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http://tailieu.vn/doc/adaptive-wcdma-p8--256828.html
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Mô tả tài liệu
CDMA network In this chapter, we initiate discussion on CDMA network capacity. The issue will be revisited again later in Chapter 13 to include additional parameters in a more comprehensive way. 8.1 CDMA NETWORK CAPACITY For initial estimation of CDMA network capacity, we start with a simple example of single cell network with n users and signal parameters defined as in the list above. If αi is the power ratio of user i and the reference user with index 0, and Ni is the interference power density produced by user i defined as αi = Pi /P0 , i = 1, . ....
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https://science.sciencemag.org/content/334/6061/1385?ijkey=e8aaedd3b29e88d4bd4555d252c72db29bec70cb&keytype2=tf_ipsecsha
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Report
# Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum
See allHide authors and affiliations
Science 09 Dec 2011:
Vol. 334, Issue 6061, pp. 1385-1388
DOI: 10.1126/science.1203513
## Abstract
Assessing the impact of future anthropogenic carbon emissions is currently impeded by uncertainties in our knowledge of equilibrium climate sensitivity to atmospheric carbon dioxide doubling. Previous studies suggest 3 kelvin (K) as the best estimate, 2 to 4.5 K as the 66% probability range, and nonzero probabilities for much higher values, the latter implying a small chance of high-impact climate changes that would be difficult to avoid. Here, combining extensive sea and land surface temperature reconstructions from the Last Glacial Maximum with climate model simulations, we estimate a lower median (2.3 K) and reduced uncertainty (1.7 to 2.6 K as the 66% probability range, which can be widened using alternate assumptions or data subsets). Assuming that paleoclimatic constraints apply to the future, as predicted by our model, these results imply a lower probability of imminent extreme climatic change than previously thought.
Climate sensitivity is the change in global mean near-surface air temperature ΔSAT caused by an arbitrary perturbation ΔF (radiative forcing) of Earth’s radiative balance at the top of the atmosphere with respect to a given reference state. The equilibrium climate sensitivity for a doubling of atmospheric carbon dioxide (CO2) concentrations (ECS2xC) from preindustrial times has been established as a well-defined standard measure (1). Moreover, because transient (disequilibrium) climate change and impacts on ecological and social systems typically scale with ECS2xC, it is a useful and important diagnostic in climate modeling (1). Initial estimates of ECS2xC = 3 ± 1.5 K suggested a large uncertainty (2), which has not been reduced in the past 32 years despite considerable efforts (110). On the contrary, many recent studies suggest a small possibility of very high (up to 10 K and higher) values for ECS2xC (310), implying extreme climate changes in the near future, which would be difficult to avoid. Efforts to use observations from the past 150 years to constrain the upper end of ECS2xC have met with limited success, largely because of uncertainties associated with aerosol forcing and ocean heat uptake (8, 9). Data from the Last Glacial Maximum (LGM), 19,000 to 23,000 years ago, are particularly useful to estimate ECS2xC because large differences from preindustrial climate and much lower atmospheric CO2 concentrations [185 parts per million (ppm) versus 280 ppm preindustrial] provide a favorable signal-to-noise ratio, both radiative forcings and surface temperatures are relatively well constrained from extensive paleoclimate reconstructions and modeling (1113), and climate during the LGM was close to equilibrium, avoiding uncertainties associated with transient ocean heat uptake.
Here, we combine a climate model of intermediate complexity with syntheses of temperature reconstructions from the LGM to estimate ECS2xC using a Bayesian statistical approach. LGM, CO2 doubling, and preindustrial control simulations are integrated for 2000 years using an ensemble of 47 versions of the University of Victoria (UVic) climate model (14) with different climate sensitivities ranging from ECS2xC = 0.3 to 8.3 K considering uncertainties in water vapor, lapse rate and cloud feedback on the outgoing infrared radiation (fig. S1), as well as uncertainties in dust forcing and wind-stress response. The LGM simulations include larger continental ice sheets, lower greenhouse gas concentrations, higher atmospheric dust levels (fig. S2), and changes in the seasonal distribution of solar radiation [see supporting online material (SOM)]. We combine recent syntheses of global sea surface temperatures (SSTs) from the Multiproxy Approach for the Reconstruction of the Glacial Ocean (MARGO) project (12) and SATs over land, based on pollen evidence (13) with additional data from ice sheets and land and ocean temperatures (figs. S3 and S4; all reconstructions include error estimates). The combined data set covers over 26% of Earth’s surface (Fig. 1A).
Figure 2 compares reconstructed zonally averaged surface temperatures with model results. Models with ECS2xC < 1.3 K underestimate the cooling at the LGM almost everywhere, particularly at mid-latitudes and over Antarctica, whereas models with ECS2xC > 4.5 K overestimate the cooling almost everywhere, particularly at low latitudes. High-sensitivity models (ECS2xC > 6.3 K) show a runaway effect resulting in a completely ice-covered planet. Once snow and ice cover reach a critical latitude, the positive ice-albedo feedback is larger than the negative feedback because of reduced longwave radiation (Planck feedback), triggering an irreversible transition (fig. S5) (15). During the LGM, Earth was covered by more ice and snow than it is today, but continental ice sheets did not extend equatorward of ~40°N/S, and the tropics and subtropics were ice free except at high altitudes. Our model thus suggests that large climate sensitivities (ECS2xC > 6 K) cannot be reconciled with paleoclimatic and geologic evidence and hence should be assigned near-zero probability.
Posterior probability density functions (PDFs) of the climate sensitivity are calculated by Bayesian inference, using the likelihood of the observations ΔTobs given the model ΔTmod(ECS2xC) at the locations of the observations. The two are assumed to be related by an error term ε; ΔTobs = ΔTmod(ECS2xC) + ε, which represents errors in both the model (endogenously estimated separately for land and ocean; fig. S13) and the observations (fig. S3), including spatial autocorrelation. A Gaussian likelihood function and an autocorrelation length scale of λ = 2000 km are assumed. The choice of the autocorrelation length scale is motivated by the model resolution and by residual analysis. (See sections 5 and 6 in the SOM for a full description of the statistical method, assumptions, and sensitivity tests.)
The resulting PDF (Fig. 3), considering both land and ocean reconstructions, is multimodal and displays a broad maximum with a double peak between 2 and 2.6 K, smaller local maxima around 2.8 and 1.3 K, and vanishing probabilities below 1 K and above 3.2 K. The distribution has its mean and median at 2.2 and 2.3 K, respectively, and its 66 and 90% cumulative probability intervals are 1.7 to 2.6 K and 1.4 to 2.8 K, respectively. Using only ocean data, the PDF changes little, shifting toward slightly lower values (mean 2.1 K, median 2.2 K, 66% 1.5 to 2.5 K, and 90% 1.3 to 2.7 K), whereas using only land data leads to a much larger shift toward higher values (mean and median 3.4 K, 66% 2.8 to 4.1 K, and 90% 2.2 to 4.6 K).
The best-fitting model (ECS2xC = 2.4 K) reproduces well the reconstructed global mean cooling of 2.2 K (within two significant digits), as well as much of the meridional pattern of the zonally averaged temperature anomalies (correlation coefficient r = 0.8) (Fig. 2). Substantial discrepancies occur over Antarctica, where the model underestimates the observed cooling by almost 4 K, and between 45° to 50° in both hemispheres, where the model is also too warm. Simulated temperature changes over Antarctica show considerable spatial variations (Fig. 1B), with larger cooling of more than 7 K over the West Antarctic Ice Sheet. The observations are located along a strong meridional gradient (fig. S7). Zonally averaged cooling of air temperatures is about 7 K at 80°S, more consistent with the reconstructions than the simulated temperature change at the locations of the observations. Underestimated ice sheet height at these locations could be a reason for the bias (16), as could deficiencies of the simple energy balance atmospheric model component. Underestimated cooling at mid-latitudes for the best fitting model also points to systematic model problems, such as the neglect of wind or cloud changes.
Two-dimensional features in the reconstructions are less well reproduced by the model (r = 0.5) (Fig. 1). Large-scale patterns that are qualitatively captured (Fig. 1) are stronger cooling over land than over the oceans, and more cooling at mid- to high latitudes (except for sea ice covered oceans), which is contrasted by less cooling in the central Pacific and over the Southern Hemisphere subtropical oceans. Continental cooling north of 40°N of 7.7 K predicted by the best-fitting model is consistent with the independent estimate of 8.3 ± 1 K from inverse ice-sheet modeling (17).
Generally, the model solution is much smoother than the reconstructions, partly because of the simple diffusive energy balance atmospheric model component. The model does not simulate warmer surface temperatures anywhere, whereas the reconstructions show warming in the centers of the subtropical gyres in parts of the northwest Pacific, Atlantic, and Alaska. It systematically underestimates cooling over land and overestimates cooling of the ocean (fig. S8). The land-sea contrast, which is governed by less availability of water for evaporative cooling over land compared with the ocean (18), is therefore underestimated, consistent with the tension between the ECS2xC inferred from ocean-only versus land-only data (Fig. 3). A possible reason for this bias could be overestimated sea-to-land water vapor transport in the LGM model simulations, perhaps due to too high moisture diffusivities. Other model simplifications, such as neglecting changes in wind velocities and clouds or errors in surface albedo changes in the dynamic vegetation model component, could also contribute to the discrepancies. The ratio between low latitude (40° S to 40° N) land and sea temperature change in the best-fitting model is 1.2, which is lower than the modern ratio of 1.5 found in observations and modeling studies (19).
Despite these shortcomings, the best-fitting model is within the 1σ-error interval of the reconstructed temperature change in three quarters (75%, mostly over the oceans) of the global surface area covered by reconstructions (fig. S8). The model provides data-constrained estimates of global mean (including grid points not covered by data) cooling of near-surface air temperatures ΔSATLGM = –3.0 K [66% probability range (–2.1, –3.3), 90% (–1.7, –3.7)] and sea surface temperatures ΔSSTLGM = –1.7 K [66% (–1.1, –1.8), 90% (–0.9, –2.1)] during the LGM (including an increase of marine sea and air temperatures of 0.3 and 0.47 K, respectively, due to 120-m sea-level lowering; otherwise, ΔSATLGM = –3.3 K and ΔSSTLGM = –2.0 K).
The ranges of 66 and 90% cumulative probability intervals, as well as the mean and median ECS2xC values, from our study are considerably lower than previous estimates. The most recent assessment report from the Intergovernmental Panel on Climate Change (6), for example, used a most likely value of 3.0 K and a likely range (66% probability) of 2 to 4.5 K, which was supported by other recent studies (1, 2023).
We propose three possible reasons that our study yields lower estimates of ECS2xC than previous work that also used LGM data. First, the new reconstructions of LGM surface temperatures show less cooling than previous studies. Our best estimates for global mean (including grid points not covered by data) SAT and SST changes reported above are 30 to 40% smaller than previous estimates (21, 23). This is consistent with less cooling of tropical SSTs (–1.5 K, 30°S to 30°N) in the new reconstruction (12) compared with previous data sets (–2.7 K) (24). Tropical Atlantic SSTs between 20°S and 20°N are estimated to be only 2.4 K colder during the LGM in the new reconstruction compared with 3 K used in (23), explaining part of the difference between their higher estimates of ECS2xC and ΔSATLGM (–5.8 K).
The second reason is limited spatial data coverage. A sensitivity test excluding data from the North Atlantic leads to more than 0.5 K lower ECS2xC estimates (SOM section 7 and fig. S14 and S15). This shows that systematic biases can result from ignoring data outside selected regions, as done in previous studies (22, 23), and implies that global data coverage is important for estimating ECS2xC. Averaging over all grid points in our model leads to a higher global mean temperature (SST over ocean, SAT over land) change (–2.6 K) than using only grid points where paleoclimate data are available (–2.2 K), suggesting that the existing data set is still spatially biased toward low latitudes and/or oceans. Increased spatial coverage of climate reconstructions is therefore necessary to improve ECS2xC estimates.
A third reason may be the neglect of dust radiative forcing in some previous LGM studies (21) despite ample evidence from the paleoenvironmental record that dust levels were much higher (25, 26). Sensitivity tests (Fig. 3) (SOM section 7) show that dust forcing decreases the median ECS2xC by about 0.3 K.
Our estimated ECS2xC uncertainty interval is rather narrow, <1.5 K for the 90% probability range, with most (~75%) of the probability mass between 2 and 3 K, which arises mostly from the SST constraint. This sharpness may imply that LGM SSTs are a strong physical constraint on ECS2xC. However, it could also be attributable to overconfidence arising from physical uncertainties not considered here, or from misspecification of the statistical model.
To explore this, we conduct sensitivity experiments that perturb various physical and statistical assumptions (Fig. 3 and figs. S14 and S15). The experiments collectively favor sensitivities between 1 and 3 K. However, we cannot exclude the possibility that the analysis is sensitive to uncertainties or statistical assumptions not considered here, and the underestimated land/sea contrast in the model, which leads to the difference between land- and ocean-based estimates of ECS2xC, remains an important caveat.
Our uncertainty analysis is not complete and does not explicitly consider uncertainties in radiative forcing due to ice-sheet extent or different vegetation distributions. Our limited model ensemble does not scan the full parameter range, neglecting, for example, possible variations in shortwave radiation due to clouds. Nonlinear cloud feedback in different complex models make the relation between LGM and CO2 doubling–derived climate sensitivity more ambiguous than apparent in our simplified model ensemble (27). More work, in which these and other uncertainties are considered, will be required for a more complete assessment.
In summary, using a spatially extensive network of paleoclimate observations in combination with a climate model, we find that climate sensitivities larger than 6 K are implausible, and that both the most likely value and the uncertainty range are smaller than previously thought. This demonstrates that paleoclimate data provide efficient constraints to reduce the uncertainty of future climate projections.
## Supporting Online Material
www.sciencemag.org/cgi/content/full/science.1203513/DC1
Materials and Methods
SOM Text
Figs. S1 to S16
Table S1
References (28103)
## References and Notes
1. Acknowledgments: This work was supported by the Paleoclimate Program of the National Science Foundation through project PALEOVAR (06023950-ATM). Thanks to S. Harrison and two anonymous reviewers for thoughtful and constructive comments that led to substantial improvements in the paper.
View Abstract
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https://www.physicsforums.com/threads/extended-or-point-source.331664/
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# Extended or point source?
1. Aug 20, 2009
### mordeth
If you were using a single radio telescope (not an interferometer) how could you tell whether a radio source was a point source or extended source?
I have searched the internet far and wide for many hours trying to answer this - I know what the difference between a point source and extended source is, but I'm not sure whether the question is asking for a simple or technical explanation. Is it something to do with the radio telescope data or how the radiation from the source is spread out on the dish when its received?
Last edited: Aug 20, 2009
2. Aug 20, 2009
### jimgraber
I assume you mean the usual in-effect single-pixel radio telescope at a single point in time. Then it is pretty much impossible to tell the difference, I think. The usual method then is to look at different points at different times. i.e. scan out the image over time. You can then detect its size, assuming its pretty much a constant source and really bigger than one pixel.
Best,
Jim Graber
Similar Discussions: Extended or point source?
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https://ask.sagemath.org/question/10073/hidden-features-of-sage/?answer=14934
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# Hidden features of Sage edit
asked 2013-04-29 01:09:50 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
In the spirit of the StackOverflow threads of "hidden" language features, we can use this thread (community wiki) to aggregate useful but little-known features or tricks of Sage. Perhaps these can be collected and added to the documentation in the future.
edit retag close merge delete
Sort by » oldest newest most voted
answered 2013-04-29 01:17:51 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
In the command line, the underscore is a variable holding the result of the last output. This is very useful, e.g., for the following:
sage: integrate(cos(x), x)
sin(x)
sage: diff(_, x)
cos(x)
more
answered 2013-05-16 08:32:41 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
The import_statements() function, which allows to know what import statement should we do to use an object.
sage: import_statements('RDF')
from sage.rings.real_double import RDF
more
By the way, it would be http://www.faqtory.co/sky/ (useful) (if it doesn't already exist) to have a function to render LaTeX code to an image just large enough to fit the expression
( 2016-09-12 11:11:43 +0200 )edit
answered 2013-05-16 08:31:06 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
The preparser() function which allows to understand differences between Python and Sage parsers, and between .py and .sage files:
sage: 2^2
4
sage: preparser(False)
sage: 2^2
0
sage: 2**2
4
Conversely, the preparse() function tells you how Sage preparses the input:
sage: preparse('1.0+2^2')
"RealNumber('1.0')+Integer(2)**Integer(2)"
more
answered 2013-05-28 16:24:02 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
It is possible to delete user-defined variables, and reset Sage variables back to their default:
sage: a = 1 ; a
1
sage: reset()
sage: a
NameError: name 'a' is not defined
It is also possible to reset only a few things:
sage: a = b = c = 1
sage: reset(['a','b'])
sage: c
1
more
To create a tuple of variables x0,...,xk you can use var("x", n=k), e.g.
sage: var("x", n=10)
(x0, x1, x2, x3, x4, x5, x6, x7, x8, x9)
more
answered 2013-05-29 14:27:15 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
A very hidden feature of Python!
For faster code using itertools you may delete the reference at the end of the loop
sage: from itertools import combinations
sage: sage: timeit('for p in combinations(range(18),5): pass')
625 loops, best of 3: 615 µs per loop
sage: sage: timeit('for p in combinations(range(18),5): del p')
625 loops, best of 3: 322 µs per loop
The reason is that the iterators in itertools recycle the objects they return if they are the only one to reference it! But is it relevant to optimize Python code?
more
Wow, this is really cool! Is there any documentation anywhere for this?
( 2013-06-03 00:51:55 +0200 )edit
1
Actually not ! You have to read the sources of Python to discover that fact. I wrote few months ago to the developer of itertools which told me that it was a minor speedup (if you want speed you will not use Python).
( 2013-06-03 04:16:46 +0200 )edit
answered 2013-05-20 16:25:42 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
Locally disable the preparser with the suffix r
It's not really disabling the preparser (the input is still preparsed), but telling the preparser not to process some of the (numerical) input by marking this input as raw (by appending the letter r).
sage: type(12)
<type 'sage.rings.integer.Integer'>
sage: type(12r)
<type 'int'>
sage: type(42.42)
<type 'sage.rings.real_mpfr.RealLiteral'>
sage: type(42.42r)
<type 'float'>
Also works for Python complex numbers:
sage: type(1j)
<type 'sage.rings.complex_number.ComplexNumber'>
sage: type(1jr)
<type 'complex'>
It's a bit similar to specifying some strings as raw by prepending an r to '...' or "..." or '''...''' or """..."""; for instance in '\t' the backslash-t produces a tab, but in r'\t' it stays backslash-t.
more
The function sage_input (sometimes) alows to get the Sage code to reconstruct an object you like.
sage: m = random_matrix(ZZ,3)
sage: m
[-1 1 -1]
[-2 -2 -1]
[ 1 -5 0]
I like that one, how could i reconstruct it ?
sage: sage_input(m)
matrix(ZZ, [[-1, 1, -1], [-2, -2, -1], [1, -5, 0]])
sage: m == eval(str(sage_input(m)))
True
Another example:
sage: e = m.eigenvalues()[0]
sage: sage_input(e)
R.<x> = QQbar[]
QQbar.polynomial_root(AA.common_polynomial(x^3 + 3*x^2 + 8), CIF(RIF(-RR(3.6128878647175449), -RR(3.6128878647175444)), RIF(RR(0))))
sage: sage_input(e, preparse=False)
R = QQbar['x']
x = R.gen()
QQbar.polynomial_root(AA.common_polynomial(x**3 + 3*x**2 + 8), CIF(RIF(-RR(3.6128878647175449), -RR(3.6128878647175444)), RIF(RR(0))))
more
Sorry for not making this answer an anonymous wiki. In the recent versions of askbot, only one answer per user is allowed, so i had to trick by firts writing a comment, and then transform it into an answer, but that way i could not make it anonymous :(
( 2017-03-20 16:47:39 +0200 )edit
answered 2013-05-16 10:00:10 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
To know whether Sage is running from the notebook or the command line, use the misc.embedded() function:
sage: misc.embedded()
False
more
answered 2013-04-29 01:11:50 +0200
This post is a wiki. Anyone with karma >750 is welcome to improve it.
Symbolic variables can be created from the command line as follows, faster than typing out var('x y z'):
,var x y z
more
Please start posting anonymously - your entry will be published after you log in or create a new account.
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http://research.omicsgroup.org/index.php/Cluster_chemistry
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Cluster chemistry
In chemistry, a cluster is an ensemble of bound atoms or molecules that is intermediate in size between a molecule and a bulk solid. Clusters exist of diverse stoichiometries and nuclearities. For example, carbon and boron atoms form fullerene and borane clusters, respectively. Transition metals and main group elements form especially robust clusters.[1] Clusters can also consist solely of a certain kind of molecules, such as water clusters.
The phrase cluster was coined by F.A. Cotton in the early 1960s to refer to compounds containing metal–metal bonds. In another definition a cluster compound contains a group of two or more metal atoms where direct and substantial metal metal bonding is present.[2] The prefixed terms "nuclear" and "metallic" are used and imply different meanings. For example, polynuclear refers to a cluster with more than one metal atom, regardless of the elemental identities. Heteronuclear refers to a cluster with at least two different metal elements.
The main cluster types are "naked" clusters (without stabilizing ligands) and those with ligands. For transition metal clusters, typical stabilizing ligands include carbon monoxide, halides, isocyanides, alkenes, and hydrides. For main group elements, typical clusters are stabilized by hydride ligands.
Transition metal clusters are frequently composed of refractory metal atoms. In general metal centers with extended d-orbitals form stable clusters because of favorable overlap of valence orbitals. Thus, metals with a low oxidation state for the later metals and mid-oxidation states for the early metals tend to form stable clusters. Polynuclear metal carbonyls are generally found in late transition metals with low formal oxidation states. The polyhedral skeletal electron pair theory or Wade's electron counting rules predict trends in the stability and structures of many metal clusters. Jemmis mno rules have provided additional insight into the relative stability of metal clusters.
History and classification
The development of cluster chemistry occurred contemporaneously along several independent lines, which are roughly classified in the following sections. The first synthetic metal cluster was probably calomel, which was known in India already in the 12th century. The existence of a mercury to mercury bond in this compound was established in the beginning of the 20th century.
Atomic clusters
Atomic clusters can be either pure, formed from a single atomic species, or mixed, formed from a mixed atomic species. Classifications criteria:
• by predominant bond nature: metallic, covalent, ionic;
• by atomic count: "micro" < 20, "small" < 100 < "large"
• by electric / magnetic properties
For the majority of atomic species there are clusters of certain atomic counts (so-called "magic numbers") that have preponderent representation in the mass spectra, an indication of their greater stability with respect to dissociation when compared to their neighboring atomic counts.
Molecular clusters
Atomic and molecular clusters are aggregates of 5-105 atomic or molecular units. They are classified according to the forces holding them together:
• Van der Waals clusters - attraction between induced electric dipoles and repulsion between electron cores of closed electronic configurations
• Metallic clusters - long range valence electron sharing (over many successive adjacent atoms) and partially directional
• Ionic clusters - valence electrons are almost entirely transferred among closest neighbors to yield 2 net, equal but opposite, electric charge distributions that mutually attract.
Quantum many-body mechanisms are also important.
The role of cluster formation in the precipitation of liquid mixtures and in the condensation, adsorption to surface or solidification phase transitions has long been investigated from a theoretical standpoint.
Cluster system properties — stem both from their size and composition (which contributes to the binding force types) that determine:
• the number of dimensions of their phase space
• the ranges of accessible positions and velocities of their atomic components
A gradual transition occurs between the properties of the molecular species and those of the corresponding bulk mix. And yet the clusters exhibit physical and chemical properties specific only to their configuration space (in turn strongly atom-count-dependent) and not specific to their bulk counterparts.
Cluster systems are metastable with respect to at least one of the following evolution classes:
• atom elimination or adsorption at cluster surface as a cause for their disassociation or growth
• configuration switches among a set of stable structures (a.k.a. an "isomer class") accessible to all clusters of a same atom count and a same relative component composition.
Many of their properties are due to the fact that a large fraction of their component atoms is found at their surface. With increasing size, the relative number of atoms at the cluster surface will scale approximately as N−1/3. One has to reach beyond a variable threshold of 9-27 component molecules (depending on the strength of the inter-molecular forces) to find global minimum configurations that hold at least one interior molecule. At the other end of the scale a cluster of about 105 atoms will expose only about 10% of the atoms at its surface, a still significant percentage in comparison to the bulk solid.
Transition metal carbonyl clusters
The development of metal carbonyl clusters such as Ni(CO)4 and Fe(CO)5 led quickly to the isolation of Fe2(CO)9 and Fe3(CO)12. Rundle and Dahl discovered that Mn2(CO)10 featured an "unsupported" Mn-Mn bond, thereby verifying the ability of metals to bond to one another in molecules. In the 1970s, Paolo Chini demonstrated that very large clusters could be prepared from the platinum metals, one example being [Rh13(CO)24H3]2-. This area of cluster chemistry has benefited from single-crystal X-ray diffraction.
Transition metal organic carbon (organometallic) clusters
There are also organometallic clusters. These clusters contain metal-metal bonds as well as at least a single organic moiety directly bonded to a metal atom (an organic ligand). One of the first examples of this type of clusters is a tricobalt nonacarbonyl cluster (its structure was determined by Dahl). This cluster contains a methyl carbyne ligand (CCH3) bonded to three cobalt atoms: [Co3(CCH3)(CO)9].[3] There are also more derivatives of the tricobalt methyl carbyne cluster where other organic ligands than methyl carbyne are introduced into the cluster structure (mainly by the work of Seyferth et al.).[4][5] The above-mentioned cluster serves as an example of an overall zero-charged (neutral) cluster. In addition, cationic (positively charged) rather than neutral organometallic trimolybdenum[6][7] or tritungsten[8] clusters are also known. The first representative of these ionic organometallic clusters is [Mo3(CCH3)2(O2CCH3)6(H2O)3]2+ (first prepared and characterized by Bino). The former tricobalt clusters are soluble in non-polar solvents, whereas the latter trimolybdenum and tritungsten ones are soluble in polar solvents including water.
Transition metal halide clusters
Linus Pauling showed that "MoCl2" consisted of Mo6 octahedra. F. Albert Cotton established that "ReCl3" in fact features subunits of the cluster Re3Cl9, which could be converted to a host of adducts without breaking the Re-Re bonds. Because this compound is diamagnetic and not paramagnetic the rhenium bonds are double bonds and not single bonds. In the solid state further bridging occurs between neighbours and when this compound is dissolved in hydrochloric acid a Re3Cl123− complex forms. An example of a tetranuclear complex is hexadecamethoxytetratungsten W4(OCH3)12 with tungsten single bonds and molybdenum chloride ((Mo6Cl8)Cl4) is a hexanuclear molybdenum compound and an example of an octahedral cluster. A related group of clusters with the general formula MxMo6X8 such as PbMo6S8 form a Chevrel phase, which exhibit superconductivity at low temperatures. The eclipsed structure of potassium octachlorodirhenate(III), K2Re2Cl8 was explained by invoking Quadruple bonding. This discovery led to a broad range of derivatives including di-tungsten tetra(hpp), the current (2007) record holder low ionization energy.
Boron hydrides
Contemporaneously with the development of metal cluster compounds, numerous boron hydrides were discovered by Alfred Stock and his successors who popularized the use of vacuum-lines for the manipulation of these often volatile, air-sensitive materials. Clusters of boron are boranes such as pentaborane and decaborane. Composite clusters containing CH and BH vertices are carboranes.
File:Dodecaborane-3D-balls.png
B12H122− is a famous boron hydride cluster
Fe-S clusters in biology
In the 1970s, ferredoxin was demonstrated to contain Fe4S4 clusters and later nitrogenase was shown to contain a distinctive MoFe7S9 active site.[9] The Fe-S clusters mainly serve as redox cofactors, but some have a catalytic function. In the area of bioinorganic chemistry, a variety of Fe-S clusters have also been identified that have CO as ligands.
Zintl clusters
Zintl compounds feature naked anionic clusters that are generated by reduction of heavy main group p elements, mostly metals or semimetals, with alkali metals, often as a solution in anhydrous liquid ammonia or ethylenediamine.[10] Examples of Zintl anions are [Bi3]3−, [Sn9]4−, [Pb9]4−, and [Sb7]3−.[10] Although these species are called "naked clusters," they are usually strongly associated with alkali metal cations. Some examples have been isolated using cryptate complexes of the alkali metal cation, e.g., [Pb10]2− anion, which features a capped square antiprismatic shape.[11] According to Wade's rules (2n+2) the number of cluster electrons is 22 and therefore a closo cluster. The compound is prepared from oxidation of K4Pb9 [12] by Au+ in PPh3AuCl (by reaction of tetrachloroauric acid and triphenylphosphine) in ethylene diamine with 2.2.2-crypt. This type of cluster was already known as is the endohedral Ni@Pb102− (the cage contains one nickel atom). The icosahedral tin cluster Sn122− or stannaspherene anion is another closed shell structure observed (but not isolated) with photoelectron spectroscopy.[13][14] With an internal diameter of 6.1 Angstrom it is of comparable size to fullerene and should be capable of containing small atoms in the same manner as endohedral fullerenes and indeed exists a Sn12 cluster that contains an Ir atom: [Ir@Sn12]3−.[15]
Metalloid clusters
Elementoid clusters are ligand-stabilized clusters of metal atoms that possess more direct element-element than element-ligand contacts. Examples of structurally characterized clusters feature ligand stabilized cores of Al77, Ga84, and Pd145.[16]
Intermetalloid clusters
These clusters consist of at least two different (semi)metallic elements and possess more direct metal-metal than metal-ligand contacts. The suffix "oid" designate that such clusters possess at a molecular scale, atom arrangements that appear in bulk intermetallic compounds with high coordination numbers of the atoms such as for example in Laves phase and Hume-Rothery phases.[17] Ligand-free intermetalloid clusters include also endohedrally filled Zintl clusters.[10][18] A synonym for ligand-stabilized intermetalloid clusters is "molecular alloy". The clusters appear as discrete units in intermetallic compounds separated from each other by electropositive atoms such as [Sn@Cu12@Sn20]12−,[17] as soluble ions [As@Ni12@As20]3−[10] or as ligand-stabilized molecules such as [Mo(ZnCH3)9(ZnCp*)3].[19]
Gas-phase clusters and fullerenes
Unstable clusters can also be observed in the gas-phase by means of mass spectrometry even though they may be thermodynamically unstable and aggregate easily upon condensation. Such naked clusters, i.e. those that are not stabilized by ligands, are often produced by laser induced evaporation - or ablation - of a bulk metal or metal-containing compound. Typically, this approach produces a broad distribution of size distributions. Their electronic structures can be interrogated by techniques such as photoelectron spectroscopy, while infrared multiphoton dissociation spectroscopy is more probing the clusters geometry.[20] Their properties (Reactivity, Ionization potential, HOMOLUMO-gap) often show a pronounced size dependence. Examples of such clusters are certain aluminium clusters as superatoms and certain gold clusters. Certain metal clusters are considered to exhibit metal aromaticity. In some cases, the results of laser ablation experiments are translated to isolated compounds, and the premier cases are the clusters of carbon called the fullerenes, notably clusters with the formula C60, C70, and C84. The fullerene sphere can be filled with small molecules, forming Endohedral fullerenes.
Extended metal atom chains
Extended metal atom chain complexes (EMAC) are a novel topic in academic research. An EMAC is composed of linear chains of metal atoms stabilized with ligands. EMACs are known based on nickel (with 9 atoms), chromium and cobalt (7 atoms) and ruthenium (5 atoms). In theory it should be possible to obtain infinite one-dimensional molecules and research is oriented towards this goal. In one study [21] an EMAC was obtained that consisted of 9 chromium atoms in a linear array with 4 ligands (based on an oligo pyridine) wrapped around it. In it the chromium chain contains 4 quadruple bonds.
Metal clusters in catalysis
Although few metal carbonyl clusters are catalytically useful, naturally occurring Iron-sulfur proteins catalyse a variety of transformations such as the stereo-specific isomerization of citrate to isocitrate via cis-aconitate, as required by the tricarboxylic acid cycle. Nitrogen is reduced to ammonia at an Fe-Mo-S cluster at the heart of the enzyme nitrogenase. CO is oxidized to CO2 by the Fe-Ni-S cluster carbon monoxide dehydrogenase. Hydrogenases rely on Fe2 and NiFe clusters.[22] Isoprenoid biosynthesis, at least in certain organisms, requires Fe-S clusters.[23]
Catalysis by metal carbonyl clusters
Metal carbonyl cluster compounds have been evaluated as catalysts for a wide range of reactions, especially for conversions of carbon monoxide.[24] No industrial applications exist however. The clusters Ru3(CO)12 and Ir4(CO)12 catalyze the Water gas shift reaction, also catalyzed by iron oxide, and Rh6(CO)16 catalyzes the conversion of carbon monoxide into hydrocarbons, reminiscent of the Fischer-Tropsch process, also catalyzed by simple iron compounds.
Some define cluster catalysis to include clusters that have only one active site on one metal atom. The definition can be further relaxed to include clusters that remain intact during at least one reaction step, and can be fragmented in all others.[25]
Metal carbonyl clusters have several properties that suggest that they may prove as useful catalysts. The absence of large bulk phases leads to a high surface-to-volume ratio, which is advantageous in any catalyst application as this maximizes the reaction rate per unit amount of catalyst material, which also minimizes cost.[26] Although surface metal sites in heterogeneous catalysts are coordinatively unsaturated, most synthetic clusters are not. In general, as the number of atoms in a metal particle decrease, their coordination number decreases, and significantly so in particles having less than 100 atoms.[27] This is illustrated by the figure at right, which shows dispersion (ratio of undercoordinated surface atoms to total atoms) versus number of metal atoms per particle for ideal icosahedral metal clusters.
Stereodynamics of clusters
Metal clusters are sometimes characterized by a high degree of fluxionality of surface ligands and adsorbates associated with a low energy barrier to rearrangement of these species on the surface.[28][29] The rearrangement of ligands on a cluster exterior is indirectly related to the diffusion of adsorbates on solid metal surfaces. Interconversion ligands between terminal, double-, and triply bridging sites is often facile. It has further been found that metal atoms themselves can easily migrate in or break their bonds with the cluster structure.[30][27]
Appendix: examples of reactions catalysed by transition metal carbonyl clusters
Although metal carbonyl clusters are rarely used, they have been subjected to many studies aimed at demonstrating their reactivity. Some of these examples include the following
Reaction Core Metals Catalyst Reference
Alkene hydroformylation Mo-Rh Mo2RhCp3(CO)5 [31]
Alkene hydroformylation Rh Rh4(CO)10+x(PPh3)2-x (x=0,2) [32]
CO hydrogenation Ru-Os H2RuOs3(CO)13 [31]
CO hydrogenation Ru-Co RuCo2(CO)11 [31]
CO hydrogenation Ir Ir4(CO)12 [30][32][33]
CO hydrogenation Fe Fe3(CO)12 [34]
Alkene hydrogenation Os-Ni H3Os3NiCp(CO)9 [31]
Alkene hydrogenation Ni Ni2+xCp2+x(CO)2 (x=0,1) [32]
Alkyne hydrogenation Os-Ni Os3Ni3Cp3(CO)9 [31]
Hydrogenation of aromatics Ni Ni2+xCp2+x(CO)2 (x=0,1) [32]
Acetaldehyde hydrogenation Ni Ni4(Me3CNC)7 [32]
Alkene isomerization V-Cr VCrCp3(CO)3 [31]
Hydrocarbon isomerization Fe-Pt Fe2Pt(CO)6(NO)2(Me3CNC)2 [31]
Butane hydrogenolysis Rh-Ir Rh3+xIr3-x(CO)16 (x=0,1,2) [31]
Methanol hydrocarbonylation Ru-Co Ru2Co2(CO)13 [31]
Hydrodesulfurization Mo-Fe Mo2Fe2S2Cp2(CO)8 [31]
CO and CO2 methanation Ru-Co HRuCo3(CO)12 [31]
Ammonia synthesis Ru-Ni H3Ru3NiCp(CO)9 [31]
Fischer-Tropsch catalysis
Species that are typical ligands for a metal cluster represent obvious reactant-catalyst combinations.[25][28] For example, hydrogenation of CO (Fischer-Tropsch synthesis) can be catalyzed using several metal clusters, as shown in the table above. It has been proposed that coordination of CO to multiple metal sites weakens the triple-bond enough to allow hydrogenation.[30] As in the industrially significant heterogeneous process, Fischer-Tropsch synthesis by clusters yields alkanes, alkenes, and various oxygenates. The selectivity is heavily influenced by the particular cluster used. For example, Ir4(CO)12 produces methanol, whereas Ru2Rh(CO)12 produces ethylene glycol.[30] Selectivity is determined by several factors, including steric and electronic effects. Steric effects are the most important consideration in many cases, however electronic effects dominate in hydrogenation reactions where one adsorbate (hydrogen) is relatively small.[25]
The cyclooligomerization of thiotanes illustrates the influence of steric effects on selectivity.[25] The selectivity ratio S3(CH2)9/S6(CH2)18 is 6.0 for Os4(CO)12 and 1.5 for W(CO)6, rationalized by greater steric effects in the Os cluster, leading to a preference for the smaller ring product.
In some cases, a metal cluster must be "activated" for catalysis by substitution of one or more ligands, such as acetonitrile.[35] For example, Os3(CO)12 will have one active site after thermolysis and the dissociation of a single carbonyl group. Os3(CO)10(CH3CN)2 will have two active sites.[25]
Computational studies
Computational studies have progressed from sum-of-energies calculations (incorporating Hückel theory-type approximations) to density functional theory (DFT). An example of the former is empirical packing energy calculations, where only interactions between adjacent atoms are considered. The packing potential energy can be expressed as follows:
$E=\Sigma_i\Sigma_j(Ae^{-Br_{ij}}-Cr_{ij}-\frac{q_iq_j}{r_{ij}^{-1}})$
where index i refers to all atoms of a reference molecule in the cluster lattice and index j refers to atoms in surrounding molecules according to crystal symmetry, and A, B, and C are parameters.[29] The advantage of such methods is ease of computation, however accuracy is dependent on the particular assumptions made. DFT has been used more recently to study a wide variety of properties of metal clusters.[36][37][38] Its advantages are being a first-principles approach without need of parameters and the ability to study clusters without ligands of a definitive size. However the fundamental form of the energy functional is only approximately known, and unlike other methods there is no hierarchy of approximations which allow a systematic optimization of results.[38]
Tight bonding molecular dynamics has been used to study bond lengths, bond energies, and magnetic properties of metal clusters, however this method is less effective for clusters with less than 10-20 metal atoms due to a larger influence of approximation errors for small clusters.[39] There are limitations on the other extreme as well that exist with any computation method, that the approach to bulk-like properties is difficult to capture because at these cluster sizes the cluster model becomes increasingly complex.
References
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12. ^ itself made by heating elemental potassium and lead at 350°C
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14. ^ Li-Feng Cui, Xin Huang, Lei-Ming Wang, Dmitry Yu. Zubarev, Alexander I. Boldyrev, Jun Li, and Lai-Sheng Wang (2006). "Sn122−: Stannaspherene". J. Am. Chem. Soc. (COMMUNICATION) 128 (26): 8390–8391. PMID 16802791. doi:10.1021/ja062052f.
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16. ^ A. Schnepf, H. Schnöckel (2002). "Metalloid aluminum and gallium clusters: element modifications on the molecular scale?". Angewandte Chemie International Edition 114: 1793–1798. doi:10.1002/1521-3773(20021004)41:19<3532::AID-ANIE3532>3.0.CO;2-4.
17. ^ a b S. Stegmaier, T. F. Fässler (2011). "A Bronze Matryoshka – The Discrete Intermetalloid Cluster [Sn@Cu12@Sn20]12− in the Ternary Phases A12Cu12Sn21 (A = Na, K)". J. Am. Chem. Soc. 133: 19758–19768. doi:10.1021/ja205934p.
18. ^ T. F. Fässler, S. D. Hoffmann (2004). "Endohedral Zintl Ions: Intermetalloid Clusters". Angewandte Chemie International Edition 116: 6400–6406. doi:10.1002/anie.200460427.
19. ^ R. A. Fischer et al. (2008). "Twelve One-Electron Ligands Coordinating One Metal Center: Structure and Bonding of [Mo(ZnCH3)9(ZnCp*)3]". Angewandte Chemie International Edition 47: 9150–9154. doi:10.1002/anie.200802811.
20. ^ Fielicke A, Kirilyuk A, Ratsch A, Behler J, Scheffler M, von Helden G, Meijer G (2004). "Structure determination of isolated metal clusters via far-infrared spectroscopy". Phys. Rev. Lett. 93 (2): 023401. Bibcode:2004PhRvL..93b3401F. PMID 15323913. doi:10.1103/PhysRevLett.93.023401.
21. ^ Rayyat H. Ismayilov, Wen-Zhen Wang, Rui-Ren Wang, Chen-Yu Yeh, Gene-Hsiang Lee and Shie-Ming Peng (2007). "Four quadruple metal–metal bonds lined up: linear nonachromium(II) metal string complexes". Chem. Commun. (11): 1121–1123. PMID 17347712. doi:10.1039/b614597c.
22. ^ Bioorganometallics: Biomolecules, Labeling, Medicine; Jaouen, G., Ed. Wiley-VCH: Weinheim, 2006.3-527-30990-X.
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30. ^ a b c d <Douglas, Bodie; Darl McDaniel; John Alexander (1994). Concepts and Models of Inorganic Chemistry (third ed.). New York: John Wiley & Sons, Inc. pp. 816–887. ISBN 0-471-62978-2.
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32. Smith, A; Basset, J (3 February 1977). "Transition metal cluster complexes as catalysts. A review". Journal of Molecular Catalysis 2 (4): 229–241. doi:10.1016/0304-5102(77)85011-6.
33. ^ Ichikawa, M; Rao, L; Kimura, T; Fukuoka, A (17 January 1990). "Transition Heterogenized bimetallic clusters: their structures and bifunctional catalysis". Journal of Molecular Catalysis 62 (1): 15–35. doi:10.1016/0304-5102(90)85236-B.
34. ^ Hugues, F; Bussiere, P; Basset, J; Commereuc, D; Chauvin, Y; Bonneviot, L; Olivier, D (1981). "Catalysis by supported clusters: Chemisorption, decomposition and catalytic properties in Fischer-Tropsch synthesis of Fe3(CO)12, [HFe3(CO)11]- (and Fe(CO)5) supported on highly divided oxides". Studies in Surface Science and Catalysis 7 (1): 418–431. doi:10.1016/S0167-2991(09)60288-3.
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37. ^ Ma, Q999; Xie, Z; Wang, J; Liu, Y; Li, Y (4 January 2007). "Structures, binding energies and magnetic moments of small iron clusters: A study based on all-electron DFT". Solid State Communications 142 (1-2): 114–119. Bibcode:2007SSCom.142..114M. doi:10.1016/j.ssc.2006.12.023.
38. ^ a b Pacchioni, G; Kruger, S; Rosch, N (1999). Electronic structure of naked, ligated, and supported transition metal clusters from 'first principles' density functional theory. New York: Wiley-VCH. pp. 1392–1433. ISBN 3-527-29549-6.
39. ^ Andriotis, A; Lathiotakis, N; Menon, M (4 June 1996). "Magnetic properties of Ni and Fe clusters". Chemical Physics Letters 260 (1-2): 15–20. Bibcode:1996CPL...260...15A. doi:10.1016/0009-2614(96)00850-0.
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Faculté des sciences
## Magnetohydrodynamic pumping in nuclear magnetic resonance environments
### In: Sensors and Actuators B: Chemical, 2007, vol. 123, no. 1, p. 636-646
We present a DC magnetohydrodynamic (MHD) pump as component of a nuclear magnetic resonance (NMR) microfluidic chip. This is the first time that MHD pumping in an NMR environment was observed and demonstrated. This chip generates a maximum flow rate of 1.5 μL min−1 (2.8 mm s−1 in the microchannel) for an applied voltage of 19 V with only 38 mW of power consumption in a... Plus
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Summary
We present a DC magnetohydrodynamic (MHD) pump as component of a nuclear magnetic resonance (NMR) microfluidic chip. This is the first time that MHD pumping in an NMR environment was observed and demonstrated. This chip generates a maximum flow rate of 1.5 μL min−1 (2.8 mm s−1 in the microchannel) for an applied voltage of 19 V with only 38 mW of power consumption in a 7 T superconductive magnet. We developed a simple method of flow rate measurement inside the bulky NMR magnet by monitoring the displacement of a liquid–liquid interface of two immiscible liquids in an off-chip capillary. We compared and validated this flow measurement technique with another established technique for microfluidics based on the displacement of microbeads. This allowed us to characterize and compare the flow rate generated by the micropump on top of a permanent magnet (B1 = 0.33 T) with the superconductive magnet (B0 = 7.05 T). We observed a 21-fold increase in flow rate corresponding to the ratio of the magnetic field intensities (B0/B1 = 21) in accordance with the theoretical flow dependence on the magnetic field intensity. The final aim is to integrate MHD pumps together with planar coils in a microfluidic system for NMR analysis. The high performance of MHD pumps at relatively low flow rates is seen as an asset for NMR and MRI applications.
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http://devmaster.net/forums/topic/10632-help-with-simple-directsound-c-app/page__p__57754
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# Help with simple DirectSound c++ app
7 replies to this topic
### #1CNewb
New Member
• Members
• 4 posts
Posted 27 November 2008 - 09:31 PM
Hello,
I am using Visual Studio Express 2008 to try and generate a tone.
I have got as far as setting up the DirectSound object and creating the buffer, but don't know where to go from there. I don't want to play a .wav file at the moment, just generate a tone.
Here is the code so far:
#include "stdafx.h"
#include <string>
#include <iostream>
#include <Dsound.h>
#define _USE_MATH_DEFINES
#define _WIN32_DCOM
#include <cmath>
using namespace std;
HWND hwnd;
HRESULT hr;
LPDIRECTSOUNDBUFFER lpdsbuffer;
LPVOID lpvWrite;
DWORD dwLength;
LPDIRECTSOUND lpds;
WAVEFORMATEX wf;
DSBUFFERDESC dsbdesc;
int main()
{
CoInitialize(NULL);
//Create DirectSound object...
if ( FAILED ( DirectSoundCreate ( NULL , &lpds , NULL ) ) ) return 2;
//Get console window handle, feed it to the SetCooperativeLevel function
SetConsoleTitle( ( LPCWSTR ) L"Title" );
hwnd = FindWindow( NULL, ( LPCWSTR ) L"Title" );
if ( FAILED ( lpds->SetCooperativeLevel( hwnd , DSSCL_NORMAL ) ) ) return 8;
//Setup buffer...
memset ( &dsbdesc, 0, sizeof ( DSBUFFERDESC ) );
dsbdesc.dwSize = sizeof ( DSBUFFERDESC );
dsbdesc.dwFlags = DSBCAPS_PRIMARYBUFFER;
dsbdesc.dwBufferBytes = 0; //must be 0 for primary buffer
dsbdesc.lpwfxFormat = NULL; //must be null for primary buffer
//Wave format...
memset ( &wf, 0, sizeof ( WAVEFORMATEX ) );
wf.wFormatTag = WAVE_FORMAT_PCM;
wf.nChannels = 2;
wf.nSamplesPerSec = 44100;
wf.wBitsPerSample = 16;
wf.nBlockAlign = 4;
wf.nAvgBytesPerSec = 176400;
//Create buffer...
if ( FAILED ( lpds->CreateSoundBuffer( &dsbdesc , &lpdsbuffer , NULL ) ) return 3;
//Set buffer WaveFormat...
lpdsbuffer->SetFormat ( &wf );
//------------------------------------------------
system("PAUSE");
return 0;
}
What do I need to do next to get a simple buzzing noise to play?
How would I vary the frequency of the tone on the fly?
### #2Reedbeta
DevMaster Staff
• 5305 posts
• LocationBellevue, WA
Posted 27 November 2008 - 10:55 PM
First of all, if you just want to generate a simple tone, I would go ahead and set wf.nChannels to 1. That way, it will be mono and you won't have to worry about the extra complication of stereo (not that stereo is very complicated).
Second, in DirectSound you can't play sounds directly with the primary buffer, so you'll need to construct a secondary buffer. You will write data into the secondary buffer and then instruct DirectSound to play it. Actually it can be useful to have two secondary buffers so you can generate sound into one while playing the other. But this might not be necessary for your application.
As for generating a sound, you'll need to use a sine wave. Something like this:
#include <cmath>
...
short * pBuffer; // the locked secondary buffer to generate into
int bufferLength; // number of samples in buffer
...
float frequency = 440.0f; // frequency in Hz. 440 = concert A.
float volume = 0.5f; // volume as fraction of the maximum possible volume
for (int i = 0; i < bufferLength; ++i)
{
// calculate sine wave
float time = i / 44100.0f; // calculate time in seconds
float wave = volume * sinf(2 * M_PI * time * frequency);
// convert it to a short to store in the sound buffer
pBuffer[i] = static_cast<short>(wave * 32768.0f);
}
This should produce a tone you can hear when the buffer plays. You can alter the frequency and volume simply by changing the appropriate variables and regenerating the buffer.
You can also experiment with different shapes of waves, e.g. using a square, triangle, or sawtooth wave instead of a sine, to see what effect it has on the sound. Also, you can experiment with adding sines of different frequencies together.
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### #3CNewb
New Member
• Members
• 4 posts
Posted 28 November 2008 - 04:15 PM
Okay, this is the code so far (I basically copied and pasted it from another thread on this forum). It plays a tone.
#include "stdafx.h"
#include <dsound.h>
#define _USE_MATH_DEFINES
#define _WIN32_DCOM
#include <cmath>
#include <string>
#include <iostream>
#include <time.h>
using namespace std;
LPDIRECTSOUND8 lpds;
LPDIRECTSOUNDBUFFER lpdsbuffer;
WAVEFORMATEX wfx;
DSBUFFERDESC dsbdesc;
HWND hwnd;
short* buffer = new short[ 44100 * 2 ];
bool playing = false;
int SampleRate = 44100;
//*************************
//
//*************************
HWND GetConsoleHwnd( void )
{
SetConsoleTitle( ( LPCWSTR ) L"Title" );
hwnd = FindWindow( NULL, ( LPCWSTR ) L"Title" );
return(hwnd);
}
//*************************
//
//*************************
HRESULT createSoundObject( void )
{
HRESULT hr;
hr = DirectSoundCreate8( NULL , &lpds , NULL );
hr = CoInitializeEx( NULL , 0 );
hr = lpds->SetCooperativeLevel( hwnd , DSSCL_NORMAL );
return hr;
}
//*************************
//
//*************************
WAVEFORMATEX setWaveFormat( void )
{
WAVEFORMATEX wfx;
memset( &wfx, 0, sizeof( WAVEFORMATEX ) );
wfx.wFormatTag = WAVE_FORMAT_PCM;
wfx.nChannels = 2;
wfx.wBitsPerSample = 16;
wfx.nSamplesPerSec = SampleRate; //44100
wfx.nBlockAlign = 4;
wfx.nAvgBytesPerSec = SampleRate * 4;
return wfx;
}
//*************************
//
//*************************
DSBUFFERDESC setBufferDescription()
{
DSBUFFERDESC dsbdesc;
memset( &dsbdesc, 0, sizeof ( DSBUFFERDESC ) );
dsbdesc.dwSize = sizeof ( DSBUFFERDESC );
dsbdesc.dwFlags = DSBCAPS_CTRLPOSITIONNOTIFY | DSBCAPS_GETCURRENTPOSITION2;
dsbdesc.dwBufferBytes = 1024;
dsbdesc.lpwfxFormat = &wfx;//<- Set wave format
return dsbdesc;
}
//*************************
//
//*************************
HRESULT createSecondarySoundBuffer( void )
{
HRESULT hr = lpds->CreateSoundBuffer( &dsbdesc , &lpdsbuffer , NULL );
return hr;
}
//*************************
//
//*************************
HRESULT fillSoundBuffer( bool first )
{
bool firsthalf = first;
LPVOID lpvWrite;
DWORD dwLength;
HRESULT hr = lpdsbuffer->Lock( 0 , dsbdesc.dwBufferBytes , &lpvWrite , &dwLength , NULL , NULL , DSBLOCK_ENTIREBUFFER );
if ( SUCCEEDED ( hr ) )
{
memcpy( lpvWrite , buffer , dwLength );
hr = lpdsbuffer->Unlock( lpvWrite , dwLength , NULL , NULL );
}
return hr;
}
//*************************
//
//*************************
BOOL fillBufferWithWaveForm( string form ){
if( form == "sine" )
{
short* ptr = buffer;
unsigned short i;
float amp = 1.0f;
float tmp;
short output;
for( i=0 ; i < 44100 ; i++ )
{
tmp = amp * sinf(100.0f * 2.0f * M_PI * ( ( float ) i / 44100.0f ) );
output = ( short )( tmp*32767 );
ptr[0] = output;
ptr[1] = output;
ptr += 2;
}
return true;
}
}
//*************************
//
//*************************
void SetupSound()
{
HRESULT hr;
BOOL formFound = false;
string waveform = "sine";
// Rename the ConsoleWindow and retrieve its
// handle by looking up its new name in Windows
hwnd = GetConsoleHwnd();
// Create the Basic LPDIRECTSOUND8 object
hr = createSoundObject();
// Set the default wave format (hard coded)
wfx = setWaveFormat();
// Set the default buffer description (hard coded)
dsbdesc = setBufferDescription();
// Create the secondary sound buffer
hr = createSecondarySoundBuffer();
// Generate a waveform and put it into the playback array
formFound = fillBufferWithWaveForm(waveform);
// fill the secondary sound buffer entirely with the playback array data
hr = fillSoundBuffer( true );
// Start playback at position 0 and loop this sound until explicitely stopped
lpdsbuffer->SetCurrentPosition( 0 );
//DSBPLAY_DEFAULT
//DSBPLAY_LOOPING
}
//*************************
//
//*************************
int _tmain( int argc , char* argv[] )
{
SetupSound();
lpdsbuffer->Play( 0 , 0 , DSBPLAY_LOOPING );
lpdsbuffer->SetFrequency(1300);//<---- not working!!!
system("PAUSE");
lpdsbuffer->Release();
lpds->Release();
return 0;
}
However I can't seem to get the frequency to change by calling lpdsbuffer->SetFrequency(). Is this some bug with DirectSound?
### #4Reedbeta
DevMaster Staff
• 5305 posts
• LocationBellevue, WA
Posted 28 November 2008 - 07:07 PM
SetFrequency() is intended to change the sample rate with which the buffer is played back. In your case, SetFrequency(44100) would play it at the original frequency at which the wave is generated; SetFrequency(88200) would play it at twice the frequency, etc.
There are limits on how much you can change the frequency using this method. You should look at this page to see how to find the limits.
In any case, it's better to change the frequency by regenerating the buffer rather than using SetFrequency. See my previous post for details.
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### #5CNewb
New Member
• Members
• 4 posts
Posted 29 November 2008 - 09:37 PM
I can't get SetFrequency to do anything at all. Incrementing the data fed into the buffer with a for-next loop doesn't produce a smooth transition.
### #6Reedbeta
DevMaster Staff
• 5305 posts
• LocationBellevue, WA
Posted 29 November 2008 - 10:20 PM
What do you mean by "does something strange"?
Varying the frequency really is quite simple, you just need to slow down and take the time to look for bugs and figure out *why* something doesn't work rather than abandoning it and trying something completely different.
Now, let's forget about SetFrequency for the moment and just focus on generating sine waves ourselves. If you look at the code you posted, the "fillBufferWithWaveForm" function is doing almost exactly what the code I posted does, only the frequency is a constant 100.0f.
So, how about you start with the code you posted, make sure it works and you can run it and hear the sound (it should be a very low note), then just change that 100.0f to a 200.0f and run it again. You should hear a higher note (an octave higher to be precise).
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### #7CNewb
New Member
• Members
• 4 posts
Posted 29 November 2008 - 10:25 PM
I am currently using and was refering to your code. It does work, but not as I expected.
The reason why I need SetFrequency is that when I try something like:
lpdsbuffer->Play( 0 , 0 , DSBPLAY_LOOPING );
for ( int i=0 ; i < 500 ; i++ )
{
Sleep(1);
frequency += 5;
formFound = fillBufferWithWaveForm(waveform);
hr = fillSoundBuffer( true );
}
There is not the smooth transition between frequencies which I imagine the DirectSound code would provide.
### #8Reedbeta
DevMaster Staff
• 5305 posts
• LocationBellevue, WA
Posted 29 November 2008 - 10:53 PM
Okay. The problem with the smooth transition is something that can be dealt with.
I think the problem is likely that when you change frequencies, the end of the sine wave from one frequency doesn't match the beginning of the sine wave from the next frequency. There is a sudden jump in the amplitude, which can result in a clicking or popping sound as the frequency changes.
To solve this you'll have to do two things. First of all, you'll need to use two secondary buffers, and "ping-pong" between them - that is, set them up so they are played one after the other, and continuously write data into the one that is not playing. The reason for this is that if you have just one buffer, you have to overwrite it while it's playing (as you're currently doing), and with no idea where the "play head" is, there's no way to make the ends of the two sines match up. I don't know exactly how to set up the two buffers this way in DirectSound, but I presume it lets you set up a callback function to be called when it finishes with a buffer.
The second thing you have to do use use a phase accumulator, a global variable that tracks the phase of the sine and allows it to be maintained across buffers and across frequency changes. Your FillBuffer function would then look something like this:
float phase = 0; // global variable
...
for (int i = 0; i < bufferLength; ++i)
{
// calculate sine wave
float wave = volume * sinf(phase);
phase += 2 * M_PI / 44100.0f * frequency;
// convert it to a short to store in the sound buffer
pBuffer[i] = static_cast<short>(wave * 32768.0f);
}
This way the phase will stay continuous despite any changes in frequency.
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https://infoscience.epfl.ch/record/210244/
|
## System fidelity factor evaluation of wearable ultra-wideband antennas for on-body communications
This study reports an experimental study of the system fidelity factor (SFF) of ultra-wideband wireless body area network antennas in an on-body environment. This study also investigates the influence in the SFF because of the antenna polarisation with respect to the body. For this purpose, two antennas having different polarisations are compared: a mono-cone antenna with the polarisation perpendicular to the wearer and a printed monopole with the polarisation either parallel or perpendicular to the wearer. A phantom made of pork meat was considered as a model for the wearer's body, and five different communication scenarios involving each pair of antennas were considered. On-body experimental results show that the time-domain behaviour of the transmission is better for two different antenna types having the same polarisation, but, more importantly, that the SFF (and thus the time-domain fidelity of the signal) is better for a link having a polarisation perpendicular to the body.
Published in:
Microwaves Antennas & Propagation, IET, 9, 10, 1054-1058
Year:
2015
Publisher:
Hertford, Inst Engineering Technology-Iet
Laboratories:
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http://mail-archives.apache.org/mod_mbox/db-derby-user/200504.mbox/%[email protected]%3E
|
# db-derby-user mailing list archives
##### Site index · List index
Message view
Top
From David Van Couvering <[email protected]>
Subject Re: Problems with building Derby
Date Thu, 07 Apr 2005 13:11:17 GMT
Yes, I got this problem too, and it took me most of a day to figure it
out.
Are you on XP? If so, make sure in your ant.properties file you escape
the colons and the backslashes, e.g. C\:\\my\\directory\\to\\files
That said, this has worked for others, but it didn't do squat for me.
What I finally had to do was to move (or copy) the JDK 1.4 and JDK 1.3
folders to <derby_root>/jdk141 and <derby_root>/jdk141. After much
painful inspecting of the build scripts I determined this was the
default location the scripts were using and no matter how hard I tried I
couldn't get the scripts to listen to me and look elsewhere.
Once I did this the build worked like a charm.
David
Arunanthisivam Vimalathithen wrote:
> Hi,
>
> I seem to be having problems building Derby. I am getting the error
> "java.lang not found in classpath or bootclassPath" I looked around the
> archive and tried different versions of servlet.jars as indicated there,
> but still there was no success.
>
> I also tried it with the developer\trunk branch which comes with
> geronimo-spec-servlet-2.4-rc4.jar and other related jars, but the same
> problem persists. Where am I going wrong?. If it is related to a
> different version of servlet.jar could someone point me where I can get
> the corect version.
>
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http://math.stackexchange.com/questions/309506/symbol-for-such-that-not-in-set
|
Symbol for “such that” (not in set)
If $A$ is a set, we can use the set notation
$$A= \{ b \mid\text{property p_1 of b}\}$$
But say $A$ is an element like $b$,
$$A = b \mid \text{property p_1 of b}$$
is this a usual notation? I am trying to say that $A$ is a $b$ that such that( $\mid$ ) it satisfies property $p_1$ of $b$, and assume that exactly one $b$ satisfies property $p_1$.
Otherwise, is there a more usual convention to express this?
-
Usually you would just say that $A$ possesses property $p_1$, or that $p_1(A)$ holds. – MJD Feb 20 '13 at 21:31
You could replace the $=$ in the first equation by an $\in$ to make $A$ an element instead of a set. – TMM Feb 20 '13 at 21:32
The usual notation is "such that". Also note that if one writes "let $A$ be a foo such that bar" then foo should be predicative and not a variable, i.e. please don't write "let $A$ be a $b$ such that $p_1(b)$", instead write e.g. "let $A$ be a positive integer such that $p_1(A)$". – Hagen von Eitzen Feb 20 '13 at 21:32
The point being that $b$ is completely unnecessary in the second form. You could write that simply as "Assume $A$ is s.t. $p_1(A)$." – Thomas Andrews Feb 20 '13 at 21:56
"Such that" is occasionally denoted by \ni = $\,\ni\,$, e.g., in lecture, to save time, as a shortcut. Others, when writing in lectures or taking notes, and again, to save time, use "s.t.".
But in writing anything to submit (homework, publication), when possible, it is best to just write the words "such that".
In sets though, like set-builder notation, both $\mid$ and $:$ are used:
$$\{x \in \mathbb R \mid x < 0\}$$ $$\{x \in \mathbb R : x \lt 0\}$$
"The set of all $x \in \mathbb R$ such that $x \lt 0$.
-
This notation $\ni$ for "such that" was introduced by Peano, see here. – Math Gems Feb 20 '13 at 21:45
$\ni$ usually stands for $\in$ when you are writing in Hebrew and can't foresee the amount of spacing you will need for writing left-to-right in mid-text. :-) – Asaf Karagila Feb 20 '13 at 21:46
Yes, I think you're correct, @Math Gems! Peano it was. – amWhy Feb 20 '13 at 21:48
+1 for simply writing "such that". – Douglas S. Stones Feb 20 '13 at 21:56
Of course, the very text label, "\ni", indicates the alternative meaning for $\ni$, name, $X\ni x$ being a synonym for $x\in X$. That duplicate meaning is one reason it is not used much as "s.t." – Thomas Andrews Feb 20 '13 at 21:58
$\{ g \in G : \Phi(g) \}$ is the set of those $g$ in $G$ if $\Phi$ is true. I also see $:$ for such that in piecewise functions a lot, like $$f(x)=\left\{\begin{array}{lcl}1&:&a\in B \\ 2 &:& a \notin B\end{array}\right.$$ which reads the same way. $\{g | g \in G\}$ first gives the form of stuff that you want, then "such that" g is in wherever.
So, grammatically it seems like what you say would make sense. I have never seen it used like that though. Personally, I like to use $\ni$, which is a (somewhat outdated) alternative such that symbol. (Actually this is not exactly how it's written, as a backwards $\in$. It should be thinner and taller, like a longbow. I can't find a typesetting which works on MSE's TeX though.) The modern way to do it is to use either $|$ or $:$ in sets and mathematical expressions, but just write it out if you're anywhere else. If you must abbreviate it, write $\text{s.t}$.
-
Exemplify the answer of the problem is the best way(+1) – Babak S. Jul 5 '13 at 6:39
$f(x)=\left\{\begin{array}{lcl}1&:&a\in B \\ 2 &:& a \notin B\end{array}\right.$ can mean $f(x)=\left\{\begin{array}{lcl}\frac{1}{a}\in B \\ \frac{2}{a} \notin B\end{array}\right.$ Also, $\{g | g \in G\}$ can mean that the (always true if $g\in\mathbb Z_{\neq 0}$) statement $g | g$ belongs to the set $G$. Even the $\ni$ symbol can be ambiguous at times (meaning "contains"). – user26486 Sep 2 '14 at 19:59
@mathh I've never seen $1:a$ meaning $\frac{1}{a}$. Can you show me an example where that is used in the literature? – Alexander Gruber Sep 3 '14 at 2:16
@AlexanderGruber See here. "In some non-English-speaking cultures, "a divided by b" is written a : b." I have never seen "a ÷ b" being used in my country and have only seen "a : b" instead. – user26486 Sep 3 '14 at 5:51
@mathh Very interesting. Which country is that? – Alexander Gruber Sep 3 '14 at 13:37
I had actually asked my prof about this a couple weeks ago... the symbol he gave is $\ni$. So, for an existential quantifier, we have:
$$\exists \,\,x\in\mathbb{R}\ni x^2 =x$$
He said we wouldn't use it in the class, as he thought it looked not so great...
This can also be seen here: http://www.physicsforums.com/showthread.php?t=195398
I, personally, like just abbreviating it "s.t." in my notes, as it's shorter, but more clear.
-
That backwards epsilon notation looks terrible. I learned it a while ago and always thought it is ugly. It would be nice if it died off. Writing "s.t." is pretty simple as an alternative. – KCd Feb 20 '13 at 21:39
I agree that in writing mathematical English one can use $\ni$ or 's.t.' but in the case you cite, I would prefer $$\left(\exists \,\,x\in\mathbb{R}\right) \left[x^2 =x\right]$$ exactly as in set notation or predicate calculus. The such that is built into the quantifier. – Barbara Osofsky Feb 20 '13 at 21:55
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https://www.eevblog.com/forum/rf-microwave/hallicrafter-s38b-restoration-the-saga/msg3087460/
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### Author Topic: Hallicrafter S38B restoration: the saga (Read 775 times)
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#### worsthorse
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##### Hallicrafter S38B restoration: the saga
« on: May 30, 2020, 06:42:58 pm »
I am not much of a boat anchor guy but I really like the pre-jetsons space agey look of some of the broadcast and communications receivers from the mid-fifties. Combine that with too much free time for looking at ebay and this happens:
This is Hallicrafter's take on the All American Five, a four band AM/CW receiver with a band spread control and requiring an external antenna called the S38B (I think there were five versions of this radio, all based on the same design). It was manufactured between 1947 and 1953. I am going to learn how to restore old radios by restoring an old radio, I guess.
Here's what it looks like inside:
A lot of dirt and grease up top. A little less underneath. I did a brief power up test and, of course, it didn't work. Probably one or more bad tubes, the filaments of which are wired in series. After doing a little research, here are the first things I am going to do:
Inspect for damage and mods made by previous owners,
Replace the existing wax paper and electrolytic caps,
Clean the chassis, top and bottom,
Install an isolation transformer and fuse (more on this later).
After doing the inspection, I found minor damage to the speaker cone (which I can repair) and no obvious mods or rework other than the lamp wiring replacement, so I set about cleaning the chassis. Here's what it looks like after four or five hours of degreasing and removing corrosion, etc. The tools of choice: simple green, a mild degreasing solvent, brass-x, toothbrushes and a pile of cloth rags.
The smear on the chassis is from varnish left behind when someone scraped a label off the chassis. It was removed after this photo. Next up, recapping...
The bottom after the recapping:
The S38B, like all the AA5 radios, was heavily cost-engineered to the point of being dangerous (hence the isolation transformer...) with the result that the physical placement of components and wiring markedly effects the radio's performance. When replacing components ignore matching lead length and component placement at your peril. I did not.
While I wait for replacement vacuum tubes to arrive, I am going to install the isolation transformer and see if figure out how the circuit actually works. I haven't tried to decipher a tube-based circuit in, I dunno, forty years?
specialization is for insects.
#### bob91343
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #1 on: May 30, 2020, 06:57:49 pm »
I appreciate and commend your efforts. Having said that, I am amazed at the great popularity of these cheap radios. The S-38 series had to be the worst possible short wave radio. The original S-38 had six tubes, including the BFO that they eliminated later in favor of making the IF amplifier oscillate. They made all user accessible surfaces of nonconducting material to justify the transformerless design, and had to struggle a bit to connect an antenna and headphones but they found a way.
I recall, even in my youth, reading the Hallicrafters motto 'the radio that amazes the experts' and thinking yeah sure, amazed that anyone would try to sell something with such poor performance.
Yet they are still in use and those who use them like them. I once owned one but was quick to sell it. The later versions changed design to a slide rule dial style. Lafayette imitated the appearance with a somewhat better radio. And National imitated it with the SW-54.
I never felt that an uncalibrated bandspread dial was of any value. In those days, hams hated dials with strings and preferred gears.
Because I am so old, I remember many of these units and have played with them. I formulated opinions which have stood the test of time.
#### worsthorse
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #2 on: May 30, 2020, 10:16:34 pm »
I appreciate and commend your efforts. Having said that, I am amazed at the great popularity of these cheap radios. The S-38 series had to be the worst possible short wave radio. The original S-38 had six tubes, including the BFO that they eliminated later in favor of making the IF amplifier oscillate. They made all user accessible surfaces of nonconducting material to justify the transformerless design, and had to struggle a bit to connect an antenna and headphones but they found a way.
I recall, even in my youth, reading the Hallicrafters motto 'the radio that amazes the experts' and thinking yeah sure, amazed that anyone would try to sell something with such poor performance.
Yet they are still in use and those who use them like them. I once owned one but was quick to sell it. The later versions changed design to a slide rule dial style. Lafayette imitated the appearance with a somewhat better radio. And National imitated it with the SW-54.
I never felt that an uncalibrated bandspread dial was of any value. In those days, hams hated dials with strings and preferred gears.
Because I am so old, I remember many of these units and have played with them. I formulated opinions which have stood the test of time.
*laugh* No argument with anything you said. I am fairly certain that the S38B is not going to replace my FT1000D or even any of the single band CW only rigs I own, like the QCX, in my shack. That said, it is kind of cool looking and works okay for casual SWL which is all I expected. And given the circuit simplicity and construction, it is a good introductory restoration project. If I get it working I will set it up in my office next to the equally anachronistic Numechron Tymetor desk clock.
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#### worsthorse
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #3 on: May 30, 2020, 10:55:35 pm »
Installing the isolation transformer and a fuse. First why...
In the cost-savings derby, power supplies and transformers just aren't going to fly. The S38B used a series string of filaments, powered by the AC line instead. That means it has an unpolarized plug, which allows the chassis to be hot even if the switch is in the off position. The fix was to isolate the chassis from the case, which is better than nothing and still not very good, from a safety perspective. Here's the schematic:
I broke the connection at the power input and inserted a 35VA isolation transformer and fuse:
This is the only place the transformer will fit. Caution required, because the speaker is right above it and mis-placement means the case won't fit...
Isolation transformers are a topic of much animated discussion. My only concern is safety. My only worry is if adding one will cause problems because there's no earth ground connection...
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#### retrolefty
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #4 on: May 30, 2020, 11:42:59 pm »
We seem to have followed similar paths. My first SW/Ham receiver was a Hallicrafter SX-110 in the 60s, looked really great but performed poorly. Spent many years trying out others receivers and stopped collecting with a Drake R-4A. Now that is a nice looking receiver, great tuning feel. and nice performance. Now they buy a little SDR module dongle and your receiver is a video game on your PC. Blah. However the waterfall display sure looks useful.
« Last Edit: May 30, 2020, 11:45:33 pm by retrolefty »
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#### bob91343
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #5 on: May 31, 2020, 04:01:26 am »
We seem to be in accord here. My current transceiver is a TS-940S with TS-440S backup. Those old tube radios couldn't hold a candle to these 'modern' units (mine are from the 1980s).
There isn't much SWL fodder these days. Foreign BC seems to have died for the most part.
The isolation transformer is a good idea and, since you have gone that far, you can defeat the grounding isolation in the radio and connect antenna and then ground the chassis. You may experience hum problems but those were endemic to the radio. They saved on a speaker by making it small and got the side benefit of it not responding well to hum frequencies.
#### worsthorse
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #11 on: June 12, 2020, 03:45:43 am »
I am guessing that you have been spending more time on this poorly designed radio than the original engineers did.
Well, maybe not poorly designed as much as designed to a poor \$pecification.
*laugh* perhaps. figuring out how stuff works and, when i can, making stuff that doesn't work so well work better is a lot of fun.
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#### worsthorse
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #12 on: June 30, 2020, 06:04:25 pm »
I was able to spend a few hours at the bench, working on the S38B. After testing the radio with and without the isolation transformer, it was clear that the isolation transformer wasn't making the hum problem worse. After looking at radios of this era that had a proper multi-tap transformer, which looked like this (from Elements of Radio Servicing):
I duplicated this with my isolation transformer, although with just one winding since the filament string uses line voltage. On the input side, I added a in-line fuse. The on/off switch is on the primary side, too. There is a 0.01mfd X2 capacitor across the primary side. This is in place to reduce modulation hum and it works better, or at least as well, as a 0.01mfd from one side of the AC line to ground. With these changes, I could keep the original two prong plug while making the radio safer to use.
After all that, the modulation hum is gone but there is still a low level hum that can be heard even in standby mode. There are, I think, two reasons for this. First, the radio design, which I can't really do much about. Second, I have power line noise here that shows up to a greater or lesser extent on every radio (no matter how expensive) around here. That being the case I am going to declare victory on this one.
On the outside, before re-assembling it, I cleaned the case, cleaned up the paint splatters, repaired a couple of dings in the paint, and cleaned the plastic window (carefully, it scratches ver easily). Now it looks like this, not quite brand new but not bad:
Here's the front
The back
And the inside, from the back
I spent the evening tuning around and listening to AM SW stations and, yes, CW on the amateur bands. As expected the amateur CW sub-band covers a very very small portion of the dial but the band spread actually works pretty well.
The weirdest thing was listening to FT8 signals on a radio built in 1953ish. I was briefly tempted to see if I could decode FT8 and decided not to torture myself with it.
Anyway, this one is done. At this point, reducing the hum further would require time and energy I want to invest in other projects.
specialization is for insects.
#### bob91343
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #13 on: June 30, 2020, 11:53:48 pm »
Good job! It looks great in the pics.
One thing gnaws at me, that you left the filament string on the primary side. At least that's what I think you did. The secondary side needs some sort of control so that its voltage doesn't drift to a dangerous level. The heater to cathode ratings of the tube need to be respected.
The hum is either due to a ground loop, a leaky heater to cathode, or insufficient filtering. Is it smooth 60Hz, or raspy open grid, or 60 Hz with harmonics from insufficient filtering?
You are wise to avoid attempting to decode FT8.
#### worsthorse
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #14 on: July 01, 2020, 12:27:36 am »
The filament string is on the secondary of the isolation transformer as expected. Sorry for the confusion.
It might be a ground loop somewhere that I missed. I have swapped the most likely suspect tubes with no change. I've also recapped it and added a filter cap on the primary side of the isolation transformer. It is a smooth hum and it is apparent when the radio is in standby mode. I could start looking around with an oscilloscope, which would be the next step, but I am going to let it go for now, though I may come back to it after I get a couple of other more pressing projects in hand.
It does look pretty good though, doesn't it?
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#### CaptDon
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #15 on: July 02, 2020, 11:41:11 pm »
I owned an S38B bought used from Jim Strauss K3JFL at
J.R.S. Distributors in York Pa. I wanted to listen to Icelandic
broadcasts on 15.770mhz and my Kenwood twins R599/T599
did not have those SWL bands included I did extensive mods
to the S38 including huge filter caps (1000uf@200vdc), replaced
all coupling caps and cathode caps and did a 'peak' alignment
which may have made it a bit more narrow banded but slightly
more sensitive. The weather, moon phase and time of year
hugely effected the signal strength. Signal hops at that frequency
tend to have 1200 mile intervals and I was at about 2800 miles
a bit beyond the second hop but I loved to listen on that radio.
It had a much better speaker put in and had a great AM SWL
sound to it. My girl at the time was from Iceland and spoke also
Danish and German and she loved that little radio listening to
Danish, Norwegian and German broadcasts. The KW Twins were
Ham Only bands so she liked to play with the S38.
Senior Master Captain for Victorian Princess
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#### bob91343
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##### Re: Hallicrafter S38B restoration: the saga
« Reply #16 on: July 03, 2020, 12:36:47 am »
A smooth low pitched hum is likely pure 60 Hz. It may be magnetic coupling from the transformer to the voice coil or output transformer. When in standby, what's still energized (besides the heaters)?
Smf
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https://www.aanda.org/articles/aa/full_html/2013/03/aa19282-12/aa19282-12.html
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Free Access
Issue A&A Volume 551, March 2013 A76 15 Interstellar and circumstellar matter https://doi.org/10.1051/0004-6361/201219282 25 February 2013
## 1. Introduction
The post-asymptotic giant branch (AGB) star HR 4049 is a single-lined spectroscopic binary, surrounded by a circumbinary disk rich in dust and gas. The secondary star has not been detected at any wavelength, but its presence is inferred from the radial-velocity variations of the primary. HR 4049 is a remarkable object in several respects. First, it is the prototype of a group of evolved binaries in which the primary star has an extremely metal-depleted photosphere ([Fe/H] = −4.8 dex, Van Winckel et al.1995). The photospheric abundance pattern resembles that of the interstellar medium, where chemical elements with high condensation temperatures have formed dust grains and are underabundant in the gas phase. Mathis & Lamers (1992) and Waters et al. (1992) have proposed a scenario to explain the selective depletion in these post-AGB binaries. A fraction of the mass lost by the primary star during its AGB phase is captured in a stable circumbinary disk. The process of disk formation around post-AGB stars is not well understood, but binarity is a necessary condition (Van Winckel 2003; Gielen et al. 2008). When the disk has formed and the strong AGB wind has ceased, gas in the disk can be re-accreted from the disk onto the primary star. Dust grains, however, experience radiation pressure and are prevented from falling in. Since refractive elements easily condense into dust grains, the accreted gas is chemically peculiar, which gives rise to the observed photospheric abundance pattern. The photosphere of HR 4049, therefore, became extremely depleted in iron. The selective re-accretion hypothesis thus holds the promise of a high abundance of iron-rich dust in the circumbinary environment.
Second, HR 4049 has a peculiar infrared spectrum. The infrared excess is large (LIR/L = 1/3, Dominik et al. 2003). The spectrum, shown in Fig. 1, displays strong features of polycyclic aromatic hydrocarbon molecules (PAHs) and even diamond emission bands, which indicates the presence of carbon-rich material in the system (Geballe et al. 1989; Guillois et al. 1999). Recently, the detection of Buckminsterfullerene (C60) was reported (Roberts et al. 2012). The strong gaseous emission lines of H2O, OH, CO, and CO2, on the other hand, point to oxygen-rich gas-phase chemistry (Cami & Yamamura 2001; Hinkle et al. 2007). The rest of the spectrum is featureless. In particular, the 10-μm silicate emission feature, which is common in disks around evolved binaries (Gielen et al. 2008), is absent. The spectrum has a shape that closely matches that of a 1200 K blackbody. Dominik et al. (2003) propose two models to fit the spectral energy distribution: the emission is produced by large (≫1 μm) grains, or the disk is very optically thick. The authors favor the second option. In this paper, we will propose another alternative: the emission is produced by (small) dust grains with a smooth opacity curve.
Fig. 1Infrared spectrum of HR 4049 (black: ISO-SWS, blue: Spitzer-IRS). The prominent features between 6 and 13 μm are caused by PAHs. The band between 4 and 5.3 μm is the result of a forest of CO, OH, and H2O molecular emission lines (Hinkle et al. 2007). Emission lines of CO2 are visible longward of 13 μm (Cami & Yamamura 2001). Open with DEXTER
Furthermore, HR 4049 is an attractive observational target. The circumbinary disk is viewed at a large inclination angle, close to edge-on. Waelkens et al. (1991) have published Geneva optical photometry of HR 4049. The Geneva photometric system comprises seven bands, U,B1,B,B2,V1,V, and G, with effective wavelengths ranging from 346 nm to 581 nm1. Waelkens et al. (1991) found that the target is variable in all seven filters. The largest-amplitude variability is synchronous with the 430-day orbital period of the binary and ascribed to variable extinction in the line of sight towards the primary star by matter in the circumbinary disk. Due to its orbital motion, the primary hides behind the inner rim of the disk at phases of minimal brightness, when it is closest to the observer, and returns to maximal brightness roughly half an orbit later. The Geneva color–magnitude diagrams of HR 4049 contain information on the material that attenuates the primary star. Waelkens et al. (1991) show that the observed extinction law is roughly consistent with interstellar extinction, although notable differences are present.
In this paper we attempt to identify the dust species which produces the featureless infrared spectrum of HR 4049. We search for the dominant source of opacity in the circumbinary disk at optical-to-infrared wavelengths. We will show that the combination of infrared spectroscopy with spatially resolved observations is a powerful tool to discern between dust species with featureless opacities. The method described in this paper can potentially be applied to solve other astronomical questions, such as the iron-to-carbon dust content of winds around AGB stars.
## 2. Observations and data reduction
### 2.1. Interferometry
Interferometric measurements of HR 4049 were obtained within the Belgian Guaranteed Time on the European Southern Observatory’s (ESO) Very Large Telescope Interferometer (VLTI) Sub-Array (VISA). We made observations in the near-infrared H and K bands on nine baseline triangles with AMBER (Petrov et al. 2007) in the low spectral-resolution mode (LR-HK). Medium-resolution AMBER observations were obtained on four baseline triangles; two centered around 2.1 μm (MR–2.1) and two around 2.3 μm (MR-2.3). When the weather conditions allowed, the AMBER observations were obtained with the aid of the fringe tracker FINITO. This instrument uses 70% of the H-band flux to stabilize the fringes on the AMBER detector. Mid-infrared interferometry of HR 4049 was obtained with MIDI (Leinert et al. 2003) in the HIGH-SENS prism mode (HSP) on two baselines. The observing log is shown in Table 1. The corresponding spatial-frequency coverage is shown in Fig. 2. The interferometric observations were made at binary orbital phases φ ∈ [0,0.2], where φ = 0 corresponds to periastron passage. This is around the photometric minimum of the primary star in the optical (φ = 0.13, Bakker et al. 1998).
Table 1
Log of the AMBER and MIDI interferometric observations.
#### 2.1.1. AMBER data reduction
The AMBER data were reduced using the data processing software amdlib version 3 (Tatulli et al. 2007; Chelli et al. 2009). The calibrator star is HD 91964, a K4/K5 III giant with a stellar diameter of 1.27 mas (Mérand et al. 2005). For both science target and calibrator, the 25% fringe measurements with the highest signal-to-noise were selected to compute and calibrate the squared visibilities. The data are of very good quality and an increase in the percentage of selected frames does not significantly alter the outcome of the reduction procedure. For the closure phases, 90% of the best frames were selected. The closure phase was estimated by adding phasors in the complex plane (Tatulli et al. 2007). The closure phase of the science target was calibrated by subtracting the measured closure phase of the calibrator.
Fig. 2Spatial-frequency coverage of the interferometric measurements. Black dots refer to AMBER data, red dots to MIDI data. Open with DEXTER
#### 2.1.2. MIDI data reduction
The MIDI data reduction was performed using the MIA+EWS package2. Despite the fact that HR 4049 is a rather faint target for VISA+MIDI, the signal-to-noise of the correlated-flux (CF) measurements is high (~25). The total flux (F) is disentangled from the strong mid-infrared sky background by chopping to an off-target position on the sky and subtracting the on- and off-target spectra. For faint targets this leads to noisy spectra. This technique is not employed to determine the correlated flux. The background in the two interferometric channels is uncorrelated, while the interferometric signals are in phase opposition. Subtraction of both channels effectively removes the background while maintaining the correlated flux (see MIDI manual3). This results in correlated-flux spectra with much better signal-to-noise than the total-flux spectrum. Because HR 4049 is a faint target, F could not be measured reliably and we cannot compute the calibrated visibility (V) (1)Here, the indices sci and cal refer to the uncalibrated measurements of science target and calibrator. However, the ratio of the visibilities at two given baselines is equal to the ratio of the calibrated correlated fluxes (2)where the indices refer to baselines 1 and 2. We cannot determine the absolute visibilities V15 m and V29 m because of the low-quality total spectrum, but the ratio of the visibilities at the two baselines V29 m/V15 m can be recovered from the observations. We will use the latter quantity in our analysis and refer to it as the MIDI relative visibility.
### 2.2. Archival observations
The analysis presented here also makes use of archival observations of HR 4049. For the optical analysis, we have used the Geneva photometry published by Waelkens et al. (1991). Optical spectroscopy of HR 4049 indicates Teff = 7500 K, log g = 1 dex, and an iron depletion of [Fe/H] = −4.8 dex for the primary star, while the secondary is undetected (Lambert et al. 1988; Waelkens et al. 1991; Van Winckel et al. 1995; Bakker et al. 1996). A fit to the optical photometry with a Kurucz (1993) model with these parameters yields a stellar angular diameter of 0.45 ± 0.03 mas. The interstellar reddening towards the binary was determined to be E(B − V) = 0.17 mag from fits to the data at photometric maximum. We used the interstellar extinction law of Cardelli et al. (1989) with RV = 3.1.
Two infrared spectra of HR 4049 have been obtained with the Short-Wavelength Spectrograph (SWS, de Graauw et al. 1996) aboard the Infrared Space Observatory (ISO, Kessler et al. 1996). We use the spectrum that was taken on 6 May 1996 at an orbital phase φ = 0.04, which is within the orbital-phase range covered by the interferometric observations. We downloaded the highly processed data products (HPDP) from the ISO archive in the reduction of Frieswijk et al.4. These authors started from data products produced with the off-line processing pipeline version 10.1. The Infrared Spectrograph (IRS, Houck et al. 2004) aboard the Spitzer Space Telescope (Werner et al. 2004) has also obtained a spectrum of HR 4049 in the short-high (SH) mode. We reduced the spectrum with pipeline version S15.3.0. It is reassuring that this spectrum, albeit obtained with a different instrument on a different satellite, is very similar to the ISO-SWS spectrum, both in shape and in absolute flux level. We show both infrared spectra in Fig. 1.
Ground-based mid-infrared observations of HR 4049 were obtained with VLT/VISIR (Lagage et al. 2004) mounted on UT3. The VISIR data were retrieved from the ESO data archive5. Images were obtained in one broad-band and three narrow-band photometric filters: SiC (λcen = 11.85 μm, Δλ = 2.34 μm), PAH2 (λcen = 11.25 μm, Δλ = 0.59 μm), PAH2_2 (λcen = 11.88 μm, Δλ = 0.37 μm), and Q1 (λcen = 17.65 μm, Δλ = 0.83 μm). The filter at 11.25 μm is centered on the PAH 11.3 μm feature. The PAH flux contribution in this band, estimated from the ISO-SWS spectrum, is 25%. The other two narrow-band filters (at 11.88 and 17.65 μm) capture almost no PAH emission. The PAH flux contribution in the broad-band filter at 11.85 μm is 5%. VISIR also obtained spectroscopy of HR 4049 in the N band. Due to the poor quality of the calibrator measurements, we could not extract a calibrated VISIR spectrum. However, VISIR is a slit spectrograph. The spatial information in the direction of the slit (north-south in this case) is therefore preserved. We performed astrometry on the spectral order in the raw 2D CCD images of HR 4049. This yields the spatial extent (full width at half maximum, FWHM) and relative photocenter position of the target at each wavelength. We discuss the VISIR data in Sect. 4.
The Hipparcos parallax of HR 4049 is 1.23 ± 0.36 mas, which places the object at a distance of 800 pc (Van Leeuwen 2007). Remarkably, Hipparcos did not flag HR 4049 as a binary. The spectroscopically determined semi-major axis of the primary orbit is asini = 0.60 ± 0.01 AU (Bakker et al. 1998). If the object is at a distance of 800 pc, the photocenter displacement of the primary on the sky due to the binary orbit is at least 0.75 mas, of the same order of magnitude as the measured parallax. In fact, this is true for any distance to the source; the dimensions of the binary are similar to the major axis of Earth’s orbit around the Sun. Although not detected by Hipparcos, the binarity of HR 4049 must have influenced the parallax measurement. We will come back to this issue and solve it in Sect. 6.
## 3. Optical extinction
### 3.1. The dust model
We re-analysed the Geneva photometry published by Waelkens et al. (1991). We tested which dust species can produce the observed extinction law towards the primary star. To this end, we computed opacities, i.e., mass absorption and scattering coefficients κ, for a set of common astronomical dust species in the JENA database (Jäger et al. 1994, 1998; Dorschner et al. 1995; Henning et al. 1995; Henning & Stognienko 1996; Scott & Duley 1996). We selected the species for which refractive indices are available from UV to infrared wavelengths, covering at least 0.2–100 μm. Because of the remarkably featureless infrared spectrum of HR 4049, we also focused on the dust species which have smooth infrared opacities. This excludes a priori small crystalline silicates, for example.
To convert optical constants to absorption and scattering opacities, a dust grain size and morphology needs to be assumed. Here, we tested a range of grain sizes covering 0.01 μm to 10 μm, and three grain shape models: solid spherical particles (Mie grains), a distribution of hollow spheres (DHS), and a continuous distribution of ellipsoids (CDE). The DHS model assumes that grains are spherical, but may include a large volume fraction of vacuum, mimicking grain porosity. We varied the maximum vacuum fraction between fmax = 0 (i.e., Mie grains) and fmax = 0.8. The CDE model assumes a distribution of ellipsoidal grains, ranging from spheres to needles. Opacities are computed in the Rayleigh limit, i.e., for grains with sizes a that obey 2πa/λ ≪ 1, with λ the wavelength. Because the computed opacities are used here at optical wavelengths, the CDE model is only valid for small grains with sizes below 0.1 μm. Both DHS and CDE are able to represent grain morphologies that deviate strongly from spherical (Min et al. 2003, 2005). Table 2 lists the dust species, adopted grain sizes, and shape distributions, for which absorption and scattering opacities were computed.
### 3.2. Extinction law
We reddened the Kurucz model atmosphere for the primary star according to the opacity curve of each of the dust species. We assumed isotropic scattering. The stellar light was attenuated by gradually increasing the dust column density until the maximal observed optical attenuation of AV ≈ 0.3 mag was reached. We then computed synthetic Geneva magnitudes and colors for the reddened atmosphere models. Because of the logarithmic magnitude scale, the synthetic color–magnitude diagrams are straight lines.
Table 2
Tested dust species, sizes, and shapes.
Fig. 3Six independent Geneva color–magnitude diagrams of HR 4049. The linear-regression fit to the data is shown in black. The other curves show the color/magnitudes of the Kurucz model, reddened with the interstellar extinction law of Cardelli et al. (1989, foreground extinction) and with different dust species with a grain size of 0.01 μm and an appropriate range of column densities (variable circumstellar extinction). The grain shape distribution is DHS with fmax = 0.8, except for amorphous carbon (Mie, i.e., DHS with fmax = 0). Top left panel: the discrepancy between the observed and the modeled U − B color may be due to a UV-excess in the binary system. Open with DEXTER
We turned back to the observations and performed a linear-regression fit to six independent color–magnitude diagrams of HR 4049: U − B, B1 − B, B2 − B, V1 − B, V − B, and G − B vs. V (Fig. 3). All other color–magnitude diagrams are linear combinations of these six and thus contain the same information. The residual scatter around the linear fit may have different causes, including intrinsic brightness variations of the primary star, activity in the binary system, density variations in the circumbinary dust that attenuates the primary starlight, and also observational uncertainties. We defined a chi-square variable (3)with di the perpendicular distance of a point in the color–magnitude diagram to the linear fit and ⟨ d ⟩ the average distance of the points to the line. The latter is zero because of the linear regression. An analoguous value was computed for the reddened atmosphere models. In the latter case, ⟨ d ⟩ is non-zero. An offset between the location of the linear fit to the model data and the photometric observations can occur because of differences between the modeled and the true spectrum of the target, or between the modeled and true interstellar extinction law. This is clear in the U − B vs. V color–magnitude diagram (Fig. 3, upper left panel). However, here we focused on the extinction law in the line of sight and hence only on the slope of the variations in the color–magnitude diagrams. We defined (4)A model with X2 = 1 provides a match to the slopes of the extinction curve equivalent to a linear regression fit, given the residual spread on the data.
Table 3
Dust species with extinction curves consistent with the Geneva color–magnitude diagrams (X2 < 3, see Eq. (4)).
Fig. 4a) ISO-SWS spectrum in the N-band range. The PAH features at 8.6, 11.3, 12.0, and 12.7 μm are indicated, the dashed line represents the continuum. b) Spatial extent along the slit north-south direction of VISIR. The dashed line indicates the width of the spatially unresolved continuum, which increases with wavelength. c) Relative spatial position with respect to the continuum along the slit direction of VISIR. The PAH emission region is extended on a scale of several 100 s of AU and its photocenter is located towards the south of the continuum emission region. Open with DEXTER
Because of the extreme iron depletion in the primary photosphere and the hypothetical selective re-accretion, one may expect that the circumbinary disk contains detectable amounts of iron-bearing dust. DHS-shaped iron oxides, magnetite, and metallic iron grains reproduce the observed extinction law reasonably well; however, 0.01 μm-sized Mie amorphous-carbon opacities provide the best fit. The fit with 0.01 μm-sized DHS-shaped (i.e., fmax > 0) amorphous carbon grains is also acceptable. A summary is presented in Table 3. We cannot unambiguously differentiate between these different dust species based on the optical extinction data alone. All other tested dust species, including amorphous silicates and Fe2O3, can be rejected (X2 ≫ 3). Grain sizes larger than 0.1 μm can be excluded as well, because the corresponding opacities are too grey to match the steep observed extinction law.
## 4. PAH emission
We now focus on the appearance of the system at infrared wavelengths. Menut et al. (2009) analyzed early MIDI observations of HR 4049. They find that the emission region of the PAH 7.7, 8.6, and 11.3 μm features is more extended than that of the underlying continuum. Our new MIDI measurements confirm this. The correlated fluxes show no sign of the PAH features. This indicates that the PAH emission region is fully resolved by the interferometer, even on the short baseline of 15 m. We estimated a lower limit to the extent of the PAH emission region of 100 mas (64 AU at 640 pc). In line with Menut et al. (2009), we conclude that the PAH emission region is not only situated in the disk, although a contribution from the disk is still possible.
We turn to the VISIR data to locate the PAH emission. In all four VISIR images, HR 4049 appears as a point source. Closer inspection of the point spread function (PSF), however, shows that it is 15% broader than the calibrator PSF in the photometric band that covers the PAH 11.3 μm feature, while both PSFs are almost identical in the broad-band filter. This indicates that the PAH emission region is slightly resolved on a scale comparable to that of the VISIR PSF, i.e., several 100 mas.
Confirmation comes from the VISIR slit spectroscopy. Figure 4 shows the mid-infrared ISO-SWS spectrum, the spatial extent (FWHM), and the relative spatial position of HR 4049 projected onto the slit direction (i.e., north-south) from VISIR. The PAH emission region is marginally, but convincingly, resolved with respect to the unresolved emission of the circumbinary disk. Moreover, the photocenter of the PAH emission region, projected onto the slit north-south direction, is located towards the south of the continuum emission region. The PAH emission is therefore not centered on HR 4049, consistent with the idea of a bipolar outflow in which the receding lobe (towards the north) is partially obscured by the circumbinary disk.
## 5. The circumbinary disk: an optically thick wall?
Fig. 5Spectral energy distribution of HR 4049. The ISO-SWS spectrum (grey line), and IRAS 25, 60, and 100 μm, and SCUBA 850 μm photometry (grey boxes). The green line is the fit with a single blackbody (1200 K, in accordance with Dominik et al. 2003). The spectral energy distribution of our model (blue) underestimates the flux at λ > 20 μm. The red line shows our model plus a 200 K blackbody, scaled to the SCUBA 850 μm flux. See Sect. 7 for details. Open with DEXTER
Based on the shape of the infrared spectral energy distribution (Fig. 5), Dominik et al. (2003) argue that the disk around HR 4049 is optically very thick. In their model, the disk is a vertical wall with a large scale height, 1/3 of the inner disk radius. We have compared this geometry to our interferometric observations.
Our wall model consists of a vertical wall of uniform brightness with an inner radius Rin ∈ [5,25] mas, a height H = Rin/3, an inclination i ∈ [40°,70°], and a disk position angle on the sky PA ∈ [0°,360°]. We define PA = 0° when the far side of the inclined disk, projected on the sky, is oriented towards the north6. Only the inside of the wall, which faces the binary, is bright. Because a high optical depth is assumed, the backside is dark and blocks the light from the inside. The flux contribution of the primary star at near-infrared wavelengths is estimated from the spectral energy distribution and the stellar atmosphere model. We construct wall model images and compute near-infrared visibilities and closure phases as explained in Appendices A and B.
The best wall models have PA = 130 ± 10°, i = 60 ± 10°, Rin> 15 mas, and reduced chi-square values of ~20 for the AMBER visibilities and ~8 for the AMBER closure phases. The wall model images have by definition very sharp edges and they deviate strongly from point symmetry because of the high inclination. As a result, the model closure phases have large amplitudes, which is inconsistent with the moderate closure phases observed. Nonetheless, the orientation of the disk on the sky is well established. Specifically, it is the progression of the zero points in the closure phase as a function of baseline position angle, well sampled by the observation sequence (c) to (g) listed in Table 1, that provides a strong constraint on the disk position angle.
The disk extent is less well determined; the simple geometric model provides only a lower limit to the inner radius of the wall. At long baselines, the circumbinary disk is almost fully resolved, while the primary star remains spatially unresolved. In other words, the measurements at long baselines provide only information on the wavelength-dependent flux ratio of the star and the disk in the near-infrared. As a reference, a basic model with an unresolved star (V = 1) surrounded by a fully resolved disk (Vdisk = 0) provides a fit to the AMBER visibilities with a reduced chi-square of ~40. The corresponding closure phases are obviously zero in this case, inconsistent with the observations.
Following the reasoning of Dominik et al. (2003, their Sect. 5), one obtains for the optically thick wall that (5)an equation that is valid irrespective of the distance to HR 4049. Dominik et al. (2003) derive T = 1200 K for a fit to the spectral energy distribution with a single blackbody, a value that we confirm here in Fig. 5. This temperature corresponds to Rin/R = 45. All our best wall models have Rin/R larger than 67 ± 4, using a stellar angular diameter of 0.45 mas (Sect. 2.2), and hence T < 1000 K. The assumption of an optically thick vertical wall producing blackbody emission is not consistent with the interferometric measurements. We therefore reject this hypothesis.
The presence of very small dust particles in the upper layers of the circumbinary disk is evidenced by the optical extinction towards the primary. We investigate an alternative model in which the featureless infrared spectrum is produced by small grains with smooth opacities. We present this new model in Sect. 7. First, however, we discuss the distance to HR 4049.
## 6. The distance to HR 4049
The distance to HR 4049 is highly uncertain because the Hipparcos parallax measurement is influenced by the binary motion. Strangely enough, Hipparcos did not recognize HR 4049 as a binary star and also a detailed inspection of the Hipparcos data did not reveal the binary signature (D. Pourbaix, priv. comm.). This means that, due to the specific combination of orbital parameters and the distance to HR 4049, the Hipparcos measurements resemble that of a single star at a distance of 800 pc.
The optical spectroscopy constrains all orbital parameters of the primary (epoch of periastron passage T0, period P, projected semi-major axis asini, eccentricity e, and argument of periastron ω; Bakker et al. 1998), apart from the longitude of the ascending node Ω and the inclination of the orbital plane i. The interferometric measurements, and specifically the closure phase measurements, constrain the orientation angle of the disk’s major axis on the sky. If the orbital plane of the binary coincides with the disk plane, this angle is equivalent to Ω. This assumption is justified: although the formation process of the disk is unknown, binary interaction is most likely a key ingredient and the plane of the disk is expected to be identical to the orbital plane.
The far side of the disk in the wall models presented in Sect. 5 is located at a position angle PA = 130° ± 10° E of N. The longitude of the ascending node Ω is either PA + 90° or PA − 90°, depending on the orbital direction of the binary: if the binary revolves counterclockwise in the plane of the sky, then Ω = 40°. Otherwise Ω is 220°. We have computed the apparent parallax of HR 4049, which is a combination of the binary orbit and the intrinsic, distance-related parallax, for Ω and i consistent with the results of the interferometric modeling and for any distance to the source d. To mimic the Hipparcos measurements, we have computed the offset of the primary on the sky at the times of the Hipparcos observations. An ellipse was fitted to these offsets to determine the simulated parallax.
We find that for Ω = 40°, the computed parallax agrees within uncertainties with the observed value of 1.23 ± 0.36 mas, if the distance to HR 4049 is 1050 ± 320 pc. In this case, the combination of the binary orbit and Earth’s orbit projected on the sky increases the parallax signal. Hence, the measured Hipparcos parallax appears larger than that expected for a single star at a distance of 1050 pc. For Ω = 220°, we find a distance of 640 ± 190 pc. In the latter case, the binary motion on the sky counteracts the distance-induced parallax and the target is closer than the combined parallax appears to suggest.
### 7.1. A priori considerations
The optical attenuation AV of the primary due to the circumbinary matter varies between 0 and 0.3 mag. The line of sight towards the primary intersects with the upper layers of the inner disk. The optical analysis indicates that the dust in this region is either iron-bearing dust or amorphous carbon. It also proves that very small (0.01 μm) grains are present and that these grains are the dominant source of opacity in the upper layers of the disk at optical wavelengths.
The goal of this paper is to identify the dust species which establishes the appearance of the HR 4049 system from optical to mid-infrared wavelengths. We stress that our investigation does not aim to determine the dust component that dominates the disk in terms of mass or abundance, but in opacity.
For this purpose, we use the radiative-transfer modeling code MCMax (Min et al. 2009). The code computes the temperature and density structure of a dust- and gas-rich disk around a central illuminating source. The detection of strong gaseous emission lines indicates that the circumbinary disk around HR 4049 is indeed rich in gas (Cami & Yamamura 2001; Hinkle et al. 2007). The dust provides the opacity and is heated by the star. The gas is assumed to be thermally coupled to the dust and thus has the same temperature structure. The prime assumption of the model is that the disk is in vertical hydrostatic equilibrium. The disk scale height is set by the balance between gas pressure and gravitational pull of the central object perpendicular to the disk midplane. In the case of HR 4049, the central source is a binary. The estimated semi-major axis of the binary is of the order of a few primary stellar radii (Bakker et al. 1998). It is clear from our simple geometric model presented above in Sect. 5, that the dimensions of the binary are much smaller than the dimensions of the disk. Therefore, we can approximate the binary by a single central star, which has the temperature and luminosity of the primary star of HR 4049, but with a stellar mass representing both stars.
Radiative-transfer modeling of circumstellar disks has shown that the smallest dust grains provide the bulk of the opacity, both in terms of absorption in the optical and thermal emission in the near- and mid-infrared, even when these grains represent only a tiny fraction of the total disk mass (e.g., Meijer et al. 2008; Acke et al. 2009). The appearance of the disk in the mid-infrared is almost exclusively dominated by this small-grain component, regardless of the presence of larger grains with lower opacities. A radiative-transfer model with a content of only small grains, or with a mixture of large and small grains, will produce similar spectra and images. Therefore, for the purpose of our investigation, it is viable to assume that the entire circumbinary dust disk fully consists of small grains. Furthermore, guided by our analysis of the attenuation of the stellar light by the disk at optical wavelengths, we assume the disk contains only one of the species mentioned above. The opacities of the four tested dust species are plotted in Fig. 6. As described in Sect. 6, the distance to HR 4049 is either 640 pc or 1050 pc. We computed radiative-transfer models for both distances.
A downside of our approach is that our model cannot produce a satisfying match to the spectral energy distribution at far-infrared and millimeter wavelengths. At long wavelengths, 0.01 μm-sized grains have no opacity and hence produce no emission. The inclusion of large dust grains in the model would significantly improve the match to the spectral energy distribution. However, this strongly increases the complexity of the model in terms of free parameters (e.g., grain size distribution, vertical settling and mixing) and is beyond the scope of this paper.
### 7.2. The model grid
Fig. 6Opacity curves of the four dust species that satisfy the optical extinction law towards HR 4049, normalized by κV (at 0.55 μm). The grain size is 0.01 μm, the grain shape distribution is either DHS with fmax = 0.8, or Mie (fmax = 0). Open with DEXTER
The computational time needed to calculate a single model is approximately 1 min. We opted for a grid approach instead of applying a minimization fitting routine. Each of the grid models is compared a posteriori to the available data (see Sect. 7.3). The free input parameters of the radiative-transfer model are limited to the following: the opacity table of the dust species under consideration, the total stellar mass of the binary (M ), the inner and outer radius of the disk (Rin, Rout), the total mass in the small dust grains (Mdust), and the surface density power law (6)where p is a free parameter and Σin is fixed by (7)The orientation of the disk in space is fixed by two angles: the inclination (i) and the position angle on the sky (PA). Again, we define PA = 0° when the far side of the inclined disk, projected on the sky, is oriented towards the north. The grid parameter ranges are summarized in Table 4.
Table 4
Grid parameters of the radiative-transfer models.
### 7.3. Comparing the models to the observations
In the search for the model in the grid which best reproduces the observations, we have defined five chi-square variables.
• . The modeled infrared spectrum is compared to the ISO-SWSspectrum of HR 4049 at wavelengths outside ofthe PAH features (see Fig. 7).
• and . From the model images at 2.2 μm, squared visibilities and closure phases are computed (see Appendices A and B). We compute a chi-square for both the squared visibilities and the closure phases . The latter is defined using phasors (8)\begin{lxirformule}$\Phi_{j}$\end{lxirformule} are the observed closure phases, σj the corresponding errors, Φmod,j the modeled closure phases, and N = 2152 the number of closure phase measurements.
• . From the image at 10 μm, model visibilities are computed. Because the MIDI data reduction only provides good estimates of the relative visibilities on the two baselines, we define a chi-square (9)Herein, Vrel,j = V29m,j/V15m,j are the MIDI relative visibilities, σrel,j the corresponding errors, Vrel,mod,j the model visibility ratios, and N = 30 the number of MIDI relative visibilities.
• . All interferometric observations were taken near the photometric minimum, when the primary of HR 4049 is most obscured. The optical attenuation at that phase is AV = 0.3 ± 0.1 mag. The attenuation of the model is computed by comparing the model spectrum to the input Kurucz model at 0.55 μm. Because the tested dust species are selected to provide a good fit to the extinction curve in the optical wavelength range, radiative-transfer models with the right optical attenuation have the right optical colors as well.
An acceptable model should provide a good fit to all observations simultaneously. First, we select models based on their ability to reproduce the interferometric observations, that is, models that satisfy simultaneously
(10)
where the minimum is taken over the entire grid of models. We then pick the models that satisfy (11)with the minimum taken over the selected subset. Finally, the best model is defined as the one with the lowest value in .
### 7.4. Modeling results
We discuss the modeling results for the four dust species that satisfy the optical extinction law.
Iron oxide. The opacities of the magnesium/iron oxides show a lack of opacity in the near-infrared and a smooth, broad band around 20 μm. The models that best reproduce the interferometric data therefore have spectra with a strong excess at mid-infrared wavelengths and a moderate near-infrared excess. The observed infrared spectrum of HR 4049 clearly does not have this shape. Magnesium/iron oxides are excluded as the dominant opacity source in the circumbinary disk.
Magnetite. None of the models in the computed grid satisfies the interferometric criterium (Eq. (10)) and reproduces both visibilities and closure phases simultaneously. Ignoring the bad fit to the interferometry, some models have spectra that match the observed infrared spectrum well. However, like the iron oxides, the magnetite opacities have structured spectra in the 10–30 μm range. This results in a clear feature at 17 μm in the model spectra, which is not seen in the observations of HR 4049 (see Fig. 7). We reject magnetite.
Metallic iron. While the interferometric observations can be reproduced relatively well, not a single one of the models in the grid with metallic iron produces an infrared spectrum that is compatible with the observed spectrum. All the model disks are optically thin at infrared wavelengths. The spectrum is therefore proportional to a gradient of blackbody curves, multiplied with the opacity. Due to the steep decline of the opacity curve of metallic iron towards long wavelengths, the infrared spectra of all metallic-iron models are skewed, with a strong shoulder at near-infrared wavelengths (1–2 μm). This is inconsistent with the observed infrared spectrum.
To reduce the strong near-IR bump and get the peak of the emission at 4–5 μm, as observed in the spectrum of HR 4049, the metallic iron has to be cooler than ~600 K. Even in model disks with the largest inner radii (30 AU), however, the iron grains are too hot (1100 K) because of the high optical-to-infrared opacity ratio of metallic iron. Expanding the grid to even larger inner disk radii would improve the spectral match, but the interferometric data do not allow for a larger angular extent of the disk on the sky. Metallic iron is removed from the shortlist of dominant opacity sources in the disk around HR 4049.
Amorphous carbon. The disk models with amorphous carbon provide significantly better fits to the infrared observations. A few dozen grid models satisfy both the interferometric criterium (Eq. (10)) and the spectral criterium (Eq. (11)). The parameters of the best model are listed in Table 5. The error bars represent the spread around the best model parameters of those grid models that satisfy the criteria.
The spectrum of the best amorphous-carbon model is plotted in Fig. 7. The match between the shape of the modeled spectrum and the observed infrared spectrum is remarkable. The fit to the interferometric data is shown in Figs. 8 to 12. The low-resolution AMBER visibilities (Fig. 8) span the H and K bands. The relative flux contribution of the spatially unresolved primary star to the total flux decreases towards longer wavelengths, from ~0.6 at the blue end of the H band to ~0.2 at the red end of the K band. We take this effect into account (see Appendix B). It leads to higher visibilities at short wavelengths.
Fig. 7Model fit to the ISO-SWS spectrum of HR 4049. The spectrum of the best amorphous-carbon model is shown (red), along with the best magnetite model (cyan) and the best fit with a single blackbody (T = 1200 K, green). Open with DEXTER
Fig. 8Low-resolution (LR-HK) squared visibilities of HR 4049 as a function of spatial frequency. Top to bottom: observed squared visibilities , model squared visibilities , and residual squared visibilities . Colors refer to the wavelength of the observation: from 1.6 μm (blue) to 2.4 μm (red). The gap visible for each observation is the band gap between the H and K bands. The H-band squared visibilities are higher than the K-band measurements because of the higher flux contribution of the unresolved primary star at short wavelengths. Open with DEXTER
Deviations between the observed and modeled visibilities are largest in the H band. The AMBER observations were obtained using the fringe tracker FINITO when the weather conditions allowed (see Sect. 2.1). Only 30% of the H-band flux of HR 4049, intrinsically an already faint AMBER target, is transmitted to the science detector. Even when the weather conditions were worse, and FINITO could not be used, the H-band flux was low. As a result, the uncertainties on the H-band correlated fluxes are large. Moreover, systematic calibration errors may occur. Decreasing quality of the fringe measurements generally leads to a loss of coherence, reducing the calibrated visibilities if the measurements of the calibrator are of better quality than those of the science target. In Fig. 8, it can be seen that the model visibilities systematically exceed the observations, which may point to this effect. It is also possible that the flux ratio of the star and disk deviates from the model in the H band. However, this flux ratio is constrained by the Kurucz stellar atmosphere model, fit to the optical photometry, and the ISO-SWS infrared spectrum, and fixed in the radiative transfer modeling (see Appendix B). This approach is self-consistent, and comparison of the data sets at different wavelengths and with different instruments, which is necessary for our investigation, remains possible.
Fig. 9Medium-resolution (MR-2.1 and MR-2.3) squared visibilities of HR 4049. Colors refer to different baselines: respectively blue, red, and green for the first, second and third baseline of observations (k) to (n) in the order listed in Table 1. Top to bottom in each panel: observed , model V, and residuals . Open with DEXTER
Fig. 10Low-resolution (LR-HK) closure phase measurements of HR 4049. Each panel refers to a baseline triangle. The letter in the top corner refers to the corresponding entry in Table 1. Measurements are indicated by black dots with error bars; the red line represents the model. Open with DEXTER
Fig. 11Medium-resolution (MR-2.1 and MR-2.3) closure phase measurements of HR 4049. Symbols are similar to those in Fig. 10. Open with DEXTER
Fig. 12MIDI relative visibilities V29m/V15m. Black dots are the data; the red line is the model. Open with DEXTER
Because of the large uncertainties of the H-band visibilities, the interferometric model is mostly constrained by the low- and medium-resolution K-band measurements. The latter are reproduced well: the two local minima seen in the low-resolution K-band visibilities (at spatial frequencies around 60 and 150 cycles/arcsec; Fig. 8) and the relative shape of the medium-resolution visibilities (Fig. 9).
The orientation of the disk on the sky is mostly constrained by the LR-HK closure phase series (c) to (g) (see Table 1). These observations were obtained consecutively on a single baseline triangle. Due to the Earth’s rotation, the baseline lengths and orientations on the sky change during the night. The model reproduces nicely the observed trend of the closure phases with time (Fig. 10). Also the medium-resolution closure phases are matched by the model (Fig. 11). The MIDI relative visibilities, shown in Fig. 12, are reproduced perfectly.
The model disk density and temperature structure are shown in Fig. 13. Model images at 2.2 μm and 10 μm are displayed in Fig. 14. Note that the disk is moderately optically thick at optical wavelengths but optically thin at infrared wavelengths, in contrast to the very optically thick wall model of Dominik et al. (2003).
Fig. 13Density and temperature structure of the best model. R is the radial distance to the primary, z the vertical height above the disk midplane. The color scale and black contours indicate the local temperature of the amorphous carbon in Kelvin. White contours indicate the local density with respect to the maximal density at R = Rin and z = 0. The dotted line is the line of sight towards the primary. Open with DEXTER
### 7.5. The distance to HR 4049 revisited
We may be able to differentiate between the two possible distances to HR 4049 found in Sect. 6. Our best models have a binary stellar mass of 1.1 ± 0.1 M and 2.8 ± 0.3 M for a distance of 640 and 1050 pc, respectively. By means of the mass function of the primary, derived from optical spectroscopy (0.158 ± 0.004 M, Bakker et al. 1998), and the now known inclination of the system, the binary mass can be converted to the masses of the individual stars. For a distance of 1050 pc, the primary and secondary mass are 1.6 ± 0.2 M and 1.1 ± 0.1 M, respectively. Such a primary mass is excessively high for a white dwarf, which makes a distance of 1050 pc unlikely. At a distance of 640 pc, the primary and secondary have a lower mass of 0.4 ± 0.1 M and 0.7 ± 0.1 M, respectively. This primary mass is within the expected range for a post-AGB star. We conclude that the most likely distance to HR 4049 is 640 pc.
With an effective temperature of 7500 ± 200 K and an angular diameter of 0.45 ± 0.03 mas at a distance of 640 ± 190 pc, the primary has a radius of 31 ± 9 R and a luminosity of 2800 ± 1700 L for a stellar mass of 0.4 ± 0.1 M. This is close to what is expected from Paczyński’s core mass-luminosity relation: a luminosity of 2800 L corresponds to a stellar mass of ~0.55 M (Paczyński 1970a,b). The inferred surface gravity log g is 1.1 ± 0.3 dex, consistent with the spectroscopic value of 1.0 ± 0.5 dex.
At a distance of 1050 ± 320 pc, the primary’s radius and luminosity would be 50 ± 15 R and 8000 ± 4000 L, for an (unlikely) mass of 1.6 ± 0.2 M. Also in this case, log g = 1.2 ± 0.3 dex is consistent with the spectroscopic value, but, again according to the mass-luminosity relation, the luminosity corresponds to that of a post-AGB star that is only half as massive.
Table 5
Parameters of the best model.
## 8. Conclusions
### 8.1. Discerning metallic iron and amorphous carbon
With our case study of HR 4049, we have shown that the combination of infrared spectroscopy and interferometry is a powerful tool for discriminating between dust species with featureless opacities. While the spectrum is related to the temperature structure of the circumstellar dust, the high-angular-resolution data constrain the physical location of the material. Dust species that are not in thermal contact have different temperatures at the same physical location from the illuminating source because of their different absorption/emission properties.
In general, by measuring the temperature of the dust and its location, one can constrain the type of dust under consideration. This is specifically true for small metallic iron and amorphous carbon grains. Both species are expected to be abundant in different astrophysical environments, e.g., AGB winds and circumstellar disks, but their identification based on the infrared spectrum alone is impossible. Fortunately, the opacity of metallic iron decreases more quickly towards longer wavelengths than that of amorphous carbon (Fig. 6). This makes metallic iron grains much hotter than amorphous carbon grains under the same optical irradiation. Spatially resolved observations lift the ambiguity. The combination of spectroscopy and interferometry is therefore a very promising tool for identifying these dust species in a wide range of astrophysical environments.
### 8.2. A consistent image of HR 4049
The system HR 4049 consists of a binary located at a distance of 640 pc, surrounded by a circumbinary dust- and gas-rich disk. It contains an evolved, 0.4 ± 0.1 M, 7500 ± 200 K star, and an undetected 0.7 ± 0.1 M secondary. Under the assumption that the latter is on the main sequence, this mass corresponds to that of a K-type star.
Fig. 14Best-model image at 2.2 and 10 μm. North is up, east is left. At a distance of 640 pc, 1 mas corresponds to 0.64 AU. The dashed line in the right panel indicates the photocenter location of the PAH 11.3 μm emission region relative to the disk center, projected on the N − S axis (xns). The photocenter position in the E − W direction is not constrained (see Sect. 8.2.2). Open with DEXTER
#### 8.2.1. The circumbinary disk
The binary is surrounded by a circumbinary disk, rich in gas and dust. Our model indicates that small amorphous carbon grains are the dominant source of opacity. The total dust mass in these grains required to reproduce the near- to mid-infrared observations is only 10% of a Moon mass.
The radial extent of the disk seen in the near- and mid-infrared is limited to a few tens of AU. The disk is optically thick to the stellar radiation in radial direction, but almost optically thin at infrared wavelengths. The ratio of the total infrared excess luminosity and the stellar luminosity of the best model is 25%, lower than the observed 33% (Dominik et al. 2003). The difference between the thermal emission of the model and the photometric observations occurs at wavelengths beyond the mid-infrared, where our model fails (as explained in Sect. 7.1). This discrepancy at long wavelengths can be phenomenologically solved by including large (>several μm) and cold dust grains either in the midplane of the disk or at larger distances from the star. Inclusion of a dust component of this kind results in additional emission at long wavelengths, while the appearance of the disk at optical and mid-infrared wavelengths remains similar.
The spectral energy distribution of HR 4049 is shown in Fig. 5. While our model provides a satisfying fit at short wavelengths, it underestimates the flux beyond 20 μm. A fit with a 200 K blackbody representing the cold dust component in the disk provides an ad hoc solution to this problem. We scaled the blackbody so that the SCUBA 850 μm flux is matched. The radiating surface of the blackbody is 740 mas2 (i.e., 30% of the midplane surface of our model projected on the sky). We note that a single-temperature blackbody fit (1200 K) does not fully grasp the shape of the spectral energy distribution either (Fig. 5).
The optical spectrum of HR 4049 shows the [O i] 6300 Å emission line. The position and width of the line profile do not change with orbital period, which made Bakker et al. (1996) conclude that the emission region is located in the circumbinary disk. This is not uncommon for early-type stars surrounded by a disk; also pre-main-sequence stars display disk [O i] emission (Acke et al. 2005). The broadening of the line is due to the Keplerian velocity of the line formation region in orbit around the star/binary. With our value for the binary stellar mass of HR 4049 we derive a Keplerian velocity at the inner radius of the circumbinary disk of vin = 9 ± 1 km s-1, in perfect agreement with the feature’s full width at half maximum of 20 km s-1 (Bakker et al. 1996). Hinkle et al. (2007) have determined the widths of the infrared CO lines to be in the range of 16–18 km s-1. Adopting our model parameters, this broadening is consistent with a disk origin of the CO emission as well7.
#### 8.2.2. PAH outflow
The far side of the circumbinary disk is oriented towards PA = 130°. The VISIR spectroscopy indicates that the photocenter of the PAH emission, projected onto a N − S axis, is located south of the photocenter of the disk emission. These observations are consistent with a bipolar outflow, perpendicular to the disk midplane, along the rotation axis of the disk. The receding lobe is oriented towards PA = 310°. Compensating for the PAH-to-total flux ratio (fpah = Fpah/Ftotal) and taking into account the orientation of the disk (PA), one can compute the photocenter displacement of the PAH emission region on the sky x from the photocenter displacement measured in the N − S direction by VISIR xns using (12)The photocenter of the PAH 11.3 μm emission region on the sky is located 40 ± 10 mas (26 AU at 640 pc) from the disk center, comparable to the extent of the disk at these wavelengths (Fig. 14). This again shows that the emission region is much larger than the circumbinary disk and is most likely a bipolar outflow.
#### 8.2.3. Diamonds
HR 4049 is one of the very few astronomical sources that displays the near-infrared emission bands of hydrogenated diamonds (Geballe et al. 1989; Guillois et al. 1999). The pre-main-sequence star HD 97048 is also surrounded by a disk containing diamonds (Acke & van den Ancker 2006). The infrared spectrum of HD 97048 shows strong PAH emission emanating from the disk and no sign of silicate emission. The geometry of the disk is remarkable as well: mid-infrared imaging has shown that it is an extremely flared, i.e., bowl-shaped, disk (Lagage et al. 2006). Carbonaceous grains provide a straightforward explanation for the featureless continuum, while the large disk opening angle may reflect strong heating via hydrocarbon molecules and very small grains. Here, we report that also the circumbinary disk around HR 4049 is rich carbonaceous dust.
Acke & van den Ancker (2006) searched for observational characteristics that set apart diamond sources from others, but found none. Here, we suggest that a carbon-dominated dust chemistry is a necessary condition to form the diamonds and/or make their features appear in the infrared spectrum.
## 9. Discussion
HR 4049 belongs to a fairly large group of evolved binary stars surrounded by a circumbinary disk (Van Winckel 2003). The orbital parameters are such that the evolved objects must have been subject to severe binary interaction processes when at giant dimensions. The systems managed to avoid the strong spiral-in and reveal themselves as long-period (>100 days), mainly eccentric binaries, often still surrounded by a stable dusty disk (e.g., Van Winckel et al. 2009). A recent study of optically bright objects in the Large Magellanic Cloud has shown that disk sources are also rather common there among the post-AGB population. Because of the known distance to the LMC, their location in the Hertzsprung-Russell diagram is better constrained. The primary stars in these systems display a wide range in luminosities and hence in initial mass (van Aarle et al. 2011). This indicates that disk formation does not depend vitally on the primary’s initial mass, but rather on the dimensions of the binary system and of the primary during the thermally pulsing AGB phase.
Investigation of the infrared spectra of circumbinary disks around evolved binaries has indicated an oxygen-rich dust mineralogy in most systems. Amorphous and crystalline silicate features are dominant (Gielen et al. 2008, 2011a). The evolutionary scenario (Waters et al. 1998; Molster et al. 1999; Van Winckel 2003) assumes that the circumbinary disk is a relic of the strong binary interaction process and hence contains the chemical footprint of the former giant envelope out of which it was formed. The dominant occurance of purely oxygen-rich material shows that the interaction processes occured prior to the evolutionary phase when enough thermal pulses with dredge-up would have made the star carbon-rich. Only a few objects display PAH emission features, and some even fullerene emission features, on top of the dust spectra which are dominated by (crystalline) silicate features (Gielen et al. 2011a,b).
In this context, HR 4049 is an exception to the rule. The emission bands in the infrared spectrum are all attributed to carbonaceous species and we have shown in this paper that the continuum emission is also produced by carbon grains. There is no sign of silicates. We stress, however, that large (≫10 μm) silicate grains may be present in the disk. These grains have a smooth spectral signature, that would be veiled by the spectrum of the small carbon grain component. The presence of large grains may be suggested by the strong far-infrared excess, not reproduced by our model. The particular nature of HR 4049 is highlighted by the contrasting oxygen-rich chemistry of the circumbinary gas.
The mass of the secondary star in HR 4049 does not exclude it from being a compact object, which may have been a source of circumbinary material as well. If indeed the current companion is a white dwarf, it does not show symbiotic activity and it should be cool and hence old (Jorissen et al. 1998). It is therefore unlikely that circumstellar matter from the now cool white dwarf would still be present in a dust and gas-rich environment. The disk would then have survived the vast energy releases and dimensional increases of the current primary during its thermal pulses. Moreover, old mass loss from a carbon star cannot explain the oxygen-rich chemistry of the circumbinary gas. We conclude that the current circumstellar matter most likely comes from the current, luminous primary.
We describe our interpretation of the observed dust and gas chemistry in the circumbinary disk. The primary is losing mass, as evidenced by the P-Cygni profile of the Hα line (Bakker et al. 1998). This mass loss bears the chemical signature of the photospheric abundance pattern. The primary photosphere has a C/O ratio below or close to unity (Lambert et al. 1988) and is strongly depleted in refractory elements such as iron, but also silicon. Because of this depletion, silicates cannot form in the current outflow of HR 4049. The outflowing material is still oxygen-rich, but the oxygen atoms cannot form dust because of the absence of refractory elements. The oxygen therefore only forms molecules with the abundantly available hydrogen and carbon: OH, H2O, CO, and CO2. The carbon atoms, on the other hand, are able to form large molecules (PAHs, fullerenes) and very small dust grains (diamonds and amorphous carbon grains). In other words, because of the lack of refractory elements in the current mass loss of the primary, only carbonaceous dust can be formed, despite the intrinsically oxygen-rich chemistry.
The carbonaceous dust is confined to the circumbinary disk, while the outflow contains carbon-rich molecules. This is consistent with our hypothesis: the spherical outflow of the primary is probably too tenuous to form dust grains and so only (large) molecules are formed. However, the gas-rich disk intercepts and slows down the wind in the binary plane. There, the densities become large enough for dust to condense. The amorphous carbon grains form a veil over the pre-existing disk.
The question remains why only HR 4049 displays this particular circumstellar chemistry among the evolved binaries with disks. The answer is probably linked to the extreme depletion pattern of the primary photosphere. The re-accretion of metal-poor gas in the previous evolutionary phases apparently was so efficient, that subsequent mass loss from this photosphere became completely depleted of refractory elements. If this hypothesis holds, the disk around HR 4049 must contain silicates and iron-bearing dust, but their spectral signature is overwhelmed by that of the amorphous carbon. In this context, HD 52961 is an interesting target for a similar study to the one presented here. The primary in this evolved binary also displays an extreme depletion pattern and the infrared spectrum indicates the presence of PAH molecules, fullerenes, and CO2 (Gielen et al. 2011b). However, silicate emission is also detected. The current outflow in HD 52961 is similar in composition to the one in HR 4049. We therefore expect that carbonaceous grains are currently forming in this circumbinary disk as well.
6
In the literature, the disk position angle commonly refers to the angle of the major axis on the sky. This angle is ±90° offset with our disk PA. Nonetheless, we use our PAdefinition because it does not suffer from a 180° degeneracy.
7
Hinkle et al. (2007) assumed an inner dust-disk radius of 10 AU and mention that the CO gas is located at the inner radius if the total binary mass is 0.9 M. Our models constrain both parameters, and place the disk at a slighly larger distance from the binary, but also indicate a slightly higher binary mass.
9
This is because visibility measurements probe structures of the size of the inverse of the spatial frequency, while closure phases can be measured with a precision of only a few degrees, and thus are sensitive to deviations from point symmetry on an angular scale two orders of magnitude smaller.
## Acknowledgments
This research has made use of the AMBER data reduction package of the Jean-Marie Mariotti Center8. The authors thank D. Pourbaix for his much appreciated help with the Hipparcos data and the anonymous referee for helpful comments.
## Online material
### Appendix A: From images to complex visibilities
The radiative-transfer code MCMax produces images on a predefined grid of pixels on the sky. We chose a 256 × 256 grid covering a field-of-view of 100 mas × 100 mas. This results in an angular resolution of 0.39 mas per pixel.
The model image produced by MCMax for a given set of parameters (M , Rin, Rout, Mdust, p, i) has a default disk orientation angle on the sky of 0° E of N. That is, the far side of the inclined disk is oriented towards the north. This image is rotated according to the grid disk PA under consideration to yield the model image corresponding to (M , Rin, Rout, Mdust, p, i, PA).
For a specific observational setting with baseline length b, baseline orientation angle θ, and at wavelength λ, the van Cittert-Zernicke theorem gives the complex normalized visibility (A.1)where (u = bsinθ/λ,v = bcosθ/λ) are the spatial frequencies, (α,β) the angular coordinates, and B(α, β) the brightness distribution (i.e., the image) of the source on the sky, normalized to a total intensity of unity.
To compute , the image is rotated through the angle θ. This is equivalent to a coordinate transform such that (u′,v′) = (0,b/λ) and (α′,β′) = (αcosθ − βsinθ,αsinθ + βcosθ). Equation (A.1) becomes Numerically, the integration over α′ reduces to a sum over the first dimension of the rotated image B(α′,β′). The second integration is a one-dimensional Fourier transform and can be done quickly with the fast Fourier transform (FFT) algorithm. However, FFT converts the 256-array with a pixel step of 0.39 mas into a 256-array with a spatial-frequency step of 10 cycles/arcsec. Since the observations are obtained at spatial frequencies in the range 25−370 cycles/arcsec, the default FFT resolution is too coarse for direct comparison. To increase the resolution in spatial frequency, the 256-array (i.e., dαB(α′,β′)) is placed in a 1024-array, which is zero outside the image. The FFT of the latter array yields a spatial-frequency step of 2.5 cycles/arcsec. This higher resolution makes the FFT result smooth enough to allow interpolation at the exact spatial frequencies of the observations.
The method was tested on images of simple geometries (point source, binary with unresolved components, uniform disk, uniform ellipse), for which analytic formulae of the complex visibility exist. Good agreement was found. For a uniform disk with a diameter of 10 mas, the absolute difference between the analytic and image-based squared visibilities is 0.002 on average, and always below 0.01. The absolute difference between the analytic closure phase (i.e., 0° or 180° for a uniform disk) and the image closure phase is 1° on average, but can increase to 10° at the longest baselines. At these high spatial frequencies, pixelation effects start to play a role for the closure phases, while they do not affect the visibilities to a measurable level9.
The obtained accuracy of the model is sufficient for the goals of this paper. An increase of the spatial resolution of the model image is possible, but would lead to an increase of the grid computation time from days to weeks.
### Appendix B: Stellar contribution in the near-infrared
In the near-IR, the flux contribution of the central star to the total flux can be large. The stellar flux contribution of the primary of HR 4049 drops from ~0.6 at 1.6 μm to ~0.2 at 2.5 μm. The intensity-normalized image of the disk, on the other hand, is similar in the H and K band. We therefore took the following approach to compute squared visibilities and closure phases in the near-IR:
• 1.
From the radiative-transfer model, we computed a2.2 μm image. The central2 × 2 pixels in this image contain the primary star. We removed the star from the image by replacing these central pixel values by interpolated values. Hence, we created a star-less image, which provides a representative disk image at all wavelengths between 1.6 and 2.5 μm.
• 2.
We computed the disk complex visibilities from the star-less image as described in Appendix A.
• 3.
From the model infrared spectrum and the input Kurucz model for the primary star, the stellar-to-total flux contribution f was estimated at all AMBER wavelengths.
• 4.
The final model visibilities were computed from the disk visibilities and the flux ratio f, according to (B.1)From this complex quantity, squared visibilities (per baseline and wavelength) and closure phases (per baseline triangle and wavelength) were computed. Given its angular diameter (0.45 ± 0.03 mas, determined from the Kurucz model fit to the optical photometry), the primary star is unresolved at the spatial resolution of the observations. Moreover, we assumed the primary star is at the disk’s center and hence . Note that we neglected the possible offset of the primary star with respect to the disk center due to binary motion. However, given the dimensions of the disk (~15 mas) and of the binary (~1 mas), the effect of such an offset on visibilities and closure phases is expected to be small. Moreover, the interferometric observations were taken close to minimal brightness, when the primary star was close to the observer. The primary was therefore close to projected minor axis of the disk and close to the disk center on the sky.
In the mid-IR, the relative flux contribution of the primary star to the total flux is less than a few percent. Moreover, it is constant over the N band because of the near-blackbody shape of both the stellar flux and the excess. The intensity-normalized model image of HR 4049 at 8 μm is therefore the same as at 13 μm. The variations in (relative) visibility over the N band are exclusively due to a change in spatial frequency and not due to a change in disk geometry or stellar flux contribution with wavelength.
## All Tables
Table 1
Log of the AMBER and MIDI interferometric observations.
Table 2
Tested dust species, sizes, and shapes.
Table 3
Dust species with extinction curves consistent with the Geneva color–magnitude diagrams (X2 < 3, see Eq. (4)).
Table 4
Grid parameters of the radiative-transfer models.
Table 5
Parameters of the best model.
## All Figures
Fig. 1Infrared spectrum of HR 4049 (black: ISO-SWS, blue: Spitzer-IRS). The prominent features between 6 and 13 μm are caused by PAHs. The band between 4 and 5.3 μm is the result of a forest of CO, OH, and H2O molecular emission lines (Hinkle et al. 2007). Emission lines of CO2 are visible longward of 13 μm (Cami & Yamamura 2001). Open with DEXTER In the text
Fig. 2Spatial-frequency coverage of the interferometric measurements. Black dots refer to AMBER data, red dots to MIDI data. Open with DEXTER In the text
Fig. 3Six independent Geneva color–magnitude diagrams of HR 4049. The linear-regression fit to the data is shown in black. The other curves show the color/magnitudes of the Kurucz model, reddened with the interstellar extinction law of Cardelli et al. (1989, foreground extinction) and with different dust species with a grain size of 0.01 μm and an appropriate range of column densities (variable circumstellar extinction). The grain shape distribution is DHS with fmax = 0.8, except for amorphous carbon (Mie, i.e., DHS with fmax = 0). Top left panel: the discrepancy between the observed and the modeled U − B color may be due to a UV-excess in the binary system. Open with DEXTER In the text
Fig. 4a) ISO-SWS spectrum in the N-band range. The PAH features at 8.6, 11.3, 12.0, and 12.7 μm are indicated, the dashed line represents the continuum. b) Spatial extent along the slit north-south direction of VISIR. The dashed line indicates the width of the spatially unresolved continuum, which increases with wavelength. c) Relative spatial position with respect to the continuum along the slit direction of VISIR. The PAH emission region is extended on a scale of several 100 s of AU and its photocenter is located towards the south of the continuum emission region. Open with DEXTER In the text
Fig. 5Spectral energy distribution of HR 4049. The ISO-SWS spectrum (grey line), and IRAS 25, 60, and 100 μm, and SCUBA 850 μm photometry (grey boxes). The green line is the fit with a single blackbody (1200 K, in accordance with Dominik et al. 2003). The spectral energy distribution of our model (blue) underestimates the flux at λ > 20 μm. The red line shows our model plus a 200 K blackbody, scaled to the SCUBA 850 μm flux. See Sect. 7 for details. Open with DEXTER In the text
Fig. 6Opacity curves of the four dust species that satisfy the optical extinction law towards HR 4049, normalized by κV (at 0.55 μm). The grain size is 0.01 μm, the grain shape distribution is either DHS with fmax = 0.8, or Mie (fmax = 0). Open with DEXTER In the text
Fig. 7Model fit to the ISO-SWS spectrum of HR 4049. The spectrum of the best amorphous-carbon model is shown (red), along with the best magnetite model (cyan) and the best fit with a single blackbody (T = 1200 K, green). Open with DEXTER In the text
Fig. 8Low-resolution (LR-HK) squared visibilities of HR 4049 as a function of spatial frequency. Top to bottom: observed squared visibilities , model squared visibilities , and residual squared visibilities . Colors refer to the wavelength of the observation: from 1.6 μm (blue) to 2.4 μm (red). The gap visible for each observation is the band gap between the H and K bands. The H-band squared visibilities are higher than the K-band measurements because of the higher flux contribution of the unresolved primary star at short wavelengths. Open with DEXTER In the text
Fig. 9Medium-resolution (MR-2.1 and MR-2.3) squared visibilities of HR 4049. Colors refer to different baselines: respectively blue, red, and green for the first, second and third baseline of observations (k) to (n) in the order listed in Table 1. Top to bottom in each panel: observed , model V, and residuals . Open with DEXTER In the text
Fig. 10Low-resolution (LR-HK) closure phase measurements of HR 4049. Each panel refers to a baseline triangle. The letter in the top corner refers to the corresponding entry in Table 1. Measurements are indicated by black dots with error bars; the red line represents the model. Open with DEXTER In the text
Fig. 11Medium-resolution (MR-2.1 and MR-2.3) closure phase measurements of HR 4049. Symbols are similar to those in Fig. 10. Open with DEXTER In the text
Fig. 12MIDI relative visibilities V29m/V15m. Black dots are the data; the red line is the model. Open with DEXTER In the text
Fig. 13Density and temperature structure of the best model. R is the radial distance to the primary, z the vertical height above the disk midplane. The color scale and black contours indicate the local temperature of the amorphous carbon in Kelvin. White contours indicate the local density with respect to the maximal density at R = Rin and z = 0. The dotted line is the line of sight towards the primary. Open with DEXTER In the text
Fig. 14Best-model image at 2.2 and 10 μm. North is up, east is left. At a distance of 640 pc, 1 mas corresponds to 0.64 AU. The dashed line in the right panel indicates the photocenter location of the PAH 11.3 μm emission region relative to the disk center, projected on the N − S axis (xns). The photocenter position in the E − W direction is not constrained (see Sect. 8.2.2). Open with DEXTER In the text
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https://www.bradford-delong.com/2019/01/a-framework-for-economic-analysis-of-tax-regulations.html
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This is the word on how the government ought to analyze proposed tax regulations: Greg Leiserson and Adam Looney: A Framework for Economic Analysis of Tax Regulations: "Treasury and the IRS should conduct a formal economic analysis of regulations in two cases. First, for regulations that implement recent tax legislation, the agencies should conduct an analysis if they have substantial discretion in designing the regulation and if different ways of doing so would vary substantially in their economic effects. Second, for regulations unrelated to recent legislation, the agencies should conduct an analysis if the regulation would have large economic effects relative to current practice...
...The economic analysis conducted in these cases should focus on the revenues raised and the economic burden imposed on the public as a result of the agencies’ exercise of discretion or the new application of existing authority. The revenues raised and the burden imposed reflect the fundamental tradeoff in taxation, and thus determine a regulation’s costs and benefits. However, the analysis should not attempt to quantify the net benefit or net cost of a regulation as doing so would require the agencies to make controversial assumptions about the social value of revenues and the appropriate distribution of the tax burden. Treasury’s Office of Tax Analysis is well-equipped to provide estimates of revenues and burden as they can be built from analyses the Office already produces: revenue estimates, distributional analyses, and compliance cost estimates...
#shouldread #fiscalpolicy
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https://www.physicsforums.com/threads/phase-shift-issue-in-dominant-pole-compensation-strategy.857590/
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# Phase shift issue in Dominant Pole Compensation strategy....
1. Feb 16, 2016
### brainbaby
The next hurdle in my understanding of frequency compensation comes as following…
As the text says…
My problem is that as we move from point 1 to 2, the frequency increases so the phase shift should also increase..(as phase shift depends on frequency)… but the text however says that the phase shift will be constant at 90 deg with a 6db roll off..so what is this paradox..??
Either the text should say that "open loop gain falls at 6db/ octave with a varying phases shift of 90 deg..”
Isn't...!!
2. Feb 16, 2016
### LvW
No - why do you think that the phase shift is ALWAYS increasing with frequency?
Two examples:
* For poore resistive circuits the phase hift is always zero
* For an ideal integrator (or a RC network for very large frequencies) the phase shift is constant at -90deg.
Example second order:
H(s)=A/(1+as +bs²)
For very high frequencies we have H(s)=A/s²= - A/w² .
And the "-" sign is identical to a constant phase shift of -180deg.
(This is what the text says).
However, the text is somewhat simplifying. The term "constant" refers to the asymptotic lines of the real curve phase=f(frequency). As the above function H(s) shows: The phase assumes 180 deg for infinite frequencies only.
3. Feb 16, 2016
### brainbaby
Due to increasing frequency the stray capacitance both inside and outside the amplifier comes in action hence cause the phase shift or phase delay to occur....by why it increases..I certainly don't have any idea of it..
4. Feb 16, 2016
### LvW
OK - correct. Parasitic effects are always existent and - as a result - there will be always a negative phase shift for rising frequencies, even for an ohmic voltage divider.
I did not know that you were speaking about such effects.
And, of course, the text as cited by you did not take into account such effects.
So - what is your problem?
As a - more or less - phliosophical aspect: In electronics there is NO formula or rule that is correct by 100% (and this is true even for the "resistive" voltage divider).
Everything contains some simplifications and neglects unwanted effects which - hopefully -become effective for frequencies only which are beyond the working range.
5. Feb 16, 2016
### brainbaby
Oh I am really sorry..I forgot to attach an image...which will present my point of query..
What I mean to say is that if we move from point 1. to point 2. frequency is increasing...correct..so the phase shift should also become more prominent..
But in the text it is written that or means that for a 6 db roll off the phase shift would be a constant 90 degree....(as we progress down the slope the frequency on the horizontal axis increases)
So why they said that the phase shift would be constant...either they should say "open loop gain falls at 6db/ octave with a varying phases shift of 90 deg..”
6. Feb 16, 2016
### Jony130
In short. The dominant pole capacitor (single capacitor) can provide only 90 deg phase shift max.
And we select dominant pole capacitor in such a way that the loop gain drops to 1 with slope 6dB per octave at a frequency where the poles of uncompensated amp contributes very small to the total phase shift. This ensures that the phase shift is greater than -180 deg and we have a stable amplifier.
See the plot (single pole)
And notice that for F > 10*Fc phase shift is constant and equal to -90 deg.
Where Fc is a cutoff/corner frequency Fc = 1/(2 * pi * R*C).
Also do you know why roll-off is equal to 6dB per octave (20dB per decade) ? If not you should really back to basics.
And here you have a example of a second order (two poles) frequency response
Last edited: Feb 16, 2016
7. Feb 16, 2016
### jim hardy
@brainbaby
Remember asymptotes ?
Here's where technicians get an advantage
my high school teacher had us boys calculate, tabulate and plot, calculating by slide rule , on log paper
Vout/Vin for this simple circuit
from a couple decades below to a couple decades above break frequency
Vout/Vin = JXc/(R+jXc)
now - when you struggle through that exercise with all its slide rule polar to rectangular conversions
you'll see the pattern emerging
At low frequency Xc >> R so that fraction's denominator is very nearly jXc
and fraction jXc/(nearly jXc) is nearly 1, with almost no phase shift because the j's almost cancel (pardon my math liberty?)
At high frequency Xc is becoming vanishingly small
numerator is that small number multiplied by j
denominator is R plus the comparatively small numerator
so the fraction becomes j X (a vanishingly small numerator)/(an almost constant denominator)
jXc/(R+j(almost_nothing)) is very nearly: jXc/R ,
only one operator j is left for all practical purposes.
while you can't by math get rid of the j in denominator you can (by observation of the calculated numbers in your exercise) see that it becomes insignificant ,
for all practical purposes it vanishes
so phase shift is asymptotic to 90 degrees not equal , but slide rule accuracy is accepted as 3 figures.
Then it's intuitive that a single pole gives 90 degrees
and another pole would give 90 more
Once you believe that it gives you confidence in the math that edit Jony is Jony and Lvw are presenting so well
But i wouldn't have ever learnt it without that high school technician's exercise.
Maybe you should try it - do about twenty frequencies so it sinks in.
Plodders like me need to be taught in sequence What→How→Why , not Why→What→(How left to you to figure out)...
sophiecentaur always says "Work the maths!" . This is a case where doing it with real numbers will be more instructive than alphabet juggling.
Once it's soaked in you can make an elegant derivation, I expect that would feel great.
hope it helps
old jim
Last edited: Feb 17, 2016
8. Feb 17, 2016
### brainbaby
Oh It seems I get it......
Actually the phase shift depends directly upon the occurrence of poles and indirectly on increase in frequency …because if a pole occurs that means another capacitor comes into action …however the role of frequency in causing phase shift depends on the time when that frequency creates a pole…..
so rather we should say that
by increasing the frequency the number of poles increases, and if pole increases then only then phase shift increases…
so its the frequency which initiates a capacitor to cause the phase shift..
So now my inference seems to agree with what LvW stated in post 2 first lines....
Hence the word "constant" in the text is right...
Isn't..??
9. Feb 17, 2016
### LvW
...indirectly? What does that mean?
In frequency-dependent circuits, the phase shift between input and output directly depends on frequency (is a function of frequency).
However, how this function looks like (first order, second order, poles only or poles and zeros) depends on the circuit and its transfer function - expressed using the pole and zero location. OK?
..on the time?
No - the number of poles is a property of the circuit (a property of the transfer function) and has nothing to do with the applied frequency.
Again: The function of phase shift vs. frequency depends on the circuit and its frequency-dependence only.
For finding the approximate form of the phase function (in form of asymptotic lines) we are using the pole and zero location because we know what happens at these specific frequencies: At a pole (zero) the slope becomes more negativ (positive) by 20dB/dec.
10. Feb 17, 2016
### brainbaby
As we all know that a capacitor introduces a 90 deg phase shift...right..yes ....I agree that phase shift depends upon frequency...
Being indirectly I mean that... see the figure in post 5..here for uncompensated curve at point 2 ..a 90 deg phase shift is introduced...and in between point 2 and point 3 the frequency is increasing but the phase shift is same i.e 90 deg...,now at point 3 again another phase shift of 90 deg is introduced...and the accumulated total phase shift is 180 deg..but again in between point 3 and point 4 frequency is increasing but phase shift is yet the same 90 deg....
So this behaviour felt to me like that the points (2,3,4) where there is a roll off(pole) the phase shift depends on the frequency and for the rest intermediate positions frequency is independent of phase shift...
However by saying that frequency is independent of phase shift I never meant that it does not depends on phase shift....yes it depends ..but it was just a way of me inferring the situation....as simple as that....
Last edited: Feb 17, 2016
11. Feb 17, 2016
### LvW
To be exact: A capacitor introduces a 90 deg phase shift between voltage and current!
For an RC element we have a frequenc-dependent shift which reaches 90 deg for infinite frequencies only!
No - the phase cannot abruptly change its value (...a 90 deg phase shift is introduced).
Study the phase response in Fig. 6 - it tells you everything you need to understand what happens.
Such "phase jumps" are only introduced in the drawing for the asymptotic lines as a help for constructing the real and smooth phase function.
Frequency is always independent on phase shift. I suppose you mean the inverse: Phase shift independent on frequency.
But this is NEVER the case. Phase shift ALWAYS depends on frequency.
Don`t mix the real phase response with asymptotic lines which serve only one single purpose: A help for roughly constructing the real curve. See the phase diagram in Fig. 6 and realize that the final value at -90 deg is reached for infinite frequencies only.
12. Feb 17, 2016
### brainbaby
My inference from figure 6....
1. Phase shift non linear function of frequency..
2. Phase shift is independent of poles because it started changing from point x before the first pole have occurred.
3. Between point 1 and 2 the phase shift is 90 deg which is said in the text to be constant because they are talking in terms of accumulated phase shift which is 90 deg..(135-45=90) < as phase cannot arbitrarily change its value>..but with each change in frequency the value of phase shift is different as seen from the curve (for f2 and f3 phase shift is p1 and p2)..…which further signifies that phase shift totally depends on frequency…however that dependence is non linear..
Am I right ?
13. Feb 18, 2016
### LvW
1.) The term "constant" in the text (your post#1) is not correct. We have a constant phase shift of 90 deg for an IDEAL integrator only (pole at the origin). However, such a circuit does not exist.
2.) Your point (2) is false. It is the pole which causes the phase to deviate from its starting value (0 deg) already for very low frequencies.
3.) For my opinion, the diagram shows everything you should know to understand what happens. If there would be no second pole, the red curve (phase) would approach the -90 deg line (which acts as an asymptotic line in this case).
14. Feb 19, 2016
### brainbaby
After rigorous analysis I came to the following conclusion...
Phase shift depends on the circuit and frequency. Phase shift shows dependence on poles which is a circuit parameter from the fact that the phase shift begins to change one decade before the pole and stops changing one decade after the pole and ends at 90 degree and this happens prior and after to each pole.
The phase shift at the pole frequency is -45 degrees or
A single filter pole adds a maximum of 90 degree phase shift for the frequencies far away from its turnover frequency(3db frequency), but the shift is only 45 degrees at the pole (-3db point).
This behaviour can be further illustrated and explained as.....
But Why does this happens...??
how phase shift knows well in advance that pole is about to come.......and its time to change....and after the zig zag happens its time to be parallel to the asymptote ...and change if another pole comes otherwise show indifference.....??...
15. Feb 19, 2016
### jim hardy
Bravo !
let's take a plausible example
R = 1000 ohms
time constant = 1 millisecond
pole then is at 1000 radians per sec = 159.15 hz
and Xc at 1000 radians/sec is 1000 ohms
a decade away, at 15.915 hz what is transfer function's magnitude and phase ?
Vout/Vin = JXc/(R+jXc)
Xc = 1/(2pifC) = 1/(2 ⋅ π ⋅ 15.915 ⋅ 1X10-6) = ⋅1.0X104
jXc/(R+jXc) = j104/(103+j104)
which = 104∠-90°/1.005X104∠-84.3° = 0.995∠-5.7°
Phase shift doesn't know anything in advance. Mother nature just built math that way.
Circuit guys struggling to do above math with slide rules figured it out and observed it's always 5.7 degrees a decade out
so they devised those predictive rules for drawing a frequency & phase plot. No magic, it's just a graphical approach that saves wear and tear on slide rules.
One Mr Hendrik Bode made the approach popular in 1930's. I don/t know if he was the absolute first to think of it but he sure advanced the field of control systems
and that's why it's called a Bode Plot.
https://en.wikipedia.org/wiki/Bode_plot
Any help ?
16. Feb 19, 2016
### LvW
No - remember the simple RC lowpass with a pole at wp=1/RC. The decrease of amplitude with a corresponding phase shift will start already for f=1E-12 Hz (and even below). However, it will be hard to measure it. But that is not the question.
No - this is true for a first order lowpass only.
No - all the poles influence the amplitude and phase response also for very low frequencies, but this influence sometimes can be neglected.
Have a look on a 3rd-order or 4th-order transfer function. Why do you think that terms like w³T³ have no influence for very low frequencies?
