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Virtual directory
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Disadvantages
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The classical virtual directory based on proxy cannot modify underlying data structures or create new views based on the relationships of data from across multiple systems. So if an application requires a different structure, such as a flattened list of identities, or a deeper hierarchy for delegated administration, a virtual directory is limited.
Many virtual directories cannot correlate same-users across multiple diverse sources in the case of duplicate users Virtual directories without advanced caching technologies cannot scale to heterogeneous, high-volume environments.
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Virtual directory
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Sample terminology
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Unify metadata: Extract schemas from the local data source, map them to a common format, and link the same identities from different data silos based on a unique identifier.
Namespace joining: Create a single large directory by bringing multiple directories together at the namespace level. For instance, if one directory has the namespace "ou=internal,dc=domain,dc=com" and a second directory has the namespace "ou=external,dc=domain,dc=com," then creating a virtual directory with both namespaces is an example of namespace joining.
Identity joining: Enrich identities with attributes pulled from multiple data stores, based on a link between user entries. For instance if the user joeuser exists in a directory as "cn=joeuser,ou=users" and in a database with a username of "joeuser" then the "joeuser" identity can be constructed from both the directory and the database.
Data remapping: The translation of data inside of the virtual directory. For instance, mapping “uid” to “samaccountname,” so a client application that only supports a standard LDAP-compliant data source is able to search an Active Directory namespace, as well.
Query routing: Route requests based on certain criteria, such as “write operations going to a master, while read operations are forwarded to replicas.” Identity routing: Virtual directories may support the routing of requests based on certain criteria (such as write operations going to a master while read operations being forwarded to replicas).
Authoritative source: A "virtualized" data repository, such as a directory or database, that the virtual directory can trust for user data.
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Virtual directory
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Sample terminology
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Server groups: Group one or more servers containing the same data and functionality. A typical implementation is the multi-master, multi-replica environment in which replicas process "read" requests and are in one server group, while masters process "write" requests and are in another, so that servers are grouped by their response to external stimuli, even though all share the same data.
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Virtual directory
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Use cases
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The following are sample use cases of virtual directories: Integrating multiple directory namespaces to create a central enterprise directory.
Supporting infrastructure integrations after mergers and acquisitions.
Centralizing identity storage across the infrastructure, making identity information available to applications through various protocols (including LDAP, JDBC, and web services).
Creating a single access point for web access management (WAM) tools.
Enabling web single sign-on (SSO) across varied sources or domains.
Supporting role-based, fine-grained authorization policies Enabling authentication across different security domains using each domain’s specific credential checking method.
Improving secure access to information both inside and outside of the firewall.
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Ice–albedo feedback
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Ice–albedo feedback
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Ice–albedo feedback is a positive feedback climate process where a change in the area of ice caps, glaciers, and sea ice alters the albedo and surface temperature of a planet. Ice is very reflective, therefore it reflects far more solar energy back to space than the other types of land area or open water. Ice–albedo feedback plays an important role in global climate change. For instance, at higher latitudes, warmer temperatures melt the ice sheets. However, if warm temperatures decrease the ice cover and the area is replaced by water or land, the albedo would decrease. This increases the amount of solar energy absorbed, leading to more warming. The change in albedo acts to reinforce the initial alteration in ice area leading to more warming. Warming tends to decrease ice cover and hence decrease the albedo, increasing the amount of solar energy absorbed and leading to more warming. In the geologically recent past, the ice–albedo positive feedback has played a major role in the advances and retreats of the Pleistocene (~2.6 Ma to ~10 ka ago) ice sheets. Inversely, cooler temperatures increase ice, which increases albedo, leading to more cooling.
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Ice–albedo feedback
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Significance
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Current Snow– and ice–albedo feedback have a substantial effect on regional temperatures. In particular, the presence of ice cover makes the North Pole and the South Pole colder than they would have been without it. Consequently, recent Arctic sea ice decline is one of the primary factors behind the Arctic warming nearly four times faster than the global average since 1979 (the year when continuous satellite readings of the Arctic sea ice began)., in a phenomenon known as Arctic amplification. Modelling studies show that strong Arctic amplification only occurs during the months when significant sea ice loss occurs, and that it largely disappears when the simulated ice cover is held fixed. Conversely, the high stability of ice cover in Antarctica, where the thickness of the East Antarctic ice sheet allows it to rise nearly 4 km above the sea level, means that this continent has not experienced any net warming over the past seven decades: ice loss in the Antarctic and its contribution to sea level rise is instead driven entirely by the warming of the Southern Ocean, which had absorbed 35–43% of the total heat taken up by all oceans between 1970 and 2017.Ice–albedo feedback also has a smaller, but still notable effect on the global temperatures. Arctic ice decline between 1979 and 2011 is estimated to have been responsible for 0.21 watts per square meter (W/m2) of radiative forcing, which is equivalent to a quarter of radiative forcing from CO2 increases over the same period. When compared to cumulative increases in greenhouse gas radiative forcing since the start of the Industrial Revolution, it is equivalent to the estimated 2019 radiative forcing from nitrous oxide (0.21 W/m2), nearly half of 2019 radiative forcing from methane (0.54 W/m2) and 10% of the cumulative CO2 increase (2.16 W/m2).
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Ice–albedo feedback
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Significance
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Future The impact of ice-albedo feedback on temperature will intensify in the future as the Arctic sea ice decline is projected to become more pronounced, with a likely near-complete loss of sea ice cover (falling below 1 million km2) at the end of the Arctic summer in September at least once before 2050 under all climate change scenarios, and around 2025 under the scenario of continually accelerating greenhouse gas emissions. Since September marks the end of the Arctic summer, it also represents the nadir of sea ice cover in the present climate, with an annual recovery process beginning in the Arctic winter. Consecutive ice-free Septembers are considered highly unlikely in the near future, but their frequency will increase with greater levels of global warming: a 2018 paper estimated that an ice-free September would occur once in every 40 years under a warming of 1.5 °C (2.7 °F), but once in every 8 years under 2 °C (3.6 °F) and once in every 1.5 years under 3 °C (5.4 °F). This means that the loss of Arctic sea ice during September or earlier in the summer would not be irreversible, and in the scenarios where global warming begins to reverse, its annual frequency would begin to go down as well. As such, it is not considered one of the tipping points in the climate system.
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Ice–albedo feedback
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Significance
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Notably, while the loss of sea ice cover in September would be a historic event with significant implications for Arctic wildlife like polar bears, its impact on the ice-albedo feedback is relatively limited, as the total amount of solar energy received by the Arctic in September is already very low. On the other hand, even a relatively small reduction in June sea ice extent would have a far greater effect, since June represents the peak of the Arctic summer and the most intense transfer of solar energy. CMIP5 models estimate that a total loss of Arctic sea ice cover from June to September would increase the global temperatures by 0.19 °C (0.34 °F), with a range of 0.16–0.21 °C, while the regional temperatures would increase by over 1.5 °C (2.7 °F). This estimate includes not just the ice-albedo feedback itself, but also its second-order effects such the impact of such sea ice loss on lapse rate feedback, the changes in water vapor concentrations and regional cloud feedbacks. Since these calculations are already part of every CMIP5 and CMIP6 model, they are also included in their warming projections under every climate change pathway, and do not represent a source of "additional" warming on top of their existing projections.
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Ice–albedo feedback
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Significance
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Very high levels of global warming could prevent Arctic sea ice from reforming during the Arctic winter. Unlike an ice-free summer, this ice-free Arctic winter may represent an irreversible tipping point. It is most likely to occur at around 6.3 °C (11.3 °F), though it could potentially occur as early as 4.5 °C (8.1 °F) or as late as 8.7 °C (15.7 °F). While the Arctic sea ice would be gone for an entire year, it would only have an impact on the ice-albedo feedback during the months where sunlight is received by the Arctic - i.e. from March to September. The difference between this total loss of sea ice and its 1979 state is equivalent to a trillion tons of CO2 emissions - around 40% of the 2.39 trillion tons of cumulative emissions between 1850 and 2019, although around a quarter of this impact has already happened with the current sea ice loss. Relative to now, an ice-free winter would have a global warming impact of 0.6 °C (1.1 °F), with a regional warming between 0.6 °C (1.1 °F) and 1.2 °C (2.2 °F).
