)] that promises greater sensitivity to measurements of the electron's electric dipole moment (EDM) based on the trapping of molecular ions. Such an experiment requires the choice of a suitable molecule that is both experimentally feasible and possesses an expectation of a reasonable EDM signal. We find that the molecular ions PtH{sup +} and HfH{sup +} are both suitable candidates in their low-lying {sup 3}{delta} states. In particular, we anticipate that the effective electric fields generated inside these molecules are approximately 73 and -17 GV/cm, respectively. As a byproduct of this discussion, we also explain how to make estimates of the size of the effective electric field acting in a molecule, using commercially available nonrelativistic molecular structure software.
3. A simple experiment showing the determination of the magnetic dipole moment of a permanent disc magnet
NASA Astrophysics Data System (ADS)
Amrani, D.
2015-03-01
We propose a simple experiment to estimate the magnetic dipole moment of a neodymium disc magnet. The experiment employs a precision digital balance and a 1 m ruler to measure the force between two magnets. The magnetic dipole moment is determined from the slope of the magnetic force as a function of the inverse fourth power of the distance. The presented activity can be performed by teachers and students at college or university level to enhance their knowledge of the physics of magnetism.
4. Parity-violating electric-dipole transitions in helium
NASA Technical Reports Server (NTRS)
Hiller, J.; Sucher, J.; Bhatia, A. K.; Feinberg, G.
1980-01-01
The paper examines parity-violating electric-dipole transitions in He in order to gain insight into the reliability of approximate calculations which are carried out for transitions in many-electron atoms. The contributions of the nearest-lying states are computed with a variety of wave functions, including very simple product wave functions, Hartree-Fock functions and Hylleraas-type wave functions with up to 84 parameters. It is found that values of the matrix elements of the parity-violating interaction can differ considerably from the values obtained from the good wave functions, even when these simple wave functions give accurate values for the matrix elements in question
5. Reappraisal of the Electric Dipole Moment Enhancement Factor for Thallium
SciTech Connect
Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Mukherjee, D.
2011-05-20
The electric dipole moment (EDM) enhancement factor of atomic Tl is of considerable interest as it has been used in determining the most accurate limit on the electron EDM to date. However, its value varies from -179 to -1041 in different approximations. In view of the large uncertainties associated with many of these calculations, we perform an accurate calculation employing the relativistic coupled-cluster theory and obtain -466, which in combination with the most accurate measurement of Tl EDM [Phys. Rev. Lett. 88, 071805 (2002)] yields a new limit for the electron EDM: |d{sub e}|<2.0x10{sup -27}e cm.
6. Status and Prospects of Electric Dipole Moment Measurements
NASA Astrophysics Data System (ADS)
Cianciolo, Vince
2015-10-01
Precision electric dipole moment (EDM) measurements are extremely sensitive to non-Standard Model sources of charge/parity violation required for generation of the observed matter/anti-matter asymmetry in the universe. Many experiments in many systems are underway. In a half-hour talk it is difficult to do more than scratch the surface, but I will attempt to give a high-level overview on the various ongoing efforts. Research sponsored by the Office of Nuclear Physics, US Department of Energy.
7. T violation in radiative β decay and electric dipole moments
NASA Astrophysics Data System (ADS)
Dekens, W.; Vos, K. K.
2015-12-01
In radiative β decay, T violation can be studied through a spin-independent T-odd correlation. We consider contributions to this correlation by beyond the standard model (BSM) sources of T-violation, arising above the electroweak scale. At the same time such sources, parametrized by dimension-6 operators, can induce electric dipole moments (EDMs). As a consequence, the manifestations of the T-odd BSM physics in radiative β decay and EDMs are not independent. Here we exploit this connection to show that current EDM bounds already strongly constrain the spin-independent T-odd correlation in radiative β decay.
8. The permanent electric dipole moment of chromium monoxide
NASA Technical Reports Server (NTRS)
Steimle, Timothy C.; Nachman, David F.; Shirley, Jeffrey E.; Bauschlicher, Charles W.; Langhoff, Stephen R.
1989-01-01
The permanent electric dipole moments for the X 5Pi and B 5pi states of gas-phase CrO have been experimentally determined using the sub-Doppler optical technique of intermodulated fluorescence spectroscopy in conjunction with the Stark effect. The measured values are 3.88 + or - 0.13 and 4.1 + or - 1.8 D for the X and B states, respectively. The theoretical values determined for the X state using multireference CI iterative-natural-orbital and finite-field calculations are in excellent agreement with the experimental value.
9. Equilibrium values and dynamics of the net magnetic moment of a system of magnetic dipoles
SciTech Connect
Shutyi, A. M.
2010-02-15
Equilibrium states of different systems formed by coupled spherical bodies with dipole magnetic moments have been investigated using a numerical analysis. The bistable states and the corresponding values of the net magnetic moment are determined for a number of planar and three-dimensional systems of dipoles, and the conditions providing the existence of orientational configurations of coupled dipoles involved in the bistability are analyzed. The disturbances of the magnetic moment due to the quasi-static passage of an additional dipole and the dynamic modes excited by a homogeneous alternating magnetic field and represented by periodic, quasi-periodic, and chaotic oscillations of the magnetic moment of the system are considered for several types of systems. The bifurcation diagrams of the dynamic modes are constructed, and the specific features typical of the systems under consideration are revealed.
10. Point dipole as a magnetic obstacle in liquid metal duct flow
NASA Astrophysics Data System (ADS)
Tympel, Saskia; Boeck, Thomas; Krasnov, Dmitry; Schumacher, Jörg
2011-11-01
Lorentz force velocimetry is a new contactless technique to measure the velocities of hot and agressive conductiong liquids. The measurement of the Lorentz force on the magnet is highly sensitive to the velocity profile that is influenced by the magnetic field. Thus the knowlegde of the flow transformation and the influence of an inhomogeneous local magnetic field on liquid metal flow is essential for obtaining velocity information from the measured forces. We consider liquid metal flow in a square duct with electrically insulating walls under the influence of a magnetic point dipole using three-dimensional direct numerical simulations with a finite-difference method. The dipole acts as a magnetic obstacle. A wide range of parameters affects the created wake. In this canonical setting, we study the modification of the flow for different Hartmann and Reynolds numbers. We observe a strong dependence of the magnetic obstacle effect and the corresponding Lorentz force on the orientation of the dipole as well as on its position. The authors acknowledge the support of the Deutsche Forschungsgemeinschaft.
11. New experimental limit on the electric dipole moment of the electron in a paramagnetic insulator
NASA Astrophysics Data System (ADS)
Kim, Y. J.; Liu, C.-Y.; Lamoreaux, S. K.; Visser, G.; Kunkler, B.; Matlashov, A. N.; Long, J. C.; Reddy, T. G.
2015-05-01
We report results of an experimental search for the intrinsic electric dipole moment of the electron (eEDM) using a solid-state technique. The experiment employs a paramagnetic, insulating gadolinium gallium garnet (GGG) that has a large magnetic response at low temperatures. The presence of the eEDM would lead to a small but nonzero magnetization as the GGG sample is subjected to a strong electric field. We search for the resulting Stark-induced magnetization with a sensitive magnetometer. Recent progress on the suppression of several sources of background allows the experiment to run free of spurious signals at the level of the statistical uncertainties. We report our first limit on the eEDM of (-5.57 ±7.98 ±0.12 )×10-25 e cm with 5 days of data averaging.
12. Dipole-dipole interaction and its concentration dependence of magnetic fluid evaluated by alternating current hysteresis measurement
NASA Astrophysics Data System (ADS)
Ota, Satoshi; Yamada, Tsutomu; Takemura, Yasushi
2015-05-01
Magnetic nanoparticles (MNPs) are used as therapeutic and diagnostic tools, such as for treating hyperthermia and in magnetic particle imaging, respectively. Magnetic relaxation is one of the heating mechanisms of MNPs. Brownian and Néel relaxation times are calculated conventional theories; however, the influence of dipole-dipole interactions has not been considered in conventional models. In this study, water-dispersed MNPs of different concentrations and MNPs fixed with an epoxy bond were prepared. dc and ac hysteresis loops for each sample were measured. With respect to both dc and ac hysteresis loops, magnetization decreased with the increase in MNP concentration because of inhibition of magnetic moment rotation due to dipole-dipole interactions. Moreover, intrinsic loss power (ILP) was estimated from the areas of the ac hysteresis loops. The dependence of ILP on the frequency of the magnetic field was evaluated for each MNP concentration. The peak frequency of ILP increased with the decrease in MNP concentration. These peaks were due to Brownian relaxation, as they were not seen with the fixed sample. This indicates that the Brownian relaxation time became shorter with lower MNP concentration, because the weaker dipole-dipole interactions with lower concentrations suggested that the magnetic moments could rotate more freely.
13. Probing magnetic and electric optical responses of silicon nanoparticles
SciTech Connect
Permyakov, Dmitry; Sinev, Ivan; Markovich, Dmitry; Samusev, Anton; Belov, Pavel; Ginzburg, Pavel; Valuckas, Vytautas; Kuznetsov, Arseniy I.; Luk'yanchuk, Boris S.; Miroshnichenko, Andrey E.; Neshev, Dragomir N.; Kivshar, Yuri S.
2015-04-27
We study experimentally both magnetic and electric optically induced resonances of silicon nanoparticles by combining polarization-resolved dark-field spectroscopy and near-field scanning optical microscopy measurements. We reveal that the scattering spectra exhibit strong sensitivity of electric dipole response to the probing beam polarization and attribute the characteristic asymmetry of measured near-field patterns to the excitation of a magnetic dipole mode. The proposed experimental approach can serve as a powerful tool for the study of photonic nanostructures possessing both electric and magnetic optical responses.
14. Magnetic dipole sequences in {sup 83}Rb
SciTech Connect
Schwengner, R.; Schnare, H.; Wagner, A.; Doenau, F.; Rainovski, G.; Frauendorf, S.; Jungclaus, A.; Hausmann, M.; Lieb, K. P.; Yordanov, O.; Napoli, D. R.; De Angelis, G.; Axiotis, M.; Marginean, N.; Brandolini, F.; Alvarez, C. Rossi
2009-10-15
High-spin states in {sup 83}Rb were populated in the reaction {sup 11}B+{sup 76}Ge at beam energies of 45 and 50 MeV. {gamma} rays were detected with the spectrometer GASP. The level scheme of {sup 83}Rb was extended up to 13.9 MeV. Mean lifetimes of 23 levels were determined using the Doppler-shift-attenuation method. Among the bands newly established is a sequence comprising intense M1 transitions and crossover E2 transitions. This sequence turns out to be irregular and thus shows that magnetic rotation as observed in the neighboring odd-odd isotopes is not realized in this odd-even nuclide. Excited states in {sup 83}Rb were interpreted in terms of the shell model using the model space {pi}(0f{sub 5/2},1p{sub 3/2},1p{sub 1/2},0g{sub 9/2}) {nu}(1p{sub 1/2},0g{sub 9/2}). The configurations predicted for the negative-parity M1 sequence reproduce the M1 transition strengths fairly well.
15. Electric dipole polarizabilities of hydrogen and helium isotopes
SciTech Connect
Stetcu, I; Friar, J; Hayes, A C; Quaglioni, S
2009-01-01
The electric dipole polarizabilities of {sup 3}H, {sup 3}He, and {sup 4}He are calculated directly using the Schroedinger equation with the latest generation of two- and three-nucleon interactions. These quantities are necessary in order to obtain accurate nuclear-polarization corrections for transitions involving S-waves in one-and two-electron atoms. Our results are compared to previous results, and it is shown that direct calculations of the electric polarizability of {sup 4}He using modern nuclear potentials are smaller than published values calculated using experimental photoabsorption data. The status of this topic is assessed in the context of precise measurements of transitions in one- and two-electron atoms.
16. Influence of magnetization on field quality in cosine-theta and block design dipole magnets wound with coated conductors
NASA Astrophysics Data System (ADS)
Sogabe, Yusuke; Sakashita, Masaki; Nakamura, Taketsune; Ogitsu, Toru; Amemiya, Naoyuki
2016-04-01
We carried out electromagnetic field analyses on the cross sections of two dipole magnets wound with coated conductors. One was a cosine-theta magnet, and the other was a block design magnet. The electric field-current density characteristics of the coated conductors were formulated using a percolation depinning model based on the measured voltage-current characteristics. We calculated the temporal evolutions of the current-density distributions in all the turns of each magnet and used these evolutions to calculate the multipole components of the magnetic field. We compared the two magnets, which differed in coated-conductor orientations, regarding the influence of coated-conductor magnetization on the field qualities.
17. Electric dipole moment searches: Effect of linear electric field frequency shifts induced in confined gases
SciTech Connect
Barabanov, A. L.; Golub, R.; Lamoreaux, S. K.
2006-11-15
The search for particle electric dipole moments (EDM's) represents a most promising way to search for physics beyond the standard model. A number of groups are planning a new generation of experiments using stored gases of various kinds. In order to achieve the target sensitivities it will be necessary to deal with the systematic error resulting from the interaction of the well-known v-vectorxE-vector field with magnetic field gradients which is often referred to as the geometric phase effect [E. D. Commins, Am. J. Phys. 59, 1077 (1991); J. M. Pendlebury et al., Phys. Rev. A 70, 032102 (2004)]. This interaction produces a frequency shift linear in the electric field, mimicking an EDM. In this work we introduce an analytic form for the velocity autocorrelation function which determines the velocity-position correlation function which in turn determines the behavior of the frequency shift [S. K. Lamoreaux and R. Golub, Phys. Rev A 71, 032104 (2005)] and show how it depends on the operating conditions of the experiment. We also discuss some additional issues.
18. Visualizing Special Relativity: The Field of An Electric Dipole Moving at Relativistic Speed
ERIC Educational Resources Information Center
Smith, Glenn S.
2011-01-01
The electromagnetic field is determined for a time-varying electric dipole moving with a constant velocity that is parallel to its moment. Graphics are used to visualize this field in the rest frame of the dipole and in the laboratory frame when the dipole is moving at relativistic speed. Various phenomena from special relativity are clearly…
19. Visualizing Special Relativity: The Field of An Electric Dipole Moving at Relativistic Speed
ERIC Educational Resources Information Center
Smith, Glenn S.
2011-01-01
The electromagnetic field is determined for a time-varying electric dipole moving with a constant velocity that is parallel to its moment. Graphics are used to visualize this field in the rest frame of the dipole and in the laboratory frame when the dipole is moving at relativistic speed. Various phenomena from special relativity are clearly
20. Strong dependence of ultracold chemical rates on electric dipole moments
SciTech Connect
Quemener, Goulven; Bohn, John L.
2010-02-15
We use the quantum threshold laws combined with a classical capture model to provide an analytical estimate of the chemical quenching cross sections and rate coefficients of two colliding particles at ultralow temperatures. We apply this quantum threshold model (QT model) to indistinguishable fermionic polar molecules in an electric field. At ultracold temperatures and in weak electric fields, the cross sections and rate coefficients depend only weakly on the electric dipole moment d induced by the electric field. In stronger electric fields, the quenching processes scale as d{sup 4(L+(1/2))} where L>0 is the orbital angular-momentum quantum number between the two colliding particles. For p-wave collisions (L=1) of indistinguishable fermionic polar molecules at ultracold temperatures, the quenching rate thus scales as d{sup 6}. We also apply this model to pure two-dimensional collisions and find that chemical rates vanish as d{sup -4} for ultracold indistinguishable fermions. This model provides a quick and intuitive way to estimate chemical rate coefficients of reactions occuring with high probability.
1. Electric dipole radiation at VLF in a uniform warm magneto-plasma.
NASA Technical Reports Server (NTRS)
Wang, T. N. C.; Bell, T. F.
1972-01-01
Use of a linear full electromagnetic wave theory to calculate the input impedance of an electric antenna embedded in a uniform, lossless, unbounded warm magnetoplasma, which is assumed to consist of warm electrons and cold ions. In calculating the dipole radiation resistance for the thermal modes and the thermally modified whistler mode the analysis includes the finite temperature only for the electrons. In deriving the formal solution of the warm plasma dipole input impedance a full-wave analysis is used and two antenna orientations are considered, parallel and perpendicular to the static magnetic field. A general dispersion equation governing the modes of propagation is derived and a detailed analysis is made of the propagation characteristics of these modes.
2. Magnetic dipole super-resonances and their impact on mechanical forces at optical frequencies.
PubMed
Liberal, Iigo; Ederra, Iigo; Gonzalo, Ramn; Ziolkowski, Richard W
2014-04-01
Artificial magnetism enables various transformative optical phenomena, including negative refraction, Fano resonances, and unconventional nanoantennas, beamshapers, polarization transformers and perfect absorbers, and enriches the collection of electromagnetic field control mechanisms at optical frequencies. We demonstrate that it is possible to excite a magnetic dipole super-resonance at optical frequencies by coating a silicon nanoparticle with a shell impregnated with active material. The resulting response is several orders of magnitude stronger than that generated by bare silicon nanoparticles and is comparable to electric dipole super-resonances excited in spaser-based nanolasers. Furthermore, this configuration enables an exceptional control over the optical forces exerted on the nanoparticle. It expedites huge pushing or pulling actions, as well as a total suppression of the force in both far-field and near-field scenarios. These effects empower advanced paradigms in electromagnetic manipulation and microscopy. PMID:24718235
3. Space propulsion by fusion in a magnetic dipole
SciTech Connect
Teller, E.; Glass, A.J.; Fowler, T.K. ); Hasegawa, A. ); Santarius, J.F. . Fusion Technology Inst.)
1991-04-12
A conceptual design is discussed for a fusion rocket propulsion system based on the magnetic dipole configuration. The dipole is found to have features well suited to space applications. Example parameters are presented for a system producing a specific power of 1 kW/kg, capable of interplanetary flights to Mars in 90 days and to Jupiter in a year, and of extra-solar-system flights to 1000 astronomical units (the Tau mission) in 20 years. This is about 10 times better specific power toward 10 kW/kg are discussed, as in an approach to implementing the concept through proof-testing on the moon. 21 refs., 14 figs., 2 tabs.
4. Enhancement of magnetic dipole emission at yellow light in optical metamaterials
NASA Astrophysics Data System (ADS)
Hu, Wenliang; Yi, Ningbo; Sun, Shang; Cui, Lin; Song, Qinghai; Xiao, Shumin
2015-09-01
Here we demonstrate the control of magnetic dipole spontaneous emission at yellow light by magnetic metamaterials. By embedding magnetic dipole into a magnetic metamaterial consisting of arrays of paired silver strips, the radiative emission enhancement and the Purcell factor around 590 nm has been dramatically increased to 110 and 180 respectively. Moreover, the enhancements are found to be robust to variation of dipole's positions and structure geometries, showing nice fabrication tolerance for practical applications.
5. Electrically controlled nonreciprocity inversion of microwave transmission in a metastructure based on ferrite and a varactor-loaded dipole
NASA Astrophysics Data System (ADS)
Kraftmakher, G. A.; Butylkin, V. S.; Kazantsev, Yu. N.
2015-08-01
A possibility of electrical control of nonreciprocity inversion of microwave propagation when using a metastructure with a ferrite plate and varactor-loaded dipole is demonstrated. In contrast to conven-tional methods, the inversion occurs without ferrite remagnetization. It is reached by varying the constant bias voltage on varactor that enables the tuning of the resonance frequency of dipole to the frequency of ferromagnetic resonance. This effect occurs due to the fact that a magnetic field with elliptical polarization is formed near a dipole as a result of superposition of incident and scattered waves, rotating in one direction below the resonance frequency of dipole and in the opposite direction above the frequency of this resonance.
6. Improved Experimental Limit on the Electric Dipole Moment of the Neutron
SciTech Connect
Baker, C. A.; Iaydjiev, P.; Ivanov, S. N.; Doyle, D. D.; Harris, P. G.; May, D. J. R.; Pendlebury, J. M.; Richardson, J. D.; Shiers, D.; Smith, K. F.; Geltenbort, P.; Green, K.; Grinten, M. G. D. van der
2006-09-29
An experimental search for an electric dipole moment (EDM) of the neutron has been carried out at the Institut Laue-Langevin, Grenoble. Spurious signals from magnetic-field fluctuations were reduced to insignificance by the use of a cohabiting atomic-mercury magnetometer. Systematic uncertainties, including geometric-phase-induced false EDMs, have been carefully studied. The results may be interpreted as an upper limit on the neutron EDM of vertical bar d{sub n} vertical bar <2.9x10{sup -26}e cm (90% C.L.)
7. Electric Field-Driven Water Dipoles: Nanoscale Architecture of Electroporation
PubMed Central
Tokman, Mayya; Lee, Jane HyoJin; Levine, Zachary A.; Ho, Ming-Chak; Colvin, Michael E.; Vernier, P. Thomas
2013-01-01
Electroporation is the formation of permeabilizing structures in the cell membrane under the influence of an externally imposed electric field. The resulting increased permeability of the membrane enables a wide range of biological applications, including the delivery of normally excluded substances into cells. While electroporation is used extensively in biology, biotechnology, and medicine, its molecular mechanism is not well understood. This lack of knowledge limits the ability to control and fine-tune the process. In this article we propose a novel molecular mechanism for the electroporation of a lipid bilayer based on energetics analysis. Using molecular dynamics simulations we demonstrate that pore formation is driven by the reorganization of the interfacial water molecules. Our energetics analysis and comparisons of simulations with and without the lipid bilayer show that the process of poration is driven by field-induced reorganization of water dipoles at the water-lipid or water-vacuum interfaces into more energetically favorable configurations, with their molecular dipoles oriented in the external field. Although the contributing role of water in electroporation has been noted previously, here we propose that interfacial water molecules are the main players in the process, its initiators and drivers. The role of the lipid layer, to a first-order approximation, is then reduced to a relatively passive barrier. This new view of electroporation simplifies the study of the problem, and opens up new opportunities in both theoretical modeling of the process and experimental research to better control or to use it in new, innovative ways. PMID:23593404
8. Hadronic electric dipole moments in R-parity violating supersymmetry
SciTech Connect
Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.; Kovalenko, Sergey
2006-06-01
We calculate the electric dipole moments (EDM) of the neutral {sup 199}Hg atom, neutron and deuteron within a generic R-parity violating SUSY model (Re{sub p} SUSY) on the basis of a one-pion-exchange model with CP-odd pion-nucleon interactions. We consider two types of the Re{sub p} SUSY contributions to the above hadronic EDMs: via the quark chromoelectric dipole moments (CEDM) and CP-violating 4-quark interactions. We demonstrate that the former contributes to all the three studied EDMs while the latter appears only in the nuclear EDMs via the CP-odd nuclear forces. We find that the Re{sub p} SUSY induced 4-quark interactions arise at tree level through the sneutrino exchange and involve only s and b quarks. Therefore, their effect in hadronic EDMs is determined by the strange and bottom-quark sea of the nucleon. From the null experimental results on the hadronic EDMs we derive the limits on the imaginary parts of certain products Im({lambda}{sup '}{lambda}{sup '}*) of the trilinear Re{sub p}-couplings and show that the currently best limits come from the {sup 199}Hg EDM experiments. We demonstrate that some of these limits are better than those existing in the literature. We argue that future storage ring experiments on the deuteron EDM are able to improve these limits by several orders of magnitude.
9. Electric field-driven water dipoles: nanoscale architecture of electroporation.
PubMed
Tokman, Mayya; Lee, Jane HyoJin; Levine, Zachary A; Ho, Ming-Chak; Colvin, Michael E; Vernier, P Thomas
2013-01-01
Electroporation is the formation of permeabilizing structures in the cell membrane under the influence of an externally imposed electric field. The resulting increased permeability of the membrane enables a wide range of biological applications, including the delivery of normally excluded substances into cells. While electroporation is used extensively in biology, biotechnology, and medicine, its molecular mechanism is not well understood. This lack of knowledge limits the ability to control and fine-tune the process. In this article we propose a novel molecular mechanism for the electroporation of a lipid bilayer based on energetics analysis. Using molecular dynamics simulations we demonstrate that pore formation is driven by the reorganization of the interfacial water molecules. Our energetics analysis and comparisons of simulations with and without the lipid bilayer show that the process of poration is driven by field-induced reorganization of water dipoles at the water-lipid or water-vacuum interfaces into more energetically favorable configurations, with their molecular dipoles oriented in the external field. Although the contributing role of water in electroporation has been noted previously, here we propose that interfacial water molecules are the main players in the process, its initiators and drivers. The role of the lipid layer, to a first-order approximation, is then reduced to a relatively passive barrier. This new view of electroporation simplifies the study of the problem, and opens up new opportunities in both theoretical modeling of the process and experimental research to better control or to use it in new, innovative ways. PMID:23593404
10. Efficient injection of an intense positron beam into a dipole magnetic field
NASA Astrophysics Data System (ADS)
Saitoh, H.; Stanja, J.; Stenson, E. V.; Hergenhahn, U.; Niemann, H.; Pedersen, T. Sunn; Stoneking, M. R.; Piochacz, C.; Hugenschmidt, C.
2015-10-01
We have demonstrated efficient injection and trapping of a cold positron beam in a dipole magnetic field configuration. The intense 5 eV positron beam was provided by the NEutron induced POsitron source MUniCh facility at the Heinz Maier-Leibnitz Zentrum, and transported into the confinement region of the dipole field trap generated by a supported, permanent magnet with 0.6 T strength at the pole faces. We achieved transport into the region of field lines that do not intersect the outer wall using the {E}× {B} drift of the positron beam between a pair of tailored plates that created the electric field. We present evidence that up to 38% of the beam particles are able to reach the intended confinement region and make at least a 180° rotation around the magnet where they annihilate on an insertable target. When the target is removed and the {E}× {B} plate voltages are switched off, confinement of a small population persists for on the order of 1 ms. These results lend optimism to our larger aims to apply a magnetic dipole field configuration for trapping of both positrons and electrons in order to test predictions of the unique properties of a pair plasma.
11. Lepton Dipole Moments
NASA Astrophysics Data System (ADS)
Roberts, B. Lee
2004-02-01
From the famous experiments of Stern and Gerlach to the present, measurements of magnetic dipole moments, and searches for electric dipole moments of "elementary" particles have played a major role in our understanding of sub-atomic physics. In this talk I discuss the progress on measurements and theory of the magnetic dipole moments of the electron and muon. I also discuss a new proposal to search for a permanent electric dipole moment (EDM) of the muon and put it into the more general context of other EDM searches.
12. Electric-dipole sum rule in nuclear matter
NASA Astrophysics Data System (ADS)
Fabrocini, A.; Fantoni, S.
1985-03-01
The enhancement factor K in the electric-dipole sum rule for some realistic models of symmetrical nuclear matter is calculated using variational theory. The nuclear-matter wave function used contains central, spin, isospin, tensor and spin-orbit pair correlations. The non-central correlations, particularly the tensor one, give the major contribution to K. At experimental equilibrium density K. turns out to be ≈ 1.8, of which 65% comes from OPEP and 30% from the short-range part of the interaction. The two-pion-exchange three-nucleon interaction contributes ≈ 0.2% and is cancelled, to a large extent, by the contribution due to the intermediate-range two-body potential. The relationship of the summed oscillator strength with the effective mass is also discussed.
13. Thermal annealing-induced electric dipole relaxation in natural alexandrite
NASA Astrophysics Data System (ADS)
Scalvi, Rosa M. Fernandes; Li, Maximo Siu; Scalvi, Luis V. A.
2005-02-01
Electrical properties of natural alexandrite (BeAl2O4:Cr3+) are investigated by the thermally stimulated depolarization current (TSDC) technique. Samples are submitted to consecutive annealing processes and TSDC is carried out after each annealing, yielding bands with different parameters. These bands are fitted by a continuous distribution of relaxation parameters: activation energy and pre-exponential factor of the Arrhenius equation. It has been observed that annealing influences the dipole relaxation behavior, since it promotes a modification of Fe3+ and Cr3+ impurity distributions on sites of distinct symmetry: Al1 and Al2. In order to have a reference for comparison, TSDC is also carried out on a synthetic alexandrite sample, where the only impurity present is Cr3+ ion.
14. Electric dipole moment constraints on minimal electroweak baryogenesis
SciTech Connect
Huber, Stephan J.; Pospelov, Maxim; Ritz, Adam
2007-02-01
We study the simplest generic extension of the standard model which allows for conventional electroweak baryogenesis, through the addition of dimension-six operators in the Higgs sector. At least one such operator is required to be CP-odd, and we study the constraints on such a minimal setup, and related scenarios with minimal flavor violation, from the null results of searches for electric dipole moments (EDMs), utilizing the full set of two-loop contributions to the EDMs. The results indicate that the current bounds are stringent, particularly that of the recently updated neutron EDM, but fall short of ruling out these scenarios. The next generation of EDM experiments should be sufficiently sensitive to provide a conclusive test.
15. Improved limit on the muon electric dipole moment
SciTech Connect
Bennett, G. W.; Brown, H. N.; Bunce, G.; Danby, G. T.; Larsen, R.; Lee, Y. Y.; Meng, W.; Mi, J.; Morse, W. M.; Nikas, D.; Prigl, R.; Semertzidis, Y. K.; Warburton, D.; Bousquet, B.; Cushman, P.; Duong, L.; Giron, S.; Kindem, J.; Kronkvist, I.; Qian, T.
2009-09-01
Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muons, as well as the combined result, d{sub {mu}}=(0.0{+-}0.9)x10{sup -19}e cm, are all consistent with zero, we set a new muon EDM limit, |d{sub {mu}}|<1.8x10{sup -19}e cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.
16. Nuclear electric dipole moment of {sup 3}He
SciTech Connect
Stetcu, I.; Friar, J. L.; Hayes, A. C.; Liu, C.-P.; Navratil, P.
2009-01-28
In the no-core shell model (NCSM) framework, we calculate the {sup 3}He electric dipole moment (EDM) generated by parity- and time-reversal violation in the nucleon-nucleon interaction. While the results are somehow sensitive to the interaction model chosen for the strong two- and three-body interactions, we demonstrate the pion-exchange dominance to the EDM of {sup 3}He, if the coupling constants for {pi}, {rho} and {omega}-exchanges are of comparable magnitude, as expected. Finally, our results suggest that a measurement of {sup 3}He EDM would be complementary to the currently planned neutron and deuteron experiments, and would constitute a powerful constraint to the models of the pion P- and T-violating interactions.
17. The permanent electric dipole moment of CaOH
NASA Technical Reports Server (NTRS)
Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Steimle, Timothy; Shirley, Jeffrey E.
1990-01-01
The X 2 Sigma(+), A 2Pi, and B 2Sigma(+) states of CaOH are characterized theoretically and experimentally, with a focus on the value of the permanent electric dipole moment (mu). Calculations based on SCF and SDCI studies of CaOH (Bauschlicher et al., 1984 and 1986) give mu values of 0.98, 0.49, and 0.11 D for the X, A, and B states, respectively, in good agreement with experiments in which the pure rotational spectra of these states were not detected. Modified Rittner (1951) and ligand-field models of these states are explored in detail, and the applicability of these results to observational searches for CaOH in circumstellar envelopes is indicated.
18. Toward verification of electroweak baryogenesis by electric dipole moments
NASA Astrophysics Data System (ADS)
Fuyuto, Kaori; Hisano, Junji; Senaha, Eibun
2016-04-01
We study general aspects of the CP-violating effects on the baryon asymmetry of the Universe (BAU) and electric dipole moments (EDMs) in models extended by an extra Higgs doublet and a singlet, together with electroweak-interacting fermions. In particular, the emphasis is on the structure of the CP-violating interactions and dependences of the BAU and EDMs on masses of the relevant particles. In a concrete mode, we investigate a relationship between the BAU and the electron EDM for a typical parameter set. As long as the BAU-related CP violation predominantly exists, the electron EDM has a strong power in probing electroweak baryogenesis. However, once a BAU-unrelated CP violation comes into play, the direct correlation between the BAU and electron EDM can be lost. Even in such a case, we point out that verifiability of the scenario still remains with the help of Higgs physics.
19. New Upper Limit on the Electron's Electric Dipole Moment
NASA Astrophysics Data System (ADS)
Doyle, John
2015-04-01
The ACME collaboration has measured the electron's electric dipole moment (eEDM) to be de =(- 2 . 1 +/- 3 .7stat +/- 2 .5syst) ×10-29 e .cm. This corresponds to an upper limit of | de | < 8 . 7 × 10-29 e .cm with 90 percent confidence, which represents an order of magnitude improvement on the previous best limit. We describe our method of measuring the eEDM using a buffer gas cooled beam of thorium monoxide (ThO) and discuss our approach to finding and quantifying systematic effects. This results constrains T-violating physics at the TeV energy scale. This project is supported by NSF.
20. Correction of magnetization sextupole and decapole in a 5 centimeter bore SSC dipole using passive superconductor
SciTech Connect
Green, M.A.
1991-05-01
Higher multipoles due to magnetization of the superconductor in four and five centimeter bore Superconducting Super Collider (SSC) superconducting dipole magnets have been observed. The use of passive superconductor to correct out the magnetization sextupole has been demonstrated on two dipoles built by the Lawrence Berkeley Laboratory (LBL). This reports shows how passive correction can be applied to the five centimeter SSC dipoles to remove sextupole and decapole caused by magnetization of the dipole superconductor. Two passive superconductor corrector options will be presented. The change in magnetization sextupole and decapole due to flux creep decay of the superconductor during injection can be partially compensated for using the passive superconductor. 9 refs; 5 figs.
1. Different viewpoints of electric dipole electric dipole interaction in the calculation of the energy transfer rate of rare earth ions in insulators
NASA Astrophysics Data System (ADS)
Xia, S.; Chua, M.; Tanner, P. A.
2001-09-01
The physical mechanism of the electric dipole-electric dipole (ED-ED) interaction may be looked at from several viewpoints in the calculation of the ED-ED energy transfer rate of rare earth ions in insulators. In this article, we demonstrate the equivalence of the results calculated from taking the ED-ED interaction as an energy transfer operation, or as a correction operator to the zero-order wavefunction of the donor-acceptor system.
2. Analysis of Exploding Plasma Behavior in a Dipole Magnetic Field
NASA Astrophysics Data System (ADS)
Muranaka, Takanobu; Uchimura, Hideyuki; Nakashima, Hideki; Zakharov, Yuri P.; Nikitin, Sergey A.; Ponomarenko, Arnold G.
2001-02-01
Numerical analyses on plasma behaviors in a dipole magnetic field are performed using a three-dimensional (3D) hybrid code. Results are compared with the experimental data and magnetohydrodynamics (MHD) analysis. Dependence of plasma expansion on initial plasma energy and location are discussed by temporal evolutions of plasma position and magnetic field strength. An overall good agreement in the expansion behavior of plasmas among these results is found. The asymmetrical shape of the expanding plasma in the cross-field direction is also noticed, and the reason for this is discussed. For future engineering applications, these results will be useful in designing an optimal configuration of the magnetic thrust chamber for laser fusion rockets, and for studying the effective explosive methods for protecting the earth from collisions by asteroids or comets.
3. The electric dipole moment of magnesium deuteride, MgD
SciTech Connect
Steimle, Timothy C. Zhang, Ruohan; Wang, Hailing
2014-06-14
The (0,0) A{sup 2}Π–X {sup 2}Σ{sup +} band of a cold molecular beam sample of magnesium monodeuteride, MgD, has been recorded field-free and in the presence of a static electric field of up to 11 kV/cm. The lines associated with the lowest rotational levels are detected for the first time. The field-free spectrum was analyzed to produce an improved set of fine structure parameters for the A{sup 2}Π (v = 0) state. The observed electric field induced splittings and shifts were analyzed to produce permanent electric dipole moments, μ{sup -vector}{sub el} of 2.567(10)D and 1.31(8)D for A{sup 2}Π (v = 0) and X{sup 2}Σ{sup +}(v = 0) states, respectively. The recommended value for μ{sup -vector}{sub el}(X{sup 2}Σ{sup +} (v = 0)) for MgH, based upon the measured value for MgD, is 1.32(8)D.
4. Systematics in a measurement of the electron's electric dipole moment using trapped molecular ions
NASA Astrophysics Data System (ADS)
Grau, Matt; Cossel, Kevin; Cairncross, William; Gresh, Dan; Zhou, Yan; Ye, Jun; Cornell, Eric
2015-05-01
A precision measurement of the electron's electric dipole moment (EDM) has important implications for physics beyond the Standard Model. Trapped molecular ions offer high sensitivity in such an experiment because of the large effective electric fields and long coherence times that are possible. Our experiment uses Ramsey spectroscopy of HfF+ ions in a linear RF trap with rotating bias fields, achieving coherence times beyond 1 second for 1000 trapped ions. Compared to other electron EDM experiments that use molecular beams, we will be sensitive to a different class of systematic errors. In this work we investigate systematic errors arising from all fields involved in the experiment, including the trapping and polarizing electric fields, magnetic field gradients, and motional effects such as geometric phases. This work was supported by NIST and NSF.
5. Local electric dipole moments for periodic systems via density functional theory embedding
SciTech Connect
Luber, Sandra
2014-12-21
We describe a novel approach for the calculation of local electric dipole moments for periodic systems. Since the position operator is ill-defined in periodic systems, maximally localized Wannier functions based on the Berry-phase approach are usually employed for the evaluation of local contributions to the total electric dipole moment of the system. We propose an alternative approach: within a subsystem-density functional theory based embedding scheme, subset electric dipole moments are derived without any additional localization procedure, both for hybrid and non-hybrid exchange–correlation functionals. This opens the way to a computationally efficient evaluation of local electric dipole moments in (molecular) periodic systems as well as their rigorous splitting into atomic electric dipole moments. As examples, Infrared spectra of liquid ethylene carbonate and dimethyl carbonate are presented, which are commonly employed as solvents in Lithium ion batteries.
6. Fabrication and test results of a high field, Nb3Sn superconducting racetrack dipole magnet
SciTech Connect
Benjegerdes, R.; Bish, P.; Byford, D.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A.; Hafalia, R.; Hannaford, R.; Higley, H.; Jackson, A.; Lietzke, A.; Liggins, N.; McInturff, A.D.; O'Neill, J.; Palmerston, E.; Sabbi, G.; Scanlan, R.M.; Swanson, J.
2001-06-15
The LBNL Superconducting Magnet Program is extending accelerator magnet technology to the highest possible fields. A 1 meter long, racetrack dipole magnet, utilizing state-of-the-art Nb{sub 3}Sn superconductor, has been built and tested. A record dipole filed of 14.7 Tesla has been achieved. Relevant features of the final assembly and tested results are discussed.
7. Measurement of the Electron's Electric Dipole Moment in Thorium Monoxide
NASA Astrophysics Data System (ADS)
Baron, J.; Demille, D.; Doyle, J.; Gabrielse, G.; Hess, P.; Hutzler, N.; Oleary, B.; Panda, C.; Petrik, E.; Spaun, B.
2013-06-01
Some polar diatomic molecules have large effective internal electric fields ({E}_{eff}10^{11} V/cm that can be used to make measurements of the electron's electric dipole moment (eEDM) with unprecedented sensitivity. By performing precision spectroscopy on the metastable H ^{3}?_{1} state of ThO in a cryogenic buffer gas beam, we have demonstrated a statistical sensitivity to the eEDM of ? d_{e}?110^{-28} e\\cdot cm/?{T/{days}}, which is competitive with the current experimental limit, |d_{e}|<1.0510^{-27}e\\cdot cm. The existence of a non-zero eEDM on this level would be evidence for the existence of interactions that violate parity and time-reversal symmetries that are not included in the Standard Model. Many extensions to the Standard Model (in particular supersymmetric theories) predict the eEDM to be very close to the current experimental limit. We present an overview and discuss the characterization of systematic errors in this experiment. E. R. Meyer and J. L. Bohn, Phys. Rev. A 78, 010502 (2008) J. Hudson, D. Kara, J. Smallman, B. Sauer, M. Tarbutt, E. Hinds, Nature 473 493 (2011) This work is supported by the NSF.
8. Local spin dynamics with the electron electric dipole moment
NASA Astrophysics Data System (ADS)
Fukuda, Masahiro; Soga, Kota; Senami, Masato; Tachibana, Akitomo
2016-01-01
The local spin dynamics of the electron is studied from the viewpoint of the electric dipole moment (EDM) of the electron in the framework of the quantum field theory. The improvements of the computational accuracy of the effective electric field (Eeff) for the EDM and the understanding of spin precession are important for the experimental determination of the upper bound of the EDM. Calculations of Eeff in YbF (2Σ1 /2 ), BaF (2Σ1 /2 ), ThO (3Δ1 ), and HF+ (2Π1 /2 ) are performed on the basis of the restricted active space configuration interaction approach by using the four-component relativistic electronic structure calculation. The spin precession is also discussed from the viewpoint of local spin torque dynamics. We show that a contribution to the torque density for the spin is brought into by the EDM. Distributions of the local spin angular momentum density and torque densities induced by external fields in the above molecules are calculated and a property related with large Eeff is discussed.
9. Coil end design for the LHC dipole magnet
SciTech Connect
Brandt, J.S.
1996-05-21
This paper describes the design of the coil ends for the Large Hadron Collider dipole magnets of the CERN European Laboratory for Particle Physics in Switzerland. This alternative to existing European designs was provided by Fermi National Accelerator Laboratory by agreement between CERN and the United States. The superconducting cable paths are determined from both magnetic and mechanical considerations. The coil end parts used to shape and constrain the conductors in the coil ends are designed using the developable surface, grouped end approach. This method allows the analysis of strain energy within the conductor groups, and the optimization of mechanical factors during the design. Design intent and implementation are discussed. Inner and outer coil design challenges and end analysis are detailed.
10. Spectrometer sensitivity calibration in the extreme uv by means of branching ratios of magnetic dipole lines
SciTech Connect
Denne, B.; Hinnov, E.
1984-04-01
Relative intensity measurements of various line pairs resulting from magnetic dipole transitions within the configurations s/sup 2/p/sup 2/ and s/sup 2/p/sup 4/, in conjunction with calculated transition probabilities, have been used to determine the wavelength dependence of the sensitivity of a grazing incidence spectrometer, in the range 400 to 1000 A. Emissions from Cr XIX, Fe XXI, Ni XXI and XXIII, Cu XXIV, and Zr XXVII ions in PLT tokamak discharges were used for this purpose. Absolute sensitivity of the spectrometer at selected wavelengths had been determined by the traditional hydrogen, helium, carbon, and oxygen electric-dipole line pairs from the same discharges. Similar attempts to use transitions in the s/sup 2/p/sup 3/ configurations in Cr XVIII, Zr XXVI, and Mo XXVIII ions resulted in significant discrepancies that are ascribed to uncertainties in the corresponding calculated transition probabilities.
11. Communication: Theoretical study of ThO for the electron electric dipole moment search
SciTech Connect
Skripnikov, L. V. Petrov, A. N.; Titov, A. V.; Department of Physics, Saint Petersburg State University, Saint Petersburg, Petrodvoretz 198904
2013-12-14
An experiment to search for the electron electric dipole moment (eEDM) on the metastable H{sup 3}?{sub 1} state of ThO molecule was proposed and now prepared by the ACME Collaboration [ http://www.electronedm.org ]. To interpret the experiment in terms of eEDM and dimensionless constant k{sub T,} {sub P} characterizing the strength of the T,P-odd pseudoscalarscalar electronnucleus neutral current interaction, an accurate theoretical study of an effective electric field on electron, E{sub eff}, and a parameter of the T,P-odd pseudoscalarscalar interaction, W{sub T,} {sub P}, in ThO is required. We report our results for E{sub eff} (84 GV/cm) and W{sub T,} {sub P} (116 kHz) together with the hyperfine structure constant, molecule frame dipole moment, and H{sup 3}?{sub 1} ? X{sup 1}?{sup +} transition energy, which can serve as a measure of reliability of the obtained E{sub eff} and W{sub T,} {sub P} values. Besides, our results include a parity assignment and evaluation of the electric-field dependence for the magnetic g factors in the ?-doublets of H{sup 3}?{sub 1}.
12. Magnetic properties of iron yoke laminations for SSC dipole magnets
SciTech Connect
Kahn, S.A.; Morgan, G.H.
1991-01-01
We examine the magnetic properties for the iron used in the SSC yoke laminations so that the accelerator tolerances can be met. The accelerator requirements for field quality specify a tolerance on the variation in the central field. At machine injection the variation in field is attributed to coercivity, H{sub c}. Requirements on the magnitude and the variation of H{sub c} are presented. At the 6.65 tesla operating field the variation in the saturation magnetization dominates the magnetic tolerance for the iron. 4 refs., 3 figs., 2 tabs.
13. Nonadiabatic behavior of the magnetic moment of a charged particle in a dipole magnetic field
NASA Technical Reports Server (NTRS)
Murakami, Sadayoshi; Sato, Tetsuya; Hasegawa, Akira
1990-01-01
This paper investigates the dynamic behavior of the magnetic moment of a particle confined in a magnetic dipole field in the presence of a low-frequency electrostatic wave. It is shown that there exist two kinds of resonances (the bounce-E x B drift resonance and the wave-drift resonance) by which the adiabaticity of the magnetic moment is broken. The unstable conditions obtained by theoretical considerations showed good agreement with the numerical results.
14. First Atomic Electric Dipole Moment Limit Derived from an Octupole-Deformed Nucleus
NASA Astrophysics Data System (ADS)
Parker, Richard; Bishof, Michael; Kalita, Mukut; Lemke, Nathan; Dietrich, Matt; Bailey, Kevin; Greene, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Mueller, Peter; O'Connor, T. P.; Singh, Jaideep
2015-05-01
Ra-225 (half-life = 15 d, nuclear spin = 1/2) is a promising isotope for a measurement of the EDM of a diamagnetic atom. Due to its large nuclear octupole deformation and high atomic mass, the EDM sensitivity of Ra-225 is expected to be 2-3 orders of magnitude larger than that of Hg-199. We demonstrate an efficient multiple-stage apparatus in which radium atoms are first loaded into a MOT, then transferred into a movable optical-dipole trap (ODT) that carries the atoms over 1 m to a magnetically-shielded science chamber, loaded into a standing-wave ODT, polarized, and then allowed to precess in magnetic and electric fields. We will discuss our first measurement of the EDM of Ra-225, as well as plans for future improvements. This work is supported by DOE, Office of Nuclear Physics (DE-AC02-06CH11357).
15. Search for Electric dipole moment (EDM) in laser cooled and trapped 225Ra atoms
NASA Astrophysics Data System (ADS)
Kalita, Mukut; Bailey, Kevin; Dietrich, Matthew; Green, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Lemke, Nathan; Mueller, Peter; O'Connor, Tom; Parker, Richard; Singh, Jaideep; Trimble, Will; Argonne National Laboratory Collaboration; University Of Chicago Collabration; University Of Kentucky Collaboration
2014-05-01
We are searching for an EDM of the diamagnetic 225Ra atom. 225Ra has nuclear spin I =1/2. Experimental sensitivity to its EDM is enhanced due to its heavy mass and the increased Schiff moment of its octupole deformed nucleus. Our experiment involves collecting laser cooled Ra atoms in a magneto-optical trap (MOT), transporting them 1 meter with a far off-resonant optical dipole trap (ODT) and then transferring the atoms to a second standing-wave ODT in our experimental chamber. We will report our recent experiences in polarizing and observing Larmor precession of 225Ra atoms in parallel electric and magnetic fields in a magnetically shielded region and progress towards a first measurement of the EDM of 225Ra. This work is supported by DOE, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357 and contract No. DE-FG02-99ER41101.