Perhaps the influence is small - OK. But for your understanding it is important to know that there is an influence.
17. Feb 19, 2016
### LvW
Brainbaby - here are some additional information:
(1) There is a formula (called "BODE" integral), which has some relations to the "Hilbert transformation".
This formula exactly describes the relationship between the amplitude and phase response.
However, this formula is too complicated for writing it down at this place.
(2) For real (non-idealized) lowpass systems there is only one single frequency where the SLOPE is exactly -20 dB/Dec (-40 dB/Dec).
At this frequency the phase exactly assumes the value of -90 deg (-180 deg).
However - normally, this frequency is not known, but this knowlege is exploited for constructing a rough phase function curve based on the magnitude response (which also is known only as a approximation based on the pole location and the slope information about asymptotic lines).
Last edited: Feb 19, 2016
18. Feb 19, 2016
### brainbaby
In the above paragraph I was not talking about variation of amplitude with phase shift...rather I talked about variation of phase shift with frequency..
So you mean to say that the above conclusion is just an approximation ...however...it can be accepted on general terms....but may be rejected on precise basis....
19. Feb 19, 2016
### brainbaby
The reason why I said the above was because as the frequency grows along the graph phase shift accumulates ...and further ahead in frequency a pole exist...ok..and there an increase in phase shift is observed....and so on...
so they framed a theory based on experimental observation.....however in this thread what we have discussed so far is the "what"
and most probably Ive got what happened...now its time to know the "why".....and you have brought mother nature into consideration..
I appreciated that you worked out the maths....thanks for it...but that maths is just a representation of a phenomenon... what I believe is that
“When you understand something, then you can find the math to express that understanding. The math doesn't provide the understanding.”
and that understanding "why" is paramount for me.....
20. Feb 20, 2016
### LvW
As I have mentioned (BODE integral) gain (magnitude) and phase responses are correlated to each other
Similar Discussions: Phase shift issue in Dominant Pole Compensation strategy....
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https://codereview.stackexchange.com/questions/74868/triggering-approach-for-an-input-box
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# Triggering approach for an input box
I am setting a value to input box and trigger to hear the change. I would also like to always hear the input change, and for that I made this function.
Can any expert please verify the way I did is correct? Or is it further tune-able?
var page = function () {
return {
init : function () {
var input = $("#pNo");$(document).on("pageChange", this.onPageChange.bind(this));
$(input).val(1).trigger({type:'pageChange',element:input});$(input).bind("change paste keyup",function() { $.event.trigger({type: "pageChange", element:input})}); }, onPageChange : function (e) { console.log($(e.element).val());
}
}
}();
page.init();
Live Demo
## 1 Answer
My suggestion is to reduce the code:
var page = {
init: function(selector) {
$(selector).on('change paste keyup', page.onPageChange); }, onPageChange: function(e) { console.log($(e.target).val());
}
};
page.init('#pNo');
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http://mathoverflow.net/questions/12100/why-weil-group-and-not-absolute-galois-group?answertab=oldest
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# Why Weil group and not Absolute Galois group?
In many formulation of Class Field theory, the Weil group is favored as compared to the Absolute Galois group. May I asked why it is so? I know that Weil group can be generalized better to Langlands program but is there a more natural answer?
Also we know that the abelian Weil Group is the isomorphic image of the reciprocity map of the multiplicative group (in the local case) and of the idele-class group (in the global case). Is there any sense in which the "right" direction of the arrow is the inverse of the reciprocity map?
Please feel free to edit the question into a form that you think might be better.
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I have accepted the answer by Johnson but I still hope to receive the answer for the second part of the question. – Tran Chieu Minh Jan 17 '10 at 19:28
One reason we prefer the Weil group over the Galois group (at least in the local case) is that the Weil group is locally compact, thus it has "more" representations (over $\bf C$). In fact, all $\bf C$-valued characters of $Gal(\bar{\bf Q_p} / \bf Q_p)$ have finite image, where as that of $W_{\bf Q_p}$ can very well have infinite image. The same goes for general representations of these groups (recall that $\bf{GL}_n(\bf C)$ has no small subgroups.)
The global Weil group (which is much more complicated than the local one), on the other hand, is a rather mysterious object that is pretty much untouched in modern number theory as far as I can tell. Supposedly the global Langlands group used in the global Langlands correspondence should be the extension of the global Weil group by a compact group, but this is still largely conjectural.
The standard reference is Tate's "Number Theory Background" in the Corvallis volumes (available for free at ams.org). Also Brooks Roberts has notes on Weil representations available at his website.
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Thank you for the reply. Do you think it is possible to have a natural reason beside utility for which we prefer Weil group? – Tran Chieu Minh Jan 17 '10 at 19:17
Tran: Isn't utility one of the best motivators to do anything? – Adam Hughes Mar 22 '11 at 13:21
The Weil group appears for several reasons.
Firstly: if $K$ is a non-archimedean local field with residue field $k$, the local reciprocity law induces an embedding $K^{\times} \hookrightarrow G_K^{ab}.$ The image consists of all elements in $G_k$ whose image is an integral power of Frobenius. This is the abelianized Weil group; it just appears naturally.
Secondly: suppose that $K$ is a global field of positive characteristic, i.e. the function field of a curve over a finite field $k$. Then the global reciprocity map identifies the idele class group of $K$ with a subgroup of $G_K^{ab}$ consisting of elements which act on $k$ by integral powers of Frobenius. So again, it is the abelianized Weil group that appears.
Thirdly: suppose that $E$ is an elliptic curve over a quadratic imaginary field $K$ with complex multipliction by $\mathcal O$, the ring of integers in $K$. (Thus I am implicity fixing $K$ to have class number one, but this is not so important for what I am going to say next.) If $\ell$ is a prime, then the $\ell$-adic Tate module is then free of rank one over $\mathcal O\_{\ell}$ (the $\ell$-adic completion of $\mathcal O$), and the $G_K$-action on this Tate module induces a character $\psi_{\ell}:G_K^{ab} \rightarrow \mathcal O\_{\ell}^{\times}$.
There is a sense in which the various $\psi_{\ell}$ are indepenent of $\ell$, but what is that sense?
Well, suppose that $\wp$ is a prime of $K$, not dividing $\ell$ and at which $E$ has good reduction. Then the value of $\psi_{\ell}$ on $Frob_{\wp}$ is indepenent of $\ell$, in the sense that its value is an element of $\mathcal O$, and this value is independent of $\ell$. More generally, provided that $\wp$ is prime to $\ell$, the restriction of $\psi_{\ell}$ to the local Weil group at $\wp$ is independent of $\ell$ (in the sense that the value at a lift of Frobenius will be an algebraic integer that is independent of $\ell$, and its restriction to inertia at $\wp$ will be a finite image representation, hence defined over algebraic integers, which again is then independent of $\ell$).
Note that independence of $\ell$ doesn't make sense for $\psi\_{\ell}$ on the full local Galois group at $\wp$, since on this whole group it will certainly take values that are not algebraic, but rather just some $\ell$-adic integers, which can't be compared with one another as $\ell$ changes.
Now there is also a sense in which the $\psi\_\ell$, as global Galois characters, are indepdendent of $\ell$. Indeed, we can glue together the various local Weil group representations to get a representation $\psi$ of the global Weil group $W_K$. Since it is abelian, this will just be an idele class character $\psi$, or what is also called a Hecke character or Grossencharacter. It will take values in complex numbers. (At the finite places it even takes algebraic number values, but when we organize things properly at the infinite places, we are forced to think of it as complex valued.)
Note that $\psi$ won't factor through the connected component group, i.e. it won't be a character of $G_K^{ab}$. It is not a Galois character, but a Weil group character. It stores in one object the information contained in a whole collection of $\ell$-adic Galois characters, and gives a precise sense to the idea that these various $\ell$-adic characters are independent of $\ell$.
This is an important general role of Weil groups.
Fourthly: The Hecke character $\psi$ above will be an algebraic Hecke character, i.e. at the infinite places, it will involve raising to integral powers. But we can also raise real numbers to an arbitrary complex power $s$, and so there are Hecke characters that do not come from the preceding construction (or ones like it); in other words, there are non-algebraic, or non-motivic, Hecke characters. But they are abelian characters of the global Weil group, and they have a meaning; the variable $s$ to which we can raise real numbers is the same variable $s$ as appears in $\zeta$- or $L$-functions.
In summary: Because Weil groups are "less completed", or "less profinite", then Galois groups, they play an important role in describing how a system of $\ell$-adic representations can be independent of $\ell$. Also, they allow one to describe phenomena which are automorphic, but not motivic (i.e. which correspond to non-integral values of the $L$-function variable $s$). (They don't describe all automorphic phenomena, though --- one would need the entire Langlands group for that.)
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Excellent answer ! By the way, the second section of Gross-Reeder paper on arithmetic invariants (Duke 2010) is also nice for Weil groups – user4245 Jun 24 '12 at 16:56
Perhaps something worth pointing out, relating to how the Weil group appears naturally: it arises from a compatible system of group extensions at finite levels. Indeed, one of the "axioms" of class field theory, is the existence of a "fundamental class" uL/*K* in $H^2(\operatorname{Gal}(L/K),C_L)$ for each finite Galois extension $L/K$ (where $C_L$ is the class module). Each of these gives a group extension $$1\rightarrow C_L\rightarrow W_{L/K}\rightarrow \operatorname{Gal}(L/K)\rightarrow 1.$$ The projective limit of these gives the absolute Weil group fitting in $$1\rightarrow C\rightarrow W_K\rightarrow G_K$$ with the rightmost map having dense image (and $C$ is the formation module of the class formation). Thus, you can think of the Weil group as arising canonically out of the results of class field theory, thus making it a natural replacement of $G_K$ in questions related to CFT. I like section 1 of chapter III of Neukirch–Schmidt–Wingberg's Cohomology of number fields and the last chapter of Artin–Tate for this material.
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https://msoffice365exo.blogspot.com/2019/07/error-quarantinedattributevaluemustbeun.html
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### Recover Deleted items in Exchange online (Microsoft office 365)
In Exchange online we provide 3 layers of Recovery so that messages can be recovered Deleted Items Folder Recover Deleted Items Folder Purges Folder Deleted Items Folder When a mail is deleted(normal Delete not shift Delete) its moved to Deleted Items folder and its present there until, either we manually delete the messages from there or its deleted automatically as per the Retention Policy of the Organization(default value is 30 days) Recover Deleted Items Folder When a mail is Shift deleted(hard deleted), or deleted from Deleted items or removed from deleted items by the Retention policy, its moved to the Recover Deleted Items Folder and it remains there for next 14 days (can be extended to 30 days). There are 2 folders under Recovery Deleted Items Deleted Folder(its not the normal Deleted folder in the mailbox) Purges Folder When the mail is present in Recovery Deleted Items(Deleted folder) i
### Error - QuarantinedAttributeValueMustBeUnique
Case History.
2. Client wanted to setup SSO for office 365 users
Approach for requirement fullfilment
1. Deployed and configured Azure AD connect
95% users were synced and soft match was successfully done
5% users were getting error - QuarantinedAttributeValueMustBeUnique
When we checked 2 users were found under Active users
1. one in Cloud (this was created earlier/ already existed ) with active licenses and Mailbox
Solution -
but
If we delete the user in Azure we will loose the Email Data and if we delete the user in AD we will lose the profile on system.
However considering the above condition and in order to retain data and Profile too we had resolved using another work around.
1. Created a OU in AD “Non o365 sync”
2. Edited the Azure AD connect and stopped the above mentioned OU from syncing with Azure
3. Moved the users to this OU
4. This deleted the users in office 365, that were unlicensed and syncing with AD
5. Deleted the user from Office 365 recycle bin
6. Edited the Users UPN In AD and moved back to “Users” OU
7. Synced the users in office 365 identities mapped
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https://xianblog.wordpress.com/tag/xiao-li-meng/
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warp-U bridge sampling
Posted in Books, Statistics, Travel, University life with tags , , , , , , , , , , on October 12, 2016 by xi'an
[I wrote this set of comments right after MCqMC 2016 on a preliminary version of the paper so mileage may vary in terms of the adequation to the current version!]
In warp-U bridge sampling, newly arXived and first presented at MCqMC 16, Xiao-Li Meng continues (in collaboration with Lahzi Wang) his exploration of bridge sampling techniques towards improving the estimation of normalising constants and ratios thereof. The bridge sampling estimator of Meng and Wong (1996) is an harmonic mean importance sampler that requires iterations as it depends on the ratio of interest. Given that the normalising constant of a density does not depend on the chosen parameterisation in the sense that the Jacobian transform preserves this constant, a degree of freedom is in the choice of the parameterisation. This is the idea behind warp transformations. The initial version of Meng and Schilling (2002) used location-scale transforms, while the warp-U solution goes for a multiple location-scale transform that can be seen as based on a location-scale mixture representation of the target. With K components. This approach can also be seen as a sort of artificial reversible jump algorithm when one model is fully known. A strategy Nicolas and I also proposed in our nested sampling Biometrika paper.
Once such a mixture approximation is obtained. each and every component of the mixture can be turned into the standard version of the location-scale family by the appropriate location-scale transform. Since the component index k is unknown for a given X, they call this transform a random transform, which I find somewhat more confusing that helpful. The conditional distribution of the index given the observable x is well-known for mixtures and it is used here to weight the component-wise location-scale transforms of the original distribution p into something that looks rather similar to the standard version of the location-scale family. If no mode has been forgotten by the mixture. The simulations from the original p are then rescaled by one of those transforms, which index k is picked according to the conditional distribution. As explained later to me by XL, the random[ness] in the picture is due to the inclusion of a random ± sign. Still, in the notation introduced in (13), I do not get how the distribution Þ [sorry for using different symbols, I cannot render a tilde on a p] is defined since both ψ and W are random. Is it the marginal? In which case it would read as a weighted average of rescaled versions of p. I have the same problem with Theorem 1 in that I do not understand how one equates Þ with the joint distribution.
Equation (21) is much more illuminating (I find) than the previous explanation in that it exposes the fact that the principle is one of aiming at a new distribution for both the target and the importance function, with hopes that the fit will get better. It could have been better to avoid the notion of random transform, then, but this is mostly a matter of conveying the notion.
On more specifics points (or minutiae), the unboundedness of the likelihood is rarely if ever a problem when using EM. An alternative to the multiple start EM proposal would then be to get sequential and estimate the mixture in a sequential manner, only adding a component when it seems worth it. See eg Chopin and Pelgrin (2004) and Chopin (2007). This could also help with the bias mentioned therein since only a (tiny?) fraction of the data would be used. And the number of components K has an impact on the accuracy of the approximation, as in not missing a mode, and on the computing time. However my suggestion would be to avoid estimating K as this must be immensely costly.
Section 6 obviously relates to my folded Markov interests. If I understand correctly, the paper argues that the transformed density Þ does not need to be computed when considering the folding-move-unfolding step as a single step rather than three steps. I fear the description between equations (30) and (31) is missing the move step over the transformed space. Also on a personal basis I still do not see how to add this approach to our folding methodology, even though the different transforms act as as many replicas of the original Markov chain.
Cauchy Distribution: Evil or Angel?
Posted in Books, pictures, Running, Statistics, Travel, University life, Wines with tags , , , , , , , , , , , , on May 19, 2015 by xi'an
Natesh Pillai and Xiao-Li Meng just arXived a short paper that solves the Cauchy conjecture of Drton and Xiao [I mentioned last year at JSM], namely that, when considering two normal vectors with generic variance matrix S, a weighted average of the ratios X/Y remains Cauchy(0,1), just as in the iid S=I case. Even when the weights are random. The fascinating side of this now resolved (!) conjecture is that the correlation between the terms does not seem to matter. Pushing the correlation to one [assuming it is meaningful, which is a suspension of belief!, since there is no standard correlation for Cauchy variates] leads to a paradox: all terms are equal and yet… it works: we recover a single term, which again is Cauchy(0,1). All that remains thus to prove is that it stays Cauchy(0,1) between those two extremes, a weird kind of intermediary values theorem!
Actually, Natesh and XL further prove an inverse χ² theorem: the inverse of the normal vector, renormalised into a quadratic form is an inverse χ² no matter what its covariance matrix. The proof of this amazing theorem relies on a spherical representation of the bivariate Gaussian (also underlying the Box-Müller algorithm). The angles are then jointly distributed as
$\exp\{-\sum_{i,j}\alpha_{ij}\cos(\theta_i-\theta_j)\}$
and from there follows the argument that conditional on the differences between the θ’s, all ratios are Cauchy distributed. Hence the conclusion!
A question that stems from reading this version of the paper is whether this property extends to other formats of non-independent Cauchy variates. Somewhat connected to my recent post about generating correlated variates from arbitrary distributions: using the inverse cdf transform of a Gaussian copula shows this is possibly the case: the following code is meaningless in that the empirical correlation has no connection with a “true” correlation, but nonetheless the experiment seems of interest…
> ro=.999999;x=matrix(rnorm(2e4),ncol=2);y=ro*x+sqrt(1-ro^2)*matrix(rnorm(2e4),ncol=2)
> cor(x[,1]/x[,2],y[,1]/y[,2])
[1] -0.1351967
> ro=.99999999;x=matrix(rnorm(2e4),ncol=2);y=ro*x+sqrt(1-ro^2)*matrix(rnorm(2e4),ncol=2)
> cor(x[,1]/x[,2],y[,1]/y[,2])
[1] 0.8622714
> ro=1-1e-5;x=matrix(rnorm(2e4),ncol=2);y=ro*x+sqrt(1-ro^2)*matrix(rnorm(2e4),ncol=2)
> z=qcauchy(pnorm(as.vector(x)));w=qcauchy(pnorm(as.vector(y)))
> cor(x=z,y=w)
[1] 0.9999732
> ks.test((z+w)/2,"pcauchy")
One-sample Kolmogorov-Smirnov test
data: (z + w)/2
D = 0.0068, p-value = 0.3203
alternative hypothesis: two-sided
> ro=1-1e-3;x=matrix(rnorm(2e4),ncol=2);y=ro*x+sqrt(1-ro^2)*matrix(rnorm(2e4),ncol=2)
> z=qcauchy(pnorm(as.vector(x)));w=qcauchy(pnorm(as.vector(y)))
> cor(x=z,y=w)
[1] 0.9920858
> ks.test((z+w)/2,"pcauchy")
One-sample Kolmogorov-Smirnov test
data: (z + w)/2
D = 0.0036, p-value = 0.9574
alternative hypothesis: two-sided
Posterior predictive p-values and the convex order
Posted in Books, Statistics, University life with tags , , , , , , , , , on December 22, 2014 by xi'an
Patrick Rubin-Delanchy and Daniel Lawson [of Warhammer fame!] recently arXived a paper we had discussed with Patrick when he visited Andrew and I last summer in Paris. The topic is the evaluation of the posterior predictive probability of a larger discrepancy between data and model
$\mathbb{P}\left( f(X|\theta)\ge f(x^\text{obs}|\theta) \,|\,x^\text{obs} \right)$
which acts like a Bayesian p-value of sorts. I discussed several times the reservations I have about this notion on this blog… Including running one experiment on the uniformity of the ppp while in Duke last year. One item of those reservations being that it evaluates the posterior probability of an event that does not exist a priori. Which is somewhat connected to the issue of using the data “twice”.
“A posterior predictive p-value has a transparent Bayesian interpretation.”
Another item that was suggested [to me] in the current paper is the difficulty in defining the posterior predictive (pp), for instance by including latent variables
$\mathbb{P}\left( f(X,Z|\theta)\ge f(x^\text{obs},Z^\text{obs}|\theta) \,|\,x^\text{obs} \right)\,,$
which reminds me of the multiple possible avatars of the BIC criterion. The question addressed by Rubin-Delanchy and Lawson is how far from the uniform distribution stands this pp when the model is correct. The main result of their paper is that any sub-uniform distribution can be expressed as a particular posterior predictive. The authors also exhibit the distribution that achieves the bound produced by Xiao-Li Meng, Namely that
$\mathbb{P}(P\le \alpha) \le 2\alpha$
where P is the above (top) probability. (Hence it is uniform up to a factor 2!) Obviously, the proximity with the upper bound only occurs in a limited number of cases that do not validate the overall use of the ppp. But this is certainly a nice piece of theoretical work.
XL definition of statistics in 24″
Posted in Books, Kids, Statistics, University life with tags , , , on September 22, 2013 by xi'an
Z-test, t-test, chi-squared test,
Bayes, Frequentist, Fiducial
Let me make you feel influential
Regression, Correlation, Causation,
What else can generate more passion?
Skewness, Kurtosis, Heteroscedasticity
Boy, do I feel sexy?
Xiao-Li Meng, at the Ig Nobel ceremony
XL for 24/7 fame at (Ig) Nobel
Posted in Kids, Statistics, University life with tags , , , on September 12, 2013 by xi'an
Tonight, our friend Xiao-Li Meng will (no doubt brilliantly) deliver a 24/7 lecture at the Ig Nobel Prize ceremony. It will be webcast live, with a watching party in Paris…. (A wee too late for me, I am afraid.) Although Xiao-Li is quite able to lecture 24/7 on statistics, this special lecture will last 24 seconds plus 7 words. Bets are open for the 7 words!! (Note that, contrary to the other Nobel Prize, the Ig Nobel Prizes often include winners in mathematics and statistics.)
estimating the measure and hence the constant
Posted in pictures, Running, Statistics, University life with tags , , , , , , , on December 6, 2012 by xi'an
As mentioned on my post about the final day of the ICERM workshop, Xiao-Li Meng addresses this issue of “estimating the constant” in his talk. It is even his central theme. Here are his (2011) slides as he sent them to me (with permission to post them!):
He therefore points out in slide #5 why the likelihood cannot be expressed in terms of the normalising constant because this is not a free parameter. Right! His explanation for the approximation of the unknown constant is then to replace the known but intractable dominating measure—in the sense that it cannot compute the integral—with a discrete (or non-parametric) measure supported by the sample. Because the measure is defined up to a constant, this leads to sample weights being proportional to the inverse density. Of course, this representation of the problem is open to criticism: why focus only on measures supported by the sample? The fact that it is the MLE is used as an argument in Xiao-Li’s talk, but this can alternatively be seen as a drawback: I remember reviewing Dankmar Böhning’s Computer-Assisted Analysis of Mixtures and being horrified when discovering this feature! I am currently more agnostic since this appears as an alternative version of empirical likelihood. There are still questions about the measure estimation principle: for instance, when handling several samples from several distributions, why should they all contribute to a single estimate of μ rather than to a product of measures? (Maybe because their models are all dominated by the same measure μ.) Now, getting back to my earlier remark, and as a possible answer to Larry’s quesiton, there could well be a Bayesian version of the above, avoiding the rough empirical likelihood via Gaussian or Drichlet process prior modelling.
lemma 7.3
Posted in Statistics with tags , , , , , , , , , , , on November 14, 2012 by xi'an
As Xiao-Li Meng accepted to review—and I am quite grateful he managed to fit this review in an already overflowing deanesque schedule!— our 2004 book Monte Carlo Statistical Methods as part of a special book review issue of CHANCE honouring the memory of George thru his books—thanks to Sam Behseta for suggesting this!—, he sent me the following email about one of our proofs—demonstrating how much efforts he had put into this review!—:
I however have a question about the proof of Lemma 7.3
on page 273. After the expression of
E[h(x^(1)|x_0], the proof stated "and substitute
Eh(x) for h(x_1)". I cannot think of any
justification for this substitution, given the whole
purpose is to show h(x) is a constant.
I put it on hold for a while and only looked at it in the (long) flight to Chicago. Lemma 7.3 in Monte Carlo Statistical Methods is the result that the Metropolis-Hastings algorithm is Harris recurrent (and not only recurrent). The proof is based on the characterisation of Harris recurrence as having only constants for harmonic functions, i.e. those satisfying the identity
$h(x) = \mathbb{E}[h(X_t)|X_{t-1}=x]$
The chain being recurrent, the above implies that harmonic functions are almost everywhere constant and the proof steps from almost everywhere to everywhere. The fact that the substitution above—and I also stumbled upon that very subtlety when re-reading the proof in my plane seat!—is valid is due to the fact that it occurs within an integral: despite sounding like using the result to prove the result, the argument is thus valid! Needless to say, we did not invent this (elegant) proof but took it from one of the early works on the theory of Metropolis-Hastings algorithms, presumably Luke Tierney’s foundational Annals paper work that we should have quoted…
As pointed out by Xiao-Li, the proof is also confusing for the use of two notations for the expectation (one of which is indexed by f and the other corresponding to the Markov transition) and for the change in the meaning of f, now the stationary density, when compared with Theorem 6.80.
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https://arxiv.org/abs/1805.08277
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astro-ph.SR
(what is this?)
# Title:Gaia DR2 reveals a very massive runaway star ejected from R136
Abstract: A previous spectroscopic study identified the very massive O2 III star VFTS 16 in the Tarantula Nebula as a runaway star based on its peculiar line-of-sight velocity. We use the Gaia DR2 catalog to measure the relative proper motion of VFTS 16 and nearby bright stars to test if this star might have been ejected from the central cluster, R136, via dynamical ejection. We find that the position angle and magnitude of the relative proper motion (0.338 +/- 0.046 mas/yr, or approximately 80 +\- 11 km/s) of VFTS 16 are consistent with ejection from R136 approximately 1.5 +/- 0.2 Myr ago, very soon after the cluster was formed. There is some tension with the presumed age of VFTS 16 that, from published stellar parameters, cannot be greater than 0.9 +0.3/-0.2 Myr. Older ages for this star would appear to be prohibited due to the absence of He I lines in its optical spectrum, since this sets a firm lower limit on its effective temperature. The dynamical constraints may imply an unusual evolutionary history for this object, perhaps indicating it is a merger product. Gaia DR2 also confirms that another very massive star in the Tarantula Nebula, VFTS 72 (alias BI253; O2 III-V(n)((f*)), is also a runaway on the basis of its proper motion as measured by Gaia. While its tangential proper motion (0.392 +/-0.062 mas/yr or 93 +/-15 km/s) would be consistent with dynamical ejection from R136 approximately 1 Myr ago, its position angle is discrepant with this direction at the 2$σ$ level. From their Gaia DR2 proper motions we conclude that the two ~100 solar mass O2 stars, VFTS 16 and VFTS72, are fast runaway stars, with space velocities of around 100 km/s relative to R136 and the local massive star population. The dynamics of VFTS16 are consistent with it having been ejected from R136, and this star therefore sets a robust lower limit on the age of the central cluster of ~1.3 Myr.
Comments: Version 2 is now accepted by A&A with minor updates from V1 Subjects: Solar and Stellar Astrophysics (astro-ph.SR) Journal reference: A&A 619, A78 (2018) DOI: 10.1051/0004-6361/201833465 Cite as: arXiv:1805.08277 [astro-ph.SR] (or arXiv:1805.08277v2 [astro-ph.SR] for this version)
## Submission history
From: Daniel J. Lennon [view email]
[v1] Mon, 21 May 2018 20:06:18 UTC (5,867 KB)
[v2] Tue, 24 Jul 2018 08:52:59 UTC (5,918 KB)
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http://atlas.math.umd.edu/software/documentation/atlasofliegroups-docs/windows_installation.html
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# Windows¶
The options, in order of preference, are:
## Compiling¶
The best option is available on Windows 10. This is the bash shell, which is available (currently in beta version) in Windows 10. It provides a linux command line environment. This was produced by Canonical, the makers of Ubuntu, so it is very close to an Ubuntu linux environment.
On older Windows machines linux software can be run using Installing under Cygwin. Unless you have already installed Cygwin and are familiar with it this is not recommended.
### Step-by-Step installation using the bash shell¶
If you haven’t done so already, install the bash shell following the instructions from the Microsoft bash shell page. We also recommend these instructions from How-To Geek.
Open a bash window.
Install some necessary software. After the first call of sudo apt-get install you need to type your password. (Depending on how you installed the bash shell you might not need to use sudo.):
sudo apt-get install git
sudo apt-get install make
sudo apt-get install g++
sudo apt-get install bison
sudo apt-get install emacs (or your favorite text editor)
The remainder of the process follows the standard linux process. See Linux (and Solaris) for details. Briefly:
Version 1.0.5 atlas_1.0.5.tgz source code for Fokko and atlas including messages and atlas-scripts
Unpack the file:
tar xvf atlas_1.0.5.tgz
Go into the proper directory and type make:
cd atlasofliegroups
make
Follow the instructions in Linux (and Solaris).
#### Installing under Cygwin¶
Install cygwin: Double-click on setup.exe to run it. At the package menu choose at least the following packages:
• gcc/g++ (version 4x)
• make
• bison
• libncurses-devel
• libstdc++6-devel
• git
Next, open a cygwin terminal by double-clicking on the icon. You are now in a linux-like environment.
The remainder of the process follows the standard linux process, similar to the procedure under bash. See Linux (and Solaris) for details.
## Using Docker¶
The preferred method is to compile the software from source.
The next choice is using the Docker container system.
This installs a container, which is a self-contained linux environment (similar to a virtual machine) and runs the software in the container. This is less dependent on the details of your system, and is a good option of you have trouble compiling the software yourself. It requires adminsitrative privileges, so is mainly used for personal machines, and not instutional machines under the control of a system administrator.
Install docker (community version) for your system from https://www.docker.com/community-edition Double click on the file to install it. This requires typing your password.
Open a command window and give the command
to download the software and run it (it launches atlas and read in the fill all.at). The first time you do this it takes up to a few minutes. Subsequent times it is much faster.
The best method is to compile from source. As a backup option you can download and install an executable file.
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https://space.stackexchange.com/questions/35678/what-is-propulsive-passivation-and-why-will-the-spacex-stp-2-mission-do-it?noredirect=1
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# What is “propulsive passivation” and why will the SpaceX STP-2 mission do it?
The Teslarati article SpaceX’s Falcon Heavy flies a complex mission for the Air Force in launch video discusses the upcoming third Falcon Heavy mission STP-2 and quotes the caption on the linked SpaceX video:
The STP-2 mission will be among the most challenging launches in SpaceX history with four separate upper-stage engine burns, three separate deployment orbits, a final propulsive passivation maneuver and a total mission duration of over six hours. [It] will demonstrate the capabilities of the Falcon Heavy launch vehicle and provide critical data supporting certification for future National Security Space Launch (NSSL) missions. In addition, [the USAF] will use this mission as a pathfinder for the [military’s systematic utilization of flight-proven] launch vehicle boosters.
SpaceX, April 2019
The SpaceX (unlisted?) video linked in the article STP-2 Animation shows a final propulsive passivation step but does not show what happens because of it.
Question: What is "propulsive passivation" and why will the SpaceX STP-2 mission do it?
• – uhoh Apr 21 at 1:55
I believe the term 'a final propulsive passivization maneuver' is in direct contradiction to the oft referenced 'non propulsive vent' used in other spacecraft at times. A non-non-propulsive vent, so to speak.
A non propulsive vent balances orifices so no propulsion occurs, this may be important in scenarios where the upper stage has been placed in a very particular trajectory (either a graveyard parking orbit or a safe entry point) and now must passivate itself without changing this trajectory.
A propulsive passivization maneuver seems to intend to change the trajectory. Since the final DSX payload is being delivered to a medium Earth orbit, I believe the intent is to reduce the time before decay while saving on an additional engine relight - with 4 relights already built into the mission there is a lot of starting fluid used and many cycles on the engine, meaning there may be cost, mass and safety reasons to avoid another relight.
By coasting (presumably) to apoapsis and then venting residual pressure through the engine chamber and bell, they can produce a low risk controlled thrust to lower the orbit and speed decay.
• I have a hunch this is exactly the correct answer. It's a non-non-propulsive passivation maneuver. Bingo! – uhoh Apr 21 at 16:10
GTO orbits are too far to send the vehicle back to earth for re-entry and to burn off in the atmosphere. So the second stage will become another dead satellite, like many other boosters and rockets up there. For all objects that are past their usage stage, whether a 15 year old satellite or a six hours old second/third stage rocket, the (french) latest law/treaty of operating in space asks from all those vehicles to do a passivation of any liquid or electrical energy, so as they become space junk, they become a less dangerous junk. Any electrical energy in the batteries is depleted (disco lights for a night??lol) and any liquid from fuel or pressure tanks is vented. The remaining object is empty from any hazard that could see it exploding at its last orbits, which could last years
• This is a really nice, concise answer. Thanks! – uhoh May 22 at 16:07
...spent upper stages are generally passivated after their use as a launch vehicle is complete in order to minimize risks while the stage remains derelict in orbit.[5] Passivation means removing any sources of stored energy remaining on the vehicle, as by dumping fuel or discharging batteries.
• Okay that's a start, but "What is “propulsive passivation” and why will the SpaceX STP-2 mission do it?" If you can add an explanation of the specific term “propulsive passivation” and some kind of explanation why SpaceX is passivating propulsively, that would be great! – uhoh Apr 21 at 3:26
• @uhoh I guess you're reading this wrong. It's not 'passivating propulsively' but 'passivating the propulsive system', i.e. discarding all remaining propellants. In "a final propulsive passivation maneuver" the 'propulsive' connects to passivation, not to maneuver. – asdfex Apr 21 at 10:09
• @asdfex I guess I am not reading it wrong. I am reading the two word phrase as adjective, noun and I don't see any other way to read this phrase. SpaceX is a US company and can be expected to get their English correct, so I am going to assume they mean what they said, and what they said was propulsive passivation. – uhoh Apr 21 at 10:11
• @uhoh you can read it as "a final, propulsive-passivation maneuver" or as "a final, propulsive, passivation maneuver" Both are valid. – asdfex Apr 21 at 10:21
• @asdfex For the first one, that would have to be written as "a final, propulsion-passivation maneuver" to be what you want it to be. For the second one, that is exactly what I am saying it is! It is a propulsive maneuver for the purposes of passivation. fun: 1, 2, 3, 4, 5, 6 – uhoh Apr 21 at 10:23
The original text states
a final propulsive passivation maneuver
This is ambiguous as it can be read in two ways:
• "a final propulsive-passivation maneuver" - a final maneuver that does passivation of the propulsive system.
• "a final, propulsive, passivation maneuver" - a final passivation maneuver that is propulsive.
It's not obvious from the text which of the two interpretations is the intended one, but I'm very much in favor of the first one.
It should be noted that any passivation that consists of discarding propellant will be at least slightly propulsive, as is every action that expels material from a spacecraft. On the other hand, I'm very sure that this is not the intended meaning here.
• Thanks for your answer. For the record, I have respectfully disagreed (1 2) with the first interpretation. I believe that it would have to be "propulsion passivation", not "propulsIve passivation" for that to be a correct interpretation. – uhoh Apr 21 at 10:39
• Then again, I believed this was serious, so... – uhoh Apr 21 at 10:45
• But +1 because the graphics in the video (screen shot in the question) seem to show cold propellant being vented out the nozzle rather than exhaust from a started engine producing significant propulsion, That seems to argue strongly in favor of the first one (your favorite). – uhoh Apr 21 at 10:51
The video portion captioned "Propulsive Passivation" appears to answer the question by 2 noteworthy observations. First, the exhaust nozzle is venting propellant to space - the "Passivation" part. This is confirmed by the absence of any flames at the rocket's exhaust. Second, the propellant is expelled under pressure (as opposed to "free" venting) - which accounts for the "Propulsive" part. Since the word "Propulsive" by definition means driving or pushing forward, perhaps a more appropriate caption might have read: "Pressurized Passivation".
• If there was no pressure, how would venting occur? – Organic Marble May 22 at 14:52
PP is to vent the propellant from the spacecraft to prevent it exploding which could cause clouds of debris that can potentially damage other satellites. (https://en.wikipedia.org/wiki/Passivation_(spacecraft)).
It's a routine in modern rocket launches since debris issues are getting more severe and could harbor bigger disasters if there's a 'bomb' like spacecraft floating in space after the mission. STP-2 has some buffers in the fuel tank to provide contingency usages(like re-deployment if failed). The unused fuel should be passivated by burning it at a slower speed but until fully exhausted.
• Hi and welcome to Space Exploration SE. Unfortunately, your answer doesn't seem to provide anything that wouldn't be already covered by the other answers here. It'd also be best to address the second part of the question about why was a "propulsive" passivation chosen. – TooTea Jun 18 at 16:51
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https://www.khanacademy.org/math/linear-algebra/vectors-and-spaces/vectors/e/adding-vectors-in-magnitude-and-direction-form
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Add vectors: magnitude & direction to component
Add two vectors in magnitude and direction form to get a new vector in component form.
Problem
The magnitude of v, with, vector, on top is 6, and its direction angle is 160, degree.
The magnitude of w, with, vector, on top is 4, and its direction angle is 290, degree.
Find the component form of v, with, vector, on top, plus, w, with, vector, on top.
It's okay to round your intermediate calculations and final answer to the nearest hundredth.
v, with, vector, on top, plus, w, with, vector, on top, approximately equals, left parenthesis, space
space, comma
right parenthesis, space
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https://optionrsdt.web.app/gennusa59758tiwy/annual-percentage-yield-nominal-rate-bamo.html
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## Annual percentage yield nominal rate
31 Aug 2019 The nominal interest rate is the interest rate before taking inflation into account, in contrast to real interest rates and effective interest rates. more.
As the effective interest rate is referred to as APY, annual percentage yield. Again , sometimes in finance, you can find different terminologies used for nominal and When a large amount of money is involved, the difference between the nominal rate and EAR makes a significant difference. Answer and Explanation: The formula *APY is the Annual Percentage Yield. Fees may reduce earnings on accounts. CERTIFICATES/IRA CERTIFICATES (\$10,000 or more). Nominal Rate. You should check with your financial institution to find out how often interest is being compounded on your particular investment. Yearly APY. Annual percentage Free calculator to find the total interest, end balance, and the growth chart of a maturity periods of CDs, especially their annual percentage yields (APY). Account, Nominal Rate, Annual Percentage Yield * Annual percentage yield ( APY) is based on interest being paid quarterly and that interest remains on We therefore need a way of comparing interest rates. For example, is an annual interest rate of $$\text{8}\%$$ compounded quarterly higher or lower than an interest
## How to calculate annual percentage yield. The calculation of the annual percentage yield is based on the following equation: APY = (1 + r/n ) n – 1 . where: r - the interest rate. n - the number of times the interest is compounded per year.
23 Jan 2015 This APY calculator estimates the annual percentage yield value by considering the nominal interest rate and the compounding frequency 5 Feb 2019 Saving Account Annual nominal interest rate - 5% Annual percentage yield ( APY) less tax on income, calculated at 5% annual interest rate, 23 Jun 2007 Their savings account interest rate is quoted as being 5.05% APY. Their actual APR, though, is roughly 4.93% – the monthly compounding is 14 Sep 2016 If a principal is invested at the annual (nominal) rate r compounded continuously, then the annual percentage yield is. AP Y = e r - 1. Example 5. The annual percentage yield (APY) is the real rate of return earned on a savings deposit or investment taking into account the effect of compounding interest. Unlike simple interest, compounding interest is calculated periodically and the amount is immediately added to the balance. Often abbreviated as APY, the Annual Percentage Yield is a relevant financial indicator on savings account that helps in comparing the interest rates that have different compounding intervals. It is often called as Effective Annual Rate (EAR).
### Let's come up with a formula to work out the Effective Annual Rate if we know: the rate mentioned (the Nominal Rate, "r"); how many times it is compounded ("n").
17 Oct 2019 Between compounding interest on a daily or monthly basis, daily compounding gives a higher yield - although the Look for the advertised APY. 1 Feb 2020 Term, Min Balance, Nominal Rate, APY* The annual percentage yield is based on an assumption that dividends will remain in the account First enter the APY in percent. Some banks also refer to this as the effective annual rate (EAR). Next enter how frequently interest compounds each year. Common
### 12 Jun 2019 Savings Accounts, Dividend Rate, Annual Percentage Yield (APY) Term, Nominal Rate, APY*, Minimum Balance to Open and Earn Stated
i(m) . . . nominal (annual) interest rate compounded (convertible, payable) m times per year It is also known as the annual percentage yield(APY). Then, i(m) m. to get a clear picture of the loan's true cost or the investment's true yield. annual percentage yield, annual percentage rate, effective rate, nominal rate, and
## The difference between the two is that the nominal rate does not take the compounding into consideration, while the effective annual yields take the effect of
14 Apr 2019 Annual percentage rate (APR) (also called nominal interest rate) is the annualized interest rate on a loan or investment which does not account 23 Jan 2015 This APY calculator estimates the annual percentage yield value by considering the nominal interest rate and the compounding frequency 5 Feb 2019 Saving Account Annual nominal interest rate - 5% Annual percentage yield ( APY) less tax on income, calculated at 5% annual interest rate, 23 Jun 2007 Their savings account interest rate is quoted as being 5.05% APY. Their actual APR, though, is roughly 4.93% – the monthly compounding is 14 Sep 2016 If a principal is invested at the annual (nominal) rate r compounded continuously, then the annual percentage yield is. AP Y = e r - 1. Example 5. The annual percentage yield (APY) is the real rate of return earned on a savings deposit or investment taking into account the effect of compounding interest. Unlike simple interest, compounding interest is calculated periodically and the amount is immediately added to the balance. Often abbreviated as APY, the Annual Percentage Yield is a relevant financial indicator on savings account that helps in comparing the interest rates that have different compounding intervals. It is often called as Effective Annual Rate (EAR).
First enter the APY in percent. Some banks also refer to this as the effective annual rate (EAR). Next enter how frequently interest compounds each year. Common
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https://competitive-exam.in/questions/discuss/in-order-to-avoid-tendency-of-separation-at
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4
# In order to avoid tendency of separation at throat in a Venturimeter, the ratio of the diameter at throat to the diameter of pipe should be
1/16 to 1/8
1/8 to 1/4
1/4 to 1/3
1/3 to 1/2
Please do not use chat terms. Example: avoid using "grt" instead of "great".
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https://nips.cc/Conferences/2015/ScheduleMultitrack?event=5554
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Timezone: »
Poster
Non-convex Statistical Optimization for Sparse Tensor Graphical Model
Wei Sun · Zhaoran Wang · Han Liu · Guang Cheng
Wed Dec 09 04:00 PM -- 08:59 PM (PST) @ 210 C #79 #None
We consider the estimation of sparse graphical models that characterize the dependency structure of high-dimensional tensor-valued data. To facilitate the estimation of the precision matrix corresponding to each way of the tensor, we assume the data follow a tensor normal distribution whose covariance has a Kronecker product structure. The penalized maximum likelihood estimation of this model involves minimizing a non-convex objective function. In spite of the non-convexity of this estimation problem, we prove that an alternating minimization algorithm, which iteratively estimates each sparse precision matrix while fixing the others, attains an estimator with the optimal statistical rate of convergence as well as consistent graph recovery. Notably, such an estimator achieves estimation consistency with only one tensor sample, which is unobserved in previous work. Our theoretical results are backed by thorough numerical studies.
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https://forums.bistudio.com/tags/audio/
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# Search the Community
Showing results for tags 'audio'.
• ### Search By Tags
Type tags separated by commas.
### Forums
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Found 16 results
3. ## Audio Tweaking (dev branch)
The audio changes which delayed Development branch updates are now partly published. As with most of these large tasks, this is ongoing work and so the current state is not considered final (in some places it may be worse for a little while). Effectively the core foundations are in place and now each individual asset needs tuning and fixing. We feel it will improve the soundscape in the final game :622: Senior audio team member Ondřej Matějka goes over the details:
4. ## Forcing audio volume settings on players
Hey all, I am currently preparing a mission which will feature a background music and ambient sounds. I would like to make sure that all the players hear it in case any of them had the music settings turned down to 0%. Is there any way to force audio volume settings on the players via a script or some addon so that I would be sure they can hear the music? Cheers, Adam
Hi. How can I send some audio message in group channel, like "Get in that vehicle"? Edit: I mean just play a sound, no groupchat or action.
6. ## Audio Static w/ Massive Frame Drop
Hey guys, So I have a glitch where whenever I am in a helicopter, vehicles, or a very tight area (like buildings or places with lots of echo) there is a loud static and "popping" sounds followed by a massive drop in frames. The glitch will go away if in 3rd person or in 32 bit arma, but I would like to be able to use 64 bit arma. I would like to elaborate on my term of massive frame rate drops, my frames will go from 60, all the way down to 1 or it will freeze entirely, so it makes first person unplayable. I have tested increasing sound sources from highest to lowest with no fix, I have tried most everything under the sun. People say that this issue is a Logitech headset only issue and I can confirm that that is false to an extent. I use Corsair VOID gaming USB headset and this issue persists. I have had this glitch for at least 6 months. Hardware: AMD FX-8350 (CPU) ASUS 970 PRO gaming AURA (Mobo) G.Skill Ripjaw DDR3 2x8 Gb RAM (RAM sticks) ASUS GTX 970 STRIX (GPU) Corsair VOID gaming USB Headset (Headset) (8 channel, 16 bit, 48000 Hz) (It is stuck on that setting btw) Thank you for taking the time to read.
7. ## All sound from PC cuts out when i launch arma
Everytime i launch Arma 3, when i press play on the launcher, or launch from the arma 3 folder in steamapps, all sound on my system cuts out. Discord, youtube, anything, including the game just cuts out. I am not sure what causes this bug, but it is very annoying as i can't play the game (Unless i want to play without sound). What i also find wierd is that i have to then close and reopen apps such as discord to hear and to make my mic work, it mutes my mic.
8. ## An Annoying Audio Bug
Hello there great community of Arma! I happened to experience this strange audio bug during my last sessions of Arma, and I'd like to ask, if anyone else experienced something familiar, and if so, did anyone managed to fix it. Here's the video of bug, it'll be better than making an effort to explain it with words: I'm using Dynasound+Enhanced Soundscape, and I feel that it started to happen more frequently after recent updates of Arma.
9. ## Audo Language of character
Hey all- TL;DR - Character _was_ speaking English, then last night when I went to play character was speaking French. Halp! So I've played the Arma series off and on over the years and I seem to remember running into this issue some years ago in Arma 2, but can't for the life of me find a setting to have "ALL" audio as English only. IIRC, in A2 there was a setting that had to be set for your character as well as the AI units to speak English in the voice over. Somehow, that has been set correctly on Arma 3 on my machine since I downloaded it day 1, but yesterday it got switched? Relevant info: Playing Antistasi - Warlords of the Pacific (Playing as independent) Mods: CBA_A3 ; Dynasound 2.0 Sunday: First day back and playing, char speaking English calling targets, regroup etc. Monday: Log back in, char speaking French calling targets, regroup etc.
10. ## Very weird sound problem with the Logitech G430
Hello there, I bought a new Logitech G430 Headset today and I have a very weird problem: Whenever I drive a car in first person, my frame-rate drops to one or two and the screen starts to freeze. This is ONLY in Arma 3, ONLY in First Person and ONLY in Cars. I don't know whats wrong but since I frequently drive cars in Arma and also in First-Person it's really annoying, especially when I'm forced to first person and driving alone it makes the game unplayable. I tried various stuff that may fix this but nothing worked yet. Any Ideas or where I could continue troubleshooting? CPU: AMD FX-8320E Mainboard: ASRock 990FX Extreme6 GPU: AMD Radeon R9 390 Headset: Logitech G430 OS: Windows 10 64-bit
11. ## Grenade pin pulling sound not working?
Hello. I'm trying to make the grenades play a pin pulling sound when you throw them. This is what I have: But for some reason it doesn't seem to be playing. Can anyone spot something wrong here or help me out?
13. ## No sound after joining server
Hello, I just bought arma 3 and i started playing the campain and everything was fine but then when i went into the multiplayer i joined a server and lost all the sound (menu music, sfx ...) i then disconected frome the server but the sound didn't come back and i had to restart arma to regain the audio... I tried changing the cpu count and all but nothing changed and it does it on every server ... I loved arma 2 especially for it's multiplayer :wub: and now arma 3 looks epic but i can't experience it without any audio! Anyone know how i can fix this ? <_<
14. ## [Feedback] Distant gunshots are still pretty bad
While the not-so-recent sound update dramatically improved the quality of sounds, especially gunshots, in ArmA3 by adding a very nice dynamic echoing system, the actual gunshots of certain weapons still feel very lackluster. In particular, one of the biggest problems (in my opinion) is the sound of heavier weapons. While the marksman DLC gpmg's sound okay, most of the other weapons, including the vanilla .50 HMG and the GMG sound... less terrifying than they should. I'd like to use an example of what I consider to be one of the best heavy weapons sound effects system, the ArmA2 mod ACEX_SM. If you want an example, the following link contains some audio from ArmA2's acex_sm sound mod. The heavier weapons are more deep and sonorous, and you can EASILY tell the direction in which they are firing from, even with youtube's stereo audio compression. You only need to listen for a few moments for this to become abundantly clear. In comparison, ArmA3's lmgs and hmgs sound considerably more ambiguous. The sound of the supersonic rounds snapping overhead is excellent, but the attenuation of the source gunshots is unrealistically exaggerated. It takes a significant amount of experience for a player to estimate which direction they are being fired at from, and even then, visual cues are vital in determining the source. As an example; I note that this is a particularly poor example, as I am unsure of the nature of the weapon being used to fire at the soldier in cover, however, it's quite clear that the snaps dramatically overwhelm the audio of the weapon being fired. Also, the snaps are the same in sound regardless of the caliber of weapon being fired. (A 40mm cannon round whizzing overhead sounds identical to a 5.56). The source of the shots cannot be audibly gauged. Credits to ShackTactical and Dslyecxi for the footage. I used it in the context of education and feedback, I'm sure they won't mind.
15. ## Audio Crackling
Hello! While playing Arma 3 I noticed strange crackling/popping noises in the menu and in-game when there were a lot of background sounds around (e.g. driving a car offroad). I found a video of someone else on YouTube who had the same issue: Arma 3- Crackling and Popping Audio - YouTube ​I originally thought that this was related to some driver of mine causing dpc latency spikes. According to LatencyMon it indeed was. I updated all my drivers, my BIOS, changed power plan settings, and I even did a clean install of the OS and I still haven't gotten to the bottom of this. But just to make sure, I installed Arma 3 on a second pc and it had the same audio glitches (and latency Spikes). The only connection I could imagine would be Windows 10, which I installed on both machines. I am puzzled as to how this is even possible so my best guess is that it must be a compatibility problem. Is there anyone else here who is experiencing audio popping during gameplay and has Windows 10 installed? Thanks for the help​
16. ## Getting two errors when trying to start server, quick fixes.
I've troubleshooted so much today it's amazing. So here we go - Quick and easy. Issue #1: jordan@jordanserver:~/arma2arrowhead$sudo ./arma2oaserver check ArmA 2 directory: OK Server executable: /server ERROR! Port number: 2302 Config file: OK PID file: /2302.pid RUN file: /2302.run Issue #2: jordan@jordanserver:~/arma2arrowhead$ ./server Data file too short '/home/jordan/arma2arrowhead/pmc\addons\ca_pmc.pbo'. Expected 1234612782 B, got 115987 B Segmentation fault (core dumped)
×
• Clubs
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http://www.carlellis.co.uk/category/ruby/
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## Stripe CTF 3.0
Sadly, level 3 would not run for me, even with Stripe’s patch, so I could not continue with the competition. It was fun while it lasted though – C
Wednesday saw the beginning of another Stripe CTF! This time I was in London when it started so I went to the launch meeting with some old uni friends.
The theme this time was distributed computation, so with a tiny netbook, I dove in to the levels.
## Level 0
Level 0 was essentially an exercise in optimisation. A given text input was checked against a list of words. If an input word was in the preset dictionary, it had to be tagged. The preset dictionary was an ordered list, and as such was O(n) to search. By applying the following:
```index 1558f2d..d07273f 100644
--- orig.rb
+++ mod.rb
@@ -1,4 +1,5 @@
#!/usr/bin/env ruby
+require 'set'
# Our test cases will always use the same dictionary file (with SHA1
# 6b898d7c48630be05b72b3ae07c5be6617f90d8e). Running `test/harness`
@@ -7,6 +8,7 @@
path = ARGV.length > 0 ? ARGV[0] : '/usr/share/dict/words'
+entries = Set.new(entries)
output = contents.gsub(/[^ n]+/) do |word|```
The list is turned into a set with a O(1) lookup time. Significantly speeding up the operation.
## Level 1
This level was about cryptocurrencies, and to pass this level you had to mine a … ‘GitCoin’. Essentially, you were given a repo with an initial catalog of transactions. You had to successfully submit a transaction with gave your given use a gitcoin.
Proof of work for a gitcoin was determined by ensuring that the git commit message had a SHA1 signature that was lexigraphically smaller than the difficulty. So add a nonce to your commit message and keep cycling though random numbers until the commit message had a valid signature.
Stripe provided a very slow bash reference implementation, which I still used to pass the level. Instead of increasing the nonce in bash though, I wrote a python script to find a correct hash for me faster.
```import sys
from hashlib import sha1
import random
import string
import Queue as queue
def work(diff, tree, parent, timestamp, q):
diffl = len(diff)
diff = ''.join('0' for x in range(diffl))
body = "tree %snparent %snauthor CTF user <[email protected]> %s +0000ncommitter CTF user <[email protected]> %s +0000nnGive me a Gitcoinnnnonce: " % (tree, parent, timestamp, timestamp)
while True:
body_b = '%s%s' % (body, ''.join(random.choice(string.hexdigits) for x in range(8)))
s = sha1('commit ' + str(len(body_b)) + '' + body_b)
hex = s.hexdigest()[:diffl]
if hex.startswith(diff):
body = body_b
break
q.put(body)
def main():
diff, tree, parent, timestamp = sys.argv[1:]
q = queue.Queue()
th.daemon = True
th.start()
body = bytes(q.get())
with open('/home/carl/level1/test.txt', 'w') as f:
f.write(body)
th.join(0)
if __name__ == '__main__':
main()```
There were some hurdles I came across while solving this, which show in the code. The git hashing command `git hash-object -t commit` didn’t just take the SHA1 hash of its input, it would first prepend `commit len(data)` before hashing. This was easy enough to find with a bit of searching, but a major issue I was having that I couldn’t replicate the SHA1 hash unless I first wrote the commit to a file, rather than streaming via stdout. So I just wrote to a file and modified the miner bash script to change:
```@@ -56,12 +56,12 @@ \$counter"
# See http://git-scm.com/book/en/Git-Internals-Git-Objects for
# details on Git objects.
- sha1=\$(git hash-object -t commit --stdin <<< "\$body")
+ sha1=\$(git hash-object -t commit /home/carl/level1/test.txt)
if [ "\$sha1" "<" "\$difficulty" ]; then
echo
echo "Mined a Gitcoin with commit: \$sha1"
- git hash-object -t commit --stdin -w <<< "\$body" > /dev/null
+ git hash-object -t commit --stdin -w /home/carl/level1/test.txt > /dev/null
git reset --hard "\$sha1" > /dev/null
break
fi```
Which let me get the correct hashes and mine the coin.
## Level 2
Level 2 was all about DDOS attacks. The idea was that there were a number of back end servers, a reverse proxy (which you modified), and a number of clients, some malicious and others not. You had to modify the reverse proxy (called shield) to not let malicious traffic through, and to attempt to minimise back end idleness. Scores were determined by a test harness and also on the git push hook.
Stripe provided the attack code for reference, which made the level really easy. Malicious attackers basically spawned more connections more often, and the numbers that they spawned was defined in the file, as:
```simulationParameters = {
'roundLength': 500, // In ms
'roundCount': 40,
'clientsPerRound': 5,
'pElephant': 0.4,
'mouseRequestsPerRound': 2,
'elephantRequestsPerRound': 50,
'backendCount': 2,
'backendInFlight': 2,
'backendProcessingTime': 75
};```
So from this you can see that malicious clients send 50 requests per round, and normal clients send 2. So my first solution was just to limit the number of connections from each client with a simple counter. My implementation looks like:
```diff --git a/shield b/shield
index c67bd68..8ba87f2 100755
--- a/shield
+++ b/shield
@@ -7,6 +7,7 @@ var httpProxy = require('./network_simulation/lib/proxy');
var checkServer = require('./network_simulation/lib/check_server');
var nopt = require('nopt');
var url = require('url');
+var rcount = {};
var RequestData = function (request, response, buffer) {
this.request = request;
@@ -14,6 +15,16 @@ var RequestData = function (request, response, buffer) {
this.buffer = buffer;
};
+
+function checkRequest(ip){
+ if (rcount[ip] === undefined) {
+ rcount[ip] = 1;
+ } else {
+ rcount[ip]++;
+ }
+ return rcount[ip] <= 4;
+}
+
function ipFromRequest(reqData) {
}
@@ -29,10 +40,10 @@ var Queue = function (proxies, parameters) {
};
Queue.prototype.takeRequest = function (reqData) {
// Reject traffic as necessary:
- // if (currently_blacklisted(ipFromRequest(reqData))) {
- // rejectRequest(reqData);
- // return;
- // }
+ if (!checkRequest(ipFromRequest(reqData))) {
+ rejectRequest(reqData);
+ return;
+ }
// Otherwise proxy it through:
this.proxies[0].proxyRequest(reqData.request, reqData.response, reqData.buffer);
};```
I committed and pushed, and surprisingly, this gave me a passing score!
## Level 3
This is where the story gets sad. I checked out the code, and I could not get the ./test/harness to work correctly. The tak was a file indexing service, and it had to be optimised. It was written in Scala, which I have never used – so I could not work out how to debug it. Stripe released a fix, but it still did not fix my issues. At which point I had to move on to other things and could not complete the CTF.
## A Fractal Height Map Generator in Ruby
[I’m migrating my old articles to the blog in order to switch to it entirely]
Date: 25th March 2010
## Introduction
This article describes the theory behind, and how to implement, a basic fractal height map generator. It is based upon the algorithm defined at http://gameprogrammer.com/fractal.html. Height maps are used in many things: positioning software, graphical rendering, and procedural map generation. Given the right conditions, height maps can be used to create visually stunning images, and are frequently used with an alpha channel to simulate clouds.
All source code used in this article shall be made freely available, under a Creative Commons GPL Licence
The implementation which will be defined here outputs an array of numbers, which on the surface seems fairly mundane. However, with a bit of tweaking with VT100 colour codes, or passing to an image generation program, the algorithm can produce outputs such as this:
The ASCII renderer assigns a colour code to a range of numbers and then depending on your ranges, you can create rainbow-like maps like the one above. The grey scale and transparent images had their number arrays passed to an image generation program called RMagick.
## The Theory
I will go through the basic idea again as it was defined in the gameprogrammer link, to keep a consistency with terms used further in the article. So before we get on to the DiamondSquare algorithm, I shall implement the simpler 1 dimensional algorithm, which will describe the height of a line, similar to a horizon. The patterns created show some fractal behaviour, in that it is said to be self-similar. An object is said to be self-similar when magnified subsets of the object look like, or are identical to, the whole and to each other[1].
In context of this algorithm, it means that as we add more detail, the more rougher and major features will still hold true, but more detail will become apparent as we look closer. This makes the algorithm ideal for recursion or iterative methods. This implementation uses an iterative method.
### Midpoint Displacement in One Dimension
For the creation of the 1 dimensional height map, similar to a horizon, a very simple algorithm is used:
``` def generateLine(length)
# Due to this algorithm being simple for
# the articles sake, length should be
# constrained to the powers of 2.
#
# As we need a midpoint, however, length
# should be defined as (2^n)+1.
# Create an array which describes a line.
# Set the default values to 0American Standard Code for Information Interchange
line = Array.new(length, 0)
# Define the range of the terrain values.
# For this example we shall take the range
# of values to be -63 to 63, with the midpoint
# at 0, out default value.
# Range is then 128.
range = 128;
# Work out the number of line segments
# levels there are in the line. As each line
# segment level is defined by deviding by two
# until length is 1, the number of segments
# is the log_2 of the length.
noSegments = Math.log(length-1, 2)
#Iterate through the levels
(1 .. noSegments).each{ |level|
# Work out the line segment length so you
# can properly address the offset.
segLength = (length/2**level)
# Work out the number of line segments
# within this level
noSegL = (2**level)-1
# Iterate through the line segments and
(1 .. noSegL).each{ |segOffset|
# If value is not zero, skip over it, done on a previous
# level
if( line[segLength*segOffset] == 0 )
# Make sure the current value of the line
# is directly midway between its two parents.
line[segLength*segOffset] = (line[segLength*(segOffset-1)] + line[segLength*(segOffset+1)])/2
# Apply random function to value
line[segLength*segOffset] = randomFunction(line[segLength*segOffset], level, range)
end
}
}
return line
end```
Now as you can see the most important part of that algorithm is that which I have purposely missed, randomFunction. This is where you, quite obviously, define how you want your heights defined. A good way is to simply use a bounded random function, where the bounds are defined by the line segment level you are currently within. For example, a function like: ` `
``` def randomFunction(value, level, range)
# Roughness constant 0 < h < 1
# As h approachs 0, the level dependent
# bounds grow and tend to 1 for all values
# of level
h = 0.8
# Define bounds in terms of level and a roughness
# function
multiplier = 2 ** (-h * level-1)
# Perform random function, bound it, and then apply
# multiplier
value += (rand() * (range) - (range / 2)) * multiplier
# Return
return value
end```
` ` Would offset the value of the line a random amount which is bounded by a function dependent on the line segment level and a roughness coefficient. As this function is the heart of this algorithm and the 2 dimensional algorithm, I will go into some detail on the use of the roughness coefficient. If the roughness coefficient is set to 1, then the multiplier acts the same as : $2^{(-l-1)}; 0 < l < infty ; l in mathbb{Z}^+[/latex]. Decreasing the value of h flattens out the function meaning the bounds are less constrictive and allowing for much rougher terrain. Here is a plot of the multiplier when h=0.8 and h=0.2, and a plot of the generated lines when those constraints are used. X axis is equal to line segment level. [gallery columns="2" ids="434,433"] As you can see, the roughness coefficient makes a massive difference to the outputted numbers. For those interested in recreating the plot, I piped the output of the above code into a text file, and then used GNUPlot to make the images.
### Extending into 2 dimensions - The diamond square algorithm
To extend this algorithm into the second dimension, we have to imagine the terrain data as a two dimensional array of numbers. Each number represents a height in this two dimensional field, and so each column and row can be treated similarly to above.
To split up a two dimensional array in a self-similar way we must use squares, or diamonds, which are analogous to the line segments of the 1 dimensional algorithm. Then, rather than using the ends of a line segment to work out a base height the corners of the square, or diamond, are used. For example:
[gallery columns="2" ids="436,435"]
Like the line segment algorithm, the mathematical 'meat' is the same random function as before. The complexity comes in managing which indexes are part of a diamond or a square. So, for example, here is a code segment which works out indexes of a square, depending on level and location, and applies the random function:
` # Get the corners of an arbitrary square and perform operation # on center. # # @param array Array to use # @param topleftIndexX X index of top left of square # @param topleftIndexY Y index of top left of square # @param length Length of the square # @param level Level into the calculation def processSquare(array, topleftIndexX, topleftIndexY, length, level, range, h) # Get coordinates of the corners of the square toprightIndexX = topleftIndexX toprightIndexY = topleftIndexY + length + ((level == 0) ? -1 : 0) bottomleftIndexX = topleftIndexX + length + ((level == 0) ? -1 : 0) bottomleftIndexY = topleftIndexY bottomrightIndexX = topleftIndexX + length + ((level == 0) ? -1 : 0) bottomrightIndexY = topleftIndexY + length + ((level == 0) ? -1 : 0) middleX = topleftIndexX + (length)/2 middleY = topleftIndexY + (length)/2 # Get values topleftValue = array[topleftIndexX][topleftIndexY] toprightValue = array[toprightIndexX][toprightIndexY] bottomleftValue = array[bottomleftIndexX][bottomleftIndexY] bottomrightValue = array[bottomrightIndexX][bottomrightIndexY] # Get average average = (topleftValue + toprightValue + bottomleftValue + bottomrightValue)/4 # Set new value array[middleX][middleY] = average + calculateOffset(level, range, h) end`
Where calculateOffset is the random function in this application. The diamond calculation algorithm is very similar and looks like this:
` # Get the edges of an arbitrary diamond and perform operation # on center # # @param array Array to use # @param topIndexX X index of top of diamond # @param topIndexY Y index of top of diamond # @param length Length of diamond # @param level Level into the calculation def processDiamond(array, topIndexX, topIndexY, arraylength, level, range, h) # Adjust arraylength -= 1 length = arraylength/(2 ** level) #Get coordinates of the diamond rightIndexX = topIndexX + length/2 rightIndexY = (topIndexY == length) ? length/2 : topIndexY + length/2 leftIndexX = topIndexX + length/2 leftIndexY = (topIndexY == 0) ? arraylength - length/2 : topIndexY - length/2 bottomIndexX = (topIndexX + length/2 == arraylength) ? length/2 : topIndexX + length bottomIndexY = topIndexY middleX = topIndexX + length/2 middleY = topIndexY # Get values topValue = array[topIndexX][topIndexY] rightValue = array[rightIndexX][rightIndexY] bottomValue = array[bottomIndexX][bottomIndexY] leftValue = array[leftIndexX][leftIndexY] # Get average average = (topValue + rightValue + bottomValue + leftValue)/4 # Set new value array[middleX][middleY] = average + calculateOffset(level, range, h) # Wraps if(middleX == arraylength) array[0][middleY] = array[middleX][middleY] end if(middleY == 0) array[middleX][arraylength] = array[middleX][middleY] end end`
The only difference with the above snippet is the different indices it retrieves, and that it must handle wrap around for some of the edges.
So currently, we can create arbitrary diamonds and squares within a 2-dimensional array and assign a fuzzy average of the edges according the h value. Now all we need is some code to manage traversing through the levels of iterations and through the diamonds and squares themselves. Here is my solution:
` # The main control loop for the algorithm. # # @param lengthExp Length exponent # @param range Value range # @param h Roughness constant def generateTerrain(lengthExp, range, h) length = (2 ** lengthExp) + 1 array = Array.new array = createArray(array, length) #Go through Levels (irerative recursion) (0 .. lengthExp - 1).each{ |level| # Iterator for the Square part of the algorithm # Will go through the x-axis coords (0 .. (2 ** level) -1 ).each { |sqx| # Y axis coords (0 .. (2 ** level) -1).each { |sqy| gap = length/2 ** level x = (0 + (gap*sqx)) y = (0 + (gap*sqy)) processSquare(array, x, y, gap, level, range, h) } } # Iterator for the diamond part of the algorithm (0 ... (2 ** (level+1))).each { |dix| # Offset in the number of points on the y-axis. Dependant # on if x iteration is even or odd. offset = (dix.even?) ? 1 : 2 (0 ... (2 ** (level+1)/2)).each { |diy| gap = (length/2 ** (level+1)) ygap = 2 * gap x = (0 + (gap*dix)) if (dix.even?) y = 0 + (ygap*diy) else y = gap + (ygap*diy) end processDiamond(array, x, y, length, level, range, h) } } } return array end`
And this gives us our array with its height map hidden inside. Using a library like RMagick we can output images like the ones shown above. To create the gray scale image, the following code was used:
` image = Image.new(array.length, array.length) (0 ... array.length).each { |x| (0 ... array[x].length).each { |y| val = array[x][y] * (2**9) # Create greyscale image image.pixel_color(x, y, Pixel.new(val, val, val, val)) } } image.display`
Which just takes the value in the array, and multiplies it by 512 which gives the values a range of [latex]0 ge v ge 2^{15}, ; frac{v}{512} in mathbb{Z}$
. This gives us the gaseous image that has been generated above.
## Code Listings
A library version of the ruby code found in this tutorial can be found at GitHub.
## References
1. Voss, Richard D., FRACTALS in NATURE: characterization, measurement, and simulation. SIGGRAPH 1987
Based on a work at gameprogrammer.com.
## Ruby gem – json_serialisable
I was working on a ruby project and stumbed upon my first valid application of metaprogramming. I was creating json serialisation methods and realised they were all practically identical. So I looked at how `attr_accessor` worked and then wrote my own class method called `attr_serialisable`. This method generated serialisation methods automatically.
## Example
Given a class `A`
```class A
attr_accessor :a, :b, :c
attr_serialisable :a, :b, :c
def initialize(a, b, c)
@a, @b, @c = a, b, c
end
end```
`attr_serialisable` would generate the following methods:
``` def to_json(*a)
{
"json_class" => self.class.name,
"a" => @a,
"b" => @b,
"c" => @c
}.to_json(*a)
end
def json_create(o)
new(*o["a"], *o["b"], *o["c"])
end```
Which will allow the class to easily be used by the ‘json’ library.
## Programming languages course
So I ran a talk on learning programming languages last week. It was the second time I had done that particular talk, and in this case the hardware setup went smoothly – as it was done by Stephen Wattam the CSLU VP.
We had a pretty good turn out, mostly of year year undergraduate students who so far had only played with a little C. I took pictures of everyone hard at work doing their task … well, ok. They were mostly on tryruby.org which was even better.
It showed that they had an interest in a new language which is fairly good at prototyping and will allow them to try out their ideas fast. I may have semi pushed them on to it in my talk, so I’m glad they were listening. No one tried learning Haskell though, but then I’ll drop in on everyone next term and see how they are doing. The slides and some info for my talk can be found at the CSLU site.
On a side note … My Instagram tshirt came! I’m not sure if I’ll ever wear it outside as it’s a bit long, but still!
## Rain – Agent-based water
Well I’ve been wanting to do this for a while now, and on Sunday with a freshly installed (and therefore speedy) net book under my belt, I thought I’d have a crack at it.
Last year (maybe even 2 years now) ago, I made a weak plasmoid generator with the intention of using it for terrain generation. I’ve always wanted to use that library for some agent based programming, and a simple (rule wise) example of it would be water. You put some water agents on the map they move as low as they can go, then evaporate. This kind of does that, and definitely suffers from “proof of concept” syndrome. Water moves, but to do anything fancy will require redoing, which I’ll probably end up doing on my next free Sunday.
So, using a library called Gosu to handle the drawing and the event loop, and a library called TexPlay which allowed me to modify pixels, I got a render up and running which displayed a map of tiles (1 pixel tile 😉 ), and the colour was defined with a lambda that was passed to all of them.
As I’m learning Haskell at the moment, I thought I’d give some lambdas a go, and it made it really easy actually.
There are two types of agents in this program, Rain and Sources.
• Rain just flows to a low point.
• Sources make Rains.
Rains become sources if they hit a low point, which basically has the effect of stacking the Rains that have pooled there so they can make lakes. As Rains are destroyed when they stop, and Sources can only produce a finite amount of Rains based on how many are there when it is made, the system sort of stays constant. Initial sources are given enough Rains to cover the whole map 1 deep.
That is awkward to explain.
Most of the issues with this program was making the renderer fast enough to work on a net book, and as I’m not a graphics man, I made many rooky mistakes.
This is fairly mesmirizing to watch, and I’ll definitely improve it further, by:
• Making the map colouring sample from colour->height table
• Have water level as a tile attribute to make things cleaner
• Fix evaporation
• Make it so that tiles which have a constant flow of agents over them are distinguished from one-off “rain” paths
• Fix Rain
It’s a project, feel free to fork from git hub here at https://github.com/carl-ellis/Rain
Old school screen capture.
Video here: Rain – agent-based
## Rails 3 and lighttpd
This was performed on Archlinux with lighttpd 1.4.28 and rails 3.0.3
## Prerequisites
Required packages:
• lighttpd,
• fcgi,
• ruby,
• and their dependencies…
## Ruby Setup
Required gems:
• fcgi,
• bundler
(if you are behind a proxy, the magic gem command is :
``# gem install GEM -r -p "http://[PROXY_URL]:[PROXY_PORT]"``
)
Once you have that you need to create a “dispatch.fcgi” script to do all the rails magic. I found an example one at http://stackoverflow.com/questions/3296206/rails-3-and-fcgi .
``````#!/usr/bin/ruby
require 'rubygems'require 'fcgi'
require_relative '../config/environment'
class Rack::PathInfoRewriter
def initialize(app)
@app = app
end
def call(env)
env.delete('SCRIPT_NAME')
parts = env['REQUEST_URI'].split('?')
env['PATH_INFO'] = parts[0]
env['QUERY_STRING'] = parts[1].to_s
@app.call(env)
end
end
Rack::Handler::FastCGI.run Rack::PathInfoRewriter.new(YOUR_APP_NAME::Application)
``````
Running a “bundle install” from your app root will make sure all the necessary gems are available for local use. Follow these instructions and run “ruby public/dispatch.fcgi”, if you get no errors, voila!
## Lighttpd Setup
Now, to set up lighttpd you need to merge this with your config:
``````server.modules += ( "mod_fastcgi", "mod_rewrite" )
\$HTTP["host"] == "localhost" {
server.document-root = "/path/to/your/app/public/"
server.dir-listing = "disable"
server.error-handler-404 = "/dispatch.fcgi"
fastcgi.server = (
".fcgi" => (
"localhost" => (
"min-procs" => 1,
"max-procs" => 1,
"socket" => "/tmp/ruby-beholder.socket",
"bin-path" => "/path/to/your/app/public/dispatch.fcgi",
"bin-environment" => ( "RAILS_ENV" => "development" )
)
)
)
}``````
A quick “sudo /etc/rc.d/lighttpd restart” and a check of the error logs will tell you if it has worked
## Battery Monitor – rbatmon
I use a rather spartan windowing manager called awesome in all of my machines. This has been a fine setup until I used it on my netbook due to one small issue, battery monitors.
On my desktop machines and the laptop I use gkrellm to monitor cpu and memory and for the laptop it has a handy battery usage label. With the netbook however, screen real estate is quite valuable, so I opted for finding something to sit in the system tray.
After a quick look it seems there was nothing which was lightweight or simple or not requiring me to install the entirety of gnome.
In the end I made my own called rbatmon, then packaged it up for use in the AUR. If you have a substandard flavour of linux, not to worry, You can grab the script from my githib page here.
The most interesting challenge of this was building a package for the first time. There is a great package for Archlinux called abs (available on pacman) which fills /usr/share/pacman with some example PKGBUILDS for standard sources of gettings code from VCS’s.
Page on my site regarding this is here.
AUR page is here.
C
## Ruby and Watir: Sending keyboard events to an element
Ok, so you need to send certain keyboard events to an element to properly test a webpage, but stuck how to do it?
Ive looked at some tutorials on the web, but there doesn’t seem a simple solution.
However, I have been experimenting, and this method seems to work fine.
``````# First off create your Watir::IE object
ie = Watir::IE.new
# Then navigate to the page you are testing
ie.goto("mypage.myserver.com")
# Grab the descriptor of the element you wish to send a keyboard command to
# (for example, a text field)
element = ie.textField(:id, "myText")
# Now, I found that keyboard events only work if the Watir::IE window is on top and has
# focus, so for example if we wish to send a "Pageup" keyboard command to the element
# "myText" we would do so by
ie.bring_to_front
element.focus
element.container.focus
element.container.send_keys("{PGUP"})
``````
` `
`This method does require Autoit(http://www.autoitscript.com/autoit3/) to be installed, and a full list of keyboard events can be found here: http://www.autoitscript.com/autoit3/docs/appendix/SendKeys.htm`
` `
|
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|
https://math.stackexchange.com/questions/3345073/two-very-advanced-harmonic-series-of-weight-5
|
# Two very advanced harmonic series of weight $5$
Very recently Cornel discovered two (update: in fact there are more as seen from the new entires) fascinating results involving harmonic series using ideas from his book, (Almost) Impossible Integrals, Sums, and Series, and which are the core of a new paper he's preparing:
$$\begin{equation*} \sum _{n=1}^{\infty } \frac{H_n H_{2 n}}{(2 n)^3} \end{equation*}$$ $$\begin{equation*} =\frac{307}{128}\zeta(5)-\frac{1}{16}\zeta (2) \zeta (3)+\frac{1}{3}\log ^3(2)\zeta (2) -\frac{7}{8} \log ^2(2)\zeta (3)-\frac{1}{15} \log ^5(2) \end{equation*}$$ $$\begin{equation*} -2 \log (2) \operatorname{Li}_4\left(\frac{1}{2}\right) -2 \operatorname{Li}_5\left(\frac{1}{2}\right); \end{equation*}$$ and $$\begin{equation*} \sum _{n=1}^{\infty } \frac{H_n H_{2 n}}{(2 n-1)^3} \end{equation*}$$ $$\begin{equation*} =6 \log (2)-2 \log ^2(2)-\frac{1}{12}\log ^4(2)+\frac{1}{12} \log ^5(2)-\frac{3}{2} \zeta (2)-\frac{21}{8} \zeta (3)+\frac{173}{32} \zeta (4) \end{equation*}$$ $$\begin{equation*} +\frac{527}{128} \zeta (5)-\frac{21 }{16}\zeta (2) \zeta (3)+\frac{3}{2} \log (2) \zeta (2)-\frac{7}{2}\log (2)\zeta (3)-4\log (2)\zeta (4)+\frac{1}{2} \log ^2(2) \zeta (2) \end{equation*}$$ $$\begin{equation*} -\frac{1}{2} \log ^3(2)\zeta (2)+\frac{7}{4}\log ^2(2)\zeta (3)-2 \operatorname{Li}_4\left(\frac{1}{2}\right)+2 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right), \end{equation*}$$ or, after adjustments, the form $$\sum _{n=1}^{\infty}\frac{H_n H_{2 n}}{(2 n+1)^3}$$ $$=\frac{1}{12}\log ^5(2)+\frac{31}{128} \zeta (5)-\frac{1}{2} \log ^3(2)\zeta (2)+\frac{7}{4} \log ^2(2) \zeta (3)-\frac{17}{8} \log (2)\zeta (4) \\+2\log (2) \operatorname{Li}_4\left(\frac{1}{2}\right).$$ Update I : A new series entry obtained based on the aforementioned series $$\begin{equation*} \sum _{n=1}^{\infty } \frac{H_n H_{2 n}^{(2)}}{(2 n)^2} \end{equation*}$$ $$\begin{equation*} =\frac{23 }{32}\zeta (2) \zeta (3)-\frac{581}{128} \zeta (5)-\frac{2}{3}\log ^3(2) \zeta (2)+\frac{7}{4} \log^2(2)\zeta (3) +\frac{2}{15} \log ^5(2) \end{equation*}$$ $$\begin{equation*} +4\log (2) \operatorname{Li}_4\left(\frac{1}{2}\right) +4 \operatorname{Li}_5\left(\frac{1}{2}\right); \end{equation*}$$ Update II : Another new series entry obtained based on the aforementioned series $$\begin{equation*} \sum _{n=1}^{\infty } \frac{H_n H_{2 n}^2}{(2 n)^2} \end{equation*}$$ $$\begin{equation*} =\frac{23 }{32}\zeta (2) \zeta (3)+\frac{917 }{128}\zeta (5)+\frac{2}{3} \log ^3(2)\zeta (2)-\frac{7}{4} \log ^2(2)\zeta (3)-\frac{2}{15} \log ^5(2) \end{equation*}$$ $$\begin{equation*} -4 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right)-4 \operatorname{Li}_5\left(\frac{1}{2}\right); \end{equation*}$$ Update III : And a new series entry from the same class of series with an unexpected (and outstanding) closed-form $$\begin{equation*} \sum _{n=1}^{\infty } \frac{H_{2n} H_{n}^{(2)}}{(2 n)^2}=\frac{101 }{64}\zeta (5)-\frac{5 }{16}\zeta (2) \zeta (3); \end{equation*}$$ It's interesting to note that $$\displaystyle \sum _{n=1}^{\infty } \frac{H_{n} H_{n}^{(2)}}{n^2}=\zeta(2)\zeta(3)+\zeta(5)$$, which may be found calculated in the book, (Almost) Impossible Integrals, Sums, and Series, by series manipulations.
A note: The series from UPDATE III seems to be known in literature, and it already appeared here https://math.stackexchange.com/q/1868355 (see $$(3)$$).
Update IV : Again a new series entry from the same class of series $$\begin{equation*} \sum _{n=1}^{\infty } \frac{H_n^2 H_{2 n}}{(2 n)^2} \end{equation*}$$ $$\begin{equation*} =\frac{9 }{16}\zeta (2) \zeta (3)+\frac{421 }{64}\zeta (5)+\frac{2}{3} \log ^3(2)\zeta (2) -\frac{7}{4} \log ^2(2)\zeta (3) -\frac{2}{15} \log^5(2) \end{equation*}$$ $$\begin{equation*} -4 \log(2)\operatorname{Li}_4\left(\frac{1}{2}\right) -4 \operatorname{Li}_5\left(\frac{1}{2}\right); \end{equation*}$$ Update V : A strong series - September 26, 2019 $$\sum _{n=1}^{\infty } \frac{H_{2n} H_n^{(2)}}{(2 n+1)^2}$$ $$=\frac{4}{3}\log ^3(2)\zeta (2) -\frac{7}{2}\log^2(2)\zeta (3)-\frac{21}{16}\zeta(2)\zeta(3)+\frac{713}{64} \zeta (5)-\frac{4}{15} \log ^5(2)$$ $$-8 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right) -8\operatorname{Li}_5\left(\frac{1}{2}\right);$$ Update VI : Three very challenging series - September 28, 2019 $$i) \ \sum _{n=1}^{\infty } \frac{H_n H_{2 n}^{(2)}}{(2 n+1)^2}$$ $$=\frac{35}{32} \zeta (2) \zeta (3)-\frac{651}{128} \zeta (5)+\frac{1}{3}\log^3(2)\zeta(2)-\frac{7}{4}\log^2(2)\zeta (3)+\frac{53}{16} \log (2)\zeta (4) -\frac{1}{30} \log ^5(2)$$ $$+4 \operatorname{Li}_5\left(\frac{1}{2}\right);$$ $$ii) \ \sum _{n=1}^{\infty } \frac{H_n H_{2 n}^2}{(2 n+1)^2}$$ $$=\frac{35}{32} \zeta (2) \zeta (3)+\frac{465}{128} \zeta (5)+\frac{1}{2}\log^3(2)\zeta(2)-\frac{7}{4}\log^2(2)\zeta (3)-\frac{11}{16} \log (2)\zeta (4) -\frac{1}{12} \log ^5(2)$$ $$-2\log(2) \operatorname{Li}_4\left(\frac{1}{2}\right);$$ $$iii) \ \sum _{n=1}^{\infty } \frac{H_n^2 H_{2 n}}{(2 n+1)^2}$$ $$=\frac{21}{16} \zeta (2) \zeta (3)-\frac{217}{64} \zeta (5)+\frac{2}{3}\log^3(2)\zeta(2)-\frac{7}{4}\log^2(2)\zeta (3)+ \log (2)\zeta (4) -\frac{1}{15} \log ^5(2)$$ $$+8\operatorname{Li}_5\left(\frac{1}{2}\right);$$ Update VII : Critical series relation used in the Update VI - September 28, 2019 $$i) \sum _{n=1}^{\infty } \frac{H_n H_{2 n}^2}{(2 n+1)^2}-\sum _{n=1}^{\infty } \frac{H_n H_{2 n}^{(2)}}{(2 n+1)^2}$$ $$=\frac{1}{6}\log ^3(2)\zeta (2) -4\log (2)\zeta (4)+\frac{279}{32} \zeta (5)-\frac{1}{20} \log ^5(2)-2 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right) -4 \operatorname{Li}_5\left(\frac{1}{2}\right);$$ $$ii) \ 4 \sum _{n=1}^{\infty } \frac{H_n H_{2 n}^2}{(2 n+1)^2}-\sum _{n=1}^{\infty } \frac{H_n^2 H_{2 n}}{(2 n+1)^2}$$ $$=\frac{49}{16} \zeta (2) \zeta (3)+\frac{1147}{64}\zeta (5)+\frac{4}{3}\log^3(2)\zeta (2) -\frac{21}{4} \log ^2(2)\zeta (3) -\frac{15}{4}\log (2)\zeta (4)-\frac{4}{15} \log ^5(2)$$ $$-8 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right) -8\operatorname{Li}_5\left(\frac{1}{2}\right),$$ where $$H_n^{(m)}=1+\frac{1}{2^m}+\cdots+\frac{1}{n^m}, \ m\ge1,$$ designates the $$n$$th generalized harmonic number of order $$m$$, $$\zeta$$ represents the Riemann zeta function, and $$\operatorname{Li}_n$$ denotes the Polylogarithm function.
A note: for example, for those interested, one of the possible ways of calculating both series from UPDATE III and UPDATE IV is based on building a system of relations with the two series by exploiting $$\displaystyle \int_0^1 x^{n-1} \log^2(1-x)\textrm{d}x=\frac{H_n^2+H_n^{(2)}}{n}$$ and $$\displaystyle \sum_{n=1}^{\infty} x^n(H_n^2-H_n^{(2)})=\frac{\log^2(1-x)}{1-x}$$. Apart from this, the series from UPDATE III allows at least a (very) elegant approach by using different means.
Using the first series we may obtain (based on the series representation of $$\log(1-x)\log(1+x)$$ and the integral $$\int_0^1 x^{n-1}\operatorname{Li}_2(x)\textrm{d}x$$) a way for proving that $$\int_0^1 \frac{\operatorname{Li}_2(x) \log (1+x) \log (1-x)}{x} \textrm{d}x=\frac{29 }{64}\zeta (5)-\frac{5 }{8}\zeta (2) \zeta (3).$$
Then, based on the solution below and using the alternating harmonic series in the book, (Almost) Impossible Integrals, Sums, and Series, we have
$$\int_0^1 \frac{\operatorname{Li}_2(-x) \log (1+x) \log (1-x)}{x} \textrm{d}x$$ $$=\frac{5 }{16}\zeta (2) \zeta (3)+\frac{123 }{32}\zeta (5)+\frac{2}{3} \log ^3(2)\zeta (2)-\frac{7}{4} \log ^2(2)\zeta (3)-\frac{2}{15}\log ^5(2)\\-4 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right)-4 \operatorname{Li}_5\left(\frac{1}{2}\right).$$ And if we add up the two previous integrals, we get $$\int_0^1 \frac{\operatorname{Li}_2(x^2) \log (1+x) \log (1-x)}{x} \textrm{d}x$$ $$=\frac{275}{32}\zeta (5)-\frac{5 }{8}\zeta (2) \zeta (3)+\frac{4}{3} \log ^3(2)\zeta (2)-\frac{7}{2} \log ^2(2)\zeta (3)-\frac{4}{15}\log ^5(2)\\-8 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right)-8 \operatorname{Li}_5\left(\frac{1}{2}\right).$$ Update (integrals): Another curious integral arising during the calculations $$\int_0^1 \frac{x \log (x) \log(1-x^2) \operatorname{Li}_2(x)}{1-x^2} \textrm{d}x=\frac{41 }{32}\zeta (2) \zeta (3)-\frac{269 }{128}\zeta (5).$$
QUESTION: Have these series ever been known in literature? I'm not interested in solutions but only if the series appear anywhere in the literature.
• David Bailey would be as likely to know as anyone. – Gerry Myerson Sep 5 at 12:29
• Cornel is the real boss. – Ali Shather Sep 5 at 17:09
• Have you tried to contact Bailey, 97357329? – Gerry Myerson Sep 6 at 13:09
• @GerryMyerson May I guess you refer to David H. Bailey? en.wikipedia.org/wiki/David_H._Bailey_(mathematician). I didn't yet. I don't know him personally. – user97357329 Sep 6 at 13:13
• Yes, that's the man. He's very approachable & I think he'd be interested. – Gerry Myerson Sep 6 at 22:50
A solution in large steps by Cornel Ioan Valean:
Considering $$\displaystyle -\log(1+y)\log(1-y)=\sum_{n=1}^{\infty} y^{2n} \frac{H_{2n}-H_n}{n}+\frac{1}{2}\sum_{n=1}^{\infty} \frac{y^{2n}}{n^2}$$ where we divide both sides by $$y$$ and then integrate from $$y=0$$ to $$y=x$$, we have $$\displaystyle -\int_0^x \frac{\log(1+y)\log(1-y)}{y}\textrm{d}y=\sum_{n=1}^{\infty} x^{2n} \frac{H_{2n}-H_n}{2n^2}+\frac{1}{4}\sum_{n=1}^{\infty} \frac{x^{2n}}{n^3}$$. Now, if we multiply both sides of this last result by $$\log(1+x)/x$$ and then integrate from $$x=0$$ to $$x=1$$, using the fact that $$\displaystyle \int_0^1 x^{2n-1}\log(1+x) \textrm{d}x=\frac{H_{2n}-H_n}{2n}$$, we get
{A specific note: one can multiply both sides of the relation above by $$\log(1-x)/x$$ instead of $$\log(1+x)/x$$ and use the integral, $$\int_0^1 x^{n-1}\log(1-x)\textrm{d}x=-H_n/n$$, but later in the process one might like to use though the version $$\int_0^1 x^{2n-1}\log(1+x) \textrm{d}x$$ to nicely get the calculations.}
$$\underbrace{-\int_0^1 \frac{\log(1+x)}{x}\left(\int_0^x \frac{\log(1+y)\log(1-y)}{y}\textrm{d}y\right)\textrm{d}x}_{\displaystyle I}=\frac{5}{4}\sum_{n=1}^{\infty}\frac{H_n^2}{n^3}+\frac{7}{8}\sum_{n=1}^{\infty}\frac{H_n}{n^4}-\sum_{n=1}^{\infty}(-1)^{n-1}\frac{H_{n}}{n^4}-\displaystyle\sum_{n=1}^{\infty}(-1)^{n-1}\frac{H_n^2}{n^3}-\frac{1}{2}\sum_{n=1}^{\infty}\frac{H_nH_{2n}}{n^3}.$$
Integrating by parts, the integral $$I$$ may be written as $$5/16\zeta(2)\zeta(3)-\underbrace{\int_0^1 \frac{\text{Li}_2(-x) \log (1+x) \log (1-x)}{x} \textrm{d}x}_{J}$$, and then we may write that $$\sum_{n=1}^{\infty}\frac{H_nH_{2n}}{n^3}=2\int_0^1 \frac{\text{Li}_2(-x) \log (1+x) \log (1-x)}{x} \textrm{d}x-\frac{5}{8}\zeta(2)\zeta(3)+\frac{5}{2}\sum_{n=1}^{\infty}\frac{H_n^2}{n^3}+\frac{7}{4}\sum_{n=1}^{\infty}\frac{H_n}{n^4}-2\sum_{n=1}^{\infty}(-1)^{n-1}\frac{H_{n}}{n^4}-2\sum_{n=1}^{\infty}(-1)^{n-1}\frac{H_n^2}{n^3}\tag1 .$$
Now, the last magical part comes from considering expressing the integral $$J$$ in a different way, and by using the Cauchy product, $$\displaystyle \operatorname{Li}_2(-x)\log(1+x)=3\sum_{n=1}^{\infty}(-1)^n \frac{x^n}{n^3}-2 \sum_{n=1}^{\infty}(-1)^n x^n\frac{H_n}{n^2}-\sum_{n=1}^{\infty}(-1)^nx^n\frac{H_n^{(2)}}{n}$$, we get that
$$\int_0^1 \frac{\operatorname{Li}_2(-x) \log (1+x) \log (1-x)}{x} \textrm{d}x= -\sum _{n=1}^{\infty }(-1)^{n-1}\frac{ H_n H_n^{(2)}}{n^2}+3\sum _{n=1}^{\infty }(-1)^{n-1}\frac{ H_n}{n^4}\\-2\sum _{n=1}^{\infty }(-1)^{n-1}\frac{H_n^2}{n^3}.\tag2$$
Combining $$(1)$$ and $$(2)$$ and collecting the values of the series from the book, (Almost) Impossible Integrals, Sums, and Series, we are done with the first series.
To get the value of the second series we might use the relation:
$$\begin{equation*} \sum _{n=1}^{\infty } \frac{H_n H_{2 n}}{(2 n-1)^3}-\sum _{n=1}^{\infty } \frac{H_n H_{2 n}}{(2 n)^3} \end{equation*}$$ $$\begin{equation*} =6 \log (2)-2 \log ^2(2)-\frac{1}{12}\log ^4(2)+\frac{3}{20} \log ^5(2)-\frac{3}{2} \zeta (2)-\frac{21}{8} \zeta (3)+\frac{173}{32} \zeta (4) \end{equation*}$$ $$\begin{equation*} +\frac{55}{32} \zeta (5)-\frac{5 }{4}\zeta (2) \zeta (3)+\frac{3}{2} \log (2) \zeta (2)-\frac{7}{2}\log (2)\zeta (3)-4\log (2)\zeta (4)+\frac{1}{2} \log ^2(2) \zeta (2) \end{equation*}$$ $$\begin{equation*} -\frac{5}{6} \log ^3(2)\zeta (2)+\frac{21}{8}\log ^2(2)\zeta (3)-2 \operatorname{Li}_4\left(\frac{1}{2}\right)+4 \log (2)\operatorname{Li}_4\left(\frac{1}{2}\right)+2 \operatorname{Li}_5\left(\frac{1}{2}\right), \end{equation*}$$
and this is obtained by using a very similar strategy to the one give in Section 6.59, pages $$530$$-$$532$$, from the book, (Almost) Impossible Integrals, Sums, and Series. The critical identity here is given in (6.289).
A detailed solution will appear soon in a new paper.
UPDATE (September $$30$$, $$2019$$)
A magical way to the series $$\sum_{n=1}^\infty\frac{H_{2n}H_n^{(2)}}{(2n)^2}$$ by Cornel Ioan Valean
By the Cauchy product, we have $$\operatorname{Li}_2(x^2) \log(1-x^2)= 3\sum _{n=1}^{\infty } \frac{x^{2 n}}{n^3}-2\sum _{n=1}^{\infty } x^{2n}\frac{H_n}{n^2}-\sum _{n=1}^{\infty } x^{2n}\frac{H_n^{(2)}}{n}$$, and if we multiply both sides by $$\log(1-x)/x$$, and integrate from $$x=0$$ to $$x=1$$, using that $$\int_0^1 x^{n-1}\log(1-x)\textrm{d}x=-H_n/n$$, and doing all the reductions, we arrive at
$$2\sum _{n=1}^{\infty } \frac{H_{2 n} H_n^{(2)}}{(2 n)^2}-12\sum _{n=1}^{\infty } \frac{H_n}{n^4}+12\sum _{n=1}^{\infty }(-1)^{n-1} \frac{H_n}{n^4}+\sum _{n=1}^{\infty } \frac{H_n H_{2 n}}{n^3}$$ $$=\int_0^1 \frac{\text{Li}_2\left(x^2\right) \log \left(1-x^2\right) \log (1-x)}{x} \textrm{d}x$$ $$=\int_0^1 \frac{\text{Li}_2\left(x^2\right) \log (1+x) \log (1-x)}{x} \textrm{d}x+2 \int_0^1 \frac{\text{Li}_2(-x) \log ^2(1-x)}{x} \textrm{d}x\\+2 \int_0^1 \frac{\text{Li}_2(x) \log ^2(1-x)}{x} \textrm{d}x$$ $$=\int_0^1 \frac{\text{Li}_2\left(x^2\right) \log (1+x) \log (1-x)}{x} \textrm{d}x+2 \sum _{n=1}^{\infty } \frac{H_n^2}{n^3}-2 \sum _{n=1}^{\infty } \frac{(-1)^{n-1}H_n^2}{n^3}+2 \sum _{n=1}^{\infty } \frac{H_n^{(2)}}{n^3}\\-2 \sum _{n=1}^{\infty }(-1)^{n-1} \frac{ H_n^{(2)}}{n^3},$$ where the last integral is given here Two very advanced harmonic series of weight $5$, and all the last resulting harmonic series are given in the book (Almost) Impossible Integrals, Sums, and Series. The reduction to the last series has been achieved by using the identity, $$\displaystyle \int_0^1 x^{n-1}\log^2(1-x)\textrm{d}x=\frac{H_n^2+H_n^{(2)}}{n}$$. The series $$\sum _{n=1}^{\infty } \frac{H_n H_{2 n}}{n^3}$$ maybe found calculated in the paper On the calculation of two essential harmonicseries with a weight 5 structure, involving harmonic numbers of the type H_{2n} by Cornel Ioan Valean. Thus, we have
$$\sum_{n=1}^\infty\frac{H_{2n}H_n^{(2)}}{(2n)^2}=\frac{101}{64}\zeta(5)-\frac5{16}\zeta(2)\zeta(3).$$
All the details will appear in a new paper.
UPDATE (October $$30$$, $$2019$$) The details with respect to the evaluation of the previous series may be found in the preprint The evaluation of a special harmonic series with a weight $$5$$ structure, involving harmonic numbers of the type $$H_{2n}$$
• (+1) for sharing such awesome stuff. – Ali Shather Sep 5 at 17:14
• @AliShather Thank you. – user97357329 Sep 6 at 7:54
We have
$$\frac{\ln^2(1-y)}{1-y}=\sum_{n=1}^\infty y^n(H_n^2-H_n^{(2)})\tag{1}$$
integrate both sides of (1) from $$y=0$$ to $$y=x$$ to get
$$-\frac13\ln^3(1-x)=\sum_{n=1}^\infty\frac{x^{n+1}}{n+1}\left(H_n^2-H_n^{(2)}\right)=\sum_{n=1}^\infty\frac{x^{n}}{n}\left(H_n^2-H_n^{(2)}-\frac{2H_n}{n}+\frac{2}{n^2}\right)\tag{2}$$
Now replace $$x$$ with $$x^2$$ in (2) then multiply both sides by $$-\frac{\ln(1-x)}{x}$$ and integrate from $$x=0$$ to $$x=1$$, also note that $$\int_0^1 -x^{2n-1}\ln(1-x)\ dx=\frac{H_{2n}}{2n}$$ we get
$$\frac13\underbrace{\int_0^1\frac{\ln^3(1-x^2)\ln(1-x)}{x}\ dx}_{\large I}=\sum_{n=1}^\infty\frac{H_{2n}}{2n^2}\left(H_n^2-H_n^{(2)}-\frac{2H_n}{n}+\frac{2}{n^2}\right)$$
Rearranging the terms to get
$$\sum_{n=1}^\infty\frac{H_{2n}H_n^2}{(2n)^2}=\sum_{n=1}^\infty\frac{H_{2n}H_n^{(2)}}{(2n)^2}+4\sum_{n=1}^\infty\frac{H_{2n}H_n}{(2n)^3}-8\sum_{n=1}^\infty\frac{H_{2n}}{(2n)^4}+\frac16I\tag{3}$$
@nospoon mentioned in equation (3) of his solution that he found
$$\sum_{n=1}^{\infty} \frac{H_{n-1}^{(2)}\,H_{2n}}{n^2} =\frac{11}{4}\zeta(2)\,\zeta(3)-\frac{47}{16}\zeta(5)$$
Or
$$\boxed{\sum _{n=1}^{\infty } \frac{H_{2n} H_{n}^{(2)}}{(2 n)^2}=\frac{101 }{64}\zeta (5)-\frac{5 }{16}\zeta (2) \zeta (3)}$$
Also Cornel elegantly calculated the second sum above
$$\boxed{\small{\sum _{n=1}^{\infty } \frac{H_{2 n}H_n }{(2 n)^3}=\frac{307}{128}\zeta(5)-\frac{1}{16}\zeta (2) \zeta (3)+\frac{1}{3}\ln ^3(2)\zeta (2) -\frac{7}{8} \ln ^2(2)\zeta (3)-\frac{1}{15} \ln ^5(2) -2 \ln (2) \operatorname{Li}_4\left(\frac{1}{2}\right) -2 \operatorname{Li}_5\left(\frac{1}{2}\right)}}$$
For the third sum: $$\sum_{n=1}^\infty\frac{H_{2n}}{(2n)^4}=\frac12\sum_{n=1}^\infty\frac{H_{n}}{n^4}+\frac12\sum_{n=1}^\infty(-1)^n\frac{H_{n}}{n^4}$$
plugging the common results:
$$\sum_{n=1}^\infty\frac{H_{n}}{n^4}=3\zeta(5)-\zeta(2)\zeta(3)$$
$$\sum_{n=1}^\infty(-1)^n\frac{H_{n}}{n^4}=\frac12\zeta(2)\zeta(3)-\frac{59}{32}\zeta(5)$$
we get
$$\boxed{\sum_{n=1}^\infty\frac{H_{2n}}{(2n)^4}=\frac{37}{64}\zeta(5)-\frac14\zeta(2)\zeta(3)}$$
For the remaining integral $$I$$, we use the magical identity
$$(a+b)^3a=a^4-b^4+\frac12(a+b)^4-\frac12(a-b)^4-(a-b)^3b$$
with $$a=\ln(1-x)$$ and $$b=\ln(1+x)$$ we can write
$$I=\int_0^1\frac{\ln^4(1-x)}{x}\ dx-\int_0^1\frac{\ln^4(1+x)}{x}\ dx+\frac12\underbrace{\int_0^1\frac{\ln^4(1-x^2)}{x}\ dx}_{x^2\mapsto x}\\-\underbrace{\frac12\int_0^1\frac{\ln^4\left(\frac{1-x}{1+x}\right)}{x}\ dx}_{\frac{1-x}{1+x}\mapsto x}-\underbrace{\int_0^1\frac{\ln^3\left(\frac{1-x}{1+x}\right)\ln(1+x)}{x}\ dx}_{\frac{1-x}{1+x}\mapsto x}$$
$$I=\frac54\underbrace{\int_0^1\frac{\ln^4(1-x)}{x}\ dx}_{4!\zeta(5)}-\underbrace{\int_0^1\frac{\ln^4(1+x)}{x}\ dx}_{K}-\underbrace{\int_0^1\frac{\ln^4x}{1-x^2}\ dx}_{\frac{93}{4}\zeta(5)}+\underbrace{2\int_0^1\frac{\ln^3x\ln\left(\frac{1+x}{2}\right)}{1-x^2}\ dx}_{J}$$
$$I=\frac{27}{4}\zeta(5)-K+J\tag{4}$$
we have
\begin{align} K&=\int_0^1\frac{\ln^4(1+x)}{x}=\int_{1/2}^1\frac{\ln^4x}{x}\ dx+\int_{1/2}^1\frac{\ln^4x}{1-x}\ dx\\ &=\frac15\ln^52+\sum_{n=1}^\infty\int_{1/2}^1 x^{n-1}\ln^4x\ dx\\ &=\frac15\ln^52+\sum_{n=1}^\infty\left(\frac{24}{n^5}-\frac{24}{n^52^n}-\frac{24\ln2}{n^42^n}-\frac{12\ln^22}{n^32^n}-\frac{4\ln^32}{n^22^n}-\frac{\ln^42}{n2^n}\right)\\ &=4\ln^32\zeta(2)-\frac{21}2\ln^22\zeta(3)+24\zeta(5)-\frac45\ln^52-24\ln2\operatorname{Li}_4\left(\frac12\right)-24\operatorname{Li}_5\left(\frac12\right) \end{align}
and
$$J=2\int_0^1\frac{\ln^3x\ln\left(\frac{1+x}{2}\right)}{1-x^2}\ dx=\int_0^1\frac{\ln^3x\ln\left(\frac{1+x}{2}\right)}{1-x}\ dx+\int_0^1\frac{\ln^3x\ln\left(\frac{1+x}{2}\right)}{1+x}\ dx$$
using the rule
$$\int_0^1\frac{\ln^ax\ln\left(\frac{1+x}{2}\right)}{1-x}\ dx=(-1)^aa!\sum_{n=1}^\infty\frac{(-1)^nH_n^{a+1}}{n}$$
allows us to write
\begin{align} J&=-6\sum_{n=1}^\infty\frac{(-1)^nH_n^{(4)}}{n}+\int_0^1\frac{\ln^3x\ln(1+x)}{1+x}\ dx-\ln2\int_0^1\frac{\ln^3x}{1+x}\ dx\\ &=-6\sum_{n=1}^\infty\frac{(-1)^nH_n^{(4)}}{n}-\sum_{n=1}^\infty(-1)^n H_n\int_0^1x^n\ln^3x\ dx-\ln2\left(-\frac{21}4\zeta(4)\right)\\ &=-6\sum_{n=1}^\infty\frac{(-1)^nH_n^{(4)}}{n}+6\sum_{n=1}^\infty\frac{(-1)^n H_n}{(n+1)^4}+\frac{21}{4}\ln2 \zeta(4)\\ &=-6\sum_{n=1}^\infty\frac{(-1)^nH_n^{(4)}}{n}-6\sum_{n=1}^\infty\frac{(-1)^n H_n}{n^4}-\frac{45}{8}\zeta(5)+\frac{21}{4}\ln2 \zeta(4) \end{align}
Plugging
$$\sum_{n=1}^\infty\frac{(-1)^nH_n^{(4)}}{n}=\frac78\ln2\zeta(4)+\frac38\zeta(2)\zeta(3)-2\zeta(5)$$
we get
$$J=\frac{279}{16}\zeta(5)-\frac{21}{4}\zeta(2)\zeta(3)$$
Plugging the results of $$K$$ and $$J$$ in (4) we get
$$\boxed{\small{I=24\operatorname{Li}_5\left(\frac12\right)+24\ln2\operatorname{Li}_4\left(\frac12\right)+\frac3{16}\zeta(5)-\frac{21}{4}\zeta(2)\zeta(3)+\frac{21}2\ln^22\zeta(3)-4\ln^32\zeta(2)+\frac45\ln^52}}$$
and finally by substituting the boxed results in (3) we get
$$\sum _{n=1}^{\infty } \frac{H_{2 n}H_n^2 }{(2 n)^2} =\frac{9 }{16}\zeta (2) \zeta (3)+\frac{421 }{64}\zeta (5)+\frac{2}{3} \ln ^3(2)\zeta (2) -\frac{7}{4} \ln ^2(2)\zeta (3)\\ -\frac{2}{15} \ln^5(2) -4 \ln2\operatorname{Li}_4\left(\frac{1}{2}\right) -4 \operatorname{Li}_5\left(\frac{1}{2}\right)$$
Note:
$$\sum_{n=1}^\infty\frac{(-1)^nH_n}{n^4}$$ can be found here and $$\sum_{n=1}^\infty\frac{(-1)^nH_n^{(4)}}{n}$$ can be found here.
• (+1) Thanks. However, I specified clearly that I only need references. – user97357329 Sep 9 at 11:26
• Thank you and sorry I didnt read that part. – Ali Shather Sep 9 at 14:08
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http://maikolsolis.com/tag/sticky/
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## Regularization on high dimensional covariance matrices
Motivation I remember one lecture about linear models in the University of Costa Rica. He said before to present some classic method “This only works if you have more data than variables”. In this moment, it seems very reasonable and I could not imagine any real case with more variables ($p$) than data ($n$).
## Paper’s review: Zhu & Fang, 1996. Asymptotics for kernel estimate of sliced inverse regression.
It is already known, that for $latex { Y\in {\mathbb R} }&fg=000000$ and $latex { X \in {\mathbb R}^{p} }&fg=000000$, the regression problem $latex \displaystyle Y = f(\mathbf{X}) + \varepsilon, &fg=000000$ when $latex { p }&fg=000000$ is larger than the data available, it is well-known that the curse of dimensionality problem arises. Richard E. Bellman […]
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https://forum.math.toronto.edu/index.php?PHPSESSID=5htdknalpdoamf6v2neoghfad6&action=profile;area=showposts;sa=messages;u=248
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### Show Posts
This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.
### Messages - Mark Kazakevich
Pages: [1]
1
##### MAT244 Misc / Exam Format/Coverage
« on: December 11, 2013, 05:44:38 PM »
Will the format of the exam be similar to past finals? Or will we be tested on much different course material?
2
##### Quiz 3 / Re: Problem 1 (Day section)
« on: November 07, 2013, 12:36:03 PM »
For the differential equation:
$$y^{(6)} - y''$$
We assume that $y = e^{rt}$.
Therefore, we must solve the characteristic equation:
$$r^6 - r^2 = 0$$
We find:
$r^6 - r^2 = 0 \implies r^2(r^4-1) \implies r^2(r^2+1)(r^2-1) = 0 \implies r^2(r^2+1)(r-1)(r+1) = 0$
This means the roots of this equation are:
$r_1 = 0, r_2=0, r_3=i, r_4=-i, r_5=1,r_6=-1$
(We have a repeated root at r = 0)
So the general solution to (1) is:
$$y(t) = c_1 + c_2t + c_3\cos{t} + c_4\sin{t} + c_5e^{t} + c_6e^{-t}$$
3
##### Quiz 3 / Re: Problem 1 (night sections)
« on: November 06, 2013, 08:33:04 PM »
For the differential equation:
$$y'''-y''-y'+y=0$$
We assume that $y = e^{rt}$.
Therefore, we must solve the characteristic equation:
$$r^3 - r^2 - r + 1 = 0$$
We find:
$r^3 - r^2 - r + 1 = 0 \implies (r^2-1)(r-1) = 0 \implies (r+1)(r-1)^2 = 0$
This means the roots of this equation are:
$r_1 = 1, r_2=1, r_3=-1$
(We have a repeated root at r = 1)
So the general solution to (1) is:
$$y(t) = c_1e^{t} + c_2e^{t}t + c_3e^{-t}$$
4
##### MAT244 Misc / Re: duration of quiz1
« on: October 01, 2013, 02:07:30 AM »
Is the quiz at the beginning of the lecture?
Pages: [1]
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http://mathwiki.cs.ut.ee/probability_theory
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# Probability theory
Quite often in life we do not know for sure, what will be the result of an experiment or a process. For example, some hacker tries to attacks a particular information system.
Surely both, the attacker and the information system owner wants to know the risks. So how to describe, what is going to happen? The answer to this gives probability theory.
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https://doc.sagemath.org/html/en/reference/noncommutative_polynomial_rings/sage/rings/polynomial/skew_polynomial_ring.html
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# Skew Univariate Polynomial Rings¶
This module provides the SkewPolynomialRing. In the class hierarchy in Sage, the locution Skew Polynomial is used for a Ore polynomial without twisting derivation.
This module also provides:
AUTHOR:
• Xavier Caruso (2012-06-29): initial version
• Arpit Merchant (2016-08-04): improved docstrings, fixed doctests and refactored classes and methods
• Johan Rosenkilde (2016-08-03): changes for bug fixes, docstring and doctest errors
class sage.rings.polynomial.skew_polynomial_ring.SectionSkewPolynomialCenterInjection
Section of the canonical injection of the center of a skew polynomial ring into this ring.
class sage.rings.polynomial.skew_polynomial_ring.SkewPolynomialCenterInjection(domain, codomain, embed, order)
Canonical injection of the center of a skew polynomial ring into this ring.
section()
Return a section of this morphism.
EXAMPLES:
sage: k.<a> = GF(5^3)
sage: S.<x> = SkewPolynomialRing(k, k.frobenius_endomorphism())
sage: Z = S.center()
sage: iota = S.convert_map_from(Z)
sage: sigma = iota.section()
sage: sigma(x^3)
z
class sage.rings.polynomial.skew_polynomial_ring.SkewPolynomialRing(base_ring, morphism, derivation, name, sparse, category=None)
Initialize self.
INPUT:
• base_ring – a commutative ring
• twisting_morphism – an automorphism of the base ring
• name – string or list of strings representing the name of the variables of ring
• sparse – boolean (default: False)
• category – a category
EXAMPLES:
sage: R.<t> = ZZ[]
sage: sigma = R.hom([t+1])
sage: S.<x> = SkewPolynomialRing(R,sigma)
sage: S.category()
Category of algebras over Univariate Polynomial Ring in t over Integer Ring
sage: S([1]) + S([-1])
0
sage: TestSuite(S).run()
lagrange_polynomial(points)
Return the minimal-degree polynomial which interpolates the given points.
More precisely, given $$n$$ pairs $$(x_1, y_1), \ldots, (x_n, y_n) \in R^2$$, where $$R$$ is self.base_ring(), compute a skew polynomial $$p(x)$$ such that $$p(x_i) = y_i$$ for each $$i$$, under the condition that the $$x_i$$ are linearly independent over the fixed field of self.twisting_morphism().
If the $$x_i$$ are linearly independent over the fixed field of self.twisting_morphism() then such a polynomial is guaranteed to exist. Otherwise, it might exist depending on the $$y_i$$, but the algorithm used in this implementation does not support that, and so an error is always raised.
INPUT:
• points – a list of pairs $$(x_1, y_1), \ldots, (x_n, y_n)$$ of elements of the base ring of self; the $$x_i$$ should be linearly independent over the fixed field of self.twisting_morphism()
OUTPUT:
The Lagrange polynomial.
EXAMPLES:
sage: k.<t> = GF(5^3)
sage: Frob = k.frobenius_endomorphism()
sage: S.<x> = k['x',Frob]
sage: points = [(t, 3*t^2 + 4*t + 4), (t^2, 4*t)]
sage: d = S.lagrange_polynomial(points); d
x + t
sage: R.<t> = ZZ[]
sage: sigma = R.hom([t+1])
sage: T.<x> = R['x', sigma]
sage: points = [ (1, t^2 + 3*t + 4), (t, 2*t^2 + 3*t + 1), (t^2, t^2 + 3*t + 4) ]
sage: p = T.lagrange_polynomial(points); p
((-t^4 - 2*t - 3)/-2)*x^2 + (-t^4 - t^3 - t^2 - 3*t - 2)*x + (-t^4 - 2*t^3 - 4*t^2 - 10*t - 9)/-2
sage: p.multi_point_evaluation([1, t, t^2]) == [ t^2 + 3*t + 4, 2*t^2 + 3*t + 1, t^2 + 3*t + 4 ]
True
If the $$x_i$$ are linearly dependent over the fixed field of self.twisting_morphism(), then an error is raised:
sage: T.lagrange_polynomial([ (t, 1), (2*t, 3) ])
Traceback (most recent call last):
...
ValueError: the given evaluation points are linearly dependent over the fixed field of the twisting morphism,
so a Lagrange polynomial could not be determined (and might not exist)
minimal_vanishing_polynomial(eval_pts)
Return the minimal-degree, monic skew polynomial which vanishes at all the given evaluation points.
The degree of the vanishing polynomial is at most the length of eval_pts. Equality holds if and only if the elements of eval_pts are linearly independent over the fixed field of self.twisting_morphism().
• eval_pts – list of evaluation points which are linearly independent over the fixed field of the twisting morphism of the associated skew polynomial ring
OUTPUT:
The minimal vanishing polynomial.
EXAMPLES:
sage: k.<t> = GF(5^3)
sage: Frob = k.frobenius_endomorphism()
sage: S.<x> = k['x',Frob]
sage: eval_pts = [1, t, t^2]
sage: b = S.minimal_vanishing_polynomial(eval_pts); b
x^3 + 4
The minimal vanishing polynomial evaluates to 0 at each of the evaluation points:
sage: eval = b.multi_point_evaluation(eval_pts); eval
[0, 0, 0]
If the evaluation points are linearly dependent over the fixed field of the twisting morphism, then the returned polynomial has lower degree than the number of evaluation points:
sage: S.minimal_vanishing_polynomial([t])
x + 3*t^2 + 3*t
sage: S.minimal_vanishing_polynomial([t, 3*t])
x + 3*t^2 + 3*t
class sage.rings.polynomial.skew_polynomial_ring.SkewPolynomialRing_finite_field(base_ring, morphism, derivation, names, sparse, category=None)
A specialized class for skew polynomial rings over finite fields.
Todo
Add methods related to center of skew polynomial ring, irreducibility, karatsuba multiplication and factorization.
class sage.rings.polynomial.skew_polynomial_ring.SkewPolynomialRing_finite_order(base_ring, morphism, derivation, name, sparse, category=None)
A specialized class for skew polynomial rings whose twising morphism has finite order.
center(name=None, names=None, default=False)
Return the center of this skew polynomial ring.
Note
If $$F$$ denotes the subring of $$R$$ fixed by $$\sigma$$ and $$\sigma$$ has order $$r$$, the center of $$K[x,\sigma]$$ is $$F[x^r]$$, that is a univariate polynomial ring over $$F$$.
INPUT:
• name – a string or None (default: None); the name for the central variable (namely $$x^r$$)
• default – a boolean (default: False); if True, set the default variable name for the center to name
EXAMPLES:
sage: k.<t> = GF(5^3)
sage: Frob = k.frobenius_endomorphism()
sage: S.<x> = k['x',Frob]; S
Ore Polynomial Ring in x over Finite Field in t of size 5^3 twisted by t |--> t^5
sage: Z = S.center(); Z
Univariate Polynomial Ring in z over Finite Field of size 5
sage: Z.gen()
z
We can pass in another variable name:
sage: S.center(name='y')
Univariate Polynomial Ring in y over Finite Field of size 5
or use the bracket notation:
sage: Zy.<y> = S.center(); Zy
Univariate Polynomial Ring in y over Finite Field of size 5
sage: y.parent() is Zy
True
A coercion map from the center to the skew polynomial ring is set:
sage: S.has_coerce_map_from(Zy)
True
sage: P = y + x; P
x^3 + x
sage: P.parent()
Ore Polynomial Ring in x over Finite Field in t of size 5^3 twisted by t |--> t^5
sage: P.parent() is S
True
together with a conversion map in the reverse direction:
sage: Zy(x^6 + 2*x^3 + 3)
y^2 + 2*y + 3
sage: Zy(x^2)
Traceback (most recent call last):
...
ValueError: x^2 is not in the center
Two different skew polynomial rings can share the same center:
sage: S1.<x1> = k['x1', Frob]
sage: S2.<x2> = k['x2', Frob]
sage: S1.center() is S2.center()
True
About the default name of the central variable
A priori, the default is z.
However, a variable name is given the first time this method is called, the given name become the default for the next calls:
sage: K.<t> = GF(11^3)
sage: phi = K.frobenius_endomorphism()
sage: A.<X> = K['X', phi]
sage: C.<u> = A.center() # first call
sage: C
Univariate Polynomial Ring in u over Finite Field of size 11
sage: A.center() # second call: the variable name is still u
Univariate Polynomial Ring in u over Finite Field of size 11
sage: A.center() is C
True
We can update the default variable name by passing in the argument default=True:
sage: D.<v> = A.center(default=True)
sage: D
Univariate Polynomial Ring in v over Finite Field of size 11
sage: A.center()
Univariate Polynomial Ring in v over Finite Field of size 11
sage: A.center() is D
True
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https://wiki.analytica.com/index.php?title=Correlate_With
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# Correlate With
## Correlate_With(S, ReferenceS, rankCorr)
Used to specify a distribution having a specified rank correlation with a reference distribution. «S» is the marginal distribution of the result. «ReferenceS» is the reference distribution.
Reorders the samples of «S» so that the result is correlated with the reference sample with a rank correlation close to «rankCorr».
## Library
Multivariate Distributions library functions (Multivariate Distributions.ana)
## Example
To generate a LogNormal distribution that is highly correlation with Ch1 (which may be any distribution), use e.g.:
Correlate_With(LogNormal(2, 3), Ch1, 0.8)
## Notes
Most commonly, when the term "correlation" is used, it is implied to mean Pearson Correlation, which is essentially a measure of linearity. Creating a distribution with this measure of correlation makes most sense when the joint distribution is Gaussian, i.e., each marginal distribution is Normal. In this case, you can specify the mean and variance of each variable, and the covariance for each pair of variables, and use the Gaussian function (found in the Multivariate Distribution library) to define the joint distribution. The covariance of two random variables is the correlation of the two variables times the product of their standard deviations, so the Gaussian can be defined directly in terms of Pearson Correlations. The BiNormal function may also be used when defining a 2-D Gaussian.
For non-Gaussian distributions, it is not necessarily possible for two distributions to have a desired Pearson correlation. However, we can ensure a given Rank Correlation, also called Spearman correlation. This is what Correlate_With and Correlate_Dists use.
Correlate_With is the most convenient way for specifying two univariate distributions with a given rank correlation. If you have three or more distributions that are mutually correlated, then you will need a symmetric matrix of rank correlations, and will need to use the Correlate_Dists function.
## Precision
The actual sample rank correlation of the sample generated will differ slightly from the requested rank correlation, due to the fact that the samples have a finite number of points. This sampling error reduces as you increase sample size. The standard deviation of this sampling error (i.e., of the difference between the sample rank correlation and the requested rank correlation) is
$se = \sqrt{ {1-rc^2}\over{n-2} }$
where n is the sample size and rc is the requested rank correlation. For example, when using a sample size of n = 100 and rc = 0.7, we expect a sampling error in actual rank correlation of 0.07. There is therefore about 68% chance that the rank correlation of the samples will be between 0.63 and 0.77, but also a 5% chance it might be less than 0.56 or greater than 0.84.
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https://weblib.cern.ch/collection/ATLAS%20Conference%20Slides?ln=de&as=1
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# CERN Accelerating science
The ATLAS Conference Slides collection contains transparencies on ATLAS that have been presented at conferences. More information about conferences can be found on the external ATLAS Talks at International Physics Conferences webpage.
SUBMIT ATLAS SLIDE
# ATLAS Conference Slides
Letzte Einträge:
2022-12-07
18:18
LHC-HH: Outlook and Plans / Manzoni, Stefano (CERN) /ATLAS Collaboration LHC-HH: Outlook and Plans ATL-PHYS-SLIDE-2022-639.- Geneva : CERN, 2022 Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2022-12-07
10:17
ATLAS Di-Higgs experimental summary / Balunas, William Keaton (University of Cambridge (GB)) /ATLAS Collaboration This talk presents a brief summary of the current status of experimental searches for Higgs boson pair production at ATLAS. A selection of recent results is highlighted, including the first search for VHH production and the combination of HH analyses with single-Higgs channels.. ATL-PHYS-SLIDE-2022-638.- Geneva : CERN, 2022 Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2022-12-07
10:14
Modelling of loop-induced $ZH$-production in ATLAS / Windischhofer, Philipp (University of Chicago (US)) /ATLAS Collaboration This talk presents and compares Monte Carlo generator predictions for the loop-induced production of a Higgs boson $H$ in association with a Z boson that are used in ATLAS. Two separate matrix element calculations of the loop-induced $ZH$ process with up to one additional jet are performed at leading order in the strong coupling constant and matched to parton showers, using Sherpa and MadGraph_aMC@NLO+Pythia 8. [...] ATL-PHYS-SLIDE-2022-637.- Geneva : CERN, 2022 Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2022-12-07
10:08
Summary of Exotic Higgs Decays Results / Coelho Lopes De Sa, Rafael (University of Massachusetts (US)) /ATLAS Collaboration We review recent theory and experimental results related to exotic Higgs decays.. ATL-PHYS-SLIDE-2022-636.- Geneva : CERN, 2022 Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : 17th Workshop of the LHC Higgs Working Group, CERN, Switzerland, 9 - 11 Nov 2020
2022-12-07
10:06
Dark matter searches at LHC (SUSY dark matters) / Chen, Shion (University of Tokyo (JP)) /ATLAS Collaboration SUSY dark matter - specifically electroweakinos - have been the leading candidate of the WIMP dark matter as well as the significant cause of the "WIMP miracle" excitement. While the search for the direct production is challenging due to the small production cross-section compared with the strongly-produced SUSYs, the large data sample size and the new search techniques in LHC Run2 starts to overcome the bottleneck, enabling one to probe drastically heavier electroweakinos these years. [...] ATL-PHYS-SLIDE-2022-635.- Geneva : CERN, 2022 - 44 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2022-12-07
10:03
Overview of VH WG1 experimental/theory status / Arnold, Hannah (Nikhef National institute for subatomic physics (NL)) /ATLAS Collaboration Overview of the work within the LHC Higgs WG WG1 VH subgroup; experimental/theory status.. ATL-PHYS-SLIDE-2022-634.- Geneva : CERN, 2022 Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2022-12-07
09:58
Searches for Dark Matter and Extra Dimensions with the ATLAS Experiment at the LHC / Verducci, Monica (Universita & INFN Pisa (IT)) /ATLAS Collaboration The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. [...] ATL-PHYS-SLIDE-2022-633.- Geneva : CERN, 2022 Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2022-12-06
13:57
Higgs boson property measurements at the ATLAS experiment / Iakovidis, George (Brookhaven National Laboratory (US)) /ATLAS Collaboration Very detailed measurements of Higgs boson properties can be performed with the Run 2 13 TeV pp collision dataset collected by the ATLAS experiment. This talk presents a review of the latest measurements of the Higgs boson properties, including its mass, CP, differential cross-sections . [...] ATL-PHYS-SLIDE-2022-632.- Geneva : CERN, 2022 - 17 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS) In : KRUGER 2022, Skukuza, Za, 4 - 9 Dec 2022
2022-12-05
19:05
Differential measurements of W and Z bosons, and Drell-Yan / Laurier, Alexandre (Technion- Israel Institute of Technology (IL)) /ATLAS Collaboration Measurements of Drell-Yan and W/Z-boson production in association with jets are an important test of electroweak and perturbative QCD predictions. Differential cross sections for Z-boson production, Z-boson production in association with jets and W-boson + a charm quark are presented from ATLAS and CMS. [...] ATL-PHYS-SLIDE-2022-631.- Geneva : CERN, 2022 - 26 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
2022-12-05
14:34
Dark Matter Searches at the LHC / Frost, James (University of Oxford (GB)) /ATLAS Collaboration The presence of a non-baryonic Dark Matter (DM) component in the Universe has been inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the Large Hadron Collider (LHC) experiments, escaping the detector and leaving a large missing transverse momentum as its signature. [...] ATL-PHYS-SLIDE-2022-630.- Geneva : CERN, 2022 - 28 p. Fulltext: PDF; External link: Original Communication (restricted to ATLAS)
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1
PubMed
The oncogenic human papillomavirus (HPV) E6/E7 proteins are essential for the onset and maintenance of HPV-associated malignancies. Here, we report that activation of the cellular ubiquitin-proteasome system (UPS) by the omega-3 fatty acid, docosahexaenoic acid (DHA), leads to proteasome-mediated degradation of E6/E7 viral proteins and the induction of apoptosis in HPV-infected cancer cells. The increases in UPS activity and degradation of E6/E7 oncoproteins were associated with DHA-induced overproduction of mitochondrial reactive oxygen species (ROS). Exogenous oxidative stress and pharmacological induction of mitochondrial ROS showed effects similar to those of DHA, and inhibition of ROS production abolished UPS activation, E6/E7 viral protein destabilization, and apoptosis. These findings identify a novel role for DHA in the regulation of UPS and viral proteins, and provide evidence for the use of DHA as a mechanistically unique anticancer agent for the chemoprevention and treatment of HPV-associated tumors. PMID:25393480
Jing, K; Shin, S; Jeong, S; Kim, S; Song, K-S; Park, J-H; Heo, J-Y; Seo, K-S; Park, S-K; Kweon, G-R; Wu, T; Park, J-I; Lim, K
2014-01-01
2
PubMed Central
The human papillomavirus (HPV) E7 oncoprotein shares functional similarities with such proteins as adenovirus E1A and SV40 large tumor antigen. As one of only two viral proteins always expressed in HPV-associated cancers, E7 plays a central role in both the viral life cycle and carcinogenic transformation. In the HPV viral life cycle, E7 disrupts the intimate association between cellular differentiation and proliferation in normal epithelium, allowing for viral replication in cells that would no longer be in the dividing population. This function is directly reflected in the transforming activities of E7, including tumor initiation and induction of genomic instability. PMID:19007963
McLaughlin-Drubin, Margaret E.; Münger, Karl
2009-01-01
3
PubMed Central
Human papillomavirus type 16 (HPV16) and other oncogenic viruses have been reported to deregulate immunity by suppressing the function of the double-stranded DNA innate sensor TLR9. However, the mechanisms leading to these events remain to be elucidated. We show that infection of human epithelial cells with HPV16 promotes the formation of an inhibitory transcriptional complex containing NF-?Bp50–p65 and ER? induced by the E7 oncoprotein. The E7-mediated transcriptional complex also recruited the histone demethylase JARID1B and histone deacetylase HDAC1. The entire complex bound to a specific region on the TLR9 promoter, which resulted in decreased methylation and acetylation of histones upstream of the TLR9 transcriptional start site. The involvement of NF-?B and ER? in the TLR9 down-regulation by HPV16 E7 was fully confirmed in cervical tissues from human patients. Importantly, we present evidence that the HPV16-induced TLR9 down-regulation affects the interferon response which negatively regulates viral infection. Our studies highlight a novel HPV16-mediated mechanism that combines epigenetic and transcriptional events to suppress a key innate immune sensor. PMID:23752229
Zannetti, Claudia; Parroche, Peggy; Goutagny, Nadège; Malfroy, Marine; Roblot, Guillaume; Carreira, Christine; Hussain, Ishraq; Müller, Martin; Taylor-Papadimitriou, Joyce; Picard, Didier; Sylla, Bakary S.; Trinchieri, Giorgio; Medzhitov, Ruslan
2013-01-01
4
PubMed Central
The genome organization of the novel human papillomavirus type 108 (HPV108), isolated from a low-grade cervical lesion, deviates from those of other HPVs in lacking an E6 gene. The three related HPV types HPV103, HPV108, and HPV101 were isolated from cervicovaginal cells taken from normal genital mucosa (HPV103) and low-grade (HPV108) and high-grade cervical (HPV101) intraepithelial neoplasia (Z. Chen, M. Schiffman, R. Herrero, R. DeSalle, and R. D. Burk, Virology 360:447-453, 2007, and this report). Their unusual genome organization, against the background of considerable phylogenetic distance from the other HPV types usually associated with lesions of the genital tract, prompted us to investigate whether HPV108 E7 per se is sufficient to induce the above-mentioned clinical lesions. Expression of HPV108 E7 in organotypic keratinocyte cultures increases proliferation and apoptosis, focal nuclear polymorphism, and polychromasia. This is associated with irregular intra- and extracellular lipid accumulation and loss of the epithelial barrier. These alterations are linked to HPV108 E7 binding to pRb and inducing its decrease, an increase in PCNA expression, and BrdU incorporation, as well as increased p53 and p21CIP1 protein levels. A delay in keratin K10 expression, increased expression of keratins K14 and K16, and loss of the corneal proteins involucrin and loricrin have also been noted. These modifications are suggestive of infection by a high-risk papillomavirus. PMID:19153227
Nobre, Rui Jorge; Herráez-Hernández, Elsa; Fei, Jian-Wei; Langbein, Lutz; Kaden, Sylvia; Gröne, Hermann-Josef; de Villiers, Ethel-Michele
2009-01-01
5
PubMed
Despite the availability of vaccines, human papillomavirus (HPV) infections remain a cause of significant cancer morbidity and mortality. We have previously shown that HPV16 E7 associates with and diminishes E2F6-containing polycomb repressive complexes. Here, we show that repressive trimethyl marks on lysine 27 of histone 3, which are necessary for binding of polycomb repressive complexes, are decreased in HPV16 E7-expressing cells and HPV16-positive cervical lesions. This is caused by transcriptional induction of the KDM6A and KDM6B histone 3 lysine 27-specific demethylases. HPV16 E7-mediated KDM6B induction accounts for expression of the cervical cancer biomarker, p16(INK4A). Moreover, KDM6A- and KDM6B-responsive Homeobox genes are expressed at significantly higher levels, suggesting that HPV16 E7 results in reprogramming of host epithelial cells. These effects are independent of the ability of E7 to inhibit the retinoblastoma tumor suppressor protein. Most importantly, these effects are reversed when E7 expression is silenced, indicating that this pathway may have prognostic and/or therapeutic significance. PMID:21245294
McLaughlin-Drubin, Margaret E; Crum, Christopher P; Münger, Karl
2011-02-01
6
PubMed
Our previous studies on cutaneous beta human papillomavirus 38 (HPV38) E6 and E7 oncoproteins highlighted a novel activity of I?B kinase beta (IKK?) in the nucleus of human keratinocytes, where it phosphorylates and stabilizes ?Np73?, an antagonist of p53/p73 functions. Here, we further characterize the role of the IKK? nuclear form. We show that IKK? nuclear translocation and ?Np73? accumulation are mediated mainly by HPV38 E7 oncoprotein. Chromatin immunoprecipitation (ChIP)/Re-ChIP experiments showed that ?Np73? and IKK? are part, together with two epigenetic enzymes DNA methyltransferase 1 (DNMT1) and the enhancer of zeste homolog 2 (EZH2), of a transcriptional regulatory complex that inhibits the expression of some p53-regulated genes, such as PIG3. Recruitment to the PIG3 promoter of EZH2 and DNMT1 resulted in trimethylation of histone 3 on lysine 27 and in DNA methylation, respectively, both events associated with gene expression silencing. Decreases in the intracellular levels of HPV38 E7 or ?Np73? strongly affected the recruitment of the inhibitory transcriptional complex to the PIG3 promoter, with consequent restoration of p53-regulated gene expression. Finally, the ?Np73?/IKK?/DNMT1/EZH2 complex appears to bind a subset of p53-regulated promoters. In fact, the complex is efficiently recruited to several promoters of genes encoding proteins involved in DNA repair and apoptosis, whereas it does not influence the expression of the prosurvival factor Survivin. In summary, our data show that HPV38 via E7 protein promotes the formation of a multiprotein complex that negatively regulates the expression of several p53-regulated genes. PMID:24006445
Saidj, Djamel; Cros, Marie-Pierre; Hernandez-Vargas, Hector; Guarino, Francesca; Sylla, Bakary S; Tommasino, Massimo; Accardi, Rosita
2013-11-01
7
The human papillomavirus E7 oncoprotein binds to the retinoblastoma (Rb) tumor suppressor protein, and the binding to Rb correlates with the oncogenic potential of E7. Recent studies from several laboratories indicated that the half-life of the Rb protein is reduced in cells that are stably transformed with E7, suggesting that E7 could induce the proteolytic degradation of Rb. To investigate
Ekaterena Berezutskaya; Bo Yu; Alexei Morozov; Pradip Raychaudhuri; Srilata Bagchi
1997-01-01
8
PubMed Central
Murine L1Md-A5 retrotransposon is a redox-inducible element regulated by Nrf-2/JunD and E2F/Rb-binding sites within its promoter (5?-UTR). Because the human papillomavirus (HPV) oncoprotein E7 interacts with retinoblastoma (pRb) and members of the AP1 family, studies were conducted to examine functional interactions between HPV E7, pRb, and histone deacetylase 2 (HDAC2) in the regulation of L1Md-A5. Using a transient heterologous transcription system we found that HPV E7 alone, or in combination with HDAC2, disrupted pRb-mediated L1MdA-5 transactivation. HPV E7 also ablated the transcriptional response of L1Md-A5 to genotoxic stress, but did not interfere with basal activity. We conclude that HPV E7 associates with proteins involved in the assembly of macromolecular complexes that regulate antioxidant and E2F/Rb sites within L1MdA-5 to regulate biological activity PMID:22172279
Montoya-Durango, Diego E.; Ramos, Kenneth S.
2012-01-01
9
PubMed
We recently determined that the nuclear import of cutaneous beta genus HPV8 E7 oncoprotein it is mediated by its zinc-binding domain via direct hydrophobic interactions with the FG nucleoporins Nup62 and Nup153 (Onder and Moroianu, 2014). Here we investigated the nuclear export of HPV8 E7 oncoprotein using confocal microscopy after transfections of HeLa cells with EGFP-8cE7 and mutant plasmids and treatment with Ratjadone A nuclear export inhibitor. We determined that HPV8 E7 contains a leucine-rich nuclear export signal (NES), 76IRTFQELLF84, within its zinc-binding domain that mediates its nuclear export via a CRM1 pathway. We found that HPV8 E7 interacts with CRM1 and that the hydrophobic amino acid residues I76, F79 and L82 of the NES are essential for this interaction and for nuclear export of HPV8 E7 oncoprotein. PMID:25463601
Onder, Zeynep; Chang, Vivian; Moroianu, Junona
2015-01-01
10
PubMed Central
ABSTRACT Human papillomavirus (HPV) can successfully evade the host immune response to establish a persistent infection. We show here that expression of the E7 oncoprotein in primary human keratinocytes results in increased production of interleukin-18 (IL-18) binding protein (IL-18BP). This anti-inflammatory cytokine binding protein is a natural antagonist of IL-18 and is necessary for skin homeostasis. We map increased IL-18BP production to the CR3 region of E7 and demonstrate that this ability is shared among E7 proteins from different HPV types. Furthermore, mutagenesis shows that increased IL-18BP production is mediated by a gamma-activated sequence (GAS) in the IL-18BP promoter. Importantly, the increased IL-18BP levels seen in E7-expressing keratinocytes are capable of diminishing IL-18-mediated CD4 lymphocyte activation. This study provides the first evidence for a virus protein that targets IL-18BP and further validates E7 as a key component of the HPV immune evasion armor. IMPORTANCE Infection with human papillomavirus is a leading cause of morbidity and mortality worldwide. This study demonstrates that the E7 protein increases production of the anti-inflammatory IL-18BP, a major regulator of epithelial homeostasis. A number of E7 proteins can increase IL-18BP production, and a region within the CR3 of E7 is necessary for mediating the increase. A consequence of increased IL-18BP production is a reduction in CD4-positive lymphocyte activation in response to IL-18 costimulation. These findings may shed light on the immune evasion abilities of HPV. PMID:24478434
Richards, Kathryn H.; Doble, Rosella; Wasson, Christopher W.; Haider, Mohammed; Blair, G. Eric; Wittmann, Miriam
2014-01-01
11
PubMed Central
The E7 gene of human papillomavirus type 16 encodes a multifunctional nuclear phosphoprotein that is functionally and structurally similar to the adenovirus (Ad) E1A proteins and the T antigens of other papovaviruses. E7 can cooperate with an activated ras oncogene to transform primary rodent cells, trans activate the Ad E2 promoter, and abrogate transforming growth factor beta-mediated repression of c-myc. Recent studies suggest that these functions may in part be a consequence of the ability of E7 to associate with the product of the retinoblastoma tumor suppressor gene (pRB). In this study, a series of site-specific mutations of the human papillomavirus type 16 E7 gene product were constructed and assessed for their effects on intracellular protein stability, ras cooperativity, transcriptional trans activation, pRB association, and phosphorylation. The results of these studies indicate that the transforming and trans-activating domains extensively overlap within a region of the protein analogous to conserved region 2 of Ad E1A, suggesting that pRB binding is necessary for both activities. Deletion of sequences in conserved region 1 abrogates cellular transformation but has only a marginal effect on trans activation. These data suggest that E7 trans activation and cellular transformation are interrelated but separable functions. Images PMID:1312637
Phelps, W C; Münger, K; Yee, C L; Barnes, J A; Howley, P M
1992-01-01
12
The E7 oncoprotein of the high risk human papillomavirus type 16 (HPV-16), which is etiologically associated with uterine cervical cancer, is a potent immortalizing and transforming agent. It probably exerts its oncogenic functions by interacting and altering the normal activity of cell cycle control proteins such as p21WAF1, p27KIP1 and pRb, transcriptional activators such as TBP and AP-1, and metabolic
Eyal Reinstein; Martin Scheffner; Moshe Oren; Aaron Ciechanover; Alan Schwartz
2000-01-01
13
PubMed
The anaphase promoting complex/cyclosome (APC/C) is a ubiquitin ligase complex that orchestrates mitotic progression by targeting key mitotic regulators for proteasomal degradation. APC/C dysfunction is a frequent event during cancer development and can give rise to genomic instability. Here we report that the HPV16 E7 oncoprotein interferes with the degradation of APC/C substrates and that the APC/C inhibitor, EMI1, is expressed at higher levels in HPV16 E7-expressing mitotic cells. HPV16 E7 expression causes increased EMI1 mRNA expression and also inhibits EMI1 degradation. The resulting abnormally high EMI1 levels in HPV16 E7-expressing mitotic cells may inhibit degradation of APC/C substrates and cause the prometaphase delay that we have previously observed in such cells. PMID:24074588
Yu, Yueyang; Munger, Karl
2013-11-01
14
PubMed
The oncoprotein E7 from human papillomavirus (HPV) strains that confer high cancer risk mediates cell transformation by deregulating host cellular processes and activating viral gene expression through recruitment of cellular proteins such as the retinoblastoma protein (pRb) and the cyclic-AMP response element binding binding protein (CBP) and its paralog p300. Here we show that the intrinsically disordered N-terminal region of E7 from high-risk HPV16 binds the TAZ2 domain of CBP with greater affinity than E7 from low-risk HPV6b. HPV E7 and the tumor suppressor p53 compete for binding to TAZ2. The TAZ2 binding site in E7 overlaps the LxCxE motif that is crucial for interaction with pRb. While TAZ2 and pRb compete for binding to a monomeric E7 polypeptide, the full-length E7 dimer mediates an interaction between TAZ2 and pRb by promoting formation of a ternary complex. Cell-based assays show that expression of full-length HPV16 E7 promotes increased pRb acetylation and that this response depends both on the presence of CBP/p300 and on the ability of E7 to form a dimer. These observations suggest a model for the oncogenic effect of high-risk HPV16 E7. The disordered region of one E7 molecule in the homodimer interacts with the pocket domain of pRb, while the same region of the other E7 molecule binds the TAZ2 domain of CBP/p300. Through its ability to dimerize, E7 recruits CBP/p300 and pRb into a ternary complex, bringing the histone acetyltransferase domain of CBP/p300 into proximity to pRb and promoting acetylation, leading to disruption of cell cycle control. PMID:25451029
Jansma, Ariane L; Martinez-Yamout, Maria A; Liao, Rong; Sun, Peiqing; Dyson, H Jane; Wright, Peter E
2014-12-12
15
Human papilloma viruses (HPVs) are small double-stranded DNA viruses that infect mucosal and cutaneous epithelium and induce cervical cancer. It has been shown that interferon (IFN)? suppresses proliferation of HPV-infected cells by suppressing expression of HPV E7. Here, we found that IFN? induces not only suppression of E7 transcription but also proteasome-dependent degradation. Suppressor of cytokine signaling-1 (SOCS1)\\/JAB, a suppressor
Masaki Kamio; Takafumi Yoshida; Hisanobu Ogata; Tsutomu Douchi; Yukihiro Nagata; Makoto Inoue; Mamoru Hasegawa; Yoshikazu Yonemitsu; Akihiko Yoshimura
2004-01-01
16
RET tyrosine kinase oncoproteins are potential targets for anticancer therapy. We show here that along with the inhibition of RET tyrosine phosphorylation, the pyrazolo-pyrimidine inhibitor PP1 induces RETMEN2A and RETMEN2B oncoprotein destruction. In fact, as a consequence of PP1 treatment, RET oncoproteins translocate from the outer limiting membrane to inner cellular compartments and are rapidly addressed to the degradative pathway.
Cristiana Carniti; Carla Perego; Piera Mondellini; Marco Alessandro Pierotti; Italia Bongarzone
2003-01-01
17
PubMed
We have shown that the expression of human papillomavirus type 16 E7 (HPV16.E7) protein within epithelial cells results in local immune suppression and a weak and ineffective immune response to E7 similar to that occuring in HPV-associated premalignancy and cancers. However, a robust acute inflammatory stimulus can overcome this to enable immune elimination of HPV16.E7-transformed epithelial cells. 2,4-Dinitrochlorobenzene (DNCB) can elicit acute inflammation and it has been shown to initiate the regression of HPV-associated genital warts. Although the clinical use of DNCB is discouraged owing to its mutagenic potential, understanding how DNCB-induced acute inflammation alters local HPV16.E7-mediated immune suppression might lead to better treatments. Here, we show that topical DNCB application to skin expressing HPV16.E7 as a transgene induces a hyperinflammatory response, which is not seen in nontransgenic control animals. The E7-associated inflammatory response is characterized by enhanced expression of Th2 cytokines and increased infiltration of CD11b(+)Gr1(int)F4/80(+)Ly6C(hi)Ly6G(low) myeloid cells, producing arginase-1. Inhibition of arginase with an arginase-specific inhibitor, N(omega)-hydroxy-nor-L-arginine, ameliorates the DNCB-induced inflammatory response. Our results demonstrate that HPV16.E7 protein enhances DNCB-associated production of arginase-1 by myeloid cells and consequent inflammatory cellular infiltration of skin. PMID:24732401
Tran, Le Son; Bergot, Anne-Sophie; Mattarollo, Stephen R; Mittal, Deepak; Frazer, Ian H
2014-09-01
18
Human papilloma virus (HPV)-16 is the most prevalent high-risk mucosal genotype and the expression of the E6 and E7 proteins, which can bind to the p53 and p105Rb host cell-cycle regulatory proteins, is related to its tumorigenicity. Virus-like-particle (VLP)-based immunogens developed recently are successful as prophylactic HPV vaccines. However, given the high number of individuals infected already with HPV and
Eleana Pozzi; Valeria Basavecchia; Carlo Zanotto; Sole Pacchioni; Carlo De Giuli Morghen; Antonia Radaelli
2009-01-01
19
E-print Network
Oncoprotein Akt/PKB induces trophic effects in murine models of Parkinson's disease Vincent Ries an established role in the treatment of human neurodegenerative diseases. One impediment has been the diffi, neurons affected in Parkinson's disease, by adeno-associated virus 1 trans- duction with a gene encoding
Burke, Robert E
20
Alteration of the apoptosis pathway, as well as the presence of human papilloma virus (HPV), has been linked to the proliferative capacity and drug resistant phenotype of SiHa cervical cancer. We investigated the roles of E6 and E7 HPV oncoproteins in the expression of apoptosis regulating genes in cervical cancer cells that contain the characteristics of apoptosis resistance, and also
Saharat Aungsumart
21
PubMed
p300 is a transcriptional coactivator that participates in many important processes in the cell, including proliferation, differentiation, and apoptosis. The viral oncoproteins, adenovirus (Ad) E1A and human papillomavirus (HPV) E7, have been implicated in binding to p300. The Ad-E1A-p300 interaction has been shown to result in the induction of cellular proliferation, epigenetic reprogramming, and cellular transformation and cancer. The HPV-E7-p300 interaction, on the other hand, is not well understood. p300 contains three zinc-binding domains, CH1-CH3, and studies have shown that Ad-E1A can bind to the p300 CH1 and CH3 domains whereas E7 can bind to the CH1 domain and to a lesser extent to the CH2 and CH3 domains. Here we address how high-risk HPV16-E7 and Ad5-E1A, which have different structures, can both bind the p300 CH1 domain. Using pull-down, gel filtration, and analytical ultracentrifugation studies, we show that the N-terminus and CR1 domains of Ad5-E1A and the CR1 and CR2 domains of HPV16-E7 bind to the p300 CH1 domain competitively and with midnanomolar and low micromolar dissociation constants, respectively. We also show that Ad5-E1A can form a ternary complex with the p300 CH1 domain and the retinoblastoma pRb transcriptional repressor, whereas HPV16-E7 cannot. These studies suggest that the HPV16-E7 and Ad5-E1A viral oncoproteins bind to the same p300 CH1 domain to disrupt p300 function by distinct mechanisms. PMID:23121466
Fera, Daniela; Marmorstein, Ronen
2012-11-27
22
PubMed Central
Cells expressing human papillomavirus type 16 (HPV-16) E7, similar to those which express HPV-16 E6, are resistant to a p53-mediated G1 growth arrest. We examined the p53-mediated DNA damage response pathway in E7-expressing cells to determine the mechanism by which E7-containing cells continue to cycle. In response to DNA damage, no dramatic difference was detected in G1- or S-phase cyclin or cyclin-dependent kinase (Cdk) levels when E7-expressing cells were compared to the parental cell line, RKO. Furthermore, Cdk2 kinase activity was inhibited in both RKO cells and E7-expressing cells, while Cdk2 remained active in E6-expressing cells. However, the steady-state levels of pRB and p107 protein were substantially lower in E7-expressing cells than in the parental RKO cells or E6-expressing cells. There was no reduction in pRB mRNA levels, but the half-life of pRB in E7-expressing cells was markedly shorter. Infection of primary human foreskin keratinocytes with recombinant retroviruses expressing HPV-16 E7 resulted in a decrease in pRB protein levels, indicating this phenomenon is a consequence of E7 expression, not of immortalization or transformation. These data strongly suggest E7 interferes with the stability of pRB and p107 protein. We propose that the removal of these components of the p53-mediated G1 growth arrest pathway in E7-expressing cells contributes to the ability of E7 to overcome a p53-mediated G1 growth arrest. PMID:9060648
Jones, D L; Münger, K
1997-01-01
23
PubMed
Increased evidence of chemo-resistance, toxicity and carcinogenicity necessitates search for alternative approaches for determining next generation cancer therapeutics and targets. We therefore tested the efficacy of plant alkaloid berberine on human papilloma virus (HPV) -18 positive cervical cancer cell HeLa systematically-involving certain cellular, viral and epigenetic factors. We observed disruptions of microtubule network and changes in membrane topology due to berberine influx through confocal and atomic force microscopies (AFM). We examined nuclear uptake, internucleosomal DNA damages, mitochondrial membrane potential (MMP) alterations and cell migration assays to validate possible mode of cell death events. Analytical data on interactions of berberine with pBR322 through fourier transform infrared (FTIR) and gel migration assay strengthen berberine?s biologically significant DNA binding abilities. We measured cellular uptake, DNA ploidy and DNA strand-breaks through fluorescence activated cell sorting (FACS). To elucidate epigenetic modifications, in support of DNA binding associated processes, if any, we conducted methylation-specific restriction enzyme (RE) assay, methylation specific-PCR (MSP) and expression studies of histone proteins. We also analyzed differential interactions and localization of cellular tumor suppressor p53 and viral oncoproteins HPV-18 E6-E7 through siRNA approach. We further made in-silico approaches to determine possible binding sites of berberine on histone proteins. Overall results indicated cellular uptake of berberine through cell membrane depolarization causing disruption of microtubule networks and its biological DNA binding abilities that probably contributed to epigenetic modifications. Results of modulation in p53 and viral oncoproteins HPV-18 E6-E7 by berberine further proved its potential as a promising chemotherapeutic agent in cervical cancer. PMID:25448308
Saha, Santu Kumar; Khuda-Bukhsh, Anisur Rahman
2014-12-01
24
PubMed Central
Transgenic mice expressing the E7 protein of HPV16 from the keratin 14 promoter demonstrate increasing thymic hypertrophy with age. This hypertrophy is associated with increased absolute numbers of all thymocyte types, and with increased cortical and medullary cellularity. In the thymic medulla, increased compartmentalization of the major thymic stromal cell types and expansion of thymic epithelial cell population is observed. Neither an increased rate of immature thymocyte division nor a decreased rate of immature thymocyte death was able to account for the observed hypertrophy. Thymocytes with reduced levels of expression of CD4 and/or CD8 were more abundant in transgenic (tg) mice and became increasingly more so with age. These thymic SP and DP populations with reduced levels of CD4 and/or CD8 markers had a lower rate of apoptosis in the tg than in the non-tg mice. The rate of export of mature thymocytes to peripheral lymphoid organs was less in tg animals relative to the pool of available mature cells, particularly for the increasingly abundant CD4lo population. We therefore suggest that mature thymocytes that would normally die in the thymus gradually accumulated in E7 transgenic animals, perhaps as a consequence of exposure to a hypertrophied E7-expressing thymic epithelium or to factors secreted by this expanded thymic stromal cell population. The K14E7 transgenic mouse thus provides a unique model to study effects of the thymic epithelial cell compartment on thymus development and involution. PMID:14768939
Malcolm, K. M.; Gill, J.; Leggatt, G. R.; Boyd, R.; Lambert, P.; Frazer, I. H.