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Ice–albedo feedback
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Significance
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Ice–albedo feedback also exists with the other large ice masses on the Earth's surface, such as mountain glaciers, Greenland ice sheet, West Antarctic and East Antarctic ice sheet. However, their large-scale melt is expected to take centuries or even millennia, and any loss in area between now and 2100 will be negligible. Thus, climate change models do not include them in their projections of 21st century climate change: experiments where they model their disappearance indicate that the total loss of the Greenland Ice Sheet adds 0.13 °C (0.23 °F) to global warming (with a range of 0.04–0.06 °C), while the loss of the West Antarctic Ice Sheet adds 0.05 °C (0.090 °F) (0.04–0.06 °C), and the loss of mountain glaciers adds 0.08 °C (0.14 °F) (0.07–0.09 °C). Since the East Antarctic ice sheet would not be at risk of complete disappearance until the very high global warming of 5–10 °C (9.0–18.0 °F) is reached, and since its total melting is expected to take a minimum of 10,000 years to disappear entirely even then, it is rarely considered in such assessments. If it does happen, the maximum impact on global temperature is expected to be around 0.06 °C (0.11 °F). Total loss of the Greenland ice sheet would increase regional temperatures in the Arctic by between 0.5 °C (0.90 °F) and 3 °C (5.4 °F), while the regional temperature in Antarctica is likely to go up by 1 °C (1.8 °F) after the loss of the West Antarctic ice sheet and 2 °C (3.6 °F) after the loss of the East Antarctic ice sheet.
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Ice–albedo feedback
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Significance
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Snowball Earth The runaway ice–albedo feedback was also important for the Snowball Earth. Geological evidence show glaciers near the equator, and models have suggested the ice–albedo feedback played a role. As more ice formed, more of the incoming solar radiation was reflected back into space, causing temperatures on Earth to drop. Whether the Earth was a complete solid snowball (completely frozen over), or a slush ball with a thin equatorial band of water still remains debated, but the ice–albedo feedback mechanism remains important for both cases.
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Ice–albedo feedback
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Ice–albedo feedback on exoplanets
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On Earth, the climate is heavily influenced by interactions with solar radiation and feedback processes. One might expect exoplanets around other stars to also experience feedback processes caused by stellar radiation that affect the climate of the world. In modeling the climates of other planets, studies have shown that the ice–albedo feedback is much stronger on terrestrial planets that are orbiting stars (see: stellar classification) that have a high near-ultraviolet radiation.
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Quillen's theorems A and B
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Quillen's theorems A and B
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In topology, a branch of mathematics, Quillen's Theorem A gives a sufficient condition for the classifying spaces of two categories to be homotopy equivalent. Quillen's Theorem B gives a sufficient condition for a square consisting of classifying spaces of categories to be homotopy Cartesian. The two theorems play central roles in Quillen's Q-construction in algebraic K-theory and are named after Daniel Quillen.
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Quillen's theorems A and B
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Quillen's theorems A and B
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The precise statements of the theorems are as follows.
In general, the homotopy fiber of Bf:BC→BD is not naturally the classifying space of a category: there is no natural category Ff such that FBf=BFf . Theorem B constructs Ff in a case when f is especially nice.
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6162 aluminium alloy
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6162 aluminium alloy
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6162 aluminium alloy is an alloy in the wrought aluminium-magnesium-silicon family (6000 or 6xxx series). It is related to 6262 aluminium alloy in that Aluminum Association designations that only differ in the second digit are variations on the same alloy. It is similar to 6105 aluminium alloy, both in alloy composition and the fact that it is only really used in extrusions. However, as a wrought alloy, it can also be formed by rolling, forging, and similar processes, should the need arise. It is supplied in heat treated form. It can be referred to by the UNS designation A96162, and is covered by the standard ASTM B221: Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes.
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6162 aluminium alloy
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Chemical composition
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The alloy composition of 6162 aluminium is: Aluminium: 96.7 to 98.9% Chromium: 0.1% max Copper: 0.2% max Iron: 0.5% max Magnesium: 0.7 to 1.1% Manganese: 0.1% max Silicon: 0.4 to 0.8% Titanium: 0.1% max Zinc: 0.25% max Residuals: 0.15% max
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6162 aluminium alloy
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Properties
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Typical material properties for 6162 aluminum alloy include: Density: 2.70 g/cm3, or 169 lb/ft3.
Young's modulus: 70 GPa, or 10 Msi.
Ultimate tensile strength: 280 to 290 MPa, or 41 to 42 ksi.
Yield strength: 260 to 270 MPa, or 38 to 39 ksi.
Thermal Expansion: 21.9 μm/m-K.
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Propylene oxide
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Propylene oxide
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Propylene oxide is an acutely toxic and carcinogenic organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid with an odour similar to ether, is produced on a large scale industrially. Its major application is its use for the production of polyether polyols for use in making polyurethane plastics. It is a chiral epoxide, although it is commonly used as a racemic mixture.
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Propylene oxide
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Propylene oxide
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This compound is sometimes called 1,2-propylene oxide to distinguish it from its isomer 1,3-propylene oxide, better known as oxetane.
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Propylene oxide
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Production
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Industrial production of propylene oxide starts from propylene. Two general approaches are employed, one involving hydrochlorination and the other involving oxidation. In 2005, about half of the world production was through chlorohydrin technology and one half via oxidation routes. The latter approach is growing in importance.
Hydrochlorination route The traditional route proceeds via the conversion of propene to propylene chlorohydrin according to the following simplified scheme: The mixture of 1-chloro-2-propanol and 2-chloro-1-propanol is then dehydrochlorinated. For example: Lime (calcium hydroxide) is often used to absorb the HCl.
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Propylene oxide
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Production
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Oxidation of propylene The other general route to propylene oxide involves oxidation of propylene with an organic peroxide. The reaction follows this stoichiometry: CH3CH=CH2 + RO2H → CH3CHCH2O + ROHThe process is practiced with four hydroperoxides: In the Halcon process, t-Butyl hydroperoxide derived from oxygenation of isobutane, which affords t-butanol. This coproduct can be dehydrated to isobutene, converted to MTBE, an additive for gasoline.
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Propylene oxide
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Production
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Ethylbenzene hydroperoxide, derived from oxygenation of ethylbenzene, which affords 1-phenylethanol. This coproduct can be dehydrated to give styrene, a useful monomer.
Cumene hydroperoxide derived from oxygenation of cumene (isopropylbenzene), which affords cumyl alcohol. Via dehydration and hydrogenation this coproduct can be recycled back to cumene. This technology was commercialized by Sumitomo Chemical.
Hydrogen peroxide is the oxidant in the hydrogen peroxide to propylene oxide (HPPO) process, catalyzed by a titanium-doped silicalite: C3H6 + H2O2 → C3H6O + H2OIn principle, this process produces only water as a side product. In practice, some ring-opened derivatives of PO are generated.
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Propylene oxide
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Reactions
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Like other epoxides, PO undergoes ring-opening reactions. With water, propylene glycol is produced. With alcohols, reactions, called hydroxylpropylation, analogous to ethoxylation occur. Grignard reagents add to propylene oxide to give secondary alcohols.
Some other reactions of propylene oxide include: Reaction with aluminium oxide at 250–260 °C leads to propionaldehyde and a little acetone.
Reaction with silver(I) oxide leads to acetic acid.
Reaction with sodium–mercury amalgam and water leads to isopropanol.