16. Temporal behaviour of multipole components of the magnetic field in a small dipole magnet wound with coated conductors
NASA Astrophysics Data System (ADS)
Amemiya, Naoyuki; Otake, Hiroaki; Sano, Takuya; Nakamura, Taketsune; Ogitsu, Toru; Koyanagi, Kei; Kurusu, Tsutomu
2015-03-01
To study the influence of coated-conductor magnetization on the field quality of accelerator magnets, we made a small dipole magnet consisting of four racetrack coils wound with GdBCO coated conductors and measured its magnetic field in liquid nitrogen by using rotating pick-up coils. We focused on the dipole and sextupole components (coefficients) of the magnetic field, which vary with time owing to the decay of the magnetization of the coated conductors. About 50 min (3055 s) after the current was ramped up to 50 A, the dipole coefficient normalized by the design value of the dipole component, i.e., the value calculated with the designed coil shape and the uniform current distribution in the coated conductors, increased by 7.4 10-4, and the sextupole coefficient normalized by the design value of the dipole component increased by 1.8 10-4. The magnitudes of the dipole and sextupole components depended on the excitation history of the magnet. Electromagnetic field analyses were carried out to calculate the current distributions in coated conductors, considering their superconducting properties; the dipole and sextupole coefficients were then determined from the calculated current distributions. Although the analyses were based on the two-dimensional approximation of the cross-section of the magnet, the temporal behaviours as well as the hysteretic characteristics of the calculated dipole and sextupole coefficients agree qualitatively with those of the dipole and sextupole coefficients measured in the magnet.
17. Frequency shifts of an electric-dipole resonance near a conducting surface
NASA Technical Reports Server (NTRS)
Holland, W. R.; Hall, D. G.
1984-01-01
The resonance frequency of an electric dipole placed near a conducting surface is shifted by the dipole-surface interaction. The observation and measurement of these shifts at optical frequencies is reported for an experimental system that consists of a metal-island film spaced a distance d from a continuous Ag film. The dependence of the shift in the frequency of the island resonance on d shows good agreement with that predicted by a classical theory of the dipole-surface interaction.
18. Neutron Electric Dipole Moment and Tensor Charges from Lattice QCD.
PubMed
Bhattacharya, Tanmoy; Cirigliano, Vincenzo; Gupta, Rajan; Lin, Huey-Wen; Yoon, Boram
2015-11-20
We present lattice QCD results on the neutron tensor charges including, for the first time, a simultaneous extrapolation in the lattice spacing, volume, and light quark masses to the physical point in the continuum limit. We find that the "disconnected" contribution is smaller than the statistical error in the "connected" contribution. Our estimates in the modified minimal subtraction scheme at 2 GeV, including all systematics, are g_{T}^{d-u}=1.020(76), g_{T}^{d}=0.774(66), g_{T}^{u}=-0.233(28), and g_{T}^{s}=0.008(9). The flavor diagonal charges determine the size of the neutron electric dipole moment (EDM) induced by quark EDMs that are generated in many new scenarios of CP violation beyond the standard model. We use our results to derive model-independent bounds on the EDMs of light quarks and update the EDM phenomenology in split supersymmetry with gaugino mass unification, finding a stringent upper bound of d_{n}<4×10^{-28} e cm for the neutron EDM in this scenario. PMID:26636847
19. CP-odd phase correlations and electric dipole moments
SciTech Connect
Olive, Keith A.; Pospelov, Maxim; Ritz, Adam; Santoso, Yudi
2005-10-01
We revisit the constraints imposed by electric dipole moments (EDMs) of nucleons and heavy atoms on new CP-violating sources within supersymmetric theories. We point out that certain two-loop renormalization group corrections induce significant mixing between the basis-invariant CP-odd phases. In the framework of the constrained minimal supersymmetric standard model, the CP-odd invariant related to the soft trilinear A-phase at the grand unified theory (GUT) scale, {theta}{sub A}, induces nontrivial and distinct CP-odd phases for the three gaugino masses at the weak scale. The latter give one-loop contributions to EDMs enhanced by tan{beta}, and can provide the dominant contribution to the electron EDM induced by {theta}{sub A}. We perform a detailed analysis of the EDM constraints within the constrained minimal supersymmetric standard model, exhibiting the reach, in terms of sparticle spectra, which may be obtained assuming generic phases, as well as the limits on the CP-odd phases for some specific parameter points where detailed phenomenological studies are available. We also illustrate how this reach will expand with results from the next generation of experiments which are currently in development.
20. Atomic electric dipole moments: The Schiff theorem and its corrections
SciTech Connect
Liu, C.-P.; Ramsey-Musolf, M. J.; Haxton, W. C.; Timmermans, R. G. E.; Dieperink, A. E. L.
2007-09-15
Searches for the permanent electric dipole moments (EDMs) of diamagnetic atoms provide powerful probes of CP-violating hadronic and semileptonic interactions. The theoretical interpretation of such experiments, however, requires careful implementation of a well-known theorem by Schiff that implies a vanishing net EDM for an atom built entirely from pointlike, nonrelativistic constituents that interact only electrostatically. Any experimental observation of a nonzero atomic EDM would result from corrections to the pointlike, nonrelativistic, electrostatic assumption. We reformulate Schiff's theorem at the operator level and delineate the electronic and nuclear operators whose atomic matrix elements generate corrections to 'Schiff screening'. We obtain a form for the operator responsible for the leading correction associated with finite nuclear size - the so-called Schiff moment operator - and observe that it differs from the corresponding operator used in previous Schiff moment computations. We show that the more general Schiff moment operator reduces to the previously employed operator only under certain approximations that are not generally justified. We also identify other corrections to Schiff screening that may not be included properly in previous theoretical treatments. We discuss practical considerations for obtaining a complete computation of corrections to Schiff screening in atomic EDM calculations.
1. Model dependence of the {sup 2}H electric dipole moment
SciTech Connect
Afnan, I. R.; Gibson, B. F.
2010-12-15
Background: Direct measurement of the electric dipole moment (EDM) of the neutron is in the future; measurement of a nuclear EDM may well come first. The deuteron is one nucleus for which exact model calculations are feasible. Purpose: We explore the model dependence of deuteron EDM calculations. Methods: Using a separable potential formulation of the Hamiltonian, we examine the sensitivity of the deuteron EDM to variation in the nucleon-nucleon interaction. We write the EDM as the sum of two terms, the first depending on the target wave function with plane-wave intermediate states, and the second depending on intermediate multiple scattering in the {sup 3}P{sub 1} channel, the latter being sensitive to the off-shell behavior of the {sup 3}P{sub 1} amplitude. Results: We compare the full calculation with the plane-wave approximation result, examine the tensor force contribution to the model results, and explore the effect of short-range repulsion found in realistic, contemporary potential models of the deuteron. Conclusions: Because one-pion exchange dominates the EDM calculation, separable potential model calculations will provide an adequate description of the {sup 2}H EDM until such time as a measurement better than 10% is obtained.
2. Neutron electric dipole moment in the gauge-Higgs unification
SciTech Connect
Adachi, Yuki; Lim, C. S.; Maru, Nobuhito
2009-09-01
We study the neutron electric dipole moment (EDM) in a five-dimensional SU(3) gauge-Higgs unification compactified on M{sup 4}xS{sup 1}/Z{sub 2} space-time including a massive fermion. We point out that to realize the CP violation is a nontrivial task in the gauge-Higgs unification scenario and argue how the CP symmetry is broken spontaneously by the vacuum expectation value of the Higgs, the extra space component of the gauge field. We emphasize the importance of the interplay between the vacuum expectation value of the Higgs and the Z{sub 2}-odd bulk mass term to get physically the CP violation. We then calculate the one-loop contributions to the neutron EDM as the typical example of the CP violating observable and find that the EDM appears already at the one-loop level, without invoking the three-generation scheme. We then derive a lower bound for the compactification scale, which is around 2.6 TeV, by comparing the contribution due to the nonzero Kaluza-Klein modes with the experimental data.
3. Neutron Electric Dipole Moment and Tensor Charges from Lattice QCD
NASA Astrophysics Data System (ADS)
Bhattacharya, Tanmoy; Cirigliano, Vincenzo; Gupta, Rajan; Lin, Huey-Wen; Yoon, Boram; Pndme Collaboration
2015-11-01
We present lattice QCD results on the neutron tensor charges including, for the first time, a simultaneous extrapolation in the lattice spacing, volume, and light quark masses to the physical point in the continuum limit. We find that the "disconnected" contribution is smaller than the statistical error in the "connected" contribution. Our estimates in the modified minimal subtraction scheme at 2 GeV, including all systematics, are gTd -u=1.020 (76 ), gTd=0.774 (66 ), gTu=-0.233 (28 ), and gTs=0.008 (9 ). The flavor diagonal charges determine the size of the neutron electric dipole moment (EDM) induced by quark EDMs that are generated in many new scenarios of C P violation beyond the standard model. We use our results to derive model-independent bounds on the EDMs of light quarks and update the EDM phenomenology in split supersymmetry with gaugino mass unification, finding a stringent upper bound of dn<4 ×1 0-28 e cm for the neutron EDM in this scenario.
4. Atomic electric dipole moments: The Schiff theorem and its corrections
NASA Astrophysics Data System (ADS)
Liu, C.-P.; Ramsey-Musolf, M. J.; Haxton, W. C.; Timmermans, R. G. E.; Dieperink, A. E. L.
2007-09-01
Searches for the permanent electric dipole moments (EDMs) of diamagnetic atoms provide powerful probes of CP-violating hadronic and semileptonic interactions. The theoretical interpretation of such experiments, however, requires careful implementation of a well-known theorem by Schiff that implies a vanishing net EDM for an atom built entirely from pointlike, nonrelativistic constituents that interact only electrostatically. Any experimental observation of a nonzero atomic EDM would result from corrections to the pointlike, nonrelativistic, electrostatic assumption. We reformulate Schiff's theorem at the operator level and delineate the electronic and nuclear operators whose atomic matrix elements generate corrections to “Schiff screening.” We obtain a form for the operator responsible for the leading correction associated with finite nuclear size—the so-called Schiff moment operator—and observe that it differs from the corresponding operator used in previous Schiff moment computations. We show that the more general Schiff moment operator reduces to the previously employed operator only under certain approximations that are not generally justified. We also identify other corrections to Schiff screening that may not be included properly in previous theoretical treatments. We discuss practical considerations for obtaining a complete computation of corrections to Schiff screening in atomic EDM calculations.
5. MAGNETIC MODELING VS MEASUREMENTS OF THE DIPOLES FOR THE JLAB 10 KW FREE ELECTRON LASER UPGRADE
SciTech Connect
David Douglas; Robin Wines; Tom Hiatt; George Biallas; Kenneth Baggett; T.J. Schultheiss; V.A. Christina; J.W. Rathke; A. Smirnov; D. Newsham; Y. Luo; D. Yu
2003-05-01
Magnetic measurements of the six families of dipoles for the infrared Free Electron Laser Upgrade at the Thomas Jefferson National Accelerator Facility (Jlab) are compared to the magnetic models on which their design is based. The magnets were designed in parallel by three organizations. They used ANSYS, Radia or Opera 3D as a 3D magnetic modeling program. Comparison of the discrepancies between model and magnet measurement is presented along with analysis of their potential causes. These dipoles operate in two field ranges. The Injector/ Extractor Dipoles operate around 0.05 T and the Arc Dipoles and Optical Chicane Dipoles operate between 0.22 to 0.71 T. All magnets are required to meet core field and field integral flatness to parts in 104 over their good field region.
6. Nb/sub 3/Sn dipole magnet reacted after winding
SciTech Connect
Taylor, C.; Scanlan, R.; Peters, C.; Wolgast, R.; Gilbert, W.; Hassenzahl, W.; Meuser, R.; Rechen, J.
1984-09-01
A 5 cm bore dia., 1-m-long dipole model magnet was constructed by winding un-reacted cable, followed by reaction and epoxy-impregnation. Experience and test results are described on the 1.7 mm dia. internal-tin wire, the eleven-strand flattened cable, fiberglass insulation, and construction of the magnet. Each half of the magnet has two double-pancake-type windings that were reacted in a single operation. The two double-pancakes were then separately vacuum impregnated after soldering the flexible Nb-Ti leads to the Nb/sub 3/Sn conductors. No iron flux return yoke was used. In initial tests a central field of 8.0 T was reached at 4.4 K. However, evidence from training behavior, and 1.8 K tests indicate that premature quenching, rather than critical current of the cable, limited the field intensity. The magnet was reassembled and more rigidly clamped; additional test results are reported.
7. Electric dipolar Kondo effect emerging from a vibrating magnetic ion.
PubMed
Hotta, Takashi; Ueda, Kazuo
2012-06-15
When a magnetic ion vibrates in a metal, it inevitably introduces a new channel of hybridization with conduction electrons, and in general, the vibrating ion induces an electric dipole moment. In such a situation, we find that magnetic and nonmagnetic Kondo effects alternatively occur due to the screening of the spin moment and electric dipole moment of the vibrating ion. In particular, the electric dipolar two-channel Kondo effect is found to occur for a weak Coulomb interaction. We also show that a magnetically robust heavy-electron state appears near the fixed point of the electric dipolar two-channel Kondo effect. We believe that the vibrating magnetic ion opens a new door in Kondo physics. PMID:23004326
8. Ramp-rate sensitivity of SSC dipole magnet prototypes
SciTech Connect
Devred, A.; Ogitsu, T.
1994-07-01
One of the major achievements of the magnet R&D program for the Superconducting Super Collider (SSC) is the fabrication and test of a series of 20 5-cm aperture, 15-m long dipole magnet prototypes. The ramp rate sensitivity of these magnets appears to fall in at least two categories that can be correlated to the manufacturer and production batch of the strands used for the inner-coil cables. The first category, referred to as type-A, is characterized by a strong quench current degradation at high ramp rates, usually accompanied by large distortions of the multipole fields and large energy losses. The second category, referred to as type-B, is characterized by a sudden drop of quench current at low ramp rates, followed by a much milder degradation at larger rates. The multipole fields of the type-B magnets show little ramp-rate sensitivity, and the energy losses are smaller than for the type-A magnets. The behavior of the Type-A magnets can be explained in terms of inter-strand eddy currents arising from low and non-uniform resistances at the crossovers between the strands of the two-layer Rutherford-type cable. Anomalies in the transport-current repartition among the cable strands are suggested as a possible cause for the type-B behavior. The origins of these anomalies have not yet been clearly identified. The SSC project was canceled by decision of the United States Congress on October 21, 1994.
9. Nucleon electric dipole moment with the gradient flow: The ? -term contribution
NASA Astrophysics Data System (ADS)
Shindler, Andrea; Luu, Thomas; de Vries, Jordy
2015-11-01
We propose a new method to calculate electric dipole moments induced by the strong QCD ? term. The method is based on the gradient flow for gauge fields and is free from renormalization ambiguities. We test our method by computing the nucleon electric dipole moments in pure Yang-Mills theory at several lattice spacings, enabling a first-of-its-kind continuum extrapolation. The method is rather general and can be applied for any quantity computed in a ? vacuum. This first application of the gradient flow has been successful and demonstrates proof-of-principle, thereby providing a novel method to obtain precise results for nucleon and light nuclear electric dipole moments.
10. Contamination of dark matter experiments from atmospheric magnetic dipoles
NASA Astrophysics Data System (ADS)
Bueno, A.; Masip, M.; Sánchez-Lucas, P.; Setzer, N.
2013-10-01
Dark matter collisions with heavy nuclei (Xe, Ge, Si, Na) may produce recoils observable at direct-search experiments. Given that some of these experiments are yielding conflicting information, however, it is worth asking if physics other than dark matter may produce similar nuclear recoils. We examine under what conditions an atmospherically produced neutral particle with a relatively large magnetic dipole moment could fake a dark matter signal. We argue that a very definite flux could explain the signals seen at DAMA/LIBRA, CDMS/Si and CoGeNT consistently with the bounds from XENON100 and CDMS/Ge. To explore the plausibility of this scenario, we discuss a concrete model with 10-50 MeV sterile neutrinos that was recently proposed to explain the LSND and MiniBooNE anomalies.
11. Challenges and opportunities in the search for electric dipole moment (EDM) in 225Ra atom
NASA Astrophysics Data System (ADS)
Kalita, Mukut; Bailey, Kevin; Dietrich, Matthew; Greene, John; Holt, Roy; Korsch, Wolfgang; Lu, Zheng-Tian; Mueller, Peter; O'Connor, Thomas; Parker, Richard; Sulai, Ibrahim; Singh, Jaideep
2011-10-01
The observation of a permanent electric dipole moment (EDM) in a non-degenerate system would indicate violation of time reversal symmetry. 225Ra atom is a particularly attractive candidate for this search since it has a nuclear spin I = 1/2 and has a significant nuclear octupole deformation. This property increases the Schiff moment of the nucleus and therefore enhances the atomic EDM. The half life (t1/2 = 14.9 days) of 225Ra is sufficiently long to perform EDM searches. Our group has already demonstrated the trapping of laser cooled Ra atoms in a magneto-optical trap (MOT) and transferring them to a far off resonant optical dipole trap (ODT). We will discuss our recent progress on manipulation of ultra cold Ra atoms in the ODT, efforts in improving our laser systems and generation of electric and magnetic fields required for the measurement. This work is supported by DOE, Office of Nuclear Physics, under contract No. DE-AC02-06CH11357 and contract No. DE-FG02-99ER41101.
12. Investigation of a new magnetic dipole mode in the heavy, deformed nuclei 154 Sm, 156 Gd, 158 Gd, 164 Dy, 168 Er, and 174 Yb with high resolution electron scattering
NASA Astrophysics Data System (ADS)
Bohle, Detlev
A magnetic dipole mode in heavy, deformed nuclei is demonstrated using inelastic electron scattering with high energy resolution. The nuclei were investigated in an electron linear accelerator; additional measurements with inelastically scattered protons were conducted in a synchrocyclotron. A collective, magnetic dipole excitation is discovered in all nuclei, and characterized as an orbit mode. The measurements on 156 Gd show strong fragmentation of the magnetic dipole strength. The experimental results were explained using three models: the two-rotor model, the random phase approximation, and the interacting boson approximation. In a macroscopic picture, the models reveal the discovered mode as a magnetic analogy of the electric dipole resonance.
13. ANALYTICAL CALCULATION OF STOKES PROFILES OF ROTATING STELLAR MAGNETIC DIPOLE
SciTech Connect
Martinez Gonzalez, M. J.
2012-08-20
The observation of the polarization emerging from a rotating star at different phases opens up the possibility to map the magnetic field in the stellar surface thanks to the well-known Zeeman-Doppler imaging. When the magnetic field is sufficiently weak, the circular and linear polarization profiles locally in each point of the star are proportional to the first and second derivatives of the unperturbed intensity profile, respectively. We show that the weak-field approximation (for weak lines in the case of linear polarization) can be generalized to the case of a rotating star including the Doppler effect and taking into account the integration on the stellar surface. The Stokes profiles are written as a linear combination of wavelength-dependent terms expressed as series expansions in terms of Hermite polynomials. These terms contain the surface-integrated magnetic field and velocity components. The direct numerical evaluation of these quantities is limited to rotation velocities not larger than eight times the Doppler width of the local absorption profiles. Additionally, we demonstrate that in a rotating star, the circular polarization flux depends on the derivative of the intensity flux with respect to the wavelength and also on the profile itself. Likewise, the linear polarization depends on the profile and on its first and second derivatives with respect to the wavelength. We particularize the general expressions to a rotating dipole.
14. Neptune radio emission in dipole and multipole magnetic fields
NASA Technical Reports Server (NTRS)
Sawyer, C. B.; King, N. V.; Romig, J. H.; Warwick, J. W.
1995-01-01
We study Neptune's smooth radio emission in two ways: we simulate the observations and we then consider the radio effects of Neptune's magnetic multipoles. A procedure to deduce the characteristics of radio sources observed by the Planetary Radio Astronomy experiment minimizes limiting assumptions and maximizes use of the data, including quantitative measurement of circular polarization. Study of specific sources simulates time variation of intensity and apparent polarization of their integrated emission over an extended time period. The method is applied to Neptune smooth recurrent emission (SRE). Time series are modeled with both broad and beamed emission patterns, and at two frequencies which exhibit different time variation of polarization. These dipole-based results are overturned by consideration of more complex models of Neptune's magnetic field. Any smooth emission from the anticipated auroral radio source is weak and briefly observed. Dominant SRE originates complex fields at midlatitude. Possible SRE source locations overlap that of 'high-latitude' emission (HLE) between +(out) and -(in) quadrupoles. This is the first identification of multipolar magnetic structure with a major source of planetary radio emission.
15. Low-energy electric dipole response of Sn isotopes
NASA Astrophysics Data System (ADS)
Papakonstantinou, P.; Hergert, H.; Ponomarev, V. Yu.; Roth, R.
2014-03-01
We study the low-energy dipole (LED) strength distribution along the Sn isotopic chain in both the isoscalar (IS) and the isovector (IV, or E1) electric channels, to provide testable predictions and guidance for new experiments with stable targets and radioactive beams. We use the self-consistent quasi-particle random-phase approximation (QRPA) with finite-range interactions and mainly the Gogny D1S force. We analyze also the performance of a realistic two-body interaction supplemented by a phenomenological three-body contact term. We find that from N =50 and up to the N =82 shell closure (132Sn) the lowest-energy part of the IS-LED spectrum is dominated by a collective transition whose properties vary smoothly with neutron number and which cannot be interpreted as a neutron-skin oscillation. For the neutron-rich species this state contributes to the E1 strength below particle threshold, but much more E1 strength is carried by other, weak but numerous transitions around or above threshold. We find that strong structural changes in the spectrum take effect beyond N =82, namely increased LED strength and lower excitation energies. Our results with the Gogny interaction are compatible with existing data. On this basis we predict that (a) the summed IS strength below particle threshold shall be of the same order of magnitude for N =50-82, (b) the summed E1 strength up to approximately 12 MeV shall be similar for N =50-82 MeV, while (c) the summed E1 strength below threshold shall be of the same order of magnitude for N ≈64-82 and much weaker for the lighter, more-symmetric isotopes. We point out a general agreement of our results with other nonrelativistic studies, the absence of a collective IS mode in some of those studies, and a possibly radical disagreement with relativistic models.
16. Theoretical prediction and impact of fundamental electric dipole moments
NASA Astrophysics Data System (ADS)
Ellis, Sebastian A. R.; Kane, Gordon L.
2016-01-01
The predicted Standard Model (SM) electric dipole moments (EDMs) of electrons and quarks are tiny, providing an important window to observe new physics. Theories beyond the SM typically allow relatively large EDMs. The EDMs depend on the relative phases of terms in the effective Lagrangian of the extended theory, which are generally unknown. Underlying theories, such as string/M-theories compactified to four dimensions, could predict the phases and thus EDMs in the resulting supersymmetric (SUSY) theory. Earlier one of us, with collaborators, made such a prediction and found, unexpectedly, that the phases were predicted to be zero at tree level in the theory at the unification or string scale ˜ O(1016 GeV). Electroweak (EW) scale EDMs still arise via running from the high scale, and depend only on the SM Yukawa couplings that also give the CKM phase. Here we extend the earlier work by studying the dependence of the low scale EDMs on the constrained but not fully known fundamental Yukawa couplings. The dominant contribution is from two loop diagrams and is not sensitive to the choice of Yukawa texture. The electron EDM should not be found to be larger than about 5 × 10-30 e cm, and the neutron EDM should not be larger than about 5 × 10-29 e cm. These values are quite a bit smaller than the reported predictions from Split SUSY and typical effective theories, but much larger than the Standard Model prediction. Also, since models with random phases typically give much larger EDMs, it is a significant testable prediction of compactified M-theory that the EDMs should not be above these upper limits. The actual EDMs can be below the limits, so once they are measured they could provide new insight into the fundamental Yukawa couplings of leptons and quarks. We comment also on the role of strong CP violation. EDMs probe fundamental physics near the Planck scale.
17. Magnetic field measurements of 1. 5 meter model SSC collider dipole magnets at Fermilab
SciTech Connect
Lamm, M.J.; Bleadon, M.; Coulter, K.J.; Delchamps, S.; Hanft, R.; Jaffery, T.S.; Kinney, W.; Koska, W.; Ozelis, J.P.; Strait, J.; Wake, M. ); DiMarco, J. )
1991-09-01
Magnetic field measurements have been performed at Fermilab on 1.5 m magnetic length model dipoles for the Superconducting Supercollider. Harmonic measurements are recorded at room temperature before and after the collared coil is assembled into the yoke and at liquid helium temperature. Measurements are made as a function of longitudinal position and excitation current. High field data are compared with room temperature measurements of both the collared coil and the completed yoked magnet and with the predicted fields for both the body of the magnet and the coil ends.
18. Theory for electric dipole superconductivity with an application for bilayer excitons
PubMed Central
Jiang, Qing-Dong; Bao, Zhi-qiang; Sun, Qing-Feng; Xie, X. C.
2015-01-01
Exciton superfluid is a macroscopic quantum phenomenon in which large quantities of excitons undergo the Bose-Einstein condensation. Recently, exciton superfluid has been widely studied in various bilayer systems. However, experimental measurements only provide indirect evidence for the existence of exciton superfluid. In this article, by viewing the exciton in a bilayer system as an electric dipole, we derive the London-type and Ginzburg-Landau-type equations for the electric dipole superconductors. By using these equations, we discover the Meissner-type effect and the electric dipole current Josephson effect. These effects can provide direct evidence for the formation of the exciton superfluid state in bilayer systems and pave new ways to drive an electric dipole current. PMID:26154838
19. Charged Lepton Electric Dipole Moment Enhancement in the Lorentz Violated Extension of the Standard Model
NASA Astrophysics Data System (ADS)
Haghighat, M.; Motie, I.; Rezaei, Z.
2013-08-01
We consider the Lorentz violated extension of the standard model. In this framework, there are terms that explicitly violate CP-symmetry. We examine the CPT-even dμν-term to find the electric dipole moment of charged leptons. We show that the form factors besides the momentum transfer, depend on a new Lorentz-scalar, constructing by dμν and the four momenta of the lepton, as well. Such an energy dependence of the electric dipole form factor leads to an enhancement of the lepton electric dipole moment at high energy, even at the zero momentum transfer. We show that at {\\vert}d/{\\vert}p2{m^2l ˜ 1 the electric dipole moment of the charged lepton can be as large as 10-14e cm.
20. CryoEDM: A cryogenic experiment to measure the neutron electric dipole moment
NASA Astrophysics Data System (ADS)
van der Grinten, M. G. D.; CryoEDM Collaboration; Balashov, S. N.; Francis, V.; Green, K.; Iaydjiev, P. S.; Ivanov, S. N.; Khazov, A.; Tucker, M. A. H.; Wark, D. L.; Davidson, A.; Hardiman, M.; Harris, P. G.; Katsika, K.; Pendlebury, J. M.; Peeters, S. J. M.; Shiers, D. B.; Smith, P.; Townsley, C.; Wardell, I.; Clarke, C.; Henry, S.; Kraus, H.; McCann, M.; Geltenbort, P.; Yoshiki, Y.
2009-12-01
CryoEDM is an experiment that aims to measure the electric dipole moment (EDM) of the neutron to a precision of 10 -28 e cm. A description of CryoEDM, the apparatus, technologies and commissioning is presented.
1. Electric and Magnetic Field Detection in Elasmobranch Fishes
NASA Astrophysics Data System (ADS)
1982-11-01
Sharks, skates, and rays receive electrical information about the positions of their prey, the drift of ocean currents, and their magnetic compass headings. At sea, dogfish and blue sharks were observed to execute apparent feeding responses to dipole electric fields designed to mimic prey. In training experiments, stingrays showed the ability to orient relative to uniform electric fields similar to those produced by ocean currents. Voltage gradients of only 5 nanovolts per centimeter would elicit either behavior.
2. Progress Towards a New Measurement of the Electric Dipole Moment of ^199Hg.
NASA Astrophysics Data System (ADS)
Swallows, M. D.; Griffith, W. C.; Heckel, B. R.; Fortson, E. N.; Romalis, M. V.
2007-06-01
We are currently undertaking a four vapor cell search for the permanent electric dipole moment (EDM) of ^199Hg. The existence of a nonzero EDM would imply a source of CP violation beyond the standard model. The present limit on the EDM of ^199 Hg is |dHg| < 2.1 x10-28 ,,, which was established several years ago by our group at the University of Washington. In that experiment, two quartz vapor cells containing polarized Hg vapor were placed in parallel magnetic and anti-parallel electric fields (the use of two cells permitted the removal of common-mode effects), and the spin precession frequency was measured using an optical technique. In our current experiment, two additional cells at zero electric field serve to cancel magnetic gradient noise and to improve limits on systematic effects due to charging and leakage currents. We have recently overcome several systematic issues and begun acquiring data with our upgraded apparatus. To prevent experimenter bias from influencing the data, we have also instituted a blind analysis protocol. The statistical error of the data at the time of this writing was ±0.15x10-28 e cm, and we hope to improve the sensitivity by a further factor of two. We will discuss recent progress and our plans to place improved limits on systematic effects.
3. Electrically Tunable Magnetism in Magnetic Topological Insulators
NASA Astrophysics Data System (ADS)
Zhang, Shou-Cheng; Wang, Jing; Lian, Biao
2015-03-01
The external controllability of the magnetic properties in topological insulators would be important both for fundamental and practical interests. Here we predict the electric-field control of ferromagnetism in a thin film of insulating magnetic topological insulators. The decrease of band inversion by the application of electric fields results in a reduction of magnetic susceptibility, and hence in the modication of magnetism. Remarkably, the electric field could even induce the magnetic quantum phase transition from ferromagnetism to paramagnetism. We further propose a topological transistor device in which the dissipationless charge transport of chiral edge states is controlled by an electric field. The simultaneous electrical control of magnetic order and chiral edge transport in such a device may lead to electronic and spintronic applications for topological insulators. This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DE-AC02-76SF00515.
4. Dynamical interaction effects on an electric dipole moving parallel to a flat solid surface
SciTech Connect
Villo-Perez, Isidro; Abril, Isabel; Garcia-Molina, Rafael; Arista, Nestor R.
2005-05-15
The interaction experienced by a fast electric dipole moving parallel and close to a flat solid surface is studied using the dielectric formalism. Analytical expressions for the force acting on the dipole, for random and for particular orientations, are obtained. Several features related to the dynamical effects on the induced forces are discussed, and numerical values are obtained for the different cases. The calculated energy loss of the electric dipole provides useful estimations which could be of interest for small-angle scattering experiments using polar molecules.
5. New search for the neutron electric dipole moment with ultracold neutrons at ILL
NASA Astrophysics Data System (ADS)
Serebrov, A. P.; Kolomenskiy, E. A.; Pirozhkov, A. N.; Krasnoschekova, I. A.; Vassiljev, A. V.; Polyushkin, A. O.; Lasakov, M. S.; Murashkin, A. N.; Solovey, V. A.; Fomin, A. K.; Shoka, I. V.; Zherebtsov, O. M.; Geltenbort, P.; Ivanov, S. N.; Zimmer, O.; Alexandrov, E. B.; Dmitriev, S. P.; Dovator, N. A.
2015-11-01
The search for an electric dipole moment (EDM) of the neutron is a crucial test for theoretical particle physics models with violation of time and spatial invariance. A new experiment recently has been carried out at the High-Flux Reactor at Institut Laue-Langevin, using the upgraded double-chamber magnetic resonance spectrometer developed at Petersburg Nuclear Physics Institute. The result is interpreted as an upper limit on the value of the neutron EDM, | dn|<5.5 × 10-26ecm (90% C.L.). This article provides a detailed description of the setup and experimental procedures, along with a discussion of possibilities for further improvement of the experimental accuracy.
6. Estimation of Systematic Errors for Deuteron Electric Dipole Moment Search at COSY
NASA Astrophysics Data System (ADS)
Chekmenev, Stanislav
2016-02-01
An experimental method which is aimed to find a permanent EDM of a charged particle was proposed by the JEDI (Jülich Electric Dipole moment Investigations) collaboration. EDMs can be observed by their influence on spin motion. The only possible way to perform a direct measurement is to use a storage ring. For this purpose, it was decided to carry out the first precursor experiment at the Cooler Synchrotron (COSY). Since the EDM of a particle violates CP invariance it is expected to be tiny, treatment of all various sources of systematic errors should be done with a great level of precision. One should clearly understand how misalignments of the magnets affects the beam and the spin motion. It is planned to use a RF Wien filter for the precusor experiment. In this paper the simulations of the systematic effects for the RF Wien filter device method will be discussed.
7. Electric and magnetic fields
NASA Technical Reports Server (NTRS)
Kaufman, H. R.; Robinson, R. S.; Etters, R. D.
1982-01-01
A number of energy momentum anomalies are described that result from the use of Abraham-Lorentz electromagnetic theory. These anomalies have in common the motion of charged bodies or current carrying conductors relative to the observer. The anomalies can be avoided by using the nonflow approach, based on internal energy of the electromagnetic field. The anomalies can also be avoided by using the flow approach, if all contributions to flow work are included. The general objective of this research is a fundamental physical understanding of electric and magnetic fields which, in turn, might promote the development of new concepts in electric space propulsion. The approach taken is to investigate quantum representations of these fields.
8. Electric dipole moments and polarizability in the quark-diquark model of the neutron
SciTech Connect
Srivastava, Y. N.; Widom, A.; Swain, J.; Panella, O.
2010-11-01
For a bound state internal wave function respecting parity symmetry, it can be rigorously argued that the mean electric dipole moment must be strictly zero. Thus, both the neutron, viewed as a bound state of three quarks, and the water molecule, viewed as a bound state of ten electrons, two protons, and an oxygen nucleus, have zero mean electric dipole moments. Yet, the water molecules are said to have a nonzero dipole moment strength d=e{Lambda} with {Lambda}{sub H{sub 2O{approx_equal}}}0.385 A. The neutron may also be said to have an electric dipole moment strength with {Lambda}{sub neutron{approx_equal}}0.612 fm. The neutron analysis can be made experimentally consistent, if one employs a quark-diquark model of neutron structure.
9. Search For The Electric Dipole Moment Of The Neutron
SciTech Connect
Grinten, Maurits van der
2006-07-11
We report on the nEDM experiment at the Institut Laue Langevin (ILL), based on a precision measurement of the Larmor precession frequency of polarised ultra-cold neutrons stored in a cell in a magnetic field. An EDM would reveal itself by a response of the Larmor precession frequency of the neutron to an electric field applied over the storage volume. The experiment has been taking data over a period of six years and has subsequently been running for one year devoted to systematic studies related to the experiment. These systematic studies have now been completed. This experiment will result in an EDM measurement with a sensitivity of the order of 10-26 e cm. The experimental techniques used in the experiment are presented as well as the systematic studies and results of the data analysis of the experiment.
10. Exploration of resistive targets within shallow marine environments using the Circular Electrical Dipole and the Differential Electrical Dipole methods: A time-domain modelling study
NASA Astrophysics Data System (ADS)
Haroon, Amir; Mogilatov, Vladimir; Goldman, Mark; Bergers, Rainer; Tezkan, Bülent
2016-02-01
Two novel transient controlled source electromagnetic methods called Circular Electrical Dipole (CED) and Differential Electrical Dipole (DED) are theoretically analysed for applications in shallow marine environments. One-dimensional and three-dimensional time-domain modelling studies are used to investigate the detectability and applicability of the methods when investigating resistive layers/targets representing hydrocarbon-saturated formations. The results are compared to the conventional time domain horizontal electrical dipole (HED) and vertical electrical dipole (VED) sources. The applied theoretical modelling studies demonstrate that CED and DED have higher signal detectability towards resistive targets compared to TD-CSEM, but demonstrate significantly poorer signal amplitudes. Future CED/DED applications will have to solve this issue prior to measuring. Furthermore, the two novel methods have very similar detectability characteristics towards 3D resistive targets embedded in marine sediments as VED while being less susceptible towards non-verticality. Due to the complex transmitter design of CED/DED the systems are prone to geometrical errors. Modelling studies show that even small transmitter inaccuracies have strong affects on the signal characteristics of CED making an actual marine application difficult at the present time. In contrast, the DED signal is less affected by geometrical errors in comparison to CED and may therefore be more adequate for marine applications.
11. Exploration of resistive targets within shallow marine environments using the circular electrical dipole and the differential electrical dipole methods: a time-domain modelling study
NASA Astrophysics Data System (ADS)
Haroon, Amir; Mogilatov, Vladimir; Goldman, Mark; Bergers, Rainer; Tezkan, Bülent
2016-05-01
Two novel transient controlled source electromagnetic methods called circular electrical dipole (CED) and differential electrical dipole (DED) are theoretically analysed for applications in shallow marine environments. 1-D and 3-D time-domain modelling studies are used to investigate the detectability and applicability of the methods when investigating resistive layers/targets representing hydrocarbon-saturated formations. The results are compared to the conventional time-domain horizontal electrical dipole (HED) and vertical electrical dipole (VED) sources. The applied theoretical modelling studies demonstrate that CED and DED have higher signal detectability towards resistive targets compared to TD-CSEM, but demonstrate significantly poorer signal amplitudes. Future CED/DED applications will have to solve this issue prior to measuring. Furthermore, the two novel methods have very similar detectability characteristics towards 3-D resistive targets embedded in marine sediments as VED while being less susceptible towards non-verticality. Due to the complex transmitter design of CED/DED the systems are prone to geometrical errors. Modelling studies show that even small transmitter inaccuracies have strong effects on the signal characteristics of CED making an actual marine application difficult at the present time. In contrast, the DED signal is less affected by geometrical errors in comparison to CED and may therefore be more adequate for marine applications.
12. MAGNETIC FIELD MEASUREMENTS OF HD2, A HIgh Nb3Sn DIPOLE MAGNET
SciTech Connect
Wang, X.; Caspi, S.; Cheng, D. W.; Felice, H.; Ferracin, P.; Hafalia, R. R.; Joseph, J. M.; Lietzke, A. F.; Lizarazo, J.; McInturff, A. D.; Sabbi, G. L.; Sasaki, K.
2009-05-04
The Superconducting Magnet Program at Lawrence Berkeley National Laboratory has designed and tested HD2, a 1 m long Nb{sub 3}Sn accelerator-type dipole based on a simple block-type coil geometry with flared ends. HD2 represents a step toward the development of cost-effective accelerator quality magnets operating in the range of 13-15 T. The design was optimized to minimize geometric harmonics and to address iron saturation and conductor magnetization effects. Field quality was measured during recent cold tests. The measured harmonics are presented and compared to the design values.
13. Solar rotating magnetic dipole?. [around axis perpendicular to rotation axis of the sun
NASA Technical Reports Server (NTRS)
Antonucci, E.
1974-01-01
A magnetic dipole rotating around an axis perpendicular to the rotation axis of the sun can account for the characteristics of the surface large-scale solar magnetic fields through the solar cycle. The polarity patterns of the interplanetary magnetic field, predictable from this model, agree with the observed interplanetary magnetic sector structure.
14. Test results of a single aperture 10 tesla dipole model magnet for the Large Hadron Collider
SciTech Connect
Yamamoto, Akira; Shintomi, Takakazu; Kimura, Nobuhiro
1996-07-01
A single aperture dipole magnet has been developed with a design magnetic field of 10 tesla by using Nb-Ti/Cu conductor to be operated at 1.8 K in pressurized super fluid helium. The magnet features double shell coil design by using high keystone Rutherford cable and compact non-magnetic steel collars to be adaptable in split/symmetric coil/collar design for twin aperture dipoles. A design central magnetic field of 10 tesla has been successfully achieved in excitation at 1.95 K in pressurized superfluid helium. Test results of the magnet with a summary of the design and fabrication will be presented.
15. Nb3Sn accelerator magnet technology scale up using cos-theta dipole coils
SciTech Connect
Nobrega, F.; Andreev, N.; Ambrosio, G.; Barzi, E.; Bossert, R.; Carcagno, R.; Chlachidze, G.; Feher, S.; Kashikhin, V.S.; Kashikhin, V.V.; Lamm, M.J.; /Fermilab
2007-06-01
Fermilab is working on the development of Nb{sub 3}Sn accelerator magnets using shell-type dipole coils and the wind-and-react method. As a part of the first phase of technology development, Fermilab built and tested six 1 m long dipole model magnets and several dipole mirror configurations. The last three dipoles and two mirrors reached their design fields of 10-11 T. The technology scale up phase has started by building 2 m and 4 m dipole coils and testing them in a mirror configuration in which one of the two coils is replaced by a half-cylinder made of low carbon steel. This approach allows for shorter fabrication times and extensive instrumentation preserving almost the same level of magnetic field and Lorentz forces in the coils as in a complete dipole model magnet. This paper presents details on the 2 m (HFDM07) and 4 m long (HFDM08) Nb{sub 3}Sn dipole mirror magnet design and fabrication technology, as well as the magnet test results which are compared with 1 m long models.
16. Comparative anatomy of dipole magnets or the magnet designer's coloring book
SciTech Connect
Meuser, R.B.
1983-04-01
A collection of dipole magnet cross sections is presented together with an indication of how they are related geometrically. The relationships indicated do not necessarily imply the actual path of evolutionary development. Brief consideration is given to magnets of higher multipole order, i.e., quadrupole magnets, etc.). The magnets under consideration have currents parallel to the axis except at the ends, and are long. The relationship between current distribution and magnetic field is essentially two-dimensional. The coils are usually surrounded by an iron yoke, but the emphasis is on conductor-dominated configurations capable of producing a rather uniform magnetic field in the aperture; the iron usually has a small effect.
17. Direct detection of light anapole and magnetic dipole DM
SciTech Connect
Nobile, Eugenio Del; Gelmini, Graciela B.; Huh, Ji-Haeng; Gondolo, Paolo E-mail: [email protected] E-mail: [email protected]
2014-06-01
We present comparisons of direct detection data for ''light WIMPs'' with an anapole moment interaction (ADM) and a magnetic dipole moment interaction (MDM), both assuming the Standard Halo Model (SHM) for the dark halo of our galaxy and in a halo-independent manner. In the SHM analysis we find that a combination of the 90% CL LUX and CDMSlite limits or the new 90% CL SuperCDMS limit by itself exclude the parameter space regions allowed by DAMA, CoGeNT and CDMS-II-Si data for both ADM and MDM. In our halo-independent analysis the new LUX bound excludes the same potential signal regions as the previous XENON100 bound. Much of the remaining signal regions is now excluded by SuperCDMS, while the CDMSlite limit is much above them. The situation is of strong tension between the positive and negative search results both for ADM and MDM. We also clarify the confusion in the literature about the ADM scattering cross section.
18. Self-force on an electric dipole in the spacetime of a cosmic string
SciTech Connect
Muniz, C.R.; Bezerra, V.B.
2014-01-15
We calculate the electrostatic self-force on an electric dipole in the spacetime generated by a static, thin, infinite and straight cosmic string. The electric dipole is held fixed in different configurations, namely, parallel, perpendicular to the cosmic string and oriented along the azimuthal direction around this topological defect, which is stretched along the z axis. We show that the self-force is equivalent to an interaction of the electric dipole with an effective dipole moment which depends on the linear mass density of the cosmic string and on the configuration. The plots of the self-forces as functions of the parameter which determines the angular deficit of the cosmic string are shown for those different configurations. -- Highlights: •Review of regularized Green’s function applied to the problem. •Self-force on an electric dipole in the string spacetime for some orientations. •Representation via graphs of the self-forces versus angular parameter of the cosmic string. •Self-force induced by the string seen as an interaction between two dipoles. •Discussion about the superposition principle in this non-trivial background.
19. Full QCD calculation of neutron electric dipole moment with the external electric field method
SciTech Connect
Shintani, E.; Aoki, S.; Kuramashi, Y.
2008-07-01
We have calculated the neutron electric dipole moment (EDM) in the presence of the CP violating {theta} term in lattice QCD with two-flavor dynamical clover quarks, using the external electric field method. Accumulating a large number of statistics by the averages over 16 different source points and over forward and backward nucleon propagators, we have obtained nonzero signals of neutron and proton EDM beyond 1 standard deviation at each quark mass in full QCD. We have investigated the quark mass dependence of nucleon EDM in full QCD, and have found that nucleon EDM in full QCD does not decrease toward the chiral limit, as opposed to the theoretical expectation. We briefly discuss possible reasons for this behavior.
20. A class of Fourier integrals based on the electric potential of an elongated dipole.
PubMed
Skianis, Georgios Aim
2014-01-01
In the present paper the closed expressions of a class of non tabulated Fourier integrals are derived. These integrals are associated with a group of functions at space domain, which represent the electric potential of a distribution of elongated dipoles which are perpendicular to a flat surface. It is shown that the Fourier integrals are produced by the Fourier transform of the Green's function of the potential of the dipole distribution, times a definite integral in which the distribution of the polarization is involved. Therefore the form of this distribution controls the expression of the Fourier integral. Introducing various dipole distributions, the respective Fourier integrals are derived. These integrals may be useful in the quantitative interpretation of electric potential anomalies produced by elongated dipole distributions, at spatial frequency domain. PMID:26034699
1. Heat leak testing of a superconducting RHIC dipole magnet at Brookhaven National Laboratory
SciTech Connect
DeLalio, J.T.; Brown, D.P.; Sondericker, J.H.
1993-09-01
Brookhaven National Laboratory is currently performing heat load tests on a superconducting dipole magnet. The magnet is a prototype of the 360, 8 cm bore, arc dipole magnets that will be used in the Relativistic Heavy Ion Collider (RMC). An accurate measurement of the heat load is needed to eliminate cumulative errors when determining the REUC cryogenic system load requirements. The test setup consists of a dipole positioned between two quadrupoles in a common vacuum tank and heat shield. Piping and instrumentation are arranged to facilitate measurement of the heat load on the primary 4.6 K magnet load and the secondary 55 K heat shield load. Initial results suggest that the primary heat load is well below design allowances. The secondary load was found to be higher than estimated, but remained close to the budgeted amount. Overall, the dipole performed to specifications.
2. Electric dipole moment of diatomic molecules by configuration interaction. IV.
NASA Technical Reports Server (NTRS)
Green, S.
1972-01-01
The theory of basis set dependence in configuration interaction calculations is discussed, taking into account a perturbation model which is valid for small changes in the self-consistent field orbitals. It is found that basis set corrections are essentially additive through first order. It is shown that an error found in a previously published dipole moment calculation by Green (1972) for the metastable first excited state of CO was indeed due to an inadequate basis set as claimed.
3. Regular and chaotic dynamics of a chain of magnetic dipoles with moments of inertia
SciTech Connect
Shutyi, A. M.
2009-05-15
The nonlinear dynamic modes of a chain of coupled spherical bodies having dipole magnetic moments that are excited by a homogeneous ac magnetic field are studied using numerical analysis. Bifurcation diagrams are constructed and used to find conditions for the presence of several types of regular, chaotic, and quasi-periodic oscillations. The effect of the coupling of dipoles on the excited dynamics of the system is revealed. The specific features of the Poincare time sections are considered for the cases of synchronous chaos with antiphase synchronization and asynchronous chaos. The spectrum of Lyapunov exponents is calculated for the dynamic modes of an individual dipole.