2003-01-01
25
PubMed
The life cycle of human papillomaviruses (HPVs) is strictly linked to the differentiation of their natural host cells. The HPV E6 and E7 oncoproteins can delay the normal differentiation program of keratinocytes; however, the exact mechanisms responsible for this have not yet been identified. The goal of this study was to investigate the effects of HPV16 oncoproteins on the expression of genes involved in keratinocyte differentiation. Primary human keratinocytes transduced by LXSN (control) retroviruses or virus vectors expressing HPV16 E6, E7 or E6/E7 genes were subjected to gene expression profiling. The results of microarray analysis showed that HPV 16 E6 and E7 have the capacity to downregulate the expression of several genes involved in keratinocyte differentiation. Quantitative real-time polymerase chain reaction (qRT-PCR) assays were performed to confirm the microarray data. To investigate the effects of the HPV oncoproteins on the promoters of selected keratinocyte differentiation genes, luciferase reporter assays were performed. Our results suggest that the HPV 16 E6 and/or E7 oncogenes are able to downregulate the expression of several genes involved in keratinocyte differentiation (such as desmocollin 1, keratin 4, S100 calcium-binding protein A8 and small proline-rich protein 1A), at least partially by downregulating their promoter activity. This activity of the HPV oncoproteins may have a role in the productive virus life cycle, and also in virus-induced carcinogenesis. PMID:25488293
Gyöngyösi, Eszter; Szalmás, Anita; Ferenczi, Annamária; Póliska, Szilárd; Kónya, József; Veress, György
2014-12-01
26
SciTech Connect
Interferons (IFNs) exert antitumor effects in several human malignancies, but their mechanism of action is unclear. There is a great variability in sensitivity to IFN treatment depending on both tumor type and the individual patient. The reason for this variable sensitivity is not known. The fact that several IFN-induced anticellular effects are exerted through modulation of proto-oncogenes and tumor suppressor genes may indicate that the malignant genotype may be decisive in the cell's sensitivity to IFN. To determine if a deregulated oncogene could alter the cellular response to IFN, a mouse lymphoma cell line (J3D) was stably transfected with the viral human papillomavirus-16 (HPV-16) E7 oncogene. The E7-transfected cells and their respective mock-transfected sister clones were treated with IFN-{alpha} and examined for possible IFN-induced anticellular effects. We found that the E7-transfected clones were greatly sensitized to IFN-{alpha}-induced apoptosis compared with their mock-transfected counterparts. Induction of apoptosis in the transfected cells correlated with the ability of IFN to activate parts of the proapoptotic machinery specifically in these cells, including activation of caspases and the proapoptotic protein Bak. In summary, our data suggest that transfection of malignant cells with the E7 oncogene can sensitize them to IFN-{alpha}-induced apoptosis. This demonstrates that an oncogenic event may alter the cellular sensitivity to IFN and might also have implications for treatment of HPV related diseases with IFN.
Wang, Yisong [ORNL
2005-10-01
27
PubMed Central
SUMMARY Splicing and translation are highly regulated steps of gene expression. Altered expression of proteins involved in these processes can be deleterious. Therefore, the cell has many safeguards against such misregulation. We report that the oncogenic splicing factor SRSF1, which is overexpressed in many cancers, stabilizes the tumor-suppressor protein p53 by abrogating its MDM2-dependent proteasomal degradation. We show that SRSF1 is a necessary component of an MDM2/ribosomal-protein complex—separate from the ribosome—that functions in a p53-dependent ribosomal-stress checkpoint pathway. Consistent with the stabilization of p53, increased SRSF1 expression in primary human fibroblasts decreases cellular proliferation and ultimately triggers oncogene-induced senescence (OIS). These findings underscore the deleterious outcome of SRSF1 overexpression and identify a cellular defense mechanism against its aberrant function. Furthermore, they implicate the RPL5-MDM2 complex in OIS, and demonstrate a link between spliceosomal and ribosomal components—functioning independently of their canonical roles—to monitor cellular physiology and cell-cycle progression. PMID:23478443
Fregoso, Oliver I.; Das, Shipra; Akerman, Martin; Krainer, Adrian R.
2013-01-01
28
BACKGROUND: Lung cancers consist of four major types that and for clinical-pathological reasons are often divided into two broad categories: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). All major histological types of lung cancer are associated with smoking, although the association is stronger for SCLC and squamous cell carcinoma than adenocarcinoma. To date, epidemiological studies have
Tonia Buonomo; Laura Carraresi; Mara Rossini; Rosanna Martinelli
2011-01-01
29
PubMed Central
The E6 and E7 proteins of high-risk HPVs are both required for the immortalization of primary human keratinocytes and the maintenance of the malignant phenotype of HPV-positive cancer cell lines. Our previous studies have shown that E6 protein binds Myc protein and that both E6 and Myc associate with and cooperatively activate the hTERT promoter, thereby increasing cellular telomerase activity. In this study, we evaluated the role of E7 in the maintenance and activation of telomerase in immortalized and tumorigenic cells. siRNA knockdown of either E6 or E7 (or both) in HPV-immortalized cells or an HPV-positive cancer cell line reduced hTERT transcription and telomerase activity. Since telomerase was inhibited by E7 siRNA in cells that independently expressed the E6 and E7 genes, our results reveal an independent role for E7 in the maintenance of telomerase activity. However, E7 alone was insufficient to increase endogenous hTERT mRNA or telomerase activity, although it significantly augmented E6-induced hTERT transcription and telomerase activity. To further explore this apparent E7-induced promoter augmentation, we analyzed an exogenous hTERT core promoter in transduced keratinocytes. E7 alone induced the wt hTERT promoter and augmented E6-induced hTERT promoter activity. Mutation of the E2F site in the hTERT promoter abrogated the ability of E7 to induce the hTERT promoter or to enhance the ability of E6 to induce the promoter. Correspondingly, keratinocytes expressing E6 and a mutant E7 (defective for binding pRb pocket proteins) showed lower telomerase activity than cells expressing wt E6 and wt E7. Thus, HPV E7 plays a role in the maintenance of telomerase activity in stable cell lines and augments acute, E6-induced hTERT promoter activity. PMID:18367227
Liu, Xuefeng; Roberts, Jeffrey; Dakic, Aleksandra; Zhang, Yiyu; Schlegel, Richard
2009-01-01
30
PubMed
NUT midline carcinoma (NMC) is a rare but highly aggressive cancer typically caused by the translocation t(15;19), which results in the formation of the BRD4-NUT fusion oncoprotein. Previous studies have demonstrated that fusion of the NUT protein with the double bromodomains of BRD4 may significantly alter the cellular gene expression profile to contribute to NMC tumorigenesis. However, the mechanistic details of this BRD4-NUT function remain poorly understood. In this study, we examined the NUT function in transcriptional regulation by targeting it to a LacO transgene array integrated in U2OS 2-6-3 cells, which allow us to visualize how NUT alters the in situ gene transcription dynamic. Using this system, we demonstrated that the NUT protein tethered to the LacO locus recruits p300/CREB-binding protein (CBP), induces histone hyperacetylation, and enriches BRD4 to the transgene array chromatin foci. We also discovered that, in BRD4-NUT expressed in NMC cells, the NUT moiety of the fusion protein anchored to chromatin by the double bromodomains also stimulates histone hyperacetylation, which causes BRD4 to bind tighter to chromatin. Consequently, multiple BRD4-interacting factors are recruited to the NUT-associated chromatin locus to activate in situ transgene expression. This gene transcription function was repressed by either expression of a dominant negative inhibitor of the p300-NUT interaction or treatment with (+)-JQ1, which dissociates BRD4 from the LacO chromatin locus. Our data support a model in which BRD4-NUT-stimulated histone hyperacetylation recruits additional BRD4 and interacting partners to support transcriptional activation, which underlies the BRD4-NUT oncogenic mechanism in NMC. PMID:25512383
Wang, Ranran; You, Jianxin
2015-01-30
31
PubMed Central
Tumor suppressors negatively regulate angiogenesis, an essential step in tumor progression. Together, HPV 16 E6 and E7 proteins, which target p53 and pRb family members, respectively, for degradation, increase the expression of two angiogenic inducers, VEGF and IL-8, in primary foreskin keratinocytes (HFKs). Conditioned media from such cells are sufficient to alter endothelial cell behavior. Here, the individual contribution of E6 and E7 to angiogenesis was investigated. E7 and, to a lesser extent E6, increased expression of VEGF and IL-8. Nevertheless, neither conditioned media from HPV 16 E6 nor E7-expressing HFKs were sufficient to induce migration of endothelial cells. Conditioned media from HFKs expressing the HPV 16 E6 and the E7 mutant E7C24G, which can target p107 and p130 but not pRb for degradation, contained increased levels of VEGF and IL-8. The results suggest that the mechanism of HPV 16 E7-mediated increased levels of VEGF is pRb-independent. PMID:21159359
Walker, Joanna; Smiley, Lucy Clare; Ingram, David; Roman, Ann
2010-01-01
32
PubMed Central
High-risk human papillomavirus (HR-HPV) has been recognized as a major causative agent for cervical cancer. Upon HPV infection, early genes E6 and E7 play important roles in maintaining malignant phenotype of cervical cancer cells. By using clustered regularly interspaced short palindromic repeats- (CRISPR-) associated protein system (CRISPR/Cas system), a widely used genome editing tool in many organisms, to target HPV16-E7 DNA in HPV positive cell lines, we showed for the first time that the HPV16-E7 single-guide RNA (sgRNA) guided CRISPR/Cas system could disrupt HPV16-E7 DNA at specific sites, inducing apoptosis and growth inhibition in HPV positive SiHa and Caski cells, but not in HPV negative C33A and HEK293 cells. Moreover, disruption of E7 DNA directly leads to downregulation of E7 protein and upregulation of tumor suppressor protein pRb. Therefore, our results suggest that HPV16-E7 gRNA guided CRISPR/Cas system might be used as a therapeutic strategy for the treatment of cervical cancer. PMID:25136604
Hu, Zheng; Yu, Lan; Zhu, Da; Ding, Wencheng; Wang, Xiaoli; Zhang, Changlin; Wang, Liming; Jiang, Xiaohui; Shen, Hui; He, Dan; Li, Kezhen; Xi, Ling; Ma, Ding; Wang, Hui
2014-01-01
33
PubMed Central
A critical event in papillomavirus transformation of human cells is the inactivation of pRB by the E7 protein. E7, like many other viral oncoproteins, possesses a well-characterized LXCXE peptide motif that interacts with the pocket domain of pRB. Disruption of the LXCXE-binding cleft on pRB renders it resistant to E7 binding and inactivation. Such binding cleft mutants of pRB are capable of inducing a G1 arrest in the human papillomavirus 18-transformed HeLa cell line. We show here that the efficient inactivation of pRB in HeLa cells does not simply depend on the integrity of the LXCXE-binding cleft. Multiple site-directed mutants that alter conserved surfaces of the pRB pocket domain cause HeLa cells to accumulate in G1. We divide these mutants into two classes: those that can be bound by E7 and those that cannot. The E7 interacting mutants include changes in conserved residues that lie in a groove between the A and B halves of the pocket. Surprisingly, none of these mutants show a clear defect in any of the known mechanisms for pRB inactivation by E7. Analysis of mutants that are compromised for E7 binding reveals that this interaction depends on both the LXCXE-binding cleft and on a conserved group of lysines adjacent to the cleft. These basic amino acids on pRB define a discrete interaction point with E7. These residues most likely form ionic interactions with conserved acidic amino acids on E7 since a stable pRB/E7 interaction was restored when the lysine residues on pRB and the acidic residues on E7 were interchanged. PMID:12021356
Dick, Frederick A.; Dyson, Nicholas J.
2002-01-01
34
PubMed Central
The HPV-oncoprotein, E7 promotes proteasomal degradation of the tumor suppressor protein, Rb. In this study, we analyzed the regulation of E7-induced Rb proteolysis in HPV-containing Caski cervical cancer cells. We show that the Rb proteolysis is cell cycle dependent; in S phase Rb is stable while in post-mitotic early G1 phase cells and in differentiated cells, Rb is unstable. Similarly, the in vivo Rb/E7 interaction is not detected in S phase cells, but is readily detected in differentiating Caski cells. The ubiquitinating enzymes involved in Rb proteolysis have not been identified. We find that the E3 ligase MDM2 is not involved in the Rb proteolysis in Caski cells. An in vivo analysis using multiple catalytic-site mutant dominant negative E2-enzymes show that the C92A E2-25K most effectively blocks E7-induced Rb proteolysis. Taken together, these results show that E7 induces Rb proteolysis in growth-arrested cells and E2-25K is involved in the proteolysis. PMID:19906396
Oh, Kwang-Jin; Kalinina, Anna; Bagchi, Srilata
2009-01-01
35
PubMed
Papillomaviruses (PVs) are a large family of small DNA viruses infecting mammals, reptiles, and birds. PV infection induces cell proliferation that may lead to the formation of orogenital or skin tumors. PV-induced cell proliferation has been related mainly to the expression of two small oncoproteins, E6 and E7. In mammalian PVs, E6 contains two 70-residue zinc-binding repeats, whereas E7 consists of a natively unfolded N-terminal region followed by a zinc-binding domain which folds as an obligate homodimer. Here, we show that both the novel francolin bird PV Francolinus leucoscepus PV type 1 (FlPV-1) and the chaffinch bird PV Fringilla coelebs PV contain unusual E6 and E7 proteins. The avian E7 proteins contain an extended unfolded N terminus and a zinc-binding domain of reduced size, whereas the avian E6 proteins consist of a single zinc-binding domain. A comparable single-domain E6 protein may have existed in a common ancestor of mammalian and avian PVs. Mammalian E6 C-terminal domains are phylogenetically related to those of single-domain avian E6, whereas mammalian E6 N-terminal domains seem to have emerged by duplication and subsequently diverged from the original ancestral domain. In avian and mammalian cells, both FlPV-1 E6 and FlPV-1 E7 were evenly expressed in the cytoplasm and the nucleus. Finally, samples of full-length FlPV-1 E6 and the FlPV-1 E7 C-terminal zinc-binding domain were prepared for biophysical analysis. Both constructs were highly soluble and well folded, according to nuclear magnetic resonance spectroscopy measurements. PMID:19553340
Van Doorslaer, Koenraad; Sidi, Abdellahi Ould M'hamed Ould; Zanier, Katia; Rybin, Vladimir; Deryckère, François; Rector, Annabel; Burk, Robert D; Lienau, E Kurt; van Ranst, Marc; Travé, Gilles
2009-09-01
36
PubMed Central
Papillomaviruses (PVs) are a large family of small DNA viruses infecting mammals, reptiles, and birds. PV infection induces cell proliferation that may lead to the formation of orogenital or skin tumors. PV-induced cell proliferation has been related mainly to the expression of two small oncoproteins, E6 and E7. In mammalian PVs, E6 contains two 70-residue zinc-binding repeats, whereas E7 consists of a natively unfolded N-terminal region followed by a zinc-binding domain which folds as an obligate homodimer. Here, we show that both the novel francolin bird PV Francolinus leucoscepus PV type 1 (FlPV-1) and the chaffinch bird PV Fringilla coelebs PV contain unusual E6 and E7 proteins. The avian E7 proteins contain an extended unfolded N terminus and a zinc-binding domain of reduced size, whereas the avian E6 proteins consist of a single zinc-binding domain. A comparable single-domain E6 protein may have existed in a common ancestor of mammalian and avian PVs. Mammalian E6 C-terminal domains are phylogenetically related to those of single-domain avian E6, whereas mammalian E6 N-terminal domains seem to have emerged by duplication and subsequently diverged from the original ancestral domain. In avian and mammalian cells, both FlPV-1 E6 and FlPV-1 E7 were evenly expressed in the cytoplasm and the nucleus. Finally, samples of full-length FlPV-1 E6 and the FlPV-1 E7 C-terminal zinc-binding domain were prepared for biophysical analysis. Both constructs were highly soluble and well folded, according to nuclear magnetic resonance spectroscopy measurements. PMID:19553340
Van Doorslaer, Koenraad; Ould M'hamed Ould Sidi, Abdellahi; Zanier, Katia; Rybin, Vladimir; Deryckère, François; Rector, Annabel; Burk, Robert D.; Lienau, E. Kurt; van Ranst, Marc; Travé, Gilles
2009-01-01
37
PubMed
Listeria monocytogenes is a bacterium that can be genetically modified to express fusion proteins with antigens specific to certain cancer models. This technology has been harnessed to develop ADXS11-001, a vaccine that aims to elicit an immune response against human papillomavirus (HPV) oncoprotein E7.??Pre-clinical studies assessing the efficacy of recombinant Listeria vaccination targeting this same oncoprotein have consistently demonstrated successful reduction of in vivo tumor burden among animal cancer models. Several clinical trials are underway to assess the efficacy of ADXS11-001 in eliciting both immune and clinical responses against HPV-related human cervical, oropharyngeal and anal cancers. PMID:25483687
Cory, Lori; Chu, Christina
2014-11-01
38
PubMed
HPV-16 infection may play an important role in the development of non-small cell lung cancer (NSCLC) among never-smokers. Due to the critical role of angiogenesis in NSCLC development, we describe here the effect of HPV-16 oncoproteins on angiogenesis in NSCLC and the underlying mechanisms. We found that overexpression of HPV-16 E6 and E7 oncoproteins in NSCLC cells significantly promoted angiogenesis both in vitro and in vivo, and correspondingly, an enhanced expression of HIF-1? and VEGF, important pro-angiogenic factors in tumor angiogenesis. Meanwhile, overexpression of HPV-16 oncoproteins also led to HIF-1?-dependent increases in the secretion of several other pro-angiogenic factors, including IL-8. Our findings suggest that HPV-16 oncoproteins contribute to the development of NSCLC possibly by promoting HIF-1?/VEGF-mediated tumor angiogenesis. PMID:21868151
Li, Gang; He, Li; Zhang, Erying; Shi, Jingli; Zhang, Qunzhou; Le, Anh D; Zhou, Keyuan; Tang, Xudong
2011-12-01
39
PubMed
Luteolin, a flavonoid extracted from a number of plants with recognized anticancer, anti-inflammatory and anti-oxidative activities, inhibits angiogenic processes and modulates multidrug resistance. However, the efficacy and mechanisms of action of this flavonoid agent are still undergoing study. In order to elucidate whether luteolin exhibits an anticancer effect in cervical cancer cells, HeLa cells were incubated with luteolin and apoptosis was assessed by observing nuclear morphological changes, and performing Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining. Cell cycle analysis, western blotting, RT-PCR and mitochondrial membrane potential measurements were also carried out. Luteolin showed a significant dose-dependent cytotoxic effect only in human papillomavirus (HPV)-positive cervical cancer cells, when compared to its effect on HPV-negative cervical cancer C33A cells. Expression levels of human papilloma virus E6 and E7 oncogenes were suppressed, those of related factors pRb and p53 were recovered and E2F5 was increased by luteolin treatment. Furthermore, luteolin enhanced the expression of death receptors and death receptor downstream factors such as Fas/FasL, DR5/TRAIL and FADD in HeLa cells, and activated caspase cascades. In particular, luteolin enhanced the activity of caspase-3 and -8 in a dose-dependent manner. Activation of caspase-3 induced caspase-8 activity and vice versa. Luteolin also induced mitochondrial membrane potential collapse and cytochrome c release, and inhibited Bcl-2 and Bcl-xL expression. In conclusion, luteolin exerts anticarcinogenic activity through inhibition of E6 and E7 expression and cross-activation of caspase-3 and -8. Taken together, these results suggest that luteolin induces inactivation of HPV-18 oncogene expression and apoptosis by activating the intrinsic and extrinsic pathways. PMID:24789165
Ham, Sunyoung; Kim, Ki Hong; Kwon, Tae Ho; Bak, Yesol; Lee, Dong Hun; Song, Yong Seok; Park, Su-Ho; Park, Yun Sun; Kim, Man Sub; Kang, Jeong Woo; Hong, Jin Tae; Yoon, Do-Young
2014-06-01
40
Current strategies to prevent or treat human papillomavirus type 16 (HPV-16) infection are promising, but remain costly. More economical but efficient vaccines are thus needed. In this study, we evaluated the protective effects of mucosally coadministered live Lactococcus lactis strains expressing cell wall-anchored E7 Ag and a secreted form of IL-12 to treat HPV-16-induced tumors in a murine model. When
Luis G. Bermudez-Humaran; Naima G. Cortes-Perez; Francois Lefevre; Sylvie Rabot; Juan M. Alcocer-Gonzalez; Jean-Jacques Gratadoux; Cristina Rodriguez-Padilla; Reyes S. Tamez-Guerra; Gerard Corthier; Alexandra Gruss; Philippe Langella
2005-01-01
41
PubMed
Kaposi's sarcoma-associated herpesvirus (KSHV) K13/vFLIP (viral Flice-inhibitory protein) induces transcription of numerous genes through NF-?B activation, including pro-inflammatory cytokines, which contribute to the pathogenesis of Kaposi's sarcoma (KS). In this study, we report that KSHV vFLIP induces the expression of the NF-?B regulatory proteins A20, ABIN-1 and ABIN-3 (A20-binding NF-?B inhibitors) in primary human endothelial cells, and that KS spindle cells express A20 in KS tissue. In reporter assays, A20 strongly impaired vFLIP-induced NF-?B activation in 293T cells, but ABIN-1 and ABIN-3 did not. Mutational analysis established that the C-terminal domain (residues 427-790) is critical for A20 modulation of NF-?B, but the ubiquitin-editing OTU (ovarian tumor) domain is not. In functional assays, A20 inhibited vFLIP-induced expression of the chemokine IP-10, reduced vFLIP-induced cell proliferation and increased IKK1 protein levels. Thus, we demonstrate that A20 negatively regulates NF-?B activation directly induced by KSHV vFLIP. By attenuating excessive and prolonged vFLIP-induced NF-?B activation that could be harmful to KSHV-infected cells, A20 likely has an important role in the pathogenesis of KSHV-associated diseases, in which vFLIP is expressed. PMID:22525270
Sakakibara, S; Espigol-Frigole, G; Gasperini, P; Uldrick, T S; Yarchoan, R; Tosato, G
2013-03-01
42
PubMed
Kaposi's sarcoma-associated herpesvirus (KSHV) has been linked to the development of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease (MCD). We have characterized the role of KSHV-encoded viral FLICE inhibitory protein (vFLIP) K13 in the modulation of anti-IgM-induced growth arrest and apoptosis in B cells. We demonstrate that K13 protects WEHI 231, an immature B-cell line, against anti-IgM-induced growth arrest and apoptosis. The protective effect of K13 was associated with the activation of the NF-?B pathway and was deficient in a mutant K13 with three alanine substitutions at positions 58 to 60 (K13-58AAA) and a structural homolog, vFLIP E8, both of which lack NF-?B activity. K13 upregulated the expression of NF-?B subunit RelB and blocked the anti-IgM-induced decline in c-Myc and rise in p27(Kip1) that have been associated with growth arrest and apoptosis. K13 also upregulated the expression of Mcl-1, an antiapoptotic member of the Bcl2 family. Finally, K13 protected the mature B-cell line Ramos against anti-IgM-induced apoptosis through NF-?B activation. Inhibition of anti-IgM-induced apoptosis by K13 may contribute to the development of KSHV-associated lymphoproliferative disorders. PMID:23236068
Graham, Ciaren; Matta, Hittu; Yang, Yanqiang; Yi, Han; Suo, Yulan; Tolani, Bhairavi; Chaudhary, Preet M
2013-02-01
43
E-print Network
We explore some curious implications of Seiberg duality for an SU(2) four-dimensional gauge theory with eight chiral doublets. We argue that two copies of the theory can be deformed by an exactly marginal quartic superpotential so that they acquire an enhanced E7 flavor symmetry. We argue that a single copy of the theory can be used to define an E7-invariant superconformal boundary condition for a theory of 28 five-dimensional free hypermultiplets. Finally, we derive similar statements for three-dimensional gauge theories such as an SU(2) gauge theory with six chiral doublets or Nf=4 SQED.
Tudor Dimofte; Davide Gaiotto
2012-09-06
44
PubMed Central
The subset of acute myeloid leukemias (AML) with chromosomal translocations involving the MLL gene have a poor prognosis (referred to as 11q23-AML). The MLL fusion proteins that are expressed in 11q23-AML facilitate transcription of a set of HOX genes, including HOXA9 and HOXA10. Because Hox proteins are transcription factors, this suggests the possibility that Hox target genes mediate the adverse effects of MLL fusion proteins in leukemia. Identifying such Hox target genes might provide insights to the pathogenesis and treatment of 11q23-AML. In the current study we found that Mll-Ell (an MLL fusion protein) induced transcriptional activation of the FGF2 gene in a HoxA9- and HoxA10-dependent manner. FGF2 encodes fibroblast growth factor 2 (also referred to as basic fibroblast growth factor). Fgf2 influences proliferation and survival of hematopoietic stem cells and myeloid progenitor cells, and increased Fgf2-expression has been described in AMLs. We determined that expression of Mll-Ell in myeloid progenitor cells resulted in autocrine production of Fgf2 and Fgf2-dependent cytokine hypersensitivity. Therefore, our results implicated increased Fgf2 expression in progenitor proliferation and expansion in 11q23-AML. Because small molecule inhibitors of Fgf-receptors are in human clinical trials, this suggested a potential therapeutic approach to this treatment refractory leukemia. PMID:24089521
Shah, Chirag A.; Bei, Ling; Wang, Hao; Platanias, Leonidas C.; Eklund, Elizabeth A.
2013-01-01
45
PubMed
Andrographolide is a diterpenoid compound isolated from Andrographis paniculata that exhibits anticancer activity. We previously reported that andrographolide suppressed v-Src-mediated cellular transformation by promoting the degradation of Src. In the present study, we demonstrated the involvement of Hsp90 in the andrographolide-mediated inhibition of Src oncogenic activity. Using a proteomics approach, a cleavage fragment of Hsp90? was identified in andrographolide-treated cells. The concentration- and time-dependent induction of Hsp90 cleavage that accompanied the reduction in Src was validated in RK3E cells transformed with either v-Src or a human truncated c-Src variant and treated with andrographolide. In cancer cells, the induction of Hsp90 cleavage by andrographolide and its structural derivatives correlated well with decreased Src levels, the suppression of transformation, and the induction of apoptosis. Moreover, the andrographolide-induced Hsp90 cleavage, Src degradation, inhibition of transformation, and induction of apoptosis were abolished by a ROS inhibitor, N-acetyl-cysteine. Notably, Hsp90 cleavage, decreased levels of Bcr-Abl (another known Hsp90 client protein), and the induction of apoptosis were also observed in human K562 leukemia cells treated with andrographolide or its active derivatives. Together, we demonstrated a novel mechanism by which andrographolide suppressed cancer malignancy that involved inhibiting Hsp90 function and reducing the levels of Hsp90 client proteins. Our results broaden the molecular basis of andrographolide-mediated anticancer activity. PMID:24161787
Liu, Sheng-Hung; Lin, Chao-Hsiung; Liang, Fong-Ping; Chen, Pei-Fen; Kuo, Cheng-Deng; Alam, Mohd Mujahid; Maiti, Barnali; Hung, Shih-Kai; Chi, Chin-Wen; Sun, Chung-Ming; Fu, Shu-Ling
2014-01-15
46
High-risk human papillomaviruses (HPV) cause cervical cancer. The biological properties of HPV-45, the third most prevalent high-risk HPV-genotype, are unknown. We demonstrate here that the HPV-45 E7 protein transforms immortalized NIH3T3 fibroblasts, while mutations in either the conserved LXCXE sequence (C28G) or the carboxyl-terminus (?87LQQLF91) significantly abolish this activity. To address the mechanisms underlying cell transformation by HPV-45 E7, we
Dieter Morandell; Ursula Rostek; Veronique Bouvard; Beatriz Campo-Fernández; Marc Fiedler; Pidder Jansen-Dürr; Werner Zwerschke
2008-01-01
47
PubMed Central
Polo-like kinase 1 (PLK1) is highly expressed in many cancers and therefore a biomarker of transformation and potential target for the development of cancer-specific small molecule drugs. RO3280 was recently identified as a novel PLK1 inhibitor; however its therapeutic effects in leukemia treatment are still unknown. We found that the PLK1 protein was highly expressed in leukemia cell lines as well as 73.3% (11/15) of pediatric acute myeloid leukemia (AML) samples. PLK1 mRNA expression was significantly higher in AML samples compared with control samples (82.95 ± 110.28 vs. 6.36 ± 6.35; p < 0.001). Kaplan-Meier survival analysis revealed that shorter survival time correlated with high tumor PLK1 expression (p = 0.002). The 50% inhibitory concentration (IC50) of RO3280 for acute leukemia cells was between 74 and 797 nM. The IC50 of RO3280 in primary acute lymphocytic leukemia (ALL) and AML cells was between 35.49 and 110.76 nM and 52.80 and 147.50 nM, respectively. RO3280 induced apoptosis and cell cycle disorder in leukemia cells. RO3280 treatment regulated several apoptosis-associated genes. The regulation of DCC, CDKN1A, BTK, and SOCS2 was verified by western blot. These results provide insights into the potential use of RO3280 for AML therapy; however, the underlying mechanisms remain to be determined. PMID:25574601
Wang, Na-Na; Li, Zhi-Heng; Zhao, He; Tao, Yan-Fang; Xu, Li-Xiao; Lu, Jun; Cao, Lan; Du, Xiao-Juan; Sun, Li-Chao; Zhao, Wen-Li; Xiao, Pei-Fang; Fang, Fang; Su, Guang-Hao; Li, Yan-Hong; Li, Gang; Li, Yi-Ping; Xu, Yun-Yun; Zhou, Hui-Ting; Wu, Yi; Jin, Mei-Fang; Liu, Lin; Ni, Jian; Wang, Jian; Hu, Shao-Yan; Zhu, Xue-Ming; Feng, Xing; Pan, Jian
2015-01-01
48
PubMed
Cervical cancer is the second most common cancer among women worldwide and is responsible for 275,000 deaths each year. Persistent infection with high-risk human papillomavirus (HR-HPV) is an essential factor for the development of cervical cancer. Although the process is not fully understood, molecular mechanisms caused by HPV infection are necessary for its development and reveal a large number of potential biomarkers for diagnosis and prognosis. These molecules are host genes and/or proteins, and cellular microRNAs involved in cell cycle regulation that result from disturbed expression of HR-HPV E5, E6 and E7 oncoproteins. One of the current challenges in medicine is to discover potent biomarkers that can correctly diagnose cervical premalignant lesions and standardize clinical management. Currently, studies are showing that some of these molecules are potential biomarkers of cervical carcinogenesis, and it is possible to carry out a more accurate diagnosis and provide more appropriate follow-up treatment for women with cervical dysplasia. In this paper, we review recent research studies on cell cycle molecules deregulated by HPV infections, as well as their potential use for cervical cancer screening. PMID:24388872
de Freitas, Antonio Carlos; Coimbra, Eliane Campos; Leitão, Maria da Conceição Gomes
2014-04-01
49
PubMed
The potential of Herpesvirus saimiri (HVS) subgroups A, B and C and Herpesvirus ateles (HVA) to transform primary T cells to permanent growth in vitro is restricted by the primate host species and by viral variability represented by distinct viral oncoproteins. We now addressed the relation between the transforming potential of the different viruses and the signaling pathways activated by transiently expressed oncoproteins. Marmoset lymphocytes were transformed by all HVS subgroups as well as HVA, while transformation of human cells was restricted to HVS-C and, unexpectedly, HVA. NF-?B and Src-family kinase (SFK) activity was required for survival of all transformed lymphocytes. Accordingly, NF-?B was induced by oncoproteins of all viruses. In contrast, SFK-related signaling was detectable only for oncoproteins of HVS-C and HVA. Thus, the restricted transformation of human lymphocytes likely correlates with the specific SFK targeting by these oncoproteins. These results will enable further studies into novel SFK effector mechanisms relevant for T-cell proliferation. PMID:22374337
Katsch, Kristin; de Jong, Sarah Jill; Schmidt, Monika; Müller-Fleckenstein, Ingrid; Fleckenstein, Bernhard; Albrecht, Jens-Christian; Biesinger, Brigitte
2012-05-01
50
The adenoviral oncoprotein E1A induces progression through the cell cycle by binding to the products of the p300\\/CBP and retinoblastoma gene families. A new cellular p300\\/CBP-associated factor (P\\/CAF) having intrinsic histone acetylase activity has been identified that competes with E1A. Exogenous expression of P\\/CAF in HeLa cells inhibits cell-cycle progression and counteracts the mitogenic activity of E1A. E1A disturbs the
Xiang-Jiao Yang; Vasily V. Ogryzko; Jun-Ichi Nishikawa; Bruce H. Howard; Yoshihiro Nakatani
1996-01-01
51
Oncogenic activation of ERG resulting from gene fusion is present in over half of all patients with prostate cancer in Western countries. Although the underlying genetic mechanisms have been extensively studied, evaluation of the ERG oncoprotein—the translational product of ERG gene fusions—has just begun. The robust correlation between ERG oncoprotein detection and gene fusion status enables rapid characterization of this
Philip Rosen; Isabell A. Sesterhenn; Stephen A. Brassell; David G. McLeod; Shiv Srivastava; Albert Dobi
2012-01-01
52
PubMed
Although current polyvalent vaccines can prevent development of cervical cancer, they cannot be used to treat patients who already have the disease. Adenovirus expressing calreticulin-E7 (Ad-CRT-E7) has shown promising results in the cervical cancer murine model. We also demonstrated that immunization with Lactococcus lactis encoding HPV-16 E7 (Ll-E7) anchored to its surface induces significant HPV-16 E7-specific immune response. Here, we assessed the combination of both approaches in the treatment of a cervical cancer animal model. Intranasal preimmunization of Ll-E7, followed by a single Ad-CRT/E7 application, induced ?80% of tumor suppression in comparison with controls. Mice treated with a combination of Ll-E7 and Ad-CRT/E7 resulted in a 70% survival rate 300 days post-treatment, whereas 100% of the mice in the control groups died by 50 days. Significant CD8+ cytotoxic T-lymphocytes infiltration was detected in the tumors of mice treated with Ll-E7+Ad-CRT/E7. Tumors with regression showed a greater number of positive cells for in situ TUNEL staining than controls. Our results suggest that preimmunization with Ll-E7 enhances the Ad-CRT/E7-mediated antitumor effect. This treatment provides an enormous advantage over repeated applications of Ad-CRT/E7 by maintaining the effectiveness of the three-dose application of Ad-CRT/E7, but avoiding the high systemic toxicities associated with such repeat treatments. PMID:25216057
Rangel-Colmenero, Blanca R; Gomez-Gutierrez, Jorge G; Villatoro-Hernández, Julio; Zavala-Flores, Laura M; Quistián-Martínez, Deyanira; Rojas-Martínez, Augusto; Arce-Mendoza, Alma Y; Guzmán-López, Santos; Montes-de-Oca-Luna, Roberto; Saucedo-Cárdenas, Odila
2014-11-01
53
PubMed
E7 is an accessory protein that is not encoded by all papillomaviruses. The E7 amino terminus contains two regions of similarity to conserved regions 1 and 2 of the adenovirus E1A protein, which are also conserved in the simian vacuolating virus 40 large tumor antigen. The E7 carboxyl terminus consists of a zinc-binding motif, which is related to similar motifs in E6 proteins. E7 proteins play a central role in the human papillomavirus life cycle, reprogramming the cellular environment to be conducive to viral replication. E7 proteins encoded by the cancer-associated alpha human papillomaviruses have potent transforming activities, which together with E6, are necessary but not sufficient to render their host squamous epithelial cell tumorigenic. This article strives to provide a comprehensive summary of the published research studies on human papillomavirus E7 proteins. PMID:23731972
Roman, Ann; Munger, Karl
2013-10-01
54
PubMed Central
Summary MLL fusion proteins in leukemia induce aberrant transcriptional elongation and associated chromatin perturbations, however the upstream signaling pathways and activators that recruit or retain MLL oncoproteins at initiated promoters are unknown. Through functional and comparative genomic studies, we identified an essential role for NF-?B signaling in MLL leukemia. Suppression of NF-?B led to robust anti-leukemia effects that phenocopied loss of functional MLL oncoprotein or associated epigenetic cofactors. The NF-?B subunit RELA occupies promoter regions of crucial MLL target genes and sustains the MLL-dependent leukemia stem cell program. IKK/NF-?B signaling is required for wild-type and fusion MLL protein retention and maintenance of associated histone modifications providing a molecular rationale for enhanced efficacy in therapeutic targeting of this pathway in MLL leukemias. PMID:24054986
Kuo, Hsu-Ping; Wang, Zhong; Lee, Dung-Fang; Iwasaki, Masayuki; Duque-Afonso, Jesus; Wong, Stephen H.K.; Lin, Chiou-Hong; Figueroa, Maria E.; Su, Jie; Lemischka, Ihor R.; Cleary, Michael L.
2013-01-01
55
The high-risk human papillomaviruses (HPVs) are associated with carcinomas of the cervix and other genital tumors. Previous studies have identified two viral oncoproteins, E6 and E7, which are expressed in the majority of HPV-associated carcinomas. The ability of high-risk HPV E6 protein to immortalize human mam- mary epithelial cells (MECs) has provided a single-gene model to study the mechanisms of
QINGSHEN GAO; SEETHA SRINIVASAN; SARAH N. BOYER; DAVID E. WAZER; VIMLA BAND
1999-01-01
56
PubMed Central
Infections with high-risk human papillomaviruses (HPVs) are causally involved in the development of anogenital cancer. HPVs apparently evade the innate immune response of their host cells by dysregulating immunomodulatory factors such as cytokines and chemokines, thereby creating a microenvironment that favors malignancy. One central key player in the immune surveillance interactome is interleukin-1 beta (IL-1?) which not only mediates inflammation, but also links innate and adaptive immunity. Because of its pleiotropic physiological effects, IL-1? production is tightly controlled on transcriptional, post-translational and secretory levels. Here, we describe a novel mechanism how the high-risk HPV16 E6 oncoprotein abrogates IL-1? processing and secretion in a NALP3 inflammasome-independent manner. We analyzed IL-1? regulation in immortalized keratinocytes that harbor the HPV16 E6 and/or E7 oncogenes as well as HPV-positive cervical tumor cells. While in primary and in E7-immortalized human keratinocytes the secretion of IL-1? was highly inducible upon inflammasome activation, E6-positive cells did not respond. Western blot analyses revealed a strong reduction of basal intracellular levels of pro-IL-1? that was independent of dysregulation of the NALP3 inflammasome, autophagy or lysosomal activity. Instead, we demonstrate that pro-IL-1? is degraded in a proteasome-dependent manner in E6-positive cells which is mediated via the ubiquitin ligase E6-AP and p53. Conversely, in E6- and E6/E7-immortalized cells pro-IL-1? levels were restored by siRNA knock-down of E6-AP and simultaneous recovery of functional p53. In the context of HPV-induced carcinogenesis, these data suggest a novel post-translational mechanism of pro-IL-1? regulation which ultimately inhibits the secretion of IL-1? in virus-infected keratinocytes. The clinical relevance of our results was further confirmed in HPV-positive tissue samples, where a gradual decrease of IL-1? towards cervical cancer could be discerned. Hence, attenuation of IL-1? by the HPV16 E6 oncoprotein in immortalized cells is apparently a crucial step in viral immune evasion and initiation of malignancy. PMID:23935506
Niebler, Martina; Qian, Xu; Höfler, Daniela; Kogosov, Vlada; Kaewprag, Jittranan; Kaufmann, Andreas M.; Ly, Regina; Böhmer, Gerd; Zawatzky, Rainer; Rösl, Frank; Rincon-Orozco, Bladimiro
2013-01-01
57
Experimentally-induced mutations in the C3HC4 RING finger domain of the Bmi-1 oncoprotein block its ability to induce lymphomas in mice. In this report, the role of the Bmi-1 RING finger in mediating protein-protein interactions is examined using the yeast two-hybrid system. Bmi-1 interacts directly with the RING finger protein dinG\\/RING1B. Heterodimerization of the two proteins requires the intact RING finger
Charles S Hemenway; Benjamin W Halligan; Laura S Levy
1998-01-01
58
SciTech Connect
Epidemiological and experimental studies have shown that high-risk human papillomaviruses (HPVs) are the causative agents of cervical cancer worldwide, and that HPV-16 is associated with more than half of these cases. In addition to the well-characterized E6 and E7 oncoproteins of HPV-16, recent evidence increasingly has implicated the HPV-16 E5 protein (16E5) as an important mediator of oncogenic transformation. Since 16E5 has no known intrinsic enzymatic activity, its effects on infected cells are most likely mediated by interactions with various cellular proteins and/or its documented association with lipid rafts. In the present study, we describe a new cellular target that binds to 16E5 in COS cells and in stable human ectocervical cell lines. This target is karyopherin {beta}3, a member of the nuclear import receptor family with critical roles in the nuclear import of ribosomal proteins and in the secretory pathway.
Krawczyk, Ewa [Department of Pathology, Georgetown University Medical School, 3900 Reservoir Road NW, Washington, DC 20057 (United States); Hanover, John A. [Laboratory of Cell Biochemistry and Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892 (United States); Schlegel, Richard [Department of Pathology, Georgetown University Medical School, 3900 Reservoir Road NW, Washington, DC 20057 (United States); Suprynowicz, Frank A. [Department of Pathology, Georgetown University Medical School, 3900 Reservoir Road NW, Washington, DC 20057 (United States)], E-mail: [email protected]
2008-07-11
59
PubMed
High-risk human papillomaviruses (HPV) are the main etiologic factor for the development of cervical cancer. Infections by these viruses have been detected in virtually all cervical cancers. C-33A is one of the rare cervical cancer derived cell lines considered as HPV-negative. Employing monoclonal antibodies raised against a conformational epitope of the HPV-16 E7 oncoprotein, we present evidence suggesting that E7-positive cells can be sporadically and transiently detected in C-33A cell cultures. Immunoblotting with affinity-purified rabbit polyclonal anti-HPV 16 E7 antisera and q-RT-PCR analysis suggest that these cells do probably not express HPV-16 E7. Moreover, we show that the HPV E7 protein level differs considerably between individual cells in cultures of several established cervical cancer cell lines. Our data suggest that expression of the E7 protein is variable in established cervical cancer cell lines including C-33A cells. PMID:25326774
Kaiser, Andreas; Jenewein, Brigitte; Pircher, Haymo; Rostek, Ursula; Jansen-Dürr, Pidder; Zwerschke, Werner
2014-10-19
60
Saimiriine herpesvirus 2 (Herpesvirus saimiri) is capable of inducing lethal T-cell lymphoproliferative diseases in primates and of immortalizing human T lymphocytes in vitro. Two viral oncoproteins, Tip and StpC, are essential for T-cell transformation by Herpesvirus saimiri strains of the subgroup C, which exhibits a higher transformation potential than other subgroups of this virus. Despite the importance of these proteins,
Joseph J. Merlo; Alexander Y. Tsygankov
2001-01-01
61
PubMed
Lymphocytes establish dynamic cell-cell interactions with the cells they scan. Previous studies show that upon cell contact, various membrane-associated proteins, such as Ras-family proteins, transfer from B to T and NK lymphocytes. Mutations in RAS genes that encode constitutively active, GTP-bound, oncoproteins are rather common in human cancers; for instance, melanoma. Cancer immunoediting has been postulated to contribute to the elimination of malignant melanoma. Thus, we asked whether Ras oncoproteins can transfer from melanoma to T cells, including tumor-infiltrating lymphocytes (TILs), and subsequently induce functional effects in the adopting T cells. To explore this issue, we genetically engineered an HLA-A2(+) melanoma cell line, MEL526, to express GFP or GFP-tagged H-Ras mutants stably. In this study, we show by an in vitro coculture system that GFP-tagged H-Ras, but not GFP, transfers from MEL526 to T cells and localizes to the inner aspect of their plasma membrane. This cell-contact-dependent process was increased by TCR stimulation and did not require strict Ag specificity. Importantly, we found a positive correlation between the levels of the acquired constitutively active H-RasG12V and ERK1/2 phosphorylation within the adopting TILs. We also show a significant increase in IFN-? production and cytotoxic activity in TILs that acquired H-RasG12V compared to TILs that acquired a different H-Ras mutant. In conclusion, our findings demonstrate a hitherto unknown phenomenon of intercellular transfer of Ras oncoproteins from melanoma to TILs that consequently augments their effector functions. PMID:23028055
Vernitsky, Helly; Rechavi, Oded; Rainy, Nir; Besser, Michal J; Nagar, Meital; Schachter, Jacob; Lerenthal, Yaniv; Ehrlich, Marcelo; Kloog, Yoel; Goldstein, Itamar
2012-11-01
62
PubMed
Super-enhancers are clusters of gene-regulatory sites bound by multiple transcription factors that govern cell transcription, development, phenotype, and oncogenesis. By examining Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (LCLs), we identified four EBV oncoproteins and five EBV-activated NF-?B subunits co-occupying ?1,800 enhancer sites. Of these, 187 had markedly higher and broader histone H3K27ac signals, characteristic of super-enhancers, and were designated "EBV super-enhancers." EBV super-enhancer-associated genes included the MYC and BCL2 oncogenes, which enable LCL proliferation and survival. EBV super-enhancers were enriched for B cell transcription factor motifs and had high co-occupancy of STAT5 and NFAT transcription factors (TFs). EBV super-enhancer-associated genes were more highly expressed than other LCL genes. Disrupting EBV super-enhancers by the bromodomain inhibitor JQ1 or conditionally inactivating an EBV oncoprotein or NF-?B decreased MYC or BCL2 expression and arrested LCL growth. These findings provide insight into mechanisms of EBV-induced lymphoproliferation and identify potential therapeutic interventions. PMID:25639793
Zhou, Hufeng; Schmidt, Stefanie C S; Jiang, Sizun; Willox, Bradford; Bernhardt, Katharina; Liang, Jun; Johannsen, Eric C; Kharchenko, Peter; Gewurz, Benjamin E; Kieff, Elliott; Zhao, Bo
2015-02-11
63
PubMed Central
NUT midline carcinoma (NMC) is an aggressive subtype of squamous cell carcinoma that typically harbors BRD4/3-NUT fusion oncoproteins that block differentiation and maintain tumor growth. In 20% of cases NUT is fused to uncharacterized non-BRD gene(s). We established a new patient-derived NMC cell line (1221) and demonstrated that it harbors a novel NSD3-NUT fusion oncogene. We find that NSD3-NUT is both necessary and sufficient for the blockade of differentiation and maintenance of proliferation in NMC cells. NSD3-NUT binds to BRD4, and BRD bromodomain inhibitors induce differentiation and arrest proliferation of 1221 cells. We find further that NSD3 is required for the blockade of differentiation in BRD4-NUT-expressing NMCs. These findings identify NSD3 as a novel critical oncogenic component and potential therapeutic target in NMC. PMID:24875858
French, Christopher A.; Rahman, Shaila; Walsh, Erica M.; Kühnle, Simone; Grayson, Adlai R.; Lemieux, Madeleine E.; Grunfeld, Noam; Rubin, Brian P.; Antonescu, Cristina R.; Zhang, Songlin; Venkatramani, Rajkumar; Cin, Paola Dal; Howley, Peter M.
2014-01-01
64
Sequence-specific single-stranded DNA-binding protein 2 (SSBP2) is a candidate tumor suppressor for human acute myelogenous leukemia (AML). Inducible expression of SSBP2 causes growth arrest and partial differentiation in AML cells. Here, we report that the adenoviral oncoprotein E1B55K directly binds to endogenous SSBP2 protein and sequesters it into juxtanuclear bodies in adenovirally transformed human embryonic kidney (HEK) 293 cells. Similarly,
H B Fleisig; N I Orazio; H Liang; A F Tyler; H P Adams; M D Weitzman; L Nagarajan
2007-01-01
65
PubMed
Expression of developmental genes Twist1 and Twist2 is reactivated in many human tumors. Among their oncogenic activities, induction of epithelial to mesenchymal transition is believed to increase cell motility and invasiveness and may be related to acquisition of cancer stem cell phenotype. In addition, Twist proteins promote malignant conversion by overriding two oncogene-induced failsafe programs: senescence and apoptosis. Reactive oxygen species (ROS) are also important mediators of apoptosis, senescence and motility and are tightly linked to disease, notably to cancer. We report here that Twist factors and ROS are functionally linked. In wild type cells both Twist1 and Twist2 exhibit antioxidant properties. We show that Twist-driven modulation of oncogene-induced apoptosis is linked to its effects on oxidative stress. Finally, we identify several targets that mediate Twist antioxidant activity. These findings unveil a new function of Twist factors that could be important in explaining their pleiotropic role during carcinogenesis. PMID:23967308
Floc'h, Nicolas; Kolodziejski, Jakub; Akkari, Leila; Simonin, Yannick; Ansieau, Stéphane; Puisieux, Alain; Hibner, Urszula; Lassus, Patrice
2013-01-01
66
PubMed Central
Expression of developmental genes Twist1 and Twist2 is reactivated in many human tumors. Among their oncogenic activities, induction of epithelial to mesenchymal transition is believed to increase cell motility and invasiveness and may be related to acquisition of cancer stem cell phenotype. In addition, Twist proteins promote malignant conversion by overriding two oncogene-induced failsafe programs: senescence and apoptosis. Reactive oxygen species (ROS) are also important mediators of apoptosis, senescence and motility and are tightly linked to disease, notably to cancer. We report here that Twist factors and ROS are functionally linked. In wild type cells both Twist1 and Twist2 exhibit antioxidant properties. We show that Twist-driven modulation of oncogene-induced apoptosis is linked to its effects on oxidative stress. Finally, we identify several targets that mediate Twist antioxidant activity. These findings unveil a new function of Twist factors that could be important in explaining their pleiotropic role during carcinogenesis. PMID:23967308
Akkari, Leila; Simonin, Yannick; Ansieau, Stéphane; Puisieux, Alain; Hibner, Urszula; Lassus, Patrice
2013-01-01
67
PubMed Central
The human papillomavirus 18 (HPV18) E6 and E7 proteins are considered to be primarily responsive for the transforming activity of the virus. In order to analyse the molecular mechanisms resulting in viral oncoprotein expression, it is necessary to identify the factors involved in the transcriptional regulation of the E6/E7 genes. Here we define by gel retardation experiments a sequence aberrant Sp1 binding site present in the promoter proximal part of the viral transcriptional control region (Upstream Regulatory Region, URR). Functional analyses employing transient reporter assays reveal that this Sp1 element is required for an efficient stimulation of the HPV18 E6/E7-promoter. Mutation of the Sp1 element in the natural context of the HPV18 URR leads to a strong decrease in the activity of the E6/E7-promoter in several cell lines. The magnitude of reduction varies between different cell types and is higher in cell lines of epithelial origin when compared with nonepithelial cells. Cotransfection assays using Sp1 expression vector systems further define the promoter proximal HPV18 Sp1 binding motif as a functional Sp1 element in vivo and show that its integrity is essential for the stimulation of the E6/E7-promoter by augmented levels of Sp1. These results indicate, that the cellular transcription factor Sp1 plays an important role for the stimulation of the E6/E7-promoter by the viral URR and represents a major determinant for the expression of HPV18 transforming genes E6 and E7. Images PMID:1336181
Hoppe-Seyler, F; Butz, K
1992-01-01
68
PubMed
Herpesvirus saimiri (HVS), a member of the gamma-herpesvirus family, encodes an oncoprotein called Saimiri Transforming Protein (STP) which is required for lymphoma induction in non-human primates. However, a detailed mechanism of STP-A11-induced oncogenesis has not been revealed yet. We first report that STP-A11 oncoprotein interacts with TNF-alpha receptor-associated factor (TRAF) 6 in vivo and in vitro. Mutagenesis analysis of the TRAF6-binding motif (10)PQENDE(15) in STP-A11 reveals that Glu (E)(12) residue is critical for binding to TRAF6 and NF-kappaB activation. Interestingly, co-expression of E12A mutant, lack of TRAF6 binding, with cellular Src (Src) results in decreased transcriptional activity of Stat3 and AP-1, a novel target of STP-A11 compared to that of wild type. Furthermore, the presence of STP-A11 enhances the association of TRAF6 with Src and induces the translocation of both TRAF6 and Src to a nonionic detergent-insoluble fraction. Taken together, these studies suggest that STP-A11 oncoprotein up-regulates both NF-kappaB and AP-1 transcription activity through TRAF6, which would ultimately contribute cellular transformation. PMID:17334229
Jeong, Sunam; Cho, Il-Rae; An, Won Gun; Jhun, Byung Hak; Lee, BokSoo; Park, Keerang; Chung, Young-Hwa
2007-02-28
69
PubMed
HPV-16E7 is a major transforming protein, which has been implicated in the development of cervical cancer. The stability of E7 is thus important to ensure its fully functional status. Using the yeast two-hybrid system, we found that USP11 (ubiquitin-specific protease 11), a member of a protein family that cleaves polyubiquitin chains and/or ubiquitin precursors, interacts and forms a specific complex with HPV-16E7. Our results indicate that the USP11 can greatly increase the steady state level of HPV-16E7 by reducing ubiquitination and attenuating E7 degradation. In contrast, a catalytically inactive mutant of USP11 abolished the deubiquitinating ability and returned E7 to a normal rate of degradation. Moreover, USP11 not only protected E7 from ubiquitination but also influenced E7 function as a modulator of cell growth status. These results suggest that USP11 plays an important role in regulating the levels of E7 protein and subsequently affects the biological function of E7 as well as its contribution to cell transformation by HPV-16E7. PMID:18408009
Lin, Ching-Hui; Chang, Hung-Shu; Yu, Winston C Y
2008-06-01
70
PubMed Central
Serum response factor (SRF) acts as a multifunctional transcription factor regulated by mutually exclusive interactions with ternary complex factors (TCFs) or myocardin-related transcription factors (MRTFs). Binding of Rho- and actin-regulated MRTF:SRF complexes to target gene promoters requires an SRF-binding site only, whereas MAPK-regulated TCF:SRF complexes in addition rely on flanking sequences present in the serum response element (SRE). Here, we report on the activation of an SRE luciferase reporter by Tip, the viral oncoprotein essentially contributing to human T-cell transformation by Herpesvirus saimiri. SRE activation in Tip-expressing Jurkat T cells could not be attributed to triggering of the MAPK pathway. Therefore, we further analyzed the contribution of MRTF complexes. Indeed, Tip also activated a reporter construct responsive to MRTF:SRF. Activation of this reporter was abrogated by overexpression of a dominant negative mutant of the MRTF-family member MAL. Moreover, enrichment of monomeric actin suppressed the Tip-induced reporter activity. Further upstream, the Rho-family GTPase Rac, was found to be required for MRTF:SRF reporter activation by Tip. Initiation of this pathway was strictly dependent on Tip's ability to interact with Lck and on the activity of this Src-family kinase. Independent of Tip, T-cell stimulation orchestrates Src-family kinase, MAPK and actin pathways to induce SRF. These findings establish actin-regulated transcription in human T cells and suggest its role in viral oncogenesis. PMID:22385615
2012-01-01
71
Human T cells are transformed to antigen-independent permanent growth in vitro upon infection with herpesvirus saimiri subgroup C strains. The viral oncoproteins required for this process, StpC and Tip, could be replaced by Tio, the oncoprotein of herpesvirus ateles. Here we demonstrate that proliferation of lympho- cytes transformed with Tio-recombinant herpesvirus saimiri required the activity of Src family kinases. Src
Jens-Christian Albrecht; Ingrid Muller-Fleckenstein; Monika Schmidt; Bernhard Fleckenstein; Brigitte Biesinger
2005-01-01
72
PubMed
Epidermal keratinocytes and hair follicle (HF) stem cells (SCs) expressing oncogenes are competent at developing squamous cell carcinomas (SCCs) in epidermis and HFs, respectively. To determine whether bulge and hair germ (HG) SCs from HF contribute to SCC generation at distant epidermis, the most frequent epidermal region where these lesions arise in human skin, we used a skin cancer mouse model expressing E6 and E7 oncoproteins from Human papillomavirus (HPV) 16 in SCs and basal keratinocytes. This previously described mouse model recapitulates the human skin papillomavirus-induced SCC pathology. We show that E6 and E7 expression promote the expansion of keratin 15 (K15)-expressing cells. These K15(+) aberrant cells exhibit some HGSC markers and diminished expression of Tcf3 and Sox9 hair SC specification genes, which are accumulated in HFs and mislocalized to interfollicular epidermis. Leucine-rich G-protein-coupled receptor 5 (Lgr5)-expressing SCs, localized in the bulge and HG, are the origin of the expanded K15(+) cell population. A large subset of the Lgr5(+) SC progeny, expressing K15 and P-cadherin, is aberrantly mobilized to the upper region of HFs and the epidermis, and accumulates at E6/E7-induced pre-neoplastic lesions and epidermal tumors. These findings indicate that aberrant accumulation of altered SCs in HFs and their subsequent migration to the epidermis contribute to HPV-induced tumor development. PMID:22945646
da Silva-Diz, V; Solé-Sánchez, S; Valdés-Gutiérrez, A; Urpí, M; Riba-Artés, D; Penin, R M; Pascual, G; González-Suárez, E; Casanovas, O; Viñals, F; Paramio, J M; Batlle, E; Muñoz, P
2013-08-01
73
PubMed Central
Oncoprotein 18 (Op18, also termed p19, p18, prosolin or stathmin) is a cytosolic protein of previously unknown function. Phosphorylation of Op18 is cell cycle regulated by cyclin-dependent kinases (CDKs), and expression of a 'CDK target site-deficient mutant' results in a phenotype indicative of a role for Op18 during mitosis. This phenotype is compatible with the idea that Op18 is a phosphorylation-responsive regulator of microtubule (MT) dynamics. Therefore, in this study, we analyzed MTs in cells induced to express either wild-type or mutated Op18. The results showed that wild-type Op18 and a CDK target site mutant both efficiently elicited rapid depolymerization of MTs. This result contrasts with clear-cut differences in their cell cycle phenotypes. Morphological analysis of MTs explained this apparent discrepancy: while interphase MTs were depolymerized in cells expressing either Op18 derivative, apparently normal mitotic spindles were formed only in cells overexpressing wild-type Op18. This result correlates with our finding that only mutated Op18 causes a block during mitosis. Hence, we conclude that Op18 decreases MT stability and that this activity of Op18 is subject to cell cycle regulation by CDKs. Images PMID:8895574
1996-01-01
74
PubMed
The human T-cell lymphotropic virus type-I (HTLV-I) is the etiologic agent of adult T-cell leukemia/lymphoma (ATL) and of tropical spastic paraparesis/HTLV-I-associated myelopathy. Constitutive NF-?B activation by the viral oncoprotein Tax plays a crucial role in the induction and maintenance of cellular proliferation, transformation, and inhibition of apoptosis. In an attempt to provide a general view of the molecular mechanisms of constitutive Tax-induced NF-?B activation, we summarize in this review the recent body of literature that supports a major role for Tax posttranslational modifications, chiefly ubiquitination, and SUMOylation, in the NF-?B activity of Tax. These modifications indeed participate in the control of Tax subcellular localization and modulate its protein-protein interaction potential. Tax posttranslational modifications, which highlight the ability of HTLV-I to optimize its limited viral genome size, might represent an attractive target for the design of new therapies for ATL. PMID:22429853
Kfoury, Youmna; Nasr, Rihab; Journo, Chloé; Mahieux, Renaud; Pique, Claudine; Bazarbachi, Ali
2012-01-01
75
We discuss the construction of gaugings in recent models of E7 extended geometries, focusing on the two inequivalent S L (8 ) truncations of the theory. In these sectors the conditions for the generation of gaugings in the 36 , 36' , 420 and 420' representations of E7 (7 ) can be compactly expressed in terms of objects which are in the fundamental representation of S L (8 ), making the search of solutions simpler. We present a no-go theorem showing that neither of these truncations lead to the new S O (8 ) dyonic gaugings, at least if the so-called section conditions are implemented. We also show that these truncations can be used to obtain the generalized twist of the seven-sphere, leading to the electric S O (8 ) gaugings.
Baron, Walter H.
2015-01-01
76
PubMed Central
The capacity of breast cancer cells to form mammospheres in non-adherent serum-free culture is used as a functional characteristic of the self-renewing stem-like cell population. The present studies demonstrate that silencing expression of the MUC1-C oncoprotein inhibits growth of luminal MCF-7 and HER2-overexpressing SKBR3 breast cancer cells as mammospheres. We also show that triple-negative MDA-MB-468 breast cancer cells are dependent on MUC1-C for growth as mammospheres and tumor xenografts. Similar results were obtained when MUC1-C function was inhibited by expression of a MUC1-C(CQC?AQA) mutant. Moreover, treatment with the MUC1-C inhibitor GO-203, a cell penetrating peptide that binds to the MUC1-C cytoplasmic domain and blocks MUC1-C function, confirmed the importance of this target for self-renewal. The mechanistic basis for these findings is supported by the demonstration that MUC1-C activates NF-?B, occupies the IL-8 promoter with NF-?B, and induces IL-8 transcription. MUC1-C also induces NF-?B-dependent expression of the IL-8 receptor, CXCR1. In concert with these results, targeting MUC1-C with GO-203 suppresses IL-8/CXCR1 expression and disrupts the formation of established mammospheres. Our findings indicate that MUC1-C contributes to the self-renewal of breast cancer cells by activating the NF-?B?IL-8/CXCR1 pathway and that targeting MUC1-C represents a potential approach for the treatment of this population. PMID:24770886
Jin, Caining; Kufe, Donald
2014-01-01
77
PubMed Central
Human Papillomavirus (HPV) 16 E7 protein promotes the transformation of HPV infected epithelium to malignancy. Here, we use a murine model in which the E7 protein of HPV16 is expressed as a transgene in epithelium to show that mast cells are recruited to the basal layer of E7-expressing epithelium, and that this recruitment is dependent on the epithelial hyperproliferation induced by E7 by inactivating Rb dependent cell cycle regulation. E7 induced epithelial hyperplasia is associated with increased epidermal secretion of CCL2 and CCL5 chemokines, which attract mast cells to the skin. Mast cells in E7 transgenic skin, in contrast to those in non-transgenic skin, exhibit degranulation. Notably, we found that resident mast cells in E7 transgenic skin cause local immune suppression as evidenced by tolerance of E7 transgenic skin grafts when mast cells are present compared to the rejection of mast cell-deficient E7 grafts in otherwise competent hosts. Thus, our findings suggest that mast cells, recruited towards CCL2 and CCL5 expressed by epithelium induced to proliferate by E7, may contribute to an immunosuppressive environment that enables the persistence of HPV E7 protein induced pre-cancerous lesions. PMID:25340820
Bergot, Anne-Sophie; Ford, Neill; Leggatt, Graham R.
2014-01-01
78
PubMed
Herpesvirus saimiri (HVS), a member of the gamma-herpesvirus family, encodes an oncoprotein called Saimiri Transforming Protein (STP) which is required for lymphoma induction in non-human primates. Previous study has shown that STP-C, an oncoprotein of HVS, activates NF-kappaB signaling pathway. However, the detailed mechanism of STP-C-mediated NF-kappaB activation has not been reported yet. We first report that STP-C interacts with TRAF6 protein in vivo and in vitro and further investigation shows that Glu(12) residue of STP-C is critical for binding to TRAF6. Introduction of ubiquitin together with STP-C augments NF-kappaB activity compared to that of STP-C expression alone. STP-C expression further induces ubiquitination of endogenous TRAF6. In addition, either a deubiquitination enzyme, CYLD or a dominant negative E2-conjugation enzyme reduced NF-kappaB activity in spite of the presence of STP-C, supporting that the interaction between STP-C and TRAF6 induces ubiquitination of TRAF6. NF-kappaB activation by STP-C through the ubiquitinated TRAF6 causes the increased production of IL-8, an inflammatory chemokine and the enhanced expression of costimulatory molecule ICAM, which might ultimately contribute cellular transformation by the exposure of HVS-infected cells with inflammatory microenvironment and chronic activation. PMID:17562285
Chung, Young-Hwa; Jhun, Byung Hak; Ryu, Su-Chak; Kim, Heui-Soo; Kim, Cheol-Min; Kim, Bong-Seok; Kim, Young-Ok; Lee, Sang Jun
2007-05-31
79
E-print Network
KTS 1 1 Artificial transmembrane oncoproteins smaller than the2 bovine papillomavirus E5 protein; bovine papillomavirus21 Word count: Abtract = 190; Text = 8,63722 * Corresponding author: Tel: 203.asm.orgDownloadedfrom #12;KTS 2 ABSTRACT24 The bovine papillomavirus E5 protein (BPV E5) is a 44-amino acid homodimeric25
Gerstein, Mark
80
ERIC Educational Resources Information Center
Terms to be familiar with before you start to solve the test: human papilloma virus; cervical cancer; oncoproteins; malignant transformation; retinoblastoma protein; cell cycle; quiescent and cycling cells; cyclin/cyclin-dependent kinase (Cdk) complexes; E2F; S-phase genes; enhancer element; proto-oncogenes; tumor suppressor genes; radioactive…
Szeberenyi, Jozsef
2009-01-01
81
The distribution of hepatitis C virus (HCV) genotypes among Egyptian patients positive for anti-HCV was determined and their influence, when combined with neu-oncoprotein overexpression, on the development of hepatocellular carcinoma (HCC) was examined. The study groups included asymptomatic carriers (ASC) and patients with chronic active hepatitis (CAH) and HCC. HCV genomes were detected in the sera of 27 ASC, 29
ABDEL-RAHMAN N. ZEKRI; ABEER A. BAHNASSY; SABRY M. SHAARAWY; A. MANSOURk; MOHAMED A. MADUAR; HUSSEIN M. KHALED; OMER EL-AHMADIk
82
E-print Network
NFKB1 Is a Direct Target of the TAL1 Oncoprotein in Human T Leukemia Cells Pei-Yun Chang, 1 Kyle Abstract We recently showed that a subset of human T acute lymphoblastic leukemia (T-ALL) cell lines in CEM T leukemia cells, basal NFKB1 expression is increased, and the levels of p65:cRel complex
Miyamoto, Shigeki
83
PubMed
Overexpression of the erythroblast transformation-specific-related gene (ERG) oncoprotein due to transmembrane protease, serine 2 (TMPRSS2)-ERG fusion, the most prevalent genomic alteration in prostate cancer (CaP), is more frequently observed among Caucasian patients compared to patients of African or Asian descent. To the best of our knowledge, this is the first study to investigate the prevalence of ERG alterations in a multiethnic cohort of CaP patients. A total of 191 formalin-fixed paraffin-embedded sections of transrectal ultrasound-guided prostate biopsy specimens, collected from 120 patients treated at the Sime Darby Medical Centre, Subang Jaya, Malaysia, were analyzed for ERG protein expression by immunohistochemistry using the anti-ERG monoclonal antibody 9FY as a surrogate for the detection of ERG fusion events. The overall frequency of ERG protein expression in the population evaluated in this study was 39.2%. Although seemingly similar to rates reported in other Asian communities, the expression of ERG was distinct amongst different ethnic groups (P=0.004). Malaysian Indian (MI) patients exhibited exceedingly high expression of ERG in their tumors, almost doubling that of Malaysian Chinese (MC) patients, whereas ERG expression was very low amongst Malay patients (12.5%). When collectively analyzing data, we observed a significant correlation between younger patients and higher ERG expression (P=0.04). The prevalence of ERG expression was significantly different amongst CaP patients of different ethnicities. The higher number of ERG-expressing tumors among MI patients suggested that the TMPRSS2-ERG fusion may be particularly important in the pathogenesis of CaP amongst this group of patients. Furthermore, the more frequent expression of ERG among the younger patients analyzed suggested an involvement of ERG in the early onset of CaP. The results of this study underline the value of using ERG status to better understand the differences in the etiology of CaP initiation and progression between ethnic groups. PMID:25469265
Kelly, Gregory M; Kong, Yink Heay; Dobi, Albert; Srivastava, Shiv; Sesterhenn, Isabell A; Pathmanathan, Rajadurai; Tan, Hui Meng; Tan, Shyh-Han; Cheong, Sok Ching
2015-01-01
84
SciTech Connect
Highlights: •Hominoid-specific oncogene TBC1D3 is targeted to plasma membrane by palmitoylation. •TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. •TBC1D3 palmitoylation governs growth factors-induced TBC1D3 degradation. •Post-translational modifications may regulate oncogenic properties of TBC1D3. -- Abstract: Expression of the hominoid-specific oncoprotein TBC1D3 promotes enhanced cell growth and proliferation by increased activation of signal transduction through several growth factors. Recently we documented the role of CUL7 E3 ligase in growth factors-induced ubiquitination and degradation of TBC1D3. Here we expanded our study to discover additional molecular mechanisms that control TBC1D3 protein turnover. We report that TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. The expression of double palmitoylation mutant TBC1D3:C318/325S resulted in protein mislocalization and enhanced growth factors-induced TBC1D3 degradation. Moreover, ubiquitination of TBC1D3 via CUL7 E3 ligase complex was increased by mutating the palmitoylation sites, suggesting that depalmitoylation of TBC1D3 makes the protein more available for ubiquitination and degradation. The results reported here provide novel insights into the molecular mechanisms that govern TBC1D3 protein degradation. Dysregulation of these mechanisms in vivo could potentially result in aberrant TBC1D3 expression and promote oncogenesis.
Kong, Chen; Lange, Jeffrey J.; Samovski, Dmitri [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Su, Xiong [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States); Liu, Jialiu [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Sundaresan, Sinju [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States)] [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States); Stahl, Philip D., E-mail: [email protected] [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)
2013-05-03
85
PubMed Central
Background Human papillomaviruses (HPV) are the causative agents of cervical cancer in women, which results in over 250 000 deaths per year. Presently there are two prophylactic vaccines on the market, protecting against the two most common high-risk HPV types 16 and 18. These vaccines remain very expensive and are not generally affordable in developing countries where they are needed most. Additionally, there remains a need to treat women that are already infected with HPV, and who have high-grade lesions or cervical cancer. Methods In this paper, we characterize the immunogenicity of a therapeutic vaccine that targets the E7 protein of the most prevalent high-risk HPV - type 16 – the gene which has previously been shown to be effective in DNA vaccine trials in mice. The synthetic shuffled HPV-16 E7 (16E7SH) has lost its transforming properties but retains all naturally-occurring CTL epitopes. This was genetically fused to Zera®, a self-assembly domain of the maize ?-zein able to induce the accumulation of recombinant proteins into protein bodies (PBs), within the endoplasmic reticulum in a number of expression systems. Results High-level expression of the HPV 16E7SH protein fused to Zera® in plants was achieved, and the protein bodies could be easily and cost-effectively purified. Immune responses comparable to the 16E7SH DNA vaccine were demonstrated in the murine model, with the protein vaccine successfully inducing a specific humoral as well as cell mediated immune response, and mediating tumour regression. Conclusions The fusion of 16E7SH to the Zera® peptide was found to enhance the immune responses, presumably by means of a more efficient antigen presentation via the protein bodies. Interestingly, simply mixing the free PBs and 16E7SH also enhanced immune responses, indicating an adjuvant activity for the Zera® PBs. PMID:24885328
2014-01-01
86
PubMed
The presence of HER-2/neu (c-erbB-2) oncoprotein, oestrogen-alpha receptor (ER), and progesterone receptor (PR) in hyperplastic endometrial polyps (EPs) of two cats with cystic endometrial hyperplasia-pyometra (CEH-P) complex was investigated. Immunohistochemistry assay for ER, PR and c-erbB-2 oncoprotein in the glandular and stromal tissue of the EPs was performed. ER and c-erbB-2 immunoreactivity was observed in the glandular epithelium of the EPs whereas PR immunoreactivity was detected only in the stromal fibroblasts. The c-erbB-2 oncoprotein may play a role with the ER in the pathogenesis of the hyperplastic EPs, although the role of this oncoprotein in the pathogenesis of EPs has yet to be determined. PMID:19560383
Misirlioglu, Deniz; Nak, Deniz; Ozyigit, Musa Ozgur; Nak, Yavuz; Akkoc, Ahmet
2009-10-01
87
PubMed
Interferon-gamma (IFN-gamma) is an essential regulator of innate and adaptive immune responses and a hallmark of the Th1 T-cell subset. It is produced at high levels by human T lymphocytes upon transformation with Herpesvirus saimiri, which depends on the expression of the viral oncoproteins saimiri transformation-associated protein of subgroup C (StpC) and tyrosine kinase-interacting protein (Tip). Here, we show that IFN-gamma production was induced by Tip in Jurkat T cells. StpC by itself did not affect IFN-gamma expression, but enhanced the effect of Tip. Our results substantiated the findings that StpC induces NF-kappaB activation and demonstrated that other transcription factors, including NFAT, AP-1 and serum response element regulators, were not activated by StpC in unstimulated T cells. Studies using StpC mutants deficient in NF-kappaB activation, dominant negative IkappaBalpha and constitutively active IKK2, established the importance of NF-kappaB in StpC-mediated upregulation of IFN-gamma production. These observations suggest that NF-kappaB induction by StpC contributes to the Th1-like phenotype of virus-transformed human T cells. PMID:18560378
Glanz, Anja; Albrecht, Jens-Christian; Heinemann, Stefanie; Fleckenstein, Bernhard; Isakov, Noah; Biesinger, Brigitte
2008-10-01
88
The tumor suppressor p53 is degraded by the ubiquitin-proteasome system. p53 was polyubiquitinated in the presence of E1, UbcH5 as E2 and MDM2 oncoprotein. A ubiquitin molecule bound MDM2 through sulfhydroxy bond which is characteristic of ubiquitin ligase (E3)-ubiquitin binding. The cysteine residue in the carboxyl terminus of MDM2 was essential for the activity. These data suggest that the MDM2
Reiko Honda; Hirofumi Tanaka; Hideyo Yasuda
1997-01-01
89
The adenovirus E1A oncoprotein stimulates cell growth and inhibits differentiation by deregulating the normal transcription program via interaction with positive and negative cellular effectors. E1A associates with transcriptional regulatory complexes containing p400 and TRRAP involved in chromatin remodeling and decondensation. TRRAP is a component of three distinct human histone acetyltransferase (HAT) complexes: the TIP60 complex and complexes containing GCN5 or
Steven E Lang; Patrick Hearing
2003-01-01
90
PubMed Central
Several mucosotropic human papillomaviruses (HPV), including HPV type 16 (HPV-16), are etiologic agents of a subset of anogenital cancers and head and neck squamous cell carcinomas. In mice, HPV-16 E7 is the most potent of the papillomaviral oncogenes in the development of cervical disease. Furthermore, interfering specifically with the expression of E7 in HPV-positive cell lines derived from human cervical cancers inhibits their ability to proliferate, indicating that the expression of E7 is important in maintaining the transformed phenotype in vitro. To assess the temporal role of E7 in maintaining HPV-associated tumors and precancerous lesions in vivo, we generated Bi-L E7 transgenic mice that harbor a tetracycline-inducible transgene that expresses both HPV-16 E7 and firefly luciferase. When we crossed Bi-L E7 mice to a K5-tTA transgene-inducing line of mice, which expresses a tetracycline-responsive transactivator selectively in the stratified squamous epithelia, the resulting Bi-L E7/K5-tTA bitransgenic mice expressed E7 and luciferase in the skin and cervical epithelium, and doxycycline repressed this expression. Bitransgenic mice displayed several overt and acute epithelial phenotypes previously shown to be associated with the expression of E7, and these phenotypes were reversed on treatment with doxycycline. Repressing the expression of E7 caused the regression of high-grade cervical dysplasia and established cervical tumors, indicating that they depend on the continuous expression of E7 for their persistence. These results suggest that E7 is a relevant target not only for anticancer therapy but also for the treatment of HPV-positive dysplastic cervical lesions. PMID:19435895
Jabbar, Sean F.; Abrams, Linda; Glick, Adam; Lambert, Paul F.
2010-01-01
91
PubMed
Phosphorylation of the alpha subunit of eukaryotic translation initiation factor 2 (eIF2alpha) at serine 51 inhibits protein synthesis in cells subjected to various forms of stress including virus infection. The human papillomavirus (HPV) E6 oncoprotein contributes to virus-induced pathogenicity through multiple mechanisms including the inhibition of apoptosis and the blockade of interferon (IFN) action. We have investigated a possible functional relationship between the E6 oncoprotein and eIF2alpha phosphorylation by an inducible-dimerization form of the IFN-inducible protein kinase PKR. Herein, we demonstrate that HPV type 18 E6 protein synthesis is rapidly repressed upon eIF2alpha phosphorylation caused by the conditional activation of the kinase. The remainder of E6, however, can rescue cells from PKR-mediated inhibition of protein synthesis and induction of apoptosis. E6 physically associates with GADD34/PP1 holophosphatase complex, which mediates translational recovery, and facilitates eIF2alpha dephosphorylation. Inhibition of eIF2alpha phosphorylation by E6 mitigates eIF2alpha-dependent responses to transcription and translation of proapoptotic genes. These findings demonstrate, for the first time, a role of the oncogenic E6 in apoptotic signaling induced by PKR and eIF2alpha phosphorylation. The functional interaction between E6 and the eIF2alpha phosphorylation pathway may have important implications for HPV infection and associated pathogenesis. PMID:15060162
Kazemi, Shirin; Papadopoulou, Stavroula; Li, Suiyang; Su, Qiaozhu; Wang, Shuo; Yoshimura, Akihiko; Matlashewski, Greg; Dever, Thomas E; Koromilas, Antonis E
2004-04-01
92
PubMed Central
Patients with HPV-positive oropharyngeal cancer show better tumor response to radiation or chemotherapy than patients with HPV-negative cancer. HPV oncoprotein E6 binds and degrades a typically wild-type p53 protein product. However, HPV16 infection and p53 mutation infrequently coexist in a subset of HNSCCs. The purpose of this study was to investigate the mechanisms through which tumor biology and molecular genetic mechanisms change when two HPV-negative, p53-mutated oropharyngeal cell lines (YD8, non-disruptive p53 mutation; YD10B, disruptive p53 mutation) derived from patients with a history of heavy smoking are transfected with HPV E6 and E7 oncogenes in vitro. Transfection with HPV E6 and E7 oncogenes in YD8, reduced the abundance of proteins encoded by tumor suppressor genes, such as p-p53 and p-Rb. Cell proliferative activity was increased in the cells transfected with E6E7 compared to cells transfected with vector alone (P=0.09), whereas the invasiveness of E6E7-transfected cells was significantly reduced (P=0.02). cDNA microarray of the transfected cells with E6E7 showed significant changes in mRNA expression in several signaling pathways, including focal adhesion, JAK-STAT signaling pathway, cell cycle and p53 signaling pathway. Regarding the qPCR array for the p53 signaling pathway, the mRNA expression of STAT1 was remarkably upregulated by 6.47-fold (P<0.05); in contrast, IGF-1R was significantly downregulated by 2.40-fold in the YD8-vector compared toYD8-E6E7 (P<0.01). Finally, data collected from these two array experiments enabled us to select two genes, STAT1 and IGF-1R, for further study. In immunohistochemical study, nuclear STAT1 expression was slightly higher in HPV-positive compared to HPV-negative oropharyngeal tumors (P=0.18); however, cytoplasmic STAT1 was significantly lower in HPV-positive cases (P=0.03). IGF-1R expression levels were remarkably lower in HPV-positive compared to HPV-negative cases (P=0.01). Our data suggest that upregulated STAT1 and interferon signals by HPV16 E6 and E7 genes may play a major role in the relatively favorable prognosis for HPV-positive oropharyngeal squamous cell carcinoma cases with non-disruptive p53 mutations. PMID:23708675
OH, JI-EUN; KIM, JEONG-OH; SHIN, JUNG-YOUNG; ZHANG, XIANG-HUA; WON, HYE-SUNG; CHUN, SANG-HOON; JUNG, CHAN-KWON; PARK, WON-SANG; NAM, SUK-WOO; EUN, JUNG-WOO; KANG, JIN-HYOUNG
2013-01-01
93
PubMed Central
ABSTRACT Using mass spectrometry, we identified p190RhoGAP (p190) as a binding partner of human papillomavirus 16 (HPV16) E7. p190 belongs to the GTPase activating protein (GAP) family and is one of the primary GAPs for RhoA. GAPs stimulate the intrinsic GTPase activity of the Rho proteins, leading to Rho inactivation and influencing numerous biological processes. RhoA is one of the best-characterized Rho proteins and is specifically involved in formation of focal adhesions and stress fibers, thereby regulating cell migration and cell spreading. Since this is the first report that E7 associates with p190, we carried out detailed interaction studies. We show that E7 proteins from other HPV types also bind p190. Furthermore, we found that conserved region 3 (CR3) of E7 and the middle domain of p190 are important for this interaction. More specifically, we identified two residues in CR3 of E7 that are necessary for p190 binding and used mutants of E7 with mutations of these residues to determine the biological consequences of the E7-p190 interaction. Our data suggest that the interaction of E7 with p190 dysregulates this GAP and alters the actin cytoskeleton. We also found that this interaction negatively regulates cell spreading on a fibronectin substrate and therefore likely contributes to important aspects of the HPV life cycle or HPV-induced tumorigenesis. IMPORTANCE This study identifies p190RhoGAP as a novel cellular binding partner for the human papillomavirus (HPV) E7 protein. Our study shows that a large number of different HPV E7 proteins bind p190RhoGAP, and it identifies regions in both E7 and p190RhoGAP which are important for the interaction to occur. This study also highlights the likelihood that the E7-p190RhoGAP interaction may have important biological consequences related to actin organization in the infected cell. These changes could be an important contributor to the viral life cycle and during progression to cancer in HPV-infected cells. Importantly, this work also emphasizes the need for further study in a field which has largely been unexplored as it relates to the HPV life cycle and HPV-induced transformation. PMID:24403595
Todorovic, Biljana; Nichols, Anthony C.; Chitilian, Jennifer M.; Myers, Michael P.; Shepherd, Trevor G.; Parsons, Sarah J.; Barrett, John W.; Banks, Lawrence
2014-01-01
94
PubMed
Evidence for transcriptional activation of the viral oncoproteins E6 and E7 is regarded as the gold standard for the presence of clinically relevant human papillomavirus (HPV), but detection of E6/E7 mRNA requires RNA extraction and polymerase chain reaction amplification-a challenging technique that is restricted to the research laboratory. The development of RNA in situ hybridization (ISH) probes complementary to E6/E7 mRNA permits direct visualization of viral transcripts in routinely processed tissues and has opened the door for accurate HPV detection in the clinical care setting. Tissue microarrays containing 282 head and neck squamous cell carcinomas from various anatomic subsites were tested for the presence of HPV using p16 immunohistochemistry, HPV DNA ISH, and an RNA ISH assay (RNAscope) targeting high-risk HPV E6/E7 mRNA transcripts. The E6/E7 mRNA assay was also used to test an additional 25 oropharyngeal carcinomas in which the HPV status as recorded in the surgical pathology reports was equivocal due to conflicting detection results (ie, p16 positive, DNA ISH negative). By the E6/E7 mRNA method, HPV was detected in 49 of 282 (17%) HNSCCs including 43 of 77 (56%) carcinomas from the oropharynx, 2 of 3 (67%) metastatic HNSCCs of an unknown primary site, 2 of 7 (29%) carcinomas from the sinonasal tract, and 2 of 195 (1%) carcinomas from other head and neck sites. p16 expression was strongly associated with the presence of HPV E6/E7 mRNA: 46 of 49 HPV-positive tumors exhibited p16 expression, whereas only 22 of 233 HPV-negative tumors were p16 positive (94% vs. 9%, P<0.0001). There was also a high rate of concordance (99%) between the E6/E7 mRNA method and HPV DNA ISH. For the selected group of discordant HNSCCs (p16/HPV DNA), the presence of E6/E7 transcripts was detected in 21 of 25 (84%) cases. The E6/E7 mRNA method confirmed the presence of transcriptionally active HPV-related HNSCC that has a strong predilection for the oropharynx and is strongly associated with high levels of p16 expression. Testing for HPV E6/E7 transcripts by RNA ISH is ideal because it confirms the presence of integrated and transcriptionally active virus, permits visualization of viral transcripts in tissues, and is technically feasible for routine testing in the clinical laboratory. PMID:23060353
Bishop, Justin A; Ma, Xiao-Jun; Wang, Hongwei; Luo, Yuling; Illei, Peter B; Begum, Shanaz; Taube, Janis M; Koch, Wayne M; Westra, William H
2012-12-01
95
PubMed Central
Background Evidence for transcriptional activation of the viral oncoproteins E6 and E7 is regarded as the gold standard for the presence of clinically relevant human papillomavirus (HPV), but detection of E6/E7 mRNA requires RNA extraction and PCR amplification - a challenging technique that is restricted to the research laboratory. The development of RNA in-situ hybridization (ISH) probes complementary to E6/E7 mRNA permits direct visualization of viral transcripts in routinely processed tissues and has opened the door for accurate HPV detection in the clinical care setting. Methods Tissue microarrays (TMAs) containing 282 head and neck squamous cell carcinomas (HNSCCs) from various anatomic subsites were tested for the presence of HPV using p16 immunohistochemistry, HPV DNA ISH, and a RNA ISH assay (RNAscope®) targeting high risk HPV E6/E7 mRNA transcripts. The E6/E7 mRNA assay was also used to test an additional 25 oropharyngeal carcinomas where HPV status as recorded in the surgical pathology reports was equivocal due to conflicting detection results (i.e. p16 positive, DNA ISH negative). Results By the E6/E7 mRNA method, HPV was detected in 49 of 282 (17%) HNSCCs including 43 of 77 (56%) carcinomas from the oropharynx, 2 of 3 (67%) metastatic HNSCCs of unknown primary site, 2 of 7 (29%) carcinomas from the sinonasal tract, and 2 of 195 (1%) carcinomas from other head and neck sites. P16 expression was strongly associated with the presence of HPV E6/E7 mRNA: 46 of 49 HPV positive tumors exhibited p16 expression, whereas only 22 of 233 HPV negative tumors were p16 positive (94% versus 9%, p < .0001). There was also a high rate of concordance (99%) between the E6/E7 mRNA method and HPV DNA ISH. For the selected group of discordant HNSCCs (p16+/HPV DNA-), the presence of E6/E7 transcripts was detected in 21 of 25 (84%) cases. Conclusions The E6/E7 mRNA method confirmed the presence of transcriptionally active HPV-related HNSCC that has a strong predilection for the oropharynx and is strongly associated with high levels of p16 expression. Testing for HPV E6/E7 transcripts by RNA ISH is ideal because it confirms the presence of integrated and transcriptionally active virus, permits visualization of viral transcripts in tissues, and is technically feasible for routine testing in the clinical laboratory. PMID:23060353
Bishop, JA; Ma, X-J; Wang, H; Luo, Y; Illei, PB; Begum, S; Taube, JM; Koch, WM; Westra, WH
2012-01-01
96
E-print Network
Direct Binding of the N-Terminus of HTLV-1 Tax Oncoprotein to Cyclin-Dependent Kinase 4 for immortalization and transformation of human T-cell leukemia virus 1 (HTLV-1) infected cells. In both p16 oncoprotein in HTLV-1 infected cells. Our current understanding of cell cycle control in eukary- otes
Tsai, Ming-Daw
97
PubMed Central
Oct4 is a widely recognized pluripotency factor as it maintains Embryonic Stem (ES) cells in a pluripotent state, and, in vivo, prevents the inner cell mass (ICM) in murine embryos from differentiating into trophectoderm. However, its function in somatic tissue after this developmental stage is not well characterized. Using a tamoxifen-inducible Cre recombinase and floxed alleles of Oct4, we investigated the effect of depleting Oct4 in mouse embryos between the pre-streak and headfold stages, ?E6.0–E8.0, when Oct4 is found in dynamic patterns throughout the embryonic compartment of the mouse egg cylinder. We found that depletion of Oct4 ?E7.5 resulted in a severe phenotype, comprised of craniorachischisis, random heart tube orientation, failed turning, defective somitogenesis and posterior truncation. Unlike in ES cells, depletion of the pluripotency factors Sox2 and Oct4 after E7.0 does not phenocopy, suggesting that ?E7.5 Oct4 is required within a network that is altered relative to the pluripotency network. Oct4 is not required in extraembryonic tissue for these processes, but is required to maintain cell viability in the embryo and normal proliferation within the primitive streak. Impaired expansion of the primitive streak occurs coincident with Oct4 depletion ?E7.5 and precedes deficient convergent extension which contributes to several aspects of the phenotype. PMID:24244203
DeVeale, Brian; Brokhman, Irina; Mohseni, Paria; Babak, Tomas; Yoon, Charles; Lin, Anthony; Onishi, Kento; Tomilin, Alexey; Pevny, Larysa; Zandstra, Peter W.; Nagy, Andras; van der Kooy, Derek
2013-01-01
98
PubMed Central
Infection by oncogenic viruses is a frequent cause for tumor formation as observed in cervical cancer. Viral oncoproteins cause inactivation of p53 function and false transcriptional regulation of central cell cycle genes. Here we analyze the regulation of Plk4, serving as an example of many cell cycle- and p53-regulated genes. Cell cycle genes are often repressed via CDE and CHR elements in their promoters and activated by NF-Y binding to CCAAT-boxes. In contrast, general activation of Plk4 depends on NRF1 and CRE sites. Bioinformatic analyses imply that NRF1 and CRE are central elements of the transcriptional network controlling cell cycle genes. We identify CDE and CHR sites in the Plk4 promoter, which are necessary for binding of the DREAM (DP, RB-like, E2F4 and MuvB) complex and for mediating repression in G0/G1. When cells progress to G2 and mitosis, DREAM is replaced by the MMB (Myb-MuvB) complex that only requires the CHR element for binding. Plk4 expression is downregulated by the p53-p21WAF1/CIP1-DREAM signaling pathway through the CDE and CHR sites. Cell cycle- and p53-dependent repression is abrogated by HPV E7 oncoprotein. Together with genome-wide analyses our results imply that many cell cycle genes upregulated in tumors by viral infection are bound by DREAM through CDE/CHR sites. PMID:24071582
Fischer, Martin; Quaas, Marianne; Wintsche, Axel; Müller, Gerd A.; Engeland, Kurt
2014-01-01
99
PubMed Central
Abstract Antigen-specific immunotherapy and vascular disrupting agents, such as 5,6-dimethylxanthenone-4-acetic acid (DMXAA), have emerged as attractive approaches for the treatment of cancers. In the current study, we tested the combination of DMXAA treatment with therapeutic human papillomavirus type 16 (HPV-16) E7 peptide-based vaccination for their ability to generate E7-specific CD8+ T-cell immune responses, as well as their ability to control E7-expressing tumors in a subcutaneous and a cervicovaginal tumor model. We found that the combination of DMXAA treatment with E7 long peptide (amino acids 43–62) vaccination mixed with polyriboinosinic:polyribocytidylic generated significantly stronger E7-specific CD8+ T-cell immune responses and antitumor effects compared with treatment with DMXAA alone or HPV peptide vaccination alone in the subcutaneous model. Additionally, we found that the DMXAA-mediated enhancement of E7-specific CD8+ T-cell immune responses generated by the therapeutic HPV peptide-based vaccine was dependent on the timing of administration of DMXAA. Treatment with DMXAA in tumor-bearing mice was also shown to lead to increased dendritic cell maturation and increased production of inflammatory cytokines in the tumor. Furthermore, we observed that the combination of DMXAA with HPV-16 E7 peptide vaccination generated a significant enhancement in the antitumor effects in the cervicovaginal TC-1 tumor growth model, which closely resembles the tumor microenvironment of cervical cancer. Taken together, our data demonstrated that administration of the vascular disrupting agent, DMXAA, enhances therapeutic HPV vaccine-induced cytotoxic T-lymphocyte responses and antitumor effects against E7-expressing tumors in two different locations. Our study has significant implications for future clinical translation. PMID:21128743
Zeng, Qi; Peng, Shiwen; Monie, Archana; Yang, Ming; Pang, Xiaowu; Hung, Chien-Fu
2011-01-01
100
PubMed Central
Human papillomavirus (HPV) infection is the leading cause of cancer mortality among women worldwide. The life-threatening infection caused by HPV demands the need for designing anticancerous drugs. In the recent years, different compounds from natural origins, such as carrageenan, curcumin, epigallocatechin gallate, indole-3-carbinol, jaceosidin, and withaferin, have been used as a hopeful source of anticancer therapy. These compounds have been shown to suppress HPV infection by different researchers. In the present study, we explored these natural inhibitors against E6 oncoprotein of high-risk HPV-16, which is known to inactivate the p53 tumor suppressor protein. A robust homology model of HPV-16 E6 was built to anticipate the interaction mechanism of E6 oncoprotein with natural inhibitory molecules using a structure-based drug designing approach. Docking analysis showed the interaction of these natural compounds with the p53-binding site of E6 protein residues 113-122 (CQKPLCPEEK) and helped the restoration of p53 functioning. Docking analysis, besides helping in silico validation of natural compounds, also helps understand molecular mechanisms of protein-ligand interactions. PMID:25031569
Jena, Lingaraja; Galande, Sneha; Daf, Sangeeta; Mohod, Kanchan; Varma, Ashok K.
2014-01-01
101
PubMed
Human T cells are transformed to antigen-independent permanent growth in vitro upon infection with herpesvirus saimiri subgroup C strains. The viral oncoproteins required for this process, StpC and Tip, could be replaced by Tio, the oncoprotein of herpesvirus ateles. Here we demonstrate that proliferation of lymphocytes transformed with Tio-recombinant herpesvirus saimiri required the activity of Src family kinases. Src kinases had previously been identified as interaction partners of Tio. This interaction was now shown to be independent of any of the four tyrosine residues of Tio but to be dependent on an SH3-binding motif. Mutations within this motif abrogated the transforming capabilities of Tio-recombinant herpesvirus saimiri. Furthermore, kinase interaction resulted in the phosphorylation of Tio on a single tyrosine residue at position 136. Mutation of this residue in the viral context revealed that this phosphorylation site, but none of the other tyrosine residues, was required for T-cell transformation. These data indicate that the interaction of Tio with a Src kinase is essential for both the initiation and the maintenance of T-cell transformation by recombinant herpesvirus saimiri. The requirement for the tyrosine phosphorylation site at position 136 suggests a role for Tio beyond simple deregulation of the kinase. PMID:16051843
Albrecht, Jens-Christian; Müller-Fleckenstein, Ingrid; Schmidt, Monika; Fleckenstein, Bernhard; Biesinger, Brigitte
2005-08-01
102
PubMed Central
Human T cells are transformed to antigen-independent permanent growth in vitro upon infection with herpesvirus saimiri subgroup C strains. The viral oncoproteins required for this process, StpC and Tip, could be replaced by Tio, the oncoprotein of herpesvirus ateles. Here we demonstrate that proliferation of lymphocytes transformed with Tio-recombinant herpesvirus saimiri required the activity of Src family kinases. Src kinases had previously been identified as interaction partners of Tio. This interaction was now shown to be independent of any of the four tyrosine residues of Tio but to be dependent on an SH3-binding motif. Mutations within this motif abrogated the transforming capabilities of Tio-recombinant herpesvirus saimiri. Furthermore, kinase interaction resulted in the phosphorylation of Tio on a single tyrosine residue at position 136. Mutation of this residue in the viral context revealed that this phosphorylation site, but none of the other tyrosine residues, was required for T-cell transformation. These data indicate that the interaction of Tio with a Src kinase is essential for both the initiation and the maintenance of T-cell transformation by recombinant herpesvirus saimiri. The requirement for the tyrosine phosphorylation site at position 136 suggests a role for Tio beyond simple deregulation of the kinase. PMID:16051843
Albrecht, Jens-Christian; Müller-Fleckenstein, Ingrid; Schmidt, Monika; Fleckenstein, Bernhard; Biesinger, Brigitte
2005-01-01
103
PubMed
The E6 protein of the high-risk human papillomavirus type 16 (HPV-16) is involved in the tumorigenesis of human cervical cells by targeting numerous cellular proteins. We characterized new anti-E6 monoclonal antibodies and used them for precise localization of the E6 oncoprotein within carcinoma cells. Overexpressed E6 protein was predominantly detected in the nucleus of transiently transfected HaCaT cells. While mostly localized at the periphery of condensed chromatin, E6 was also associated with nuclear ribonucleoproteic ultrastructures and with some ribosomal areas in the cytoplasm of SiHa and CaSki cells. The chimeric beta-galactosidase-E6 protein expressed in transfected HeLa cells was essentially localized in the nuclear compartment. Together, these data indicate that the E6 sequence of HPV-16 may encode a nuclear localization signal. The preferential nuclear distribution of this viral oncoprotein in HPV-transformed cells correlates with its activities at the transcriptional level. PMID:12867640
Masson, Murielle; Hindelang, Colette; Sibler, Annie-Paule; Schwalbach, Georges; Travé, Gilles; Weiss, Etienne
2003-08-01
104
PubMed
Human papillomavirus (HPV) infection is the leading cause of cancer mortality among women worldwide. The life-threatening infection caused by HPV demands the need for designing anticancerous drugs. In the recent years, different compounds from natural origins, such as carrageenan, curcumin, epigallocatechin gallate, indole-3-carbinol, jaceosidin, and withaferin, have been used as a hopeful source of anticancer therapy. These compounds have been shown to suppress HPV infection by different researchers. In the present study, we explored these natural inhibitors against E6 oncoprotein of high-risk HPV-16, which is known to inactivate the p53 tumor suppressor protein. A robust homology model of HPV-16 E6 was built to anticipate the interaction mechanism of E6 oncoprotein with natural inhibitory molecules using a structure-based drug designing approach. Docking analysis showed the interaction of these natural compounds with the p53-binding site of E6 protein residues 113-122 (CQKPLCPEEK) and helped the restoration of p53 functioning. Docking analysis, besides helping in silico validation of natural compounds, also helps understand molecular mechanisms of protein-ligand interactions. PMID:25031569
Kumar, Satish; Jena, Lingaraja; Galande, Sneha; Daf, Sangeeta; Mohod, Kanchan; Varma, Ashok K
2014-06-01
105
PubMed Central
The catalytic and regulatory subunits of class I phosphoinositide 3-kinase (PI3K) have oncogenic potential. The catalytic subunit p110? and the regulatory subunit p85 undergo cancer-specific gain-of-function mutations that lead to enhanced enzymatic activity, ability to signal constitutively and oncogenicity. The ?, ? and ? isoforms of p110 are cell-transforming as overexpressed wild-type proteins. Class I PI3Ks have the unique ability to generate phosphoinositide 3,4,5 trisphosphate (PIP3). Class II and class III PI3Ks lack this ability. Genetic and cell biological evidence suggests that PIP3 is essential for PI3K-mediated oncogenicity, explaining why class II and class III enzymes have not been linked to cancer. Mutational analysis reveals the existence of at least two distinct molecular mechanisms for the gain of function seen with cancer-specific mutations in p110?, one causing independence from upstream receptor tyrosine kinases, the other inducing independence from Ras. An essential component of the oncogenic signal that is initiated by PI3K is the TOR (target of rapamycin) kinase. TOR is an integrator of growth and of metabolic inputs. In complex with the raptor protein (TORC1), it controls cap-dependent translation, and this function is essential for PI3K-initiated oncogenesis. PMID:20582532
Vogt, Peter K.; Hart, Jonathan R.; Gymnopoulos, Marco; Jiang, Hao; Kang, Sohye; Bader, Andreas G.; Zhao, Li; Denley, Adam
2010-01-01
106
PubMed
The lack of a human papillomavirus (HPV)-infected skin cancer cell line has hampered the investigation of the interaction of UV and HPV in skin carcinogenesis. We identified a human basal cell carcinoma (BCC-1/KMC) cell line integrated with E6 and E7 genes of high-risk HPV type 18 and demonstrated that repression of E6 and E7 results in proliferation inhibition. Sublethal ultraviolet-B (UVB) irradiation induced the expressions of interleukin-6 (IL-6) and interleukin-8 (IL-8), as well as viral E6 and E7 genes, in BCC-1/KMC cells. When E6 and E7 expressions were inhibited, IL-6/IL-8 expressions were repressed. Furthermore, IL-6/IL-8 remained inducible by UVB irradiation when E6 and E7 were inhibited. These results indicated that IL-6 and IL-8 can be upregulated by viral E6 and E7 proteins without UVB irradiation. Moreover, chronic exposure to UVB upregulates IL-6 and IL-8 when E6/E7 is induced by UVB. PMID:24079741
Hsiao, Yu-Ping; Yang, Jen-Hung; Wu, Wen-Jun; Lin, Meng-Hsuan; Sheu, Gwo-Tarng
2013-10-01
107
E-print Network
Intracellular scFvs against the viral E6 oncoprotein provoke apoptosis in human papillomavirus : 10.1016/j.bbrc.2007.07.040 #12;ABSTRACT The E6 protein of Human papillomavirus type 16 (16E6 infection with high-risk human papillomaviruses (HPVs) [1]. Epidemiological studies have demonstrated
108
E-print Network
cells transformed by high-LET radiation G. CALAF* and T. K. HEI (Received 24 March 2000; accepted 13 of oncoproteins that are frequently altered in breast ing of the natural history of breast tumors. These cancer staining coupled with confocal microscopy tion, i.e. deregulated proliferation and invasion. in transformed
109
PubMed
Kaposi's sarcoma herpesvirus (KSHV) latent oncoprotein viral FLICE (FADD-like interferon converting enzyme)-like inhibitory protein (v-FLIP) or K13, a potent activator of NF-?B, has well-established roles in KSHV latency and oncogenesis. KSHV-induced COX-2 represents a novel strategy employed by KSHV to promote latency and inflammation/angiogenesis/invasion. Here, we demonstrate that v-FLIP/K13 promotes tumorigenic effects via the induction of host protein COX-2 and its inflammatory metabolite PGE2 in an NF-?B-dependent manner. In addition to our previous studies demonstrating COX-2/PGE2's role in transcriptional regulation of KSHV latency promoter and latent gene expression, the current study adds to the complexity that though LANA-1 (latency associated nuclear antigen) is utilizing COX-2/PGE2 as critical factors for its transcriptional regulation, it is the v-FLIP/K13 gene in the KSHV latency cluster that maintains continuous COX-2/PGE2 levels in the infected cells. We demonstrate that COX-2 inhibition, via its chemical inhibitors (NS-398 or celecoxib), reduced v-FLIP/K13-mediated NF-?B induction, and extracellular matrix (ECM) interaction-mediated signaling, mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) levels, and subsequently downregulated detachment-induced apoptosis (anoikis) resistance. vFLIP expression mediated the secretion of cytokines, and spindle cell differentiation activated the phosphorylation of p38, RSK, FAK, Src, Akt and Rac1-GTPase. The COX-2 inhibition in v-FLIP/K13-HMVECs reduced inflammation and invasion/metastasis-related genes, along with reduced anchorage-independent colony formation via modulating 'extrinsic' as well as 'intrinsic' cell death pathways. COX-2 blockade in v-FLIP/K13-HMVEC cells drastically augmented cell death induced by removal of essential growth/survival factors secreted in the microenvironment. Transformed cells obtained from anchorage-independent colonies of COX-2 inhibitor-treated v-FLIP/K13-HMVEC cells expressed lower levels of endothelial-mesenchymal transition genes such as slug, snail and twist, and higher expression of the tumor-suppressor gene, E-cadherin. Taken together, our study provides strong evidences that FDA-approved COX-2 inhibitors have great potential in blocking tumorigenic events linked to KSHV's oncogenic protein v-FLIP/K13. PMID:23552603
Sharma-Walia, N; Patel, K; Chandran, K; Marginean, A; Bottero, V; Kerur, N; Paul, A G
2012-01-01
110
PubMed Central
Human papillomavirus 16 (HPV16) is a high-risk DNA tumour virus which is the primary causative agent of cervical cancer. Cell transformation arises from deregulated expression of the E6 and E7 oncogenes. E6 has been shown to bind a number of cellular proteins, including p53 and proteins containing a PDZ domain. This study reports the first RNA aptamers to E6. These have been employed as molecular tools to further investigate E6-p53 and E6-PDZ interactions. This study is focussed on two aptamers (termed F2 and F4) which induced apoptosis in cells derived from an HPV16-transformed cervical carcinoma. The molecules were able to inhibit the interaction between E6 and PDZ1 from Magi1, with F2 being the most effective inhibitor. Neither of the aptamers inhibited E6-p53 interaction or p53 degradation. This study shows the specificity of this approach and highlights the potential benefits of the E6 aptamers as potential therapeutic or diagnostic agents in the future. PMID:25062098
Belyaeva, Tamara A.; Nicol, Clare; Cesur, Özlem; Travé, Gilles; Blair, George Eric; Stonehouse, Nicola J.
2014-01-01
111
PubMed
Nasopharyngeal carcinoma (NPC), which is closely associated with Epstein-Barr virus (EBV), is a metastasis-prone epithelial cancer. We previously showed that tumor necrosis factor ?-induced protein 2 (TNFAIP2) is highly expressed in NPC tumor tissues and is correlated with metastasis and poor survival in NPC patients. However, the underlying mechanism remains unclear. In this study, we demonstrate that the EBV oncoprotein, latent membrane protein 1 (LMP1), can transcriptionally induce TNFAIP2 expression via NF-?B. Quantitative RT-PCR and western blotting revealed that LMP1 induces TNFAIP2 expression through its C-terminal-activating region (CTAR2) domain, which is required for transduction of NF-?B (nuclear factor kappa-light-chain-enhancer of activated B cells) signaling. Inhibition of NF-?B activation or depletion of p65 (a component of NF-?B) by RNA interference abolished the LMP1-induced expression of TNFAIP2, whereas ectopic expression of p65 was sufficient to induce TNFAIP2 expression. Luciferase reporter assays showed that LMP1 transcriptionally induces TNFAIP2 expression through a newly identified NF-?B-binding site within the TNFAIP2 promoter (-3,869 to -3,860?bp). Immunohistochemical analysis of NPC biopsy specimens further revealed a significant correlation between the protein levels of TNFAIP2 and activated p65 (R=0.689, P<0.001), indicating that our findings are clinically relevant. Immunofluorescence microscopy and co-immunoprecipitation assays showed that TNFAIP2 associates with actin and is involved in the formation of actin-based membrane protrusions. Furthermore, transwell migration assays demonstrated that TNFAIP2 contributes to LMP1-induced cell motility. Collectively, these findings provide novel insights into the regulation of TNFAIP2 and its role in promoting NPC tumor progression. PMID:23975427
Chen, C-C; Liu, H-P; Chao, M; Liang, Y; Tsang, N-M; Huang, H-Y; Wu, C-C; Chang, Y-S
2014-07-10
112
PubMed Central
Cancers can be addicted to continued and relatively high expression of nuclear oncoproteins. This is evident in colorectal cancer (CRC) where the oncoprotein and transcription factor MYB is over expressed and essential to continued proliferation and tumour cell survival. Historically, targeting transcription factors in the context of cancer has been very challenging. Nevertheless, we formulated a DNA vaccine to generate a MYB-specific immune response in the belief MYB peptides might be aberrantly presented on the cell surface of CRC cells. MYB, like many tumour antigens, is weakly immunogenic as it is a ‘self' antigen and is subject to tolerance. To break tolerance, a fusion vaccine was generated comprising a full-length MYB complementary DNA (cDNA) flanked by two potent CD4-epitopes derived from tetanus toxoid. Vaccination was achieved against tumours initiated by two distinct highly aggressive, syngeneic cancer cell lines (CT26 and MC38) that express MYB. This was done in BALB/c and C57BL/6 mouse strains respectively. We introduced multiple inactivating mutations into the oncogene sequence for safety and sub-cloned the cDNA into a Food and Drug Administration (FDA)-compliant vector. We used low dose cyclophosphamide (CY) to overcome T-regulatory cell immune suppression, and anti-program cell death receptor 1 (anti-PD-1) antibodies to block T-cell exhaustion. Anti-PD-1 administered alone slightly delayed tumour growth in MC38 and more effectively in CT26 bearing mice, while CY treatment alone did not. We found that therapeutic vaccination elicits protection when MC38 tumour burden is low, mounts tumour-specific cell killing and affords enhanced protection when MC38 and CT26 tumour burden is higher but only in combination with anti-PD-1 antibody or low dose CY, respectively.
Cross, Ryan S; Malaterre, Jordane; Davenport, Alexander J; Carpinteri, Sandra; Anderson, Robin L; Darcy, Phillip K; Ramsay, Robert G
2015-01-01
113
PubMed
Cancers can be addicted to continued and relatively high expression of nuclear oncoproteins. This is evident in colorectal cancer (CRC) where the oncoprotein and transcription factor MYB is over expressed and essential to continued proliferation and tumour cell survival. Historically, targeting transcription factors in the context of cancer has been very challenging. Nevertheless, we formulated a DNA vaccine to generate a MYB-specific immune response in the belief MYB peptides might be aberrantly presented on the cell surface of CRC cells. MYB, like many tumour antigens, is weakly immunogenic as it is a 'self' antigen and is subject to tolerance. To break tolerance, a fusion vaccine was generated comprising a full-length MYB complementary DNA (cDNA) flanked by two potent CD4-epitopes derived from tetanus toxoid. Vaccination was achieved against tumours initiated by two distinct highly aggressive, syngeneic cancer cell lines (CT26 and MC38) that express MYB. This was done in BALB/c and C57BL/6 mouse strains respectively. We introduced multiple inactivating mutations into the oncogene sequence for safety and sub-cloned the cDNA into a Food and Drug Administration (FDA)-compliant vector. We used low dose cyclophosphamide (CY) to overcome T-regulatory cell immune suppression, and anti-program cell death receptor 1 (anti-PD-1) antibodies to block T-cell exhaustion. Anti-PD-1 administered alone slightly delayed tumour growth in MC38 and more effectively in CT26 bearing mice, while CY treatment alone did not. We found that therapeutic vaccination elicits protection when MC38 tumour burden is low, mounts tumour-specific cell killing and affords enhanced protection when MC38 and CT26 tumour burden is higher but only in combination with anti-PD-1 antibody or low dose CY, respectively. PMID:25671128
Cross, Ryan S; Malaterre, Jordane; Davenport, Alexander J; Carpinteri, Sandra; Anderson, Robin L; Darcy, Phillip K; Ramsay, Robert G
2015-01-01
114
E-print Network
We examine conservation of the E7(7) Noether-Gaillard-Zumino current in the presence of N=8 supergravity counterterms using the momentum space helicity formalism, which significantly simplifies the calculations. The main result is that the 4-point counterterms at any loop order L are forbidden by the E7(7) current conservation identity. We also clarify the relation between linearized and full non-linear superinvariants as candidate counterterms. This enables us to show that all n-point counterterms at L=7, 8 are forbidden since they provide a non-linear completions of the 4-point ones. This supports and exemplifies our general proof in arXiv:1103.4115 of perturbative UV finiteness of N=8 supergravity.
Renata Kallosh
2011-04-28
115
Equilibrium phase diagrams of uncured and UV-cured difunctional hexanedioldiacrylate and the eutectic mixture of low molecular weight liquid crystals E7 are established by polarized optical microscopy and differential scanning calorimetry. Data are analyzed using the Maier-Saupe model of nematic order. In the case of the uncured system the Flory-Huggins free energy of isotropic mixing is applied while for the cured
F. Roussel; U. Maschke; J.-M. Buisine; X. Coqueret; F. Benmouna
2001-01-01
116
E-print Network
Journal of Plant Ecology VolumE 7, NumbEr 1, PagEs 86Â96 FEbruary 2014 doi:10.1093/jpe/rtt016, Beijing 100049, China 3 Department of Plant and Soil Science, University of Vermont, Burlington VT 05405 of the Fungal phospholipid fatty acids (PlFas)/ bacterial PlFas ratio. Fungal PlFa values were greater
Neher, Deborah A.
117
HE bcl-2 gene was initially discovered by virtue of its T involvement in t( 14; 181 (q32;q21) chromosomal translocations that are found in the majority of non-Hodg- kin's lymphomas (NHLs).' This gene encodes a 26-Kd in- tegral membrane protein that appears to reside at least in part in mitochondria, and that promotes the survival of sev- eral types of hematolymphoid
Toshiyuki Miyashita; John C. Reed
1993-01-01
118
PubMed Central
Vaccines prevent HPV-associated cancer but, although these tumors express foreign, viral antigens (E6 and E7 proteins), they have little benefit in established malignancies, likely due to negative environmental cues that block tumor recognition and induce T cell anergy in vivo. We postulated that we could identify mechanisms by which ex vivo stimulation of T cells could reactivate and expand tumor-directed T-cell lines from HPV-positive cancer patients for subsequent adoptive immunotherapy. A total of 68 patients with HPV-associated cancers were studied. Peripheral blood T cells were stimulated with monocyte-derived dendritic cells loaded with pepmixes (peptide libraries of 15-mers overlapping by 11 amino-acids) spanning E6/E7, in the presence or absence of specific accessory cytokines. The resulting T-cell lines were further expanded with pepmix-loaded activated B-cell blasts. IFN? release and cytotoxic responses to E6/E7 were assessed. We successfully reactivated and expanded (>1200-fold) E6/E7-specific T cells from 8/16 cervical and 33/52 oropharyngeal cancer patients. The presence of the cytokines IL-6, -7, -12 and -15 is critical for this process. These T cell lines possess the desirable characteristics of polyclonality, multiple T-cell subset representation (including the memory compartment) and a TH1 bias, and may eliminate E6/E7-positive targets. In conclusion, we have shown it is possible to robustly generate HPV16 E6/E7-directed T-cell lines from patients with HPV16-associated cancers. Because our technique is scalable and good-manufacturing-procedures compliant, these lines could be used for adoptive cellular immunotherapy of patients with HPV16-positive cancers. PMID:23211628
Ramos, Carlos A.; Narala, Neeharika; Vyas, Gayatri M.; Leen, Ann M.; Gerdemann, Ulrike; Sturgis, Erich M.; Anderson, Matthew L.; Savoldo, Barbara; Heslop, Helen E.; Brenner, Malcolm K.; Rooney, Cliona M.
2012-01-01
119
Oncoprotein 18 (Op18; also termed p19, 19K, metablastin, stathmin, and prosolin) is a conserved protein that regulates microtubule (MT) dynamics. Op18 is multisite phosphorylated on four Ser residues during mitosis; two of these Ser residues, Ser-25 and Ser-38, are targets for cyclin-dependent protein kinases (CDKs), and the other two Ser residues, Ser-16 and Ser-63, are targets for an unidentified protein
1997-01-01
120
PubMed
Although Saimiri Transforming Protein (STP)-A11, an oncoprotein of Herpesvirus saimiri, has been known to activate NF-kappaB signaling pathway, the detailed mechanism has not been reported yet. We herein report that STP-A11 activates non-canonical NF-kappaB pathway, resulting in p100 processing to p52. In addition, translocation of p52 protein (NF-kappaB2) into the nucleus is observed by the expression of STP-A11. STP-A11-mediated processing of p100 to p52 protein requires proteosome-mediated proteolysis because MG132 treatment clearly blocked p52 production in spite of the expression of STP-A11. Analysis of STP-A11 mutants to activate NF-kappaB2 pathway discloses the requirement of TRAF6-binding site not Src-binding site for STP-A11-mediated NF-kappaB2 pathway. Blockage of STP-A11-mediated p52 production using siRNA against p52 enhanced a chemotherapeutic drug-mediated cell death, suggesting that p52 production induced by the expression of STP-A11 would contribute to cellular transformation, which results from a resistance to cell death. PMID:17028057
Cho, Il-Rae; Jeong, Sunam; Jhun, Byung Hak; An, Won G; Lee, BokSoo; Kwak, Youn-Tae; Lee, Sun-Hwa; Jung, Jae U; Chung, Young-Hwa
2007-03-01
121
PubMed
Human T cell leukemia virus type 1 (HTLV-1) is the etiologic agent of a number of pathologic abnormalities, including adult T cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The viral oncoprotein Tax has been implicated in the pathogenesis of these diseases. Recently, cell-free Tax was detected in the cerebrospinal fluid of HAM/TSP patients, implying that extracellular Tax may be relevant to neurologic disease. Additionally, the presence of a nuclear export signal within Tax and its active secretion has been demonstrated in vitro. However, the mechanism of Tax secretion remains to be established. Studies reported herein elucidate the process of Tax secretion and identify domains of Tax critical to its subcellular localization and secretion. Tax was shown to interact with a number of cellular secretory pathway proteins in both the model cell line BHK (baby hamster kidney)-21 and an HTLV-1-infected T cell line, C8166, physiologically relevant to HTLV-1-induced disease. Silencing of selected components of the secretory pathway affected Tax secretion, further confirming regulated secretion of Tax. Additionally, mutations in two putative secretory signals within Tax DHE and YTNI resulted in aberrant subcellular localization of Tax and significantly altered protein secretion. Together, these studies demonstrate that Tax secretion is a regulated event facilitated by its interactions with proteins of the cellular secretory pathway and the presence of secretory signals within the carboxyl-terminal domain of the protein. PMID:17897946
Jain, Pooja; Mostoller, Kate; Flaig, Katherine E; Ahuja, Jaya; Lepoutre, Veronique; Alefantis, Timothy; Khan, Zafar K; Wigdahl, Brian
2007-11-23
122
PubMed
Breast cancer is the commonest cancer affecting females in Malaysia, contributing 31% of all newly diagnosed cases amongst Malaysian women. The present retrospective cohort study evaluated the relationship between cerbB- 2 onco-protein overexpression with various tumour characteristics and survival rate of breast cancer patients treated at the Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between 1996-2000. CerbB- 2 oncoprotein overexpression was determined by immunohistochemistry (IHC) and tumors showing 2+ positivity were verified by Fluorescence In Situ Hybridization (FISH). One hundred and seventy two patients were eligible for the study with a short-term follow-up (median) of 5.1 years. C-erbB-2 oncoprotein overexpression correlated with lymph node positivity, oestrogen receptor (ER) and progesterone receptor (PR) negativity. Univariate analyses showed shorter disease free survival (DFS) and overall survival (OS) in patients with cerbB- 2 oncoprotein overexpression, Malay ethnicity, higher tumour grade, lymph node positivity, ER and PR negativity. In a subgroup of patients with c-erbB-2 oncoprotein overexpression, a shorter OS was observed in those with lymph node positivity, ER and PR negativity. In multivariate prognostic analysis, lymph node status, ER status and tumour grading were the strongest independent prognostic factors for both OS and DFS. However, c-erbB-2 status was not a significantly independent prognostic factor, even in subsets with lymph node positive or negative group. C-erbB-2 oncoprotein overexpression correlated well with lymph node status, ER and PR. Shorter OS and DFS were significantly observed in patients with c-erbB-2 oncoprotein overexpression. Lymph node status, ER status and tumour grading were the only three independent prognostic factors for OS and DFS in this study. Although c-erbB-2 expression is obviously important from a biological standpoint, multivariate analysis showed that it is not an independent prognostic indicator in breast carcinoma in the local population. PMID:19271345
Sharifah, N A; Lee, B R; Clarence-Ko, C H; Tan, G C; Shiran, M S; Naqiyah, I; Rohaizak, M; Fuad, I; Tamil, A M
2008-01-01
123
PubMed Central
Thyroid carcinomas that harbor RET/PTC oncogenes are well differentiated, relatively benign neoplasms compared with those expressing oncogenic RAS or BRAF mutations despite signaling through shared transforming pathways. A distinction, however, is that RET/PTCs induce immunostimulatory programs, suggesting that, in the case of this tumor type, the additional pro-inflammatory pathway reduces aggressiveness. Here, we demonstrate that pro-inflammatory programs are selectively activated by TRAF2 and TRAF6 association with RET/PTC oncoproteins. Eliminating this mechanism reduces pro-inflammatory cytokine production without decreasing transformation efficiency. Conversely, ablating MEK/ERK or PI3K/AKT signaling eliminates transformation but not pro-inflammatory cytokine secretion. Functional uncoupling of the two pathways demonstrates that intrinsic pro-inflammatory pathways are not required for cellular transformation and suggests a need for further investigation into the role inflammation plays in thyroid tumor progression. PMID:22158616
Wixted, Josephine H. F.; Rothstein, Jay L.; Eisenlohr, Laurence C.
2012-01-01
124
Code of Federal Regulations, 2011 CFR
...7 Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...
2011-10-01
125
Code of Federal Regulations, 2013 CFR
...Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...
2013-10-01
126
Code of Federal Regulations, 2014 CFR
...Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...
2014-10-01
127
Code of Federal Regulations, 2012 CFR
...Section 52e.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.7 What are the terms and conditions of...
2012-10-01
128
PubMed
The ultimate success of cancer vaccination is dependent upon the generation of tumor-specific CTLs. In this study, we designed and evaluated a novel fusion protein comprising a cell penetrating and immunostimulatory peptide corresponding to residues 32-51 of the Limulus polyphemus protein (LALF(32-51)) linked to human papillomavirus (HPV) 16 E7 antigen (LALF(32-51)-E7). We demonstrated that LALF(32-51) penetrates the cell membrane and delivers E7 into cells. In a preclinical model of HPV16-induced cervical carcinoma we showed that vaccination with adjuvant-free LALF(32-51)-E7 fusion protein significantly improves the presentation of E7-derived peptides to T-cells in vitro and induces suppression of tumor growth. PMID:21145912
Granadillo, Milaid; Vallespi, Maribel G; Batte, Aileen; Mendoza, Osmany; Soria, Yordanka; Lugo, Victoria M; Torrens, Isis
2011-01-29
129
PubMed
RNA helicase A (RHA), a member of the DEXH box helicase family of proteins, is an integral component of protein complexes that regulate transcription and splicing. The EWS-FLI1 oncoprotein is expressed as a result of the chromosomal translocation t(11;22) that occurs in patients with the Ewing's sarcoma family of tumors (ESFT). Using phage display library screening, we identified an EWS-FLI1 binding peptide containing homology to RHA. ESFT cell lines and patient tumors highly expressed RHA. GST pull-down and ELISA assays showed that EWS-FLI1 specifically bound RHA fragment amino acids 630 to 1020, which contains the peptide region discovered by phage display. Endogenous RHA was identified in a protein complex with EWS-FLI1 in ESFT cell lines. Chromatin immunoprecipitation experiments showed both EWS-FLI1 and RHA bound to EWS-FLI1 target gene promoters. RHA stimulated the transcriptional activity of EWS-FLI1 regulated promoters, including Id2, in ESFT cells. In addition, RHA expression in mouse embryonic fibroblast cells stably transfected with EWS-FLI1 enhanced the anchorage-independent phenotype above that with EWS-FLI1 alone. These results suggest that RHA interacts with EWS-FLI1 as a transcriptional cofactor to enhance its function. PMID:16740692
Toretsky, Jeffrey A; Erkizan, Verda; Levenson, Amy; Abaan, Ogan D; Parvin, Jeffrey D; Cripe, Timothy P; Rice, Anna M; Lee, Sean Bong; Uren, Aykut
2006-06-01
130
PubMed Central
The E5 oncoprotein is the major transforming protein of bovine papillomavirus type 1. This 44-residue transmembrane protein can interact with the platelet-derived growth factor receptor ?, leading to ligand-independent activation and cell transformation. For productive interaction, E5 needs to dimerize via a C-terminal pair of cysteines, though a recent study suggested that its truncated transmembrane segment can dimerize on its own. To analyze the structure of the full protein in a membrane environment and elucidate the role of the Cys-Ser-Cys motif, we produced recombinantly the wild-type protein and four cysteine mutants. Comparison by circular dichroism in detergent micelles and lipid vesicular dispersion and by NMR in trifluoroethanol demonstrates that the absence of one or both cysteines does not influence the highly ?-helical secondary structure, nor does it impair the ability of E5 to dimerize, observations that are further supported by sodium dodecylsulfate polyacrylamide gel electrophoresis. We also observed assemblies of higher order. Oriented circular dichroism in lipid bilayers shows that E5 is aligned as a transmembrane helix with a slight tilt angle, and that this membrane alignment is also independent of any cysteines. We conclude that the Cys-containing motif represents a disordered region of the protein that serves as an extra covalent connection for stabilization. PMID:20858420
Windisch, Dirk; Hoffmann, Silke; Afonin, Sergii; Vollmer, Stefanie; Benamira, Soraya; Langer, Birgid; Bürck, Jochen; Muhle-Goll, Claudia; Ulrich, Anne S.
2010-01-01
131
PubMed
E5 is the major transforming oncoprotein of bovine papillomavirus, which activates the platelet-derived growth factor receptor ? in a highly specific manner. The short transmembrane protein E5 with only 44 residues interacts directly with the transmembrane segments of the receptor, but structural details are not available. Biophysical investigations are challenging, because the hydrophobic E5 protein tends to aggregate and get cross-linked non-specifically via two Cys residues near its C-terminus. Here, we demonstrate that a truncation by 10 amino acids creates a more manageable protein that can be conveniently used for structure analysis. Synchrotron radiation circular dichroism and solid-state (15)N- and (31)P-nuclear magnetic resonance spectroscopy show that this E5 variant serves as a representative model for the wild-type protein. The helical conformation of the transmembrane segment, its orientation in the lipid bilayer, and the ability to form homodimers in the membrane are not affected by the C-terminal truncation. PMID:25324446
Windisch, Dirk; Ziegler, Colin; Bürck, Jochen; Ulrich, Anne S
2014-12-01
132
PubMed Central
The Ski oncoprotein has been found to bind non-specifically to DNA in association with unindentified nuclear factors. In addition, Ski has been shown to activate transcription of muscle-specific and viral promoters/enhancers. The present study was undertaken to identify Ski's DNA binding and transcriptional activation partners by identifying specific DNA binding sites. We used nuclear extracts from a v-Ski-transduced mouse L-cell line and selected Ski-bound sequences from a pool of degenerate oligonucleotides with anti-Ski monoclonal antibodies. Two sequences were identified by this technique. The first (TGGC/ANNNNNT/GCCAA) is the previously identified binding site of the nuclear factor I (NFI) family of transcription factors. The second (TCCCNNGGGA) is the binding site of Olf-1/EBF. By electophoretic mobility shift assays we find that Ski is a component of one or more NFI complexes but we fail to detect Ski in Olf-1/EBF complexes. We show that Ski binds NFI proteins and activates transcription of NFI reporters, but only in the presence of NFI. We also find that homodimerization of Ski is essential for co-activation with NFI. However, the C-terminal dimerization domain of c-Ski, which is missing in v-Ski, can be substituted by the leucine zipper domain of GCN4. PMID:9380514
Tarapore, P; Richmond, C; Zheng, G; Cohen, S B; Kelder, B; Kopchick, J; Kruse, U; Sippel, A E; Colmenares, C; Stavnezer, E
1997-01-01
133
PubMed
The Ewings Sarcoma Oncoprotein (EWS) interacts with several components of the mammalian transcriptional and pre-mRNA splicing machinery and is also found in the cytoplasm and even on the cell surface. The apparently diverse cellular functions of EWS are, however, not well characterized. EWS harbours a potent N-terminal transcriptional activation domain (the EAD) that is revealed in the context of oncogenic EWS-fusion proteins (EFPs) and a C-terminal RNA-binding domain (RBD) that recruits pre-mRNA splicing factors and may couple transcription and splicing. In contrast to EFPs, the presumed transcriptional role of normal EWS remains enigmatic. Here, we report that multiple RGG-boxes within the RBD are necessary and sufficient for cis-repression of the EAD and that RGG-boxes can also repress in-trans, within dimeric partners. Lys can functionally substitute for Arg, indicating that the basic nature of the Arg side chain is the critical determinant of RGG-box-mediated repression. In addition to the EAD, RGG-boxes can repress a broad range of activation domains (including those of VP16, E1a and CREB), but repression can be alleviated by the simultaneous presence of more than one activation domain. We therefore propose that a key function of RGG boxes within native EWS is to restrict promiscuous activation by the EAD while still allowing EWS to enter functional transcription complexes and participate in other transactions involving pre-mRNAs. PMID:15743974
Alex, Deepa; Lee, Kevin A W
2005-01-01
134
E-print Network
Human papillomavirus 16 E7 inactivator of retinoblastoma family proteins complements human tested whether the human papillomavirus type 16 E7 protein, which inactivates pRb family proteins papillomavirus (HPV), of which certain subtypes cause cervical cancer (2). The HPV16 E7 protein binds
135
PubMed
High-risk human papillomaviruses (HPVs), including HPV-16 and HPV-18, are the causative agents of cervical carcinomas and are linked to several other tumors of the anogenital and oropharyngeal regions. The majority of HPV-induced tumors contain integrated copies of the normally episomal HPV genome that invariably retain intact forms of the two HPV oncogenes E6 and E7. E6 induces degradation of the cellular tumor suppressor p53, while E7 destabilizes the retinoblastoma (Rb) protein. Previous work has shown that loss of E6 function in cervical cancer cells induces p53 expression as well as downstream effectors that induce apoptosis and cell cycle arrest. Similarly, loss of E7 allows increased Rb expression, leading to cell cycle arrest and senescence. Here, we demonstrate that expression of a bacterial Cas9 RNA-guided endonuclease, together with single guide RNAs (sgRNAs) specific for E6 or E7, is able to induce cleavage of the HPV genome, resulting in the introduction of inactivating deletion and insertion mutations into the E6 or E7 gene. This results in the induction of p53 or Rb, leading to cell cycle arrest and eventual cell death. Both HPV-16- and HPV-18-transformed cells were found to be responsive to targeted HPV genome-specific DNA cleavage. These data provide a proof of principle for the idea that vector-delivered Cas9/sgRNA combinations could represent effective treatment modalities for HPV-induced cancers. Importance: Human papillomaviruses (HPVs) are the causative agents of almost all cervical carcinomas and many other tumors, including many head and neck cancers. In these cancer cells, the HPV DNA genome is integrated into the cellular genome, where it expresses high levels of two viral oncogenes, called E6 and E7, that are required for cancer cell growth and viability. Here, we demonstrate that the recently described bacterial CRISPR/Cas RNA-guided endonuclease can be reprogrammed to target and destroy the E6 or E7 gene in cervical carcinoma cells transformed by HPV, resulting in cell cycle arrest, leading to cancer cell death. We propose that viral vectors designed to deliver E6- and/or E7-specific CRISPR/Cas to tumor cells could represent a novel and highly effective tool to treat and eliminate HPV-induced cancers. PMID:25100830
Kennedy, Edward M; Kornepati, Anand V R; Goldstein, Michael; Bogerd, Hal P; Poling, Brigid C; Whisnant, Adam W; Kastan, Michael B; Cullen, Bryan R
2014-10-01
136
PubMed
Hepatitis B X-interacting protein (HBXIP) is a novel oncoprotein. We have previously reported that HBXIP promotes the proliferation and migration of breast cancer cells. S-phase kinase-associated protein 2 (Skp2) is another oncoprotein which is important for migration. In this study, we investigated whether Skp2 is involved in the migration enhanced by HBXIP in ovarian cancer. The expression of HBXIP and Skp2 in ovarian cancer tissues was examined by immunohistochemistry using tissue microarrays. The role of HBXIP and Skp2 in the migration of ovarian cancer cells was investigated by wound-healing assay and Transwell migration assay. The effect of HBXIP on Skp2 was assessed by reverse transcription polymerase chain reaction (RT-PCR), western blot analysis, luciferase reporter gene assays and chromatin immunoprecipitation in ovarian cancer cells (SKOV3 and CAOV3). We found that both HBXIP and Skp2 were highly expressed in ovarian cancer tissues. We observed that the overexpression of HBXIP enhanced the migration of ovarian cancer cells, while Skp2 siRNAs decreased the cell migration enhanced by HBXIP. The HBXIP siRNAs inhibited ovarian cancer cell migration and Skp2 rescued the migration inhibition induced by HBXIP siRNA. HBXIP could upregulate Skp2 at the levels of mRNA and protein in ovarian cancer cells. Moreover, HBXIP increased the activity of Skp2 promoter via binding to the transcription factor Sp1. HBXIP is highly expressed in ovarian cancer tissues. HBXIP enhances the migration of ovarian cancer cells. HBXIP was able to stimulate the activity of Skp2 promoter via transcription factor Sp1 thus promoting the migration of ovarian cancer cells. PMID:24788380
Xu, Fuqiang; Zhu, Xiaoming; Han, Tao; You, Xiaona; Liu, Fabao; Ye, Lihong; Zhang, Xiaodong; Wang, Xiaohong; Yao, Yuanqing
2014-07-01
137
PubMed Central
Oncoprotein DEK plays an important role in cancer tumorigenesis. To explore the clinical implication of DEK expression on prognostic evaluation in small cell lung cancer (SCLC), 130 cases of SCLC with strict follow-up were selected for immunohistochemical (IHC) staining of DEK protein. The correlation between DEK expression and clinicopathological features of SCLC was evaluated using the Chi-square and Fisher’s exact tests, survival rates were calculated using the Kaplan-Meier method and univariate and multivariate analyses were performed using the Cox proportional hazards regression model. IHC analysis demonstrated that DEK protein staining was strongly positive and significantly higher (44.62%) in SCLC compared with either adjacent non-tumor or normal lung tissues (P < 0.001 for both). DEK expression correlated with large tumor size (P = 0.025) and late pathologic stage (P = 0.005). Moreover, it correlated with low disease-free (P = 0.004) and 5-year (P = 0.005) survival rates. In the late-stage group, disease-free and 5-year survival rates of patients with high level DEK expression were significantly lower than those with low level DEK expression (P = 0.006 and P = 0.001, respectively). Furthermore, Cox analysis revealed that DEK expression emerged as a significant independent hazard factor for the overall survival rate of patients with SCLC (HR: 1.594, 95% CI: 1.087-2.336, P = 0.017). In conclusion, DEK plays an important role in the progression of SCLC. DEK may potentially be used as an independent biomarker for the prognostic evaluation of SCLC. PMID:25197373
Wang, Xiaoyan; Lin, Lijuan; Ren, Xiangshan; Lin, Zhenhua; Li, Zhuhu; Li, Chunyu; Jin, Tiefeng
2014-01-01
138
BackgroundNeoplastic transformation originates from a large number of different genetic alterations. Despite this genetic variability, a common phenotype to transformed cells is cellular alkalinization. We have previously shown in human keratinocytes and a cell line in which transformation can be turned on and followed by the inducible expression of the E7 oncogene of human papillomavirus type 16 (HPV16), that intracellular
Rosa A. Cardone; Giovanni Busco; Maria R. Greco; Antonia Bellizzi; Rosita Accardi; Antonella Cafarelli; Stefania Monterisi; Pierluigi Carratù; Valeria Casavola; Angelo Paradiso; Massimo Tommasino; Stephan J. Reshkin; Dong-Yan Jin
2008-01-01
139
SciTech Connect
The E7 protein of high-risk human papillomaviruses (HR HPVs) targets pRb family members (pRb, p107 and p130) for degradation; low-risk (LR) HPV E7 only targets p130 for degradation. The effect of HR HPV 16 E7 and LR HPV 6 E7 on p130 intracellular localization and half-life was examined. Nuclear/cytoplasmic fractionation and immunofluorescence showed that, in contrast to control and HPV 6 E7-expressing cells, a greater amount of p130 was present in the cytoplasm in the presence of HPV 16 E7. The half-life of p130, relative to control cells, was decreased in the cytoplasm in the presence of HPV 6 E7 or HPV 16 E7, but only decreased by HPV 6 E7 in the nucleus. Inhibition of proteasomal degradation extended the half-life of p130, regardless of intracellular localization. These results suggest that there may be divergent mechanisms by which LR and HR HPV E7 target p130 for degradation.
Barrow-Laing, Lisa; Chen Wei [Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Roman, Ann, E-mail: [email protected] [Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States)
2010-05-10
140
PubMed Central
PURPOSE: Foxhead box M1 (FOXM1) expression has been shown to be linked with human papillomavirus (HPV) 16/18–infected cervical cancer. However, the mechanism underlying the induction of FOXM1 in HPV 16/18–infected cancers remains elusive. EXPERIMENTAL DESIGN: The mechanistic actions of FOXM1 induced by the E6/NKX2-1 axis in tumor aggressiveness were elucidated in cellular and animal models. The prognostic value of FOXM1 for overall survival (OS) and relapse-free survival (RFS) in HPV-positive oral and lung cancers was assessed using Kaplan-Meier and Cox regression models. RESULTS: Herein, FOXM1 expression is upregulated by E6-mediated NKX2-1 in HPV-positive cervical, oral, and lung cancer cells. Induction of FOXM1 by E6 through the MZF1/NKX2-1 axis is responsible for HPV-mediated soft agar growth, invasiveness, and stemness through activating Wnt/?-catenin signaling pathway. In a nude mice model, metastatic lung tumor nodules in HPV 18 E6-positive GNM or HPV 16 E6-positive TL-1–injected nude mice were markedly decreased in both cell types with E6 knockdown, FOXM1 knockdown, or treatment with FOXM1 inhibitor (thiostrepton). Among the four subgroup patients, the worst FOXM1 prognostic value for OS and RFS was observed in HPV 16/18–positive patients with tumors with high-expressing FOXM1. CONCLUSIONS: Induction of FOXM1 by E6 oncoprotein through the MZF1/NKX2-1 axis may be responsible for HPV 16/18–mediated tumor progression and poor outcomes in HPV-positive patients. PMID:25425970
Chen, Po-Ming; Cheng, Ya-Wen; Wang, Yao-Chen; Wu, Tzu-Chin; Chen, Chih-Yi; Lee, Huei
2014-01-01
141
PubMed Central
The SET oncoprotein participates in cancer progression by affecting multiple cellular processes, inhibiting the tumor suppressor PP2A and inhibiting the metastasis suppressor nm23-H1. Based upon these multiple activities, we hypothesized that targeted inhibition of SET would have multiple discrete and measurable effects on cancer cells. Here, the effects of inhibiting SET oncoprotein function on intracellular signaling and proliferation of human cancer cell lines was investigated. We observed the effects of COG112, a novel SET interacting peptide, on PP2A activity, Akt signaling, nm23-H1 activity, and cellular migration/invasion in human U87 glioblastoma and MDA-MB-231 breast adenocarcinoma cancer cell lines. We found that COG112 interacted with SET protein and inhibited the association between SET and PP2A-c or nm23-H1. The interaction between COG112 and SET caused PP2A phosphatase, and nm23-H1 exonuclease activities, to increase. COG112-mediated increases in PP2A activity resulted in the inhibition of Akt signaling and cellular proliferation. Additionally, COG112 inhibited SET association with Rac1 leading to decreased cellular migration and invasion. COG112 treatment releases the SET-mediated inhibition of the tumor suppressor PP2A, as well as the metastasis suppressor nm23-H1. These results establish SET as a novel molecular target, and that the inhibition of SET may have beneficial effects in cancer chemotherapy. PMID:21297667
Switzer, Christopher H.; Cheng, Robert Y.S.; Vitek, Timothy M.; Christensen, Dale J.; Wink, David A.; Vitek, Michael P.
2010-01-01
142
PubMed Central
Background Human papilloma virus type 16 (HPV16)-induced gynecological cancers, in particular cervical cancers, are found in many women worldwide. The HPV16 encoded oncoproteins E6 and E7 are tumor-specific targets for the adaptive immune system permitting the development of an HPV16-synthetic long peptide (SLP) vaccine with an excellent treatment profile in animal models. Here, we determined the toxicity, safety, immunogenicity and efficacy of the HPV16 SLP vaccine in patients with advanced or recurrent HPV16-induced gynecological carcinoma. Methods Patients with HPV16-positive advanced or recurrent gynecological carcinoma (n?=?20) were subcutaneously vaccinated with an HPV16-SLP vaccine consisting of a mix of 13 HPV16 E6 and HPV16 E7 overlapping long peptides in Montanide ISA-51 adjuvant. The primary endpoints were safety, toxicity and tumor regression as determined by RECIST. In addition, the vaccine-induced T-cell response was assessed by proliferation and associated cytokine production as well as IFN?-ELISPOT. Results No systemic toxicity beyond CTCAE grade II was observed. In a few patients transient flu-like symptoms were observed. In 9 out of 16 tested patients vaccine-induced HPV16-specific proliferative responses were detected which were associated with the production of IFN?, TNF?, IL-5 and/or IL-10. ELISPOT analysis revealed a vaccine-induced immune response in 11 of the 13 tested patients. The capacity to respond to the vaccine was positively correlated to the patient’s immune status as reflected by their response to common recall antigens at the start of the trial. Median survival was 12.6 ± 9.1?months. No regression of tumors was observed among the 12 evaluable patients. Nineteen patients died of progressive disease. Conclusions The HPV16-SLP vaccine was well tolerated and induced a broad IFN?-associated T-cell response in patients with advanced or recurrent HPV16-induced gynecological carcinoma but neither induced tumor regression nor prevented progressive disease. We, therefore, plan to use this vaccine in combination with chemotherapy and immunomodulation. PMID:23557172
2013-01-01
143
The role of oncoproteins and tumor suppressor proteins in promoting the malignant transformation of mammalian cells by affecting properties such as proliferative signalling, cell cycle regulation and altered adhesion is well established. Chemicals, viruses and radiation are also generally accepted as agents that commonly induce mutations in the genes encoding these cancer-causing proteins, thereby giving rise to cancer. However, more
Stephen J. Ralph; Sara Rodríguez-Enríquez; Jiri Neuzil; Emma Saavedra; Rafael Moreno-Sánchez
2010-01-01
144
PubMed
Hox proteins control genetic programs that orchestrate development, and a large subset of Hox proteins can bind DNA elements as heterodimers with the Pbx family of homeodomain proteins. A transcriptionally activated version of Pbx1, E2a-Pbx1, is an oncoprotein in human pre-B cell leukemia that strongly suppresses differentiation and retains its ability to heterodimerize with Hox proteins. Because monomeric Hox proteins bind very similar DNA motifs, it is unclear how they activate diverse developmental programs. Here we demonstrate that heterodimers containing different Hox proteins and a common Pbx1 or E2a-Pbx1 partner bind different DNA motifs. Structural models suggest that the specificity of the Hox protein is altered by a conformation change involving residues in the N-terminal arm of the Hox homeodomain. Mutational analysis also supported the hypothesis that unique sequences in the N-terminal arm of the Hox homeodomain are at least partially responsible for mediating this specificity. In vivo, Hox proteins directed E2a-Pbx1-mediated transactivation with moderate specificity to cognate Hox-Pbx motifs. Thus, the development specificity of individual Hox proteins may be mediated, in part, by differential targeting of cellular genes by Pbx1-Hox complexes. Likewise, through its function as a common heterodimer partner, oncoprotein E2a-Pbx1 may be able to interfere with multiple programs of development that are induced by the sequential or simultaneous expression of Hox proteins during hematopoiesis. PMID:9010234
Lu, Q; Kamps, M P
1997-01-01
145
SciTech Connect
Down-regulation of transcription of the MHC class I genes in HPV16 tumorigenic cells is partly due to HPV16E7 associated with the MHC class I promoter and repressed chromatin activation. In this study, we further demonstrated that HPV16E7 is physically associated with a putative RXR{beta} binding motif (GGTCA) of the proximal promoter of the MHC class I genes by using reporter transcriptional assays and chromatin immunoprecipitation assays. Our data also provide evidence that HPV16E7 inhibits TNF-{alpha}-induced up-regulation of MHC class I transcription by impaired nuclear translocation of NF-{kappa}B. More importantly, CaSki tumor cells treated with TSA and transfected with the constitutively active mutant form of IKK-{alpha} (which can activate NF-{kappa}B directly) showed a maximal level of up-regulation of MHC-I expression. Taken together, our results suggest that HPV16E7 may employ two independent mechanisms to ensure that either the constitutive or inducible transcription of MHC class I genes is down-regulated.
Li, Hui; Zhan, TaiLan; Li, Chang [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China)] [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China); Liu, Mugen, E-mail: [email protected] [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China)] [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China); Wang, Qing K., E-mail: [email protected] [Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan (China); Center for Cardiovascular Genetics, Cleveland Clinic, Cleveland, OH 44195 (United States)
2009-10-16
146
PubMed Central
A new promoter located within E6 was mapped in human papillomavirus type 6b (HPV6b)- and HPV11-containing benign genital condylomata (genital warts). The RNA transcribed from this promoter represented the major RNA species colinear with open reading frames E6 and E7 and can encode the E7 protein. No equivalent promoter was active in HPV16-containing cancers and cancer-derived cell lines. In those, the major transcripts contained one of two different introns within E6 and the RNAs could encode two different E6 proteins and E7. Images PMID:2536845
Smotkin, D; Prokoph, H; Wettstein, F O
1989-01-01
147
PubMed Central
ABSTRACT High-risk types of human papillomavirus (HPV) are the causative agents of virtually all cases of cervical cancer and a significant proportion of other anogenital cancers, as well as both oral and pharyngeal cancers. The high-risk types encode two viral oncogenes, E6 and E7, which work together to initiate cell transformation. Multiple steps involving the activities and interactions of both viral and cellular proteins are involved in the progression from HPV infection to cell transformation to cancer. The E6 oncoprotein is expressed as several isoforms: a full-length variant referred to as E6 and a few shorter isoforms collectively referred to as E6*. In this study, we found that expression of E6* increased the level of reactive oxygen species (ROS) in both HPV-positive and HPV-negative cells. This increased oxidative stress led to higher levels of DNA damage, as assessed by the comet assay, quantification of 8-oxoguanine, and poly(ADP-ribose) polymerase 1. The observed increase in ROS may be due to a decrease in cellular antioxidant activity, as we found that E6* expression also led to decreased expression of superoxide dismutase isoform 2 and glutathione peroxidase. These studies indicate that E6* may play an important role in virus-induced mutagenesis by increasing oxidative stress and DNA damage. IMPORTANCE Our findings demonstrate for the first time that an HPV gene product, E6*, can increase ROS levels in host cells. This ability may play a significant role both in the viral life cycle and in cancer development, because an increase in oxidative DNA damage may both facilitate HPV genome amplification and increase the probability of HPV16 DNA integration. Integration, in turn, is thought to be an important step in HPV-mediated carcinogenesis. PMID:24696478
Williams, Vonetta M.; Filippova, Maria; Filippov, Valery; Payne, Kimberly J.
2014-01-01
148
E-print Network
London School of Hygiene & Tropical Medicine Keppel Street, London WC1E 7HT, UK Switchboard: +44 (0 A global community The London School of Hygiene & Tropical Medicine is a world-leading centre for research
Maizels, Rick
149
HTLV-1 Tax oncoprotein interacts with various cellular factors and modulates transcription and the cell cycle. To identify more cellular targets, we employed the yeast two hybrid system with Tax using a human cDNA library, and isolated a cDNA encoding the human counterpart of Drosophila discs large tumor suppressor protein, hDLG. Tax binding to hDLG was confirmed in vitro and also
Takeshi Suzuki; Yohta Ohsugi; Masami Uchida-Toita; Tetsu Akiyama; Mitsuaki Yoshida
1999-01-01
150
While human T-cell leukemia virus type 1 (HTLV-1) is associated with the development of adult T-cell leukemia (ATL), HTLV-2 has not been reported to be associated with such malignant leukemias. HTLV-1 Tax1 oncoprotein transforms a rat fibroblast cell line (Rat-1) to form multiple large colonies in soft agar, and this activity is much greater than that of HTLV-2 Tax2. We
Akira Hirata; Masaya Higuchi; Akiko Niinuma; Minako Ohashi; Masaya Fukushi; Masayasu Oie; Tetsu Akiyama; Yuetsu Tanaka; Fumitake Gejyo; Masahiro Fujii
2004-01-01
151
It has been speculated that immunological mechanisms play an important role in the control of carcinomas associated with human papillomavirus (HPV), such as cervical cancers. We have now demonstrated that immunization of C3H\\/HeN mice by syngeneic nontumorigenic fibroblast-like cells that contain the transfected HPV-16 E7 gene conferred protection against transplanted cells from a HPV-16 E7-positive syngeneic tumor. This protection was
Lieping Chen; Elaine Kinney Thomas; Shiu-Lok Hu; Ingegerd Hellstrom; Karl Erik Hellstrom
1991-01-01
152
PubMed Central
The SMRT corepressor complex participates in transcriptional repression by a diverse array of vertebrate transcription factors. The ability to recruit SMRT appears to play a crucial role in leukemogenesis by the PML-retinoic acid receptor ? (RAR?) oncoprotein, an aberrant nuclear hormone receptor implicated in human acute promyelocytic leukemia (APL). Arsenite induces clinical remission of APL through a incompletely understood mechanism. We report here that arsenite is a potent inhibitor of the interaction of SMRT with its transcription factor partners, including PML-RAR?. Arsenite operates, in part, through a mitogen-activated protein (MAP) kinase cascade culminating in phosphorylation of the SMRT protein, dissociation of SMRT from its nuclear receptor partners, and a relocalization of SMRT out of the nucleus into the cytoplasm of the cell. Conversely, inhibition of this MAP kinase cascade attenuates the effects of arsenite on APL cells. Our results implicate SMRT as an important biological target for the actions of arsenite in both normal and neoplastic cells. PMID:11585900
Hong, Suk-Hyun; Yang, Zhihong; Privalsky, Martin L.