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Propylene oxide
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Uses
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Between 60 and 70% of all propylene oxide is converted to polyether polyols by the process called alkoxylation. These polyols are building blocks in the production of polyurethane plastics. About 20% of propylene oxide is hydrolyzed into propylene glycol, via a process which is accelerated by acid or base catalysis. Other major products are polypropylene glycol, propylene glycol ethers, and propylene carbonate.
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Propylene oxide
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Uses
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Niche uses Fumigant The United States Food and Drug Administration has approved the use of propylene oxide to pasteurize raw almonds beginning on September 1, 2007, in response to two incidents of contamination by Salmonella in commercial orchards, one incident occurring in Canada and one in the United States.
Pistachio nuts can also be subjected to propylene oxide to control Salmonella.
Microscopy Propylene oxide is commonly used in the preparation of biological samples for electron microscopy, to remove residual ethanol previously used for dehydration. In a typical procedure, the sample is first immersed in a mixture of equal volumes of ethanol and propylene oxide for 5 minutes, and then four times in pure oxide, 10 minutes each.
Munition Propylene oxide is sometimes used in thermobaric munitions as the fuel in fuel–air explosives. In addition to the explosive damage from the blast wave, unexploded propylene oxide can cause additional effects from direct toxicity.
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Propylene oxide
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Safety
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Propylene oxide is both acutely toxic and carcinogenic. Acute exposure causes respiratory tract irritation, eventually leading to death . Signs of toxicity after acute exposure include salivation, lacrimation, nasal discharge, gasping, lethargy and hypoactivity, weakness, and incoordination. Propylene oxide is also neurotoxic in rats, and presumably in humans Propylene oxide alkylates DNA. As such, it is known animal carcinogen and a potential human carcinogen, and is included into the List of IARC Group 2B carcinogens.
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Propylene oxide
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Natural occurrence
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In 2016 it was reported that propylene oxide was detected in Sagittarius B2, a cloud of gas in the Milky Way weighing three million solar masses. It is the first chiral molecule to be detected in space, albeit with no enantiomeric excess.
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Propylene oxide
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Cited sources
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Haynes WM, ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed.). Boca Raton, FL: CRC Press. ISBN 1-4398-5511-0.
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Epic Systems
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Epic Systems
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Epic Systems Corporation, or Epic, is an American privately held healthcare software company. According to the company, hospitals that use its software held medical records of 78% of patients in the United States and over 3% of patients worldwide in 2022.
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Epic Systems
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History
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Epic was founded in 1979 by Judith R. Faulkner with a $70,000 investment (equivalent to $280,000 in 2022). Originally headquartered in Madison, Wisconsin, Epic moved its headquarters to a large campus in the suburb of Verona, Wisconsin in 2005, where it employs 10,000 people as of 2019. The campus has themed areas/buildings, such as a castle-like structure, a "Wizard Campus" that appears to be inspired by J.K. Rowling's Harry Potter, and a dining facility designed to mimic a train station.As of 2015, the company was in the fifth phase of campus expansion with five new buildings each planned to be around 100,000 square feet. The company also has offices in Bristol, UK; 's-Hertogenbosch, Netherlands; Dubai, United Arab Emirates; Dhahran, Saudi Arabia; Helsinki, Finland; Melbourne, Australia; Singapore; Trondheim, Norway; and Søborg, Denmark.
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Epic Systems
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Product and market
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Epic primarily develops, manufactures, licenses, supports, and sells a proprietary electronic medical record software application, known in whole as 'Epic' or an Epic EMR. The company's healthcare software is centered on its Chronicles database management system. Epic's applications support functions related to patient care, including registration and scheduling; clinical systems for doctors, nurses, emergency personnel, and other care providers; systems for lab technologists, pharmacists, and radiologists; and billing systems for insurers. MyChart is used in the USA and other countries to access doctors’ records and for billing purposes. It is used by 150 million patients across the US.Epic also offers cloud hosting for customers that do not wish to maintain their own servers; and short-term optimization and implementation consultants through their wholly-owned subsidiary Boost, Inc.The company's competitors include Cerner, MEDITECH, Allscripts, athenahealth, and units of IBM, McKesson, and Siemens.The majority of U.S. News & World Report's top-ranked hospitals and medical schools use Epic. In 2003, Kaiser Permanente began using Epic for its electronic records system. Among many others, Epic provides electronic record systems for Cedars-Sinai Medical Center in Los Angeles, the Cleveland Clinic, Johns Hopkins Hospital, UC Davis Medical Center in Sacramento, and all Mayo Clinic campuses. Partners HealthCare began adopting Epic in 2015 in a project initially reported to cost $1.2 billion, which critics decried and which is greater than the cost of its buildings. By 2018, the total expenses for the project were $1.6 billion, with payments for the software itself amounting to less than $100 million and the majority of the costs caused by lost patient revenues, tech support and other implementation work.In 2022 Emory Healthcare, Baptist Health and Memorial Hermann Health System all switched to Epic from Cerner.
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Epic Systems
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Criticisms and controversies
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Data sharing Care Everywhere is Epic's health information exchange software, which comes with its electronic health record (EHR, or EMR) system. A 2014 article in The New York Times interviews two doctors who said that their Epic systems wouldn't allow them to share data with users of competitors' software in a way that will satisfy the Meaningful Use requirements of the HITECH Act. At first, Epic charged a fee to send data to some non-Epic systems. Epic said the yearly cost for an average-sized hospital was around $5,000 a year. However, after Congressional hearings, Epic and other major software vendors announced that they would suspend per-transaction sharing fees. Epic customers must still pay for one-time costs of linking Epic to each individual non-Epic system with which they wish to exchange data; in contrast, Epic's competitors have formed the CommonWell Health Alliance which set a common Interoperability Software standard for electronic health records. A 2014 report by the RAND Corporation noted the software was difficult and costly to use in conjunction with other billing systems. The report also cited other research showing that Epic's implementation in the Kaiser Permanente system led to efficiency losses.
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Epic Systems
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Criticisms and controversies
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In September 2017, Epic announced Share Everywhere, which allows patients to authorize any provider who has internet access to view their record in Epic and to send progress notes back. Share Everywhere was named Healthcare Dive's "Health IT Development of the Year" in 2017.
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Epic Systems
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Criticisms and controversies
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UK experience An Epic electronic health record system costing £200 million was installed at Cambridge University Hospitals NHS Foundation Trust in October 2014, the first installation of an Epic system in the UK.After 2.1 million records were transferred to Epic systems, it developed serious problems and the system became unstable. Ambulances were diverted to other hospitals for five hours and hospital consultants noted issues with blood transfusion and pathology services. Other problems included delays to emergency care and appointments, and problems with discharge letters, clinical letters and pathology test results. Chief information officer, Afzal Chaudhry, said "well over 90% of implementation proceeded successfully".In July 2015, the BBC reported that the hospital's finances were being investigated. In September 2015, both the CEO and CFO of the hospital resigned. Problems with the clinical-records system, which were said to have compromised the "ability to report, highlight and take action on data" and to prescribe medication properly, were held to be contributory factors in the organization's sudden failure. In February 2016, digitalhealth.net reported that Clare Marx, president of the Royal College of Surgeons of England and member of the NHS National Information Board, found that at the time of implementation, "staff, patients and management rapidly and catastrophically lost confidence in the system. That took months and a huge amount of effort to rebuild." Danish experience In 2016, Danish health authorities spent 2.8 billion DKK on the implementation of Epic in 18 hospitals in a region with 2.8 million residents. On May 20, Epic went live in the first hospital. Doctors and nurses reported chaos in the hospital and complained of a lack of preparation and training.Since some elements of the Epic system were not properly translated from English to Danish, physicians resorted to Google Translate. As one example, when inputting information about a patient's condition, physicians were given the option to report between the left and the "correct" leg, not the left and right legs. As of 2019, Epic had still not been fully integrated with Denmark's national medical record system. Danish anesthesiologist and computer architect Gert Galster worked to adapt the system. According to Galster, these Epic systems were designed specifically to fit the U.S. health care system, and could not be disentangled for use in Denmark.An audit of the implementation that voiced concerns was published in June 2018. At the end of 2018, 62% of physicians expressed they were not satisfied with the system and 71 physicians signed a petition calling for its removal.