4. Prospects for measuring the electric dipole moment of the electron using electrically trapped polar molecules.
PubMed
Tarbutt, M R; Hudson, J J; Sauer, B E; Hinds, E A
2009-01-01
Heavy polar molecules can be used to measure the electric dipole moment of the electron, which is a sensitive probe of physics beyond the Standard Model. The value is determined by measuring the precession of the molecule's spin in a plane perpendicular to an applied electric field. The longer this precession evolves coherently, the higher the precision of the measurement. For molecules in a trap, this coherence time could be very long indeed. We evaluate the sensitivity of an experiment where neutral molecules are trapped electrically, and compare this to an equivalent measurement in a molecular beam. We consider the use of a Stark decelerator to load the trap from a supersonic source, and calculate the deceleration efficiency for YbF molecules in both strong-field seeking and weak-field seeking states. With a 1 s holding time in the trap, the statistical sensitivity could be ten times higher than it is in the beam experiment, and this could improve by a further factor of five if the trap can be loaded from a source of larger emittance. We study some effects due to field inhomogeneity in the trap and find that rotation of the electric field direction, leading to an inhomogeneous geometric phase shift, is the primary obstacle to a sensitive trap-based measurement. PMID:20151537
5. Full kinetic simulations of plasma flow interactions with meso- and microscale magnetic dipoles
NASA Astrophysics Data System (ADS)
Ashida, Y.; Usui, H.; Shinohara, I.; Nakamura, M.; Funaki, I.; Miyake, Y.; Yamakawa, H.
2014-12-01
We examined the plasma flow response to meso- and microscale magnetic dipoles by performing three-dimensional full particle-in-cell simulations. We particularly focused on the formation of a magnetosphere and its dependence on the intensity of the magnetic moment. The size of a magnetic dipole immersed in a plasma flow can be characterized by a distance L from the dipole center to the position where the pressure of the local magnetic field becomes equal to the dynamic pressure of the plasma flow under the magnetohydrodynamics (MHD) approximation. In this study, we are interested in a magnetic dipole whose L is smaller than the Larmor radius of ions riL calculated with the unperturbed dipole field at the distance L from the center. In the simulation results, we confirmed the clear formation of a magnetosphere consisting of a magnetopause and a tail region in the density profile, although the spatial scale is much smaller than the MHD scale. One of the important findings in this study is that the spatial profiles of the plasma density as well as the current flows are remarkably affected by the finite Larmor radius effect of the plasma flow, which is different from the Earth's magnetosphere. The magnetopause found in the upstream region is located at a position much closer to the dipole center than L. In the equatorial plane, we also found an asymmetric density profile with respect to the plasma flow direction, which is caused by plasma gyration in the dipole field region. The ion current layers are created in the inner region of the dipole field, and the electron current also flows in the region beyond the ion current layer because ions with a large inertia can closely approach the dipole center. Unlike the ring current structure of the Earth's magnetosphere, the current layers in the microscale dipole fields are not circularly closed around the dipole center. Since the major current is caused by the particle gyrations, the current is independently determined to be in the direction of the electron and ion gyrations, which are the same in both the upstream and downstream regions. The present analysis on the formation of a magnetosphere in the regime of a microscale magnetic dipole is significant for understanding the solar wind response to the crustal magnetic anomalies on the Moon surface, such as were recently observed by spacecraft.
6. Full kinetic simulations of plasma flow interactions with meso- and microscale magnetic dipoles
SciTech Connect
Ashida, Y.; Yamakawa, H.; Usui, H.; Miyake, Y.; Shinohara, I.; Funaki, I.; Nakamura, M.
2014-12-15
We examined the plasma flow response to meso- and microscale magnetic dipoles by performing three-dimensional full particle-in-cell simulations. We particularly focused on the formation of a magnetosphere and its dependence on the intensity of the magnetic moment. The size of a magnetic dipole immersed in a plasma flow can be characterized by a distance L from the dipole center to the position where the pressure of the local magnetic field becomes equal to the dynamic pressure of the plasma flow under the magnetohydrodynamics (MHD) approximation. In this study, we are interested in a magnetic dipole whose L is smaller than the Larmor radius of ions r{sub iL} calculated with the unperturbed dipole field at the distance L from the center. In the simulation results, we confirmed the clear formation of a magnetosphere consisting of a magnetopause and a tail region in the density profile, although the spatial scale is much smaller than the MHD scale. One of the important findings in this study is that the spatial profiles of the plasma density as well as the current flows are remarkably affected by the finite Larmor radius effect of the plasma flow, which is different from the Earth's magnetosphere. The magnetopause found in the upstream region is located at a position much closer to the dipole center than L. In the equatorial plane, we also found an asymmetric density profile with respect to the plasma flow direction, which is caused by plasma gyration in the dipole field region. The ion current layers are created in the inner region of the dipole field, and the electron current also flows in the region beyond the ion current layer because ions with a large inertia can closely approach the dipole center. Unlike the ring current structure of the Earth's magnetosphere, the current layers in the microscale dipole fields are not circularly closed around the dipole center. Since the major current is caused by the particle gyrations, the current is independently determined to be in the direction of the electron and ion gyrations, which are the same in both the upstream and downstream regions. The present analysis on the formation of a magnetosphere in the regime of a microscale magnetic dipole is significant for understanding the solar wind response to the crustal magnetic anomalies on the Moon surface, such as were recently observed by spacecraft.
7. Production of trilobite Rydberg molecule dimers with kilo-Debye permanent electric dipole moments
NASA Astrophysics Data System (ADS)
Booth, D.; Rittenhouse, S. T.; Yang, J.; Sadeghpour, H. R.; Shaffer, J. P.
2015-04-01
Permanent electric dipole moments are important for understanding symmetry breaking in molecular physics, control of chemical reactions, and realization of strongly correlated many-body quantum systems. However, large molecular permanent electric dipole moments are challenging to realize experimentally. We report the observation of ultralong-range Rydberg molecules with bond lengths of ~100 nanometers and kilo-Debye permanent electric dipole moments that form when an ultracold ground-state cesium (Cs) atom becomes bound within the electronic cloud of an extended Cs electronic orbit. The electronic character of this hybrid class of “trilobite” molecules is dominated by degenerate Rydberg manifolds, making them difficult to produce by conventional photoassociation. We used detailed coupled-channel calculations to reproduce their properties quantitatively. Our findings may lead to progress in ultracold chemistry and strongly correlated many-body physics.
8. Magnetohydrodynamic Simulations of Hypersonic Flow over a Cylinder Using Axial- and Transverse-Oriented Magnetic Dipoles
PubMed Central
Guarendi, Andrew N.; Chandy, Abhilash J.
2013-01-01
Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (≪1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source terms such as Lorentz force and Joule dissipation. The results demonstrate the ability of the magnetic field to affect the flowfield around the cylinder, which results in an increase in shock stand-off distance and reduction in overall temperature. Also, it is observed that there is a noticeable decrease in drag with the addition of the magnetic field. PMID:24307870
9. Magnetohydrodynamic simulations of hypersonic flow over a cylinder using axial- and transverse-oriented magnetic dipoles.
PubMed
Guarendi, Andrew N; Chandy, Abhilash J
2013-01-01
Numerical simulations of magnetohydrodynamic (MHD) hypersonic flow over a cylinder are presented for axial- and transverse-oriented dipoles with different strengths. ANSYS CFX is used to carry out calculations for steady, laminar flows at a Mach number of 6.1, with a model for electrical conductivity as a function of temperature and pressure. The low magnetic Reynolds number (<1) calculated based on the velocity and length scales in this problem justifies the quasistatic approximation, which assumes negligible effect of velocity on magnetic fields. Therefore, the governing equations employed in the simulations are the compressible Navier-Stokes and the energy equations with MHD-related source terms such as Lorentz force and Joule dissipation. The results demonstrate the ability of the magnetic field to affect the flowfield around the cylinder, which results in an increase in shock stand-off distance and reduction in overall temperature. Also, it is observed that there is a noticeable decrease in drag with the addition of the magnetic field. PMID:24307870
10. Dynamics of the magnetic moments for chain of dipoles in domain wall
NASA Astrophysics Data System (ADS)
Shutyıˇ, Anatoliy M.; Sementsov, Dmitriy I.
2016-03-01
We report on the dynamics of the magnetic moment numerically simulated for a chain of the magnetic nanodots coupled through the dipole-dipole interaction and in the presence of the magnetic anisotropy of various types. It is shown that a static field applied to the system causes specific fluctuations of the transverse components of the magnetic moment leading to a sequence of the oscillation trains observed in the domain wall. Various oscillation modes governed by the external alternating field are revealed. The influence of the unidirectional and uniaxial anisotropy ("easy-plane" and "easy axis" anisotropy) on the system behavior is described.
11. Measurements of passive correction of magnetization higher multipoles in one meter long dipoles
SciTech Connect
Green, M.A.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Gilbert, W.S.; Green, M.I.; Scanlan, R.M.; Taylor, C.E.
1990-09-01
The use of passive superconductor to correct the magnetization sextupole and decapole in SSC dipoles appears to be promising. This paper presents the results of a series of experiments of passive superconductor correctors in one meter long dipole magnets. Reduction of the magnetization sextupole by a factor of five to ten has been achieved using the passive superconductor correctors. The magnetization decapole was also reduced. The passive superconductor correctors reduced the sextupole temperature sensitivity by an order of magnitude. Flux creep decay was partially compensated for by the correctors. 13 refs., 7 figs.
12. Implications of stochastic magnetization dynamics on reliability of dipole coupled nanomagnetic logic
NASA Astrophysics Data System (ADS)
Salehi Fashami, Mohammad; Atulasimha, Jayasimha; Bandyopadhyay, Supriyo
2013-03-01
Straintronic nanomagnetic logic (SML), where Boolean computation is elicited from dipole coupled multiferroic nanomagnets switched with electrically generated strain, has emerged as an extremely energy-efficient computing paradigm. We have studied the reliability of such logic circuits by computing the gate error rates in the presence of thermal noise by simulating switching trajectories with the stochastic Landau-Lifshitz-Gilbert (LLG) equation. In addition, we examine the lower bound of energy dissipation as a function of switching error and explain how the out-of-plane excursion of the magnetization vector leads to excess energy dissipation over this bound for a given switching error. This analysis is performed to understand the connection between reliability and energy dissipation for a single switch and then extended to larger nanomagnetic logic circuits to assess the viability of dipole coupled SML. This work is supported by the US National Science Foundation under the SHF-Small grant CCF-1216614, NEB 2020 grant ECCS-1124714 and by the Semiconductor Research Corporation (SRC) under NRI Task 2203.001.
13. Polarity reversals and tilt of the Earth's magnetic dipole
NASA Technical Reports Server (NTRS)
Dolginov, A. Z.
1993-01-01
There is evidence that the terrestrial magnetic field is connected with the Earth's mantle: (1) there are magnetic anomalies that do not take part in the westward drift of the main field, but are fixed with respect to the mantle; (2) the geomagnetic pole position flips in a particular way by preferred meridional paths during a reversal; and (3) magnetic polarity reversals are correlated with the activations of geological processes. These facts may be explained if we take into account that a significant horizontal temperature gradient can exist in the top levels of the liquid core because of the different thermoconductivity of the different areas of the core-mantle boundary. These temperature inhomogeneities can penetrate the core because fluxes along the core boundary (the thermal wind) can be strongly suppressed by a small redistribution of the chemical composition in the top of the core. The nonparallel gradients of the temperature, density, and composition on the top of the core create a curled electric field that produces a current and a magnetic field. This seed-field can be amplified by motions in the core. The resulting field does not forget the seed-field distribution and in this way the field on the Earth surface (that can be created only in regions with high conductivity, i.e. in the core) is connected with the core-mantle boundary. Contrary to the usual approach to the dynamo problem, we will take into account that the seed field of thermoelectric origin is acting not only at some initial moment of time but permanently.
14. Electric dipole moments and chemical bonding of diatomic alkali-alkaline earth molecules.
PubMed
Pototschnig, Johann V; Hauser, Andreas W; Ernst, Wolfgang E
2016-02-17
We investigate the properties of alkali-alkaline earth diatomic molecules in the lowest Σ(+) states of the doublet and quartet multiplicity by ab initio calculations. In all sixteen cases studied, the permanent electric dipole moment points in opposite directions for the two spin states. This peculiarity can be explained by molecular orbital theory. We further discuss dissociation energies and bond distances. We analyze trends and provide an empirically motivated model for the prediction of the permanent electric dipole moment for combinations of alkali and alkaline earth atoms not studied in this work. PMID:26837666
15. Electric dipole response of {sup 208}Pb and constraints on the symmetry energy
SciTech Connect
Tamii, A.
2014-05-02
The electric dipole (E1) response of {sup 208}Pb has been precisely determined by measuring polarized proton inelastic scattering at very forward angles including zero degrees. The electric dipole polarizability, that is defined as the inverse energy-weighted sum rule of the E1 reduced transition strength, has been extracted as α{sub D} = 20.1 ±0.6 fm{sup 3}. A constraint band has been extracted in the plane of the symmetry energy (J) and its slope parameter (L) at the saturation density.
16. Electron in the Field of a Molecule with an Electric Dipole Moment
SciTech Connect
Alhaidari, A. D.; Bahlouli, H.
2008-03-21
In solving the eigenvalue wave equation, we relax the usual diagonal constraint on its matrix representation by allowing it to be tridiagonal. This results in a larger representation space that incorporates an analytic solution for the noncentral electric dipole pole potential cos{theta}/r{sup 2}, which was believed not to belong to the class of exactly solvable potentials. Consequently, we obtain closed form solution of the time-independent Schroedinger equation for an electron in the field of a molecule treated as a point electric dipole.
17. Designs and measurements of gradient dipole magnets for the upgrade of Pohang Light Source
NASA Astrophysics Data System (ADS)
Chen, Y.; Kim, D. E.; Kang, W.; Chen, F. S.; Yang, M.; Zhang, Z.; Yin, B. G.; Zhou, J. X.
2012-08-01
The compact size of the upgrade of Pohang Light Source (PLS-II) ring implies the use of gradient dipole magnets, with high field quality requirements. The PLS-II ring contains 24 such dipoles. Detailed 2D and 3D physical designs are reported; they include conformal mapping, equivalent 2D compact factor, residues fitting technique and end chamfer in a concise straight line style. According to the field measurement results, a beam based alignment technique for the rms variation reduction was employed. With that, the uniformities for these dipoles can be reduced to less than 2.0E-04, and the rms variation from dipole to dipole can reach 5.82E-04.
18. Electric & Magnetic Fields
MedlinePlus
... radiation , that are associated with the use of electrical power and various forms of natural and man-made ... exposures stemming from conventional power sources, such as power lines, electrical substations, or home appliances. While some of these ...
19. The dynamics of high energy density plasma jets magnetized by large dipole magnetic fields
NASA Astrophysics Data System (ADS)
Gourdain, Pierre; Byvank, Tom; Hammer, Dave; Kusse, Bruce; Seyler, Charlie; Bland, Simon; Lebedev, Sergey; Swadling, George
2014-10-01
Astrophysical plasma jets expelled by proto-stars or galactic nuclei are often magnetized by the magnetic field that the star or galaxy generates. This field resembles the one of a dipole and, while strong near the celestial body, the field decays rapidly away from the source. Experimental observations of supersonic high energy density plasma jets generated in the laboratory by radial foils have shown that the field impacts strongly the dynamics of the jet. Such jets share some similarities with astrophysical jets in the magneto-hydrodynamics sense, e.g. large Reynolds, magnetic Reynolds and Peclet numbers. This work shows how a dipole field generated at the base of the supersonic jet affects the plasma dynamics. In regions where the plasma beta is low (near the base of the jet), the jet is conical. At higher altitudes, where the beta is high, the jet is strongly collimated. Numerical computations highlight the mechanisms responsible for such transitions. Research supported by NSF Grant # PHY-1102471, the DOE Grant # DE-SC0002151 and the NNSA/DOE Cooperative Agreement DE-NA0001836 and DE-NA0001847.
20. A robust limit for the electric dipole moment of the electron
NASA Astrophysics Data System (ADS)
Jung, Martin
2013-05-01
Electric dipole moments constitute a competitive method to search for new physics, being particularly sensitive to new CP -violating phases. Given the experimental and theoretical progress in this field and more generally in particle physics, the necessity for more reliable bounds than the ones usually employed emerges. We therefore propose an improved extraction of the electric dipole moment of the electron and the relevant coefficient of the electron-nucleon coupling, taking into account theoretical uncertainties and possible cancellations, to be used in model-dependent analyses. Specifically, we obtain at 95% C.L. | d e | ≤ 0.14 × 10-26 e cm with present data, which is very similar to the bound typically quoted from the YbF molecule, but obtained in a more conservative manner. We examine furthermore in detail the prospects for improvements and derive upper limits for the dipole moments of several paramagnetic systems presently under investigation, i.e. cesium, rubidium and francium.
1. First Measurement of the Atomic Electric Dipole Moment of (225)Ra.
PubMed
Parker, R H; Dietrich, M R; Kalita, M R; Lemke, N D; Bailey, K G; Bishof, M; Greene, J P; Holt, R J; Korsch, W; Lu, Z-T; Mueller, P; O'Connor, T P; Singh, J T
2015-06-12
The radioactive radium-225 ((225)Ra) atom is a favorable case to search for a permanent electric dipole moment. Because of its strong nuclear octupole deformation and large atomic mass, (225)Ra is particularly sensitive to interactions in the nuclear medium that violate both time-reversal symmetry and parity. We have developed a cold-atom technique to study the spin precession of (225)Ra atoms held in an optical dipole trap, and demonstrated the principle of this method by completing the first measurement of its atomic electric dipole moment, reaching an upper limit of |d((225)Ra)|<5.0×10(-22) e cm (95% confidence). PMID:26196797
2. Model SSC (Superconducting Super Collider) dipole magnet cryostat assembly at Fermilab
SciTech Connect
Niemann, R.C.
1989-03-01
The Superconducting Super Collider (SSC) magnet development program includes the design, fabrication and testing of full length model dipole magnets. A result of the program has been the development of a magnet cryostat design. The cryostat subsystems consist of cold mass connection-slide, suspension, thermal shields, insulation, vacuum vessel and interconnections. Design details are presented along with model magnet production experience. 6 refs., 13 figs.
3. Modeling the interaction of solar wind with a dipole magnetic field with Shenguang II intense lasers
NASA Astrophysics Data System (ADS)
Zhang, K.; Zhong, J. Y.; Wang, J. Q.; Pei, X. X.; Wei, H. G.; Yuan, D. W.; Yang, Z. W.; Wang, C.; Li, F.; Han, B.; Yin, C. L.; Liao, G. Q.; Fang, Y.; Yang, S.; Yuan, X. H.; Sakawa, Y.; Morita, T.; Cao, Z. R.; Jiang, S. E.; Ding, Y. K.; Kuramitsu, Y.; Liang, G. Y.; Wang, F. L.; Li, Y. T.; Zhu, J. Q.; Zhang, J.; Zhao, G.
2015-12-01
The interaction of solar wind with a dipole magnetic field is modeled in a laboratory setting with a small cylindrical permanent magnet and magnetized plasma driven by intense lasers. The result shows a potential application in the understanding of Earth's magnetosphere near the pole region. Some significant features are observed in our experiments, such as magnetic reconnection and repulsion, which agree well with magnetohydrodynamics (MHD) simulation results.
4. Comparative study of the exciton states in CdSe/ZnS core-shell quantum dots under applied electric fields with and without permanent electric dipole moment
NASA Astrophysics Data System (ADS)
Cristea, M.
2016-04-01
Due to its non-centrosymmetric wurtzite crystal structure, the CdSe dot presents a permanent electric dipole moment. In this paper we study the effect of an electric applied field on the emission wavelength of a CdSe/ZnS core-shell quantum dot with a permanent electric dipole. The electron and hole single-particle energy and wave function in the presence of an electric dipole are obtained in the effective-mass and parabolic-band approximation for various electric field strengths. The Schrödinger equation was solved by use of the finite element method. The exciton binding energy is calculated in the first-order perturbation theory and the optical emission wavelengths are found and compared to the experimental values. We find that the photoluminescence emission can be tuned by varying the electric dipole size, the electric field strength and by an appropriate orientation between the permanent dipole moment and applied electric field.
5. Design and end chamfer simulation of PEFP beam line curved dipole magnets
NASA Astrophysics Data System (ADS)
Zhu, Ying-Shun; Yang, Mei; Zhang, Zhuo; Chen, Wan; Yin, Bao-Gui; Shi, Cai-Tu; Kang, Wen
2011-07-01
The design, fabrication and field measurement of 11 DC curved dipole magnets for the PEFP Beam Line have been completed. In this paper, a design method for a complex end chamfer using OPERA-3D is proposed. The conventional method for estimating chamfer shape is extended and applied to a curved dipole magnet by a coordinate transformation. Using the interface with CAD software, the complex end chamfer is modeled and fully determined by 3D simulation to meet the field uniformity requirement. The magnetic field measurement results are in good agreement with the simulation. The design considerations, field simulation results, end chamfer development process and measurement results are presented in detail.
6. Quench performance of 50-mm aperture, 15-m-long SSC dipole magnets built at Fermilab
SciTech Connect
Kuzminski, J.; Bush, T.; Coombes, R.
1992-07-01
The quench performance, ramp rate dependence, and mechanical behavior of ten full-length, 50-mm-aperture, SSC dipole magnets built at Fermilab are discussed. Cold testing of these magnets shows that the quench plateau established at 4.35 K exceeds the design value by more than 10%, virtually without training.
7. Test results of BNL built 40-mm aperture, 17-m-long SSC collider dipole magnets
SciTech Connect
Kuzminski, J.; Bush, T.; Coombes, R.; Devred, A.; DiMarco, J.; Goodzeit, C.; Puglisi, M.; Radusewicz, P.; Sanger, P.; Schermer, R. )
1992-01-01
Eleven 17 m long, 40 mm aperture SSC R and D superconducting collider dipole magnets, built at BNL, have been extensively tested at BNL and Fermilab during 1990-91. In this paper quench performance of these magnets and details of their mechanical behavior are presented.
8. Test results of BNL built 40-mm aperture, 17-m-long SSC collider dipole magnets
SciTech Connect
Kuzminski, J.; Bush, T.; Coombes, R.; Devred, A.; DiMarco, J.; Goodzeit, C.; Puglisi, M.; Radusewicz, P.; Sanger, P.; Schermer, R.; Tompkins, J.C.; Wolf, Z.; Yu, Y.; Zheng, H. ); Ogitsu, T. National Lab. for High Energy Physics, Tsukuba, Ibaraki ); Anerella, M.; Cottingham, J.
1991-06-01
Eleven 17 m long, 40 mm aperture SSC R D superconducting collider dipole magnets, built at BNL, have been extensively tested at BNL and Fermilab during 1990--91. Quench performance of these magnets and details of their mechanical behavior are presented. 7 refs., 5 figs.
9. Electric dipole moments for a CP-violating neutral Higgs sector
SciTech Connect
Gunion, J.F.
1992-12-31
The authors briefly survey the consequences for the electric dipole moments of the electron and neutron (d{sub e} and d{sub n}, respectively) of a neutral Higgs sector that is CP-violating. They find that current experimental limits are on the verge of placing significant constraints on such CP violation.
10. The 2H electric dipole moment in a separable potential approach
SciTech Connect
Gibson, Benjamin; Afnan, I. R.
2009-01-01
Measurement of the electric dipole moment of H or HE may well come prior to the coveted measurement of the neutron EDM. Exact model calculations for the deuteron are feasible, and we explore here the model dependence of such deuteron EDM calculations.
11. Interpretation of dipole-dipole electrical resistivity survey, Colado geothermal area, Pershing County, Nevada
NASA Astrophysics Data System (ADS)
Mackelprang, C. E.
1980-09-01
An electrical resistivity survey in the Colado geothermal area, Pershing County, Nevada has defined areas of low resistivity on each of five lines surveyed. Some of these areas appear to be fault controlled. Thermal fluids encountered in several drill holes support the assumption that the hot fluids may be associated with areas of low resistivity. The evidence of faulting as interpreted from modeling of the observed resistivity data is therefore particularly significant since these structures may be the conduits for the thermal fluids. Sub-alluvial fault zones are interpreted to occur between stations 0-5 NW on Line D and on Line A between stations 4 NW and 4 SE. Fault zones are also interpreted on Line C near stations 1 NW, 1 SE, and 3 SE, and on Line E between stations 2-4 NW and near 1 SE. No faulting is evident under the alluvial cover on the southwest end of Line B. A deep conductive zone is noted within the mountain range on two resistivity lines. There is no definite indication that thermal fluids are associated with this resistivity feature.
12. Magnetic levitation for effective loading of cold cesium atoms in a crossed dipole trap
NASA Astrophysics Data System (ADS)
Li, Yuqing; Feng, Guosheng; Xu, Rundong; Wang, Xiaofeng; Wu, Jizhou; Chen, Gang; Dai, Xingcan; Ma, Jie; Xiao, Liantuan; Jia, Suotang
2015-05-01
13. Search for a permanent electric dipole moment using liquid 129Xe
SciTech Connect
PROFESSOR MICHAEL ROMALIS
2008-11-24
Search for an electric dipole moment is one of the best motivated low-energy approaches for investigating physics beyond the Standard Model. Our experimental effort is focused on improving the limit on EDM in liquid 129Xe to put constraints on nuclear CP-violating interactions. High nuclear spin density and high electrical breakdown strength make 129Xe a promising medium for EDM searches. At the time the project started, the transverse nuclear spin relaxation time T2 of 129Xe was unknown. We made measurements of T2 using NMR spin-echo techniques and found that it is exceeds 1300 sec, the longest relaxation time ever measured in a liquid [1]. We also began to investigate non-linear dipolar interaction effects in a high-density spin-polarized liquid Xe. In the second iteration of the experiment we setup a high-Tc SQUID system in magnetic shields and performed detailed studies of Xe spin precession. We developed a model for non-linear dipolar interactions and found that for one set of conditions non-linear interactions can delay spin dephasing due to magnetic field gradients, while for another set of conditions they can lead to exponential amplification of the spin precession signals [2]. Our experimental data were in good quantitative agreement with predictions of the model. We also developed a series of numerical simulations to understand various imperfections in the system and made detailed experimental measurements to confirm these numerical predictions [3]. We demonstrated that non-linear interactions can amplify small precession signals and achieved an amplification factor of 10 [4]. This general phenomenon can be used in other precision measurements with non-linear interactions. We also explored practical applications of the liquid Xe system that we developed. We demonstrated that by mixing Xe with organic liquids, such as cyclopentane, one can enhance the proton spin polarization by a factor of 106 [5]. We have used this technique to perform the first measurement of the scalar J-coupling between nuclear spins in van-der-Waals molecules, something that has never been observed before. More recently, we constructed a liquid-He apparatus to acquire Xe spin precession data using a low-Tc SQUID and achieved a signal-to-noise ratio of 106. We are currently investigating factors affecting the stability of Xe spin precession signals in this system using a superconducting magnetic shield and a persistent current magnetic field coil.
14. Regular and Chaotic Motion in General Relativity. Case of Magnetized Black Hole and a Massive Magnetic Dipole
NASA Astrophysics Data System (ADS)
Karas, Vladimir; Kovar, J.; Kopacek, O.; Kojima, Y.; Slany, P.; Stuchlik, Z.
2012-05-01
Near a rotating black hole, circular motion of particles, dust grains and complex fluids have been investigated as a model for accretion of gaseous and dusty environment in the toroidal geometry. Here we further discuss, within the framework of general relativity, figures of equilibrium of matter under the influence of combined gravitational and large-scale magnetic fields, assuming that the accreted material acquires a small (but non-vanishing) electric charge due to the interplay of plasma processes and photoionization. We employ different solutions for the central body (magnetized Kerr metric, or a massive magnetic dipole) and we identify the corresponding regions of stability. The action of gravitational and electromagnetic forces jointly determine the regions of stable motion, in particular, whether the halo lobes develop where particles can be captured in permanent circulation around the central body. Therefore, our set-up is relevant in the context of accreting compact objects where the halo motion can describe the overall global motion through corona of an accretion disc or a geometrically thick torus. We also investigate situations when the motion exhibits the onset of chaos. In order to characterize the measure of chaoticness we employ techniques of Poincare surfaces of section and Recurrence plots. Acknowledgments: Czech-US collaboration project (ref. ME09036) and the Czech Science Foundation program (ref. P209/10/P190) are gratefully acknowledged for their continued support.
15. Theoretical study of the potential energy surface and electric dipole moment of aniline
NASA Astrophysics Data System (ADS)
Farasat, Mahshid; Shojaei, S. H. Reza; Golzan, M. Maqsood; Farhadi, Khalil
2016-03-01
The potential energy surface (PES) of aniline was comprehensively investigated at different levels in this paper. The stable conformer of aniline has CS point group while the transition states possess CS and C2V symmetries. The computed transition states of aniline are highly dependent on the level of the computations including Hartree-Fock, Density functional and Moller-Plesset perturbation theories. The electric dipole moment of the molecule varies by the rotation of the amino group with respect to the phenyl plane, while in the range of 60-120 degrees, the changes of the dipole moment is not noticeable.
16. Theoretical study of the electric dipole moment function of the ClO molecule
NASA Technical Reports Server (NTRS)
Pettersson, L. G. M.; Langhoff, S. R.; Chong, D. P.
1986-01-01
The potential energy function and electric dipole moment function (EDMF) are computed for ClO X 2Pi using several different techniques to include electron correlation. The EDMF is used to compute Einstein coefficients, vibrational lifetimes, and dipole moments in higher vibrational levels. The band strength of the 1-0 fundamental transition is computed to be 12 + or - 2 per sq cm atm determined from infrared heterodyne spectroscopy. The theoretical methods used include SCF, CASSCF, multireference singles plus doubles configuration interaction (MRCI) and contracted CI, coupled pair functional (CPF), and a modified version of the CPF method. The results obtained using the different methods are critically compared.
17. Magnetic dipole moment of a spherical shell with TRM acquired in a field of internal origin. [Thermoremanent Magnetization implications for lunar magnetic field
NASA Technical Reports Server (NTRS)
Srnka, L. J.
1976-01-01
The acquisition of thermoremanent magnetization (TRM) by a cooling spherical shell is studied for internal magnetizing dipole fields, using Runcorn's (1975) theorems on magnetostatics. If the shell cools progressively inward, inner regions acquire TRM in a net field composed of the dipole source term plus a uniform field due to the outer magnetized layers. In this case, the global dipole moment and external remanent field are nonzero when the whole shell has cooled below the Curie point and the source dipole has disappeared. The remanent field outside the shell is found to depend on the thickness, radii, and cooling rate of the shell, as well as the coefficient of TRM and the intensity of the magnetizing field. Some implications for the moon's remanent dipole moment are discussed.
18. Magnetic anomaly inversion using magnetic dipole reconstruction based on the pipeline section segmentation method
NASA Astrophysics Data System (ADS)
Pan, Qi; Liu, De-Jun; Guo, Zhi-Yong; Fang, Hua-Feng; Feng, Mu-Qun
2016-06-01
In the model of a horizontal straight pipeline of finite length, the segmentation of the pipeline elements is a significant factor in the accuracy and rapidity of the forward modeling and inversion processes, but the existing pipeline segmentation method is very time-consuming. This paper proposes a section segmentation method to study the characteristics of pipeline magnetic anomalies—and the effect of model parameters on these magnetic anomalies—as a way to enhance computational performance and accelerate the convergence process of the inversion. Forward models using the piece segmentation method and section segmentation method based on magnetic dipole reconstruction (MDR) are established for comparison. The results show that the magnetic anomalies calculated by these two segmentation methods are almost the same regardless of different measuring heights and variations of the inclination and declination of the pipeline. In the optimized inversion procedure the results of the simulation data calculated by these two methods agree with the synthetic data from the original model, and the inversion accuracies of the burial depths of the two methods are approximately equal. The proposed method is more computationally efficient than the piece segmentation method—in other words, the section segmentation method can meet the requirements for precision in the detection of pipelines by magnetic anomalies and reduce the computation time of the whole process.
19. Polarization of Magnetic Dipole Emission and Spinning Dust Emission from Magnetic Nanoparticles
NASA Astrophysics Data System (ADS)
Hoang, Thiem; Lazarian, Alex
2016-04-01
Magnetic dipole emission (MDE) from interstellar magnetic nanoparticles is potentially an important Galactic foreground in the microwave frequencies, and its polarization level may pose great challenges for achieving reliable measurements of cosmic microwave background B-mode signal. To obtain realistic predictions for the polarization of MDE, we first compute the degree of alignment of big silicate grains incorporated with magnetic inclusions. We find that thermally rotating big grains with magnetic inclusions are weakly aligned and can achieve alignment saturation when the magnetic alignment rate becomes much faster than the rotational damping rate. We then compute the degree of alignment for free-flying magnetic nanoparticles, taking into account various interaction processes of grains with the ambient gas and radiation field, including neutral collisions, ion collisions, and infrared emission. We find that the rotational damping by infrared emission can significantly decrease the degree of alignment of small particles from the saturation level, whereas the excitation by ion collisions can enhance the alignment of ultrasmall particles. Using the computed degrees of alignment, we predict the polarization level of MDE from free-flying magnetic nanoparticles to be rather low. Such a polarization level is within the upper limits measured for anomalous microwave emission (AME), which indicates that MDE from free-flying iron particles may not be ruled out as a source of AME. We also quantify rotational emission from free-flying iron nanoparticles with permanent magnetic moments and find that its emissivity is about one order of magnitude lower than that from spinning polycyclic aromatic hydrocarbons.
20. Hyperfine structure of OH molecules in electric and magnetic fields
NASA Astrophysics Data System (ADS)
Maeda, Kenji; Wall, Michael L.; Carr, Lincoln D.
2014-03-01
Ultracold polar molecules offer a unique opportunity in table-top experiments to study quantum phenomena originating from strong dipole-dipole interactions and incorporating internal degrees of freedom controllable by external electric and magnetic fields. Recently, a gas of OH molecules was evaporatively cooled at JILA to milliKelvin temperatures. However, in the presence of electric and magnetic fields, the energy spectra of OH were calculated only to energy scales of mK, far from the sub-microKelvin temperatures at which OH molecules will become quantum degenerate. We investigate single-particle energy spectra of the OH radical in the lowest rovibrational and electric ground states under combined electric and magnetic fields. In addition to the fine-structure interactions, the hyperfine interactions and centrifugal distortion effects are taken into account, yielding the zero-field spectrum of the lowest 2Π3 / 2 manifold to an accuracy of less than 2kHz ~100nK. We also examine level crossings and repulsions in hyperfine structures induced by applied electric and magnetic fields. We will mention many-body applications of ultracold OH molecules to simulate quantum dipolar systems. Funded by AFOSR and NSF.
1. Radiation effects in a muon collider ring and dipole magnet protection
SciTech Connect
Mokhov, N.V.; Kashikhin, V.V.; Novitski, I.; Zlobin, A.V.; /Fermilab
2011-03-01
The requirements and operating conditions for a Muon Collider Storage Ring (MCSR) pose significant challenges to superconducting magnets. The dipole magnets should provide a high magnetic field to reduce the ring circumference and thus maximize the number of muon collisions during their lifetime. One third of the beam energy is continuously deposited along the lattice by the decay electrons at the rate of 0.5 kW/m for a 1.5-TeV c.o.m. and a luminosity of 10{sup 34} cm{sup -2}s{sup -1}. Unlike dipoles in proton machines, the MCSR dipoles should allow this dynamic heat load to escape the magnet helium volume in the horizontal plane, predominantly towards the ring center. This paper presents the analysis and comparison of radiation effects in MCSR based on two dipole magnets designs. Tungsten masks in the interconnect regions are used in both cases to mitigate the unprecedented dynamic heat deposition and radiation in the magnet coils.
2. Calculated electric dipole moment of NiH X2Delta
NASA Technical Reports Server (NTRS)
Walch, S.; Bauschlicher, C. W., Jr.; Langhoff, S. R.
1985-01-01
A calculated dipole moment of 2.39 D at R sub e = 2.79 a sub 0 is reported, obtained from complete active space SCF/configuration interaction calculations plus one natural orbital iteration. The calculation is in good agreement with the experimental value of 2.4 + or - 0.1 D measured for the lowest vibrational level. In agreement with Gray et al. (1985), it is found that the dipole moment is strongly correlated with the 3d electron population; the good agreement with experiment thus provides verification of the mixed state model of NiH. It is concluded that the electric dipole moment of NiH is a sensitive test of the quality of the NiH wave function.
3. Theoretical Study of the Electric Dipole Moment Function of the CIO Molecule
NASA Technical Reports Server (NTRS)
Pettersson, Lars G. M.; Langhoff, Stephen R.; Chong, Delano P.
1986-01-01
The potential energy function and electric dipole moment function (EDMF) are computed for CIO Chi(sup 2)Pi using several different techniques to include electron correlation. The EDMF is used to compute Einstein coefficients, vibrational lifetimes, and dipole moments in higher vibrational levels. Remaining questions concerning the position of the maximum of the EDMF may be resolved through experimental measurement of dipole moments of higher vibrational levels. The band strength of the 1-0 fundamental transition is computed to be 12 +/- 2 /sq cm atm in good agreement with three experimental values, but larger than a recent value of 5 /sq cm atm determined from infrared heterodyne spectroscopy. The theoretical methods used include SCF, CASSCF, multireference singles plus doubles configuration interaction (MRCI) and contracted CI, coupled pair functional (CPF), and a modified version of the CPF method. The results obtained using the different methods are critically compared.
4. Self-assembling of tubular skeletons from electric current filaments composed of magnetized thin rods
NASA Astrophysics Data System (ADS)
Kukushkin, A. B.; Cherepanov, K. V.
2007-04-01
Formation of a skeleton composed of a fractal condensed matter was suggested [A.B. Kukushkin, V.A. Rantsev-Kartinov, in: Proceedings of the 17th IAEA Fusion Energy Conference, vol. 3, Yokohama, Japan, 1998, pp. 1131 1134, http://www.iaea.org/programmes/ripc/physics/pdf/ifp_17.pdf ] to explain unexpected longevity of filamentary structures observed in laboratory electric discharges. A simple 3D model [A.B. Kukushkin, K.V. Cherepanov, physics/0512234] of many-body system of magnetized, electrically conducting thin rods (1D magnetic dipoles) managed to describe the integrity of a hypothetical, “manually-assembled” tubular skeleton under the action of external forces. Here we demonstrate the possibility of electrodynamic self-assembling of coaxial tubular skeleton in a system of ˜500 magnetic dipoles, which are initially arranged as 25 50 linear electric current filaments with a fraction of the dipoles with uncompensated magnetic flux.
5. Experimental verification of isotropic radiation from a coherent dipole source via electric-field-driven LC resonator metamaterials.
PubMed
Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, André
2013-09-27
It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator's gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present. PMID:24116780
6. Experimental Verification of Isotropic Radiation from a Coherent Dipole Source via Electric-Field-Driven LC Resonator Metamaterials
NASA Astrophysics Data System (ADS)
Tichit, Paul-Henri; Burokur, Shah Nawaz; Qiu, Cheng-Wei; de Lustrac, André
2013-09-01
It has long been conjectured that isotropic radiation by a simple coherent source is impossible due to changes in polarization. Though hypothetical, the isotropic source is usually taken as the reference for determining a radiator’s gain and directivity. Here, we demonstrate both theoretically and experimentally that an isotropic radiator can be made of a simple and finite source surrounded by electric-field-driven LC resonator metamaterials designed by space manipulation. As a proof-of-concept demonstration, we show the first isotropic source with omnidirectional radiation from a dipole source (applicable to all distributed sources), which can open up several possibilities in axion electrodynamics, optical illusion, novel transformation-optic devices, wireless communication, and antenna engineering. Owing to the electric- field-driven LC resonator realization scheme, this principle can be readily applied to higher frequency regimes where magnetism is usually not present.
7. Boosting the directivity of optical antennas with magnetic and electric dipolar resonant particles.
PubMed
Rolly, Brice; Stout, Brian; Bonod, Nicolas
2012-08-27
Dielectric particles supporting both magnetic and electric Mie resonances are shown to be able to either reflect or collect the light emitted by a single photon source. An analytical model accurately predicts the scattering behavior of a single dielectric particle electromagnetically coupled to the electric dipole transition moment of a quantum emitter. We derive near field extensions of the Kerker conditions in order to determine the conditions that strongly reduce scattering in either the forward or backward directions. This concept is then employed to design a lossless dielectric collector element whose directivity is boosted by the coherent scattering of both electric and magnetic dipoles. PMID:23037088
8. Induced Magnetic Dipole at Callisto: 3-D Hybrid Modeling of Flybys by Galileo
NASA Astrophysics Data System (ADS)
Holmstrom, M.; Lindkvist, J.; Khurana, K. K.; Fatemi, S.; Barabash, S.
2014-12-01
Modeling the interaction between Callisto and Jupiter's magnetosphere is important to understand the origin of the magnetic field perturbations observed by Galileo, potentially related to subsurface oceans. By using a 3-D hybrid plasma solver, we have varied the induced magnetic dipole responses due to the time-varying magnetic field of the Jovian magnetosphere corresponding to the C3 and C9 flybys by Galileo. The internal conductivity of Callisto has been set to match the induced dipole response. The model is thus including the physics of a time-varying magnetic field and the dynamics of the magnetospheric plasma. We see that the magnetic response by Callisto depends strongly on the magnetospheric plasma environment.
9. Magnetic field distribution of injection chicane dipoles in Spallation Neutron Source accumulator ring
SciTech Connect
Wang, Jian-Guang
2006-01-01
We have performed 3D computing simulations to study the magnetic field distribution of the injection chicane dipoles in the SNS accumulator ring. The simulations yield the performance characteristics of the magnets and generate the magnetic field data in three dimensional grids for further beam tracking study. Based on the simulation data, a 3D multipole expansion of the chicane dipole field, consisting of the generalized gradients and their derivatives, has been made. The harmonic and pseudo-harmonic components in the expansion give much insight into the magnet physics and can fit directly into theoretical frame work of beam optics. The expansion is quasi-analytical by fitting numeric data into interpolation functions. A 5th-order representation of the magnetic field is generated, and the effects of even higher order terms on the field representation are discussed.
10. Quench antenna and fast-motion investigations during training of a 7T dipole magnet
SciTech Connect
Lietzke, A.F.; Benjegerdes, R.; Bish, P.; Krywinski, J.; Scanlan, R.; Schmidt, R.; Taylor, C.
1994-10-17
Equipment was installed to detect fast conductor motion and quench propagation in a 1 meter long superconducting dipole magnet (1) The fast-motion antenna, centered within the bore of the magnet, used three long dipole coils, mounted end-to-end to span the magnet length. Coil signals were nulled against a neighbor to produce low-ripple signals that were sensitive to local flux changes. A low-microphonic signal was used as an event trigger. (2) Nulling improvements were made for the magnets coil-imbalance signals for improved cross-correlation information. (3) A quench-propagation antenna was installed to observe current redistribution during quench propagation. It consisted of quadrupole/sextupole coil sets distributed at three axial locations within the bore of the magnet. Signals were interpreted in terms of the radius, angle, orientation, and rate of change of an equivalent dipole. The magnet was cooled to 1.8K to maximize the number of events. Twenty-four fast-motion events occurred before the first quench. The signals were correlated with the magnet-coil imbalance signals. The quench-propagation antenna was installed for all subsequent quenches. Ramp-rate triggered quenches produced adequate signals for analysis, but pole-turn quenches yielded such small signals that angular localization of a quench was not precise.
11. Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet
SciTech Connect
Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A.F.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.
1999-03-22
A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
12. Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet
SciTech Connect
Chow, K.; Dietderich, D.R.; Gourlay, S.A.; Gupta, R.; Harnden, W.; Lietzke, A. F.; McInturff, A.D.; Millos, G.A.; Morrison, L.; Morrison, M.; Scanlan, R.M.
2000-02-06
A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
13. A proposed method of measuring the electric-dipole moment of the neutron by ultracold neutron interferometry
SciTech Connect
Freedman, M.S.; Peshkin, M.; Ringo, G.R.; Dombeck, T.W.; Los Alamos National Lab., NM )
1989-08-01
The use of an ultracold neutron interferometer incorporating an electrostatic accelerator having a strong electric field gradient to accelerate neutrons by their possible electric dipole moment is proposed as a method of measuring the neutron electric dipole moment. The method appears to have the possibility of extending the sensitivity of the measurement by several orders of magnitude, perhaps to 10{sup -30} e-cm. 9 refs., 3 figs.
14. Development of Magnetometer Based on the Nonlinear Magneto-Optical Rotation Effect Toward the Measurement of the Electron Electric Dipole Moment
NASA Astrophysics Data System (ADS)
Inoue, Takeshi; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Kawamura, H.; Uchiyama, A.; Aoki, T.; Asahi, K.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Nataraj, H. S.; Sato, T.; Shimizu, Y.; Wakasa, T.; Yoshimi, A.; Yoshida, H. P.; Sakemi, Y.
Toward an experimental search for an electron electric dipole moment by using laser cooled francium atoms, a development of a rubidium (Rb) atomic magnetometer based on a nonlinear magneto-optical rotation (NMOR) effect is presented. In order to obtain a narrow linewidth of the NMOR spectrum, a wall relaxation time of a paraffin coated glass cell, which confined the Rb atom, was experimentally confirmed. A residual field inside a magnetic shield was also evaluated.
15. Information Content of the Low-Energy Electric Dipole Strength: Correlation Analysis
SciTech Connect
Reinhard, P.-G.; Nazarewicz, Witold
2013-01-01
Background: Recent experiments on the electric dipole (E1) polarizability in heavy nuclei have stimulated theoretical interest in the low-energy electric dipole strength, both isovector and isoscalar. Purpose: We study the information content carried by the electric dipole strength with respect to isovector and isoscalar indicators characterizing bulk nuclear matter and finite nuclei. To separate isoscalar and isovector modes, and low-energy strength and giant resonances, we analyze the E1 strength as a function of the excitation energy E and momentum transfer q. Methods: We use the self-consistent nuclear density functional theory with Skyrme energy density functionals, augmented by the random phase approximation, to compute the E1 strength and covariance analysis to assess correlations between observables. Calculations are performed for the spherical, doubly magic nuclei 208Pb and 132Sn. Results: We demonstrate that E1 transition densities in the low-energy region below the giant dipole resonance exhibit appreciable state dependence and multinodal structures, which are fingerprints of weak collectivity. The correlation between the accumulated low-energy strength and the symmetry energy is weak, and dramatically depends on the energy cutoff assumed. On the other hand, a strong correlation is predicted between isovector indicators and the accumulated isovector strength at E around 20 MeV and momentum transfer q 0.65 fm 1. Conclusions: Momentum- and coordinate-space patterns of the low-energy dipole modes indicate a strong fragmentation into individual particle-hole excitations. The global measure of low-energy dipole strength correlates poorly with the nuclear symmetry energy and other isovector characteristics. Consequently, our results do not support the suggestion that there exists a collective pygmy dipole resonance, which is a strong indicator of nuclear isovector properties. By considering nonzero values of momentum transfer, one can isolate individual excitations and nicely separate low-energy excitations from the T=1 and T=0 giant collective modes. That is, measurements at q>0 may serve as a tool to correlate the E1 strength with certain bulk observables, such as incompressibility and symmetry energy.