2001-01-01
153
Infection of a human retrovirus HTLV-1 induces adult T cell leukemia and a neurological disease, HAM\\/TSP. Regulatory protein Tax of HTLV-1 is thought to contribute to the pathogenesis. We have studied the mechanism of transcriptional activation induced by Tax protein and identified two independent mechanisms: (a) binding to the enhancer-binding proteins, CREB, CREM, NF-?B and SRF, resulting in the activation
Mitsuaki Yoshida
1995-01-01
154
PubMed
Kaposi's sarcoma herpesvirus oncoprotein vFLIP K13 is a potent activator of NF-kappaB and plays a key role in viral pathogenesis. K13 contains a putative TRAF-interacting motif, which is reportedly required for its interaction with TRAF2. The K13-TRAF2 interaction is believed to be essential for the recruitment of K13 to the I-kappaB kinase (IKK) complex and for K13-induced NF-kappaB and JNK activation. In addition, TRAF3 has been reported to be required for K13-induced NF-kappaB and JNK activation. We have re-examined the role of the TRAFs in K13 signaling and report that mutations in the putative TRAF-interacting motif of K13 have no deleterious effect on its ability to interact with the IKK complex or activation of the NF-kappaB pathway. Furthermore, endogenously expressed TRAF2 and TRAF3 do not interact with K13 and play no role in K13-induced NF-kappaB activation or its interaction with the IKK complex. Finally, K13 does not activate the JNK pathway. Our results support a model in which K13 bypasses the upstream components of the tumor necrosis factor receptor signaling pathway and directly interacts with the IKK complex to selectively activate the NF-kappaB pathway without affecting the JNK pathway. Selective NF-kappaB activation by K13 might represent a novel strategy employed by the virus to promote latency. PMID:17597077
Matta, Hittu; Mazzacurati, Lucia; Schamus, Sandra; Yang, Tianbing; Sun, Qinmiao; Chaudhary, Preet M
2007-08-24
155
We have previously shown that the degradation of c-myc and N-myc in vitro is mediated by the ubiquitin system. However, the role of the system in targeting the myc proteins in vivo and the identity of the conjugating enzymes and possible ancillary proteins involved has remained obscure. Here we report that the degradation of the myc proteins in cells is
Shlomit Gross-Mesilaty; Eyal Reinstein; Beatrice Bercovich; Karin E. Tobias; Alan L. Schwartz; Chaim Kahana; Aaron Ciechanover
1998-01-01
156
PubMed
The high-risk Alpha-types of human papillomavirus (HPV) are the causative agent of cervical cancer, which is the second major cause of death among women worldwide. Recent investigations have shown that E7 from the Alpha-papillomavirus HPV-16 interacts with IKK? and IKK? of the IKK complex in the NF-?B pathway leading to an attenuation of the activity. There is a possible link between development of non-melanoma skin cancer and cutaneous Beta-papillomavirus but if these HPV types attenuate the NF-?B pathway is unclear. Seven different E7 proteins, representing four out of the five different species of the Beta genus (HPV-20, -37, -38, -92, -93 and -96) and one from the Gamma genus (HPV-4) were investigated for potential modulation of the NF-?B pathway in U2OS cells. Our results demonstrate that E7 from all the cutaneous HPV types were capable of inhibiting the NF-?B activity as well as E7 from HPV-16. In addition, E7 proteins from the cutaneous HPV types demonstrated interaction with IKK? but not with IKK?. The deregulation of the NF-?B pathway by cutaneous HPVs might contribute to the pathogenesis of non-melanoma skin cancers and its precursors. PMID:22776252
Byg, Luise M; Vidlund, Jessica; Vasiljevic, Natasa; Clausen, Dorte; Forslund, Ola; Norrild, Bodil
2012-10-01
157
PubMed Central
The c-myc oncogene is among the most commonly overexpressed genes in human cancer. c-myc encodes a basic helix–loop–helix/leucine zipper (bHLH/LZ) transcription factor (c-MYC) that activates a cascade of downstream targets that ultimately mediate cellular transformation. Although a large number of genes are regulated by c-MYC, only a few have been functionally linked to c-MYC-mediated transformation. By expression profiling, the metastasis-associated protein 1 (MTA1) gene was identified here as a target of the c-MYC oncoprotein in primary human cells, a result confirmed in human cancer cells. MTA1 itself has been previously implicated in cellular transformation, in part through its ability to regulate the epithelial-to-mesenchymal transition and metastasis. MTA1 is a component of the Mi-2/nucleosome remodeling and deacetylating (NURD) complex that contains both histone deacetylase and nucleosome remodeling activity. The data reported here demonstrate that endogenous c-MYC binds to the genomic MTA1 locus and recruits transcriptional coactivators. Most importantly, short hairpin RNA (shRNA)-mediated knockdown of MTA1 blocks the ability of c-MYC to transform mammalian cells. These data implicate MTA1 and the Mi-2/NURD complex as one of the first downstream targets of c-MYC function that are essential for the transformation potential of c-MYC. PMID:16172399
Zhang, Xiao-yong; DeSalle, Lauren M.; Patel, Jagruti H.; Capobianco, Anthony J.; Yu, Duonan; Thomas-Tikhonenko, Andrei; McMahon, Steven B.
2005-01-01
158
PubMed Central
We developed a new phage-display based approach, the Large Fragment Phage Display (LFPD), that can be used for mapping conformational epitopes on target molecules of immunological interest. LFPD uses a simplified and more effective phage-display approach in which only a limited set of larger fragments (about 100 aa in length) are expressed on the phage surface. Using the human HER2 oncoprotein as a target, we identified novel B-cell conformational epitopes. The same homologous epitopes were also detected in rat HER2 and all corresponded to the epitopes predicted by computational analysis (PEPITO software), showing that LFPD gives reproducible and accurate results. Interestingly, these newly identified HER2 epitopes seem to be crucial for an effective immune response against HER2-overexpressing breast cancers and might help discriminating between metastatic breast cancer and early breast cancer patients. Overall, the results obtained in this study demonstrated the utility of LFPD and its potential application to the detection of conformational epitopes on many other molecules of interest, as well as, the development of new and potentially more effective B-cell conformational epitopes based vaccines. PMID:23555577
Gabrielli, Federico; Salvi, Roberto; Garulli, Chiara; Kalogris, Cristina; Arima, Serena; Tardella, Luca; Monaci, Paolo; Pupa, Serenella M.; Tagliabue, Elda; Montani, Maura; Quaglino, Elena; Stramucci, Lorenzo; Curcio, Claudia
2013-01-01
159
PubMed Central
Over-expression of the oncoprotein, Aurora A kinase occurs in multiple types of carcinomas, often early during cell transformation. To identify mechanism(s) contributing to enhanced Aurora A protein expression, we examined normal human lung fibroblast and breast epithelial cells and compared them to non-tumorigenic breast (MCF10A and MCF12A) and tumorigenic breast and cervical epithelial cell lines (MCF-7 and HeLa S3, respectively). A subset of these immortalized lines (MCF10, MCF12A, and HeLa S3) exhibited increased levels of Aurora A protein, independent of tumorigenicity. The increase in Aurora A protein expression in these immortalized cells was not due to increased transcription/RNA stability, protein half-life or cap-dependent translation. Assays utilizing monocistronic and dicistronic RNA constructs revealed that the Aurora A 5? leader contains an internal ribosomal entry site (IRES), which is regulated through the cell cycle, peaking in G2/M phase. Moreover, IRES activity was increased in the immortalized cell lines in which Aurora A protein expression was also enhanced. Additional assays indicated that the increased internal initiation is specific to the Aurora A IRES and may be an early event during cancer progression. Taken together, these results identify a novel mechanism contributing to Aurora A kinase over-expression and possibly to immortalization leading to carcinogenesis. PMID:23661421
Dobson, Tara; Chen, Juan; Krushel, Les A.
2014-01-01
160
SciTech Connect
Highlights: •HBXIP is able to upregulate the expression of PDGFB in breast cancer cells. •HBXIP serves as a coactivator of activating transcription factor Sp1. •HBXIP stimulates the PDGFB promoter via activating transcription factor Sp1. •HBXIP promotes the proliferation of breast cancer cell via upregulating PDGFB. -- Abstract: We have reported that the oncoprotein hepatitis B virus X-interacting protein (HBXIP) acts as a novel transcriptional coactivator to promote proliferation and migration of breast cancer cells. Previously, we showed that HBXIP was able to activate nuclear factor-?B (NF-?B) in breast cancer cells. As an oncogene, the platelet-derived growth factor beta polypeptide (PDGFB) plays crucial roles in carcinogenesis. In the present study, we found that both HBXIP and PDGFB were highly expressed in breast cancer cell lines. Interestingly, HBXIP was able to increase transcriptional activity of NF-?B through PDGFB, suggesting that HBXIP is associated with PDGFB in the cells. Moreover, HBXIP was able to upregulate PDGFB at the levels of mRNA, protein and promoter in the cells. Then, we identified that HBXIP stimulated the promoter of PDGFB through activating transcription factor Sp1. In function, HBXIP enhanced the proliferation of breast cancer cells through PDGFB in vitro. Thus, we conclude that HBXIP upregulates PDGFB via activating transcription factor Sp1 to promote proliferation of breast cancer cells.
Zhang, Yingyi; Zhao, Yu; Li, Leilei; Shen, Yu; Cai, Xiaoli [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China)] [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China); Zhang, Xiaodong, E-mail: [email protected] [Department of Cancer Research, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071 (China)] [Department of Cancer Research, Institute for Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071 (China); Ye, Lihong, E-mail: [email protected] [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China)] [Department of Biochemistry, College of Life Sciences, Nankai University, Tianjin 300071 (China)
2013-05-03
161
PubMed Central
Oncoprotein CIP2A a Cancerous Inhibitor of PP2A forms an “oncogenic nexus” by virtue of its control on PP2A and MYC stabilization in cancer cells. The expression and prognostic function of CIP2A in different solid tumors including colorectal carcinoma, head & neck cancers, gastric cancers, lung carcinoma, cholangiocarcinoma, esophageal cancers, pancreatic carcinoma, brain cancers, breast carcinoma, bladder cancers, ovarian carcinoma, renal cell carcinomas, tongue cancers, cervical carcinoma, prostate cancers, and oral carcinoma as well as a number of hematological malignancies are just beginning to emerge. Herein, we reviewed the recent progress in our understanding of (1) how an “oncogenic nexus” of CIP2A participates in the tumorigenic transformation of cells and (2) how we can prospect/view the clinical relevance of CIP2A in the context of cancer therapy. The review will try to understand the role of CIP2A (a) as a biomarker in cancers and evaluate the prognostic value of CIP2A in different cancers (b) as a therapeutic target in cancers and (c) in drug response and developing chemo-resistance in cancers. PMID:25015035
De, Pradip; Carlson, Jennifer; Leyland-Jones, Brian; Dey, Nandini
2014-01-01
162
SciTech Connect
Purpose: To analyze p53, bcl-2, c-myc, and cyclooxygenase-2 protein expression changes and examine their relationship with various antioxidant enzymes in esophageal carcinoma patients. Methods and Materials: Patients in Group 1 underwent transhiatal esophagectomy and those in Group 2 were administered chemoradiotherapy followed by surgery after 4 weeks of neoadjuvant therapy. Results: The relationship analysis among the various protein markers and antioxidant enzymes showed an inverse correlation between bcl-2 and superoxide dismutase/catalase in tumor tissues, irrespective of the treatment arm followed. An important positive association was observed between bcl-2 and reduced glutathione levels in the tumor tissue of patients receiving neoadjuvant therapy. Another apoptosis-modulating marker, c-myc, in the tumor tissue of Group 2 patients showed similar pattern levels (high and low) as that of superoxide dismutase/catalase. The association of cyclooxygenase-2 and p53 with various antioxidant enzymes showed a significant positive correlation between cyclooxygenase-2 expression and catalase activity and an inverse trend between p53 expression and superoxide dismutase and catalase activity in the tumor tissue of patients given neoadjuvant therapy. In addition, patients with overexpressed p53 protein levels had lower glutathione peroxidase enzyme levels and vice versa in the tumor tissue of patients who had undergone surgery as their main mode of treatment. Conclusion: The results of this study broaden the insight into the relationships shared among oncoproteins and the antioxidant defense system, and this could be helpful in the clinical management of esophageal carcinoma.
Kaur, Tranum [Department of Biophysics, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Gupta, Rajesh [Department of General Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Vaiphei, Kim [Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Kapoor, Rakesh [Department of Radiotherapy, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Gupta, N.M. [Department of General Surgery, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Khanduja, K.L. [Department of Biophysics, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Department of Biophysics, Postgraduate Institute of Medical Education and Research, Chandigarh (India)], E-mail: [email protected]
2008-02-01
163
PubMed Central
Acute Promyelocytic Leukemia (APL) results from a reciprocal translocation that fuses the gene for the PML tumor suppressor to that encoding the retinoic acid receptor alpha (RAR?). The resulting PML-RAR? oncogene product interferes with multiple regulatory pathways associated with myeloid differentiation, including normal PML and RAR? functions. The standard treatment for APL includes anthracycline-based chemotherapeutic agents plus the RAR? agonist all-trans retinoic acid (ATRA). Relapse, which is often accompanied by ATRA resistance, occurs in an appreciable frequency of treated patients. One potential mechanism suggested by model experiments featuring the selection of ATRA resistant APL cell lines involves ATRA resistant versions of the PML-RAR? oncogene, where the relevant mutations localize to the RAR? ligand-binding domain (LBD). Such mutations may act by compromising agonist binding, but other mechanisms are possible. Here, we studied the molecular consequence of ATRA resistance by use of circular dichroism, protease resistance, and fluorescence anisotropy assays employing peptides derived from the NCOR nuclear co-repressor and the ACTR nuclear co-activator. The consequences of the mutations on global structure and co-factor interaction functions were assessed quantitatively, providing insights into the basis of agonist resistance. Attenuated co-factor switching and increased protease resistance represent features of the LBDs of ATRA-resistant PML-RAR?, and these properties may be recapitulated in the full-length oncoproteins. PMID:22228505
Farris, Mindy; Lague, Astrid; Manuelyan, Zara; Statnekov, Jacob; Francklyn, Christopher
2011-01-01
164
PubMed Central
Cottontail rabbit papillomavirus induces on cottontail and domestic rabbits papillomas which progress at a high frequency to carcinoma. The virus encodes three transforming proteins; one is translated from open reading frame (ORF) E7 and binds the retinoblastoma protein, and two, LE6 and SE6, are translated from the first and second ATGs of ORF E6, respectively. Here we show that neither of the E6 proteins coprecipitated with p53 in vitro, nor did they bind to a recently identified E6-binding protein (J. J. Chen, C. E. Reid, V. Band, and E. Androphy, Science 269:529-531, 1995). This protein was shown to bind to the E6 proteins of the high-risk human papillomairus types 16 and 18 but not to the low-risk human papillomavirus types VI and II. In-frame deletions cloned into the pZipNeo vector were used to identify structural features of SE6 and LE6 important for transformation of NIH 3T3 cells. Three deletions covering the amino-terminal half of SE6 did not transform cells. In two of the three deletions, two Cys-X-X-Cys motifs were deleted, each deletion preventing the formation of one of the potential small Zn fingers of SE6. Among the LE6 deletions, only one had a reduced transformation efficiency, while seven transformed cells at least as efficiently as wild-type LE6. In each of three of these seven mutants, two Cys-X-X-Cys motifs were deleted. None of the three amino acid deletions which abolished transformation by SE6 reduced transformation by LE6. Furthermore, transformation did not correlate with the level of SE6 or LE6 proteins detectable. ORF E8 colinear with ORF E6, which could generate a 50-amino-acid protein with a hydrophobic segment, did not transform cells when cloned into the pZipNeo vector. However, mutation of the E8 ATG, which did not alter the amino acid sequence of LE6, increased transformation by LE6 without affecting the level of LE6 expression. The data suggest that transformation by the E6 proteins is not mediated by interfering with p53 function or through binding to the E6-binding protein. Furthermore, different structural features are important to maintain transformation functions and protein stability of LE6 and SE6. Finally, E8 seems not to be a transforming protein but rather appears to modulate transformation bv LE6. PMID:8648665
Harry, J B; Wettstein, F O
1996-01-01
165
PubMed Central
The saimiri transforming protein (STP) oncogene of Herpesvirus saimiri subgroup A strain 11 (STP-A11) is not required for viral replication but is required for lymphoid cell immortalization in culture and lymphoma induction in primates. We previously showed that STP-A11 interacts with cellular Src kinase through its SH2 binding motif and that this interaction elicits Src signal transduction. Here we demonstrate that STP-A11 interacts with signal transducer and activator of transcription 3 (Stat3) independently of Src association and that the amino-terminal short proline-rich motif of STP-A11 and the central linker region of Stat3 are necessary for their interaction. STP-A11 formed a triple complex with Src kinase and Stat3 where Src kinase phosphorylated Stat3, resulting in the nuclear localization and transcriptional activation of Stat3. Consequently, the constitutively active Stat3 induced by STP-A11 elicited cellular signal transduction, which ultimately induced cell survival and proliferation upon serum deprivation. Furthermore, this activity was strongly correlated with the induction of Fos, cyclin D1, and Bcl-XL expression. These results demonstrate that STP-A11 independently targets two important cellular signaling molecules, Src and Stat3, and that these proteins cooperate efficiently to induce STP-A11-mediated transformation. PMID:15163742
Chung, Young-Hwa; Cho, Nam-hyuk; Garcia, Maria Ines; Lee, Sun-Hwa; Feng, Pinghui; Jung, Jae U.
2004-01-01
166
PubMed
The study of the small DNA tumor viruses continues to provide valuable new insights into oncogenesis and fundamental biological processes. Although much has already been revealed about how the human papillomaviruses (HPVs) can transform cells and contribute to cervical and oropharyngeal cancer, there clearly is much more to learn. In this issue of Oncogene, Pang et al., doi:10.1038/onc.2013.426, demonstrate that the high-risk HPV16 E7 oncogene can promote cellular proliferation by interacting with the DREAM (DP, RB-like, E2F and MuvB) complex at two distinct phases of the cell cycle. Consistent with earlier work, HPV16 E7 can bind to the retinoblastoma tumor suppressor (RB) family member p130 (RBL2) protein and promote its proteasome-mediated destruction thereby disrupting the DREAM complex and can prevent exit from the cell cycle into quiescence. In addition, they demonstrate that HPV16 E7 can bind to MuvB core complex in association with BMYB and FOXM1 and activate gene expression during the G2 and M phase of the cell cycle. Thus, HPV16 E7 acts to prevent exit from the cell cycle entry and promotes mitotic proliferation and may account for the high levels of FOXM1 often observed in poor-risk cervical cancers. PMID:24166507
DeCaprio, J A
2014-07-31
167
E-print Network
-743-72-6011; fax: +81-743-72-6019. E-mail address: [email protected] (Y. Kanemitsu) can be implanted. PII: S 1386-9477(99)00333-1 #12;Y. Kanemitsu et al. / Physica E 7 (2000) 322Â325 323 Fig. 1
Atwater, Harry
168
PubMed Central
Previous studies have shown that wild-type human telomerase reverse transcriptase (hTERT) protein can functionally replace the human papillomavirus type 16 (HPV-16) E6 protein, which cooperates with the viral E7 protein in the immortalization of primary keratinocytes. In the current study, we made the surprising finding that catalytically inactive hTERT (hTERT-D868A), elongation-defective hTERT (hTERT-HA), and telomere recruitment-defective hTERT (hTERT N+T) also cooperate with E7 in mediating bypass of the senescence blockade and effecting cell immortalization. This suggests that hTERT has activities independent of its telomere maintenance functions that mediate transit across this restriction point. Since hTERT has been shown to have a role in gene activation, we performed microarray studies and discovered that E6, hTERT and mutant hTERT proteins altered the expression of highly overlapping sets of cellular genes. Most important, the E6 and hTERT proteins induced mRNA and protein levels of Bmi1, the core subunit of the Polycomb Group (PcG) complex 1. We show further that Bmi1 substitutes for E6 or hTERT in cell immortalization. Finally, tissue array studies demonstrated that expression of Bmi1 increased with the severity of cervical dysplasia, suggesting a potential role in the progression of cervical cancer. Together, these data demonstrate that hTERT has extra-telomeric activities that facilitate cell immortalization and that its induction of Bmi1 is one potential mechanism for mediating this activity. PMID:23592995
Miller, Jonathan; Dakic, Aleksandra; Chen, Renxiang; Palechor-Ceron, Nancy; Dai, Yuhai; Kallakury, Bhaskar; Schlegel, Richard; Liu, Xuefeng
2013-01-01
169
SciTech Connect
Highlights: ? We tried to identify targets of synovial sarcoma (SS)-associated SYT–SSX fusion gene. ? We established pluripotent stem cell (PSC) lines with inducible SYT–SSX gene. ? SYT–SSX responsive genes were identified by the induction of SYT–SSX in PSC. ? SS-related genes were selected from database by in silico analyses. ? 51 genes were finally identified among SS-related genes as targets of SYT–SSX in PSC. -- Abstract: Synovial sarcoma (SS) is a malignant soft tissue tumor harboring chromosomal translocation t(X; 18)(p11.2; q11.2), which produces SS-specific fusion gene, SYT–SSX. Although precise function of SYT–SSX remains to be investigated, accumulating evidences suggest its role in gene regulation via epigenetic mechanisms, and the product of SYT–SSX target genes may serve as biomarkers of SS. Lack of knowledge about the cell-of-origin of SS, however, has placed obstacle in the way of target identification. Here we report a novel approach to identify SYT–SSX2 target genes using human pluripotent stem cells (hPSCs) containing a doxycycline-inducible SYT–SSX2 gene. SYT–SSX2 was efficiently induced both at mRNA and protein levels within three hours after doxycycline administration, while no morphological change of hPSCs was observed until 24 h. Serial microarray analyses identified genes of which the expression level changed more than twofold within 24 h. Surprisingly, the majority (297/312, 95.2%) were up-regulated genes and a result inconsistent with the current concept of SYT–SSX as a transcriptional repressor. Comparing these genes with SS-related genes which were selected by a series of in silico analyses, 49 and 2 genes were finally identified as candidates of up- and down-regulated target of SYT–SSX, respectively. Association of these genes with SYT–SSX in SS cells was confirmed by knockdown experiments. Expression profiles of SS-related genes in hPSCs and human mesenchymal stem cells (hMSCs) were strikingly different in response to the induction of SYT–SSX, and more than half of SYT–SSX target genes in hPSCs were not induced in hMSCs. These results suggest the importance of cellular context for correct understanding of SYT–SSX function, and demonstrated how our new system will help to overcome this issue.
Hayakawa, Kazuo [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan) [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ikeya, Makoto [Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan)] [Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Fukuta, Makoto [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan) [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Woltjen, Knut [Department of Reprogramming Sciences, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan)] [Department of Reprogramming Sciences, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Tamaki, Sakura; Takahara, Naoko; Kato, Tomohisa; Sato, Shingo [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan)] [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Otsuka, Takanobu [Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan)] [Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Toguchida, Junya, E-mail: [email protected] [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan) [Department of Tissue Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto (Japan); Department of Cell Growth and Differentiation, Center for iPS Cell Research and Application, Kyoto University, Kyoto (Japan); Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto (Japan)
2013-03-22
170
PubMed
The nematic liquid crystalline mixture E7 was confined with similar filling degrees to molecular sieves with constant composition but different pore diameters (from 2.8 to 6.8 nm). Fourier transform infrared analysis proved that the E7 molecules interact via the cyanogroup with the pore walls of the molecular sieves. The molecular dynamics of the system was investigated by broadband dielectric spectroscopy (10(-2)-10(9) Hz) covering a wide temperature range of approximately 200 K from temperatures well above the isotropic-nematic transition down to the glass transition of bulk E7. A variety of relaxation processes is observed including two modes that are located close to the bulk behavior in its temperature dependence. For all confined samples, two relaxation processes, at frequencies lower than the processes observed for the bulk, were detected. At lower temperatures, their relaxation rates have different temperature dependencies whereas at higher temperatures, they seem to collapse into one chart. The temperature dependence of the slowest process (S-process) obeys the Vogel-Fulcher-Tammann law indicating a glassy dynamics of the E7 molecules anchored to the pore surface. The pore size dependence of both the Vogel temperature and fragility revealed a steplike transition around 4 nm pore size, which indicates a transition from a strong to a fragile behavior. The process with a relaxation rate in between the bulklike and the S-process (I-process) shows no dependence on the pore size. The agreement of the I-process with the behavior of a 5CB surface layer adsorbed on nonporous silica leads to the assignment of E7 molecules anchored at the outer surface of the microcrystals of the molecular sieves. PMID:20550409
Brás, A R; Frunza, S; Guerreiro, L; Fonseca, I M; Corma, A; Frunza, L; Dionísio, M; Schönhals, A
2010-06-14
171
PubMed Central
FLT3 is the most frequently mutated kinase in acute myeloid leukemia (AML). Internal tandem duplications (ITDs) in the juxta-membrane region constitute the majority of activating FLT3 mutations. Several FLT3 kinase inhibitors were developed and tested in the clinic with significant success. However, recent studies have reported the development of secondary drug resistance in patients treated with FLT3 inhibitors. Since FLT3-ITD is an HSP90 client kinase, we here explored if targeting the stability of drug-resistant FLT3 mutant protein could be a potential therapeutic option. We observed that HSP90 inhibitor treatment resulted in the degradation of inhibitor-resistant FLT3-ITD mutants and selectively induced toxicity in cells expressing FLT3-ITD mutants. Thus, HSP90 inhibitors provide a potential therapeutic choice to overcome secondary drug resistance following TKI treatment in FLT3-ITD positive AML. PMID:24849514
Duyster, Justus
2014-01-01
172
PubMed
Human papillomavirus (HPV) DNA integrations may affect therapeutic responses in cancers through ATM network-related DNA damage response (DDR). We studied whether cisplatin-induced DDR was altered in human HK-2 renal tubular cells immortalized by HPV16 E6/E7 genes. Cytotoxicity assays utilized thiazolyl blue dye and DDR was identified by gene expression differences, double-strand DNA breaks, ATM promoter activity, and analysis of cell cycling and side population cells. After cisplatin, HK-2 cells showed greater ATM promoter activity indicating activation of this network, but DDR was muted, since little ?H2AX was expressed, DNA strand breaks were absent and cells continued cycling. When HK-2 cells were treated with the MDM2 antagonist inducing p53, nutlin-3, or p53 transcriptional activator, tenovin-1, cell growth decreased but cisplatin toxicity was unaffected. By contrast, arsenic trioxide, which by inhibiting wild-type p53-induced phosphatase-1 that serves responses downstream of p53, and by depolymerizing tubulin, synergistically enhanced cisplatin cytotoxicity including loss of SP cells. Our findings demonstrated that HPV16 E6/E7 altered DDR through p53-mediated cell growth controls, which may be overcome by targeting of WIP1 and other processes, and thus should be relevant for treating renal cell carcinoma. PMID:25444910
Dogra, Samriti; Bandi, Sriram; Viswanathan, Preeti; Gupta, Sanjeev
2015-01-28
173
PubMed
We have reported that the oncoprotein hepatitis B X-interacting protein (HBXIP) plays a crucial role in the promotion of migration of breast cancer cells. Lamellipodia and filopodia protrusions play fundamental roles, involving dynamic cytoskeleton reorganization in the metastasis of cancer. Here, we observed that the expression levels of both HBXIP and Calpain small subunit 1 (Capn4) were very high in clinical metastatic lymph nodes of breast tumor. Then, we found that HBXIP was able to up-regulate Capn4 at the levels of promoter, mRNA and protein in breast cancer cells through activation of ERK1/2. Moreover, we showed that HBXIP activated ERK1/2 through up-regulating MEKK2. In function, we revealed that HBXIP increased the filopodia formation through Capn4, resulting in cell migration. Thus, we conclude that the oncoprotein HBXIP enhances the migration of breast cancer through increasing filopodia formation involving MEKK2/ERK1/2/Capn4 signaling. Therapeutically, HBXIP may serve as a novel target in breast cancer. PMID:25304384
Li, Yinghui; Zhang, Zhao; Zhou, Xiaolei; Li, Leilei; Liu, Qian; Wang, Zhen; Bai, Xiao; Zhao, Yu; Shi, Hui; Zhang, Xiaodong; Ye, Lihong
2014-12-28
174
PubMed Central
We describe molecular and clinical findings in an immunocompetent patient with an oligoastrocytoma and the concomitant presence of the human papovavirus, JC virus (JCV), which is the etiologic agent of the subacute, debilitating demyelinating disease, progressive multifocal leukoencephalopathy. Histologic review revealed a glial neoplasm consisting primarily of a moderately cellular oligodendroglioma with distinct areas of a fibrillary astrocytoma. Immunohistochemical analysis revealed nuclear staining of tumor cells with antibodies against the viral oncoprotein [tumor antigen (T antigen)], the proliferation marker (Ki67), and the cellular proliferation regulator (p53). Using primers specific to the JCV control region, PCR yielded amplified DNA that was identical to the control region of the Mad-4 strain of the virus. PCR analysis demonstrated the presence of the genome for the viral oncoprotein, T antigen, and results from primer extension studies revealed synthesis of the viral early RNA for T antigen in the tumor tissues. The presence of viral T antigen in the tumor tissue was further demonstrated by immunoblot assay. To our knowledge, this is the first report of the presence of JCV DNA, RNA, and T antigen in tissue in which viral T antigen is localized to tumor cell nuclei and suggests the possible association of JCV with some glial neoplasms. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8692997
Rencic, A; Gordon, J; Otte, J; Curtis, M; Kovatich, A; Zoltick, P; Khalili, K; Andrews, D
1996-01-01
175
PubMed
Basic helix-loop-helix (bHLH) transcription factor Twist is one of the key inducers of epithelial to mesenchymal transition (EMT) that is a transdifferentiation program associated with embryo development and tumor metastasis. High level of Twist expression is shown to be correlated with cancer malignancy. Although Twist has been reported to be degraded by F-box and leucine-rich repeat protein 14 (FBXL14), the molecular mechanisms by which Twist levels are regulated have not been fully elucidated. In the present study, we identified Twist to be a ubiquitin substrate of ?-transducin repeat-containing protein (?-TRCP), the adaptor subunit of SCF(?-TRCP) (Skp1-Cul1-F-box protein) E3 ligase complex. We observed that depletion of ?-TRCP leads to an accumulation of Twist protein, which could enhance tumor cell motility and cancer metastasis. Moreover, phosphorylation of Twist by inhibitor of KappaB kinase ? (IKK?) at multiple sites triggers its cytoplasmic translocation and the destruction by SCF(?-TRCP). Thus, our results provide the potential molecular mechanism of how the mesenchymal marker Twist is degraded, thereby shedding lights into regulation of the EMT, and providing the rationale for development of new therapeutic intervention to achieve better treatment outcomes in human cancer. PMID:23375009
Zhong, Jiateng; Ogura, Kohei; Wang, Zhiwei; Inuzuka, Hiroyuki
2013-01-01
176
PubMed
The oncogenic fusion gene EWS-WT1 is the defining chromosomal translocation in desmoplastic small round-cell tumors (DSRCT), a rare but aggressive soft tissue sarcoma with a high rate of mortality. EWS-WT1 functions as an aberrant transcription factor that drives tumorigenesis, but the mechanistic basis for its pathogenic activity is not well understood. To address this question, we created a transgenic mouse strain that permits physiologic expression of EWS-WT1 under the native murine Ews promoter. EWS-WT1 expression led to a dramatic induction of many neuronal genes in embryonic fibroblasts and primary DSRCT, most notably the neural reprogramming factor ASCL1. Mechanistic analyses demonstrated that EWS-WT1 directly bound the proximal promoter of ASCL1, activating its transcription through multiple WT1-responsive elements. Conversely, EWS-WT1 silencing in DSRCT cells reduced ASCL1 expression and cell viability. Notably, exposure of DSRCT cells to neuronal induction media increased neural gene expression and induced neurite-like projections, both of which were abrogated by silencing EWS-WT1. Taken together, our findings reveal that EWS-WT1 can activate neural gene expression and direct partial neural differentiation via ASCL1, suggesting agents that promote neural differentiation might offer a novel therapeutic approach to treat DSRCT. PMID:24934812
Kang, Hong-Jun; Park, Jun Hong; Chen, WeiPing; Kang, Soo Im; Moroz, Krzysztof; Ladanyi, Marc; Lee, Sean Bong
2014-08-15
177
PubMed
The expression of high-risk human papillomavirus E6 and E7 proteins in most cervical tumors raised a considerable interest in the diagnostic and therapeutic applications of functional oligonucleotides (i.e., DNAzymes, ribozymes, and aptamers) directed against HPV targets. Aptamers are short single-stranded oligonucleotides that specifically recognize a wide variety of molecular targets, including HPV proteins. Here, we describe a protocol for the successful isolation of RNA aptamers directed at the recombinant HPV-16 E7 protein through the application of the SELEX method. Once the nucleic acid sequence of a functional aptamer is determined, large amounts of the oligonucleotide can be produced and modified at low cost and high efficiency. The remarkable affinity and specificity of aptamers for their targets make these molecules the next-generation tool for diagnostics and therapeutics of cervical cancer. PMID:25348310
Toscano-Garibay, Julia Dolores; Benítez-Hess, María Luisa; Alvarez-Salas, Luis Marat
2015-01-01
178
PubMed Central
The expression of ?E?7 integrin has been related to the selective retention of lymphocytes in mucosal tissues of gut, urogenital tract and lung. To identify potential disease-associated ?E?7 expression patterns on cells accounting for lymphocytic alveolitis in interstitial lung disease (ILD), ?E expression on CD4+ and CD8+ T cell subsets was evaluated by dual-colour flow cytometry in peripheral blood and bronchoalveolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF; n = 18), hypersensitivity pneumonitis (HP; n = 20) and sarcoidosis (n = 44) in comparison with healthy controls (n = 15). In both healthy individuals and all patient groups the proportion of ?E-bearing T cells in peripheral blood was < 2%, whereas the vast majority of alveolar CD8+ T cells consistently co-expressed ?E. Absolute alveolar CD8+?E+ cell numbers/ml were up to 30-fold increased in HP patients. Proportions of ?E-bearing CD4+ cells in BALF were significantly elevated in IPF (74.0 ± 2.7%) and HP (70.0 ± 2.4%) compared with normals (30.0 ± 1.8%) (mean ± s.e.m.; P < 0.01). In sarcoidosis, the ?E expression on BALF CD4+ cells displayed subgroup dependency: proportions significantly lower than normal were noted in chest radiographic stage I (14.3 ± 1.5%), but increased proportions in stages II (50.0 ± 3.8%) and III (64.0 ± 4.8%). Correlations between common markers of T cell activation or BALF transforming growth factor-beta (TGF-?) bioactivity and ?E expression were not noted. We conclude that the vast majority of alveolar CD8+ T cells consistently express ?E?7 and that distinct patterns of ?E?7 expression on alveolar CD4+ lymphocytes in sarcoidosis are related to the diverse manifestations of the sarcoid inflammatory process in the lung. PMID:10337028
Lohmeyer, J; Friedrich, J; Grimminger, F; Maus, U; Tenter, R; Morr, H; Velcovsky, H G; Seeger, W; Rosseau, S
1999-01-01
179
PubMed
Approximately half of poor prognosis neuroblastomas (NBs) are characterized by pathognomonic MYCN gene amplification and MYCN over-expression. Here we present data showing that short-interfering RNA mediated depletion of the protein arginine methyltransferase 5 (PRMT5) in cell-lines representative of NBs with MYCN gene amplification leads to greatly impaired growth and apoptosis. Growth suppression is not apparent in the MYCN-negative SH-SY5Y NB cell-line, or in two immortalized human fibroblast cell-lines. Immunoblotting of NB cell-lines shows that high PRMT5 expression is strongly associated with MYCN-amplification (P < 0.004, Mann-Whitney U-test) and immunohistochemical analysis of primary NBs reveals that whilst PRMT5 protein is ubiquitously expressed in the cytoplasm of most cells, MYCN-amplified tumours exhibit pronounced nuclear PRMT5 staining. PRMT5 knockdown in MYCN-overexpressing cells, including the SHEP-21N cell-line with inducible MYCN expression leads to a dramatic decrease in MYCN protein and MYCN-associated cell-death in SHEP-21N cells. Quantitative gene expression analysis and cycloheximide chase experiments suggest that PRMT5 regulates MYCN at a post-transcriptional level. Reciprocal co-immunoprecipitation experiments demonstrated that endogenous PRMT5 and MYCN interact in both SK-N-BE(2)C and NGP cell lines. By using liquid chromatography - tandem mass spectrometry (LC-MS/MS) analysis of immunoprecipitated MYCN protein, we identified several potential sites of arginine dimethylation on the MYCN protein. Together our studies implicate PRMT5 in a novel mode of MYCN post-translational regulation and suggest PRMT5 plays a major role in NB tumorigenesis. Small-molecule inhibitors of PRMT5 may therefore represent a novel therapeutic strategy for neuroblastoma and other cancers driven by the MYCN oncogene. PMID:25475372
Park, Ji Hyun; Szemes, Marianna; Vieira, Gabriella Cunha; Melegh, Zsombor; Malik, Sally; Heesom, Kate J; Von Wallwitz-Freitas, Laura; Greenhough, Alexander; Brown, Keith W; Zheng, Y George; Catchpoole, Daniel; Deery, Michael J; Malik, Karim
2014-11-15
180
PubMed
Our goal in this work was to illustrate the Epstein-Barr virus (EBV)-modulated global biochemical profile and provide a novel metabolism-related target to improve the therapeutic regimen of nasopharyngeal carcinoma (NPC). We used a metabolomics approach to investigate EBV-modulated metabolic changes, and found that the exogenous overexpression of the EBV-encoded latent membrane protein 1 (LMP1) significantly increased glycolysis. The deregulation of several glycolytic genes, including hexokinase 2 (HK2), was determined to be responsible for the reprogramming of LMP1-mediated glucose metabolism in NPC cells. The upregulation of HK2 elevated aerobic glycolysis and facilitated proliferation by blocking apoptosis. More importantly, HK2 was positively correlated with LMP1 in NPC biopsies, and high HK2 levels were significantly associated with poor overall survival of NPC patients following radiation therapy. Knockdown of HK2 effectively enhanced the sensitivity of LMP1-overexpressing NPC cells to irradiation. Finally, c-Myc was demonstrated to be required for LMP1-induced upregulation of HK2. The LMP1-mediated attenuation of the PI3-K/Akt-GSK3beta-FBW7 signaling axis resulted in the stabilization of c-Myc. These findings indicate a close relationship between EBV and glycolysis in NPC. Notably, LMP1 is the key regulator of the reprogramming of EBV-mediated glycolysis in NPC cells. Given the importance of EBV-mediated deregulation of glycolysis, anti-glycolytic therapy might represent a worthwhile avenue of exploration in the treatment of EBV-related cancers. PMID:24662831
Xiao, L; Hu, Z-Y; Dong, X; Tan, Z; Li, W; Tang, M; Chen, L; Yang, L; Tao, Y; Jiang, Y; Li, J; Yi, B; Li, B; Fan, S; You, S; Deng, X; Hu, F; Feng, L; Bode, A M; Dong, Z; Sun, L-Q; Cao, Y
2014-09-11
181
SciTech Connect
Purpose: Patients with oropharyngeal squamous cell carcinoma (OSCC) whose disease is associated with high-risk human papillomavirus (HPV) infection have a significantly better outcome than those with HPV-negative disease, but the reasons for the better outcome are not known. We postulated that they might relate to an ability of HPV proteins to confer a better response to radiotherapy, a commonly used treatment for OSCC. Methods and Materials: We stably expressed the specific splicing-derived isoforms, E6*I and E6*II, or the entire E6 open reading frame (E6total), which gives rise to both full length and E6*I isoforms, in OSCC cell lines. Radiation resistance was measured in clonogenicity assays, p53 activity was measured using transfected reporter genes, and flow cytometry was used to analyze cell cycle and apoptosis. Results: E6*I and E6total sensitized the OSCC cells to irradiation, E6*I giving the greatest degree of radiosensitization (approximately eightfold lower surviving cell fraction at 10 Gy), whereas E6*II had no effect. In contrast to radiosensitivity, E6*I was a weaker inhibitor than E6total of tumor suppressor p53 transactivator activity in the same cells. Flow cytometric analyses showed that irradiated E6*I expressing cells had a much higher G2M:G1 ratio than control cells, indicating that, after G2, cells were diverted from the cell cycle to programmed cell death. Conclusion: This study supports a role for E6*I in the enhanced responsiveness of HPV-positive oropharyngeal carcinomas to p53-independent radiation-induced death.
Pang, Ervinna [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Infectious Diseases and Immunology, University of Sydney, NSW (Australia); Delic, Naomi C. [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Dermatology, University of Sydney, NSW (Australia); Hong, Angela; Zhang Mei [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Department of Radiation Oncology, Royal Prince Alfred Hospital, NSW (Australia); Rose, Barbara R. [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Infectious Diseases and Immunology, University of Sydney, NSW (Australia); Lyons, J. Guy, E-mail: [email protected] [Sydney Head and Neck Cancer Institute, Sydney Cancer Centre, Royal Prince Alfred Hospital, NSW (Australia); Discipline of Dermatology, University of Sydney, NSW (Australia)
2011-03-01
182
E-print Network
Lack of the canonical pRB-binding domain in the E7 ORF of artiodactyl papillomaviruses of papillomavirus (PV) E7 proteins has been implicated in the immortalization and transformation of the host cell. However, sequencing of the complete genomes of bovine papillomavirus type 3 (BPV-3), bovine papillomavirus
DeSalle, Rob
183
PubMed
The activity of the kinase domain of the oncoprotein v-Fps was found to be sensitive to the concentration of magnesium ions. Plots of initial velocity versus free magnesium concentration are hyperbolic and do not extrapolate to the origin at stoichiometric ATP-Mg, indicating that there are two sites for metal chelation on the enzyme and the second is nonessential for catalysis. The second metal is strongly activating and increases the reaction rate constant almost 20-fold from 0.5 to 8.3 s-1 using 0.2 mM ATP-Mg and 1 mM peptide, EAEIYEAIE. This increase in rate is due to a large increase in the apparent affinity of ATP-Mg at high magnesium concentrations. At 0.5 and 10 mM free Mg2+, KATP-Mg is 3.6 and 0.22 mM, respectively. Extrapolation of the observed affinity of ATP-Mg to zero and infinite free metal indicates that KATP-Mg is greater than 8 mM in the absence of the second metal and 0.1 mM in the presence of the second metal, a minimum 80-fold enhancement. By comparison, free levels of the divalent ion do not influence maximum turnover (kcat) and have only a 2-fold effect on the Km for the peptide substrate between 0.5 and 20 mM free Mg2+. Viscosometric studies indicate that free Mg2+ does not influence the rates of phosphoryl transfer or net product release above 0.5 mM but does affect directly the dissociation constant for ATP-Mg. The Kd for ATP-Mg in the absence and presence of the second metal ion is >32 and 0.4 mM, respectively. At high magnesium concentrations, ATP-Mg and the peptide substrate bind independently, while at lower concentrations (0.5 mM), there is significant negative binding synergism suggesting that the second metal may help to reduce charge repulsion between ATP-Mg and the peptide. The data indicate that the first metal is sufficient for phosphoryl transfer. While the second metal could have some influence on phosphoryl transfer or product binding, it is a potent activator that functions minimally by controlling ATP-Mg binding. PMID:9730835
Saylor, P; Wang, C; Hirai, T J; Adams, J A
1998-09-01
184
SciTech Connect
Highlights: Black-Right-Pointing-Pointer H-bonding network loop by PheB10Tyr mutation is proposed. Black-Right-Pointing-Pointer The propionate group H-bonding network restricted the flexibility of the heme. Black-Right-Pointing-Pointer The hydrogen bonding interaction modulates the electron density of the iron. Black-Right-Pointing-Pointer Propionate H-bonding network loop explains the heme-ligand stabilization. -- Abstract: Propionates, as peripheral groups of the heme active center in hemeproteins have been described to contribute in the modulation of heme reactivity and ligand selection. These electronic characteristics prompted the question of whether the presence of hydrogen bonding networks between propionates and distal amino acids present in the heme ligand moiety can modulate physiological relevant events, like ligand binding association and dissociation activities. Here, the role of these networks was evaluated by NMR spectroscopy using the hemoglobin I PheB10Tyr mutant from Lucina pectinata as model for TyrB10 and GlnE7 hemeproteins. {sup 1}H-NMR results for the rHbICN PheB10Tyr derivative showed chemical shifts of TyrB10 OH{eta} at 31.00 ppm, GlnE7 N{sub {epsilon}1}H/N{sub {epsilon}2}H at 10.66 ppm/-3.27 ppm, and PheE11 C{sub {delta}}H at 11.75 ppm, indicating the presence of a crowded, collapsed, and constrained distal pocket. Strong dipolar contacts and inter-residues crosspeaks between GlnE7/6-propionate group, GlnE7/TyrB10 and TyrB10/CN suggest that this hydrogen bonding network loop between GlnE7, TyrB10, 6-propionate group, and the heme ligand contribute significantly to the modulation of the heme iron electron density as well as the ligand stabilization mechanism. Therefore, the network loop presented here support the fact that the electron withdrawing character of the hydrogen bonding is controlled by the interaction of the propionates and the nearby electronic environments contributing to the modulation of the heme electron density state. Thus, we hypothesize that in hemeproteins with similar electrostatic environment the flexibility of the heme-6-propionate promotes a hydrogen bonding network loop between the 6-propionate, the heme ligand and nearby amino acids, tailoring in this way the electron density in the heme-ligand moiety.
Ramos-Santana, Brenda J., E-mail: [email protected] [Department of Chemistry, University of Puerto Rico, Mayagueez Campus, P.O. Box 9019, Mayagueez 00681-9019 (Puerto Rico); Lopez-Garriga, Juan, E-mail: [email protected] [Department of Chemistry, University of Puerto Rico, Mayagueez Campus, P.O. Box 9019, Mayagueez 00681-9019 (Puerto Rico)] [Department of Chemistry, University of Puerto Rico, Mayagueez Campus, P.O. Box 9019, Mayagueez 00681-9019 (Puerto Rico)
2012-08-10
185
PubMed
Accumulating evidence supports the concept that cancer stem cells (CSCs) are responsible for the tumor recurrence and metastasis, the two major causes of cancer-related death. Therefore, CSC-targeted cancer therapy is important for the future development of more effective and advanced cancer therapy. One of the approaches is to specifically silence oncogene expression in CSCs and inhibit their growth. The significance of this approach is its specificity and ability to avoid multi-drug resistance of CSCs. In this chapter, we will describe a method of silencing HPV oncogenes E6/E7 in human cervical CSCs using HeLa cells as a model system. PMID:25348305
Gu, Wenyi; McMillan, Nigel; Yu, Chengzhong
2015-01-01
186
NASA Technical Reports Server (NTRS)
The generalized simulation model developed for the E-7A STOVL fighter-type aircraft configuration has attempted to define the limits of acceptibility for a vertical-to-horizontal-to-vertical flight transition envelope. An effort was also made to determine the control power required during hover and transition, and to evaluate whether the integration of flight and propulsion controls thus far effected achieves good flying qualities throughout the low-speed flight envelope. The results thus obtained furnish a general view of the acceptable transition corridor, expressed in terms of the minimum-climb capability.
Franklin, James A.; Stortz, Michael W.; Gerdes, Ronald M.; Hardy, Gordon H.; Martin, James L.; Engelland, Shawn A.
1988-01-01
187
PubMed
Herpesvirus saimiri group C strains are capable of transforming human and simian T-lymphocyte populations to permanent antigen-independent growth. Two viral oncoproteins, StpC and Tip, that are encoded by a single bicistronic mRNA, act in concert to mediate this phenotype. A closely related New World monkey herpesvirus, herpesvirus ateles, transcribes a single spliced mRNA at an equivalent genome locus. The encoded protein, Tio, has sequence homologies to both StpC and Tip. We inserted the tio sequence of herpesvirus ateles strain 73 into a recombinant herpesvirus saimiri C488 lacking its own stpC/tip oncogene. Simian as well as human T lymphocytes were growth transformed by the chimeric Tio-expressing viruses. Thus, a single herpesvirus protein appears to be responsible for the oncogenic effects of herpesvirus ateles. PMID:15331715
Albrecht, Jens-Christian; Biesinger, Brigitte; Müller-Fleckenstein, Ingrid; Lengenfelder, Doris; Schmidt, Monika; Fleckenstein, Bernhard; Ensser, Armin
2004-09-01
188
PubMed Central
Herpesvirus saimiri group C strains are capable of transforming human and simian T-lymphocyte populations to permanent antigen-independent growth. Two viral oncoproteins, StpC and Tip, that are encoded by a single bicistronic mRNA, act in concert to mediate this phenotype. A closely related New World monkey herpesvirus, herpesvirus ateles, transcribes a single spliced mRNA at an equivalent genome locus. The encoded protein, Tio, has sequence homologies to both StpC and Tip. We inserted the tio sequence of herpesvirus ateles strain 73 into a recombinant herpesvirus saimiri C488 lacking its own stpC/tip oncogene. Simian as well as human T lymphocytes were growth transformed by the chimeric Tio-expressing viruses. Thus, a single herpesvirus protein appears to be responsible for the oncogenic effects of herpesvirus ateles. PMID:15331715
Albrecht, Jens-Christian; Biesinger, Brigitte; Müller-Fleckenstein, Ingrid; Lengenfelder, Doris; Schmidt, Monika; Fleckenstein, Bernhard; Ensser, Armin
2004-01-01
189
PubMed Central
B-cell chronic lymphocytic leukemia (CLL), an incurable leukemia, is characterized by defective apoptosis. We found that the SET oncoprotein, a potent inhibitor of the protein phosphatase 2A (PP2A) tumor suppressor, is overexpressed in primary CLL cells and B-cell non-Hodgkin lymphoma (NHL) cell line cells. In CLL, increased levels of SET correlated significantly with disease severity (shorter time to treatment and overall survival). We developed SET antagonist peptides that bound SET, increased cellular PP2A activity, decreased Mcl-1 expression, and displayed selective cytotoxicity for CLL and NHL cells in vitro. In addition, shRNA for SET was cytotoxic for NHL cells in vitro. The SET antagonist peptide COG449 inhibited growth of NHL tumor xenografts in mice. These data demonstrate that SET is a new treatment target in B-cell malignancies and that SET antagonists represent novel agents for treatment of CLL and NHL. PMID:21844565
Chen, Youwei; Oddo, Jessica; Matta, Karen M.; Neil, Jessica; Davis, Evan D.; Volkheimer, Alicia D.; Lanasa, Mark C.; Friedman, Daphne R.; Goodman, Barbara K.; Gockerman, Jon P.; Diehl, Louis F.; de Castro, Carlos M.; Moore, Joseph O.; Vitek, Michael P.; Weinberg, J. Brice
2011-01-01
190
DOEpatents
An isolated polypeptide (JNK) characterized by having a molecular weight of 46kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.
Karin, Michael (2565 Chalcedony, San Diego, CA 92122); Hibi, Masahiko (7528 Charmant Dr., No. 418, San Diego, CA 92122); Lin, Anning (8655 Via Mallorca Dr., Apt. 93, La Jolla, CA 92093)
1997-01-01
191
DOEpatents
An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE is disclosed. The polypeptide has serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences. The method of detection of JNK is also provided. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites. 44 figs.
Karin, M.; Hibi, M.; Lin, A.
1997-02-25
192
SciTech Connect
Human papillomaviruses (HPVs) cause cervical cancer and are associated with the development of non-melanoma skin cancer. A suitable animal model for papillomavirus-associated skin carcinogenesis is the infection of domestic rabbits with the cottontail rabbit papillomavirus (CRPV). As the immortalizing activity of CRPV genes in the natural target cells remains unknown, we investigated the properties of CRPV E6 and E7 in rabbit keratinocytes (RK) and their influence on the cell cycle. Interestingly, CRPV E7 immortalized RK after a cellular crisis but showed no such activity in human keratinocytes. Co-expressed CRPV E6 prevented cellular crisis. The HPV16 or CRPV E7 protein reduced rabbit pRb levels thereby causing rabbit p19{sup ARF} induction and accumulation of p53 without affecting cellular proliferation. Both CRPV E6 proteins failed to degrade rabbit p53 in vitro or to bind E6AP; however, p53 was still inducible by mitomycin C. In summary, CRPV E7 immortalizes rabbit keratinocytes in a species-specific manner and E6 contributes to immortalization without directly affecting p53.
Ganzenmueller, Tina; Matthaei, Markus; Muench, Peter; Scheible, Michael; Iftner, Angelika; Hiller, Thomas; Leiprecht, Natalie; Probst, Sonja; Stubenrauch, Frank [Sektion Experimentelle Virologie, Universitaetsklinikum Tuebingen, 72076 Tuebingen (Germany); Iftner, Thomas [Sektion Experimentelle Virologie, Universitaetsklinikum Tuebingen, 72076 Tuebingen (Germany)], E-mail: [email protected]
2008-03-15
193
Background: Data have accumulated implicating the involvement of oncogenic human papillomaviruses (HPVs) in bronchial carcinogenesis. We recently described the presence of oncogenic HPV transcripts in non-small cell lung cancers. Objective: To investigate the role of oncogenic HPVs in lung carcinogenesis. Material and Methods: The lung cell line A549 stably infected with HPV16E6, HPV16E7 and HPVE6\\/E7 constructs was used to investigate
Marco Ciotti; Valeria Marzano; Laura Giuliani; Marzia Nuccetelli; Simona D’Aguanno; Barbara Azzimonti; Sergio Bernardini; Carlo Federico Perno; Andrea Urbani; Cartesio Favalli; Giorgio Federici
2009-01-01
194
PubMed Central
Human papillomavirus type 16 (HPV-16) associated oropharyngeal cancers are on a significant increase and better therapeutic strategies are needed. The HPV-16 oncogenes E6 and E7 are expressed in HPV-associated cancers and are able to transform human tonsillar epithelial cells (HTECs). We used cell-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) to select for RNA aptamers that entered into HPV-16 E6/E7-HTECs. After 12 rounds of cell-SELEX, a pool of aptamers was obtained that had significantly greater internalization capacity (~5-fold) into E6/E7-HTECs as compared to primary HTECs or fibroblasts. Analysis of individual aptamers from the pool indicated variable internalization into E6/E7-HTECs (1 to 8-fold as compared to a negative control). Most of the individual aptamers internalized into E6/E7 and primary HTECs with similar efficiency, while one aptamer exhibited ~3-fold better internalization into E6/E7-HTECs. Aptamers that internalize into cells may be useful for delivering therapeutic agents to HPV-16 associated malignancies. PMID:24074596
Gourronc, Francoise A.; Rockey, William M.; Thiel, William H.; Giangrande, Paloma H.; Klingelhutz, Aloysius J.
2013-01-01
195
PubMed Central
There is strong evidence implicating human papillomavirus type 16 (HPV16) in the genesis of human genital cancer. Viral DNA has been identified in invasive carcinoma of the uterine cervix and in cell lines derived from cervical carcinomas. These sequences are actively transcribed, and translation products corresponding to the early (E)-region genes have been identified. The most abundant viral protein is the E7 protein, which has been shown to possess transforming activity for both established and primary cells. In addition, it has been shown to bind to a cellular tumor suppressor, the retinoblastoma gene product (pRb-105). In view of these properties, we have undertaken the immunological analysis of this protein and have identified four T-cell epitopes and three B-cell epitopes by using a series of overlapping peptides spanning the entire HPV16 E7 sequence. Two of the B-cell epitopes were recognized by antisera from mice with three different murine (H-2) haplotypes (k, d, and s) immunized with two different E7 fusion proteins and from Fischer rats seeded with baby rat kidney cells transformed by HPV16 E7 and ras. A third B-cell epitope was recognized by antisera from CBA mice seeded with HPV16 E7-expressing L cells. Two regions of the protein contain common B- and T-cell epitopes, one of which appears to be particularly immunodominant. Images PMID:1714516
Comerford, S A; McCance, D J; Dougan, G; Tite, J P
1991-01-01
196
Tokar, R. L.; Johnson, R. E.; Thomsen, M. F.; Wilson, R. J.; Crary, F. J.; Young, D. T.; Goldstein, R.; Reisenfeld, D. B.; Sittler, E. C.; Coates, A. J.; Paty, C. S.; Jia, Y.; Omidi, N.; Russell, C.
2009-12-01
197
PubMed
The oncoprotein Tax of human T-cell leukemia virus type 1 (HTLV-1) is a potent transactivator of viral and cellular transcription. Here, we identified ELL2 as the sole transcription elongation factor to be specifically upregulated in HTLV-1-/Tax-transformed T-cells. Tax contributes to regulation of ELL2, since transient transfection of Tax increases ELL2 mRNA, Tax transactivates the ELL2 promoter, and repression of Tax results in decrease of ELL2 in transformed T-lymphocytes. However, we also measured upregulation of ELL2 in HTLV-1-transformed cells exhibiting undetectable amounts of Tax, suggesting that ELL2 can still be maintained independent of continuous Tax expression. We further show that Tax and ELL2 synergistically activate the HTLV-1 promoter, indicating that ELL2 cooperates with Tax in viral transactivation. This is supported by our findings that Tax and ELL2 accumulate in nuclear fractions and that they co-precipitate upon co-expression in transiently-transfected cells. Thus, upregulation of ELL2 could contribute to HTLV-1 gene regulation. PMID:25058508
Mann, Melanie C; Strobel, Sarah; Fleckenstein, Bernhard; Kress, Andrea K
2014-09-01
198
PubMed Central
The HBx oncoprotein of hepatitis B Virus has been accredited as one of the protagonists in driving hepatocarcinogenesis. HBx exerts its influence over the cell cycle progression by potentiating the activity of cyclin A/E-CDK2 complex, the Cyclin A partner of which is a well-known target of cellular deubiquitinase USP37. In the present study, we observed the intracellular accumulation of cyclin A and USP37 proteins under the HBx microenvironment. Flow cytometry analysis of the HBx-expressing cells showed deregulation of cell cycle apparently due to the enhanced gene expression and stabilization of USP37 protein and deubiquitination of Cyclin A by USP37. Our co-immunoprecipitation and confocal microscopic studies suggested a direct interaction between USP37 and HBx. This interaction promoted the translocation of USP37 outside the nucleus and prevented its association and ubiquitination by E3 ubiquitin ligases - APC/CDH1 and SCF/?-TrCP. Thus, HBx seems to control the cell cycle progression via the cyclin A-CDK2 complex by regulating the intracellular distribution and stability of deubiquitinase USP37. PMID:25347529
Saxena, Nehul; Kumar, Vijay
2014-01-01
199
PubMed Central
Stem cell populations are maintained through self-renewing divisions in which one daughter cell commits to a specific fate while the other retains the multipotent characteristics of its parent. The p53 tumor suppressor, in conjunction with its interacting partner protein Numb, preserves this asymmetry and functions as a vital barrier against the unchecked expansion of tumor stem cell pools; however, little is known about the biological control of the Numb-p53 interaction. We show here that Numb and p53 are the constituents of a high molecular mass complex, which is disintegrated upon activation of aPKC?, a Numb kinase. Using large-scale affinity purification and tandem mass spectrometry, we identify TBC1D15 as a Numb-associated protein and demonstrate that its amino-terminal domain disengages p53 from Numb, triggering p53 proteolysis and promoting self-renewal and pluripotency. Cellular levels of TBC1D15 are diminished upon acute nutrient deprivation through autophagy-mediated degradation, indicating that TBC1D15 serves as a conduit through which cellular metabolic status is linked to self-renewal. The profound deregulation of TBC1D15 expression exhibited in a diverse array of patient tumors underscores its proposed function as an oncoprotein. PMID:23468968
Feldman, Douglas E.; Chen, Chialin; Punj, Vasu; Machida, Keigo
2013-01-01
200
E-print Network
Elliptical galaxies are modelled as homeoidally striated Jacobi ellipsoids where the peculiar velocity distribution is anisotropic, or equivalently as their adjoints configurations i.e. classical Jacobi ellipsoids of equal mass and axes, in real or imaginary rotation. Reasons for the coincidence of bifurcation points from axisymmetric to triaxial configurations in both the sequences, contrary to earlier findings, are presented and discussed. The effect of centrifugal support at the ends of the major equatorial axis, is briefly outlined. The existence of a lower limit to the flattening of elliptical galaxies is investigated in dealing with a number of limiting situations. More specifically, (i) elliptical galaxies are considered as isolated systems, and an allowed region within Ellipsoidland, related to the occurrence of bifurcation points from ellipsoidal to pear-shaped configurations, is shown to be consistent with observations; (ii) elliptical galaxies are considered as embedded within dark matter haloes and, under reasonable assumptions, it is shown that tidal effects from hosting haloes have little influence on the above mentioned results; (iii) dark matter haloes and embedded elliptical galaxies, idealized as a single homeoidally striated Jacobi ellipsoid, are considered in connection with the cosmological transition from expansion to relaxation, by generalizing an earlier model, and the existence of a lower limit to the flattening of relaxed (oblate-like) configurations, is established. On the other hand, no lower limit is found to the elongation of relaxed (prolate-like) configurations, and the observed lack of elliptical galaxies more elongated than E7 needs a different physical interpretation, such as the fully investigated bending instabilities.
R. Caimmi
2007-04-24
201
Chromosomal translocations involving the N-terminal ?250 residues of the Ewings sarcoma (EWS) oncogene produce a group of EWS fusion proteins (EFPs) that cause several distinct human cancers. EFPs are potent transcriptional activators and interact with other proteins required for mRNA biogenesis, indicating that EFPs induce tumorigenesis by perturbing gene expression. Although EFPs were discovered more than a decade ago, molecular
King Pan Ng; Gary Potikyan; Rupert O. V. Savene; Christopher T. Denny; Vladimir N. Uversky; Kevin A. W. Lee
2007-01-01
202
PubMed Central
Background Active infection by bovine papillomavirus type 2 (BPV-2) was documented for fifteen urinary bladder tumors in cattle. Two were diagnosed as papillary urothelial neoplasm of low malignant potential (PUNLMP), nine as papillary and four as invasive urothelial cancers. Methods and Findings In all cancer samples, PCR analysis revealed a BPV-2-specific 503 bp DNA fragment. E5 protein, the major oncoprotein of the virus, was shown both by immunoprecipitation and immunohistochemical analysis. E5 was found to bind to the activated (phosphorylated) form of the platelet derived growth factor ? receptor. PDGF?R immunoprecipitation from bladder tumor samples and from normal bladder tissue used as control revealed a protein band which was present in the pull-down from bladder cancer samples only. The protein was identified with mass spectrometry as “V1-ATPase subunit D”, a component of the central stalk of the V1-ATPase vacuolar pump. The subunit D was confirmed in this complex by coimmunoprecipitation investigations and it was found to colocalize with the receptor. The subunit D was also shown to be overexpressed by Western blot, RT-PCR and immunofluorescence analyses. Immunoprecipitation and immunofluorescence also revealed that E5 oncoprotein was bound to the subunit D. Conclusion For the first time, a tri-component complex composed of E5/PDGF?R/subunit D has been documented in vivo. Previous in vitro studies have shown that the BPV-2 E5 oncoprotein binds to the proteolipid c ring of the V0-ATPase sector. We suggest that the E5/PDGF?R/subunit D complex may perturb proteostasis, organelle and cytosol homeostasis, which can result in altered protein degradation and in autophagic responses. PMID:24586417
Roperto, Sante; Russo, Valeria; Borzacchiello, Giuseppe; Urraro, Chiara; Lucà, Roberta; Esposito, Iolanda; Riccardi, Marita Georgia; Raso, Cinzia; Gaspari, Marco; Ceccarelli, Dora Maria; Galasso, Rocco; Roperto, Franco
2014-01-01
203
PubMed
High-risk human papillomaviruses are causative agents of cervical cancer. Viral protein E7 is required to establish and maintain the pro-oncogenic phenotype in infected cells, but the molecular mechanisms by which E7 promotes carcinogenesis are only partially understood. Our transcriptome analyses in primary human fibroblasts transduced with the viral protein revealed that E7 activates a group of mitotic genes via the activator B-Myb-MuvB complex. We show that E7 interacts with the B-Myb, FoxM1 and LIN9 components of this activator complex, leading to cooperative transcriptional activation of mitotic genes in primary cells and E7 recruitment to the corresponding promoters. E7 interaction with LIN9 and FoxM1 depended on the LXCXE motif, which is also required for pocket protein interaction and degradation. Using E7 mutants for the degradation of pocket proteins but intact for the LXCXE motif, we demonstrate that E7 functional interaction with the B-Myb-MuvB complex and pocket protein degradation are two discrete functions of the viral protein that cooperate to promote acute transcriptional activation of mitotic genes. Transcriptional level of E7 in patient's cervical lesions at different stages of progression was shown to correlate with those of B-Myb and FoxM1 as well as other mitotic gene transcripts, thereby linking E7 with cellular proliferation and progression in cervical cancer in vivo. E7 thus can directly activate the transcriptional levels of cell cycle genes independently of pocket protein stability. PMID:24141769
Pang, C L; Toh, S Y; He, P; Teissier, S; Ben Khalifa, Y; Xue, Y; Thierry, F
2014-07-31
204
PubMed Central
The ets gene family encodes a group of proteins which function as transcription factors under physiological conditions and, if aberrantly expressed, can cause cellular transformation. We have recently identified two regulatory elements in the murine immunoglobulin heavy-chain (IgH) enhancer, pi and microB, which exhibit striking similarity to binding sites for ets-related proteins. To identify ets-related transcriptional regulators expressed in pre-B lymphocytes that may interact with either the pi or the microB site, we have used a PCR approach with degenerate oligonucleotides encoding conserved sequences in all members of the ets family. We have cloned the gene for a new ets-related transcription factor, ERP (ets-related protein), from the murine pre-B cell line BASC 6C2 and from mouse lung tissue. The ERP protein contains a region of high homology with the ETS DNA-binding domain common to all members of the ets transcription factor/oncoprotein family. Three additional smaller regions show homology to the ELK-1 and SAP-1 genes, a subgroup of the ets gene family that interacts with the serum response factor. Full-length ERP expresses only negligible DNA-binding activity by itself. Removal of the carboxy terminus enables ERP to interact with a variety of ets-binding sites including the E74 site, the IgH enhancer pi site, and the lck promoter ets site, suggesting a carboxy-terminal negative regulatory domain. At least three ERP-related transcripts are expressed in a variety of tissues. However, within the B-cell lineage, ERP is highly expressed primarily at early stages of B-lymphocyte development, and expression declines drastically upon B-cell maturation, correlating with the enhancer activity of the IgH pi site. These data suggest that ERP might play a role in B-cell development and in IgH gene regulation. Images PMID:7909357
Lopez, M; Oettgen, P; Akbarali, Y; Dendorfer, U; Libermann, T A
1994-01-01
205
PubMed Central
The p210 bcr-abl protein tyrosine kinase (PTK) appears to be directly responsible for the initial manifestations of chronic myelogenous leukemia (CML). In contrast to the extensive characterization of the PTK and its effects on cell function, relatively little is known about the nature of the protein tyrosine phosphatases (PTPs) that may modulate p210 bcr-abl-induced signalling. In this study, we have demonstrated that expression of PTP1B is enhanced specifically in various cells expressing p210 bcr-abl, including a cell line derived from a patient with CML. This effect on expression of PTP1B required the kinase activity of p210 bcr-abl and occurred rapidly, concomitant with maximal activation of a temperature-sensitive mutant of the PTK. The effect is apparently specific for PTP1B since, among several PTPs tested, we detected no change in the levels of TCPTP, the closest relative of PTP1B. We have developed a strategy for identification of physiological substrates of individual PTPs which utilizes substrate-trapping mutant forms of the enzymes that retain the ability to bind to substrate but fail to catalyze efficient dephosphorylation. We have observed association between a substrate-trapping mutant of PTP1B (PTP1B-D181A) and p210 bcr-abl, but not v-Abl, in a cellular context. Consistent with the trapping data, we observed dephosphorylation of p210 bcr-abl, but not v-Abl, by PTP1B in vivo. We have demonstrated that PTP1B inhibited binding of the adapter protein Grb2 to p210 bcr-abl and suppressed p210 bcr-abl-induced transcriptional activation that is dependent on Ras. These results illustrate selectivity in the effects of PTPs in a cellular context and suggest that PTP1B may function as a specific, negative regulator of p210 bcr-abl signalling in vivo. PMID:9566916
LaMontagne, Kenneth R.; Flint, Andrew J.; Franza, B. Robert; Pendergast, Ann Marie; Tonks, Nicholas K.
1998-01-01
206
PubMed
Human papillomavirus 8 (HPV8) is one of the oncogenic HPV types specifically associated with skin cancers of epidermodysplasia verruciformis patients. The early gene products of this virus exert functions in transformation (E2, E6, E7), replication (E1, E2) and in the control of viral transcription (E2, E7). Many viral and cellular transactivators of transcription have been shown to interact selectively and directly with a number of TATA-box-binding protein (TBP)-associated factors (TAFIIs), which then play a role as coactivators. Using glutathione-S-transferase (GST) pull-down experiments, we tested in vitro interactions between GST-HPV8-E1, -E2, -E6 and -E7 and 7 in-vitro-translated TAFIIs in the human (h) system (hTAFII18, hTAFII20, hTAFII28, hTAFII30, hTAFII55, hTAFII100, hTAFIIDeltaN135) or TBP. We could show that GST-HPV8-E2 interacts directly at least with hTAFII55 and TBP. Deletion analysis indicated that a domain overlapping with the C-terminal moiety of HPV8-E2 is required for binding to TBP, whereas determinants for interactions with hTAFII55 are in the central and C-terminal part of the E2 protein. In similar binding studies, GST-HPV8-E6 interacted with hTAFII28, hTAFIIDeltaN135 and TBP, and more weakly with hTAFII20, whereas GST- HPV8-E7 bound to hTAFII20, hTAFII28, hTAFII55, hTAFIIDeltaN135 and TBP. Deletion analysis revealed that the C-terminal part of HPV8-E7 is required for the interaction with these hTAFIIs. In contrast, no interactions were observed between GST-HPV8-E1 and in-vitro-translated hTAFIIs. PMID:9820841
Enzenauer, C; Mengus, G; Lavigne, A; Davidson, I; Pfister, H; May, M
1998-01-01
207
PubMed
sno is a member of the ski oncogene family and shares ski 's ability to transform avian fibroblasts and induce muscle differentiation. Ski and SnoN are transcription factors that form both homodimers and heterodimers. They recognize a specific DNA binding site (GTCTAGAC) through which they repress transcription. Efficient homodimerization of Ski, mediated by a bipartite C-terminal domain consisting of five tandem repeats (TR) and a leucine zipper (LZ), correlates with efficient DNA binding and cellular transformation. The present study assesses the role of SnoN homodimerization and SnoN:Ski heterodimerization in the activities of these proteins. Unlike Ski, efficient homodimerization by SnoN is shown to require an upstream region of the protein in addition to the TR/LZ domain. Deletion of the TR/LZ from SnoN decreases its activity in transcriptional repression and cellular transformation. When co-expressed in vitro, c-Ski and SnoN preferentially form heterodimers. In vivo, they form heterodimers that bind the GTCTAGAC element. Tethered Ski:Sno hetero-dimers that lack TR/LZ domains are more active than either their monomeric counterparts, tethered Ski:Ski homodimers or full-length SnoN and c-Ski. This work demonstrates, for the first time, the differences between dimer formation by Ski and SnoN and underscores the importance of dimerization in their activity. PMID:9927733
Cohen, S B; Zheng, G; Heyman, H C; Stavnezer, E
1999-02-15
208
PubMed Central
PIM kinases are a family of serine/threonine kinases involved in cell survival and proliferation. There is significant structural similarity between the three PIM kinases (PIM1, PIM2 and PIM3) and few amino acid differences. Although, several studies have specifically monitored the role of PIM1 in tumorigenesis, much less is known about PIM2 and PIM3. Therefore, in this study we have used in vitro cell culture models and in vivo bone marrow infection/transplantation to assess the comparative signaling and oncogenic potential of each of the three PIM kinases. All three PIM kinases were able to protect FL5.12 cells from IL-3 withdrawal induced death. Interestingly, the downstream signaling cascades were indistinguishable between the three kinases. Transplantation of murine bone marrow co-expressing MYC and PIM1, PIM2 or PIM3 caused rapid and uniformly lethal myeloid leukemia. De-induction of MYC 18 days following transplantation significantly increased the survival of mice, even with continual expression of PIM kinases. Alternatively, mice treated at the pre-leukemic stage with a PIM kinase inhibitor increased the lifespan of the mice, even with continual expression of the MYC transgene. These data demonstrate the role of PIM kinases in driving myeloid leukemia, and as candidate molecules for therapy against human malignancies. PMID:25238262
Shah, Parag P.; Mims, Alice S.; Lockwood, William W.; Kraft, Andrew S.; Beverly, Levi J.
2014-01-01
209
PubMed
Chromosomal translocations involving the N-terminal approximately 250 residues of the Ewings sarcoma (EWS) oncogene produce a group of EWS fusion proteins (EFPs) that cause several distinct human cancers. EFPs are potent transcriptional activators and interact with other proteins required for mRNA biogenesis, indicating that EFPs induce tumorigenesis by perturbing gene expression. Although EFPs were discovered more than a decade ago, molecular analysis has been greatly hindered by the repetitive EWS activation domain (EAD) structure, containing multiple degenerate hexapeptide repeats (consensus SYGQQS) with a conserved tyrosine residue. By exploiting total gene synthesis, we have been able to systematically mutagenize the EAD and determine the effect on transcriptional activation by EWS/ATF1 and cellular transformation by EWS/Fli1. In both assays, we find the following requirements for EAD function. First, multiple tyrosine residues are essential. Second, phenylalanine can effectively substitute for tyrosine, showing that an aromatic ring can confer EAD function in the absence of tyrosine phosphorylation. Third, there is little requirement for specific peptide sequences and, thus, overall sequence composition (and not the degenerate hexapeptide repeat) confers EAD activity. Consistent with the above findings, we also report that the EAD is intrinsically disordered. However, a sensitive computational predictor of natural protein disorder (PONDR VL3) identifies potential molecular recognition features that are tyrosine-dependent and that correlate well with EAD function. In summary we have uncovered several molecular features of the EAD that will impact future studies of the broader EFP family and molecular recognition by complex intrinsically disordered proteins. PMID:17202261
Ng, King Pan; Potikyan, Gary; Savene, Rupert O V; Denny, Christopher T; Uversky, Vladimir N; Lee, Kevin A W
2007-01-01
210
PubMed
Infection with cagA-positive Helicobacter pylori is associated with gastric adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT) lymphoma of B cell origin. The cagA-encoded CagA protein is delivered into gastric epithelial cells via the bacterial type IV secretion system and, upon tyrosine phosphorylation by Src family kinases, specifically binds to and aberrantly activates SHP-2 tyrosine phosphatase, a bona fide oncoprotein in human malignancies. CagA also elicits junctional and polarity defects in epithelial cells by interacting with and inhibiting partitioning-defective 1 (PAR1)/microtubule affinity-regulating kinase (MARK) independently of CagA tyrosine phosphorylation. Despite these CagA activities that contribute to neoplastic transformation, a causal link between CagA and in vivo oncogenesis remains unknown. Here, we generated transgenic mice expressing wild-type or phosphorylation-resistant CagA throughout the body or predominantly in the stomach. Wild-type CagA transgenic mice showed gastric epithelial hyperplasia and some of the mice developed gastric polyps and adenocarcinomas of the stomach and small intestine. Systemic expression of wild-type CagA further induced leukocytosis with IL-3/GM-CSF hypersensitivity and some mice developed myeloid leukemias and B cell lymphomas, the hematological malignancies also caused by gain-of-function SHP-2 mutations. Such pathological abnormalities were not observed in transgenic mice expressing phosphorylation-resistant CagA. These results provide first direct evidence for the role of CagA as a bacterium-derived oncoprotein (bacterial oncoprotein) that acts in mammals and further indicate the importance of CagA tyrosine phosphorylation, which enables CagA to deregulate SHP-2, in the development of H. pylori-associated neoplasms. PMID:18192401
Ohnishi, Naomi; Yuasa, Hitomi; Tanaka, Shinya; Sawa, Hirofumi; Miura, Motohiro; Matsui, Atsushi; Higashi, Hideaki; Musashi, Manabu; Iwabuchi, Kazuya; Suzuki, Misao; Yamada, Gen; Azuma, Takeshi; Hatakeyama, Masanori
2008-01-22
211
PubMed
To construct and express a composite gene vaccine for human papillomavirus 58(HPV58)-associated cervical cancer, we inserted HPV58mE6E7 fusion gene into pCI-Fc-GPI eukaryotic expression vector, constructing a recombinant plasmid named pCI-sig-HPV58mE6E7-Fc-GPI. Then we further inserted fragment of sig-HPV58mE6E7Fc-GPI into the novel vaccine vector PVAX1-IRES-GM/B7, constructing PVAX1-HPV58mE6E7FcGB composite gene vaccine. PVAX1-HPV58mE6E7FcGB vaccine was successfully constructed and identified by restriction endonuclease and sequencing analysis. Eukaryotic expression of fusion antigen sig-HPV58mE6E7-Fc-GPI and molecular ad-juvant GM-CSF and B7. 1 were proved to be realized at the same time by flow cytometry and immunofluorescence. So PVAX1-HPV58mE6E7FcGB can be taken as a candidate of therapeutic vaccine for HPV58-associated tumors and their precancerous transformations. PMID:24459978
Wang, He; Yu, Jiyun; Li, Li
2013-10-01
212
PubMed
The progress of DNA vaccines is dependent on the development of suitable chromatographic procedures to successfully purify genetic vectors, such as plasmid DNA. Human Papillomavirus is associated with the development of tumours due to the oncogenic power of E6 and E7 proteins, produced by this virus. The supercoiled HPV-16 E6/E7 plasmid-based vaccine was recently purified with the arginine monolith, with 100% of purity, but only 39% of recovery was achieved. Therefore, the present study describes the application of experimental design tools, a newly explored methodology in preparative chromatography, in order to improve the supercoiled plasmid DNA recovery with the arginine monolith, maintaining the high purity degree. In addition, the importance and influence of pH in the pDNA retention to the arginine ligand was also demonstrated. The Composite Central Face design was validated and the recovery of the target molecule was successfully improved from 39% to 83.5%, with an outstanding increase of more than double, while maintaining 100% of purity. PMID:25544011
Almeida, A M; Queiroz, J A; Sousa, F; Sousa, A
2015-01-26
213
PubMed
Antibody generation by phage display and related in vitro display technologies routinely yields large panels of clones detected in primary end-point screenings such as enzyme-linked immunosorbent assay (ELISA). However, for the development of clinical lead candidates, rapid determination of secondary characteristics such as kinetics and thermodynamics is of nearly equal importance. Surface plasmon resonance-based biosensors are ideal tools for carrying out such high-throughput secondary screenings, allowing preliminary but confident ranking and identification of lead clones. A key feature of these assays is the stable and reversible capture of antibody fragments from crude samples leading to high-resolution kinetic analysis of library outputs. Here we exploit the high-affinity interaction between the naturally occurring nuclease domain of E. coli colicin E7 (DNaseE7) and its cognate partner, the immunity protein 7 (Im7), to develop a ligand capture system suitable for accurate kinetic ranking of library clones. We demonstrate generic applicability for a range of antibody formats: scFv antibodies, diabodies, antigen binding fragments (Fabs), and shark V(NAR) single domain antibodies. The system is adaptable and reproducible, with comparable results achieved for both the Biacore T100 and ProteOn XPR36 array biosensors. PMID:19073134
Hosse, Ralf J; Tay, Leigh; Hattarki, Meghan K; Pontes-Braz, Luisa; Pearce, Lesley A; Nuttall, Stewart D; Dolezal, Olan
2009-02-15
214
PubMed
Genetic variations of High-Risk HPV E6/E7 may be associated with the development of cervical cancer in specific geographic regions. Few data have been reported about the HPV prevalence and E6/E7 variants among cervical cancer patients in Southwest China. This study was designed to investigate the prevalence of HPV and E6/E7 variants of most prevalent HPV among cervical cancer patients in Southwest China. After genotyping, E6/E7 genes of most prevalent HR HPV samples were sequenced and analyzed. Phylogenetic trees were then constructed, followed by an analysis of the diversity of secondary structure and selection pressures. HPV 16 (73.8%) and HPV 18 (16.4%) are the most prevalent infection types among cervical cancer patients, followed by HPV 58, HPV 56 and HPV 59, which is different from the high HPV 58 infection rate of outpatients in this region. Eighteen single nucleotide changes were observed in HPV 16 E6 with 13/18 non-synonymous mutations (5 in beta sheet and 2 in alpha helix). Ten single nucleotide changes were identified among HPV 16 E7 with 3/10 non-synonymous mutations. Three single nucleotide changes were observed in HPV 18 E6 with one non-synonymous mutation, and only one synonymous mutation was identified in HPV 18 E7. HPV 16 E6-D25E, E7-N29S and E7-T846C (S95S) exhibited a prevalent linkage mutation. The phylogenetic tree demonstrates that European and Asian lineages were the main patterns. This study may help understand the intrinsic geographical relatedness and oncogenic potential of HR HPV and contributes further to research of diagnostic, therapeutic and therapeutic vaccine strategy. PMID:25111286
Yang, Lijuan; Yang, Hongying; Wu, Kun; Shi, Xinan; Ma, Shaohui; Sun, Qiangming
2014-11-01
215
PubMed
BackgroundCervical lesions caused by integrated human papillomavirus (HPV) infection are highly dangerous because they can quickly develop into invasive cancers. However, clinicians are currently hampered by the lack of a quick, convenient and precise technique to detect integrated/mixed infections of various genotypes of HPVs in the cervix. This study aimed to develop a practical tool to determine the physical status of different HPVs and evaluate its clinical significance.MethodsThe target population comprised 1162 women with an HPV infection history of¿>¿six months and an abnormal cervical cytological finding. The multiple E1-L1/E6E7 ratio analysis, a novel technique, was developed based on determining the ratios of E1/E6E7, E2/E6E7, E4E5/E6E7, L2/E6E7 and L1/E6E7 within the viral genome. Any imbalanced ratios indicate integration. Its diagnostic and predictive performances were compared with those of E2/E6E7 ratio analysis. The detection accuracy of both techniques was evaluated using the gold-standard technique ¿detection of integrated papillomavirus sequences¿ (DIPS). To realize a multigenotypic detection goal, a primer and probe library was established.ResultsThe integration rate of a particular genotype of HPV was correlated with its tumorigenic potential and women with higher lesion grades often carried lower viral loads. The E1-L1/E6E7 ratio analysis achieved 92.7% sensitivity and 99.0% specificity in detecting HPV integration, while the E2/E6E7 ratio analysis showed a much lower sensitivity (75.6%) and a similar specificity (99.3%). Interference due to episomal copies was observed in both techniques, leading to false-negative results. However, some positive results of E1-L1/E6E7 ratio analysis were missed by DIPS due to its stochastic detection nature. The E1-L1/E6E7 ratio analysis is more efficient than E2/E6E7 ratio analysis and DIPS in predicting precancerous/cancerous lesions, in which both positive predictive values (36.7%-82.3%) and negative predictive values (75.9%-100%) were highest (based on the results of three rounds of biopsies).ConclusionsThe multiple E1-L1/E6E7 ratio analysis is more sensitive and predictive than E2/E6E7 ratio analysis as a triage test for detecting HPV integration. It can effectively narrow the range of candidates for colposcopic examination and cervical biopsy, thereby lowering the expense of cervical cancer prevention. PMID:25269554
Zhang, Rong; He, Yi-Feng; Chen, Mo; Chen, Chun-Mei; Zhu, Qiu-Jing; Lu, Huan; Wei, Zhen-Hong; Li, Fang; Zhang, Xiao-Xin; Xu, Cong-Jian; Yu, Long
2014-10-01
216
PubMed Central
Human papillomavirus (HPV) DNA testing has a higher clinical sensitivity than cytology for the detection of high-grade cervical intraepithelial neoplasia or worse (CIN 2+). However, an improvement in specificity would be desirable. As malignant transformation is induced by HPV E6/E7 oncogenes, detection of E6/E7 oncogene activity may improve specificity and be more predictive of cervical cancer risk. The PreTect HPV-Proofer assay (Proofer; Norchip) detects E6/E7 mRNA transcripts from HPV types 16, 18, 31, 33, and 45 with simultaneous genotype-specific identification. The clinical performance of this assay was assessed in a cross-sectional study of women referred for colposcopy in comparison with the Hybrid Capture 2 (HC2; Qiagen) test, which detects DNA of 13 high-risk oncogenic HPV types collectively. Cervical specimens were collected in PreservCyt, and cytology was performed using the ThinPrep method (Hologic). The samples were processed for HPV detection with Proofer and HC2 and genotyping with the Linear Array method (Roche Molecular Systems). Histology-confirmed CIN 2+ served as the disease endpoint to assess the clinical performance of the tests. A total of 1,551 women were studied, and of these, 402 (25.9%) were diagnosed with CIN 2+ on histology. The Proofer assay showed a sensitivity of 78.1% (95% confidence interval [CI], 74.1 to 82.1) versus 95.8% (95% CI, 93.8 to 97.8) for HC2 (P < 0.05) and a specificity of 75.5% (95% CI, 73.0 to 78.0) versus 39.6% (95% CI, 36.8 to 42.4), respectively (P < 0.05). The lower sensitivity and higher specificity of Proofer for detection of CIN 2+ can be attributed to the fact that this test detects the expression of E6/E7 genes beyond a threshold from a limited number of oncogenic HPV types. In conclusion, Proofer is more specific than HC2 in identifying women with CIN 2+ but has a lower sensitivity. PMID:20573862
Ratnam, Samuel; Coutlee, Francois; Fontaine, Dan; Bentley, James; Escott, Nicholas; Ghatage, Prafull; Gadag, Veeresh; Holloway, Glen; Bartellas, Elias; Kum, Nick; Giede, Christopher; Lear, Adrian
2010-01-01
217
DOEpatents
An isolated polypeptide (JNK) characterized by having a molecular weight of 46 kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.
Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA)
2008-12-23
218
PubMed Central
Human papillomavirus type 18 (HPV18) is a common cause of cervical cancer. To create a mouse model for this common neoplastic disease we used a human keratin 14 promoter to drive the HPV18 E7 oncogene to create transgenic mice. No mice up to a year of age developed cervical cancer. However, all transgenic mice and none of the controls developed progressive bilateral cortical cataracts. By 6 months of age the cortex liquefied leaving the lens nucleus. Proliferation of lens epithelium formed multifocal nodules and free floating lens epithelial cells within the liquefied cortex. These cells were hyperplastic not neoplastic. Other HPV transgenic stocks develop cataracts suggesting this virus may have a broad cellular tropism. PMID:18723014
Ghim, Shinje; Jenson, A. Bennett; Bubier, Jason A.; Silva, Kathleen A.; Smith, Richard S.; Sundberg, John P.
2008-01-01
219
PubMed Central
Cervical cancer is still one of the leading causes of cancer deaths in women worldwide, especially in the developing countries. It is a major metabolic character of cancer cells to consume large quantities of glucose and derive more energy by glycolysis even in the presence of adequate oxygen, which is called Warburg effect that can be exaggerated by hypoxia. The high risk subtype HPV16 early oncoprotein E6 contributes host cell immortalization and transformation through interacting with a number of cellular factors. Hypoxia-inducible factor 1? (HIF-1?), a ubiquitously expressed transcriptional regulator involved in induction of numerous genes associated with angiogenesis and tumor growth, is highly increased by HPV E6. HIF-1? is a best-known target of the von Hippel-Lindau tumor suppressor (VHL) as an E3 ligase for degradation. In the present work, we found that HPV16 E6 promotes hypoxia induced Warburg effect through hindering the association of HIF-1? and VHL. This disassociation attenuates VHL-mediated HIF-1? ubiquitination and causes HIF-1? accumulation. These results suggest that oncoprotein E6 plays a major role in the regulation of Warburg effect and can be a valuable therapeutic target for HPV-related cancer. PMID:24810689
Guo, Yi; Meng, Xiangkai; Ma, Jiaming; Zheng, Yahong; Wang, Qian; Wang, Yanan; Shang, Hong
2014-01-01
220
PubMed
Vitamin C is considered as an important anticancer therapeutic agent although this view is debatable. In this study, we introduce a physiological mechanism demonstrating how vitamin C exerts anticancer activity that induces cell cycle arrest and apoptosis. Our previous and current data reveal that p53 tumor suppressor is the prerequisite factor for stronger anticancer effects of vitamin C. In addition, vitamin C-mediated cancer cell cytotoxicity appears to be achieved at least partly through the downregulation of the p34SEI-1 oncoprotein. Our previous study showed that p34SEI-1 increases the survival of various types of cancer cells by inhibiting their apoptosis. Present data suggest that vitamin C treatment decreases the p34SEI-1 expression at the protein level and therefore alleviates its anti-apoptotic activity. Of note, SIAH1, E3 ubiquitin ligase, appears to be responsible for the p34SEI-1 polyubiquitination and its subsequent degradation, which is dependent on p53. In summary, vitamin C increases cancer cell death by inducing SIAH1-mediated polyubiquitination/degradation of the p34SEI-1 oncoprotein in a p53-dependent manner. PMID:25586269
Lee, Soonduck; Kim, Jinsun; Jung, Samil; Li, Chengping; Yang, Young; Kim, Keun Il; Lim, Jong-Seok; Kim, Yonghwan; Cheon, Choong-Il; Lee, Myeong-Sok
2015-03-01
221
PubMed
The nuclease domain of colicin E7 metallonuclease (NColE7) contains its active centre at the C-terminus. The mutant ?N4-NColE7-C* - where the four N-terminal residues including the positively charged K446, R447 and K449 are replaced with eight residues from the GST tag - is catalytically inactive. The crystal structure of this mutant demonstrates that its overall fold is very similar to that of the native NColE7 structure. This implicates the stabilizing effect of the remaining N-terminal sequence on the structure of the C-terminal catalytic site and the essential role of the deleted residues in the mechanism of the catalyzed reaction. Complementary QM/MM calculations on the protein-DNA complexes support the less favourable cleavage by the mutant protein than by NColE7. Furthermore, a water molecule as a possible ligand for the Zn(2+)-ion is proposed to play a role in the catalytic process. These results suggest that the mechanism of the Zn(2+)-containing HNH nucleases needs to be further studied and discussed. PMID:25179124
Czene, Anikó; Tóth, Eszter; Németh, Eszter; Otten, Harm; Poulsen, Jens-Christian N; Christensen, Hans E M; Rulíšek, Lubomír; Nagata, Kyosuke; Larsen, Sine; Gyurcsik, Béla
2014-11-01
222
Genes of the polycomb group function by silencing homeotic selector genes that regulate embryogenesis. In mice, downregulation of one of the polycomb genes, bmi-1, leads to neurological alterations and severe proliferative defects in lymphoid cells, whilst bmi-1 overexpression, together with upregulation of myc-1, induces lymphoma. An oncogenic function has been further supported in primary fibroblast studies where bmi-1 overexpression induces
S Vonlanthen; J Heighway; H J Altermatt; M Gugger; A Kappeler; M M Borner; M van Lohuizen; D C Betticher
2001-01-01
223
SciTech Connect
In most cervical carcinoma cells the E6 and E7 genes of specific human papillomaviruses are transcribed from viral sequences integrated into host cell chromosomes. Glucocorticoids activate the promoter elements of various human papillomaviruses in transient-expression assays. The authors have analyzed the effect of dexamethasone on the transcription rate of human papillomaviruses 18 E6 and E7 genes integrated at different chromosomal sites in four cervical cancer cell lines. Dexamethasone led to an increase in the transcription rate of the integrated E6-E7 sequences in C4-1 and C4-2 cells but led to a decrease in SW 756 cells and did not affect the transcription rate in HeLa cells. It thus appears that dominant regulatory mechanisms presumably depending on the chromosomal integration site are able to override the response of the viral promoter to steroid hormones. The growth rate of all dexamethasone-treated cell lines correlated consistently with the expression of the papillomavirus E6 and E7 genes, supporting their role in the maintenance of the proliferative phenotype of cervical carcinoma cells. Since human papillomaviruses are integrated into the host cell genome at variable, presumably randomly selected chromosomal loci, regulatory mechanisms that influence viral gene expression, and hence cell growth, may differ among cancers of independent clonal origin.
Von Knebel Doeberitz, M.; Bauknecht, T.; Bartsch, D.; Zur Hausen, H. (Inst. fur Virusforshung/ATV, Heidelberg (West Germany))
1991-02-15
224
Extending results of 1112.3984, we show that all rank 1 {N}=2 SCFT's in the sequence H 1, H 2, D 4 E 6, E 7, E 8 have canonical finite BPS chambers containing precisely 2 h(F) = 12(? - 1) hypermultiplets. The BPS spectrum of the canonical BPS chambers saturates the conformal central charge c, and satisfies some intriguing numerology.
Cecotti, Sergio; Del Zotto, Michele
2013-06-01
225
PubMed Central
Imatinib mesylate is a targeted therapy that acts by inhibiting tyrosine kinase of the bcr-abl fusion oncoprotein, which is specific to chronic myeloid leukemia (CML), and the c-transmembrane receptor, which is specific to gastrointestinal stromal tumors. Interstitial pneumonitis is a rare adverse event of imatinib therapy. It is clinically difficult to distinguish from infectious pneumonia, which can frequently occur due to the underlying disease. The standard treatment for imatinib-induced pneumonitis is to discontinue the medication and optionally administer corticosteroids. However, there are a few cases of successful retrial with imatinib. We describe a case of successful rechallenge of imatinib in a patient with imatinib-induced interstitial pneumonitis and CML without a recurrence of the underlying disease after 3 months of follow-up. PMID:24416057
Go, Seong Woo; Kim, Boo Kyeong; Lee, Sung Hak; Kim, Tae-Jung; Huh, Joo Yeon; Lee, Jong Min; Hah, Jick Hwan; Kim, Dong Whi; Cho, Min Jung; Kim, Tae Wan
2013-01-01
226
PubMed
The viral E2 gene product plays a crucial role in the human papillomavirus (HPV) vegetative cycle by regulating both transcription and replication of the viral genome. E2 is a transcriptional repressor of the E6 and E7 viral oncogenes for HPV types 16 and 18, which are involved in cervical cancers. Using new polyclonal antibodies against the HPV16 E2 protein, we showed that E2 is expressed at various precursor stages of cervical carcinoma by immunohistochemistry on paraffin-embedded clinical samples. E2 was found to be highly expressed in the nuclei and cytoplasm of cells forming the intermediate and upper layers of cervical intraepithelial neoplasia (CIN). We could show that the expressions of E2 and p16(INK4a) (surrogate marker for oncogenic E7 expression) were exclusive in most of the cases, thus implying that E2 is not expressed together with high levels of E7. Moreover, we found that E2 is expressed in a subset of columnar cells adjacent to the CIN. We could show that expression of E2 is topologically distinct from the proliferation markers p63 and Ki67, whereas it coincides with the expression of cytokeratin K13, a marker of squamous cell differentiation. Expression of E2 also topologically coincides with episomal amplification of viral genomes in the upper layers of CIN1. These in vivo data thus validate previous assumptions of the crucial role of E2 in the early steps of HPV infection and of its negative link with expression of the viral E6 and E7 oncogenes. PMID:20530671
Xue, Yuezhen; Bellanger, Sophie; Zhang, Wenying; Lim, Diana; Low, Jeffrey; Lunny, Declan; Thierry, Françoise
2010-07-01
227
Human papillomavirus type 16 DNA and RNA were characterized in the cervical cancer-derived CaSki cell line, which contains only integrated DNA, and in a cervical cancer, which contains predominantly plasmid DNA. In both, a major RNA can code for the early open reading frame E7 and a minor one can code for E6. The cervical cancer, but not the CaSki
David Smotkin; Felix O. Wettstein
1986-01-01
228
The behavioral and electrophysiological activity of a mimic [(Z,E)7,9,11-dodecatrienyl formate] of the major sex pheromone component [(Z,E) 9,11,13-tetradecatrienal] of carob moth was assessed. Wind-tunnel bioassays demonstrated that the formate was as effective as natural gland extracts, and significantly more effective than the trienal alone or than the trienal blended with two minor pheromone components, in evoking source contact. Dispensers containing
J. L. Todd; J. G. Millar; R. S. Vetter; T. C. Baker
1992-01-01
229
E-print Network
Extending results of arXiv:1112.3984, we show that all rank 1 N=2 SCFT's in the sequence H_1, H_2, D_4 E_6, E_7, E_8 have canonical finite BPS chambers containing precisely 2 h(F)=12(Delta-1) hypermultiplets. The BPS spectrum of the canonical BPS chambers saturates the conformal central charge c, and satisfies some intriguing numerology.
Cecotti, Sergio
2013-01-01
230
E-print Network
Extending results of arXiv:1112.3984, we show that all rank 1 N=2 SCFT's in the sequence H_1, H_2, D_4 E_6, E_7, E_8 have canonical finite BPS chambers containing precisely 2 h(F)=12(Delta-1) hypermultiplets. The BPS spectrum of the canonical BPS chambers saturates the conformal central charge c, and satisfies some intriguing numerology.
Sergio Cecotti; Michele Del Zotto
2013-04-02
231
PubMed Central
Human anaplastic thyroid cancer (ATC) is a lethal disease with an advanced clinical presentation and median survival of 3 months. The BRAFV600E oncoprotein is a potent transforming factor that causes human thyroid cancer cell progression in vitro and in vivo; therefore, we sought to target this oncoprotein in a late intervention model of ATC in vivo. We used the human ATC cell line 8505c, which harbors the BRAFV600E and TP53R248G mutations. Immunocompromised mice were randomized to receive the selective anti-BRAFV600E inhibitor, PLX4720, or vehicle by oral gavage 28 d after tumor implantation, 1 wk before all animals typically die due to widespread metastatic lung disease and neck compressive symptoms in this model. Mice were euthanized weekly to evaluate tumor volume and metastases. Control mice showed progressive tumor growth and lung metastases by 35 d after tumor implantation. At that time, all control mice had large tumors, were cachectic, and were euthanized due to their tumor-related weight loss. PLX4720-treated mice, however, showed a significant decrease in tumor volume and lung metastases in addition to a reversal of tumor-related weight loss. Mouse survival was extended to 49 d in PLX4720-treated animals. PLX4720 treatment inhibited cell cycle progression from 28 d to 49 d in vivo. PLX4720 induces striking tumor regression and reversal of cachexia in an in vivo model of advanced thyroid cancer that harbors the BRAFV600E mutation. PMID:22202162
Nehs, Matthew A.; Nucera, Carmelo; Nagarkatti, Sushruta S.; Sadow, Peter M.; Morales-Garcia, Dieter; Hodin, Richard A.
2012-01-01
232
Exposure of normal mouse fibroblasts (MEF3T3) to ionizing radiation (IR) resulted in a dose-dependent increase of mTOR mRNA and protein levels and the shuttling of the mTOR protein from its normal, predomi- nantly mitochondrial location to the cell nucleus. The same IR doses that activated mTOR induced the phosphorylation of p53 on Ser18 (mouse equivalent to human Ser15) and the
Oscar M. Tirado; Silvia Mateo-Lozano; Sean Sanders; Luis E. Dettin; Vicente Notario
2003-01-01
233
PubMed
A number of epigenetic alterations occur in both the virus and host cellular genomes during human papillomavirus (HPV)-associated carcinogenesis, and investigations of such alterations, including changes in chromatin proteins and histone modifications, have the potential to lead to therapeutic epigenetic reversion. We report here that transformed HPV16 E6/E7-expressing primary human foreskin keratinocytes (HFKs) (E6/E7 cells) demonstrate increased expression of the PRC2 methyltransferase EZH2 at both the mRNA and protein levels but do not exhibit the expected increase in trimethylated H3K27 (H3K27me3) compared to normal keratinocytes. In contrast, these cells show a reduction in global H3K27me3 levels in vitro, as well as upregulation of the KDM6A demethylase. We further show for the first time that transformation with the HPV16 E6 and E7 oncogenes also results in an increase in phosphorylated EZH2 serine 21 (P-EZH2-Ser21), mediated by active Akt, and in a downregulation of the PRC1 protein BMI1 in these cells. High-grade squamous cervical intraepithelial lesions also showed a loss of H3K27me3 in the presence of increased expression of EZH2. Correlating with the loss of H3K27me3, E6/E7 cells exhibited derepression of specific EZH2-, KMD6A-, and BMI1-targeted HOX genes. These results suggest that the observed reduction in H3K27me3 may be due to a combination of reduced activities/levels of specific polycomb proteins and increases in demethylases. The dysregulation of multiple chromatin proteins resulting in the loss of global H3K27me3 and the transcriptional reprogramming in HPV16 E6/E7-infected cells could provide an epigenetic signature associated with risk and/or progression of HPV16-associated cancers, as well as the potential for epigenetic reversion in the future. PMID:21865393
Hyland, Paula L; McDade, Simon S; McCloskey, Rachel; Dickson, Glenda J; Arthur, Ken; McCance, Dennis J; Patel, Daksha
2011-11-01
234
PubMed
Marek's disease (MD) is an economically significant disease in chickens that is caused by the highly oncogenic Marek's disease virus (MDV). A major unanswered question is the mechanism of MDV-induced tumor formation. Meq, a bZIP transcription factor discovered in the 1990s, is critically involved in viral oncogenicity, but only a few of its host target genes have been described, impeding our understanding of MDV-induced tumorigenesis. Using chromatin immunoprecipitation-sequencing (ChIP-seq) and microarray analysis, a high-confidence list of Meq binding sites in the chicken genome and a global transcriptome of Meq-responsive genes were generated. Meq binding sites were found to be enriched in the promoter regions of upregulated genes but not in those of downregulated genes. ChIP-seq was also performed for c-Jun, a known heterodimeric partner of Meq. The close location of binding sites of Meq and c-Jun was noted, suggesting cooperativity between these two factors in modulating transcription. Pathway analysis indicated that Meq transcriptionally regulates many genes that are part of several signaling pathways including the extracellular signal-regulated kinase /mitogen-activated protein kinase (ERK/MAPK), Jak-STAT, and ErbB pathways, which are critical for oncogenesis and/or include signaling mediators involved in apoptosis. Meq activates oncogenic signaling cascades by transcriptionally activating major kinases in the ERK/MAPK pathway and simultaneously repressing phosphatases, as verified using inhibitors of MEK and ERK1/2 in a cell proliferation assay. This study provides significant insights into the mechanistic basis of Meq-dependent cell transformation. PMID:23740999
Subramaniam, Sugalesini; Johnston, John; Preeyanon, Likit; Brown, C Titus; Kung, Hsing-Jien; Cheng, Hans H
2013-08-01
235
SciTech Connect
The oncogenic potential of the HTLV-1 Tax protein involves activation of the NF-{kappa}B pathway, which depends on Tax phosphorylation, ubiquitination and sumoylation. We demonstrate that the nuclei of Tax-expressing cells, including HTLV-1 transformed T-lymphocytes, contain a pool of Tax molecules acetylated on lysine residue at amino acid position 346 by the transcriptional coactivator p300. Phosphorylation of Tax on serine residues 300/301 was a prerequisite for Tax localization in the nucleus and correlated with its subsequent acetylation by p300, whereas sumoylation, resulting in the formation of Tax nuclear bodies in which p300 was recruited, favored Tax acetylation. Overexpression of p300 markedly increased Tax acetylation and the ability of a wild type HTLV-1 provirus, -but not of a mutant provirus carrying an acetylation deficient Tax gene-, to activate gene expression from an integrated NF-{kappa}B-controlled promoter. Thus, Tax acetylation favors NF-{kappa}B activation and might play an important role in HTLV-1-induced cell transformation.
Lodewick, Julie; Lamsoul, Isabelle; Polania, Angela; Lebrun, Sylvie [Institute for Microbiological Research J-M Wiame and Laboratory of Microbiology, Universite Libre de Bruxelles, 1, Avenue Emile Gryson, B-1070 Brussels (Belgium); Burny, Arsene [Faculte des Sciences Agronomiques de Gembloux, Gembloux (Belgium); Ratner, Lee [Division of Molecular Oncology, Washington University School of Medicine, St Louis (United States); Bex, Francoise [Institute for Microbiological Research J-M Wiame and Laboratory of Microbiology, Universite Libre de Bruxelles, 1, Avenue Emile Gryson, B-1070 Brussels (Belgium)], E-mail: [email protected]
2009-03-30
236
PubMed Central
A large proportion of vaginal and vulvar squamous cell carcinomas (SCCs) and intraepithelial neoplasias (VAIN and VIN) are associated with HPV infection, mainly type 16. The purpose of this study was to identify HPV genotypes, as well as E6/E7 mRNA expression of high-risk HPVs (16, 18, 31, 33, and 45) in 56 histology samples of VAIN, VIN, vaginal, and vulvar SCCs. HPV was identified in 56% of VAIN and 50% of vaginal SCCs, 71.4% of VIN and 50% of vulvar SCCs. E6/E7 mRNA expression was found in one-third of VAIN and in all vaginal SCCs, 42.9% of VIN and 83.3% of vulvar SCCs. Our data indicated that HPV 16 was the commonest genotype identified in VAIN and VIN and the only genotype found in SCCs of the vagina and vulva. These findings may suggest, in accordance with other studies, that mRNA assay might be useful in triaging lesions with increased risk of progression to cancer. PMID:22187556
Tsimplaki, Elpida; Argyri, Elena; Michala, Lina; Kouvousi, Maria; Apostolaki, Aikaterini; Magiakos, George; Papassideri, Issidora; Panotopoulou, Efstathia
2012-01-01
237
PubMed
As iron ions may participate in the pathogenesis of cancer and viral infections, the aim of this study was to monitor their influence on proliferation, E6 and E7 oncogene expression and reactive oxygen species (ROS) production in two human papilloma virus (HPV) positive cervical carcinoma cell lines (HeLa and SiHa) and one HPV negative vulvar cell line (A431). The anti-anaemic drug, ferric-sorbitol-citric acid complex (FSC) as a source of Fe(III) ions was used. Cells were treated with FSC at the concentrations between 0.001 and 1 mM Fe(III) for different time periods. Fe(III) ions inhibited the viability of HeLa and A431 cells while it had no influence on SiHa cells. Furthermore, Fe(III) treatment showed a time-dependent and a higher stimulatory effect on E6/E7 expression in SiHa cells than in HeLa cells. Fe(III) ion treatment with concentrations lower than 0.1mM showed a time and a concentration dependent intracellular ROS production in all tested cell lines, while the treatment with 1mM concentration decreased ROS production in all tested cell lines. In conclusion, Fe(III) ion treatment apart from having an anti-tumour effect, as we previously described, enhances survival of HPV 16-positive cells and might be associated with HPV oncogenesis. PMID:21044880
Poljak-Blazi, Marija; Jaganjac, Morana; Sabol, Ivan; Mihaljevic, Branka; Matovina, Mihaela; Grce, Magdalena
2011-02-01
238
PubMed Central
The myeloperoxidase (MPO) and neutrophil elastase genes are expressed specifically in immature myeloid cells. The integrity of a polyomavirus enhancer core sequence, 5'-AACCACA-3', is critical to the activity of the murine MPO proximal enhancer. This element binds two species, myeloid nuclear factors 1 alpha and 1 beta (MyNF1 alpha and -beta), present in 32D cl3 myeloid cell nuclear extracts. The levels of the MyNF1s increase during early 32D cl3 cell granulocytic differentiation. Both MyNF1 alpha and -beta supershift with an antiserum raised by using a peptide derived from the N terminus of polyomavirus enhancer-binding protein 2/core-binding factor (PEBP2/CBF) alpha subunit. The specific peptide inhibits these supershifts. In vitro-translated PEBP2/CBF DNA-binding domain binds the murine MPO PEBP2/CBF site. An alternate PEBP2/CBF consensus site, 5'-GACCGCA-3', but not a simian virus 40 enhancer core sequence, 5'-TTCCACA-3', binds the MyNF1s in vitro and activates a minimal murine MPO-thymidine kinase promoter in vivo. The murine neutrophil elastase gene 100-bp 5'-flanking sequences contain several functional elements, including potential binding sites for PU.1, C/EBP, c-Myb, and PEBP2/CBF. The functional element 5'-GGCCACA-3' located at positions -66 to 72 differs from the PEBP2/CBF consensus (5'-PuACCPuCA-3') only by an A-to-G transition at position 2. This DNA element binds MyNF1 alpha and -beta weakly. The N terminis of two PEBP2/CBF alpha subunit family members, PEBP2 alpha A and PEBP2 alpha B (murine AML1), are nearly identical, and 32D c13 cl3 cells contain both corresponding mRNAs. Since t(8;21), t(3;21), and inv(16), associated with myeloid leukemias, disrupt subunits of PEBP2/CBF, we speculate that the resulting oncoproteins, AML1-ETO, AML1-EAP, AML1-Evi1, and CBF beta-MYH11, inhibit early myeloid differentiation. Images PMID:8035830
Nuchprayoon, I; Meyers, S; Scott, L M; Suzow, J; Hiebert, S; Friedman, A D
1994-01-01
239
PubMed
Imatinib, the first-generation tyrosine kinase inhibitor, revolutionized the therapeutic management of chronic myeloid leukemia (CML) and is highly effective in inducing remissions and prolonging the survival of CML patients. However, one-third of patients develop intolerance or resistance to treatment, and CML stem cells remain insensitive to this therapy, leading almost inevitably to relapse upon treatment discontinuation. Imidazoquinoxalines are imiquimod derivatives that induce growth inhibition and induction of caspase-dependent apoptosis in melanoma and T-cell lymphoma cells. We investigated the effects of EAPB0203 and EAPB0503, two novel imidazoquinoxaline derivatives, on human CML cell lines and showed that they induced a dose-dependent and time-dependent cell growth inhibition. EAPB0503 proved more potent and induced a specific cell cycle arrest in mitosis in CML cells and direct activation of apoptosis as evidenced by increased pre-G0 population, breakdown of mitochondrial membrane potential, PARP cleavage, and DNA breakage. Interestingly, EAPB0503 decreased BCR-ABL oncoprotein levels. The combination of EAPB0503 with imatinib synergized to inhibit the proliferation of CML cells, and most importantly, EABP0503 inhibited the proliferation of imatinib-resistant CML cells, offering promising therapeutic modalities that would circumvent resistance to tyrosine kinase inhibitors and improve the prognosis of CML. PMID:24463483
Saliba, Jessica; Deleuze-Masquéfa, Carine; Iskandarani, Ahmad; El Eit, Rabab; Hmadi, Raed; Mahon, François-Xavier; Bazarbachi, Ali; Bonnet, Pierre-Antoine; Nasr, Rihab
2014-07-01
240
PubMed Central
Detection of human papillomavirus (HPV) E6/E7 oncogene expression may be more predictive of cervical cancer risk than testing for HPV DNA. The Aptima HPV test (Gen-Probe) detects E6/E7 mRNA of 14 oncogenic types. Its clinical performance was compared with that of the Hybrid Capture 2 DNA test (HC2; Qiagen) in women referred for colposcopy and those routinely screened. Aptima was also compared with the PreTect HPV-Proofer E6/E7 mRNA assay (Proofer; Norchip) in the referral population. Cervical specimens collected in PreservCyt (Hologic Inc.) were processed for HPV detection and genotyping with the Linear Array (LA) method (Roche Molecular Diagnostics, Laval, Quebec, Canada). Histology-confirmed high-grade cervical intraepithelial neoplasia (CIN 2) or worse (CIN 2+) served as the disease endpoint. On the basis of 1,418 referral cases (CIN 2+, n = 401), the sensitivity of Aptima was 96.3% (95% confidence interval [CI], 94.4, 98.2), whereas it was 94.3% (95% CI, 92.0, 96.6) for HC2. The specificities were 43.2% (95% CI, 40.2, 46.2) and 38.7% (95% CI, 35.7, 41.7), respectively (P < 0.05). In 1,373 women undergoing routine screening (CIN 2+, n = 7), both Aptima and HC2 showed 100% sensitivity, and the specificities were 88.3% (95% CI, 86.6, 90.0) and 85.3% (95% CI, 83.5, 87.3), respectively (P < 0.05); for women ?30 years of age (n = 845), the specificities were 93.9% (95% CI, 92.3, 95.5) and 92.1% (95% CI, 90.3, 93.9), respectively (P < 0.05). On the basis of 818 referral cases (CIN 2+, n = 235), the sensitivity of Aptima was 94.9% (95% CI, 92.1, 97.7) and that of Proofer was 79.1% (95% CI, 73.9, 84.3), and the specificities were 45.8% (95% CI, 41.8, 49.8) and 75.1% (95% CI, 71.6, 78.6), respectively (P < 0.05). Both Aptima and Proofer showed a higher degree of agreement with LA genotyping than HC2. In conclusion, the Aptima test is as sensitive as HC2 but more specific for detecting CIN 2+ and can serve as a reliable test for both primary cervical cancer screening and the triage of borderline cytological abnormalities. PMID:21147950
Ratnam, Samuel; Coutlee, Francois; Fontaine, Dan; Bentley, James; Escott, Nicholas; Ghatage, Prafull; Gadag, Veeresh; Holloway, Glen; Bartellas, Elias; Kum, Nick; Giede, Christopher; Lear, Adrian
2011-01-01
241
PubMed Central
Fouier-transform infrared (FTIR) difference spectra of several His-E7 and Val-E11 mutants of sperm whale carbonmonoxymyoglobin were obtained by photodissociation at cryogenic temperatures. The IR absorption of the CO ligand shows characteristic features for each of the mutants, both in the ligand-bound (A) state and in the photodissociated (B) state. For most of the mutants, a single A substate band is observed, which points to the crucial role of the His-E7 residue in determining the A substrate spectrum of the bound CO in the native structure. The fact that some of the mutants show more than one stretch band of the bound CO indicates that the appearance of multiple A substates is not exclusively connected to the presence of His-E7. In all but one mutant, multiple stretch bands of the CO in the photodissociated state are observed; these B substates are thought to arise from discrete positions and/or orientations of the photodissociated ligand in the heme pocket. The red shifts of the B bands with respect to the free-gas frequency indicate weak binding in the heme pocket. The observation of similar red shifts in microperoxidase (MP-8), where there is no residue on the distal side, suggests that the photodissociated ligand is still associated with the heme iron. Photoselection experiments were performed to determine the orientation of the bound ligand with respect to the heme normal by photolyzing small fractions of the sample with linearly polarized light at 540 nm. The resulting linear dichroism in the CO stretch spectrum yielded angles alpha > 20 degrees between the CO molecular axis and the heme normal for all of the mutants. We conclude that the off-axis position of the CO ligand in the native structure does not arise from steric constraints imposed by the distal histidine. There is no clear correlation between the size of the distal residue and the alpha of the CO ligand. PMID:8312483
Braunstein, D. P.; Chu, K.; Egeberg, K. D.; Frauenfelder, H.; Mourant, J. R.; Nienhaus, G. U.; Ormos, P.; Sligar, S. G.; Springer, B. A.; Young, R. D.
1993-01-01
242
PubMed Central
Electron nuclear double resonance (ENDOR) spectroscopy has been used to study protons in nitrosyl horse heart myoglobin (MbNO). (1)H ENDOR spectra were recorded for different settings of the magnetic field. Detailed analysis of the ENDOR powder spectra, using computer simulation, based on the "orientation-selection" principle, leads to the identification of the available protons in the heme pocket. We observe hyperfine interactions of the N(HisF8)-Fe(2+)-N(NO) complex with five protons in axial and with eight protons in the rhombic symmetry along different orientations, including those of the principal axes of the g-tensor. Protons from His-E7 and Val-E11 residues are identified in the two symmetries, rhombic and axial, exhibited by MbNO. Our results indicate that both residues are present inside the heme pocket and help to stabilize one particular conformation. PMID:10733988
Flores, M; Wajnberg, E; Bemski, G
2000-01-01
243
PubMed
Hemoglobin Haná [?63(E7) His-Asn] is an unstable hemoglobin variant that was described in a Czech proband and her sister with Heinz body hemolytic anemia. The mother bearing the same mutation was asymptomatic; nevertheless, all three carriers had the same proportion of the mutant globin chains. Assessment of several erythrocyte antioxidant parameters revealed that both symptomatic children, unlike their asymptomatic mother, had significantly decreased glutathione reductase (GR) activity. Their GR activities were restorable in vitro by flavin adenine dinucleotide. The riboflavin supplementation improved their glutathione metabolism and ameliorated their hemolysis. Pre- and post-treatment assessment of the B(2) vitamers indicated suboptimal pre-treatment vitamin B(2) status in both children. This study provides evidence that partial GR deficiency may alter the clinical manifestation of an unstable hemoglobinopathy. PMID:20692194
Mojzikova, Renata; Dolezel, Petr; Pavlicek, Jiri; Mlejnek, Petr; Pospisilova, Dagmar; Divoky, Vladimir
2010-10-15
244
PubMed
In this study, we examined the potential of cationic nanoparticle - polyethyleneimine-introduced chitosan shell/poly (methyl methacrylate) core nanoparticles (CS-PEI) for siRNA delivery. Initially, DNA delivery was performed to validate the capability of CS-PEI for gene delivery in the human cervical cancer cell line, SiHa. siRNA delivery were subsequently carried out to evaluate the silencing effect on targeted E6 and E7 oncogenes. Physicochemical properties including size, zeta potential and morphology of CS-PEI/DNA and CS-PEI/siRNA complexes, were analyzed. The surface charges and sizes of the complexes were observed at different N/P ratios. The hydrodynamic sizes of the CS-PEI/DNA and CS-PEI/siRNA were approximately 300-400 and 400-500nm, respectively. Complexes were positively charged depending on the amount of added CS-PEI. AFM images revealed the mono-dispersed and spherical shapes of the complexes. Gel retardation assay confirmed that CS-PEI nanoparticles completely formed complexes with DNA and siRNA at a N/P ratio of 1.6. For DNA transfection, CS-PEI provided the highest transfection result. Localization of siRNA delivered through CS-PEI was confirmed by differential interference contrast (DIC) confocal imaging. The silencing effect of siRNA specific to HPV 16 E6/E7 oncogene was examined at 18 and 24h post-transfection. The results demonstrated the capacity of CS-PEI to suppress the expression of HVP oncogenes. PMID:22939347
Saengkrit, Nattika; Sanitrum, Phakorn; Woramongkolchai, Noppawan; Saesoo, Somsak; Pimpha, Nuttaporn; Chaleawlert-Umpon, Saowaluk; Tencomnao, Tewin; Puttipipatkhachorn, Satit
2012-10-15
245
E-print Network
PAPILLOMAVIRUS ONCOPROTEINS Stefan DUENSING 1 * and Karl M¨UNGER 2 * 1 Molecular Virology Program, University-risk human papillomavirus (HPV)-associated anogenital neoplasia. The two HPV-encoded oncoproteins, E6 and E7 carcinogenesis. © 2003 Wiley-Liss, Inc. Human papillomaviruses (HPVs) are small DNA tumor viruses that cause
Dever, Jennifer A.
246
SciTech Connect
Highlights: Black-Right-Pointing-Pointer Metformin induces differentiation in NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces activation of the MEK/ERK signaling pathway in APL cells. Black-Right-Pointing-Pointer Metformin synergizes with ATRA to trigger maturation of NB4 and primary APL cells. Black-Right-Pointing-Pointer Metformin induces the relocalization and degradation of the PML-RAR{alpha} fusion protein. Black-Right-Pointing-Pointer The study may be applicable for new differentiation therapy in cancer treatment. -- Abstract: Recent studies have shown that metformin, a widely used antidiabetic agent, may reduce the risk of cancer development. In this study, we investigated the antitumoral effect of metformin on both acute myeloid leukemia (AML) and acute promyelocytic leukemia (APL) cells. Metformin induced apoptosis with partial differentiation in an APL cell line, NB4, but only displayed a proapoptotic effect on several non-M3 AML cell lines. Further analysis revealed that a strong synergistic effect existed between metformin and all-trans retinoic acid (ATRA) during APL cell maturation and that metformin induced the hyperphosphorylation of extracellular signal-regulated kinase (ERK) in APL cells. U0126, a specific MEK/ERK activation inhibitor, abrogated metformin-induced differentiation. Finally, we found that metformin induced the degradation of the oncoproteins PML-RAR{alpha} and c-Myc and activated caspase-3. In conclusion, these results suggest that metformin treatment may contribute to the enhancement of ATRA-induced differentiation in APL, which may deepen the understanding of APL maturation and thus provide insight for new therapy strategies.
Huai, Lei; Wang, Cuicui; Zhang, Cuiping; Li, Qihui; Chen, Yirui; Jia, Yujiao; Li, Yan; Xing, Haiyan; Tian, Zheng; Rao, Qing; Wang, Min [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)] [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China); Wang, Jianxiang, E-mail: [email protected] [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)] [State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin 300020 (China)
2012-06-08
247
E-print Network
DEK is a biochemically distinct, conserved nonhistone protein that is vital to global heterochromatin integrity. In addition, DEK can be secreted and function as a chemotactic, proinflammatory factor. Here we show that ...
Ploegh, Hidde
248
PubMed Central
Background Human papillomavirus (HPV) testing is included in the cervical cancer screening program in the triage of women with equivocal (ASC-US) or low-grade (LSIL) cytological lesions. These women have an increased risk for developing high grade dysplasia and cancer (CIN2+) compared to women with normal cytology. However, in order to avoid unnecessary follow-up, as well as overtreatment, a high positive predictive value (PPV) of the triage test is important. Methodology/Principal Findings The HPV test PreTect HPV-Proofer, detecting E6/E7 mRNA from the HPV types 16, 18, 31, 33 and 45, is used as triage test together with repeat cytology. PPV data for HPV E6/E7 mRNA testing during the period from January 2006 up to June 2009 are reported. In total, 406 of 2099 women (19.3%) had a positive HPV test result. Of the women with a positive test result and with a histological diagnosis (n?=?347), 243 women had histological high-grade dysplasia or cancer (CIN2+), giving a PPV of 70.0% (95% confidence interval [CI], 65.2%–74.8%). For HPV 16 or HPV 33 positive women above 40 years of age, the PPV was 83.7% (95% CI, 73.3%–94.0%) and 84.6% (95% CI, 65.0%–100.0%) respectively. The PPV of test positive women with HSIL cytology was 94.2% (95% CI, 88.7%–99.7%). Conclusions When the result in triage is HPV mRNA positive, our data suggest direct treatment for women above 40 years of age or for women with a concurrent cytological HSIL diagnosis, contributing to better clinical safety for these women. In addition, by decreasing the time to treatment, thereby reducing the number of recalls, the patient management algorithm will be considerably improved, in turn reducing follow-up costs as well as unnecessary psychological stress among patients. PMID:20856930
Sørbye, Sveinung Wergeland; Fismen, Silje; Gutteberg, Tore; Mortensen, Elin Synnøve
2010-01-01
249
PubMed Central
Cervical lesion grading is critical for effective patient management. A three-tier classification (cervical intraepithelial neoplasia [CIN] grade 1, 2 or 3) based on H&E slide review is widely used. However, for reasons of considerable inter-observer variation in CIN grade assignment and for want of a biomarker validating a three-fold stratification, CAP-ASCCP LAST consensus guidelines recommend a two-tier system: low- or high-grade squamous intraepithelial lesions (LSIL or HSIL). In this study, high-risk HPV E6/E7 and p16 mRNA expression patterns in eighty-six CIN lesions were investigated by RNAscope chromogenic in situ hybridization (CISH). Specimens were also screened by immunohistochemistry for p16INK4a (clone E6H4), and by tyramide-based CISH for HPV DNA. HPV genotyping was performed by GP5+/6+ PCR combined with cycle-sequencing. Abundant high-risk HPV RNA CISH signals were detected in 26/32 (81.3%) CIN 1, 22/22 (100%) CIN 2 and in 32/32 (100%) CIN 3 lesions. CIN 1 staining patterns were typified (67.7% specimens) by abundant diffusely staining nuclei in the upper epithelial layers; CIN 2 lesions mostly (66.7%) showed a combination of superficial diffuse-stained nuclei and multiple dot-like nuclear and cytoplasmic signals throughout the epithelium; CIN 3 lesions were characterized (87.5%) by multiple dot-like nuclear and cytoplasmic signals throughout the epithelial thickness and absence/scarcity of diffusely staining nuclei (trend across CIN grades: P<0.0001). These data are consistent with productive phase HPV infections exemplifying CIN 1, transformative phase infections CIN 3, whereas CIN 2 shows both productive and transformative phase elements. Three-tier data correlation was not found for the other assays examined. The dual discernment of diffuse and/or dot-like signals together with the assay’s high sensitivity for HPV support the use of HPV E6/E7 RNA CISH as an adjunct test for deciding lesion grade when CIN 2 grading may be beneficial (e.g. among young women) or when ‘LSIL vs. HSIL’ assignment is equivocal. PMID:24625757
Evans, Mark F.; Peng, Zhihua; Clark, Kelli M.; Adamson, Christine S.-C.; Ma, Xiao-Jun; Wu, Xingyong; Wang, Hongwei; Luo, Yuling; Cooper, Kumarasen
2014-01-01
250
PubMed
Moon, Jeong; Koh, Sang Seok; Malilas, Waraporn; Cho, Il-Rae; Kaewpiboon, Chutima; Kaowinn, Sirichat; Lee, Keesook; Jhun, Byung Hak; Choi, Young Whan; Chung, Young-Hwa
2014-07-15
251
PubMed
Human T cell leukemia virus type 1 (HTLV-1) Tax-induced persistent activation of the NF-?B pathway is perceived as the primary cause of adult T cell leukemia (ATL), an aggressive leukemia caused by HTLV-1. Although elevated oncoprotein Bcl-3 levels are found in many HTLV-1-infected T cell lines and ATL cells, the role of Bcl-3 in the malignant progression caused by HTLV-1 retrovirus remains poorly understood. We confirmed, in the present study, that the Tax-induced NF-?B activation involves the regulation of Bcl-3. Both knockdown and overexpression of Bcl-3 inhibit the Tax-induced NF-?B activation. Similarly, excessive Bcl-3 inhibits the NF-?B/DNA binding activity and significantly decreases Tax-induced p65 nuclear translocation. The present results demonstrate the pleiotropic roles of Bcl-3 in Tax-induced NF-?B activation and indicate that a balance in the aberrant Bcl-3 expression may be established to play an important role in the maintenance of proliferation and inhibition of apoptosis in HTLV-1-infected and ATL cells. PMID:23135533
Wang, Jinheng; Li, Junying; Huang, Yanmei; Song, Xiangfeng; Niu, Zhiguo; Gao, Zhitao; Wang, Hui
2013-01-01
252
PubMed Central
Cassava (Manihot esculenta) is a eudicotyledonous plant that produces the valine- and isoleucine-derived cyanogenic glucosides linamarin and lotaustralin with the corresponding oximes and cyanohydrins as key intermediates. CYP79 enzymes catalyzing amino acid-to-oxime conversion in cyanogenic glucoside biosynthesis are known from several plants including cassava. The enzyme system converting oxime into cyanohydrin has previously only been identified in the monocotyledonous plant great millet (Sorghum bicolor). Using this great millet CYP71E1 sequence as a query in a Basic Local Alignment Search Tool-p search, a putative functional homolog that exhibited an approximately 50% amino acid sequence identity was found in cassava. The corresponding full-length cDNA clone was obtained from a plasmid library prepared from cassava shoot tips and was assigned CYP71E7. Heterologous expression of CYP71E7 in yeast afforded microsomes converting 2-methylpropanal oxime (valine-derived oxime) and 2-methylbutanal oxime (isoleucine-derived oxime) to the corresponding cyanohydrins, which dissociate into acetone and 2-butanone, respectively, and hydrogen cyanide. The volatile ketones were detected as 2.4-dinitrophenylhydrazone derivatives by liquid chromatography-mass spectrometry. A KS of approximately 0.9 ?m was determined for 2-methylbutanal oxime based on substrate-binding spectra. CYP71E7 exhibits low specificity for the side chain of the substrate and catalyzes the conversion of aliphatic and aromatic oximes with turnovers of approximately 21, 17, 8, and 1 min?1 for the oximes derived from valine, isoleucine, tyrosine, and phenylalanine, respectively. A second paralog of CYP71E7 was identified by database searches and showed approximately 90% amino acid sequence identity. In tube in situ polymerase chain reaction showed that in nearly unfolded leaves, the CYP71E7 paralogs are preferentially expressed in specific cells in the endodermis and in most cells in the first cortex cell layer. In fully unfolded leaves, the expression is pronounced in the cortex cell layer just beside the epidermis and in specific cells in the vascular tissue cortex cells. Thus, the transcripts of the CYP71E7 paralogs colocalize with CYP79D1 and CYP79D2. We conclude that CYP71E7 is the oxime-metabolizing enzyme in cyanogenic glucoside biosynthesis in cassava. PMID:21045121
Jørgensen, Kirsten; Morant, Anne Vinther; Morant, Marc; Jensen, Niels Bjerg; Olsen, Carl Erik; Kannangara, Rubini; Motawia, Mohammed Saddik; Møller, Birger Lindberg; Bak, Søren
2011-01-01
253
PubMed Central
Clinical studies suggest that responses to HPV16 E6E7L2 fusion protein (TA-CIN) vaccination alone are modest, and GPI-0100 is a well-tolerated, potent adjuvant. Here we sought to optimize both the immunogenicity of TA-CIN via formulation with GPI-0100 and treatment of HPV16+ cancer by vaccination after cisplatin chemotherapy. HPV16 neutralizing serum antibody titers, CD4+ T cell proliferative and E6/E7-specific CD8+ T cell responses were significantly enhanced when mice were vaccinated subcutaneously (s.c.) or intramuscularly (i.m.) with TA-CIN formulated with GPI-0100. Vaccination was tested for therapy of mice bearing syngeneic HPV16 E6/E7+ tumors (TC-1) either in the lung or subcutaneously. Mice treated with TA-CIN/GPI-0100 vaccination exhibited robust E7-specific CD8+ T cell responses, which were associated with reduced tumor burden in the lung, whereas mice receiving either component alone were similar to controls. Since vaccination alone was not sufficient for cure, mice bearing s.c. TC-1 tumor were first treated with two doses of cisplatin and then vaccinated. Vaccination with TA-CIN/GPI-0100 i.m. substantially retarded tumor growth and extended survival after cisplatin therapy. Injection of TA-CIN alone, but not GPI-0100, into the tumor (i.t.) was similarly efficacious after cisplatin therapy, but the mice eventually succumbed. However, tumor regression and extended remission was observed in 80% of the mice treated with cisplatin and then intra-tumoral TA-CIN/GPI-0100 vaccination. These mice also exhibited robust E7-specific CD8+ T cell and HPV16 neutralizing antibody responses. Thus formulation of TA-CIN with GPI-0100 and intra-tumoral delivery after cisplatin treatment elicits potent therapeutic responses in a murine model of HPV16+ cancer. PMID:25560237
Peng, Shiwen; Wang, Joshua W.; Karanam, Balasubramanyam; Wang, Chenguang; Huh, Warner K.; Alvarez, Ronald D.; Pai, Sara I.; Hung, Chien-fu; Wu, T. -C.; Roden, Richard B. S.
2015-01-01
254
PubMed
Prothymosin alpha (PTMA) is overexpressed in various human tumors, including hepatocellular carcinoma (HCC). The significance of PTMA overexpression and its underlying mechanism remain unclear. We show here that silencing PTMA sensitizes HCC cells to the kinase inhibitor sorafenib. In contrast, ectopic expression of PTMA induces cell resistance to the drug. While inhibitors targeting JNK, ERK or PI3K reduce PTMA expression, only ERK activation is suppressed by sorafenib. In addition, inhibition of ERK produces a dramatic decrease in both endogenous PTMA level and promoter activation. Ectopic expression of active MKK1/2 considerably induces PTMA expression. We also identify a sorafenib-responsive segment lying 1000-1500-bp upstream of the PTMA transcription start site and observe that it is controlled by c-Myc and ERK. Mutation in the PTMA promoter at the predicted c-Myc binding site and silencing of c-Myc both abrogate sorafenib's effect on PTMA transcription. We also find that silencing PTMA potentiates Bax translocation to mitochondria in response to sorafenib and this is associated with increased cytochrome c release from mitochondria and enhanced caspase-9 activation. These results indicate that PTMA is positively regulated by the oncoprotein c-Myc and protects HCC cells against sorafenib-induced cell death, thus identifying PTMA as a new target for chemotherapy against HCC. PMID:25451688
Lin, Yi-Te; Lu, Hsing-Pang; Chao, Chuck C-K
2015-01-01
255
PubMed
A major agenda for tumor immunology is the generation of specific immune responses leading to the destruction of incipient and frank neoplasia. In this report, we show that a novel HPV16 E7 fusion protein can produce objective therapeutic responses against incipient cervical cancer in genetically engineered mice that express in the cervix the HPV16 early region genes implicated as causative agents in human cervical cancer. Although nonresponsive toward the HPV16 E7 oncoprotein in the CD8+ T-cell compartment by virtue of MHC haplotype, the mice were capable of mounting an induced CD4+ T-cell response against E7, and in addition developed spontaneous anti-E7 antibodies. HPV16/CD4-/- mice showed increased tumor burden indicative of CD4-mediated immune surveillance. Seeking to enhance the CD4 response, we immunized mice bearing incipient cervical cancer with a recombinant protein fusing E7 with a mycobacterial heat shock protein. The incidences of cervical carcinoma and of high-grade dysplasia (CIN 3) were consequently reduced by comparison to control mice. Thus, an HPV16 E7 immunogen holds promise for noninvasive treatment and prevention of human cervical cancer. PMID:15753402
Daniel, Dylan; Chiu, Christopher; Giraudo, Enrico; Inoue, Masahiro; Mizzen, Lee A; Chu, N Randall; Hanahan, Douglas
2005-03-01
256
E-print Network
Scientific American: The Promise of the Blue Revolution (Extended ver... http://www.sciam.com/print_version.cfm?articleID=2B10ECE2-E7F2-... 1 of 2 6/27/2007 10:27 AM June 17, 2007 The Promise of the Blue Revolution ecosystems. The rapid development of aquaculture in recent years has been likened to a "Blue Revolution
257
PubMed Central
Ewing sarcoma family of tumors (ESFT) is an undifferentiated neoplasm of the bone and soft tissue. ESFT is characterized by a specific chromosomal translocation occurring between chromosome 22 and (in most cases) chromosome 11, which generates an aberrant transcription factor, EWS-FLI1. The function of EWS-FLI1 is essential for the maintenance of ESFT cell survival and tumorigenesis. The Hedgehog pathway is activated in several cancers. Oncogenic potential of the Hedgehog pathway is mediated by increasing the activity of the GLI family of transcription factors. Recent evidence suggests that EWS-FLI1 increases expression of GLI1 by an unknown mechanism. Our data from chromatin immunoprecipitation and promoter reporter studies indicated GLI1 as a direct transcriptional target of EWS-FLI1. Expression of EWS-FLI1 in non-ESFT cells increased GLI1 expression and GLI-dependent transcription. We also detected high levels of GLI1 protein in ESFT cell lines. Pharmacological inhibition of GLI1 protein function decreased proliferation and soft agar colony formation of ESFT cells. Our results establish GLI1 as a direct transcriptional target of EWS-FLI1 and suggest a potential role for GLI1 in ESFT tumorigenesis. PMID:19189974
Beauchamp, Elspeth; Bulut, Gulay; Abaan, Ogan; Chen, Kevin; Merchant, Akil; Matsui, William; Endo, Yoshimi; Rubin, Jeffrey S.; Toretsky, Jeffrey; Üren, Aykut
2009-01-01
258
PubMed
Oncoprotein Bcl-3 is perceived as an unusual member of I?B family since it can both stimulate and suppress NF-?B activation. Aberrant Bcl-3 results in increased cell proliferation and survival, suggesting a contribution to malignant potential and elevated levels of Bcl-3 have been observed in many HTLV-1-infected T cell lines and ATL cells. To investigate the specific roles of Bcl-3 in HTLV-1-infected cells, we knocked down Bcl-3 expression using shRNA and then examined the consequences with regard to DNA damage and cell proliferation, as well as NF-?B activation. The HTLV-1 encoded protein Tax promotes Bcl-3 expression and nuclear translocation. In HTLV-1-infected cells, Bcl-3 knockdown obviously induced DNA damage. Cell growth and NF-?B activation were reduced in HTLV-1-infected or Tax positive cells when Bcl-3 expression was decreased. Together, our results revealed positive roles of Bcl-3 in DNA stabilization, growth and NF-?B activation in HTLV-1-infected cells. PMID:23534762
Gao, Cai; Wang, Xia; Chen, Lin; Wang, Jin-Heng; Gao, Zhi-Tao; Wang, Hui
2013-01-01
259
PubMed Central
Tumor metastasis is a complex phenomenon that is the culmination of effects of numerous cellular factors. We have shown that the EBV oncoprotein, latent membrane protein 1 (LMP1), is capable of inducing a wide range of such factors in cell culture, expression of which is also elevated in the LMP1-expressing tumor, nasopharyngeal carcinoma (NPC), a highly invasive neoplasm. Recently, the membrane-crosslinker protein ezrin has been implicated in tumor cell metastasis and malignant progression. In this study, we evaluated the possible role of LMP1 and ezrin in the pathophysiology of NPC. We show that C-terminal phosphorylation of ezrin is increased by expression of LMP1 in nasopharyngeal (NP) cells through a Protein Kinase C (PKC) pathway. LMP1 enhances organization of a ternary complex of CD44, ezrin and F-actin which is a prerequisite for ezrin phosphorylation. In NPC tissues, expression of phosphoezrin and LMP1 is directly correlated. Silencing of endogenously expressed ezrin suppresses LMP1-induced cell motility and invasiveness. Moreover inhibition of ezrin phosphorylation by PKC inhibitor suppresses migration and invasion of NP cells. These data demonstrate that phosphorylation of ezrin and its recruitment to the cell membrane linked to F-actin and CD44 is a process required for LMP1-stimulated cell motility and invasion of NP cells. PMID:19234486
Endo, Kazuhira; Kondo, Satoru; Shackleford, Julia; Horikawa, Toshiyuki; Kitagawa, Noriko; Yoshizaki, Tomokazu; Furukawa, Mitsuru; Zen, Yoh; Pagano, Joseph S.
2009-01-01
260
PubMed
ATM kinase (ATM) is essential for activation of cell cycle check points and DNA repair in response to ionizing radiation (IR). In this work we studied the molecular mechanisms regulating DNA repair and cell death in human T-lymphocyte leukemic cells, MOLT-4. Apoptosis was evaluated by flow-cytometric detection of annexin V. Early apoptotic cells were determined as sub-G1 cells and late apoptotic cells were determined as APO2.7-positive ones. Proteins involved in ATM signalling pathway were analysed by Western-blotting. We observed a rapid (0.5 h) phosphorylation of ATM declining after 6 h after irradiation by all the doses studied (1.5, 3.0, and 7.5 Gy). Checkpoint kinase-2 (Chk-2) was also phosphorylated after 0.5 h but its phosphorylated form persisted 4, 2, and 1 h after the doses of 1.5, 3.0, and 7.5 Gy, respectively. The amount of p53 protein and its form phosphorylated on Ser-392 increased 1 h after irradiation (1-10 Gy). The lethal dose of 7.5 Gy caused an immediate induction and phosphorylation of p53 after 0.5 h post-irradiation. At the time of phosphorylation of p53, we found simultaneous phosphorylation of the oncoprotein Mdm2 on Ser-166. Neither ATM nor its downstream targets showed a dose-dependent response after 1 h when irradiated by the doses of 1-10 Gy. MOLT-4 cells were very sensitive to the effect of IR. Even low doses, such as 1.5 Gy, induced apoptosis 16 h after irradiation (evaluated according to the cleavage of nuclear lamin B to a 48-kDa fragment). IR-induced molecular signalling after exposure to all the tested doses was triggered by rapid phosphorylation of ATM and Chk-2. Subsequent induction of p53 protein and its phosphorylation was accompanied by concomitant phosphorylation of its negative regulator, oncoprotein Mdm2, and followed by induction of apoptosis. PMID:17565390
Tichý, Ales; Záskodová, Darina; Rezácová, Martina; Vávrová, Jirina; Vokurková, Doris; Pejchal, Jaroslav; Vilasová, Zdena; Cerman, Jaroslav; Osterreicher, Jan
2007-01-01
261
PubMed Central
ABSTRACT The cancer-causing high-risk human papillomavirus (HPV) E6 oncoproteins target a number of cellular proteins that contain PDZ domains. However, the role of many of these interactions in either the HPV life cycle or in HPV-induced malignancy remains to be defined. Previous studies had shown that MAGI-1 was one of the most strongly bound PDZ domain-containing substrates of E6, and one consequence of this interaction appeared to facilitate the perturbation of tight junctions (TJs) by E6. In this study, we describe the generation of a mutation, K499E, within the MAGI-1 PDZ1 domain, which is resistant to E6 targeting. This mutant allows restoration of MAGI-1 expression in HPV-positive cells and defines additional activities of MAGI-1 that are overcome as a consequence of the association with E6. The reexpression of MAGI-1 in HPV-positive cells results in an increased recruitment of ZO-1 and PAR3 to sites of cell-cell contact, repression of cell proliferation, and induction of apoptosis. While the K499E mutation does not significantly affect these intrinsic activities of MAGI-1 in HPV-negative cells, its resistance to E6 targeting in an HPV-positive setting results in more cells expressing the mutant MAGI-1 than the wild-type MAGI-1, with a corresponding increase in TJ assembly, induction of apoptosis, and reduction in cell proliferation. These studies provide compelling evidence of a direct role for the perturbation of MAGI-1 function by E6 in the HPV life cycle and in HPV-induced malignancy. IMPORTANCE It is clear that the targeting of PDZ-containing substrates by E6 is important for the normal viral life cycle and for the progression to malignancy. Nevertheless, which of these PDZ domain-containing proteins is relevant for HPV pathology is still elusive. In a previous study, we provided evidence that MAGI-1 is a sensitive proteolytic substrate for both the HPV-16 and HPV-18 E6 oncoproteins; however, the biological consequences associated with loss of MAGI-1 expression in HPV-positive cervical cancer cells are still poorly understood. Using a mutant MAGI-1, resistant to E6-mediated degradation, we show that its expression in cervical cancer cells promotes membrane recruitment of the tight junction-associated proteins ZO-1 and PAR3, represses cell proliferation, and promotes apoptosis. These findings suggest that E6-mediated inhibition of MAGI-1 function contributes to HPV pathology by perturbing tight junction assembly with concomitant stimulation of proliferation and inhibition of apoptosis. PMID:24696483
Kranjec, Christian; Massimi, Paola
2014-01-01
262
PubMed
Tumor suppressor proteins play a crucial role in cell cycle regulation. Retinoblastoma protein (pRB) is one among them which regulates G1-S transition by binding with transcription factors. The activity of pRB is deregulated by cyclin dependent kinases-mediated hyper-phosphorylation and also due to cancer-derived mutations. In addition, it is also deactivated by binding of viral onco-proteins such as large T antigen, E1A, and E7. These viral proteins initially recognize pRB through their conserved LxCxE motif and facilitate dissociation of preexisting pRB-E2F complex. Based on these features, molecular dynamics (MD) simulation is performed for four different states of pRB for which the crystal structure is available. The unliganded/apo form and complex forms with E2F and E7 peptides reveal the molecular mechanism behind the activation and inactivation of pRB. In addition, the ternary complex of pRB with both E7 and E2F (for which no crystal structure is available) is modeled and simulated to understand the influence of binding of one ligand on the other. The variations in the three major factors such as conformational changes, inter- and intra-molecular interactions, and binding free energies between the apo and complex forms confirm the possibility for designing a small molecule inhibitor to inhibit pRB-E7 interactions without altering the prebound E2F. The present study deals with the molecular modeling and MD simulations of pRB in free and ligand-bound forms and confirms that pRB could be a valid target for the anticancer drug design when the cancer is induced by the viral onco-proteins and forms a clear base for designing E7 antagonists. PMID:23157310
Ramakrishnan, C; Subramanian, V; Balamurugan, K; Velmurugan, D
2013-01-01
263
PubMed Central
Myc oncoproteins and histone deacetylases (HDACs) exert oncogenic effects by modulating gene transcription. Paradoxically, N-Myc induces p53 gene expression. Tumor protein 53-induced nuclear protein 1 (TP53INP1) phosphorylates p53 protein at serine 46, leading to enhanced p53 activity, transcriptional activation of p53 target genes and programmed cell death. Here we aimed to identify the mechanism through which N-Myc overexpressing p53 wild-type neuroblastoma cells acquired resistance to apoptosis. TP53INP1 was found to be one of the genes most significantly repressed by HDAC2 and N-Myc according to Affymetrix microarray gene expression datasets. HDAC2 and N-Myc reduced TP53INP1 gene expression by direct binding to the TP53INP1 gene promoter, leading to transcriptional repression of TP53INP1, p53 protein de-phosphorylation at serine 46, neuroblastoma cell proliferation and survival. Moreover, low levels of TP53INP1 expression in human neuroblastoma tissues correlated with high levels of N-Myc expression and poor patient outcome, and the BET bromodomain inhibitors JQ1 and I-BET151 reduced N-Myc expression and reactivated TP53INP1 expression in neuroblastoma cells. These findings identify TP53INP1 repression as an important co-factor for N-Myc oncogenesis, and provide further evidence for the potential application of BET bromodomain inhibitors in the therapy of N-Myc-induced neuroblastoma. PMID:24952595
Shahbazi, Jeyran; Scarlett, Christopher J.; Norris, Murray D.; Liu, Bing; Haber, Michelle; Tee, Andrew E.; Carrier, Alice; Biankin, Andrew V.; London, Wendy B.; Marshall, Glenn M.; Lock, Richard B.; Liu, Tao
2014-01-01
264
PubMed
Myc oncoproteins and histone deacetylases (HDACs) exert oncogenic effects by modulating gene transcription. Paradoxically, N-Myc induces p53 gene expression. Tumor protein 53-induced nuclear protein 1 (TP53INP1) phosphorylates p53 protein at serine 46, leading to enhanced p53 activity, transcriptional activation of p53 target genes and programmed cell death. Here we aimed to identify the mechanism through which N-Myc overexpressing p53 wild-type neuroblastoma cells acquired resistance to apoptosis. TP53INP1 was found to be one of the genes most significantly repressed by HDAC2 and N-Myc according to Affymetrix microarray gene expression datasets. HDAC2 and N-Myc reduced TP53INP1 gene expression by direct binding to the TP53INP1 gene promoter, leading to transcriptional repression of TP53INP1, p53 protein de-phosphorylation at serine 46, neuroblastoma cell proliferation and survival. Moreover, low levels of TP53INP1 expression in human neuroblastoma tissues correlated with high levels of N-Myc expression and poor patient outcome, and the BET bromodomain inhibitors JQ1 and I-BET151 reduced N-Myc expression and reactivated TP53INP1 expression in neuroblastoma cells. These findings identify TP53INP1 repression as an important co-factor for N-Myc oncogenesis, and provide further evidence for the potential application of BET bromodomain inhibitors in the therapy of N-Myc-induced neuroblastoma. PMID:24952595
Shahbazi, Jeyran; Scarlett, Christopher J; Norris, Murray D; Liu, Bing; Haber, Michelle; Tee, Andrew E; Carrier, Alice; Biankin, Andrew V; London, Wendy B; Marshall, Glenn M; Lock, Richard B; Liu, Tao
2014-06-30
265
PubMed Central
The Helicobacter pylori CagA bacterial oncoprotein plays a critical role in gastric carcinogenesis. Upon delivery into epithelial cells, CagA causes loss of polarity and activates aberrant Erk signaling. We show that CagA-induced Erk activation results in senescence and mitogenesis in nonpolarized and polarized epithelial cells, respectively. In nonpolarized epithelial cells, Erk activation results in oncogenic stress, up-regulation of the p21Waf1/Cip1 cyclin-dependent kinase inhibitor, and induction of senescence. In polarized epithelial cells, CagA-driven Erk signals prevent p21Waf1/Cip1 expression by activating a guanine nucleotide exchange factor–H1–RhoA–RhoA-associated kinase–c-Myc pathway. The microRNAs miR-17 and miR-20a, induced by c-Myc, are needed to suppress p21Waf1/Cip1 expression. CagA also drives an epithelial-mesenchymal transition in polarized epithelial cells. These findings suggest that CagA exploits a polarity-signaling pathway to induce oncogenesis. PMID:20855497
Saito, Yasuhiro; Murata-Kamiya, Naoko; Hirayama, Toshiya; Ohba, Yusuke
2010-01-01
266
PubMed
BRAF mutations are associated with aggressive, less-differentiated and therapy-resistant colorectal carcinoma. However, the underlying mechanisms for these correlations remain unknown. To understand how oncogenic B-Raf contributes to carcinogenesis, in particular to aspects other than cellular proliferation and survival, we generated three isogenic human colorectal carcinoma cell line models in which we can dynamically modulate the expression of the B-Raf(V600E) oncoprotein. Doxycyclin-inducible knockdown of endogenous B-Raf(V600E) decreases cellular motility and invasion in conventional and three-dimensional (3D) culture, whereas it promotes cell-cell contacts and induces various hallmarks of differentiated epithelia. Importantly, all these effects are recapitulated by B-Raf (PLX4720, vemurafenib, and dabrafenib) or MEK inhibitors (trametinib). Surprisingly, loss of B-Raf(V600E) in HT29 xenografts does not only stall tumor growth, but also induces glandular structures with marked expression of CDX2, a tumor-suppressor and master transcription factor of intestinal differentiation. By performing the first transcriptome profiles of PLX4720-treated 3D cultures of HT29 and Colo-205 cells, we identify several upregulated genes linked to epithelial differentiation and effector functions, such as claudin-1, a Cdx-2 target gene encoding a critical tight junction component. Thereby, we provide a mechanism for the clinically observed correlation between mutant BRAF and the loss of Cdx-2 and claudin-1. PLX4720 also suppressed several metastasis-associated transcripts that have not been implicated as targets, effectors or potential biomarkers of oncogenic B-Raf signaling so far. Together, we identify a novel facet of clinically applied B-Raf or MEK inhibitors by showing that they promote cellular adhesion and differentiation of colorectal carcinoma cells. Cancer Res; 75(1); 216-29. ©2014 AACR. PMID:25381152
Herr, Ricarda; Köhler, Martin; Andrlová, Hana; Weinberg, Florian; Möller, Yvonne; Halbach, Sebastian; Lutz, Lisa; Mastroianni, Justin; Klose, Martin; Bittermann, Nicola; Kowar, Silke; Zeiser, Robert; Olayioye, Monilola A; Lassmann, Silke; Busch, Hauke; Boerries, Melanie; Brummer, Tilman
2015-01-01
267
SciTech Connect
Human papillomaviruses (HPV) 16 is a DNA virus encoding three oncogenes - E5, E6, and E7. The E6 and E7 proteins have well-established roles as inhibitors of tumor suppression, but the contribution of E5 to malignant transformation is controversial. Using spontaneously immortalized human keratinocytes (HaCaT cells), we demonstrate that expression of HPV16 E5 is necessary and sufficient for the formation of bi-nucleated cells, a common characteristic of precancerous cervical lesions. Expression of E5 from non-carcinogenic HPV6b does not produce bi-nucleate cells. Video microscopy and biochemical analyses reveal that bi-nucleates arise through cell-cell fusion. Although most E5-induced bi-nucleates fail to propagate, co-expression of HPV16 E6/E7 enhances the proliferation of these cells. Expression of HPV16 E6/E7 also increases bi-nucleated cell colony formation. These findings identify a new role for HPV16 E5 and support a model in which complementary roles of the HPV16 oncogenes lead to the induction of carcinogenesis.