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Epic Systems
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Criticisms and controversies
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Finnish experience In 2012, the Hospital District of Helsinki and Uusimaa (HUS) decided to replace several smaller health record systems with one district-wide system created by Epic. It was called Apotti and would be used by healthcare and social services for the 2.2 million residents in the HUS area. The Apotti system was selected as the provider in 2015 and implementation started in 2018. By November 2022, the Apotti system had cost 625 million euros.After the implementation, complaints from healthcare workers, especially from doctors, started accumulating. The system was accused of being too complicated and that its convoluted UI was endangering patient safety. For example, one patient was administered the wrong chemotherapeutic drug due to an unclear selection menu in the system.In July 2022, a formal complaint demanding that the issues in the system be fixed or the system be removed entirely was sent to the Finnish health care supervising body Valvira. The complaint was signed by 619 doctors that use Apotti.
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Epic Systems
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Criticisms and controversies
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Norwegian experience Central Norway started introducing Epic (branded “Helseplattformen”) in the winter 2023. After approximately two months, the public broadcaster NRK reported that around 25% of the doctors at the region's main hospital considered quitting their job, and that 40% were experiencing stress related health issues due to the new IT system. Previously, health personnel actively demonstrated against the software by marching though the city of Trondheim. Due to the chaos ensuing the introduction, including 16.000 letters not being sent to patients, the Norwegian CEO of the Helseplattformen IT project, Torbjørg Vanvik, had her employment ended by the board. Unexpected cost increases forced the authorities to decrease efforts in other areas, such as a planned initiative on mental health. Employee representatives state that the public will receive ”significantly worse services“.
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Epic Systems
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Criticisms and controversies
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COVID-19 response In 2020, the novel coronavirus pandemic spread in the United States. Epic Systems faced considerable criticism for their initial plan to have their 10,000 employees return to work on-campus. Employees expressed concern about returning to the office, with the first group being required to return as early as August 10 while the pandemic continued to spread. This plan was abandoned, and as of December 2020, employees were still able to work from home. The plan had come about despite a Dane County public health order requiring remote work "to the greatest extent possible." Criticism revolved in particular around the fact that employees were being ordered back to preserve the company "culture," despite CEO Judy Faulkner's admission that work was getting done remotely. According to The Capital Times, who interviewed 26 Epic employees about the plan, "13 [employees] said they have knowledge of managers being demoted for expressing concern about the company’s plans to bring its nearly 10,000 workers back" to on-campus work, and all requested anonymity for fear of employer retribution.In a survey of over 400 Epic employees, 89% of respondents expressed dissatisfaction with how Epic was handling the pandemic.
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Plexin
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Plexin
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A plexin is a protein which acts as a receptor for semaphorin family signaling proteins. It is classically known for its expression on the surface of axon growth cones and involvement in signal transduction to steer axon growth away from the source of semaphorin. Plexin also has implications in development of other body systems by activating GTPase enzymes to induce a number of intracellular biochemical changes leading to a variety of downstream effects.
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Plexin
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Structure
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Extracellular All plexins have an extracellular SEMA domain at their N-terminus. This is a structural motif common among all semaphorins and plexins and is responsible for this binding of semaphorin dimers, which are the native conformation for these ligands in vivo. This is followed by alternating plexin, semaphorin, and integrin (PSI) domains and immunoglobulin-like, plexin, and transcription factors (IPT) domains. Each of these is named for the proteins in which their structure is conserved. Collectively, the extracellular region resembles a curved stalk projecting in a clockwise direction.Before bindings its semaphorin dimer ligand, associations between the extracellular domains of pre-formed plexin dimers keeps their intracellular domains segregated and inactive. This allows for co-localization of plexin dimers to be primed for binding of semaphorin dimers and activation of intracellular machinery.
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Plexin
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Structure
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Intracellular Highly conserved intracellular domains consisting of a bipartite segment which functions as a GTPase-Activating Protein (GAP). Plexin is the only known receptor molecule to have a GAP domain. In the inactive state, these two sections are separated by a Rho-GTPase binding domain (RBD). When the RBD bind to a Rnd-family Rho-GTPases along with plexin dimerization and semaphoring binding, the intracellular segment undergoes conformational changes which allow the separate GAP domains to interact and become active in turning Rap family Rho-GTPases. These GTPases can have a number of downstream effects, but in particular to Plexin expressed on axonal growth cones, the concentration the secondary messenger cyclic guanosine monophosphate (cGMP) increases within the cell.
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Plexin
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Structure
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Classes Nine genes have been identified which divide plexins into four subclasses based on structure and homology. These genes include: Class A: PLXNA1, PLXNA2, PLXNA3, PLXNA4A Class B: PLXNB1, PLXNB2, PLXNB3 Class C: PLXNC1 Class D: PLXND1Class A plexins interact with neuropilin co-receptor proteins to strengthen semaphorin binding interactions without altering the mode of binding. The structure of the Class B plexins has an additional extracellular site for cleavage by convertases, enzymes which modify plexin precursor polypeptides into their final peptide sequence, as well as a structural PDZ interaction motif on its C-terminus. C-class plexins have fewer structural Methionine-Related Sequences (MRS) and IPT domains. D-class plexins have an additional modification in one of the MRS domains
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Plexin
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Function
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Plexin receptors largely act to signal the binding of semaphorin signaling proteins in a short-distance inhibitory manner. Each class of plexin has a range of specificity, meaning they could bind specifically to one or more semaphorin isomers. Plexins also have varying effects on development depending on their expression in different tissue types. Plexin receptors have implications in neural development and axon growth guidance, angiogenesis and heart development, skeletal and kidney morphogenesis, and in the immune system. Genetic knockout of plexins have shown to be lethal at embryonic stages due to severe developmental defects in body systems regulated by semaphorin-plexin signaling. Malfunction of the plexin signaling pathway has been implicated in human diseases including neurological disorders and cancers.
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Plexin
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Function
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Axon guidance Plexin receptors on axon growth cones receive local semaphorin signaling and impede growth in that direction.Plexin activation on growth cones results in actin and microtubule polymer destabilization as well as clathrin-mediated endocytosis, resulting in retraction of growth cone projections.
Angiogenesis and heart development PLXND1 is involved in guiding the growth of new blood vessels. Cells expressing Sema3E do not need additional vascularization. Developing vessels will have their growth towards these cells inhibited upon PLXND1 binding to Sema3E independent of Neuropilin.
PLXNA2 and PLXND1 modulate proper development of cardiac structures.
Skeletal and kidney development During development, PLXNA1 and PLXNA2 are expressed in chondrocytes and osteoblasts, implementing them in regulating bone homeostasis.
PLXND1 has a role in the formation of vertebral bodies of the spinal column by signaling for proper fusing and splitting of the axial elements.
PLXNB1 and PLXNB2 control branching of the ureter in the kidney by inhibiting and promoting it, respectively.
Immune system PLXNA1 promotes dendritic and T cell proliferation.
PLXNA4 inhibits T cell response, but promotes inflammatory cytokine production by macrophages.
PLXNB1 promotes B cell survival, as well as macrophage recruitment.
Role in intelligence In a genome-wide association study, plexins, which are mutated in several monogenic neurodevelopmental disorders, were significantly enriched for associations with high IQ.
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Smoked salmon cheesecake
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Smoked salmon cheesecake
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Cheesecake is a sweet dessert made with a soft fresh cheese (typically cottage cheese, cream cheese, quark or ricotta), eggs, and sugar. It may have a crust or base made from crushed cookies (or digestive biscuits), graham crackers, pastry, or sometimes sponge cake. Cheesecake may be baked or unbaked, and is usually refrigerated.