16. Dephasing due to Nuclear Spins in Large-Amplitude Electric Dipole Spin Resonance.
PubMed
Chesi, Stefano; Yang, Li-Ping; Loss, Daniel
2016-02-12
We analyze effects of the hyperfine interaction on electric dipole spin resonance when the amplitude of the quantum-dot motion becomes comparable or larger than the quantum dot's size. Away from the well-known small-drive regime, the important role played by transverse nuclear fluctuations leads to a Gaussian decay with characteristic dependence on drive strength and detuning. A characterization of spin-flip gate fidelity, in the presence of such additional drive-dependent dephasing, shows that vanishingly small errors can still be achieved at sufficiently large amplitudes. Based on our theory, we analyze recent electric dipole spin resonance experiments relying on spin-orbit interactions or the slanting field of a micromagnet. We find that such experiments are already in a regime with significant effects of transverse nuclear fluctuations and the form of decay of the Rabi oscillations can be reproduced well by our theory. PMID:26919009
17. Dephasing due to Nuclear Spins in Large-Amplitude Electric Dipole Spin Resonance
NASA Astrophysics Data System (ADS)
Chesi, Stefano; Yang, Li-Ping; Loss, Daniel
2016-02-01
We analyze effects of the hyperfine interaction on electric dipole spin resonance when the amplitude of the quantum-dot motion becomes comparable or larger than the quantum dot's size. Away from the well-known small-drive regime, the important role played by transverse nuclear fluctuations leads to a Gaussian decay with characteristic dependence on drive strength and detuning. A characterization of spin-flip gate fidelity, in the presence of such additional drive-dependent dephasing, shows that vanishingly small errors can still be achieved at sufficiently large amplitudes. Based on our theory, we analyze recent electric dipole spin resonance experiments relying on spin-orbit interactions or the slanting field of a micromagnet. We find that such experiments are already in a regime with significant effects of transverse nuclear fluctuations and the form of decay of the Rabi oscillations can be reproduced well by our theory.
18. Electric Dipole Aggregates in Very Dilute Polar Liquids:. Theory and Experimental Evidence
NASA Astrophysics Data System (ADS)
Yinnon, Tamar A.; Yinnon, Carmi A.
We show that rotational excited aggregates with an electric dipole moment may be created in polar liquids. Under proper storage conditions, the life times of the aggregates are very long, e.g., days and even years. In solutions, the aggregates are composed of solvent molecules only or a combination of these and solute particles. The process steps leading to the formation of the aggregates are: (1) vigorous succussing the liquid or its solution; (2) adding nonsuccussed liquid; (3) repetition of step (1) and (2). In solutions, formation of the aggregates requires that these steps are repeated until the concentration is reduced below a solvent and solute specific molarity, which under room temperature and pressure conditions, typically, is of the order of 10-4 M or below. The characteristics of liquids containing aggregates with an electric dipole, theoretically derived in this paper, conform to the experimentally observed ones, reported in the literature.
19. Electric dipole moment of the top quark within an effective theory
SciTech Connect
Novales-Sanchez, H.; Toscano, J. J.
2009-04-20
Using the effective Lagrangian approach, we develope the trilinear contributions originated in the dimension-six electroweak invariants O-tilde{sub W} = (1/3){epsilon}{sub ijk}W{sup i{mu}}{sub v}W{sup jv}{sub {lambda}}W{sup k{lambda}}{sub {mu}} and O-tilde{sub WB} = (1/2)B-tilde{sub {alpha}}{sub {beta}}W{sup c{alpha}}{sup {beta}}{phi}{sup {dagger}}{tau}{sup c}{phi}, and then we insert the corresponding vertices in a one-loop ttV diagram, with V off-shell, generating the structure of the electric dipole moment. Using a nonlinear gauge, we prove that the results are gauge independent. Finally, we present the analytic expressions for the electric dipole form factors originated in each invariant introduced.
20. Large tau and tau neutrino electric dipole moments in models with vectorlike multiplets
SciTech Connect
Ibrahim, Tarek; Nath, Pran
2010-02-01
It is shown that the electric dipole moment of the {tau} lepton several orders of magnitude larger than predicted by the standard model can be generated from mixings in models with vectorlike mutiplets. The electric dipole moment (EDM) of the {tau} lepton arises from loops involving the exchange of the W, the charginos, the neutralinos, the sleptons, the mirror leptons, and the mirror sleptons. The EDM of the Dirac {tau} neutrino is also computed from loops involving the exchange of the W, the charginos, the mirror leptons, and the mirror sleptons. A numerical analysis is presented, and it is shown that the EDMs of the {tau} lepton and the {tau} neutrino which lie just a couple of orders of magnitude below the sensitivity of the current experiment can be achieved. Thus the predictions of the model are testable in an improved experiment on the EDM of the {tau} and the {tau} neutrino.
1. Permanent electric dipole moments of alkaline-earth-metal monofluorides: Interplay of relativistic and correlation effects
NASA Astrophysics Data System (ADS)
Prasannaa, V. S.; Sreerekha, S.; Abe, M.; Bannur, V. M.; Das, B. P.
2016-04-01
The interplay of the relativistic and correlation effects in the permanent electric dipole moments of the X 2Σ+ electronic ground states of the alkaline-earth-metal monofluorides (BeF, MgF, CaF, SrF, and BaF) has been studied using a relativistic coupled cluster method. The calculations were carried out using double, triple, and quadruple zeta basis sets, and with no core orbitals frozen. The results are compared with those of other calculations available in the literature and with experiments. The correlation trends in the permanent electric dipole moments of these molecules are discussed in detail. This information will be useful in throwing light on the interplay between relativistic and correlation effects of other properties that are relevant to fundamental physics.
2. Development of cos-theta Nb{sub 3}Sn dipole magnets for VLHC
SciTech Connect
Alexander Zlobin et al.
2001-07-20
This paper describes the double aperture dipole magnets developed for a VLHC based on Nb{sub 3}Sn superconductor, a cos-theta coil, cold and warm iron yokes, and the wind-and-react fabrication technique. Status of the model R and D program, strand and cable and other major component development are also discussed.
3. Charged spinning fluids with magnetic dipole moment in the Einstein-Cartan theory
SciTech Connect
Amorim, R.
1985-06-15
A classical perfect charged spinning fluid with magnetic dipole moment in the Einstein-Cartan theory is described by using an Eulerian Lagrangian formalism. The field equations and equations of motion so obtained generalize those proposed by Ray and Smalley. We also clarify some open questions which appear in the works of Ray and Smalley and of de Ritis et al.
4. Different Paths to Some Fundamental Physical Laws: Relativistic Polarization of a Moving Magnetic Dipole
ERIC Educational Resources Information Center
Kholmetskii, Alexander L.; Yarman, T.
2010-01-01
In this paper we consider the relativistic polarization of a moving magnetic dipole and show that this effect can be understood via the relativistic generalization of Kirchhoff's first law to a moving closed circuit with a steady current. This approach allows us to better understand the law of relativistic transformation of four-current density…
5. Ramp rate sensitivities of several superconducting dipole magnets operated in He I and superfluid He II
SciTech Connect
Caspi, S.; Gilbert, W.S.; Rechen, J.B.
1982-11-01
The quench current of a superconducting dipole magnet decreases from its slow-ramp value as the current ramp-rate is increased, due to heat buildup in the coil winding. This ramp-rate dependence has been measured for several superconducting dipoles in both normal He I and in superfluid He II. The heat generated by charging fields has been measured for severall magnets in He II, where particularly sensitive and accurate measurements can be made of any heat input to the essentially isothermal helium bath by its temperature rise. Previously measured values of heat transfer are applied to the data from one magnet to explain its observed behavior. The conclusion is drawn that at a given cycle rate, a superfluid He II-cooled superconducting accelerator can operate closer to the short-sample limit of the magnet's superconductor than can a corresponding He I-cooled machine.
6. Nonspreading Wave Packets for Rydberg Electrons in Rotating Molecules with Electric Dipole Moments
SciTech Connect
Bialynicki-Birula, I.
1996-11-01
Nonspreading wave packets for Rydberg electrons are predicted in rotating molecules with electric dipole moments. We have named them the Trojan wave packets since their stability is due to the same mechanism that governs the motion of the Trojan asteroids in the Sun-Jupiter system. Unlike all previously predicted Trojan wave packets in atoms, molecular Trojan states do not require external fields for their existence.
7. Exact solution for a noncentral electric dipole ring-shaped potential in the tridiagonal representation
SciTech Connect
Huangfu Guoqing; Zhang Mincang
2011-04-15
The Schroedinger equation with noncentral electric dipole ring-shaped potential is investigated by working in a complete square integrable basis that supports an infinite tridiagonal matrix representation of the wave operator. The three-term recursion relations for the expansion coefficients of both the angular and radial wavefunctions are presented. The discrete spectrum for the bound states is obtained by the diagonalization of the radial recursion relation. Some potential applications of this system in different fields are discussed.
8. Electric dipole transitions for 3d64s-3d64p in Mn I
NASA Astrophysics Data System (ADS)
Kabakçı, Selda; Özdemir, Leyla; Usta, Betül Karaçoban
2015-10-01
We have calculated the logarithmic weighted oscillator strengths and transition probabilities (or rates) for 3d64s-3d64p electric dipole transitions in neutral manganese (Mn I, Z=25) by using two configuration interaction methods (the multiconfiguration Hartree-Fock (MCHF) method within the framework of Breit-Pauli relativistic corrections developed by Fischer and Cowan's relativistic Hartree-Fock (HFR) method). Results obtained have been compared with other calculations and experiments.
9. Experimental search for the electron electric dipole moment with laser cooled francium atoms
NASA Astrophysics Data System (ADS)
Inoue, T.; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Kawamura, H.; Uchiyama, A.; Aoki, T.; Asahi, K.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Nataraj, H. S.; Sato, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Yoshimi, A.; Sakemi, Y.
2015-04-01
A laser cooled heavy atom is one of the candidates to search for the permanent electric dipole moment (EDM) of the electron due to the enhancement mechanism and its long coherence time. The laser cooled francium (Fr) factory has been constructed to perform the electron EDM search at the Cyclotron and Radioisotope Center, Tohoku University. The present status of Fr production and the EDM measurement system is presented.
10. Development of francium atomic beam for the search of the electron electric dipole moment
NASA Astrophysics Data System (ADS)
Sato, Tomoya; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Inoue, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Kato, T.; Kawamura, H.; Nataraj, H. S.; Uchiyama, A.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.
2014-03-01
For the measurement of the electron electric dipole moment using Fr atoms, a Fr ion-atom conversion is one of the most critical process. An ion-atom converter based on the "orthotropic" type of Fr source has been developed. This converter is able to convert a few keV Fr ion beam to a thermal atomic beam using a cycle of the surface ionization and neutralization. In this article, the development of the converter is reported.
11. Low lying electric dipole excitations in nuclei of the rare earth region
SciTech Connect
von Brentano, P.; Zilges, A.; Herzberg, R.D. . Inst. fuer Kernphysik); Zamfir, N.V. ); Kneissl, U.; Heil, R.D.; Pitz, H.H. . Inst. fuer Strahlenphysik); Wesselborg, C. . Inst. fuer Kernphysik)
1992-01-01
From many experiments with low energy photon scattering on deformed rare earth nuclei we have obtained detailed information about the distribution of electric dipole strength below 4 MeV. Apart from some weaker transitions between 2 and 4 MeV we observed one, and sometimes two, very strong El-groundstate transitions around 1.5 MeV in all examined nuclei. They arise from the de-excitation of the bandheads of the (J[sup [pi
12. Shell model estimate of electric dipole moment in medium and heavy nuclei
SciTech Connect
Yoshinaga, Naotaka; Higashiyama, Koji
2011-05-06
The nuclear electric dipole moment (EDM) and the nuclear Schiff moment for the lowest 1/2{sup +} state of {sup 129}Xe are investigated in terms of the nuclear shell model. We estimate the upper limit for the EDM of neutral {sup 129}Xe atom using the Schiff moment. We also estimate the upper limit of the nuclear EDM, which may be directly measured through ionic atoms.
13. Resonance Method of Electric-Dipole-Moment Measurements in Storage Rings
SciTech Connect
Orlov, Yuri F.; Morse, William M.; Semertzidis, Yannis K.
2006-06-02
A 'resonance method' of measuring the electric dipole moment (EDM) of nuclei in storage rings is described, based on two new ideas: (1) Oscillating particles' velocities in resonance with spin precession, and (2) alternately producing two sub-beams with different betatron tunes--one sub-beam to amplify and thus make it easier to correct ring imperfections that produce false signals imitating EDM signals, and the other to make the EDM measurement.
14. RESONANCE METHOD OF ELECTRIC-DIPOLE-MOMENT MEASUREMENTS IN STORAGE RINGS.
SciTech Connect
ORLOV, Y.F.; MORSE, W.M.; SEMERTZIDIS, Y.K.
2006-05-10
A ''resonance method'' of measuring the electric dipole moment (EDM) of nuclei in storage rings is described, based on two new ideas: (1) Oscillating particles velocities in resonance with spin precession, and (2) alternately producing two sub-beams with different betatron tunes--one sub-beam to amplify and thus make it easier to correct ring imperfections that produce false signals imitating EDM signals, and the other to make the EDM measurement.
15. Torque for electron spin induced by electron permanent electric dipole moment
SciTech Connect
Senami, Masato E-mail: [email protected]; Fukuda, Masahiro E-mail: [email protected]; Ogiso, Yoji E-mail: [email protected]; Tachibana, Akitomo E-mail: [email protected]
2014-10-06
The spin torque of the electron is studied in relation to the electric dipole moment (EDM) of the electron. The spin dynamics is known to be given by the spin torque and the zeta force in quantum field theory. The effect of the EDM on the torque of the spin brings a new term in the equation of motion of the spin. We study this effect for a solution of the Dirac equation with electromagnetic field.
16. Tables of branching ratios for electric dipole transitions between arbitrary levels of hydrogen-like atoms
NASA Technical Reports Server (NTRS)
Omidvar, K.
1977-01-01
The branching ratios in hydrogen-like atoms due to the electric-dipole transitions are tabulated for the initial principal and azimuthal quantum numbers n prime l prime, and final principal and azimuthal quantum numbers n l. Average values with respect to l prime are given. The branching ratios not tabulated, including the initial states n prime yields infinity l prime corresponding to the threshold of the continuum, could be obtained by extrapolation.
17. Supercriticality of novel type induced by electric dipole in gapped graphene
NASA Astrophysics Data System (ADS)
Gorbar, E. V.; Gusynin, V. P.; Sobol, O. O.
2015-12-01
We reveal a new type of supercritical behavior in gapped graphene with two oppositely charged impurities by studying the two-dimensional Dirac equation for quasiparticles with the Coulomb potential regularized at small distances accounting the lattice effects. By utilizing the variational Galerkin-Kantorovich method, we show that for supercritical electric dipole the wave function of the electron bound state changes its localization from the negatively charged impurity to the positively charged one as the distance between the impurities changes. Such a migration of the wave function corresponds to the electron and hole spontaneously created from the vacuum in bound states screening the positively and negatively charged impurities of the supercritical electric dipole, respectively. We generalize our results to a particle-hole asymmetric case, where the charges of impurities differ in signs and absolute values, and demonstrate that the necessary energetic condition for the supercriticality of novel type to occur is that the energy levels of single positively and negatively charged impurities traverse together the energy distance separating the upper and lower continua. The robustness of the supercriticality of novel type is confirmed by the study of an exactly solvable one-dimensional problem of the Dirac equation with the square well and barrier potential modeling an electric-dipole potential.
18. Neutron electric dipole moment using Nf=2 +1 +1 twisted mass fermions
NASA Astrophysics Data System (ADS)
Alexandrou, C.; Athenodorou, A.; Constantinou, M.; Hadjiyiannakou, K.; Jansen, K.; Koutsou, G.; Ottnad, K.; Petschlies, M.
2016-04-01
We evaluate the neutron electric dipole moment |d→ N| using lattice QCD techniques. The gauge configurations analyzed are produced by the European Twisted Mass Collaboration using Nf=2 +1 +1 twisted mass fermions at one value of the lattice spacing of a ≃0.082 fm and a light quark mass corresponding to mπ≃373 MeV . Our approach to extract the neutron electric dipole moment is based on the calculation of the C P -odd electromagnetic form factor F3(Q2) for small values of the vacuum angle θ in the limit of zero Euclidean momentum transfer Q2. The limit Q2→0 is realized either by adopting a parametrization of the momentum dependence of F3(Q2) and performing a fit or by employing new position space methods, which involve the elimination of the kinematical momentum factor in front of F3(Q2). The computation in the presence of a C P -violating term requires the evaluation of the topological charge Q . This is computed by applying the cooling technique and the gradient flow with three different actions, namely the Wilson, the Symanzik tree-level improved and the Iwasaki action. We demonstrate that cooling and gradient flow give equivalent results for the neutron electric dipole moment. Our analysis yields a value of |d→ N|=0.045 (6 )(1 )θ ¯ e .fm for the ensemble with mπ=373 MeV considered.
19. Observation of Centrifugally Driven Interchange Instabilities in a Plasma Confined by a Magnetic Dipole
SciTech Connect
Levitt, B.; Maslovsky, D.; Mauel, M.E.
2005-05-06
Centrifugally driven interchange instabilities are observed in a laboratory plasma confined by a dipole magnetic field. The instabilities appear when an equatorial mesh is biased to drive a radial current that causes rapid axisymmetric plasma rotation. The observed instabilities are quasicoherent in the laboratory frame of reference; they have global radial mode structures and low azimuthal mode numbers, and they are modified by the presence of energetic, magnetically confined electrons. Results from a self-consistent nonlinear simulation reproduce the measured mode structures.
20. Design of Racetrack Coils for High Field Dipole Magnets
SciTech Connect
Sabbi, G.; Caspi, S.; Gourlay, S.A.; Hafalia, R.; Jackson, A.; Lietzke, A.; McInturff, A.D.; Scanlan, R.M.
2000-09-08
The magnet group at LBNL is currently in the process of developing high-field accelerator magnets for use in future colliders. One of the primary challenges is to provide a design which is cost-effective and simple to manufacture, at the same time resulting in good training performance and field quality adequate for accelerator operation. Recent studies have focused on a racetrack geometry that has the virtues of simplicity and conductor compatibility. The results have been applied to the design of a series of prototype high-field magnets based on Nb{sub 3}Sn conductor.
1. Structural performance of the first SSC (Superconducting Super Collider) Design B dipole magnet
SciTech Connect
Nicol, T.H.
1989-09-01
The first Design B Superconducting Super Collider (SSC) dipole magnet has been successfully tested. This magnet was heavily instrumented with temperature and strain gage sensors in order to evaluate its adherence to design constraints and design calculations. The instrumentation and associated data acquisition system allowed monitoring of the magnet during cooldown, warmup, and quench testing. This paper will focus on the results obtained from structural measurements on the suspension system during normal and rapid cooldowns and during quench studies at full magnet current. 4 refs., 9 figs.
2. Modeling the magnetic field of Mercury using the Time Dependent Equivalent Source Dipole method
NASA Astrophysics Data System (ADS)
Oliveira, Joana; Langlais, Benoit; Amit, Hagay; Pais, Maria Alexandra
2014-05-01
We introduce the Time Dependent Equivalent Source Dipole (TD-ESD) method developed with the purpose of modeling the Hermean magnetic field. It takes into account the partial orbital coverage provided by MErcury Surface, Space ENvironment, Geochemistry, and Ranging (MESSENGER) mission. The TD-ESD method is based on the Equivalent Source Dipole approach, which has been largely used to downward or upward continue to constant altitude measurements of magnetic fields of crustal origin, on local or global scale. In this present application to Mercury, for which an internal core field is expected, the dipoles are uniformly distributed at a spherical surface placed deep into the planet's interior. Both their magnitude and directions are not a priori imposed and are free to evolve with time. Using synthetic data generated at MESSENGER orbit positions we successfully recover the three components of the magnetic field. We also recover the temporal variation that we a priori imposed. We find that downward and upward continuation is possible over a certain limited region. The resulting field is within 6% of the initial field for altitudes ranging between -100km and 1500km. Here we present the first constant altitude magnetic field maps derived from MESSENGER measurements acquired during the first mercury's solar day. We identify a strong time dependent signature of the external magnetic field, even when only measurements over the northern hemisphere below ~1000 km altitude are used. A future improvement of the method will consist in the simultaneous analysis of the external and internal magnetic fields.
3. Near-field characteristics of electric dipole antennas in the inner magnetosphere
NASA Astrophysics Data System (ADS)
Chevalier, Timothy W.
Electric dipole antennas are commonly used in space plasmas with applications that range from radio frequency probing of the magnetosphere to plasma diagnostics. With the recent interest in the in-situ injection of ELF/VLF waves for the study of magnetospheric wave-particle interactions, the characterization of the antenna-plasma coupling behavior in this regime is of primary importance. The coupling considered in this dissertation occurs in an operating environment that corresponds to magnetospheric conditions found between L=2 and L=3 in the geomagnetic equatorial plane. The near field of the antenna consists of a plasma sheath which directly affects the terminal impedance properties. Inside the sheath region, the plasma dynamics are highly nonlinear and must be solved numerically. In order to optimally inject VLF waves and thereby maximize the antenna-plasma coupling response, it is necessary to determine the characteristics of electric dipole antennas operating within this region of space. This dissertation addresses the efficacy of using electric dipole antennas as in-situ wave injection instruments and focuses on the near-field coupling of these antennas to the environment in which they are immersed. A two-tiered hydrodynamic approach has been developed to solve for the plasma dynamics in the region surrounding the antenna. First, a three-dimensional full wave solution of Maxwell's equations is implemented to simulate the current distribution and input impedance of an electric dipole antenna operating in a cold magnetoplasma at VLF. It is shown that the current distribution for antennas with length <100 m is approximately triangular for magnetospheric conditions considered herein. Calculated variations of input impedance as a function of drive frequency are presented for two case studies and compared with predictions of existing analytical work. This model is then extended to include finite temperature effects allowing for the determination of the sheath characteristics as a function of drive frequency and voltage. The primary assumptions underlying the closure mechanisms for the infinite set of fluid moments are examined through theoretical observations and simulated comparisons of the various truncation schemes. Results from these two models allow for the complete characterization of the near-field properties of electric dipole antennas operating in this highly anisotropic environment.
4. Quark loop contributions to neutron, deuteron, and mercury electric dipole moments from supersymmetry without R parity
NASA Astrophysics Data System (ADS)
Chiou, Chan-Chi; Kong, Otto C. W.; Vaidya, Rishikesh D.
2007-07-01
We present a detailed analysis together with numerical calculations on one-loop contributions to the neutron, deuteron, and mercury electric dipole moment from supersymmetry without R parity, focusing on the quark-scalar loop contributions. Being proportional to top Yukawa and top mass, such contributions are often large, and since these are proportional to hitherto unconstrained combinations of bilinear and trilinear R-parity violating (RPV) parameters, they are all the more interesting. Complete formulas are given for the various contributions through the quark dipole operators including the contribution from the color dipole operator. The contribution from the color dipole operator is found to be a similar order in magnitude when compared to the electric dipole operator and should be included in any consistent analysis. Analytical expressions illustrating the explicit role of the R-parity violating parameters are given following perturbative diagonalization of mass-squared matrices for the scalars. Dominant contributions come from the combinations Bi*λij1' for which we obtain robust bounds. It turns out that neutron and deuteron electric dipole moments (EDMs) receive much stronger contributions than the mercury EDM and any null result at the future deuteron EDM experiment or Los Alamos neutron EDM experiment can lead to extraordinary constraints on RPV parameter space. Even if R-parity violating couplings are real, Cabibbo-Kobayashi-Maskawa (CKM) phase does induce RPV contribution and for some cases such a contribution is as strong as the contribution from phases in the R-parity violating couplings. Hence, we have bounds directly on |Bi*λij1'| even if the RPV parameters are all real. Interestingly, even if slepton mass and/or μ0 is as high as 1 TeV, it still leads to neutron EDM that is an order of magnitude larger than the sensitivity at the Los Alamos experiment. Since the results are not much sensitive to tanβ, our constraints will survive even if other observables tighten the constraints on tanβ.
5. Electric/magnetic dipolein an electromagnetic field: force, torque and energy
NASA Astrophysics Data System (ADS)
Kholmetskii, Alexander; Missevitch, Oleg; Yarman, T.
2014-10-01
In this paper we collect the relativistic expressions for the force, torque and energy of a small electric/magnetic dipole in an electromagnetic field, which we recently obtained (A.L. Kholmetskii et al., Eur. J. Phys. 33, L7 (2011), Prog. Electromagn. Res. B 45, 83 (2012), Can. J. Phys. 9, 576 (2013)) and consider a number of subtle effects, characterized the behavior of the dipole in an external field, which seem interesting from the practical viewpoint.
6. Studies of time dependence of fields in TEVATRON superconducting dipole magnets
SciTech Connect
Hanft, R.W.; Brown, B.C.; Herrup, D.A.; Lamm, M.J.; McInturff, A.D.; Syphers, M.J.
1988-08-22
The time variation in the magnetic field of a model Tevatron dipole magnet at constant excitation current has been studied. Variations in symmetry allowed harmonic components over long time ranges show a log t behavior indicative of ''flux creep.'' Both short time range and long time range behavior depend in a detailed way on the excitation history. Similar effects are seen in the remnant fields present in full-scale Tevatron dipoles following current ramping. Both magnitudes and time dependences are observed to depend on details for the ramps, such as ramp rate, flattop duration, and number of ramps. In a few magnets, variations are also seen in symmetry unallowed harmonics. 9 refs., 10 figs.
7. Magnetic design and field optimization of a superferric dipole for the RISP fragment separator
NASA Astrophysics Data System (ADS)
Zaghloul, A.; Kim, J. Y.; Kim, D. G.; Jo, H. C.; Kim, M. J.
2015-10-01
The in-flight fragment separator of the Rare Isotope Science Project requires eight dipole magnets to produce a gap field of 1.7 T in a deflection sector of 30 degree with a 6-m central radius. If the beam-optics requirements are to be met, an integral field homogeneity of a few units (1 unit = 10-4) must be achieved. A superferric dipole magnet has been designed by using the Low-Temperature Superconducting wire NbTi and soft iron of grade SAE1010. The 3D magnetic design and field optimization have been performed using the Opera code. The length and the width of the air slots in the poles have been determined in an optimization process that considered not only the uniformity of the field in the straight section but also the field errors in the end regions. The field uniformity has also been studied for a range of operation of the dipole magnet from 0.4 T to 1.7 T. The magnetic design and field uniformity are discussed.
8. Magnetic and structural design of a 15 T Nb3Sn accelerator dipole model
NASA Astrophysics Data System (ADS)
Kashikhin, V. V.; Andreev, N.; Barzi, E.; Novitski, I.; Zlobin, A. V.
2015-12-01
Hadron Colliders (HC) are the most powerful discovery tools in modern high energy physics. A 100 TeV scale HC with a nominal operation field of at least 15 T is being considered for the post-LHC era. The choice of a 15 T nominal field requires using the Nb3Sn technology. Practical demonstration of this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are the key conditions for realization of such a machine. FNAL has started the development of a 15 T Nb3Sn dipole demonstrator for a 100 TeV scale HC. The magnet design is based on 4-layer shell type coils, graded between the inner and outer layers to maximize the performance. The experience gained during the 11-T dipole R&D campaign is applied to different aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T Nb3Sn dipole and the steps towards the demonstration model.
9. Search for a Permanent Electric Dipole Moment of the Mercury Atom
SciTech Connect
Fortson, E. N.
2009-12-17
There has been exciting progress in recent years in the search for a permanent electric dipole moment (EDM) of an atom, a molecule, or the neutron. An EDM along the axis of spin can exist only if time reversal symmetry (T) is violated. Although such a dipole has not yet been detected, mainstream theories of possible new physics, such as Supersymmetry, predict the existence of EDMs within reach of modern experiments. Here I discuss the results of our new experimental search for a permanent electric dipole moment of {sup 199}Hg utilizing a stack of four vapor cells. We find d({sup 199}Hg) (0.49{+-}1.29{sub stat}{+-}0.76{sub syst})x10{sup -29} e cm, and interpret this as a new upper bound, d({sup 199}Hg)<3.1x10{sup -29} e cm(95% C.L.). This result improves our previous {sup 199}Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the Standard Model.
10. Tests of 40 mm SSC dipole model magnets with vertically split yokes
SciTech Connect
Koska, W.; Bossert, R.; Coulter, K.J.; Delchamps, S.; Gourlay, S.; Kinney, W.; Jaffery, T.S.; Lamm, M.J.; Strait, J.; Wake, M.
1991-05-01
Several 1 meter long, 40 mm aperture model SSC dipole magnets with vertically split yokes have been built and tested at Fermilab. In addition to the yoke design, these magnets were used to evaluate several variants of the collet clamps which apply prestress to the magnet ends. The magnets were instrumented with voltage taps for quench localization and strain gage based devices for measuring stresses, forces and deflections resulting from cooldown and excitation. Test were carried out in a vertical dewar at temperatures from 3.8{degree}K to 4.4{degree}K. The quench and mechanical behavior of these magnets will be presented and magnetic field measurements will be shown. A comparison with an earlier series of magnets with horizontally split yokes will be made. 7 refs., 4 figs., 1 tab.
11. Modeling the magnetic field of Mercury using the Time Dependent Equivalent Source Dipole method
NASA Astrophysics Data System (ADS)
Oliveira, J. S.; Langlais, B.; Amit, H.; Pais, M. A.
2013-12-01
We introduce the Time Dependent Equivalent Source Dipole (TD-ESD) method developed with the purpose of modeling the Hermean magnetic field, taking into account the partial orbital coverage provided by MErcury Surface, Space ENvironment, Geochemistry, and Ranging (MESSENGER) mission. The TD-ESD method is based on the Equivalent Source Dipole approach, which has been largely used to downward or upward continue to constant altitude measurements of magnetic fields of crustal origin, on local or global scale. In this present application to Mercury, for which an internal core field is expected, the dipoles are uniformly distributed in a spherical shell placed deep into the planet's interior; their magnitude and direction are free to evolve with time. We ran several tests in order to validate the new method. We successfully recover the three components of the synthetic Hermean magnetic field. We also recover the temporal variation that we a priori imposed. Using synthetic data generated at MESSENGER orbit positions we find that downward and upward continuation is possible over a certain delimited region. When the dipole layer is placed at a depth of 640 km below the planet's surface, the resulting field is within 6% of the initial field model for altitudes ranging between -100km and 1500km. Here we present constant altitude magnetic field maps derived from MESSENGER measurements acquired during the first solar mercury year. We identify a strong signature of the external magnetic field, even when only measurements over the northern hemisphere below ~1000 km altitude are used. A future improvement of the method will consist in the simultaneous analysis of the external and internal magnetic fields.
12. Electric dipole moment planning with a resurrected BNL Alternating Gradient Synchrotron electron analog ring
NASA Astrophysics Data System (ADS)
Talman, Richard M.; Talman, John D.
2015-07-01
There has been much recent interest in directly measuring the electric dipole moments (EDM) of the proton and the electron, because of their possible importance in the present day observed matter/antimatter imbalance in the Universe. Such a measurement will require storing a polarized beam of "frozen spin" particles, 15 MeV electrons or 230 MeV protons, in an all-electric storage ring. Only one such relativistic electric accelerator has ever been built—the 10 MeV "electron analog" ring at Brookhaven National Laboratory in 1954; it can also be referred to as the "AGS analog" ring to make clear it was a prototype for the Alternating Gradient Synchrotron (AGS) proton ring under construction at that time at BNL. (Its purpose was to investigate nonlinear resonances as well as passage through "transition" with the newly invented alternating gradient proton ring design.) By chance this electron ring, long since dismantled and its engineering drawings disappeared, would have been appropriate both for measuring the electron EDM and to serve as an inexpensive prototype for the arguably more promising, but 10 times more expensive, proton EDM measurement. Today it is cheaper yet to "resurrect" the electron analog ring by simulating its performance computationally. This is one purpose for the present paper. Most existing accelerator simulation codes cannot be used for this purpose because they implicitly assume magnetic bending. The new ual/eteapot code, described in detail in an accompanying paper, has been developed for modeling storage ring performance, including spin evolution, in electric rings. Illustrating its use, comparing its predictions with the old observations, and describing new expectations concerning spin evolution and code performance, are other goals of the paper. To set up some of these calculations has required a kind of "archeological physics" to reconstitute the detailed electron analog lattice design from a 1991 retrospective report by Plotkin as well as unpublished notes of Courant describing machine studies performed in 1954-1955. This paper describes the practical application of the eteapot code and provides sample results, with emphasis on emulating lattice optics in the AGS analog ring for comparison with the historical machine studies and to predict the electron spin evolution they would have measured if they had polarized electrons and electron polarimetry. Of greater present day interest is the performance to be expected for a proton storage ring experiment. To exhibit the eteapot code performance and confirm its symplecticity, results are also given for 30 million turn proton spin tracking in an all-electric lattice that would be appropriate for a present day measurement of the proton EDM. The accompanying paper "Symplectic orbit and spin tracking code for all-electric storage rings" documents in detail the theoretical formulation implemented in eteapot, which is a new module in the Unified Accelerator Libraries (ual) environment.
13. Location and depth estimation of point-dipole and line of dipoles using analytic signals of the magnetic gradient tensor and magnitude of vector components
NASA Astrophysics Data System (ADS)
Oruç, Bülent
2010-01-01
The magnetic gradient tensor (MGT) provides gradient components of potential fields with mathematical properties which allow processing techniques e.g. analytic signal techniques. With MGT emerging as a new tool for geophysical exploration, the mathematical modelling of gradient tensor fields is necessary for interpretation of magnetic field measurements. The point-dipole and line of dipoles are used to approximate various magnetic objects. I investigate the maxima of the magnitude of magnetic vector components (MMVC) and analytic signals of magnetic gradient tensor (ASMGT) resulting from point-dipole and line of dipoles sources in determining horizontal locations. I also present a method in which depths of these sources are estimated from the ratio of the maximum of MMVC to the maximum of ASMGT. Theoretical examples have been carried out to test the feasibility of the method in obtaining source locations and depths. The method has been applied to the MMVC and ASMGT computed from the total field data over a basic/ultrabasic body at the emerald deposit of Socotó, Bahia, Brazil and buried water supply pipe near Jadaguda Township, India. In both field examples, the method produces good correlations with previous interpretations.
14. Hyperfine interaction mediated electric-dipole spin resonance: the role of frequency modulation
NASA Astrophysics Data System (ADS)
Li, Rui
2016-05-01
The electron spin in a semiconductor quantum dot can be coherently controlled by an external electric field, an effect called electric-dipole spin resonance (EDSR). Several mechanisms can give rise to the EDSR effect, among which there is a hyperfine mechanism, where the spin-electric coupling is mediated by the electron–nucleus hyperfine interaction. Here, we investigate the influence of frequency modulation (FM) on the spin-flip efficiency. Our results reveal that FM plays an important role in the hyperfine mechanism. Without FM, the electric field almost cannot flip the electron spin the spin-flip probability is only about 20%. While under FM, the spin-flip probability can be improved to approximately 70%. In particular, we find that the modulation amplitude has a lower bound, which is related to the width of the fluctuated hyperfine field.
15. Progress toward a measurement of the electron's electric dipole moment using PbO
NASA Astrophysics Data System (ADS)
Eckel, Stephen; Hamilton, Paul; Kirilov, Emil; Smith, Hunter; Demille, David
2012-06-01
Searches for permanent electric dipole moments (EDMs) of fundamental particles provide a way to detect new sources of time-reversal symmetry violation. We present recent results on an experiment to search for the electron's EDM, using the polar molecule PbO. PbO offers several advantages compared to atoms, including a much larger effective internal electric field (>10 GV/cm) and parity doubling, which can be used to reverse the effective internal electric field without reversing the laboratory electric field. This technique allows for significant rejection of systematic errors. Recent improvements to the experiment have resulted in statistical sensitivities of approximately 1 x10-27 ecm/?day, which could allow for an improvement over the current experimental limit on the electron EDM in only a few days of integration time. Details of the approach and studies of possible systematic errors will be described.
16. Fabrication and component testing results for a Nb{sub 3}Sn dipole magnet
SciTech Connect
DellOrco, D.; Scanlan, R.M.; Taylor, C.E.; Lietzke, A.; Caspi, S.; van Oort, J.M.; McInturff, A.D.
1994-10-01
At present, the maximum field achieved in accelerator R&D dipoles is slightly over 10T, with NbTi conductor at 1.8 K. Although Nb{sub 3}Sn has the potential to achieve much higher fields, none of the previous dipoles constructed from Nb{sub 3}Sn have broken the 10T barrier. We report here on the construction of a dipole with high current density Nb{sub 3}Sn with a predicted short sample limit of 13T. A wind and react technique, followed by epoxy impregnation of the fiberglass insulated coils, was used. The problems identified with the use of Nb{sub 3}SD in earlier dipole magnets were investigated in a series of supplemental tests. This includes measurement of the degradation of J{sub c} with transverse strain, cabling degradation, joint resistance measurements, and epoxy strength tests. In addition, coff assembly techniques were developed to ensure that adequate prestress could be applied without damaging the reacted Nb{sub 3}Sn cable. We report here the results of these tests and the construction status of this 50 mm bore dipole.
17. Vanishing of dipole matrix elements at level crossings.
NASA Technical Reports Server (NTRS)
Kocher, C. A.
1972-01-01
Demonstration that the vanishing of certain coupling matrix elements at level crossings follow from angular momentum commutation relations. A magnetic dipole transition having delta M = plus or minus 1, induced near a crossing of the levels in a nonzero magnetic field, is found to have a dipole matrix element comparable to or smaller than the quotient of the level separation and the field. This result also applies in the analogous electric field electric dipole case.
18. Observation of CS Trilobite Molecules with Kilo-Debye Molecular Frame Permanent Electric Dipole Moments
NASA Astrophysics Data System (ADS)
Shaffer, James P.
2015-06-01
We present results on Cs ultracold Rydberg atom experiments involving trilobite and butterfly molecules. Trilobite molecules are predicted to have giant, body-fixed permanent dipole moments, on the order of 1000 Debye. We present spectra for nS1/2+6S1/2 ^3σ^+ molecules, where n=37, 39 and 40, and measurements of the Stark broadenings of selected trilobite states in Cs due to the application of a constant external electric field. These results show that for Cs, because of its near integer s-state quantum defect, it is possible to photoassociate molecules whose wavefunction is predominantly of trilobite character yielding molecular frame dipole moments of around 2000 Debye. In addition, we have also recently observed states whose spectra show characteristics of p-wave dominated butterfly states. The work on what we believe to be the butterfly states will be compared and contrasted to the measurements of the trilobite states.
19. Preliminary results from a study of collar lamination variation in SSC Prototype Dipole Magnets
SciTech Connect
Gattu, R.; Brown, G.M.; Pollock, D.
1993-04-01
The collar laminations used in SSC Prototype Collider Dipole Magnets determine the volume within which the magnet coils are constrained after collaring and keying. The uniformity and symmetry of the inside volume of the collars along the length of the magnet may have a significant influence on the field quality of the finished assembly. This paper describes an on-going Statistical Quality Control study of collar lamination dimensional variation being performed by SSCL Magnet Systems Division Quality Assurance. Samples of collars have been measured using a coordinate measuring machine evaluate manufacturing process capability as well as the overall uniformity of the inventory population of collar laminations. The collar data will be used to predict variation in the coil assembly center and radius for inner and outer top-bottom, left-right coil combinations well as pole angles. Collar results will be combined with azimuthal coil size measurements part of a manufacturing cause and effect model for predicting axial geometric multipoles based on the observed mechanical variation. This work focuses on Prototype Collider Dipole Magnet DCA 102 currently being built at the SSCL MDL in Waxahachie, Texas. This magnet is being made on the same coil curing and collaring mold cavities that were used for the DCA 300 series magnets built at FNAL in 1991--1992 and which were later used in the 1992 Accelerator Systems String Test (ASST). The collars are part of the same procurement used for the DCA300 series magnets.
20. Is the Non-Dipole Magnetic Field Random?
NASA Technical Reports Server (NTRS)
Walker, Andrew D.; Backus, George E.
1996-01-01
Statistical modelling of the Earth's magnetic field B has a long history. In particular, the spherical harmonic coefficients of scalar fields derived from B can be treated as Gaussian random variables. In this paper, we give examples of highly organized fields whose spherical harmonic coefficients pass tests for independent Gaussian random variables. The fact that coefficients at some depth may be usefully summarized as independent samples from a normal distribution need not imply that there really is some physical, random process at that depth. In fact, the field can be extremely structured and still be regarded for some purposes as random. In this paper, we examined the radial magnetic field B(sub r) produced by the core, but the results apply to any scalar field on the core-mantle boundary (CMB) which determines B outside the CMB.
1. When electric charge becomes also magnetic
NASA Astrophysics Data System (ADS)
Adorno, T. C.; Gitman, D. M.; Shabad, A. E.
2015-08-01
In nonlinear electrodynamics, QED included, we find a static solution to the field equations with an electric charge as its source, which is comprised of homogeneous parallel magnetic and electric fields, and a radial spherically nonsymmetric long-range magnetic field, whose magnetic charge is proportional to the electric charge and also depends on the homogeneous component of the solution.
2. Patterned time-orbiting potentials for the confinement and assembly of magnetic dipoles
PubMed Central
Chen, A.; Sooryakumar, R.
2013-01-01
We present an all-magnetic scheme for the assembly and study of magnetic dipoles within designed confinement profiles that are activated on micro-patterned permalloy films through a precessing magnetic field. Independent control over the confinement and dipolar interactions is achieved by tuning the strength and orientation of the revolving field. The technique is demonstrated with superparamagnetic microspheres field-driven to assemble into closely packed lattice sheets, quasi-1D and other planar structures expandable into dipolar arrays that mirror the patterned surface motifs. PMID:24185093
3. Real-Time Localization of Moving Dipole Sources for Tracking Multiple Free-Swimming Weakly Electric Fish
PubMed Central
Jun, James Jaeyoon; Longtin, André; Maler, Leonard
2013-01-01
In order to survive, animals must quickly and accurately locate prey, predators, and conspecifics using the signals they generate. The signal source location can be estimated using multiple detectors and the inverse relationship between the received signal intensity (RSI) and the distance, but difficulty of the source localization increases if there is an additional dependence on the orientation of a signal source. In such cases, the signal source could be approximated as an ideal dipole for simplification. Based on a theoretical model, the RSI can be directly predicted from a known dipole location; but estimating a dipole location from RSIs has no direct analytical solution. Here, we propose an efficient solution to the dipole localization problem by using a lookup table (LUT) to store RSIs predicted by our theoretically derived dipole model at many possible dipole positions and orientations. For a given set of RSIs measured at multiple detectors, our algorithm found a dipole location having the closest matching normalized RSIs from the LUT, and further refined the location at higher resolution. Studying the natural behavior of weakly electric fish (WEF) requires efficiently computing their location and the temporal pattern of their electric signals over extended periods. Our dipole localization method was successfully applied to track single or multiple freely swimming WEF in shallow water in real-time, as each fish could be closely approximated by an ideal current dipole in two dimensions. Our optimized search algorithm found the animal’s positions, orientations, and tail-bending angles quickly and accurately under various conditions, without the need for calibrating individual-specific parameters. Our dipole localization method is directly applicable to studying the role of active sensing during spatial navigation, or social interactions between multiple WEF. Furthermore, our method could be extended to other application areas involving dipole source localization. PMID:23805244
4. Dual AC Dipole Excitation for the Measurement of Magnetic Multipole Strength from Beam Position Monitor Data
SciTech Connect
M. Spata, G.A. Krafft
2011-09-01
An experiment was conducted at Jefferson Lab's Continuous Electron Beam Accelerator Facility to develop a technique for characterizing the nonlinear fields of the beam transport system. Two air-core dipole magnets were simultaneously driven at two different frequencies to provide a time-dependent transverse modulation of the electron beam. Fourier decomposition of beam position monitor data was then used to measure the amplitude of these frequencies at different positions along the beamline. For a purely linear transport system one expects to find solely the frequencies that were applied to the dipoles with amplitudes that depend on the phase advance of the lattice. In the presence of nonlinear fields one expects to also find harmonics of the driving frequencies that depend on the order of the nonlinearity. The technique was calibrated using one of the sextupole magnets in a CEBAF beamline and then applied to a dipole to measure the sextupole and octupole strength of the magnet. A comparison is made between the beam-based measurements, results from TOSCA and data from our Magnet Measurement Facility.
5. Production and study of high-beta plasma confined by a superconducting dipole magnet
SciTech Connect
Garnier, D.T.; Hansen, A.; Mauel, M.E.; Ortiz, E.; Boxer, A.C.; Ellsworth, J.; Karim, I.; Kesner, J.; Mahar, S.; Roach, A.
2006-05-15
The Levitated Dipole Experiment (LDX) [J. Kesner et al., in Fusion Energy 1998, 1165 (1999)] is a new research facility that is exploring the confinement and stability of plasma created within the dipole field produced by a strong superconducting magnet. Unlike other configurations in which stability depends on curvature and magnetic shear, magnetohydrodynamic stability of a dipole derives from plasma compressibility. Theoretically, the dipole magnetic geometry can stabilize a centrally peaked plasma pressure that exceeds the local magnetic pressure ({beta}>1), and the absence of magnetic shear allows particle and energy confinement to decouple. In initial experiments, long-pulse, quasi-steady-state microwave discharges lasting more than 10 s have been produced that are consistent with equilibria having peak beta values of 20%. Detailed measurements have been made of discharge evolution, plasma dynamics and instability, and the roles of gas fueling, microwave power deposition profiles, and plasma boundary shape. In these initial experiments, the high-field superconducting floating coil was supported by three thin supports. The plasma is created by multifrequency electron cyclotron resonance heating at 2.45 and 6.4 GHz, and a population of energetic electrons, with mean energies above 50 keV, dominates the plasma pressure. Creation of high-pressure, high-beta plasma is possible only when intense hot electron interchange instabilities are stabilized by sufficiently high background plasma density. A dramatic transition from a low-density, low-beta regime to a more quiescent, high-beta regime is observed when the plasma fueling rate and confinement time become sufficiently large.
6. Dipole magnetic-field disturbance and generation of current systems by asymmetric plasma pressure
NASA Astrophysics Data System (ADS)
Vovchenko, V. V.; Antonova, E. E.