Hu Lulin; Plafker, Kendra [Department of Cell Biology, University of Oklahoma (United States); Vorozhko, Valeriya [Department of Cell Biology, University of Oklahoma (United States); Cell Cycle and Cancer Biology Research Program, Oklahoma Medical Research Foundation (United States); Zuna, Rosemary E. [Department of Pathology, University of Oklahoma HSC (United States); Hanigan, Marie H. [Department of Cell Biology, University of Oklahoma (United States); Gorbsky, Gary J. [Department of Cell Biology, University of Oklahoma (United States); Cell Cycle and Cancer Biology Research Program, Oklahoma Medical Research Foundation (United States); Plafker, Scott M. [Department of Cell Biology, University of Oklahoma (United States); Angeletti, Peter C. [Nebraska Center for Virology (United States); Ceresa, Brian P. [Department of Cell Biology, University of Oklahoma (United States)], E-mail: [email protected]
2009-02-05
268
PubMed Central
Although HPV-DNA test and E6/E7 mRNA analyses remain the current standard for the confirmation of human papillomavirus (HPV) infections in cytological specimens, no universally adopted techniques exist for the detection of HPV in formalin-fixed paraffin-embedded samples. Particularly, in routine laboratories, molecular assays are still time-consuming and would require a high level of expertise. In this study, we investigated the possible use of a novel HPV tyramide-based chromogenic in situ hybridization (CISH) technology to locate HPV on tissue specimens. Then, we evaluate the potential usefulness of p16INK4a/Ki-67 double stain on histological samples, to identify cervical cells expressing HPV E6/E7 oncogenes. In our series, CISH showed a clear signal in 95.2% of the specimens and reached a sensitivity of 86.5%. CISH positivity always matched with HPV-DNA positivity, while 100% of cases with punctated signal joined with cervical intraepithelial neoplasia grade 2 or worse (CIN2+). p16/Ki67 immunohistochemistry gave an interpretable result in 100% of the cases. The use of dual stain significantly increased the agreement between pathologists, which reached 100%. Concordance between dual stain and E6/E7 mRNA test was 89%. In our series, both CISH and p16INK4a/Ki67 dual stain demonstrated high grade of performances. In particular, CISH would help to distinguish episomal from integrated HPV, in order to allow conclusions regarding the prognosis of the lesion, while p16INK4a/Ki67 dual stain approach would confer a high level of standardization to the diagnostic procedure. PMID:24369532
Zappacosta, Roberta; Colasante, Antonella; Viola, Patrizia; D'Antuono, Tommaso; Lattanzio, Giuseppe; Capanna, Serena; Gatta, Daniela Maria Pia; Rosini, Sandra
2013-01-01
269
PubMed
Rate constants for the gas-phase reactions of OH radicals with the C(7)-C(14) 1-alkenes and with E-7-tetradecene and 2-methyl-1-tridecene have been measured at 295 +/- 1 K and atmospheric pressure of air using a relative rate technique. The rate constants obtained (in units of 10(-11) cm(3) molecule(-1) s(-1)) were: 1-heptene, 3.86 +/- 0.12; 1-octene, 4.14 +/- 0.08; 1-nonene, 4.32 +/- 0.05; 1-decene, 4.61 +/- 0.14; 1-undecene, 4.79 +/- 0.11; 1-dodecene, 5.03 +/- 0.13; 1-tridecene, 5.09 +/- 0.17; 1-tetradecene, 4.96 +/- 0.28; E-7-tetradecene, 7.47 +/- 0.53; and 2-methyl-1-tridecene, 8.69 +/- 0.27, where the indicated errors are two least-squares standard deviations and do not include the uncertainty associated with the rate constant for the reference compound alpha-pinene. While our rate constants for 1-octene and 1-nonene agree with those at 298 K recently measured using an absolute rate method, our rate constants for 1-decene and 1-undecene are lower by factors of 1.5 and 2.6, respectively. Combined with previous rate constants from this laboratory for the C(4)-C(7) 1-alkenes, our data show that the rate constants for the reactions of OH radicals with 1-alkenes increase linearly with increasing carbon number, with the increase per additional CH(2) group being a factor of approximately 1.4-1.5 higher than that observed in the n-alkane series. The rate constants measured for E-7-tetradecene and 2-methyl-1-tridecene suggest that the increase in rate constant per additional CH(2) group ranges from being similar to that in the n-alkanes series to being a factor of approximately 2 higher. PMID:18612520
Aschmann, Sara M; Atkinson, Roger
2008-07-28
270
ERIC Educational Resources Information Center
Induced probabilities have been largely ignored by educational researchers. Simply stated, if a new or random variable is defined in terms of a first random variable, then induced probability is the probability or density of the new random variable that can be found by summation or integration over the appropriate domains of the original random…
Neel, John H.
271
PubMed Central
Park, Eun Kyung; Bae, Su-Mi; Kwak, Sun-Young; Lee, Sung Jong; Kim, Yong-Wook; Han, Chan-Hee; Cho, Hyun-Jung; Kim, Kyung Tae; Kim, Young-Jae; Kim, Hyun-Jung; Ahn, Woong Shick
2008-01-01
272
PubMed Central
CAAT/enhancer binding proteins (C/EBPs) are transcriptional activators implicated in the differentiation processes of various cell lineages. We have shown earlier that NF-M, the chicken homolog of C/EBP beta, is specifically expressed in myelomonocytic and eosinophilic cells of the hematopoietic system. To investigate the role of NF-M in hematopoietic cell lineage commitment, we constructed a conditional form of the protein by fusing it to the hormone binding domain of the human estrogen receptor. This construct was stably expressed in a multipotent progenitor cell line transformed by the Myb-Ets oncoprotein. We report here that both NF-M-dependent promoter constructs and resident genes could be activated by addition of beta-estradiol to the NF-M-estrogen receptor expressing progenitors. At the same time, we observed a down-regulation of progenitor-specific surface markers and the up-regulation of differentiation markers restricted to the eosinophil and myeloid lineages. In addition to the onset of differentiation, cell death was induced with typical apoptotic features. Our results suggest that NF-M plays an important role in commitment along the eosinophil lineage and in the induction of apoptosis. Images PMID:8557032
Müller, C; Kowenz-Leutz, E; Grieser-Ade, S; Graf, T; Leutz, A
1995-01-01
273
PubMed Central
Fulvestrant is a representative pure antiestrogen and a Selective Estrogen Receptor Down-regulator (SERD). In contrast to the Selective Estrogen Receptor Modulators (SERMs) such as 4-hydroxytamoxifen that bind to estrogen receptor ? (ER?) as antagonists or partial agonists, fulvestrant causes proteasomal degradation of ER? protein, shutting down the estrogen signaling to induce proliferation arrest and apoptosis of estrogen-dependent breast cancer cells. We performed genome-wide RNAi knockdown screenings for protein kinases required for fulvestrant-induced apoptosis of the MCF-7 estrogen-dependent human breast caner cells and identified the c-Src tyrosine kinase (CSK), a negative regulator of the oncoprotein c-Src and related protein tyrosine kinases, as one of the necessary molecules. Whereas RNAi knockdown of CSK in MCF-7 cells by shRNA-expressing lentiviruses strongly suppressed fulvestrant-induced cell death, CSK knockdown did not affect cytocidal actions of 4-hydroxytamoxifen or paclitaxel, a chemotherapeutic agent. In the absence of CSK, fulvestrant-induced proteasomal degradation of ER? protein was suppressed in both MCF-7 and T47D estrogen-dependent breast cancer cells whereas the TP53-mutated T47D cells were resistant to the cytocidal action of fulvestrant in the presence or absence of CSK. MCF-7 cell sensitivities to fulvestrant-induced cell death or ER? protein degradation was not affected by small-molecular-weight inhibitors of the tyrosine kinase activity of c-Src, suggesting possible involvement of other signaling molecules in CSK-dependent MCF-7 cell death induced by fulvestrant. Our observations suggest the importance of CSK in the determination of cellular sensitivity to the cytocidal action of fulvestrant. PMID:23593342
Yeh, Wei-Lan; Shioda, Keiko; Coser, Kathryn R.; Rivizzigno, Danielle; McSweeney, Kristen R.; Shioda, Toshi
2013-01-01
274
PubMed
The polycomb group protein B lymphoma Mo-MLV insertion region 1 homolog (Bmi-1) is dysregulated in various cancers, and its upregulation strongly correlates with an invasive phenotype and poor prognosis in patients with nasopharyngeal carcinomas. However, the underlying mechanism of Bmi-1-mediated invasiveness remains unknown. In the current study, we found that upregulation of Bmi-1 induced epithelial-mesenchymal transition (EMT) and enhanced the motility and invasiveness of human nasopharyngeal epithelial cells, whereas silencing endogenous Bmi-1 expression reversed EMT and reduced motility. Furthermore, upregulation of Bmi-1 led to the stabilization of Snail, a transcriptional repressor associated with EMT, via modulation of PI3K/Akt/GSK-3beta signaling. Chromatin immunoprecipitation assays revealed that Bmi-1 transcriptionally downregulated expression of the tumor suppressor PTEN in tumor cells through direct association with the PTEN locus. This in vitro analysis was consistent with the statistical inverse correlation detected between Bmi-1 and PTEN expression in a cohort of human nasopharyngeal carcinoma biopsies. Moreover, ablation of PTEN expression partially rescued the migratory/invasive phenotype of Bmi-1-silenced cells, indicating that PTEN might be a major mediator of Bmi-1-induced EMT. Our results provide functional and mechanistic links between the oncoprotein Bmi-1 and the tumor suppressor PTEN in the development and progression of cancer. PMID:19884659
Song, Li-Bing; Li, Jun; Liao, Wen-Ting; Feng, Yan; Yu, Chun-Ping; Hu, Li-Juan; Kong, Qing-Li; Xu, Li-Hua; Zhang, Xing; Liu, Wan-Li; Li, Man-Zhi; Zhang, Ling; Kang, Tie-Bang; Fu, Li-Wu; Huang, Wen-Lin; Xia, Yun-Fei; Tsao, Sai Wah; Li, Mengfeng; Band, Vimla; Band, Hamid; Shi, Qing-Hua; Zeng, Yi-Xin; Zeng, Mu-Sheng
2009-12-01
275
PubMed
Chronic myeloid leukaemia (CML) is a myeloproliferative disorder characterized by the presence of Philadelphia chromosome and by BCR-ABL1, which encodes the BCR-ABL oncoprotein. Although imatinib mesylate (IM) is effective for CML treatment, patients in accelerated and blastic phases of the disease are often refractory to this therapy, and there are also cases of IM resistance in patients in the chronic phase. Therefore, potential new drugs are being investigated to improve the efficiency of the therapy of CML such as snake venoms and their compounds. In this investigation, Bothrops pirajai L-amino acid oxidase (BpirLAAO-I) effect on normal peripheral blood mononuclear cells (PBMC) and on BCR-ABL(+) cell line was assessed to explore its potential against leukaemic cells. MTT viability assay, lymphocyte subsets quantification and cell activation markers expression were performed to evaluate BpirLAAO-I effect on normal PBMC. The effect of BpirLAAO-I on HL-60 and HL-60.BCR-ABL cell lines was assessed by apoptosis detection. BpirLAAO-I was able to induce apoptosis in HL-60 and HL-60.BCR-ABL cell lines in a dose-dependent manner, promoted caspases 3, 8 and 9 activation and enhanced IM effect while not affecting the viability of normal cells. In addition, BpirLAAO-I promoted immune cells activation and lymphocytes subsets changes on normal PBMC. The results indicate that BpirLAAO-I induces apoptosis and potentiates IM effect on BCR-ABL(+) cells. PMID:23551499
Burin, Sandra M; Ayres, Lorena R; Neves, Renata P; Ambrósio, Luciana; de Morais, Fabiana R; Dias-Baruffi, Marcelo; Sampaio, Suely V; Pereira-Crott, Luciana S; de Castro, Fabíola A
2013-08-01
276
PubMed
Induced acne belongs to the clinical forms of acne. Some dermatoses present with acne-like patterns. They can be induced or perpetuated by non physiological factors. Among these factors, medicines must always be considered, taken either topically (dermocorticoids, sulfur, anti-acneic topics) or generally (androgens, oral corticoids, ACTH, anti-epileptics, anti-depressive drugs, anti-tuberculosis medications). Halogens (iodine, bromine) found in inhaled or orally taken pharmaceutical products, or associated with occupational contact, can also induce acne. Acne of exogenous origin has been described in some specific occupations, and are induced by exposure to chlorine, industrial oils, tar. Sun exposure, PUVA therapy and ionizing radiation are potentially acneigenous. Finally acne caused by cosmetics includes acne cosmetica, brilliantine and oily creams acne and detergent acne. PMID:12053790
Humbert, Philippe
2002-04-15
277
SciTech Connect
One of the requirements for tumor growth is the ability to recruit a blood supply, a process known as angiogenesis. Angiogenesis begins early in the progression of cervical disease from mild to severe dysplasia and on to invasive cancer. We have previously reported that expression of human papillomavirus type 16 E6 and E7 (HPV16 E6E7) proteins in primary foreskin keratinocytes (HFKs) decreases expression of two inhibitors and increases expression of two angiogenic inducers [Toussaint-Smith, E., Donner, D.B., Roman, A., 2004. Expression of human papillomavirus type 16 E6 and E7 oncoproteins in primary foreskin keratinocytes is sufficient to alter the expression of angiogenic factors. Oncogene 23, 2988-2995]. Here we report that HPV-induced early changes in the keratinocyte phenotype are sufficient to alter endothelial cell behavior both in vitro and in vivo. Conditioned media from HPV16 E6E7 expressing HFKs as well as from human cervical keratinocytes containing the intact HPV16 were able to stimulate proliferation and migration of human microvascular endothelial cells. In addition, introduction of the conditioned media into immunocompetent mice using a Matrigel plug model resulted in a clear angiogenic response. These novel data support the hypothesis that HPV proteins contribute not only to the uncontrolled keratinocyte growth seen following HPV infection but also to the angiogenic response needed for tumor formation.
Chen, W. [Department of Microbiology and Immunology and the Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, 635 Barnhill Drive, Indianapolis, IN 46202-5120 (United States); Li, F.; Mead, L.; White, H. [Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Walker, J. [Department of Microbiology and Immunology and the Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, 635 Barnhill Drive, Indianapolis, IN 46202-5120 (United States); Ingram, D.A. [Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Roman, A. [Department of Microbiology and Immunology and the Walther Oncology Center, Indiana University School of Medicine and the Walther Cancer Institute, Indianapolis, 635 Barnhill Drive, Indianapolis, IN 46202-5120 (United States)], E-mail: [email protected]
2007-10-10
278
PubMed
Sulforaphane is a cruciferous vegetable-derived isothiocyanate with promising chemopreventive and therapeutic activities. Induction of proliferation arrest and apoptosis principally contribute to sulforaphane's anticancer activity, but the precise molecular mechanisms remain elusive. The oncoprotein SKP2 is a key component of the SKP1-CULLIN1-F-box (SCF) E3 ligase complex and is responsible for directing SCF-mediated degradation of cyclin-dependent kinase inhibitor p27(KIP1) to promote cell proliferation. We herein provide the first evidence supporting the critical involvement of the SKP2-p27(KIP1) axis in sulforaphane-induced antiproliferation in various human colon adenocarcinoma cell lines. Specifically, sulforaphane markedly suppressed the levels of bromodeoxyuridine (BrdU) incorporation and clonogenicity in all tested cell lines, illustrating the antiproliferative effect of sulforaphane. Of note, sulforaphane-induced antiproliferation was accompanied with down-regulation of SKP2, leading to the stabilization and thus up-regulation of p27(KIP1). Additionally, sulforaphane was found to down-regulate SKP2 mainly through transcriptional repression, as sulforaphane lowered SKP2 mRNA expression and the SKP2 promoter activity. Furthermore, sulforaphane treatment led to the activation of both AKT and ERK, thus ruling out the possibility that sulforaphane down-regulates SKP2 by inhibiting AKT or ERK. Notably, sulforaphane-elicited suppression of BrdU incorporation and clonogenicity were significantly rescued in the context of SKP2 overexpression or p27(KIP1) depletion, therefore highlighting the important role of SKP2 down-regulation and the ensuing stabilization of p27(KIP1) in sulforaphane-induced antiproliferation. Collectively, these data expand our molecular understanding about how sulforaphane elicits proliferation arrest, but also implicate the application of sulforaphane in therapeutic modalities targeting SKP2. PMID:25070589
Chung, Yuan-Kai; Chi-Hung Or, Richard; Lu, Chien-Hsing; Ouyang, Wei-Ting; Yang, Shu-Yi; Chang, Chia-Che
2015-01-01
279
PubMed
Human papillomavirus (HPV) is established as causative in oropharyngeal squamous cell carcinomas (OSCCs), being detected in 50% to 80% of tumors by DNA in situ hybridization (ISH) and/or polymerase chain reaction. However, these tests do not assess viral transcription. Many consider E6/E7 messenger ribonucleic acid (mRNA) the best indicator of HPV status, but it has not been detected in situ in OSCC. We constructed tissue microarrays (TMAs) from a cohort of OSCC for which p16 immunohistochemistry and HPV DNA ISH were previously performed on whole sections. We utilized a novel, chromogenic RNA ISH assay called RNAscope to detect E6/E7 mRNA of HPV-16 and other high-risk types on these TMAs. RNA ISH results were obtained for 196 of 211 TMA cases, of which 153 (78.1%) were positive. p16 immunohistochemistry and HPV DNA ISH were positive in 79.0% and 62.4% of cases, respectively. Concordance between RNA and p16, DNA and p16, and RNA and DNA were 96.4%, 78.7%, and 83.5%, respectively. Only 7 cases (3.6%) were discrepant between RNA ISH and p16. In univariate analysis, all 3 tests correlated with better overall survival (OS), disease-specific survival (DSS), and disease-free survival (DFS) (all P<0.001). In multivariate analysis, OS correlated significantly with RNA (hazard ratio=0.39, P=0.001), DNA (0.53, P=0.03), and p16 (0.30, P<0.001), but DSS and DFS correlated significantly only with p16 (DSS: 0.36, P=0.006; DFS: 0.42, P=0.016). RNA ISH is more sensitive than DNA ISH in detecting HPV in OSCC, and it correlates strongly with p16. Although both tests were comparable, p16 more strongly stratified patient outcomes. PMID:21836494
Ukpo, Odey C; Flanagan, John J; Ma, Xiao-Jun; Luo, Yuling; Thorstad, Wade L; Lewis, James S
2011-09-01
280
PubMed
Pre-B-cell leukemia homeobox (Pbx)-regulating protein-1 (Prep1) is a ubiquitous homeoprotein involved in early development, genomic stability, insulin sensitivity, and hematopoiesis. Previously we have shown that Prep1 is a haploinsufficient tumor suppressor that inhibits neoplastic transformation by competing with myeloid ecotropic integration site 1 for binding to the common heterodimeric partner Pbx1. Epithelial-mesenchymal transition (EMT) is controlled by complex networks of proinvasive transcription factors responsive to paracrine factors such as TGF-?. Here we show that, in addition to inhibiting primary tumor growth, PREP1 is a novel EMT inducer and prometastatic transcription factor. In human non-small cell lung cancer (NSCLC) cells, PREP1 overexpression is sufficient to trigger EMT, whereas PREP1 down-regulation inhibits the induction of EMT in response to TGF-?. PREP1 modulates the cellular sensitivity to TGF-? by inducing the small mothers against decapentaplegic homolog 3 (SMAD3) nuclear translocation through mechanisms dependent, at least in part, on PREP1-mediated transactivation of a regulatory element in the SMAD3 first intron. Along with the stabilization and accumulation of PBX1, PREP1 induces the expression of multiple activator protein 1 components including the proinvasive Fos-related antigen 1 (FRA-1) oncoprotein. Both FRA-1 and PBX1 are required for the mesenchymal changes triggered by PREP1 in lung tumor cells. Finally, we show that the PREP1-induced mesenchymal transformation correlates with significantly increased lung colonization by cells overexpressing PREP1. Accordingly, we have detected PREP1 accumulation in a large number of human brain metastases of various solid tumors, including NSCLC. These findings point to a novel role of the PREP1 homeoprotein in the control of the TGF-? pathway, EMT, and metastasis in NSCLC. PMID:25157139
Risolino, Maurizio; Mandia, Nadia; Iavarone, Francescopaolo; Dardaei, Leila; Longobardi, Elena; Fernandez, Serena; Talotta, Francesco; Bianchi, Fabrizio; Pisati, Federica; Spaggiari, Lorenzo; Harter, Patrick N; Mittelbronn, Michel; Schulte, Dorothea; Incoronato, Mariarosaria; Di Fiore, Pier Paolo; Blasi, Francesco; Verde, Pasquale
2014-09-01
281
PubMed Central
The RUNX1/ETO (RE) fusion protein, which originates from the t(8;21) chromosomal rearrangement, is one of the most frequent translocation products found in de novo acute myeloid leukemia (AML). In RE leukemias, activated forms of the c-KIT tyrosine kinase receptor are frequently found, thereby suggesting oncogenic cooperativity between these oncoproteins in the development and maintenance of t(8;21) malignancies. In this report, we show that activated c-KIT cooperates with a C-terminal truncated variant of RE, REtr, to expand human CD34+ hematopoietic progenitors ex vivo. CD34+ cells expressing both oncogenes resemble the AML-M2 myeloblastic cell phenotype, in contrast to REtr-expressing cells which largely undergo granulocytic differentiation. Oncogenic c-KIT amplifies REtr-depended clonogenic growth and protects cells from exhaustion. Activated c-KIT reverts REtr-induced DNA damage and apoptosis. In the presence of activated c-KIT, REtr-downregulated DNA-repair genes are re-expressed leading to an enhancement of DNA-repair efficiency via homologous recombination. Together, our results provide new mechanistic insight into REtr and c-KIT oncogenic cooperativity and suggest that augmented DNA repair accounts for the increased chemoresistance observed in t(8;21)-positive AML patients with activated c-KIT mutations. This cell-protective mechanism might represent a new therapeutic target, as REtr cells with activated c-KIT are highly sensitive to pharmacological inhibitors of DNA repair. PMID:24897507
Wichmann, C; Quagliano-Lo Coco, I; Yildiz, Ö; Chen-Wichmann, L; Weber, H; Syzonenko, T; Döring, C; Brendel, C; Ponnusamy, K; Kinner, A; Brandts, C; Henschler, R; Grez, M
2015-01-01
282
PubMed Central
Cisplatin is the most important and efficacious chemotherapeutic agent for the treatment of advanced gastric cancer. Cisplatin forms inter- and intrastrand crosslinked DNA adducts and its cytotoxicity is mediated by propagation of DNA damage recognition signals to downstream pathways involving ATR, p53, p73, and mitogen-activated protein kinases, ultimately resulting in apoptosis. Cisplatin resistance arises through a multifactorial mechanism involving reduced drug uptake, increased drug inactivation, increased DNA damage repair, and inhibition of transmission of DNA damage recognition signals to the apoptotic pathway. In addition, a new mechanism has recently been revealed, in which the oncoprotein c-Myc suppresses bridging integrator 1 (BIN1), thereby releasing poly(ADP-ribose)polymerase 1, which results in increased DNA repair activity and allows cancer cells to acquire cisplatin resistance. The present paper focuses on the molecular mechanisms of cisplatin-induced apoptosis and of cisplatin resistance, in particular on the involvement of BIN1 in the maintenance of cisplatin sensitivity. PMID:22778941
Tanida, Satoshi; Mizoshita, Tsutomu; Ozeki, Keiji; Tsukamoto, Hironobu; Kamiya, Takeshi; Kataoka, Hiromi; Sakamuro, Daitoku; Joh, Takashi
2012-01-01
283
PubMed Central
Person, Rachel J.; Tokar, Erik J.; Xu, Yuanyuan; Orihuela, Ruben; Olive Ngalame, Ntube N.; Waalkes, Michael P.
2013-01-01
284
PubMed
Person, Rachel J; Tokar, Erik J; Xu, Yuanyuan; Orihuela, Ruben; Ngalame, Ntube N Olive; Waalkes, Michael P
2013-12-01
285
PubMed
Blocking the oncoprotein murine double minute 2 (MDM2)-p53 protein-protein interaction has long been considered to offer a broad cancer therapeutic strategy, despite the potential risks of selecting tumors harboring p53 mutations that escape MDM2 control. In this study, we report a novel small-molecule inhibitor of the MDM2-p53 interaction, SAR405838 (MI-77301), that has been advanced into phase I clinical trials. SAR405838 binds to MDM2 with K(i) = 0.88 nmol/L and has high specificity over other proteins. A cocrystal structure of the SAR405838:MDM2 complex shows that, in addition to mimicking three key p53 amino acid residues, the inhibitor captures additional interactions not observed in the p53-MDM2 complex and induces refolding of the short, unstructured MDM2 N-terminal region to achieve its high affinity. SAR405838 effectively activates wild-type p53 in vitro and in xenograft tumor tissue of leukemia and solid tumors, leading to p53-dependent cell-cycle arrest and/or apoptosis. At well-tolerated dose schedules, SAR405838 achieves either durable tumor regression or complete tumor growth inhibition in mouse xenograft models of SJSA-1 osteosarcoma, RS4;11 acute leukemia, LNCaP prostate cancer, and HCT-116 colon cancer. Remarkably, a single oral dose of SAR405838 is sufficient to achieve complete tumor regression in the SJSA-1 model. Mechanistically, robust transcriptional upregulation of PUMA induced by SAR405838 results in strong apoptosis in tumor tissue, leading to complete tumor regression. Our findings provide a preclinical basis upon which to evaluate SAR405838 as a therapeutic agent in patients whose tumors retain wild-type p53. PMID:25145672
Wang, Shaomeng; Sun, Wei; Zhao, Yujun; McEachern, Donna; Meaux, Isabelle; Barrière, Cédric; Stuckey, Jeanne A; Meagher, Jennifer L; Bai, Longchuan; Liu, Liu; Hoffman-Luca, Cassandra Gianna; Lu, Jianfeng; Shangary, Sanjeev; Yu, Shanghai; Bernard, Denzil; Aguilar, Angelo; Dos-Santos, Odette; Besret, Laurent; Guerif, Stéphane; Pannier, Pascal; Gorge-Bernat, Dimitri; Debussche, Laurent
2014-10-15
286
PubMed Central
Background Human papillomaviruses (HPVs) are the primary etiological agents of cervical cancer and are also involved in the development of other tumours (skin, head and neck). Serological survey of the HPV infections is important to better elucidate their natural history and to disclose antigen determinants useful for vaccine development. At present, the analysis of the HPV-specific antibodies has not diagnostic value for the viral infections, and new approaches are needed to correlate the antibody response to the disease outcome. The aim of this study is to develop a novel ELISA, based on five denatured recombinant HPV16 proteins, to be used for detection HPV-specific antibodies. Methods The HPV16 L1, L2, E4, E6 and E7 genes were cloned in a prokaryotic expression vector and expressed as histidine-tagged proteins. These proteins, in a denatured form, were used in ELISA as coating antigens. Human sera were collected from women with abnormal PAP smear enrolled during an ongoing multicenter HPV-PathogenISS study in Italy, assessing the HPV-related pathogenetic mechanisms of progression of cervical cancer precursor lesions. Negative human sera were collected from patients affected by other infectious agents. All the HPV-positive sera were also subjected to an avidity test to assess the binding strength in the antigen-antibody complexes. Results Most of the sera showed a positive reactivity to the denatured HPV16 proteins: 82% of the sera from HPV16 infected women and 89% of the sera from women infected by other HPV genotypes recognised at least one of the HPV16 proteins. The percentages of samples showing reactivity to L1, L2 and E7 were similar, but only a few serum samples reacted to E6 and E4. Most sera bound the antigens with medium and high avidity index, suggesting specific antigen-antibody reactions. Conclusion This novel ELISA, based on multiple denatured HPV16 antigens, is able to detect antibodies in women infected by HPV16 and it is not genotype-specific, as it detects antibodies also in women infected by other genital HPVs. The assay is easy to perform and has low cost, making it suitable for monitoring the natural history of HPV infections as well as for detecting pre-existing HPV antibodies in women who receive VLP-based HPV vaccination. PMID:17150135
Di Bonito, Paola; Grasso, Felicia; Mochi, Stefania; Accardi, Luisa; Donà, Maria Gabriella; Branca, Margherita; Costa, Silvano; Mariani, Luciano; Agarossi, Alberto; Ciotti, Marco; Syrjänen, Kari; Giorgi, Colomba
2006-01-01
287
PubMed Central
The paper presents the development of a “proof-of-principle” hands-free and self-contained diagnostic platform for detection of human papillomavirus (HPV) E6/E7 mRNA in clinical specimens. The automated platform performs chip-based sample preconcentration, nucleic acid extraction, amplification, and real-time fluorescent detection with minimal user interfacing. It consists of two modular prototypes, one for sample preparation and one for amplification and detection; however, a common interface is available to facilitate later integration into one single module. Nucleic acid extracts (n = 28) from cervical cytology specimens extracted on the sample preparation chip were tested using the PreTect HPV-Proofer and achieved an overall detection rate for HPV across all dilutions of 50%–85.7%. A subset of 6 clinical samples extracted on the sample preparation chip module was chosen for complete validation on the NASBA chip module. For 4 of the samples, a 100% amplification for HPV 16 or 33 was obtained at the 1?:?10 dilution for microfluidic channels that filled correctly. The modules of a “sample-in, answer-out” diagnostic platform have been demonstrated from clinical sample input through sample preparation, amplification and final detection. PMID:22235204
Gulliksen, Anja; Keegan, Helen; Martin, Cara; O'Leary, John; Solli, Lars A.; Falang, Inger Marie; Grønn, Petter; Karlgård, Aina; Mielnik, Michal M.; Johansen, Ib-Rune; Tofteberg, Terje R.; Baier, Tobias; Gransee, Rainer; Drese, Klaus; Hansen-Hagge, Thomas; Riegger, Lutz; Koltay, Peter; Zengerle, Roland; Karlsen, Frank; Ausen, Dag; Furuberg, Liv
2012-01-01
288
PubMed Central
A mechanistic analysis of tumor immunity directed toward the viral oncoprotein simian virus 40 (SV40) large tumor antigen (Tag) has previously been described by our laboratory for scenarios of recombinant Tag immunization in BALB/c mice. In the present study, we performed a preliminary characterization of the immune components necessary for systemic tumor immunity induced upon immunization with plasmid DNA encoding SV40 Tag as a transgene (pCMV-Tag). Antibody responses to SV40 Tag were observed via indirect enzyme-linked immunosorbent assay following three intramuscular (i.m.) injections of pCMV-Tag and were typified by a mixed Th1/Th2 response. Complete tumor immunity within a murine model of pulmonary metastasis was achieved upon two i.m. injections of pCMV-Tag, as assessed by examination of tumor foci in mouse lungs, without a detectable antibody response to SV40 Tag. Induction-phase and effector-phase depletions of T cell subsets were performed in vivo via administration of depleting rat monoclonal antibodies, and these experiments demonstrated that CD4+ T lymphocytes are required in both phases of the adaptive immune response. Conversely, depletion of CD8+ T lymphocytes did not impair tumor immunity in either immune phase and resulted in the premature production of antibodies to SV40 Tag. Our findings are unique in that a dominant role could be ascribed to CD4+ T lymphocytes within a model of DNA vaccine-induced tumor immunity to Tag-expressing tumor cells. Additionally, our findings provide insight into the general mechanisms of vaccine-induced tumor immunity directed toward tumors bearing distinct tumor-associated antigens. PMID:21593176
Aldrich, Joel F.; Lowe, Devin B.; Shearer, Michael H.; Winn, Richard E.; Jumper, Cynthia A.; Bright, Robert K.; Kennedy, Ronald C.
2011-01-01
289
PubMed Central
Many plant species respond to herbivory with de novo production of a mixture of volatiles that attracts carnivorous enemies of the herbivores. One of the major components in the blend of volatiles produced by many different plant species in response to herbivory by insects and spider mites is the homoterpene 4,8-dimethyl-1,3(E),7-nonatriene. One study (J. Donath, W. Boland [1995] Phytochemistry 39: 785–790) demonstrated that a number of plant species can convert the acyclic sesquiterpene alcohol (3S)-(E)-nerolidol to this homoterpene. Cucumber (Cucumis sativus L.) and lima bean (Phaseolus lunatus L.) both produce 4,8-dimethyl-1,3(E),7-nonatriene in response to herbivory. We report the presence in cucumber and lima bean of a sesquiterpene synthase catalyzing the formation of (3S)-(E)-nerolidol from farnesyl diphosphate. The enzyme is inactive in uninfested cucumber leaves, slightly active in uninfested lima bean leaves, and strongly induced by feeding of the two-spotted spider mite (Tetranychus urticae Koch) on both plant species, but not by mechanical wounding. The activities of the (3S)-(E)-nerolidol synthase correlated well with the levels of release of 4,8-dimethyl-1,3(E),7-nonatriene from the leaves of the different treatments. Thus, (3S)-(E)-nerolidol synthase is a good candidate for a regulatory role in the release of the important signaling molecule 4,8-dimethyl-1,3(E),7-nonatriene. PMID:10482672
Bouwmeester, Harro J.; Verstappen, Francel W.A.; Posthumus, Maarten A.; Dicke, Marcel
1999-01-01
290
PubMed
In the present study, E6E7 and E6 proteins of human papillomaviruses (HPVs) associated with skin warts and cancer were compared for their transforming and carcinogenic abilities in primary human keratinocytes (PHKs). We show that E6E7 of cancer associated beta HPV types, notably 49 and 24, were able to extend the life span and enhance the clonogenic efficiency of PHKs when maintained in serum free/low calcium medium. Activities of the beta HPV E6E7 were lower than those of HPV16 E6E7. In contrast, E6 proteins from HPV types detected in skin warts or cancer, notably 10, 49 and 38, attenuated UVB induced protective responses in PHKs including cell death, proliferation arrest and accumulation of the proapoptotic proteins, p53, bax or bak. Together, this investigation revealed functional differences and commonalities between HPVs associated with skin warts and cancer, and allowed the identification of specific properties of beta HPVs supporting their involvement in skin carcinogenesis. PMID:25443667
Shterzer, Naama; Heyman, Dariya; Shapiro, Beny; Yaniv, Abraham; Jackman, Anna; Serour, Francis; Chaouat, Malka; Gonen, Pinhas; Tommasino, Massimo; Sherman, Levana
2014-11-01
291
PubMed Central
ABSTRACT Infections with high-risk human papillomaviruses (hrHPV) contribute to cervical carcinoma. The cdk inhibitor and tumor suppressor p16INK4A is consistently upregulated in cervical carcinoma cells for reasons that are poorly understood. We report here that downregulation of p16INK4A gene expression in three different cervical carcinoma cell lines reduced expression of the E7 oncogene, suggesting a positive feedback loop involving E7 and p16INK4A. p16INK4A depletion induced cellular senescence in HeLa but not CaSki and MS-751 cervical carcinoma cells. IMPORTANCE This study demonstrates that the cdk inhibitor p16INK4A, frequently used as surrogate marker for transforming infections by human papillomaviruses of the high-risk group, is required for high-level expression of the E7 oncoproteins of HPV-16, HPV-18, and HPV-45 in cervical carcinoma cells. It is also demonstrated that depletion of p16INK4A induces senescence in HeLa but not CaSki or MS-751 cervical carcinoma cells. PMID:24599991
Pauck, Alexander; Lener, Barbara; Hoell, Monika; Kaiser, Andreas; Kaufmann, Andreas M.; Zwerschke, Werner
2014-01-01
292
PubMed
The tumor suppressor p16(INK4A) inhibits formation of enzymatically active complexes of cyclin-dependent kinases 4 and 6 (CDK4/6) with D-type cyclins. Oncogenic stress induces p16(INK4A) expression, which in turn triggers cellular senescence through activation of the retinoblastoma tumor suppressor. Subversion of oncogene-induced senescence is a key step during cancer development, and many tumors have lost p16(INK4A) activity by mutation or epigenetic silencing. Human papillomavirus (HPV)-associated tumors express high levels of p16(INK4A) in response to E7 oncoprotein expression. Induction of p16(INK4A) expression is not a consequence of retinoblastoma tumor suppressor inactivation but is triggered by a cellular senescence response and is mediated by epigenetic derepression through the H3K27-specific demethylase (KDM)6B. HPV E7 expression causes an acute dependence on KDM6B expression for cell survival. The p16(INK4A) tumor suppressor is a critical KDM6B downstream transcriptional target and its expression is critical for cell survival. This oncogenic p16(INK4A) activity depends on inhibition of CDK4/CDK6, suggesting that in cervical cancer cells where retinoblastoma tumor suppressor is inactivated, CDK4/CDK6 activity needs to be inhibited in order for cells to survive. Finally, we note that HPV E7 expression creates a unique cellular vulnerability to small-molecule KDM6A/B inhibitors. PMID:24046371
McLaughlin-Drubin, Margaret E; Park, Donglim; Munger, Karl
2013-10-01
293
SciTech Connect
Person, Rachel J.; Tokar, Erik J.; Xu, Yuanyuan; Orihuela, Ruben; Ngalame, Ntube N. Olive; Waalkes, Michael P., E-mail: [email protected]
2013-12-01
294
Cbl has emerged as a novel signal transducing protein downstream of a number of cell surface receptors coupled to tyrosine kinases. Identified as the protein product of the c-cbl proto-oncogene, the cellular homolog to the transforming gene of a murine retrovirus, Cbl comprises an N-terminal transforming region (Cbl-N), which contains a phosphotyrosine binding (PTB) domain, and a C-terminal modular region
Mark L. Lupher Jr; Christopher E. Andoniou; David Bonita; Sachiko Miyake; Hamid Band
1998-01-01
295
PubMed
Since the identification of Nm23 (NME1, NME/NM23 nucleoside diphosphate kinase 1) as the first non-metastatic protein, a great deal of research on members of the NME family of proteins has focused on roles in processes implicated in carcinogenesis and particularly their regulation of cellular motility and the process of metastatic spread. To date, there are ten identified members of this family of genes, and these can be dichotomized into groups both taxonomically and by the presence or absence of their nucleoside diphosphate kinase activity with NMEs 1-4 encoding nucleoside diphosphate kinases (NDPKs) and NMEs 5-9 plus RP2 displaying little if any NDPK activity. NMEs are relatively small proteins that can form hetero-oligomers (typically hexamers), and given the apparent genetic redundancy of some NMEs and the number of different isoforms, it is perhaps not surprising that there remains a great deal of uncertainty regarding their function and even more regarding cellular mechanisms of action. Since residues that contribute to NDPK activity span much of the protein, it seems likely that the consequences of NME expression must be mediated through their NDPK activity, through interactions with other structures in cells including protein-protein interactions or through combinations of these. Our goal in this review is to focus on some of the protein-protein interactions that have been identified and to highlight some of the challenges that face this area of research. PMID:25366701
Vlatkovi?, Nikolina; Chang, Shie-Hong; Boyd, Mark T
2015-02-01
296
PubMed Central
While oncoproteins encoded by small DNA tumor viruses and Epstein-Barr virus (EBV) latent antigens facilitate G1/S progression, the EBV lytic switch transactivator Zta was found to inhibit growth by causing cell cycle arrest in G0/G1 in several epithelial tumor cell lines. Expression of Zta results in induction of the tumor suppressor protein, p53, and the cyclin-dependent kinase inhibitors, p21 and p27, as well as accumulation of hypophosphorylated pRb. Up-regulation of p53 and p27 occurs by post-transcriptional mechanisms while expression of p21 is induced at the RNA level in a p53-dependent manner. Inactivation of pRb by transient overexpression of the human papillomavirus E7 oncoprotein indicates that pRb or pRb-related proteins are key mediators of the growth-inhibitory function of Zta. These findings suggest that EBV plays an active role in redirecting epithelial cell physiology to facilitate the viral replicative program through a Zta-mediated growth arrest function. Images PMID:8654372
Cayrol, C; Flemington, E K
1996-01-01
297
PubMed Central
van de Putte, L B A; Rau, R; Breedveld, F; Kalden, J; Malaise, M; van Riel, P L C M; Schattenkirchner, M; Emery, P; Burmester, G; Zeidler, H; Moutsopoulos, H; Beck, K; Kupper, H
2003-01-01
298
PubMed Central
Background The mitotic Aurora-A kinase exerts crucial functions in maintaining mitotic fidelity. As a bona fide oncoprotein, Aurora-A aberrant overexpression leads to oncogenic transformation. Yet, the mechanisms by which Aurora-A enhances cancer cell survival remain to be elucidated. Results Here, we found that Aurora-A overexpression was closely correlated with clinic stage and lymph node metastasis in tongue carcinoma. Aurora-A inhibitory VX-680 suppressed proliferation, induced apoptosis and markedly reduced migration in cancer cells. We further showed that insulin-like growth factor-1, a PI3K physiological activator, reversed VX-680-decreased cell survival and motility. Conversely, wortmannin, a PI3K inhibitor, combined with VX-680 showed a synergistic effect on inducing apoptosis and suppressing migration. In addition, Aurora-A inhibition suppressed Akt activation, and VX-680-induced apoptosis was attenuated by Myr-Akt overexpression, revealing a cross-talk between Aurora-A and PI3K pathway interacting at Akt activation. Significantly, we showed that suppression of Aurora-A decreased phosphorylated Akt and was associated with increased IkappaB? expression. By contrast, Aurora-A overexpression upregulated Akt activity and downregulated IkappaB?, these changes were accompanied by nuclear translocation of nuclear factor-?B and increased expression of its target gene Bcl-xL. Lastly, Aurora-A overexpression induced IkappaB? reduction was abrogated by suppression of Akt either chemically or genetically. Conclusion Taken together, our data established that Aurora-A, via activating Akt, stimulated nuclear factor-?B signaling pathway to promote cancer cell survival, and promised a novel combined chemotherapy targeting both Aurora-A and PI3K in cancer treatment. PMID:19891769
2009-01-01
299
PubMed Central
Polycyclic aromatic hydrocarbons (PAHs) are the products of incomplete combustion of organic materials, which are present in cigarette smoke, deep-fried food, and in natural crude oil. Since PAH-metabolites form DNA adducts and cause oxidative DNA damage, we asked if these environmental carcinogens could affect transforming potential of the human Polyomavirus JC oncoprotein, T-antigen (JCV T-antigen). We extracted DMSO soluble PAHs from Deepwater Horizon oil spill in the Gulf of Mexico (oil-PAHs), and detected several carcinogenic PAHs. The oil-PAHs were tested in exponentially growing cultures of normal mouse fibroblasts (R508), and in R508 stably expressing JCV T-antigen (R508/T). The oil-PAHs were cytotoxic only at relatively high doses (1:50–1:100 dilution), and at 1:500 dilution the growth and cell survival rates were practically unaffected. This non-toxic dose triggered however, a significant accumulation of reactive oxygen species (ROS), caused oxidative DNA damage and the formation of DNA double strand breaks (DSBs). Although oil-PAHs induced similar levels of DNA damage in R508 and R508/T cells, only T-antigen expressing cells demonstrated inhibition of high fidelity DNA repair by homologous recombination (HRR). In contrast, low-fidelity repair by non-homologous end joining (NHEJ) was unaffected. This potential mutagenic shift between DNA repair mechanisms was accompanied by a significant increase in clonal growth of R508/T cells chronically exposed to low doses of the oil-PAHs. Our results indicate for the first time carcinogenic synergy in which oil-PAHs trigger oxidative DNA damage and JCV T-antigen compromises DNA repair fidelity. PMID:23558788
WILK, ANNA; RSKI, PIOTR WALIGÓ; LASSAK, ADAM; VASHISTHA, HIMANSHU; LIRETTE, DAVID; TATE, DAVID; ZEA, ARNOLD H.; KOOCHEKPOUR, SHAHRIAR; RODRIGUEZ, PAULO; MEGGS, LEONARD G.; ESTRADA, JOHN J.; OCHOA, AUGUSTO; REISS, KRZYSZTOF
2014-01-01
300
PubMed Central
The immunoglobulin enhancer-binding proteins, E12 and E47, encoded by the E2A gene belong to the basic helix-loop-helix (bHLH) family of regulatory proteins and act as transcriptional activators. In addition to their critical role in B-lymphocyte development, the E12 and E47 proteins have been implicated in the induction of myogenesis as heterodimeric partners of myogenic bHLH proteins, MyoD and myogenin. Here we demonstrate that the E2A proteins form heterodimers with the bHLH oncoprotein tal-1 in myeloid and erythroid cells and that these heterodimers specifically bind to the CANNTG DNA motif. Heterodimerization with tal-1 represses transactivation by E47 and could function to prevent the expression of immunoglobulin genes in cells other than B lymphocytes. DNA binding by E2A-tal-1 heterodimers in the M1 mouse myeloid cell line is abrogated upon terminal macrophage differentiation induced by the cytokine interleukin 6. The loss of E2A-tal-1 DNA binding is correlated with elevated expression of mRNA encoding the dominant negative HLH proteins, Id1 and particularly Id2. Moreover, recombinant Id proteins inhibit the E2A-tal-1-specific DNA binding activity from undifferentiated M1 cells. These results suggest that E2A-tal-1 heterodimers may play a role in preventing terminal differentiation in the myeloid lineage and provide a possible explanation for oncogenic transformation induced by ectopic tal-1 expression in acute T-cell lymphoblastic leukemias. Images PMID:8016095
Voronova, A F; Lee, F
1994-01-01
301
This book reports on dimensional analysis; ideal fluid models; vortex-induced vibration; galloping and flutter; instability of tube and cylinder arrays; vibrations induced by oscillating flow; vibration induced by turbulence and sound; damping of structures; sound induced by vortex shedding; vibrations of a pipe containing a fluid flow; indices. It covers the analysis of the vibrations of structures exposed to fluid
1990-01-01
302
PubMed
Overexpression of oncoprotein Aurora-A increases drug resistance and promotes lung metastasis of breast cancer cells. Curcumin is an active anticancer compound in turmeric and curry. Here we observed that Aurora-A protein and kinase activity were reduced in curcumin-treated human breast chemoresistant nonmetastatic MCF-7 and highly metastatic cancer MDA-MB-231 cells. Curcumin acts in a similar manner to Aurora-A small interfering RNA (siRNA), resulting in monopolar spindle formation, S and G2/M arrest, and cell division reduction. Ectopic Aurora-A extinguished the curcumin effects. The anticancer effects of curcumin were enhanced by Aurora-A siRNA and produced additivity and synergism effects in cell division and monopolar phenotype, respectively. Combination treatment with curcumin overrode the chemoresistance to four Food and Drug Administration (FDA)-approved anticancer drugs (ixabepilone, cisplatin, vinorelbine, or everolimus) in MDA-MB-231 cells, which was characterized by a decrease in cell viability and the occurrence of an additivity or synergy effect. Ectopic expression of Aurora-A attenuated curcumin-enhanced chemosensitivity to these four tested drugs. A similar benefit of curcumin was observed in MCF-7 cells treated with ixabepilone, the primary systemic therapy to patients with invasive breast cancer (stages IIA-IIIB) before surgery. Antagonism effect was observed when MCF-7 cells were treated with curcumin plus cisplatin, vinorelbine or everolimus. Curcumin-induced enhancement in chemosensitivity was paralleled by significant increases (additivity or synergy effect) in apoptosis and cell cycle arrest at S and G2/M phases, the consequences of Aurora-A inhibition. These results suggest that a combination of curcumin with FDA-approved anticancer drugs warrants further assessment with a view to developing a novel clinical treatment for breast cancer. PMID:24613085
Ke, Ching-Shiun; Liu, Hsiao-Sheng; Yen, Cheng-Hsin; Huang, Guan-Cheng; Cheng, Hung-Chi; Huang, Chi-Ying F; Su, Chun-Li
2014-05-01
303
PubMed Central
The M2 subtype Acute Myeloid Leukemia (AML-M2) with t(8;21) represents an unmet challenge because of poor clinical outcomes in a sizable portion of patients. In this study,we report that FTY720 (Fingolimod), a sphingosine analogue and an FDA approved drug for treating of multiple sclerosis, shows antitumorigenic activity against the Kasumi-1 cell line, xenograft mouse models and leukemic blasts isolated from AML-M2 patients with t(8;21) translocation. Primary investigation indicated that FTY720 caused cell apoptosis through caspases and protein phosphatase 2A (PP2A) activation. Transcriptomic profiling further revealed that FTY720 treatment could upregulate AML1 target genes and interfere with genes involved in ceramide synthesis. Treatment with FTY720 led to the elimination of AML1-ETO oncoprotein and caused cell cycle arrest. More importantly, FTY720 treatment resulted in rapid and significant increase of pro-apoptotic ceramide levels, determined by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry based lipidomic approaches. Structural simulation model had also indicated that the direct binding of ceramide to inhibitor 2 of PP2A (I2PP2A) could reactivate PP2A and cause cell death. This study demonstrates, for the first time, that accumulation of ceramide plays a central role in FTY720 induced cell death of AML-M2 with t(8;21). Targeting sphingolipid metabolism by using FTY720 may provide novel insight for the drug development of treatment for AML-M2 leukemia. PMID:25050888
Li, Lianchun; Liu, Yuan-Fang; Wang, Jiang; Liu, Hong; Song, Heng; Jiang, Hualiang; Chen, Sai-Juan; Luo, Cheng; Li, Keqin Kathy
2014-01-01
304
DNA-damaging agents signal to p53 through as yet unidentified posttranscriptional mechanisms. Here we show that phosphorylation of human p53 at serine 15 occurs after DNA damage and that this leads to reduced interaction of p53 with its negative regulator, the oncoprotein MDM2, in vivo and in vitro. Furthermore, using purified DNA-dependent protein kinase (DNA-PK), we demonstrate that phosphorylation of p53
Sheau-Yann Shieh; Masako Ikeda; Yoichi Taya; Carol Prives
1997-01-01
305
PubMed
Abnormalities in the homeostasis mechanisms involved in cell survival and apoptosis are contributing factors for colon carcinogenesis. Interventions of these mechanisms by pharmacologically safer agents gain predominance in colon cancer prevention. We previously reported the chemopreventive efficacy of hesperidin against colon carcinogenesis. In the present study, we aimed at investigating the potential of hesperidin over the abrogated Aurora-A coupled pro-survival phosphoinositide-3-kinase (PI3K)/Akt signalling cascades. Further, the role of hesperidin over apoptosis and mammalian target of rapamycin (mTOR) mediated autophagic responses were studied. Azoxymethane (AOM) induced mouse model of colon carcinogenesis was involved in this study. Hesperidin treatment was provided either in initiation/post-initiation mode respectively. Hesperidin significantly altered AOM mediated anti-apoptotic scenario by modulating Bax/Bcl-2 ratio together with enhanced cytochrome-c release and caspase-3, 9 activations. In addition, hesperidin enhanced p53-p21 axis with concomitant decrease in cell cycle regulator. Hesperidin treatment caused significant up-regulation of tumour suppressor phosphatase and tensin homologue (PTEN) with a reduction in the expression of AOM mediated p-PI3K and p-Akt. Additionally, hesperidin administration exhibited inhibition against p-mTOR expression which in turn led to stimulation of autophagic markers Beclin-1 and LC3-II. Aurora-A an upstream regulator of PI3K/Akt pathway was significantly inhibited by hesperidin. Furthermore, hesperidin administration restored glycogen synthase kinase-3 beta (GSK-3?) activity which in turn prevented the accumulation of oncoproteins ?-catenin, c-jun and c-myc. Taken together, hesperidin supplementation initiated apoptosis via targeted inhibition of constitutively activated Aurora-A mediated PI3K/Akt/GSK-3? and mTOR pathways coupled with autophagic stimulation against AOM induced colon carcinogenesis. PMID:25047426
Saiprasad, Gowrikumar; Chitra, Palanivel; Manikandan, Ramar; Sudhandiran, Ganapasam
2014-09-01
306
In the present work we focused our attention on studies of PVK:TNF hybrid polymer liquid crystal panels under short pulse laser illumination conditions. The diffraction gratings in a LC panel were induced by crossed beams generated by doubled in frequency Nd:YAG laser ((lambda) equals 532 nm) delivering pulses of 20 ps duration. So induced gratings were read by a cw laser radiation coming from a weak power He-Ne laser working at (lambda) equals 632.8 nm. The temporal evolution of intensity of first order diffraction measured in PVK:TNF hybrid liquid crystal panels shows many interesting features and complexity dependent on various experimental conditions. The substantial diffraction is observed already in time less than 1 ms after the pulse and the grating decay is completed within hundreds of milliseconds. At least three different steps of grating build-up can be distinguished which depend in various ways on the experimental conditions. A tentative mechanism of the observed responses is discussed in connection with the photoconductive properties of polymeric layers and the optical and electrical properties of the used liquid crystal E-7 (Merck).
Bartkiewicz, Stanislaw; Miniewicz, Andrzej; Sahraoui, Bouchta; Kajzar, Francois
2002-06-01
307
SciTech Connect
This book reports on dimensional analysis; ideal fluid models; vortex-induced vibration; galloping and flutter; instability of tube and cylinder arrays; vibrations induced by oscillating flow; vibration induced by turbulence and sound; damping of structures; sound induced by vortex shedding; vibrations of a pipe containing a fluid flow; indices. It covers the analysis of the vibrations of structures exposed to fluid flows; explores applications for offshore platforms and piping; wind-induced vibration of buildings, bridges, and towers; and acoustic and mechanical vibration of heat exchangers, power lines, and process ducting.
Blevins, R.D.
1990-01-01
308
DOEpatents
An improvement in an inducer for a pump wherein the inducer includes a hub, a plurality of radially extending substantially helical blades and a wall member extending about and encompassing an outer periphery of the blades. The improvement comprises forming adjacent pairs of blades and the hub to provide a substantially rectangular cross-sectional flow area which cross-sectional flow area decreases from the inlet end of the inducer to a discharge end of the inducer, resulting in increased inducer efficiency improved suction performance, reduced susceptibility to cavitation, reduced susceptibility to hub separation and reduced fabrication costs.
Dunn, Charlton (Calabasas, CA); Subbaraman, Maria R. (Canoga Park, CA)
1989-01-01
309
E-print Network
It has been shown that the old-fashioned idea of Sakharov's induced gravity and gauge interactions in the "one-loop dominance" version works astonishingly well yielding reasonable parameters. It appears that induced coupling constants of gauge interactions of the standard model assume qualitatively realistic values. Moreover, it is possible to induce the Barbero--Immirzi parameter of canonical gravity from the fields entering the standard model.
Bogus?aw Broda; Micha? Szanecki
2010-12-06
310
Movies provide the objects and subjects for the gaze of many people, and for some people, movies induce them to travel to the locations where they were filmed. The data gathered at 12 US locations supports earlier anecdotal accounts of movie-induced tourism. This paper extends from earlier studies by suggesting a variety of reasons for this type of gaze and
Roger Riley; Dwayne Baker; Carlton S. Van Doren
1998-01-01
311
In a nematic liquid crystal where the director field has a splay-bend deformation mediated by the boundary conditions there is a certain intrinsic polarization density distribution characteristic of the flexoelectric properties of the medium. By application of an electric field perpendicular to the director, a twist is induced which is a measure of the flexoelectric anisotropy [I. Dozov, Ph. Martinot-Lagarde, and G. Durand, J. Phys. (Paris) Lett. 43, L-365 (1982)]. We show that in molecules susceptible to a photoinduced configurational change we may change the volume polarization by UV illumination and relate the change in flexoelectric coefficients to the configurational change in the molecule. In the experiment we use the British Drug House (Merck) nematic mixture E7 doped with 5 wt % of the dye 4-hexyloxy-(4'-hexyl)azobenzene. The photoinduced trans-cis configurational change leads to an increase by 40% in the flexoelectric anisotropy (es-eb)/K.
Hermann, D. S.; Rudquist, P.; Ichimura, K.; Kudo, K.; Komitov, L.; Lagerwall, S. T.
1997-03-01
312
PubMed
Intense research after Hiroshima and Nagasaki atomic bomb (A-bomb) tragedy and Chernobyl nuclear plant accident revealed that ionizing radiation (IR) more than 100 mSv induces cancers that are indistinguishable from sporadic tumors. It remains controversial whether low dose IR (less than 100 mSv) is oncogenic or not. Among IR-induced malignancies, leukemia (A-bomb) and thyroid cancers (Chernobyl), in which chimeric(fusion) oncogenes formed by chromosome translocations play a critical role, develop with relatively short latency. All other cancers develop after long latency. Age-related epigenetic changes, as well as additional genetic alterations, would contribute to IR-induced carcinogenesis. PMID:22514919
Inaba, Toshiya
2012-03-01
313
PubMed Central
Awareness of the need for prevention of glucocorticoid- induced fractures is growing, but glucocorticoid administration is often overlooked as the most common cause of nontraumatic osteonecrosis. Glucocorticoid- induced osteonecrosis develops in 9–40% of patients receiving long-term therapy although it may also occur with short-term exposure to high doses, after intra-articular injection, and without glucocorticoid-induced osteoporosis. The name, osteonecrosis, is misleading because the primary histopathological lesion is osteocyte apoptosis. Apoptotic osteocytes persist because they are anatomically unavailable for phagocytosis and, with glucocorticoid excess, decreased bone remodeling retards their replacement. Glucocorticoid-induced osteocyte apoptosis, a cumulative and unrepairable defect, uniquely disrupts the mechanosensory function of the osteocyte–lacunar–canalicular system and thus starts the inexorable sequence of events leading to collapse of the femoral head. Current evidence indicates that bisphosphonates may rapidly reduce pain, increase ambulation, and delay joint collapse in patients with osteonecrosis. PMID:22169965
Weinstein, Robert S.
2013-01-01
314
MedlinePLUS
... this person's face have resulted from drug-induced vitiligo. Loss of melanin, the primary skin pigment, occasionally ... is the case with this individual. The typical vitiligo lesion is flat (macular) and depigmented, but maintains ...
315
PubMed
Statins are an effective treatment for the prevention of cardiovascular diseases and used extensively worldwide. However, myotoxicity induced by statins is a common adverse event and a major barrier to maximising cardiovascular risk reduction. The clinical spectrum of statin induced myotoxicity includes asymptomatic rise in creatine kinase concentration, myalgia, myositis and rhabdomyolysis. In certain cases, the cessation of statin therapy does not result in the resolution of muscular symptoms or the normalization of creatine kinase, raising the possibility of necrotizing autoimmune myopathy. There is increasing understanding and recognition of the pathophysiology and risk factors of statin induced myotoxicity. Careful history and physical examination in conjunction with selected investigations such as creatine kinase measurement, electromyography and muscle biopsy in appropriate clinical scenario help diagnose the condition. The management of statin induced myotoxicity involves statin cessation, the use of alternative lipid lowering agents or treatment regimes, and in the case of necrotizing autoimmune myopathy, immunosuppression. PMID:22560377
Sathasivam, Sivakumar
2012-06-01
316
MedlinePLUS
... the condition is called drug-induced immune thrombocytopenia. Heparin, a blood thinner, is the most common cause ... include: Immunoglobulin therapy (IVIG) given through a vein Plasma exchange (plasmapheresis) Platelet transfusions Corticosteroids
317
MedlinePLUS
... cleaning habits A build-up of the yeast Candida albicans , which can cause an infection Denture-induced ... They are more likely to be infected with Candida . People who smoke and those who do not ...
318
MedlinePLUS
Toxic hepatitis ... to get liver damage. Some drugs can cause hepatitis with small doses, even if the liver breakdown ... liver. Many different drugs can cause drug-induced hepatitis. Painkillers and fever reducers that contain acetaminophen are ...
319
Medications and herbal supplements can induce a variety of hepatic, acute, and chronic cholestatic syndromes including bland\\u000a cholestasis, cholestasis with concurrent hepatitis, bile duct injury, and extrahepatic biliary strictures and stones. Most\\u000a cases of drug- and herbal-induced cholestasis are benign, but progression to chronic liver disease, cirrhosis, and death is\\u000a well described. We discuss the different types of cholestasis that
James P. Hamilton; Jacqueline M. Laurin
320
\\u000a Chemotherapy-induced neurotoxicity is a common and dose-limiting side effect of many cancer treatments. While other dose-limiting\\u000a toxicities such as myelosupression and hypersensitivity reactions are largely amenable to treatment, chemotherapy-induced\\u000a neurotoxicity remains a significant problem, with limited treatment options and no standardized diagnostic or management criteria.\\u000a Receiving a full course of chemotherapy on schedule is a critical factor that determines patient
Susanna B. Park; Matthew C. Kiernan
321
PubMed Central
Isoniazid is a safe and very effective antituberculosis drug. Antimitotic agents routinely cause alopecia. Drug-induced alopecia is usually reversible upon withdrawal of the drug. Isoniazid, thiacetazone and ethionamide are the antituberculosis drugs which have been associated with alopecia. Isoniazid-induced alopecia was observed in one case and confirmed by the finding that hair growth resumed when drug removed from the regimen. PMID:21654989
Gupta, K. B.; Kumar, V.; Vishvkarma, S.; Shandily, R.
2011-01-01
322
PubMed Central
Drug-induced galactorrhea has been reported with agents such as antidopaminergic antiemetics, antipsychotics, etc., with few case reports of galactorrhea with selective serotonin reuptake inhibitors, including paroxetine, being reported in last few decades. Prolactin levels have been found to be either raised or normal in these cases. We here report a case of paroxetine induced galactorrhea in a 48-year-old female patient of obsessive compulsive disorder, having hyperprolactinemic and euprolactinemic galactorrhea at different time with a pituitary incidentaloma.
Gulati, Prannay; Chavan, B. S.; Das, Subhash
2014-01-01
323
PubMed Central
Electroconvulsive therapy can induce mania. A recent change in the Diagnostic and Statistical Manuel of Mental Disorders, Fifth Edition classifies electroconvulsive therapy-induced manic episodes as a bipolar type I diagnosis. There are no current established guidelines to treat such condition. The following clinical vignette describes a vignette in which a manic episode occurred following electroconvulsive therapy treatment. This case report examines the potential benefit of prescribing mood stabilizers during the acute episode and for maintenance care.
Lee, Jae; Arcand, Laura; Narang, Puneet
2014-01-01
324
PubMed Central
Background Human cervical cancer oncoprotein 1 (HCCR-1), reported as a negative regulator of p53, is over-expressed in a variety of human cancers. However, it is yet unknown whether HCCR-1 plays any role in pancreatic cancer development. The aim of this study was to investigate the effect of epidermal growth factor on the expression of HCCR in pancreatic cancer cells, and to explore if PI3K/Akt/mTOR signaling pathway mediated this expression. Methods A polyclonal antibody against HCCR protein was raised by immunizing Balb/c mice with the purified recombinant protein pMBPc-HCCR. Tissue samples were constructed on a tissue chip, and the expression of HCCR was investigated by immunohistochemistry assay and Western blotting. Pancreatic cell line, PANC-1 cells were stably transfected with plasmids containing sense-HCCR-1 fragment and HCCR siRNA fragment. MTT and transwell assay were used to investigate the proliferation and invasion of stable tansfectants. The specific inhibitor of PI3K and mTOR was used to see if PI3K/mTOR signal transduction was involved in the induction of HCCR gene expression. A Luciferase assay was used to see if Akt can enhance the HCCR promoter activity. Results HCCR was up-regulated in pancreatic tumor tissues (mean Allred score 4.51 ± 1.549 vs. 2.87 ± 2.193, P < 0.01), especially with high expression in poorly differentiated pancreatic cancer. The growth of cells decreased in HCCR-1 siRNA transfected cells compared with vector transfectants. The number of invasion cells was significantly lower in HCCR-1 siRNA transfected cells (24.4 ± 9.9) than that in vector transfectants (49.1 ± 15.4). Treatment of PANC-1 cells with epidermal growth factor increased HCCR protein level in a dose- and time-dependent manner. However, application of LY294002 and rapamycin caused a dramatic reduction of epidermal growth factor-induced HCCR expression. Over-expression of exogenous constitutively active Akt increased the HCCR promoter activity; in contrast, dominant negative Akt decreased the promoter activity. Conclusions EGF-induced HCCR-1 over-expression is mediated by PI3K/AKT/mTOR signaling which plays a pivotal role in pancreatic tumor progression, suggesting that HCCR-1 could be a potential target for cancer therapeutics. PMID:20423485
2010-01-01
325
SciTech Connect
A laboratory scale experiment was conducted to examine the use of induced polarization and electrical conductivity to monitor microbial induced sulfide precipitation under anaerobic conditions in sand filled columns. Three columns were fabricated; one for electrical measurements, one for geochemical sampling and a third non-inoculated column was used as a control. A continual upward flow of nutrients and metals in solution was established in each column. Desulfovibrio vulgaris microbes were injected into the middle of the geochemical and electrical columns. Iron and zinc sulfides precipitated along a microbial action front as a result of sulfate reduction due by Desulfovibrio vulgaris. The precipitation front initially developed near the microbial injection location, and subsequently migrated towards the nutrient inlet, as a result of chemotaxis by Desulfovibrio vulgaris. Sampling during and subsequent to the experiment revealed spatiotemporal changes in the biogeochemical measurements associated with microbial sulfate reduction. Conductivity measurements were insensitive to all biogeochemical changes occurred within the column. Changes in the IP response (of up to 14 mrad)were observed to coincide in place and in time with the active microbe respiration/sulfide precipitation front as determined from geochemical sampling. The IP response is correlated with the lactate concentration gradient, an indirect measurement of microbial metabolism, suggesting the potential of IP as a method for monitoring microbial respiration/activity. Post experimental destructive sample analysis and SEM imaging verified the geochemical results and supported our hypothesis that microbe induced sulfide precipitation is directly detectable using electrical methods. Although the processes not fully understood, the IP response appears to be sensitive to this anaerobic microbial precipitation, suggesting a possible novel application for the IP method.
Ntarlagiannis, Dimitrios; Williams, Kenneth Hurst; Slater, Lee; Hubbard, Susan
2004-06-04
326
PubMed
A substantial number of all panniculitides fails to recognize a specific etiology, and that is true also for a relatively frequent type of panniculitis, such as erythema nodosum (EN). Between the recognized causative factors of panniculitides, infectious, physical agents, autoimmune mechanisms and neoplastic disorders are well known. On the contrary, the role of drugs as inducers of panniculitides is marginally considered, and their report limited to anecdotal observations, often without due histopathological support. Since the clinical and histopathological features of drug-induced panniculitides are indistinguishable from those caused by other agents, the causative relationship may be demonstrated by the history of previous drug intake and by clinical improvement after drug discontinuation. We reviewed the currently reported descriptions of drug-induced panniculitis, including a few exemplificative original observations. EN results as the most frequently reported drug-induced panniculitis. Among the causative drugs of EN a variety of medications, with disparate, or even opposite, mechanisms of action are reported, thus limiting the understanding of the pathogenesis. Common causative drugs include oral contraceptives, nonsteroidal anti-inflammatory drugs, antiobiotics and leukotriene-modifying agents. Unfortunately, in several cases, the diagnosis of drug-induced EN is done on clinical findings alone. In those cases, the lack of histopathological support does not allow to define a precise clinicopathological correlation on etiologic grounds. Drug-induced lobular and mixed panniculitides, including eosinophilic panniculitis, are even more rarely described. Reported causative agents are glatiramer acetate, interferon beta and heparin (at sites of injections), and systemic steroids, tyrosine kinase inhibitors and BRAF with subcutaneous fat involvement at distance. In view of the recent introduction of new classes of drugs, attention should be paid to disclose their possible etiologic role in inducing among other side effects, also panniculitides. PMID:24819647
Borroni, G; Torti, S; D'Ospina, R M; Pezzini, C
2014-04-01
327
PubMed
Organophosphate pesticides (OPs) like malathion interfere with normal ovarian function resulting in an increased incidence of atresia and granulosa cell apoptosis that plays a consequential role in the loss of ovarian follicles or follicular atresia. The aim of present study was to assess malathion-induced (100 nM) reproductive stress, ultrastructural damage and changes in apoptosis frequency in ovarian granulosa cells of antral follicles. Transmission electron microscopy (TEM) was employed for ultrastructural characterization, oxidative stress was evaluated using thiobarbituric acid reactive substances (TBARS) assay to measure lipid peroxidation, and apoptosis was quantified via flow cytometry. By TEM, apoptosis was identified by the presence of an indented nuclear membrane with blebbing, pyknotic crescent-shaped fragmented nuclei, increased vacuolization, degenerating mitochondria, and lipid droplets. The results indicate a significant increase in malondialdehyde (MDA) level (nmols/g wet tissue) at a 100 nM dose of malathion i.e. 7.57±0.033*, 8.53±0.12*, and 12.87±0.78** at 4, 6, or 8 h, respectively, as compared with controls (6.07±0.033, p<0.01*, p<0.05**) showing a positive correlation between malathion-induced lipid peroxidation and percentage of granulosa cell apoptosis (r=1; p<0.01). The parallel use of these three methods enabled us to determine the role of malathion in inducing apoptosis as a consequence of cytogenetic damage and oxidative stress generated in granulosa cells of antral follicles. PMID:25409908
Bhardwaj, Jitender K; Saraf, Priyanka
2014-12-01
328
PubMed Central
Millions of people worldwide are currently infected with human papillomavirus (HPV), herpes simplex virus (HSV) or human immunodeficiency virus (HIV). For this enormous contingent of people, the search for preventive and therapeutic immunological approaches represents a hope for the eradication of latent infection and/or virus-associated cancer. To date, attempts to develop vaccines against these viruses have been mainly based on a monovalent concept, in which one or more antigens of a virus are incorporated into a vaccine formulation. In the present report, we designed and tested an immunization strategy based on DNA vaccines that simultaneously encode antigens for HIV, HSV and HPV. With this purpose in mind, we tested two bicistronic DNA vaccines (pIRES I and pIRES II) that encode the HPV-16 oncoprotein E7 and the HIV protein p24 both genetically fused to the HSV-1 gD envelope protein. Mice i.m. immunized with the DNA vaccines mounted antigen-specific CD8+ T cell responses, including in vivo cytotoxic responses, against the three antigens. Under experimental conditions, the vaccines conferred protective immunity against challenges with a vaccinia virus expressing the HIV-derived protein Gag, an HSV-1 virus strain and implantation of tumor cells expressing the HPV-16 oncoproteins. Altogether, our results show that the concept of a trivalent HIV, HSV, and HPV vaccine capable to induce CD8+ T cell-dependent responses is feasible and may aid in the development of preventive and/or therapeutic approaches for the control of diseases associated with these viruses. PMID:23951135
Santana, Vinicius C.; Diniz, Mariana O.; Cariri, Francisco A. M. O.; Ventura, Armando M.; Cunha-Neto, Edécio; Almeida, Rafael R.; Campos, Marco A.; Lima, Graciela K.; Ferreira, Luís C. S.
2013-01-01
329
PubMed
Millions of people worldwide are currently infected with human papillomavirus (HPV), herpes simplex virus (HSV) or human immunodeficiency virus (HIV). For this enormous contingent of people, the search for preventive and therapeutic immunological approaches represents a hope for the eradication of latent infection and/or virus-associated cancer. To date, attempts to develop vaccines against these viruses have been mainly based on a monovalent concept, in which one or more antigens of a virus are incorporated into a vaccine formulation. In the present report, we designed and tested an immunization strategy based on DNA vaccines that simultaneously encode antigens for HIV, HSV and HPV. With this purpose in mind, we tested two bicistronic DNA vaccines (pIRES I and pIRES II) that encode the HPV-16 oncoprotein E7 and the HIV protein p24 both genetically fused to the HSV-1 gD envelope protein. Mice i.m. immunized with the DNA vaccines mounted antigen-specific CD8? T cell responses, including in vivo cytotoxic responses, against the three antigens. Under experimental conditions, the vaccines conferred protective immunity against challenges with a vaccinia virus expressing the HIV-derived protein Gag, an HSV-1 virus strain and implantation of tumor cells expressing the HPV-16 oncoproteins. Altogether, our results show that the concept of a trivalent HIV, HSV, and HPV vaccine capable to induce CD8? T cell-dependent responses is feasible and may aid in the development of preventive and/or therapeutic approaches for the control of diseases associated with these viruses. PMID:23951135
Santana, Vinicius C; Diniz, Mariana O; Cariri, Francisco A M O; Ventura, Armando M; Cunha-Neto, Edécio; Almeida, Rafael R; Campos, Marco A; Lima, Graciela K; Ferreira, Luís C S
2013-01-01
330
PubMed
Abstract Carmustine is one of the alkylating chemotherapeutic agents, which are used to treat various types of cancers, such as brain tumors, Hodgkins and non-Hodgkins lymphoma and multiple myeloma. However, carmustine has the side effect of thrombocytopenia, and the mechanism is not completely understood. In this study, we show that carmustine dose-dependently induced depolarization of mitochondrial inner transmembrane potential (??m), up-regulation of Bax, down-regulation of Bcl-2 and caspase-3 activation. Carmustine did not induce surface expression of P-selectin or PAC-1 binding, whereas, obviously reduced collagen and thrombin-induced platelet aggregation. Dicumarol, c-Jun NH2-terminal kinase-specific inhibitor, reduced carmustine-induced ??m depolarization in platelets. The numbers of circulating platelets were reduced, and the tail bleeding time was significantly increased in mice that were injected with carmustine. Taken together, these data indicate that carmustine induced platelet apoptosis, suggesting the possible pathogenesis of thrombocytopenia in patients treated with carmustine. PMID:24955606
Zhang, Jie; Chen, Mengxing; Zhang, Yiwen; Zhao, Lili; Yan, Rong; Dai, Kesheng
2014-06-23
331
PubMed Central
The MYC oncoprotein is a transcription factor that coordinates cell growth and division. MYC overexpression exacerbates genomic instability and sensitizes cells to apoptotic stimuli. Here we demonstrate that MYC directly stimulates transcription of the human Werner syndrome gene, WRN, which encodes a conserved RecQ helicase. Loss-of-function mutations in WRN lead to genomic instability, an elevated cancer risk, and premature cellular senescence. The overexpression of MYC in WRN syndrome fibroblasts or after WRN depletion from control fibroblasts led to rapid cellular senescence that could not be suppressed by hTERT expression. We propose that WRN up-regulation by MYC may promote MYC-driven tumorigenesis by preventing cellular senescence. PMID:12842909
Grandori, Carla; Wu, Kou-Juey; Fernandez, Paula; Ngouenet, Celine; Grim, Jonathan; Clurman, Bruce E.; Moser, Michael J.; Oshima, Junko; Russell, David W.; Swisshelm, Karen; Frank, Scott; Amati, Bruno; Dalla-Favera, Riccardo; Monnat, Raymond J.
2003-01-01
332
PubMed Central
Radiation-induced gliomas represent a relatively rare but well-characterized entity in the neuro-oncologic literature. Extensive retrospective cohort data in pediatric populations after therapeutic intracranial radiation show a clearly increased risk in glioma incidence that is both patient age- and radiation dose/volume-dependent. Data in adults are more limited but show heightened risk in certain groups exposed to radiation. In both populations, there is no evidence linking increased risk associated with routine exposure to diagnostic radiation. At the molecular level, recent studies have found distinct genetic differences between radiation-induced gliomas and their spontaneously-occurring counterparts. Clinically, there is understandable reluctance on the part of clinicians to re-treat patients due to concern for cumulative neurotoxicity. However, available data suggest that aggressive intervention can lead to improved outcomes in patients with radiation-induced gliomas. PMID:19831840
2013-01-01
333
PubMed
Boljesíkova, E; Chorvath, M
2001-01-01
334
E-print Network
Neutron--induced nucleosynthesis plays an important role in astrophysical scenarios like in primordial nucleosynthesis in the early universe, in the s--process occurring in Red Giants, and in the $\\alpha$--rich freeze--out and r--process taking place in supernovae of type II. A review of the three important aspects of neutron--induced nucleosynthesis is given: astrophysical background, experimental methods and theoretical models for determining reaction cross sections and reaction rates at thermonuclear energies. Three specific examples of neutron capture at thermal and thermonuclear energies are discussed in some detail.
H. Oberhummer; H. Herndl; T. Rauscher; H. Beer
1996-08-20
335
The cytotoxic agent bleomycin is feared for its induction of sometimes\\u000a fatal pulmonary toxicity, also known as bleomycin-induced pneumonitis\\u000a (BIP). The central event in the development of BIP is endothelial damage\\u000a of the lung vasculature due to bleomycin-induced cytokines and free\\u000a radicals. Ultimately, BIP can progress in lung fibrosis. The diagnosis is\\u000a established by a combination of clinical symptoms, radiographic
S. Sleijfer
2001-01-01
336
PubMed
Erythroderma is a potentially serious and life-threatening skin disease with a number of possible aetiologies. Drug reactions are well-documented causes, with carbamazepine, penicillin and allopurinol being the most commonly implicated. This case describes a unique presentation of warfarin-induced erythroderma in a 78-year-old female patient. PMID:24592901
Rowe, Casey J; Robertson, Ivan; James, Daniel; McMeniman, Erin
2015-02-01
337
PubMed
A number of medications have been associated with uveitis. This review highlights both well-established and recently reported systemic, topical, intraocular, and vaccine-associated causes of drug-induced uveitis, and assigns a quantitative score to each medication based upon criteria originally described by Naranjo and associates. PMID:23522744
London, Nikolas Js; Garg, Sunir J; Moorthy, Ramana S; Cunningham, Emmett T
2013-01-01
338
DOEpatents
An improvement in a pump including a shrouded inducer, the improvement comprising first and second sealing means 32,36 which cooperate with a first vortex cell 38 and a series of secondary vortex cells 40 to remove any tangential velocity components from the recirculation flow.
Meng, Sen Y. (Reseda, CA)
1989-01-01
339
A project has been initiated to determine the feasibility of developing a complete airborne remote sensing system for rapidly mapping high concentration patches of bioluminescent organisms in the world's oceans. Conceptually, this system would be composed of a laser illuminator to induce bioluminescence and a low light level image intensifier for detection of light. Initial laboratory measurements consisted of using
G. D. Hickman; R. V. Lynch III
1981-01-01
340
DOEpatents
An improvement in a pump is described including a shrouded inducer, the improvement comprising first and second sealing means which cooperate with a first vortex cell and a series of secondary vortex cells to remove any tangential velocity components from the recirculation flow. 3 figs.
Meng, S.Y.
1989-08-08
341
PubMed Central
A number of medications have been associated with uveitis. This review highlights both well-established and recently reported systemic, topical, intraocular, and vaccine-associated causes of drug-induced uveitis, and assigns a quantitative score to each medication based upon criteria originally described by Naranjo and associates. PMID:23522744
2013-01-01
342
ERIC Educational Resources Information Center
The relationship of astigmatism to reading and the possible detrimental effects it might have on reading were investigated. The greatest incidence of astigmatism was for the with-the-rule type ranging from .50 to 1.00 diopter. This type of astigmatism was induced in 35 seniors from the Los Angeles College of Optometry by placing cylindrical lenses…
Schubert, Delwyn G.; Walton, Howard N.
1968-01-01
343
PubMed Central
Gynecomastia is very rare during antituberculosis chemotherapy. We describe a 38-year-old male patient who developed a painful gynecomastia following second-line drug therapy for multidrug-resistant pulmonary tuberculosis. Gynecomastia disappeared after stopping the ethionamide. A published literature on antituberculosis-induced gynecomastia is also briefly discussed. PMID:22629101
Dixit, Ramakant; George, Jacob; Sharma, Arun K.; chhabra, Naveen; Jangir, Suresh K.; Mishra, Vikas
2012-01-01
344
ERIC Educational Resources Information Center
Introductory physics laboratories have seen an influx of "conceptual integrated science" over time in their classrooms with elements of other sciences such as chemistry, biology, Earth science, and astronomy. We describe a laboratory to introduce this development, as it attracts attention to the voltage induced in the human brain as it is…
Abdul-Razzaq, W.; Biller, R. D.
2010-01-01
345
PubMed
Hyperkalemia is a common clinical condition that can be defined as a serum potassium concentration exceeding 5.0 mmol/L. Drug-induced hyperkalemia is the most important cause of increased potassium levels in everyday clinical practice. Drug-induced hyperkalemia may be asymptomatic. However, it may be dramatic and life threatening, posing diagnostic and management problems. A wide range of drugs can cause hyperkalemia by a variety of mechanisms. Drugs can interfere with potassium homoeostasis either by promoting transcellular potassium shift or by impairing renal potassium excretion. Drugs may also increase potassium supply. The reduction in renal potassium excretion due to inhibition of the renin-angiotensin-aldosterone system represents the most important mechanism by which drugs are known to cause hyperkalemia. Medications that alter transmembrane potassium movement include amino acids, beta-blockers, calcium channel blockers, suxamethonium, and mannitol. Drugs that impair renal potassium excretion are mainly represented by angiotensin-converting enzyme inhibitors, angiotensin-II receptor blockers, direct renin inhibitors, nonsteroidal anti-inflammatory drugs, calcineurin inhibitors, heparin and derivatives, aldosterone antagonists, potassium-sparing diuretics, trimethoprim, and pentamidine. Potassium-containing agents represent another group of medications causing hyperkalemia. Increased awareness of drugs that can induce hyperkalemia, and monitoring and prevention are key elements for reducing the number of hospital admissions, morbidity, and mortality related to drug-induced hyperkalemia. PMID:25047526
Ben Salem, Chaker; Badreddine, Atef; Fathallah, Neila; Slim, Raoudha; Hmouda, Houssem
2014-09-01
346
PubMed
Earthquakes in unusual locations have become an important topic of discussion in both North America and Europe, owing to the concern that industrial activity could cause damaging earthquakes. It has long been understood that earthquakes can be induced by impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into underground formations. Injection-induced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from previously unproductive formations. Earthquakes can be induced as part of the process to stimulate the production from tight shale formations, or by disposal of wastewater associated with stimulation and production. Here, I review recent seismic activity that may be associated with industrial activity, with a focus on the disposal of wastewater by injection in deep wells; assess the scientific understanding of induced earthquakes; and discuss the key scientific challenges to be met for assessing this hazard. PMID:23846903
Ellsworth, William L
2013-07-12
347
PubMed
Gynecomastia is very rare during antituberculosis chemotherapy. We describe a 38-year-old male patient who developed a painful gynecomastia following second-line drug therapy for multidrug-resistant pulmonary tuberculosis. Gynecomastia disappeared after stopping the ethionamide. A published literature on antituberculosis-induced gynecomastia is also briefly discussed. PMID:22629101
Dixit, Ramakant; George, Jacob; Sharma, Arun K; Chhabra, Naveen; Jangir, Suresh K; Mishra, Vikas
2012-04-01
348
An 81 year old man was admitted to hospital with pulmonary Mycobacterium tuberculosis infection and was treated with rifampicin (RFP), isoniazid (INH), and ethambutol (EB). On day 9 he developed fever and dyspnoea. Chest radiographs showed new infiltration shadows in the right lung. Bronchoalveolar lavage (BAL) was performed and increased numbers of lymphocytes were recovered. Drug induced pneumonitis was suspected
N Kunichika; N Miyahara; K Kotani; H Takeyama; M Harada; M Tanimoto
2002-01-01
349
AMALDI, d'Agostino and Segrè1 report that, using neutrons from a radon - alpha particle - beryllium source, they have induced an activity in indium of a very short half-life period (13 see.) and also one of half-life period of about one hour (54 min.).
Leo Szilard; T. A. Chalmers
1935-01-01
350
PubMed Central
In the treatment of tuberculosis there are special therapeutic problems related to adverse effects of drugs, compliance to treatment, and microbial resistance. Thrombocytopenia is an uncommon but potentially fatal adverse effect of certain anti-tubercular drugs when the incriminating drug is taken by a susceptible individual. We report a case of rifampicin-induced thrombocytopenia, which although rare, needs attention. PMID:20927251
Verma, Ajay Kumar; Singh, Arpita; Chandra, Amol; Kumar, Santosh; Gupta, Rajesh Kumar
2010-01-01
351
MedlinePLUS
Drug-induced pulmonary disease is lung disease brought on by a bad reaction to a medicine. ... Maldonado F, Limper AH. Drug-induced pulmonary disease. In: Mason RJ, ... of Respiratory Medicine . 5th ed. Philadelphia, PA: Elsevier ...
352
MedlinePLUS
Home Health Info Hearing, Ear Infections, and Deafness Noise-Induced Hearing Loss Noise-Induced Hearing Loss On this page: What is noise-induced hearing ... continue constantly or occasionally throughout a person’s life. Hearing loss ... or both ears. Sometimes exposure to impulse or continuous loud noise ...
353
Predator induced morphological defenses are marked morphological shifts induced directly by cues associated with a predator. Generally, remote cues, i.e., chemical substances emitted from predators or injured conspecifics, are considered to be ideal signals to induce morphological change in aquatic environments rather than close cues, i.e., close chemical or tactile cues, since chemical substances that can propagate over relatively long
Osamu Kishida; Kinya Nishimura
2004-01-01
354
PubMed Central
Tulipalin A induced phytotoxicity is a persistent allergic contact dermatitides documented in floral workers exposed to Alstroemeria and its cultivars.[1] The causative allergen is tulipalin A, a toxic glycoside named for the tulip bulbs from which it was first isolated.[2] The condition is characterized by fissured acropulpitis, often accompanied by hyperpigmentation, onychorrhexis, and paronychia. More of the volar surface may be affected in sensitized florists. Dermatitis and paronychia are extremely common conditions and diagnostic errors may occur. A thorough patient history, in conjunction with confirmatory patch testing with a bulb sliver and tuliposide A exposure, can prevent misdiagnosis. We report a case of Tulipalin A induced phytotoxicity misdiagnosed as an unresolved tinea manuum infection in a patient evaluated for occupational exposure. PMID:25024947
McCluskey, James; Bourgeois, Marie; Harbison, Raymond
2014-01-01
355
PubMed
Tulipalin A induced phytotoxicity is a persistent allergic contact dermatitides documented in floral workers exposed to Alstroemeria and its cultivars.[1] The causative allergen is tulipalin A, a toxic glycoside named for the tulip bulbs from which it was first isolated.[2] The condition is characterized by fissured acropulpitis, often accompanied by hyperpigmentation, onychorrhexis, and paronychia. More of the volar surface may be affected in sensitized florists. Dermatitis and paronychia are extremely common conditions and diagnostic errors may occur. A thorough patient history, in conjunction with confirmatory patch testing with a bulb sliver and tuliposide A exposure, can prevent misdiagnosis. We report a case of Tulipalin A induced phytotoxicity misdiagnosed as an unresolved tinea manuum infection in a patient evaluated for occupational exposure. PMID:25024947
McCluskey, James; Bourgeois, Marie; Harbison, Raymond
2014-04-01
356
PubMed Central
In a recent survey the incidence of pseudoelephantiasis induced by donovanosis was found to be 5%. The ratio of women to men was 3:1. The incubation period was two to 20 days, and the duration was two to 24 months. The disease was contracted through premarital or extramarital sexual intercourse. The morphological features were characterised in women by globular pedunculated verrucous surfaced swellings affecting the labia majora and the clitoris and accompanying ulceration or its aftermath (depigmentation), or both. Constitutional symptoms were absent. Intracytoplasmic Donovan bodies in the tissue or a smear from the ulcers were diagnostic. Immune markers, such as total T lymphocytes and their subsets (T4 (helper/inducer) and T8 (suppressor/cytotoxic), B lymphocytes, immunoglobulins G, A, and M, and the pivotal complement component C3 were largely inconsequential. Images PMID:3817826
Sehgal, V N; Jain, M K; Sharma, V K
1987-01-01
357
SciTech Connect
We propose and analyze a remote atmospheric lasing configuration which utilizes a combination of an ultrashort pulse laser to form a plasma filament (seed electrons) by tunneling ionization and a heater pulse which thermalizes the seed electrons. Electrons collisionally excite nitrogen molecules and induce lasing in the ultraviolet. The lasing gain is sufficiently high to reach saturation within the length of the plasma filament. A remotely generated ultraviolet source may have applications for standoff detection of biological and chemical agents.
Sprangle, Phillip; Penano, Joseph; Gordon, Daniel [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Hafizi, Bahman [Icarus Research, Inc., PO Box 30780, Bethesda, Maryland 20824-0780 (United States); Scully, Marlan [Departments of Physics and Electrical Engineering, Texas A and M University, College Station, Texas 77843 (United States); Departments of Chemistry and Aerospace and Mechanical Engineering, Princeton University, Princeton, New Jersey 08544 (United States)
2011-05-23
358
PubMed Central
This case describes a scenario of lime-induced phytophotodermatitis. Phytophotodermatitis is a dermatitis caused after the skin is exposed to photosensitizing compounds in plants and then exposed to sunlight. Many common plants including citrus fruits, celery, and wild parsnip contain these photosensitizing compounds which cause phytophotodermatitis. It is important for a physician to be aware of phytophotodermatitis because it may often be misdiagnosed as other skin conditions including fungal infection, cellulitis, allergic contact dermatitis, and even child abuse. PMID:25317269
Hankinson, Andrew; Lloyd, Benjamin; Alweis, Richard
2014-01-01
359
PubMed
This case describes a scenario of lime-induced phytophotodermatitis. Phytophotodermatitis is a dermatitis caused after the skin is exposed to photosensitizing compounds in plants and then exposed to sunlight. Many common plants including citrus fruits, celery, and wild parsnip contain these photosensitizing compounds which cause phytophotodermatitis. It is important for a physician to be aware of phytophotodermatitis because it may often be misdiagnosed as other skin conditions including fungal infection, cellulitis, allergic contact dermatitis, and even child abuse. PMID:25317269
Hankinson, Andrew; Lloyd, Benjamin; Alweis, Richard
2014-01-01
360
\\u000a Induced pluripotent stem (iPS) cells are embryonic stem-like cells produced by forcing expression of a minimal number of key\\u000a factors in differentiated somatic cells. In many ways, they are indistinguishable from embryonic stem cells in that they can\\u000a differentiate into any cell type in the body. This development has led to worldwide excitement over the possibility to develop\\u000a cell-based therapies
Raymond L. Page; Christopher Malcuit; Tanja Dominko
361
Cooperation between the adenovirus E1A and E1B oncogenes is required for transformation of primary quiescent rodent cells. Although expression of E1A alone will stimulate cell proliferation sufficient to initiate transformed focus formation, proliferation fails to be sustained and foci degenerate. Coexpression of either the 19-kDa or 55-kDa E1B oncoproteins with E1A permits high-frequency transformation by overcoming this cytotoxic response. Without
Lakshmi Rao; Michael Debbas; Peter Sabbatini; David Hockenbery; Stanley Korsmeyer; Eileen White
1992-01-01
362
NASA Technical Reports Server (NTRS)
Maintenance of euhydration is essential for maximum work performance. Environments which induce hypohydration reduce plasma volume and cardiovascular performance progressively declines as does work capacity. Hyperhydration prior to exposure to dehydrating environments appears to be a potential countermeasure to the debilitating effects of hypohydration. The extravascular fluid space, being the largest fluid compartment in the body, is the most logical space by which significant hyperhydration can be accomplished. Volume and osmotic receptors in the vascular space result in physiological responses which counteract hyperhydration. Our hypothesis is that glycerol-induced hyperhydration (GIH) can accomplish extravascular fluid expansion because of the high solubility of glycerol in lipid and aqueous media. A hypertonic solution of glycerol is rapidly absorbed from the gastrointestinal tract, results in mild increases in plasma osmolality and is distributed to 65 percent of the body mass. A large volume of water ingested within minutes after glycerol intake results in increased total body water because of the osmotic action and distribution of glycerol. The resulting expanded extravascular fluid space can act as a reservoir to maintain plasma volume during exposure to dehydrating environments. The fluid shifts associated with exposure to microgravity result in increased urine production and is another example of an environment which induces hypohydration. Our goal is to demonstrate that GIH will facilitate maintenance of euhydration and cardiovascular performance during space flight and upon return to a 1 g environment.
Riedesel, Marvin L.; Lyons, Timothy P.; Mcnamara, M. Colleen
1991-01-01
363
PubMed Central
Sepsis is a major cause of morbidity and mortality in critically ill patients, and despite advances in management, mortality remains high. In survivors, sepsis increases the risk for the development of persistent acquired weakness syndromes affecting both the respiratory muscles and the limb muscles. This acquired weakness results in prolonged duration of mechanical ventilation, difficulty weaning, functional impairment, exercise limitation, and poor health-related quality of life. Abundant evidence indicates that sepsis induces a myopathy characterized by reductions in muscle force-generating capacity, atrophy (loss of muscle mass), and altered bioenergetics. Sepsis elicits derangements at multiple subcellular sites involved in excitation contraction coupling, such as decreasing membrane excitability, injuring sarcolemmal membranes, altering calcium homeostasis due to effects on the sarcoplasmic reticulum, and disrupting contractile protein interactions. Muscle wasting occurs later and results from increased proteolytic degradation as well as decreased protein synthesis. In addition, sepsis produces marked abnormalities in muscle mitochondrial functional capacity and when severe, these alterations correlate with increased death. The mechanisms leading to sepsis-induced changes in skeletal muscle are linked to excessive localized elaboration of proinflammatory cytokines, marked increases in free-radical generation, and activation of proteolytic pathways that are upstream of the proteasome including caspase and calpain. Emerging data suggest that targeted inhibition of these pathways may alter the evolution and progression of sepsis-induced myopathy and potentially reduce the occurrence of sepsis-mediated acquired weakness syndromes. PMID:20046121
Callahan, Leigh Ann; Supinski, Gerald S.
2014-01-01
364
SciTech Connect
Morgan, William F.
2011-03-01
365
PubMed
We study a critically coupled system [Opt. Lett. 32, 1483 (2007)] with a Kerr nonlinear spacer layer. Nonlinearity is shown to inhibit null scattering in a critically coupled system at low powers. However, a system detuned from critical coupling can exhibit near-complete suppression of scattering by means of nonlinearity-induced changes in refractive index. Our studies reveal clearly an important aspect of critical coupling as a delicate balance in both the amplitude and the phase relations, while a nonlinear resonance in dispersive bistability concerns only the phase. PMID:23939099
Nireekshan Reddy, K; Gopal, Achanta Venu; Dutta Gupta, S
2013-07-15
366
E-print Network
We study a critically coupled system (Opt. Lett., \\textbf{32}, 1483 (2007)) with a Kerr-nonlinear spacer layer. Nonlinearity is shown to inhibit null-scattering in a critically coupled system at low powers. However, a system detuned from critical coupling can exhibit near-complete suppression of scattering by means of nonlinearity-induced changes in refractive index. Our studies reveal clearly an important aspect of critical coupling as a delicate balance in both the amplitude and the phase relations, while a nonlinear resonance in dispersive bistability concerns only the phase.
Reddy, K Nireekshan; Gupta, S Dutta
2013-01-01
367
E-print Network
Coherence-induced entanglement Fu-li Li, Han Xiong, and M. Suhail Zubairy Institute for Quantum Studies and Department of Physics, Texas A&M University, College Station, Texas 77843-4242, USA #1;Received 7 March 2005; published 19 July 2005#2... of atomic coherence. DOI: 10.1103/PhysRevA.72.010303 PACS number#1;s#2;: 03.67.Mn, 03.65.Ud Atomic coherence #3;1#4;, which results from a coherent su- perposition of different states of a single atom, can lead to many different quantum optical phenomena...
Li, F. L.; Xiong, H.; Zubairy, M. Suhail
2005-01-01
368
SciTech Connect
In the present paper we give a new methodology named, 'neutron induced beta radiography-NIBR' which makes use of neutron activated Dy or In foils as source of (3-radiation. Radiographs are obtained with an aluminium cassette containing image plate, a sample under inspection and the activated Dy or In foil kept in tight contact. The sensitivity of the technique to thickness was evaluated for different materials in the form of step wedges. Some radiographs are presented to demonstrate potential of method to inspect thin samples.
Shaikh, A. M.; Shylaja, D. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)
2011-07-15
369
DOEpatents
Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.
Becker, Lance B. (Chicago, IL); Hoek, Terry Vanden (Chicago, IL); Kasza, Kenneth E. (Palos Park, IL)
2008-09-09
370
DOEpatents
Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.
Becker, Lance B. (Chicago, IL); Hoek, Terry Vanden (Chicago, IL); Kasza, Kenneth E. (Palos Park, IL)
2003-04-15
371
PubMed Central
Cephalexin is a very commonly prescribed orally administered antibiotic which has many potential side effects. Amongst these cholestatic jaundice has been infrequently reported as an adverse reaction. We present a case of a 57-year-old male who exhibited features of cholestatic jaundice including elevated liver function tests (LFTs) after taking cephalexin and showed improvement on removal of the offending agent. During this time he was symptomatically treated with cholestyramine. Complete resolution of LFTs was seen in four weeks. Cephalexin induced cholestasis is rare and hence requires a high degree of clinical suspicion for prompt diagnosis and treatment. PMID:25180107
Jasdanwala, Sarfaraz; Mathur, Ajay; Eng, Margaret
2014-01-01
372
PubMed
Eosinophilic lung diseases (ELD) are a variety of several clinical entities, which may result from different etiologies, including drug treatment. Dapsone, a sulfone antibiotic widely used in leprosy (among other indications), has been described as a possible cause of ELD. We report a patient with leprosy who presented with respiratory symptoms and pulmonary infiltrates and was diagnosed as suffering from eosinophilic pneumonia. To the best of our knowledge, this is the first report in which the diagnosis of dapsone-induced eosinophilic pneumonia was supported by bronchoalveolar lavage, lung biopsy and typical response to therapy. PMID:22905598
Adar, T; Tayer-Shifman, O; Mizrahi, M; Tavdi, S; Barak, O; Shalit, M
2012-06-01
373
PubMed
We present conclusive evidence showing that different sources of diversity, such as those represented by quenched disorder or noise, can induce a resonant collective behavior in an ensemble of coupled bistable or excitable systems. Our analytical and numerical results show that when such systems are subjected to an external subthreshold signal, their response is optimized for an intermediate value of the diversity. These findings show that intrinsic diversity might have a constructive role and suggest that natural systems might profit from their diversity in order to optimize the response to an external stimulus. PMID:17155633
Tessone, Claudio J; Mirasso, Claudio R; Toral, Raúl; Gunton, James D
2006-11-10
374
PubMed
Exercise-induced asthma is characterized by a transient rise of the airways resistances, associated with asthmatic symptoms, 5 to 10 minutes after the end of a submaximal effort. The treatment is based on a pre-effort warming, cover the mouth with a mask (when the weather is cold), the use of beta-mimetic bronchodilators before exercise and, chronic treatment with antiinflammatory drugs. When the patient is not controlled, an evaluation of the lung function is required with a postbronchodilator control or an exercise challenge test. If the patient remains uncontrolled despite the treatment, others diagnostics should be excluded, such as vocal cords dysfunction or left heart failure. PMID:21089401
Michel, O
2010-09-01
375
PubMed Central
Drug-induced parkinsonism (DIP) is the second-most-common etiology of parkinsonism in the elderly after Parkinson's disease (PD). Many patients with DIP may be misdiagnosed with PD because the clinical features of these two conditions are indistinguishable. Moreover, neurological deficits in patients with DIP may be severe enough to affect daily activities and may persist for long periods of time after the cessation of drug taking. In addition to typical antipsychotics, DIP may be caused by gastrointestinal prokinetics, calcium channel blockers, atypical antipsychotics, and antiepileptic drugs. The clinical manifestations of DIP are classically described as bilateral and symmetric parkinsonism without tremor at rest. However, about half of DIP patients show asymmetrical parkinsonism and tremor at rest, making it difficult to differentiate DIP from PD. The pathophysiology of DIP is related to drug-induced changes in the basal ganglia motor circuit secondary to dopaminergic receptor blockade. Since these effects are limited to postsynaptic dopaminergic receptors, it is expected that presynaptic dopaminergic neurons in the striatum will be intact. Dopamine transporter (DAT) imaging is useful for diagnosing presynaptic parkinsonism. DAT uptake in the striatum is significantly decreased even in the early stage of PD, and this characteristic may help in differentiating PD from DIP. DIP may have a significant and longstanding effect on patients' daily lives, and so physicians should be cautious when prescribing dopaminergic receptor blockers and should monitor patients' neurological signs, especially for parkinsonism and other movement disorders. PMID:22523509
Shin, Hae-Won
2012-01-01
376
SciTech Connect
Autophagy is a mechanism to digest cells' own components, and its importance in many physiological and pathological processes is being recognized. But the molecular mechanism that regulates autophagy is not understood in detail. In the present study, we found that cholesterol depletion induces macroautophagy. The cellular cholesterol in human fibroblasts was depleted either acutely using 5 mM methyl-{beta}-cyclodextrin or 10-20 {mu}g/ml nystatin for 1 h, or metabolically by 20 {mu}M mevastatin and 200 {mu}M mevalonolactone along with 10% lipoprotein-deficient serum for 2-3 days. By any of these protocols, marked increase of LC3-II was detected by immunoblotting and by immunofluorescence microscopy, and the increase was more extensive than that caused by amino acid starvation, i.e., incubation in Hanks' solution for several hours. The induction of autophagic vacuoles by cholesterol depletion was also observed in other cell types, and the LC3-positive membranes were often seen as long tubules, >50 {mu}m in length. The increase of LC3-II by methyl-{beta}-cyclodextrin was suppressed by phosphatidylinositol 3-kinase inhibitors and was accompanied by dephosphorylation of mammalian target of rapamycin. By electron microscopy, autophagic vacuoles induced by cholesterol depletion were indistinguishable from those seen after amino acid starvation. These results demonstrate that a decrease in cholesterol activates autophagy by a phosphatidylinositol 3-kinase-dependent mechanism.
Cheng, Jinglei [Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Ohsaki, Yuki [Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Tauchi-Sato, Kumi [Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Fujita, Akikazu [Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan); Fujimoto, Toyoshi [Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya 466-8550 (Japan)]. E-mail: [email protected]
2006-12-08
377
PubMed
An epileptoid attack induced by orthostatic hypotension seen in a 72-year-old man was reported. The patient had been suffering from progressive autonomic failure with parkinsonism for six years and he had severe orthostatic hypotension, syncope and generalized convulsion when he stood up. The convulsion sometimes associated with urinary incontinence, ceased immediately when he lay down although he remained drowsy for a while. Occasionally the seizure ceased spontaneously and he regained consciousness even while he was kept standing. On lying position his blood pressure was 167/88 mmHg and no abnormality was seen in electroencephalogram. When he was tilted up to 50 degrees his blood pressure fell to 70/46 mmHg, and he became unconscious followed by jaw twitching and generalized clonic seizure. Electroencephalogram during seizure showed sharp wave and rhythmic spikes. Other laboratory examination revealed diffuse and severe autonomic dysfunction and slight cerebral atrophy on brain CT scanning. He was treated with diphenylhydantoin 300 mg/day and the seizure responded partially. The reasons why the patient's seizure was thought to be epileptic rather than the convulsive syncope were as follows: the type of the seizure was similar to an epileptic generalized convulsion, the seizure and unconsciousness ceased spontaneously even during standing position, the seizure and impaired consciousness partially responded to diphenylhydantoin administration. The underlying pathophysiology of the seizure was thought to be transient cerebral hypoperfusion induced by orthostatic hypotension. PMID:2625024
Sakakibara, R; Kita, K; Hattori, T; Hirayama, K
1989-11-01
378
PubMed
Radiation-induced neuropathy is commonly observed among oncological patients. Radiation can affect the nervous tissue directly or indirectly by inducing vasculopathy or dysfunction of internal organs. Symptoms may be mild and reversible (e.g., pain, nausea, vomiting, fever, drowsiness, fatigue, paresthesia) or life-threatening (cerebral oedema, increased intracranial pressure, seizures). Such complications are clinically divided into peripheral (plexopathies, neuropathies of spinal and cranial nerves) and central neuropathy (myelopathy, encephalopathy, cognitive impairment). The degree of neuronal damages primarily depends on the total and fractional radiation dose and applied therapeutic methods. The conformal and megavoltage radiotherapy seems to be the safeties ones. Diagnostic protocol includes physical examination, imaging (in particular magnetic resonance), electromyography, nerve conduction study and sometimes histological examination. Prevention and early detection of neurological complications are necessary in order to prevent a permanent dysfunction of the nervous system. Presently their treatment is mostly symptomatic, but in same cases a surgical intervention is required. An experimental and clinical data indicates some effectiveness of different neuroprotective agents (e.g. anticoagulants, vitamin E, hyperbaric oxygen, pentoxifylline, bevacizumab, methylphenidate, donepezil), which should be administered before and/or during radiotherapy. PMID:24490474
Kolak, Agnieszka; Staros?awska, Elzbieta; Kieszko, Dariusz; Cisek, Pawe?; Patyra, Krzysztof Ireneusz; Surdyka, Dariusz; Dobrzy?ska-Rutkowska, Aneta; ?opacka-Szatan, Karolina; Burdan, Franciszek
2013-12-01
379
PubMed Central
Autoimmune thyroid diseases (AITD) are complex diseases that develop as a result of interactions between genetic, epigenetic, and environmental factors. Significant progress has been made in our understanding of the genetic and environmental triggers contributing to AITD. The major environmental triggers of AITD include iodine, smoking, medications, pregnancy, and possibly stress. In this review we will focus on two well-documented environmental triggers of AITD, hepatitis C virus (HCV) infection and interferon alpha (IFNa) therapy. Chronic HCV infection has been shown to be associated with increased incidence of clinical and subclinical autoimmune thyroiditis (i.e. the presence of thyroid antibodies in euthyroid subjects). Moreover, IFNa therapy of chronic HCV infection is associated with subclinical or clinical thyroiditis in up to 40% of cases which can be autoimmune, or non-autoimmune thyroiditis. In some cases interferon induced thyroiditis (IIT) in chronic HCV patients may result in severe symptomatology necessitating discontinuation of therapy. While the epidemiology and clinical presentation of HCV and interferon induced thyroiditis have been well characterized, the mechanisms causing these conditions are still poorly understood. PMID:20022216
Tomer, Yaron
2009-01-01
380
PubMed Central
Interferon-alpha (IFN?) is used for the treatment of various disorders, most notable chronic hepatitis C virus (HCV) infection. One of the commonest side effects of IFN? therapy is thyroiditis, with up to 40% of HCV patients on IFN? developing clinical or subclinical disease. In some cases interferon induced thyroiditis (IIT) may result in severe symptomatology necessitating discontinuation of therapy. IIT can manifest as clinical autoimmune thyroiditis, presenting with symptoms of classical Hashimoto’s thyroiditis or Graves’ disease, or as non-autoimmune thyroiditis. Non-autoimmune thyroiditis can manifest as destructive thyroiditis, with early thyrotoxicosis and later hypothyroidism, or as non-autoimmune hypothyroidism. While the epidemiology and clinical presentation of IIT have been well characterized the mechanisms causing IIT are still poorly understood. It is likely that the hepatitis C virus (HCV) itself plays a role in the disease, as the association between HCV infection and thyroiditis is well established. It is believed that IFN? induces thyroiditis by both immune stimulatory effects and by direct effects on the thyroid. Early detection and therapy of this condition are important in order to avoid complications of thyroid disease such as cardiac arrhythmias. PMID:19942147
Menconi, Francesca
2009-01-01
381
PubMed Central
Objective. Drugs can induce almost the entire spectrum of hematologic disorders, affecting white cells, red cells, platelets, and the coagulation system. This paper aims to emphasize the broad range of drug-induced hematological syndromes and to highlight some of the newer drugs and syndromes. Methods. Medline literature on drug-induced hematologic syndromes was reviewed. Most reports and reviews focus on individual drugs or cytopenias. Results. Drug-induced syndromes include hemolytic anemias, methemoglobinemia, red cell aplasia, sideroblastic anemia, megaloblastic anemia, polycythemia, aplastic anemia, leukocytosis, neutropenia, eosinophilia, immune thrombocytopenia, microangiopathic syndromes, hypercoagulability, hypoprothrombinemia, circulating anticoagulants, myelodysplasia, and acute leukemia. Some of the classic drugs known to cause hematologic abnormalities have been replaced by newer drugs, including biologics, accompanied by their own syndromes and unintended side effects. Conclusions. Drugs can induce toxicities spanning many hematologic syndromes, mediated by a variety of mechanisms. Physicians need to be alert to the potential for iatrogenic drug-induced hematologic complications. PMID:19960059
Mintzer, David M.; Billet, Shira N.; Chmielewski, Lauren
2009-01-01
382
PubMed Central
Studies indicate that high-grade serous ovarian carcinoma (HGSOC), the most common epithelial ovarian carcinoma histotype, originates from the fallopian tube epithelium (FTE). Risk factors for this cancer include reproductive parameters associated with lifetime ovulatory events. Ovulation is an acute inflammatory process during which the FTE is exposed to follicular fluid containing both pro- and anti-inflammatory molecules, such as interleukin-1 (IL1), tumor necrosis factor (TNF), and cortisol. Repeated exposure to inflammatory cytokines may contribute to transforming events in the FTE, with glucocorticoids exerting a protective effect. The global response of FTE cells to inflammatory cytokines or glucocorticoids has not been investigated. To examine the response of FTE cells and the ability of glucocorticoids to oppose this response, an immortalized human FTE cell line, OE-E6/E7, was treated with IL1?, dexamethasone (DEX), IL1? and DEX, or vehicle and genome-wide gene expression profiling was performed. IL1? altered the expression of 47 genes of which 17 were reversed by DEX. DEX treatment alone altered the expression of 590 genes, whereas combined DEX and IL1? treatment altered the expression of 784 genes. Network and pathway enrichment analysis indicated that many genes altered by DEX are involved in cytokine, chemokine, and cell cycle signaling, including NF?? target genes and interacting proteins. Quantitative real time RT-PCR studies validated the gene array data for IL8, IL23A, PI3 and TACC2 in OE-E6/E7 cells. Consistent with the array data, Western blot analysis showed increased levels of PTGS2 protein induced by IL1? that was blocked by DEX. A parallel experiment using primary cultured human FTE cells indicated similar effects on PTGS2, IL8, IL23A, PI3 and TACC2 transcripts. These findings support the hypothesis that pro-inflammatory signaling is induced in FTE cells by inflammatory mediators and raises the possibility that dysregulation of glucocorticoid signaling could contribute to increased risk for HGSOC. PMID:24848801
Haw, Robin; Stein, Lincoln; Brown, Theodore J.
2014-01-01
383
PubMed
Sirolimus (SRL) is a macrolide immunosuppressant that has gained widespread use in organ transplantation. Its full spectrum of side-effects is yet to be defined. We describe herein three cases of SRL-induced angioedema (AE) in African-American (AA) primary renal allograft recipients who received SRL in combination with mycophenolate mofetil and steroids. In two cases, AE manifested after SRL was restarted after a period of discontinuation. The third case presented upon initial exposure to the drug. None of the patients was receiving any drug that has been previously associated with AE. Complete resolution occurred only after SRL was withdrawn. AE has not recurred in any of the patients during a follow-up period of up to 21 months. We conclude that AE is a previously unrecognized adverse event associated with SRL use. Close monitoring for this side-effect, especially in AA patients, is warranted. PMID:15147436
Wadei, Hani; Gruber, Scott A; El-Amm, Jose M; Garnick, James; West, Miguel S; Granger, Darla K; Sillix, Dale H; Migdal, Stephen D; Haririan, Abdolreza
2004-06-01
384
PubMed Central
Chemotherapeutic agents are used widely in clinical medicine for the treatment of conditions where diminution of the host immune response is a goal. The clinical use of immunosuppression is indicated for immunologically mediated disease, lymphoproliferative diseases, and prevention of graft rejection. Five categories of agents are useful for these purposes; they are ionizing irradiation, corticosteroids, biological alkylating agents, antilymphocyte sera and antimetabolites. While the specific molecular action of many of these drugs is known, how they affect cellular events in immune responses is less clear. One of the unfortunate sequelae of chemotherapy induced immunosuppression is an increased susceptibility of the host to opportunistic pathogens or malignancies. Specific methods are described for monitoring the various parameters of both humoral and cellular immunity. Studies of immunologic function in lymphoma patients and cardiac transplant patients treated with immunosuppressive drugs have shown specific defects in cell mediated immunity to herpes viruses which may relate to their increased susceptibility to infection by these agents. PMID:7037385
Rasmussen, L; Arvin, A
1982-01-01
385
This chapter represents the second part of a review in which the production and application of radiation-induced radicals in biological matter are discussed. In part one the general aspects of the four stages (physical, physicochemical, chemical and biological) of interaction of radiation with matter in general and biological matter in particular, were discussed. Here an overview is presented of modem technologies and theoretical methods available for studying these radiation effects. The relevance is highlighted of electron paramagnetic resonance spectroscopy and quantum chemical calculations with respect to obtaining structural information on bioradicals, and a survey is given of the research studies in this field. We also discuss some basic aspects of modem accelerator technologies which can be used for creating radicals and we conclude with an overview of applications of radiation processing in biology and related fields such as biomedical and environmental engineering, food technology, medicine and pharmacy.
Lahorte, Philippe; Mondelaers, Wim
386
PubMed Central
ABSTRACT Breast cancer represents the most frequent form of neoplasia in women worldwide, being responsible of 1.6% of annual deaths. Therefore, it is a major public health issue and research in this field should be a priority. Chemoterapics drugs are extremly potent tools, which alone or in association to radiotherapy, increase survival and lower the reccurrence rate of cancer, but their use can be limited by cardiotoxicity. Cardiotoxicity can appear early or late after therapy, and may vary from subclinical myocardial dysfunction to irreversible heart failure. Currently, cardiac dysfunction induced by chemotherapy is diagnosed through classical echocardiographic parameters. However, these cannot detect subtle, early changes of cardiac structure and function. Consequently, description of new methods, which could detect cardiac dysfunction in an early stage, becomes essential for detecting the group of patients at risk for irreversible heart failure and for monitoring the treatment. PMID:24023601
FLORESCU, Maria; CINTEZA, Mircea; VINEREANU, Dragos
2013-01-01
387
E-print Network
We study explosive synchronization, a phenomenon characterized by first-order phase transitions between incoherent and synchronized states in networks of coupled oscillators. While explosive synchronization has been the subject of many recent studies, in each case strong conditions on either the heterogeneity of the network, its link weights, or its initial construction are imposed to engineer a first-order phase transition. This raises the question of how robust explosive synchronization is in view of more realistic structural and dynamical properties. Here we show that explosive synchronization can be induced in mildly heterogeneous networks by the addition of quenched disorder to the oscillators' frequencies, demonstrating that it is not only robust to, but moreover promoted by, this natural mechanism. We support these findings with numerical and analytical results, presenting simulations of a real neural network as well as a self-consistency theory used to study synthetic networks.
Per Sebastian Skardal; Alex Arenas
2014-04-03
388
A project has been initiated to determine the feasibility of developing a complete airborne remote sensing system for rapidly mapping high concentration patches of bioluminescent organisms in the world's oceans. Conceptually, this system would be composed of a laser illuminator to induce bioluminescence and a low light level image intensifier for detection of light. Initial laboratory measurements consisted of using a 2-J flash lamp pulsed optical dye laser to excite bioluminescence in the marine dinoflagellate Pyrocustis lunula at ambient temperature using Rhodamine 6G as the lasing dye (585 nm) and a laser pulse width of 1 microsec. After a latency period of 15-20 msec, the bioluminescence maximum occurred in the blue (480 nm is the wavelength maximum for most dinoflagellate bioluminescence) with the peaking occurring approximately 65 msec after the laser pulse. Planned experiments will investigate the effect of different excitation wavelengths and energies at various temperatures and salinities of the cultures.
Hickman, G. D.; Lynch, R. V., III
1981-01-01
389
SciTech Connect
The objective of this project has been to develop a fundamental understanding of seismicity associated with energy production. Earthquakes are known to be associated with oil, gas, and geothermal energy production. The intent is to develop physical models that predict when seismicity is likely to occur, and to determine to what extent these earthquakes can be used to infer conditions within energy reservoirs. Early work focused on earthquakes induced by oil and gas extraction. Just completed research has addressed earthquakes within geothermal fields, such as The Geysers in northern California, as well as the interactions of dilatancy, friction, and shear heating, on the generation of earthquakes. The former has involved modeling thermo- and poro-elastic effects of geothermal production and water injection. Global Positioning System (GPS) receivers are used to measure deformation associated with geothermal activity, and these measurements along with seismic data are used to test and constrain thermo-mechanical models.
Segall, P.
1997-09-18
390
PubMed Central
Tumor-induced osteomalacia (TIO) is an acquired disorder of isolated renal phosphate wasting associated with tumors, typically of mesenchymal origin. Patients with TIO share similar biochemical and skeletal phenotypes with patients who have autosomal dominant hypophosphatemic rickets (ADHR) and X-linked hypophosphatemia. The study of TIO introduced the idea of the existence of circulating factors, referred to as ‘phosphatonins’, produced by the tumor, which act upon the kidney to reduce phosphate reabsorption. Although several factors have been identified, the phosphatonin FGF-23, also identified as the causative factor in ADHR, is currently the best characterized of these factors relative to phosphate handling. This review describes the importance of TIO in understanding phosphate homeostasis in the context of new endocrine interactions between the skeleton and the kidney. PMID:20228870
Farrow, Emily G; White, Kenneth E
2009-01-01
391
PubMed Central
Plants respond to herbivory through different defensive mechanisms. The induction of volatile emission is one of the important and immediate response of plants to herbivory. Herbivore-induced plant volatiles (HIPVs) are involved in plant communication with natural enemies of the insect herbivores, neighboring plants, and different parts of the damaged plant. Release of a wide variety of HIPVs in response to herbivore damage and their role in plant-plant, plant-carnivore and intraplant communications represents a new facet of the complex interactions among different trophic levels. HIPVs are released from leaves, flowers, and fruits into the atmosphere or into the soil from roots in response to herbivore attack. Moreover, HIPVs act as feeding and/or oviposition deterrents to insect pests. HIPVs also mediate the interactions between the plants and the microorganisms. This review presents an overview of HIPVs emitted by plants, their role in plant defense against herbivores and their implications for pest management. PMID:22105032
War, Abdul Rashid; Sharma, Hari Chand; Paulraj, Michael Gabriel; War, Mohd Yousf; Ignacimuthu, Savarimuthu
2011-01-01
392
PubMed
Aminoglycosides are among the oldest antibiotics available to treat serious infections caused by primarily, Gram-negative bacteria. The most commonly utilized parenteral agents in this class include gentamicin, tobramycin and amikacin. Aminoglycosides are concentration-dependent, bactericidal agents that undergo active transport into the cell where they inhibit protein synthesis on the 30S subunit of the bacterial ribosome. As the use of aminoglycosides became more widespread, the toxic effects of these agents, most notably ototoxicity and nephrotoxicity, became more apparent. When other, safer, antimicrobial agents became available, the use of aminoglycosides sharply declined. The development of multi-drug resistance among bacteria has now lead clinicians to reexamine the role of the aminoglycosides in the treatment of serious infections. This review will revisit the mechanism and risk factors for the development of aminoglycoside-induced nephrotoxicity, as well as strategies to prevent patients from developing nephrotoxicity. PMID:25199523
Wargo, Kurt A; Edwards, Jonathan D
2014-12-01
393
We consider a phase transition induced by the growth of Q-balls in a false vacuum. Such a transition could occur in the early universe in the case of broken supersymmetry with a metastable false vacuum. Small Q-balls with a negative potential energy can grow in a false vacuum by accretion of global charge until they reach critical size, expand, and cause a phase transition. We consider the growth of Q-balls from small to large, using the Bethe-Salpeter equation to describe small charge solitons and connecting to the growth of larger solitons for which the semiclassical approximation is reliable. We thus test the scenario in a simplified example inspired by supersymmetric extensions of the standard model.
Pearce, Lauren
2012-06-01
394
PubMed
We examined the effect of occlusal disharmony in senescence-accelerated (SAMP8) mice on plasma corticosterone levels, spatial learning in the water maze, fos induction, hippocampal neuron number, expression of glucocorticoid receptors (GR) and glucocorticoid receptor messenger ribonucleic acid (GRmRNA) in hippocampus and inhibitor of glucocorticoid (metyrapone). Bite-raised aged mice had significantly greater plasma corticosterone levels than age-matched control mice as well as impaired spatial memory and decreased Fos induction and a number of neurons in hippocampus. GR and GRmRNA expressions were significantly decreased in aged bite-raised mice compared with age-matched control mice. Pretreatment with metyrapone inhibited not only the bite-raised induced increase in plasma corticosterone levels, but also the reduction in the number of hippocampal neurons and impaired spatial learning. These datas suggest that the bite-raised condition may enhance the aging process in hippocampus, thereby leading to impairment of spatial memory by stress. PMID:18833910
Iinuma, Mitsuo; Ichihashi, Yukiko; Hioki, Yoko; Kurata, Chika; Tamura, Yasuo; Kubo, Kin-ya
2008-05-01
395
PubMed Central
Patients receiving radiotherapy or chemotherapy will receive some degree of oral mucositis The incidence of oral mucositis was especially high in patients: (i) With primary tumors in the oral cavity, oropharynx, or nasopharynx; (ii) who also received concomitant chemotherapy; (iii) who received a total dose over 5,000 cGy; and (iv) who were treated with altered fractionation radiation schedules. Radiation-induced oral mucositis affects the quality of life of the patients and the family concerned. The present day management of oral mucositis is mostly palliative and or supportive care. The newer guidelines are suggesting Palifermin, which is the first active mucositis drug as well as Amifostine, for radiation protection and cryotherapy. The current management should focus more on palliative measures, such as pain management, nutritional support, and maintenance, of good oral hygiene PMID:20668585
PS, Satheesh Kumar; Balan, Anita; Sankar, Arun; Bose, Tinky
2009-01-01
396
PubMed Central
Atopic dermatitis (AD) is characterized by chronic highly pruritic and relapsing inflammatory skin lesions. Despite its growing prevalence, therapeutic treatments remain limited. Natural immune modulators from herbal extracts or derivatives may be useful for treating AD symptoms. This study examined the effect of 7,8,4?-trihydroxyisoflavone (7,8,4?-THIF), a metabolite of soy isoflavone daidzin, on AD-like symptoms. Repeated epicutaneous application of 2,4-dinitrochlorobenzene (DNCB) was performed on the ear and dorsal skin of NC/Nga mice to induce AD-like symptoms and skin lesions, and 7,8,4?-THIF (200 and 400 nmol) or tacrolimus (100 µg) was applied topically for 3 weeks to assess their anti-pruritic effects. We found that 7,8,4?-THIF alleviated DNCB-induced AD-like symptoms as quantified by skin lesion, dermatitis score, ear thickness, and scratching behavior. Histopathological analysis demonstrated that 7,8,4?-THIF decreased DNCB-induced eosinophil and mast cell infiltration into skin lesions. We also found that 7,8,4?-THIF significantly alleviated DNCB-induced loss of water through the epidermal layer. In addition to reducing the DNCB-induced increase in serum IgE, 7,8,4?-THIF also lowered skin lesion levels of the chemokine thymus and activation regulated chemokine; Th2 cytokines interleukin (IL)-4, IL-5, and IL-13; and Th1 cytokines IL-12 and interferon-?. These results suggest that 7,8,4?-THIF might be a potential therapeutic candidate for the treatment of atopic dermatitis. PMID:25170825
Kim, Heejung; Kim, Jong Rhan; Kang, Heerim; Choi, Jinhwan; Yang, Hee; Lee, Pomjoo; Kim, Jiyoung; Lee, Ki Won
2014-01-01
397
PubMed Central
About 25% of high-grade cervical intraepithelial neoplasias (CIN2/3) caused by human papillomavirus serotype 16 (HPV16) undergo complete spontaneous regression. However, to date, therapeutic vaccination strategies for HPV disease have yielded limited success when measured by their ability to induce robust peripheral blood T cell responses to vaccine antigen. We report marked immunologic changes in the target lesion microenvironment after intramuscular therapeutic vaccination targeting HPV16 E6/E7 antigens, in subjects with CIN2/3 who had modest detectable responses in circulating T lymphocytes. Histologic and molecular changes, including markedly (average threefold) increased intensity of CD8+ T cell infiltrates in both the stromal and epithelial compartments, suggest an effector response to vaccination. Postvaccination cervical tissue immune infiltrates included organized tertiary lymphoid-like structures in the stroma subjacent to residual intraepithelial lesions and, unlike infiltrates in unvaccinated lesions, showed evidence of proliferation induced by recognition of cognate antigen. At a molecular level, these histologic changes in the stroma were characterized by increased expression of genes associated with immune activation (CXCR3) and effector function (Tbet and IFN?), and were also associated with an immunologic signature in the overlying dysplastic epithelium. High-throughput T cell receptor sequencing of unmanipulated specimens identified clonal expansions in the tissue that were not readily detectable in peripheral blood. Together, these findings indicate that peripheral therapeutic vaccination to HPV antigens can induce a robust tissue-localized effector immune response, and that analyses of immune responses at sites of antigen are likely to be much more informative than analyses of cells that remain in the circulation. PMID:24477000
Jotova, Iveta; Wu, T. C.; Wang, Chenguang; Desmarais, Cindy; Boyer, Jean D.; Tycko, Benjamin; Robins, Harlan S.; Clark, Rachael A.; Trimble, Cornelia L.
2014-01-01
398
PubMed
About 25% of high-grade cervical intraepithelial neoplasias (CIN2/3) caused by human papillomavirus serotype 16 (HPV16) undergo complete spontaneous regression. However, to date, therapeutic vaccination strategies for HPV disease have yielded limited success when measured by their ability to
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http://www.science.gov/topicpages/s/state+space+transitions.html
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#### Sample records for state space transitions
1. Multiple transition states and roaming in ion-molecule reactions: A phase space perspective
Mauguière, Frédéric A. L.; Collins, Peter; Ezra, Gregory S.; Farantos, Stavros C.; Wiggins, Stephen
2014-01-01
We provide a dynamical interpretation of the recently identified ‘roaming' mechanism for molecular dissociation reactions in terms of geometrical structures in phase space. These are NHIMs (Normally Hyperbolic Invariant Manifolds) and their stable/unstable manifolds that define transition states for ion-molecule association or dissociation reactions. The associated dividing surfaces rigorously define a roaming region of phase space, in which both reactive and non reactive trajectories can be trapped for arbitrarily long times.
2. The Jastrow antisymmetric geminal power in Hilbert space: Theory, benchmarking, and application to a novel transition state
SciTech Connect
Neuscamman, Eric
2013-11-21
The Jastrow-modified antisymmetric geminal power (JAGP) ansatz in Hilbert space successfully overcomes two key failings of other pairing theories, namely, a lack of inter-pair correlations and a lack of multiple resonance structures, while maintaining a polynomially scaling cost, variational energies, and size consistency. Here, we present efficient quantum Monte Carlo algorithms that evaluate and optimize the JAGP energy for a cost that scales as the fifth power of the system size. We demonstrate the JAGP’s ability to describe both static and dynamic correlation by applying it to bond stretching in H{sub 2}O, C{sub 2}, and N{sub 2} as well as to a novel, multi-reference transition state of ethene. JAGP’s accuracy in these systems outperforms even the most sophisticated single-reference methods and approaches that of exponentially scaling active space methods.
3. The Jastrow antisymmetric geminal power in Hilbert space: Theory, benchmarking, and application to a novel transition state
Neuscamman, Eric
2013-11-01
The Jastrow-modified antisymmetric geminal power (JAGP) ansatz in Hilbert space successfully overcomes two key failings of other pairing theories, namely, a lack of inter-pair correlations and a lack of multiple resonance structures, while maintaining a polynomially scaling cost, variational energies, and size consistency. Here, we present efficient quantum Monte Carlo algorithms that evaluate and optimize the JAGP energy for a cost that scales as the fifth power of the system size. We demonstrate the JAGP's ability to describe both static and dynamic correlation by applying it to bond stretching in H2O, C2, and N2 as well as to a novel, multi-reference transition state of ethene. JAGP's accuracy in these systems outperforms even the most sophisticated single-reference methods and approaches that of exponentially scaling active space methods.
4. Quantum phase transition in space
SciTech Connect
Damski, Bogdan; Zurek, Wojciech H
2008-01-01
A quantum phase transition between the symmetric (polar) phase and the phase with broken symmetry can be induced in a ferromagnetic spin-1 Bose-Einstein condensate in space (rather than in time). We consider such a phase transition and show that the transition region in the vicinity of the critical point exhibits scalings that reflect a compromise between the rate at which the transition is imposed (i.e., the gradient of the control parameter) and the scaling of the divergent healing length in the critical region. Our results suggest a method for the direct measurement of the scaling exponent {nu}.
5. Variational transition state theory
SciTech Connect
Truhlar, D.G.
1993-12-01
This research program involves the development of variational transition state theory (VTST) and semiclassical tunneling methods for the calculation of gas-phase reaction rates and selected applications. The applications are selected for their fundamental interest and/or their relevance to combustion.
6. Parametric State Space Structuring
NASA Technical Reports Server (NTRS)
Ciardo, Gianfranco; Tilgner, Marco
1997-01-01
Structured approaches based on Kronecker operators for the description and solution of the infinitesimal generator of a continuous-time Markov chains are receiving increasing interest. However, their main advantage, a substantial reduction in the memory requirements during the numerical solution, comes at a price. Methods based on the "potential state space" allocate a probability vector that might be much larger than actually needed. Methods based on the "actual state space", instead, have an additional logarithmic overhead. We present an approach that realizes the advantages of both methods with none of their disadvantages, by partitioning the local state spaces of each submodel. We apply our results to a model of software rendezvous, and show how they reduce memory requirements while, at the same time, improving the efficiency of the computation.
7. Primordial equation of state transitions
Aravind, Aditya; Lorshbough, Dustin; Paban, Sonia
2016-06-01
We revisit the physics of transitions from a general equation of state parameter to the final stage of slow-roll inflation. We show that it is unlikely for the modes comprising the cosmic microwave background to contain imprints from a preinflationary equation of state transition and still be consistent with observations. We accomplish this by considering observational consistency bounds on the amplitude of excitations resulting from such a transition. As a result, the physics which initially led to inflation likely cannot be probed with observations of the cosmic microwave background. Furthermore, we show that it is unlikely that equation of state transitions may explain the observed low multipole power suppression anomaly.
8. Universal Keplerian state transition matrix
NASA Technical Reports Server (NTRS)
Shepperd, S. W.
1985-01-01
A completely general method for computing the Keplerian state transition matrix in terms of Goodyear's universal variables is presented. This includes a new scheme for solving Kepler's problem which is a necessary first step to computing the transition matrix. The Kepler problem is solved in terms of a new independent variable requiring the evaluation of only one transcendental function. Furthermore, this transcendental function may be conveniently evaluated by means of a Gaussian continued fraction.
9. Progression of Space Transportation - Transitioning from Government to Commercial
NASA Technical Reports Server (NTRS)
Lueders, Kathy
2015-01-01
Spaceflight began as the exclusive province of government, however, starting in the 1980's the United States began to promote commercial participation in space transportation. Beginning with Executive policy and extending through legislation and regulation, NASA has embarked on facilitating the commercialization of space transportation to serve NASA needs and enable a non-NASA market place. This presentation provides background on the transition to commercial space transportation and the specific role NASA is playing in that endeavor.
10. Spectroscopic characterization of isomerization transition states.
PubMed
Baraban, Joshua H; Changala, P Bryan; Mellau, Georg Ch; Stanton, John F; Merer, Anthony J; Field, Robert W
2015-12-11
Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate a method for extracting transition state energies and properties from a characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern-a dip in the spacings of certain barrier-proximal vibrational levels-can be understood using the concept of effective frequency, ω(eff). The method is applied to the cis-trans conformational change in the S1 state of C2H2 and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders. PMID:26659051
11. Spectroscopic characterization of isomerization transition states
Baraban, Joshua H.; Changala, P. Bryan; Mellau, Georg Ch.; Stanton, John F.; Merer, Anthony J.; Field, Robert W.
2015-12-01
Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate a method for extracting transition state energies and properties from a characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern—a dip in the spacings of certain barrier-proximal vibrational levels—can be understood using the concept of effective frequency, ωeff. The method is applied to the cis-trans conformational change in the S1 state of C2H2 and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders.
12. On the occurrence of transition states in celestial mechanics.
PubMed
Jaffé, Charles; Uzer, T
2004-05-01
The transition state is a central concept in the study of chemical reactions. The basic idea is that state space (phase space) can be partitioned into two volumes; the first corresponding to reactants and the second to products. Chemists call the boundary between these two regions the transition state. The rate of a chemical reaction is then discussed in terms the of the flow across the transition state. These ideas can also be applied with good effect to celestial problems. This paper outlines the chemists' view of molecular dynamics and then illustrates its application to problem of transport in celestial mechanics. PMID:15220139
13. Space-time formulation of quantum transitions
Petrosky, T.; Ordonez, G.; Prigogine, I.
2001-12-01
In a previous paper we have studied dressed excited states in the Friedrichs model, which describes a two-level atom interacting with radiation. In our approach, excited states are distributions (or generalized functions) in the Liouville space. These states decay in a strictly exponential way. In contrast, the states one may construct in the Hilbert space of wave functions always present deviations from exponential decay. We have considered the momentum representation, which is applicable to global quantities (trace, energy transfer). Here we study the space-time description of local quantities associated with dressed unstable states, such as, the intensity of the photon field. In this situation the excited states become factorized in Gamow states. To go from local quantities to global quantities, we have to proceed to an integration over space, which is far from trivial. There are various elements that appear in the space-time evolution of the system: the unstable cloud that surrounds the bare atom, the emitted real photons and the Zeno photons,'' which are associated with deviations from exponential decay. We consider a Hilbert space approximation to our dressed excited state. This approximation leads already to decay close to exponential in the field surrounding the atom, and to a line shape different from the Lorentzian line shape. Our results are compared with numerical simulations. We show that the time evolution of an unstable state satisfies a Boltzmann-like H theorem. This is applied to emission and absorption as well as scattering. The existence of a microscopic H theorem is not astonishing. The excited states are nonequilibrium'' states and their time evolution leads to the emission of photons, which distributes the energy of the unstable state among the field modes.
14. Transition metal catalysis in confined spaces.
PubMed
Leenders, Stefan H A M; Gramage-Doria, Rafael; de Bruin, Bas; Reek, Joost N H
2015-01-21
Transition metal catalysis plays an important role in both industry and in academia where selectivity, activity and stability are crucial parameters to control. Next to changing the structure of the ligand, introducing a confined space as a second coordination sphere around a metal catalyst has recently been shown to be a viable method to induce new selectivity and activity in transition metal catalysis. In this review we focus on supramolecular strategies to encapsulate transition metal complexes with the aim of controlling the selectivity via the second coordination sphere. As we will discuss, catalyst confinement can result in selective processes that are impossible or difficult to achieve by traditional methods. We will describe the template-ligand approach as well as the host-guest approach to arrive at such supramolecular systems and discuss how the performance of the catalyst is enhanced by confining it in a molecular container. PMID:25340992
15. State Transitions in Semiarid Landscapes
Phillips, J. D.
2012-04-01
The U.S. Department of Agriculture has developed a large number of state-and-transition models (STM) to predict and interpret changes in vegetation communities in drylands of the southwestern U.S. These are represented as box-and-arrow models indicating potential changes in response to various combinations of management practices and environmental forcings. Analysis of the 320 STMs developed for areas within the state of Texas reveals two important aspects of environmental change in semiarid environments. First, the STMs are highly local—they are specific to very particular combinations of landform, soil, and climate. This is consistent with the perfect landscape concept in geomorphology, which emphasizes the irreducible importance of geographically and historically contingent local factors in addition to universal laws or principles in determining the state or condition of landscapes. Second, analysis of the STMs using algebraic graph theory shows that a majority of them have structures that tend to amplify effects of change and disturbances. In many cases the STMs represent a form of self-organization characterized by the potential of divergent behavior rather than convergence toward a dominant pattern or outcome. These results indicate that geomorphic, hydrologic, and ecological responses to climate and land use change are likely to be highly variable and idiosyncratic, both within and between semiarid landscapes of Texas.
16. Transitioning NASA Space Operations to Commercial Services
NASA Technical Reports Server (NTRS)
Gilbert, Charlene E.
1998-01-01
Major considerations associated with "Transitioning NASA Space Operations to Commercial Services" are presented in viewgraph form. Specific topics include: 1) Government use of commercial frequencies vs. commercial use of commercial frequencies for government use; 2) Commercial use of government frequencies; 3) Government vs commercial: Access techniques, data formats, and modulation and coding; 4) Government need for multiple sources: backup and competition; 5) Government in perceived competition with commercial service providers if TDRSS is used for commercial purposes; and 6) Coordination required among plans for CSOC, NSCP, and satellite industry.
17. Periodic-orbit formula for quantum reactions through transition states
SciTech Connect
Schubert, Roman; Goussev, Arseni; Wiggins, Stephen; Waalkens, Holger
2010-07-15
Transition state theory forms the basis of computing reaction rates in chemical and other systems. Recently, it has been shown how transition state theory can rigorously be realized in phase space by using an explicit algorithm. The quantization has been demonstrated to lead to an efficient procedure to compute cumulative reaction probabilities and the associated Gamov-Siegert resonances. In this paper, these results are used to express the cumulative reaction probability as an absolutely convergent sum over periodic orbits contained in the transition state.
18. Longitudinal space charge effects near transition
SciTech Connect
Pozdeyev,E.; Rodriguez, J.A.; Marti, F.; York, R.C.
2009-05-04
Experimental and numerical studies of the longitudinal beam dynamics in the Small Isochronous Ring (SIR) at Michigan State University revealed a fast, space-charge driven instability that did not fit the model of the negative mass instability. This paper proposes a simple analytical model explaining these results. Also, the paper compares the model to result s of experimental and numerical studies of the longitudinal beam dynamics in SIR.
19. Challenges for Transitioning Science Research to Space Weather Applications
NASA Technical Reports Server (NTRS)
Spann, James
2013-01-01
Effectively transitioning science knowledge to useful applications relevant to space weather has become important. The effort to transition scientific knowledge to a useful application is not a research nor is it operations, but an activity that connects two. Successful transitioning must be an intentional effort with a clear goal and measureable outcome. This talk will present proven methodologies that have been demonstrated to be effective, and how in the current environment those can be applied to space weather transition efforts.
20. Quasi-classical models of transition state absorption or emission
Lee, Soo-Y.; Pollard, W. Thomas; Mathies, Richard A.
1989-11-01
By making a short-time approximation to the correlation function in the quantum result for transition state absorption (or emission) we obtain the Lorentzian and reflection results as integrals of simple configuration space functions. These and the time-integrated quantum results are used to derive and unify the following descriptions of transition-state absorption: (a) the classical model of Bersohn and Zewail, (b) the time-dependent wave mechanical description by Agrawal, Mohan and Sathyamurthy, (c) the classical trajectory approach by Polanyi and coworkers and (d) the time-independent quantum-mechanical description by Engel, Bacic, Schinke and Shapiro.
1. Operationalizing resilience using state and transition models
Technology Transfer Automated Retrieval System (TEKTRAN)
In management, restoration, and policy contexts, the notion of resilience can be confusing. Systematic development of conceptual models of ecological state change (state transition models; STMs) can help overcome semantic confusion and promote a mechanistic understanding of resilience. Drawing on ex...
2. Radiative transitions of heavy quarkonium states
SciTech Connect
De Fazio, Fulvia
2009-03-01
We study radiative decays of heavy QQ states, both for Q=c and Q=b, using an effective Lagrangian approach which exploits spin symmetry for such states. We use existing data on radiative quarkonium transitions to predict some unmeasured decay rates. We also discuss how these modes can be useful to understand the structure of X(3872)
3. Soil, resilience, and state and transition models
Technology Transfer Automated Retrieval System (TEKTRAN)
State and transition models are based on the assumption that less resilient systems are more susceptible to state changes. The objective of this paper is to show how two different types of soil properties contribute to resilience through their direct and indirect effects on ecosystem processes, and ...
4. United States Space Explorations 1958
NASA Technical Reports Server (NTRS)
1962-01-01
United States Space Explorations 1958. The film describes preparation and launch of five satellites and two space probes during 1958. On January 31, a Jupiter vehicle launched Explorer I into space. Data from this satellite was used to identify the van Allen radiation belts. On March 17, a Vanguard I rocket launched an Earth satellite with solar batteries. Data from the mission was used to determine that the Earth is slightly pear-shaped. On March 26, Explorer III was launched to further study the van Allen belts, micrometeoroid impacts, and internal and external temperatures. Explorer IV, launched on July 26, was intended to study radiation and temperature data. A lunar probe, ABLE I, was intended to measure radiation, magnetic fields of Earth and the Moon, density of micrometeoric matter, and internal temperatures. A four-stage rocket was used in the launch. However, a turbo-pump failed and the liquid oxygen pump stopped, resulting in a failed mission. On October 10, Pioneer I was launched by an ABLE vehicle. First and second stage velocity was less than desired and the probe did not leave Earth orbit. Attempts to attain escape velocity were unsuccessful. On December, a Jupiter boost vehicle was used to launch Juno II, with Pioneer III as the payload. Escape velocity was reached and Pioneer III left Earth's atmosphere. Failed launches, such as those of Vanguard boost vehicles and several Explorer satellites, also added to scientific knowledge. [Entire movie available on DVD from CASI as Doc ID 20070030963. Contact [email protected]
5. Successfully Transitioning Science Research to Space Weather Applications
NASA Technical Reports Server (NTRS)
Spann, James
2012-01-01
The awareness of potentially significant impacts of space weather on spaceand ground ]based technological systems has generated a strong desire in many sectors of government and industry to effectively transform knowledge and understanding of the variable space environment into useful tools and applications for use by those entities responsible for systems that may be vulnerable to space weather impacts. Essentially, effectively transitioning science knowledge to useful applications relevant to space weather has become important. This talk will present proven methodologies that have been demonstrated to be effective, and how in the current environment those can be applied to space weather transition efforts.
6. United States space transportation survey
NASA Technical Reports Server (NTRS)
Branscome, Darrel R.
1989-01-01
Different developmental paths for the U.S. space transportation fleet are discussed. Development of a purely cargo, unmanned space shuttle, using many components of the present manned space shuttle system, is presented. Future manned spacecraft solutions are discussed. Launch vehicle programs for unmanned missions are described. The Titan solid rocket motor upgrade is identified as the biggest improvement in this area. A return to a better balance between manned and unmanned launch systems for space transportation is predicted. The Titan, Delta, Scout, and Pegasus families of rockets are described. The need to upgrade this fleet in meeting the space challenges of the future is stressed.
7. Transition state theory for enzyme kinetics.
PubMed
Truhlar, Donald G
2015-09-15
This article is an essay that discusses the concepts underlying the application of modern transition state theory to reactions in enzymes. Issues covered include the potential of mean force, the quantization of vibrations, the free energy of activation, and transmission coefficients to account for nonequilibrium effect, recrossing, and tunneling. PMID:26008760
8. See Your State From Space!
USGS Publications Warehouse
U.S. Geological Survey
2008-01-01
Each of the 50 States in the United States is beautiful in its own way. That beauty can be seen from a unique perspective using satellite images taken from high above the Earth. These State images were created from multiple satellite images stitched together into one seamless image for each State. Names of major cities, administrative boundaries, and State flags have been added.
9. A Model of Mental State Transition Network
Xiang, Hua; Jiang, Peilin; Xiao, Shuang; Ren, Fuji; Kuroiwa, Shingo
Emotion is one of the most essential and basic attributes of human intelligence. Current AI (Artificial Intelligence) research is concentrating on physical components of emotion, rarely is it carried out from the view of psychology directly(1). Study on the model of artificial psychology is the first step in the development of human-computer interaction. As affective computing remains unpredictable, creating a reasonable mental model becomes the primary task for building a hybrid system. A pragmatic mental model is also the fundament of some key topics such as recognition and synthesis of emotions. In this paper a Mental State Transition Network Model(2) is proposed to detect human emotions. By a series of psychological experiments, we present a new way to predict coming human's emotions depending on the various current emotional states under various stimuli. Besides, people in different genders and characters are taken into consideration in our investigation. According to the psychological experiments data derived from 200 questionnaires, a Mental State Transition Network Model for describing the transitions in distribution among the emotions and relationships between internal mental situations and external are concluded. Further more the coefficients of the mental transition network model were achieved. Comparing seven relative evaluating experiments, an average precision rate of 0.843 is achieved using a set of samples for the proposed model.
10. Perimenopause as a neurological transition state.
PubMed
Brinton, Roberta D; Yao, Jia; Yin, Fei; Mack, Wendy J; Cadenas, Enrique
2015-07-01
Perimenopause is a midlife transition state experienced by women that occurs in the context of a fully functioning neurological system and results in reproductive senescence. Although primarily viewed as a reproductive transition, the symptoms of perimenopause are largely neurological in nature. Neurological symptoms that emerge during perimenopause are indicative of disruption in multiple estrogen-regulated systems (including thermoregulation, sleep, circadian rhythms and sensory processing) and affect multiple domains of cognitive function. Estrogen is a master regulator that functions through a network of estrogen receptors to ensure that the brain effectively responds at rapid, intermediate and long timescales to regulate energy metabolism in the brain via coordinated signalling and transcriptional pathways. The estrogen receptor network becomes uncoupled from the bioenergetic system during the perimenopausal transition and, as a corollary, a hypometabolic state associated with neurological dysfunction can develop. For some women, this hypometabolic state might increase the risk of developing neurodegenerative diseases later in life. The perimenopausal transition might also represent a window of opportunity to prevent age-related neurological diseases. This Review considers the importance of neurological symptoms in perimenopause in the context of their relationship to the network of estrogen receptors that control metabolism in the brain. PMID:26007613
11. Order of the transition versus space dimension in a family of cellular automata
Bidaux, Roger; Boccara, Nini; Chaté, Hugues
1989-03-01
A mean-field theory of (probabilistic) cellular automata is developed and used to select a typical local rule whose mean-field analysis predicts first-order phase transitions. The corresponding automaton is then studied numerically on regular lattices for space dimensions d between 1 and 4. At odds with usual beliefs on two-state automata with one absorbing phase, first-order transitions are indeed exhibited as soon as d>1, with closer quantitative agreement with mean-field predictions for high space dimensions. For d=1, the transition is continuous, but with critical exponents different from those of directed percolation.
12. Transition to the space shuttle operations era
NASA Technical Reports Server (NTRS)
1985-01-01
The tasks involved in the Space Shuttle Development Program are discussed. The ten major characteristics of an operational Shuttle are described, as well as the changes occurring in Shuttle processing, on-line operations, operations engineering, and support operations. A summary is given of tasks and goals that are being pursued in the effort to create a cost effective and efficient system.
13. State-Space Formulation for Circuit Analysis
ERIC Educational Resources Information Center
Martinez-Marin, T.
2010-01-01
This paper presents a new state-space approach for temporal analysis of electrical circuits. The method systematically obtains the state-space formulation of nondegenerate linear networks without using concepts of topology. It employs nodal/mesh systematic analysis to reduce the number of undesired variables. This approach helps students to…
14. State-transition diagrams for biologists.
PubMed
Bersini, Hugues; Klatzmann, David; Six, Adrien; Thomas-Vaslin, Véronique
2012-01-01
It is clearly in the tradition of biologists to conceptualize the dynamical evolution of biological systems in terms of state-transitions of biological objects. This paper is mainly concerned with (but obviously not limited too) the immunological branch of biology and shows how the adoption of UML (Unified Modeling Language) state-transition diagrams can ease the modeling, the understanding, the coding, the manipulation or the documentation of population-based immune software model generally defined as a set of ordinary differential equations (ODE), describing the evolution in time of populations of various biological objects. Moreover, that same UML adoption naturally entails a far from negligible representational economy since one graphical item of the diagram might have to be repeated in various places of the mathematical model. First, the main graphical elements of the UML state-transition diagram and how they can be mapped onto a corresponding ODE mathematical model are presented. Then, two already published immune models of thymocyte behavior and time evolution in the thymus, the first one originally conceived as an ODE population-based model whereas the second one as an agent-based one, are refactored and expressed in a state-transition form so as to make them much easier to understand and their respective code easier to access, to modify and run. As an illustrative proof, for any immunologist, it should be possible to understand faithfully enough what the two software models are supposed to reproduce and how they execute with no need to plunge into the Java or Fortran lines. PMID:22844438
15. State-Transition Diagrams for Biologists
PubMed Central
Bersini, Hugues; Klatzmann, David; Six, Adrien; Thomas-Vaslin, Véronique
2012-01-01
It is clearly in the tradition of biologists to conceptualize the dynamical evolution of biological systems in terms of state-transitions of biological objects. This paper is mainly concerned with (but obviously not limited too) the immunological branch of biology and shows how the adoption of UML (Unified Modeling Language) state-transition diagrams can ease the modeling, the understanding, the coding, the manipulation or the documentation of population-based immune software model generally defined as a set of ordinary differential equations (ODE), describing the evolution in time of populations of various biological objects. Moreover, that same UML adoption naturally entails a far from negligible representational economy since one graphical item of the diagram might have to be repeated in various places of the mathematical model. First, the main graphical elements of the UML state-transition diagram and how they can be mapped onto a corresponding ODE mathematical model are presented. Then, two already published immune models of thymocyte behavior and time evolution in the thymus, the first one originally conceived as an ODE population-based model whereas the second one as an agent-based one, are refactored and expressed in a state-transition form so as to make them much easier to understand and their respective code easier to access, to modify and run. As an illustrative proof, for any immunologist, it should be possible to understand faithfully enough what the two software models are supposed to reproduce and how they execute with no need to plunge into the Java or Fortran lines. PMID:22844438
16. QM/MM Analysis of Transition States and Transition State Analogues in Metalloenzymes.
PubMed
Roston, D; Cui, Q
2016-01-01
Enzymology is approaching an era where many problems can benefit from computational studies. While ample challenges remain in quantitatively predicting behavior for many enzyme systems, the insights that often come from computations are an important asset for the enzymology community. Here we provide a primer for enzymologists on the types of calculations that are most useful for mechanistic problems in enzymology. In particular, we emphasize the integration of models that range from small active-site motifs to fully solvated enzyme systems for cross-validation and dissection of specific contributions from the enzyme environment. We then use a case study of the enzyme alkaline phosphatase to illustrate specific application of the methods. The case study involves examination of the binding modes of putative transition state analogues (tungstate and vanadate) to the enzyme. The computations predict covalent binding of these ions to the enzymatic nucleophile and that they adopt the trigonal bipyramidal geometry of the expected transition state. By comparing these structures with transition states found through free energy simulations, we assess the degree to which the transition state analogues mimic the true transition states. Technical issues worth treating with care as well as several remaining challenges to quantitative analysis of metalloenzymes are also highlighted during the discussion. PMID:27498640
17. United States Space Explorations 1958
NASA Technical Reports Server (NTRS)
1962-01-01
The film describes preparation and launch of five satellites and two space probes during 1958. On January 31, a Jupiter vehicle launched Explorer I into space. Data from this satellite was used to identify the van Allen radiation belts. On March 17, a Vanguard I rocket launched an Earth satellite with solar batteries. Data from the mission was used to determine that the Earth is slightly pear-shaped. On March 26, Explorer III was launched to further study the van Allen belts, micrometeoroid impacts, and internal and external temperatures. Explorer IV, launched on July 26, was intended to study radiation and temperature data. A lunar probe, ABLE I, was intended to measure radiation, magnetic fields of Earth and the Moon, density of micrometeoric matter, and internal temperatures. A four-stage rocket was used in the launch. However, a turbo-pump failed and the liquid oxygen pump stopped, resulting in a failed mission. On October 10, Pioneer I was launched by an ABLE vehicle. First and second stage velocity was less than desired and the probe did not leave Earth orbit. Attempts to attain escape velocity were unsuccessful. On December, a Jupiter boost vehicle was used to launch Juno II, with Pioneer III as the payload. Escape velocity was reached and Pioneer III left Earth's atmosphere. Failed launches, such as those of Vanguard boost vehicles and several Explorer satellites, also added to scientific knowledge.