Vanilla, spices, lemon, chocolate, pumpkin, or other flavors may be added to the main cheese layer. Additional flavors and visual appeal may be added by topping the finished dessert with fruit, whipped cream, nuts, cookies, fruit sauce, chocolate syrup, or other ingredients.
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Smoked salmon cheesecake
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Culinary classification
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Modern cheesecake is not usually classified as an actual "cake", despite the name (compare with Boston cream "pie"). Some people classify it as a torte due to the usage of many eggs, which are the sole source of leavening, as a key factor. Others find compelling evidence that it is a custard pie, based on the overall structure, with the separate crust, the soft filling, and the absence of flour. Other sources identify it as a flan, or tart.
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Smoked salmon cheesecake
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Culinary classification
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Savoury cheesecakes Smoked salmon cheesecake is a savoury form, containing smoked salmon. It is most frequently served as an appetizer or a buffet item. Michael Portillo visited a family-run smokehouse on the Isle of Skye, Scotland during his Great British Railway Journeys series. After sampling their smoked salmon cheesecake he commented "you haven't lived till you've tasted this." A smoked salmon cheesecake was a prize-winning recipe in 1996 in Better Homes and Gardens' Prize Tested Recipe Contest. The recipe called for the use of Swiss cheese along with the more usual (for cheesecakes) Ricotta.
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Smoked salmon cheesecake
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History
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An ancient form of cheesecake may have been a popular dish in ancient Greece even prior to Romans' adoption of it with the conquest of Greece. The earliest attested mention of a cheesecake is by the Greek physician Aegimus (5th century BCE), who wrote a book on the art of making cheesecakes (πλακουντοποιικόν σύγγραμμα—plakountopoiikon sungramma). The earliest extant cheesecake recipes are found in Cato the Elder's De Agri Cultura, which includes recipes for three cakes for religious uses: libum, savillum and placenta. Of the three, placenta cake is the most like modern cheesecakes: having a crust that is separately prepared and baked.A more modern version called a sambocade, made with elderflower and rose water, is found in Forme of Cury, an English cookbook from 1390. On this basis, the English chef Heston Blumenthal argues that cheesecake is an English invention.
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Smoked salmon cheesecake
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History
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The modern cheesecake The English name cheesecake has been used only since the 15th century, and the cheesecake did not evolve into its modern form until somewhere around the 18th century. Europeans began removing yeast and adding beaten eggs to the cheesecake instead. With the overpowering yeast flavor gone, the result tasted more like a dessert treat. The early 19th-century cheesecake recipes in A New System of Domestic Cookery by Maria Rundell are made with cheese curd and fresh butter. One version is thickened with blanched almonds, eggs and cream, and the cakes may have included currants, brandy, raisin wine, nutmeg and orange flower water.
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Smoked salmon cheesecake
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History
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Modern commercial American cream cheese was developed in 1872, when William Lawrence, from Chester, New York, was searching for a way to recreate the soft, French cheese Neufchâtel. He discovered up with a way of making an "unripened cheese" that is heavier and creamier; other dairymen came up with similar creations independently.Modern cheesecake comes in two different types. Along with the baked cheesecake, some cheesecakes are made with uncooked cream cheese on a crumbled-cookie or graham cracker base. This type of cheesecake was invented in the United States.
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Smoked salmon cheesecake
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National varieties
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Cheesecakes can be broadly categorized into two basic types: baked and unbaked. Some do not have a crust or base. Cheesecake comes in a variety of styles based on region: Africa South Africa One popular variant of cheesecake in South Africa is made with whipped cream, cream cheese, gelatin for the filling, and a buttered digestive biscuit crust. It is not baked, and is sometimes made with Amarula liqueur. This variant is very similar to British cheesecake. This cheesecake is more common in British South African communities.
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Smoked salmon cheesecake
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National varieties
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Asia Japan Japanese cheesecake, or soufflé-style or cotton cheesecake, is made with cream cheese, butter, sugar, and eggs, and has a characteristically wobbly, airy texture, similar to chiffon cake. No-bake cheesecakes are known as rare cheesecake (Japanese: レアチーズケーキ).
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Smoked salmon cheesecake
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National varieties
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Philippines The most prominent version of cheesecake in the Philippines is ube cheesecake. It is made with a base of crushed graham crackers and an upper layer of cream cheese and ube halaya (mashed purple yam with milk, sugar, and butter). It can be prepared baked or simply refrigerated. Like other ube desserts in the Philippines, it is characteristically purple in color.
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Smoked salmon cheesecake
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National varieties
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Europe Spain Basque cheesecake was created in 1990 by Santiago Rivera of the La Viña restaurant in the Basque Country, Spain. It is composed of burnt custard and no crust. It achieved popularity online in the 2010s, helped by a recipe published by the British food writer Nigella Lawson. In 2023, the British restaurant critic Jay Rayner complained that Basque cheesecake had become overabundant in London.
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Smoked salmon cheesecake
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National varieties
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Russia Russian-style cheesecake (Vatrushka) is in the form of a dough ring and filled with quark or cottage cheese.
North America United States The United States has several different recipes for cheesecake and this usually depends on the region in which the cake is baked, as well as the cultural background of the person baking it.
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Smoked salmon cheesecake
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National varieties
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Chicago Chicago-style cheesecake is a baked cream cheese version that is firm on the outside with a soft and creamy texture on the inside. These cheesecakes are often made in a greased cake pan and are relatively fluffy in texture. The crust used with this style of cheesecake is most commonly made from shortbread that is crushed and mixed with sugar and butter. Some frozen cheesecakes are Chicago-style.
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Smoked salmon cheesecake
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National varieties
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New York New York–style cheesecake uses a cream cheese base, also incorporating heavy cream or sour cream. The typical New York cheesecake is rich and has a dense, smooth, and creamy consistency.
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Smoked salmon cheesecake
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Galleries
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Cheesecakes from around the world Fruit cheesecakes
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Avaya VSP 4000 series
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Avaya VSP 4000 series
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The Avaya Virtual Services Platform 4000 series (VSP 4000) are products that, in computer networking terms, are standalone switch/routers (layer 2/layer 3) designed and manufactured by Avaya for Ethernet-based networks. The VSP 4000 hardware is a derivative of the earlier Ethernet routing switch 4000 series, leveraging certain shared components, but implementing a new, completely different, operating system derived from the virtual service platform 9000 series. The role of the VSP 4000 is to extend fabric-based network virtualization services to smaller, remote locations, thereby creating a single service delivery network.
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Avaya VSP 4000 series
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Avaya VSP 4000 series
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The VSP 4000 offers a range of network virtualization services that are based on Avaya's extended implementation of Shortest Path Bridging; marketed as the 'Avaya VENA Fabric Connect' technology. The first software release supports: Layer 2 virtualized services that extend VLANs across the fabric (including across subnets and long distances) Layer 3 virtualized services that interconnect and extend VRFs across the fabric Native routing between layer 2 and layer 3 virtualized services for access to shared services IP shortcut routing that enables direct layer 3 connectivity between individual end-points without requiring deployment of an additional IGP (e.g. OSPF).These capabilities are positioned are supporting the following deployment scenarios: Virtualized small and mid-sized Enterprise Distributed enterpriseDeployments would be made to facilitate the following business situations: End-to-end traffic separation for multi-tenancy or for security / regulatory compliance (i.e. PCI DSS) Integrated video surveillance
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Avaya VSP 4000 series
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History
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The first VSP 4000 models were made available in April 2013.
The first models delivered in the series were: VSP 4850GTS, a 1RU Layer 2/Layer 3 Switch that is equipped with 48 x 10/100/1000BASE-T ports (including two common Uplink ports offering SFP connectivity) plus 2 x 10 Gigabit Ethernet ports that feature SFP+ physical connectivity.
VSP 4850GTS-PWR+, a similar product the VSP 4850GTS, with the addition of supporting 802.3at Power-over-Ethernet Plus (PoE+) on the copper ports.