2014-03-01
Nonlinear disturbance of the dipole field by nonaxisymmetric plasma pressure distribution was analyzed under the assumption of magnetostatic equilibrium for finite values of the plasma parameter at the pressure maximum area. The distributions of isolines of the constant value of magnetic-field component B Z and the volume of magnetic flux tube in the equatorial plane were obtained. At a finite plasma pressure, local minima and maxima of the magnetic field are formed. The formation of these local maxima and minima leads to the formation of contours (not surrounding the Earth) B min = const, where B min is the minimum magnetic field on the magnetic field line. This changes the direction of the gradient of the volume of the magnetic flux tube. The configuration of appearing field-aligned currents was determined. The results obtained are discussed in terms of their use in explaining a number of effects observed in the Earth's magnetosphere.
7. Recent improvements in superconducting cable for accelerator dipole magnets
SciTech Connect
Scanlan, R.M.; Royet, J.M.
1991-05-01
The superconducting magnets required for the SSC have provided a focus and substantial challenge for the development of superconducting wire and cable. The number of strands in the cables have been increased from 23 for the Tevatron to 30 for the SSC inner layer cable and 36 for the SSC outer cable. Critical current degradation associated with cabling has been reduced from 15% for the Tevatron to less than 5%. R D which has led to these improvements will be described and the opportunities for further advances will be discussed. 11 refs., 2 figs., 1 tab.
8. Investigation of the magnetic dipole field at the atomic scale in quasi-one-dimensional paramagnetic conductor Li0.9Mo6O17.
PubMed
Wu, Guoqing; Ye, Xiao-shan; Zeng, Xianghua; Wu, Bing; Clark, W G
2016-01-13
We report magnetic dipole field investigation at the atomic scale in a single crystal of quasi-one-dimensional (Q1D) paramagnetic conductor Li0.9Mo6O17, using a paramagnetic electron model and (7)Li-NMR spectroscopy measurements with an externally applied magnetic field B 0 = 9 T. We find that the magnetic dipole field component ([Formula: see text]) parallel to B 0 at the Li site from the Mo electrons has no lattice axial symmetry; it is small around the middle between the lattice a and c axes in the ac-plane with the minimum at the field orientation angle [Formula: see text], while the [Formula: see text] maximum is at [Formula: see text] when B 0 is applied perpendicular to b ([Formula: see text]), where [Formula: see text] represents the direction of [Formula: see text]. Further estimation indicates that [Formula: see text] has a maximum value of 0.35 G at B 0 = 9 T. By minimizing the potential magnetic contributions to the NMR spectra satellites with the NMR spectroscopy measurements at the direction where the value of the magnetic dipole field component [Formula: see text] is ∼0, the behavior of the electron charge statics is exhibited. This work demonstrates that the magnetic dipole field of the Mo electrons is the dominant source of the local magnetic fields at the Li site, and suggests that the unknown metal-'insulator' crossover at low temperatures is not a charge effect. The work also reveals valuable local electric and magnetic field information for further NMR investigation as recently suggested (2012 Phys. Rev. B 85 235128) regarding the unusual properties of the material. PMID:26571041
9. Investigation of the magnetic dipole field at the atomic scale in quasi-one-dimensional paramagnetic conductor Li0.9Mo6O17
NASA Astrophysics Data System (ADS)
Wu, Guoqing; Ye, Xiao-shan; Zeng, Xianghua; Wu, Bing; Clark, W. G.
2016-01-01
We report magnetic dipole field investigation at the atomic scale in a single crystal of quasi-one-dimensional (Q1D) paramagnetic conductor Li0.9Mo6O17, using a paramagnetic electron model and 7Li-NMR spectroscopy measurements with an externally applied magnetic field B 0??=??9 T. We find that the magnetic dipole field component (B\\parallel\\text{dip} ) parallel to B 0 at the Li site from the Mo electrons has no lattice axial symmetry; it is small around the middle between the lattice a and c axes in the ac-plane with the minimum at the field orientation angle ? =+{{52.5}\\circ} , while the B\\parallel\\text{dip} maximum is at ? =+{{142.5}\\circ} when B 0 is applied perpendicular to b ({{B}0}\\bot b ), where ? ={{0}\\circ} represents the direction of {{B}0}\\parallel c . Further estimation indicates that B\\parallel\\text{dip} has a maximum value of 0.35 G at B 0??=??9 T. By minimizing the potential magnetic contributions to the NMR spectra satellites with the NMR spectroscopy measurements at the direction where the value of the magnetic dipole field component B\\parallel\\text{dip} is???0, the behavior of the electron charge statics is exhibited. This work demonstrates that the magnetic dipole field of the Mo electrons is the dominant source of the local magnetic fields at the Li site, and suggests that the unknown metal-insulator crossover at low temperatures is not a charge effect. The work also reveals valuable local electric and magnetic field information for further NMR investigation as recently suggested (2012 Phys. Rev. B 85 235128) regarding the unusual properties of the material.
10. Cavity QED Based on Collective Magnetic Dipole Coupling: Spin Ensembles as Hybrid Two-Level Systems
NASA Astrophysics Data System (ADS)
Imamoǧlu, Atac
2009-02-01
We analyze the magnetic dipole coupling of an ensemble of spins to a superconducting microwave stripline structure, incorporating a Josephson junction based transmon qubit. We show that this system is described by an embedded Jaynes-Cummings model: in the strong coupling regime, collective spin-wave excitations of the ensemble of spins pick up the nonlinearity of the cavity mode, such that the two lowest eigenstates of the coupled spin wave-microwave cavity-Josephson junction system define a hybrid two-level system. The proposal described here enables new avenues for nonlinear optics using optical photons coupled to spin ensembles via Raman transitions. The possibility of strong coupling cavity QED with magnetic dipole transitions also opens up the possibility of extending quantum information processing protocols to spins in silicon or graphene, without the need for single-spin confinement.
11. Dynamical map for combined function magnets with solenoid, dipole, and quadrupole fields
SciTech Connect
Venturini, Marco; Wolski, Andy
2004-06-30
The interaction regions of colliders invariably include strong solenoid fields. Where quadrupoles and dipoles are embedded in the solenoid, the beam dynamics in the combined fields can be complicated to model using the traditional approach of interleaving slices of the different fields. The complexity increases if the design trajectory is offset from the magnetic axis; this is the case, for example, in PEP-II. In this paper, we present maps for combined solenoid, dipole and quadrupole fields that provide a much simpler alternative to the traditional approach, and show that the deviation of the design trajectory from the magnetic axis can be handle in a straightforward manner. We illustrate the techniques presented by reference to the PEP-II interaction region.
12. Future Muon Dipole Moment Measurements
NASA Astrophysics Data System (ADS)
Roberts, B. Lee
2005-10-01
From the famous experiments of Stern and Gerlach to the present, measurements of magnetic dipole moments, and searches for electric dipole moments of "elementary" particles have played a major role in our understanding of sub-atomic physics. In this talk I discuss the progress on measurements and theory of the magnetic dipole moment of the muon. I also discuss a new proposal to search for a permanent electric dipole moment (EDM) of the muon and put it into the more general context of other EDM searches. These experiments, along with searches for the lepton flavor violating decays μ→eγ and μ+A→e+A, provide a path to the high-energy frontier through precision measurements.
13. The permanent electric dipole moment of thorium sulfide, ThS
SciTech Connect
Le, Anh; Steimle, Timothy C.; Heaven, Michael C.
2014-01-14
Numerous rotational lines of the (18.26)1-X{sup 1}Σ{sup +} band system of thorium sulfide, ThS, were recorded near 547.6 nm at a resolution of approximately 30 MHz. Measurements were made under field-free conditions, and in the presence of a static electric field. The field-free spectrum was analyzed to produce rotational and Λ-doubling parameters. The Stark shifts induced by the electric field were analyzed to determine permanent electric dipole moments, μ{sup -vector}{sub el}, of 4.58(10) D and 6.72(5) D for the X{sup 1}Σ{sup +} (v = 0) and (18.26)1 states, respectively. The results are compared with the predictions of previous and new electronic structure calculations for ThS, and the properties of isovalent ThO.
14. The permanent electric dipole moment of thorium sulfide, ThS.
PubMed
Le, Anh; Heaven, Michael C; Steimle, Timothy C
2014-01-14
Numerous rotational lines of the {18.26}1-X(1)Σ(+) band system of thorium sulfide, ThS, were recorded near 547.6 nm at a resolution of approximately 30 MHz. Measurements were made under field-free conditions, and in the presence of a static electric field. The field-free spectrum was analyzed to produce rotational and Λ-doubling parameters. The Stark shifts induced by the electric field were analyzed to determine permanent electric dipole moments, μ⃗el, of 4.58(10) D and 6.72(5) D for the X(1)Σ(+) (v = 0) and {18.26}1 states, respectively. The results are compared with the predictions of previous and new electronic structure calculations for ThS, and the properties of isovalent ThO. PMID:24437877
15. The permanent electric dipole moments of chromium and vanadium mononitride: CrN and VN
SciTech Connect
Steimle, T.C.; Robinson, J.S.; Goodridge, D.
1999-01-01
The P{sub e}(1), F{sup {double_prime}}=2.5 branch feature of the (0,0) Dthinsp{sup 3}{Pi}{sub 0e}{endash}Xthinsp{sup 3}{Delta}{sub 1} band system of {sup 51}VN was recorded as a function of an applied static electric field. The resultant Stark splitting and shifts were analyzed giving values of 3.07(7) D and 6.1(4) D for the Xthinsp{sup 3}{Delta}{sub 1} and Dthinsp{sup 3}{Pi}{sub 0e} states, respectively, for the magnitude of the permanent electric dipole moment, {vert_bar}{mu}{vert_bar}. Similarly, the R{sub ee}(0.5) branch feature of the (0,0) Athinsp{sup 4}{Pi}{sub 3/2}{endash}Xthinsp{sup 4}{Sigma}{sup {minus}} band system of {sup 52}CrN was recorded as a function of an applied static electric field and analyzed to produce {vert_bar}{mu}{vert_bar} values of 2.31(4) D and 5.42(2) D for the Xthinsp{sup 4}{Sigma}{sup {minus}} and Athinsp{sup 4}{Pi}{sub 3/2} states, respectively. In order to facilitate the dipole moment determinations for {sup 52}CrN it was necessary to record and analyze the field free spectrum of the (0,0) Athinsp{sup 4}{Pi}{sub 3/2}{endash}Xthinsp{sup 4}{Sigma}{sup {minus}} subband system. A comparison of the dipole moments for the first row monoxides and mononitrides is made and trends are discussed with reference to a molecular orbital correlation scheme. {copyright} {ital 1999 American Institute of Physics.}
16. Effect of Membrane Tension on the Electric Field and Dipole Potential of Lipid Bilayer Membrane
PubMed Central
Warshaviak, Dora Toledo; Muellner, Michael J.; Chachisvilis, Mirianas
2011-01-01
The dipole potential of lipid bilayer membrane controls the difference in permeability of the membrane to oppositely charged ions. We have combined molecular dynamics (MD) simulations and experimental studies to determine changes in electric field and electrostatic potential of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid bilayer in response to applied membrane tension. MD simulations based on CHARMM36 force field showed that electrostatic potential of DOPC bilayer decreases by ~45 mV in the physiologically relevant range of membrane tension values (0 to 15 dyn/cm). The electrostatic field exhibits a peak (~0.8×109 V/m) near the water/lipid interface which shifts by 0.9 Å towards the bilayer center at 15 dyn/cm. Maximum membrane tension of 15 dyn/cm caused 6.4% increase in area per lipid, 4.7% decrease in bilayer thickness and 1.4% increase in the volume of the bilayer. Dipole-potential sensitive fluorescent probes were used to detect membrane tension induced changes in DOPC vesicles exposed to osmotic stress. Experiments confirmed that dipole potential of DOPC bilayer decreases at higher membrane tensions. These results are suggestive of a potentially new mechanosensing mechanism by which mechanically induced structural changes in the lipid bilayer membrane could modulate the function of membrane proteins by altering electrostatic interactions and energetics of protein conformational states. PMID:21722624
17. Electro-Magnetic Dipole Properties of The Even-Even {sup 160}Gd Nucleus in The Spectroscopic Region
SciTech Connect
Ertugral, Filiz; Kuliev, Ali; Guliyev, Ekber
2008-11-11
In this study result of calculations using rotational, translational and Galilean invariant quasiparticle random-phase approximation is presented for the low lying dipole excitations in the even-even {sup 60}Gd nucleus. To make detail structure analysis for electric and magnetic dipole states, calculations carried out for both {delta}K = 1 and {delta}K = 0 branches. The analysis shows that almost all transitions with {delta}K = 1 are magnetic character in 2.4 divide 4 MeV energy interval. However, the calculations indicate the presence of a few prominent negative parity K{sup {pi}} = 1 states in the investigated energy interval, one of them with rather high E1 strength B(E1) = 7.1{center_dot}10{sup -3} e{sup 2} fm{sup 2} at energy 3.2 MeV. Calculated M1 dipole strength of the scissors mode K{sup {pi}} = 1{sup +} excitations clustered in two groups around 2.7 and 3.3 MeV. A similar situation arises for the experimentally obtained states two bumps around {omega}{sub i} = 2.7 MeV and {omega}{sub i} = 3.3 MeV. It has been shown that main part of spin-1 states, observed at energy 2.4 divide 4 MeV in {sup 160}Gd may be attributed to have M1 character and may be interpreted as main fragments of the scissors mode. However, it is apparent that the experimental data exceeds the calculation results for the summed B(M1) by a factor of 1.13 for M1 transitions.
18. Reduced Limit on the Permanent Electric Dipole Moment of Hg 199
NASA Astrophysics Data System (ADS)
Graner, B.; Chen, Y.; Lindahl, E. G.; Heckel, B. R.
2016-04-01
This Letter describes the results of the most recent measurement of the permanent electric dipole moment (EDM) of neutral Hg 199 atoms. Fused silica vapor cells containing enriched Hg 199 are arranged in a stack in a common magnetic field. Optical pumping is used to spin polarize the atoms orthogonal to the applied magnetic field, and the Faraday rotation of near-resonant light is observed to determine an electric-field-induced perturbation to the Larmor precession frequency. Our results for this frequency shift are consistent with zero; we find the corresponding Hg 199 EDM dHg=(-2.20 ±2.7 5stat±1.4 8syst)×10-30e cm . We use this result to place a new upper limit on the Hg 199 EDM |dHg|<7.4 ×10-30e cm (95% C.L.), improving our previous limit by a factor of 4. We also discuss the implications of this result for various C P -violating observables as they relate to theories of physics beyond the standard model.
19. Further evidence for the new collective magnetic dipole mode in heavy deformed nuclei
NASA Astrophysics Data System (ADS)
Bohle, D.; Küchler, G.; Richter, A.; Steffen, W.
1984-11-01
High-resolution inelastic electron scattering on 154Sm, 158Gd, 164Dy, 168Er and 174Yb provides further evidence on the recently discovered low-lying magnetic dipole mode. We present here spectra, form factors and estimates for transition strengths and use mainly the interacting boson model (IBA-2) for comparison. We also show first results on the fragmentation of the strength of the new mode in 156Gd.
20. Spin response of magnetic dipole transitions in 156Gd and 164Dy
NASA Astrophysics Data System (ADS)
Frekers, D.; Bohle, D.; Richter, A.; Abegg, R.; Azuma, R. E.; Celler, A.; Chan, C.; Drake, T. E.; Jackson, K. P.; King, J. D.; Miller, C. A.; Schubank, R.; Watson, J.; Yen, S.
1989-03-01
Intermediate energy proton scattering has been used to probe the spin part of the recently discovered low-lying isovector magnetic dipole transitions in the rotational rare earth nuclei 156Gd and 164Dy. A large spin response is found in 164Dy, whereas in 156Gd the results are consistent with the picture of a predominantly convective excitation. The results are discussed in the context of the IBA-2 model and recent RPA calculations.
1. Construction and results of the 50 mm short R D dipole magnets
SciTech Connect
Morgan, G.H.; Anerella, M.; Cottingham, J.; Ganetis, G.; Garber, M.; Ghosh, A.; Greene, A.; Gupta, R.; Herrera, J.; Kahn, S.; Kelly, E.; Morgillo, A.; Muratore, J.; Prodell, A.; Rehak, M.; Rohrer, E.P.; Sampson, W.; Shutt, R.; Thompson, P.; Wanderer, P.; Willen, E. ); Goodzeit, C.; Radusewicz, P. )
1991-01-01
The first at Brookhaven National Laboratory (BNL) of the large bore, 1.8 m SSC dipoles have been built and tested. The 2-D design of the coil, using the new, wider cables and the iron cross section are reviewed and the coil ends are described. Results from tests, including quench performance, magnetic field measurements and strain-gauge data are presented. 5 refs., 4 figs., 1 tab.
2. The identification of hot electron rings in spindle cusp using a magnetic dipole analyzer
SciTech Connect
Leal-Quiros, E.; Prelas, M.A. . Dept. of Nuclear Engineering)
1991-12-01
This paper reports on a magnetic dipole analyzer that has been built and used to measure fundamental parameters on the M4X, an experimental mirror machine with a spindle cusp and simple mirror modes of operation. A result using the M4X is the direct observation of the dimagnetic effect during the formation of hot electron rings in the spindle cusp configuration using electron cyclotron resonance heating.
3. Neutron and electron electric dipole moment in N=1 supergravity unification
SciTech Connect
Ibrahim, T.; Nath, P.
1998-01-01
An analysis of the neutron EDM and of the electron EDM in minimal N=1 supergravity unification with two CP-violating phases is given. For the neutron the analysis includes the complete one loop gluino, chargino, and neutralino exchange diagrams for the electric dipole and the chromoelectric dipole operators, and also the contribution of the purely gluonic dimension-six operator. It is shown that there exist significant regions in the six-dimensional parameter space of the model where cancellations between the gluino and the chargino exchanges reduce the electric and the chromoelectric contributions, and further cancellations among the electric, the chromoelectric, and the purely gluonic parts lead to a dramatic lowering of the neutron EDM sometimes below the electron EDM value. This phenomenon gives a new mechanism, i.e., that of internal cancellations, for the suppression of the neutron EDM in supersymmetric theories. The cancellation mechanism can significantly reduce the severe fine-tuning problem associated with CP-violating phases in SUSY and SUGRA unified models. {copyright} {ital 1997} {ital The American Physical Society}
4. Geometric-phase-induced false electric dipole moment signals for particles in traps
SciTech Connect
Pendlebury, J.M.; Harris, P.G.; Richardson, J.D.; Baskin, R.J.; Doyle, D.D.; May, D.J.R.; Smith, K.F.; Heil, W.; Sobolev, Yu.; Geltenbort, P.; Green, K.; Grinten, M.G.D. van der; Iaydjiev, P.S.; Ivanov, S.N.
2004-09-01
Theories are developed to evaluate Larmor frequency shifts, derived from geometric phases, in experiments to measure electric dipole moments (EDM's) of trapped, atoms, molecules, and neutrons. A part of these shifts is proportional to the applied electric field and can be interpreted falsely as an electric dipole moment. A comparison is made between our theoretical predictions for these shifts and some results from our recent experiments, which shows agreement to within the experimental errors of 15%. The comparison also demonstrates that some trapped particle EDM experiments have reached a sensitivity where stringent precautions are needed to minimize and control such false EDM's. Computer simulations of these processes are also described. They give good agreement with the analytical results and they extend the study by investigating the influence of varying surface reflection laws in the hard-walled traps considered. They also explore the possibility to suppress such false EDM's by introducing collisions with buffer gas particles. Some analytic results for frequency shifts proportional to the square of the E field are also given and there are results for the averaging of the B field in the absence of an E field.
5. Combined Electrical and Magnetic Resistivity Tomography: Theory and Inverse Modeling
SciTech Connect
Heath, Gail Lynn; Svoboda, John Mark; LaBrecque, Douglas; Sharpe, Roger; Casale, Dan
2003-09-01
Electrical Resistivity Tomography (ERT), which has seen increasingly wide use for environmental monitoring, uses the measurement of electrical potentials induced by a low-frequency electric current source. An alternative technique, magnetometric resistivity (MMR), measures the magnetic fields created by the same type of low-frequency electric current source used for ERT. Combining these two methods and thus the two types of data, provides an opportunity for producing improved subsurface images in a wider range of environments. This paper discusses the use of a fully three-dimensional inverse routine that combines magnetic and electric field measurements. The algorithm is based on a 3-D finite difference forward algorithm. The magnetic fields are modeled by applying the reciprocity theorem to model the electric fields induced by a coil of unit moment at a frequency of one radian per second. Using this method, allows for an adjoint formulation for calculating sensitivities of both magnetic and electric fields with respect to changes in the conductivities of individual cells within the finite-difference mesh. In initial model studies, combined MMR/ERT surveys were better able to resolve 3-D structures than ERT alone. The paper also considers design issues and choices of arrays for MMR surveys over a simple 3-D model. In this case, an integral-equation modeling algorithm is used to calculate the expected magnetic fields over a simple 3-D model. Several horizontal and buried vertical electric sources with surface magnetic receivers are employed. This work suggest that in-well horizontal arrays produce the strongest anomalous signals, while vertical dipoles provide the best sensitivity to target location.
6. On the nature of low-lying electric dipole excitations in light and heavy deformed nuclei
NASA Astrophysics Data System (ADS)
Guhr, T.; Hummel, K.-D.; Kilgus, G.; Bohle, D.; Richter, A.; De Jager, C. W.; De Vries, H.; De Witt Huberts, P. K. A.
1989-09-01
Form factors from high-resolution inelastic electron scattering on 48Ti, 164Dy, 232Th and 238U display the fact that the E1 transition to the lowest lying Jπ = 1 - states is excited by the same mode in light and heavy nuclei. A description of the form factor in terms of surface octupole vibrations of the nucleus around a quadrupole deformed shape is shown to work quite well up to its second maximum. The E1 strength found at the photon point is explained satisfactorily by taking into account the mixing with the electric giant dipole resonance.
7. Energies and Electric Dipole Transitions for Low-Lying Levels of Protactinium IV and Uranium V
NASA Astrophysics Data System (ADS)
Ürer, Güldem; Özdemir, Leyla
2012-02-01
We have reported a relativistic multiconfiguration Dirac-Fock (MCDF) study on low-lying level structures of protactinium IV (Z =91) and uranium V (Z =92) ions. Excitation energies and electric dipole (E1) transition parameters (wavelengths, oscillator strengths, and transition rates) for these low-lying levels have been given. We have also investigated the influence of the transverse Breit and quantum electrodynamic (QED) contributions besides correlation effects on the level structure. A comparison has been made with a few available data for these ions in the literature.
8. Search for the Neutron Electric Dipole Moment at the SNS at Oak Ridge
SciTech Connect
Kolarkar, Ameya
2010-02-10
The possible existence of a non-zero electric dipole moment (EDM) of the neutron is of fundamental interest for our understanding of the nature of electro-weak and strong interactions. The experimental search for this moment has the potential to reveal new sources of T and CP violation and to challenge calculations that propose extensions to the Standard Model. A new experiment being developed at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory seeks to lower the current EDM limit of the neutron by a factor of 50 to 100 over the present upper limit of 2.9x10{sup -26} e cm.
9. Atomic Spin Squeezing Towards Sub-Shot-Noise Measurement Of Permanent Electric Dipole Moment
SciTech Connect
Takano, T.; Fuyama, M.; Yamamoto, H.; Takahashi, Y.
2007-06-13
We have been studying laser-cooled and trapped atoms towards the detection of the permanent electric dipole moment (p-EDM). The existence of the p-EDM shows the CP-violation and its detection has significant implications for the test of the proposed elementary particle models. However, the current experimental accuracy has not yet reached the range of the predicted value of the standard model. Especially, a measurement error due to a shot noise is one of the important factors. To overcome the shot-noise limit, we are now trying to generate the atomic squeezed spin state.
10. Electric dipole moments as probes of new CP-odd physics
SciTech Connect
2009-12-17
We review the importance of precision probes for flavor-diagonal CP-violation, specifically searches for electric dipole moments of nucleons, atoms and molecules, in accessing new CP-odd physics at high scales. We summarize the effective field theory analysis of observable EDMs in terms of a general set of CP-odd operators at 1 GeV, and the ensuing model-independent new physics constraints, incorporating the recently improved limit on the Hg EDM. We also discuss the current status of these limits in the context of 1- and 2-loop contributions in supersymmetric models.
11. New concept for a neutron electric dipole moment search using a pulsed beam
NASA Astrophysics Data System (ADS)
Piegsa, Florian M.
2013-10-01
A concept to search for a neutron electric dipole moment (nEDM) is presented, which employs a pulsed neutron beam instead of the established use of storable ultracold neutrons (UCN). The technique takes advantage of the high peak flux and the time structure of a next-generation pulsed spallation source like the planned European Spallation Source. It is demonstrated that the sensitivity for a nEDM can be improved by several orders of magnitude compared to the best beam experiments performed in the 1970s and can compete with the sensitivity of UCN experiments.
12. Theory of global thermoremanent magnetization of planetary lithospheres in dipole fields of internal origin
NASA Technical Reports Server (NTRS)
Srnka, L. J.; Mendenhall, M. H.
1979-01-01
A model is presented for the global thermoremanent magnetization of spherical lithospheres which cool in the presence of central dipole fields. Reversals and intensity variations of the field are incorporated in this model, which is applicable to bodies whose interiors have remained above the Curie point throughout their evolution. The model demonstrates that even considering Runcorn's (1975) magnetostatics theorems for spherical shells, a nonzero magnetic permeability and a finite cooling rate in the lithosphere permit the acquisition of a sizable global remanent dipole moment, which would be detectable by external measurements after the magnetizing field has disappeared. Preliminary application of this model to Mercury, Venus, and Mars suggests that only the combination of a nonreversing ancient source field with a surface value near 1 Oe plus a sizable concentration (about 1% by volume) of ferromagnetic material in their crusts could produce remanent planetary dipole fields as large as those measured by spacecraft. On the other hand, if ancient reversing dynamos existed in these planets, it is unlikely that large planetary-scale fields like those observed at Mercury could be due to remanence in their crusts, irrespective of their composition.
13. Cryostat design for the Superconducting Super Collider 50mm aperture dipole magnet
SciTech Connect
Nicol, T.H. ); Tsavalas, Y.P. . Medical Systems)
1990-09-01
The cryostat of an SSC dipole magnet consists of all magnet components except the cold mass assembly. It serves to support the cold mass accurately and reliably within the vacuum vessel, provide all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations and must be manufacturable at low cost. The major components of the cryostat are the vacuum vessel, thermal shields, multilayer insulation (MLI) system, cryogenic piping, interconnections, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course their 25 year expected life. This paper describes the design of the current SSC collider dipole magnet cryostat and includes discussions on the thermal, structural, and dynamic considerations involved in the development of each of the major systems. 7 refs., 1 fig., 2 tabs.
14. Control of magnetic dipole terahertz radiation by cavity-based phase modulation.
PubMed
Li, J; Higuchi, T; Kanda, N; Konishi, K; Tikhodeev, S G; Kuwata-Gonokami, M
2011-11-01
Although it is well accepted that the ultrafast manipulation of spins or magnetization in solid promises potential applications in coherent terahertz (THz) radiation source, spintronics and quantum information processing, their performance is significantly limited by the weak coupling between radiation field and magnetic dipole oscillation. For such 'weak' magnetic system, we propose an effective and simple route based on the cavity-based phase modulation technique towards the efficient energy extraction, demonstrated via controlling the magnetic dipole THz radiation generated in the nonlinear Raman process from antiferromagnetic (AFM) NiO. An asymmetric coupled Fabry-Pérot (FP) cavity is constituted by simply placing a metallic planar mirror in the vicinity of a NiO slab. The energy-extraction (THz radiation) can be effectively manipulated by changing the NiO-mirror distance to modulate the phase relation between the magnetic wave and the induced magnetization in NiO. The distinct radiation control can be observed and the experiments are well explained by numerically analyzing the radiation dynamics that highlights the role of phase modulation during the radiation process. PMID:22109133
15. Design study of 15-Tesla RHQT Nb3Al block type dipole magnet
SciTech Connect
Yamada, R.; Ambrosio, G.; Barzi, E.; Kashikin, V.; Kikuchi, A.; Novitski, I.; Takeuchi, T.; Wake, M.; Zlobin, A.; /Fermilab /NIMC, Tsukuba /KEK, Tsukuba
2005-09-01
The design study of the block type 15-Tesla RHQT Nb{sub 3}Al dipole magnet, and its merits over Nb{sub 3}Sn magnets are presented. The copper stabilized RHQT Nb{sub 3}Al strand is now becoming commercially available for the application to the accelerator magnets. A 1 mm diameter RHQT Nb{sub 3}Al strand with filament size about 50 {mu}, non-copper Jc about 1000 A/mm{sup 2} at 15 Tesla at 4.2K, copper ratio of 50%, can now be produced over several hundred meters. The stress and strain characteristics of the Nb{sub 3}Al strand are superior to the Nb{sub 3}Sn strand. Another advantage is that it can tolerate a longitudinal strain up to 0.55%. The RHQT Nb{sub 3}Al Rutherford cable will have less chance of contamination of the stabilizer, compared to Nb{sub 3}Sn cable. These characteristics of the RHQT Nb{sub 3}Al will be beneficial for designing and producing 15-Tesla dipole magnets. An example 15-Tesla magnet cross section, utilizing the RHQT Nb{sub 3}Sn strand is presented. A systematic investigation on RHQT Nb{sub 3}Al strands, its Rutherford cables, and building a small racetrack magnet for cable testing are proposed.
16. Magnetic dipole excitations in nuclei: Elementary modes of nucleonic motion
SciTech Connect
Heyde, Kris; Neumann-Cosel, Peter von; Richter, Achim
2010-07-15
The nucleus is one of the most multifaceted many-body systems in the Universe. It exhibits a multitude of responses depending on the way one ''probes'' it. With increasing technical advancements of beams at the various accelerators and of detection systems the nucleus has, over and over again, surprised us by expressing always new ways of ''organized'' structures and layers of complexity. Nuclear magnetism is one of those fascinating faces of the atomic nucleus discussed in the present review. We shall not just limit ourselves to presenting the by now large data set that has been obtained in the past two decades using various probes, electromagnetic and hadronic alike and that presents ample evidence for a low-lying orbital scissors mode around 3 MeV, albeit fragmented over an energy interval of the order of 1.5 MeV, and higher-lying spin-flip strength in the energy region 5-9 MeV in deformed nuclei nor to the presently discovered evidence for low-lying proton-neutron isovector quadrupole excitations in spherical nuclei. To the contrary, the experimental evidence is put in the perspectives of understanding the atomic nucleus and its various structures of well-organized modes of motion and thus enlarges the discussion to more general fermion and bosonic many-body systems.
17. Mechanical analysis of the Nb3Sn dipole magnet HD1
SciTech Connect
Ferracin, Paolo; Bartlett, Scott E.; Caspi, Shlomo; Dietderich,Daniel R.; Gourlay, Steve A.; Hannaford, Carles R.; Hafalia, Aurelio R.; Lietzke, Alan F.; Mattafirri, Sara; Sabbi, Gianluca
2005-04-14
The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has recently fabricated and tested HD1, a Nb{sub 3}Sn dipole magnet. The magnet reached a 16 T field, and exhibited training quenches in the end regions and in the straight section. After the test, HD1 was disassembled and inspected, and a detailed 3D finite element mechanical analysis was done to investigate for possible quench triggers. The study led to minor modifications to mechanical structure and assembly procedure, which were verified in a second test (HD1b). This paper presents the results of the mechanical analysis, including strain gauge measurements and coil visual inspection. The adjustments implemented in the magnet structure are reported and their effect on magnet training discussed.
18. Mechanical Analysis of the Nb3Sn Dipole Magnet HD1
SciTech Connect
Ferracin, Paolo; Bartlett, Scott E.; Caspi, Shlomo; Dietderich, Daniel R.; Gourlay, Steve A.; Hannaford, Charles R.; Hafalia, Aurelio R.; Lietzke, Alan F.; Mattafirri, Sara; Sabbi, Gianluca
2005-06-01
The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has recently fabricated and tested HD1, a Nb3Sn dipole magnet. The magnet reached a 16 T field, and exhibited training quenches in the end regions and in the straight section. After the test, HD1 was disassembled and inspected, and a detailed 3D finite element mechanical analysis was done to investigate for possible quench triggers. The study led to minor modifications to mechanical structure and assembly procedure, which were verified in a second test (HD1b). This paper presents the results of the mechanical analysis, including strain gauge measurements and coil visual inspection. The adjustments implemented in the magnet structure are reported and their effect on magnet training discussed.
19. Thermodynamic Properties of the Superconducting Dipole Magnet of the SIS100 Synchrotron
NASA Astrophysics Data System (ADS)
Bleile, A.; Fischer, E.; Freisleben, W.; Mierau, A.; Schnizer, P.; Szwangruber, P.
The Heavy Ion Synchrotron SIS100 is the core facility of the international FAIR project at GSI in Darmstadt. The magnet system of the synchrotron will operate with a high cycle frequency up to 1 Hz. The magnet coils are made of a hollow NbTi composite cable cooled by forced flow of two phase helium. The dynamic heat losses in the magnets caused by fast ramping provide the major part of the heat load to the cryogenic system of SIS100. Recently the first series dipole magnet was produced and is being intensively tested at the cryogenic magnet test facility at GSI. We present the status of these tests together with the obtained opera- tion characteristics like a cool down and training behaviour, dynamic heat release and mass flow rates.
20. The design and manufacture of the Fermilab Main Injector Dipole Magnet
SciTech Connect
Brown, B.C.; Chester, N.S.; Harding, D.J.; Martin, P.S.
1992-03-01
Fermilabs new Main Injector Ring (MIR) will replace the currently operating Main Ring to provide 150 GeV Proton and Antiproton beams for Tevetron injection, and rapid cycling, high intensity, 120 GeV Proton beams for Antiproton production. To produce and maintain the required high beam quality, high intensity, and high repetition rate, conventional dipole magnets with laminated iron core and water cooled copper conductor were chosen as the bending magnet. A new magnet design having low inductance, large copper cross section, and field uniformity sufficient for high intensity injection and efficient slow resonant extraction, is required to obtain the needed geometric aperture, dynamic aperture, and operational reliability. The current Main Injector Ring lattice design requires the use of 344 of these magnets. 216 of these magnets are to be 6 m long, and 128 are to be 4 m long.
1. The design and manufacture of the Fermilab Main Injector Dipole Magnet
SciTech Connect
Brown, B.C.; Chester, N.S.; Harding, D.J.; Martin, P.S.
1992-03-01
Fermilab's new Main Injector Ring (MIR) will replace the currently operating Main Ring to provide 150 GeV Proton and Antiproton beams for Tevetron injection, and rapid cycling, high intensity, 120 GeV Proton beams for Antiproton production. To produce and maintain the required high beam quality, high intensity, and high repetition rate, conventional dipole magnets with laminated iron core and water cooled copper conductor were chosen as the bending magnet. A new magnet design having low inductance, large copper cross section, and field uniformity sufficient for high intensity injection and efficient slow resonant extraction, is required to obtain the needed geometric aperture, dynamic aperture, and operational reliability. The current Main Injector Ring lattice design requires the use of 344 of these magnets. 216 of these magnets are to be 6 m long, and 128 are to be 4 m long.
2. SQUIDs as detectors in a new experiment to measure the neutron electric dipole moment
SciTech Connect
Espy, M.A.; Cooper, M.; Lamoreaux, S.; Kraus, R.H. Jr.; Matlachov, A.; Ruminer, P.
1998-12-31
A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4{times}10{sup {minus}28} ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large ({approximately}100 cm{sup 2}) pick-up coils to measure the precision frequency of the spin-polarized {sup 3}He atoms that act as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the {sup 3}He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of {approximately}2{times}10{sup {minus}16} Tm{sup 2} (0.1 {Phi}{sub 0}) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of d{Phi}{sub SQ} = 2{times}10{sup {minus}6}{Phi}{sub 0}/{radical}Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application the authors designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and they developed a two-SQUID readout system that will reduce SQUID noise in the experiment. They present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. The authors also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique.
3. SQUIDs as Detectors in a New Experiment to Measure the Neutron Electric Dipole Moment
SciTech Connect
Espy, M.A.; Cooper, M.; Lamoreaux, S.; Kraus, R.H., Jr.; Matlachov, A.; Ruminer, P.
1998-09-13
A new experiment has been proposed at Los Alamos National Laboratory to measure the neutron electric dipole moment (EDM) to 4x10{sup {minus}28} ecm, a factor of 250 times better than the current experimental limit. Such a measure of the neutron EDM would challenge the theories of supersymmetry and time reversal violation as the origin of the observed cosmological asymmetry in the ratio of baryons to antibaryons. One possible design for this new experiment includes the use of LTC SQUIDs coupled to large ({approximately}100 cm{sup 2}) pick-up coils to measure the precession frequency of the spin-polarized {sup 3}He atoms that act as polarizer, spin analyzer, detector, and magnetometer for the ultra-cold neutrons used in the experiment. The method of directly measuring the {sup 3}He precession signal eliminates the need for very uniform magnetic fields (a major source of systematic error in these types of experiments). It is estimated that a flux of {approximately}2x10{sup {minus}16} Tm{sup 2} (0.1 F{sub 0}) will be coupled into the pick-up coils. To achieve the required signal-to-noise ratio one must have a flux resolution of d F{sub SQ}=2x10{sup {minus}6} F{sub 0}/{radical}Hz at 10 Hz. While this is close to the sensitivity available in commercial devices, the effects of coupling to such a large pick-up coil and flux noise from other sources in the experiment still need to be understood. To determine the feasibility of using SQUIDs in such an application we designed and built a superconducting test cell, which simulates major features of the proposed EDM experiment, and we developed a two-SQUID readout system that will reduce SQUID noise in the experiment. We present an overview of the EDM experiment with SQUIDs, estimations of required SQUID parameters and experimental considerations. We also present the measured performance of a single magnetometer in the test cell as well as the performance of the two SQUID readout technique
4. The Magnetic Dipole as an Attractive Fusion Reactor
NASA Astrophysics Data System (ADS)
Dawson, John M.
1997-11-01
Stability for low β plasma confined by closed B field lines is PV^γ = C_0, P = pressure, V = flux tube volume, γ is c_p/cv = 5/3. Kesner(J. Kesner, Innovative Confinement Concepts Workshop, Mar. 3-6, 1997) proposed a levitated current ring with the plasma stabilized by this condition as an alternate fusion reactor. Such a reactor has many attractive features; at radii large compared to the ring radius, V goes like r^4; the stability condition is Pr^20/3 = C_1. If nr^4 = C_2, then interchanges keep the density constant. The temperature can drop according to Tr^8/3 = C_3. If the chamber is ten times the ring radius, the density can drop from 10^14 near the ring to 10^10 at the edge and the temperature can drop from 50 keV near the ring to 100 eV at the edge. This plasma should present no problems for a divertor. Reacting plasma near the ring will heat it, upsetting the stability relation and cause convection to carry burnt plasma out; it will cool as it expands. At the same time the convection will bring in fresh fuel from the outside which will be compressed and heated to ignition. A super conducting ring design that can float in reacting D-He^3 for 16 hours exists(J.M. Dawson, FUSION, edited by Edward Teller, Vol. 1, Magnetic Confinement, Part, Ch. 16, Academic Press, 1981).
5. Zeeman interaction in ThO H3Δ1 for the electron electric-dipole-moment search
NASA Astrophysics Data System (ADS)
Petrov, A. N.; Skripnikov, L. V.; Titov, A. V.; Hutzler, N. R.; Hess, P. W.; O'Leary, B. R.; Spaun, B.; DeMille, D.; Gabrielse, G.; Doyle, J. M.
2014-06-01
The current limit on the electron's electric dipole moment, |de|<8.7×10-29 ecm (90% confidence), was set using the molecule thorium monoxide (ThO) in the J =1 rotational level of its H3Δ1 electronic state [J. Baron et al., Science 343, 269 (2014), 10.1126/science.1248213]. This state in ThO is very robust against systematic errors related to magnetic fields or geometric phases, due in part to its Ω-doublet structure. These systematics can be further suppressed by operating the experiment under conditions where the g-factor difference between the Ω doublets is minimized. We consider the g factors of the ThO H3Δ1 state both experimentally and theoretically, including dependence on Ω doublets, the rotational level, and the external electric field. The calculated and measured values are in good agreement. We find that the g-factor difference between Ω doublets is smaller in J =2 than in J =1 and reaches zero at an experimentally accessible electric field. This means that the H ,J=2 state should be even more robust against a number of systematic errors compared to H ,J=1.
6. Measurements of the persistent current decay and snapback effect in Tevatron dipole magnets
SciTech Connect
Velev, G.V.; Bauer, P.; DiMarco, J.; Hanft, R.; Lamm, M.; Schlabach, P.; Sylvester, C.; Tartaglia, M.; Tompkins, J.C.; /Fermilab
2006-08-01
A systematic study of the persistent current decay and snapback effect in the fields of Tevatron accelerator dipoles was performed at the Fermilab Magnet Test Facility (MTF). The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and magnet operational history. The study has mostly focused on the dynamic behavior of the normal sextupole component. In addition, the paper presents the persistent current effects observed in the other allowed field harmonics as well. The results provide new information about the previously observed ''excess'' decay during the first several seconds of the sextupole decay during injection and the correlation between the snapback amplitude and its duration.
7. A. C. losses in the SSC high energy booster dipole magnets
SciTech Connect
Jayakumar, R.; Kovachev, V.; Snitchler, G.; Orrell, D.
1991-06-01
The baseline design for the SSC High Energy Booster (HEB) has dipole bending magnets with a 50 mm aperture. An analysis of the cryogenic heat load due to A.C. losses generated in the HEB ramp cycle are reported for this magnet. Included in this analysis are losses from superconductor hysteresis, yoke hysteresis, strand eddy currents, and cable eddy currents. The A.C. loss impact of 2.5 {mu}m vs. 6 {mu}m filament conductor is presented. A 60 mm aperture design is also investigated. 8 refs., 3 tabs.
8. A 50 Hz dipole magnet for the TRIUMF KAON Factory booster ring
SciTech Connect
Otter, A.J. )
1992-01-01
The 3 GeV Booster synchrotron for TRIUMF's KAON Factory will need 24 dipole magnets each 3.0 m long operating with a resonant power system designed to give a 50 Hz ac field superimposed onto a dc field. The maximum and minimum field levels are 1.118 and 0.295 T respectively. In this paper the magnet design is presented and compared with measured results from a prototype which was constructed to evaluate fabrication procedures and to verify the ac loss calculations. The experiences gained from this fabrication are described.
9. Electric dipole moment and spin supercurrent in superfluid [sup 3]He
SciTech Connect
Mineev, V.P.; Volovik, G.E. Helsinki Univ. of Technology, Espoo )
1992-12-01
The SU(2) gauge invariant theory of the relativistic interaction of the electrically neutral superfluid [sup 3]He with electric and magnetic fields is formulated. The spin supercurrent response on the electric field is calculated for this interaction. The comparison with the nonrelativistic flexoelectric effect, arising due to the distortion of the atomic shell by the gradients of the superfluid order parameter, is made. 5 refs.
10. Sign Changes in the Electric Dipole Moment of Excited States in Rubidium-Alkaline Earth Diatomic Molecules
NASA Astrophysics Data System (ADS)
Pototschnig, Johann V.; Lackner, Florian; Hauser, Andreas W.; Ernst, Wolfgang E.
2015-06-01
In a recent series of combined experimental and theoretical studies we investigated the ground state and several excited states of the Rb-alkaline earth molecules RbSr and RbCa. The group of alkali-alkaline earth (AK-AKE) molecules has drawn attention for applications in ultracold molecular physics and the measurement of fundamental constants due to their large permanent electric and magnetic dipole moments in the ground state. These properties should allow for an easy manipulation of the molecules and simulations of spin models in optical lattices. In our studies we found that the permanent electric dipole moment points in different directions for certain electronically excited states, and changes the sign in some cases as a function of bond length. We summarize our results, give possible causes for the measured trends in terms of molecular orbital theory and extrapolate the tendencies to other combinations of AK and AKE - elements. F. Lackner, G. Krois, T. Buchsteiner, J. V. Pototschnig, and W. E. Ernst, Phys. Rev. Lett., 2014, 113, 153001; G. Krois, F. Lackner, J. V. Pototschnig, T. Buchsteiner, and W. E. Ernst, Phys. Chem. Chem. Phys., 2014, 16, 22373; J. V. Pototschnig, G. Krois, F. Lackner, and W. E. Ernst, J. Chem. Phys., 2014, 141, 234309 J. V. Pototschnig, G. Krois, F. Lackner, and W. E. Ernst, J. Mol. Spectrosc., in Press (2015), doi:10.1016/j.jms.2015.01.006 M. Kajita, G. Gopakumar, M. Abe, and M. Hada, J. Mol. Spectrosc., 2014, 300, 99-107 A. Micheli, G. K. Brennen, and P. Zoller, Nature Physics, 2006, 2, 341-347
11. Electric/magnetic field sensor
DOEpatents
Schill, Jr., Robert A.; Popek, Marc [Las Vegas, NV
2009-01-27
A UNLV novel electric/magnetic dot sensor includes a loop of conductor having two ends to the loop, a first end and a second end; the first end of the conductor seamlessly secured to a first conductor within a first sheath; the second end of the conductor seamlessly secured to a second conductor within a second sheath; and the first sheath and the second sheath positioned adjacent each other. The UNLV novel sensor can be made by removing outer layers in a segment of coaxial cable, leaving a continuous link of essentially uncovered conductor between two coaxial cable legs.
12. Modeling the internal magnetic field of Mercury using the Time Dependent Equivalent Source Dipole method
NASA Astrophysics Data System (ADS)
Oliveira, J. S.; Langlais, B.; Amit, H.; Pais, M. A.
2014-04-01
We model the internal magnetic field of Mercury as measured by the MESSENGER probe during its first year. We introduce a new modeling technique, the Time-Dependent Equivalent Source Dipole approach (TD-ESD). At a given location, the measured magnetic field is assumed to result from the sum of the contributions of individual dipoles located deep inside Mercury's interior which may vary with time to reflect the temporal variation of the Hermean magnetic field. We report first models computed with the TDESD method using only Mercury's sideral days separately. We discuss the time-evolution of the modeled field and compare it to the time-evolution of the residuals. There is a strong correlation between these two quantities, which confirms that external magnetic fields are somehow affecting the modeled, supposedly internal, field. We also compute a mean model using a complete solar day and find that most of the external fields are reduced. The mean magnetic equator at 200 km altitude is found at 10°N latitude on average, corresponding to a g02/g01 ratio of 0.28.
13. Time Dependent Equivalent Source Dipole - a new method to model the internal magnetic field of Mercury
NASA Astrophysics Data System (ADS)
Oliveira, J. S.; Langlais, B.; Amit, H.; Pais, M. A.