18. Quadratic Stochastic Operators with Countable State Space
Ganikhodjaev, Nasir
2016-03-01
In this paper, we provide the classes of Poisson and Geometric quadratic stochastic operators with countable state space, study the dynamics of these operators and discuss their application to economics.
19. The Applied Meteorology Unit: Nineteen Years Successfully Transitioning Research Into Operations for America's Space Program
NASA Technical Reports Server (NTRS)
Madura, John T.; Bauman, William H., III; Merceret, Francis J.; Roeder, William P.; Brody, Frank C.; Hagemeyer, Bartlett C.
2011-01-01
The Applied Meteorology Unit (AMU) provides technology development and transition services to improve operational weather support to America's space program . The AMU was founded in 1991 and operates under a triagency Memorandum of Understanding (MOU) between the National Aeronautics and Space Administration (NASA), the United States Air Force (USAF) and the National Weather Service (NWS) (Ernst and Merceret, 1995). It is colocated with the 45th Weather Squadron (45WS) at Cape Canaveral Air Force Station (CCAFS) and funded by the Space Shuttle Program . Its primary customers are the 45WS, the Spaceflight Meteorology Group (SMG) operated for NASA by the NWS at the Johnson Space Center (JSC) in Houston, TX, and the NWS forecast office in Melbourne, FL (MLB). The gap between research and operations is well known. All too frequently, the process of transitioning research to operations fails for various reasons. The mission of the AMU is in essence to bridge this gap for America's space program.
20. Transition From NASA Space Communication Systems to Commerical Communication Products
NASA Technical Reports Server (NTRS)
1994-01-01
Transitioning from twenty-five years of space communication system architecting, engineering and development to creating and marketing of commercial communication system hardware and software products is no simple task for small, high-tech system engineering companies whose major source of revenue has been the U.S. Government. Yet, many small businesses are faced with this onerous and perplexing task. The purpose of this talk/paper is to present one small business (LinCom) approach to taking advantage of the systems engineering expertise and knowledge captured in physical neural networks and simulation software by supporting numerous National Aeronautics and Space Administration (NASA) and the Department of Defense (DoD) projects, e.g., Space Shuttle, TDRSS, Space Station, DCSC, Milstar, etc. The innovative ingredients needed for a systems house to transition to a wireless communication system products house that supports personal communication services and networks (PCS and PCN) development in a global economy will be discussed. Efficient methods for using past government sponsored space system research and development to transition to VLSI communication chip set products will be presented along with notions of how synergy between government and industry can be maintained to benefit both parties.
1. Spin state transitions in cobaltites: spectroscopic perspective
Hao Tjeng, Liu
2010-03-01
The class of cobalt-oxide based materials has attracted increasing interest in the last decade. A key aspect of the cobaltites that distinguishes them clearly from the Cu, Ni, and Mn oxides is the spin state degree of freedom of the Co3+ and Co4+ ions: the ions can be low spin, high spin, and perhaps even intermediate spin. This aspect comes on top of the orbital and charge degrees of freedom that already make the Cu, Ni, Mn systems so exciting. It is, however, also precisely this aspect that causes considerable debate in the literature. In this presentation we would like to show how synchrotron based soft-x-ray spectroscopies can successfully resolve the local electronic structure of the Co ions and thus contribute to a better understanding of the physical properties of the cobaltites. In particular, we will address the issue of spin state transitions, metal insulator transitions and the newly proposed spin-blockade phenomenon in several layered cobalt materials. --- Work done in collaboration with Z. Hu, M.W. Haverkort, C.F. Chang, H. Wu, T. Burnus, Y.Y. Chin, N. Hollmann, C. Schussler- Langeheine, M. Benomar, T. Lorenz, D.I. Khomskii (Univ. Cologne), A. Tanaka (Univ. Hiroshima), S.N. Barilo (NAS, Minsk), J. Cezar, N.B. Brookes (ESRF-Grenoble), H.H. Hsieh, H.J. Lin, C.T. Chen (NSRRC-Hsinchu). Supported by the DFG through SFB 608.
2. Spectral presheaves as quantum state spaces.
PubMed
Döring, Andreas
2015-08-01
For each quantum system described by an operator algebra [Formula: see text] of physical quantities, we provide a (generalized) state space, notwithstanding the Kochen-Specker theorem. This quantum state space is the spectral presheaf [Formula: see text]. We formulate the time evolution of quantum systems in terms of Hamiltonian flows on this generalized space and explain how the structure of the spectral presheaf [Formula: see text] geometrically mirrors the double role played by self-adjoint operators in quantum theory, as quantum random variables and as generators of time evolution. PMID:26124247
3. Transit Imaging and Spectroscopy with the James Webb Space Telescope
NASA Technical Reports Server (NTRS)
Clampin, Mark
2008-01-01
The James Webb Space Telescope (JWST) is a large aperture (6.5 meter), cryogenic space telescope with a suite of near and mid-infrared instruments covering the wavelength range of 0.6 microns to 28 microns. JWST's primary science goal is to detect and characterize the first galaxies. It will also study the assembly of galaxies, star formation, and the formation of evolution of planetary systems. Recent progress in hardware development for the observatory will be presented, including a discussion of the status of JWST's optical system and Beryllium mirror fabrication, progress with sunshield prototypes, and recent changes in the integration and test configuration. We also review the expected scientific performance of the observatory for observations of exosolar planets by means of transit imaging and spectroscopy. We will review the capabilities of each science instrument, and discuss the performance of each mode, with reference to current transiting systems.
4. International Space Station: Transitional Platform for Moon and Mars
NASA Technical Reports Server (NTRS)
Greeniesen, Michael C.
2006-01-01
Humans on the path to Mars are employing the Space Station to better understand the Life Sciences issues during long duration space flight. In this phase the problems, for example, of bone loss, skeletal muscle atrophy and radiation will be prioritized for countermeasure development. This presentation will feature NASA's critical path to the Moon and Mars as the initial blueprint for addressing these Human Life Sciences challenges necessary to accomplish a successful Mars transit, surface exploration and return to Earth. A Moon base will be the test bed for resolving the engineering obstacles for later establishment of the Mars Crew Habitat. Current engineering concept scenarios for Moon and Mars bases plus Mars transit vehicles will receive the final focus.
5. Universal transition state scaling relations for (de)hydrogenation over transition metals.
PubMed
Wang, S; Petzold, V; Tripkovic, V; Kleis, J; Howalt, J G; Skúlason, E; Fernández, E M; Hvolbæk, B; Jones, G; Toftelund, A; Falsig, H; Björketun, M; Studt, F; Abild-Pedersen, F; Rossmeisl, J; Nørskov, J K; Bligaard, T
2011-12-14
We analyse the transition state energies for 249 hydrogenation/dehydrogenation reactions of atoms and simple molecules over close-packed and stepped surfaces and nanoparticles of transition metals using Density Functional Theory. Linear energy scaling relations are observed for the transition state structures leading to transition state scaling relations for all the investigated reactions. With a suitable choice of reference systems the transition state scaling relations form a universality class that can be approximated with one single linear relation describing the entire range of reactions over all types of surfaces and nanoclusters. PMID:21996683
6. Transitioning Space Weather Models Into Operations: The Basic Building Blocks
2009-10-01
New and improved space weather models that provide real-time or near-real time operational awareness to the long list of customers that the NOAA Space Weather Prediction Center (SWPC) serves are critically needed. Recognizing this, SWPC recently established a Developmental Testbed Center (DTC [see Kumar, 2009]) at which models will be vetted for operational use. What characteristics should models have if they are to survive this transition? The difficulties around the implementation of real-time models are many. From the stability of the data input (frequently coming from third parties) to the elevated information technology (IT) security atmosphere present everywhere, scientists and developers are confronting a series of challenges in the implementation of their models. Quinn et al. [2009] noted that “the transition challenges are numerous and require ongoing interaction between model developers and users.” However, the 2006 Report of the Assessment Committee for the National Space Weather Program (NSWP; see http://www.nswp.gov/nswp_acreport0706.pdf) found that “there is an absence of suitable connection[s] for ‘academia-to-operations’ knowledge transfer and for the transition of research to operations in general.”
7. State space control of frequency standards
Koppang, Paul A.
2016-06-01
Discrete time control systems are widely used in time and frequency applications. Control systems can be designed to reduce phase and frequency offsets to a given reference either more or less aggressively depending on overall system needs. There are many methods available to aid in designing control systems, including techniques based on state space system models. Several state space control design methods will be shown. The control concepts covered in this paper are pole placement, minimum control effort, and linear quadratic Gaussian. The effects of steering limits on system performance will also be discussed.
8. "Show me your impact": evaluating transitional justice in contested spaces.
PubMed
Duggan, Colleen
2012-02-01
This paper discusses some of the most significant challenges and opportunities for evaluating the effects of programs in support of transitional justice - the field that addresses how post-conflict or post authoritarian societies deal with legacies of wide spread human rights violations. The discussion is empirically grounded in a case study that assesses the efforts of the International Development Research Centre (IDRC) and one of its Guatemalan partners to evaluate the effects of a museum exposition that is attempting to recast historic memory and challenge racist attitudes in post-conflict Guatemala. The paper argues that despite the increasing trend to fund transitional justice programs, many international aid donors are stuck in traditional and arguably orthodox paradigms of program evaluation. This is having a negative effect not only upon the administration of aid but also upon how transitional justice research is perceived and valued by local populations. The case study experience indicates that there is no perfect evaluation model or approach for evaluating transitional justice programming - only choices to be made by commissioners of evaluation, evaluators, and those being evaluated. These are profoundly influenced by the extreme politics and moral values that define transitional justice settings as contested spaces in which calls to remember the tragic past must be balanced with aspirations to re-build a hopeful future. PMID:21190735
9. Space-based Search for Transiting Exoplanets Orbiting Bright Stars
Tsvetanov, Zlatan
At the current stage of research transiting planets hold the key to advancing our knowledge of exoplanets as they are the only targets that allow determination of many of the key plane-tary parameters. Because the employed techniques are differential (either photometry or spec-troscopy) and the planet is significantly fainter the host star the dominant limitation is simply the number of photons. This puts a very high premium on transiting planets with bright parent stars. The ExoPlanet Task Force recognized the high value of planets transiting bright stars and identified the need to perform a wide area space-based transit survey. In this presentation I will describe a program that addresses the ExoPTF recommendation by using the output of one of the instruments on the currently operating space mission STEREO. STEREO is the third mission in NASA's Solar Terrestrial Probes program. It uses two nearly identical spacecrafts -one on an Earth-leading orbit and one on an Earth-trailing orbit -each equipped with a suit of five small telescopes to provide a stereoscopic view of the coronal mass ejections (CME) as they propagate away from the Sun. As each of these telescopes observes a portion of the heliospehre, they also image the star field in the background. For the purposes of this study we will consider only the images obtained by the HI-1 instruments. Other instruments, although showing the stellar background as well, do not have the data output suitable for a search for transiting exoplanets. This project described here has the potential of delivering a number of very high value targets for follow-up studies with a wide range of facilities, both ground-based and space-based. It will provide a complete survey of all bright stars (<10m) for 18% of the sky. The photometric data series have the sensitivity to detect all transiting hot-Jupiters and other gas giants with periods up to ˜20 days and even some Neptune size planets orbiting bright and/or late type stars. On
10. How Accurate Are Transition States from Simulations of Enzymatic Reactions?
PubMed Central
2015-01-01
The rate expression of traditional transition state theory (TST) assumes no recrossing of the transition state (TS) and thermal quasi-equilibrium between the ground state and the TS. Currently, it is not well understood to what extent these assumptions influence the nature of the activated complex obtained in traditional TST-based simulations of processes in the condensed phase in general and in enzymes in particular. Here we scrutinize these assumptions by characterizing the TSs for hydride transfer catalyzed by the enzyme Escherichia coli dihydrofolate reductase obtained using various simulation approaches. Specifically, we compare the TSs obtained with common TST-based methods and a dynamics-based method. Using a recently developed accurate hybrid quantum mechanics/molecular mechanics potential, we find that the TST-based and dynamics-based methods give considerably different TS ensembles. This discrepancy, which could be due equilibrium solvation effects and the nature of the reaction coordinate employed and its motion, raises major questions about how to interpret the TSs determined by common simulation methods. We conclude that further investigation is needed to characterize the impact of various TST assumptions on the TS phase-space ensemble and on the reaction kinetics. PMID:24860275
11. Estimation of State Transition Probabilities: A Neural Network Model
Saito, Hiroshi; Takiyama, Ken; Okada, Masato
2015-12-01
Humans and animals can predict future states on the basis of acquired knowledge. This prediction of the state transition is important for choosing the best action, and the prediction is only possible if the state transition probability has already been learned. However, how our brains learn the state transition probability is unknown. Here, we propose a simple algorithm for estimating the state transition probability by utilizing the state prediction error. We analytically and numerically confirmed that our algorithm is able to learn the probability completely with an appropriate learning rate. Furthermore, our learning rule reproduced experimentally reported psychometric functions and neural activities in the lateral intraparietal area in a decision-making task. Thus, our algorithm might describe the manner in which our brains learn state transition probabilities and predict future states.
12. Interplanetary Transit Simulations Using the International Space Station
NASA Technical Reports Server (NTRS)
Charles, John B.; Arya, M.; Kundrot, C. E.
2010-01-01
We evaluated the space life sciences utility of the International Space Station (ISS) to simulate the outbound transit portion of missions to Mars and Near Earth Asteroids (NEA) to investigate biomedical and psychological aspects of such transits, to develop and test space operation procedures compatible with communication delays and outages, and to demonstrate and validate technologies and countermeasures. Two major categories of space life sciences activities can capitalize on ISS capabilities. The first includes studies that require ISS (or a comparable facility), typically for access to prolonged weightlessness. The second includes studies that do not strictly require ISS but can exploit it to maximize their scientific return more efficiently and productively than in ground-based simulations. For these studies, ISS offers a high fidelity analog for fundamental factors on future missions, such as crew composition, mission control personnel, operational tasks and workload, real-world risk, and isolation, and can mimic the effects of distance and limited accessibility. In addition to conducting Mars- and NEA-transit simulations on 6-month ISS increments, extending the current ISS increment duration from 6 months to 9 or even 12 months will provide opportunities for enhanced and focused research relevant to long duration Mars and NEA missions. Increasing the crew duration may pose little additional risk to crewmembers beyond that currently accepted on 6-month increments, but additional medical monitoring capabilities will be required beyond those currently used for ISS operations. Finally, while presenting major logistical challenges, such a simulation followed by a post-landing simulation of Mars exploration could provide quantitative evidence of capabilities in an actual mission. Thus, the use of ISS to simulate aspects of Mars and NEA missions seems practical. If it were to be implemented without major disruption of on-going ISS activities, then planning should
13. Fractal Complexity in Spontaneous EEG Metastable-State Transitions: New Vistas on Integrated Neural Dynamics
PubMed Central
Allegrini, Paolo; Paradisi, Paolo; Menicucci, Danilo; Gemignani, Angelo
2010-01-01
Resting-state EEG signals undergo rapid transition processes (RTPs) that glue otherwise stationary epochs. We study the fractal properties of RTPs in space and time, supporting the hypothesis that the brain works at a critical state. We discuss how the global intermittent dynamics of collective excitations is linked to mentation, namely non-constrained non-task-oriented mental activity. PMID:21423370
14. Recrossings and transition-state theory.
PubMed
Pritchard, Huw O
2005-02-24
When classical trajectory calculations are run on the two isomerization reactions NCCN <==> NCNC and CH3CN right harpoon over left harpoon CH3NC over a long period of time, up to ca. 0.2 micros each, one finds many more recrossings than actual reactive events. In these calculations a "recrossing" is defined as passage over the potential barrier separating the two species followed by return to the original side within 0.2 ps. For the C2N2 case there are about twice as many crossings of the barrier as there are genuine reactive events, and for CH3CN, there are about 10 times as many. Long-term mean residence times, tau(infinity)CN and tau(infinity)NC, in reactant and product wells are compared with the corresponding mean first passage times, tau1(CN) and tau1(NC), the latter found by terminating the trajectories at the first crossing of the barrier. For the NCCN <==> NCNC reaction, except at the lowest energies, the mean residence times are exactly twice the mean first passage times, implying that the transition-state theory transmission coefficient, as traditionally defined, should be kappa = 0.5. PMID:16833457
15. Space Surveillance: United States, Russia, and China
Seidelmann, P. K.
2012-06-01
With the launch of Sputnik, the United States and Russia began the process of tracking artificial satellites. This led to developments for observations, orbit determination, and catalog maintenance. The two countries followed somewhat different approaches to the same problem based on the available hardware and theoretical developments. As more sophisticated hardware and theories have been developed, progress has been made. However, new problems have developed because of debris, collision possibilities, and reentering objects. In addition, the range of spacecraft has increased to include geosynchronous orbits. In more recent times the European Space Agency (ESA) and China have become involved in various aspects of Space Surveillance. In 1994, the first meeting between United States and Russian experts in the field of space surveillance was held. Since then, seven more US Russia Space Surveillance Workshops have been held, with the addition of participants from ESA. Terry Alfriend has been the US Technical Chairman for many of these workshops. In 2009 a US China Space Surveillance Technical Interchange was held in Shanghai, China, and Terry was the US Technical Chairman.
16. Electric dipole transitions between Gamow-Teller and spin-dipole states
SciTech Connect
Suzuki, T.; Sagawa, H.; Van Giai, N.
1998-01-01
We study electric dipole transitions between Gamow-Teller (GT) and spin-dipole (SD) states. SD and GT excitations are calculated within the Hartree-Fock+Tamm-Dancoff approximation for {sup 48}Sc and {sup 90}Nb. The electric dipole transitions are found to be rather selective, and strong E1 transitions occur to some specific spin-dipole states. Calculated E1 transition strengths between GT and SD states are compared with the analytic sum rules within one-particle{endash}one-hole (1p-1h) configuration space and within both 1p-1h and 2p-2h model space. Possible implications for charge-exchange reactions may help to understand the quenching problem of spin excitations. {copyright} {ital 1998} {ital The American Physical Society}
17. Unified transition path and universal transition state for ZB to RS or WZ to RS high pressure phase transition
Miao, Maosheng
2005-07-01
We show that the previously proposed transition paths for high pressure phase transitions for semiconductor from zinc blende (ZB) to rocksalt (RS) and from wurtzite (WZ) to rocksalt can be unified and can be extended to transitions from various tetrahedrally bonded polytypes to rocksalt [1]. Our first principle pseudopotential calculations with density functional and constrained relaxation methods on SiC showed that the ZB to RS transition has the lowest transition barrier. Our calculations on ZB to RS transition path for other semiconductors including II-VI, III-V and group IV semiconductors, show that the position and the geometry of the transition state, the state that correspond to the transition barrier, are universal and do not depend on the chemical components of the system [2]. We also extended the Landau phase transition model to a ZB to RS transition by using a cosine function of the atom displacement as order parameter. The model shows that the position of the transition state does not depend on the coupling between the atom displacement and the strains of the lattice, which is the key point that the transition state is independent of the chemical components. [1] M. S. Miao and Walter R. L. Lambrecht, Phys. Rev. B 68, 092103 (2003). [2] M. S. Miao and Walter R. L. Lambrecht, Phys. Rev. Lett., accepted
18. The transition to the metallic state in low density hydrogen.
PubMed
McMinis, Jeremy; Morales, Miguel A; Ceperley, David M; Kim, Jeongnim
2015-11-21
Solid atomic hydrogen is one of the simplest systems to undergo a metal-insulator transition. Near the transition, the electronic degrees of freedom become strongly correlated and their description provides a difficult challenge for theoretical methods. As a result, the order and density of the phase transition are still subject to debate. In this work, we use diffusion quantum Monte Carlo to benchmark the transition between paramagnetic and anti-ferromagnetic body centered cubic atomic hydrogen in its ground state. We locate the density of the transition by computing the equation of state for these two phases and identify the phase transition order by computing the band gap near the phase transition. These benchmark results show that the phase transition is continuous and occurs at a Wigner-Seitz radius of rs = 2.27(3) a0. We compare our results to previously reported density functional theory, Hedin's GW approximation, and dynamical mean field theory results. PMID:26590549
19. Smooth transitions from the Schwarzschild vacuum to de Sitter space
SciTech Connect
Conboy, Steven; Lake, Kayll
2005-06-15
We provide an infinity of spacetimes which contain part of both the Schwarzschild vacuum and de Sitter space. The transition, which occurs below the Schwarzschild event horizon, involves only boundary surfaces (no surface layers). An explicit example is given in which the weak and strong energy conditions are satisfied everywhere (except in the de Sitter section) and the dominant energy condition is violated only in the vicinity of the boundary to the Schwarzschild section. The singularity is avoided by way of a change in topology in accord with a theorem due to Borde.
20. Frequency domain state-space system identification
NASA Technical Reports Server (NTRS)
Chen, Chung-Wen; Juang, Jer-Nan; Lee, Gordon
1992-01-01
An algorithm for identifying state-space models from frequency response data of linear systems is presented. A matrix-fraction description of the transfer function is employed to curve-fit the frequency response data, using the least-squares method. The parameters of the matrix-fraction representation are then used to construct the Markov parameters of the system. Finally, state-space models are obtained through the Eigensystem Realization Algorithm using Markov parameters. The main advantage of this approach is that the curve-fitting and the Markov parameter construction are linear problems which avoid the difficulties of nonlinear optimization of other approaches. Another advantage is that it avoids windowing distortions associated with other frequency domain methods.
1. Two-photon transitions to excited states in atomic hydrogen
SciTech Connect
Quattropani, A.; Bassani, F.; Carillo, S.
1982-06-01
Resonant two-photon transition rates from the ground state of atomic hydrogen to ns excited states have been computed as a function of photon frequencies in the length and velocity gauges in order to test the accuracy of the calculation and to discuss the rate of convergence over the intermediate states. The dramatic structure of the transition rates produced by intermediate-state resonances is exhibited. A two-photon transparency is found in correspondence to each resonance.
2. The Variable Transition State in Polar Additions to Pi Bonds
ERIC Educational Resources Information Center
Weiss, Hilton M.
2010-01-01
A vast majority of polar additions of Bronsted acids to alkynes involve a termolecular transition state. With strong acids, considerable positive charge is developed on carbon and Markovnikov addition predominates. In less acidic solutions, however, the reaction is much slower and the transition state more closely resembles the olefinic product.…
3. State-space formulations for flutter analysis
NASA Technical Reports Server (NTRS)
Weiss, S. J.; Tseng, K.; Morino, L.
1976-01-01
Various methods are presented and assessed for approximating the aerodynamic forces so that the State Space formulation and off-the-imaginary axis analysis are retained. The advantages of retaining these features are considerable, not only in simplifying the flutter analysis, but especially for more advanced applications such as optimal design of active control in which the flutter is merely a constraint to the optimization problem.
4. A flexible transition state searching method for atmospheric reaction systems
Lin, Xiao-Xiao; Liu, Yi-Rong; Huang, Teng; Chen, Jiao; Jiang, Shuai; Huang, Wei
2015-04-01
The precise and rapid exploration of transition states (TSs) is a major challenge when studying atmospheric reactions due to their complexity. In this work, a Monte Carlo Transition State Search Method (MCTSSM), which integrates Monte Carlo sampling technique with transition state optimization methods using an efficient computer script, has been developed for transition state searches. The efficiency and the potential application in atmospheric reactions of this method have been demonstrated by three types of test suits related to the reactions of atmospheric volatile organic compounds (VOCs): (1) OH addition, (2) OH hydrogen-abstraction, and (3) the other reactive group (e.g. Cl, O3, NO3), especially for the reaction of β-pinene-sCI (stabilized Criegee Intermediates) with water. It was shown that the application of this method with effective restricted parameters has greatly simplified the time-consuming and tedious manual search procedure for transition state (TS) of the bimolecular reaction systems.
5. A Flexible Transition State Searching Method for Atmospheric Reaction Systems
SciTech Connect
Lin, Xiao-Xiao; Liu, Yi-Rong; Huang, Teng; Chen, Jiao; Jiang, Shuai; Huang, Wei
2015-04-01
The precise and rapid exploration of transition states (TSs) is a major challenge when studying atmospheric reactions due to their complexity. In this work, a Monte Carlo Transition State Search Method (MCTSSM), which integrates Monte Carlo sampling technique with transition state optimization methods using an efficient computer script, has been developed for transition state searches. The efficiency and the potential application in atmospheric reactions of this method have been demonstrated by three types of test suits related to the reactions of atmospheric volatile organic compounds (VOCs): (1) OH addition, (2) OH hydrogen-abstraction, and (3) the other reactive group (e.g. Cl, O3, NO3), especially for the reaction of β-pinene-sCI (stabilized Criegee Intermediates) with water. It was shown that the application of this method with effective restricted parameters has greatly simplified the time-consuming and tedious manual search procedure for transition state (TS) of the bimolecular reaction systems.
6. Space Shuttle Boundary Layer Transition Flight Experiment Ground Testing Overview
NASA Technical Reports Server (NTRS)
Berger, Karen T.; Anderson, Brian P.; Campbell, Charles H.
2014-01-01
In support of the Boundary Layer Transition (BLT) Flight Experiment (FE) Project in which a manufactured protuberance tile was installed on the port wing of Space Shuttle Orbiter Discovery for STS-119, STS- 128, STS-131 and STS-133 as well as Space Shuttle Orbiter Endeavour for STS-134, a significant ground test campaign was completed. The primary goals of the test campaign were to provide ground test data to support the planning and safety certification efforts required to fly the flight experiment as well as validation for the collected flight data. These test included Arcjet testing of the tile protuberance, aerothermal testing to determine the boundary layer transition behavior and resultant surface heating and planar laser induced fluorescence (PLIF) testing in order to gain a better understanding of the flow field characteristics associated with the flight experiment. This paper provides an overview of the BLT FE Project ground testing. High-level overviews of the facilities, models, test techniques and data are presented, along with a summary of the insights gained from each test.
7. Modeling volatility using state space models.
PubMed
Timmer, J; Weigend, A S
1997-08-01
In time series problems, noise can be divided into two categories: dynamic noise which drives the process, and observational noise which is added in the measurement process, but does not influence future values of the system. In this framework, we show that empirical volatilities (the squared relative returns of prices) exhibit a significant amount of observational noise. To model and predict their time evolution adequately, we estimate state space models that explicitly include observational noise. We obtain relaxation times for shocks in the logarithm of volatility ranging from three weeks (for foreign exchange) to three to five months (for stock indices). In most cases, a two-dimensional hidden state is required to yield residuals that are consistent with white noise. We compare these results with ordinary autoregressive models (without a hidden state) and find that autoregressive models underestimate the relaxation times by about two orders of magnitude since they do not distinguish between observational and dynamic noise. This new interpretation of the dynamics of volatility in terms of relaxators in a state space model carries over to stochastic volatility models and to GARCH models, and is useful for several problems in finance, including risk management and the pricing of derivative securities. Data sets used: Olsen & Associates high frequency DEM/USD foreign exchange rates (8 years). Nikkei 225 index (40 years). Dow Jones Industrial Average (25 years). PMID:9730016
8. Markov chain evaluation of acute postoperative pain transition states.
PubMed
Tighe, Patrick J; Bzdega, Matthew; Fillingim, Roger B; Rashidi, Parisa; Aytug, Haldun
2016-03-01
Previous investigations on acute postoperative pain dynamicity have focused on daily pain assessments, and so were unable to examine intraday variations in acute pain intensity. We analyzed 476,108 postoperative acute pain intensity ratings, which were clinically documented on postoperative days 1 to 7 from 8346 surgical patients using Markov chain modeling to describe how patients are likely to transition from one pain state to another in a probabilistic fashion. The Markov chain was found to be irreducible and positive recurrent, with no absorbing states. Transition probabilities ranged from 0.0031, for the transition from state 10 to state 1, to 0.69 for the transition from state 0 to state 0. The greatest density of transitions was noted in the diagonal region of the transition matrix, suggesting that patients were generally most likely to transition to the same pain state as their current state. There were also slightly increased probability densities in transitioning to a state of asleep or 0 from the current state. An examination of the number of steps required to traverse from a particular first pain score to a target state suggested that overall, fewer steps were required to reach a state of 0 (range 6.1-8.8 steps) or asleep (range 9.1-11) than were required to reach a mild pain intensity state. Our results suggest that using Markov chains is a feasible method for describing probabilistic postoperative pain trajectories, pointing toward the possibility of using Markov decision processes to model sequential interactions between pain intensity ratings, and postoperative analgesic interventions. PMID:26588689
9. 40 CFR 70.4 - State program submittals and transition.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 16 2014-07-01 2014-07-01 false State program submittals and... PROGRAMS (CONTINUED) STATE OPERATING PERMIT PROGRAMS § 70.4 State program submittals and transition. (a... Administrator for approval a proposed part 70 program, under State law or under an interstate compact,...
10. 40 CFR 70.4 - State program submittals and transition.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 16 2012-07-01 2012-07-01 false State program submittals and... PROGRAMS (CONTINUED) STATE OPERATING PERMIT PROGRAMS § 70.4 State program submittals and transition. (a... Administrator for approval a proposed part 70 program, under State law or under an interstate compact,...
11. 40 CFR 70.4 - State program submittals and transition.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 16 2013-07-01 2013-07-01 false State program submittals and... PROGRAMS (CONTINUED) STATE OPERATING PERMIT PROGRAMS § 70.4 State program submittals and transition. (a... Administrator for approval a proposed part 70 program, under State law or under an interstate compact,...
12. The folding transition state theory in simple model systems
Niewieczerzał, Szymon; Cieplak, Marek
2008-06-01
We present the results of an exact analysis of several model free energy landscapes of a protein to clarify the notion of the transition state and the physical meaning of the phi values determined in protein engineering experiments. We argue that a proper search strategy for the transition state in more realistic models should involve identification of a common part of various methods. Two of the models considered involve explicit conformations instead of just points on the free energy axis. These models are minimalistic as they are endowed only with five or 36 states to enumerate folding paths and to identify the transition state easily. Even though they display much of the two-state behavior, the phi values are found not to correspond to the conformation of the transition state.
13. The State of Space Propulsion Research
NASA Technical Reports Server (NTRS)
Sackheim, R. L.; Cole, J. W.; Litchford, R. J.
2006-01-01
The current state of space propulsion research is assessed from both a historical perspective, spanning the decades since Apollo, and a forward-looking perspective, as defined by the enabling technologies required for a meaningful and sustainable human and robotic exploration program over the forthcoming decades. Previous research and technology investment approaches are examined and a course of action suggested for obtaining a more balanced portfolio of basic and applied research. The central recommendation is the establishment of a robust national Space Propulsion Research Initiative that would run parallel with systems development and include basic research activities. The basic framework and technical approach for this proposed initiative are defined and a potential implementation approach is recommended.
14. Transition State Structure of RNA Depurination by Saporin L3.
PubMed
Yuan, Hongling; Stratton, Christopher F; Schramm, Vern L
2016-05-20
Saporin L3 from the leaves of the common soapwort is a catalyst for hydrolytic depurination of adenine from RNA. Saporin L3 is a type 1 ribosome inactivating protein (RIP) composed only of a catalytic domain. Other RIPs have been used in immunotoxin cancer therapy, but off-target effects have limited their development. In the current study, we use transition state theory to understand the chemical mechanism and transition state structure of saporin L3. In favorable cases, transition state structures guide the design of transition state analogues as inhibitors. Kinetic isotope effects (KIEs) were determined for an A14C mutant of saporin L3. To permit KIE measurements, small stem-loop RNAs that contain an AGGG tetraloop structure were enzymatically synthesized with the single adenylate bearing specific isotopic substitutions. KIEs were measured and corrected for forward commitment to obtain intrinsic values. A model of the transition state structure for depurination of stem-loop RNA (5'-GGGAGGGCCC-3') by saporin L3 was determined by matching KIE values predicted via quantum chemical calculations to a family of intrinsic KIEs. This model indicates saporin L3 displays a late transition state with the N-ribosidic bond to the adenine nearly cleaved, and the attacking water nucleophile weakly bonded to the ribosyl anomeric carbon. The transition state retains partial ribocation character, a feature common to most N-ribosyl transferases. However, the transition state geometry for saporin L3 is distinct from ricin A-chain, the only other RIP whose transition state is known. PMID:26886255
15. Momentum space imaging of the FFLO state
Akbari, Alireza; Thalmeier, Peter
2016-06-01
In a magnetic field superconductors (SC) with small orbital effect exhibit the Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) phase above the Pauli limiting field. It is characterized by Cooper pairs with finite center of mass momentum and is stabilized by the gain in Zeeman energy of depaired electrons in the imbalanced Fermi gas. The ground state is a coherent superposition of paired and depaired states. This concept, although central to the FFLO state lacks a direct experimental confirmation. We propose that STM quasiparticle interference (QPI) can give a direct momentum space image of the depaired states in the FFLO wave function. For a proof of principle we investigate a 2D single orbital tight binding model with a SC s-wave order parameter. Using the equilibrium values of pair momentum and SC gap we calculate the spectral function of quasiparticles and associated QPI spectrum as function of magnetic field. We show that the characteristic depaired Fermi surface parts appear as a fingerprint in the QPI spectrum of the FFLO phase and we demonstrate its evolution with field strength. Its observation in STM experiments would constitute a direct proof for FFLO ground state wave function.
16. Morse bifurcations of transition states in bimolecular reactions
MacKay, R. S.; Strub, D. C.
2015-12-01
The transition states and dividing surfaces used to find rate constants for bimolecular reactions are shown to undergo Morse bifurcations, in which they change diffeomorphism class, and to exist for a large range of energies, not just immediately above the critical energy for first connection between reactants and products. Specifically, we consider capture between two molecules and the associated transition states for the case of non-zero angular momentum and general attitudes. The capture between an atom and a diatom, and then a general molecule are presented, providing concrete examples of Morse bifurcations of transition states and dividing surfaces.
17. Transition voltages of vacuum-spaced and molecular junctions with Ag and Pt electrodes
SciTech Connect
Wu, Kunlin; Bai, Meilin; Hou, Shimin; Sanvito, Stefano
2014-07-07
The transition voltage of vacuum-spaced and molecular junctions constructed with Ag and Pt electrodes is investigated by non-equilibrium Green's function formalism combined with density functional theory. Our calculations show that, similarly to the case of Au-vacuum-Au previously studied, the transition voltages of Ag and Pt metal-vacuum-metal junctions with atomic protrusions on the electrode surface are determined by the local density of states of the p-type atomic orbitals of the protrusion. Since the energy position of the Pt 6p atomic orbitals is higher than that of the 5p/6p of Ag and Au, the transition voltage of Pt-vacuum-Pt junctions is larger than that of both Ag-vacuum-Ag and Au-vacuum-Au junctions. When one moves to analyzing asymmetric molecular junctions constructed with biphenyl thiol as central molecule, then the transition voltage is found to depend on the specific bonding site for the sulfur atom in the thiol group. In particular agreement with experiments, where the largest transition voltage is found for Ag and the smallest for Pt, is obtained when one assumes S binding at the hollow-bridge site on the Ag/Au(111) surface and at the adatom site on the Pt(111) one. This demonstrates the critical role played by the linker-electrode binding geometry in determining the transition voltage of devices made of conjugated thiol molecules.
18. Theory of Interface States at Silicon / Transition - - Silicide Interfaces.
Lim, Hunhwa
The Si/NiSi(,2)(111) interface is of both fundamental and techno- logical interest: From the fundamental point of view, it is the best characterized of all semiconductor/metal interfaces, with two well-determined geometries (A and B) involving nearly perfect bonding. (This is because Si and NiSi(,2) have nearly the same lattice spacing.) Consequently, a theoretical treatment of this system makes sense--as it would not for messier systems--and one can have some confidence that the theoretical predictions are relevant to experimental observa- tions. From the technological point of view, Si/NiSi(,2) is representative of the class of semiconductor/metal interfaces that are currently of greatest interest in regard to electronic devices--Si/transition -metal-silicide interfaces. The calculations of this dissertation are for the intrinsic interface states of Si/NiSi(,2)-A geometry. These calculations also provide a foundation for later studies of defects at this interface, and for studies of other related systems, such as CoSi(,2). The calculations employ empirical tight-binding Hamiltonians for both Si and NiSi(,2) (with the parameters fitted to prior calculations of the bulk band structures, which appear to be in agreement with the available experimental data on bulk Si and NiSi(,2)). They also employ Green's function techniques--in particular, the subspace Hamiltonian technique. Our principal results are the following: (1) Interface state disper- sion curves are predicted along the symmetry lines (')(GAMMA)(')M, (')M(')K and (')K(')(GAMMA) of the surface Brillouin zone. (2) A prominent band of interface states is found which disperses downward from an energy within the Si band gap to an energy below the Si valence band edge E(,(upsilon)) as the planar wavevector (')k increases from (')(GAMMA) ((')k = 0) to (')M or (')K (symmetry points at boundary of the surface Brillouin zone). This band of inter- face states should be observable. It produces a peak in the surface
19. The photon-plasmon transitions and diagnostics of the space plasma turbulence
Glushkov, Alexander; Glushkov, Alexander; Khetselius, Olga
We present a new approach to treating the space plasma turbulence, based on using to make diagnostic data regarding the photon-plasmon transitions. The theoretical definition of characteristics for these transitions is caried out within consistent theoretical approach, based on the Gell-Mann and Low formalism (energy approach in QED theory).We apply it to calculation of such transitions (Ps) with emission of photon and Langmuir quanta. It is well known that the hfs states of positronium Ps Ps differ in spin S, life time t and mode of annihilation. As a rule, probabilities of the cascade radiation transitions are more than the annihilation probability. The ortho-Ps atom has a metastable state 23s1 and probability of two-photon radiation transition from this state into 13s1 state (1.8•10(-3) 1/s) is significantly less than probability of the three-photon annihilation directly from 23s1level 8.9•10(5) s(-1), i.e. it is usually supposed that the ortho-Ps annihilates from 23s1state. Another situation may take place in plasma, where it is arisen the competition process of destruction of the metastable level - the photonplasmon transition 23s1-13s1with emission of photon and Langmuir quanta. In this paper we carried out the calculation of the probability of the Ps photon-plasmon transition and propose tu use it for diagnostics of the space plasma (dusty one etc.).Standard S-matrix calculation with using an expression for tensor of dielectric permeability of the isotropic space plasma and dispersion relationships for transverse and Langmuir waves [3] allows getting the corresponding probability P(ph-pl). Numerical value of P(ph-pl) is 5.2•10(6)•UL(s-1), where UL is density of the Langmuir waves energy. Our value is correlated with estimate, available in literature [3]: P(phpl)= 6•10(6)•UL (s-1). Comparison of the obtained probability with the life time t(3) allows getting the condition of predominance of the photon-plasmon transition over three
20. 45 CFR 150.221 - Transition to State enforcement.
Code of Federal Regulations, 2011 CFR
2011-10-01
... Determining Whether States Are Failing To Substantially Enforce HIPAA Requirements § 150.221 Transition to... enacted and implemented legislation to enforce HIPAA requirements and also determines that it...
1. 45 CFR 150.221 - Transition to State enforcement.
Code of Federal Regulations, 2010 CFR
2010-10-01
... Determining Whether States Are Failing To Substantially Enforce HIPAA Requirements § 150.221 Transition to... enacted and implemented legislation to enforce HIPAA requirements and also determines that it...
2. 45 CFR 150.221 - Transition to State enforcement.
Code of Federal Regulations, 2012 CFR
2012-10-01
... Determining Whether States Are Failing To Substantially Enforce HIPAA Requirements § 150.221 Transition to... enacted and implemented legislation to enforce HIPAA requirements and also determines that it...
3. Grassland-shrubland state transitions in arid lands: Competition matters
Technology Transfer Automated Retrieval System (TEKTRAN)
Background/Question/Methods: State transition from grassland to shrubland is synonymous with desertification in many dryland systems. The classic desertification model emphasizes abiotic feedbacks that modify the physical environment in ways that promote shrub proliferation and impede grass survival...
4. Transition state theory and the dynamics of hard disks
Barnett-Jones, M.; Dickinson, P. A.; Godfrey, M. J.; Grundy, T.; Moore, M. A.
2013-11-01
The dynamics of two- and five-disk systems confined in a square has been studied using molecular dynamics simulations and compared with the predictions of transition state theory. We determine the partition functions Z and Z‡ of transition state theory using a procedure first used by Salsburg and Wood for the pressure. Our simulations show this procedure and transition state theory are in excellent agreement with the simulations. A generalization of the transition state theory to the case of a large number of disks N is made and shown to be in full agreement with simulations of disks moving in a narrow channel. The same procedure for hard spheres in three dimensions leads to the Vogel-Fulcher-Tammann formula for their alpha relaxation time.
5. Interplanetary Transit Simulations Using the International Space Station
NASA Technical Reports Server (NTRS)
Charles, J. B.; Arya, Maneesh
2010-01-01
It has been suggested that the International Space Station (ISS) be utilized to simulate the transit portion of long-duration missions to Mars and near-Earth asteroids (NEA). The ISS offers a unique environment for such simulations, providing researchers with a high-fidelity platform to study, enhance, and validate technologies and countermeasures for these long-duration missions. From a space life sciences perspective, two major categories of human research activities have been identified that will harness the various capabilities of the ISS during the proposed simulations. The first category includes studies that require the use of the ISS, typically because of the need for prolonged weightlessness. The ISS is currently the only available platform capable of providing researchers with access to a weightless environment over an extended duration. In addition, the ISS offers high fidelity for other fundamental space environmental factors, such as isolation, distance, and accessibility. The second category includes studies that do not require use of the ISS in the strictest sense, but can exploit its use to maximize their scientific return more efficiently and productively than in ground-based simulations. In addition to conducting Mars and NEA simulations on the ISS, increasing the current increment duration on the ISS from 6 months to a longer duration will provide opportunities for enhanced and focused research relevant to long-duration Mars and NEA missions. Although it is currently believed that increasing the ISS crew increment duration to 9 or even 12 months will pose little additional risk to crewmembers, additional medical monitoring capabilities may be required beyond those currently used for the ISS operations. The use of the ISS to simulate aspects of Mars and NEA missions seems practical, and it is recommended that planning begin soon, in close consultation with all international partners.
6. Enhancing pairwise state-transition weights: A new weighting scheme in simulated tempering that can minimize transition time between a pair of conformational states.
PubMed
Qiao, Qin; Zhang, Hou-Dao; Huang, Xuhui
2016-04-21
Simulated tempering (ST) is a widely used enhancing sampling method for Molecular Dynamics simulations. As one expanded ensemble method, ST is a combination of canonical ensembles at different temperatures and the acceptance probability of cross-temperature transitions is determined by both the temperature difference and the weights of each temperature. One popular way to obtain the weights is to adopt the free energy of each canonical ensemble, which achieves uniform sampling among temperature space. However, this uniform distribution in temperature space may not be optimal since high temperatures do not always speed up the conformational transitions of interest, as anti-Arrhenius kinetics are prevalent in protein and RNA folding. Here, we propose a new method: Enhancing Pairwise State-transition Weights (EPSW), to obtain the optimal weights by minimizing the round-trip time for transitions among different metastable states at the temperature of interest in ST. The novelty of the EPSW algorithm lies in explicitly considering the kinetics of conformation transitions when optimizing the weights of different temperatures. We further demonstrate the power of EPSW in three different systems: a simple two-temperature model, a two-dimensional model for protein folding with anti-Arrhenius kinetics, and the alanine dipeptide. The results from these three systems showed that the new algorithm can substantially accelerate the transitions between conformational states of interest in the ST expanded ensemble and further facilitate the convergence of thermodynamics compared to the widely used free energy weights. We anticipate that this algorithm is particularly useful for studying functional conformational changes of biological systems where the initial and final states are often known from structural biology experiments. PMID:27389209
7. Enhancing pairwise state-transition weights: A new weighting scheme in simulated tempering that can minimize transition time between a pair of conformational states
Qiao, Qin; Zhang, Hou-Dao; Huang, Xuhui
2016-04-01
Simulated tempering (ST) is a widely used enhancing sampling method for Molecular Dynamics simulations. As one expanded ensemble method, ST is a combination of canonical ensembles at different temperatures and the acceptance probability of cross-temperature transitions is determined by both the temperature difference and the weights of each temperature. One popular way to obtain the weights is to adopt the free energy of each canonical ensemble, which achieves uniform sampling among temperature space. However, this uniform distribution in temperature space may not be optimal since high temperatures do not always speed up the conformational transitions of interest, as anti-Arrhenius kinetics are prevalent in protein and RNA folding. Here, we propose a new method: Enhancing Pairwise State-transition Weights (EPSW), to obtain the optimal weights by minimizing the round-trip time for transitions among different metastable states at the temperature of interest in ST. The novelty of the EPSW algorithm lies in explicitly considering the kinetics of conformation transitions when optimizing the weights of different temperatures. We further demonstrate the power of EPSW in three different systems: a simple two-temperature model, a two-dimensional model for protein folding with anti-Arrhenius kinetics, and the alanine dipeptide. The results from these three systems showed that the new algorithm can substantially accelerate the transitions between conformational states of interest in the ST expanded ensemble and further facilitate the convergence of thermodynamics compared to the widely used free energy weights. We anticipate that this algorithm is particularly useful for studying functional conformational changes of biological systems where the initial and final states are often known from structural biology experiments.
8. Edge States in Transitional Pipe Flow
Schneider, Tobias M.; Eckhardt, Bruno
2006-11-01
We study the boundary of the laminar region near the onset of turbulence. Approaching the boundary from the laminar side, the lifetime of perturbations increases, diverges when the boundary is reached, and varies chaotically for larger amplitudes. In the chaotic region, lifetimes vary sensitively with amplitude, consistent with the strange saddle picture of the turbulence proposed earlier. The trajectory on the edge between the laminar and chaotic regions is asymptotic to a single well defined state, essentially independent of the type of perturbation. The edge then becomes the stable manifold of this structure. In the case of a model shear flow, the edge states are simple or period doubled or chaotic trajectories. In the case of pipe flow the edge state seems to remain close to a state with simple vortical structure. Edge of Chaos in a Parallel Shear Flow, Joseph D. Skufca, James A. Yorke, and Bruno Eckhardt, Phys. Rev. Lett. 96, 174101 (2006)
9. Thermal effects and space-charge limited transition in crossed-field devices
SciTech Connect
Marini, Samuel; Rizzato, Felipe B.; Pakter, Renato
2014-08-15
A fully kinetic model for the electron flow in a crossed field device is derived and used to determine the system stationary states. It is found that for low injection temperatures, there is a simultaneous presence of distinct stationary solutions and an abrupt transition between accelerating and space-charge limited regimes. On the other hand, for high injection temperatures, there is only a single stationary solution branch and the change between the regimes becomes continuous. For intermediate temperatures, it is then identified a critical point that separates the abrupt and continuous behaviors. It is also investigated how intrinsic space-charge oscillations may drive stationary states unstable in certain parameter regimes. The results are verified with N-particle self-consistent simulations.
10. Mental health work with Gulf War evacuees: the use of a transitional therapeutic space.
PubMed
Benyakar, M; Kretsch, R; Baruch, E
1994-01-01
This paper describes the intervention of a mental health team formed during the Persian Gulf War to provide assistance to people evacuated from their homes after they were seriously damaged or destroyed by Iraqi Scud missiles. The intervention was based on the view that a crisis upsets the person's emotional equilibrium, resulting in a new and alien emotional state, which is frightening to the person involved by virtue of its strangeness. The disturbance may result in the development of a frozen, rigid unadaptive internal state, i.e. trauma. The mental health team used the interaction between external and internal realities, within a transitional space which enabled the development of a potential space. PMID:7928296
11. State Machine Modeling of the Space Launch System Solid Rocket Boosters
NASA Technical Reports Server (NTRS)
Harris, Joshua A.; Patterson-Hine, Ann
2013-01-01
The Space Launch System is a Shuttle-derived heavy-lift vehicle currently in development to serve as NASA's premiere launch vehicle for space exploration. The Space Launch System is a multistage rocket with two Solid Rocket Boosters and multiple payloads, including the Multi-Purpose Crew Vehicle. Planned Space Launch System destinations include near-Earth asteroids, the Moon, Mars, and Lagrange points. The Space Launch System is a complex system with many subsystems, requiring considerable systems engineering and integration. To this end, state machine analysis offers a method to support engineering and operational e orts, identify and avert undesirable or potentially hazardous system states, and evaluate system requirements. Finite State Machines model a system as a finite number of states, with transitions between states controlled by state-based and event-based logic. State machines are a useful tool for understanding complex system behaviors and evaluating "what-if" scenarios. This work contributes to a state machine model of the Space Launch System developed at NASA Ames Research Center. The Space Launch System Solid Rocket Booster avionics and ignition subsystems are modeled using MATLAB/Stateflow software. This model is integrated into a larger model of Space Launch System avionics used for verification and validation of Space Launch System operating procedures and design requirements. This includes testing both nominal and o -nominal system states and command sequences.
12. Polymorphic phase transitions in systems evolving in a two-dimensional discrete space.
PubMed
1999-08-01
Polymorphic phase transitions in systems evolving in a two-dimensional discrete space have been studied. The driving force of the transitions appears to be a difference between two main energetic contributions: one, related to the thermal activation of the process, and another, being of quantum nature. The former (high temperature limit) is naturally assigned to the expansion (melting) part of the transition, while the latter (low temperature limit) has much in common with the contraction (solidification) part. Between the two main physical states distinguished, there exists a certain state, corresponding to a discontinuity point (pole) in the morphological phase diagram, represented by the well-known Bose-Einstein (Planck) formula, in which the system blows up. This point is related to an expected situation in which the contour of the object under investigation stands for the Brownian or purely diffusional path, with the fractal dimension dw=2, and the situation can be interpreted as some emergence of an intermediate "tetratic" phase. This, in turn, recalls a certain analogy to the equilibrium (order-disorder) phase transition of Kosterlitz-Thouless type, characteristic of, e.g., rough vs rigid interfaces in a two-dimensional space, with some disappearance of interface correlation length at dw=2. Otherwise, the contours of the objects are equivalent to fractional Brownian paths either in superlinear or "turbulent" (dw<2; the expansion case), or sublinear, viz., anomalously slow (dw>2; the contraction case) regimes, respectively. It is hoped that the description offered will serve to reflect properly the main subtleties of the dynamics of the polymorphic transitions in complex "soft-matter" systems, like formation of lipid mesomorphs or diffusional patterns, with nonzero line tension effect. PMID:11969883
13. Performance and state-space analyses of systems using Petri nets
NASA Technical Reports Server (NTRS)
Watson, James Francis, III
1992-01-01
The goal of any modeling methodology is to develop a mathematical description of a system that is accurate in its representation and also permits analysis of structural and/or performance properties. Inherently, trade-offs exist between the level detail in the model and the ease with which analysis can be performed. Petri nets (PN's), a highly graphical modeling methodology for Discrete Event Dynamic Systems, permit representation of shared resources, finite capacities, conflict, synchronization, concurrency, and timing between state changes. By restricting the state transition time delays to the family of exponential density functions, Markov chain analysis of performance problems is possible. One major drawback of PN's is the tendency for the state-space to grow rapidly (exponential complexity) compared to increases in the PN constructs. It is the state space, or the Markov chain obtained from it, that is needed in the solution of many problems. The theory of state-space size estimation for PN's is introduced. The problem of state-space size estimation is defined, its complexities are examined, and estimation algorithms are developed. Both top-down and bottom-up approaches are pursued, and the advantages and disadvantages of each are described. Additionally, the author's research in non-exponential transition modeling for PN's is discussed. An algorithm for approximating non-exponential transitions is developed. Since only basic PN constructs are used in the approximation, theory already developed for PN's remains applicable. Comparison to results from entropy theory show the transition performance is close to the theoretic optimum. Inclusion of non-exponential transition approximations improves performance results at the expense of increased state-space size. The state-space size estimation theory provides insight and algorithms for evaluating this trade-off.
14. Precritical State Transition Dynamics in the Attractor Landscape of a Molecular Interaction Network Underlying Colorectal Tumorigenesis
PubMed Central
Cho, Kwang-Hyun
2015-01-01
From the perspective of systems science, tumorigenesis can be hypothesized as a critical transition (an abrupt shift from one state to another) between proliferative and apoptotic attractors on the state space of a molecular interaction network, for which an attractor is defined as a stable state to which all initial states ultimately converge, and the region of convergence is called the basin of attraction. Before the critical transition, a cellular state might transit between the basin of attraction for an apoptotic attractor and that for a proliferative attractor due to the noise induced by the inherent stochasticity in molecular interactions. Such a flickering state transition (state transition between the basins of attraction for alternative attractors from the impact of noise) would become more frequent as the cellular state approaches near the boundary of the basin of attraction, which can increase the variation in the estimate of the respective basin size. To investigate this for colorectal tumorigenesis, we have constructed a stochastic Boolean network model of the molecular interaction network that contains an important set of proteins known to be involved in cancer. In particular, we considered 100 representative sequences of 20 gene mutations that drive colorectal tumorigenesis. We investigated the appearance of cancerous cells by examining the basin size of apoptotic, quiescent, and proliferative attractors along with the sequential accumulation of gene mutations during colorectal tumorigenesis. We introduced a measure to detect the flickering state transition as the variation in the estimate of the basin sizes for three-phenotype attractors from the impact of noise. Interestingly, we found that this measure abruptly increases before a cell becomes cancerous during colorectal tumorigenesis in most of the gene mutation sequences under a certain level of stochastic noise. This suggests that a frequent flickering state transition can be a precritical
15. Solid state neutron dosimeter for space applications
SciTech Connect
Nagarkar, V.; Entine, G.; Stoppel, P.; Cirignano, L. ); Swinehart, P. )
1992-08-01
One of the most important contributions to the radiation exposure of astronauts engaged in space flight is the significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Under NASA sponsorship, the authors are developing a solid state neutron sensor capable of being incorporated into a very compact, flight instrument to provide high quality real time measurement of this important radiation flux. The dosimeter uses a special, high neutron sensitivity, PIN diode that is insensitive t the other forms of ionizing radiation. The dosimeter will have the ability to measure and record neutron dose over a range of 50 microgray to tens of milligrays (5 millirads to several rads) over a flight of up to 30 days. the performance characteristics of the PIN diode with a detailed description of the overall dosimeter is presented. in this paper.
16. Space and time renormalization in phase transition dynamics
DOE PAGESBeta
Francuz, Anna; Dziarmaga, Jacek; Gardas, Bartłomiej; Zurek, Wojciech H.
2016-02-18
Here, when a system is driven across a quantum critical point at a constant rate, its evolution must become nonadiabatic as the relaxation time τ diverges at the critical point. According to the Kibble-Zurek mechanism (KZM), the emerging post-transition excited state is characterized by a finite correlation length ξˆ set at the time tˆ=τˆ when the critical slowing down makes it impossible for the system to relax to the equilibrium defined by changing parameters. This observation naturally suggests a dynamical scaling similar to renormalization familiar from the equilibrium critical phenomena. We provide evidence for such KZM-inspired spatiotemporal scaling by investigatingmore » an exact solution of the transverse field quantum Ising chain in the thermodynamic limit.« less
17. Presence of state transitions in the cryptophyte alga Guillardia theta
PubMed Central
Cheregi, Otilia; Kotabová, Eva; Prášil, Ondřej; Schröder, Wolfgang P.; Kaňa, Radek; Funk, Christiane
2015-01-01
Plants and algae have developed various regulatory mechanisms for optimal delivery of excitation energy to the photosystems even during fluctuating light conditions; these include state transitions as well as non-photochemical quenching. The former process maintains the balance by redistributing antennae excitation between the photosystems, meanwhile the latter by dissipating excessive excitation inside the antennae. In the present study, these mechanisms have been analysed in the cryptophyte alga Guillardia theta. Photoprotective non-photochemical quenching was observed in cultures only after they had entered the stationary growth phase. These cells displayed a diminished overall photosynthetic efficiency, measured as CO2 assimilation rate and electron transport rate. However, in the logarithmic growth phase G. theta cells redistributed excitation energy via a mechanism similar to state transitions. These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective. It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively. G. theta therefore represents a chromalveolate algae able to perform state transitions. PMID:26254328
18. Presence of state transitions in the cryptophyte alga Guillardia theta.
PubMed
Cheregi, Otilia; Kotabová, Eva; Prášil, Ondřej; Schröder, Wolfgang P; Kaňa, Radek; Funk, Christiane
2015-10-01
Plants and algae have developed various regulatory mechanisms for optimal delivery of excitation energy to the photosystems even during fluctuating light conditions; these include state transitions as well as non-photochemical quenching. The former process maintains the balance by redistributing antennae excitation between the photosystems, meanwhile the latter by dissipating excessive excitation inside the antennae. In the present study, these mechanisms have been analysed in the cryptophyte alga Guillardia theta. Photoprotective non-photochemical quenching was observed in cultures only after they had entered the stationary growth phase. These cells displayed a diminished overall photosynthetic efficiency, measured as CO2 assimilation rate and electron transport rate. However, in the logarithmic growth phase G. theta cells redistributed excitation energy via a mechanism similar to state transitions. These state transitions were triggered by blue light absorbed by the membrane integrated chlorophyll a/c antennae, and green light absorbed by the lumenal biliproteins was ineffective. It is proposed that state transitions in G. theta are induced by small re-arrangements of the intrinsic antennae proteins, resulting in their coupling/uncoupling to the photosystems in state 1 or state 2, respectively. G. theta therefore represents a chromalveolate algae able to perform state transitions. PMID:26254328
19. The transition to the metallic state in low density hydrogen
SciTech Connect
McMinis, Jeremy; Morales, Miguel A.; Ceperley, David M.; Kim, Jeongnim
2015-11-21
Solid atomic hydrogen is one of the simplest systems to undergo a metal-insulator transition. Near the transition, the electronic degrees of freedom become strongly correlated and their description provides a difficult challenge for theoretical methods. As a result, the order and density of the phase transition are still subject to debate. In this work, we use diffusion quantum Monte Carlo to benchmark the transition between paramagnetic and anti-ferromagnetic body centered cubic atomic hydrogen in its ground state. We locate the density of the transition by computing the equation of state for these two phases and identify the phase transition order by computing the band gap near the phase transition. These benchmark results show that the phase transition is continuous and occurs at a Wigner-Seitz radius of r{sub s} = 2.27(3) a{sub 0}. We compare our results to previously reported density functional theory, Hedin’s GW approximation, and dynamical mean field theory results.
20. The transition to the metallic state in low density hydrogen
SciTech Connect
McMinis, Jeremy; Morales, Miguel A.; Ceperley, David M.; Kim, Jeongnim
2015-11-18
Solid atomic hydrogen is one of the simplest systems to undergo a metal-insulator transition. Near the transition, the electronic degrees of freedom become strongly correlated and their description provides a difficult challenge for theoretical methods. As a result, the order and density of the phase transition are still subject to debate. In this work we use diffusion quantum Monte Carlo to benchmark the transition between the paramagnetic and anti-ferromagnetic phases of ground state body centered cubic atomic hydrogen. We locate the density of the transition by computing the equation of state for these two phases and identify the phase transition order by computing the band gap near the phase transition. These benchmark results show that the phase transition is continuous and occurs at a Wigner-Seitz radius of rs = 2.27(3)a0. As a result, we compare our results to previously reported density functional theory, Hedin s GW approximation, and dynamical mean field theory results.
1. United States/Russia Space Cooperation Documentary
NASA Technical Reports Server (NTRS)
1993-01-01
This video documents the initiative to develop a multinational, permanent space research laboratory. Historical background on the U.S. and Soviet manned space flight program as well as joint efforts such as the Apollo-Soyuz link up is shown. The current initiative will begin with collaborative missions involving NASA's space shuttle and Russia's Mir space station, and culminate in a permanently manned space station involving the U.S., Russia, Japan, Canada, and ESA. Shown are computer simulations of the proposed space station. Commentary is provided by the NASA administrator, former astronauts, cosmonauts, and Russian and American space experts.
2. Transition State Analysis of Thymidine Hydrolysis by Human Thymidine Phosphorylase*
PubMed Central
Schwartz, Phillip A.; Vetticatt, Mathew; Schramm, Vern L.
2010-01-01
Human thymidine phosphorylase (hTP) is responsible for thymidine (dT) homeostasis and its action promotes angiogenesis. In the absence of phosphate, hTP catalyzes a slow hydrolytic depyrimidination of dT yielding thymine and 2-deoxyribose (dRib). Its transition state was characterized using multiple kinetic isotope effect (KIE) measurements. Isotopically enriched thymidines were synthesized enzymatically from glucose or (deoxy)ribose and intrinsic KIEs were used to interpret the transition state structure. KIEs from [1′-14C]-, [1-15N]-, [1′-3H]-, [2′R-3H]-, [2′S-3H]-, [4′-3H]-, [5′-3H]dTs provided values of 1.033 ± 0.002, 1.004 ± 0.002, 1.325 ± 0.003, 1.101 ± 0.004, 1.087 ± 0.005, 1.040 ± 0.003, and 1.033 ± 0.003, respectively. Transition state analysis revealed a stepwise mechanism with a 2-deoxyribocation formed early and a higher energetic barrier for nucleophilic attack of a water molecule on the high energy intermediate. An equilibrium exists between the deoxyribocation and reactants prior to the irreversible nucleophilic attack by water. The results establish activation of the thymine leaving group without requirement for phosphate. A transition state constrained to match the intrinsic KIEs was found using density functional theory. An active site histidine (His116) is implicated as the catalytic base for activation of the water nucleophile at the rate-limiting transition state. The distance between the water nucleophile and the anomeric carbon (rC-O) is predicted to be 2.3 Å at the transition state. The transition state model predicts that deoxyribose adopts a mild 3′-endo confirmation during nucleophilic capture. These results differ from the concerted bimolecular mechanism reported for the arsenolytic reaction PMID:20804144
3. Exploring the Conformational Transitions of Biomolecular Systems Using a Simple Two-State Anisotropic Network Model
PubMed Central
Jo, Sunhwan; Bahar, Ivet; Roux, Benoît
2014-01-01
Biomolecular conformational transitions are essential to biological functions. Most experimental methods report on the long-lived functional states of biomolecules, but information about the transition pathways between these stable states is generally scarce. Such transitions involve short-lived conformational states that are difficult to detect experimentally. For this reason, computational methods are needed to produce plausible hypothetical transition pathways that can then be probed experimentally. Here we propose a simple and computationally efficient method, called ANMPathway, for constructing a physically reasonable pathway between two endpoints of a conformational transition. We adopt a coarse-grained representation of the protein and construct a two-state potential by combining two elastic network models (ENMs) representative of the experimental structures resolved for the endpoints. The two-state potential has a cusp hypersurface in the configuration space where the energies from both the ENMs are equal. We first search for the minimum energy structure on the cusp hypersurface and then treat it as the transition state. The continuous pathway is subsequently constructed by following the steepest descent energy minimization trajectories starting from the transition state on each side of the cusp hypersurface. Application to several systems of broad biological interest such as adenylate kinase, ATP-driven calcium pump SERCA, leucine transporter and glutamate transporter shows that ANMPathway yields results in good agreement with those from other similar methods and with data obtained from all-atom molecular dynamics simulations, in support of the utility of this simple and efficient approach. Notably the method provides experimentally testable predictions, including the formation of non-native contacts during the transition which we were able to detect in two of the systems we studied. An open-access web server has been created to deliver ANMPathway results
4. A Markovian state-space framework for integrating flexibility into space system design decisions
Lafleur, Jarret M.
The past decades have seen the state of the art in aerospace system design progress from a scope of simple optimization to one including robustness, with the objective of permitting a single system to perform well even in off-nominal future environments. Integrating flexibility, or the capability to easily modify a system after it has been fielded in response to changing environments, into system design represents a further step forward. One challenge in accomplishing this rests in that the decision-maker must consider not only the present system design decision, but also sequential future design and operation decisions. Despite extensive interest in the topic, the state of the art in designing flexibility into aerospace systems, and particularly space systems, tends to be limited to analyses that are qualitative, deterministic, single-objective, and/or limited to consider a single future time period. To address these gaps, this thesis develops a stochastic, multi-objective, and multi-period framework for integrating flexibility into space system design decisions. Central to the framework are five steps. First, system configuration options are identified and costs of switching from one configuration to another are compiled into a cost transition matrix. Second, probabilities that demand on the system will transition from one mission to another are compiled into a mission demand Markov chain. Third, one performance matrix for each design objective is populated to describe how well the identified system configurations perform in each of the identified mission demand environments. The fourth step employs multi-period decision analysis techniques, including Markov decision processes from the field of operations research, to find efficient paths and policies a decision-maker may follow. The final step examines the implications of these paths and policies for the primary goal of informing initial system selection. Overall, this thesis unifies state-centric concepts of
5. Kinetic transitions in diffusion-reaction space. II. Geometrical effects
Kozak, John J.
1999-02-01
We extend the stochastic master equation approach described earlier [J. J. Kozak and R. Davidson, J. Chem. Phys. 101, 6101 (1994)] to examine the influence on reaction efficiency of multipolar correlations between a fixed target molecule and a diffusing coreactant, the latter constrained to move on the surface of a host medium (e.g., a colloidal catalyst or molecular organizate) modeled as a Cartesian shell [Euler characteristic, χ=2]. Our most comprehensive results are for processes involving ion pairs, and we find that there exists a transition between two qualitatively different types of behavior in diffusion-reaction space, viz., a regime where the coreactant's motion is totally correlated with respect to the target ion, and a regime where the coreactant's motion is effectively uncorrelated. This behavior emerges both in the situation where correlations between the ion pair are strictly confined to the surface of the host medium or where correlations can be propagated through the host medium. The effects of system size are also examined and comparisons with diffusion-reaction processes taking place on surfaces characterized by Euler characteristic χ=0 are made. In all cases studied, the most dramatic effects on the reaction efficiency are uncovered in the regime where the Onsager (thermalization) length is comparable to the mean displacement of the coreactant, a conclusion consistent with results reported in earlier work.
6. Strain glass state as the boundary of two phase transitions.
PubMed
Zhou, Zhijian; Cui, Jian; Ren, Xiaobing
2015-01-01
A strain glass state was found to be located between B2-B19' (cubic to monoclinic) phase transition and B2-R (cubic to rhombohedral) phase transition in Ti49Ni51 alloys after aging process. After a short time aging, strong strain glass transition was observed, because the size of the precipitates is small, which means the strain field induced by the precipitates is isotropic and point-defect-like, and the distribution of the precipitates is random. After a long time aging, the average size of the precipitates increases. The strong strain field induced by the precipitates around them forces the symmetry of the matrix materials to conform to the symmetry of the crystalline structure of the precipitates, which results in the new phase transition. The experiment shows that there exists no well-defined boundary in the evolution from the strain glass transition to the new phase transition. Due to its generality, this glass mediated phase transition divergence scheme can be applied to other proper material systems to induce a more important new phase transition path, which can be useful in the field of phase transition engineering. PMID:26307500
7. Strain glass state as the boundary of two phase transitions
Zhou, Zhijian; Cui, Jian; Ren, Xiaobing
2015-08-01
A strain glass state was found to be located between B2-B19’ (cubic to monoclinic) phase transition and B2-R (cubic to rhombohedral) phase transition in Ti49Ni51 alloys after aging process. After a short time aging, strong strain glass transition was observed, because the size of the precipitates is small, which means the strain field induced by the precipitates is isotropic and point-defect-like, and the distribution of the precipitates is random. After a long time aging, the average size of the precipitates increases. The strong strain field induced by the precipitates around them forces the symmetry of the matrix materials to conform to the symmetry of the crystalline structure of the precipitates, which results in the new phase transition. The experiment shows that there exists no well-defined boundary in the evolution from the strain glass transition to the new phase transition. Due to its generality, this glass mediated phase transition divergence scheme can be applied to other proper material systems to induce a more important new phase transition path, which can be useful in the field of phase transition engineering.
8. NASA's Space Launch System Transitions From Design To Production
NASA Technical Reports Server (NTRS)
Askins, Bruce R.; Robinson, Kimberly F.
2016-01-01
NASA's Space Launch System (SLS) successfully completed its Critical Design Review (CDR) in 2015, a major milestone on the journey to an unprecedented era of exploration for humanity. CDR formally marked the program's transition from design to production phase just four years after the program's inception and the first such milestone for a human launch vehicle in 40 years. While challenges typical of a complex development program lie ahead, CDR evaluators concluded that the design is technically and programmatically sound and ready to press forward to Design Certification Review (DCR) and readiness for launch of Exploration Mission 1 (EM-1) in the 2018 timeframe. SLS is prudently based on existing propulsion systems, infrastructure and knowledge with a clear, evolutionary path as required by mission needs. In its initial configuration, designated Block 1, SLS will a minimum of 70 metric tons (t) (154,324 pounds) of payload to low Earth orbit (LEO). It will evolve to a 130 t (286,601 pound) payload capacity by upgrading its engines, boosters, and upper stage, dramatically increasing the mass and volume of human and robotic exploration while decreasing mission risk, increasing safety, and simplifying ground and mission operations. CDR was the central programmatic accomplishment among many technical accomplishments that will be described in this paper. The government/industry SLS team successfully test-fired a flight-like five-segment solid rocket motor, as well as seven hotfire development tests of the RS-25 core stage engine. The majority of the major test article and flight barrels, rings, and domes for the core stage liquid oxygen, liquid hydrogen, engine section, intertank, and forward skirt were manufactured at NASA's Michoud Assembly Facility in New Orleans, Louisiana. Renovations to the B-2 test stand for stage green run testing were completed at NASA's Stennis Space Center (SSC), near Bay St. Louis, Mississippi. Core stage test stands are reaching completion
9. NASA's Space Launch Transitions: From Design to Production
NASA Technical Reports Server (NTRS)
2016-01-01
NASA's Space Launch System (SLS) successfully completed its Critical Design Review (CDR) in 2015, a major milestone on the journey to an unprecedented era of exploration for humanity. CDR formally marked the program's transition from design to production phase just four years after the program's inception and the first such milestone for a human launch vehicle in 40 years. While challenges typical of a complex development program lie ahead, CDR evaluators concluded that the design is technically and programmatically sound and ready to press forward to Design Certification Review (DCR) and readiness for launch of Exploration Mission 1 (EM-1) in the 2018 timeframe. SLS is prudently based on existing propulsion systems, infrastructure and knowledge with a clear, evolutionary path as required by mission needs. In its initial configuration, designated Block I, SLS will a minimum of 70 metric tons (t) of payload to low Earth orbit (LEO). It can evolve to a 130 t payload capacity by upgrading its engines, boosters, and upper stage, dramatically increasing the mass and volume of human and robotic exploration while decreasing mission risk, increasing safety, and simplifying ground and mission operations. CDR was the central programmatic accomplishment among many technical accomplishments that will be described in this paper. The government/industry SLS team successfully test fired a flight-like five-segment solid rocket motor, as well as seven hotfire development tests of the RS-25 core stage engine. The majority of the major test article and flight barrels, rings, and domes for the core stage liquid oxygen, liquid hydrogen, engine section, intertank, and forward skirt were manufactured at NASA's Michoud Assembly Facility. Renovations to the B-2 test stand for stage green run testing were completed at NASA Stennis Space Center. Core stage test stands are rising at NASA Marshall Space Flight Center. The modified Pegasus barge for core stage transportation from manufacturing
10. Resilience-based application of state-and-transition models
Technology Transfer Automated Retrieval System (TEKTRAN)
We recommend that several conceptual modifications be incorporated into the state-and-transition model (STM) framework to: 1) explicitly link this framework to the concept of ecological resilience, 2) direct management attention away from thresholds and toward the maintenance of state resilience, an...
11. State-to-State Mode Specificity: Energy Sequestration and Flow Gated by Transition State.
PubMed
Zhao, Bin; Sun, Zhigang; Guo, Hua
2015-12-23
Energy flow and sequestration at the state-to-state level are investigated for a prototypical four-atom reaction, H2 + OH → H + H2O, using a transition-state wave packet (TSWP) method. The product state distribution is found to depend strongly on the reactant vibrational excitation, indicating mode specificity at the state-to-state level. From a local-mode perspective, it is shown that the vibrational excitation of the H2O product derives from two different sources, one attributable to the energy flow along the reaction coordinate into the newly formed OH bond and the other due to the sequestration of the vibrational energy in the OH spectator moiety during the reaction. The analysis provided a unified interpretation of some seemingly contradicting experimental observations. It is further shown that the transfer of vibrational energy from the OH reactant to H2O product is gated by the transition state, accomplished coherently by multiple TSWPs with the corresponding OH vibrational excitation. PMID:26613942
12. Exploring the phase space of multiple states in highly turbulent Taylor-Couette flow
van der Veen, Roeland C. A.; Huisman, Sander G.; Dung, On-Yu; Tang, Ho L.; Sun, Chao; Lohse, Detlef
2016-06-01
We investigate the existence of multiple turbulent states in highly turbulent Taylor-Couette flow in the range of Ta =1011 to 9 ×1012 by measuring the global torques and the local velocities while probing the phase space spanned by the rotation rates of the inner and outer cylinders. The multiple states are found to be very robust and are expected to persist beyond Ta =1013 . The rotation ratio is the parameter that most strongly controls the transitions between the flow states; the transitional values only weakly depend on the Taylor number. However, complex paths in the phase space are necessary to unlock the full region of multiple states. By mapping the flow structures for various rotation ratios in a Taylor-Couette setup with an equal radius ratio but a larger aspect ratio than before, multiple states are again observed. Here they are characterized by even richer roll structure phenomena, including an antisymmetrical roll state.
13. Glycosidase inhibition: assessing mimicry of the transition state
PubMed Central
2010-01-01
Glycoside hydrolases, the enzymes responsible for hydrolysis of the glycosidic bond in di-, oligo- and polysaccharides, and glycoconjugates, are ubiquitous in Nature and fundamental to existence. The extreme stability of the glycosidic bond has meant these enzymes have evolved into highly proficient catalysts, with an estimated 1017 fold rate enhancement over the uncatalysed reaction. Such rate enhancements mean that enzymes bind the substrate at the transition state with extraordinary affinity; the dissociation constant for the transition state is predicted to be 10–22 M. Inhibition of glycoside hydrolases has widespread application in the treatment of viral infections, such as influenza and HIV, lysosomal storage disorders, cancer and diabetes. If inhibitors are designed to mimic the transition state, it should be possible to harness some of the transition state affinity, resulting in highly potent and specific drugs. Here we examine a number of glycosidase inhibitors which have been developed over the past half century, either by Nature or synthetically by man. A number of criteria have been proposed to ascertain which of these inhibitors are true transition state mimics, but these features have only be critically investigated in a very few cases. PMID:20066263
14. The transition to the metallic state in low density hydrogen
DOE PAGESBeta
McMinis, Jeremy; Morales, Miguel A.; Ceperley, David M.; Kim, Jeongnim
2015-11-18
Solid atomic hydrogen is one of the simplest systems to undergo a metal-insulator transition. Near the transition, the electronic degrees of freedom become strongly correlated and their description provides a difficult challenge for theoretical methods. As a result, the order and density of the phase transition are still subject to debate. In this work we use diffusion quantum Monte Carlo to benchmark the transition between the paramagnetic and anti-ferromagnetic phases of ground state body centered cubic atomic hydrogen. We locate the density of the transition by computing the equation of state for these two phases and identify the phase transitionmore » order by computing the band gap near the phase transition. These benchmark results show that the phase transition is continuous and occurs at a Wigner-Seitz radius of rs = 2.27(3)a0. As a result, we compare our results to previously reported density functional theory, Hedin s GW approximation, and dynamical mean field theory results.« less
15. Reshaping the College Transition: Early College Readiness Assessments and Transition Curricula in Four States. A State Policy Report
ERIC Educational Resources Information Center
Barnett, Elisabeth A.; Fay, Maggie P.; Trimble, Madeline Joy; Pheatt, Lara
2013-01-01
Based largely on interviews with stakeholders in California, New York, Tennessee, and West Virginia, this report describes how these states have established initiatives related to early college readiness assessments and transition curricula. It then compares the development of these interventions across states and identifies factors that have…
16. Granger causality for state-space models
Barnett, Lionel; Seth, Anil K.
2015-04-01
Granger causality has long been a prominent method for inferring causal interactions between stochastic variables for a broad range of complex physical systems. However, it has been recognized that a moving average (MA) component in the data presents a serious confound to Granger causal analysis, as routinely performed via autoregressive (AR) modeling. We solve this problem by demonstrating that Granger causality may be calculated simply and efficiently from the parameters of a state-space (SS) model. Since SS models are equivalent to autoregressive moving average models, Granger causality estimated in this fashion is not degraded by the presence of a MA component. This is of particular significance when the data has been filtered, downsampled, observed with noise, or is a subprocess of a higher dimensional process, since all of these operations—commonplace in application domains as diverse as climate science, econometrics, and the neurosciences—induce a MA component. We show how Granger causality, conditional and unconditional, in both time and frequency domains, may be calculated directly from SS model parameters via solution of a discrete algebraic Riccati equation. Numerical simulations demonstrate that Granger causality estimators thus derived have greater statistical power and smaller bias than AR estimators. We also discuss how the SS approach facilitates relaxation of the assumptions of linearity, stationarity, and homoscedasticity underlying current AR methods, thus opening up potentially significant new areas of research in Granger causal analysis.
17. Topological properties of flat electroencephalography's state space
Ken, Tan Lit; Ahmad, Tahir bin; Mohd, Mohd Sham bin; Ngien, Su Kong; Suwa, Tohru; Meng, Ong Sie
2016-02-01
Neuroinverse problem are often associated with complex neuronal activity. It involves locating problematic cell which is highly challenging. While epileptic foci localization is possible with the aid of EEG signals, it relies greatly on the ability to extract hidden information or pattern within EEG signals. Flat EEG being an enhancement of EEG is a way of viewing electroencephalograph on the real plane. In the perspective of dynamical systems, Flat EEG is equivalent to epileptic seizure hence, making it a great platform to study epileptic seizure. Throughout the years, various mathematical tools have been applied on Flat EEG to extract hidden information that is hardly noticeable by traditional visual inspection. While these tools have given worthy results, the journey towards understanding seizure process completely is yet to be succeeded. Since the underlying structure of Flat EEG is dynamic and is deemed to contain wealthy information regarding brainstorm, it would certainly be appealing to explore in depth its structures. To better understand the complex seizure process, this paper studies the event of epileptic seizure via Flat EEG in a more general framework by means of topology, particularly, on the state space where the event of Flat EEG lies.
18. Analysis of slow transitions between nonequilibrium steady states
Mandal, Dibyendu; Jarzynski, Christopher
2016-06-01
Transitions between nonequilibrium steady states obey a generalized Clausius inequality, which becomes an equality in the quasistatic limit. For slow but finite transitions, we show that the behavior of the system is described by a response matrix whose elements are given by a far-from-equilibrium Green–Kubo formula, involving the decay of correlations evaluated in the nonequilibrium steady state. This result leads to a fluctuation-dissipation relation between the mean and variance of the nonadiabatic entropy production, Δ {{s}\\text{na}} . Furthermore, our results extend—to nonequilibrium steady states—the thermodynamic metric structure introduced by Sivak and Crooks for analyzing minimal-dissipation protocols for transitions between equilibrium states.
19. OptZyme: Computational Enzyme Redesign Using Transition State Analogues
PubMed Central
Grisewood, Matthew J.; Gifford, Nathanael P.; Pantazes, Robert J.; Li, Ye; Cirino, Patrick C.; Janik, Michael J.; Maranas, Costas D.
2013-01-01
OptZyme is a new computational procedure for designing improved enzymatic activity (i.e., kcat or kcat/KM) with a novel substrate. The key concept is to use transition state analogue compounds, which are known for many reactions, as proxies for the typically unknown transition state structures. Mutations that minimize the interaction energy of the enzyme with its transition state analogue, rather than with its substrate, are identified that lower the transition state formation energy barrier. Using Escherichia coli β-glucuronidase as a benchmark system, we confirm that KM correlates (R2 = 0.960) with the computed interaction energy between the enzyme and the para-nitrophenyl- β, D-glucuronide substrate, kcat/KM correlates (R2 = 0.864) with the interaction energy of the transition state analogue, 1,5-glucarolactone, and kcat correlates (R2 = 0.854) with a weighted combination of interaction energies with the substrate and transition state analogue. OptZyme is subsequently used to identify mutants with improved KM, kcat, and kcat/KM for a new substrate, para-nitrophenyl- β, D-galactoside. Differences between the three libraries reveal structural differences that underpin improving KM, kcat, or kcat/KM. Mutants predicted to enhance the activity for para-nitrophenyl- β, D-galactoside directly or indirectly create hydrogen bonds with the altered sugar ring conformation or its substituents, namely H162S, L361G, W549R, and N550S. PMID:24116038
20. Global Infrared Observations of Roughness Induced Transition on the Space Shuttle Orbiter
NASA Technical Reports Server (NTRS)
Horvath, Thomas J.; Zalameda, Joseph N.; Wood, William A.; Berry, Scott A.; Schwartz, Richard J.; Dantowitz, Ronald F.; Spisz, Thomas S.; Taylor, Jeff C.
2012-01-01
High resolution infrared observations made from a mobile ground based optical system captured the laminar-to-turbulent boundary layer transition process as it occurred during Space Shuttle Endeavour's return to earth following its final mission in 2011. The STS-134 imagery was part of a larger effort to demonstrate an emerging and reliable non-intrusive global thermal measurement capability and to complement a series of boundary layer transition flight experiments that were flown on the Shuttle. The STS-134 observations are believed to be the first time that the development and movement of a hypersonic boundary layer transition front has been witnessed in flight over the entire vehicle surface and in particular, at unprecedented spatial resolution. Additionally, benchmark surface temperature maps of the Orbiter lower surface collected over multiple flights and spanning a Mach range of 18 to 6 are now available and represent an opportunity for collaborative comparison with computational techniques focused on hypersonic transition and turbulence modeling. The synergy of the global temperature maps with the companion in-situ thermocouple measurements serve as an example of the effective leveraging of resources to achieve a common goal of advancing our understanding of the complex nature of high Mach number transition. It is shown that quantitative imaging can open the door to a multitude of national and international opportunities for partnership associated with flight-testing and subsequent validation of numerical simulation techniques. The quantitative imaging applications highlighted in this paper offer unique and complementary flight measurement alternatives and suggest collaborative instrumentation opportunities to advance the state of the art in transition prediction and maximize the return on investment in terms of developmental flight tests for future vehicle designs.
1. Space science in the United States
NASA Technical Reports Server (NTRS)
Alexander, Joseph K.; Mcdonald, Frank B.
1988-01-01
Despite the hiatus in spacecraft launches after the Space Shuttle Challenger accident in 1986, the U.S. space program continues to generate research data on the basis of the productive operation of 18 scientific spacecraft. Attention is presently given to NASA's planned missions for the 1990s in such fields as astronomy and astrophysics (the Hubble Space Telescope, the Extreme UV Explorer), solar system exploration (the Magellan Venus orbiter, the Galileo Jupiter orbiter), space physics (the Tethered Satellite System, the Combined Release and Radiation Effects Satellite), earth science (the Upper Atmospheric Research Satellite), and microgravity sciences (the International Microgravity Observatory).
2. Columbus State University Global Observation and Outreach for the 2012 Transit of Venus
Perry, Matthew; McCarty, C.; Bartow, M.; Hood, J. C.; Lodder, K.; Johnson, M.; Cruzen, S. T.; Williams, R. N.
2013-01-01
Faculty, staff and students from Columbus State University’s (CSU’s) Coca-Cola Space Science Center presented a webcast of the 2012 Transit of Venus from three continents to a global audience of 1.4 million unique viewers. Team members imaged the transit with telescopes using white-light, hydrogen-alpha, and calcium filters, from Alice Springs, Australia; the Gobi Desert, Mongolia; Bryce Canyon, UT; and Columbus, GA. Images were webcast live during the transit in partnership with NASA’s Sun-Earth Day program, and Science Center staff members were featured on NASA TV. Local members of the public were brought in for a series of outreach initiatives, in both Georgia and Australia, before and during the transit. The data recorded from the various locations have been archived for use in demonstrating principles such as the historical measurement of the astronomical unit.
3. Destination state screening of active spaces in spin dynamics simulations
Krzystyniak, M.; Edwards, Luke J.; Kuprov, Ilya
2011-06-01
We propose a novel avenue for state space reduction in time domain Liouville space spin dynamics simulations, using detectability as a selection criterion - only those states that evolve into or affect other detectable states are kept in the simulation. This basis reduction procedure (referred to as destination state screening) is formally exact and can be applied on top of the existing state space restriction techniques. As demonstrated below, in many cases this results in further reduction of matrix dimension, leading to considerable acceleration of many spin dynamics simulation types. Destination state screening is implemented in the latest version of the Spinach library (http://spindynamics.org).
4. Steady-state plasma transition in the Venus ionosheath
NASA Technical Reports Server (NTRS)
Perez-De-tejada, H.; Intriligator, D. S.; Strangeway, R. J.
1991-01-01
The results of an extended analysis of the plasma and electric field data of the Pioneer Venus Orbiter (PVO) are presented. The persistent presence of a plasma transition embedded in the flanks of the Venus ionosheath between the bow shock and the ionopause is reported. This transition is identified by the repeated presence of characteristic bursts in the 30 kHz channel of the electric field detector of the PVO. The observed electric field signals coincide with the onset of different plasma conditions in the inner ionosheath where more rarified plasma fluxes are measured. The repeated identification of this intermediate ionosheath transition in the PVO data indicates that it is present as a steady state feature of the Venus plasma environment. The distribution of PVO orbits in which the transition is observed suggests that it is more favorably detected in the vicinity of and downstream from the terminator.
5. Transition paths of Met-enkephalin from Markov state modeling of a molecular dynamics trajectory.
PubMed
Banerjee, Rahul; Cukier, Robert I
2014-03-20
Conformational states and their interconversion pathways of the zwitterionic form of the pentapeptide Met-enkephalin (MetEnk) are identified. An explicit solvent molecular dynamics (MD) trajectory is used to construct a Markov state model (MSM) based on dihedral space clustering of the trajectory, and transition path theory (TPT) is applied to identify pathways between open and closed conformers. In the MD trajectory, only four of the eight backbone dihedrals exhibit bistable behavior. Defining a conformer as the string XXXX with X = "+" or "-" denoting, respectively, positive or negative values of a given dihedral angle and obtaining the populations of these conformers shows that only four conformers are highly populated, implying a strong correlation among these dihedrals. Clustering in dihedral space to construct the MSM finds the same four bistable dihedral angles. These state populations are very similar to those found directly from the MD trajectory. TPT is used to obtain pathways, parametrized by committor values, in dihedral state space that are followed in transitioning from closed to open states. Pathway costs are estimated by introducing a kinetics-based procedure that orders pathways from least (shortest) to greater cost paths. The least costly pathways in dihedral space are found to only involve the same XXXX set of dihedral angles, and the conformers accessed in the closed to open transition pathways are identified. For these major pathways, a correlation between reaction path progress (committors) and the end-to-end distance is identified. A dihedral space principal component analysis of the MD trajectory shows that the first three modes capture most of the overall fluctuation, and pick out the same four dihedrals having essentially all the weight in those modes. A MSM based on root-mean-square backbone clustering was also carried out, with good agreement found with dihedral clustering for the static information, but with results that differ
6. Leading the Transition from Classrooms to Learning Spaces
ERIC Educational Resources Information Center
Oblinger, Diana
2005-01-01
A number of factors are prompting higher education's interest in learning spaces: the need to renovate existing space or accommodate additional students, pedagogical advances, a better understanding of learners, and, in some cases, curricular reform. Moving from classrooms to learning spaces involves a conceptual shift as well as a commitment to…
7. Catching Up on State Transitions in Cygnus X-1
NASA Technical Reports Server (NTRS)
Boeck, Moritz; Hanke, Manfred; Wilms, Joern; Pirner, Stefan; Grinberg, Victoria; Markoff, Sera; Pottschmidt, Katja; Nowak, Michael A.; Pooley, Guy
2008-01-01
In 2005 February we observed Cygnus X-1 over a period of 10 days quasi-continuously with the Rossi X-ray Timing Explorer and the Ryle telescope. We present the results of the spectral and timing analysis on a timescale of 90 min and show that the behavior of Cyg X-1 is similar to that found during our years long monitoring campaign. As a highlight we present evidence for a full transition from the hard to the soft state that happened during less than three hours. The observation provided a more complete picture of a state transition than before, especially concerning the evolution of the time lags, due to unique transition coverage and analysis with high time resolution.
8. How to upload a physical quantum state into correlation space
SciTech Connect
Morimae, Tomoyuki
2011-04-15
9. The State-of-the-art in Space Robotics
da Fonseca, Ijar M.; Pontuschka, Maurício N.
2015-10-01
This paper deals with the space robotics and associate space applications. An overview of the space era and the robotic space probes is presented to contextualize the space robotics in the space exploration scenario. Concepts, classification and key-questions associated with robotics for space applications are presented and discussed. Safety-critical aspects of the space robotics are discussed as well the human limitation to operate in the hostile space environment and long time duration missions. The paper also focuses on the state-of-the- art of robotics for the International Space Station EVA operations, for the planetary exploration such as the ongoing Mars exploration, Hayabusa rendezvous and landing in asteroids and the robotic probe Rosetta landed in a comet recently. The paper also includes a discussion of the applications of new concepts like the robonauts, the space tugs applications and robots for future planetary exploration.
10. Metal-insulator transition near a superconducting state
Kaveh, M.; Mott, N. F.
1992-03-01
We show that when the metal-insulation transition occurs near a superconducting state it results in a different critical behavior from that of amorphous metals or uncompensated doped semiconductors. This difference results from the enhancement of the effective electron-electron interaction caused by fluctuations to the superconducting state. This explains the recent experiments of Micklitz and co-workers on amorphous superconducting mixtures Ga-Ar and Bi-Kr.
11. Cosmic evolution from phase transition of three-dimensional flat space.
PubMed
Bagchi, Arjun; Detournay, Stephane; Grumiller, Daniel; Simón, Joan
2013-11-01
Flat space cosmology spacetimes are exact time-dependent solutions of three-dimensional gravity theories, such as Einstein gravity or topologically massive gravity. We exhibit a novel kind of phase transition between these cosmological spacetimes and the Minkowski vacuum. At sufficiently high temperature, (rotating) hot flat space tunnels into a universe described by flat space cosmology. PMID:24237503
12. Storing excitons in transition-metal dichalcogenides using dark states
Gunlycke, Daniel; Tseng, Frank; Simsek, Ergun
Monolayer transition-metal dichalcogenides exhibit strongly bound excitons confined to two dimensions. One challenge in exploiting these excitons is that they have a finite life time and collapse through electron-hole recombination. We propose that the exciton life time could be extended by transitioning the exciton population into dark states. The symmetry of these dark states require the electron and hole to be spatially separated, which not only causes these states to be optically inactive but also inhibits electron-hole recombination. Based on an atomistic model we call the Triangular Lattice Exciton (3ALE) model, we derive transition matrix elements and approximate selection rules showing that excitons could be transitioned into and out of dark states using a pulsed infrared laser. For illustration, we also present exciton population scenarios based on different recombination decay constants. Longer exciton lifetimes could make these materials candidates for applications in energy management and quantum information processing. This work was supported by the Office of Naval Research, directly and through the Naval Research Laboratory.
13. Current status of the state-and-transition framework
Technology Transfer Automated Retrieval System (TEKTRAN)
State-and-transition models (STM) have been widely adopted as a tool for explaining plant community dynamics and response to disturbance within rangeland ecosystems. Our understanding of the STM concepts has advanced substantially since they were introduced by Westoby et al. (1989) and modified by ...
14. Absorbing-state phase transitions with extremal dynamics
Dickman, Ronald; Garcia, Guilherme J. M.
2005-06-01
Extremal dynamics represents a path to self-organized criticality in which the order parameter is tuned to a value of zero. The order parameter is associated with a phase transition to an absorbing state. Given a process that exhibits a phase transition to an absorbing state, we define an “extremal absorbing” process, providing the link to the associated extremal (nonabsorbing) process. Stationary properties of the latter correspond to those at the absorbing-state phase transition in the former. Studying the absorbing version of an extremal dynamics model allows to determine certain critical exponents that are not otherwise accessible. In the case of the Bak-Sneppen (BS) model, the absorbing version is closely related to the “ f -avalanche” introduced by Paczuski, Maslov, and Bak [Phys. Rev. E 53, 414 (1996)], or, in spreading simulations to the “BS branching process” also studied by these authors. The corresponding nonextremal process belongs to the directed percolation universality class. We revisit the absorbing BS model, obtaining refined estimates for the threshold and critical exponents in one dimension. We also study an extremal version of the usual contact process, using mean-field theory and simulation. The extremal condition slows the spread of activity and modifies the critical behavior radically, defining an “extremal directed percolation” universality class of absorbing-state phase transitions. Asymmetric updating is a relevant perturbation for this class, even though it is irrelevant for the corresponding nonextremal class.
15. 40 CFR 70.4 - State program submittals and transition.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 15 2010-07-01 2010-07-01 false State program submittals and transition. 70.4 Section 70.4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR..., including authority to carry out each of the following: (i) Issue permits and assure compliance with...
16. Practical guidance for developing state-and-transition models
Technology Transfer Automated Retrieval System (TEKTRAN)
State-and-transition models (STMs) are synthetic descriptions of the dynamics of vegetation and surface soils occurring within specific ecological sites. STMs consist of a diagram and narratives that describe the dynamics and its causes. STMs are developed using a broad array of evidence including h...
17. Spatially-explicit representation of state-and-transition models
Technology Transfer Automated Retrieval System (TEKTRAN)
The broad-scale assessment of natural resource conditions (e.g., rangeland health, restoration needs) requires knowledge of their spatial distribution. We argue that creating a database that links state-and-transition models (STMs) to spatial units is a valuable management tool for structuring groun...
18. State Accountability in the Transition to Common Core. Updated
ERIC Educational Resources Information Center
Sears, Victoria
2014-01-01
The Common Core is at a critical juncture. While many surveys show that support for the standards themselves remains strong, implementation has not been without major challenges. "State Accountability in the Transition to Common Core," a new policy brief from the Thomas B. Fordham Institute, provides cautionary advice about what key…
19. Theoretical analysis of droplet transition from Cassie to Wenzel state
Liu, Tian-Qing; Yan-Jie, Li; Xiang-Qin, Li; Wei, Sun
2015-11-01
Whether droplets transit from the Cassie to the Wenzel state (C-W) on a textured surface is the touchstone that the superhydrophobicity of the surface is still maintained. However, the C-W transition mechanism, especially the spontaneous transition of small droplets, is still not very clear to date. The interface free energy gradient of a small droplet is firstly proposed and derived as the driving force for its C-W evolution in this study based on the energy and gradient analysis. Then the physical and mathematical model of the C-W transition is found after the C-W driving force or transition pressure, the resistance, and the parameters of the meniscus beneath the droplet are formulated. The results show that the micro/nano structural parameters significantly affect the C-W driving force and resistance. The smaller the pillar diameter and pitch, the minor the C-W transition pressure, and the larger the resistance. Consequently, the C-W transition is difficult to be completed for the droplets on nano-textured surfaces. Meanwhile if the posts are too short, the front of the curved liquid-air interface below the droplet will touch the structural substrate easily even though the three phase contact line (TPCL) has not depinned. When the posts are high enough, the TPCL beneath the drop must move firstly before the meniscus can reach the substrate. As a result, the droplet on a textured surface with short pillars is easy to complete its C-W evolution. On the other hand, the smaller the droplet, the easier the C-W shift, since the transition pressure becomes larger, which well explains why an evaporating drop will collapse spontaneously from composite to Wenzel state. Besides, both intrinsic and advancing contact angles affect the C-W transition as well. The greater the two angles, the harder the C-W transition. In the end, the C-W transition parameters and the critical conditions measured in literatures are calculated and compared, and the calculations accord well with
20. State-space size considerations for disease-progression models.
PubMed
Regnier, Eva D; Shechter, Steven M
2013-09-30
Markov models of disease progression are widely used to model transitions in patients' health state over time. Usually, patients' health status may be classified according to a set of ordered health states. Modelers lump together similar health states into a finite and usually small, number of health states that form the basis of a Markov chain disease-progression model. This increases the number of observations used to estimate each parameter in the transition probability matrix. However, lumping together observably distinct health states also obscures distinctions among them and may reduce the predictive power of the model. Moreover, as we demonstrate, precision in estimating the model parameters does not necessarily improve as the number of states in the model declines. This paper explores the tradeoff between lumping error introduced by grouping distinct health states and sampling error that arises when there are insufficient patient data to precisely estimate the transition probability matrix. PMID:23609629
1. Specificity in Transition State Binding: The Pauling Model Revisited
PubMed Central
Amyes, Tina L.; Richard, John P.
2013-01-01
Linus Pauling proposed that the large rate accelerations for enzymes are due to the high specificity of the protein catalyst for binding the reaction transition state. The observation that stable analogs of the transition states for enzymatic reactions often act as tight-binding binding inhibitors provided early support for this simple and elegant proposal. We review experimental results which support the proposal that Pauling’s model provides a satisfactory explanation for the rate accelerations for many heterolytic enzymatic reactions through high energy reaction intermediates, such as proton transfer and decarboxylation. Specificity in transition state binding is obtained when the total intrinsic binding energy of the substrate is significantly larger than the binding energy observed at the Michaelis complex. The results of recent studies to characterize the specificity in binding of the enolate oxygen at the transition state for the 1,3-isomerization reaction catalyzed by ketosteroid isomerase are reviewed. Interactions between pig heart succinyl-CoA:3-oxoacid coenzyme A transferase (SCOT) and the nonreacting portions of CoA are responsible for a rate increase of 3 × 1012-fold, which is close to the estimated total 5 × 1013-fold enzymatic rate acceleration. Studies that partition the interactions between SCOT and CoA into their contributing parts are reviewed. Interactions of the protein with the substrate phosphodianion group provide a ca. 12 kcal/mol stabilization of the transition state for the reactions catalyzed by triosephosphate isomerase, orotidine 5′-monophosphate decarboxylase and α-glycerol phosphate dehydrogenase. The interactions of these enzymes with the substrate piece phosphite dianion provide a 6 – 8 kcal/mol stabilization of the transition state for reaction of the appropriate truncated substrate. Enzyme activation by phosphite dianion reflects the higher dianion affinity for binding to the enzyme-transition state complex compared
2. Transition state-finding strategies for use with the growing string method
Goodrow, Anthony; Bell, Alexis T.; Head-Gordon, Martin
2009-06-01
Efficient identification of transition states is important for understanding reaction mechanisms. Most transition state search algorithms require long computational times and a good estimate of the transition state structure in order to converge, particularly for complex reaction systems. The growing string method (GSM) [B. Peters et al., J. Chem. Phys. 120, 7877 (2004)] does not require an initial guess of the transition state; however, the calculation is still computationally intensive due to repeated calls to the quantum mechanics code. Recent modifications to the GSM [A. Goodrow et al., J. Chem. Phys. 129, 174109 (2008)] have reduced the total computational time for converging to a transition state by a factor of 2 to 3. In this work, three transition state-finding strategies have been developed to complement the speedup of the modified-GSM: (1) a hybrid strategy, (2) an energy-weighted strategy, and (3) a substring strategy. The hybrid strategy initiates the string calculation at a low level of theory (HF/STO-3G), which is then refined at a higher level of theory (B3LYP/6-31G∗). The energy-weighted strategy spaces points along the reaction pathway based on the energy at those points, leading to a higher density of points where the energy is highest and finer resolution of the transition state. The substring strategy is similar to the hybrid strategy, but only a portion of the low-level string is refined using a higher level of theory. These three strategies have been used with the modified-GSM and are compared in three reactions: alanine dipeptide isomerization, H-abstraction in methanol oxidation on VOx/SiO2 catalysts, and C-H bond activation in the oxidative carbonylation of toluene to p-toluic acid on Rh(CO)2(TFA)3 catalysts. In each of these examples, the substring strategy was proved most effective by obtaining a better estimate of the transition state structure and reducing the total computational time by a factor of 2 to 3 compared to the modified
3. The morphological state space revisited: what do phylogenetic patterns in homoplasy tell us about the number of possible character states?
PubMed
Hoyal Cuthill, Jennifer F
2015-12-01
Biological variety and major evolutionary transitions suggest that the space of possible morphologies may have varied among lineages and through time. However, most models of phylogenetic character evolution assume that the potential state space is finite. Here, I explore what the morphological state space might be like, by analysing trends in homoplasy (repeated derivation of the same character state). Analyses of ten published character matrices are compared against computer simulations with different state space models: infinite states, finite states, ordered states and an 'inertial' model, simulating phylogenetic constraints. Of these, only the infinite states model results in evolution without homoplasy, a prediction which is not generally met by real phylogenies. Many authors have interpreted the ubiquity of homoplasy as evidence that the number of evolutionary alternatives is finite. However, homoplasy is also predicted by phylogenetic constraints on the morphological distance that can be traversed between ancestor and descendent. Phylogenetic rarefaction (sub-sampling) shows that finite and inertial state spaces do produce contrasting trends in the distribution of homoplasy. Two clades show trends characteristic of phylogenetic inertia, with decreasing homoplasy (increasing consistency index) as we sub-sample more distantly related taxa. One clade shows increasing homoplasy, suggesting exhaustion of finite states. Different clades may, therefore, show different patterns of character evolution. However, when parsimony uninformative characters are excluded (which may occur without documentation in cladistic studies), it may no longer be possible to distinguish inertial and finite state spaces. Interestingly, inertial models predict that homoplasy should be clustered among comparatively close relatives (parallel evolution), whereas finite state models do not. If morphological evolution is often inertial in nature, then homoplasy (false homology) may primarily
4. Using Brain Imaging to Track Problem Solving in a Complex State Space
PubMed Central
Anderson, John R.; Fincham, Jon M.; Schneider, Darryl W.; Yang, Jian
2011-01-01
This paper describes how behavioral and imaging data can be combined with a Hidden Markov Model (HMM) to track participants’ trajectories through a complex state space. Participants completed a problem-solving variant of a memory game that involved 625 distinct states, 24 operators, and an astronomical number of paths through the state space. Three sources of information were used for classification purposes. First, an Imperfect Memory Model was used to estimate transition probabilities for the HMM. Second, behavioral data provided information about the timing of different events. Third, multivoxel pattern analysis of the imaging data was used to identify features of the operators. By combining the three sources of information, an HMM algorithm was able to efficiently identify the most probable path that participants took through the state space, achieving over 80% accuracy. These results support the approach as a general methodology for tracking mental states that occur during individual problem-solving episodes. PMID:22209783
5. State transitions of actin cortices in vitro and in vivo
Tan, Tzer Han; Keren, Kinneret; Mackintosh, Fred; Schmidt, Christoph; Fakhri, Nikta
Most animal cells are enveloped by a thin layer of actin cortex which governs the cell mechanics. A functional cortex must be rigid to provide mechanical support while being flexible to allow for rapid restructuring events such as cell division. To satisfy these requirements, the actin cortex is highly dynamic with fast actin turnover and myosin-driven contractility. The regulatory mechanism responsible for the transition between a mechanically stable state and a restructuring state is not well understood. Here, we develop a technique to map the dynamics of reconstituted actin cortices in emulsion droplets using IR fluorescent single-walled carbon nanotubes (SWNTs). By increasing crosslinker concentration, we find that a homogeneous cortex transitions to an intermediate state with broken rotational symmetry and a globally contractile state which further breaks translational symmetry. We apply this new dynamic mapping technique to cortices of live starfish oocytes in various developmental stages. To identify the regulatory mechanism for steady state transitions, we subject the oocytes to actin and myosin disrupting drugs.
6. State transitions in geomorphic responses to environmental change
Phillips, Jonathan D.
2014-01-01
The fundamental geomorphic responses to environmental change are qualitative changes in system states. This study is concerned with the complexity of state transition models (STM), and synchronization. The latter includes literal and inferential synchronization, the extent to which observations or relationships at one time period can be applied to others. Complexity concerns the extent to which STM structure may tend to amplify effects of change. Three metrics-spectral radius, Laplacian spectral radius, and algebraic connectivity-were applied to several generic geomorphic STMs, and to three real-world examples: the San Antonio River delta, soil transitions in a coastal plain agricultural landscape, and high-latitude thermokarst systems. While the Laplacian spectral radius was of limited use, spectral radius and algebraic complexity provide significant, independent information. The former is more sensitive to the intensity of cycles within the transition graph structure, and to the overall complexity of the STM. Spectral radius is an effective general index of graph complexity, and especially the likelihood of amplification and intensification of changes in environmental boundary conditions, or of the propagation of local disturbances within the system. The spectral radius analyses here illustrate that more information does not necessarily decrease uncertainty, as increased information often results in the expansion of state transition networks from simpler linear sequential and cyclic to more complex structures. Algebraic connectivity applied to landscape-scale STMs provides a measure of the likelihood of complex response, with synchronization inversely related to complex response.
7. Raman transitions between hyperfine clock states in a magnetic trap
Naber, J. B.; Torralbo-Campo, L.; Hubert, T.; Spreeuw, R. J. C.
2016-07-01
We present our experimental investigation of an optical Raman transition between the magnetic clock states of 87Rb in an atom chip magnetic trap. The transfer of atomic population is induced by a pair of diode lasers which couple the two clock states off-resonantly to an intermediate state manifold. This transition is subject to destructive interference of two excitation paths, which leads to a reduction of the effective two-photon Rabi frequency. Furthermore, we find that the transition frequency is highly sensitive to the intensity ratio of the diode lasers. Our results are well described in terms of light shifts in the multilevel structure of 87Rb. The differential light shifts vanish at an optimal intensity ratio, which we observe as a narrowing of the transition linewidth. We also observe the temporal dynamics of the population transfer and find good agreement with a model based on the system's master equation and a Gaussian laser beam profile. Finally, we identify several sources of decoherence in our system, and discuss possible improvements.
8. Isotopic mapping of transition-state structural features associated with enzymic catalysis of methyl transfer
SciTech Connect
Rodgers, J.; Femec, D.A.; Schowen, R.L.
1982-06-16
For comparison of the molecular structures of nonenzymic and enzymic sulfur-to-oxygen transmethylation transition states by the use of kinetic isotope effects, a series of isotopic maps is produced. In these, contours of constant isotope effect are displayed vs. the Pauling bond orders B/sub CS/ and B/sub CO/, for the carbon-sulfur and carbon-oxygen bonds, respectively, taken as independent variables to describe the transition states. Maps are calculated by the BEBOVIB approach for k(CH/sub 3/)/k(CD/sub 3/), k(/sup 12/CH/sub 3/)/k(/sup 13/CH/sub 3/), k(/sup 16/O)/k(/sup 18/O), and k(/sup 32/S)/k(/sup 34/S), with two models for the reaction coordinate, two force-field assumptions, and four temperatures. Nonenzymic isotope effects and isotope effects for catechol-O-methyltransferase action are then used to construct figures on the CH/sub 3//CD/sub 3/ and /sup 12/CH/sub 3///sup 13/CH/sub 3/ maps which correspond to allowed spaces of transition-states structures. Superposition of the figures yields the spaces of transition-state structures simultaneously consistent with both hydrogen and carbon isotope effects. It is concluded that the enzyme compresses the S/sub N/2 transition state and that the compression of the C-O and C-S bonds may well be of the order of 0.15 A per bond and could conceivably be more than twice as large.
9. Priorities in national space strategies and governance of the member states of the European Space Agency
Adriaensen, Maarten; Giannopapa, Christina; Sagath, Daniel; Papastefanou, Anastasia
2015-12-01
The European Space Agency (ESA) has twenty Member States with a variety of strategic priorities and governance structures regarding their space activities. A number of countries engage in space activities exclusively though ESA, while others have also their own national space programme. Some consider ESA as their prime space agency and others have additionally their own national agency with respective programmes. The main objective of this paper is to provide an up-to date overview and a holistic assessment of strategic priorities and the national space governance structures in 20 ESA Member States. This analysis and assessment has been conducted by analysing the Member States public documents, information provided at ESA workshop on this topic and though unstructured interviews. The paper is structured to include two main elements: priorities and trends in national space strategies and space governance in ESA Member States. The first part of this paper focuses on the content and analysis of the national space strategies and indicates the main priorities and trends in Member States. The priorities are categorised with regards to technology domains, the role of space in the areas of sustainability and the motivators that boost engagement in space. These vary from one Member State to another and include with different levels of engagement in technology domains amongst others: science and exploration, navigation, Earth observation, human space flight, launchers, telecommunications, and integrated applications. Member States allocate a different role of space as enabling tool adding to the advancement of sustainability areas including: security, resources, environment and climate change, transport and communication, energy, and knowledge and education. The motivators motivating reasoning which enhances or hinders space engagement also differs. The motivators identified are industrial competitiveness, job creation, technology development and transfer, social benefits
10. State Directors of Special Education Transition Programs: State Definitions, and Real and Ideal Teacher Competencies.
ERIC Educational Resources Information Center
Beard, John; And Others
This study surveys states' mandates, definitions, and components of transition programs that assist disabled students in successfully moving to the community environment. Among the 60 state-level directors of special education surveyed, 34 state and 4 territorial directors responded to the questionnaire comprised of 8 questions, and nominated 230…
11. Adaptive importance sampling of random walks on continuous state spaces
SciTech Connect
Baggerly, K.; Cox, D.; Picard, R.
1998-11-01
The authors consider adaptive importance sampling for a random walk with scoring in a general state space. Conditions under which exponential convergence occurs to the zero-variance solution are reviewed. These results generalize previous work for finite, discrete state spaces in Kollman (1993) and in Kollman, Baggerly, Cox, and Picard (1996). This paper is intended for nonstatisticians and includes considerable explanatory material.
12. Driving transitions between quantized flow states in an atomtronic circuit
Eckel, Stephen
Superfluidity, or flow without resistance, is a macroscopic quantum effect that is present in a multitude of systems, including liquid helium, superconductors, and ultra-cold atomic gases. In superconductors, flow without resistance has led to the development of a number of useful devices. Here, I will present our work studying a superfluid analog to the rf-superconducting interference device (SQUID). Our atomtronic analog is formed in a ring-shaped Bose-Einstein condensate (BEC) of sodium atoms. Ring condensates are unique in that they can support persistent currents that are quantized. We drive transitions between persistent current states using a rotating perturbation, or weak link. Here, rotation acts as the analog to magnetic field in superconductors. In our system, a current (as viewed in the frame co-rotating with the perturbation) develops to oppose any change in rotation. If the rotation rate is sufficiently large, the critical current of the superfluid is exceeded in the weak link region, causing a transition to a state of larger persistent current. The strength of the perturbation tunes the critical rotation rates. Like the rf-SQUID, the transitions show hysteresis - rotation rates that increase the quantized current are different from those that decrease the current. The size of the hysteresis loop allows us to explore the microscopic mechanisms responsible for the transitions. In a more recent experiment, we have observed the time it takes for the first persistent current state to decay in the presence of a stationary perturbation. The measured timescales depend strongly on temperature, but in a way that suggests that other physical effects, like quantum coherence, could also play a role in the transitions between current states.
13. IRIDIUM (R): A Lockheed transition to commercial space
NASA Technical Reports Server (NTRS)
1995-01-01
At Lockheed Missiles & Space Company, the IRIDIUM commercial space program is dramatically revolutionizing spacecraft development and manufacturing processes to reduce cost while maintaining quality and reliability. This report includes the following sections: an overview of the IRIDIUM system, the Lockheed IRIDIUM project and challenges; cycle-time reduction through production reorganization; and design for manufacturing and quality.
14. PULSAR STATE SWITCHING FROM MARKOV TRANSITIONS AND STOCHASTIC RESONANCE
SciTech Connect
Cordes, J. M.
2013-09-20
Markov processes are shown to be consistent with metastable states seen in pulsar phenomena, including intensity nulling, pulse-shape mode changes, subpulse drift rates, spin-down rates, and X-ray emission, based on the typically broad and monotonic distributions of state lifetimes. Markovianity implies a nonlinear magnetospheric system in which state changes occur stochastically, corresponding to transitions between local minima in an effective potential. State durations (though not transition times) are thus largely decoupled from the characteristic timescales of various magnetospheric processes. Dyadic states are common but some objects show at least four states with some transitions forbidden. Another case is the long-term intermittent pulsar B1931+24 that has binary radio-emission and torque states with wide, but non-monotonic duration distributions. It also shows a quasi-period of 38 ± 5 days in a 13 yr time sequence, suggesting stochastic resonance in a Markov system with a forcing function that could be strictly periodic or quasi-periodic. Nonlinear phenomena are associated with time-dependent activity in the acceleration region near each magnetic polar cap. The polar-cap diode is altered by feedback from the outer magnetosphere and by return currents from the equatorial region outside the light cylinder that may also cause the neutron star to episodically charge and discharge. Orbital perturbations of a disk or current sheet provide a natural periodicity for the forcing function in the stochastic-resonance interpretation of B1931+24. Disk dynamics may introduce additional timescales in observed phenomena. Future work can test the Markov interpretation, identify which pulsar types have a propensity for state changes, and clarify the role of selection effects.
15. Absorbing-state phase transitions on percolating lattices.
PubMed
Lee, Man Young; Vojta, Thomas
2009-04-01
We study nonequilibrium phase transitions of reaction-diffusion systems defined on randomly diluted lattices, focusing on the transition across the lattice percolation threshold. To develop a theory for this transition, we combine classical percolation theory with the properties of the supercritical nonequilibrium system on a finite-size cluster. In the case of the contact process, the interplay between geometric criticality due to percolation and dynamical fluctuations of the nonequilibrium system leads to a different universality class. The critical point is characterized by ultraslow activated dynamical scaling and accompanied by strong Griffiths singularities. To confirm the universality of this exotic scaling scenario we also study the generalized contact process with several (symmetric) absorbing states and we support our theory by extensive Monte Carlo simulations. PMID:19518178
16. Transitional flow in thin tubes for space station freedom radiator
NASA Technical Reports Server (NTRS)
Loney, Patrick; Ibrahim, Mounir
1995-01-01
A two dimensional finite volume method is used to predict the film coefficients in the transitional flow region (laminar or turbulent) for the radiator panel tubes. The code used to perform this analysis is CAST (Computer Aided Simulation of Turbulent Flows). The information gathered from this code is then used to augment a Sinda85 model that predicts overall performance of the radiator. A final comparison is drawn between the results generated with a Sinda85 model using the Sinda85 provided transition region heat transfer correlations and the Sinda85 model using the CAST generated data.
17. Federal and state benefits for transition age youth.
PubMed
Altman, Stephanie; O'Connor, Sarah; Anapolsky, Ellyce; Sexton, Laura
2014-01-01
While all children face challenges as they become adults, children with chronic medical conditions or disabilities face unique barriers in their transition to adulthood. Children, especially those who are low income and have special needs, are eligible for a range of supports including income supports, health care coverage, vocational and educational supports. These supports are critical to sound health because they ensure access to necessary medical services, while also offsetting the social determinants that negatively affect health. Unfortunately, as children transition into adulthood, eligibility for these benefits can change abruptly or even end entirely. If medical providers have a better understanding of five transition key dates, they can positively impact their patients' health by ensuring continuous coverage through the transition to adulthood. The key dates are as follows: (1) transition services for students with an Individualized Education Program (IEP) must begin by age 16 (in some states such as Illinois, these services must be in place by age 14 1/2); (2) at age 18, eligibility for income supports may change; (3) at age 19, eligibility for Medicaid may change; (4) at graduation, eligibility for educational supports will end unless steps are taken to extend those benefits until age 22; and (5) when individuals prepare to enter the workforce, they will become eligible for vocational rehabilitation services. With an understanding of these key transition dates and how to partner with social services and advocacy organizations on behalf of their patients, medical providers can help to ensure that transition-age patients retain the holistic social services and supports they need to protect their health. PMID:24919940
18. A transition in brain state during propofol-induced unconsciousness.
PubMed
Mukamel, Eran A; Pirondini, Elvira; Babadi, Behtash; Wong, Kin Foon Kevin; Pierce, Eric T; Harrell, P Grace; Walsh, John L; Salazar-Gomez, Andres F; Cash, Sydney S; Eskandar, Emad N; Weiner, Veronica S; Brown, Emery N; Purdon, Patrick L
2014-01-15
Rhythmic oscillations shape cortical dynamics during active behavior, sleep, and general anesthesia. Cross-frequency phase-amplitude coupling is a prominent feature of cortical oscillations, but its role in organizing conscious and unconscious brain states is poorly understood. Using high-density EEG and intracranial electrocorticography during gradual induction of propofol general anesthesia in humans, we discovered a rapid drug-induced transition between distinct states with opposite phase-amplitude coupling and different cortical source distributions. One state occurs during unconsciousness and may be similar to sleep slow oscillations. A second state occurs at the loss or recovery of consciousness and resembles an enhanced slow cortical potential. These results provide objective electrophysiological landmarks of distinct unconscious brain states, and could be used to help improve EEG-based monitoring for general anesthesia. PMID:24431442
19. Phenomena of solid state grain boundaries phase transition in technology
Minaev, Y. A.
2015-03-01
The results of study the phenomenon, discovered by author (1971), of the phase transition of grain boundary by the formation of two-dimensional liquid or quasi-liquid films have been done. The described phenomena of the first order phase transition (two-dimensional melting) at temperatures 0.6 - 0.9 TS0 (of the solid state melting point) is a fundamental property of solid crystalline materials, which has allowed to revise radically scientific representations about a solid state of substance. Using the mathematical tools of the film thermodynamics it has been obtained the generalized equation of Clausius - Clapeyron type for two-dimensional phase transition. The generalized equation has been used for calculating grain boundary phase transition temperature TSf of any metal, which value lies in the range of (0.55…0.86) TS0. Based on these works conclusions the develop strategies for effective forming of coatings (by thermo-chemical processing) on surface layers of functional alloys and hard metals have been made. The short overview of the results of some graded alloys characterization has been done.
20. Phenomena of solid state grain boundaries phase transition in technology
SciTech Connect
Minaev, Y. A.
2015-03-30
The results of study the phenomenon, discovered by author (1971), of the phase transition of grain boundary by the formation of two-dimensional liquid or quasi-liquid films have been done. The described phenomena of the first order phase transition (two-dimensional melting) at temperatures 0.6 – 0.9 T{sub S0} (of the solid state melting point) is a fundamental property of solid crystalline materials, which has allowed to revise radically scientific representations about a solid state of substance. Using the mathematical tools of the film thermodynamics it has been obtained the generalized equation of Clausius - Clapeyron type for two-dimensional phase transition. The generalized equation has been used for calculating grain boundary phase transition temperature T{sub Sf} of any metal, which value lies in the range of (0.55…0.86) T{sub S0}. Based on these works conclusions the develop strategies for effective forming of coatings (by thermo-chemical processing) on surface layers of functional alloys and hard metals have been made. The short overview of the results of some graded alloys characterization has been done.
1. Physiologic Measures of Animal Stress during Transitional States of Consciousness.
PubMed
Meyer, Robert E
2015-01-01
Determination of the humaneness of methods used to produce unconsciousness in animals, whether for anesthesia, euthanasia, humane slaughter, or depopulation, relies on our ability to assess stress, pain, and consciousness within the contexts of method and application. Determining the subjective experience of animals during transitional states of consciousness, however, can be quite difficult; further, loss of consciousness with different agents or methods may occur at substantially different rates. Stress and distress may manifest behaviorally (e.g., overt escape behaviors, approach-avoidance preferences [aversion]) or physiologically (e.g., movement, vocalization, changes in electroencephalographic activity, heart rate, sympathetic nervous system [SNS] activity, hypothalamic-pituitary axis [HPA] activity), such that a one-size-fits-all approach cannot be easily applied to evaluate methods or determine specific species applications. The purpose of this review is to discuss methods of evaluating stress in animals using physiologic methods, with emphasis on the transition between the conscious and unconscious states. PMID:26479382
2. Absorbing State Phase Transition with Competing Quantum and Classical Fluctuations.
PubMed
Marcuzzi, Matteo; Buchhold, Michael; Diehl, Sebastian; Lesanovsky, Igor
2016-06-17
Stochastic processes with absorbing states feature examples of nonequilibrium universal phenomena. While the classical regime has been thoroughly investigated in the past, relatively little is known about the behavior of these nonequilibrium systems in the presence of quantum fluctuations. Here, we theoretically address such a scenario in an open quantum spin model which, in its classical limit, undergoes a directed percolation phase transition. By mapping the problem to a nonequilibrium field theory, we show that the introduction of quantum fluctuations stemming from coherent, rather than statistical, spin flips alters the nature of the transition such that it becomes first order. In the intermediate regime, where classical and quantum dynamics compete on equal terms, we highlight the presence of a bicritical point with universal features different from the directed percolation class in a low dimension. We finally propose how this physics could be explored within gases of interacting atoms excited to Rydberg states. PMID:27367395
3. Absorbing State Phase Transition with Competing Quantum and Classical Fluctuations
Marcuzzi, Matteo; Buchhold, Michael; Diehl, Sebastian; Lesanovsky, Igor
2016-06-01
Stochastic processes with absorbing states feature examples of nonequilibrium universal phenomena. While the classical regime has been thoroughly investigated in the past, relatively little is known about the behavior of these nonequilibrium systems in the presence of quantum fluctuations. Here, we theoretically address such a scenario in an open quantum spin model which, in its classical limit, undergoes a directed percolation phase transition. By mapping the problem to a nonequilibrium field theory, we show that the introduction of quantum fluctuations stemming from coherent, rather than statistical, spin flips alters the nature of the transition such that it becomes first order. In the intermediate regime, where classical and quantum dynamics compete on equal terms, we highlight the presence of a bicritical point with universal features different from the directed percolation class in a low dimension. We finally propose how this physics could be explored within gases of interacting atoms excited to Rydberg states.
4. Transition state geometry in radical hydrogen atom abstraction
Denisov, Evgenii T.; Shestakov, Alexander F.; Denisova, Taisa G.
2012-12-01
The interatomic distances in the transition states of radical hydrogen atom abstraction reactions X•+HY → XH+Y• determined by quantum chemical calculations are systematized and generalized. It is shown that depending on the reaction centre structure, these reactions can be subdivided into classes with the same X...Y interatomic distance in each class. The transition state geometries found by the methods of intersecting parabolas and intersecting Morse curves are also presented. The X...H...Y fragments are almost linear, the hydrogen atom position being determined by the reaction enthalpy. The effects of triplet repulsion, electronegativities and radii of X and Y atoms, the presence of adjoining π-bonds, and steric effects on the X...Y interatomic distances are analyzed and characterized. The bibliography includes 62 references.
5. Optimal Control of Transitions between Nonequilibrium Steady States
PubMed Central
Zulkowski, Patrick R.; Sivak, David A.; DeWeese, Michael R.
2013-01-01
Biological systems fundamentally exist out of equilibrium in order to preserve organized structures and processes. Many changing cellular conditions can be represented as transitions between nonequilibrium steady states, and organisms have an interest in optimizing such transitions. Using the Hatano-Sasa Y-value, we extend a recently developed geometrical framework for determining optimal protocols so that it can be applied to systems driven from nonequilibrium steady states. We calculate and numerically verify optimal protocols for a colloidal particle dragged through solution by a translating optical trap with two controllable parameters. We offer experimental predictions, specifically that optimal protocols are significantly less costly than naive ones. Optimal protocols similar to these may ultimately point to design principles for biological energy transduction systems and guide the design of artificial molecular machines. PMID:24386112
6. Classical codes in quantum state space
Howard, Mark
2015-12-01
We present a construction of Hermitian operators and quantum states labelled by strings from a finite field. The distance between these operators or states is then simply related (typically, proportional) to the Hamming distance between their corresponding strings. This allows a straightforward application of classical coding theory to find arrangements of operators or states with a given distance distribution. Using the simplex or extended Reed-Solomon code in our construction recovers the discrete Wigner function, which has important applications in quantum information theory.
7. Reliable Transition State Searches Integrated with the Growing String Method.
PubMed
Zimmerman, Paul
2013-07-01
The growing string method (GSM) is highly useful for locating reaction paths connecting two molecular intermediates. GSM has often been used in a two-step procedure to locate exact transition states (TS), where GSM creates a quality initial structure for a local TS search. This procedure and others like it, however, do not always converge to the desired transition state because the local search is sensitive to the quality of the initial guess. This article describes an integrated technique for simultaneous reaction path and exact transition state search. This is achieved by implementing an eigenvector following optimization algorithm in internal coordinates with Hessian update techniques. After partial convergence of the string, an exact saddle point search begins under the constraint that the maximized eigenmode of the TS node Hessian has significant overlap with the string tangent near the TS. Subsequent optimization maintains connectivity of the string to the TS as well as locks in the TS direction, all but eliminating the possibility that the local search leads to the wrong TS. To verify the robustness of this approach, reaction paths and TSs are found for a benchmark set of more than 100 elementary reactions. PMID:26583985
8. Fish reintroductions reveal smooth transitions between lake community states.
PubMed
Mittelbach, Gary G; Garcia, Erica A; Taniguchi, Yoshinori
2006-02-01
Whether communities respond smoothly or discontinuously to changing environmental conditions has important consequences for the preservation and restoration of ecosystems. Theory shows that communities may exhibit a variety of responses to environmental change, including abrupt transitions due to the existence of alternate states. However, there have been few opportunities to look for such transitions in nature. Here, we examine the impact of a two-orders-of-magnitude decrease and then increase in planktivore abundance in Wintergreen lake (Michigan, USA), caused by the extinction and reintroduction of two dominant fish species (largemouth bass, Micropterus salmoides, and bluegill, Lepomis macrochirus). Over a 16 + yr period of slow change from high planktivory to low planktivory back to high planktivory, the zooplankton community changed smoothly and predictably between states. In years of low planktivory, the zooplankton assemblage was dominated by a single, large, cladoceran species, Daphnia pulicaria, whereas in years of high planktivory, D. pulicaria disappeared and was replaced by a suite of small-bodied cladocerans. We quantified the multivariate change in zooplankton community dissimilarity and found that community state smoothly tracked changes in planktivore density in both a forward and backward direction. Thus, there was little evidence of discontinuity in this system where transitions are strongly driven by planktivory. PMID:16637356
9. Biosynthetic consequences of multiple sequential post-transition-state bifurcations
Hong, Young Joo; Tantillo, Dean J.
2014-02-01
Selectivity in chemical reactions that form complex molecular architectures from simpler precursors is usually rationalized by comparing competing transition-state structures that lead to different possible products. Herein we describe a system for which a single transition-state structure leads to the formation of many isomeric products via pathways that feature multiple sequential bifurcations. The reaction network described connects the pimar-15-en-8-yl cation to miltiradiene, a tricyclic diterpene natural product, and isomers via cyclizations and/or rearrangements. The results suggest that the selectivity of the reaction is controlled by (post-transition-state) dynamic effects, that is, how the carbocation structure changes in response to the distribution of energy in its vibrational modes. The inherent dynamical effects revealed herein (characterized through quasiclassical direct dynamics calculations using density functional theory) have implications not only for the general principles of selectivity prediction in systems with complex potential energy surfaces, but also for the mechanisms of terpene synthase enzymes and their evolution. These findings redefine the challenges faced by nature in controlling the biosynthesis of complex natural products.
10. Inherent structure versus geometric metric for state space discretization.
PubMed
Liu, Hanzhong; Li, Minghai; Fan, Jue; Huo, Shuanghong
2016-05-30
Inherent structure (IS) and geometry-based clustering methods are commonly used for analyzing molecular dynamics trajectories. ISs are obtained by minimizing the sampled conformations into local minima on potential/effective energy surface. The conformations that are minimized into the same energy basin belong to one cluster. We investigate the influence of the applications of these two methods of trajectory decomposition on our understanding of the thermodynamics and kinetics of alanine tetrapeptide. We find that at the microcluster level, the IS approach and root-mean-square deviation (RMSD)-based clustering method give totally different results. Depending on the local features of energy landscape, the conformations with close RMSDs can be minimized into different minima, while the conformations with large RMSDs could be minimized into the same basin. However, the relaxation timescales calculated based on the transition matrices built from the microclusters are similar. The discrepancy at the microcluster level leads to different macroclusters. Although the dynamic models established through both clustering methods are validated approximately Markovian, the IS approach seems to give a meaningful state space discretization at the macrocluster level in terms of conformational features and kinetics. © 2016 Wiley Periodicals, Inc. PMID:26915811
11. Coherent States of Quantum Free Particle on the Spherical Space
Dehdashti, Shahram; Roknizadeh, Rasoul; Mahdifar, Ali; Chen, Hongsheng
2016-01-01
In this paper, we study the quantum free particle on the spherical space by applying da costa approach for quantum particle on the curved space. We obtain the discrete energy eigenvalues and associated normalized eigenfunctions of the free particle on the sphere. In addition, we introduce the Gazeau-Klauder coherent states of free particle on the sphere. Then, the Gaussian coherent states is defined, which is used to describe the localized particle on the spherical space. Finally, we study the relation between the f-deformed coherent states and Gazeau-Klauder ones for this system.
12. Crossing the dividing surface of transition state theory. III. Once and only once. Selecting reactive trajectories
SciTech Connect
Lorquet, J. C.
2015-09-14
The purpose of the present work is to determine initial conditions that generate reacting, recrossing-free trajectories that cross the conventional dividing surface of transition state theory (i.e., the plane in configuration space passing through a saddle point of the potential energy surface and perpendicular to the reaction coordinate) without ever returning to it. Local analytical equations of motion valid in the neighborhood of this planar surface have been derived as an expansion in Poisson brackets. We show that the mere presence of a saddle point implies that reactivity criteria can be quite simply formulated in terms of elements of this series, irrespective of the shape of the potential energy function. Some of these elements are demonstrated to be equal to a sum of squares and thus to be necessarily positive, which has a profound impact on the dynamics. The method is then applied to a three-dimensional model describing an atom-diatom interaction. A particular relation between initial conditions is shown to generate a bundle of reactive trajectories that form reactive cylinders (or conduits) in phase space. This relation considerably reduces the phase space volume of initial conditions that generate recrossing-free trajectories. Loci in phase space of reactive initial conditions are presented. Reactivity is influenced by symmetry, as shown by a comparative study of collinear and bent transition states. Finally, it is argued that the rules that have been derived to generate reactive trajectories in classical mechanics are also useful to build up a reactive wave packet.
13. Phase space flow of particles in squeezed states
NASA Technical Reports Server (NTRS)
Ceperley, Peter H.
1994-01-01
The manipulation of noise and uncertainty in squeezed states is governed by the wave nature of the quantum mechanical particles in these states. This paper uses a deterministic model of quantum mechanics in which real guiding waves control the flow of localized particles. This model will be used to examine the phase space flow of particles in typical squeezed states.
14. Third Space Strategists: International Students Negotiating the Transition from Pathway Program to Postgraduate Coursework Degree
ERIC Educational Resources Information Center
Benzie, Helen
2015-01-01
Pathway programs exist to prepare students for progression into university degrees but the transition experience for many students may not be as smooth as is suggested by the notion of the pathway. While attending a pathway program and at the beginning of their university degree, students may be in a third space, a liminal space where they engage…
15. A Space for Academic Play: Student Learning Journals as Transitional Writing
ERIC Educational Resources Information Center
Creme, Phyllis
2008-01-01
This article builds on the author's previous research on student learning journals to explore how their use can give students a "space" to engage meaningfully and in their own way with their university work. Drawing on the psychoanalytical concept of transitional space and on notions of narrative, it is argued that the student learning journal can…
16. Public Pedagogy via PostSecret: A Transitional Space Where Private and Public Coincide
ERIC Educational Resources Information Center
Motter, Jennifer L.
2011-01-01
PostSecret (www.postsecret.com) is a transitional space where the in-betweenness of public and private exists. Within this space, peer public pedagogy occurs through critical participatory democratic interactions of community participants. Integrating PostSecret into the art education curriculum can offer the potential for generative knowledge…
17. Solid state neutron dosimeter for space applications
NASA Technical Reports Server (NTRS)
Entine, Gerald; Nagargar, Vivek; Sharif, Daud
1990-01-01
Personnel engaged in space flight are exposed to significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Presently, there exist no compact neutron sensor capable of being integrated in a flight instrument to provide real time measurement of this radiation flux. A proposal was made to construct such an instrument using special PIN silicon diode which has the property of being insensitive to the other forms of ionizing radiation. Studies were performed to determine the design and construction of a better reading system to allow the PIN diode to be read with high precision. The physics of the device was studied, especially with respect to those factors which affect the sensitivity and reproducibility of the neutron response. This information was then used to develop methods to achieve high sensitivity at low neutron doses. The feasibility was shown of enhancing the PIN diode sensitivity to make possible the measurement of the low doses of neutrons encountered in space flights. The new PIN diode will make possible the development of a very compact, accurate, personal neutron dosimeter.
18. On infinite-dimensional state spaces
SciTech Connect
Fritz, Tobias
2013-05-15
It is well known that the canonical commutation relation [x, p]=i can be realized only on an infinite-dimensional Hilbert space. While any finite set of experimental data can also be explained in terms of a finite-dimensional Hilbert space by approximating the commutation relation, Occam's razor prefers the infinite-dimensional model in which [x, p]=i holds on the nose. This reasoning one will necessarily have to make in any approach which tries to detect the infinite-dimensionality. One drawback of using the canonical commutation relation for this purpose is that it has unclear operational meaning. Here, we identify an operationally well-defined context from which an analogous conclusion can be drawn: if two unitary transformations U, V on a quantum system satisfy the relation V{sup -1}U{sup 2}V=U{sup 3}, then finite-dimensionality entails the relation UV{sup -1}UV=V{sup -1}UVU; this implication strongly fails in some infinite-dimensional realizations. This is a result from combinatorial group theory for which we give a new proof. This proof adapts to the consideration of cases where the assumed relation V{sup -1}U{sup 2}V=U{sup 3} holds only up to {epsilon} and then yields a lower bound on the dimension.
19. On infinite-dimensional state spaces
Fritz, Tobias
2013-05-01
It is well known that the canonical commutation relation [x, p] = i can be realized only on an infinite-dimensional Hilbert space. While any finite set of experimental data can also be explained in terms of a finite-dimensional Hilbert space by approximating the commutation relation, Occam's razor prefers the infinite-dimensional model in which [x, p] = i holds on the nose. This reasoning one will necessarily have to make in any approach which tries to detect the infinite-dimensionality. One drawback of using the canonical commutation relation for this purpose is that it has unclear operational meaning. Here, we identify an operationally well-defined context from which an analogous conclusion can be drawn: if two unitary transformations U, V on a quantum system satisfy the relation V-1U2V = U3, then finite-dimensionality entails the relation UV-1UV = V-1UVU; this implication strongly fails in some infinite-dimensional realizations. This is a result from combinatorial group theory for which we give a new proof. This proof adapts to the consideration of cases where the assumed relation V-1U2V = U3 holds only up to ɛ and then yields a lower bound on the dimension.
20. Solid state neutron dosimeter for space applications
Entine, Gerald; Nagargar, Vivek; Sharif, Daud
1990-08-01
Personnel engaged in space flight are exposed to significant flux of high energy neutrons arising from both primary and secondary sources of ionizing radiation. Presently, there exist no compact neutron sensor capable of being integrated in a flight instrument to provide real time measurement of this radiation flux. A proposal was made to construct such an instrument using special PIN silicon diode which has the property of being insensitive to the other forms of ionizing radiation. Studies were performed to determine the design and construction of a better reading system to allow the PIN diode to be read with high precision. The physics of the device was studied, especially with respect to those factors which affect the sensitivity and reproducibility of the neutron response. This information was then used to develop methods to achieve high sensitivity at low neutron doses. The feasibility was shown of enhancing the PIN diode sensitivity to make possible the measurement of the low doses of neutrons encountered in space flights. The new PIN diode will make possible the development of a very compact, accurate, personal neutron dosimeter.
1. California's Transition to the Common Core State Standards: The State's Role in Local Capacity Building
ERIC Educational Resources Information Center
Warren, Paul; Murphy, Patrick
2014-01-01
The Common Core State Standards (CCSS) and the Local Control Funding Formula are introducing major changes to California's K-12 system. Implementation of new curricula and instruction is under way at the district level, but California started its transition relatively late and it has taken a more decentralized approach than most other states.…
2. Challenges for Transitioning Science Knowledge to an Operational Environment for Space Weather
NASA Technical Reports Server (NTRS)
Spann, James
2012-01-01
Effectively transitioning science knowledge to an operational environment relevant to space weather is critical to meet the civilian and defense needs, especially considering how technologies are advancing and present evolving susceptibilities to space weather impacts. The effort to transition scientific knowledge to a useful application is not a research task nor is an operational activity, but an effort that bridges the two. Successful transitioning must be an intentional effort that has a clear goal for all parties and measureable outcome and deliverable. This talk will present proven methodologies that have been demonstrated to be effective for terrestrial weather and disaster relief efforts, and how those methodologies can be applied to space weather transition efforts.
3. Deep Space Habitat Concept of Operations for Transit Mission Phases
NASA Technical Reports Server (NTRS)
Hoffman, Stephen J.
2011-01-01
The National Aeronautics and Space Administration (NASA) has begun evaluating various mission and system components of possible implementations of what the U.S. Human Spaceflight Plans Committee (also known as the Augustine Committee) has named the flexible path (Anon., 2009). As human spaceflight missions expand further into deep space, the duration of these missions increases to the point where a dedicated crew habitat element appears necessary. There are several destinations included in this flexible path a near Earth asteroid (NEA) mission, a Phobos/Deimos (Ph/D) mission, and a Mars surface exploration mission that all include at least a portion of the total mission in which the crew spends significant periods of time (measured in months) in the deep space environment and are thus candidates for a dedicated habitat element. As one facet of a number of studies being conducted by the Human Spaceflight Architecture Team (HAT) a workshop was conducted to consider how best to define and quantify habitable volume for these future deep space missions. One conclusion reached during this workshop was the need for a description of the scope and scale of these missions and the intended uses of a habitat element. A group was set up to prepare a concept of operations document to address this need. This document describes a concept of operations for a habitat element used for these deep space missions. Although it may eventually be determined that there is significant overlap with this concept of operations and that of a habitat destined for use on planetary surfaces, such as the Moon and Mars, no such presumption is made in this document.
4. Simulation of space charge effects and transition crossing in the Fermilab Booster
SciTech Connect
Lucas, P.; MacLachlan, J.
1987-03-01
The longitudinal phase space program ESME, modified for space charge and wall impedance effects, has been used to simulate transition crossing in the Fermilab Booster. The simulations yield results in reasonable quantitative agreement with measured parameters. They further indicate that a transition jump scheme currently under construction will significantly reduce emittance growth, while attempts to alter machine impedance are less obviously beneficial. In addition to presenting results, this paper points out a serious difficulty, related to statistical fluctuations, in the space charge calculation. False indications of emittance growth can appear if care is not taken to minimize this problem.
5. Lagrangian Descriptors of Thermalized Transition States on Time-Varying Energy Surfaces
Craven, Galen T.; Hernandez, Rigoberto
2015-10-01
Thermalized chemical reactions driven under dynamical load are characteristic of activated dynamics for arbitrary nonautonomous systems. Recent generalizations of transition state theory to obtain formally exact rates have required the construction of a time-dependent transition state trajectory. Here, we show that Lagrangian descriptors can be used to obtain this structure directly. By developing a phase space separatrix that is void of recrossings, these constructs allow for the principal criterion in the implementation of modern rate theories to be satisfied. Thus, the reactive flux over a time-varying barrier can be determined without ambiguity in chemical reactions. The generality of the formalism suggests that this approach is applicable to any activated system subjected to arbitrary driving and thermal fluctuations.
6. Lagrangian Descriptors of Thermalized Transition States on Time-Varying Energy Surfaces.
PubMed
Craven, Galen T; Hernandez, Rigoberto
2015-10-01
Thermalized chemical reactions driven under dynamical load are characteristic of activated dynamics for arbitrary nonautonomous systems. Recent generalizations of transition state theory to obtain formally exact rates have required the construction of a time-dependent transition state trajectory. Here, we show that Lagrangian descriptors can be used to obtain this structure directly. By developing a phase space separatrix that is void of recrossings, these constructs allow for the principal criterion in the implementation of modern rate theories to be satisfied. Thus, the reactive flux over a time-varying barrier can be determined without ambiguity in chemical reactions. The generality of the formalism suggests that this approach is applicable to any activated system subjected to arbitrary driving and thermal fluctuations. PMID:26551825
7. Planar homotropenylium cation: a transition state with reversed aromaticity.
PubMed
Gibson, Christopher M; Havenith, Remco W A; Fowler, Patrick W; Jenneskens, Leonardus W
2015-02-01
In contrast to the equilibrium structure of the homoaromatic C(s) homotropenylium cation, C8H9(+) (1), which supports a pinched diatropic ring current, the C(2v) transition state (2) for inversion of the methylene bridge of 1 is antiaromatic and supports a two-lobe paratropic π current, as detected by plotting B3LYP/6-31G** ipsocentric current maps. Participation of the bridge CH bonds is crucial for the change in global character of the current in the transition state, as shown by the quenching of its paratropicity on substitution of H by F. Orbital-based arguments allow rationalization of this transition between homoaromaticity and hyper(conjugative) antiaromaticity. More generally, the hyperconjugative ring current in a family of C(2v) planar-constrained geometries of (CR2)C(N-1)H(N-1)(q) homoannulenes (R = H, F) can be switched from paratropic (antiaromatic) to diatropic (aromatic) by variation of ring size, charge, and bridge substituent. An orbital-based counting rule accounts for these systematic trends. PMID:25526524
8. Anisotropic Magnetoresistance State Space of Permalloy Nanowires with Domain Wall Pinning Geometry
PubMed Central
Corte-León, Héctor; Nabaei, Vahid; Manzin, Alessandra; Fletcher, Jonathan; Krzysteczko, Patryk; Schumacher, Hans W.; Kazakova, Olga
2014-01-01
The domain wall-related change in the anisotropic magnetoresistance in L-shaped permalloy nanowires is measured as a function of the magnitude and orientation of the applied magnetic field. The magnetoresistance curves, compiled into so-called domain wall magnetoresistance state space maps, are used to identify highly reproducible transitions between domain states. Magnetic force microscopy and micromagnetic modelling are correlated with the transport measurements of the devices in order to identify different magnetization states. Analysis allows to determine the optimal working parameters for specific devices, such as the minimal field required to switch magnetization or the most appropriate angle for maximal separation of the pinning/depinning fields. Moreover, the complete state space maps can be used to predict evolution of nanodevices in magnetic field without a need of additional electrical measurements and for repayable initialization of magnetic sensors into a well-specified state. PMID:25116470
9. Symmetry for the nonadiabatic transition in Floquet states
SciTech Connect
Hijii, Keigo; Miyashita, Seiji
2010-01-15
The frequency of the Rabi oscillation driven by a periodic external field varies with the parameters of the external field, e.g., frequency and amplitude, and it becomes zero at some points of the parameters, which is called coherent destruction of tunneling. This phenomenon is understood as a degeneracy of the Floquet quasienergies as a function of the parameters. We prove that the time-reversal symmetry of the external field is a necessary condition of the degeneracy. We demonstrate the gap opening in the quasienergy spectrum in asymmetrically periodically driven systems. Moreover, an adiabatic transition of the Floquet states is demonstrated and analyzed in the analogy to the Landau-Zener transition.
10. Mechanical properties of 4d transition metals in molten state
Singh, Deobrat; Sonvane, Yogesh; Thakor, P. B.
2016-05-01
Mechanical properties of 4d transition metals in molten state have been studied in the present study. We have calculated mechanical properties such as isothermal bulk modulus (B), modulus of rigidity (G), Young's modulus (Y) and Hardness have also been calculated from the elastic part of the Phonon dispersion curve (PDC). To describe the structural information, we have used different structure factor S(q) using Percus-Yevick hard sphere (PYHS) reference systems along with our newly constructed parameter free model potential.To see the influence of exchange and correlation effect on the above said properties of 3d liquid transition metals, we have used Sarkar et al (S)local field correction functions. Present results have been found good in agreement with available experimental data.
11. Mechanical induction of transitions into mesenchymal and amoeboid states
Liphardt, Jan
One of the fundamental mysteries of biology lies in the ability of cells to convert from one phenotype to another in response to external control inputs. We have been studying the Epithelial-to-Mesenchymal Transition (EMT), which allows organized assemblies of epithelial cells to scatter into lone mesenchymal cells. EMT is critical for normal development and wound healing, and may be important for cancer metastasis. I'll present recent data on disorganizing mammary epithelial structures. We have used CRISPR to insert fluorescent tags directly into eight EMT-related genes (such as E-cadherin and Vimentin), which allows us to monitor the dynamics of the transition in real time, subject only to delays imposed by fluorophore folding/maturation times. With this information, we can begin to order events in time (temporal resolution 30 minutes), starting with external signal inputs and proceeding through a secession of intracellular changes of gene expression on the path to the mesenchymal state.
12. Design and Implementation of the Boundary Layer Transition Flight Experiment on Space Shuttle Discovery
NASA Technical Reports Server (NTRS)
Spanos, Theodoros A.; Micklos, Ann
2010-01-01
In an effort to better the understanding of high speed aerodynamics, a series of flight experiments were installed on Space Shuttle Discovery during the STS-119 and STS-128 missions. This experiment, known as the Boundary Layer Transition Flight Experiment (BLTFE), provided the technical community with actual entry flight data from a known height protuberance at Mach numbers at and above Mach 15. Any such data above Mach 15 is irreproducible in a laboratory setting. Years of effort have been invested in obtaining this valuable data, and many obstacles had to be overcome in order to ensure the success of implementing an Orbiter modification. Many Space Shuttle systems were involved in the installation of appropriate components that revealed 'concurrent engineering' was a key integration tool. This allowed the coordination of all various parts and pieces which had to be sequenced appropriately and installed at the right time. Several issues encountered include Orbiter configuration and access, design requirements versus current layout, implementing the modification versus typical processing timelines, and optimizing the engineering design cycles and changes. Open lines of communication within the entire modification team were essential to project success as the team was spread out across the United States, from NASA Kennedy Space Center in Florida, to NASA Johnson Space Center in Texas, to Boeing Huntington Beach, California among others. The forum permits the discussion of processing concerns from the design phase to the implementation phase, which eventually saw the successful flights and data acquisition on STS-119 in March 2009 and on STS-128 in September 2009.
13. Control of State Transitions in Complex and Biophysical Networks
Motter, Adilson; Wells, Daniel; Kath, William
Noise is a fundamental part of intracellular processes. While the response of biological systems to noise has been studied extensively, there has been limited understanding of how to exploit it to induce a desired cell state. Here I will present a scalable, quantitative method based on the Freidlin-Wentzell action to predict and control noise-induced switching between different states in genetic networks that, conveniently, can also control transitions between stable states in the absence of noise. I will discuss applications of this methodology to predict control interventions that can induce lineage changes and to identify new candidate strategies for cancer therapy. This framework offers a systems approach to identifying the key factors for rationally manipulating network dynamics, and should also find use in controlling other classes of complex networks exhibiting multi-stability. Reference: D. K. Wells, W. L. Kath, and A. E. Motter, Phys. Rev. X 5, 031036 (2015). Work funded by CBC, NCI, NIGMS, and NSF.
14. Virtual states introduced for overcoming entropic barriers in conformational space
PubMed Central
Higo, Junichi; Nakamura, Haruki
2012-01-01
Free-energy landscape is an important quantity to study large-scale motions of a biomolecular system because it maps possible pathways for the motions. When the landscape consists of thermodynamically stable states (low-energy basins), which are connected by narrow conformational pathways (i.e., bottlenecks), the narrowness slows the inter-basin round trips in conformational sampling. This results in inaccuracy of free energies for the basins. This difficulty is not cleared out even when an enhanced conformational sampling is fairly performed along a reaction coordinate. In this study, to enhance the inter-basin round trips we introduced a virtual state that covers the narrow pathways. The probability distribution function for the virtual state was controlled based on detailed balance condition for the inter-state transitions (transitions between the real-state basins and the virtual state). To mimic the free-energy landscape of a real biological system, we introduced a simple model where a wall separates two basins and a narrow hole is pierced in the wall to connect the basins. The sampling was done based on Monte Carlo (MC). We examined several hole-sizes and inter-state transition probabilities. For a small hole-size, a small inter-state transition probability produced a sampling efficiency 100 times higher than a conventional MC does. This result goes against ones intuition, because one considers generally that the sampling efficiency increases with increasing the transition probability. The present method is readily applicable to enhanced conformational sampling such as multi-canonical or adaptive umbrella sampling, and extendable to molecular dynamics.
15. The Physics of Imaging with Remote Sensors : Photon State Space & Radiative Transfer
NASA Technical Reports Server (NTRS)
Davis, Anthony B.
2012-01-01
Standard (mono-pixel/steady-source) retrieval methodology is reaching its fundamental limit with access to multi-angle/multi-spectral photo- polarimetry. Next... Two emerging new classes of retrieval algorithm worth nurturing: multi-pixel time-domain Wave-radiometry transition regimes, and more... Cross-fertilization with bio-medical imaging. Physics-based remote sensing: - What is "photon state space?" - What is "radiative transfer?" - Is "the end" in sight? Two wide-open frontiers! center dot Examples (with variations.
16. The role of space telescopes in the characterization of transiting exoplanets
Hatzes, Artie P.