VSP 4850GTS-DC, a similar product the VSP 4850GTS, but with DC power instead of AC.In June 2014, a further model was added: VSP 4450GSX-PWR+, a 1RU Layer 2/Layer 3 Switch that is equipped with 36 x 1000BASE-SFP ports, 12 x 10/100/1000BASE-T ports that support 802.3at PoE+, plus 2 x 10GBASE-SFP+ Ethernet ports (that also support Gigabit SFPs).
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Biopsychosocial model
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Biopsychosocial model
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Biopsychosocial models are a class of trans-disciplinary models which look at the interconnection between biology, psychology, and socio-environmental factors. These models specifically examine how these aspects play a role in topics ranging from human development, to health and disease, to information processing, and to conflict.
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Biopsychosocial model
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Biopsychosocial model
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According to Derick T. Wade and Peter W. Halligan, as of 2017, it is generally accepted that "illness and health are the result of an interaction between biological, psychological, and social factors."The term was first used to describe a model advocated by George L. Engel in 1977. It now also refers to any model which takes a similar approach, and has become an alternative to the biomedical and/or psychological dominance of many health care systems.
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Biopsychosocial model
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Biopsychosocial model
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Gender can be thought of as biopsychosocial, as it is a complex matter formed from social, psychological, and biological aspects.
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Biopsychosocial model
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History
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George L. Engel and Jon Romano of the University of Rochester in 1977, are widely credited with being the first to propose a biopsychosocial model. However, it had been proposed 100 years earlier and by others. Engel struggled with the then-prevailing biomedical approach to medicine as he strove for a more holistic approach by recognizing that each patient has their own thoughts, feelings, and history. In developing his model, Engel framed it for both illnesses and psychological problems.
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Biopsychosocial model
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History
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Engel's biopsychosocial model reflects the development of illness through the complex interaction of biological factors (genetic, biochemical, etc.), psychological factors (mood, personality, behaviour, etc.) and social factors (cultural, familial, socioeconomic, medical, etc.). For example, a person may have a genetic predisposition for depression, but they must have social factors such as extreme stress at work and family life and psychological factors such as a perfectionistic tendencies which all trigger this genetic code for depression. A person may have a genetic predisposition for a disease, but social and cognitive factors must trigger the illness.
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Biopsychosocial model
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History
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Specifically, Engel broadened medical thinking by re-proposing a separation of body and mind. The idea of mind–body dualism goes back at least to René Descartes, but was forgotten during the biomedical approach. Engel emphasized that the biomedical approach is flawed because the body alone does not contribute to illness. Instead, the individual mind (psychological and social factors) play a significant role in how an illness is caused and how it is treated. Engel proposed a dialogue between the patient and the doctor in order to find the most effective treatment solution.Similarly, materialistic and reductionist ideas proposed with the biomedical model are flawed because they cannot be verified on a cellular level (according to Engel). Instead, the proposed model focuses on the research of past psychologists such as Urie Bronfenbrenner, popularized by his belief that social factors play a role in developing illnesses and behaviors. Simply, Engel used Bronfenbrenner's research as a column of his biopsychosocial model and framed this model to display health at the center of social, psychological, and biological aspects.
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Biopsychosocial model
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History
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After publication, the biopsychosocial model was adopted by the World Health Organization (WHO) in 2002 as a basis for the International Classification of Function (ICF). However, The WHO definition of health adopted in 1948 clearly implied a broad socio-medical perspective.
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Biopsychosocial model
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Current status of the BPS model
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The biopsychosocial (BPS) model is still widely used as both a philosophy of clinical care and a practical clinical guide useful for broadening the scope of a clinician's gaze. Dr. Borrell-Carrió and colleagues reviewed Engel's model 25 years on. They proposed the model had evolved into a BPS and relationship-centered framework for physicians. They proposed three clarifications to the model, and identified seven established principles.
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Biopsychosocial model
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Current status of the BPS model
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Self-awareness.
Active cultivation of trust.
An emotional style characterized by empathic curiosity.
Self-calibration as a way to reduce bias.
Educating the emotions to assist with diagnosis and forming therapeutic relationships.
Using informed intuition.
Communicating clinical evidence to foster dialogue, not just the mechanical application of protocol.Gatchel and colleagues argued in 2007 the biopsychosocial model is the most widely accepted as the most heuristic approach to understanding and treating chronic pain.
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Biopsychosocial model
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Relevant theories and theorists
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Other theorists and researchers are using the term biopsychosocial, or sometimes bio-psycho-social to distinguish Engel's model.Lumley and colleagues used a non-Engel model to conduct a biopsychosocial assessment of the relationship between and pain and emotion. Zucker and Gomberg used a non-Engel biopsychosocial perspective to assess the etiology of alcoholism in 1986.Crittenden considers the Dynamic-Maturational Model of Attachment and Adaptation (DMM), to be a biopsychosocial model. It incorporates many disciplines to understand human development and information processing.Kozlowska's Functional Somatic Symptoms model uses a biopsychosocial approach to understand somatic symptoms. Siegel's Interpersonal Neurobiology (IPNB) model is similar, although, perhaps to distinguish IPNB from Engel's model, he describes how the brain, mind, and relationships are part of one reality rather three separate elements. Most trauma -and violence-informed care models are biopsychosocial models.
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Biopsychosocial model
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Biopsychosocial research
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Wickrama and colleagues have conducted several biopsychosocial-based studies examining marital dynamics. In a longitudinal study of women divorced midlife they found that divorce contributed to an adverse biopsychosocial process for the women. In another study of enduring marriages, they looked to see if hostile marital interactions in the early middle years could wear down couples regulator systems through greater psychological distress, more health-risk behaviors, and a higher body mass index (BMI). Their findings confirmed negative outcomes and increased vulnerability to later physical health problems for both husbands and wives.Kovacs and colleagues meta-study examined the biopsychosocial experiences of adults with congenital heart disease. Zhang and colleagues used a biopsychosocial approach to examine parents own physiological response when facing children's negative emotions, and how it related to parents’ ability to engage in sensitive and supportive behaviors. They found parents’ physiological regulatory functioning was an important factor in shaping parenting behaviors directed toward children's emotions.
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Biopsychosocial model
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Biopsychosocial research
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A biopsychosocial approach was used to assess race and ethnic differences in aging and to develop the Michigan Cognitive Aging Project. Banerjee and colleagues used a biopsychosocial narrative to describe the dual pandemic of suicide and COVID-19.
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Biopsychosocial model
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Potential applications
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When Engel first proposed the biopsychosocial model it was for the purpose of better understanding health and illness. While this application still holds true the model is relevant to topics such as health, medicine, and development. Firstly, as proposed by Engel, it helps physicians better understand their whole patient. Considering not only physiological and medical aspects but also psychological and sociological well-being. Furthermore, this model is closely tied to health psychology. Health psychology examines the reciprocal influences of biology, psychology, behavioral, and social factors on health and illness.
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Biopsychosocial model
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Potential applications
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One application of the biopsychosocial model within health and medicine relates to pain, such that several factors outside an individual's health may affect their perception of pain. For example, a 2019 study linked genetic and biopsychosocial factors to increased post-operative shoulder pain. Future studies are needed to model and further explore the relationship between biopsychosocial factors and pain.The developmental applications of this model are equally relevant. One particular advantage of applying the biopsychosocial model to developmental psychology is that it allows for an intersection within the nature versus nurture debate. This model provides developmental psychologists a theoretical basis for the interplay of both hereditary and psychosocial factors on an individual's development.
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Biopsychosocial model
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In gender
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Gender is thought of by some as biopsychosocial. According to the Gender Spectrum Organization, "A person's gender is the complex interrelationship between three dimensions: body, identity, and social gender."According to Alex Iantaffi and Meg-John Barker, biological, psychological, and social factors all feed back into each other in complex ways to form a person's gender.