2012-12-01
The MErcury Surface, Space ENvironment, Geochemistry, and Ranging (MESSENGER) mission has been in orbit around Mercury since March 2011, providing a partial coverage of the Hermean magnetic field. Depending on the local time, MESSENGER may be inside the magnetosphere between 60°S and to 86°N latitude. There is however a strong signature of the external magnetic field, and only the lowest altitude measurements over the northern hemisphere (below ~1500 km) can be used to robustly characterize the internal magnetic field. Standard and global methods, such as the Spherical Harmonics analysis, are therefore not the most appropriate ones because of the very partial data coverage. Here we present a new method based on the Equivalent Source Dipole (ESD) approach. This method can be used either as a global or local one and is usually applied to downward or upward continue at constant altitude magnetic fields of crustal origin, i.e. static magnetic fields. We expand the method into a Time Dependent Equivalent Source Dipole (TD-ESD). This new method results from placing uniformly distributed dipolar sources at the surface of a spherical shell located deep into Mercury's interior. These sources are set to represent the internal magnetic field, and as a new feature, their parameters may vary with time. We are then able to model not only the three components of the Hermean magnetic field, but also its temporal variation. We test this approach using synthetic data predicted at spacecraft location. The internal magnetic field and its secular variation can be modeled and described from the pole down to 40°N latitude or so without edge effects. We next apply the TD-ESD method to MESSENGER's measurements. We will present the first constant altitude maps of the Hermean magnetic field that we derive, and discuss of the importance of the external fields.
14. Operator evolution for ab initio electric dipole transitions of 4He
DOE PAGESBeta
Schuster, Micah D.; Quaglioni, Sofia; Johnson, Calvin W.; Jurgenson, Eric D.; Navartil, Petr
2015-07-24
A goal of nuclear theory is to make quantitative predictions of low-energy nuclear observables starting from accurate microscopic internucleon forces. A major element of such an effort is applying unitary transformations to soften the nuclear Hamiltonian and hence accelerate the convergence of ab initio calculations as a function of the model space size. The consistent simultaneous transformation of external operators, however, has been overlooked in applications of the theory, particularly for nonscalar transitions. We study the evolution of the electric dipole operator in the framework of the similarity renormalization group method and apply the renormalized matrix elements to the calculationmore » of the 4He total photoabsorption cross section and electric dipole polarizability. All observables are calculated within the ab initio no-core shell model. Furthermore, we find that, although seemingly small, the effects of evolved operators on the photoabsorption cross section are comparable in magnitude to the correction produced by including the chiral three-nucleon force and cannot be neglected.« less
15. Contribution of relativistic quantum chemistry to electron's electric dipole moment for CP violation
NASA Astrophysics Data System (ADS)
Abe, M.; Gopakumar, G.; Das, B. P.; Tatewaki, H.; Mukherjee, D.; Hada, M.
2015-12-01
The search for the electric dipole moment of the electron (eEDM) is important because it is a probe of Charge Conjugation-Parity (CP) violation. It can also shed light on new physics beyond the standard model. It is not possible to measure the eEDM directly. However, the interaction energy involving the effective electric field (Eeff) acting on an electron in a molecule and the eEDM can be measured. This quantity can be combined with Eeff, which is calculated by relativistic molecular orbital theory to determine eEDM. Previous calculations of Eeff were not sufficiently accurate in the treatment of relativistic or electron correlation effects. We therefore developed a new method to calculate Eeff based on a four-component relativistic coupled-cluster theory. We demonstrated our method for YbF molecule, one of the promising candidates for the eEDM search. Using very large basis set and without freezing any core orbitals, we obtain a value of 23.1 GV/cm for Eeff in YbF with an estimated error of less than 10%. The error is assessed by comparison of our calculations and experiments for two properties relevant for Eeff, permanent dipole moment and hyperfine coupling constant. Our method paves the way to calculate properties of various kinds of molecules which can be described by a single-reference wave function.
16. Electromagnetic induction by a finite electric dipole source over a 2-D earth
SciTech Connect
Unsworth, M.J. ); Travis, B.J. ); Chave, A.D. )
1993-02-01
A numerical solution for the frequency domain electromagnetic response of a two-dimensional (2-D) conductivity structure to excitation by a three-dimensional (3-D) current source has been developed. The fields are Fourier transformed in the invariant conductivity direction and then expressed in a variational form. At each of a set of discrete spatial wavenumbers a finite-element method is used to obtain a solution for the secondary electromagnetic fields. The finite element uses exponential elements to efficiently model the fields in the far-field. In combination with an iterative solution for the along-strike electromagnetic fields, this produces a considerable reduction in computation costs. The numerical solutions for a horizontal electric dipole are computed and shown to agree with closed form expressions and to converge with respect to the parameterization. Finally some simple examples of the electromagnetic fields produced by horizontal electric dipole sources at both the sea floor and air-earth interface are presented to illustrate the usefulness of the code.
17. SGR 0418+5729: A SMALL INCLINATION ANGLE RESULTING IN A NOT SO LOW DIPOLE MAGNETIC FIELD?
SciTech Connect
Tong, H.; Xu, R. X.
2012-09-20
The spin-down behaviors of SGR 0418+5729 are investigated. The pulsar spin-down model of Contopoulos and Spitkovsky is applied to SGR 0418+5729. It is shown that SGR 0418+5729 lies below the pulsar death line and its rotation-powered magnetospheric activities may therefore have stopped. The compact star is now spun down by the magnetic dipole moment perpendicular to its rotation axis. Our calculations show that under these assumptions there is the possibility of SGR 0418+5729 having a strong dipole magnetic field, if there is a small magnetic inclination angle. Its dipole magnetic field may be much higher than the characteristic magnetic field. Therefore, SGR 0418+5729 may be a normal magnetar instead of a low magnetic field magnetar.
18. Electrically charged matter rotating around magnetized black holes
NASA Astrophysics Data System (ADS)
Kovar, Jiri; Slany, Petr; Stuchlik, Zdenek; Karas, Vladimir
2015-08-01
We present results of our study of charged-fluid toroidal structures surrounding a non-rotating black hole surrounded by a dipole and large-scale, asymptotically uniform magnetic fields. In continuation of our former study of electrically charged matter in approximation of zero conductivity, we demonstrate the existence of orbiting structures in the equatorial plane, levitating above it and those hovering near the symmetry axis. We constrain the range of black-hole, magnetic fields and matter parameters that allow stable configurations of the fluid structures and derive the geometrical shape of equi-pressure surfaces, characterizing the temperature and other astrophysical characteristic profiles. Our simplified analytical study suggests that these regions of stability may be relevant for trapping electrically charged particles and dust grains in some areas of the black hole magnetosphere, being thus important in some astrophysical situations.
19. The dipole corrector magnets for the RHIC fast global orbit feedback system
SciTech Connect
Thieberger, P.; Arnold, L.; Folz, C.; Hulsart, R.; Jain, A.; Karl, R.; Mahler, G.; Meng, W.; Mernick, K.; Michnoff, R.; Minty, M.; Montag, C.; Ptitsyn, V.; Ritter, J.; Smart, L.; Tuozzolo, J.; White, J.
2011-03-28
The recently completed RHIC fast global orbit feedback system uses 24 small 'window-frame' horizontal dipole correctors. Space limitations dictated a very compact design. The magnetic design and modelling of these laminated yoke magnets is described as well as the mechanical implementation, coil winding, vacuum impregnation, etc. Test procedures to determine the field quality and frequency response are described. The results of these measurements are presented and discussed. A small fringe field from each magnet, overlapping the opposite RHIC ring, is compensated by a correction winding placed on the opposite ring's magnet and connected in series with the main winding of the first one. Results from measurements of this compensation scheme are shown and discussed.
20. Performance analysis of HD1: a 16 Tesla Nb3Sn dipole Magnet
SciTech Connect
Mattafirri, S.; Bartlett, S.E.; Bish, P.A.; Caspi, S.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hannaford, C.R.; Hafalia, A.R.; Lau, W.G.; Lietzke, A.F.; McInturff, A.D.; Nyman, M.; Sabbi, G.L.; Scanlan, R.M.
2005-06-01
The Superconducting Magnet Group at Lawrence Berkeley National Laboratory (LBNL) has been developing technology for high field accelerator magnets from brittle conductors. HD1 is a single bore block dipole magnet using two, double-layer Nb{sub 3}Sn flat racetrack coils. The magnet was tested in October 2003 and reached a bore peak field of 16 T (94.5% of short sample). The average quench current plateau appeared to be limited by 'stick slip' conductor motions. Diagnostics recorded quench origins and preload distributions. Cumulative deformation of the mechanical structure has been observed. Quench velocity in different field regions has been measured and compared with model predictions. The results obtained during the HD1 test are presented and discussed.
1. Thermal equilibrium of non-neutral plasma in dipole magnetic field
NASA Astrophysics Data System (ADS)
Sato, N.; Kasaoka, N.; Yoshida, Z.
2015-04-01
Self-organization of a long-lived structure is one of the remarkable characteristics of macroscopic systems governed by long-range interactions. In a homogeneous magnetic field, a non-neutral plasma creates a "thermal equilibrium," which is a Boltzmann distribution on a rigidly rotating frame. Here, we study how a non-neutral plasma self-organizes in inhomogeneous magnetic field; as a typical system, we consider a dipole magnetic field. In this generalized setting, the plasma exhibits its fundamental mechanism that determines the relaxed state. The scale hierarchy of adiabatic invariants is the determinant; the Boltzmann distribution under the topological constraint by the robust adiabatic invariants (hence, the homogeneous distribution with respect to the fragile invariant) is the relevant relaxed state, which turns out to be a rigidly rotating clump of particles (just same as in a homogeneous magnetic field), while the density is no longer homogeneous.
2. Axial variations in the magnetic field of superconducting dipoles and quadrupoles
SciTech Connect
Ghosh, A.K.; Robins, K.E.; Sampson, W.B.
1993-09-01
A periodic variation in the magnetic field along the axis has been observed in both quadrupole and dipole magnets made from superconducting cable. This oscillation is present in all components of the field and has a wavelength equal to the transposition length of the cable. In general the amplitude of these variations increases with magnet current and is not reversible. The residual field patten at zero current depends on the energizing cycle and increases with time spent at high field. The decay of the oscillations has a complex time dependence which contains some extremely long time constants. Unbalanced currents in the individual strands of the cable appear to cause these effects and the field variations can only be completely erased by raising the magnet above its critical temperature.
3. HD1: Design and Fabrication of a 16 Tesla Nb3Sn DipoleMagnet
SciTech Connect
Hafalia, A.R.; Bartlett, S.E.; Capsi, S.; Chiesa, L.; Dietderich,D.R.; Ferracin, P.; Goli, M.; Gourlay, S.A.; Hannaford, C.R.; Highley,H.; Lietzke, A.F.; Liggins, N.; Mattafirri, S.; McInturff, A.D.; Nyman,M.; Sabbi, G.L.; Scanlan, R.M.; Swanson, J.
2003-11-10
The Lawrence Berkeley National Laboratory (LBNL) Superconducting Magnet Group has completed the design, fabrication and test of HD1, a 16 T block-coil dipole magnet. State of the art Nb{sub 3}Sn conductor was wound in double-layer racetrack coils and supported by an iron yoke and a tensioned aluminum shell. In order to prevent conductor movement under magnetic forces up to the design field, a coil pre-stress of 150 MPa was required. To achieve this level without damaging the brittle conductor, the target stress was generated during cool-down to 4.2 K by exploiting the thermal contraction differentials between yoke and shell. Accurate control of the shell tension during assembly was obtained using pressurized bladders and interference load keys. An integrated 3D CAD model was used to optimize magnetic and mechanical design and analysis.
4. HD1: Design and Fabrication of a 16 Tesla Nb3Sn Dipole Magnet
SciTech Connect
Hafalia, A.R.; Barlett, S.E.; Caspi, S.; Chiesa, L.; Dietderich, D.R.; Ferracin, P.; Goli, M.; Gourlay, S.A.; Hannaford, C.R.; Higley, H.; Lietzke, A.F.; Liggins, N.; Mattafirri, S.; McInturff, A.D.; Myman, M.; Sabbi, G.L.; Scanlan, R.M.; Swanson, J.
2003-10-01
The Lawrence Berkeley National Laboratory (LBNL) Supcrconducting Magnet Group has completed the design, fabrication and tcst of HD1, a 16 T block-coil dipole magnet. State of the art Nb{sub 3}Sn conductor was wound in double-layer racetrack coils and supported by an iron yoke and a tensioned aluminum shell. In order to prevent conductor movement under magnetic forces up to the design field, a coil prestress of 150 MPa was required. To achieve this level without damaging the brittle conductor, the target stress was generated during cool-down to 4.2 K by exploiting the thermal contraction differentials between yoke and shell. Accurate control of the shell tension during assembly was obtained using pressurized bladders and interference load keys. An integrated 3D CAD model was used to optimize magnetic and mechanical design and analysis.
5. Thermal equilibrium of non-neutral plasma in dipole magnetic field
SciTech Connect
Sato, N.; Kasaoka, N.; Yoshida, Z.
2015-04-15
Self-organization of a long-lived structure is one of the remarkable characteristics of macroscopic systems governed by long-range interactions. In a homogeneous magnetic field, a non-neutral plasma creates a “thermal equilibrium,” which is a Boltzmann distribution on a rigidly rotating frame. Here, we study how a non-neutral plasma self-organizes in inhomogeneous magnetic field; as a typical system, we consider a dipole magnetic field. In this generalized setting, the plasma exhibits its fundamental mechanism that determines the relaxed state. The scale hierarchy of adiabatic invariants is the determinant; the Boltzmann distribution under the topological constraint by the robust adiabatic invariants (hence, the homogeneous distribution with respect to the fragile invariant) is the relevant relaxed state, which turns out to be a rigidly rotating clump of particles (just same as in a homogeneous magnetic field), while the density is no longer homogeneous.
6. Applicability of the single equivalent point dipole model to represent a spatially distributed bio-electrical source
NASA Technical Reports Server (NTRS)
Armoundas, A. A.; Feldman, A. B.; Sherman, D. A.; Cohen, R. J.
2001-01-01
Although the single equivalent point dipole model has been used to represent well-localised bio-electrical sources, in realistic situations the source is distributed. Consequently, position estimates of point dipoles determined by inverse algorithms suffer from systematic error due to the non-exact applicability of the inverse model. In realistic situations, this systematic error cannot be avoided, a limitation that is independent of the complexity of the torso model used. This study quantitatively investigates the intrinsic limitations in the assignment of a location to the equivalent dipole due to distributed electrical source. To simulate arrhythmic activity in the heart, a model of a wave of depolarisation spreading from a focal source over the surface of a spherical shell is used. The activity is represented by a sequence of concentric belt sources (obtained by slicing the shell with a sequence of parallel plane pairs), with constant dipole moment per unit length (circumferentially) directed parallel to the propagation direction. The distributed source is represented by N dipoles at equal arc lengths along the belt. The sum of the dipole potentials is calculated at predefined electrode locations. The inverse problem involves finding a single equivalent point dipole that best reproduces the electrode potentials due to the distributed source. The inverse problem is implemented by minimising the chi2 per degree of freedom. It is found that the trajectory traced by the equivalent dipole is sensitive to the location of the spherical shell relative to the fixed electrodes. It is shown that this trajectory does not coincide with the sequence of geometrical centres of the consecutive belt sources. For distributed sources within a bounded spherical medium, displaced from the sphere's centre by 40% of the sphere's radius, it is found that the error in the equivalent dipole location varies from 3 to 20% for sources with size between 5 and 50% of the sphere's radius. Finally, a method is devised to obtain the size of the distributed source during the cardiac cycle.
7. Light bending by nonlinear electrodynamics under strong electric and magnetic field
SciTech Connect
Kim, Jin Young; Lee, Taekoon E-mail: [email protected]
2011-11-01
We calculate the bending angles of light under the strong electric and magnetic fields by a charged black hole and a magnetized neutron star according to the nonlinear electrodynamics of Euler-Heisenberg interaction. The bending angle of light by the electric field of charged black hole is computed from geometric optics and a general formula is derived for light bending valid for any orientation of the magnetic dipole. The astronomical significance of the light bending by magnetic field of a neutron star is discussed.
8. Experimental determination of the magnetic dipole moment of candidate magnetoreceptor cells in trout
NASA Astrophysics Data System (ADS)
Winklhofer, M.; Eder, S.; Cadioiu, H.; McNaughton, P. A.; Kirschvink, J. L.
2011-12-01
Based on histological, physiological, and physical evidence, Walker et al (1997) and Diebel et al (2000) have identified distinctive cells in the olfactory epithelium of the rainbow trout (Onchorynchus mykiss) that contain magnetite and are closely associated with neurons that respond to changes in magnetic field. To put biophysical constraints on the possible transduction mechanism of magnetic signals, and in particular, to find out if the intracellular magnet is free to rotate or rather firmly anchored within the cell body, we have studied the magneto-mechanical response of isolated candidate receptor cells in suspension using a light microscope equipped with two pairs of Helmholtz coils. From the characteristic re-orientation time of suspended cells after a change in magnetic field direction, we have determined the magnitude of the magnetic dipole moment of the cells in function of the external field strength (0.4 mT to 3.2 mT) in order to find out whether or not the natural magnetic moment is remanence-based or induced (i.e., single-domain vs. superparamagnetic/multi-domain). Results: 1) The mechanical response of isolated cells to a change in magnetic field direction was always immediate, irrespective of the direction of change, which implies that the intracellular magnet is not free to rotate in the cell, but rather rigidly attached, probably to the plasma membrane, which is also suggested by our confocal fluorescence-microscope studies. 2) The cellular dipole moment turned out to be independent of the external field strength. Thus, the natural magnetic dipole moment is based on magnetic remanence, which points to single-domain particles and corroborates the results by Diebel et al (2000), who obtained switching fields consistent with single-domain magnetite. 3). The magnetic dipole moment is found to be of the order of several tens of fAm2, which greatly exceeds previous estimates (0.5 fAm2), and thus is similar to values reported for the most strongly magnetic types of magnetotactic bacteria (Hanzlik et al. 2002). Our results demonstrate that the magnetically identified cells clearly meet the physical requirements for a magnetoreceptor capable of rapidly detecting small changes in the external magnetic field. Diebel, C.E., Proksch, R., Green, C.R., Neilson, P. & Walker, M.M. (2000) Magnetite defines a vertebrate magnetoreceptor. Nature 406, 299-302. Hanzlik, M., Winklhofer, M., Petersen, N. (2002) Pulsed-field-remanence measurements on individual magnetotactic bacteria, J. Magn. Magn. Mater., 248(2), 258-267. Walker, M.M., Diebel, C.E., Haugh, C.V., Pankhurst, P.M., Montgomery, J.C. & Green, C.R. (1997) Structure and function of the vertebrate magnetic sense. Nature 390, 371-376.
9. Axisymmetric p-mode pulsations of stars with dipole magnetic fields
NASA Astrophysics Data System (ADS)
Saio, Hideyuki; Gautschy, Alfred
2004-05-01
The effect of a dipole magnetic field on adiabatic axisymmetric non-radial p-mode pulsations is studied numerically. The angular dependence of pulsation, which cannot be represented by a single spherical harmonic in the presence of a magnetic field, is expanded into a series of spherical harmonics with different degrees l. The presence of a magnetic field not only shifts the pulsation frequency, the pulsations are also damped due to the generation of magnetic slow waves. In agreement with the results of Cunha & Gough, who used a different approach from ours, we find that the effect of a magnetic field on the intermediate-to-high-order p-modes is not monotonic but cyclic with respect to the pulsation frequency and the magnetic field strength. The damping rate of a high-order p-mode becomes very small at about 3 kG and 8 kG; the corresponding field strengths are higher for lower overtones. The diminished magnetic damping is favourable for the corresponding modes, if they are excited by the classical κ-mechanism, to survive even in the presence of a strong magnetic field. This picture could explain the mode selection as observed in the rapidly oscillating Ap stars. For a low-order p-mode, the damping rate increases as the strength of the magnetic field increases. We find that in the presence of a magnetic field of a few kG, magnetic damping seems to exceed the driving owing to the κ-mechanism of oscillations representative of δ Scuti variability. This may explain why δ Scuti-type oscillations are unlikely to be seen in magnetic Ap stars. The amplitude of a mainly dipole (or quadrupole) mode is strongly confined to the magnetic axis in the outer layers. Furthermore, horizontal motion can be comparable to radial motion even for high-order p-modes. We discuss the influence of the magnetic distortion of the eigenfunction on the pulsation amplitude modulation with respect to the rotation phase.
10. Interferometric methods for mapping static electric and magnetic fields
NASA Astrophysics Data System (ADS)
Pozzi, Giulio; Beleggia, Marco; Kasama, Takeshi; Dunin-Borkowski, Rafal E.
2014-02-01
The mapping of static electric and magnetic fields using electron probes with a resolution and sensitivity that are sufficient to reveal nanoscale features in materials requires the use of phase-sensitive methods such as the shadow technique, coherent Foucault imaging and the Transport of Intensity Equation. Among these approaches, image-plane off-axis electron holography in the transmission electron microscope has acquired a prominent role thanks to its quantitative capabilities and broad range of applicability. After a brief overview of the main ideas and methods behind field mapping, we focus on theoretical models that form the basis of the quantitative interpretation of electron holographic data. We review the application of electron holography to a variety of samples (including electric fields associated with p-n junctions in semiconductors, quantized magnetic flux in superconductors and magnetization topographies in nanoparticles and other magnetic materials) and electron-optical geometries (including multiple biprism, amplitude and mixed-type set-ups). We conclude by highlighting the emerging perspectives of (i) three-dimensional field mapping using electron holographic tomography and (ii) the model-independent determination of the locations and magnitudes of field sources (electric charges and magnetic dipoles) directly from electron holographic data.
11. A dominant magnetic dipole for the evolved Ap star candidate EK Eridani
NASA Astrophysics Data System (ADS)
Aurière, M.; Konstantinova-Antova, R.; Petit, P.; Roudier, T.; Donati, J.-F.; Charbonnel, C.; Dintrans, B.; Lignières, F.; Wade, G. A.; Morgenthaler, A.; Tsvetkova, S.
2011-10-01
Context. EK Eri is one of the most slowly rotating active giants known, and has been proposed to be the descendant of a strongly magnetic Ap star. Aims: We have performed a spectropolarimetric study of EK Eri over 4 photometric periods with the aim of inferring the topology of its magnetic field. Methods: We used the NARVAL spectropolarimeter at the Bernard Lyot telescope at the Pic du Midi Observatory, along with the least-squares deconvolution method, to extract high signal-to-noise ratio Stokes V profiles from a timeseries of 28 polarisation spectra. We have derived the surface-averaged longitudinal magnetic field Bℓ. We fit the Stokes V profiles with a model of the large-scale magnetic field and obtained Zeeman Doppler images of the surface magnetic strength and geometry. We studied the classical activity indicators, the Ca ii H and K lines, the Ca ii infrared triplet, and Hα line, as well as the stellar radial velocity. Results: Bℓ variations of up to about 80 G are observed without any reversal of its sign, and which are in phase with photometric ephemeris. The activity indicators are shown to vary smoothly on a timescale compatible with the rotational period inferred from photometry (308.8 d), however large deviations can occur from one rotation to another. The surface magnetic field variations of EK Eri appear to be dominated by a strong magnetic spot (of negative polarity) which is phased with the dark (cool) photometric spot. Our modeling shows that the large-scale magnetic field of EK Eri is strongly poloidal. For a rotational axis inclination of i = 60°, we obtain a model that is almost purely dipolar. Conclusions: In the dipolar model, the strong magnetic/photometric spot corresponds to the negative pole of the dipole, which could be the remnant of that of an Ap star progenitor of EK Eri. Our observations and modeling conceptually support this hypothesis, suggesting an explanation of the outstanding magnetic properties of EK Eri as the result of interaction between deep convection and the remnant of an Ap star magnetic dipole. Nevertheless, the longitudinal magnetic field curve clearly shows changes from one rotation to the next, indicating that the surface magnetic topology is not static as in an Ap star. Based on data obtained using the Télescope Bernard Lyot at Observatoire du Pic du Midi, CNRS/INSU and Université de Toulouse, France.
12. Combined Panofsky Quadrupole & Corrector Dipole
SciTech Connect
George Biallas; Nathan Belcher; David Douglas; Tommy Hiatt; Kevin Jordan
2007-07-02
Two styles of Panofsky Quadrupoles with integral corrector dipole windings are in use in the electron beam line of the Free Electron Laser at Jefferson Lab. We combined steering and focusing functions into single magnets, adding hundreds of Gauss-cm dipole corrector capability to existing quadrupoles because space is at a premium along the beam line. Superposing a one part in 100 dipole corrector field on a 1 part in 1000, weak (600 to 1000 Gauss) quadrupole is possible because the parallel slab iron yoke of the Panofsky Quadrupole acts as a window frame style dipole yoke. The dipole field is formed when two electrically floating “current sources”, designed and made at JLab, add and subtract current from the two opposite quadrupole current sheet windings parallel to the dipole field direction. The current sources also drive auxiliary coils at the yoke’s inner corners that improve the dipole field. Magnet measurements yielded the control system field maps that characterize the two types of fields. Field analysis using TOSCA, construction and wiring details, magnet measurements and reference for the current source are presented.
13. Surface temperature of a magnetized neutron star and interpretation of the ROSAT data. 1: Dipole fields
NASA Technical Reports Server (NTRS)
Page, Dany
1995-01-01
We model the temperature distribution at the surface of a magnetized neutron star and study the effects on the observed X-ray spectra and light curves. Generalrelativistic effects, i.e., redshift and lensing, are fully taken into account. Atmospheric effects on the emitted spectral flux are not included: we consider only blackbody emission at the local effective temperature. In this first paper we restrict ourselves to dipole fields. General features are studied and compared with the ROSAT data from the pulsars 0833 - 45 (Vela), 0656 + 14, 0630 + 178 (Geminga), and 1055 - 52, the four cases for which there is strong evidence that thermal radiation from the stellar surface is detected. The composite spectra we obtain are not very different from a blackbody spectrum at the star's effective temperature. We conclude that, as far as blackbody spectra are considered, temperature estimates using single-temperature models give results practically identical to our composite models. The change of the (composite blackbody) spectrum with the star's rotational phase is also not very large and may be unobservable inmost cases. Gravitational lensing strongly suppresses the light curve pulsations. If a dipole field is assumed, pulsed fractions comparable to the observed ones can be obtained only with stellar radii larger than those which are predicted by current models of neutron star struture, or with low stellar masses. Moreover, the shapes of the theoretical light curves with dipole fields do not correspond to the observations. The use of magnetic spectra may raise the pulsed fraction sufficiently but will certainly make the discrepancy with the light curve shapes worse: dipole fields are not sufficient to interpret the data. Many neutron star models with a meson condensate or hypersons predict very small radii, and hence very strong lensing, which will require highly nondipolar fields to be able to reproduce the observed pulsed fractions, if possible at all: this may be a new tool to constrain the size of neutron stars. The pulsed fractions obtained in all our models increase with photon energy: the strong decrease observed in Geminga at energies 0.3-0.5 keV is definitely a genuine effect of the magnetic field on the spectrum in contradistinction to the magnetic effects on the surface temperature considered her. Thus, a detailed analysis of thermal emission from the four pulsars we consider will require both complex surface field configurations and the inclusion of magnetic effects in the atmosphere (i.e., on the emitted spectrum).
14. Spectrum of relativistic radiation from electric charges and dipoles as they fall freely into a black hole
SciTech Connect
Shatskiy, A. A. Novikov, I. D.; Lipatova, L. N.
2013-06-15
The motion of electric charges and dipoles falling radially and freely into a Schwarzschild black hole is considered. The inverse effect of the electromagnetic fields on the black hole is neglected. Since the dipole is assumed to be a point particle, the deformation due to the action of tidal forces on it is neglected. According to the theorem stating that 'black holes have no hair', the multipole electromagnetic fields should be completely radiated as a multipole falls into a black hole. The electromagnetic radiation power spectrum for these multipoles (a monopole and a dipole) has been found. Differences have been found in the spectra for different orientations of the falling dipole. A general method has been developed to find the radiated multipole electromagnetic fields for multipoles (including higher-order multipoles-quadrupoles, etc.) falling freely into a black hole. The calculated electromagnetic spectra can be compared with observational data from stellar-mass and smaller black holes.
15. Towards the Measurement of the Electric-Dipole Moment of Radioactive Francium using Laser-Cooling and Trapping Techniques
NASA Astrophysics Data System (ADS)
Kawamura, Hirokazu; Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Inoue, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Uchiyama, A.; Aoki, T.; Furukawa, T.; Hatakeyama, A.; Hatanaka, K.; Imai, K.; Murakami, T.; Nataraj, H. S.; Sato, T.; Shimizu, Y.; Wakasa, T.; Yoshida, H. P.; Sakemi, Y.
An experiment to search for the electron electric dipole moment using francium is planned to test the new physics beyond the standard model. The optical lattice trapping of the francium that is produced through the nuclear fusion reaction at high heat may allow for a precise measurement of the electric dipole moment. The magneto-optical trapping of the francium is required as a precooling treatment. The factory of laser-cooled francium atoms has been developed for the magneto-optical trap. Currently, the apparatus that is able to trap a few atoms is constructed to identify the resonant frequency of francium.
16. Are you positive? Electric dipole polarity discrimination in the yellow stingray, Urobatis jamaicensis.
PubMed
Siciliano, Avery M; Kajiura, Stephen M; Long, John H; Porter, Marianne E
2013-10-01
It is well established that elasmobranchs can detect dipole electric fields. However, it is unclear whether they can discriminate between the anode and cathode. To investigate this subject, we employed a behavioral assay to determine the discriminatory ability of the yellow stingray, Urobatis jamaicensis. We conditioned stingrays with food rewards to bite either the anode (n=5) or the cathode (n=6) of a direct-current dipole located on the floor of an experimental tank. All individuals successfully performed the task after 18 to 22 days. Stingrays were then tested in experimental sessions when they were rewarded only after they identified the correct pole. Stingrays successfully discriminated between the poles at a rate greater than chance, ranging among individuals from a mean of 66% to 93% correct. During experimental sessions, stingrays conditioned to distinguish the anode performed similarly to those conditioned to distinguish the cathode. We hypothesize that the ability to discriminate anode from cathode is physiologically encoded, but its utility in providing spatial information under natural conditions remains to be demonstrated. The ability to discriminate polarity may eliminate ambiguity in induction-based magnetoreception and facilitate navigation with respect to the geomagnetic field. PMID:24243961
17. Laser Cooled Francium Factory for the Electron Electric Dipole Moment Search
NASA Astrophysics Data System (ADS)
Hayamizu, Tomohiro; Arikawa, Hiroshi; Ezure, Saki; Harada, Ken-ichi; Inoue, Takeshi; Ishikawa, Taisuke; Itoh, Masatoshi; Kato, Tomohiro; Kawamura, Hirokazu; Sato, Tomoya; Ando, Shun; Aoki, Takahiro; Kato, Ko; Uchiyama, Aiko; Aoki, Takatoshi; Furukawa, Takeshi; Hatakeyama, Atsushi; Hatanaka, Kichiji; Imai, Kenichi; Murakami, Tetsuya; Nataraj, Huliyar; Shimizu, Yasuhiro; Wakasa, Tomotsugu; Yoshida, Hidetomo; Sakemi, Yasuhiro
A permanent electric dipole moment (EDM) of an elementary particle is a candidate observable exhibiting CP violation beyond the standard model. In the present study, we plan to search for the electron EDM in francium (Fr), which is the heaviest alkali atom, captured in a far-off resonance optical trap. Since the number of Fr atoms is essential to high precision measurements, we have developed a cold Fr source called "Laser cooled Fr factory" in order to trap the radioactive Fr produced through a nuclear fusion reaction. The Fr produced was released as an ion from a gold production target in a Fr ion source, transported as an ion beam, and converted from ion to atom in a neutralizer. The neutralized Fr atom will be trapped in a magneto-optical trap(MOT) and then be transferred to an optical dipole trap. The rate of Fr atoms so far achieved was 1 × 106 ions/sec from the ion source and 1 atom/sec of the neutralized Fr atom from the neutralizer. In order to optimize performance of the Fr beam line, Rb atoms were trapped in the MOT. In addition to the beam-line experiment, in an off-line MOT system, polarization gradient cooling was applied to the trapped Rb atoms to cool them down to temperatures lower than the Rb Doppler-cooling limit. In this paper, we describe the present status of this experimental apparatus.
18. Search for the electron electric dipole moment using ?-doublet levels in PbO
NASA Astrophysics Data System (ADS)
Eckel, S.; Hamilton, P.; Kirilov, E.; Smith, H. W.; DeMille, D.
2013-05-01
We present results of an experiment to probe for the electric dipole moment (EDM) of the electron using an ?-doublet state in a polar molecule. If the molecule is both massive and has a large molecular-fixed frame dipole moment, then the ?-doublet states have the potential to greatly increase the sensitivity of experiments searching for the EDM while also allowing for new methods of systematic error rejection. Here, we use the metastable a(1)3?+ state of lead monoxide (PbO) to probe for the electron EDM. Our best fit for the electron EDM of de=(-4.49.5stat1.8syst)10-27ecm allows us to place an upper limit on the magnitude of the EDM of |de|<1.710-26ecm (90% confidence). While this is less stringent than limits from other, previous experiments, our work emphasizes the systematic error rejection properties associated with the ?-doublet level structure. The results should inform the work of other, ongoing experiments that use molecules with analogous level structure.
19. Implications of R-parity violating supersymmetry for atomic and hadronic electric dipole moments
SciTech Connect
Faessler, Amand; Gutsche, Thomas; Lyubovitskij, Valery E.; Kovalenko, Sergey
2006-10-01
We calculate the electric dipole moments (EDM) of the neutral {sup 199}Hg atom, deuteron, nucleons and neutral hyperons {lambda}, {sigma}{sup 0} and {xi}{sup 0} in the framework of a generic SUSY model without R-parity conservation (Re{sub p}SUSY) on the basis of the SU(3) version of chiral perturbation theory (ChPT). We consider CP-violation in the hadronic sector induced by the chromoelectric quark dipole moments and CP-violating 4-quark effective interactions. From the null experimental results on the neutron and {sup 199}Hg atom EDMs we derive limits on the imaginary parts of certain products Im({lambda}{sup '}{lambda}{sup '}*) of the trilinear Re{sub p}-couplings and demonstrate that they are more stringent than those existing in the literature. Using these limits we give predictions for the EDMs of neutral hyperons. We also estimate the prospects of future storage ring experiments on the deuteron EDM and show that the expected improvement of the above limits in these experiments may reach several orders of magnitude.
20. Equivalent dipole source imaging of brain electric activity by means of parametric projection filter.
PubMed
Hori, J; He, B
2001-05-01
In the present study, spatial filters for inverse estimation of an equivalent dipole layer from the scalp-recorded potentials have been explored for their suitability in achieving high-resolution electroencephalogram (EEG) imaging. The performance of the parametric projection filter (PPF), which we propose to use for high-resolution EEG imaging, has been evaluated by computer simulations in the presence of a priori information on noise. An inhomogeneous three-concentric-sphere head model was used in the present simulation study to represent the head volume conductor. An equivalent dipole layer was used to model brain electric sources and estimated from the scalp potentials. Various noise conditions were simulated and the parametric projection filter was compared with standard regularization procedures such as the truncated singular value decomposition (TSVD) and the Tikhonov regularization (TKNV). The present simulation results suggest that the proposed method performs better than that of commonly used inverse regularization techniques, such as the general inverse using the TSVD and the TKNV, when the correlation between the original source distribution and the noise distribution is low, and performs similarly when the correlation is high. A method for determining the optimum regularization parameter, which can be applied to parametric inverse techniques, has also been developed. PMID:11400724
1. Static Electric Dipole Polarizabilities of Tri- and Tetravalent U, Np, and Pu Ions
SciTech Connect
Parmar, Payal; Peterson, Kirk A.; Clark, Aurora E.
2013-11-21
High-quality static electric dipole polarizabilities have been determined for the ground states of the hard-sphere cations of U, Np, and Pu in the III and IV oxidation states. The polarizabilities have been calculated using the numerical finite field technique in a four-component relativistic framework. Methods including Fock-space coupled cluster (FSCC) and Kramers-restricted configuration interaction (KRCI) have been performed in order to account for electron correlation effects. Comparisons between polarizabilities calculated using Dirac-Hartree-Fock (DHF), FSCC, and KRCI methods have been made using both triple- and quadruple-ζ basis sets for U⁴⁺. In addition to the ground state, this study also reports the polarizability data for the first two excited states of U3+/4+, Np3+/4+, and Pu3+/4+ ions at different levels of theory. The values reported in this work are the most accurate to date calculations for the dipole polarizabilities of the hard-sphere tri- and tetravalent actinide ions and may serve as reference values, aiding in the calculation of various electronic and response properties (for example, intermolecular forces, optical properties, etc.) relevant to the nuclear fuel cycle and material science applications.
2. Design, Fabrication, and Test of a Superconducting Dipole Magnet Based on Tilted Solenoids
SciTech Connect
Caspi, S.; Dietderich, D. R.; Ferracin, P.; Finney, N. R.; Fuery, M. J.; Gourlay, S. A.; Hafalia, A. R.
2007-06-01
It can be shown that, by superposing two solenoid-like thin windings that are oppositely skewed (tilted) with respect to the bore axis, the combined current density on the surface is 'cos-theta' like and the resulting magnetic field in the bore is a pure dipole. As a proof of principle, such a magnet was designed, built and tested as part of a summer undergraduate intern project. The measured field in the 25mm bore, 4 single strand layers using NbTi superconductor, exceeded 1 T. The simplicity of this high field quality design, void of typical wedges end-spacers and coil assembly, is especially suitable for insert-coils using High Temperature Superconducting wire as well as for low cost superconducting accelerator magnets for High Energy Physics. Details of the design, construction and test are reported.
3. Relativistic charged particle in magnetic dipole-spherical geometry. III. Local three-dimensional states
SciTech Connect
Gopinath, K.S.; Kennedy, D.C.; Gelb, J.M.
1997-07-01
Following two previous papers, we examine single- and many-body states of relativistic charged particles in an intense, rotating magnetic dipole field. Single-body orbits are derived classically and semiclassically, and then applied to the many-body orbits are derived classically and semiclassically, and then applied to the many-body case via the Thomas-Fermi approximation. Examples of electrons in a realistic neutron star crust are considered with both fixed density profiles and constant Fermi energy. In the first case, the varying magnetic field and Coriolis correction lead to a varying Fermi energy and macroscopic currents; in the second, the electron density is redistributed by the magnetic field. Further questions are outlined. 16 refs., 10 figs.
4. Design and Fabrication of a 14 T, Nb3Sn Superconducting Racetrack Dipole Magnet
SciTech Connect
Gourlay, S.A.; Bish, P.; Caspi, S.; Chow, K.; Dietderich, D.R.; Gupta, R.; Hannaford, R.; Harnden, W.; Higley, H.; Lietzke, A.; Liggins, N.; McInturff, A.D.; Millos, G.A.; Morrison, L. Morrison M.; Scanlan, R.M.
1999-09-01
Most accelerator magnets for applications in the field range up to 10 T utilize NbTi superconductor and a cosine theta coil design. For fields above 10 T, it is necessary to use Nb{sub 3}Sn or other strain sensitive superconductors land other coil geometries that are more compatible with these materials. This paper describes our recent efforts to design a series of racetrack coil magnets that will provide experimental verification of an alternative magnet design philosophy, with the near-term goal of reaching a field level of approximately 14 T. The conductor and fabrication issues relevant to building high field, racetrack dipoles utilizing Nb{sub 3}Sn superconductor and a wind and react approach will also be discussed.
5. Effect of core polarization on magnetic dipole moments in deformed odd-mass nuclei
NASA Astrophysics Data System (ADS)
Bonneau, L.; Minkov, N.; Duc, Dao Duy; Quentin, P.; Bartel, J.
2015-05-01
Magnetic properties of deformed odd-mass nuclei are studied within a nonrelativistic mean-field-plus-pairing approach, namely the Skyrme-Hartree-Fock-BCS approach with self-consistent blocking. For an odd number of nucleons these approaches lead to the breaking of the time-reversal invariance. The deviation from the Schmidt values of the isoscalar magnetic dipole moment is known to result from a subtle balance between core-polarization effects and meson-exchange current effects. However, the former are usually calculated in the random phase approximation without time-reversal symmetry breaking at the mean-field level. In this work we show that if one takes into account this symmetry breaking already in the mean-field solution, the correction from core polarization yields a significant contribution to the empirical quenching of the spin gyromagnetic ratios as compared to the free values in deformed odd-mass nuclei. Moreover, we calculate magnetic dipole moments in the Bohr and Mottelson unified-model description with self-consistent blocked mean-field intrinsic states. The obtained results in the A ˜100 and A ˜180 mass regions as well as for three actinide nuclei compare favorably with experimental data.
6. Material Procurement Report for the FNAL pp Forward Detector's Toroids and Cos8 Dipole Magnets
SciTech Connect
Cline, D.; Morse, R.; Orosz, I.; Thomas, L.C.;
1980-10-27
We outline the possibilities of starting construction of the {bar p}p forward detector toroids and cos{theta} dipole magnets described in CDP Note 64 as soon as possible using material that already exists on the FNAL site. Personal inspection of the steel supplies indicates that as much as 2000 tons of steel or over 50% of all the steel needed for the toroids is now available at the FNAL boneyard. Copper inventories indicate that there is enough copper on the FNAL site to construct both the toroid magnets and the cos{theta} dipole magnets. A construction schedule of one toroid in FY81, two toroids in FY82, and the final toroid in FY83 is shown to be feasible. Floor space and loading requirements for the IR Hall housing the forward detector are examined and finally, budgets for the initial FY8l phase and the completed project are given. The FY81 costs are $393K and to-completion costs are$1506K.
7. Electric-field guiding of magnetic skyrmions
NASA Astrophysics Data System (ADS)
Upadhyaya, Pramey; Yu, Guoqiang; Amiri, Pedram Khalili; Wang, Kang L.
2015-10-01
We theoretically study equilibrium and dynamic properties of nanosized magnetic skyrmions in thin magnetic films with broken inversion symmetry, where an electric field couples to magnetization via spin-orbit coupling. Based on a symmetry-based phenomenology and micromagnetic simulations we show that this electric-field coupling, via renormalizing the micromagnetic energy, modifies the equilibrium properties of the skyrmion. This change, in turn, results in a significant alteration of the current-induced skyrmion motion. Particularly, the speed and direction of the skyrmion can be manipulated by designing a desired energy landscape electrically, which we describe within Thiele's analytical model and demonstrate in micromagnetic simulations including electric-field-controlled magnetic anisotropy. We additionally use this electric-field control to construct gates for controlling skyrmion motion exhibiting a transistorlike and multiplexerlike function. The proposed electric-field effect can thus provide a low-energy electrical knob to extend the reach of information processing with skyrmions.
8. Dissipation of energy in model experiments. [plasma interaction with magnetic dipole
NASA Technical Reports Server (NTRS)
Podgornyy, I. M.
1974-01-01
Interaction studies of a plasma stream with a magnetic dipole have shown that the thickness of the plasma/field interlayer is considerably greater than the characteristic plasma dimension c/omega sub 0. Broadening of the layer is due to the formation of a collisionless shock wave. To demonstrate collisionless dissipation, the Joulean losses were calculated using the conductivity value obtained from the skin layer thickness. Analysis of the various physical processes showed that the hypothesis of collisionless dissipation of the directional plasma flow is justified.
9. Temperature-dependent terahertz magnetic dipole radiation from antiferromagnetic GdFeO{sub 3} ceramics
SciTech Connect
Fu, Xiaojian; Xi, Xiaoqing; Bi, Ke; Zhou, Ji
2013-11-18
Temperature-dependent terahertz magnetic dipole radiation in antiferromagnetic GdFeO{sub 3} ceramic is investigated both theoretically and experimentally in this work. A two-level quantum transition mechanism is introduced to describe the excitation-radiation process, and radiative lifetime is derived analytically from the change of spin state density during this process. Terahertz spectral measurements demonstrate that the radiative frequency exhibits a red-shift and lifetime shortens as temperature increases, which is in good agreement with theoretical predictions. The temperature-sensitive radiative frequency and excellent terahertz emission mean that the antiferromagnetic ceramics show potential for application in terahertz sensors and frequency-tunable terahertz lasers.
10. New method to determine proton trajectories in the equatorial plane of a dipole magnetic field.
PubMed
Ioanoviciu, Damaschin
2015-01-01
A parametric description of proton trajectories in the equatorial plane of Earth's dipole magnetic field has been derived. The exact expression of the angular coordinate contains an integral to be performed numerically. The radial coordinate results from the initial conditions by basic mathematical operations and by using trigonometric functions. With the approximate angular coordinate formula, applicable for a wide variety of cases of protons trapped in Earth's radiation belts, no numerical integration is needed. The results of exact and approximate expressions were compared for a specific case and small differences were found. PMID:25815248
11. A D-He/sup 3/ fusion reactor based on a dipole magnetic field
SciTech Connect
Hasegawa, Akira; Chen, Liu
1989-07-01
An innovative fusion reactor suitable for D-He/sup 3/ fuel is proposed, based on a dipole magnetic field produced by a simple one-turn coil with /approx lt/16 T near-field intensity. The equilibrium plasma, phase-space density satisfies /partial derivative//cflx f//sub 0/(/mu/, J, /psi/)//partial derivative//psi/ = O, where /psi/ is the flux function, has a steep enough pressure profile for an efficient fusion reaction yet is stable for low frequency instabilities to local beta exceeding unity. The semi-open field configuration is particularly suitable for D-He/sup 3/ reactions. 8 refs., 1 fig.
12. Quench problems of Nb3 Sn cosine theta high field dipole model magnets
SciTech Connect
Yamada, Ryuji; Wake, Masayoshi; /KEK, Tsukuba
2004-12-01
We have developed and tested several cosine theta high field dipole model magnets for accelerator application, utilizing Nb{sub 3}Sn strands made by MJR method and PIT method. With Rutherford cables made with PIT strand we achieved 10.1 Tesla central field at 2.2 K operation, and 9.5 Tesla at 4.5 K operation. The magnet wound with the MJR cable prematurely quenched at 6.8 Tesla at 4.5 K due to cryo-instability. Typical quench behaviors of these magnets are described for both types of magnets, HFDA-04 of MJR and HFDA-05 of PIT. Their characteristics parameters are compared on d{sub eff}, RRR, thermal conductivity and others, together with other historical Nb{sub 3}Sn magnets. It is suggested a larger RRR value is essential for the stability of the epoxy impregnated high field magnets made with high current density strands. It is shown that a magnet with a larger RRR value has a longer MPZ value and more stable, due to its high thermal conductivity and low resistivity.
13. Dipole Well Location
Energy Science and Technology Software Center (ESTSC)
1998-08-03
The problem here is to model the three-dimensional response of an electromagnetic logging tool to a practical situation which is often encountered in oil and gas exploration. The DWELL code provide the electromagnetic fields on the axis of a borehole due to either an electric or a magnetic dipole located on the same axis. The borehole is cylindrical, and is located within a stratified formation in which the bedding planes are not horizontal. The anglemore » between the normal to the bedding planes and the axis of the borehole may assume any value, or in other words, the borehole axis may be tilted with respect to the bedding planes. Additionally, all of the formation layers may have invasive zones of drilling mud. The operating frequency of the source dipole(s) extends from a few Hertz to hundreds of Megahertz.« less
14. Analysis of the AC loss measurements on the one-metre dipole model magnets for the CERN LHC
SciTech Connect
Verweij, A.P.; Leroy, D.; Walckiers, L.; Wolf, R.; Kate, H.H.J. ten
1994-07-01
Superconducting single and twin-aperture dipole model magnets for the future CERN Large Hadron Collider have been built in industry and tested at CERN. In this paper the results of AC loss measurements are presented that are performed on 6 magnets all having a bore of 50 mm diameter and coils wound of 17 mm wide superconducting cables. The cables that are used in these models differ with respect to the filament diameter, the strand coating and the fact whether the cable is (partially) soldered or not. The energy loss, determined electrically as the difference between the stored energy and the extracted energy during a current cycle, consists mainly of filament hysteresis and inter-strand coupling loss. The hysteresis component is in fair agreement with calculations. The inter-strand coupling loss varies with about a factor 5 between the models due to a different contact resistance between crossing strands in the cable (varying in the range from 1 to 10 {mu}{Omega}). Even for model magnets which are made with the same cable the inter-strand coupling loss can differ significantly.