2014-09-01
Characterization studies now have a dominant role in the field of exoplanets. Such studies include the measurement of an exoplanet's bulk density, its brightness temperature and the chemical composition of its atmosphere. The use of space telescopes has played a key part in the characterization of transiting exoplanets. These facilities offer astronomers data of exquisite precision and temporal sampling as well as access to wavelength regions of the electromagnetic spectrum that are inaccessible from the ground. Space missions such as the Hubble Space Telescope, Microvariability and Oscillations of Stars (MOST), Spitzer Space Telescope, Convection, Rotation and Planetary Transits (CoRoT), and Kepler have rapidly advanced our knowledge of the physical properties of exoplanets and have blazed a trail for a series of future space missions that will help us to understand the observed diversity of exoplanets.
17. The role of space telescopes in the characterization of transiting exoplanets.
PubMed
Hatzes, Artie P
2014-09-18
Characterization studies now have a dominant role in the field of exoplanets. Such studies include the measurement of an exoplanet's bulk density, its brightness temperature and the chemical composition of its atmosphere. The use of space telescopes has played a key part in the characterization of transiting exoplanets. These facilities offer astronomers data of exquisite precision and temporal sampling as well as access to wavelength regions of the electromagnetic spectrum that are inaccessible from the ground. Space missions such as the Hubble Space Telescope, Microvariability and Oscillations of Stars (MOST), Spitzer Space Telescope, Convection, Rotation and Planetary Transits (CoRoT), and Kepler have rapidly advanced our knowledge of the physical properties of exoplanets and have blazed a trail for a series of future space missions that will help us to understand the observed diversity of exoplanets. PMID:25230657
18. How to upload a physical quantum state into correlation space
Morimae, Tomoyuki
2011-04-01
19. Solid State Molecular Reactors in Space
Maurette, M.
2011-03-01
Lunar minerals and impact glasses, convert the polyatomic beam of solar wind (SW) ions into a flux of small molecules (e.g., H2, N2, H2O, CO, CO2, CH4, C2H4, C2H6, HCN, metal carbides and deuterides, etc.). They thus behave as "Solid State Molecular Reactors". Moreover, ~100-200 μm size micrometeoroids (μMs) have also been exposed to the SW in the zodiacal cloud, before being captured by the Earth and recovered as Antarctic micrometeorites. They are mostly composed of a PAH-rich hydrous-carbonaceous material, which amplifies their power as molecular reactors. In particular, during the first ~200 Myr of the post-lunar period, about 75% of the μMs have been melted and/or volatilized upon atmospheric entry. The release of their volatile species triggered a cosmic volcanism around the mesopause that ruled the formation of the early Earth's atmosphere and climate. Furthermore, a fraction of the μMs that survive unmelted upon atmospheric entry did settle on the proto-oceans floors. Upon further burial in sediments their constituent PAH-rich kerogen was cracked into abiotic oil, which generated giant oil slicks that fed prebiotic chemistry. Many stars, of all ages and types, are embedded into a secondary debris-disk loaded with ion implanted μMs. Some of them are expelled to the interstellar medium (ISM) where they behave first as "dormant-invisible" molecular reactors, until they became reactivated by various processes to synthesize interstellar molecules. This short paper only focus on some highlights of this research dealing with the synthesis of important interstellar molecules, including the most abundant ones (H2 and CO) and H2O, HCN and PAHs, all involved in prebiotic chemistry.
20. Detecting critical state before phase transition of complex systems by hidden Markov model
Liu, Rui; Chen, Pei; Li, Yongjun; Chen, Luonan
Identifying the critical state or pre-transition state just before the occurrence of a phase transition is a challenging task, because the state of the system may show little apparent change before this critical transition during the gradual parameter variations. Such dynamics of phase transition is generally composed of three stages, i.e., before-transition state, pre-transition state, and after-transition state, which can be considered as three different Markov processes. Thus, based on this dynamical feature, we present a novel computational method, i.e., hidden Markov model (HMM), to detect the switching point of the two Markov processes from the before-transition state (a stationary Markov process) to the pre-transition state (a time-varying Markov process), thereby identifying the pre-transition state or early-warning signals of the phase transition. To validate the effectiveness, we apply this method to detect the signals of the imminent phase transitions of complex systems based on the simulated datasets, and further identify the pre-transition states as well as their critical modules for three real datasets, i.e., the acute lung injury triggered by phosgene inhalation, MCF-7 human breast cancer caused by heregulin, and HCV-induced dysplasia and hepatocellular carcinoma.
1. Green's function approach to edge states in transition metal dichalcogenides
Farmanbar, Mojtaba; Amlaki, Taher; Brocks, Geert
2016-05-01
The semiconducting two-dimensional transition metal dichalcogenides MX 2 show an abundance of one-dimensional metallic edges and grain boundaries. Standard techniques for calculating edge states typically model nanoribbons, and require the use of supercells. In this paper, we formulate a Green's function technique for calculating edge states of (semi-)infinite two-dimensional systems with a single well-defined edge or grain boundary. We express Green's functions in terms of Bloch matrices, constructed from the solutions of a quadratic eigenvalue equation. The technique can be applied to any localized basis representation of the Hamiltonian. Here, we use it to calculate edge states of MX 2 monolayers by means of tight-binding models. Aside from the basic zigzag and armchair edges, we study edges with a more general orientation, structurally modifed edges, and grain boundaries. A simple three-band model captures an important part of the edge electronic structures. An 11-band model comprising all valence orbitals of the M and X atoms is required to obtain all edge states with energies in the MX 2 band gap. Here, states of odd symmetry with respect to a mirror plane through the layer of M atoms have a dangling-bond character, and tend to pin the Fermi level.
2. Two Dimensional State Transition of a Swarming Model
Chuang, Yao-Li; Marthaler, Daniel
2005-03-01
A rotating mill is widely seen in swarming patterns of various species, such as ants, fishes, or daphnia. Levine et al. (2000) proposed an individual based model which produces a pair of co- existing clockwise and counter-clockwise mills on top of each other while a unified rotating mill can be achieved by switching the formula of the self-propulsion to an ensemble average. Without changing its fundamental concepts, we modify the model to include a Rayleigh-type self-driving mechanism, which has a cleaner connection to its continuum limit, i.e., macroscopic description, where analysis can be more efficiently done. By varying parameter values, we find that the modified model goes through a three-stage transition from the co-existing state to the unified state. We also compare the numerical results of the model and of its continuum counterpart.
3. Space Grant and Astronomy Education: The State of Washington's Story
Lutz, J.
2000-12-01
This poster summarizes projects that I have been involved in which utilize NASA Space Grant resources to improve K-12 and undergraduate education at institutions in the State of Washington. Examples I will use include the development of preservice courses for K-12 teachers, inservice workshops for K-12 teachers, minigrants for teachers, support of teacher/scientist partnerships, dissemination of NASA and other resources (curriculum, videos, etc.) to teachers, and support for undergraduate research projects, mentoring and scholarships. I will show how these projects contribute to achieving Washington state and national science standards. Space Grant funding exists in every state and can potentially be accessed by astronomers to carry out education projects that are appropriate to their institution and area of interest. Information will be provided on how to contact Space Grant offices in each state.
4. Chemical potential driven phase transition of black holes in anti-de Sitter space
Galante, Mario; Giribet, Gaston; Goya, Andrés; Oliva, Julio
2015-11-01
Einstein-Maxwell theory conformally coupled to a scalar field in D dimensions may exhibit a phase transition at low temperature whose end point is an asymptotically anti-de Sitter black hole with a scalar field profile that is regular everywhere outside and on the horizon. This provides a tractable model to study the phase transition of hairy black holes in anti-de Sitter space in which the backreaction on the geometry can be solved analytically.
5. Metal-insulator transitions of bulk and domain-wall states in pyrochlore iridates
Ueda, Kentaro
A family of pyrochlore iridates R2Ir2O7 offers an ideal platform to explore intriguing phases such as topological Mott insulator and Weyl semimetal. Here we report transport and spectroscopic studies on the metal-insulator transition (MIT) induced by the modulations of effective electron correlation and magnetic structures, which is finely tuned by external pressure, chemical substitutions (R = Nd1-x Prx and SmyNd1-y) , and magnetic field. A reentrant insulator-metal-insulator transition is observed near the paramagnetic insulator-metal phase boundary reminiscent of a first-order Mott transition for R = SmyNd1-y compounds (y~0.8). The metallic states on the magnetic domain walls (DWs), which are observed for R = Nd in real space as well as in transport properties, is simultaneously turned into the insulating one. These findings imply that the DW electronic state is intimately linked to the bulk states. For the mixed R = Nd1-x Prx compounds, the divergent behavior of resistivity with antiferromagnetic order is significantly suppressed by applying a magnetic field along [001] direction. It is attributed to the phase transition from the antiferromagnetic insulating state to the novel Weyl (semi-)metal state accompanied by the change of magnetic structure. The present study combined with experiment and theory suggests that there are abundant exotic phases with physical parameters such as electron correlation and Ir-5 d magnetic order pattern. Work performed in collaboration with J. Fujioka, B.-J. Yang, C. Terakura, N. Nagaosa, Y. Tokura (University of Tokyo, RIKEN CEMS), J. Shiogai, A. Tsukazaki, S. Nakamura, S. Awaji (Tohoku University). 1This work was supported by JSPS FIRST Program and Grant-in-Aid for Scientific Research (Grants No. 80609488 and No. 24224009).
6. Physiologic Measures of Animal Stress during Transitional States of Consciousness
PubMed Central
Meyer, Robert E.
2015-01-01
Simple Summary The humaneness, and therefore suitability, of any particular agent or method used to produce unconsciousness in animals, whether for anesthesia, euthanasia, humane slaughter, or depopulation, depends on the experience of pain or distress prior to loss of consciousness. Commonly reported physiologic measures of animal stress, including physical movement and vocalization, heart rate and ECG, electroencephalographic activity, and plasma and neuronal stress markers are discussed within this context. Abstract Determination of the humaneness of methods used to produce unconsciousness in animals, whether for anesthesia, euthanasia, humane slaughter, or depopulation, relies on our ability to assess stress, pain, and consciousness within the contexts of method and application. Determining the subjective experience of animals during transitional states of consciousness, however, can be quite difficult; further, loss of consciousness with different agents or methods may occur at substantially different rates. Stress and distress may manifest behaviorally (e.g., overt escape behaviors, approach-avoidance preferences [aversion]) or physiologically (e.g., movement, vocalization, changes in electroencephalographic activity, heart rate, sympathetic nervous system [SNS] activity, hypothalamic-pituitary axis [HPA] activity), such that a one-size-fits-all approach cannot be easily applied to evaluate methods or determine specific species applications. The purpose of this review is to discuss methods of evaluating stress in animals using physiologic methods, with emphasis on the transition between the conscious and unconscious states. PMID:26479382
7. Transition states of magnetization reversal in ferromagnetic nanorings
Chaves-O'Flynn, Gabriel; Kent, Andrew; Stein, Daniel
2008-03-01
Thin ferromagnetic rings are of interest for fundamental studies of magnetization reversal, in part, because they are a rare example of a geometry for which an analytical solution for the rate of thermally induced switching has been determined [1]. The theoretical model predicts the transition state to be either a global magnetization rotation of constant azimuthal angle or a localized fluctuation, denoted the instanton saddle. Numerically we have confirmed that for a range of values of external magnetic field and ring size the instanton saddle is energetically favored [2]. The model takes the annular width to be small compared to the mean radius of the annulus; in which case the main contribution to the magnetization energy comes from the surface magnetostatic energy. We present numerical micromagnetic calculations of the activation energy for thermally induced magnetization reversal for the two different transition states for the case when the annular width is equal in magnitude to the mean radius of the ring. Results of the total and surface magnetostatic energies are compared for different ring sizes. [1] K. Martens, D.L. Stein, A.D. Kent, PRB 73, 054413 (2006) [2] G.D. Chaves-O'Flynn, K. Xiao, D.L. Stein, A. D. Kent, arXiv:0710.2546 (2007)
8. Conformational Transition of Giant DNA in a Confined Space Surrounded by a Phospholipid Membrane
PubMed Central
Kato, Ayako; Shindo, Eri; Sakaue, Takahiro; Tsuji, Akihiko; Yoshikawa, Kenichi
2009-01-01
It has been established that a long DNA molecule exhibits a large discrete conformational change from a coiled state to a highly folded state in aqueous solution, depending on the presence of various condensing agents such as polyamines. In this study, T4 DNA labeled with fluorescent dyes was encapsulated in a cell-sized microdroplet covered with a phospholipid membrane to investigate the conformational behavior of a DNA molecule in such a confined space. Fluorescence microscopy showed that the presence of Mg2+ induced the adsorption of DNA onto the membrane inner-surface of a droplet composed of phosphatidylethanolamine, while no adsorption was observed onto a phosphatidylcholine membrane. Under the presence of spermine (tetravalent amine), DNA had a folded conformation in the bulk solution. However, when these molecules were encapsulated in the microdroplet, DNA adsorbed onto the membrane surface accompanied by unfolding of its structure into an extended coil conformation under high concentrations of Mg2+. In addition, DNA molecules trapped in large droplets tended not to be adsorbed on the membrane, i.e., no conformational transition occurred. A thermodynamic analysis suggests that the translational entropy loss of a DNA molecule that is accompanied by adsorption is a key factor in these phenomena under micrometer-scale confinement. PMID:19751673
9. Observing in space and time the ephemeral nucleation of liquid-to-crystal phase transitions
PubMed Central
Yoo, Byung-Kuk; Kwon, Oh-Hoon; Liu, Haihua; Tang, Jau; Zewail, Ahmed H.
2015-01-01
The phase transition of crystalline ordering is a general phenomenon, but its evolution in space and time requires microscopic probes for visualization. Here we report direct imaging of the transformation of amorphous titanium dioxide nanofilm, from the liquid state, passing through the nucleation step and finally to the ordered crystal phase. Single-pulse transient diffraction profiles at different times provide the structural transformation and the specific degree of crystallinity (η) in the evolution process. It is found that the temporal behaviour of η exhibits unique ‘two-step' dynamics, with a robust ‘plateau' that extends over a microsecond; the rate constants vary by two orders of magnitude. Such behaviour reflects the presence of intermediate structure(s) that are the precursor of the ordered crystal state. Theoretically, we extend the well-known Johnson–Mehl–Avrami–Kolmogorov equation, which describes the isothermal process with a stretched-exponential function, but here over the range of times covering the melt-to-crystal transformation. PMID:26478194
10. Observing in space and time the ephemeral nucleation of liquid-to-crystal phase transitions.
PubMed
Yoo, Byung-Kuk; Kwon, Oh-Hoon; Liu, Haihua; Tang, Jau; Zewail, Ahmed H
2015-01-01
The phase transition of crystalline ordering is a general phenomenon, but its evolution in space and time requires microscopic probes for visualization. Here we report direct imaging of the transformation of amorphous titanium dioxide nanofilm, from the liquid state, passing through the nucleation step and finally to the ordered crystal phase. Single-pulse transient diffraction profiles at different times provide the structural transformation and the specific degree of crystallinity (η) in the evolution process. It is found that the temporal behaviour of η exhibits unique 'two-step' dynamics, with a robust 'plateau' that extends over a microsecond; the rate constants vary by two orders of magnitude. Such behaviour reflects the presence of intermediate structure(s) that are the precursor of the ordered crystal state. Theoretically, we extend the well-known Johnson-Mehl-Avrami-Kolmogorov equation, which describes the isothermal process with a stretched-exponential function, but here over the range of times covering the melt-to-crystal transformation. PMID:26478194
11. Observing in space and time the ephemeral nucleation of liquid-to-crystal phase transitions
Yoo, Byung-Kuk; Kwon, Oh-Hoon; Liu, Haihua; Tang, Jau; Zewail, Ahmed H.
2015-10-01
The phase transition of crystalline ordering is a general phenomenon, but its evolution in space and time requires microscopic probes for visualization. Here we report direct imaging of the transformation of amorphous titanium dioxide nanofilm, from the liquid state, passing through the nucleation step and finally to the ordered crystal phase. Single-pulse transient diffraction profiles at different times provide the structural transformation and the specific degree of crystallinity (η) in the evolution process. It is found that the temporal behaviour of η exhibits unique two-step' dynamics, with a robust plateau' that extends over a microsecond; the rate constants vary by two orders of magnitude. Such behaviour reflects the presence of intermediate structure(s) that are the precursor of the ordered crystal state. Theoretically, we extend the well-known Johnson-Mehl-Avrami-Kolmogorov equation, which describes the isothermal process with a stretched-exponential function, but here over the range of times covering the melt-to-crystal transformation.
12. America's Next Great Ship: Space Launch System Core Stage Transitioning from Design to Manufacturing
NASA Technical Reports Server (NTRS)
Birkenstock, Benjamin; Kauer, Roy
2014-01-01
The Space Launch System (SLS) Program is essential to achieving the Nation's and NASA's goal of human exploration and scientific investigation of the solar system. As a multi-element program with emphasis on safety, affordability, and sustainability, SLS is becoming America's next great ship of exploration. The SLS Core Stage includes avionics, main propulsion system, pressure vessels, thrust vector control, and structures. Boeing manufactures and assembles the SLS core stage at the Michoud Assembly Facility (MAF) in New Orleans, LA, a historical production center for Saturn V and Space Shuttle programs. As the transition from design to manufacturing progresses, the importance of a well-executed manufacturing, assembly, and operation (MA&O) plan is crucial to meeting performance objectives. Boeing employs classic techniques such as critical path analysis and facility requirements definition as well as innovative approaches such as Constraint Based Scheduling (CBS) and Cirtical Chain Project Management (CCPM) theory to provide a comprehensive suite of project management tools to manage the health of the baseline plan on both a macro (overall project) and micro level (factory areas). These tools coordinate data from multiple business systems and provide a robust network to support Material & Capacity Requirements Planning (MRP/CRP) and priorities. Coupled with these tools and a highly skilled workforce, Boeing is orchestrating the parallel buildup of five major sub assemblies throughout the factory. Boeing and NASA are transforming MAF to host state of the art processes, equipment and tooling, the most prominent of which is the Vertical Assembly Center (VAC), the largest weld tool in the world. In concert, a global supply chain is delivering a range of structural elements and component parts necessary to enable an on-time delivery of the integrated Core Stage. SLS is on plan to launch humanity into the next phase of space exploration.
13. Calculating helium atomic excited states in coordinate space
Hall, Shane; Siegel, P. B.
2015-12-01
Two coupled Schrödinger equations are used to calculate excited states of atomic helium. Using product state functions for the two-electron state, the shooting method is used to numerically determine the energies of the allowed singlet and triplet levels. The calculations agree well with the data, and the coordinate-space basis yields Schrödinger equations for helium that are familiar to students who have used similar methods for the hydrogen atom.
14. Transition in the Human Exploration of Space at NASA
NASA Technical Reports Server (NTRS)
Koch, Carla A.; Cabana, Robert
2011-01-01
NASA is taking the next step in human exploration, beyond low Earth orbit. We have been going to low Earth orbit for the past 50 years and are using this experience to work with commercial companies to perform this function. This will free NASA resources to develop the systems necessary to travel to a Near Earth Asteroid, the Moon, Lagrange Points, and eventually Mars. At KSC, we are positioning ourselves to become a multi-user launch complex and everything we are working on is bringing us closer to achieving this goal. A vibrant multi-use spaceport is to the 21st Century what the airport was to the 20th Century - an invaluable transportation hub that supports government needs while promoting economic development and commercial markets beyond Earth's atmosphere. This past year saw the end of Shuttle, but the announcements of NASA's crew module, Orion, and heavy-lift rocket, the SLS, as well as the establishment of the Commercial Crew Program. We have a busy, but very bright future ahead of us and KSC is looking forward to playing an integral part in the next era of human space exploration. The future is SLS, 21st Century Ground Systems Program, and the Commercial Crew Program; and the future is here.
15. Phase transitions of the generalized contact process with two absorbing states.
PubMed
Lee, Man Young; Vojta, Thomas
2010-06-01
We investigate the generalized contact process with two absorbing states in one space dimension by means of large-scale Monte Carlo simulations. Treating the creation rate of active sites between inactive domains as an independent parameter leads to a rich phase diagram. In addition to the conventional active and inactive phases we find a parameter region where the simple contact process is inactive, but an infinitesimal creation rate at the boundary between inactive domains is sufficient to take the system into the active phase. Thus, the generalized contact process has two different phase transition lines. The point separating them shares some characteristics with a multicritical point. We also study in detail the critical behaviors of these transitions and their universality. PMID:20866399
16. Bethe-Salpeter bound-state structure in Minkowski space
Gutierrez, C.; Gigante, V.; Frederico, T.; Salmè, G.; Viviani, M.; Tomio, Lauro
2016-08-01
The quantitative investigation of the scalar Bethe-Salpeter equation in Minkowski space, within the ladder-approximation framework, is extended to include the excited states. This study has been carried out for an interacting system composed by two massive bosons exchanging a massive scalar, by adopting (i) the Nakanishi integral representation of the Bethe-Salpeter amplitude, and (ii) the formally exact projection onto the null plane. Our analysis, on one hand, confirms the reliability of the method already applied to the ground state and, on the other one, extends the investigation from the valence distribution in momentum space to the corresponding quantity in the impact-parameter space, pointing out some relevant features, like (i) the equivalence between Minkowski and Euclidean transverse-momentum amplitudes, and (ii) the leading exponential fall-off of the valence wave function in the impact-parameter space.
17. Ongoing Space Nuclear Systems Development in the United States
SciTech Connect
S. Bragg-Sitton; J. Werner; S. Johnson; Michael G. Houts; Donald T. Palac; Lee S. Mason; David I. Poston; A. Lou Qualls
2011-10-01
Reliable, long-life power systems are required for ambitious space exploration missions. Nuclear power and propulsion options can enable a bold, new set of missions and introduce propulsion capabilities to achieve access to science destinations that are not possible with more conventional systems. Space nuclear power options can be divided into three main categories: radioisotope power for heating or low power applications; fission power systems for non-terrestrial surface application or for spacecraft power; and fission power systems for electric propulsion or direct thermal propulsion. Each of these areas has been investigated in the United States since the 1950s, achieving various stages of development. While some nuclear systems have achieved flight deployment, others continue to be researched today. This paper will provide a brief overview of historical space nuclear programs in the U.S. and will provide a summary of the ongoing space nuclear systems research, development, and deployment in the United States.
18. Transition between locked and running states for dimer motion induced by periodic external driving.
PubMed
Hennig, D; Martens, S; Fugmann, S
2008-07-01
We study the motion of a dimer in a one-dimensional spatially periodic washboard potential. The tilt of the latter is time-periodically modulated by an ac field. We focus interest on the detrapping of the (static) ground state solution of the dimer caused by the ac field. Moreover, we demonstrate that slow tilt modulations not only induce a trapping-detrapping transition but drive the dimer dynamics into a regime of transient long-range running states. Most strikingly, the motion proceeds then unidirectionally, so that the dimer covers huge distances regardless of the fact that the bias force in the driven system vanishes on the average. We elucidate the underlying dynamics in phase space and associate long-lasting running states with the motion in ballistic channels occurring due to stickiness to invariant tori. PMID:18763916
19. Space Sciences Education and Outreach Project of Moscow State University
Krasotkin, S.
2006-11-01
[email protected] The space sciences education and outreach project was initiated at Moscow State University in order to incorporate modern space research into the curriculum popularize the basics of space physics, and enhance public interest in space exploration. On 20 January 2005 the first Russian University Satellite “Universitetskiy-Tatyana” was launched into circular polar orbit (inclination 83 deg., altitude 940-980 km). The onboard scientific complex “Tatyana“, as well as the mission control and information receiving centre, was designed and developed at Moscow State University. The scientific programme of the mission includes measurements of space radiation in different energy channels and Earth UV luminosity and lightning. The current education programme consists of basic multimedia lectures “Life of the Earth in the Solar Atmosphere” and computerized practice exercises “Space Practice” (based on the quasi-real-time data obtained from “Universitetskiy-Tatyana” satellite and other Internet resources). A multimedia lectures LIFE OF EARTH IN THE SOLAR ATMOSPHERE containing the basic information and demonstrations of heliophysics (including Sun structure and solar activity, heliosphere and geophysics, solar-terrestrial connections and solar influence on the Earth’s life) was created for upper high-school and junior university students. For the upper-university students there a dozen special computerized hands-on exercises were created based on the experimental quasi-real-time data obtained from our satellites. Students specializing in space physics from a few Russian universities are involved in scientific work. Educational materials focus on upper high school, middle university and special level for space physics students. Moscow State University is now extending its space science education programme by creating multimedia lectures on remote sensing, space factors and materials study, satellite design and development, etc. The space
20. State-Space Algorithms for Estimating Spike Rate Functions
PubMed Central
Smith, Anne C.; Scalon, Joao D.; Wirth, Sylvia; Yanike, Marianna; Suzuki, Wendy A.; Brown, Emery N.
2010-01-01
The accurate characterization of spike firing rates including the determination of when changes in activity occur is a fundamental issue in the analysis of neurophysiological data. Here we describe a state-space model for estimating the spike rate function that provides a maximum likelihood estimate of the spike rate, model goodness-of-fit assessments, as well as confidence intervals for the spike rate function and any other associated quantities of interest. Using simulated spike data, we first compare the performance of the state-space approach with that of Bayesian adaptive regression splines (BARS) and a simple cubic spline smoothing algorithm. We show that the state-space model is computationally efficient and comparable with other spline approaches. Our results suggest both a theoretically sound and practical approach for estimating spike rate functions that is applicable to a wide range of neurophysiological data. PMID:19911062
1. A MECHANISM FOR HYSTERESIS IN BLACK HOLE BINARY STATE TRANSITIONS
SciTech Connect
Begelman, Mitchell C.; Armitage, Philip J.
2014-02-20
We suggest that the hysteretic cycle of black hole state transitions arises from two established properties of accretion disks: the increase in turbulent stress in disks threaded by a net magnetic field and the ability of thick (but not thin) disks to advect such a field radially. During quiescence, magnetic field loops are generated by the magnetorotational instability at the interface between the inner hot flow and outer thin disk. Vertical flux is advected into and accumulates stochastically within the inner flow, where it stimulates the turbulence so that α ∼ 1. The transition to a geometrically thin inner disk occurs when L ∼ α{sup 2} L {sub Edd} ∼ L {sub Edd}, and the first ''thin'' disk to form is itself moderately thick, strongly magnetized, and able to advect field inward. These properties favor episodic jet production. As the accretion rate declines magnetic flux escapes, α decreases to α ∼ 0.01-0.1, and a hot inner flow is not re-established until L << L {sub Edd}. We discuss possible observational consequences of our scenario.
2. A new vacuum state in de Sitter space
Pfautsch, Jonathan D.
1982-11-01
We present a new vacuum state which can be defined in a region of de Sitter space. This region corresponds to a K=-1 Robertson-Walker coordinatization of de Sitter space. The renormalized expectation value of the stress tensor for the conformally invariant massless scalar field in this vacuum is evaluated, and is found to differ from the corresponding result in the usual de Sitter-invariant vacuum by the absence of a pure radiation term. We also indicate that this can be accounted for by regarding the de Sitter-invariant vacuum as a thermal state relative to the new vacuum.
3. Shell transitions between metastable states of Yukawa balls
SciTech Connect
Kaeding, S.; Melzer, A.; Block, D.; Piel, A.; Kaehlert, H.; Ludwig, P.; Bonitz, M.
2008-07-15
Spherical dust clusters composed of several concentric shells are experimentally investigated with particular interest on transitions between different configurations and transitions of particles between different shells. Transitions between different ground and metastable configurations are frequently observed. The experimental analysis allows us to derive the energy differences of different configurations from particles traveling between shells. The observed transitions and transition probabilities are compared to molecular dynamics simulations.
4. Estimating state-transition probabilities for unobservable states using capture-recapture/resighting data
USGS Publications Warehouse
Kendall, W.L.; Nichols, J.D.
2002-01-01
Temporary emigration was identified some time ago as causing potential problems in capture-recapture studies, and in the last five years approaches have been developed for dealing with special cases of this general problem. Temporary emigration can be viewed more generally as involving transitions to and from an unobservable state, and frequently the state itself is one of biological interest (e.g., 'nonbreeder'). Development of models that permit estimation of relevant parameters in the presence of an unobservable state requires either extra information (e.g., as supplied by Pollock's robust design) or the following classes of model constraints: reducing the order of Markovian transition probabilities, imposing a degree of determinism on transition probabilities, removing state specificity of survival probabilities, and imposing temporal constancy of parameters. The objective of the work described in this paper is to investigate estimability of model parameters under a variety of models that include an unobservable state. Beginning with a very general model and no extra information, we used numerical methods to systematically investigate the use of ancillary information and constraints to yield models that are useful for estimation. The result is a catalog of models for which estimation is possible. An example analysis of sea turtle capture-recapture data under two different models showed similar point estimates but increased precision for the model that incorporated ancillary data (the robust design) when compared to the model with deterministic transitions only. This comparison and the results of our numerical investigation of model structures lead to design suggestions for capture-recapture studies in the presence of an unobservable state.
5. Formation of metastable excited states during sputtering of transition metals
SciTech Connect
Wucher, A.; Sroubek, Z.
1997-01-01
We propose a simple model which treats the formation of metastable excited neutral atoms during sputtering of a transition metal as a two step process. First, the energy deposited into the electronic system of the solid by electronic energy losses of all moving particles in the collision cascade is considered to lead to a locally altered equilibrium electronic state of the solid. It is found that this step is dominated by collective interaction with the conduction band electrons rather than by electron promotion in binary atom-atom collisions. Second, sputtered excited atoms are assumed to be formed by resonant neutralization of excited ions (reflecting the altered equilibrium state) while crossing the surface. It is shown that this model explains the total as well as the velocity dependent excitation probability observed in recent experiments on sputtered neutral silver atoms, which cannot be understood in terms of existing theories describing the formation of excited states in sputtering. {copyright} {ital 1996} {ital The American Physical Society}
6. Test of the Chevallier-Polarski-Linder parametrization for rapid dark energy equation of state transitions
SciTech Connect
Linden, Sebastian; Virey, Jean-Marc
2008-07-15
We test the robustness and flexibility of the Chevallier-Polarski-Linder (CPL) parametrization of the dark energy equation of state w(z)=w{sub 0}+w{sub a}(z/1+z) in recovering a four-parameter steplike fiducial model. We constrain the parameter space region of the underlying fiducial model where the CPL parametrization offers a reliable reconstruction. It turns out that non-negligible biases leak into the results for recent (z<2.5) rapid transitions, but that CPL yields a good reconstruction in all other cases. The presented analysis is performed with supernova Ia data as forecasted for a space mission like SNAP/JDEM, combined with future expectations for the cosmic microwave background shift parameter R and the baryonic acoustic oscillation parameter A.
7. Efficient computations of quantum canonical Gibbs state in phase space
Bondar, Denys I.; Campos, Andre G.; Cabrera, Renan; Rabitz, Herschel A.
2016-06-01
The Gibbs canonical state, as a maximum entropy density matrix, represents a quantum system in equilibrium with a thermostat. This state plays an essential role in thermodynamics and serves as the initial condition for nonequilibrium dynamical simulations. We solve a long standing problem for computing the Gibbs state Wigner function with nearly machine accuracy by solving the Bloch equation directly in the phase space. Furthermore, the algorithms are provided yielding high quality Wigner distributions for pure stationary states as well as for Thomas-Fermi and Bose-Einstein distributions. The developed numerical methods furnish a long-sought efficient computation framework for nonequilibrium quantum simulations directly in the Wigner representation.
8. Co-operativity in a nanocrystalline solid-state transition
White, Sarah L.; Smith, Jeremy G.; Behl, Mayank; Jain, Prashant K.
2013-12-01
Co-operativity is a remarkable phenomenon mostly seen in biology, where initial reaction events significantly alter the propensity of subsequent reaction events, giving rise to a nonlinear tightly regulated synergistic response. Here we have found unique evidence of atomic level co-operativity in an inorganic material. A thousand-atom nanocrystal (NC) of the inorganic solid cadmium selenide exhibits strong positive co-operativity in its reaction with copper ions. A NC doped with a few copper impurities becomes highly prone to be doped even further, driving an abrupt transition of the entire NC to the copper selenide phase, as manifested by a strongly sigmoidal response in optical spectroscopy and electron diffraction measurements. The examples presented here suggest that cooperative phenomena may have an important role in the solid state, especially in the nucleation of new chemical phases, crystal growth, and other materials’ transformations.
9. Co-operativity in a nanocrystalline solid-state transition.
PubMed
White, Sarah L; Smith, Jeremy G; Behl, Mayank; Jain, Prashant K
2013-01-01
Co-operativity is a remarkable phenomenon mostly seen in biology, where initial reaction events significantly alter the propensity of subsequent reaction events, giving rise to a nonlinear tightly regulated synergistic response. Here we have found unique evidence of atomic level co-operativity in an inorganic material. A thousand-atom nanocrystal (NC) of the inorganic solid cadmium selenide exhibits strong positive co-operativity in its reaction with copper ions. A NC doped with a few copper impurities becomes highly prone to be doped even further, driving an abrupt transition of the entire NC to the copper selenide phase, as manifested by a strongly sigmoidal response in optical spectroscopy and electron diffraction measurements. The examples presented here suggest that cooperative phenomena may have an important role in the solid state, especially in the nucleation of new chemical phases, crystal growth, and other materials' transformations. PMID:24335761
10. State transitions and decoherence in the avian compass
Poonia, Vishvendra Singh; Saha, Dipankar; Ganguly, Swaroop
2015-05-01
The radical pair model has been successful in explaining behavioral characteristics of the geomagnetic compass believed to underlie the navigation capability of certain avian species. In this study, the spin dynamics of the radical pair model and decoherence therein are interpreted from a microscopic state transition point of view. This helps to elucidate the interplay between the hyperfine and Zeeman interactions that enables the avian compass and clarify the distinctive effects of nuclear and environmental decoherence on it. Three regimes have been identified for the strength of the hyperfine interaction with respect to that of the geomagnetic Zeeman. It is found that the compass is likely to function in the large hyperfine interaction regime. Using a quantum information theoretic quantifier of coherence, we find that nuclear decoherence induces new structure in the spin dynamics for intermediate hyperfine interaction strength. On the other hand, environmental decoherence—modeled by two different noise models—seems to disrupt the compass action.
11. Optimizing transition states via kernel-based machine learning.
PubMed
Pozun, Zachary D; Hansen, Katja; Sheppard, Daniel; Rupp, Matthias; Müller, Klaus-Robert; Henkelman, Graeme
2012-05-01
We present a method for optimizing transition state theory dividing surfaces with support vector machines. The resulting dividing surfaces require no a priori information or intuition about reaction mechanisms. To generate optimal dividing surfaces, we apply a cycle of machine-learning and refinement of the surface by molecular dynamics sampling. We demonstrate that the machine-learned surfaces contain the relevant low-energy saddle points. The mechanisms of reactions may be extracted from the machine-learned surfaces in order to identify unexpected chemically relevant processes. Furthermore, we show that the machine-learned surfaces significantly increase the transmission coefficient for an adatom exchange involving many coupled degrees of freedom on a (100) surface when compared to a distance-based dividing surface. PMID:22583204
12. State transitions and decoherence in the avian compass.
PubMed
Poonia, Vishvendra Singh; Saha, Dipankar; Ganguly, Swaroop
2015-05-01
The radical pair model has been successful in explaining behavioral characteristics of the geomagnetic compass believed to underlie the navigation capability of certain avian species. In this study, the spin dynamics of the radical pair model and decoherence therein are interpreted from a microscopic state transition point of view. This helps to elucidate the interplay between the hyperfine and Zeeman interactions that enables the avian compass and clarify the distinctive effects of nuclear and environmental decoherence on it. Three regimes have been identified for the strength of the hyperfine interaction with respect to that of the geomagnetic Zeeman. It is found that the compass is likely to function in the large hyperfine interaction regime. Using a quantum information theoretic quantifier of coherence, we find that nuclear decoherence induces new structure in the spin dynamics for intermediate hyperfine interaction strength. On the other hand, environmental decoherence-modeled by two different noise models-seems to disrupt the compass action. PMID:26066201
13. Comparison of double-ended transition state search methods
Koslover, Elena F.; Wales, David J.
2007-10-01
While a variety of double-ended transition state search methods have been developed, their relative performance in characterizing complex multistep pathways between structurally disparate molecular conformations remains unclear. Three such methods (doubly-nudged elastic band, a string method, and a growing string method) are compared for a series of benchmarks ranging from permutational isomerizations of the seven-atom Lennard-Jones cluster (LJ7) to highly cooperative LJ38 and LJ75 rearrangements, and the folding pathways of two peptides. A database of short paths between LJ13 local minima is used to explore the effects of parameters and suggest reasonable default values. Each double-ended method was employed within the framework of a missing connection network flow algorithm to construct more complicated multistep pathways. We find that in our implementation none of the three methods definitively outperforms the others, and that their relative effectiveness is strongly system and parameter dependent.
14. Comparison of double-ended transition state search methods.
PubMed
Koslover, Elena F; Wales, David J
2007-10-01
While a variety of double-ended transition state search methods have been developed, their relative performance in characterizing complex multistep pathways between structurally disparate molecular conformations remains unclear. Three such methods (doubly-nudged elastic band, a string method, and a growing string method) are compared for a series of benchmarks ranging from permutational isomerizations of the seven-atom Lennard-Jones cluster (LJ(7)) to highly cooperative LJ(38) and LJ(75) rearrangements, and the folding pathways of two peptides. A database of short paths between LJ(13) local minima is used to explore the effects of parameters and suggest reasonable default values. Each double-ended method was employed within the framework of a missing connection network flow algorithm to construct more complicated multistep pathways. We find that in our implementation none of the three methods definitively outperforms the others, and that their relative effectiveness is strongly system and parameter dependent. PMID:17919006
15. The 2004 Transit of Venus as a Space Science Education Opportunity
Odenwald, S.; Mayo, L.; Vondrak, R.; Thieman, J.; Hawkins, I.; Schultz, G.
2003-12-01
We will present some of the programs and activities that NASA and its missions are preparing in order to support public and K12 education in space science and astronomy using the 2004 transit of Venus as a focal event. The upcoming transit of Venus on June 8 offers a unique opportunity to educate students and the general public about the scale of the solar system and the universe, as well as basic issues in comparative planetology. NASA's Sun-Earth Connection Education Forum is offering a number of programs to take advantage of this rare event. Among these are a live web cast from Spain of the entire transit, a series of radio and TV programs directed at students and the general public, a web cast describing extra-solar planet searches using the transit geometry, and archived observations produced by public observatories and student-operated solar viewers. The NASA/OSS Education Forums will also partner with science museums, planetaria and teachers across the country to bring the transit of Venus 'down to Earth'. In addition to offering enrichment activities in mathematics and space science, we also describe collaborations that have yielded unique historical resources including online archives of newspaper articles from the 1874 and 1882 transits. In addition, in collaboration with the Library of Congress Music Division, we have supported a modern re-orchestration of John Philip Sousa's Transit of Venus March which has not been performed since 1883. We anticipate that the transit of Venus will be a significant event of considerable public interest and curiosity, if the newspaper headlines from the transit seen in 1882 are any indication.
16. Transition from ring to beam arc distributions of water ions near the Space Shuttle orbiter
NASA Technical Reports Server (NTRS)
Cairns, Iver H.
1990-01-01
The distribution function of water ions produced near the Space Shuttle by charge exchange between ionospheric oxygen ions and outgassed water molecules is studied. The transition from a ring to a beam arc distribution function is described. The number density of water ions is found to increase monotonically with decreasing distance from the Shuttle.
17. Transition: Life-Span and Life-Space Considerations for Empowerment.
ERIC Educational Resources Information Center
Szymanski, Edna Mora
1994-01-01
This article integrates literature from counseling, rehabilitation, multicultural education, and special education to explain the importance of life-span considerations, including the preschool and early school years, and the life-space factors of family, culture, and community. Principles for transition interventions which promote empowerment are…
18. The Transitional Space of History: Reflections on the Play of Roger Simon's Remembrance Pedagogy
ERIC Educational Resources Information Center
Farley, Lisa
2014-01-01
This paper reads Roger Simon's concept of "transactional memory" in relationship to D. W. Winnicott's theory of "transitional space" to examine the emotional dimensions of making historical significance. Drawing on a personal memory of archival study with Simon, I suggest that his attention to the ethical qualities of…
19. Predicting Boundary-Layer Transition on Space-Shuttle Re-Entry
NASA Technical Reports Server (NTRS)
Berry, Scott; Horvath, Tom; Merski, Ron; Liechty, Derek; Greene, Frank; Bibb, Karen; Buck, Greg; Hamilton, Harris; Weilmuenster, Jim; Campbell, Chuck; Bouslog, Stan; Kirk, Ben; Bourland, Garry; Cassady, Amy; Anderson, Brian; Reda, Dan; Reuther, James; Kinder, Gerry; Chao, Dennis; Hyatt, Jay; Barnwell, Maria; Wang, K. C.; Schneider, Steve
2008-01-01
The BLT Prediction Tool ("BLT" signifies "Boundary Layer Transition") is provided as part of the Damage Assessment Team analysis package, which is utilized for analyzing local aerothermodynamics environments of damaged or repaired space-shuttle thermal protection tiles. Such analyses are helpful in deciding whether to repair launch-induced damage before re-entering the terrestrial atmosphere.
20. Outline of a transition-state hydrogen-bond theory
Gilli, Paola; Bertolasi, Valerio; Pretto, Loretta; Gilli, Gastone
2006-06-01
Though the H-bond is well characterized as a D-H⋯:A three-center-four-electron interaction, the formulation of a general H-bond theory has turned out to be a rather formidable problem because of the extreme variability of the bonds formed (for instance, O-H⋯O energies range from 0.1 to 31 kcal mol -1). This paper surveys our previous contributions to the problem, including: (a) the H-bond chemical leitmotifs (CLs), showing that there are only four classes of strong H-bonds and one of moderately strong ones; (b) the PA/pK a equalization principle , showing that the four CLs forming strong H-bonds are actually molecular devices apt to equalize the acid-base properties (PA or p Ka) of the H-bond donor and acceptor groups; (c) the driving variable of the H-bond strength, which remains so identified as the difference Δp Ka=p KAH(D-H)-p KBH(A-H +) or, alternatively, ΔPA=PA(D -)-PA(A); and, in particular, (d) the transition-state H-bond theory (TSHBT), which interprets the H-bond as a stationary point along the complete proton transfer pathway going from D-H⋯A to D⋯H-A via the D⋯H⋯A transition state. TSHBT is verified in connection with a series of seven 1-(X-phenylazo)-2-naphthols, a class of compounds forming a strong intramolecular resonance-assisted H-bond (RAHB), which is switched from N-H⋯O to N⋯H-O by the decreasing electron-withdrawing properties of the substituent X. The system is studied in terms of: (i) variable-temperature X-ray crystallography; (ii) DFT emulation of stationary points and full PT pathways; (iii) Marcus rate-equilibrium analysis correlated with substituent LFER Hammett parameters.
1. Experience Transitioning Models and Data at the NOAA Space Weather Prediction Center
Berger, Thomas
2016-07-01
The NOAA Space Weather Prediction Center has a long history of transitioning research data and models into operations and with the validation activities required. The first stage in this process involves demonstrating that the capability has sufficient value to customers to justify the cost needed to transition it and to run it continuously and reliably in operations. Once the overall value is demonstrated, a substantial effort is then required to develop the operational software from the research codes. The next stage is to implement and test the software and product generation on the operational computers. Finally, effort must be devoted to establishing long-term measures of performance, maintaining the software, and working with forecasters, customers, and researchers to improve over time the operational capabilities. This multi-stage process of identifying, transitioning, and improving operational space weather capabilities will be discussed using recent examples. Plans for future activities will also be described.
2. Multi-state succession in wetlands: a novel use of state and transition models
USGS Publications Warehouse
Zweig, Christa L.; Kitchens, Wiley M.
2009-01-01
The complexity of ecosystems and mechanisms of succession are often simplified by linear and mathematical models used to understand and predict system behavior. Such models often do not incorporate multivariate, nonlinear feedbacks in pattern and process that include multiple scales of organization inherent within real-world systems. Wetlands are ecosystems with unique, nonlinear patterns of succession due to the regular, but often inconstant, presence of water on the landscape. We develop a general, nonspatial state and transition (S and T) succession conceptual model for wetlands and apply the general framework by creating annotated succession/management models and hypotheses for use in impact analysis on a portion of an imperiled wetland. The S and T models for our study area, Water Conservation Area 3A South (WCA3), Florida, USA, included hydrologic and peat depth values from multivariate analyses and classification and regression trees. We used the freeware Vegetation Dynamics Development Tool as an exploratory application to evaluate our S and T models with different management actions (equal chance [a control condition], deeper conditions, dry conditions, and increased hydrologic range) for three communities: slough, sawgrass (Cladium jamaicense), and wet prairie. Deeper conditions and increased hydrologic range behaved similarly, with the transition of community states to deeper states, particularly for sawgrass and slough. Hydrology is the primary mechanism for multi-state transitions within our study period, and we show both an immediate and lagged effect on vegetation, depending on community state. We consider these S and T succession models as a fraction of the framework for the Everglades. They are hypotheses for use in adaptive management, represent the community response to hydrology, and illustrate which aspects of hydrologic variability are important to community structure. We intend for these models to act as a foundation for further restoration
3. Multi-state succession in wetlands: a novel use of state and transition models.
PubMed
Zweig, C L; Kitchens, W M
2009-07-01
The complexity of ecosystems and mechanisms of succession are often simplified by linear and mathematical models used to understand and predict system behavior. Such models often do not incorporate multivariate, nonlinear feedbacks in pattern and process that include multiple scales of organization inherent within real-world systems. Wetlands are ecosystems with unique, nonlinear patterns of succession due to the regular, but often inconstant, presence of water on the landscape. We develop a general, nonspatial state and transition (S and T) succession conceptual model for wetlands and apply the general framework by creating annotated succession/management models and hypotheses for use in impact analysis on a portion of an imperiled wetland. The S and T models for our study area, Water Conservation Area 3A South (WCA3), Florida, U.S.A., included hydrologic and peat depth values from multivariate analyses and classification and regression trees. We used the freeware Vegetation Dynamics Development Tool as an exploratory application to evaluate our S and T models with different management actions (equal chance [a control condition], deeper conditions, dry conditions, and increased hydrologic range) for three communities: slough, sawgrass (Cladium jamaicense), and wet prairie. Deeper conditions and increased hydrologic range behaved similarly, with the transition of community states to deeper states, particularly for sawgrass and slough. Hydrology is the primary mechanism for multi-state transitions within our study period, and we show both an immediate and lagged effect on vegetation, depending on community state. We consider these S and T succession models as a fraction of the framework for the Everglades. They are hypotheses for use in adaptive management, represent the community response to hydrology, and illustrate which aspects of hydrologic variability are important to community structure. We intend for these models to act as a foundation for further
4. MOST SPACE TELESCOPE PHOTOMETRY OF THE 2010 JANUARY TRANSIT OF EXTRASOLAR PLANET HD80606b
SciTech Connect
Roberts, Jessica E.; Barnes, Jason W.; Rowe, Jason F.
2013-01-01
We present observations of the full 2010 January transit of HD80606b from the Canadian microsatellite, Microvariability and Oscillations of Stars. By employing a space-based telescope, we monitor the entire transit, thus limiting systematic errors that result from ground observations. We determine measurements for the planetary radius (R{sub p} = 0.987 {+-} 0.061 R {sub Jup}) and inclination (i = 89. Degree-Sign 283 {+-} 0.024) by constraining our fits with the observed parameters of different groups. Our measured mid-transit time of 2455210.6449 {+-} 0.0034 HJD is consistent with the 2010 Spitzer results and is 20 minutes earlier than predicted by groups who observed the 2009 June transit.
5. Conformational transition in signal transduction: metastable states and transition pathways in the activation of a signaling protein.
PubMed
Banerjee, Rahul; Yan, Honggao; Cukier, Robert I
2015-06-01
Signal transduction is of vital importance to the growth and adaptation of living organisms. The key to understand mechanisms of biological signal transduction is elucidation of the conformational dynamics of its signaling proteins, as the activation of a signaling protein is fundamentally a process of conformational transition from an inactive to an active state. A predominant form of signal transduction for bacterial sensing of environmental changes in the wild or inside their hosts is a variety of two-component systems, in which the conformational transition of a response regulator (RR) from an inactive to an active state initiates responses to the environmental changes. Here, RR activation has been investigated using RR468 as a model system by extensive unbiased all-atom molecular dynamics (MD) simulations in explicit solvent, starting from snapshots along a targeted MD trajectory that covers the conformational transition. Markov state modeling, transition path theory, and geometric analyses of the wealth of the MD data have provided a comprehensive description of the RR activation. It involves a network of metastable states, with one metastable state essentially the same as the inactive state and another very similar to the active state that are connected via a small set of intermediates. Five major pathways account for >75% of the fluxes of the conformational transition from the inactive to the active-like state. The thermodynamic stability of the states and the activation barriers between states are found, to identify rate-limiting steps. The conformal transition is initiated predominantly by movements of the β3α3 loop, followed by movements of the β4α4-loop and neighboring α4 helix region, and capped by additional movements of the β3α3 loop. A number of transient hydrophobic and hydrogen bond interactions are revealed, and they may be important for the conformational transition. PMID:25945797
6. Zero-momentum coupling induced transitions of ground states in Rashba spin-orbit coupled Bose-Einstein condensates
Jin, Jingjing; Zhang, Suying; Han, Wei
2014-06-01
We investigate the transitions of ground states induced by zero momentum (ZM) coupling in pseudospin-1/2 Rashba spin-orbit coupled Bose-Einstein condensates confined in a harmonic trap. In a weak harmonic trap, the condensate presents a plane wave (PW) state, a stripe state or a spin polarized ZM state, and the particle distribution of the stripe state is weighted equally at two points in the momentum space without ZM coupling. The presence of ZM coupling induces an imbalanced particle distribution in the momentum space, and leads to the decrease of the amplitude of the stripe state. When its strength exceeds a critical value, the system experiences the transition from stripe phase to PW phase. The boundary of these two phases is shifted and a new phase diagram spanned by the ZM coupling and the interatomic interactions is obtained. The presence of ZM coupling can also achieve the transition from ZM phase to PW phase. In a strong harmonic trap, the condensate exhibits a vortex lattice state without ZM coupling. For the positive effective Rabi frequency of ZM coupling, the condensate is driven from a vortex lattice state to a vortex-free lattice state and finally to a PW state with the increase of coupling strength. In addition, for the negative effective Rabi frequency, the condensate is driven from a vortex lattice state to a stripe state, and finally to a PW state. The stripe state found in the strong harmonic trap is different from that in previous works because of its nonzero superfluid velocity along the stripes. We also discuss the influences of the ZM coupling on the spin textures, and indicate that the spin textures are squeezed transversely by the ZM coupling.
7. Enabling technologies for transition to utilization of space-based resources and operations
NASA Technical Reports Server (NTRS)
Sadin, S. R.; Litty, J. D.
1985-01-01
This article explores a potential scenario for the further development of space infrastructure resources and operations management. It is a scenario that transitions from the current ground-based system to an architecture that is predominantly space-based by exploiting key mission systems in an operational support role. If this view is accurate, an examination of the range of potential infrastructure elements and how they might interact in a maximally productive space-based operations complex is needed, innovative technologies beyond the current Shuttle and Space Station legacy need to be identified, and research programs pursued. Development of technologies within the areas of telerobotics, machine autonomy, human autonomy, in-space manufacturing and construction, propulsion and energy is discussed.
8. Space science public outreach at Louisiana State University
Guzik, T. G.; Babin, E.; Cooney, W.; Giammanco, J.; Hartman, D.; McNeil, R.; Slovak, M.; Stacy, J. G.
2004-01-01
Over the last seven years the Astronomy/Astrophysics group in the Department of Physics and Astronomy of Louisiana State University has developed an extensive Space Science education and public outreach program. This program includes partners from state and parish government, the local community, museums and school districts and has directly led to the development of the Highland Road Park Observatory, in-service teacher training program, content standards aligned classroom material and new technology for the classroom. In addition, a new planetarium/space theater opening soon in downtown Baton Rouge, Louisiana will provide our group with new space science education and public outreach opportunities. In this paper, we will discuss details about some of our individual projects.
9. Magnetic ground state of semiconducting transition-metal trichalcogenide monolayers
SciTech Connect
Sivadas, Nikhil; Daniels, Matthew W.; Swendsen, Robert H.; Okamoto, Satoshi; Xiao, Di
2015-06-16
Layered transition-metal trichalcogenides with the chemical formula ABX3 have attracted recent interest as potential candidates for two-dimensional magnets. Using first-principles calculations within density functional theory, we investigate the magnetic ground states of monolayers of Mn- and Cr-based semiconducting trichalcogenides.We show that the second and third nearest-neighbor exchange interactions (J2 and J3) between magnetic ions, which have been largely overlooked in previous theoretical studies, are crucial in determining the magnetic ground state. Specifically, we find that monolayer CrSiTe3 is an antiferromagnet with a zigzag spin texture due to significant contribution from J3, whereas CrGeTe3 is a ferromagnet with a Curie temperature of 106 K. Monolayers of Mn compounds (MnPS3 and MnPSe3) always show antiferromagnetic N eel order. We identify the physical origin of various exchange interactions, and demonstrate that strain can be an effective knob for tuning the magnetic properties. Possible magnetic ordering in the bulk is also discussed. In conclusion, our study suggests that ABX3 can be a promising platform to explore two-dimensional magnetic phenomena.
10. Magnetic ground state of semiconducting transition-metal trichalcogenide monolayers
DOE PAGESBeta
Sivadas, Nikhil; Daniels, Matthew W.; Swendsen, Robert H.; Okamoto, Satoshi; Xiao, Di
2015-06-16
Layered transition-metal trichalcogenides with the chemical formula ABX3 have attracted recent interest as potential candidates for two-dimensional magnets. Using first-principles calculations within density functional theory, we investigate the magnetic ground states of monolayers of Mn- and Cr-based semiconducting trichalcogenides.We show that the second and third nearest-neighbor exchange interactions (J2 and J3) between magnetic ions, which have been largely overlooked in previous theoretical studies, are crucial in determining the magnetic ground state. Specifically, we find that monolayer CrSiTe3 is an antiferromagnet with a zigzag spin texture due to significant contribution from J3, whereas CrGeTe3 is a ferromagnet with a Curie temperaturemore » of 106 K. Monolayers of Mn compounds (MnPS3 and MnPSe3) always show antiferromagnetic N eel order. We identify the physical origin of various exchange interactions, and demonstrate that strain can be an effective knob for tuning the magnetic properties. Possible magnetic ordering in the bulk is also discussed. In conclusion, our study suggests that ABX3 can be a promising platform to explore two-dimensional magnetic phenomena.« less
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https://docs.pymc.io/notebooks/normalizing_flows_overview.html
|
# Normalizing Flows Overview¶
Normalizing Flows is a rich family of distributions. They were described by Rezende and Mohamed, and their experiments proved the importance of studying them further. Some extensions like that of Tomczak and Welling made partially/full rank Gaussian approximations for high dimensional spaces computationally tractable.
This notebook reveals some tips and tricks for using normalizing flows effectively in PyMC3.
[1]:
%matplotlib inline
import matplotlib.pyplot as plt
import seaborn as sns
import pymc3 as pm
import numpy as np
from theano import theano, tensor as tt
from collections import Counter
pm.set_tt_rng(42)
np.random.seed(42)
## Theory¶
Normalizing flows is a series of invertible transformations on an initial distribution.
$z_K = f_K \circ \dots \circ f_2 \circ f_1(z_0)$
In this case, we can compute a tractable density for the flow.
$\ln q_K(z_K) = \ln q_0(z_0) - \sum_{k=1}^{K}\ln \left|\frac{\partial f_k}{\partial z_{k-1}}\right|$
Here, every $$f_k$$ is a parametric function with a well-defined determinant. The transformation used is up to the user; for example, the simplest flow is an affine transform:
$z = loc(scale(z_0)) = \mu + \sigma * z_0$
In this case, we get a mean field approximation if $$z_0 \sim \mathcal{N}(0, 1)$$
## Flow Formulas¶
In PyMC3 there are flexible ways to define flows with formulas. There are currently 5 types defined:
• Loc (loc): $$z' = z + \mu$$
• Scale (scale): $$z' = \sigma * z$$
• Planar (planar): $$z' = z + u * \tanh(w^T z + b)$$
• Radial (radial): $$z' = z + \beta (\alpha + ||z-z_r||)^{-1}(z-z_r)$$
• Householder (hh): $$z' = H z$$
Formulae can be composed as a string, e.g. 'scale-loc', 'scale-hh*4-loc', 'panar*10'. Each step is separated with '-', and repeated flows are defined with '*' in the form of '<flow>*<#repeats>'.
Flow-based approximations in PyMC3 are based on the NormalizingFlow class, with corresponding inference classes named using the NF abbreviation (analogous to how ADVI and SVGD are treated in PyMC3).
Concretely, an approximation is represented by:
[2]:
pm.NormalizingFlow
[2]:
pymc3.variational.approximations.NormalizingFlow
While an inference class is:
[3]:
pm.NFVI
[3]:
pymc3.variational.inference.NFVI
## Flow patterns¶
Composing flows requires some understanding of the target output. Flows that are too complex might not converge, whereas if they are too simple, they may not accurately estimate the posterior.
Let’s start simply:
[4]:
with pm.Model() as dummy:
N = pm.Normal('N', shape=(100,))
### Mean Field connectivity¶
Let’s apply the transformation corresponding to the mean-field family to begin with:
[5]:
pm.NormalizingFlow('scale-loc', model=dummy)
[5]:
<pymc3.variational.approximations.NormalizingFlow at 0x109b841d0>
### Full Rank Normal connectivity¶
We can get a full rank model with dense covariance matrix using householder flows (hh). One hh flow adds exactly one rank to the covariance matrix, so for a full rank matrix we need K=ndim householder flows. hh flows are volume-preserving, so we need to change the scaling if we want our posterior to have unit variance for the latent variables.
After we specify the covariance with a combination of 'scale-hh*K', we then add location shift with the loc flow. We now have a full-rank analog:
[6]:
pm.NormalizingFlow('scale-hh*100-loc', model=dummy)
[6]:
<pymc3.variational.approximations.NormalizingFlow at 0x1156df0b8>
A more interesting case is when we do not expect a lot of interactions within the posterior. In this case, where our covariance is expected to be sparse, we can constrain it by defining a low rank approximation family.
This has the additional benefit of reducing the computational cost of approximating the model.
[7]:
pm.NormalizingFlow('scale-hh*10-loc', model=dummy)
[7]:
<pymc3.variational.approximations.NormalizingFlow at 0x1156dfeb8>
Parameters can be initialized randomly, using the jitter argument to specify the scale of the randomness.
[8]:
pm.NormalizingFlow('scale-hh*10-loc', model=dummy, jitter=.001) # LowRank
[8]:
<pymc3.variational.approximations.NormalizingFlow at 0x115fea7f0>
### Planar and Radial Flows¶
• Planar (planar): $$z' = z + u * \tanh(w^T z + b)$$
• Radial (radial): $$z' = z + \beta (\alpha + ||z-z_r||)^{-1}(z-z_r)$$
Planar flows are useful for splitting the incoming distribution into two parts, which allows multimodal distributions to be modeled.
Similarly, a radial flow changes density around a specific reference point.
## Simulated data example¶
There were 4 potential functions illustrated in the original paper, which we can replicate here. Inference can be unstable in multimodal cases, but there are strategies for dealing with them.
First, let’s specify the potential functions:
[9]:
def w1(z):
return tt.sin(2.*np.pi*z[0]/4.)
def w2(z):
return 3.*tt.exp(-.5*(((z[0]-1.)/.6))**2)
def w3(z):
return 3.*(1+tt.exp(-(z[0]-1.)/.3))**-1
def pot1(z):
z = z.T
return .5*((z.norm(2, axis=0)-2.)/.4)**2 - tt.log(tt.exp(-.5*((z[0]-2.)/.6)**2) +
tt.exp(-.5*((z[0]+2.)/.6)**2))
def pot2(z):
z = z.T
return .5*((z[1]-w1(z))/.4)**2 + 0.1*tt.abs_(z[0])
def pot3(z):
z = z.T
return -tt.log(tt.exp(-.5*((z[1]-w1(z))/.35)**2) +
tt.exp(-.5*((z[1]-w1(z)+w2(z))/.35)**2)) + 0.1*tt.abs_(z[0])
def pot4(z):
z = z.T
return -tt.log(tt.exp(-.5*((z[1]-w1(z))/.4)**2) +
tt.exp(-.5*((z[1]-w1(z)+w3(z))/.35)**2)) + 0.1*tt.abs_(z[0])
z = tt.matrix('z')
z.tag.test_value = pm.floatX([[0., 0.]])
pot1f = theano.function([z], pot1(z))
pot2f = theano.function([z], pot2(z))
pot3f = theano.function([z], pot3(z))
pot4f = theano.function([z], pot4(z))
[10]:
def contour_pot(potf, ax=None, title=None, xlim=5, ylim=5):
grid = pm.floatX(np.mgrid[-xlim:xlim:100j,-ylim:ylim:100j])
grid_2d = grid.reshape(2, -1).T
cmap = plt.get_cmap('inferno')
if ax is None:
_, ax = plt.subplots(figsize=(12, 9))
pdf1e = np.exp(-potf(grid_2d))
contour = ax.contourf(grid[0], grid[1], pdf1e.reshape(100, 100), cmap=cmap)
if title is not None:
ax.set_title(title, fontsize=16)
return ax
[11]:
fig, ax = plt.subplots(2, 2, figsize=(12, 12))
ax = ax.flatten()
contour_pot(pot1f, ax[0], 'pot1', );
contour_pot(pot2f, ax[1], 'pot2');
contour_pot(pot3f, ax[2], 'pot3');
contour_pot(pot4f, ax[3], 'pot4');
fig.tight_layout()
## Reproducing first potential function¶
[12]:
from pymc3.distributions.dist_math import bound
def cust_logp(z):
#return bound(-pot1(z), z>-5, z<5)
return -pot1(z)
with pm.Model() as pot1m:
pm.DensityDist('pot1', logp=cust_logp, shape=(2,))
### NUTS¶
Let’s use NUTS first. Just to have a look how good is it’s approximation.
Note you may need to rerun the model a couple of times, as the sampler/estimator might not fully explore function due to multimodality.
[13]:
pm.set_tt_rng(42)
np.random.seed(42)
with pot1m:
trace = pm.sample(1000, init='auto', cores=2, start=[dict(pot1=np.array([-2, 0])),
dict(pot1=np.array([2, 0]))])
Auto-assigning NUTS sampler...
Initializing NUTS using jitter+adapt_diag...
99%|█████████▊| 1481/1500 [00:03<00:00, 473.27it/s]/Users/ferres/dev/pymc3/pymc3/step_methods/hmc/nuts.py:451: UserWarning: The acceptance probability in chain 0 does not match the target. It is 0.889185534675, but should be close to 0.8. Try to increase the number of tuning steps.
% (self._chain_id, mean_accept, target_accept))
100%|██████████| 1500/1500 [00:03<00:00, 467.67it/s]
[14]:
dftrace = pm.trace_to_dataframe(trace)
sns.jointplot(dftrace.iloc[:, 0], dftrace.iloc[:, 1], kind='kde')
[14]:
<seaborn.axisgrid.JointGrid at 0x116b9a208>
### Normalizing flows¶
As a first (naive) try with flows, we will keep things simple: Let’s use just 2 planar flows and see what we get:
[15]:
with pot1m:
inference = pm.NFVI('planar*2', jitter=1)
## Plotting starting distribution
dftrace = pm.trace_to_dataframe(inference.approx.sample(1000))
sns.jointplot(dftrace.iloc[:, 0], dftrace.iloc[:, 1], kind='kde');
#### Tracking gradients¶
It is illustrative to track gradients as well as parameters. In this setup, different sampling points can give different gradients because a single sampled point tends to collapse to a mode.
Here are the parameters of the model:
[16]:
inference.approx.params
[16]:
[b, u, w, b, u, w]
We also require an objective:
[17]:
inference.objective(nmc=None)
[17]:
Elemwise{mul,no_inplace}.0
Theano can be used to calcuate the gradient of the objective with respect to the parameters:
[18]:
with theano.configparser.change_flags(compute_test_value='off'):
grads = tt.grad(inference.objective(None), inference.approx.params)
grads
[18]:
[Elemwise{add,no_inplace}.0,
Elemwise{add,no_inplace}.0,
Elemwise{add,no_inplace}.0,
Elemwise{add,no_inplace}.0,
Elemwise{add,no_inplace}.0,
Elemwise{add,no_inplace}.0]
If we want to keep track of the gradient changes during the inference, we warp them in a pymc3 callback:
[19]:
from collections import defaultdict, OrderedDict
from itertools import count
@theano.configparser.change_flags(compute_test_value='off')
def get_tracker(inference):
numbers = defaultdict(count)
params = inference.approx.params
grads = tt.grad(inference.objective(None), params)
names = ['%s_%d' % (v.name, next(numbers[v.name])) for v in inference.approx.params]
return pm.callbacks.Tracker(**OrderedDict(
[(name, v.eval) for name, v in zip(names, params)] + [('grad_' + name, v.eval) for name, v in zip(names, grads)]
))
tracker = get_tracker(inference)
[20]:
tracker.whatchdict
[20]:
{'b_0': <bound method Variable.eval of b>,
'b_1': <bound method Variable.eval of b>,
'grad_b_0': <bound method Variable.eval of Elemwise{add,no_inplace}.0>,
'grad_b_1': <bound method Variable.eval of Elemwise{add,no_inplace}.0>,
'grad_u_0': <bound method Variable.eval of Elemwise{add,no_inplace}.0>,
'grad_u_1': <bound method Variable.eval of Elemwise{add,no_inplace}.0>,
'grad_w_0': <bound method Variable.eval of Elemwise{add,no_inplace}.0>,
'grad_w_1': <bound method Variable.eval of Elemwise{add,no_inplace}.0>,
'u_0': <bound method Variable.eval of u>,
'u_1': <bound method Variable.eval of u>,
'w_0': <bound method Variable.eval of w>,
'w_1': <bound method Variable.eval of w>}
[21]:
inference.fit(30000, obj_optimizer=pm.adagrad_window(learning_rate=.01), callbacks=[tracker])
Average Loss = -0.7863: 100%|██████████| 30000/30000 [00:55<00:00, 541.29it/s]
Finished [100%]: Average Loss = -0.79931
[21]:
<pymc3.variational.approximations.NormalizingFlow at 0x1166a64e0>
[22]:
dftrace = pm.trace_to_dataframe(inference.approx.sample(1000))
sns.jointplot(dftrace.iloc[:, 0], dftrace.iloc[:, 1], kind='kde')
[22]:
<seaborn.axisgrid.JointGrid at 0x11e519860>
[23]:
plt.plot(inference.hist);
As you can see, the objective history is not very informative here. This is where the gradient tracker can be more informative.
[24]:
trackername = ['u_0', 'w_0', 'b_0', 'u_1', 'w_1', 'b_1',
'grad_u_0', 'grad_w_0', 'grad_b_0', 'grad_u_1', 'grad_w_1', 'grad_b_1']
def plot_tracker_results(tracker):
fig, ax = plt.subplots(len(tracker.hist)//2, 2, figsize=(16, len(tracker.hist)//2*2.3))
ax = ax.flatten()
#names = list(tracker.hist.keys())
names = trackername
gnames = names[len(names)//2:]
names = names[:len(names)//2]
pairnames = zip(names, gnames)
def plot_params_and_grads(name, gname):
i = names.index(name)
left = ax[i*2]
right = ax[i*2+1]
grads = np.asarray(tracker[gname])
if grads.ndim == 1:
grads = grads[:, None]
grads = grads.T
params = np.asarray(tracker[name])
if params.ndim == 1:
params = params[:, None]
params = params.T
right.set_title('Gradient of %s' % name)
left.set_title('Param trace of %s' % name)
s = params.shape[0]
for j, (v, g) in enumerate(zip(params, grads)):
left.plot(v, '-')
right.plot(g, 'o', alpha=1/s/10)
left.legend([name + '_%d' % j for j in range(len(names))])
right.legend([gname + '_%d' % j for j in range(len(names))])
for vn, gn in pairnames:
plot_params_and_grads(vn, gn)
fig.tight_layout()
[25]:
plot_tracker_results(tracker);
Inference is often unstable, some parameters are not well fitted as they poorly influence the resulting posterior.
In a multimodal setting, the dominant mode might well change from run to run.
### Going deeper¶
We can try to improve our approximation by adding flows; in the original paper they used both 8 and 32. Let’s try using 8 here.
[26]:
with pot1m:
inference = pm.NFVI('planar*8', jitter=1.)
dftrace = pm.trace_to_dataframe(inference.approx.sample(1000))
sns.jointplot(dftrace.iloc[:, 0], dftrace.iloc[:, 1], kind='kde');
We can try for a more robust fit by allocating more samples to obj_n_mc in fit, which controls the number of Monte Carlo samples used to approximate the gradient.
[27]:
inference.fit(25000, obj_optimizer=pm.adam(learning_rate=.01), obj_n_mc=100,
callbacks=[pm.callbacks.CheckParametersConvergence()])
Average Loss = -1.7429: 100%|██████████| 25000/25000 [01:56<00:00, 215.40it/s]
Finished [100%]: Average Loss = -1.7428
[27]:
<pymc3.variational.approximations.NormalizingFlow at 0x11cfa3198>
[28]:
dftrace = pm.trace_to_dataframe(inference.approx.sample(1000))
sns.jointplot(dftrace.iloc[:, 0], dftrace.iloc[:, 1], kind='kde')
[28]:
<seaborn.axisgrid.JointGrid at 0x122108ac8>
This is a noticeable improvement. Here, we see that flows are able to characterize the multimodality of a given posterior, but as we have seen, they are hard to fit. The initial point of the optimization matters in general for the multimodal case.
### MCMC vs NFVI¶
Let’s use another potential function, and compare the sampling using NUTS to what we get with NF:
[29]:
def cust_logp(z):
return -pot4(z)
with pm.Model() as pot_m:
pm.DensityDist('pot_func', logp=cust_logp, shape=(2,))
[30]:
with pot_m:
traceNUTS = pm.sample(3000, tune=1000, target_accept=0.9, cores=2)
Auto-assigning NUTS sampler...
Initializing NUTS using jitter+adapt_diag...
99%|█████████▉| 3969/4000 [00:09<00:00, 393.42it/s]/Users/ferres/dev/pymc3/pymc3/step_methods/hmc/nuts.py:467: UserWarning: Chain 0 contains 94 diverging samples after tuning. If increasing target_accept does not help try to reparameterize.
% (self._chain_id, n_diverging))
100%|██████████| 4000/4000 [00:09<00:00, 402.32it/s]
/Users/ferres/dev/pymc3/pymc3/step_methods/hmc/nuts.py:451: UserWarning: The acceptance probability in chain 1 does not match the target. It is 0.632933350266, but should be close to 0.8. Try to increase the number of tuning steps.
% (self._chain_id, mean_accept, target_accept))
/Users/ferres/dev/pymc3/pymc3/step_methods/hmc/nuts.py:467: UserWarning: Chain 1 contains 84 diverging samples after tuning. If increasing target_accept does not help try to reparameterize.
% (self._chain_id, n_diverging))
[32]:
formula = 'planar*10'
with pot_m:
inference = pm.NFVI(formula, jitter=0.1)
inference.fit(25000, obj_optimizer=pm.adam(learning_rate=.01), obj_n_mc=10)
traceNF = inference.approx.sample(5000)
Average Loss = -2.212: 100%|██████████| 25000/25000 [01:05<00:00, 381.94it/s]
Finished [100%]: Average Loss = -2.2131
[33]:
fig, ax = plt.subplots(1, 3, figsize=(18, 6))
contour_pot(pot4f, ax[0], 'Target Potential Function');
ax[1].scatter(traceNUTS['pot_func'][:,0], traceNUTS['pot_func'][:,1],c='r',alpha=.05)
ax[1].set_xlim(-5,5)
ax[1].set_ylim(-5,5)
ax[1].set_title('NUTS')
ax[2].scatter(traceNF['pot_func'][:,0], traceNF['pot_func'][:,1],c='b',alpha=.05)
ax[2].set_xlim(-5,5)
ax[2].set_ylim(-5,5)
ax[2].set_title('NF with ' + formula);
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|
http://hackage.haskell.org/package/shake-0.10.8/docs/Development-Shake.html
|
shake-0.10.8: Build system library, like Make, but more accurate dependencies.
Development.Shake
Description
This module is used for defining Shake build systems. As a simple example of a Shake build system, let us build the file result.tar from the files listed by result.txt:
import Development.Shake
import Development.Shake.FilePath
main = shakeArgs shakeOptions $do want ["result.tar"] "*.tar" *> \out -> do contents <- readFileLines$ out -<.> "txt"
need contents
cmd "tar -cf" [out] contents
We start by importing the modules defining both Shake and routines for manipulating FilePath values. We define main to call shake with the default shakeOptions. As the second argument to shake, we provide a set of rules. There are two common forms of rules, want to specify target files, and *> to define a rule which builds a FilePattern. We use want to require that after the build completes the file result.tar should be ready.
The *.tar rule describes how to build files with the extension .tar, including result.tar. We readFileLines on result.txt, after changing the .tar extension to .txt. We read each line into the variable contents -- being a list of the files that should go into result.tar. Next, we depend (need) all the files in contents. If any of these files change, the rule will be repeated. Finally we call the tar program. If either result.txt changes, or any of the files listed by result.txt change, then result.tar will be rebuilt.
The theory behind Shake is described in an ICFP 2012 paper, Shake Before Building -- Replacing Make with Haskell http://community.haskell.org/~ndm/downloads/paper-shake_before_building-10_sep_2012.pdf. The associated talk forms a short overview of Shake http://www.youtube.com/watch?v=xYCPpXVlqFM.
== WRITING A BUILD SYSTEM ==============================
When writing a Shake build system, start by defining what you want, then write rules with *> to produce the results. Before calling cmd you should ensure that any files the command requires are demanded with calls to need. We offer the following advice to Shake users:
• If ghc --make or cabal is capable of building your project, use that instead. Custom build systems are necessary for many complex projects, but many projects are not complex.
• The shakeArgs function automatically handles command line arguments. To define non-file targets use phony.
• Put all result files in a distinguished directory, for example _make. You can implement a clean command by removing that directory, using removeFilesAfter "_make" ["//*"].
• To obtain parallel builds set shakeThreads to a number greater than 1.
• Lots of compilers produce .o files. To avoid overlapping rules, use .c.o for C compilers, .hs.o for Haskell compilers etc.
• Do not be afraid to mix Shake rules, system commands and other Haskell libraries -- use each for what it does best.
• The more accurate the dependencies are, the better. Use additional rules like doesFileExist and getDirectoryFiles to track information other than just the contents of files. For information in the environment that you suspect will change regularly (perhaps ghc version number), either write the information to a file with alwaysRerun and writeFileChanged, or use addOracle.
== GHC BUILD FLAGS ==============================
For large build systems the choice of GHC flags can have a significant impact. We recommend:
ghc --make MyBuildSystem -rtsopts "-with-rtsopts=-I0 -qg -qb"
• Compile without -threaded: In GHC 7.6 and earlier bug 7646 http://ghc.haskell.org/trac/ghc/ticket/7646 can cause a race condition in build systems that write files then read them. Omitting -threaded will still allow your cmd actions to run in parallel, so most build systems will still run in parallel.
• Compile with -rtsopts: Allow the setting of further GHC options at runtime.
• Run with -I0: Disable idle garbage collection. In a build system regularly running many system commands the program appears "idle" very often, triggering regular unnecessary garbage collection, stealing resources from the program doing actual work.
• Run with -qg -qb: Disable parallel garbage collection. Parallel garbage collection in Shake programs typically goes slower than sequential garbage collection, while occupying many cores that can be used for running system commands.
Acknowledgements: Thanks to Austin Seipp for properly integrating the profiling code.
Synopsis
# Core
shake :: ShakeOptions -> Rules () -> IO ()Source
Main entry point for running Shake build systems. For an example see the top of the module Development.Shake. Use ShakeOptions to specify how the system runs, and Rules to specify what to build. The function will throw an exception if the build fails.
To use command line flags to modify ShakeOptions see shakeArgs.
The default set of ShakeOptions.
type ShakeValue a = (Show a, Typeable a, Eq a, Hashable a, Binary a, NFData a)Source
Define an alias for the six type classes required for things involved in Shake Rules. This alias is only available in GHC 7.4 and above, and requires the ConstraintKinds extension.
To define your own values meeting the necessary constraints it is convenient to use the extensions GeneralizedNewtypeDeriving and DeriveDataTypeable to write:
newtype MyType = MyType (String, Bool) deriving (Show,Typeable,Eq,Hashable,Binary,NFData)
class (ShakeValue key, ShakeValue value) => Rule key value whereSource
Define a pair of types that can be used by Shake rules. To import all the type classes required see Development.Shake.Classes.
Methods
storedValue :: key -> IO (Maybe value)Source
Retrieve the value associated with a key, if available.
As an example for filenames/timestamps, if the file exists you should return Just the timestamp, but otherwise return Nothing. For rules whose values are not stored externally, storedValue should return Nothing.
data Rules a Source
Define a set of rules. Rules can be created with calls to rule, defaultRule or action. Rules are combined with either the Monoid instance, or (more commonly) the Monad instance and do notation.
Instances
Monad Rules Functor Rules Applicative Rules Monoid a => Monoid (Rules a)
defaultRule :: Rule key value => (key -> Maybe (Action value)) -> Rules ()Source
Like rule, but lower priority, if no rule exists then defaultRule is checked. All default rules must be disjoint.
rule :: Rule key value => (key -> Maybe (Action value)) -> Rules ()Source
Add a rule to build a key, returning an appropriate Action. All rules must be disjoint. To define lower priority rules use defaultRule.
action :: Action a -> Rules ()Source
Run an action, usually used for specifying top-level requirements.
main = shake shakeOptions $do action$ do
b <- doesFileExist "file.src"
when b $need ["file.out"] This action builds file.out, but only if file.src exists. The action will be run in every build execution (unless withoutActions is used), so only cheap operations should be performed. For the standard requirement of only needing a fixed list of files in the action, see want. withoutActions :: Rules () -> Rules ()Source Remove all actions specified in a set of rules, usually used for implementing command line specification of what to build. data Action a Source The Action monad, use liftIO to raise IO actions into it, and need to execute files. Action values are used by rule and action. Instances Monad Action Functor Action Applicative Action MonadIO Action apply :: Rule key value => [key] -> Action [value]Source Execute a rule, returning the associated values. If possible, the rules will be run in parallel. This function requires that appropriate rules have been added with rule or defaultRule. apply1 :: Rule key value => key -> Action valueSource Apply a single rule, equivalent to calling apply with a singleton list. Where possible, use apply to allow parallelism. traced :: String -> IO a -> Action aSource Write an action to the trace list, along with the start/end time of running the IO action. The cmd and command functions automatically call traced. The trace list is used for profile reports (see shakeReport). liftIO :: MonadIO m => forall a. IO a -> m a actionOnException :: Action a -> IO b -> Action aSource If an exception is raised by the Action, perform some IO. actionFinally :: Action a -> IO b -> Action aSource After an Action, perform some IO, even if there is an exception. Error representing all expected exceptions thrown by Shake. Problems when executing rules will be raising using this exception type. Constructors ShakeException FieldsshakeExceptionTarget :: StringThe target that was being built when the exception occured. shakeExceptionStack :: [String]The stack of targets, where the shakeExceptionTarget is last. shakeExceptionInner :: SomeExceptionThe underlying exception that was raised. # Configuration Options to control the execution of Shake, usually specified by overriding fields in shakeOptions: shakeOptions{shakeThreads=4, shakeReport=Just "report.html"} The Data instance for this type reports the shakeProgress and shakeOutput fields as having the abstract type Function, because Data cannot be defined for functions. Constructors ShakeOptions FieldsshakeFiles :: FilePathDefaults to .shake. The prefix of the filename used for storing Shake metadata files. All metadata files will be named shakeFiles.extension, for some extension. shakeThreads :: IntDefaults to 1. Maximum number of rules to run in parallel, similar to make --jobs=N. For many build systems, a number equal to or slightly less than the number of physical processors works well. shakeVersion :: StringDefaults to 1. The version number of your build rules. Change the version number to force a complete rebuild, such as when making significant changes to the rules that require a wipe. The version number should be set in the source code, and not passed on the command line. shakeVerbosity :: VerbosityDefaults to Normal. What level of messages should be printed out. shakeStaunch :: BoolDefaults to False. Operate in staunch mode, where building continues even after errors, similar to make --keep-going. shakeReport :: Maybe FilePathDefaults to Nothing. Write an HTML profiling report to a file, showing which rules rebuilt, why, and how much time they took. Useful for improving the speed of your build systems. shakeLint :: BoolDefaults to False. Perform basic sanity checks during building, checking the current directory is not modified and that output files are not modified by multiple rules. These sanity checks do not check for missing or redundant dependencies. shakeFlush :: Maybe DoubleDefaults to Just 10. How often to flush Shake metadata files in seconds, or Nothing to never flush explicitly. It is possible that on abnormal termination (not Haskell exceptions) any rules that completed in the last shakeFlush seconds will be lost. shakeAssume :: Maybe AssumeDefaults to Nothing. Assume all build objects are clean/dirty, see Assume for details. Can be used to implement make --touch. shakeAbbreviations :: [(String, String)]Defaults to []. A list of substrings that should be abbreviated in status messages, and their corresponding abbreviation. Commonly used to replace the long paths (e.g. .make/i586-linux-gcc/output) with an abbreviation (e.g. $OUT). shakeStorageLog :: BoolDefaults to False. Write a message to shakeFiles.storage whenever a storage event happens which may impact on the current stored progress. Examples include database version number changes, database compaction or corrupt files. shakeLineBuffering :: BoolDefaults to True. Change stdout and stderr to line buffering while running Shake. shakeTimings :: BoolDefault to False. Print timing information for each stage at the end. shakeProgress :: IO Progress -> IO ()Defaults to no action. A function called when the build starts, allowing progress to be reported. The function is called on a separate thread, and that thread is killed when the build completes. For applications that want to display progress messages, progressSimple is often sufficient, but more advanced users should look at the Progress data type. shakeOutput :: Verbosity -> String -> IO ()Defaults to writing using putStrLn. A function called to output messages from Shake, along with the Verbosity at which that message should be printed. This function will be called atomically from all other shakeOutput functions. The Verbosity will always be greater than or higher than shakeVerbosity.
Instances
Data ShakeOptions Show ShakeOptions Typeable ShakeOptions
data Assume Source
The current assumptions made by the build system, used by shakeAssume. These options allow the end user to specify that any rules run are either to be treated as clean, or as dirty, regardless of what the build system thinks.
These assumptions only operate on files reached by the current action commands. Any other files in the database are left unchanged.
Constructors
AssumeDirty Assume that all rules reached are dirty and require rebuilding, equivalent to storedValue always returning Nothing. Useful to undo the results of AssumeClean, for benchmarking rebuild speed and for rebuilding if untracked dependencies have changed. This assumption is safe, but may cause more rebuilding than necessary. AssumeClean This assumption is unsafe, and may lead to incorrect build results in this run, and in future runs. Assume and record that all rules reached are clean and do not require rebuilding, provided the rule has a storedValue and has been built before. Useful if you have modified a file in some inconsequential way, such as only the comments or whitespace, and wish to avoid a rebuild. AssumeSkip This assumption is unsafe, and may lead to incorrect build results in this run. Assume that all rules reached are clean in this run. Only useful for benchmarking, to remove any overhead from running storedValue operations.
Instances
Bounded Assume Enum Assume Eq Assume Data Assume Ord Assume Show Assume Typeable Assume
## Command line
shakeArgs :: ShakeOptions -> Rules () -> IO ()Source
Run a build system using command line arguments for configuration. The available flags are those from shakeOptDescrs, along with a few additional make compatible flags that are not represented in ShakeOptions, such as --print-directory. If there are no file arguments then the Rules are used directly, otherwise the file arguments are wanted (after calling withoutActions). As an example:
main = shakeArgs shakeOptions{shakeFiles = "_make/", shakeProgress = progressSimple} $do phony "clean"$ removeFilesAfter "_make" ["//*"]
want ["_make/neil.txt","_make/emily.txt"]
"_make/*.txt" *> \out ->
... build action here ...
This build system will default to building neil.txt and emily.txt, while showing progress messages, and putting the Shake files in locations such as _make/.database. Some example command line flags:
• main --no-progress will turn off progress messages.
• main -j6 will build on 6 threads.
• main --help will display a list of supported flags.
• main clean will not build anything, but will remove the _make directory, including the any shakeFiles.
• main _make/henry.txt will not build neil.txt or emily.txt, but will instead build henry.txt.
shakeArgsWith :: ShakeOptions -> [OptDescr (Either String a)] -> ([a] -> [String] -> IO (Maybe (Rules ()))) -> IO ()Source
A version of shakeArgs with more flexible handling of command line arguments. The caller of shakeArgsWith can add additional flags (the second argument) and chose how to convert the flags/arguments into rules (the third argument). Given:
shakeArgsWith opts flags (\flagValues argValues -> result)
• opts is the initial ShakeOptions value, which may have some fields overriden by command line flags. This argument is usually shakeOptions, perhaps with a few fields overriden.
• flags is a list of flag descriptions, which either produce a String containing an error message (typically for flags with invalid arguments, .e.g. Left "could not parse as int"), or a value that is passed as flagValues. If you have no custom flags, pass [].
• flagValues is a list of custom flags that the user supplied. If flags == [] then this list will be [].
• argValues is a list of non-flag arguments, which are often treated as files and passed to want.
• result should produce a Nothing to indicate that no building needs to take place, or a Just providing the rules that should be used.
As an example of a build system that can use either gcc or distcc for compiling:
import System.Console.GetOpt
data Flags = DistCC deriving Eq
flags = [Option "" ["distcc"] (NoArg $Right DistCC) "Run distributed."] main = shakeArgsWith shakeOptions flags$ \flags targets -> return $Just$ do
if null targets then want ["result.exe"] else want targets
let compiler = if DistCC elem flags then "distcc" else "gcc"
"*.o" *> \out -> do
need ...
cmd compiler ...
...
Now you can pass --distcc to use the distcc compiler.
A list of command line options that can be used to modify ShakeOptions. Each option returns either an error message (invalid argument to the flag) or a function that changes some fields in ShakeOptions. The command line flags are make compatible where possbile, but additional flags have been added for the extra options Shake supports.
## Progress reporting
data Progress Source
Information about the current state of the build, obtained by passing a callback function to shakeProgress. Typically a program will use progressDisplay to poll this value and produce status messages, which is implemented using this data type.
Constructors
Progress FieldsisFailure :: !(Maybe String)Starts out Nothing, becomes Just a target name if a rule fails. countSkipped :: !IntNumber of rules which were required, but were already in a valid state. countBuilt :: !IntNumber of rules which were have been built in this run. countUnknown :: !IntNumber of rules which have been built previously, but are not yet known to be required. countTodo :: !IntNumber of rules which are currently required (ignoring dependencies that do not change), but not built. timeSkipped :: !DoubleTime spent building countSkipped rules in previous runs. timeBuilt :: !DoubleTime spent building countBuilt rules. timeUnknown :: !DoubleTime spent building countUnknown rules in previous runs. timeTodo :: !(Double, Int)Time spent building countTodo rules in previous runs, plus the number which have no known time (have never been built before).
Instances
Eq Progress Data Progress Ord Progress Show Progress Typeable Progress Monoid Progress
A simple method for displaying progress messages, suitable for using as shakeProgress. This function writes the current progress to the titlebar every five seconds using progressTitlebar, and calls any shake-progress program on the $PATH using progressProgram. progressDisplay :: Double -> (String -> IO ()) -> IO Progress -> IO ()Source Given a sampling interval (in seconds) and a way to display the status message, produce a function suitable for using as shakeProgress. This function polls the progress information every n seconds, produces a status message and displays it using the display function. Typical status messages will take the form of 1m25s (15%), indicating that the build is predicted to complete in 1 minute 25 seconds (85 seconds total), and 15% of the necessary build time has elapsed. This function uses past observations to predict future behaviour, and as such, is only guessing. The time is likely to go up as well as down, and will be less accurate from a clean build (as the system has fewer past observations). The current implementation is to predict the time remaining (based on timeTodo) and the work already done (timeBuilt). The percentage is then calculated as remaining / (done + remaining), while time left is calculated by scaling remaining by the observed work rate in this build, roughly done / time_elapsed. Set the title of the current console window to the given text. If the environment variable $TERM is set to xterm this uses xterm escape sequences. On Windows, if not detected as an xterm, this function uses the SetConsoleTitle API.
progressProgram :: IO (String -> IO ())Source
Call the program shake-progress if it is on the $PATH. The program is called with the following arguments: • --title=string - the string passed to progressProgram. • --state=Normal, or one of NoProgress, Normal, or Error to indicate what state the progress bar should be in. • --value=25 - the percent of the build that has completed, if not in NoProgress state. The program will not be called consecutively with the same --state and --value options. Windows 7 or higher users can get taskbar progress notifications by placing the following program in their $PATH: https://github.com/ndmitchell/shake/releases.
## Verbosity
data Verbosity Source
The verbosity data type, used by shakeVerbosity.
Constructors
Silent Don't print any messages. Quiet Only print essential messages, typically errors. Normal Print errors and # command-name file-name when running a traced command. Loud Print errors and full command lines when running a system' command. Chatty Print errors, full command line and status messages when starting a rule. Diagnostic Print messages for virtually everything (mostly for debugging).
Get the current verbosity level, as set by shakeVerbosity. If you want to output information to the console, you are recommended to use putLoud / putNormal / putQuiet, which ensures multiple messages are not interleaved.
Write a message to the output when the verbosity (shakeVerbosity) is appropriate. The output will not be interleaved with any other Shake messages (other than those generated by system commands).
Write a message to the output when the verbosity (shakeVerbosity) is appropriate. The output will not be interleaved with any other Shake messages (other than those generated by system commands).
Write a message to the output when the verbosity (shakeVerbosity) is appropriate. The output will not be interleaved with any other Shake messages (other than those generated by system commands).
quietly :: Action a -> Action aSource
Run an action with Quiet verbosity, in particular messages produced by traced (including from cmd or command) will not be printed to the screen.
# Running commands
command :: CmdResult r => [CmdOption] -> String -> [String] -> Action rSource
Execute a system command. Before running command make sure you need any files that are required by the command.
This function takes a list of options (often just [], see CmdOption for the available options), the name of the executable (either a full name, or a program on the $PATH) and a list of arguments. The result is often (), but can be a tuple containg any of Stdout, Stderr and Exit. Some examples: command_ [] "gcc" ["-c","myfile.c"] -- compile a file, throwing an exception on failure Exit c <- command [] "gcc" ["-c",myfile] -- run a command, recording the exit code (Exit c, Stderr err) <- command [] "gcc" ["-c","myfile.c"] -- run a command, recording the exit code and error output Stdout out <- command [] "gcc" ["-MM","myfile.c"] -- run a command, recording the output command_ [Cwd "generated"] "gcc" ["-c",myfile] -- run a command in a directory Unless you retrieve the ExitCode using Exit, any ExitFailure will throw an error, including the Stderr in the exception message. If you capture the Stdout or Stderr, that stream will not be echoed to the console, unless you use the option EchoStdout or EchoStderr. If you use command inside a do block and do not use the result, you may get a compile-time error about being unable to deduce CmdResult. To avoid this error, use command_. command_ :: [CmdOption] -> String -> [String] -> Action ()Source A version of command where you do not require any results, used to avoid errors about being unable to deduce CmdResult. cmd :: CmdArguments args => args :-> Action rSource A variable arity version of command. • String arguments are treated as whitespace separated arguments. • [String] arguments are treated as literal arguments. • CmdOption arguments are used as options. To take the examples from command: () <- cmd "gcc -c myfile.c" -- compile a file, throwing an exception on failure Exit c <- cmd "gcc -c" [myfile] -- run a command, recording the exit code (Exit c, Stderr err) <- cmd "gcc -c myfile.c" -- run a command, recording the exit code and error output Stdout out <- cmd "gcc -MM myfile.c" -- run a command, recording the output cmd (Cwd "generated") "gcc -c" [myfile] :: Action () -- run a command in a directory When passing file arguments we use [myfile] so that if the myfile variable contains spaces they are properly escaped. If you use cmd inside a do block and do not use the result, you may get a compile-time error about being unable to deduce CmdResult. To avoid this error, bind the result to (), or include a type signature. newtype Stdout Source Collect the stdout of the process. If you are collecting the stdout, it will not be echoed to the terminal, unless you include EchoStdout. Constructors Stdout FieldsfromStdout :: String Instances CmdResult Stdout newtype Stderr Source Collect the stderr of the process. If you are collecting the stderr, it will not be echoed to the terminal, unless you include EchoStderr. Constructors Stderr FieldsfromStderr :: String Instances CmdResult Stderr newtype Exit Source Collect the ExitCode of the process. If you do not collect the exit code, any ExitFailure will cause an exception. Constructors Exit FieldsfromExit :: ExitCode Instances CmdResult Exit class CmdResult a Source A class for specifying what results you want to collect from a process. Values are formed of Stdout, Stderr, Exit and tuples of those. Instances CmdResult () CmdResult ExitCode CmdResult Exit CmdResult Stderr CmdResult Stdout (CmdResult x1, CmdResult x2) => CmdResult (x1, x2) (CmdResult x1, CmdResult x2, CmdResult x3) => CmdResult (x1, x2, x3) data CmdOption Source Options passed to command or cmd to control how processes are executed. Constructors Cwd FilePath Change the current directory in the spawned process. By default uses this processes current directory. Env [(String, String)] Change the environment variables in the spawned process. By default uses this processes environment. Stdin String Given as the stdin of the spawned process. By default no stdin is given. Shell Pass the command to the shell without escaping - any arguments will be joined with spaces. By default arguments are escaped properly. BinaryPipes Treat the stdin/stdout/stderr messages as binary. By default streams use text encoding. Traced String Name to use with traced, or "" for no tracing. By default traces using the name of the executable. WithStderr Bool Should I include the stderr in the exception if the command fails? Defaults to True. EchoStdout Bool Should I echo the stdout? Defaults to True unless a Stdout result is required. EchoStderr Bool Should I echo the stderr? Defaults to True unless a Stderr result is required. Instances Eq CmdOption Ord CmdOption Show CmdOption # Utility functions system' :: FilePath -> [String] -> Action ()Source Execute a system command. This function will raise an error if the exit code is non-zero. Before running system' make sure you need any required files. systemCwd :: FilePath -> FilePath -> [String] -> Action ()Source Deprecated: Please use command or cmd instead, with Cwd. This function will be removed in a future version. Execute a system command with a specified current working directory (first argument). This function will raise an error if the exit code is non-zero. Before running systemCwd make sure you need any required files. systemCwd "/usr/MyDirectory" "pwd" [] systemOutput :: FilePath -> [String] -> Action (String, String)Source Deprecated: Please use command or cmd instead, with Stdout or Stderr. This function will be removed in a future version. Execute a system command, returning (stdout,stderr). This function will raise an error if the exit code is non-zero. Before running systemOutput make sure you need any required files. copyFile' old new copies the existing file from old to new. The old file is has need called on it before copying the file. Read a file, after calling need. A version of readFile' which also splits the result into lines. Write a file, lifted to the Action monad. writeFileLines :: FilePath -> [String] -> Action ()Source A version of writeFile' which writes out a list of lines. Write a file, but only if the contents would change. removeFiles :: FilePath -> [FilePattern] -> IO ()Source Remove all empty directories and files that match any of the patterns beneath a directory. Some examples: removeFiles "output" ["//*"] removeFiles "." ["//*.hi","//*.o"] This function is often useful when writing a clean action for your build system, often as a phony rule. removeFilesAfter :: FilePath -> [FilePattern] -> Action ()Source Remove files, like removeFiles, but executed after the build completes successfully. Useful for implementing clean actions that delete files Shake may have open for building. # File rules need :: [FilePath] -> Action ()Source Require that the following files are built before continuing. Particularly necessary when calling cmd or command. As an example: "//*.rot13" *> \out -> do let src = dropExtension out need [src] cmd "rot13" [src] "-o" [out] want :: [FilePath] -> Rules ()Source Require that the following are built by the rules, used to specify the target. main = shake shakeOptions$ do
want ["Main.exe"]
...
This program will build Main.exe, given sufficient rules.
This function is defined in terms of action and need, use action if you need more complex targets than want allows.
(*>) :: FilePattern -> (FilePath -> Action ()) -> Rules ()Source
Define a rule that matches a FilePattern. No file required by the system must be matched by more than one pattern. For the pattern rules, see ?==.
"*.asm.o" *> \out -> do
let src = dropExtension out
need [src]
cmd "as" [src] "-o" [out]
To define a build system for multiple compiled languages, we recommend using .asm.o, .cpp.o, .hs.o, to indicate which language produces an object file. I.e., the file foo.cpp produces object file foo.cpp.o.
Note that matching is case-sensitive, even on Windows.
(**>) :: [FilePattern] -> (FilePath -> Action ()) -> Rules ()Source
Define a set of patterns, and if any of them match, run the associated rule. See *>.
(?>) :: (FilePath -> Bool) -> (FilePath -> Action ()) -> Rules ()Source
Define a rule to build files. If the first argument returns True for a given file, the second argument will be used to build it. Usually *> is sufficient, but ?> gives additional power. For any file used by the build system, only one rule should return True.
(all isUpper . takeBaseName) ?> \out -> do
let src = replaceBaseName out $map toLower$ takeBaseName out
writeFile' out . map toUpper =<< readFile' src
phony :: String -> Action () -> Rules ()Source
Declare a phony action -- an action that does not produce a file, and will be rerun in every execution that requires it. You can demand phony rules using want / need. Phony actions are never executed more than once in a single build run.
Phony actions are intended to define command-line abbreviations. If you need a phony action in a rule then every execution where that rule is required will rerun both the rule and the phony action.
(~>) :: String -> Action () -> Rules ()Source
Infix operator alias for phony, for sake of consistency with normal rules.
(?>>) :: (FilePath -> Maybe [FilePath]) -> ([FilePath] -> Action ()) -> Rules ()Source
Define a rule for building multiple files at the same time, a more powerful and more dangerous version of *>>.
Given an application test ?>> ..., test should return Just if the rule applies, and should return the list of files that will be produced. This list must include the file passed as an argument and should obey the invariant:
forAll $\x ys -> test x == Just ys ==> x elem ys && all ((== Just ys) . test) ys As an example of a function satisfying the invariaint: test x | takeExtension x elem [".hi",".o"] = Just [dropExtension x <.> "hi", dropExtension x <.> "o"] test _ = Nothing Regardless of whether Foo.hi or Foo.o is passed, the function always returns [Foo.hi, Foo.o]. (*>>) :: [FilePattern] -> ([FilePath] -> Action ()) -> Rules ()Source Define a rule for building multiple files at the same time. As an example, a single invokation of GHC produces both .hi and .o files: ["*.o","*.hi"] *>> \[o,hi] -> do let hs = o -<.> "hs" need ... -- all files the .hs import cmd "ghc -c" [hs] However, in practice, it's usually easier to define rules with *> and make the .hi depend on the .o. When defining rules that build multiple files, all the FilePattern values must have the same sequence of // and * wildcards in the same order. A type synonym for file patterns, containing // and *. For the syntax and semantics of FilePattern see ?==. Match a FilePattern against a FilePath, There are only two special forms: • * matches an entire path component, excluding any separators. • // matches an arbitrary number of path components. Some examples that match: "//*.c" ?== "foo/bar/baz.c" "*.c" ?== "baz.c" "//*.c" ?== "baz.c" "test.c" ?== "test.c" Examples that don't match: "*.c" ?== "foo/bar.c" "*/*.c" ?== "foo/bar/baz.c" An example that only matches on Windows: "foo/bar" ?== "foo\\bar" # Directory rules Returns True if the file exists. Returns True if the directory exists. Get the contents of a directory. The result will be sorted, and will not contain the entries . or .. (unlike the standard Haskell version). The resulting paths will be relative to the first argument. It is usually simpler to call either getDirectoryFiles or getDirectoryDirs. Get the files anywhere under a directory that match any of a set of patterns. For the interpretation of the patterns see ?==. All results will be relative to the FilePath argument. Some examples: getDirectoryFiles "Config" ["//*.xml"] -- All .xml files anywhere under the Config directory -- If Config/foo/bar.xml exists it will return ["foo/bar.xml"] getDirectoryFiles "Modules" ["*.hs","*.lhs"] -- All .hs or .lhs in the Modules directory -- If Modules/foo.hs and Modules/foo.lhs exist, it will return ["foo.hs","foo.lhs"] If you require a qualified file name it is often easier to use "" as FilePath argument, for example the following two expressions are equivalent: fmap (map ("Config" </>)) (getDirectoryFiles "Config" ["//*.xml"]) getDirectoryFiles "" ["Config//*.xml"] Get the directories in a directory, not including . or ... All directories are relative to the argument directory. getDirectoryDirs "/Users" -- Return all directories in the /Users directory -- e.g. ["Emily","Henry","Neil"] # Environment rules Return Just the value of the environment variable, or Nothing if the variable is not set. # Oracle rules addOracle :: (ShakeValue q, ShakeValue a) => (q -> Action a) -> Rules (q -> Action a)Source Add extra information which rules can depend on. An oracle is a function from a question type q, to an answer type a. As an example, we can define an oracle allowing you to depend on the current version of GHC: newtype GhcVersion = GhcVersion () deriving (Show,Typeable,Eq,Hashable,Binary,NFData) rules = do addOracle$ \(GhcVersion _) -> fmap fromStdout $cmd "ghc --numeric-version" ... rules ... If a rule calls askOracle (GhcVersion ()), that rule will be rerun whenever the GHC version changes. Some notes: • We define GhcVersion with a newtype around (), allowing the use of GeneralizedNewtypeDeriving. All the necessary type classes are exported from Development.Shake.Classes. • Each call to addOracle must use a different type of question. • Actions passed to addOracle will be run in every build they are required, but if their value does not change they will not invalidate any rules depending on them. To get a similar behaviour using data stored in files, see alwaysRerun. • If the value returned by askOracle is ignored then askOracleWith may help avoid ambiguous type messages. Alternatively, use the result of addOracle, which is askOracle restricted to the correct type. As a more complex example, consider tracking Haskell package versions: newtype GhcPkgList = GhcPkgList () deriving (Show,Typeable,Eq,Hashable,Binary,NFData) newtype GhcPkgVersion = GhcPkgVersion String deriving (Show,Typeable,Eq,Hashable,Binary,NFData) rules = do getPkgList <- addOracle$ \GhcPkgList{} -> do
Stdout out <- cmd "ghc-pkg list --simple-output"
return [(reverse b, reverse a) | x <- words out, let (a,_:b) = break (== '-') $reverse x] -- getPkgVersion <- addOracle$ \(GhcPkgVersion pkg) -> do
pkgs <- getPkgList $GhcPkgList () return$ lookup pkg pkgs
--
"myrule" *> \_ -> do
getPkgVersion $GhcPkgVersion "shake" ... rule using the shake version ... Using these definitions, any rule depending on the version of shake should call getPkgVersion$ GhcPkgVersion "shake" to rebuild when shake is upgraded.
askOracle :: (ShakeValue q, ShakeValue a) => q -> Action aSource
Get information previously added with addOracle. The question/answer types must match those provided to addOracle.
askOracleWith :: (ShakeValue q, ShakeValue a) => q -> a -> Action aSource
Get information previously added with addOracle. The second argument is not used, but can be useful to fix the answer type, avoiding ambiguous type error messages.
# Special rules
Always rerun the associated action. Useful for defining rules that query the environment. For example:
"ghcVersion.txt" *> \out -> do
alwaysRerun
Stdout stdout <- cmd "ghc --numeric-version"
writeFileChanged out stdout
# Resources
data Resource Source
A type representing an external resource which the build system should respect. There are two ways to create Resources in Shake:
• newResource creates a finite resource, stopping too many actions running simultaneously.
• newThrottle creates a throttled resource, stopping too many actions running over a short time period.
These resources are used with withResource when defining rules. Typically only system commands (such as cmd) should be run inside withResource, not commands such as need.
Be careful that the actions run within withResource do not themselves require further resources, or you may get a "thread blocked indefinitely in an MVar operation" exception. If an action requires multiple resources, use withResources to avoid deadlock.
Instances
Eq Resource Ord Resource Show Resource
Create a finite resource, given a name (for error messages) and a quantity of the resource that exists. Shake will ensure that actions using the same finite resource do not execute in parallel. As an example, only one set of calls to the Excel API can occur at one time, therefore Excel is a finite resource of quantity 1. You can write:
shake shakeOptions{shakeThreads=2} $do want ["a.xls","b.xls"] excel <- newResource "Excel" 1 "*.xls" *> \out -> withResource excel 1$
cmd "excel" out ...
Now the two calls to excel will not happen in parallel.
As another example, calls to compilers are usually CPU bound but calls to linkers are usually disk bound. Running 8 linkers will often cause an 8 CPU system to grid to a halt. We can limit ourselves to 4 linkers with:
disk <- newResource "Disk" 4
want [show i <.> "exe" | i <- [1..100]]
"*.exe" *> \out ->
withResource disk 1 $cmd "ld -o" [out] ... "*.o" *> \out -> cmd "cl -o" [out] ... A version of newResource that runs in IO, and can be called before calling shake. Most people should use newResource instead. withResource :: Resource -> Int -> Action a -> Action aSource Run an action which uses part of a finite resource. For more details see Resource. You cannot call apply / need while the resource is acquired. withResources :: [(Resource, Int)] -> Action a -> Action aSource Run an action which uses part of several finite resources. Acquires the resources in a stable order, to prevent deadlock. If all rules requiring more than one resource acquire those resources with a single call to withResources, resources will not deadlock. Create a throttled resource, given a name (for error messages) and a number of resources (the Int) that can be used per time period (the Double in seconds). Shake will ensure that actions using the same throttled resource do not exceed the limits. As an example, let us assume that making more than 1 request every 5 seconds to Google results in our client being blacklisted, we can write: google <- newThrottle "Google" 1 5 "*.url" *> \out -> do withResource google 1$
cmd "wget" ["http://google.com?q=" ++ takeBaseName out] "-O" [out]
Now we will wait at least 5 seconds after querying Google before performing another query. If Google change the rules to allow 12 requests per minute we can instead use newThrottle "Google" 12 60, which would allow greater parallelisation, and avoid throttling entirely if only a small number of requests are necessary.
In the original example we never make a fresh request until 5 seconds after the previous request has completed. If we instead want to throttle requests since the previous request started we can write:
google <- newThrottle "Google" 1 5
"*.url" *> \out -> do
withResource google 1 $return () cmd "wget" ["http://google.com?q=" ++ takeBaseName out] "-O" [out] However, the rule may not continue running immediately after withResource completes, so while we will never exceed an average of 1 request every 5 seconds, we may end up running an unbounded number of requests simultaneously. If this limitation causes a problem in practice it can be fixed. A version of newThrottle that runs in IO, and can be called before calling shake. Most people should use newResource instead. Run an action without counting to the thread limit, typically used for actions that execute on remote machines using barely any local CPU resources. Unsafe as it allows the shakeThreads limit to be exceeded. You cannot call apply / need while the extra thread is executing. # Cached file contents newCache :: (FilePath -> IO a) -> Rules (FilePath -> Action a)Source Given a way of loading information from a file, produce a cached version that will load each file at most once. Using the cached function will still result in a dependency on the original file. The argument function should not access any files other than the one passed as its argument. Each call to newCache creates a separate cache that is independent of all other calls to newCache. This function is useful when creating files that store intermediate values, to avoid the overhead of repeatedly reading from disk, particularly if the file requires expensive parsing. As an example: digits <- newCache$ \file -> do
return $length$ filter isDigit src
"*.digits" *> \x -> do
v1 <- digits (dropExtension x)
v2 <- digits (dropExtension x)
writeFile' x \$ show (v1,v2)
To create the result MyFile.txt.digits the file MyFile.txt will be read and counted, but only at most once per execution.
A version of newCache that runs in IO, and can be called before calling shake. Most people should use newCache instead.
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https://asmedigitalcollection.asme.org/GT/proceedings-abstract/GT2013/55157/V03BT13A041/249599
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Film-cooling is one of the most prevalent cooling technologies that is used for gas turbine airfoil surfaces. Numerous studies have been conducted to give the cooling effectiveness over ranges of velocity, density, mass flux, and momentum flux ratios. Few studies have reported flowfield measurements with even fewer of those providing time-resolved flowfields. This paper provides time-averaged and time-resolved particle image velocimetry data for a film-cooling flow at low and high density ratios. A generic film-cooling hole geometry with wide lateral spacing was used for this study, which was a 30° inclined round hole injecting along a flat plate with lateral spacing P/D = 6.7. The jet Reynolds number for flowfield testing varied from 2500 to 7000. The data indicate differences in the flowfield and turbulence characteristics for the same momentum flux ratios at the two density ratios. The time-resolved data indicate Kelvin-Helmholtz breakdown in the jet-to-freestream shear layer.
This content is only available via PDF.
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https://par.nsf.gov/search/author:%22Pettini,%20Max%22
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# Search for:All records
Creators/Authors contains: "Pettini, Max"
Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
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1. Abstract We report the first direct measurement of the helium isotope ratio, 3 He/ 4 He, outside of the Local Interstellar Cloud, as part of science-verification observations with the upgraded CRyogenic InfraRed Echelle Spectrograph. Our determination of 3 He/ 4 He is based on metastable He i * absorption along the line of sight toward Θ 2 A Ori in the Orion Nebula. We measure a value 3 He/ 4 He = (1.77 ± 0.13) × 10 −4 , which is just ∼40% above the primordial relative abundance of these isotopes, assuming the Standard Model of particle physics and cosmology, ( 3 He/ 4 He) p = (1.257 ± 0.017) × 10 −4 . We calculate a suite of galactic chemical evolution simulations to study the Galactic build up of these isotopes, using the yields from Limongi & Chieffi for stars in the mass range M = 8–100 M ⊙ and Lagarde et al. for M = 0.8–8 M ⊙ . We find that these simulations simultaneously reproduce the Orion and protosolar 3 He/ 4 He values if the calculations are initialized with a primordial ratio 3 He / 4 He p = ( 1.043 ± 0.089 ) × 10more »
Free, publicly-accessible full text available June 1, 2023
2. Abstract Detailed analyses of high-redshift galaxies are challenging because these galaxies are faint, but this difficulty can be overcome with gravitational lensing, in which the magnification of the flux enables spectroscopy with a high signal-to-noise ratio (S/N). We present the rest-frame ultraviolet (UV) Keck Echellette Spectrograph and Imager (ESI) spectrum of the newly discovered z = 2.79 lensed galaxy SDSS J1059+4251. With an observed magnitude F814W = 18.8 and a magnification factor μ = 31 ± 3, J1059+4251 is both highly magnified and intrinsically luminous, about two magnitudes brighter than M UV * at z ∼ 2–3. With a stellar mass M * = (3.22 ± 0.20) × 10 10 M ⊙ , star formation rate SFR = 50 ± 7 M ⊙ yr −1 , and stellar metallicity Z * ≃ 0.15–0.5 Z ⊙ , J1059+4251 is typical of bright star-forming galaxies at similar redshifts. Thanks to the high S/N and the spectral resolution of the ESI spectrum, we are able to separate the interstellar and stellar features and derive properties that would be inaccessible without the aid of the lensing. We find evidence of a gas outflow with speeds up to −1000 km s −1 , and ofmore »
3. ABSTRACT We present new measurements of the spatial distribution and kinematics of neutral hydrogen in the circumgalactic and intergalactic medium surrounding star-forming galaxies at z ∼ 2. Using the spectra of ≃3000 galaxies with redshifts 〈z〉 = 2.3 ± 0.4 from the Keck Baryonic Structure Survey, we assemble a sample of more than 200 000 distinct foreground-background pairs with projected angular separations of 3–500 arcsec and spectroscopic redshifts, with 〈zfg〉 = 2.23 and 〈zbg〉 = 2.57 (foreground, background redshifts, respectively.) The ensemble of sightlines and foreground galaxies is used to construct a 2D map of the mean excess $\rm{H\,{\small I}}$$\rm Ly\,\alpha$ optical depth relative to the intergalactic mean as a function of projected galactocentric distance (20 ≲ Dtran/pkpc ≲ 4000) and line-of-sight velocity. We obtain accurate galaxy systemic redshifts, providing significant information on the line-of-sight kinematics of $\rm{H\,{\small I}}$ gas as a function of projected distance Dtran. We compare the map with cosmological zoom-in simulation, finding qualitative agreement between them. A simple two-component (accretion, outflow) analytical model generally reproduces the observed line-of-sight kinematics and projected spatial distribution of $\rm{H\,{\small I}}$. The best-fitting model suggests that galaxy-scale outflows with initial velocity vout ≃ 600 km s$^{-1}\,$ dominate the kinematics of circumgalactic $\rm{H\,{\small I}}$ out to Dtran ≃ 50 kpc, whilemore »
4. ABSTRACT
The combination of the MOSDEF and KBSS-MOSFIRE surveys represents the largest joint investment of Keck/MOSFIRE time to date, with ∼3000 galaxies at 1.4 ≲ z ≲ 3.8, roughly half of which are at z ∼ 2. MOSDEF is photometric- and spectroscopic-redshift selected with a rest-optical magnitude limit, while KBSS-MOSFIRE is primarily selected based on rest-UV colours and a rest-UV magnitude limit. Analysing both surveys in a uniform manner with consistent spectral-energy-distribution (SED) models, we find that the MOSDEF z ∼ 2 targeted sample has higher median M* and redder rest U−V colour than the KBSS-MOSFIRE z ∼ 2 targeted sample, and smaller median SED-based SFR and sSFR (SFR(SED) and sSFR(SED)). Specifically, MOSDEF targeted a larger population of red galaxies with U−V and V−J ≥1.25, while KBSS-MOSFIRE contains more young galaxies with intense star formation. Despite these differences in the z ∼ 2 targeted samples, the subsets of the surveys with multiple emission lines detected and analysed in previous work are much more similar. All median host-galaxy properties with the exception of stellar population age – i.e. M*, SFR(SED), sSFR(SED), AV, and UVJ colours – agree within the uncertainties. Additionally, when uniform emission-line fitting and stellar Balmer absorption correction techniquesmore »
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https://ccssmathanswers.com/bridges-in-mathematics-grade-5-home-connections-unit-7-module-4-answer-key/
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# Bridges in Mathematics Grade 5 Home Connections Unit 7 Module 4 Answer Key
Students looking for the Bridges in Mathematics Grade 5 Home Connections Answer Key Unit 7 Module 4 can find a better approach to solve the problems.
## Bridges in Mathematics Grade 5 Home Connections Answer Key Unit 7 Module 4
Bridges in Mathematics Grade 5 Home Connections Unit 7 Module 4 Session 2 Answer Key
Olympic Swimmers
For each problem, first estimate the answer and then solve the problem. Show your thinking using words, numbers, or labeled sketches.
Question 1.
In the 2012 Olympics, U.S. athlete Nathan Adrian finished the 100-meter freestyle swim in 47.52 seconds. If Nathan swam at the same pace in a regular 25-meter pool, what would his time have been per lap?
Estimate _______________
Estimate: 48 seconds,
The time have been per lap is 47.52 seconds,
Explanation:
Given in the 2012 Olympics, U.S. athlete Nathan Adrian finished the 100-meter freestyle swim in 47.52 seconds. If Nathan swam at the same pace in a regular 25-meter pool, would his time have been per lap is also 47.52 seconds only because Nathan swam at the same pace therefore estimate near to 47.52 seconds is 48 seconds and the time have been per lap is 47.52 seconds for 25-meter pool.
Question 2.
Dana Vollmer set a world record in the 100-meter butterfly finals in London. Her time was 55.98 seconds. If Dana swam at the same pace in a 25-meter pool, what would her time be per lap?
Estimate _______________
Estimate: 56 seconds,
Dana Vollmer time per lap is 55.98 seconds,
Explanation:
Given Dana Vollmer set a world record in the 100-meter butterfly finals in London. Her time was 55.98 seconds. If Dana swam at the same pace in a 25-meter pool her time be per lap estimate would be approximately 56 seconds and her time have been per lap is same 55.98 seconds.
Question 3.
Missy Franklin competed in seven Olympic swimming events and posted five gold medals in London. Her time in the 100-meter backstroke was 58.33 seconds. If Missy swam at the same pace in a 25-meter pool, what would her time be per lap?
Estimate _______________
Estimate : 58 seconds,
Explanation:
Given Missy Franklin competed in seven Olympic swimming events and posted five gold medals in London. Her time in the 100-meter backstroke was 58.33 seconds. If Missy swam at the same pace in a 25-meter pool, her time be per lap estimate is approximately 58 and it is 58.33 seconds only.
Question 4.
In London in 2012, Michael Phelps won a gold medal for the 100-meter butterfly with a time of 51.21 seconds. If Michael had been swimming that event in a 25-meter pool, what would his time have been per lap?
Estimate _______________
Estimate: 51 seconds,
His time per lap is 51.21 seconds for 25-meter pool,
Explanation:
Given in London in 2012, Michael Phelps won a gold medal for the 100-meter butterfly with a time of 51.21 seconds. If Michael had been swimming that event in a 25-meter pool, So would his time have been per lap estimate is approximately 51 seconds and his time per lap is 51.21 seconds for 25-meter pool.
Question 5.
CHALLENGE In the men’s 400-meter relay, each of 4 team members swims a 100-meter leg for a total of 400 meters swum. One team swam the relay with a total time of 3 minutes and 29.32 seconds.
a. If each of the four members of the team posted the same time, what would their individual times be? (Hint: Think about how long it took the swimmers to swim each leg of the relay.)
Estimate _______________
Estimate: 29 seconds for all 4 members,
Individual times is 29.32 seconds,
Explanation:
Given in the men’s 400-meter relay, each of 4 team members swims a 100-meter leg for a total of 400 meters swum. One team swam the relay with a total time of 3 minutes and 29.32 seconds. If each of the four members of the team posted the same time it would their individual times be (29.32 seconds + 29.32 seconds + 29.32 seconds + 29.32 seconds)/4 = 29.32 seconds only and the estimate time for individual will be approximately 29.32 seconds.
b. An Olympic pool is 50 meters long, so in the 400-meter relay, each team member swims two 50-meter laps. If each member of this team swam their first lap just as fast as their second lap, how long did it take to swim each lap?
Estimate _______________
Estimate: 50 meters,
To swim each lap it took 50 meters,
Explanation:
Given an Olympic pool is 50 meters long, so in the 400-meter relay, each team member swims two 50-meter laps. If each member of this team swam their first lap just as fast as their second lap long did it take to swim each lap is estimate approximately 50 meters so it is 50 meters only.
Bridges in Mathematics Grade 5 Home Connections Unit 7 Module 4 Session 3 Answer Key
Olympic Track Star
Solve each problem. Show your thinking using words, numbers, or labeled sketches.
Question 1.
Usain Bolt won three gold medals in the Track and Field events in the 2012 Olympics in London. His times are posted below.
a. Usain ran the 200-meter race in 19.32 seconds. If he ran 100 meters at that speed, what would his 100 meter time be?
9.63 seconds,
Explanation:
Given Usain Bolt won three gold medals in the Track and Field events in the 2012 Olympics in London if Usain ran the 200-meter race in 19.32 seconds. If he ran 100 meters at that speed, By seeing the table given above would his 100 meter time is 9.63 seconds.
b. In the 4 × 100-meter relay, four runners each run a 100-meter leg. The Jamaican team ran the relay with a time of 36.84. If all four legs took the same amount of time to run, how long would one leg have taken?
Time of 9.21,
Explanation:
Given in the 4 × 100-meter relay, four runners each run a 100-meter leg. The Jamaican team ran the relay with a time of 36.84. If all four legs took the same amount of time to run long would one leg have taken is 36.84/4 = 9.21.
c. In practice, the first leg of a relay takes longer to run than the others because the first runner must start the race from a still position. If the first leg of the Jamaican team’s relay took 9.72 seconds of the total time, but the other 3 legs were all equal, what was the time for one of the later legs?
The time for one of the later legs is 9.04,
Explanation:
As in practice, the first leg of a relay takes longer to run than the others because the first runner must start the race from a still position. If the first leg of the Jamaican team’s relay took 9.72 seconds of the total time, but the other 3 legs were all equal the time for one of the later legs is (36.84 – 9.72)/3 = 27.12/3= 9.04 respectively.
Question 2.
Divide each number. Show your work.
9.6 ÷ 10 = ________________
9.6 ÷ 100 = ________________
16.08 ÷ 10 = ________________
16.08 ÷ 20 = _______________
132.22 ÷ 10 = _______________
132.22 ÷ 100 = ______________
78.2 ÷ 10 = ______________
78.2 ÷ 20 = ______________
9.6 ÷ 10 = 0.96,
9.6 ÷ 100 = 0.096,
16.08 ÷ 10 = 1.608,
16.08 ÷ 20 = 8.04,
132.22 ÷ 10 = 13.222,
132.22 ÷ 100 = 1.3222,
78.2 ÷ 10 = 7.82,
78.2 ÷ 20 = 3.91,
Explanation:
Divided the given numbers as 9.6 ÷ 10 = 0.96, 9.6 ÷ 100 = 0.096, 16.08 ÷ 10 = 1.608, 16.08 ÷ 20 = 8.04, 132.22 ÷ 10 = 13.222, 132.22 ÷ 100 = 1.3222, 78.2 ÷ 10 = 7.82, 78.2 ÷ 20 = 3.91 respectively.
Question 3.
Compare what happens to the quotient when you divide by 10 and by 100.
For 10 one place value to the left for 100 we move the decimal place two places to the left.,
Explanation:
The process for dividing by 100 is very similar to the one used when dividing by 10. Instead of moving the decimal point one place value to the left, we move the decimal place two places to the left.
Question 4.
Compare what happens to the quotient when you divide by 10 and by 20.
For 10 one place value to the left for 20 by 2 first then by 10,
Explanation:
When dividing by 10 moving the decimal point one place value to the left, dividing by 20 first we divide by 2 and then the obtained quotient is divided by 10 accordingly.
Question 5.
Kary and Val were solving the following problem: $12.55 ÷ 5. Kary wrote$25.10 as her answer. Val wrote $2.51. Who is right? How do you know? Answer: Val wrote correctly, by checking we know who is right, Explanation: Given Kary and Val were solving the following problem:$12.55 ÷ 5. Kary wrote $25.10 as her answer. Val wrote$2.51 upon checking
5)$12.55($2.51
10
2.55
2.50
0.05
0.05
0
So as answer is \$2.51 Val wrote correctly.
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http://mathhelpforum.com/calculus/25440-integral.html
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# Math Help - Integral
1. ## Integral
$\int \frac{1}{x^7-x}\;dx$
Thanks
2. There are various things tou can do. Partial fractions. Maybe just a small factoring and a sub.
$\int\frac{1}{x(x^{6}-1)}dx$
Let $u=x^{6}-1, \;\ du=6x^{5}dx, \;\ \frac{du}{6}=x^{5}dx, \;\ u+1=x^{6}$
This leads to $\frac{1}{6}\int\frac{1}{u^{2}+u}du$
$\frac{1}{6}\left[\int\frac{1}{u}du-\int\frac{1}{u+1}du\right]$
Now, continue?.
If you feel industrious, you could do the PFD thing.
$x^{7}-x = x(x+1)(x-1)(x^{2}+x+1)(x^{2}-x+1)$
3. How exactly does this: Let $u=x^{6}-1, \;\ du=6x^{5}dx, \;\ \frac{du}{6}=x^{5}dx, \;\ u+1=x^{6}$ lead to this:
$\frac{1}{6}\int\frac{1}{u^{2}+u}du$
thats the part i didn't understand, thats why i couldn't use subst. myself.
The aftermath is easy....
Originally Posted by galactus
If you feel industrious, you could do the PFD thing.
$x^{7}-x = x(x+1)(x-1)(x^{2}+x+1)(x^{2}-x+1)$
After i posted this, i actually solved it, but i did this before applying PF....the above would take to long...
$\int \frac{1}{x(x^3-1)(x^3+1)}=\frac{1}{2}\int \frac{(x^3+1)-(x^3-1)}{x(x^3-1)(x^3+1)}=\frac{1}{2}\int\frac{1}{x(x^3-1)}-\frac{1}{x(x^3+1)}$
4. Let's see
We want: $\int{\frac{dx}{x\cdot{(x^6-1)}}}$
Multiply and divide by $6\cdot{x^5}$ we get: $\int{\frac{6\cdot{x^5}}{6\cdot{x^6}\cdot{(x^6-1)}}}dx$
We now let: $u=x^6-1\rightarrow{\frac{du}{dx}=6\cdot{x^5}}$
Thus we have: $\int{\frac{du}{6\cdot{u}\cdot{(u+1)}}}=\frac{1}{6} \cdot{\int{\frac{du}{u\cdot{(u+1)}}}}$
5. Originally Posted by PaulRS
Multiply and divide by $6\cdot{x^5}$
That was the critical step i need to know!!
Thanks
6. Originally Posted by polymerase
$\int \frac{1}{x^7-x}\;dx$
You can also avoid substitutions
$\int {\frac{1}
{{x^7 - x}}\,dx} = \int {\frac{1}
{{x\left( {x^6 - 1} \right)}}\,dx} = \int {\frac{{x^6 - \left( {x^6 - 1} \right)}}
{{x\left( {x^6 - 1} \right)}}\,dx}$
.
So $\int {\frac{1}
{{x^7 - x}}\,dx} = \frac{1}
{6}\int {\frac{{\left( {x^6 - 1} \right)'}}
{{\left( {x^6 - 1} \right)}}\,dx} - \int {\frac{1}
{x}\,dx}$
.
The rest follows.
7. Hello, PaulRS!
That's brilliant! . . . Thank you!
8. Here's what I was getting at:
Because, $\frac{x^{5}}{x^{6}}=\frac{1}{x}$
Now, because $u=x^{6}-1, \;\ u+1=x^{6}, \;\ du=6x^{5}dx, \;\ \frac{du}{6}=x^{5}dx$
Rewrite as : $\frac{1}{6}\int\frac{x^{5}}{x^{6}(x^{6}-1)}dx$
Make the subs and we get:
$\frac{1}{6}\int\frac{1}{(u+1)u}du=\frac{1}{6}\int\ frac{1}{u^{2}+u}du$
See now?.
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https://www.gamedev.net/forums/topic/502919-linker-error/
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• ### What is your GameDev Story?
Public Group
This topic is 3824 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.
## Recommended Posts
##### Share on other sites
All this means is that the listed functions could not be found -- that usually means you either did not define them, misspelled a definition, or defined them but managed to exclude the file containing the definition from compilation.
The functions in question are:
CDlgAdvOptions::CDlgAdvOptionsCDlgAdvOptions::~CDlgAdvOptionsCSpeech::CSpeechCSpeech::~CSpeechCNetProApp::TalkCNetProApp::VoiceRecognitionCSpeech::Run
Do you have definitions for those functions? If so, show us.
##### Share on other sites
Quote:
Um, yes? There's not much anyone of us can add to this.
The linker can't find the symbols mentioned.
Cleaning them up a bit, a few of them seem to be:
CSpeech::CSpeech()
CSpeech::CSpeech(void)
I know linker errors look scary, but they can be deciphered, and there's no magic in them. It simply states the symbols that some of your object files reference, but which it can't find definitions of.
Since I have absolutely no clue what your CSpeech class does, much less how it is defined, or how you call the compiler, I can't tell you how to fix it.
• ### What is your GameDev Story?
In 2019 we are celebrating 20 years of GameDev.net! Share your GameDev Story with us.
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http://aas.org/archives/BAAS/v27n4/aas187/S108007.html
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Session 108 - HII Regions.
Display session, Thursday, January 18
North Banquet Hall, Convention Center
## [108.07] HST Parallel WFPC2 Imagery of a Region in the Carina Nebula
R. J. Dufour (Rice), D. VanOrsow (STScI), D. K. Walter (SCSU), J. J. Hester (ASU), D. G. Currie (U. MD)
As part of the HST General Observer Program GO-6042, parallel WFPC2 images of locations in the large Carina H \sc ii region were taken during a series of FOS spectra of several ejecta of Eta Carinae (cf., the poster by Glover et al. at this meeting). The observations were scheduled during two CVZ (continuous viewing zone) visits in 1995 October, enabling deep WFPC2 exposures to be taken in ten filters. The serendipitous'' target was an area which included the Cr 232 star cluster and surrounding H \sc ii region, about 8 arcmin to the NW of Eta Carinae itself. Images of the nebula were obtained in the filters F656N (H\alpha), F673N ([S \sc ii] 6717+31 ÅF658N ([N \sc ii] 6583 ÅF502N ([O \sc iii] 5007 Åand F547M (continuum) for puposes of studying the ionization structure. In addition, relatively long (\sim1000 sec) exposures were obtained though the wide-band filters F336W, F439W, and F555W for purposes of obtaining UBV magnitudes and colors of stars down to a limiting magnitude of V\sim25.
We present the results of this imagery in the form of (a) color-coded emission line ratio maps of the nebulosity in the various lines noted above, and (b) color-magnitude (CMD) and color-color diagrams of faint stars in the field. At a distance of 2500 pc for the nebula and cluster, the spatial resolution of 0.1 arcsec on the WFPC2 imagery corresponds to 250 AU per pixel, a scale that resolves numerous Bok globules not previously seen from ground-based imagery. These globules are seen in absorption in the [O \sc iii] images and with bright rims in [S \sc ii] and [N \sc ii], indicating their proximity to the cluster OB stars and location in the ionized volume of the nebula. Our CMDs, (very preliminary at the time of writing) reach M_V\sim+11 for stars at the distance of the Cr 232 cluster. A prominent reflection nebula is also seen around one of the stars in the cluster.
This study is made possible by grants from AURA/STScI related to GO-6042 and the HST Cycle 5 TAC, which supported our expectations regarding science that would result from the parallel imagery.
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http://mathhelpforum.com/algebra/154014-mult-imaginary-numbers.html
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Math Help - mult. imaginary numbers
1. mult. imaginary numbers
5 - 2i
3 + 8i
for this problem i would like to know if i should mult. both the tope and the bottom by
3 + 8i.
also i already know that (i) to the second power is equal to -1. but how would you work it out?
2. Originally Posted by allsmiles
5 - 2i
3 + 8i
for this problem i would like to know if i should mult. both the tope and the bottom by
3 + 8i.
also i already know that (i) to the second power is equal to -1. but how would you work it out?
multiply numerator and denominator by the conjugate of the denominator ... (3 - 8i)
3. Originally Posted by allsmiles
5 - 2i
3 + 8i
for this problem i would like to know if i should mult. both the tope and the bottom by
3 + 8i.
also i already know that (i) to the second power is equal to -1. but how would you work it out?
$\frac{5-2i}{3+8i} . \frac{3-8i}{3-8i}$
|
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https://toolslick.com/finance/interest/doubling-time
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# Doubling Time Calculator
Doubling Time Calculator is used to calculate the period of time required for an investment to double in size or value
Doubling Time:
..
Background Information
What does Doubling Time mean?
Doubling time is the period of time it takes for a value to double itself at a consistent rate of growth. This term is applied to any value that increases at a consistent rate.
Formula
Td = log(2) / log(1 + r)
Where:-
• Td = doubling time
• r = a constant growth rate
Example
Mr. Jacques earns 6% per year, compounded monthly. His monthly rate will be; r in the doubling time formula would be .005 (.06/12).
According to the formula,
Mr. Jacques would double his money within 138.98 months, or 11.58 years.
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https://www.math-only-math.com/roots-of-a-quadratic-equation.html
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# Roots of a Quadratic Equation
We will learn how to find the Roots of a quadratic equation.
Every quadratic equation gives two values of the unknown variable and these values are called roots of the equation.
Let ax$$^{2}$$ + bx + c = 0 be a quadratic equation. If aα$$^{2}$$ + bα + c = 0 then α is called a root of the quadratic equation ax$$^{2}$$ + bx + c = 0.
Thus,
α is a root of ax$$^{2}$$ + bx + c = 0 if and only if aα$$^{2}$$ + bα + c = 0
If aα$$^{2}$$ + bα + c = 0 then we say x = α satisfies the equation ax$$^{2}$$ + bx + c = 0 and x = α is a solution.
Thus, every solution is root.
A quadratic equation has two roots which may be unequal real numbers or equal real numbers, or numbers which are not real.
If a quadratic equation has two real equal roots α, we say the equation has only one real solution.
Example: Let 3x$$^{2}$$ + x - 2 = 0 be a quadratic equation. Clearly,
3 ∙ (-1)$$^{2}$$ + (-1) - 2 = 0
So, x = -1 is a root of the quadratic equation 3x$$^{2}$$ + x - 2 = 0.
Similarly, x = 2/3 is another root of the equation.
But x = 2 is not a root of 3x$$^{2}$$ + x - 2 = 0 because 3 ∙ 2$$^{2}$$ + 2 - 2 ≠ 0.
Solved examples to find the roots of a quadratic equation:
1. Without solving the quadratic equation 3x$$^{2}$$ - 2x - 1 = 0, find whether x = 1 is a solution (root) of this equation or not.
Solution:
Substituting x = 1 in the given equation 3x$$^{2}$$ - 2x - 1 = 0, we get
3(1)$$^{2}$$ - 2 (1) - 1 = 0
⟹ 3 - 2 - 1 = 0
⟹ 3 - 3 = 0; which is true.
Therefore, x = 1 is a solution of the given equation 3x$$^{2}$$ - 2x - 1 = 0
2. Without solving the quadratic equation x$$^{2}$$ - x + 1 = 0, find whether x = -1 is a root of this equation or not.
Solution:
Substituting x = -1 in the given equation x$$^{2}$$ - x + 1 = 0, we get
(-1)$$^{2}$$ - (-1) + 1 = 0
⟹ 1 + 1 + 1 = 0
⟹ 3 = 0; which is not true.
Therefore, x = -1 is not a solution of the given equation x$$^{2}$$ - x + 1 = 0.
3. If one root of the quadratic equation 2x$$^{2}$$ + ax - 6 = 0 is 2, find the value of a. Also, find the other root.
Solution:
Since, x = 2 is a root of the gives equation 2x$$^{2}$$ + ax - 6 = 0
⟹ 2(2)$$^{2}$$ + a × 2 - 6 = 0
⟹ 8 + 2a - 6 = 0
⟹ 2a + 2 = 0
⟹ 2a = -2
⟹ a = $$\frac{-2}{2}$$
⟹ a = -1
Therefore, the value of a = -1
Substituting a = -1, we get:
2x$$^{2}$$ + (-1)x - 6 = 0
⟹ 2x$$^{2}$$ - x - 6 = 0
⟹ 2x$$^{2}$$ - 4x + 3x - 6 = 0
⟹ 2x(x - 2) + 3(x - 2) = 0
⟹ (x - 2)(2x + 3) = 0
⟹ x - 2 = 0 or 2x + 3 = 0
i.e., x = 2 or x = -$$\frac{3}{2}$$
Therefore, the other root is -$$\frac{3}{2}$$.
4. Find the value of k for which x = 2 is a root (solution) of equation kx$$^{2}$$ + 2x - 3 = 0.
Solution:
Substituting x = 2 in the given equation kx$$^{2}$$ + 2x - 3 = 0; we get:
K(2)$$^{2}$$ + 2 × 2 - 3 = 0
⟹ 4k + 4 - 3 = 0
⟹ 4k + 1 =
⟹ 4k = -1
⟹ k = -$$\frac{1}{4}$$
Therefore, the value of k = -$$\frac{1}{4}$$
Formation of Quadratic Equation in One Variable
Word Problems on Quadratic Equations by Factoring
Worksheet on Formation of Quadratic Equation in One Variable
Worksheet on Nature of the Roots of a Quadratic Equation
Worksheet on Word Problems on Quadratic Equations by Factoring
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https://zenodo.org/record/3358134
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There is a newer version of this record available.
Software Open Access
sherpa/sherpa: Sherpa 4.11.1
Doug Burke; Omar Laurino; dtnguyen2; Jamie Budynkiewicz; Tom Aldcroft; Aneta Siemiginowska; Christoph Deil; wmclaugh; Brigitta Sipocz; Katrin Leinweber
Sherpa 4.11.1
This release of Sherpa introduces several functional improvements and bug fixes, in particular Sherpa now has support for:
• asymmetric error bars
• PSFs with better pixel resolution than the data
• running optimization in parallel
Details 630 Fix "get_int_proj does not work when recalc=True" (#543)
get_int_proj did not work when recalc=True on Python 3. This has now been fixed.
615 Asymmetric Errors
Sherpa now supports asymmetric error bars. Errors can be read through a new
load_ascii_with_errors high level function, or through the new Data1DAsymmetricErrs class. Sherpa uses bootstrap for estimating the uncertainties.
585 plot pvalue
Updates to utilize the appropriate response files (ARF and RMF) for X-ray spectra
and changes to the p_value output to 1/(number of simulations) when p_value is 0
and the number of simulations in not large enough.
596 Run optimization algorithms over multiple cores
This PR enables the user to run the optimization algorithms (DifEvo, LevMar,
607 PSF rebinning (fix #43)
Sherpa now supports using a PSF with a finer resolution than 2D images. If Sherpa
detects that the PSF has a smaller pixel size than the data, it will evaluate the model on a "PSF Space" that has the same resolution as the PSF and the same footprint as the data, then rebin the evaluated model back to the data space for calculating the statistic.
614 Refactor data classes (fix #563, #627, #628)
Sherpa's basic data classes have been refactored and cleaned up to help
facilitating fixing bugs and implementing new features. New tests were added to reduce the chances of introducing regressions in the future.
612 Fix #609 User Model: unable to change parameter values
A regression introduced in Sherpa 4.10.0 presented users from change
user-model parameter values through direct access. This issue has been fixed. Several tests were added to reduce the chance of regressions in the future.
Fix #514 - the command line tool sherpa_smoke in the conda package now correctly honors command line arguments.
Files (13.8 MB)
Name Size
sherpa/sherpa-4.11.1.zip
md5:6965e10171eb8e2e975f5c21a3f32ff3
13.8 MB
1,848
89
views
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http://math.stackexchange.com/users/62427/user62427?tab=reputation
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user62427
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# 111 Reputation
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+5 11:23 upvote In how many ways we can place $N$ mutually non-attacking knights on an $M \times M$ chessboard?
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-2 00:15 downvote In how many ways we can place $N$ mutually non-attacking knights on an $M \times M$ chessboard?
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+5 07:49 upvote In how many ways we can place $N$ mutually non-attacking knights on an $M \times M$ chessboard?
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https://www.physicsforums.com/threads/lc-circuit-with-variable-capacitor.525124/
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# LC circuit with variable capacitor
1. Aug 28, 2011
### Piano man
1. The problem statement, all variables and given/known data
A constant voltage at a frequency of 1MHz is maintained across a circuit consisting of an inductor in series with a variable capacitor. When the capacitor is reduced from 300pF to 284pF, the current is 0.707 of its maximum value. Find
(i) the inductance and the resistance of the inductor, and
(ii) the Q factor of the inductor at 1MHz. Sketch the phasor diagram for each condition.
2. Relevant equations
$$\omega=\frac{1}{\sqrt{LC}} // v_L=L\frac{di}{dt} // v_C=\frac{q}{C}$$
Probably a load of other formulae as well.
3. The attempt at a solution
Using Kirchoff, get $$L\frac{di}{dt} + \frac{q}{300*10^{-12}}=0$$ for the first case and $$0.707L\frac{di}{dt}+\frac{0.707it}{284*10^{-12}}=0$$ for the second.
Equating the two, I'm still left with i and t and a feeling that I'm barking up the wrong tree.
Any help would be appreciated - it's ages since I've done these type of questions.
Thanks.
2. Aug 28, 2011
### Spinnor
Do you take into account the voltage generated by the resistance of the inductor?
Last edited: Aug 28, 2011
3. Sep 1, 2011
### rude man
Unfortunately, this problem as stated gives insufficient info.
As a matter of fact, one solution is Q = infinity, L = (√2/wC1 - 1/wC2)/w(√2-1) H
where C1 = 300 pF, C2 = 284pF, R = 0 and w = 2pi*1 MHz.
As Spinnor indicates, the same conditions can obtain when R (and therefore Q) are finite. What has to be specified in addition to the above is the phase of the current i0/√2. I happen to have picked 180 deg. I suppose one could object that I went from 0 to 180 which is -0.707i0 but remember if the detuning is to be ascribed to a finite Q, i0/√2 is not in phase with i0 either .... out 45 deg in fact.
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Similar Discussions: LC circuit with variable capacitor
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http://www.transtutors.com/questions/a-downward-force-of-8-4n-is-exerted-on-a-8-8-956-c-charge-wha-423245.htm
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+1.617.933.5480
# Q: A downward force of 8.4N is exerted on a -8.8μC charge. Wha
A downward force of 8.4N is exerted on a -8.8μC charge. What are the magnitude and direction of the electric field at this point?
Given Data force acting is F = 8.4N...
Related Questions in Electromagnetic Theory
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https://quant.stackexchange.com/questions/31136/is-value-at-risk-additive
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# Is Value At Risk additive?
I have computed the value at risk of 2 different commodities.
Assuming they have not correlated, can I just sum the two standalone VaR to get my overall portfolio's VaR ?
• I have VAR for commodity 1 and VAR for commodity 2. Nov 23 '16 at 0:48
• What do you mean? Do you want to compute the VaR of holding 1 unit of both commodities?
– SRKX
Nov 23 '16 at 1:15
• Yes var of holding both Nov 23 '16 at 1:16
The answer to your question is no. Value at Risk is not additive in the sense that $\text{VaR}(X+Y) \neq \text{VaR}(X) + \text{VaR}(Y)$. But I guess your question is more to aimed at finding a formula for your investments than to look at the property itself.
I think the only way to get a nice formula for this is to assume that both assets are:
• Normally distributed
• Have a mean equal to 0
• Are independent
Closed-Form value at risk for Normal variable
Mathematically the Value at Risk at a given level $\alpha$ is defined as:
$$\text{VaR}_\alpha(X) = \{ y ~ | ~ \mathbb{P}( X\leq y) = \alpha \}$$
If you can assume you variable $X$ is normally distributed such that $X \sim \mathcal{N}(\mu, \sigma^2)$, then you can re-express $X$ in terms of another variable $Z \sim \mathcal{N}(0,1)$: $X = \mu + \sigma Z$.
Using this, we know can rewrite the VaR definition as:
\begin{align} \text{VaR}_\alpha(X) &= \{ y ~ | ~ \mathbb{P}( \mu + Z\sigma\leq y) = \alpha\}\\ &= \left\{ y ~ | ~ \mathbb{P}\left( Z \leq \frac{ y- \mu}{\sigma} \right) = \alpha \right\}\\ &= \left\{ y ~ | ~ \Phi\left( \frac{ y- \mu}{\sigma} \right) = \alpha \right\}\\ \end{align}
where $\Phi(x)$ is the cumulative normal standard distribution function.
We can then find a closed-form formula to the value at risk of a normally distributed variable $X$:
$$\text{VaR}_\alpha(X) = \Phi^{-1}(\alpha) \cdot\sigma + \mu$$
Distribution of portfolio of two Normal variables
Now, let's assume you portfolio $Y$ holds two assets $X_1$ and $X_2$ (the two commodities in your example), which are uncorrelated ($\rho = 0$).
If you assume that both are normally distributed $X_1 \sim \mathcal{N}(\mu_1,\sigma_1)$ and $X_2 \sim \mathcal{N}(\mu_2,\sigma_2)$, then the we know that the portfolio can be expressed as:
\begin{align} Y &= wX_1 + (1-w)X_2\\ &= w(\mu_1 + \sigma_1 Z_1) + (1-w)(\mu_2 +\sigma_2 Z_2)\\ &= w\mu_1 + (1-w) \mu_2 + w\sigma_1 + w \sigma_1 Z_1 + (1-w) \sigma_2 Z_2 \end{align}
Hence, we know that:
$$\mathbb{E}(Y) = w\mu_1 + (1-w) \mu_2$$
and
$$\text{Variance}(Y) = \sigma_Y^2 = w^2 \sigma_1^2 + (1-w)^2 \sigma_2^2$$
because you assets are independent.
As we know, the sum of 2 normally distributed variables is also normally distributed, hence: $$Y \sim \mathcal{N}(w\mu_1 + (1-w) \mu_2, w^2 \sigma_1^2 + (1-w)^2 \sigma_2^2)$$
Value-at-risk of the portfolio
Using the formula for value-at-risk for normal variable we found above, we can write:
\begin{align} \text{VaR}_\alpha(Y) &= \Phi^-1(\alpha) \sigma_Y + \mu_y\\ \text{VaR}_\alpha(Y) &= \Phi^-1(\alpha) \sqrt{w^2 \sigma_1^2 + (1-w)^2 \sigma_2^2} + w\mu_1 + (1-w) \mu_2\\ \end{align}
If you assume that $\mu_1 = \mu_2 = 0$, then you get:
\begin{align} \text{VaR}_\alpha(Y) &= \Phi^-1(\alpha) \sqrt{w^2 \sigma_1^2 + (1-w)^2 \sigma_2^2}\\ \text{VaR}_\alpha(Y)^2 &= \Phi^-1(\alpha)^2 (w^2 \sigma_1^2 + (1-w)^2 \sigma_2^2)\\ \text{VaR}_\alpha(Y)^2 &= \Phi^-1(\alpha)^2 w^2 \sigma_1^2 + \Phi^-1(\alpha)^2 (1-w)^2 \sigma_2^2\\ \text{VaR}_\alpha(Y)^2 &= w^2 \text{VaR}_\alpha(X_1)^2 + (1-w)^2 \text{VaR}_\alpha(X_2)^2\\ \text{VaR}_\alpha(Y) &=\sqrt{ w^2 \text{VaR}_\alpha(X_1)^2 + (1-w)^2 \text{VaR}_\alpha(X_2)^2}\\ \end{align}
• Normal distribution is very rare situation in practice. Is it possible to extend your answer to general case?
– Nick
Nov 23 '16 at 7:23
• @Nick general case has no simple closed-form solution; it would depend on the joint distribution of the assets.
– SRKX
Nov 23 '16 at 7:36
• what is "w" in the above? Nov 23 '16 at 12:58
• I'm guessing w is weight of % of each i own Nov 23 '16 at 13:04
• Yes that's correct. And you VaR is expressed as a percentage of your initial wealth.
– SRKX
Nov 23 '16 at 14:10
You need to square them, add the squares , and take the square root. (Variances are additive, not standard deviations).
• VAR is the abbreviation of variation, VaR is the abbreviation value at risk. In the title you wrote value at risk, in the body you used VAR. What did you mean?
– Nick
Nov 23 '16 at 3:37
• Value at risk yes. Sorry about abbreviation. Value at risk in title. Nov 23 '16 at 4:35
• @Nick I think VAR is more commonly used as Vector AutoRegression, though. Nov 23 '16 at 8:31
Well, if you are using historical VaR, you can add results on each scenario and then calculate percentile of results... There is no other way.
No, because the value at risk is not, in general, a coherent risk measure as it does not respect the sub-additivity property, i.e.
$\rho(X + Y) \ne \rho(X) + \rho(Y)$, $\forall X, Y \in \mathcal{X}$ for the $VaR$.
However, Conditional Value at Risk is. Check out Is Conditional Value-at-Risk (CVaR) coherent?
• This is only showing it would not work in all cases, but you don't show why it couldn't work under certain assumption (here $\rho=0$).
– SRKX
Nov 23 '16 at 5:49
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http://bicycles.stackexchange.com/questions/16253/why-arent-average-speeds-computed-over-distance/16256
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# Why aren't average speeds computed over distance?
Average speed is computed so that average speed = total distance / total time. This means that if you go up a hill, which takes a long time, your average speed drops. This isn't regained on the downhill, since going down takes so much less time.
If you compute the average over distance instead (i.e., your speed every tenth of a mile), the uphill and downhill are equally weighted, since they have the same number of samples. This means that your average is closer to what your speed would be on flat ground.
Your speed over flat ground seems more important to me. It doesn't depend on how hilly your route is, and that way you could compare cyclists more easily. Why don't we compute the average speed over distance instead?
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Because that's the way it's done. Simple and easy to understand. You can always compute it the other way if you wish -- just learn how to program an Android. – Daniel R Hicks Jun 15 '13 at 20:41
I don't understand what you mean by computing it over distance. Could you give an example of what that equation would look like? – jimirings Jun 15 '13 at 21:07
@jimirings One useful definition: calculate the average pace and then calculate its reciprocal – anatolyg Jun 16 '13 at 21:33
To me, this would make sense in case of speeders in traffic, because the road dangers appear relative to distance and not to time. So if some bloke flies through an all-through-dangerous town, you wouldn't say anymore that he was causing danger for the very little time he was coming past the town, but that he actually caused danger all along the road. So speeders would get a more appropriate judgement. – Sam Sep 3 '14 at 21:15
Except you do regain it on the downhill, because you cover a great distance in a short amount of time. – whatsisname Sep 7 '14 at 19:22
This is an interesting point of view. Let's unpack this a bit.
Assume I have a ride that is 10 miles of flat, 10 miles of ascent, and 10 miles of descent.
On the flat I maintain a constant 20 miles/hour.
On the ascent I fall back to a constant 10 miles/hour.
On the descent I maintain a constant 30 miles/hour.
My average speed for this would be:
(10 miles + 10 miles + 10 miles) / (0.5 hour + 1.0 hour + .33 hour) = 16.39 miles/hour
By the proposed calculation I would have:
(100 tenths/mile * 20 miles/hour + 100 tenths/mile * 10 miles/hour + 100 tenths/mile * 30 miles/hour) / 300 tenths/mile = 20 miles/hour
If I had an average of 20 mph I should be able to complete the course in 1.5 hours. The trouble is that the course would actually take 1.83 hours to complete at the actual average of 16.39 mph. I know it hardly seems fair, since by all rights you did the vast majority of miles at 20+ mph. The caveat is that you spent by far the greatest amount of time at 10 mph.