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Biopsychosocial model
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Criticisms
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There have been a number of criticisms of Engel's biopsychosocial model. Benning summarized the arguments against the model including that it lacked philosophical coherence, was insensitive to patients' subjective experience, was unfaithful to the general systems theory that Engel claimed it be rooted in, and that it engendered an undisciplined eclecticism that provides no safeguards against either the dominance or the under-representation of any one of the three domains of bio, psycho, or social.Psychiatrist Hamid Tavakoli argues that Engel's BPS model should be avoided because it unintentionally promotes an artificial distinction between biology and psychology, and merely causes confusion in psychiatric assessments and training programs, and that ultimately it has not helped the cause of trying to de-stigmatize mental health. The perspectives model does not make that arbitrary distinction.A number of these criticisms have been addressed over recent years. For example, the BPS-Pathways model describes how it is possible to conceptually separate, define, and measure biological, psychological, and social factors, and thereby seek detailed interrelationships among these factors.While Engel's call to arms for a biopsychosocial model has been taken up in several healthcare fields and developed in related models, it has not been adopted in acute medical and surgical domains, as of 2017.
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PARP4
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PARP4
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Poly [ADP-ribose] polymerase 4 is an enzyme that in humans is encoded by the PARP4 gene.This gene encodes poly(ADP-ribosyl)transferase-like 1 protein, which is capable of catalyzing a poly(ADP-ribosyl)ation reaction. This protein has a catalytic domain which is homologous to that of poly (ADP-ribosyl) transferase, but lacks an N-terminal DNA binding domain which activates the C-terminal catalytic domain of poly (ADP-ribosyl) transferase. Since this protein is not capable of binding DNA directly, its transferase activity may be activated by other factors such as protein-protein interaction mediated by the extensive carboxyl terminus.
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PARP4
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Interactions
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PARP4 has been shown to interact with Major vault protein.
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PLK2
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PLK2
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Serine/threonine-protein kinase PLK2 is an enzyme that in humans is encoded by the PLK2 gene.Serum-inducible kinase is a member of the 'polo' family of serine/threonine protein kinases that have a role in normal cell division. [supplied by OMIM]
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Somatic nervous system
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Somatic nervous system
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The somatic nervous system (SNS), or voluntary nervous system is the part of the peripheral nervous system associated with the voluntary control of body movements via skeletal muscles.The somatic nervous system consists of nerves carrying afferent nerve fibers, which relay sensation from the body to the central nervous system (CNS), and nerves carrying efferent nerve fibers, which relay motor commands from the CNS to stimulate muscle contraction.The a- of afferent and the e- of efferent correspond to the prefixes ad- (to, toward) and ex- (out of).
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Somatic nervous system
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Structure
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There are 43 segments of nerves in the human body. With each segment, there is a pair of sensory and motor nerves. In the body, 31 segments of nerves are in the spinal cord and 12 are in the brain stem. Besides these, thousands of association nerves are also present in the body.Thus the somatic nervous system consists of two parts: Spinal nerves: They are mixed nerves that carry sensory information into and motor commands out of the spinal cord.
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Somatic nervous system
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Structure
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Cranial nerves: They are the nerve fibers that carry information into and out of the brain stem. They include smell, eye muscles, mouth, taste, ear, neck, shoulders, and tongue.
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Somatic nervous system
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Function
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The somatic nervous system controls all voluntary muscular systems within the body, and the process of voluntary reflex arcs.The basic route of nerve signals within the efferent somatic nervous system involves a sequence that begins in the upper cell bodies of motor neurons (upper motor neurons) within the precentral gyrus (which approximates the primary motor cortex). Stimuli from the precentral gyrus are transmitted from upper motor neurons, down the corticospinal tract, to lower motor neurons (alpha motor neurons) in the brainstem and ventral horn of the spinal cord: upper motor neurons release a neurotransmitter called glutamate from their axon terminal knobs, which is received by glutamate receptors on the lower motor neurons: from there, acetylcholine is released from the axon terminal knobs of alpha motor neurons and received by postsynaptic receptors (nicotinic acetylcholine receptors) of muscles, thereby relaying the stimulus to contract muscle fibers.
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Somatic nervous system
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Function
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Reflex arcs A reflex arc is a neural circuit that creates a more or less automatic link between a sensory input and a specific motor output. Reflex circuits vary in complexity—the simplest spinal reflexes are mediated by a two-element chain, of which in the human body there is only one, also called a monosynaptic reflex (there is only one synapse between the two neurones taking part in the arc: sensory and motor). The singular example of a monosynaptic reflex is the patellar reflex. The next simplest reflex arc is a three-element chain, beginning with sensory neurons, which activate interneurons inside of the spinal cord, which then activate motor neurons. Some reflex responses, such as withdrawing the hand after touching a hot surface, are protective, but others, such as the patellar reflex ("knee jerk") activated by tapping the patellar tendon, contribute to ordinary behavior.
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Somatic nervous system
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Other animals
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In invertebrates, depending on the neurotransmitter released and the type of receptor it binds, the response in the muscle fiber could either be excitatory or inhibitory. For vertebrates, however, the response of a skeletal striated muscle fiber to a neurotransmitter – always acetylcholine (ACh) – can only be excitatory.
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Cabin cruiser
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Cabin cruiser
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A cabin cruiser is a type of power boat that provides accommodation for its crew and passengers inside the structure of the craft.
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Cabin cruiser
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Cabin cruiser
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A cabin cruiser usually ranges in size from 7.6 to 13.7 m (25 to 45 ft) in length, with larger pleasure craft usually considered yachts. Many cabin cruisers can be recovered and towed with a trailer and thus easily stored on land, which reduces maintenance and expense. These craft are generally equipped with a head (toilet), a galley, and at least one berth. Most cabin cruisers usually have a small dining area and some have an aft cabin (a cabin to the rear of the cockpit, with a double bed). Some cabin cruisers are equipped with heating, air conditioning, and power generators. Most also have water heaters and shore power electric systems.The cabin cruiser provides many of the amenities of larger yachts, while costing much less and normally being fully operable by the owner, whereas larger yachts often require a professional crew.
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Cabin cruiser
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Cabin cruiser
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Most newer cabin cruisers are faster than older models because of improved aerodynamic and hydrodynamic designs. Cabin cruisers are generally able to handle the water well because of their size and give a stable ride. They are generally spacious in the cockpit (open seating area towards aft or centre).
In the UK, purpose-built cabin cruisers were popular on the canal network in the 1960s and 1970s. Leading manufacturers were Norman, Viking, Microplus, Freeman, and Dawncraft. Today, they are more commonly found on the navigable rivers rather than canals.
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Auxology
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Auxology
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Auxology (from Greek αὔξω, auxō, or αὐξάνω, auxanō 'grow'; and -λογία, -logia) is a meta-term covering the study of all aspects of human physical growth. (Although, it is also fundamental of biology.) Auxology is a multi-disciplinary science involving health sciences/medicine (pediatrics, general practice, endocrinology, neuroendocrinology, physiology, epidemiology), and to a lesser extent: nutrition science, genetics, anthropology, anthropometry, ergonomics, history, economic history, economics, socio-economics, sociology, public health, and psychology, among others.