15. Ultralight gravitons with tiny electric dipole moment are seeping from the vacuum
NASA Astrophysics Data System (ADS)
Novikov, Evgeny A.
2016-05-01
Mass and electric dipole moment (EDM) of graviton, which is identified as dark matter particle (DMP), are estimated. This change the concept of dark matter and can help to explain the baryon asymmetry of the universe. The calculations are based on quantum modification of the general relativity (Qmoger) with two additional terms in the Einstein equations, which takes into account production/absorption of gravitons. In this theory, there are no Big Bang in the beginning (some local bangs during the evolution of the universe are probable), no critical density of the universe, no dark energy (no need in cosmological constant) and no inflation. The theory (without fitting) is in good quantitative agreement with cosmic data.
16. Electric dipole moments of actinide atoms and RaO molecule
SciTech Connect
Flambaum, V. V.
2008-02-15
We have calculated the atomic electric dipole moments (EDMs) induced in {sup 229}Pa and {sup 225}Ac by their respective nuclear Schiff moments S. The results are d({sup 229}Pa)=-9.5x10{sup -17} [S/(e fm)]e cm=-1.1x10{sup -20}{eta} e cm and d({sup 225}Ac)=-8.6x10{sup -17} [S/(e fm)]e cm=-0.8x10{sup -21}{eta} e cm. EDM of {sup 229}Pa is 3x10{sup 4} times larger than {sup 199}Hg EDM and 40 times larger than {sup 225}Ra EDM. Possible use of actinides in solid state experiments is also discussed. The (T,P)-odd spin-axis interaction in RaO molecule is 500 times larger than in TlF.
17. Enhancement of the C P -odd effect in the nuclear electric dipole moment of 6Li
NASA Astrophysics Data System (ADS)
Yamanaka, Nodoka; Hiyama, Emiko
2015-05-01
We calculate for the first time the electric dipole moment (EDM) of the 6Li nucleus within the α +p +n three-body cluster model using the Gaussian expansion method, assuming the one-meson exchange P , CP-odd nuclear forces. It is found that the EDM of 6Li is 2 times more sensitive to the isovector pion exchange P , CP-odd nuclear force than the deuteron EDM because of the CP-odd interaction between the nucleons and the α cluster. The 9Be EDM is also calculated in the same framework as an α +α +n three-body system. We also test the ab initio calculation of the EDM of the deuteron, 3H , and 3He nuclei using the realistic Argonne v 18 nuclear force. In the ab initio calculations, good agreements with previous studies are obtained. We finally discuss the prospects for new physics beyond the standard model.
18. A New Measurement of the Electric Dipole Moment of the Muon
SciTech Connect
Carey, Robert M.
2009-12-17
Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Brief details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muon, as well as the combined result, d{sub {mu}} = (-0.1{+-}0.9)x10{sup -19} e{center_dot}cm, are all consistent with zero, we set a new muon EDM limit, |d{sub {mu}}|<1.9x10{sup -19} e{center_dot}cm(95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.
19. Revised experimental upper limit on the electric dipole moment of the neutron
NASA Astrophysics Data System (ADS)
Pendlebury, J. M.; Afach, S.; Ayres, N. J.; Baker, C. A.; Ban, G.; Bison, G.; Bodek, K.; Burghoff, M.; Geltenbort, P.; Green, K.; Griffith, W. C.; van der Grinten, M.; Grujić, Z. D.; Harris, P. G.; Hélaine, V.; Iaydjiev, P.; Ivanov, S. N.; Kasprzak, M.; Kermaidic, Y.; Kirch, K.; Koch, H.-C.; Komposch, S.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; May, D. J. R.; Musgrave, M.; Naviliat-Cuncic, O.; Piegsa, F. M.; Pignol, G.; Prashanth, P. N.; Quéméner, G.; Rawlik, M.; Rebreyend, D.; Richardson, J. D.; Ries, D.; Roccia, S.; Rozpedzik, D.; Schnabel, A.; Schmidt-Wellenburg, P.; Severijns, N.; Shiers, D.; Thorne, J. A.; Weis, A.; Winston, O. J.; Wursten, E.; Zejma, J.; Zsigmond, G.
2015-11-01
We present for the first time a detailed and comprehensive analysis of the experimental results that set the current world sensitivity limit on the magnitude of the electric dipole moment (EDM) of the neutron. We have extended and enhanced our earlier analysis to include recent developments in the understanding of the effects of gravity in depolarizing ultracold neutrons; an improved calculation of the spectrum of the neutrons; and conservative estimates of other possible systematic errors, which are also shown to be consistent with more recent measurements undertaken with the apparatus. We obtain a net result of dn=-0.21 ±1.82 ×1 0-26 e cm , which may be interpreted as a slightly revised upper limit on the magnitude of the EDM of 3.0 ×1 0-26 e cm (90% C.L.) or 3.6 ×1 0-26 e cm (95% C.L.).
20. Effects of confinement on the permanent electric-dipole moment of Xe atoms in liquid Xe
SciTech Connect
Ravaine, Boris; Derevianko, Andrei
2004-05-01
Searches for permanent electric-dipole moments (EDM) of atoms provide important constraints on competing extensions to the standard model of elementary particles. Recently proposed experiment with liquid {sup 129}Xe [M.V. Romalis and M.P. Ledbetter, Phys. Rev. Lett. 87, 067601 (2001)] may significantly improve present limits on the EDMs. To interpret experimental data in terms of CP-violating sources, one must relate measured atomic EDM to various model interactions via electronic-structure calculations. Here we study density dependence of atomic EDMs. The analysis is carried out in the framework of the cell model of the liquid coupled with relativistic atomic-structure calculations. We find that compared to an isolated atom, the EDM of an atom of liquid Xe is suppressed by about 40%.
1. P- and T-odd two-nucleon interaction and the deuteron electric dipole moment
SciTech Connect
Liu, C.-P.; Timmermans, R.G.E.
2004-11-01
The nuclear physics relevant to the electric dipole moment (EDM) of the deuteron is addressed. The general operator structure of the P- and T-odd nucleon-nucleon interaction is discussed and applied to the two-body contributions of the deuteron EDM, which can be calculated in terms of P- and T-odd meson-nucleon coupling constants with only small model dependence. The one-body contributions, the EDMs of the proton and the neutron, are evaluated within the same framework. Although the total theoretical uncertainties are sizable, we conclude that, compared to the neutron, the deuteron EDM is competitive in terms of sensitivity to CP violation, and complementary with respect to the microscopic sources of CP violation that can be probed.
2. Microgravity Electron Electric Dipole Moment Experiment with a Cold Atom Beam
NASA Technical Reports Server (NTRS)
Gould, Harvey
2003-01-01
New physics beyond the Standard Model: The small CP violation contained in the Standard Model is insufficient to account for the baryon/antibaryon asymmetry in the universe. New sources of CP violation are provided by extensions to the Standard Model. They contain CP-violating phases that couple directly to leptons and from which a large electron electric dipole moment (EDM) may be generated. Observation of an electron EDM would be proof of a Standard Model extension because the Standard Model only allows an electron EDM of less than 10(exppp -57) C-m (S.I. units; 1 C-m = 1.6 x 10(exp -21) e-cm). A null result, however, constrains models and improving the limit tightens constraints, further restricting the models.
3. Electric-dipole 5s - 5p Transitions in Promethiumlike Ions
SciTech Connect
Vilkas, M J; Ishikawa, Y; Trabert, E
2008-02-29
The 5s-5p electric-dipole resonance transitions in highly ionized promethiumlike ions have been studied applying relativistic multi-reference Moeller-Plesset second-order perturbation theory. The transition wavelengths are determined to within 0.2 {angstrom} in the more highly charged ions, where the level degeneracies are small. For somewhat lighter ions a very large reference space was used in order to account for the many degeneracies. In order to calculate transition probabilities and lifetimes, correlation corrections have been added to the transition operator in the next order. The contributions from the higher orders of the theory, that is, frequency-dependent Breit correction, Lamb shift, and mass shifts, have been estimated. The results are used to re-assess spectroscopic data from beam-foil, electron beam ion trap, and tokamak observations.
4. Electric Dipole Moments in Radioactive Nuclei, Tests of Time Reversal Symmetry
SciTech Connect
Auerbach, N.
2010-11-24
The research of radioactive nuclei opens new possibilities to study fundamental symmetries, such as time reversal and reflection symmetry. Such nuclei often provide conditions to check in an optimal way certain symmetries and the violation of such symmetries. We will discuss the possibility of obtaining improved limits on violation of time reversal symmetry using pear shaped radioactive nuclei. An effective method to test time reversal invariance in the non-strange sector is to measure parity and time reversal violating (T-P-odd) electromagnetic moments, (such as the static electric dipole moment). Parity and time reversal violating components in the nuclear force may produce P-T-odd moments in nuclei which in turn induce such moments in atoms. We will discuss the possibility that in some reflection asymmetric, heavy nuclei (which are radioactive) these moments are enhanced by several orders of magnitude. Present and future experiments, which will test this idea, will be mentioned.
5. Neutron and proton electric dipole moments from Nf=2 +1 domain-wall fermion lattice QCD
NASA Astrophysics Data System (ADS)
Shintani, Eigo; Blum, Thomas; Izubuchi, Taku; Soni, Amarjit; Rbc; Ukqcd Collaborations
2016-05-01
We present a lattice calculation of the neutron and proton electric dipole moments (EDMs) with Nf=2 +1 flavors of domain-wall fermions. The neutron and proton EDM form factors are extracted from three-point functions at the next-to-leading order in the θ vacuum of QCD. In this computation, we use pion masses of 0.33 and 0.42 GeV and 2.7 fm3 lattices with Iwasaki gauge action, and a 0.17 GeV pion and a 4.6 fm3 lattice with I-DSDR gauge action, all generated by the RBC and UKQCD collaborations. The all-mode averaging technique enables an efficient and high statistics calculation. Chiral behavior of lattice EDMs is discussed in the context of baryon chiral perturbation theory. In addition, we also show numerical evidence on the relationship of three- and two-point correlation functions with the local topological charge distribution.
6. A comparison of calculations and measurements of the field harmonics as a function of current in the SSC dipole magnets
SciTech Connect
Gupta, R.C.; Cottingham, J.G.; Kahn, S.A.; Morgan, G.H.; Wanderer, P.
1991-01-01
A large number of short and long superconducting dipole magnets for the Superconducting Super Collider (SSC) have been constructed and measured for their magnetic field properties at Brookhaven National Laboratory (BNL). In this paper we compare the calculations and measurements for the variation of field harmonics as a function of current in 40 mm aperture and 50 mm aperture dipole magnets. The primary purpose of this paper is to examine the iron saturation effects on the field harmonics. The field harmonics also change due to the persistent current in the superconducting wires and due to the deformation of the coil shape because of Lorentz forces. We discuss the variation in the sextupole harmonics (b{sub 2}) with current and explain the differences between the calculations and measurements. We also discuss the skew quadrupole harmonic at high field in the long dipole magnets. 3 refs., 3 figs., 1 tab.
7. Status of 4-cm-aperture, 17-m-long SSC dipole magnet R D program at BNL
SciTech Connect
Devred, A.; Bush, T.; Coombes, R.; DiMarco, J.; Goodzeit, C.; Kuzminski, J.; Puglisi, M.; Radusewicz, P.; Sanger, P.; Schermer, R.; Tompkins, J.; Turner, J.; Wolf, Z.; Yu, Y.; Zheng, H. ); Ogitsu, T. National Lab. for High Energy Physics, Tsukuba, Ibaraki ); Anerella, M.; Cottin
1991-03-01
Over the last year, several 4-cm-aperture, 17-m-long dipole magnet prototypes were built by Brookhaven National Laboratory (BNL) under contract with the Superconducting Super Collider (SSC) Laboratory. These prototypes are the last phase of a half-decade-long R D program, carried out in collaboration with Fermi National Accelerator Laboratory and Lawrence Berkeley Laboratory, and aimed at demonstrating the feasibility of the SSC main ring magnets. They also lay the ground for the 5-cm aperture dipole magnet program to be started soon. After reviewing the design features of the BNL 4-cm-aperture, 17-m-long dipole magnets, we describe in detail the various steps of their fabrication. For each step, we discuss the parameters that need to be mastered, and we compare the values that were achieved for the five most recent prototypes. The data appear coherent and reproducible, demonstrating that the assembly process in under control. 23 refs., 10 figs., 4 tabs.
8. Exploratory conformational study of (+)-catechin. Modeling of the polarizability and electric dipole moment.
PubMed
Bentz, Erika N; Pomilio, Alicia B; Lobayan, Rosana M
2014-12-01
The extension of the study of the conformational space of the structure of (+)-catechin at the B3LYP/6-31G(d,p) level of theory is presented in this paper. (+)-Catechin belongs to the family of the flavan-3-ols, which is one of the five largest phenolic groups widely distributed in nature, and whose biological activity and pharmaceutical utility are related to the antioxidant activity due to their ability to scavenge free radicals. The effects of free rotation around all C-O bonds of the OH substituents at different rings are taken into account, obtaining as the most stable conformer, one that had not been previously reported. One hundred seven structures, and a study of the effects of charge delocalization and stereoelectronic effects at the B3LYP/6-311++G(d,p) level are reported by natural bond orbital analysis, streamlining the order of these structures. For further analysis of the structural and molecular properties of this compound in a biological environment, the calculation of polarizabilities, and the study of the electric dipole moment are performed considering the whole conformational space described. The results are analyzed in terms of accumulated knowledge for (4α → 6″, 2α → O → 1″)-phenylflavans and (+)-catechin in previous works, enriching the study of both types of structures, and taking into account the importance of considering the whole conformational space in modeling both the polarizability and the electric dipole moment, also proposing to define a descriptive subspace of only 16 conformers. PMID:25431187
9. Generation of Electric and Magnetic Fields During Detonation of High Explosive Charges in Boreholes
SciTech Connect
Soloviev, S; Sweeney, J
2004-06-04
We present experimental results of a study of electromagnetic field generation during underground detonation of high explosive charges in holes bored in sandy loam and granite. Test conditions and physico-mechanical properties of the soil exert significant influence on the parameters of electromagnetic signals generated by underground TNT charges with masses of 2 - 200 kg. The electric and magnetic field experimental data are satisfactorily described by an electric dipole model with the source embedded in a layered media.
10. Stress management as an enabling technology for high-field superconducting dipole magnets
NASA Astrophysics Data System (ADS)
Holik, Eddie Frank, III
This dissertation examines stress management and other construction techniques as means to meet future accelerator requirement demands by planning, fabricating, and analyzing a high-field, Nb3Sn dipole. In order to enable future fundamental research and discovery in high energy accelerator physics, bending magnets must access the highest fields possible. Stress management is a novel, propitious path to attain higher fields and preserve the maximum current capacity of advanced superconductors by managing the Lorentz stress so that strain induced current degradation is mitigated. Stress management is accomplished through several innovative design features. A block-coil geometry enables an Inconel pier and beam matrix to be incorporated in the windings for Lorentz Stress support and reduced AC loss. A laminar spring between windings and mica paper surrounding each winding inhibit any stress transferral through the support structure and has been simulated with ALGORRTM. Wood's metal filled, stainless steel bladders apply isostatic, surface-conforming preload to the pier and beam support structure. Sufficient preload along with mica paper sheer release reduces magnet training by inhibiting stick-slip motion. The effectiveness of stress management is tested with high-precision capacitive stress transducers and strain gauges. In addition to stress management, there are several technologies developed to assist in the successful construction of a high-field dipole. Quench protection has been designed and simulated along with full 3D magnetic simulation with OPERARTM. Rutherford cable was constructed, and cable thermal expansion data was analysed after heat treatment. Pre-impregnation analysis techniques were developed due to elemental tin leakage in varying quantities during heat treatment from each coil. Robust splicing techniques were developed with measured resistivites consistent with nO joints. Stress management has not been incorporated by any other high field dipole research laboratory and has not yet been put to a definitive high-field test. The TAMU Physics Accelerator Research Laboratory has constructed a Nb 3Sn dipole, TAMU3, that is specially designed to provide a test bed for high-field stress management.
11. β-decay and the electric dipole moment: searches for time-reversal violation in radioactive nuclei and atoms
NASA Astrophysics Data System (ADS)
Wilschut, H. W.; van der Hoek, D. J.; Jungmann, K.; Kruithof, W.; Onderwater, C. J. G.; Santra, B.; Shidling, P.; Willmann, L.
2010-11-01
At the KVI preparations are underway to study time-reversal violation. We will discuss two complementary experiments: Correlations in β decay of 21Na and the search for an electric dipole moment in Radium. We discuss the complementarity of these measurements and put them in the context of current research.
12. Electromagnetic fields due to a horizontal electric dipole antenna laid on the surface of a two-layer medium
NASA Technical Reports Server (NTRS)
Tsang, L.; Kong, J. A.
1974-01-01
With applications to geophysical subsurface probings, electromagnetic fields due to a horizontal electric dipole laid on the surface of a two-layer medium are solved by a combination of analytic and numerical methods. Interference patterns are calculated for various layer thickness. The results are interpreted in terms of normal modes, and the accuracies of the methods are discussed.
13. TOPICAL REVIEW: Electrical polarization and orbital magnetization: the modern theories
NASA Astrophysics Data System (ADS)
Resta, Raffaele
2010-03-01
Macroscopic polarization P and magnetization M are the most fundamental concepts in any phenomenological description of condensed media. They are intensive vector quantities that intuitively carry the meaning of dipole per unit volume. But for many years both P and the orbital term in M evaded even a precise microscopic definition, and severely challenged quantum-mechanical calculations. If one reasons in terms of a finite sample, the electric (magnetic) dipole is affected in an extensive way by charges (currents) at the sample boundary, due to the presence of the unbounded position operator in the dipole definitions. Therefore P and the orbital term in M—phenomenologically known as bulk properties—apparently behave as surface properties; only spin magnetization is problemless. The field has undergone a genuine revolution since the early 1990s. Contrary to a widespread incorrect belief, P has nothing to do with the periodic charge distribution of the polarized crystal: the former is essentially a property of the phase of the electronic wavefunction, while the latter is a property of its modulus. Analogously, the orbital term in M has nothing to do with the periodic current distribution in the magnetized crystal. The modern theory of polarization, based on a Berry phase, started in the early 1990s and is now implemented in most first-principle electronic structure codes. The analogous theory for orbital magnetization started in 2005 and is partly work in progress. In the electrical case, calculations have concerned various phenomena (ferroelectricity, piezoelectricity, and lattice dynamics) in several materials, and are in spectacular agreement with experiments; they have provided thorough understanding of the behaviour of ferroelectric and piezoelectric materials. In the magnetic case the very first calculations are appearing at the time of writing (2010). Here I review both theories on a uniform ground in a density functional theory (DFT) framework, pointing out analogies and differences. Both theories are deeply rooted in geometrical concepts, elucidated in this work. The main formulae for crystalline systems express P and M in terms of Brillouin-zone integrals, discretized for numerical implementation. I also provide the corresponding formulae for disordered systems in a single k-point supercell framework. In the case of P the single-point formula has been widely used in the Car-Parrinello community to evaluate IR spectra.
14. Correlation of superparamagnetic relaxation with magnetic dipole interaction in capped iron-oxide nanoparticles.
PubMed
Landers, J; Stromberg, F; Darbandi, M; Schöppner, C; Keune, W; Wende, H
2015-01-21
Six nanometer sized iron-oxide nanoparticles capped with an organic surfactant and/or silica shell of various thicknesses have been synthesized by a microemulsion method to enable controllable contributions of interparticle magnetic dipole interaction via tunable interparticle distances. Bare particles with direct surface contact were used as a reference to distinguish between interparticle interaction and surface effects by use of Mössbauer spectroscopy. Superparamagnetic relaxation behaviour was analyzed by SQUID-magnetometry techniques, showing a decrease of the blocking temperature with decreasing interparticle interaction energies kBT0 obtained by AC susceptibility. A many-state relaxation model enabled us to describe experimental Mössbauer spectra, leading to an effective anisotropy constant Keff ≈ 45 kJm(-3) in case of weakly interacting particles, consistent with results from ferromagnetic resonance. Our unique multi-technique approach, spanning a huge regime of characteristic time windows from about 10 s to 5 ns, provides a concise picture of the correlation of superparamagnetic relaxation with interparticle magnetic dipole interaction. PMID:25502104
15. Possible shape coexistence and magnetic dipole transitions in {sup 17}C and {sup 21}Ne
SciTech Connect
Sagawa, H.; Zhou, X. R.; Suzuki, Toshio; Yoshida, N.
2008-10-15
Magnetic dipole (M1) transitions of N=11 nuclei {sup 17}C and {sup 21}Ne are investigated by using shell model and deformed Skyrme Hartree-Fock + blocked BCS wave functions. Shell model calculations predict well observed energy spectra and magnetic dipole transitions in {sup 21}Ne, while the results are rather poor to predict these observables in {sup 17}C. In the deformed HF calculations, the ground states of the two nuclei are shown to have large prolate deformations close to {beta}{sub 2}=0.4. It is also pointed out that the first K{sup {pi}}=1/2{sup +} state in {sup 21}Ne is prolately deformed, while the first K{sup {pi}}=1/2{sup +} state in {sup 17}C is predicted to have a large oblate deformation close to the ground state in energy, We point out that the experimentally observed large hindrance of the M1 transition between I{sup {pi}}=1/2{sup +} and 3/2{sup +} in {sup 17}C can be attributed to a shape coexistence near the ground state of {sup 17}C.
16. Correlation of superparamagnetic relaxation with magnetic dipole interaction in capped iron-oxide nanoparticles
NASA Astrophysics Data System (ADS)
Landers, J.; Stromberg, F.; Darbandi, M.; Schöppner, C.; Keune, W.; Wende, H.
2015-01-01
Six nanometer sized iron-oxide nanoparticles capped with an organic surfactant and/or silica shell of various thicknesses have been synthesized by a microemulsion method to enable controllable contributions of interparticle magnetic dipole interaction via tunable interparticle distances. Bare particles with direct surface contact were used as a reference to distinguish between interparticle interaction and surface effects by use of Mössbauer spectroscopy. Superparamagnetic relaxation behaviour was analyzed by SQUID-magnetometry techniques, showing a decrease of the blocking temperature with decreasing interparticle interaction energies kBT0 obtained by AC susceptibility. A many-state relaxation model enabled us to describe experimental Mössbauer spectra, leading to an effective anisotropy constant Keff ≈ 45 kJm-3 in case of weakly interacting particles, consistent with results from ferromagnetic resonance. Our unique multi-technique approach, spanning a huge regime of characteristic time windows from about 10 s to 5 ns, provides a concise picture of the correlation of superparamagnetic relaxation with interparticle magnetic dipole interaction.
17. Measurements of field decay and snapback effect on Tevatron dipole and quadrupole magnets
SciTech Connect
Velev, G.V.; Ambrosio, G.; Annala, G.; Bauer, P.; Carcagno, R.; DiMarco, J.; Glass, H.; Hanft, R.; Kephart, R.; Lamm, M.; Martens, M.; Schlabach, P.; Sylvester, C.; Tartaglia, M.; Tompkins, J.; /Fermilab
2005-05-01
Since the beginning of 2002 an intensive measurement program has been performed at the Fermilab Magnet Test Facility (MTF) to understand dynamic effects in Tevatron magnets. Based on the results of this program a new correction algorithm was proposed to compensate for the decay of the sextupole field during the dwell at injection and for the subsequent field ''snapback'' during the first few seconds of the energy ramp. Beam studies showed that the new correction algorithm works better than the original one, and improves the Tevatron efficiency by at least 3%. The beam studies also indicated insufficient correction during the first 6s of the injection plateau where an unexpected discrepancy of 0.15 sextupole units of extra drift was observed. This paper reports on the most recent measurements of the Tevatron dipoles field at the beginning of the injection plateau. Results on the field decay and snapback in the Tevatron quadrupoles are also presented.
18. Gravitational electrical generator on magnetic fluid cushion
NASA Astrophysics Data System (ADS)
Călin Popa, Nicolae; Siblini, Ali; Jorat, Luc
1999-07-01
The paper describes the possibility to capture the energy of the vertical movement of the ocean waves, using a gravitational electrical generator on magnetic fluid cushion. This is constructed from a permanent magnet in a magnetic fluid shell, which, under the ocean waves action, is moving by translation inside a hermetically sealed tube.
19. Magnetism and Electricity Activity "Attracts" Student Interest
ERIC Educational Resources Information Center
Roman, Harry T.
2010-01-01
Electricity and magnetism are intimately linked, this relationship forming the basis of the modern electric utility system and the generation of bulk electrical energy. There is rich literature from which to teach students the basics, but nothing drives the point home like having them learn from firsthand experience--and that is what this
20. Magnetism and Electricity Activity "Attracts" Student Interest
ERIC Educational Resources Information Center
Roman, Harry T.
2010-01-01
Electricity and magnetism are intimately linked, this relationship forming the basis of the modern electric utility system and the generation of bulk electrical energy. There is rich literature from which to teach students the basics, but nothing drives the point home like having them learn from firsthand experience--and that is what this…
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https://link.springer.com/article/10.1007%2Fs00024-014-0840-9
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Pure and Applied Geophysics
, Volume 171, Issue 9, pp 2277–2287
# The Uncertainty of 2D Models Along Wide Angle Seismic Profiles
Open Access
Article
## Abstract
The estimation of uncertainty for any geophysical model is important for determining how reliable the model is. It is especially important for subjective trial and error modelling techniques like forward ray-tracing modelling of wide-angle seismic data when the final result is very dependent on the interpreter’s knowledge of the area and experience. In this kind of modelling, it is common to encounter over interpretation of the seismic data without checking the uncertainty of the result, especially in the deep parts that are not constrained with other a priori knowledge. In this paper, we propose a method of estimating the uncertainty of the final models based on a one dimensional method of small error propagation generalized for 2D profiles. With a simple approximation, we estimate the uncertainty for published interpretative models of selected profiles from seismic experiments in the Central Europe. We conclude that for typical wide angle seismic profiles we can reliably interpret four layered models of the Earth’s crust based on traveltimes fitting. We also show how the number of layers influence obtained uncertainties. Estimated uncertainties for both the velocity fields and the boundaries between layers are important for future tectonic and geodynamic interpretation of those profiles.
## Keywords
Wide-angle seismic earth’s crust modelling uncertainty
## 1 Introduction
In recent decades we significantly increased the amount of seismic data gathered to study the structure of the Earth’s crust and the upper mantle in pursuit of finding the most precise description of those structures. The raytracing technique is well known and often used for modelling of wide-angle seismic data. It is the most often used in the form of seismic tomography like FAST (Zelt and Barton 1998b) realised by fast eikonal solvers, but it is still used for trial and error forward modelling using SEIS83 code (Červený and Pšenčík 1984) and Rayinvr (Zelt and Smith 1992). SEIS83 was commonly employed in interpretation of a series of 2D profiles from large experiments in Central Europe, namely: POLONAISE’97 (Guterch et al. 1999), CELEBRATION 2000 (Guterch et al. 2003) and SUDETES 2003 (Grad et al. 2003b), resulting in many detailed interpretations having an important influence on local geodynamic interpretations. In interpretation of seismic models, it is important to present the results with an estimation of the uncertainty. This problem in difficult for the results of forward modelling and most often is addressed by showing the ray coverage. More detailed analysis presents some examples of the single parameter tests, for example, by Grad et al. (2008) or Janik et al. (2002) describing the uncertainty for velocities as ±0.1 km/s and depth of interfaces as ±2 km. This approach to error is too simple, especially in cases of complicated, multi layered models. It is obvious that uncertainty for both the velocity field and the depth of interfaces will be different for each layer. A more reliable estimation is needed to exclude the possibility of the over interpretation of the field data. A quantitative estimation of the uncertainties in the final model will help create the simplest possible model that can explain the observed data, and the tectonic interpretation of the result can proceed from this point.
For inversion problems with traveltimes picked for defined phases, we have many methods to assess the resolution of models. Starting from analysing ray paths, there are ray densities as described by Kissling (1988), to widely used checkerboard tests (Zelt 1998). To assess quantitative uncertainty of inversion parameters, we can use posterior covariance matrices proposed by Tarantola (1987). For this kind of problem we suggest using those methods. However, our method is targeted for interpreters using forward modelling that tries to fit traveltimes to observed wave fields instead of precisely matched phases picked to layers. For them, and for cases where we don’t have access to original data, we propose our robust approximation.
## 2 Method
The method of estimation of the uncertainties for 1D layered models we employ was explained by Majdański (2013). In short, it is based on a layer-stripping modelling strategy that employs both reflected and refracted arrivals to model each layer separately. Layers are modelled in order from the shallowest to deepest. Because rays have to propagate through the shallow structures to be reflected or refracted in deeper layers, the uncertainties for deeper layers have to include the uncertainties of the layers above them. To estimate these total uncertainties, we used a simplified ray propagation in 1D layered media approach that has an analytical description and employs error propagation theory according to the Eq. (1).
$$u_{c}^{2} = \mathop \sum \limits_{i = 1}^{N} \left( {\frac{\partial f}{{\partial x_{i} }}} \right)^{2} u^{2} \left( {x_{i} } \right).$$
(1)
We used simplified ray propagation as in Fig. 1. We use a 1D model of the crust with four layers with constant velocities. In the first layer we observe the direct wave with propagation time as in Eq. 2:
$$t_{1} = \frac{s}{{V_{1} }},$$
(2)
where t is propagation time, s is offset and V is P-wave velocity, then we can calculate the velocity and its uncertainty according to Eq. 1 as:
$$V_{1} = \frac{s}{{t_{1} }},\partial V_{1}^{2} = \left( {\frac{{\partial V_{1} }}{{\partial t_{1} }}} \right)^{2} \partial t_{1}^{2} = \left( {\frac{s}{{t_{1}^{2} }}} \right)^{2} \partial t_{1}^{2} .$$
(3)
During a synthetic test, we found that the uncertainty of position s is negligible comparing to the uncertainty in time. Propagation time for reflections in the first layer (t r1, Fig. 1) is:
$$t_{{{\text{r}}_{1} }} = \frac{{\sqrt {4h_{1}^{2} + s_{{{\text{r}}_{1} }}^{2} } }}{{V_{1} }},$$
(4)
where s r1 is the reflection arrival offset. Thickness of the first layer (h 1) and its uncertainty are expressed as in Eq. 5:
$$h_{1} = \frac{1}{2}\sqrt {V_{1}^{2} t_{{{\text{r}}_{1} }}^{2} - s_{{{\text{r}}_{1} }}^{2} } , \partial h_{1}^{2} = \left( {\frac{{\partial h_{1} }}{{\partial V_{1} }}} \right)^{2} \partial V_{1}^{2} + \left( {\frac{{\partial h_{1} }}{{\partial t_{{r_{1} }} }}} \right)^{2} \partial t_{{{\text{r}}_{1} }}^{2},$$
$$\partial h_{1}^{2} = \left( {\frac{{V_{1} t_{{{\text{r}}_{1} }}^{2} }}{{2\sqrt { V_{1}^{2} t_{{{\text{r}}_{1} }}^{2} {-}s^{2} r_{1} } }}} \right)^{2} \partial V_{1}^{2} + \left( {\frac{{V^{2}_{1} t_{{{\text{r}}_{1} }} }}{{2\sqrt { V_{1}^{2} t_{{{\text{r}}_{1} }}^{2} {-}s^{2} r_{1} } }}} \right)^{2} \partial t_{{{\text{r}}_{1} }}^{2} .$$
(5)
The refraction in deeper layers is expressed as head-waves that can be modelled as refraction propagating along interfaces. The traveltime of the head wave (t 2) is expressed as:
$$t_{2} = \frac{s}{{V_{2} }} + \frac{{2h_{1} }}{{V_{1} }}\sqrt {1 - \frac{{V_{1}^{2} }}{{V_{2}^{2} }}}.$$
(6)
If the velocities in adjacent layers are significantly different, we can simply Eq. 6 to:
$$t_{2} = \frac{{s_{2} }}{{V_{2} }} + \frac{{2h_{1} }}{{V_{1} }},$$
(7)
then we can express velocity and its uncertainty as:
$$V_{2} = \frac{{s_{2} V_{1} }}{{t_{2} V_{1} - 2h_{1} }},$$
$$\partial V_{2}^{2} = \left( {\frac{{\partial V_{2} }}{{\partial V_{1} }}} \right)^{2} \partial V_{1}^{2} + \left( {\frac{{\partial V_{2} }}{{\partial h_{1} }}} \right)^{2} \partial h_{1}^{2} + \left( {\frac{{\partial V_{2} }}{{\partial t_{2} }}} \right)^{2} \partial t_{2}^{2}.$$
(8)
The reflection in second and deeper layers (see Fig. 1) assumes vertical propagation in the upper layer, that is valid only if V 2 ≫ V 1. Full description is possible, but will significantly complicate underlying mathematics with no effect on the described problem. Therefore, the reflection is expressed as:
$$t_{{{\text{r}}_{2} }} = \frac{{2h_{1} }}{{V_{1} }} + \frac{{\sqrt {4h_{2}^{2} + s_{{{\text{r}}_{2} }}^{2} } }}{{V_{2} }}.$$
(9)
Then the thickness of the second layer (h 2) and its uncertainty is expressed as:
$$h_{2} = \frac{1}{2}\sqrt {\left( {\left( {t_{{{\text{r}}_{2} }} - \frac{{4h_{1} }}{{V_{1} }}} \right)V_{2} } \right)^{2} - s_{{{\text{r}}_{2} }}^{2} },$$
$$\partial h_{2}^{2} = \left( {\frac{{\partial h_{2} }}{{\partial V_{1} }}} \right)^{2} \partial V_{1}^{2} + \left( {\frac{{\partial h_{2} }}{{\partial V_{2} }}} \right)^{2} \partial V_{2}^{2} + \left( {\frac{{\partial h_{2} }}{{\partial h_{1} }}} \right)^{2} \partial h_{1}^{2} + \left( {\frac{{\partial h_{2} }}{{\partial t_{{r_{2} }} }}} \right)^{2} \partial t_{{{\text{r}}2}}^{2}.$$
(10)
By analogy, any additional layer will result in an additional partial derivative component in the equation for the uncertainty of velocities and another one in the equation describing the uncertainty of the thickness. From synthetic tests discussed by Majdański (2013) we can see that the uncertainties of both velocities and depths of boundaries depend on offset of observed arrivals. The uncertainty of velocities decreases with larger offsets, while the uncertainty of depth of a boundary increases with larger offsets. In addition, both effects are non-linear. To assure the smallest possible uncertainties, we need good quality data that allows observation of arrivals of reflected waves for large offsets, and observation of near-offset reflections, optimally near-vertical. All estimated uncertainties depend mostly on corresponding traveltime picking precisions $$\partial t$$ for each observed phase. Better picking precision will significantly reduce the uncertainties.
The application of this method to 2D profiles can be realised as a series of 1D estimations along the profile, assuming a local 1D geometry. To demonstrate the proposed method application the profile S02 from SUDETES 2003 experiment (Majdanski et al. 2006) was selected. The resulting model from forward trial and error modelling was converted to a dense grid of velocities (1 × 0.1 km) that can explain main tectonic structures with only a small loss of resolution (see Majdański et al. 2009 for details). Four boundaries were sufficient to model the data from the crustal point of view, and they formed a five layer model as shown in Fig. 2a. The first layer in the original model was composed from several layers derived from geological and borehole data interpretations. All this information is included in velocities in the first layer. The uncertainty of geological and borehole based data is much smaller than the traveltime inversion result. Thus, these layers are treated as a single layer with small uncertainty. At 1 km intervals along the profile we had a column of velocities and depths of interfaces. To this column of the data, we applied our 1D estimation procedure. Partial results along the profile were combined forming the 2D plot presented in Fig. 2b. In detail, the uncertainty in each layer depends on a local velocity distribution and a local depth of boundaries, but also on the offset of observed arrivals and travel time. Offsets of observed arrivals were different for each of nine shots along this profile, thus, for this analysis, the average values were used. For the first layer offset of observed arrivals ranged from 5 to 120 km. For the calculation of the uncertainties we used a 60 km offset with corresponding propagation time of 10.2 s and based on Eq. 3 resulted in an uncertainty of ∂V 1 = 0.029 km/s. The first boundary reflection was on average observed at 33 km with apropagation time of 7 s, and based on Eq. 5 resulted in an average uncertainty of ∂h 1 = 0.32 km.
For the second layer, the refraction was observed to an average offset of 180 km with propagation time of 31 s resulting according to Eq. 8 in an uncertainty of ∂V 2 = 0.025 km/s, which is lower than the one for the first layer. This is because the second layer is much thicker allowing propagation for larger distances so that the uncertainty of refraction arrivals decreases with offset. The reflection from the second layer was observed to an average offset of 110 km with propagation time of 18.8 s resulting according to Eq. 10 in a depth uncertainty ∂h 2 = 1.6 km. Refractions in deeper layers were observed at average offsets of 210 km and reflections at offsets 180 and 100 km for layers three and four. The uncertainty values are presented in Table 1 for easier comparison. For profile S02 describing a thin 32–35 km crust, we see a structure with limited variations. Still, we recognize larger uncertainties for the Moho discontinuity in the northern part of the profile resulting from significantly higher velocities in the lower crust.
Table 1
Estimated uncertainties presented as average values of separate layers of each discussed profile
Profile
S02
S01
P4
CEL05
CEL03
CEL09
S
N
S
N
$$\partial V_{1 }$$ (km/s)
0.029
0.029
0.029
0.029
0.03
0.03
0.03
0.03
$$\partial h_{1}$$ (km)
0.32
0.34
0.2
0.17
0.33
0.31
0.5
0.33
$$\partial V_{2}$$ (km/s)
0.025
0.032
0.02
0.022
0.027
0.021
0.05
0.025
$$\partial h_{2}$$ (km)
1.6
2.1
1.6
1.2
1.1
2.2
1.8
2.1
$$\partial V_{3}$$ (km/s)
0.15
0.21
0.11
0.1
0.19
0.17
0.18
$$\partial h_{3}$$ (km)
1.8
3.6
2.5
2.2
3.8
3.4
2.4
$$\partial V_{4}$$ (km/s)
0.25
0.45
0.17
0.24
0.47
0.38
0.36
$$\partial h_{4}$$ (km)
2.8
2.2
2.7
4.3
3.5
4.1
$$\partial V_{5}$$ (km/s)
0.45
0.33
0.64
0.27
0.63
0.64
0.61
This analysis is focused on estimating how picking precision, local number of layers, their thickness and velocities will influence the uncertainties. This way we can judge if additional layers to describe some local features are justified. We are not taking into account ray densities, number of shot points or local dipping structures. Full analysis is possible (e.g., if in the form of covariance matrices, Tarantola 1987), but require detailed ray-tracing and access to all the data, traveltime picks, etc. Often forward modelling is based on fitting arrivals to observed wave field without detailed traveltimes picking. Our method will also work for known models with no access to original data, because average traveltimes and offset of arrivals for each layer can be easily calculated.
## 3 Application of the Method
The first profile we discuss is S01 from the SUDETES 2003 experiment. As presented by Grad et al. (2008), a 30 km thick crust with some complicated bodies in the upper crust were derived This model was rebuilt using the previously described gridding technique and is presented in Fig. 3a. The first layer is composed by several layers based on geological and borehole data. The uncertainty for velocities and depth of boundaries are negligible compared to travel time inversion. Thus, this layer is a single layer with small uncertainties. The estimated uncertainties are presented in Fig. 3b and average values are shown in Table 1. For each layer estimated averages are: (in km/s) ∂V 1 = 0.029, ∂V 2 = 0.032, ∂V 3 = 0.21, ∂V 4 = 0.45, and for boundaries: (in km) ∂h 1 = 0.34, ∂h 2 = 2.1, ∂h 3 = 3.6. Compared to the single parameter estimations of Grad et al. (2008) as ±0.2 km/s for Pg, and ±2 km for Moho we see that it is not appropriate to use a single value for the whole velocity field, and that the Moho depth uncertainty should be significantly larger than for crustal layers.
The next profile we discuss is P4 from the POLONAISE’97 experiment. As presented by Grad et al. (2003a), a complicated transition structure across the Trans European Suture Zone (TESZ) from the East European Craton in the North (EEC) to Palaeozoic Platform was derived. The result was a complicated multi layers model [Fig. 8 in Grad et al. (2003a)], that is simplified in a series of the interpretation models [Fig. 17 in Grad et al. (2003a)]. Based on one of those models, profile P4 was rebuild, and it is presented in Fig. 4a and in Table 1. Complicated shallow structures in the TESZ part of the model are based on seismic reflection and borehole data with negligible uncertainties. Thus, they are described as a single layer. The crystalline crust of the model changes significantly around 300 km offset from thin 30 km crust to three layers, 50 km thick cratonic crust. The estimated uncertainties also changes significantly at that point as is presented in Fig. 4b. For the south part, we see values (in km/s): ∂V 1 = 0.029, ∂V 2 = 0.020, ∂V 4 = 0.17, ∂V 5 = 0.33 (no ∂V 3 in this part of the model). For the north part it is (in km/s): ∂V 1 = 0.029, ∂V 2 = 0.022, ∂V 3 = 0.11, ∂V 4 = 0.24, ∂V 5 = 0.64, which is roughly the same for shallow layers and significantly higher for the lower crust and the upper mantle. For boundaries it is (in km): south ∂h 1 = 0.2, ∂h 2 = 1.6, ∂h 4 = 2.2 (no ∂h 3 in this part), north ∂h 1 = 0.17, ∂h 2 = 1.2, ∂h 3 = 2.5, ∂h 4 = 2.7. The uncertainties depends on the number of layers, and they increase with layers. They also depend on the velocities in the overburden and are smaller for slow sediments areas. Also the crustal thickness affects our estimations, and the uncertainties, for both velocities and boundaries are larger for thicker crust.
Profile CEL05 is similar to P4 in that it crosses the TESZ and similar tectonic units but is located to the south and crossed the Carpathian Mountains. The profile is very long being 1,400 km. The model of [Grad et al. (2006), Fig. 19] was converted using gridding technique as in Fig. 5a and in Table 1. As before, the first few kilometres in the first layer are based on geological and borehole data and have negligible uncertainty, and are, thus, described as a single layer. Again, in the crystalline part of the model we see a significant change in uncertainties (Fig. 5b) around 500 km offset. Values obtained from the estimation are (in km/s): south ∂V 1 = 0.03, ∂V 2 = 0.027, ∂V 3 = 0.1, ∂V 5 = 0.27, north ∂V 1 = 0.03, ∂V 2 = 0.021, ∂V 3 = 0.19, ∂V 4 = 0.47, ∂V 5 = 0.63. For boundaries (in km): south ∂h 1 = 0.33, ∂h 2 = 1.1, ∂h 3 = 2.2, north ∂h 1 = 0.31, ∂h 2 = 2.2, ∂h 3 = 3.8, ∂h 4 = 4.3. The Moho uncertainty is twice as large in the north as to the south. This is an effect of high velocity in the lower crust that has a large uncertainty.
Next discussed profile is a combination of the TTZ and CEL03, as presented by Janik et al. (2005). It describes a complicated multi-layered structure along the TESZ. Their model contains in the crystalline crust some localised high velocity bodies and intra crust reflectors (Fig. 12 in Janik et al. 2005) and was gridded as a four layer crust model (Fig. 6a; Table 1). Again, the sediments are represented in complicated structures in the upper first few kilometres that were derived from geological and borehole data and were represented as a single layer with negligible uncertainty. The average uncertainties (Fig. 6b) are: for velocities (in km/s) ∂V 1 = 0.03, ∂V 2 = 0.05, ∂V 3 = 0.17, ∂V 4 = 0.38, ∂V 5 = 0.64, and for boundaries (in km) ∂h 1 = 0.5, ∂h 2 = 1.8, ∂h 3 = 3.4, ∂h 4 = 3.5. For this model there are no significant differences with offset, because the sedimentary layer is observed for the whole model and no significant lateral velocity variation is observed. The uncertainties postulated by Janik et al. (2005) as ±0.1 km/s for velocities in the lower crust and ±1 km for Moho boundary should be significantly larger.
The final discussed model CEL09 from CELEBRATION 2000 experiment was analysed by Hrubcová et al. (2005). It is located in the Bohemian Massif and has a triple crustal block structure. The gridded model is presented in Fig. 7 with estimated uncertainties. The uncertainties averages are: for velocities (in km/s) ∂V 1 = 0.03, ∂V 2 = 0.025, ∂V 3 = 0.18, ∂V 4 = 0.36, ∂V 5 = 0.61, and for boundaries (in km) ∂h 1 = 0.33, ∂h 2 = 2.1, ∂h 3 = 2.4, ∂h 4 = 4.1. The middle part of the profile with only two crustal layers has much smaller uncertainties comparing to edges of the profile with separate lower crust layers.
## 4 Conclusions
We propose a technique for estimation of how picking precision of traveltimes affects the uncertainty of modelled layers. With this simple approximation, we can estimate the uncertainties for velocity and depth of boundaries for a given model, and show how the uncertainty will increase with each added layer. As the method is based on 1D approximation, it will be more accurate for layers not deviating much from flat ones. For strongly dipping structures, the estimates may be less accurate, but the effect of the accumulation of uncertainties by error propagation to consecutive layers will still be viable.
The estimated uncertainties for the profiles analysed for deep layers are larger than suggested by the published studies using ray-tracing modelling. For velocities in shallow layers, especially modelled using Pg arrivals observed for long distances, the estimated uncertainties are much smaller (about 0.03 km/s). The uncertainty of velocities rapidly increases with added layers, because of a cumulative effect of uncertainty for boundaries based on wide-angle data. In general, for typical picking precisions ∂t = 0.1 s, wide-angle reflections provide uncertainties >2.5 km for depth of the reflecting boundary for the 3rd and any additional layers in a model. This uncertainty will be significantly smaller for analysis based on near-vertical reflections (see Majdański 2013 for details). For interpretation of the results of ray-tracing modelling, it is important to use published tectonic interpretations and not the ray-tracing models themselves. As a general result of the analysis presented, we claim that for a typical crustal scale wide-angle seismic data (shot spacing about 30 km, receiver spacing about 3 km), with good quality data (high S/N ratio, clear long offset arrivals, picking precision about 0.1 s) crustal models containing up to 4–5 layers based on traveltime modelling can be obtained. Any number of additional layers derived on a priori geological knowledge or boreholes data with negligible uncertainty can be added without the impact on the uncertainty of deeper layers. The main limitation is time picking precision, which can vary substantially depending on depth and offset. Using a larger number of layers modelled and using a layer stripping approach will lead to unreliable models in the sense of uncertainty. More layers in models are possible if near vertical reflection data were used to model boundaries.