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Auxology
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History of auxology
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""Ancient Babylonians and Egyptians left some writings on child growth and variation in height between ethnic groups. In the late 18th century, scattered documents of child growth started to appear in the scientific literature, the studies of Jamberts in 1754 and the annual measurements of the son of Montbeillard published by Buffon in 1777 being the most cited ones [1]. Louis René Villermé (1829) was the first to realize that growth and adult height of an individual depend on the country's socio-economic situation. In the 19th century, the number of growth studies rapidly increased, with increasing interest also in growth velocity [2]. Günther documented monthly height increments in a group of 33 boys of various ages [3]. Kotelmann [4] first noted the adolescent growth spurt. In fact, the adolescent growth spurt appears to be a novel achievement in the history of human growth and the amount and intensity of the spurt seems to be greatest in tall and affluent populations [5]. By the beginning of the 20th century, national growth tables were published for most European nations with data for height, weight, and attempts to relate weight and height, though none of these were references in the proper sense of the word as the data were usually derived from small and unrepresentative samples. After the 1930s X-ray imaging of hand and wrist became popular for determining bone age. Current auxo-logical knowledge is based on the large national studies performed in the 1950s, 1960s and the 1970s, many of them inaugurated by James Tanner [1]. In the late 1970s a new school of anthropometric history [6] emerged among historians and economists. The main aim of this school was to evaluate secular changes in conscript height during the last 100–200 years and to associate them with socio-economic changes and political events in the different countries [7]. In the 1980s and the 1990s new mathematical approaches have been added of which the LMS method has strongly been recommended for constructing modern growth reference tables [8,9]: M stands for mean, S stands for a scaling parameter, and L stands for the Box–Cox power that is required to transform the skewed data to normality. Meanwhile, many national and international growth references are based on this technology. And in view of the general idea of growth and adult height being a mirror of nutritional status, health and wealth [10], these techniques have generally been accepted for routine screening pro-grams in Public Health. Anthropometry has also been considered essential for security purposes, for the usability of industrial products, and it has become routine for car and clothing industries, for furniture, housing, and many other aspects of design in the modern environment. Growth is defined as an increase in size over time. But the rigid metric of physical time is not directly related to the tempo at which an organism develops, matures and ages. Calendar time differs in its meaning in a fast maturing and in a slow maturing organism. Fast maturing children appear tall and "older" than their calendar age suggests, late maturers appear "too young" and often short even though both may later reach the same adult size. Whereas metric scales exist for height, weight and other amplitude parameters, there are no continuous scales for maturation and developmental tempo. Instead we are used to work with substitutes like the 5-step Tanner scale for staging puberty, and age equivalents for describing bone..." is an excerpt taken from Human Growth and Development by Borms, J., R. Hauspie, A. Sand, C. Susanne, and M. Hebbelinck, edsFrom the taken section above we can see that ancient cultures left writings and indicators of growth from childhood into adulthood, such as the Ancient Babylonians and Egyptians. Though it wouldn't been until the later part of the 1700s that it would appear in scientific literature in the light of the Age of Enlightenment. A movement of philosophical and scientific advancement and understanding that dominated the western world in the 18th century. As the ideals and respect of science and mathematics grew we see such men as Louis-René Villermé a physician and economist begin to take interest and realize the growth of individuals into adulthood had factors in their socio-economic situation and status. From there the study would continue to grow at a rapid rate.
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Auxology
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History of auxology
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Contemporaries would then catch on reaching from the interest in Growth chart which kept marks on growth velocity into more medical sided interest for public health in the sense of tracking one's own growth and health to set standards.
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Auxology
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Auxology in relation to anthropology
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As Biological anthropology is a sub-field of anthropology that provides insight into the biological/physical perspective of human beings and our ancestors, one can easily see how auxology relates to the anthropological fields. This can be seen through the study of physical human development and growth to the slight Sexual dimorphism within Human along with the maturing of the body such as the physical change from childhood into adulthood.
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Auxology
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Auxology in relation to anthropology
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Auxology can also be used in the comparing of remains such as that of Neanderthal, Homo habilis and Australopithecus afarensis to any relation of Hominidae.
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Recombination hotspot
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Recombination hotspot
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Recombination hotspots are regions in a genome that exhibit elevated rates of recombination relative to a neutral expectation. The recombination rate within hotspots can be hundreds of times that of the surrounding region. Recombination hotspots result from higher DNA break formation in these regions, and apply to both mitotic and meiotic cells. This appellation can refer to recombination events resulting from the uneven distribution of programmed meiotic double-strand breaks.
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Recombination hotspot
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Meiotic recombination
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Meiotic recombination through crossing over is thought to be a mechanism by which a cell promotes correct segregation of homologous chromosomes and repair of DNA damages. Crossing over requires a DNA double-stranded break followed by strand invasion of the homolog and subsequent repair. Initiation sites for recombination are usually identified by mapping crossing over events through pedigree analysis or through analysis of linkage disequilibrium. Linkage disequilibrium has identified more than 30,000 hotspots within the human genome. In humans, the average number of crossover recombination events per hotspot is one crossover per 1,300 meioses, and the most extreme hotspot has a crossover frequency of one per 110 meioses.
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Recombination hotspot
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Genomic rearrangements
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Recombination can also occur due to errors in DNA replication that lead to genomic rearrangements. These events are often associated with pathology. However, genomic rearrangement is also thought to be a driving force in evolutionary development as it gives rise to novel gene combinations. Recombination hotspots may arise from the interaction of the following selective forces: the benefit of driving genetic diversity through genomic rearrangement coupled with selection acting to maintain favorable gene combinations.
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Recombination hotspot
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Initiation sites
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DNA contains "fragile sites" within the sequence that are more prone to recombination. These fragile sites are associated with the following trinucleotide repeats: CGG-CCG, GAG-CTG, GAA-TTC, and GCN-NGC. These fragile sites are conserved in mammals and in yeast, suggesting that the instability is caused by something inherent to the molecular structure of DNA and is associated with DNA-repeat instability. These fragile sites are thought to form hairpin structures on the lagging strand during replication from single-stranded DNA base-pairing with itself in the trinucleotide repeat region. These hairpin structures cause DNA breaks that lead to a higher frequency of recombination at these sites.Recombination hotspots are also thought to arise due to higher-order chromosome structure that make some areas of the chromosome more accessible to recombination than others. A double stranded-break initiation site was identified in mice and yeast, located at a common chromatin feature: the trimethylation of lysine 4 of histone H3 (H3K4me3).Recombination hotspots do not seem to be solely caused by DNA sequence arrangements or chromosome structure. Alternatively, initiation sites of recombination hotspots can be coded for in the genome. Through the comparison of recombination between different mouse strains, locus Dsbc1 was identified as a locus that contributes to the specification of initiation sites in the genome in at least two recombination hotspot locations. Additional crossing over mapping located the Dsbc1 locus to the 12.2 to 16.7-Mb region of mouse chromosome 17, which contains the PRDM9 gene. The PRDM9 gene encodes a histone methyltransferase in the Dsbc1 region, providing evidence of a non-random, genetic basis for recombination initiation sites in mice. Rapid evolution of the PRDM9 gene explains the observation that human and chimpanzees share few recombination hotspots, despite a high level of sequence identity.
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Recombination hotspot
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Transcription associated recombination
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Homologous recombination in functional regions of DNA is strongly stimulated by transcription, as observed in a range of different organisms. Transcription associated recombination appears to be due, at least in part, to the ability of transcription to open the DNA structure and enhance accessibility of DNA to exogenous chemicals and internal metabolites that cause recombinogenic DNA damages. These findings suggest that transcription-associated recombination may contribute significantly to recombination hotspot formation.
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Recombination hotspot
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Viral recombination hotspots
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Homologous recombination is very frequent in RNA viruses. Recombination frequently occurs among very similar viruses, where crossover sites may occur anywhere across the genome, but after selection pressure these sites tend to localize in certain regions/hotspots. For example, in Enteroviruses, recombination hotspots have been identified at the 5'UTR-capsid region junction, and at the beginning of the P2 region. These two hotspots flank the P1 region that encodes for the capsid. In coronaviruses, the Spike genomic region is a recombination hotspot.
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Wiener deconvolution
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Wiener deconvolution
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In mathematics, Wiener deconvolution is an application of the Wiener filter to the noise problems inherent in deconvolution. It works in the frequency domain, attempting to minimize the impact of deconvolved noise at frequencies which have a poor signal-to-noise ratio.
The Wiener deconvolution method has widespread use in image deconvolution applications, as the frequency spectrum of most visual images is fairly well behaved and may be estimated easily.
Wiener deconvolution is named after Norbert Wiener.
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