Those seeking geological interpretations would like to have models as shown in Fig. 8a, b, rather than the smooth results from tomography as presented in Fig. 8d. However, when looking at the corresponding uncertainties in Fig. 8e–g, we come to the conclusion that some trade-off between number of parameters and their uncertainties is needed. We propose that results shown in Fig. 8c with its uncertainties shown in Fig. 8g becomes a reasonable choice. We still can recognize important details, while the uncertainties are reasonably small. As always, achieving the minimum-structure model as in Occam’s razor principle should be our goal, but additional knowledge about the uncertainties is very important and should be a factor in the final interpretative result.
## Notes
### Acknowledgments
This work was funded by the National Science Centre (NCN) Grant Number DEC-2012/05/B/ST10/00052. We would like to thank two anonymous reviewers for many suggestions that significantly improved this paper.
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http://physics.stackexchange.com/questions/94327/do-photons-feel-gravity-of-approaching-objects-only
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# Do photons feel gravity of approaching objects only?
I have read that photons while travelling near massive objects such as the sun experience gravitational pull which is why we see some stars at different positions than they are when seen towards the sun.
Now if photons felt gravity of objects they approach, speed of propagation of gravitational field can be both lesser than or equal to speed of light, but if photons that are receding from objects also feel it's gravity than certainly speed of propagation of gravity would be more than speed of light !
So the question is do photons feel gravity of object they move away from ? If they do is my assertion correct ?
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According to my basic knowledge, photon has zero rest mass. Newton's gravitational law involves rest mass, I hope. So, I think photon shouldn't feel any gravitational force. However, there might be solution w.r.t rlativistic mass as you are saying (in first two lines) they will feel force. – Godparticle Jan 19 at 10:10
@VINAY : Have you read somewhere that newton's law involves rest mass ? Where ? – Rijul Gupta Jan 19 at 10:13
possible duplicate of The speed of gravity? – Wojciech Morawiec Jan 25 at 23:34
It's better to think of the deflection of the photon as an effect of its travel through curved spacetime. You can generally choose to analyze the problem in the rest frame of the massive object. In that case spacetime is curved in all directions around the object, and so the photon's path is deflected both as it approaches and as it recedes.
If you want to think of the gravitational field as an effect of gravitons travelling at $c$, you have to remember that the massive object doesn't come into existence as the photon passes it: the photon can feel the gravitational force "emitted" by the mass in the past. (I feel a little squicky talking about gravitational attraction as something that is "emitted.")
Now, if the massive object were to begin to oscillate after the photon had passed, the gravitational waves emitted by the oscillating object wouldn't be able to catch up with the photon. But that's a more subtle situation than the one in your question.
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https://ftp.aimsciences.org/article/doi/10.3934/cpaa.2014.13.1799
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# American Institute of Mathematical Sciences
September 2014, 13(5): 1799-1814. doi: 10.3934/cpaa.2014.13.1799
## On the free boundary for quenching type parabolic problems via local energy methods
Received October 2013 Revised January 2014 Published June 2014
We extend some previous local energy method to the study the free boundary generated by the solutions of quenching type parabolic problems involving a negative power of the unknown in the equation.
Citation: Jesús Ildefonso Díaz. On the free boundary for quenching type parabolic problems via local energy methods. Communications on Pure and Applied Analysis, 2014, 13 (5) : 1799-1814. doi: 10.3934/cpaa.2014.13.1799
##### References:
[1] S. N. Antontsev, J. I. Díaz and S. Shmarev, The support shrinking properties for solutions of quasilinear parabolic equations with strong absorption terms, Annales de la Faculté des Sciences de Toulouse, IV (1995), 5-30. [2] S. N. Antontsev, J. I. Diaz and S. I. Shmarev, Energy Methods for Free Boundary Problems: Applications to Nonlinear PDEs and Fluid Mechanics, Birkhäuser, Boston, 2001. doi: 10.1007/978-1-4612-0091-8. [3] F. Bernis, Finite speed of propagation and asymptotic rates for some nonlinear higher order parabolic equations with absorption, Proceedings of the Royal Society of Edinburgh: Section A Mathematics, 104 (1986), 1-19. doi: 10.1017/S030821050001903X. [4] H. Brezis, Monotonicity methods in Hilbert spaces and some applications to nonlinear partial differential equations, in Contributions to Nonlinear Functional Analysis (ed. E. Zarantonello), Academic Press, New York, 1971, 101-156. [5] A. N. Dao and J. I. Díaz, The existence of renormalized solutions with right-hand side data integrable with respect to the distance to the boundary, and application of the energy method for free boundary problems to some solutions out of the energy space,, to appear., (). [6] A. N. Dao, J. I. Díaz and P. Sauvy, Quenching phenomenon of singular parabolic problems with $L^{1}$ initial data,, to appear., (). [7] J. Dávila and M. Montenegro, Existence and asymptotic behavior for a singular parabolic equation, Transactions of the AMS, 357 (2004), 1801-1828. doi: 10.1090/S0002-9947-04-03811-5. [8] J. I. Díaz, Nonlinear Partial Differential Equations and Free Boundaries, Research Notes in Mathematics, 106, Pitman, London 1985. [9] J. I. Díaz, Estimates on the location of the free boundary for the obstacle and Stefan problems by means of some energy methods, Georgian Mathematical Journal, 15 (2008), 455-484. [10] J. I. Díaz and J. Hernández, Positive and free boundary solutions to some singular nonlinear elliptic problems with absorption: an overview and open problems,, to appear in \emph{Electronic J. Differential Equations}., (). [11] J. I. Díaz, J. Hernández and F. J. Mancebo, Branches of positive and free boundary solutions for some singular quasilinear elliptic problems, J. Math. Anal. Appl., 352 (2009) 449-474. doi: 10.1016/j.jmaa.2008.07.073. [12] J. I. Díaz, J. Hernández and J. M. Rakotoson, On very weak positive solutions to some semilinear elliptic problems with simultaneous singular nonlinear and spatial dependence terms, Milan J. Maths, 79 (2011), 233-245. doi: 10.1007/s00032-011-0151-x. [13] J. I. Díaz, J. Hernández and J. M. Rakotoson, On very weak positive solutions to some singular second order semilinear elliptic problems,, in preparation., (). [14] J. I. Díaz, J. M. Morel and L. Oswald, An elliptic equation with singular nonlinearity, Comm. in Partial Differential Equations, 12 (1987), 1333-1344. doi: 10.1080/03605308708820531. [15] J. I. Díaz and L. Veron, Local vanishing properties of solutions of elliptic and parabolic quasilinear equations, Trans. of Am. Math. Soc., 290 (1985), 787-814. doi: 10.2307/2000315. [16] J. Giacomoni, P. Sauvy and S. Shmarev, Complete quenching for a quasilinear parabolic equation, J. Math. Anal. Appl., 410 (2014), 607-624. doi: 10.1016/j.jmaa.2013.08.051. [17] J. Hernández and F. Mancebo, Singular elliptic and parabolic equations, in Handbook of Differential equations (ed. M. Chipot and P. Quittner), vol. 3. Elsevier, 2006, 317-400. [18] H. Kawarada, On solutions of initial-boundary problem for $u_t=u_{xx}+1/(1-u)$,, \emph{Publ. Res. Inst. Math. Sci}., 10 (): 729. [19] B. Kawohl, Remarks on Quenching, Doc. Math., J. DMV, 1 (1996) 199-208. [20] B. Kawohl and R. Kersner, On degenerate diffusion with very strong absorption, Mathematical Methods in the Applied Sciences, 15 (1992), 469-477. doi: 10.1002/mma.1670150703. [21] O. Ladyzhenskaya, V. Solonnikov and N. Ural'tseva, Linear and Quasilinear Equations of Parabolic Type, Nauka, Moscow, 1967. English translation: American Mathema-tical Society, Providence, Rhode Island, 1968. [22] H. A. Levine, Quenching and beyond: a survey of recent results, in Nonlinear mathematical problems in industry, II (Iwaki, 1992), vol. 2 of GAKUTO Internat. Ser. Math. Sci. Appl., Gakkōtosho, Tokyo, 1993, 501-512. [23] J.-L. Lions, Quelques méthodes de résolution des problèmes aux limites non linéaires, Dunod, Paris, 1969. [24] L. Nirenberg, An extended interpolation inequality, Ann. Scuola Norm. Sup. Pisa, 3 (1966), 733-737. [25] D. Phillips, Existence of solutions of quenching problems, Appl. Anal., 24 (1987), 253-264. doi: 10.1080/00036818708839668. [26] J. M. Rakotoson, Regularity of a very weak solution for parabolic equations and applications, Advances in Differential Equations, 16 (2011), 867-894. [27] M. I. Vishik, Systèmes d'équations aux dérivé es partielles fortement elliptiques quasi-linéaires sous forme divergente, Troudi Mosk. Mat. Obv., 12 (1963), 125-184. [28] M. Winkler, Instantaneous shrinking of the support in degenerate parabolic equations with strong absorption, Adv. Differential Equations, 9 (2004), 625-643. [29] M. Winkler, A strongly degenerate diffusion equation with strong absorption, Math. Nachrichten, 277 (2004), 83-101. doi: 10.1002/mana.200310221. [30] M. Winkler, Nonuniqueness in the quenching problem, Math. Ann., 339 (2007), 559-597. doi: 10.1007/s00208-007-0123-1.
show all references
##### References:
[1] S. N. Antontsev, J. I. Díaz and S. Shmarev, The support shrinking properties for solutions of quasilinear parabolic equations with strong absorption terms, Annales de la Faculté des Sciences de Toulouse, IV (1995), 5-30. [2] S. N. Antontsev, J. I. Diaz and S. I. Shmarev, Energy Methods for Free Boundary Problems: Applications to Nonlinear PDEs and Fluid Mechanics, Birkhäuser, Boston, 2001. doi: 10.1007/978-1-4612-0091-8. [3] F. Bernis, Finite speed of propagation and asymptotic rates for some nonlinear higher order parabolic equations with absorption, Proceedings of the Royal Society of Edinburgh: Section A Mathematics, 104 (1986), 1-19. doi: 10.1017/S030821050001903X. [4] H. Brezis, Monotonicity methods in Hilbert spaces and some applications to nonlinear partial differential equations, in Contributions to Nonlinear Functional Analysis (ed. E. Zarantonello), Academic Press, New York, 1971, 101-156. [5] A. N. Dao and J. I. Díaz, The existence of renormalized solutions with right-hand side data integrable with respect to the distance to the boundary, and application of the energy method for free boundary problems to some solutions out of the energy space,, to appear., (). [6] A. N. Dao, J. I. Díaz and P. Sauvy, Quenching phenomenon of singular parabolic problems with $L^{1}$ initial data,, to appear., (). [7] J. Dávila and M. Montenegro, Existence and asymptotic behavior for a singular parabolic equation, Transactions of the AMS, 357 (2004), 1801-1828. doi: 10.1090/S0002-9947-04-03811-5. [8] J. I. Díaz, Nonlinear Partial Differential Equations and Free Boundaries, Research Notes in Mathematics, 106, Pitman, London 1985. [9] J. I. Díaz, Estimates on the location of the free boundary for the obstacle and Stefan problems by means of some energy methods, Georgian Mathematical Journal, 15 (2008), 455-484. [10] J. I. Díaz and J. Hernández, Positive and free boundary solutions to some singular nonlinear elliptic problems with absorption: an overview and open problems,, to appear in \emph{Electronic J. Differential Equations}., (). [11] J. I. Díaz, J. Hernández and F. J. Mancebo, Branches of positive and free boundary solutions for some singular quasilinear elliptic problems, J. Math. Anal. Appl., 352 (2009) 449-474. doi: 10.1016/j.jmaa.2008.07.073. [12] J. I. Díaz, J. Hernández and J. M. Rakotoson, On very weak positive solutions to some semilinear elliptic problems with simultaneous singular nonlinear and spatial dependence terms, Milan J. Maths, 79 (2011), 233-245. doi: 10.1007/s00032-011-0151-x. [13] J. I. Díaz, J. Hernández and J. M. Rakotoson, On very weak positive solutions to some singular second order semilinear elliptic problems,, in preparation., (). [14] J. I. Díaz, J. M. Morel and L. Oswald, An elliptic equation with singular nonlinearity, Comm. in Partial Differential Equations, 12 (1987), 1333-1344. doi: 10.1080/03605308708820531. [15] J. I. Díaz and L. Veron, Local vanishing properties of solutions of elliptic and parabolic quasilinear equations, Trans. of Am. Math. Soc., 290 (1985), 787-814. doi: 10.2307/2000315. [16] J. Giacomoni, P. Sauvy and S. Shmarev, Complete quenching for a quasilinear parabolic equation, J. Math. Anal. Appl., 410 (2014), 607-624. doi: 10.1016/j.jmaa.2013.08.051. [17] J. Hernández and F. Mancebo, Singular elliptic and parabolic equations, in Handbook of Differential equations (ed. M. Chipot and P. Quittner), vol. 3. Elsevier, 2006, 317-400. [18] H. Kawarada, On solutions of initial-boundary problem for $u_t=u_{xx}+1/(1-u)$,, \emph{Publ. Res. Inst. Math. Sci}., 10 (): 729. [19] B. Kawohl, Remarks on Quenching, Doc. Math., J. DMV, 1 (1996) 199-208. [20] B. Kawohl and R. 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https://math.stackexchange.com/questions/2288774/why-is-the-roll-of-a-die-considered-random/2291979
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# Why is the roll of a die considered random?
I've been reading articles on pseudo-randomness in computing when generating a random value. They all state that the generated numbers are pseudo-random because we know all the factors that influence the outcome, and that the roll of a die is considered truly random. But I'm wondering why. Don't we know all the physical forces that influence the die when it's being rolled? Or is there too many of them?
• Can you accurately predict every single nerve pulse running to the muscles controlling the hand that rolls the die? – celtschk May 20 '17 at 9:45
• "It is shown that for the realistic values of the initial energy the probabilities of the die landing on the face which is the lowest one at the beginning is larger than the probabilities of landing on any other face. [...] In real experiment, the predictability is possible only for very small \epsilon, i.e., an accuracy which in practice is extremely difficult to implement[...]" -- The three-dimensional dynamics of the die throw, Kapitaniak, Strzalko, Grabski, Kapitaniak. – Jeffrey Bosboom May 20 '17 at 22:08
• To go with all the great answers here, I'd like to point out your own phrasing, "... the roll of a die is considered truly random." Whether or not there is anything truly described as random in this universe is actually a philosophy question. However, as many have pointed out, the die is "close enough" to random to earn a particular level of fame. – Cort Ammon May 20 '17 at 22:19
• So many awful answers upvoted to the top. Guys, not every instance of the "random"ness you see in your daily life is an example of chaos or quantum theory. Use your common sense, people. – Mehrdad May 20 '17 at 23:03
• No @Mehrdad , I don't get your point, and I don't think yours is a productive attitude. The millisec digit of a chronometer stopped without looking is randomness without chaos. To me, the bounces of a die are chaotic. – lesath82 May 21 '17 at 7:42
A die roll is only considered random if the external factors are not controlled.
Practiced dice cheats can roll numbers they want to roll. So talk about nerves and blood vessels and quantum effects are just wrong. These cheats control the meaningful factors such that they influence the outcome of the roll, predictably. Even if someone only increases their chance of rolling a certain number by a few percentage points, that's huge in gambling terms.
That's why there are rules on how the dice must be rolled at casinos, and inventions such as the dice tower:
.
• That tower doesn't seem as chaotic as the Dice-o-matic – Nick T May 21 '17 at 4:57
• @NickT One of those devices might be more portable than the other... – Tony Ennis May 21 '17 at 11:56
• Even if the external factors are largely controlled, it is still random. This seems to be missing from many answers here: random does not necessarily mean uniform random, and a biased die throw is still random. For PRNG's however all external factors are controlled, and there is no entropy at all. – TMM May 22 '17 at 18:41
• The die that came through the tower are obviously NOT random. All three are powers of a prime! AND are also Fibonacci numbers! – richard1941 May 23 '17 at 18:28
• Also, the sum of the three die is a power of a prime AND a Fibonacci number! The tower merely requires greater skill from the cheater; it does not stop her from cheating. – richard1941 May 23 '17 at 18:36
This has to do with chaos theory: the tiniest variation of the initial conditions will cause an enormously different output. For a physical system like a die toss:
• even from a classical point of view, it is very unlikely that you can know the very exact initial conditions of the throw. And of the environment: the "floor" distance and surface characteristics (think of the abrupt effect of each bounce, that will be very different depending on the most infinitesimal variation of the impact parameters), the air conditions (thermodynamic and kinematic)...!
• this becomes actually impossible if you include the uncertainty principle (that prevents you from knowing the exact value of certain pairs of variables at the same time, e.g. position and momentum, but see below);
• it would be impossible from a practical point of view to propagate these initial conditions without introducing round-off errors, that due to the chaotic nature of the problem would make the result completely unreliable;
• even if you could perform exact calculations, there is still the quantum indeterminacy (again, see below) that affects the development of the status of the die: at each bounce, even when air molecules brake the die rotation, it is impossible even theoretically to predict what will happen in the next instant with absolute certainty.
As pointed out in many comments and with many downvotes, the contributions to the randomness of the roll from quantum effects are insignificant from any practical point of view. Nevertheless I do want to mention them since they provide a theoretical watertight border against a deterministic idea of the phenomenon.
Taking care of another possible correct objection, I have to underline that my answer holds for a fair throw. If you think of a die "tossed" from, say, $1\,\mathrm{mm}$ above a horizontal flat floor, with negligible initial velocity and a face parallel to the ground, it is obvious that you can predict the outcome with practical certainty. Moving progressively away from this limit situation, you have many halfway toss styles that can influence the probability distribution of the outcomes, if only by a few percent. I'm referring to the opposite limit, when the system can be considered ergodic. When I heard this term applied to the die, maybe not $100\%$ properly, it was with the meaning that the system "scans" over time all the possible outcomes many many times, with equal probability and with no recognizable pattern. Add the fact that a fair throw starts with a random grip of the die, and you really have equal chances for all the outcomes.
• Quantum effects don't really come into play here. – Matt Samuel May 20 '17 at 12:42
• You can say they should be negligible, since the average of an enormous amount of probabilistic microscopic effects usually leads to a predictable macroscopic outcome. But it is never going to be exact in a mathematical sense – lesath82 May 20 '17 at 12:54
• @bleh They're too small. – Matt Samuel May 20 '17 at 12:54
• @Zelphir Technically it's not equal to $0$, but with the exact same initial forces the outcome will be the same to many many decimal places. Minuscule doesn't even begin to describe the influence of quantum effects on something that big. – Matt Samuel May 20 '17 at 14:36
• This answer needs a tl;dr saying that we call it random because with current technology it is not humanly possible to predict the outcome of any given roll even if we know the outcome of all past rolls. – Readin May 20 '17 at 19:43
The roll of a die is modelled as being random.
The purpose of a mathematical model is to help us to understand some feature of the world.
A real die falling onto a surface is a mechanical system. It can be modelled by a deterministic mechanical model, which could be used to generate pseudorandom numbers. However, this is not usually a particularly useful model. Instead we can use a uniform discrete distribution as a model for the die. This is a much better model. It simplifies the mechanical system, and allows you to gain insight into the world. It allows you to consider the expected value and variance of the die roll (these concepts would be hidden by the detail of the mechanical model).
In mathematical questions phrases like "Yusuf rolls a fair die..." are part of the code: It means "There is a random variable with a discrete uniform distribution on {1...6}. The question is asking you to form a mathematical model. A more sophisticated model takes into account the slight biases due to the mass of the die not being centred, or the sides not being identical.
This is what is meant by a die being random: It is an object that is usefully modelled by a random variable.
• Note that "randomness" does not require a discrete uniform distribution. Yusuf and his die could be random, but biased. So, how do you test Yusuf and his die for randomness, if they might be biased but still random? – richard1941 May 29 '17 at 16:45
I feel the existing answers all concentrate on the dice and would like to offer another perspective, concerned with the generator:
The "pseudo" in "pseudo random generator" means that the next value is completely determined. There is no surprise at all, no matter what you do. The only "surprise factor" arises if you do not happen to know the internal state of the generator. But it is trivially easy to get the internal state (just read out the RAM), and it is there.
Also, if you restore a known internal state, you can repeat the series of "random" values you got before. This is actually, where PRNGs are used, often a welcome feature - for example, you can generate a lot of, well, pseudorandom data from a very small seed value. So to communicate whatever you generated, you only need to transfer the seed, not all values. Or you can test something which needs seemingly random input in a repeatable way (for debugging, demonstration etc.).
For dice, or many other physical processes, the problem is not so much that we are too stupid to read out the state, but that there actually is no deterministic process underlying whatever we are using to generate the next random value. It is not so much about us not being able to figure it out ("read the RAM") but that there "is no RAM". For dice, the previous roll of the dice has no relation whatsoever to the next roll. Sure, we might, in ideal conditions and with stunning advances in measuring apparatuses, somehow try to predict the current roll while it is happening. But even if we'd manage to do that (quantum effects, Heisenberg, chaotic effects ignored), this roll would have no relation whatsoever with the next roll. Hence we call it truly (independently) random.
If you are more interested, a nice read is "The Art of Computer Programming" by Knuth. He spends a lot of time on PRNGs, including how to measure how "random" a random generator actually is.
• My pennyworth: a "random" sequence is often confused with "equal distribution". If that were so, gamblers could look at the history and say "a 6 is due" but as you say, that is a false hope. People often evaluate a PRNG by its statistical results, because practically they do want a "random but uniform distribution", and not "random" which can be anything. Also, I am suprised nobody has yet mentioned the butterfly effect. – Weather Vane May 20 '17 at 19:28
• Much better description of psudorandom vs really random than the other answers – Sir Adelaide May 22 '17 at 1:43
• @WeatherVane The "random" distribution of an ideal six-sided die is an equal distribution. The gambler's fallacy is the idea that the "equal distribution" can ever tell us that "a 6 is due." – David K May 22 '17 at 13:46
• To expand on the point about the pseudorandom seed, you can use this feature to debug a "random" algorithm implemented in a computer. With a truly random generator you would not be able to reliably reproduce the circumstances that led to observing the bug. – David K May 22 '17 at 13:50
• @WeatherVane In this context "equal distribution" means what the statistician says it means. If you try to use it with a different meaning in a mathematical discussion, you will cause a lot of confusion and pointless arguments. You're in the middle of such a pointless argument right now, in fact. – David K May 22 '17 at 17:27
Even without invoking Quantum Theory, some systems are chaotic. In principle, they can be predicted but this requires impossibly perfect measurements of the initial state. Quantum theory prohibits these perfect measurements but such precision would be required that even without quantum mechanics, sufficiently perfect measurements would not be possible.
One nice example is a toy which is a consists of a pendulum which contains a magnet over a base with two magnets; the magnets are aligned to attract the pendulum. Place the base magnets slightly either side of the rest point of the pendulum. Move the pendulum off centre and release it. It will come to rest over one of the magnets but which? There will be areas around each base magnet in which the pendulum will predictably stop over that magnet. However, outside those areas, the behaviour is very complex. Here is one of the first hits that I found in a search, I expect that there are better ones: A pendulum and two magnets - an example of a chaotic system.
A purer mathematical example is the Mandelbrot set. In principle it is utterly predictable. Any point is either in the set or not. However, in some areas, this cannot be determined in finite number of steps. Mandelbrot set at Wikipedia
Another example is the solar system. Assume that Newton was right and ignore everything except the Sun and major planets (include Pluto if you wish). With a perfect measurement of the initial state and perfect calculations, we could predict its future indefinitely into the future. However, the tiniest error could render the results seriously wrong later on.
• I think the Mandelbrot set is a bit of a "bad" example. Just like PRNGs it "looks" random but is completely deterministic. Saying that it is "too complicated to predict" is not really a good measure - if I just give you the output of a PRNG you may also have a hard time predicting the next output, which does not mean it is truly random. – TMM May 20 '17 at 9:10
• @TMM Actually, that was the point of the example. Even in the predictable world of pure mathematics, it is only predictable in an idealistic Platonic sense. Which is more surprising: that the Newtonian Solar System is predictable in principle but not in practice or that the Mandelbrot isn't practically predictable either? My message is that, in the real world, we have to live with unpredictability. You could say that randomness is just ignorance or the inability to calculate well enough. My examples are intended to show that randomness isn't going away. – badjohn May 20 '17 at 9:24
• The Lorenz example is one of the simpler systems that exhibit exquisite sensitivity to initial conditions. – J. M. is a poor mathematician May 20 '17 at 14:35
• @badjohn I understand that some randomness concepts are debatable, but it might not be wise to stray from standard definitions for these questions. I could also argue that the program "print 1" is a true RNG, where the randomness comes from the random physical behavior of the processor, where say once in a blue moon the processor outputs 0 due to some internal screw-up. After all, there are no requirements on RNGs that the output is uniform; any non-zero entropy generator qualifies. (But when explaining PRNG vs RNG I would not use that as an example.) – TMM May 20 '17 at 22:30
• @TMM My only point here is that to get unpredictable behaviour, you don't have to leave mathematics. Is there a standard definition randomness? Possibly in Computer Science but this is a Mathematics group. For example, Wolfram MathWorld is fairly vaguely on the subject. mathworld.wolfram.com/Random.html – badjohn May 21 '17 at 8:26
Don't we know all the physical forces that influence the die when it's being rolled?
Yes. But, when throwing a die in a normal way, we aren't able to control the initial conditions (i.e. the position where you throw the die, and the applied force) and other conditions which might affect the throw (e.g. air currents).
Even when you just 'drop' a die from a certain height, you'll see the outcomes are random. That is, until you reduce the height to a fraction of the size of the die; then the forces are small enough to be able to predict the outcome of the 'throw'.
• "you'll see the outcomes are random" - How do you "see" that an experiment produces truly random rather than pseudo-random results? – TMM May 20 '17 at 8:46
Think of a Galton board.
Even though all balls are dropped the same way, the outcomes of the collisions are completely unpredictable.
The device will be influenced by a person caughing in the next room. The same goes with dice.
• love this one analogy, for me the clearest so far – lesath82 May 26 '17 at 12:24
We argue using simple models that all successful practical uses of probabilities originate in quantum fluctuations in the microscopic physical world around us, often propagated to macroscopic scales. Thus we claim there is no physically verified fully classical theory of probability. We comment on the general implications of this view, and specifically question the application of classical probability theory to cosmology in cases where key questions are known to have no quantum answer. We argue that the ideas developed here may offer a way out of the notorious measure problems of eternal inflation.
So, whenever something is truly random, the probabilistic aspects of it will always derive from quantum mechanical processes. In the article it's explained how quantum processes in the brain propagate via our nerves to our hands when we throw coins or throw dice. And this is true even if you consider betting on the value of the digits of $\pi$. The probability that the $123543745345385$th binary digit of $\pi$ is 0 seems to be a purely classical probability, but in the article it's pointed out that even this probability has a purely quantum mechanical origin.
We assume randomness when identical inputs to a system give rise to different outputs. For a die roll, we are not able to consistently describe the changes to the system from roll to roll, for as you've supposed there are too many factors (and see Chaos Theory). So while a phenomenon may in principle be best modelled deterministically, it's often more practical and "good enough" to use a random model instead.
There are no such things as "truly random" and "pseudorandom", at least in science.
An event is random if you do not have enough information to determine its outcome. Randomness depends on your state of information. This includes that an event may be random for you, but not somebody else (who has more knowledge).
For an outsider, who cannot see the internal state of a computer, the sequence generated by that computer may be random because he/she has not enough information to determine the next number. For the computer admin, the sequence is not random.
Some events (e.g. in quantum states) may be "truly random" in the sense that it is impossible to gather enough information to predict them. But this is a purely philosophical question and nobody can say whether some clever physicist will be able to predict quantum states in the future.
• Einstein was a defender of the theory of hidden variables, i.e. the idea that there is anyway some determinism to which we don't have access. But the experiment of Alan Aspect seems to have refuted it. – Yves Daoust Jul 18 '18 at 21:21
• AFAIK, Alain Aspect investigated local hidden variables. I do not see how hidden variables in general could be ruled out. – J. Fabian Meier Jul 19 '18 at 6:25
The existence of true randomness is a philosophical question. However, many completely deterministic processes approximate the statistical properties of randomness. This is how we develop and test pseudo-random number generators, which are completely deterministic processes that nonetheless are statistically indistinguishable from a truly random process.
Therefore, one good operational definition of a random process is that it passes the same tests that pseudo-random number generators must pass (suitably adjusted for whatever non-uniformity we are assuming about the process).
So, we consider a die roll to be statistically random insofar as it satisfies the requirements we would place on an equivalent pseudorandom number generator.
As an example, one such requirement is the absence of any statistically significant autocorrelation between successive rolls (up to some large number of lags). Technically, all pseudorandom number generators will fail this test for a sufficiently large lag (very, very large), where the autocorrelation will spike to 1.0.
However, for smaller lags, it will behave statistically like it came from a process that can generate any value in its range for any given trial.
• Tell me more.... I am interested in how to test for randomness, when the underlying distribution is unknown. What about "spurious correlations"? – richard1941 May 29 '17 at 17:00
If we know the algorithm of a pseudo-random number generator, and we know its current internal state, then we can predict with certainty the next number.
But with a die roll, although we might be able to predict with some level of accuracy what the number might be, it depends on how much we know about factors such as:
1. the starting position and orientation of the die
2. how it is picked up and thrown
3. the motion and density of the air it passes through
4. the surface it lands on, particularly at the points where it will probably land/bounce
If we collude with the roller and have them "roll" it by placing it on the surface with a given number facing upwards - effectively controlling point 2 above - then we can even predict, with great surety, what the outcome will be.
Therefore we must make some additional assumptions about our level of knowledge/control in order to consider a die roll to be random.
Informally, I'd say that we would tend to assume:
1. only vague knowledge of a die's position and orientation (maybe just which number is facing up)
2. no knowledge of how it will be picked up and thrown
At this point, I would expect any outcome to be possible (even if the air and surface were the same each time). So with just those two assumptions, I would informally consider the outcome of a die roll to be "random".
A die behaves randomly because it forms a chaotic system, that has an extreme sensitivity to the initial conditions. In other words, assuming you are able to throw the same die in the exact same conditions, but after is has lost a single atom, it can end-up on another face. Really.
And in fact, throwing in the exact same conditions is impossible because we can't control the state of a billion billion atoms simultaneously, which fluctuates in an extremely complex way due to thermal motion.
No computer on Earth could simulate the trajectory with enough accuracy.
A die can land on (finally)
1.either a face
2.one of twelve edges and always land on the side which makes angle less than 45 assuming sufficient friction.
3.On a corner and proceed to go on and land on the edge with angle less than 60
These are the only possible cases that come to mind finally after inelasticity of collisions leads to landing.
A mathematical model based on these cases could be drawn with parameters of initial potential and kinetic energies, momentum and angular momentum to predict which of the cases befall up until each bounce and until the energy is dissipated enough to predict a certain number on dice.
Procuring these four initial arguments with reasonable accuracy will give close to accurate number on dice.
I think the die is random because it BEHAVES AS IF it is random. Likewise, the pseudorandom generators in computers. The difference is that in the computer, you can reset the generator and get the exact same sequence; nobody I know has been able to do this with dice.
I heard of a long ago Soviet computer that had an actual random digit generator. I don't know if they used thermal noise or a radioactive decay detector, but it was abandoned because there was no way to repeat the exact same sequence when software was being debugged.
• Since 2013, the Intel processors (Ivy Bridge microarchitecture) feature a built-in hardware truly random number generator that exploits thermal noise. – Yves Daoust May 25 '17 at 21:37
• Thanks for that! Intel does a pretty good job of keeping the insides of our processors secret from us. Not like the old days of the 8080, when we knew all of the registers and could program them in machine language. – richard1941 May 29 '17 at 16:57
• I doubt the it was kept secret. As such a device is very handy in cryptographic applications (for which it was explicitly designed), they must have heaviliy advertized it at the time. spectrum.ieee.org/computing/hardware/… – Yves Daoust May 29 '17 at 17:31
|
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|
https://mathematica.stackexchange.com/questions/92851/solve-a-function-to-find-the-optimum-value-of-parameter-in-mathematica?noredirect=1
|
# Solve a function to find the optimum value of parameter in mathematica [duplicate]
I have a complicated function as shown
It doesn't have a standard integration as far as I know.
Now, numerical integration of the left hand side function over a set of points gives the right hand side value (sorry about the missing integration sign in the image).
I know the value of parameter $X0$ as constant and $x$ is the independent variable. I wish to extract parameter alpha which I know is a real number.
How shall I do that in Mathematica? I have tried FindRoot method,didn't work.
FindRoot[(NIntegrate[(Abs[
0.5*Sqrt[Pi/(alpha)]*
Exp[-((Pi*x)^2/(alpha))]*(1 -
Erf[(-32.3077)*Sqrt[(alpha)] +
I*Pi*x/Sqrt[(alpha)]])])^2, {x, 0.00081846, 0.000818573,
0.000818686, 0.0008188, 0.000818913, 0.000819026, 0.000819139,
0.000819253, 0.000819366, 0.000819479, 0.000819592, 0.000819706,
0.000819819, 0.000819932, 0.000820045, 0.000820159, 0.000820272,
0.000820385, 0.000820498, 0.000820612, 0.000820725, 0.000820838,
0.000820951, 0.000821065, 0.000821178, 0.000821291, 0.000821404,
0.000821518, 0.000821631, 0.000821744, 0.000821857, 0.000821971,
0.000822084, 0.000822197, 0.00082231, 0.000822424, 0.000822537,
0.00082265, 0.000822763, 0.000822877, 0.00082299, 0.000823103,
0.000823216, 0.00082333, 0.000823443, 0.000823556, 0.000823669,
0.000823783, 0.000823896, 0.000824009, 0.000824122, 0.000824236,
0.000824349, 0.000824462, 0.000824575, 0.000824689, 0.000824802,
0.000824915, 0.000825028}]) == 0.0139828, {alpha, 0.001}]
$X0$ for a particular case is -32.3077, becomes $0$ for particular $x$ and varies upto +30.3699 for different cases.
'alpha' for that particular X0 should come around 0.03 and thus alpha varies with $X0$
• 1) Add code to your question rather than an image. 2) Show us what you have tried so far, and why it didn't work. 3) Add the values of the constants in your expression. 4) what are the limits of integration? – MarcoB Sep 2 '15 at 19:33
• @MarcoB thanks for the reply, I have added my code sample kindly help me out. I hope I have addressed your requirements. – AVyas Sep 3 '15 at 8:42
• Links to answers for this issue are found in the section on NumericQ of this Q&A: What are the most common pitfalls awaiting new users? – Jens Sep 3 '15 at 17:05
• @Jens I thought of using f[alpha_?NumericQ, x_?NumericQ] := Abs[0.5*Sqrt[Pi/alpha]*Exp[-(Pi*x)^2/alpha]*(1 - Erf[-32.3077*Sqrt[alpha] + I*Pi*x/Sqrt[alpha]])]^2 followed by FindRoot[NIntegrate[f[alpha, x], ... in my answer, but the error message persisted. Of course, even the code in the question gives the correct answer despite the error message. – bbgodfrey Sep 3 '15 at 17:21
• I found another possible duplicate (this type of issue is so common that answers are scattered throughout this site): How can I get Mathematica to allow me to apply FindRoot to an expression that contains NIntegrate?. I think it's better not to add to this proliferation, so I still propose to close this question. – Jens Sep 3 '15 at 17:29
Adding the option, Evaluated -> False tells FindRoot not to evaluate the function (NIntegrate in this case) before inserting alpha.
FindRoot[NIntegrate[Abs[0.5*Sqrt[Pi/alpha]*Exp[-(Pi*x)^2/alpha]*(1 -
Erf[-32.3077*Sqrt[alpha] + I*Pi*x/Sqrt[alpha]])]^2,
{x, 0.00081846, 0.000818573,
0.000818686, 0.0008188, 0.000818913, 0.000819026, 0.000819139,
0.000819253, 0.000819366, 0.000819479, 0.000819592, 0.000819706,
0.000819819, 0.000819932, 0.000820045, 0.000820159, 0.000820272,
0.000820385, 0.000820498, 0.000820612, 0.000820725, 0.000820838,
0.000820951, 0.000821065, 0.000821178, 0.000821291, 0.000821404,
0.000821518, 0.000821631, 0.000821744, 0.000821857, 0.000821971,
0.000822084, 0.000822197, 0.00082231, 0.000822424, 0.000822537,
0.00082265, 0.000822763, 0.000822877, 0.00082299, 0.000823103,
0.000823216, 0.00082333, 0.000823443, 0.000823556, 0.000823669,
0.000823783, 0.000823896, 0.000824009, 0.000824122, 0.000824236,
0.000824349, 0.000824462, 0.000824575, 0.000824689, 0.000824802,
0.000824915, 0.000825028}] == 0.0139828, {alpha, 0.001},
Evaluated -> False]
(* {alpha -> 0.00132634} *)
Incidentally, the expression in the question contains many unnecessary pairs of parentheses. Although not harmful, they make the expression longer and, for me, more difficult to read.
|
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|
https://www.arxiv-vanity.com/papers/0711.3785/
|
# Unprovability results involving braids
Lorenzo CARLUCCI Università di Roma “La Sapienza”, Department of Computer Science, Via Salaria 113, 00198 Roma, Italy
and
Scuola Normale Superiore di Pisa, Classe di Lettere, Piazza dei Cavalieri, 56126 Pisa, Italy
Patrick DEHORNOY Laboratoire de Mathématiques Nicolas Oresme, UMR 6139 CNRS, Université de Caen BP 5186, 14032 Caen, France //www.math.unicaen.fr/dehornoy and Andreas WEIERMANN Vakgroep Zuivere Wiskunde en Computeralgebra Ghent University, Krijgslaan 281, Gebouw S22, B9000 Gent, Belgium
###### Abstract.
We construct long sequences of braids that are descending with respect to the standard order of braids (“Dehornoy order”), and we deduce that, contrary to all usual algebraic properties of braids, certain simple combinatorial statements involving the braid order are true, but not provable in the subsystems or of the standard Peano system.
###### Key words and phrases:
braid group, braid ordering, hydra game, unprovability statements
###### 1991 Mathematics Subject Classification:
03B30, 03F35, 20F36, 91A50
L. C. was partially supported by Telecom Italia “Progetto Italia” grant; L. C. and A. W. were supported by NWO grant number 613080000.
It has been known for decades that there exist strong limitations about the sentences possibly provable from the axioms of a given formal system, starting with Gödel’s famous theorems implying that certain arithmetic sentences cannot be proved from the axioms of the first-order Peano system. However, the so-called Gödel sentences have a strong logical flavour and they remain quite remote from the sentences usually considered by mainstream mathematicians. It is therefore natural to look for further sentences that are true but unprovable from the Peano axioms, or from the axioms of other formal systems, and, at the same time, involve objects and properties that are both simple and natural. The main results so far in this direction involve finite combinatorics, Ramsey Theory and the theory of well-quasi-orders. See [9, 35] for a comprehensive bibliography.
On the other hand, Artin’s braid groups are algebraic structures which play a central role in many areas of mathematics and theoretical physics [8, 25]. It has been known since 1992 that, for each , the group of -strand braids is equipped with a canonical left-invariant ordering [16], and one of the most remarkable properties of this ordering is the result, due to R. Laver [28], that its restriction to the submonoid of consisting of the so-called Garside positive braids is a well-order, i.e., every nonempty subset of has a least element. It was proved by S. Burckel in [11] that the order-type of this restriction is the ordinal , hence it is rather large in the hierarchy of well-orders. It follows that, although the existence of infinite descending sequences in is forbidden by the well-order property, there may exist long finite descending sequences.
What we do in this paper is to investigate the existence of such long descending sequences in from the viewpoint of provability in and , the subsystems of the Peano system in which the induction scheme restricted to and sentences respectively, where a sentence is if it is of the form , with quantifiers and containing bounded quantifiers only—see Appendix for complete definitions; more generally, the few notions from logic needed for the paper are recalled there. We establish two types of unprovability results, that we now state in the context of , i.e., of -strand braids. First, we introduce particular long descending sequences of braids, called -sequences, by a simple recursive process. Then we prove
###### Proposition A.
For each initial braid in , the -sequence from is finite.
###### Theorem A.
Proposition A is an arithmetic statement111By an arithmetic statement we mean a first-order sentence in the language of Peano Arithmetic. As it stands, Proposition A involves braids, and therefore it is not an arithmetic statement; what we mean is that Proposition A can be encoded into an arithmetic statement in a way whose correctness can be established using the axioms of . that is not provable from the axioms of .
By contrast, it should be emphasized that much of the usual properties of braids, in particular all known algebraic properties, can, when properly encoded, be proved from the axioms of —as do most of the usual mathematical results that are formalizable in that system.
The second family of results involves general descending sequences of braids, and not only those called -sequences in Proposition A. For each function of to , we introduce a certain combinatorial principle that, roughly speaking, says that each descending sequence in in which the Garside complexity of the th braid entry remains below has a bounded length. We establish
###### Proposition B.
For each function , the principle is true.
But, denoting by the standard Ackermann function—see Appendix—and by the level approximation to , and using for the functional inverse of , we prove
###### Theorem B.
For , let be defined by , and be defined by .
For each , the principle is provable from the axioms of .
The principle is not provable from the axioms of .
The functions involved in Theorem B all are of the form where is a very slowly increasing function. Analogous to the results of [35, 36, 37], Theorem B is a typical example of a so-called phase transition phenomenon, in which a seemingly small change of the parameters causes a jump from provability to unprovability, here with respect to .
In some sense, the above results about -strand braids, as well as their extensions involving arbitrary braids, are not surprising. As -strand braids (resp. general braids) are equipped with a well-ordering of length (resp. ), a connection with the system (resp. ) can even be expected, because of the well-known connection of the latter ordinal with that logical system—cf. for instance Simpson’s analysis of the Hilbert and Robson basis theorems in [32]. The results we establish are reminiscent of analogous results established in the language of ordinals and trees. For instance, our -sequences are direct cousins of the Goodstein sequences and the Hydra battles [26] as well as of the more recent Worm Principle [5, 27]. However, our results are not just artificial translations of existing properties into the language of braids. The braid order is arguably a quite natural object, and all arguments developed in this paper rely on the specific properties of braids and their order, and not on an automated translation into another context. Typically, Propositions A and B directly follow from the very definition of the braid ordering and its well-foundedness, while Theorems A and B rely on some non-trivial analysis of the braid order on and its connection with Garside’s theory. The reason that makes the current results essentially nontrivial is that, although the well-order on positive braids is just a copy of the well-order on ordinals—according to the general uniqueness theorem of well-orders of a given length—the actual order isomorphism between braids and ordinals is not simple. This explains in particular why relatively sophisticated braid arguments are needed here. At the very least, one of the interests in the current approach is that it led to interesting braid questions that could be solved only at the expense of developing new tools, such as the counting results of Section 3.3 or the decomposition results of Section 4.1.
The paper is organized as follows. Section 1 contains a brief introduction to braid groups, their ordering, and to the so-called -normal form of -strand braids, all needed to state the subsequent results. In Section 2, we describe the -sequences, and establish Proposition A and Theorem A. In Section 3, we introduce the combinatorial principle , and establish Proposition B and Theorem B. Finally, in Section 4, we show how to extend Proposition A and Theorem A into similar results involving general braids and -provability. We also raise a few questions and point to further research. Finally, we provide in an appendix the needed basic definitions from logic, about ordinals and about basic subsystems of Peano arithmetic.
## 1. The general braid context
We briefly recall definitions for the braid group , the braid monoid , and the canonical braid order that will be the central object of investigation in the subsequent sections. The main point is the connection between the braid order on and the so-called -normal form.
### 1.1. Braid groups
For , the -strand braid group is the group of isotopy classes of geometric -strand braids [8, 25]. For our current purpose, it is sufficient to know that is the group with presentation
(1.1) ⟨σ\vruleheight5.0ptwidth0.0pt1,...,σ\vruleheight5.0ptwidth0.0ptn−1;σ\vruleheight5.0ptwidth0.0ptiσ\vruleheight5.0ptwidth0.0ptj=σ\vruleheight5.0ptwidth0.0ptjσ\vruleheight5.0ptwidth0.0ptifor % |i−j|⩾2,σ\vruleheight5.0ptwidth0.0ptiσ\vruleheight5.0ptwidth0.0ptjσ\vruleheight5.0ptwidth0.0pti=σ\vruleheight5.0ptwidth0.0ptjσ\vruleheight5.0ptwidth0.0ptiσ\vruleheight5.0ptwidth0.0ptjfor |i−j|=1⟩,
so that every element of , called an -braid in the sequel, is an equivalence class of words on the letters , …, with respect to the congruence generated by the relations of (1.1).
The connection with geometry is as follows. Associate with every -strand braid word a braid diagram by concatenating the elementary diagrams of Figure 1 corresponding to the successive letters of . Such a diagram can be seen as a plane projection of a three-dimensional figure consisting on disjoint curves. Then, the relations of (1.1) are a translation of ambient isotopy, i.e., of continuously moving the curves without moving their ends and without allowing them to intersect. It is easy to check that the relations of (1.1) correspond to such isotopies; the converse implication, i.e., the fact that the projections of isotopic three-dimensional geometric braids always can be encoded in words connected by (1.1), was proved by E. Artin in [4].
|
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|
https://atmos.ut.ee/et/publication/isi-000184868000005/
|
# Simulation of atmospheric nucleation mode: A comparison of nucleation models and size distribution representations
### Abstract
Atmospheric particle formation and growth were investigated using different nucleation models and size distribution representations. Nucleation was modeled using recently developed parameterizations for binary nucleation of water and sulphuric acid and ternary nucleation of water, sulphuric acid, and ammonia. A comparison with older nucleation parameterizations, combined with full aerosol dynamics, demonstrated that the difference in nucleation rate (1-2 orders of magnitude) is clearly reflected in the resulting total particle concentration. A comparison of binary and ternary nucleation schemes showed that above 240 K the ternary nucleation rate exceeds the binary by over 10 orders of magnitude, indicating that in most cases, at lower tropospheric conditions, only ternary nucleation can be relevant. In addition, the performance of aerosol dynamics models applying either a multimodal monodisperse or a fixed sectional size distribution representation was evaluated against a molecular resolution model, which follows the changes in the nucleation mode particle size distribution molecule by molecule. Regarding total number concentration, the sectional method converged to the molecular resolution approach when increasing the number of size sections. With strong condensational growth, however, numerical diffusion problems were evident. Overall, the performance of the sectional method with low number of sections was not satisfactory. The monodisperse method gave very good results, at least in terms of total number, when the background modes were set to match the condensation sinks of respective lognormal modes. On the basis of our study the multimodal monodisperse method seems to be a possible candidate when selecting the size distribution approach for large-scale atmospheric models.
Type
Publication
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
|
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|
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