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+1 because mathematics is always right. – Carey Gregory Jun 15 '13 at 22:59
Can you always assume that your speed difference is the same for uphill and downhill? You can say that the force is always the same (mgsin(theta)), but there's also wind resistance (and other factors, I'm willing to bet) to factor in. – Scott Jun 15 '13 at 23:05
@Scott - The speed difference could be the same, but the rider's power output could vary substantially in relation to a number of factors. The best metric is probably WTHarper's suggestion of work/distance or work/time. See the graph of resistance and velocity in their post. – Craig Bennett Jun 15 '13 at 23:23
@Scott - You definitely cannot assume that the speed difference is the same going up vs down. Likely nowhere close. I may average 15 mph on the flat, hit 30 going down a given hill, without even pedaling, and go up that same hill at 6 mph. And consider that, as a hill gets steeper, the uphill speed will eventually reach zero (ie, the cyclist simply cannot climb that hill). But downhill speed can easily exceed 50 mph. – Daniel R Hicks Jun 16 '13 at 1:53
This isn't worth adding another answer for, but speed is defined as the derivative of distance with respect to time: dx/dt. The average speed is almost the same formula: (end_x - start_x) / (end_t - start_t). No good can come from redefining well accepted mathematical definitions. – amcnabb Jun 16 '13 at 13:56
Your average speed is always going to be a measure of distance over a period of time. What I think you're trying to get at is accounting for your grade losses (i.e. riding up a hill), but it would be equally pertinent to include losses for wind resistance and friction as well. This would allow you to determine the amount of work per distance (or per time) for the trip, but calculating all of the variables which would verify your actual work is impractical for the average cyclist.
Products like Power Tap hubs allow you to generate torque and cadence data from your rides. That information would give you better insight into your speed with regards to sustained torque and cadence and it will also better illustrate where total resistance is increased or decreased (e.g. going up or down a hill.)
As far as taking average speed over a set distance, you're still averaging. It doesn't matter if your sample is 0.1 miles or 10 kilometers, it is still a measure of distance per time.
Here is some more information on calculating propulsion resistance. I don't remember how to do much calculus, but it is there for anyone better equipped.
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+1 for identifying average power as the measure that the poster is looking for. – amcnabb Jun 16 '13 at 13:49
The main issue with what you're talking about is that from a mathematical perspective, 'average' already has a strict meaning, and in this context nearly always means 'arithmetic mean'.
https://en.wikipedia.org/wiki/Average
If you want to talk about another measure of speed, you have to drop the term 'average speed' at the very least. What your method seems to be referring to would be something like the average of multiple constant interval average speeds, and as such two people both reporting their AoMCIAS could vary wildly, even if they traveled side-by-side.
For example, why pick tenths of a mile? There are infinite variants of division lengths unit choices such that two AoMCIAS numbers can't even be related (unless the distance has been mutually agreed upon before measurement collection). Good luck getting the U.S. to adopt the metric system or the rest of the world to adopt Imperial units, so at minimum you'd have U.S. bicyclists reporting it over 0.1 mile intervals and everyone else at, perhaps, 0.2 km intervals.
For that matter, why use length as the interval control? If you use a GPS, it's storing the data in semi-regular interval time units (depending on the unit and resolution setting), perhaps someone else tries to unify the U.S. with the rest of the world and proposes 10 second intervals as the new standard.
The result is that AoMCIAS speed numbers would not convey enough information in and of their own value, like averages do. You'd have to report them as "24.56 miles/hour AoMCIAS over 0.1 mile intervals", and that value would vary so wildly by interval choice that it could ONLY be compared to other AoMCIAS speeds with the exact same interval. There wouldn't be a static conversion that could be done, either, you would need to completely resample the intervals from raw data, if it was even available.
All of this is completely independent of it's relevance as a speed measure for bicycling (I have a mathematics degree, and don't time any of my bicycle rides). What I mean by this is: it's possible that you could devise a creative method such as AoMCIAS with an ideal interval distance or time such that the number reflects something more accurate about bicycling performance, and it may even be useful inside of the bicycling context (and likely ONLY the bicycling context). However, it will be of little to no value to anyone else, mathematically or even quick comparison-wise in colloquial speech. Two numbers could only really compared with equivalent intervals, and any ability to do neat things quickly in your head with such values would be relegated to special calculators, computer programs, and perhaps some genius savants.
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You cant't compare it - that's a good reason. – Uooo Jun 19 '13 at 8:25
By computing your average speed over a distance, you basically sample the distance (delta S) and measure the time (t_i) each time you reach the defined sampling distance. The formula then to compute your average speed would be:
Then the problem starts. By decreasing your sampling distance as previously proposed to increase your "accuracy", you will reduce the time difference (t_i - t_(i-1) ). Let say you decrease your sampling distance towards zero, your time difference will tend towards 0 to... Which lead to a mathematical problem of 0/0, which is undetermined... The only correct average speed you can get from this formula is by choosing your sampling distance to the complete distance of your ride. You have then only one sample (n=1) and t_0 is your start time and t_1 your end time.
But if you want to "mathematically" increase your average speed, then you can apply this formula and chose a sampling distance which corresponds to your wish.
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+1 Well put! This is indeed the right answer – Javier Jun 19 '13 at 18:55
Calculating the average speed after a tour is easy. You know the start time, the end time, and the length of your route. Therefore, you can find out the average speed.
Using "average over distance" approach: What if your track is so hilly that calculating every 10th of a mile is useless again? Then we would need to use every 100th of a mile. This will get more accurate, but will not be exact.
You could use a unit like "speed per meter". You would have to track the average speed of every meter then, which will be extremely difficult (even with assistance of a bike computer/smartphone). Still, every meter is an average speed, so, mathematically seen, it is still not exact. You would need the speed of an infinite small part of a meter to get the exact speed, which is impossible.
So, from my point of view, it is not done for two reasons:
1. Difficult to track
2. Mathematically incorrect
However, you can calculate anything the way you want. We will not tell anyone ;-)
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There are other, non-exacting ways to go about this, and they're used often in devices like GPSes. They receive and store point data - latitude, longitude, elevation and time in chunks as fine or course as your unit and settings specify. From this, you can get "speed between each point", and is one way they can use to calculate the total average, though the intervals are spaced by time units and not distance. For these devices it is both easy to track and mathematically as accurate as your device is calibrated to. – Ehryk Jun 19 '13 at 8:19
@Ehryk as accurate as your device is calibrated - of course you can do that. But the device limits the accurateness (although it is still very exact). The question was Why aren't average speeds computed over distance? (in general), and this are the reasons I can think of. Nothing blocks you from calculating it differently, if you want to. – Uooo Jun 19 '13 at 8:22
Agreed, I just wanted to add that the points you have apply more to human tracking, and aren't much of a factor to modern electronics. – Ehryk Jun 19 '13 at 8:25
This is really a statistics / maths question rather than a bicycles question.
I think the sum you are proposing would be closer to the median speed than the mean (average). There are 3 key statistical measures that can all be useful:
Mean or average in the case of speed would be distance/time.
Let's say we take the average speed over every 1 minute over a 60 min ride, the median is the speed at which 30 of the samples are below the median and 30 are above.
The Mode is the most commonly occurring average speed.
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A statistic is a just a mathematical tool for summarizing data so as to answer a particular question (or set of questions).
The usual definition of average speed relates time and distance, and helps to answer questions which crop up regularly in practice: "how long will it take me to get home?" "can I make it to the café before it closes?" "do I need to take lights on this ride?"
It's not clear to me that there are any practical questions that your statistic helps to answer.
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It would at least likely match the algorithm used within Expresso exercise bikes when stating the speed of the "pacer". – Daniel R Hicks Jun 21 '13 at 1:03
Exactly. When we have a set of different data we can simplify by replacing them all with the average and still get the same result in some calculation that we care about. If someone travels at various speeds on a route we can simplify by replacing each speed with the average speed and we still get the same duration. – bdsl Jan 19 at 17:40
Indeed your average speed is total distance over total time
Regarding sampling this is where you go wrong:
"If you compute the average over distance instead (i.e., your speed every tenth of a mile), the uphill and downhill are equally weighted."
No they are not equally weighted. The denominator is time (not distance). You need to take even samples in time. You cannot sample on distance if you want to average the sample.
20 miles up the hill and 20 miles down the hill.
Up assume 10 mph and down assume 30 mph.
First total distance over total time
Total distance is 40 miles
Total time is 20 miles / 10 mph + 20 miles / 30 mph = 2 hour up + 2/3 hour down = 8/3 hour
Average speed = total distance over total time = 40 miles / 8/3 hours = 120 / 8 mph
= 15 mph
The average speed is not the 10 + 30 / 2 = 20 mph because spent more time at 10 mph. Spent 3 times as long at 10 mph compared to 30 mph.
If you sampled every mile then indeed you would get the wrong answer of 15 mph average.
But if you sampled every minute you would get the right answer.
Up the hill you would have 120 samples at 10 mph and down the hill you 40 samples at 30 mph.
(120 * 10) + (40 * 30) / 120 + 40 = 1200 + 1200 / 160 = 240 / 16 = 15.
If you want to average the sample then the sample needs to based on the denominator.
But it is easier to just use total time over total distance.
If you had a magic hill that was 10 miles up and 30 miles down then your average speed would be the average as you would spend the same amount of time going up as down.
You can use any number you want for up versus down the hill. 18 mph up and 20 mph down. The average speed will not be speed up + speed down / 2. Because you will spend more time at the lower speed.
Average speed is caluculation:
d is total distance
su is speed up and sd is speed down
total distance / total time
d / (d / 2*su + d / 2*sd)
d / ( sd*d/2*su*sd + su*d/2*sd*su )
d / ( (sd*d + su*d) / 2*sd*su ) d*2*sd*du / d(su + sd)
2*sd*su / (su + sd)
hill same distance up as down
average speed = 2*sd*su / (su + sd)
in statistics it is called the harmonic mean
try 10 and 30 and get 15
try 20 and 20 and get 20
try 18 and 20 and get 19.95
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https://cs.stackexchange.com/questions/104126/what-does-it-mean-to-take-a-union-of-a-transition-function-with-a-starting-state
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# What does it mean to take a union of a transition function with a starting state?
$$\delta(q,a) = \begin{cases} \delta_1(q,a) & q \notin F_1 \text{ or } a \neq \lambda \\ \delta_1(q,a) \cup \{q_1\} & q \in F_1 \text{ and } a = \lambda. \end{cases}$$
Look at the second line of the function definition. It's a transition function. $$q_1$$ is the starting state. What does that union mean here? Union of the function range with $$\{q_1\}$$?
The function $$\delta_1$$ is the transition function of an NFA. It outputs a set of states. So $$\delta_1(q,a) \cup \{q_1\}$$ is just the union of two sets of states.
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https://stats.stackexchange.com/questions/468829/interpretation-lmer-output-with-interaction
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# Interpretation lmer output with interaction
I have performed this model:
M1 <- lmer(RNA_V ~ time + GENDER + time:GENDER + (time | PATIENT), df, REML=T)
I need to know if the two genders have different viral decay (relation between time and RNA in a longitudinal dataframe with several RNA inputs and times for each subject.
The results were:
Considering that the association with time and RNA is negative (with more time elapsed, less RNA). The gender==2 condition increases the effect of this association 0.07 times? (almost significant p=0.058). So, the gender==2 presented sharper viral decay curve (more negative), am I right?
• time = -0.16462 denotes how much the average RNA viral load changes (here decreases) with unit of time for subjects with GENDER = 1.
• GENDER2 = -0.32416 denotes the difference in average RNA viral loads between subjects with GENDER = 2 and GENDER = 1.
• time:GENDER2 = 0.07643 denotes the difference between subjects with GENDER = 2 and GENDER = 1 in the average change of RNA viral load per unit of time. That is, the average RNA viral load changes with time + time:GENDER2 = - 0.16462 + 0.07643 per unit of time for subjects with GENDER = 2.
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https://link.springer.com/article/10.1007/s10750-009-9791-z
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Hydrobiologia
, Volume 630, Issue 1, pp 187–197
# Effects of travertine and flow on leaf retention in Fossil Creek, Arizona
• Zacchaeus G. Compson
• Jane C. Marks
Primary research paper
DOI: 10.1007/s10750-009-9791-z
Compson, Z.G., Mier, M.Z. & Marks, J.C. Hydrobiologia (2009) 630: 187. doi:10.1007/s10750-009-9791-z
## Abstract
Leaf retention is important in transferring energy from riparian trees to stream food webs. Retention increases with geomorphic complexity such as substrate coarseness, sinuosity, and the presence of debris dams. High discharge can reduce retention, particularly when streams lack physical trapping features. Travertine formations, caused by calcium carbonate deposition, can alter stream morphology. To date, however, we know of no study testing the effect of travertine on leaf retention. This study capitalized on a river restoration project in Fossil Creek, Arizona, where water was returned to the channel after a century of diversion. We examined how the fixed factors Flow (before and after restoration) and Morphology (travertine and riffle-pool sites) affected leaf retention. Leaf retention was higher in sites where travertine forms barriers across the river, relative to sites with riffle-pool morphology. Most leaves retained in travertine reaches were concentrated at the bottom of pools formed between dams. Although flow restoration did not alter retention rates across all sites, it diminished them at travertine sites, indicating an interaction between stream flow and morphology. We conclude that stream complexity and leaf retention are enhanced by travertine deposition but that high discharge can reduce the retentive capacity of in-stream structures.
### Keywords
Leaf retention Flow restoration Travertine CPOM Fossil Creek
## Authors and Affiliations
• Zacchaeus G. Compson
• 1
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https://us.sofatutor.com/mathematics/videos/order-of-operations
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# Order of Operations
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The author
Susan Sayfan
## DescriptionOrder of Operations
The order of operations (operator precedence) helps you with simplifying expressions or equations.
Maybe you wonder what you should do first: calculation inside the parantheses (brackets), or solving exponents (indices, powers, orders) and square roots (radicals)? And what about multiplication, division, addition, and subtraction? Do you multiply numbers first before you add? And in what order do you divide or subtract?
The order of operations gives you easy instructions of which operator has precendence if you have to handle expressions and equations. A mnemonic device for the order of operations is the acronym PEMDAS (BODMAS, BEDMAS, BIDMAS). To memorize it better you can make a sentence with those letters, such as "Please Excuse My Dear Aunt Sally."
In math, as well as in real-life situations, the order of operations is a necessary tool for all basic calculations and it is very easy to follow. You will need it for every following math topic, as well as in many science topics and in everyday life.
This video shows you situations that are common in daily life where order is relevant and shows you step by step how to transfer this knowledge into math. You will learn the precendence of operators in a funny, entertaining way, and will be guided through simplifying complex expressions the easy way. After watching this video, you will forever remember the right order of operations as you connect it with a great mnemonic device.
Write expressions in equivalent forms to solve problems. CCSS.MATH.CONTENT.HSA.SSE.B.3
### TranscriptOrder of Operations
The Order of Operations. The ORDER of OPERATIONS! Yesterday, my dear Aunt Sally did everything in the wrong order. Look, she put her underpants above her skirt! She sent us to school. Then, she made our breakfast after we left. Later she baked cookies, but added the eggs in after the cookies came out.
My dear Aunt Sally did everything in the wrong order! As you can see, order is very important in everyday life. It is also important in math. Solving math problems is like following a recipe. You must follow the recipe for the Order of Operations, or PEMDAS to simplify expressions.
### Steps in PEMDAS
• The first step in the Order of Operations is P for Parentheses. All expressions inside the parentheses should be evaluated first.
• E stands for Exponents. Exponents should be evaluated second.
• The next step is M and D, which stands for Multiplication and Division. After parentheses and exponents have been evaluated you should multiply and divide.
• Finally A and S means Addition and Subtraction. They represent the last step in the Order of Operations. The rule about solving left to right also applies to Addition and Subtraction.
Ok let’s evaluate some expressions. We’ll start with an easy one. You will see that following PEMDAS will always lead us to the right answer!
### Calculation Example 1 & 2 using PEMDAS
First let’s look at two similar expressions: 8 - 2 + 5 and 8 – (2 + 5). The only difference between them is the use of parentheses. The first expression only has addition and subtraction so you should perform the operation in order from left to right: 8 − 2 = 6 and 6 + 5 = 11.
The second expression has parentheses. In PEMDAS the P for parentheses comes first. So, the Order of Operations tells you to evaluate the inside of the parentheses first: 2 + 5 = 7 and 8 − 7 = 1. Although these problems seem similar. They have two different answers.
### Calculation Example 3 using PEMDAS
Okay, let's try a harder problem. This one has parentheses, exponents, addition, and subtraction! Parentheses come first. 8 − 2 gives you 6 and 5 + 2 gives you 7. Next comes Exponents: 6² = 36. Finally, you add 36 + 7 = 43.
### Calculation Example 4 using PEMDAS
Now it's time to get even more tricky! Look at how many operations we are using! This expression has Parentheses, Exponents, Multiplication, Division, Addition, AND subtraction!
First you should be looking at the Parentheses. Inside you have 8 ÷ 2 − 2. Once inside the parentheses you have to use PEMDAS again. Division comes before subtraction so you must divide 8 by 2 before subtracting 2. Now you have 4 − 2. Resulting in 2. In the other parentheses you must evaluate the exponent before adding. You will need to square 5 before adding 2: 5² = 25, 25 + 2 will leave us with 27.
This problem is already looking better since we have taken care of the parentheses. The next step is E for exponents. 2 cubed gives you 8. Now we do multiplcation and division moving from left to right: 4 · 8 = 32 and 27 ÷ 9 = 3. The last step is Addition! 32 + 3 = 35. See? We started with this big expression, but by following the rules of PEMDAS we are able to simplify the expression to get 35!
### PEMDAS Mnemonic
No matter how difficult the expression looks: Simply follow PEMDAS to get things done! You can remember PEMDAS with this sentence: Please excuse my dear Aunt Sally! So, please excuse my dear Aunt Sally. She was a little bit confused yesterday.
## Order of Operations Exercise
Would you like to practice what you’ve just learned? Practice problems for this video Order of Operations help you practice and recap your knowledge.
• ### Using the correct order of operations, determine the right recipe.
Hints
The expressions $8 - 2 + 5$ and $8 - (2 + 5)$ seem similar. The only difference is the use of parentheses.
The first expression $8 - 2 + 5$ equals $11$. The second has the result $8 - (2 + 5) = 1$.
The last step is Addition & Subtraction. Always solve the equation from left to right.
Solution
As you know, order is a very important matter in everyday life.
You might be wondering why we need an order of operations in math, too.
If the Order of Operations didn't exist, we wouldn't be sure which operation to do first...and this could have a large effect on the answer.
What kind of operations are covered in the Order of Operations?
• Parentheses
• Exponents
• Multiplication & Division
As you can see, we have combined the operations Multiplication & Division into one step and Addition & Subtraction into another. If only Multiplication and Division remain to be solved (no Addition or Subtraction), it is very important to perform the operations in the order they appear from left to right.
By taking the first letter of each of our operations, we get PEMDAS - this way you will never forget the correct Order of Operations again!
• ### Correctly simplify the expression $(8 - 2)^2 + (5 + 2)$.
Hints
When you have simplified parentheses to a single number, you do not have to continue to write the parentheses.
Remember PEMDAS when evaluating the expressions.
Parentheses and Exponents come before Addition & Subtraction.
Solution
We want to simplify the expression $(8 - 2)^2 + (5 + 2)$. At first, it's helpful to recognize which operations are included in our expression. We can see:
• two sets of parentheses
• one exponent
• and subtraction
As we know, it's very important to evaluate the expression in the correct order. PEMDAS tells us how to evaluate the expression correctly. We simply have to follow the Order of Operations to arrive at the correct answer:
1. Parentheses
2. Exponents
3. Multiplication & Division
We take a look at the parentheses first. We can simplify the first parentheses from $(8 - 2)$ to $6$ and the second parentheses from $(5 + 2)$ to $7$, leaving us with $6^2+7$. As you can see, we have left out the parentheses. We can do that because we do not need them anymore.
Now, we can simplify the exponent: $6^2 + 7 = 36 + 7$. Finally, we add the remaining numbers, leaving us with $36 + 7 = 43$.
• ### Correctly simplify the expression and help Timothy figure out Sarah's number.
Hints
You can evaluate this expression by following the rules of PEMDAS.
When evaluating Multiplication & Division or Addition & Subtraction you must evaluate the operations in the order they appear in the equation from left to right.
Solution
Sarah had a cool idea. By encoding the last digits of her number, she has given Timothy a really difficult challenge.
But she didn't know that Timothy would be able to follow the rules of PEMDAS. He was able to simplify the expressions and find out the last three digits!
This is what he evaluated:
$\begin{array}{rcl} (2 \times 3)^2+1+800-(14-10)^2 & \overset{P}{=} & 6^2+1+800- 4^2\\ & \overset{E}{=} & 36 +1+800- 16\\ & \overset{A,S}{=} & 821 \end{array}$
Sarah's complete number is $1-713-555-1821$. Lucky Timothy.
• ### Find out how many eggs and how much flour Sally needs for her cookie recipe.
Hints
Evaluate Parentheses before Exponents.
When solving a problem, you can often simplify expressions by using PEMDAS.
Start with the Parentheses. Evaluate the Subtraction operators outside the parentheses in both expressions last.
You have to follow the rules of PEMDAS inside the parentheses, too.
Solution
What we have here is a really tasty recipe for cookies. But someone has substituted the amounts for eggs and flour with some longer mathematical expressions. We have to evaluate the expressions before we can go on baking. Let us take a look and see how many eggs we need:
$\begin{array}{rcl} (8-\frac{15}{5} \times 2)^3-\frac{(2+3)^2}{25} & \overset{D, A}{\longrightarrow} & (8-3 \times 2)^3-\frac{5^2}{25}\\ & \overset{M}{\longrightarrow} & (8-6)^3-\frac{5^2}{25}\\ & \overset{P}{\longrightarrow} & 2^3- \frac{5^2}{25}\\ & \overset{E}{\longrightarrow} & 8 - \frac{25}{25}\\ & \overset{D}{\longrightarrow} & 8 - 1\\ & \overset{S}{\longrightarrow} & 7 \end{array}$
We solve the parentheses first. Inside of the left parentheses, we have to simplify the fraction first. Then we multiply $3$ and $2$ and finally subtracted the two numbers. It's very important to follow the rules of PEMDAS inside parentheses, too.
After evaluating the parentheses, we should move on to the exponents. Now we can simplify the last fraction on the right side before subtracting in the end. That leaves us with $7$ eggs!
And how much flour do we need? Let's solve the last problem:
$\begin{array}{rcl} \frac{(6+2)^2}{4^2} \times 3 - \frac{(\frac42) ^3}{2^2} \times 3 & \overset{A,D}{\longrightarrow} & \frac{8^2}{4^2} \times 3 - \frac{2 ^3}{2^2} \times 3\\ & \overset{E}{\longrightarrow} & \frac{64}{16}\times 3 - \frac84 \times 3\\ & \overset{D}{\longrightarrow} & 4 \times 3 - 2 \times 3\\ & \overset{M}{\longrightarrow} & 12 - 6 \\ & \overset{S}{\longrightarrow} & 6 \end{array}$
For solving this expression, we solved the Parentheses first. Then we can evaluate the Exponents followed by Multiplication and Division. Finally, we subtracted from left to right. We found out that we need $6$ cups of flour.
Thanks to PEMDAS, we can now start baking!!!
• ### Identify the mnemonic used to remember PEMDAS.
Hints
Look at the initials of the words.
Which letters are in the acronym PEMDAS?
Solution
With PEMDAS you can simplify expressions: you simply have to follow the rules.
First evaluate Parentheses, then Exponents, followed by Multiplication and Division and finally you evaluate Addition and Subtraction.
Remember to always evaluate Multiplication and Division as well as Addition and Subtraction from left to right!
You can remember this order with a funny mnemonic:
Please Excuse My Dear Aunt Sally.
• ### Simplify the expressions by using the order of operations.
Hints
PEMDAS stands for:
• Parentheses
• Exponents
• Multiplication & Division
$\begin{array}{rcl} 75 - 2 \times \left( 3 + \frac{\left(3+24 \right)}{9} \right)^2 & \overset{P,P,A}{\longrightarrow} & 75 - 2 \times \left( 3 + \frac{27}{9} \right)^2\\ & \overset{P,D}{\longrightarrow} & 75 - 2 \times \left( 3+3 \right)^2\\ & \overset{P,A}{\longrightarrow} & 75 - 2 \times 6^2\\ & \overset{E}{\longrightarrow} & 75 - 2 \times 36\\ & \overset{M}{\longrightarrow} & 75 - 72\\ & \overset{S}{\longrightarrow} & 3 \end{array}$
|
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https://trac.fact-project.org/changeset/19293
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# Changeset 19293
Ignore:
Timestamp:
Oct 24, 2018, 8:59:24 PM (2 years ago)
Message:
kSolarStandardHorizon for convenience (no need to include libnova.h and no need to copy all these variables. A refernce is enough.
File:
1 edited
Unmodified
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https://forum.math.toronto.edu/index.php?PHPSESSID=mseudlilqgak7j1s97lg38os10&action=printpage;topic=194.0
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# Toronto Math Forum
## MAT244-2013S => MAT244 Math--Lectures => Ch 1--2 => Topic started by: Victor Ivrii on January 17, 2013, 02:18:45 PM
Title: Bonus problem for week 2
Post by: Victor Ivrii on January 17, 2013, 02:18:45 PM
Equation
$$y'=\frac{y-x-2}{y+x}$$
by a change of variables $x=t+a$, $y=z+b$reduce to homogeneous equation and solve it. Express $y$ as an implicit function of $x$:
$$F(x,y)=C.$$
Title: Re: Bonus problem for week 2
Post by: Changyu Li on January 18, 2013, 01:41:07 AM
$x = u+h \\ y = v+k\\$
at $(u,v) = 0\\$
$k - h - 2 = 0 \\ h + k = 0 \\ \Rightarrow h = -1,\;k = 1\\$
$x = u - 1 \\ dx = du\\ y = v + 1 \\ dy = dv \\$
$$\frac{dv}{du} = \frac{v-u}{u+v} \\$$
let $v = ut,\;\frac{dv}{du}=t+u \frac{dt}{du}$
$$t + u \frac{dt}{du}=\frac{ut-u}{u+ut} = \frac{t-1}{1+t}$$
simplify with magic
$$\frac{1}{u} du = \frac{1+t}{-1-t^2}dt \\ \ln \left| u \right| = -\frac{1}{2}\ln \left| t^2 +1 \right| -\arctan t + C \\ \ln \left| u \right| = -\frac{1}{2}\ln \left| \left( \frac{v}{u} \right) ^2 +1 \right| -\arctan \left( \frac{v}{u} \right) + C \\ \ln \left| x+1 \right| = -\frac{1}{2}\ln \left| \left( \frac{y-1}{x+1} \right) ^2 +1 \right| -\arctan \left( \frac{y-1}{x+1} \right) + C$$
Title: Re: Bonus problem for week 2
Post by: Victor Ivrii on January 18, 2013, 02:08:11 AM
Please change a name to one which allows to identify you.
Correct final steps as $\int \frac{1}{1+t^2}\,dt$ calculated incorrectly.
Also type \tan \ln to produce $\tan, \ln$ etc; $\arctan(z)$ is preferable to $\tan^{-1}(z)$ which could be confused with $1/\tan(z)$.
Note: the final expression could be simplified.
Title: Re: Bonus problem for week 2
Post by: Changyu Li on January 18, 2013, 02:28:56 AM
Title: Re: Bonus problem for week 2
Post by: Victor Ivrii on January 18, 2013, 02:38:46 AM
The final expression as I mentioned could be simplified
$$\frac{1}{2}\ln \bigl( (y-1)^2+(x+1)^2 \bigr) + \arctan \left( \frac{y-1}{x+1} \right) = C.$$
Title: Re: Bonus problem for week 2
Post by: Brian Bi on January 20, 2013, 08:59:46 PM
let $v = ut,\;\frac{dv}{du}=t+u \frac{dt}{du}$
What's the motivation for this? Inspired guess?
Title: Re: Bonus problem for week 2
Post by: Victor Ivrii on January 21, 2013, 12:49:00 AM
let $v = ut,\;\frac{dv}{du}=t+u \frac{dt}{du}$
What's the motivation for this? Inspired guess?
Standard method solving homogeneous equations i.e. of the form $y'=f(y/x)$.
Title: Re: Bonus problem for week 2
Post by: Brian Bi on January 21, 2013, 01:13:56 AM
I see. Is this covered in class or in the textbook? I can't find it in the textbook.
Title: Re: Bonus problem for week 2
Post by: Changyu Li on January 21, 2013, 01:50:39 AM
Problem 30 from chapter 2.2 in the tenth edition is a similar problem with a partial solution.
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https://www.wyzant.com/resources/answers/topics/system-of-equations
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435 Answered Questions for the topic System of Equations
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#### Write a system of equations for the situation. No need to solve!
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#### Solve equations X+2y=12 and 3x-3y=4 with subsitution and elimination.
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https://astronomy.stackexchange.com/questions/20840/what-leads-to-increase-in-opacity-in-kappa-mechanism
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# What leads to increase in opacity in kappa mechanism?
I understand that the kappa mechanism (that leads to star variability) causes an increase of opacity with increasing temperature in partial ionization zones. However, I'm not sure I understand what causes the increasing opacity with temperature.
Until recently, I thought that the increasing opacity was due to increasing Thompson opacity due to the increasing ionization fraction with temperature in partial ionization zones. However, some things I read suggested that that was not the cause. So I wanted to ask, what is the cause of increasing opacity with temperature in partial ionization zones?
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https://byjus.com/physics/displacement-periodic-function/
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# Displacement as a function of time and Periodic function
To understand this idea of displacement as a function of time, we will have to derive an expression for displacement, assume a body travelling at an initial velocity of $v_1$ at time $t_1$ and then the body accelerates at a constant acceleration of ‘$a$’ for some time and a final velocity of $v_2$ at time $t_2$, keeping these things in assumption let’s derive the following.
Let’s write displacement as,
$d$ = $V_{average}*\Delta t$
Where $\Delta t$ is the change in time, assuming that the object is under constant acceleration.
$d$ = $(\frac{V_1 + V_2}{2})* \Delta t$
Where $V_2$ and $V_1$ are final and initial velocities respectively, let’s rewrite final velocity in terms of initial velocity for the sake of simplicity.
$d$=$(\frac{V_1 + (V_1~+~a*\Delta t)}{2})* \Delta t$
Where $a$ is the constant acceleration the body is moving at, now if we rewrite the above as,
$d$ = $(\frac{2*V_1}{2} + \frac{a*\Delta t}{2})*\Delta t$
The above expression is one of the most fundamental expressions in kinematics, it is also sometimes given as
$d$ = $V_{i} t~+~\frac{1}{2}at^2$
Where $V_i$ is the initial velocity and $t$ is actually the change in time, all the quantities in this derivation like Velocity, displacement and acceleration are vector quantities.
If we have a look at our final expression, it is very clear that change in displacement depends upon time.
## Example of an oscillating pendulum
Now if we draw a displacement-time graph of this oscillating pendulum bob, we will get something like this,
The graph of the motion of the bob shows us how the displacement varies with respect to time, when bob reaches highest point, the potential energy is maximum and the kinetic energy is minimum as the velocity is equal to zero, we can easily deduce that the velocity is equal to zero, by looking at the slope of the displacement-time graph at specific times.
Slope A is positive in the graph stating that the velocity of the body is also positive, or in the forward direction.
Slope B is equal to zero meaning that the velocity of the body is zero, meaning there is no motion at this point.
Slope C is negative in the graph stating that the velocity of the body is also negative, or in the reverse direction.
The magnitude of velocity is always positive, it is the direction that decides if the velocity is positive or negative.
The displacement of the bob repeats after certain amount of time, it is a periodic function hence the displacement at any given time in the future can be predicted if we know the time and the time period of the pendulum, hence we can say that displacement is a function of time.
To learn concepts in a simplified way join us here at BYJU’S.com
#### Practise This Question
A transformer has 1500 turns in the primary coil and 1125 turns in the secondary coil. If the voltage in the primary coil is 200 V, then the voltage in the secondary coil is
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https://docs.datadrivendiscovery.org/devel/d3m.metrics.html
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# d3m.metrics module¶
class d3m.metrics.AccuracyMetric(all_labels=None)[source]
Bases: d3m.metrics._AllAsMultiLabelBase
Supports binary, multi-class, multi-label, and multi-task predictions.
score_one(truth_target_encoded, predictions_target_encoded, all_labels)[source]
Return type
float
class d3m.metrics.F1MacroMetric(all_labels=None)[source]
Bases: d3m.metrics._AllAsMultiLabelBase
Supports multi-class, multi-label, and multi-task predictions.
score_one(truth_target_encoded, predictions_target_encoded, all_labels)[source]
Return type
float
class d3m.metrics.F1Metric(pos_label)[source]
Bases: d3m.metrics._MultiTaskBase
score_one(truth_target, predictions_target)[source]
Return type
float
class d3m.metrics.F1MicroMetric(all_labels=None)[source]
Bases: d3m.metrics._AllAsMultiLabelBase
Supports multi-class, multi-label, and multi-task predictions.
score_one(truth_target_encoded, predictions_target_encoded, all_labels)[source]
Return type
float
class d3m.metrics.HammingLossMetric(all_labels=None)[source]
Bases: d3m.metrics._AllAsMultiLabelBase
Hamming loss gives the percentage of wrong labels to the total number of labels. Lower the hamming loss, better is the performance of the method used.
score_one(truth_target_encoded, predictions_target_encoded, all_labels)[source]
Return type
float
class d3m.metrics.HitsAtKMetric(k)[source]
Bases: d3m.metrics._RankMetricBase
The computes how many elements of a vector of ranks make it to the top ‘k’ positions. Consider the example:
learningData:
d3mIndex subject object relationship (target) 0 James John father 1 John Patricia sister 2 Robert Thomas brother … …
truth:
d3mIndex relationship 0 father 1 sister 2 brother
predictions:
d3mIndex relationships rank 0 brother 1 0 cousin 2 0 mother 3 0 father 4 * 0 grandfather 5 1 sister 1 * 1 mother 2 1 aunt 3 2 father 1 2 brother 2 * 2 sister 3 2 grandfather 4 2 aunt 5
Note that ranks (of truth relationships in the predictions) = [4,1,2] Hits@3 = 2/3 = 0.666666 Hits@1 = 1/3 = 0.3333333 Hits@5 = 3/3 = 1.0
score(truth, predictions)[source]
Return type
float
class d3m.metrics.JaccardSimilarityScoreMetric(pos_label)[source]
Bases: d3m.metrics._MultiTaskBase
score_one(truth_target, predictions_target)[source]
Return type
float
class d3m.metrics.MeanAbsoluteErrorMetric[source]
Supports univariate and multivariate.
score(truth, predictions)[source]
Return type
float
class d3m.metrics.MeanReciprocalRankMetric[source]
Bases: d3m.metrics._RankMetricBase
This computes the mean of the reciprocal of elements of a vector of rankings. This metric is used for linkPrediction problems. Consider the example:
learningData:
d3mIndex subject object relationship (target) 0 James John father 1 John Patricia sister 2 Robert Thomas brother … …
truth:
d3mIndex relationship 0 father 1 sister 2 brother
predictions:
d3mIndex relationships rank 0 brother 1 0 cousin 2 0 mother 3 0 father 4 * 0 grandfather 5 1 sister 1 * 1 mother 2 1 aunt 3 2 father 1 2 brother 2 * 2 sister 3 2 grandfather 4 2 aunt 5
Note that ranks (of truth relationships in the predictions) = [4,1,2] MRR = np.sum(1/ranks)/len(ranks) MRR = 0.58333
score(truth, predictions)[source]
Return type
float
class d3m.metrics.MeanSquareErrorMetric[source]
Supports univariate and multivariate.
score(truth, predictions)[source]
Return type
float
class d3m.metrics.Metric[source]
Bases: object
classmethod align(truth, predictions)[source]
Aligns columns and rows in predictions to match those in truth.
It requires that all index values in truth are present in predictions and only those. It requires that any column name in truth is also present in predictions. Any additional columns present in predictions are pushed to the right.
Parameters
• truth (~Truth) – Truth DataFrame.
• predictions (~Predictions) – Predictions DataFrame.
Returns
Return type
Predictions with aligned rows.
classmethod get_confidence_column(dataframe)[source]
Returns only confidence column present in dataframe.
Return type
DataFrame
classmethod get_index_column(dataframe)[source]
Returns only index column present in dataframe.
Return type
DataFrame
classmethod get_rank_column(dataframe)[source]
Returns only rank column present in dataframe.
Return type
DataFrame
classmethod get_target_columns(dataframe)[source]
Returns only target columns present in dataframe.
Return type
DataFrame
classmethod is_empty_value(v)[source]
Return type
bool
classmethod one_hot_encode_confidence(series, all_labels)[source]
Returns one-hot-encoded dataframe where the columns are the labels of the confidence column, which is provided as a series of tuples, where each tuple contains confidence for all labels of a given sample, ordered in order specified by labels.
Returned dataframe has instead of 0 or 1, a confidence value itself.
Return type
DataFrame
classmethod one_hot_encode_target(series, all_labels)[source]
Returns one-hot-encoded dataframe where the columns are the labels of the target column, which is provided as a series of tuples, where each tuple contains all labels of a given sample.
Return type
DataFrame
abstract score(truth, predictions)[source]
Return type
Any
classmethod vectorize_columns(dataframe)[source]
For every non-index column, convert all values in rows belonging to the same index to one row with value being a tuple of values. The order of values in a tuple follows the order of original rows. Missing/empty values are removed and not included in the tuple.
Return type
DataFrame
class d3m.metrics.NormalizeMutualInformationMetric[source]
score(truth, predictions)[source]
Return type
float
class d3m.metrics.ObjectDetectionAveragePrecisionMetric[source]
score(truth, predictions)[source]
Return type
float
class d3m.metrics.PrecisionAtTopKMetric(k)[source]
score(truth, predictions)[source]
Return type
float
class d3m.metrics.PrecisionMetric(pos_label)[source]
Bases: d3m.metrics._MultiTaskBase
score_one(truth_target, predictions_target)[source]
Return type
float
class d3m.metrics.RSquaredMetric[source]
Supports univariate and multivariate.
score(truth, predictions)[source]
Return type
float
class d3m.metrics.RecallMetric(pos_label)[source]
Bases: d3m.metrics._MultiTaskBase
score_one(truth_target, predictions_target)[source]
Return type
float
class d3m.metrics.RocAucMacroMetric(all_labels=None)[source]
Bases: d3m.metrics._RocAucBase
Supports multi-class and multi-label predictions.
score(truth, predictions)[source]
Return type
float
class d3m.metrics.RocAucMetric(all_labels=None)[source]
Bases: d3m.metrics._RocAucBase
Supports binary predictions.
score(truth, predictions)[source]
Return type
float
class d3m.metrics.RocAucMicroMetric(all_labels=None)[source]
Bases: d3m.metrics._RocAucBase
Supports multi-class and multi-label predictions.
score(truth, predictions)[source]
Return type
float
class d3m.metrics.RootMeanSquareErrorMetric[source]
Supports univariate and multivariate.
score(truth, predictions)[source]
Return type
float
|
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|
https://physics.stackexchange.com/questions/338789/how-many-compactifications-of-minkowski-space-are-possible
|
# How many compactifications of Minkowski space are possible?
Given an $n$-dimensional Minkowski space, how many spacetime manifolds can one obtain by some compactification of it?
In two dimensions, I can think of those, at least :
• The spacelike cylinder $\Bbb R_t \times S_x = \Bbb R^2 / \Bbb Z$
• The timelike cylinder $S_t \times \Bbb R_x = \Bbb R^2 / \Bbb Z$
• The torus $S_t \times S_x = \Bbb R^2 / \Bbb Z^2$
• The Klein bottle $\mathbb K = \Bbb R^2 / \sim$, $\sim$ the usual identification (I'm guessing it comes in both timelike and spacelike flavors)
• Misner space $\Bbb R^2 / B$, $B$ a Lorentz boost
• The timelike Moebius strip
• The spacelike Moebius strip
• The non-time orientable cylinder obtained by $(\Bbb R^2 / \Bbb Z) / (I \times T)$, $I$ some involution and $T$ time reversal
There are probably a bunch more, but those are the ones that pop to mind. The list seems fairly long, but I'm not really sure how to generalize it to any dimension.
I'm guessing that since they all can be expressed as a quotient, that is the thing to look into, the full list of discrete proper free groups that leave Minkowski space invariant, but there are of course infinitely many so. What classes can be found that will lead to distinct spacetimes?
There seems to be at least the translations along spacelike and timelike directions (and null, I suppose), the same but with change of orientation, and some involutions for the already compactified groups. Are those all the possible ones?
• I think you might want to be more precise/explicit in specifying when you consider compactifications as equivalent (Riemannian structure? smooth structure?) – Danu Jun 11 '17 at 19:26
• Being isometric, I suppose. Maybe up to finitely many continuous parameters (corresponding to the characteristic dimension of that compactification) – Slereah Jun 11 '17 at 19:30
|
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|
https://mathematica.stackexchange.com/questions/105046/timelineplot-handling-dates-prior-to-year-zero
|
# TimelinePlot - Handling dates prior to Year Zero
Interested in Using TimelinePlot to help me understand/remember important time periods in Earth prehistory and history.
Following an a simple example in the Documentation I create a TimelinePlot for Japanese history (data extracted from Wikipedia) using the List of Associations Application example.
TimelinePlot[<| "Yayoi" -> Interval[{"-300", "250"}],
"Kofun" -> Interval[{"250", "538"}],
"Asuka" -> Interval[{"538", "710"}],
"Nara" -> Interval[{"710", "794"}],
"Heian" -> Interval[{"794", "185"}],
"Kamakura" -> Interval[{"1185", "1333"}],
"Kenmu Restoration" -> Interval[{"1333", "1336"}],
"Muromachi" -> Interval[{"1336", "1573"}],
"Azuchi-Momoyama" -> Interval[{"1568", "1603"}],
"Edo" -> Interval[{"1603", "1868"}],
"Meiji" -> Interval[{"1868", "1912"}],
"Taisho" -> Interval[{"1912", "1926"}],
"Showa" -> Interval[{"1925", "1989"}],
"Heisei" -> Interval[{"1989", "2016"}]|>,
ImageSize -> {Automatic, 300}]
This works more or less as expected. However, it does not handle dates prior to Zero (BC) correctly. Note the Yayoi Period beginning in 300 BC and ending in 250 AD is improperly plotted. Similarly, if the Jomon period (14000 BC to 300 BC) is plotted it too gets confused.
Since I am especially interested in date intervals that start back well before historical times but at times may enter into the Common Era, I need to specify dates "BC" correctly. How can one plot intervals that might might cross the Zero boundary (BCE to CE date intervals) so that the plot reads properly? I notice that DateString[] can be modified using $DateStringFormat to handle "ADBC" or "CEBCE" date types. However, I can't seem to figure out how I should respecify the Date Interval[{}] to correctly handle such cases. The documentation is rather thin on this point. Obviously, setting the text number to a minus value within quotes doesn't work. Replacing the first association with "Yayoi" -> Interval[{Block[{$DateStringFormat = "ADBC"}, "300 BC"], "250"}]
doesn't either.
Anyone have any suggestions as to the correct way to do this?
DateObject seems to get the job done, e.g.:
"Yayoi" -> Interval[{DateObject[{-300}], "250"}]
It may not be able to help since it has been a while, but the problem was the string format of dates:
In[69]:= DateList["-300"]
Out[69]= {300, 1, 1, 0, 0, 0.}
In[70]:= DateList[{-300}]
Out[70]= {-300, 1, 1, 0, 0, 0.}
Besides Mr.Wizard♦'s suggestion, DateFunction can also be used.
TimelinePlot[data, ImageSize -> {Automatic, 300}, DateFunction -> ({ToExpression@#} &)]
Note that there is another anomaly in the plot; that is "Heian" is blocked by "Kofun", and that is because the dates in the interval for "Heian" is reversed. Fixing it will produce a correct TimelinePlot.
"Heian" -> Interval[{"794", "185"}],
• Nevertheless, it might help other people who come across this. Thanks for posting this! – J. M.'s torpor Aug 10 '16 at 22:01
|
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|
https://asmedigitalcollection.asme.org/FEDSM/proceedings-abstract/FEDSM2002/36150/445/298001
|
Numerical simulation of transient cavitating flow in a axisymmetric nozzle was conducted in order to investigate the detailed motion of cavitation bubble clouds which may be dominant to atomization of a liquid jet. Two-way coupled bubble tracking technique was assigned in the present study to predict the unsteady cloud cavitation phenomena. Large Eddy Simulation (LES) was used to predict turbulent flow. Calculated pressure distribution and injection pressure were compared with measured ones. Then, calculated motion of cavitation bubble clouds was carefully investigated to understand the cavitation phenomena in a nozzle. As a result, the following conclusions were obtained: (1) Calculated result of pressure distribution along the wall, the relation between injection pressure vs. flow rate, and bubble distribution agreed with existing experimental result. (2) Cavitation bubble clouds were periodically shed from the tail of vena contracta, which usually formed by the coalescence of a few small bubble clouds. (3) Collapse of cavitation bubbles due to the re-entrant jet was observed in the numerical simulation.
This content is only available via PDF.
|
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|
https://planetmath.org/SpecialElementsInARelationAlgebra
|
special elements in a relation algebra
Let $A$ be a relation algebra with operators $(\vee,\wedge,\ ;,^{\prime},^{-},0,1,i)$ of type $(2,2,2,1,1,0,0,0)$. Then $a\in A$ is called a
• function element if $e^{-}\ ;e\leq i$,
• injective element if it is a function element such that $e\ ;e^{-}\leq i$,
• surjective element if $e^{-}\ ;e=i$,
• reflexive element if $i\leq a$,
• symmetric element if $a^{-}\leq a$,
• transitive element if $a\ ;a\leq a$,
• subidentity if $a\leq i$,
• antisymmetric element if $a\wedge a^{-}$ is a subidentity,
• equivalence element if it is symmetric and transitive (not necessarily reflexive!),
• domain element if $a\ ;1=a$,
• range element if $1\ ;a=a$,
• ideal element if $1\ ;a\ ;1=a$,
• rectangle if $a=b\ ;1\ ;c$ for some $b,c\in A$, and
• square if it is a rectangle where $b=c$ (using the notations above).
These special elements are so named because they are the names of the corresponding binary relations on a set. The following table shows the correspondence.
element in relation algebra $A$ binary relation on set $S$
function element function (on $S$)
injective element injection
surjective element surjection
reflexive element reflexive relation
symmetric element symmetric relation
transitive element transitive relation
subidentity $I_{T}:=\{(x,x)\mid x\in T\}$ where $T\subseteq S$
antisymmetric element antisymmetric relation
equivalence element symmetric reflexive relation (not an equivalence relation!)
domain element $\operatorname{dom}(R)\times S$ where $R\subseteq S^{2}$
range element $S\times\operatorname{ran}(R)$ where $R\subseteq S^{2}$
ideal element
rectangle $U\times V\subseteq S^{2}$
square $U^{2}$, where $U\subseteq S$
${{{{}\end{center}\inner@par\thebibliography\bibitem{sg}S.R.Givant,\emph{The % Structure of Relation Algebras Generated by Relativizations},% AmericanMathematicalSociety(1994).\endthebibliography\begin{flushright}\begin{% tabular}[]{|ll|}\hline Title&special elements in a relation algebra\\ Canonical name&SpecialElementsInARelationAlgebra\\ Date of creation&2013-03-22 17:48:43\\ Last modified on&2013-03-22 17:48:43\\ Owner&CWoo (3771)\\ Last modified by&CWoo (3771)\\ Numerical id&9\\ Author&CWoo (3771)\\ Entry type&Definition\\ Classification&msc 03G15\\ Defines&function element\\ Defines&injective element\\ Defines&surjective element\\ Defines&reflexive element\\ Defines&symmetric element\\ Defines&transitive element\\ Defines&equivalence element\\ Defines&domain element\\ Defines&range element\\ Defines&ideal element\\ Defines&rectangle\\ Defines&square\\ Defines&antisymmetric element\\ Defines&subidentity\\ \hline}\end{tabular}}}\end{flushright}\end{document}$
|
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|
http://atmel-studio-doc.s3-website-us-east-1.amazonaws.com/webhelp/GUID-90493D45-DB42-4BB8-9627-BAA0225A71E3-en-US-1/GUID-61E99498-26BF-4513-9B15-7A30E03B1B4E.html
|
# strncpy.S
/* Copyright (c) 2002, 2007 Marek Michalkiewicz
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in
the documentation and/or other materials provided with the
distribution.
* Neither the name of the copyright holders nor the names of
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE. */
/* $Id$ */
/** \file */
/** \ingroup avr_string
\fn char *strncpy(char *dest, const char *src, size_t len)
\brief Copy a string.
The strncpy() function is similar to strcpy(), except that not more than n
bytes of src are copied. Thus, if there is no null byte among the first n
bytes of src, the result will not be null-terminated.
In the case where the length of src is less than that of n, the remainder
of dest will be padded with nulls.
\returns The strncpy() function returns a pointer to the destination
string dest. */
#if !defined(__DOXYGEN__)
#include "macros.inc"
#define dest_hi r25
#define dest_lo r24
#define src_hi r23
#define src_lo r22
#define len_hi r21
#define len_lo r20
ASSEMBLY_CLIB_SECTION
.global _U(strncpy)
.type _U(strncpy), @function
_U(strncpy):
X_movw ZL, src_lo
X_movw XL, dest_lo
.L_strncpy_loop:
subi len_lo, lo8(1)
sbci len_hi, hi8(1)
brcs .L_strncpy_done
ld __tmp_reg__, Z+
st X+, __tmp_reg__
tst __tmp_reg__
brne .L_strncpy_loop
; store null characters up to the end of dest
; as the glibc manual says:
; This behavior is rarely useful, but it is specified by the ISO C standard.
rjmp .L_strncpy_clr_start
.L_strncpy_clr_loop:
st X+, __zero_reg__
.L_strncpy_clr_start:
subi len_lo, lo8(1)
sbci len_hi, hi8(1)
brcc .L_strncpy_clr_loop
.L_strncpy_done:
; return dest (unchanged)
ret
.L_strncpy_end:
.size _U(strncpy), .L_strncpy_end - _U(strncpy)
#endif /* not __DOXYGEN__ */
|
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|
http://math.stackexchange.com/users/23645/john-hoffman?tab=activity
|
John Hoffman
Reputation
1,053
Top tag
Next privilege 2,000 Rep.
Nov 20 awarded Famous Question Nov 4 awarded Popular Question Jan 25 awarded Yearling Sep 29 awarded Favorite Question Sep 25 awarded Popular Question Aug 7 awarded Notable Question Jul 22 awarded Popular Question Jul 2 awarded Curious May 14 awarded Notable Question Mar 5 awarded Tumbleweed Feb 26 revised What's an efficient algorithm for walking to a minimum spanning tree? edited tags Feb 26 asked What's an efficient algorithm for walking to a minimum spanning tree? Feb 24 revised Can I maintain the set of vertices that connect to a starting vertex from a stream of edges in a directed graph? added 17 characters in body Feb 24 comment Can I maintain the set of vertices that connect to a starting vertex from a stream of edges in a directed graph? Yeah, the graph's directed … thanks for the inspiration though! Feb 24 asked Can I maintain the set of vertices that connect to a starting vertex from a stream of edges in a directed graph? Feb 23 comment How does substituting $\log{n}$ in help me solve this recurrence? Thanks, what do you mean by use the transformation that $S(n) = T(a^n)$? I know the master theorem, just not sure how it applies here. Feb 23 revised How does substituting $\log{n}$ in help me solve this recurrence? added 34 characters in body Feb 23 asked How does substituting $\log{n}$ in help me solve this recurrence? Jan 25 awarded Yearling Nov 7 awarded Good Question
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http://psychology.wikia.com/wiki/Spatial_frequency?direction=prev&oldid=105480
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# Spatial frequency
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In mathematics, physics, and engineering, spatial frequency is a characteristic of any structure that is periodic across position in space. The spatial frequency is a measure of how often the structure repeats per unit of distance. The SI unit of spatial frequency is cycles per meter. In image processing applications, the spatial frequency often is measured as lines per millimeter, which is 1000 times smaller than the SI unit.
In wave mechanics, the spatial frequency $\nu \$ is related to the wavelength $\lambda \$ by
$\nu \ = \ { 1 \over \lambda }$
Likewise, the wave number k is related to spatial frequency and wavelength by
$k \ = \ 2 \pi \nu \ = \ { 2 \pi \over \lambda }$
### Visual perception
In the study of visual perception, sinusoidal gratings are frequently used to probe the capabilities of the visual system. In these stimuli, spatial frequency is expressed as the number of cycles per degree of visual angle.
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https://geo.libretexts.org/Bookshelves/Geology/Book%3A_Gemology/16%3A_Gemstones/16.08%3A_Garnet/16.8.04%3A_Pyrope
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# 16.8.4: Pyrope
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Pyrope Garnet
Chemical composition Mg3Al2(SiO4)3agnesium aluminum silicate
Crystal system Cubic
Habit Dodecahedra
Cleavage None
Hardness 7.0-7.5
Dispersion Medium, 0.022
Optic nature Isotropic
Refractive index 1.730-1.760
Birefringence None
Specific gravity 3.65-3.80
Lustre Vitreous
Pyrope is a red, orange-red, brownish-red to pink species of the garnet group which forms isomorphous series with almandine, spessartite and grossular. Pyrope, like all other species of the garnet group, is seldom seen having its ideal chemical makeup.
## Diagnostics
### Spectroscope
Pyrope has a chromium spectrum that can be combined with the typical spectrum of almandine.
### Inclusions
• Rounded crystals of low relief
• Rutile needles
### Polariscope
Pyrope (in all its isomorphous series) may show anomalous birefringence.
### Refractometer
The refraction index of pyrope is 1.714 but, because it is never found pure, its index has a lower value of 1.730 and an upper value of 1.760.
Pyrope is singly refractive (isotropic).
### Specific gravity
Pure pyrope has a specific gravity of 3.58. Due to isomorphous replacement, this value is never measured. Instead, its value ranges from 3.65 to 3.80.
Pyrope sinks in all common heavy liquids.
## Varieties
### Rhodolite
Rhodolite is the purple variety of pyrope-almandine. The name and color come from the flower of the rhodondendron.
The jewelry trade sometimes describes every purple garnet as a rhodolite but it should be reserved only for those having an intermediate chemical composition between pyrope and almandine.
### Malaia
Malaia garnet (or malaya) is the red-orange variety of pyrope-spessartite discovered in the 1970's in Kenia as a by-product of rhodolite.
The name is derived from the Swahili word for prostitute (which freely translates to "outcast" or "out of the family") [see: Swahili - English Dictionary; Rouse, 1986].
• South-Africa
• USA
• Russia
## References
16.8.4: Pyrope is shared under a CC BY-NC-SA 2.5 license and was authored, remixed, and/or curated by gemology via source content that was edited to conform to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.
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https://www.projecteuclid.org/euclid.dmj/1510304420
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## Duke Mathematical Journal
### Spectral asymptotics for sub-Riemannian Laplacians, I: Quantum ergodicity and quantum limits in the 3-dimensional contact case
#### Abstract
This is the first paper of a series in which we plan to study spectral asymptotics for sub-Riemannian (sR) Laplacians and to extend results that are classical in the Riemannian case concerning Weyl measures, quantum limits, quantum ergodicity, quasimodes, and trace formulae. Even if hypoelliptic operators have been well studied from the point of view of PDEs, global geometrical and dynamical aspects have not been the subject of much attention. As we will see, already in the simplest case, the statements of the results in the sR setting are quite different from those in the Riemannian one.
Let us consider an sR metric on a closed $3$-dimensional manifold with an oriented contact distribution. There exists a privileged choice of the contact form, with an associated Reeb vector field and a canonical volume form that coincides with the Popp measure. We establish a quantum ergodicity (QE) theorem for the eigenfunctions of any associated sR Laplacian under the assumption that the Reeb flow is ergodic. The limit measure is given by the normalized Popp measure.
This is the first time that such a result is established for a hypoelliptic operator, whereas the usual Shnirelman theorem yields QE for the Laplace–Beltrami operator on a closed Riemannian manifold with ergodic geodesic flow.
To prove our theorem, we first establish a microlocal Weyl law, which allows us to identify the limit measure and to prove the microlocal concentration of the eigenfunctions on the characteristic manifold of the sR Laplacian. Then, we derive a Birkhoff normal form along this characteristic manifold, thus showing that, in some sense, all $3$-dimensional contact structures are microlocally equivalent. The quantum version of this normal form provides a useful microlocal factorization of the sR Laplacian. Using the normal form, the factorization, and the ergodicity assumption, we finally establish a variance estimate, from which QE follows.
We also obtain a second result, which is valid without any ergodicity assumption: every quantum limit (QL) can be decomposed in a sum of two mutually singular measures: the first measure is supported on the unit cotangent bundle and is invariant under the sR geodesic flow, and the second measure is supported on the characteristic manifold of the sR Laplacian and is invariant under the lift of the Reeb flow. Moreover, we prove that the first measure is zero for most QLs.
#### Article information
Source
Duke Math. J., Volume 167, Number 1 (2018), 109-174.
Dates
Revised: 15 May 2017
First available in Project Euclid: 10 November 2017
https://projecteuclid.org/euclid.dmj/1510304420
Digital Object Identifier
doi:10.1215/00127094-2017-0037
Mathematical Reviews number (MathSciNet)
MR3743700
Zentralblatt MATH identifier
06847243
#### Citation
Colin de Verdière, Yves; Hillairet, Luc; Trélat, Emmanuel. Spectral asymptotics for sub-Riemannian Laplacians, I: Quantum ergodicity and quantum limits in the 3-dimensional contact case. Duke Math. J. 167 (2018), no. 1, 109--174. doi:10.1215/00127094-2017-0037. https://projecteuclid.org/euclid.dmj/1510304420
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https://physics.stackexchange.com/questions/333856/what-is-the-physics-behind-the-energy-transferred-in-a-rotating-collision
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What is the physics behind the energy transferred in a 'rotating collision'?
In this video, we can see that rotating the paper somehow makes it less susceptible to being damaged. I can tell that the paper has some angular momentum. But how do we explain this phenomena in terms of energy transfer? It sort of remind me of how using simple equations, ( for momentum and energy) we can show that objects moving faster in a linear collision have less energy transferred to them. Is there an analogous description for 'rotating collisions'?
Moreover, would it be correct to say that the paper becomes harder when spinning very fast?
• I think it's less about "the paper takes less damage" and more like the "centrifugal" force makes the paper more rigid. A similar trick is to jam a straw into a potato: the straw buckles. But if you put your thumb over the end of the straw it is more successful because the trapped air in the straw adds rigidity. The limp paper was always sharp enough and strong enough to cut things, it just can't maintain its shape unless it is spinning. May 17 '17 at 20:27
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https://dsp.stackexchange.com/questions/44281/will-the-capacity-of-a-channel-becomes-unbounded-if-i-increase-its-signal-to-noi/44284
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# Will the capacity of a channel becomes unbounded if i increase its signal-to-noise ratio $S/N$ without limit?
According to the Shannon-Hartley theorem the capacity $C$ of a channel which has a signal-to-noise ratio of $S/N$ and a bandwidth $B$ can be calculated to be $C = B \log_2 \left( 1 + \frac{S}{N}\right)$. Heren if $B→\infty$, the capacity does not become infinite since, with an increase in bandwidth,the noise power also increases. If the noise power spectral density is $N_0/2$,then the total noise powr is $N=N_0B$,so the Shannon-Hartley law becomes \begin{align} C &= B \; \log_2 \left( 1 + \frac{S}{N_0B}\right) \\ &=\frac{S}{N_0}\left(\frac{N_oB}{S}\right)\log_2\left( 1 + \frac{S}{N_0B}\right) \\ &=\frac{S}{N_0}\log_2\left( 1 + \frac{S}{N_0B}\right)^{(\frac{N_0B}{S})}. \end{align} Now $$\lim_{x\to0}(1+x)^{1/x}=e$$ So now it becomes $$C_∞=\lim_{B\to\infty} C=\frac{S}{N_0}\log_2e=1.44\frac{S}{N_0}$$ so here channel capacity does not become infinite; that means, it's bounded.
But what happens if we increase the signal to noise ratio without bound? Will that give unbounded capacity? Is it possible?
After searching I got this but don't know how is this is possible; can some one justify this?
• Can you explain how do you obtain $C_{\infty}$? From your formula of $C$, it looks like, for fixed $S/N$, letting $B \rightarrow \infty$ implies $C \rightarrow \infty$. – MBaz Oct 10 '17 at 13:19
• @MBaz Actually i found the explantion for that in internet...i have edited my question...please check – Rohit Oct 10 '17 at 13:47
• In addition to the intuitive explanations below, you can see it as a simple consequence of the math: the logarithm is a monotonically increasing function, so for $W>0$, $W\log(x)\to\infty$ as $x\to\infty$. – MBaz Oct 10 '17 at 14:31
• An interesting mathematical result, but in the real world, general relativity (black holes) and QM will limit the S/N range. – hotpaw2 Oct 10 '17 at 15:26
• $$C = B \log_2 \left( 1 + \frac{S}{N}\right)$$ Herein if $B→\infty$, the capacity does not become infinite since, with an increase in bandwidth,the noise power also increases. ----- so what is preventing the signal power $S$ from increasing also as $B$ increases? in fact, in this Shannon Channel capacity formula, the noise power is defined to be fully within the bandwidth $B$. the more general channel capacity formula is: $$C = \int\limits_{0}^{B} \log_2 \left( 1 + \frac{S(f)}{N(f)}\right) \, df$$ so now $S(f)$ and $N(f)$ are the spectral densities of signal and noise at $f$. – robert bristow-johnson Oct 11 '17 at 3:42
There's a problem in the derivation for $C_\infty$.
Eventhough its mechanics is a quite simple limit process, the associated partially-true observation yields a misleading result; it assumes that when the bandwidth $B$ goes to infinity, so will be the total noise power $N$ (which is true), however the total signal power $S$ is assumed to be fixed (which is not true) as which may also go to infinity and hence the SNR $\frac{S}{N}$ would remain fixed! Rather it's assuming that signal energy $S$ is fixed and therefore SNR goes to zero as $B$ goes to infinity from which it would deduce that $$C_\infty = B_\infty \times \log(1 + SNR_\infty) = \infty \times \log(1) = \infty \times 0$$
Then he finds the limiting value as $$C_\infty = 1.44 \frac{S}{\eta}$$ where $S$ is the finite signal power that is transmitted through the infinite bandwidth channel and $\eta$ is the noise power spectral density.
You can easily see the fact that if you have infinite bandwidth $B$, then you could simultaneously transmit infinite different message signals $m_k(t)$ of each having a finite nonzero bitrate $R_k$ (for example by just using a simple FDM scheme) the total of which would add up to inifnite bits per second at once which make your information capacity to go infinity thereof.
Another consequence of SNR is the following observation: Given any analog channel with zero noise, it's information capacity is infinite. Proof: consider a system where you send an analog voltage level and the receiver converts it into a digital bitstream with N bits. If the channel has zero noise, then you can in principle send infinitely precise analog signal values. For example you can send the exact value of $\pi$ Volts over the channel. Since there is neither noise nor distortion in the channel (of smallest possible bandwidth) you would be transmitting infinite digits of the number $\pi$ to the receiver which requires infinite many bits to store. Therefore you send a single analog voltage evalue which is equivalent to infinite number of bits to represent digitally. When there's nonzero noise however, you can only transmit analog values up to noise floor precision which yields for example SNR based dynamic range limits of ADC systems.
• @Rohit what do you think about the answer ? dont you have any comments ? – Fat32 Oct 10 '17 at 17:15
• @Sorry sir...i had some urgent work that time,so i did't read your answer properly...i have still some doubt in the last paragraph of your answer but I will ask it lator.:-) – Rohit Oct 11 '17 at 9:08
By the sampling theorem, uniform samples taken at more than twice the bandwidth of a band-limited signal can be used to reconstruct the signal perfectly by sinc interpolation. For each different set of sample values there is a different band-limited function. In absence of noise, by increasing the bit depth of the samples one can store an unlimited amount of information per sample into the band-limited signal, and get it back simply by sampling and digitizing it again.
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http://drops.dagstuhl.de/opus/frontdoor.php?source_opus=2873
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When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.FSTTCS.2010.308
URN: urn:nbn:de:0030-drops-28739
URL: http://drops.dagstuhl.de/opus/volltexte/2010/2873/
Go to the corresponding LIPIcs Volume Portal
### Computing Rational Radical Sums in Uniform TC^0
pdf-format:
### Abstract
A fundamental problem in numerical computation and computational geometry is to determine the sign of arithmetic expressions in radicals. Here we consider the simpler problem of deciding whether $\sum_{i=1}^m C_i A_i^{X_i}$ is zero for given rational numbers $A_i$, $C_i$, $X_i$. It has been known for almost twenty years that this can be decided in polynomial time. In this paper we improve this result by showing membership in uniform TC0. This requires several significant departures from Blömer's polynomial-time algorithm as the latter crucially relies on primitives, such as gcd computation and binary search, that are not known to be in TC0.
### BibTeX - Entry
@InProceedings{hunter_et_al:LIPIcs:2010:2873,
author = {Paul Hunter and Patricia Bouyer and Nicolas Markey and Jo{\"e}l Ouaknine and James Worrell},
title = {{Computing Rational Radical Sums in Uniform TC^0}},
booktitle = {IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2010)},
pages = {308--316},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-939897-23-1},
ISSN = {1868-8969},
year = {2010},
volume = {8},
editor = {Kamal Lodaya and Meena Mahajan},
publisher = {Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
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http://en.wikipedia.org/wiki/Cotangent_bundle
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# Cotangent bundle
In mathematics, especially differential geometry, the cotangent bundle of a smooth manifold is the vector bundle of all the cotangent spaces at every point in the manifold. It may be described also as the dual bundle to the tangent bundle.
## The cotangent sheaf
Smooth sections of the cotangent bundle are differential one-forms.
### Definition of the cotangent sheaf
Let M be a smooth manifold and let M×M be the Cartesian product of M with itself. The diagonal mapping Δ sends a point p in M to the point (p,p) of M×M. The image of Δ is called the diagonal. Let $\mathcal{I}$ be the sheaf of germs of smooth functions on M×M which vanish on the diagonal. Then the quotient sheaf $\mathcal{I}/\mathcal{I}^2$ consists of equivalence classes of functions which vanish on the diagonal modulo higher order terms. The cotangent sheaf is the pullback of this sheaf to M:
$\Gamma T^*M=\Delta^*(\mathcal{I}/\mathcal{I}^2).$
By Taylor's theorem, this is a locally free sheaf of modules with respect to the sheaf of germs of smooth functions of M. Thus it defines a vector bundle on M: the cotangent bundle.
### Contravariance in manifolds
A smooth morphism $\phi\colon M\to N$ of manifolds, induces a pullback sheaf $\phi^*T^*N$ on M. There is an induced map of vector bundles $\phi^*(T^*N)\to T^*M$.
## The cotangent bundle as phase space
Since the cotangent bundle X=T*M is a vector bundle, it can be regarded as a manifold in its own right. Because of the manner in which the definition of T*M relates to the differential topology of the base space M, X possesses a canonical one-form θ (also tautological one-form or symplectic potential). The exterior derivative of θ is a symplectic 2-form, out of which a non-degenerate volume form can be built for X. For example, as a result X is always an orientable manifold (meaning that the tangent bundle of X is an orientable vector bundle). A special set of coordinates can be defined on the cotangent bundle; these are called the canonical coordinates. Because cotangent bundles can be thought of as symplectic manifolds, any real function on the cotangent bundle can be interpreted to be a Hamiltonian; thus the cotangent bundle can be understood to be a phase space on which Hamiltonian mechanics plays out.
### The tautological one-form
Main article: Tautological one-form
The cotangent bundle carries a tautological one-form θ also known as the Poincaré 1-form or Liouville 1-form. (The form is also known as the canonical one-form, although this can sometimes lead to confusion.) This means that if we regard T*M as a manifold in its own right, there is a canonical section of the vector bundle T*(T*M) over T*M.
This section can be constructed in several ways. The most elementary method is to use local coordinates. Suppose that xi are local coordinates on the base manifold M. In terms of these base coordinates, there are fibre coordinates pi: a one-form at a particular point of T*M has the form pidxi (Einstein summation convention implied). So the manifold T*M itself carries local coordinates (xi,pi) where the x are coordinates on the base and the p are coordinates in the fibre. The canonical one-form is given in these coordinates by
$\theta_{(x,p)}=\sum_{{\mathfrak i}=1}^n p_idx^i.$
Intrinsically, the value of the canonical one-form in each fixed point of T*M is given as a pullback. Specifically, suppose that π : T*MM is the projection of the bundle. Taking a point in Tx*M is the same as choosing of a point x in M and a one-form ω at x, and the tautological one-form θ assigns to the point (x, ω) the value
$\theta_{(x,\omega)}=\pi^*\omega.$
That is, for a vector v in the tangent bundle of the cotangent bundle, the application of the tautological one-form θ to v at (x, ω) is computed by projecting v into the tangent bundle at x using dπ : TT*MTM and applying ω to this projection. Note that the tautological one-form is not a pullback of a one-form on the base M.
### Symplectic form
The cotangent bundle has a canonical symplectic 2-form on it, as an exterior derivative of the canonical one-form, the symplectic potential. Proving that this form is, indeed, symplectic can be done by noting that being symplectic is a local property: since the cotangent bundle is locally trivial, this definition need only be checked on $\mathbb{R}^n \times \mathbb{R}^n$. But there the one form defined is the sum of $y_{i}dx_i$, and the differential is the canonical symplectic form, the sum of $dy_i{\and}dx_i$.
### Phase space
If the manifold $M$ represents the set of possible positions in a dynamical system, then the cotangent bundle $\!\,T^{*}\!M$ can be thought of as the set of possible positions and momenta. For example, this is a way to describe the phase space of a pendulum. The state of the pendulum is determined by its position (an angle) and its momentum (or equivalently, its velocity, since its mass is not changing). The entire state space looks like a cylinder. The cylinder is the cotangent bundle of the circle. The above symplectic construction, along with an appropriate energy function, gives a complete determination of the physics of system. See Hamiltonian mechanics for more information, and the article on geodesic flow for an explicit construction of the Hamiltonian equations of motion.
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https://stats.stackexchange.com/questions/314607/regression-on-predicting-time?noredirect=1
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# Regression on Predicting Time
If I have a dataset like this:
ID beg_lng beg_lat end_lng end_lat start_timestamp Time (sec)
0 -74.009087 40.713818 -74.004326 40.719986 1420950819 10
1 -73.971176 40.762428 -74.004181 40.742653 1420950819 1120
2 -73.994957 40.745079 -73.999939 40.73465 1421377541 321
Think of it a grocery shopping details of a delivery person. It has the starting lat/long where it starts and ending lat/long of destination. It also has the corresponding time it took in seconds (Time). start_timestamp is epoch in seconds of starting time.
Now if I want to build a regression model to predict the grocery delivery trip time, I tried first a basic crude method of linear regression with elastic net and put in all the above features (after standardizing them). I used the lat/long as given and didn't do much transformation.
However I get a very bad fit.
The mean train scores are [ 0.08447384 0.08447416 0.08447448 0.0844748 0.08447511 0.08448194
0.08448468 0.08448715 0.08448937 0.08449133 0.08453318 0.08451306
0.08446719 0.08439527 0.08429637 0.08253336 0.07888605 0.07359639
0.06619284 0.0578421 0.00454754 -0.00018343 -0.00018343 -0.00018343
-0.00018343]
The mean validation scores are [ 0.08389243 0.08389275 0.08389305 0.08389336 0.08389367 0.08390072
0.08390336 0.08390575 0.08390787 0.08390974 0.08395386 0.08393282
0.08388601 0.08381316 0.08371341 0.08197247 0.07835721 0.07306636
0.06565797 0.05737215 0.00448677 -0.00021397 -0.00021397 -0.00021397
-0.00021397]
The score on held out data is: 0.08395386395024673
Hyper-Parameters for Best Score : {'l1_ratio': 0.15, 'alpha': 0.01}
The R2 Score of sgd_regressor on test data is: 0.0864573982691922
The mse of sgd_regressor on test data is: 469651.012051
The mean absolute error of sgd_regressor on test data is: 422.247732739
Here is the Grid search code
def grid_search(self):
"""This function does Cross Validation using Grid Search
"""
from sklearn.model_selection import GridSearchCV
self.g_cv = GridSearchCV(estimator=self.estimator,param_grid=self.param_grid,cv=5)
self.g_cv.fit(self.train_X,self.train_Y)
And code to check the error:
def test_performance(self,name):
"""This method checks the performance of each algorithm on test data."""
from sklearn.metrics import mean_squared_error, mean_absolute_error
#
print("The R2 Score of "+ name + " on test data is: {}\n".format(self.g_cv.best_estimator_.score(self.test_X,self.test_Y)))
print ("The mse of "+ name + " on test data is:",\
mean_squared_error(test_Y, self.g_cv.best_estimator_.predict(self.test_X)))
print ("The mean absolute error of "+ name + " on test data is:",\
mean_absolute_error(test_Y, self.g_cv.best_estimator_.predict(self.test_X)))
Why am I getting such a bad R2 and errors? Any idea where I can be going wrong?
This is probably a case where a linear (or other) regression won't be very helpful. People will only ever go shopping at stores.
If midway between store A (where your user usually spends two minutes to buy a cup of coffee) and store B (where your user usually spends two hours to buy clothes), there is only a stretch of highway, it makes little sense to predict that he will shop there for about one hour.
Instead, it's probably better to use $k$-nearest neighbors, or a variant that only searches within a given maximum geographical radius. Which is pretty much a proxy for "identify the last $k$ visits to this store, then predict the average time spent there". Note that if you include the starting time stamp, you automatically make sure that only the last visits count (you may need to play around with the weights on the geographical vs. the time dimension here).
If there are less than $k$ previous visits, best to use the average of those visits we do have, not include a neighboring coffee shop or supermarket, which may not be comparable (that's where the "maximum geographical radius" comes in).
• This is a problem of a delivery guy's time of trip. If the delivery guy starts from start_lat/long and ends at end_lat/long then duration is the trip time we need to predict. I am not sure if lat/long can be tranformed to a better feature here? And how does Knn will be that much helpful? – Baktaawar Nov 20 '17 at 9:47
This response is really a comment but it quickly became too long for that format.
The discussion with @stephenkolassa makes the OPs query sound more like a bad variant of the classic TSP (Traveling Salesman Problem) which, with more than a few nodes, quickly becomes an Np-hard problem in terms of computational complexity. Nearest neighbor algorithms are commonly used in TSP solutions. So, +1 to Stephen for this suggestion.
I do have some points of difference. First of all, my view is that treating lat/long as continuous features is a mistake. To me, it would make more sense to discretize them in two possible ways (at least): first, treat lat/long in terms of 'distance traveled' or, second, by assigning them to a zip code. Both approaches would require digging up one of the widely available lat/long distance calculators (e.g., here ... http://www.nhc.noaa.gov/gccalc.shtml). This NOAA function can also be treated as a formula and coded up in your software for the large number of computations required.
Assignment of lat/long to a zip code is a little trickier insofar as it requires using the same distance or comparison function to find the zip code closest to each lat/long (starting and ending). In this case, the two lat/longs would be evaluated separately against the zip code lat/longs at their 'centroid.' Publicly available, accessible and free databases are out there that have zip code centroid lat/longs extracted from US census data (e.g., here ... https://stackoverflow.com/questions/19819418/up-to-date-zip-code-database). In addition, many of them have geodemographic enhancements such as median hhold income, population size, ethnicity, etc., which can also be leveraged for descriptive purposes. The caveat to this second approach is that zip code is a massively categorical feature, even if only using the approximately 36,000 residential zip codes. Treating a cross-product matrix of this size in a classic, closed form, ANOVA-type model would be prohibitive. Few machines on the planet would have sufficient RAM to decompose such a matrix. A hierachical bayesian workaround to this challenge is proposed in this paper by Steenburgh and Ainslie Massively Categorical Variables: Revealing the Information in Zip Codes (here ... http://bear.warrington.ufl.edu/centers/MKS/abstracts/vol22/no1/aab6f24ee7_abstract.pdf). A frequentist approach would be to leverage one of the many variants of divide and conquer algorithms out there which would reduce the problem to a more manageable size.
The first, discretizing solution is probably the way to go.
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http://aas.org/archives/BAAS/v37n4/aas207/502.htm
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AAS 207th Meeting, 8-12 January 2006
Session 63 From Here to Eternity: The Spitzer Legacy Programs
Poster, Tuesday, 9:20am-6:30pm, January 10, 2006, Exhibit Hall
## [63.14] The Spatially-Resolved Star Formation Law in M51
R.C. Kennicutt (IoA Cambridge), D. Calzetti (STScI), F. Walter (MPIA), M.K. Prescott (U. Arizona), SINGS Team
Most of our current knowledge of the star formation rate (SFR) vs gas density law in galaxies is based on spatially integrated measurements of disks, and thus averaged on scales of order 1 - 50 kpc. Thanks to a new generation of high-resolution multi-wavelength surveys of galaxies, it is now possible to probe the detailed behavior of the star formation law as a function of position within galaxies, with spatial resolutions of order 100 - 1000 pc. Such a program is a core component of the Spitzer Infrared Nearby Galaxies Survey (SINGS).
We present results from a study of the spatially-resolved star formation law in the nearby Sc galaxy M51a (NGC~5194). We have combined archival P\alpha maps of the center of the galaxy from HST, groundbased H\alpha images, and a 24~\mum infrared imaging from the SINGS project to map the extinction-corrected SFR in the disk. We have also used maps from The HI Nearby Galaxies Survey (THINGS) and CO maps from the BIMA SONG survey and other published surveys to map the corresponding distributions of atomic and molecular gas. We have correlated the SFRs and gas densities on scales of 7 - 45 arcsec (~300 - 1850 pc), and find that over all of these scales the relation is well represented by a Schmidt-type power law, with a slope (N ~ 1.5) similar to that found in integrated measurements of galaxies. We also present a new method for deriving extinction-corrected SFRs of HII regions and galaxies from the combination of 24~\mum and H\alpha measurements.
Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.
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https://brilliant.org/problems/tasty-trigo-3/
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Geometry Level 4
$\large\dfrac{a^2 + b^2 +c^2}{d^2}$
If $$a$$, $$b$$, $$c$$ and $$d$$ are side lengths of a quadrilateral, then what is the infimum value of the expression above?
×
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http://mathhelpforum.com/calculus/15921-cauchys-theorem-print.html
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# Cauchys Theorem
• June 13th 2007, 04:45 AM
moolimanj
Cauchys Theorem
Hi Any help with this question would be greatly appreciated - I just cant get my head around the squared term in the denominator:
(a) Evaluate the integral:
Int (e^zpi)/((z+i)(z-3i)^2) when
(i) C= {z:|z|=2}
(ii) C = {z:|z-1|=1}
(iii) C = {z:|z-2i|=2}
(b) Use liouvilles theorem to show that there is at least one value z subset C for which |sinz|>2007
(c) Show that if f is an entire function that satisfies |2007i+f(z)|>2007 then f is constant
(d) Deduce from the result in (b) that if f is an entire function that satisfies Im(f(z))>0 for all z subset c, then f is constant
Many thanks
• June 13th 2007, 06:44 AM
ThePerfectHacker
Quote:
Originally Posted by moolimanj
(b) Use liouvilles theorem to show that there is at least one value z subset C for which |sinz|>2007
Assume not! Then $|\sin z| \leq 2007$ for all $z\in \mathbb{C}$. Now since $f(z) = \sin z$ is an entire function it must mean that by Liouville's theorem that $\sin z = K$ for some complex number $K$, which is not true, i.e. $\sin \pi = 0 \mbox{ and }\sin \frac{
\pi}{2} = 1$
. Thus by contradiction $|\sin z| > 2007$ for some $z\in \mathbb{C}$.
Quote:
(c) Show that if f is an entire function that satisfies |2007i+f(z)|>2007 then f is constant
Hint: $||f(z)|-|2007i|| \leq |f(z) - 2007i| \leq |f(z)|+|2007i|$
$|2007i + f(z)| > 2007$
• June 13th 2007, 08:54 AM
ThePerfectHacker
1 Attachment(s)
Quote:
Originally Posted by moolimanj
(a) Evaluate the integral:
Int (e^zpi)/((z+i)(z-3i)^2) when
This is done by Cauchy's Integral Formula:
First we write,
$\oint_C \frac{e^{\pi z}}{(z+i)(z-3i)^2} dz = \oint_C e^{\pi z}\cdot \left( \frac{-1/16}{z+i} + \frac{1/16}{z-3i} + \frac{1/(4i)}{(z-3i)^2} \right) dz$
That was partial fractions.
Now, seperate the contour integrals over "Western Europe":
$\boxed{-\frac{1}{16}\oint_C \frac{e^{\pi z}}{z+i} dz + \frac{1}{16}\oint_C \frac{e^{\pi z}}{z-3i} dz + \frac{1}{4i} \oint_C \frac{e^{\pi z}}{(z-3i)^2} dz}$
Let me state the two theorems we need to know:
Theorem 1: Let $\gamma$ be a contour and let $f(z)$ be holomorphic in an open set containing the contour and its interior. Then for any point $a$ inside $\gamma$ we have:
$f(a) = \frac{1}{2\pi i} \oint_{\gamma} \frac{f(z)}{z-a} dz$
Theorem 2: Let $\gamma$ be a contour and let $f(z)$ be holomorphic in an open set containing the contour and its interior. Then for any point $a$ inside $\gamma$ we have:
$f'(a) = \frac{1}{2\pi i} \oint_{\gamma} \frac{f(z)}{(z-a)^2} dz$
Now we know enought to do this problem.
Quote:
(i) C= {z:|z|=2}
I will do this one and leave (ii) and (iii) for you to think about. Look below. The circle is shown and the red points are the singularities.
We have three contour integral we need to evaluate.
The second and third one are simple.
It is zero because "all poles are in Eastern Europe".
By that I mean that the function we are integrating are holomorphic in that circle. And Cauchy's Theorem (not the integral formula, the one with the contours) tells us that the integrals are zero.
So the problem reduces to find,
$-\frac{1}{16}\oint_C \frac{e^{\pi z}}{z-3i} dz$
The function here is clearly $f(z) = e^{\pi z}$ and it indeed satisfies Theorem 1.
So the Contour Integral is equal to:
$- \frac{1}{16} \cdot 2\pi i \cdot f(3i) = -\frac{\pi i e^{3\pi i}}{8} = - \frac{\pi i \cos 3\pi - \pi \sin 3\pi }{8} = \frac{\pi i}{8}$
• June 15th 2007, 04:42 AM
moolimanj
Cauchys
Thanks for you help on this perfecthacker
However, I cant figure out how to do part (a)(ii) and (iii).
if C={z:|z-1|=1 then 3i is again outside the circle. Does this mean that the answer is the same? -i in this instance is on the circle. I'm confused - if its on the circle, should the answer be 0, or would the answer be the same as part (i)?
Also for part (iii) if C={z:|z-2i|=2} then -i is excluded but 3i in included in the contour. So how can the answer be 0 by Cauchys theorem when at least one is contained within the circle. Please help
• June 15th 2007, 05:28 AM
ThePerfectHacker
1 Attachment(s)
Problem (ii): The contour integral is still the same:
$
\boxed{-\frac{1}{16}\oint_C \frac{e^{\pi z}}{z+i} dz + \frac{1}{16}\oint_C \frac{e^{\pi z}}{z-3i} dz + \frac{1}{4i} \oint_C \frac{e^{\pi z}}{(z-3i)^2} dz}
$
If it is on the circle, the contour integral is zero. But you made a mistake it is not on the circle. Both points are clearly outside the circle and hence by Cauchy's theorem its integral is zero.
EDIT: My picture is wrong. You were right, $i$ is on the circle. But anyways still the integral is zero.
• June 15th 2007, 05:39 AM
ThePerfectHacker
1 Attachment(s)
Problem (iii): Look at the picture below. As you say $3i$ is inside the contour and $-i$ is outside. That means the first integral in:
$
\boxed{-\frac{1}{16}\oint_C \frac{e^{\pi z}}{z+i} dz + \frac{1}{16}\oint_C \frac{e^{\pi z}}{z-3i} dz + \frac{1}{4i} \oint_C \frac{e^{\pi z}}{(z-3i)^2} dz}
$
Is zero by Cauchy's theorem.
However, the second and third one are not necessarily zero.
If you look at Theorem 1 and Theorem 2 that I posted. You will note that the function that we need here is $f(z)=e^{\pi z}$ to determine the value of each integral.
The first integral has $z-3i$ in the denominator so:
$\frac{1}{2\pi i}\oint_C \frac{e^{\pi z}}{z-3i} dz = f(3i) = e^{3\pi i} = \cos 3\pi + i \sin 3\pi = -1$.
To do the second integral we need the derivative: $f'(z) = \pi e^{\pi z}$ because it has $(z-3i)^2$ in the denominator. Thus:
$\frac{1}{2\pi i} \oint_C \frac{e^{\pi z}}{(z-3i)^2} dz = f'(3i) = \pi e^{3\pi i} = \pi \cos 3\pi + \pi i \sin 3\pi = - \pi$
Now you just have to add and simplify to get the answer which is trivial.
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# 1 Marie Duží vyučující: Marek Menšík Logika: systémový rámec rozvoje oboru v ČR a koncepce logických propedeutik pro mezioborová studia.
## Presentation on theme: "1 Marie Duží vyučující: Marek Menšík Logika: systémový rámec rozvoje oboru v ČR a koncepce logických propedeutik pro mezioborová studia."— Presentation transcript:
1 Marie Duží vyučující: Marek Menšík [email protected] Logika: systémový rámec rozvoje oboru v ČR a koncepce logických propedeutik pro mezioborová studia (reg. č. CZ.1.07/2.2.00/28.0216, OPVK)
Formal systems, Proof calculi A proof calculus (of a theory) is given by: 1. a language 2. a set of axioms 3. a set of deduction rules ad 1. The definition of a language of the system consists of: an alphabet (a non-empty set of symbols), and a grammar (defines in an inductive way a set of well- formed formulas - WFF) 2
Proof calculi: Example of a language: FOPL Alphabet: 1. logical symbols: (countable set of) individual variables x, y, z, … connectives , , , , quantifiers , 2. special symbols (of arity n) predicate symbols P n, Q n, R n, … functional symbols f n, g n, h n, … constants a, b, c, – functional symbols of arity 0 3. auxiliary symbols (, ), [, ], … Grammar: 1. terms each constant and each variable is an atomic term if t 1, …, t n are terms, f n a functional symbol, then f n (t 1, …, t n ) is a (functional) term 2. atomic formulas if t 1, …, t n are terms, P n predicate symbol, then P n (t 1, …, t n ) is an atomic (well-formed) formula 3. composed formulas Let A, B be well-formed formulas. Then A, (A B), (A B), (A B), (A B), are well-formed formulas. Let A be a well-formed formula, x a variable. Then xA, xA are well-formed formulas. 4. Nothing is a WFF unless it so follows from 1.-3. 3
Proof calculi Ad 2. The set of axioms is a chosen subset of the set of WFF. The axioms are considered to be basic (logically true) formulas that are not being proved. Example: {p p, p p}. Ad 3. The deduction rules are of a form: A 1,…,A m |– B 1,…,B m Enable us to prove theorems (provable formulas) of the calculus. We say that each B i is derived (inferred) from the set of assumptions A 1,…,A m. Examples: p q, p |– q(modus ponens) p q, q |– p(modus tollendo tollens) p q |– p, q(conjunction elimination) 4
A proof of a formula A (from logical axioms of the given calculus) is a sequence of formulas (proof steps) B 1,…, B n such that: A = B n (the proved formula A is the last step) each B i (i = 1,…,n) is either an axiom or B i is derived from the previous B j (j=1,…,i-1) using a deduction rule of the calculus. A formula A is provable by the calculus, denoted |– A, if there is a proof of A in the calculus. Provable formulas are theorems (of the calculus). 5 Proof calculi
A Proof from Assumptions A (direct) proof of a formula A from assumptions A 1,…,A m is a sequence of formulas (proof steps) B 1,…,B n such that: A = B n (the proved formula A is the last step) each B i (i=1,…,n) is either an axiom, or an assumption A k (1 k m), or B i is derived from the previous B j (j=1,…,i-1) using a rule of the calculus. A formula A is is provable from A 1, …, A m, denoted A 1,…,A m |– A, if there is a proof of A from A 1,…,A m. 6
An indirect proof of a formula A from assumptions A 1,…,A m is a sequence of formulas (proof steps) B 1,…,B n such that: each B i (i=1,…,n) is either an axiom, or an assumption A k (1 k m), or an assumption A of the indirect proof (formula A that is to be proved is negated) B i is derived from the previous B j (j=1,…,i-1) using a rule of the calculus. Some B k contradicts to B l, i.e., B k = B l (k {1,...,n}, l {1,...,n}) 7 A Proof from Assumptions
A sound calculus (sémanticky korektní): if | A (provable) then |= A (logically true) 8
A Complete Calculus: if |= A then | A Each logically valid formula is provable in the calculus. The set of theorems = the set of logically valid formulas (the red sector of the previous slide is empty). Sound and complete calculus: |= A iff | A Provability and logical validity coincide in FOPL (1 st -order predicate logic) There are sound and complete calculi for the FOPL, e.g.: Hilbert-like calculi, Gentzen calculi, natural deduction, resolution method, … 9
Semantics A semantically correct (sound) logical calculus serves for proving logically valid formulas (tautologies). In this case the axioms have to be logically valid formulas (true under all interpretations), and the deduction rules make it possible to prove logically valid formulas. For this reason the rules are either truth-preserving in general or preserving truth in an interpretation, i.e., A 1,…,A m |– B 1,…,B m can be read as follows: if all the formulas A 1,…,A m are logically valid formulas, then B 1,…,B m are logically valid formulas. 10
The Theorem of Deduction In a sound proof calculus the following Theorem of Deduction should be valid: Theorem of deduction. A formula is provable from assumptions A 1,…,A m, iff the formula A m is provable from A 1,…,A m-1. In symbols: A 1,…,A m |– iff A 1,…,A m-1 |– (A m ). In a sound calculus meeting the Deduction Theorem the following implication holds: If A 1,…,A m |– then A 1,…,A m |= . If the calculus is sound and complete, then provability coincides with logical entailment: A 1,…,A m |– iff A 1,…,A m |= . 11
The Theorem of Deduction If the calculus is sound and complete, then provability coincides with logical entailment: A 1,…,A m |– iff A 1,…,A m |= . Proof. If the Theorem of Deduction holds, then A 1,…,A m |– iff |– (A 1 (A 2 …(A m )…)). |– (A 1 (A 2 …(A m )…)) iff |– (A 1 … A m ) . If the calculus is sound and complete, then |– (A 1 … A m ) iff |= (A 1 … A m ) . |= (A 1 … A m ) iff A 1,…,A m |= . The first equivalence is obtained by applying the Deduction Theorem m-times, the second is valid due to the soundness and completeness, the third one is the semantic equivalence. 12
Properties of a calculus: axioms The set of axioms of a calculus is non-empty and decidable in the set of WFFs (otherwise the calculus would not be reasonable, for we couldn’t perform proofs if we did not know which formulas are axioms). It means that there is an algorithm that for any WFF given as its input answers in a finite number of steps an output Yes or NO on the question whether is an axiom or not. A finite set is trivially decidable. The set of axioms can be infinite. In such a case we define the set either by an algorithm of creating axioms or by a finite set of axiom schemata. The set of axioms should be minimal, i.e., each axiom is independent of the other axioms (not provable from them). 13
Properties of a calculus: deduction rules, consistency The set of deduction rules enables us to perform proofs mechanically, considering just the symbols, abstracting of their semantics. Proving in a calculus is a syntactic method. A natural demand is a syntactic consistency of the calculus. A calculus is consistent iff there is a WFF such that is not provable (in an inconsistent calculus everything is provable). This definition is equivalent to the following one: a calculus is consistent iff a formula of the form A A, or (A A), is not provable. A calculus is syntactically consistent iff it is sound (semantically consistent). 14
Properties of a calculus: (un)decidability There is another desirable property of calculi. To illustrate it, let’s raise a question: having a formula , does the calculus decide ? In other words, is there an algorithm that would answer in a finite number of steps Yes or No, having as input and answering the question whether is logically valid or no? If there is such an algorithm, then the calculus is decidable. If the calculus is complete, then it proves all the logically valid formulas, and the proofs can be described in an algorithmic way. However, in case the input formula is not logically valid, the algorithm does not have to answer (in a finite number of steps). Indeed, there is no decidable 1st order predicate logic calculus, i.e., the problem of logical validity is not decidable in the FOPL. (the consequence of Gödel Incompleteness Theorems) 15
Provable = logically true? Provable from … = logically entailed by …? The relation of provability (A 1,...,A n |– A) and the relation of logical entailment (A 1,...,A n |= A) are distinct relations. Similarly, the set of theorems |– A (of a calculus) is generally not identical to the set of logically valid formulas |= A. The former is syntactic and defined within a calculus, the latter is independent of a calculus, it is semantic. In a sound calculus the set of theorems is a subset of the set of logically valid formulas. In a sound and complete calculus the set of theorems is identical with the set of formulas. 16
„pre-Hilbert“ formalists „Mathematics is a game with symbols“ A simple system S: Constants: , Predicates: Axioms of S: (1) x ( x x) (2) x x (3) Inference rules: MP (modus ponens), E (general quantifier elimination), I (existential quantifier insertion) Theorem: Proof: (axiom 3) x x(I ) (axiom 2 and MP) (axiom 1 and E ) (MP) It is impossible to develop mathematics in such a purely formalist way. Instead: use only finitist methods (Gödel: impossible as well) 17
Historical background The reason why proof calculi have been developed can be traced back to the end of 19th century. At that time formalization methods had been developed and various paradoxes arose. All those paradoxes arose from the assumption on the existence of actual infinities. To avoid paradoxes, David Hilbert (a significant German mathematician) proclaimed the program of formalisation of mathematics. The idea was simple: to avoid paradoxes we will use only finitist methods: First: start with a decidable set of certainly (logically) true formulas, use truth-preserving rules of deduction, and infer all the logical truths. Second, begin with some sentences true in an area of interest (interpretation), use truth-preserving rules of deduction, and infer all the truths of this area. In particular, he intended to axiomatise in this way mathematics, in order to avoid paradoxes. 18
Historical background Hilbert supposed that these goals can be met. Kurt Gödel (the greatest logician of the 20th century) proved the completeness of the 1st order predicate calculus, which was expected. He even proved the strong completeness: if SA |= T then SA |– T (SA – a set of assumptions). But Hilbert wanted more: he supposed that all the truths of mathematics can be proved in this mechanic finite way. That is, that a theory of arithmetic (e.g. Peano) is complete in the following sense: each formula is in the theory decidable, i.e., the theory proves either the formula or its negation, which means that all the formulas true in the intended interpretation over the set of natural numbers are provable in the theory: Gödel’s theorems on incompleteness give a surprising result: there are true but not provable sentences of natural numbers arithmetic. Hence Hilbert program is not fully realisable. 19
Natural Deduction Calculus Axioms:A A, A A Deduction Rules: conjunction:A, B |– A B (IC) A B |– A, B (EC) disjunction:A |– A B or B |– A B(ID) A B, A |– B or A B, B |– A(ED) Implication:B |– A B(II) A B, A |– B (EI, modus ponens MP) equivalence:A B, B A |– A B(IE) A B |– A B, B A(EE) 20
Natural Deduction Calculus Deduction rules for quantifiers General quantifier: A x |– xA x I The rule can be used only if formula A x is not derived from any assumption that would contain variable x as free. xA x |– A x/t E Formula A x/t is a result of correctly substituting the term t for the variable x (no collision of variables). Existential quantifierA x/t |– xA x I xA x |– A x/c E where c is a constant not used in the language as yet. If the rule is used for distinct formulas, then a different constant has to be used. A more general form of the rule is: y 1... y n x A x, y 1,...,y n |– y 1... y n A x / f(y 1,...,y n ), y 1,...,y n General E 21
Natural Deduction (notes) 1. In the natural deduction calculus an indirect proof is often used. 2. Existential quantifier elimination has to be done in accordance with the rules of Skolemisation in the general resolution method. 3. Rules derivable from the above: A x B |– xA x B, x is not free in B A B x | – A xB x , x is not free in A A x B |– xA x B, x is not free in B A B x |– A xB x A xB x |– A B x xA x B |– A x B 22
Natural Deduction Another useful rules and theorems of propositional logic (try to prove them): Introduction of negation:A |– AIN Elimination of negation: A |– AEN Negation of disjunction: A B |– A B ND Negation of conjunction: A B |– A BNK Negation of implication: A B |– A BNI Tranzitivity of implication:A B, B C |– A CTI Transpozition:A B |– B ATR Modus tollens:A B, B |– AMT 23
Natural Deduction: Examples Theorem 1: A B, B |– A Modus Tollens Proof: 1. A Bassumption 2. Bassumption 3. Aassumption of the indirect proof 4. BMP: 1, 3contradicts to 2., hence 5. AQ.E.D 24
Natural Deduction: Examples Theorem 2: C D |– C D Proof: 1. C Dassumption 2. ( C D)assumption of indirect proof 3. ( C D) (C D)de Morgan (see the next example) 4. C DMP 2,3 5. CEC 4 6. D EC 4 7. DMP 1, 5 contradicts to 6, hence 8. C D (assumption of indirect proof is not true) Q.E.D. 25
Proof of an implicative formula If a formula F is of an implicative form: A 1 {A 2 [A 3 … (A n B) …]} (*) then according to the Theorem of Deduction the formula F can be proved in such a way that the formula B is proved from the assumptions A 1, A 2, A 3, …, A n. 26
The technique of branch proof from hypotheses Let the proof sequence contain a disjunction: D 1 D 2 … D k We introduce hypotheses D i (1 ≤ i ≤ k). If a formula F can be proved from each of the hypotheses D i, then F is proved. Proof (of the validity of branch proof): a) Theorem 4: [(p r) (q r)] [(p q) r] b) The rule II (implication introduction): B |– A B 27
The technique of branch proof from hypotheses Theorem 4: [(p r) (q r)] [(p q) r] 1.[(p r) (q r)]assumption 2.(p r) EK: 1 3.(q r)EK: 1 4.p qassumption 5. (p r) ( p r)Theorem 2 6. p rMP: 2.5. 7. rassumption of the indirect proof 8. pED: 6.7. 9.qED: 4.8. 10.rMP: 3.9. – contra 7., hence 11.rQ.E.D 28
The technique of branch proof from hypotheses Theorem 3: ( A B) (A B)de Morgan law Proof: 1.( A B) assumption 2.A Bassumption of the indirect proof 3. AEC 1. 4. BEC 1. 5.1.Ahypothesis: contradicts to 3 5.2.Bhypothesis: contradicts to 4. 5.A (A B)II 6. B (A B)II 7.[A (A B)] [B (A B)] IC 5,6 8. (A B) (A B) Theorem 4 9. (A B)MP 2, 8:Q.E.D. 29
Natural Deduction: examples Theorem 5: A C, B C |– (A B) C Proof: 1. A Cassumption 2. A CTheorem 2 3. B Cassumption 4. B CTheorem 2 5. A Bassumption 6. Cassumption of indirect proof 7. BED 4, 6 8. AED 2, 6 9. A BIC 7, 8 10. ( A B) (A B)Theorem 3 (de Morgan) 11. (A B)MP 9, 10 contradicts to 5., hence 12. C (assumption of indirect proof is not true) Q.E.D. 30
Natural Deduction: examples Some proofs of FOPL theorems 1)|– x [A x B x ] [ xA x xB x ] Proof: 1. x [A x B x ]assumption 2. x A x assumption 3.A x B x E :1 4.A x E :2 5. B x MP:3,4 6. xB x I :5 Q.E.D. 31
Natural Deduction: examples According to the Deduction Theorem we prove theorems in the form of implication by means of the proof of consequent from antecedent: x [A x B x ] |– [ xA x xB x ] iff x [A x B x ], xA x |– xB x 32
Natural Deduction: examples 2)|– x A x x A x (De Morgan rule) Proof: :1. x A x assumption 2. x A x assumption of indirect proof 3.1. A x hypothesis 3.2. x A x I : 3.1 4. A x x A x II: 3.1, 3.2 5. A x MT: 4,2 6. x A x Z :5contradicts to:1Q.E.D. :1. x A x assumption 2. x A x assumption of indirect proof 3. A c)E :1 4.A c E :2 contradicts to:3 Q.E.D. 33
Natural Deduction: examples Note: In the proof sequence we can introduce a hypothetical assumption H (in this case 3.1.) and derive conclusion C from this hypothetical assumption H (in this case 3.2.). As a regular proof step we then must introduce implication H C (step 4.). According to the Theorem of Deduction this theorem corresponds to two rules of deduction: x A x |– x A x x A x |– x A x 34
Natural Deduction: examples 3)|– x A x x A x (De Morgan rule) Proof: :1. x A x assumption 2.1.A x hypothesis 2.2. x A x Z :2.1 3.A x x A x ZI: 2.1, 2.2 4. A x MT: 3,1 5. x A x Z :4Q.E.D. :1. x A x assumption 2. x A x assumption of indirect proof 3.A c)E : 2 4. A c E : 1contradictss to: 3 Q.E.D. According to the Theorem of Deduction this theorem (3) corresponds to two rules of deduction: x A x |– x A x , x A x |– x A x 35
Existential quantifier elimination Note: In the second part of the proofs ad (2) and (3) the rule of existential quantifier elimination (E ) has been used. This rule is not truth preserving: the formula x A(x) A(c) is not logically valid (cf. Skolem rule in the resolution method: the rule is satifiability preserving). There are two ways of its using correctly: In an indirect proof (satisfiability!) As a an intermediate step that is followed by Introducing again The proofs ad (2) and (3) are examples of the former (indirect proofs). The following proof is an example of the latter: 36
Natural Deduction 4)|– x [A x B x ] [ x A x x B x ] Proof: 1. x [A x B x ]assumption 2. xA x assumption 3.A a E : 2 4.A a B a E : 1 5.B a MP: 3,4 6. xB x I : 5 Q.E.D. Note: this is another example of a correct using the rule E . 37
Natural Deduction 5)|– x [A B x ] A xB x , where A does not contain variable x free Proof: :1. x [A B x ]assumption 2.A B x E : 1 3.A Aaxiom 3.1.A1. hypothesis 3.2.A xB x ZD: 3.1 4.1. A2. hypothesis 4.2.B x ED: 2, 4.1 4.3. xB x I : 4.2 4.4.A xB x ID: 4.3. 5. [A (A xB x )] [ A (A xB x )]II + IC 6.(A A) (A xB x )theorem + MP 5 7.A xB x MP 6, 3 Q.E.D. 38
Natural Deduction 5)|– x [A B x ] A xB x , where A does not contain variable x free Proof: :1.A xB x Assumption, disjunction of hypotheses 2.1.A1. hypothesis 2.2.A B x ID: 2.1 2.3. x [A B x ]I : 2.2 3.A x [A B x ] 4.1. xB x 2. hypothesis 4.2.B x E : 3.1 4.3.A B x ID: 3.2 4.4. x [A B x ]I : 3.3 5. xB x x [A B x ] II 4.1., 4.4. 6. [A xB x ] x [A B x ] Theorem, IC, MP – 3, 5 7. x [A B x ]MP 1, 6Q.E.D. 39
Natural Deduction 6)|– A(x) B xA(x) B Proof: 1.A(x) Bassumption 2. xA(x)assumption 3.A(x)E : 2 5.BMP: 1,2 Q.E.D. This theorem corresponds to the rule: A(x) B |– xA(x) B 40
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https://www.meritnation.com/cbse-class-6/science/living-science/sources-of-food/textbook-solutions/8_2_1169_5543_36282_11
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Living Science Solutions for Class 6 Science Chapter 1 Sources Of Food are provided here with simple step-by-step explanations. These solutions for Sources Of Food are extremely popular among Class 6 students for Science Sources Of Food Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Living Science Book of Class 6 Science Chapter 1 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Living Science Solutions. All Living Science Solutions for class Class 6 Science are prepared by experts and are 100% accurate.
#### Question 1:
Name the sources from where we get the ingredients used in food.
Following are the sources from where we get the ingredients used in food:
(i) Plants
(ii) Animals
(iii) Earth
#### Question 2:
Why are green plants known as producers?
Green plants use sunlight and carbon dioxide from the atmosphere to produce carbohydrates by the process of photosynthesis. Since, plants produce food for themselves, they are known as producers.
#### Question 3:
Name three plants and their parts that we eat.
Example of edible plants are:
1. Banana: The fruit is edible. The centre of stem is also eaten. Less commonly, the flowers of the banana tree is also used as food.
2. Carrot: It is the root of the carrot plant.
3. Rice: The grains of rice that are eaten are the seeds of the rice plant.
#### Question 4:
In what way is a scavenger useful to the environment?
Scavenger consumes dead organisms and prevent them from accumulating in the environment, which may lead to the outbreak of diseases. Therefore, scavengers keep the environment clean. For example, termites consume the remains of dead plants, while vultures consume dead animals.
#### Question 1:
Which of these is obtained from plants?
(a) honey
(b) curd
(c) rice
(d) egg
(c) rice
Rice is obtained directly from plants. Honey is created by bees. Curd is obtained from milk. Eggs are obtained from chicken, ducks or domesticated birds.
#### Question 2:
Which of these is obtained from animals?
(a) pulses
(b) cheese
(c) cereals
(d) sugar
(b) Cheese
Cheese is obtained from milk which is obtained from animals such as cows, goats or buffaloes. However, pulses, cereals and sugar are obtained from plants.
#### Question 3:
Which of these food ingredients do we not get from plants or animals?
(a) salt
(b) honey
(c) milk
(d) wheat
(a) Salt
Salt is obtained neither from animals nor from plants. Salt is either obtained by evaporating sea water or it is mined from salt mines.
#### Question 4:
The first link in all food chains is
(a) herbivores.
(b) carnivores.
(c) plants.
(d) omnivores.
(c) Plants
The first link in any food chain are the plants. All other organisms in the food chain depend upon plants either directly, as in herbivores, or indirectly such as omnivores or carnivores for nutrition.
#### Question 5:
Which of these eats food digested by other animals?
(a) a cow
(b) a lion
(c) a cockroach
(d) a tapeworm
(d) a tapeworm
Parasites eat food that is already digested by the host. The tapeworm is an intestinal parasite affecting human beings. Tapeworm infections are caused most commonly by the consumption of under cooked meat, fish or poultry.
#### Question 6:
Which of these animals does have teeth?
(a) snake
(b) eagle
(c) mosquito
(d) tapeworm
(a) Snake
Snakes have teeth while eagles, mosquitoes and tapeworms do not. All snakes, whether venomous or non-venomous, have teeth to help them hold down and swallow prey. In venomous snakes, there are modified teeth used to inject venom, known as fangs.
#### Question 1:
Name one stem that has food stored in it.
Potato is an example of a stem that has food stored in it.
#### Question 2:
Are humans herbivores, carnivores or omnivores?
Humans are omnivores as they consume both plant and animal products.
#### Question 3:
Some animals usually eat the dead bodies of other animals. What are they called?
Animals that feed upon dead bodies of other animals are known as scavengers.
#### Question 4:
Some food chains end at herbivores. True or false?
True. In case of herbivores with no natural predators, the food chain ends at the herbivore.
#### Question 5:
The chemical substances in food that your body needs are called
The chemical substances in food that your body needs are called nutrients.
#### Question 6:
Do all living things eat the same kind of food?
No, all living things do not eat the same kind of food.
#### Question 5:
Why does a mosquito not have teeth?
Mosquitoes rely upon a liquid diet of either sap or nectar from plants (male mosquitoes) or blood (female mosquitoes carrying eggs). Since mosquitoes do not consume solids, they do not have teeth.
#### Question 6:
We get our food items from plants and animals. Do you agree? Give reasons.
Yes, I agree that we get our food items from plants and animals. All the foods that we eat are either derived from plants such as fruits, grains, vegetables, nuts etc., or they are derived from animals such as meat, poultry, fish, eggs, milk, cheese butter etc.
#### Question 1:
Following are the steps involved in producing honey are:
1. Field bees, fly out from the honeycomb to find flowers and blossoms. They fly from flower to flower and suck out the nectar using their specially adapted tongues. Nectar is stored in special sacs in their bodies.
2. Once the field bees return to the honeycomb, the nectar they bring back is eaten by house bees, which add enzymes from their bodies to the nectar that turns the nectar into honey.
3. The house bees then regurgitate (remove from their bodies by spitting out through their mouths) the honey, which is stored in the cells of the honeycomb.
#### Question 2:
Explain the difference between herbivores, carnivores and omnivores.
The difference between herbivores, carnivores and omnivores are as follows:
Herbivore Carnivore Omnivore Herbivorous animals feed on plants. Carnivorous animals eat the flesh of other animals. An omnivorous animal can eat both plants and also other animals. Herbivorous animals have sharp cutting teeth in front of their mouths and flat grinding teeth at the rear of their mouths Carnivorous animals have well developed sharp teeth, known as canines to help tear the flesh of prey. Carnivorous animals also have claws to hold on to prey. Omnivorous animals have teeth in between that of herbivores and carnivores. They have sharp teeth to tear meat, but also posses flat grinding teeth to crush plants. Examples of herbivores include cows, goats, buffaloes, deer, zebra etc. Examples of carnivores include lions, tigers, eagles, leopards etc. Examples of omnivores include humans, pigs, bears etc.
#### Question 3:
What are the functions of food?
The main functions of food are as follows:
1. Food is a source of energy to the body. When we work with our bodies and perform activities like thinking, running, walking, jumping etc., we use the energy obtained from food.
2. The nutrients contained in food help the body grow and also repair itself by replacing dead and worn out cells.
3. The nutrients contained in food also help the body's immune system to safeguards the body against various diseases.
#### Question 4:
What is a food chain? Explain with an example.
A food chain is a sequence that shows how each living organism gets its food in a particular environment.
Example:
Plants$\to$grasshopper $\to$shrew $\to$owl
1. In the food chain shown, plants prepare food from sunlight, using carbon dioxide from the air by the process of photosynthesis. Since, the plant produces its own food, it is a producer.
2. The grasshopper eats the plants as food to get energy. It is therefore classified as a primary consumer.
3. A secondary consumer such as a shrew eats the grasshopper. As a result, a shrew lies one level above the grasshopper in the food chain.
4. The shrew in turn is food for a tertiary consumer such as an owl. In the example shown, the owl is at the uppermost level of the food chain.
#### Question 5:
How are the teeth of carnivores different from those of herbivores?
Carnivorous animals eat the flesh of other animals, while herbivorous animals eat plants. The teeth of carnivorous animals are adapted to tearing flesh and are usually long and sharp that serve an added function of puncturing vital organs and killing the prey.
The teeth of herbivorous animals are adapted to cutting and tearing leaves from plants and then crushing them. Therefore, herbivores have sharp front teeth to enable them to cut leaves and flat teeth at the rear of their mouth to enable them to crush the leaves or other plant material that is usually quite tough and fibrous.
#### Question 6:
What are parasites? Explain giving two examples.
Parasites are organisms that depend upon other organisms for their food. The organism that a parasite depends upon for food is known as the host. The parasite is usually harmful to the health of the host and can even kill the host. Some examples of parasites are:
1. The Cuscuta plant is a parasitic plant that grows on other plants and inserts its root like projections known as haustoria into the host plant to suck out nutrients from the host plant. The Cuscuta plant does not have well developed leaves and relies mostly upon its host for obtaining food.
2. Mosquitoes, leeches and bed bugs are examples of parasites that survive on blood that they suck from humans and other animals. Since, these parasites live outside the body of the host, they are called ecto-parasites.
#### Question 1:
Both carnivores and parasites depend on other animals for food. In what way is a carnivore different from a parasite?
Carnivores Parasites Carnivores kill their prey to consume them. Parasites may kill their hosts slowly by weakening them. In general however, parasites need not kill their hosts. Carnivores generally do not cause diseases in their prey. Parasites may cause diseases in their hosts. Carnivores are always external to their prey. Parasites may be inside their hosts (endoparasites) or outside their host (ectoparasites). Carnivores can be larger or smaller than their prey. Parasites are generally much smaller than their hosts. Carnivores reproduce very slowly compared to their prey. Parasites reproduce very rapidly compared to their prey. Examples of carnivores include, lions, tigers, leopards, eagles etc. Examples of endoparasites are: intestinal worms such as Ascaris, tapeworm, ringworm, etc. Examples of ectoparasites are mosquitoes, bed bugs, leeches, etc.
#### Question 2:
Humans eat both plants and animals. Which teeth in humans are suitable for tearing flesh?
Humans are omnivores and eat both plant and animal derived foods. Humans have canine teeth that are suitable for tearing flesh. However, canines are not well developed in humans as they are in carnivorous animals such as lions or tigers.
#### Question 3:
A food chain consists of several organisms. Suppose one of the organisms in the chain disappears. What effect can this have on the other organisms in the food chain?
If one of the organisms in the food chain disappears, then the entire food chain will collapse as the flow of the nutrition will get altered and that will eventually cause death of other organisms of that food chain that are at higher levels.
View NCERT Solutions for all chapters of Class 6
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http://www.computer.org/csdl/trans/tc/1983/10/01676139-abs.html
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Subscribe
Issue No.10 - October (1983 vol.32)
pp: 947-952
D. Brand , IBM Thomas J. Watson Research Center
ABSTRACT
A signal in a logical network is called redundant if it can be replaced by a constant without changing the function of the network. Detecting redundancy is important for two reasons: guaranteeing coverage in stuck-fault testing, and simplifying multilevel logic without converting to two levels. In particular, removing redundancy allows simplification in the presence of don't cares. The algorithm for redundancy removal described in this paper has been used successfully for both of the above purposes. It achieves savings in computer resources at the expense of possibly failing to discover some redundancies.
INDEX TERMS
testability, Don't cares, logic synthesis, optimization, redundancy
CITATION
D. Brand, "Redundancy and Don't Cares in Logic Synthesis", IEEE Transactions on Computers, vol.32, no. 10, pp. 947-952, October 1983, doi:10.1109/TC.1983.1676139
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https://infoscience.epfl.ch/record/231346?ln=en
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## Deciphering ambiguous control over fluxes through characterization and reduction of uncertainty
The development of kinetic models is still facing the challenges such as large uncertainties in available data. Uncertainty originating from various sources including metabolite concentration levels, flux values, thermodynamic and kinetic data propagates to the kinetic parameter space and prevents an accurate identification of parameters. The uncertainty in parameters propagates further to the outputs of the corresponding kinetic models, such as control coefficients and time evolutions of metabolic fluxes and concentrations, and it can have deleterious effects on metabolic engineering and synthetic biology decisions. We have introduced a framework recently, iSCHRUNK (in Silico Approach to Characterization and Reduction of Uncertainty in the Kinetic Models), which allows us to characterize uncertainty in the parameters of studied kinetic models and integrate this information into a new population of kinetic models with reduced uncertainty. To this end, iSCHRUNK combines the ORACLE framework with parameter classification techniques. With ORACLE, we first construct a set of large-scale and genome-scale kinetic models that are consistent with the integrated datasets and physicochemical laws. We then employ parameter classification techniques to data-mine the integrated datasets together with the outputs of ORACLE. This way, iSCHRUNK allows us to uncover complex relationships between the integrated data and parameters of kinetic models, and to use the obtained information for constructing an improved set of kinetic models with reduced uncertainty in ORACLE. In this work, we analyzed possible improvements of xylose uptake rate (XTR) in a glucose-xylose co-utilizing S. cerevisiae strain. For this purpose, we computed a population of 200’000 large-scale kinetic models, and we determined the key enzymes controlling XTR. However, large uncertainties due to a limited number of measured flux and metabolite concentration values and lack of data about kinetic parameters led to widespread distributions around zero values for control coefficients of some enzymes such as hexokinase (HXK). We used iSCHRUNK to identify the enzymes and their kinetic parameters that determine negative and positive control of HXK over XTR. Our study showed that by engineering only three saturation states related to two enzymes we could enforce either negative or positive control of HXK over XTR. This result implies that for kinetic modeling of metabolism only a small number of kinetic parameters should be accurately determined and that we can disregard the remaining parameters.
Presented at:
Biochemical & Molecular Engineering XX, Newport Beach, California, USA, July 16-20, 2017
Year:
2017
Keywords:
Laboratories:
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https://p3h.particle.kit.edu/start
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HOMELEGALKIT
# Contact
Spokesperson:
Prof. Kirill Melnikov
Karlsruhe Institute of Technology
[email protected]
Deputy spokesperson:
Prof. Michael Krämer
RWTH Aachen University
[email protected]
Deputy spokesperson:
Prof. Th. Mannel
University of Siegen
[email protected]
Equal Opportunity Officer:
Prof. Malgorzata Worek
RWTH Aachen University
[email protected]
Zahra Donyai
Karlsruhe Institute of Technology
[email protected]
Working Hours: Mon - Tue 9:30-15:30 and Wen 9:30-12:30
# Open positions
Postdoctoral and PhD positions
The Collaborative Research Center invites applications for a number of postdoctoral and Ph.D. positions. More informations can be found here or directly contact principal investigators.
# Welcome
The Collaborative Research Center “Particle Physics Phenomenology after the Higgs Discovery'' is a joint venture of theoretical particle physicists from Karlsruhe Institute of Technology, RWTH Aachen University, University of Siegen and Heidelberg University. It is supported by the German Research Foundation (DFG).
Particle physics has long established itself as an important research discipline focused on understanding Nature at a fundamental level. The current knowledge is summarized in a theory called the Standard Model (SM) of particle physics that describes strong and electroweak interactions. The recent discovery of the Higgs boson formally completes the SM and provides us with a consistent mathematical framework that can be used to describe Nature in fine detail. However, several aspects of the SM force us to raise questions about the foundations of this theory. Many proposed answers to these questions suggest that the SM is a low-energy approximation to a much more fundamental theory that we strive to discover.
Scientists of the CRC will conduct research in phenomenology of elementary particles focusing, in particular, on the physics of Higgs boson, physics of top quarks, electroweak gauge bosons and jets and flavour physics. Our goal is to develop the necessary methodologies to search for physics beyond the Standard Model through precise measurements at the LHC, flavour factories and elsewhere.
# News
16.06.2021 - The second (virtual) session Physicists in Industry will take place on Wednesday, June 16th at 4.00pm. Our second speaker is Dr. Waldemar Martens (Europeas Space Agency, ESA).
26.05.2021 - The annual meeting of the CRC TRR 257 “Particle Physics Phenomenology after the Higgs Discovery'' took place (virtually) in Aachen from May 26th to May 28th. Presentations are available online.
17.02.2021 - We are starting the Physicists in Industry series on career opportunities outside of Academia. The first (virtual) session will be with Marco Baumgartl (BMW Group) on Thursday, February 25th at 4.30pm.
08.10.2020 - The Annual meeting of the Collaborative Research Center took place in Siegen from Oct. 6th to Oct. 8th. The meeting was held in a hybrid (live and zoom) format. Presentations are available online.
03.07.2020 - We would like to welcome Gudrun Heinrich (KIT) and Alexander Lenz (Siegen) as two new principal investigators of the CRC. Within the CRC, Gudrun will develop numerical methods for computing two-loop amplitudes with many mass scales and Alexander will study possible ways to constrain non-perturbative parameters that appear within the heavy quark expansion.
30.06.2020 - We have recently started the new series of talks – the CRC colloquium. The idea is to have CRC PIs talk about their current research. The first talk of the series on “How to GAN” was given by Tilman Plehn (Heidelberg) on June 30th. The second talk on “Precision Flavor physics” will be given by Tobias Huber (Siegen) on July 13th.
# Recent Seminars
Flavour anomalies in rare B decays
Christoph Langenbruch (RWTH Aachen University), 20.07.2021, Aachen
Dark Sectors / feebly interacting particles
Maxim Pospelov, 15.07.2021, Karlsruhe
Semileptonic Penguins and the b to s Anomalies
Tobias Hurth (Johannes Gutenberg Universität Mainz), 13.07.2021, Aachen
Learning to detect top quark interactions
Abideh Jafari, 08.07.2021, Karlsruhe
New Particle Acceleration Methods for High Energy Physics
Ralph Assmann (DESY Hamburg), 06.07.2021, Aachen
Flavourful Windows to New Dynamics
Emmanuel Stamou(TU Dortmund), 05.07.2021, Siegen
Loop integrals and Higgs physics
Li Lin Yang(Peking U.), 28.06.2021, Siegen
# Recent Publications
Stellar Evolution confronts Axion Models
Luca Di Luzio, Marco Fedele, Maurizio Giannotti, Federico Mescia, Enrico Nardi
Tasting Flavoured Majorana Dark Matter
Harun Acaroglu, Monika Blanke
Unveiling Hidden Physics at the LHC
Oliver Fischer, Bruce Mellado, Stefan Antusch, Emanuele Bagnaschi, Shankha Banerjee, Geoff Beck, Ben…
Higgs decay into a lepton pair and a photon: a roadmap to $\mathbf{H\to Z\gamma$
Aliaksei Kachanovich, Ulrich Nierste, and Ivan Ni\v sand\v zi\'c
The complete singlet contribution to the massless quark form factor at three loops in QCD
L. Chen, M. Czakon, M. Niggetiedt
Expansion by regions with pySecDec
G.Heinrich, S.Jahn, S.P.Jones, M.Kerner, F.Langer, V.Magerya, A.Poldaru, J.Schlenk, E.Villa
view all publications
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https://www.science.gov/topicpages/0-9/3-d+mathematical+thermal.html
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Sample records for 3-d mathematical thermal
1. 3D Multifunctional Ablative Thermal Protection System
NASA Technical Reports Server (NTRS)
Feldman, Jay; Venkatapathy, Ethiraj; Wilkinson, Curt; Mercer, Ken
2015-01-01
NASA is developing the Orion spacecraft to carry astronauts farther into the solar system than ever before, with human exploration of Mars as its ultimate goal. One of the technologies required to enable this advanced, Apollo-shaped capsule is a 3-dimensional quartz fiber composite for the vehicle's compression pad. During its mission, the compression pad serves first as a structural component and later as an ablative heat shield, partially consumed on Earth re-entry. This presentation will summarize the development of a new 3D quartz cyanate ester composite material, 3-Dimensional Multifunctional Ablative Thermal Protection System (3D-MAT), designed to meet the mission requirements for the Orion compression pad. Manufacturing development, aerothermal (arc-jet) testing, structural performance, and the overall status of material development for the 2018 EM-1 flight test will be discussed.
2. Dynamics of 3D isolated thermal filaments
Walkden, N. R.; Easy, L.; Militello, F.; Omotani, J. T.
2016-11-01
Simulations have been carried out to establish how electron thermal physics, introduced in the form of a dynamic electron temperature, affects isolated filament motion and dynamics in 3D. It is found that thermal effects impact filament motion in two major ways when the pressure perturbation within the filament is supported primarily through a temperature increase as opposed to density: they lead to a strong increase in filament propagation in the bi-normal direction and a significant decrease in net radial propagation. Both effects arise from the temperature dependence of the sheath current which leads to a non-uniform floating potential, with the latter effect supplemented by faster pressure loss. The reduction in radial velocity can only occur when the filament cross-section loses angular symmetry. The behaviour is observed across different filament sizes and suggests that filaments with much larger temperature perturbations than density perturbations are more strongly confined to the near SOL region.
3. TEMPEST. Transient 3-D Thermal-Hydraulic
SciTech Connect
Eyler, L.L.
1992-01-31
TEMPEST is a transient, three-dimensional, hydrothermal program that is designed to analyze a range of coupled fluid dynamic and heat transfer systems of particular interest to the Fast Breeder Reactor (FBR) thermal-hydraulic design community. The full three-dimensional, time-dependent equations of motion, continuity, and heat transport are solved for either laminar or turbulent fluid flow, including heat diffusion and generation in both solid and liquid materials. The equations governing mass, momentum, and energy conservation for incompressible flows and small density variations (Boussinesq approximation) are solved using finite-difference techniques. Analyses may be conducted in either cylindrical or Cartesian coordinate systems. Turbulence is treated using a two-equation model. Two auxiliary plotting programs, SEQUEL and MANPLOT, for use with TEMPEST output are included. SEQUEL may be operated in batch or interactive mode; it generates data required for vector plots, contour plots of scalar quantities, line plots, grid and boundary plots, and time-history plots. MANPLOT reads the SEQUEL-generated data and creates the hardcopy plots. TEMPEST can be a valuable hydrothermal design analysis tool in areas outside the intended FBR thermal-hydraulic design community.
4. Thermal 3D modeling system based on 3-view geometry
Yu, Sunjin; Kim, Joongrock; Lee, Sangyoun
2012-11-01
In this paper, we propose a novel thermal three-dimensional (3D) modeling system that includes 3D shape, visual, and thermal infrared information and solves a registration problem among these three types of information. The proposed system consists of a projector, a visual camera and, a thermal camera (PVT). To generate 3D shape information, we use a structured light technique, which consists of a visual camera and a projector. A thermal camera is added to the structured light system in order to provide thermal information. To solve the correspondence problem between the three sensors, we use three-view geometry. Finally, we obtain registered PVT data, which includes visual, thermal, and 3D shape information. Among various potential applications such as industrial measurements, biological experiments, military usage, and so on, we have adapted the proposed method to biometrics, particularly for face recognition. With the proposed method, we obtain multi-modal 3D face data that includes not only textural information but also data regarding head pose, 3D shape, and thermal information. Experimental results show that the performance of the proposed face recognition system is not limited by head pose variation which is a serious problem in face recognition.
5. Reduction of thermal conductivity by nanoscale 3D phononic crystal.
PubMed
Yang, Lina; Yang, Nuo; Li, Baowen
2013-01-01
We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal conductivity decreases as the period length and mass ratio increases. The phonon dispersion curves show an obvious decrease of group velocities in 3D phononic crystals. The phonon's localization and band gap is also clearly observed in spectra of normalized inverse participation ratio in nanoscale 3D phononic crystal.
6. Reduction of Thermal Conductivity by Nanoscale 3D Phononic Crystal
PubMed Central
Yang, Lina; Yang, Nuo; Li, Baowen
2013-01-01
We studied how the period length and the mass ratio affect the thermal conductivity of isotopic nanoscale three-dimensional (3D) phononic crystal of Si. Simulation results by equilibrium molecular dynamics show isotopic nanoscale 3D phononic crystals can significantly reduce the thermal conductivity of bulk Si at high temperature (1000 K), which leads to a larger ZT than unity. The thermal conductivity decreases as the period length and mass ratio increases. The phonon dispersion curves show an obvious decrease of group velocities in 3D phononic crystals. The phonon's localization and band gap is also clearly observed in spectra of normalized inverse participation ratio in nanoscale 3D phononic crystal. PMID:23378898
7. Communicating Experience of 3D Space: Mathematical and Everyday Discourse
ERIC Educational Resources Information Center
2012-01-01
In this article we consider data arising from student-teacher-researcher interactions taking place in the context of an experimental teaching program making use of multiple modes of communication and representation to explore three-dimensional (3D) shape. As teachers/researchers attempted to support student use of a logo-like formal language for…
8. Role of Interaction in Enhancing the Epistemic Utility of 3D Mathematical Visualizations
ERIC Educational Resources Information Center
Liang, Hai-Ning; Sedig, Kamran
2010-01-01
Many epistemic activities, such as spatial reasoning, sense-making, problem solving, and learning, are information-based. In the context of epistemic activities involving mathematical information, learners often use interactive 3D mathematical visualizations (MVs). However, performing such activities is not always easy. Although it is generally…
9. Wear Analysis of Thermal Spray Coatings on 3D Surfaces
Tillmann, W.; Luo, W.; Selvadurai, U.
2014-01-01
Even though the application of thermal spray coatings on complex geometries gained a greater interest in the last decade, the effect of different geometrical features on the wear behavior is still ill-defined. In this study, the wear resistance of FTC-FeCSiMn coated 3D surfaces was investigated. The wear test was carried out by means of two innovative testing procedures. The first test is a Pin-on-Tubes test where the rotating motion is realized by a lathe chuck. The specimens in the second test were fixed on the table and a robot arm operated the pin. This wear test was applied on specimens with concave or convex surfaces. The residual stresses, which were determined by means of an incremental hole-drilling method, show a dependency on the substrate geometry. The obtained stresses were put in relation to the different radii. After the wear test, a 3D-profilometer determined the wear volume and the sections of the coatings were characterized by a scanning electron microscope. The results indicate that the wear resistance is strongly influenced by the geometry of the substrate.
10. A Comprehensive 3D Mathematical Model of the Electroslag Remelting Process
Wang, Xiaohua; Li, Ying
2015-08-01
A comprehensive 3D mathematical model was proposed to predict the electromagnetic field, the multiphase flow field, the temperature field, and the pool profile of an industrial electroslag remelting (ESR) system. Especially, the metal droplets formation and falling in the slag pool during the ESR process are taken into account using the volume of fluid method. In addition, the electromagnetic and solidification phenomena are modeled using the magnetic vector potential method and the enthalpy-porosity method, respectively. The predicted results were found to be in good agreement with experimental measurements, regarding the magnetic flux density, the pool profile, the energy consumption, and the melt rate. And the model developed in the present work has been proved to be a powerful tool to provide a useful insight into the multi-physical phenomena in the ESR system. The results show that the Joule heating is mainly distributed in the slag pool due to the lower electrical conductivity of slag, and provides the thermal energy for melting the electrode. The molten metal on the conical electrode surface is washed away by the Lorentz force and the gravity force and gradually accumulates at the electrode tip. When the drop at the electrode tip reaches the critical size, the small droplets form due to the necking effect and depart from the conical electrode tip. In the slag pool, there are two axisymmetric vortexes with downward flows under the conical electrode tip, where the Lorentz force and the falling droplets are dominant, and another two axisymmetric vortexes with downward flows near the mold surface, where the thermal buoyancy is dominant. However, in the metal pool, there are only two vortexes with downward flows at the solidification front, where a high thermal gradient exists. The slag is significantly hotter and more uniform than the metal, because of an abundant of Joule heating and intensive turbulence in the slag pool. The molten metal is directionally
11. COMMIX-1B. 3-D Single-Phase Thermal Hydraulics
SciTech Connect
Wildman, D.J.
1986-01-31
COMMIX-1B is designed to perform steady-state or transient, single-phase, three-dimensional analysis of fluid flow with heat transfer in a single-component or multicomponent system. The program was developed for the analysis of heat transfer and fluid flow processes in a nuclear reactor system; however, it can easily be applied to non-nuclear systems requiring heat transfer and/or fluid flow analysis. COMMIX-1B solves the conservation equations of mass, momentum, and energy, and transport equations of turbulence parameters and provides detailed local velocity, temperature, and pressure fields for the problem under consideration. It is capable of solving thermal-hydraulic problems involving either a single component, such as a rod bundle, reactor plenum, piping system, heat exchanger, etc., or a multicomponent system that is a combination of these components.
12. The cognitive apprenticeship theory for the teaching of mathematics in an online 3D virtual environment
2013-03-01
Research spanning two decades shows that there is a continuing development of 3D virtual worlds and investment in such environments for educational purposes. Research stresses the need for these environments to be well-designed and for suitable pedagogies to be implemented in the teaching practice in order for these worlds to be fully effective. To this end, we propose a pedagogical framework based on the cognitive apprenticeship for deriving principles and guidelines to inform the design, development and use of a 3D virtual environment. This study examines how the use of a 3D virtual world facilitates the teaching of mathematics in primary education by combining design principles and guidelines based on the Cognitive Apprenticeship Theory and the teaching methods that this theory introduces. We focus specifically on 5th and 6th grade students' engagement (behavioral, affective and cognitive) while learning fractional concepts over a period of two class sessions. Quantitative and qualitative analyses indicate considerable improvement in the engagement of the students who participated in the experiment. This paper presents the findings regarding students' cognitive engagement in the process of comprehending basic fractional concepts - notoriously hard for students to master. The findings are encouraging and suggestions are made for further research.
13. 3D thermal medical image visualization tool: Integration between MRI and thermographic images.
PubMed
Abreu de Souza, Mauren; Chagas Paz, André Augusto; Sanches, Ionildo Jóse; Nohama, Percy; Gamba, Humberto Remigio
2014-01-01
Three-dimensional medical image reconstruction using different images modalities require registration techniques that are, in general, based on the stacking of 2D MRI/CT images slices. In this way, the integration of two different imaging modalities: anatomical (MRI/CT) and physiological information (infrared image), to generate a 3D thermal model, is a new methodology still under development. This paper presents a 3D THERMO interface that provides flexibility for the 3D visualization: it incorporates the DICOM parameters; different color scale palettes at the final 3D model; 3D visualization at different planes of sections; and a filtering option that provides better image visualization. To summarize, the 3D thermographc medical image visualization provides a realistic and precise medical tool. The merging of two different imaging modalities allows better quality and more fidelity, especially for medical applications in which the temperature changes are clinically significant.
14. Optimisation of trench isolated bipolar transistors on SOI substrates by 3D electro-thermal simulations
Nigrin, S.; Armstrong, G. A.; Kranti, A.
2007-09-01
This paper provides a comprehensive analysis of thermal resistance of trench isolated bipolar transistors on SOI substrates based on 3D electro-thermal simulations calibrated to experimental data. The impact of emitter length, width, spacing and number of emitter fingers on thermal resistance is analysed in detail. The results are used to design and optimise transistors with minimum thermal resistance and minimum transistor area.
15. The Effect of 3D Virtual Learning Environment on Secondary School Third Grade Students' Attitudes toward Mathematics
ERIC Educational Resources Information Center
Simsek, Irfan
2016-01-01
With this research, in Second Life environment which is a three dimensional online virtual world, it is aimed to reveal the effects of student attitudes toward mathematics courses and design activities which will enable the third grade students of secondary school (primary education seventh grade) to see the 3D objects in mathematics courses in a…
16. A 3D mathematical model for the horizontal anode baking furnace
SciTech Connect
Kocaefe, Y.S.; Dernedde, E.; Kocaefe, D.; Ouellet, R.; Jiao, Q.; Crowell, W.F.
1996-10-01
In the aluminum industry, carbon anodes are baked in large horizontal or vertical ring-type furnaces. The anode quality depends strongly on the baking conditions (heating rate, soaking time and final anode temperature). A three-dimensional mathematical model has been developed for a horizontal anode baking furnace to assess the effects of different parameters on the baking process and to improve the furnace operation and design at Noranda Aluminum Smelter in New Madrid, Missouri. The commercial CFD code CFDS-FLOW3D is used to solve the governing differential equations. The model gives the temperature, velocity and concentration distributions in the flue, and the variation of the temperature distribution with time in the pit. In this paper, a description of the 3D model for the horizontal anode baking furnace will be given. Some of the results from a case study will also be presented. The results show clearly the importance of flue geometry on the gas flow distribution in the flue and the heat transfer to the anodes.
17. Development of 3D Woven Ablative Thermal Protection Systems (TPS) for NASA Spacecraft
NASA Technical Reports Server (NTRS)
Feldman, Jay D.; Ellerby, Don; Stackpoole, Mairead; Peterson, Keith; Venkatapathy, Ethiraj
2015-01-01
The development of a new class of thermal protection system (TPS) materials known as 3D Woven TPS led by the Entry Systems and Technology Division of NASA Ames Research Center (ARC) will be discussed. This effort utilizes 3D weaving and resin infusion technologies to produce heat shield materials that are engineered and optimized for specific missions and requirements. A wide range of architectures and compositions have been produced and preliminarily tested to prove the viability and tailorability of the 3D weaving approach to TPS.
18. Anisotropic thermal expansion of a 3D metal–organic framework with hydrophilic and hydrophobic pores
SciTech Connect
Kondo, Atsushi Maeda, Kazuyuki
2015-01-15
A 3D flexible metal–organic framework (MOF) with 1D hydrophilic and hydrophobic pores shows anisotropic thermal expansion with relatively large thermal expansion coefficient (α{sub a}=−21×10{sup −6} K{sup −1} and α{sub c}=79×10{sup −6} K{sup −1}) between 133 K and 383 K. Temperature change gives deformation of both pores, which expand in diameter and elongate in length on cooling and vice versa. The thermally induced structural change should be derived from a unique framework topology like “lattice fence”. Silica accommodation changes not only the nature of the MOF but also thermal responsiveness of the MOF. Since the hydrophobic pores in the material are selectively blocked by the silica, the MOF with the silica is considered as a hydrophilic microporous material. Furthermore, inclusion of silica resulted in a drastic pore contraction in diameter and anisotropically changed the thermal responsiveness of the MOF. - Graphical abstract: A 3D metal–organic framework with hydrophilic and hydrophobic pores shows anisotropic thermal expansion behavior. The influence of silica filler in the hydrophobic pore was investigated. - Highlights: • Thermally induced structural change of a 3D MOF with a lattice fence topology was investigated. • The structural change was analyzed by synchrotron X-ray diffraction patterns. • Temperature change induces anisotropic thermal expansion/contraction of the MOF. • Silica inclusion anisotropically changes the thermal responsiveness of the MOF.
19. A 3D gravity and thermal model for the Barents Sea and Kara Sea
Klitzke, Peter; Sippel, Judith; Faleide, Jan Inge; Scheck-Wenderoth, Magdalena
2016-08-01
In the frame of this study, we investigate the lithosphere-scale 3D physical state of the Barents Sea and Kara Sea region. Therefore, we test an existing 3D structural model against the gravitational field by considering the heterogeneous upper mantle to further assess the structural and density configuration of the continental crystalline crust. The resulting 3D density configuration of the crust is discussed in terms of its relationships with the spatial distribution of tectonically different domains. In addition, it provides the base for a lithology-controlled parameterisation of the crust with thermal properties to calculate the 3D conductive thermal field. The deeper thermal field is controlled by the depth configuration of the lithosphere-asthenosphere boundary. Accordingly, deeper isotherms such as the 450 °C isotherm deepen from below the rifted SW Barents Sea towards the intracratonic basins of the eastern Barents Sea and Kara Sea, indicating an increase of the lithospheric strength in the same direction. Temperature measurements of the upper 800 m below the SW Barents Sea reveal an increased thermal gradient which cannot be reproduced by a steady-state 3D conductive model alone. Beside fault-induced fluid flow to be active there, an alternative scenario could involve a phase of subsidence long enough to increase the temperature of the upper 800 m, followed by an uplift and erosion phase that prevented the positive thermal anomaly to propagate towards larger depths. The final lithosphere-scale 3D model is the first to integrate the geological, density and thermal configuration of the entire Barents Sea and Kara Sea region and hence provides an ideal base for future thermomechanical studies addressing, for instance, questions on the present-day, past and future relationships between lithospheric strength and deformation.
20. Estimation of the thermal conductivity of hemp based insulation material from 3D tomographic images
El-Sawalhi, R.; Lux, J.; Salagnac, P.
2016-08-01
In this work, we are interested in the structural and thermal characterization of natural fiber insulation materials. The thermal performance of these materials depends on the arrangement of fibers, which is the consequence of the manufacturing process. In order to optimize these materials, thermal conductivity models can be used to correlate some relevant structural parameters with the effective thermal conductivity. However, only a few models are able to take into account the anisotropy of such material related to the fibers orientation, and these models still need realistic input data (fiber orientation distribution, porosity, etc.). The structural characteristics are here directly measured on a 3D tomographic image using advanced image analysis techniques. Critical structural parameters like porosity, pore and fiber size distribution as well as local fiber orientation distribution are measured. The results of the tested conductivity models are then compared with the conductivity tensor obtained by numerical simulation on the discretized 3D microstructure, as well as available experimental measurements. We show that 1D analytical models are generally not suitable for assessing the thermal conductivity of such anisotropic media. Yet, a few anisotropic models can still be of interest to relate some structural parameters, like the fiber orientation distribution, to the thermal properties. Finally, our results emphasize that numerical simulations on 3D realistic microstructure is a very interesting alternative to experimental measurements.
1. Thermal Performance Mapping of Direct Liquid Cooled 3d Chip Stacks
Geisler, Karl J. L.; Bar-Cohen, Avram
Chip stacks are a crucial building block in advanced 3D microsystem architectures and can accommodate shorter interconnect distances between devices, leading to reduced power dissipation and improved electrical performance. Although enhanced conduction can serve to transfer the dissipated heat to the top and sides of the package and/or down to the underlying PCB, effective thermal management of stacked chips remains a most difficult challenge. Immersion cooling techniques, which provide convective and/or ebullient heat transfer, along with buoyant fluid flow, in the narrow gaps separating adjacent chips, are a most promising alternative to conduction cooling of threedimensional chip stacks. Application of the available theories, correlations, and experimental data are shown to reveal that passive immersion cooling--relying on natural convection and/or pool boiling--could provide the requisite thermal management capability for 3D chip stacks anticipated for use in much of the portable equipment category. Alternatively, pumped flow of dielectric liquids through the microgaps in 3D stacks, providing single phase and/or flow boiling heat absorption, could meet many of the most extreme thermal management requirements for high-performance 3D microsystems.
2. 3D structure and conductive thermal field of the Upper Rhine Graben
Freymark, Jessica; Sippel, Judith; Scheck-Wenderoth, Magdalena; Bär, Kristian; Stiller, Manfred; Fritsche, Johann-Gerhard; Kracht, Matthias
2016-04-01
The Upper Rhine Graben (URG) was formed as part of the European Cenozoic Rift System in a complex extensional setting. At present-day, it has a large socioeconomic relevance as it provides a great potential for geothermal energy production in Germany and France. For the utilisation of this energy resource it is crucial to understand the structure and the observed temperature anomalies in the rift basin. In the framework of the EU-funded "IMAGE" project (Integrated Methods for Advanced Geothermal Exploration), we apply a data-driven numerical modelling approach to quantify the processes and properties controlling the spatial distribution of subsurface temperatures. Typically, reservoir-scale numerical models are developed for predictions on the subsurface hydrothermal conditions and for reducing the risk of drilling non-productive geothermal wells. One major problem related to such models is setting appropriate boundary conditions that define, for instance, how much heat enters the reservoir from greater depths. Therefore, we first build a regional lithospheric-scale 3D structural model, which covers not only the entire URG but also adjacent geological features like the Black Forest and the Vosges Mountains. In particular, we use a multidisciplinary dataset (e.g. well data, seismic reflection data, existing structural models, gravity) to construct the geometries of the sediments, the crust and the lithospheric mantle that control the spatial distribution of thermal conductivity and radiogenic heat production and hence temperatures. By applying a data-based and lithology-dependent parameterisation of this lithospheric-scale 3D structural model and a 3D finite element method, we calculate the steady-state conductive thermal field for the entire region. Available measured temperatures (down to depths of up to 5 km) are considered to validate the 3D thermal model. We present major characteristics of the lithospheric-scale 3D structural model and results of the 3D
3. Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions
SciTech Connect
McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K; Maienschein, J L
2001-05-29
Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled thermal, mechanical, and chemical behavior of heating, ignition, and explosion in cookoff tests. In our application, a standard three-step step model is selected for the chemical kinetics. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. Materials characterization measurements are given for thermal expansion, heat capacity, shear modulus, bulk modulus, and One-Dimensional-Time-to-Explosion (ODTX). These measurements and those of the other project participants are used to determine parameters in the ALE3D chemical, mechanical, and thermal models. Time-dependent, two-dimensional results are given for the temperature and material expansion. The results show predicted cookoff temperatures slightly higher than the measured values.
4. Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions
SciTech Connect
McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K; Maienschein, J L
2001-08-21
Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled thermal, mechanical, and chemical behavior of heating, ignition, and explosion in cookoff tests. In our application, a standard three-step step model is selected for the chemical kinetics. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. Materials characterization measurements are given for thermal expansion, heat capacity, shear modulus, bulk modulus, and One-Dimensional-Time-to-Explosion (ODTX). These measurements and those of the other project participants are used to determine parameters in the ALE3D chemical, mechanical, and thermal models. Time-dependent, two-dimensional results are given for the temperature and material expansion. The results show predicted cookoff temperatures slightly higher than the measured values.
5. Thermal characterization of a liquid resin for 3D printing using photothermal techniques
Jiménez-Pérez, José L.; Pincel, Pavel Vieyra; Cruz-Orea, Alfredo; Correa-Pacheco, Zormy N.
2016-05-01
Thermal properties of a liquid resin were studied by thermal lens spectrometry (TLS) and open photoacoustic cell (OPC), respectively. In the case of the TLS technique, the two mismatched mode experimental configuration was used with a He-Ne laser, as a probe beam and an Argon laser was used as the excitation source. The characteristic time constant of the transient thermal lens was obtained by fitting the theoretical expression to the experimental data in order to obtain the thermal diffusivity ( α) of the resin. On the other hand, the sample thermal effusivity ( e) was obtained by using the OPC technique. In this technique, an Argon laser was used as the excitation source and was operated at 514 nm with an output power of 30 mW. From the obtained thermal diffusivity ( α) and thermal effusivity ( e) values, the thermal conductivity ( k) and specific heat capacity per unit volume ( ρc) of resin were calculated through the relationships k = e( α)1/2 and ρc = e/( α)1/2. The obtained thermal parameters were compared with the thermal parameters of the literature. To our knowledge, the thermal characterization of resin has not been reported until now. The present study has applications in laser stereo-lithography to manufacture 3D printing pieces.
6. Comparison of the LLNL ALE3D and AKTS Thermal Safety Computer Codes for Calculating Times to Explosion in ODTX and STEX Thermal Cookoff Experiments
SciTech Connect
Wemhoff, A P; Burnham, A K
2006-04-05
Cross-comparison of the results of two computer codes for the same problem provides a mutual validation of their computational methods. This cross-validation exercise was performed for LLNL's ALE3D code and AKTS's Thermal Safety code, using the thermal ignition of HMX in two standard LLNL cookoff experiments: the One-Dimensional Time to Explosion (ODTX) test and the Scaled Thermal Explosion (STEX) test. The chemical kinetics model used in both codes was the extended Prout-Tompkins model, a relatively new addition to ALE3D. This model was applied using ALE3D's new pseudospecies feature. In addition, an advanced isoconversional kinetic approach was used in the AKTS code. The mathematical constants in the Prout-Tompkins code were calibrated using DSC data from hermetically sealed vessels and the LLNL optimization code Kinetics05. The isoconversional kinetic parameters were optimized using the AKTS Thermokinetics code. We found that the Prout-Tompkins model calculations agree fairly well between the two codes, and the isoconversional kinetic model gives very similar results as the Prout-Tompkins model. We also found that an autocatalytic approach in the beta-delta phase transition model does affect the times to explosion for some conditions, especially STEX-like simulations at ramp rates above 100 C/hr, and further exploration of that effect is warranted.
7. 3D thermal modeling of TRISO fuel coupled with neutronic simulation
SciTech Connect
Hu, Jianwei; Uddin, Rizwan
2010-01-01
The Very High Temperature Gas Reactor (VHTR) is widely considered as one of the top candidates identified in the Next Generation Nuclear Power-plant (NGNP) Technology Roadmap under the U.S . Depanment of Energy's Generation IV program. TRlSO particle is a common element among different VHTR designs and its performance is critical to the safety and reliability of the whole reactor. A TRISO particle experiences complex thermo-mechanical changes during reactor operation in high temperature and high burnup conditions. TRISO fuel performance analysis requires evaluation of these changes on micro scale. Since most of these changes are temperature dependent, 3D thermal modeling of TRISO fuel is a crucial step of the whole analysis package. In this paper, a 3D numerical thermal model was developed to calculate temperature distribution inside TRISO and pebble under different scenarios. 3D simulation is required because pebbles or TRISOs are always subjected to asymmetric thermal conditions since they are randomly packed together. The numerical model was developed using finite difference method and it was benchmarked against ID analytical results and also results reported from literature. Monte-Carlo models were set up to calculate radial power density profile. Complex convective boundary condition was applied on the pebble outer surface. Three reactors were simulated using this model to calculate temperature distribution under different power levels. Two asymmetric boundary conditions were applied to the pebble to test the 3D capabilities. A gas bubble was hypothesized inside the TRISO kernel and 3D simulation was also carried out under this scenario. Intuition-coherent results were obtained and reported in this paper.
8. Multiscale 3D manufacturing: combining thermal extrusion printing with additive and subtractive direct laser writing
Malinauskas, Mangirdas; Lukoševičius, Laurynas; MackevičiÅ«tÄ--, DovilÄ--; BalčiÅ«nas, Evaldas; RekštytÄ--, Sima; Paipulas, Domas
2014-05-01
A novel approach for efficient manufacturing of three-dimensional (3D) microstructured scaffolds designed for cell studies and tissue engineering applications is presented. A thermal extrusion (fused filament fabrication) 3D printer is employed as a simple and low-cost tabletop device enabling rapid materialization of CAD models out of biocompatible and biodegradable polylactic acid (PLA). Here it was used to produce cm- scale microporous (pore size varying from 100 to 400 µm) scaffolds. The fabricated objects were further laser processed in a direct laser writing (DLW) subtractive (ablation) and additive (lithography) manners. The first approach enables precise surface modification by creating micro-craters, holes and grooves thus increasing the surface roughness. An alternative way is to immerse the 3D PLA scaffold in a monomer solution and use the same DLW setup to refine its inner structure by fabricating dots, lines or a fine mesh on top as well as inside the pores of previously produced scaffolds. The DLW technique is empowered by ultrafast lasers - it allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. Structure geometry on macro- to micro- scales could be finely tuned by combining these two fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro- featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of ms, microfluidics, microoptics and many others.
9. Extreme low thermal conductivity in nanoscale 3D Si phononic crystal with spherical pores.
PubMed
Yang, Lina; Yang, Nuo; Li, Baowen
2014-01-01
In this work, we propose a nanoscale three-dimensional (3D) Si phononic crystal (PnC) with spherical pores, which can reduce the thermal conductivity of bulk Si by a factor up to 10,000 times at room temperature. Thermal conductivity of Si PnCs depends on the porosity, for example, the thermal conductivity of Si PnCs with porosity 50% is 300 times smaller than that of bulk Si. The phonon participation ratio spectra demonstrate that more phonons are localized as the porosity increases. The thermal conductivity is insensitive to the temperature changes from room temperature to 1100 K. The extreme-low thermal conductivity could lead to a larger value of ZT than unity as the periodic structure affects very little the electric conductivity.
10. FDSOI bottom MOSFETs stability versus top transistor thermal budget featuring 3D monolithic integration
Fenouillet-Beranger, C.; Previtali, B.; Batude, P.; Nemouchi, F.; Cassé, M.; Garros, X.; Tosti, L.; Rambal, N.; Lafond, D.; Dansas, H.; Pasini, L.; Brunet, L.; Deprat, F.; Grégoire, M.; Mellier, M.; Vinet, M.
2015-11-01
To set up specification for 3D monolithic integration, for the first time, the thermal stability of state-of-the-art FDSOI (Fully Depleted SOI) transistors electrical performance is quantified. Post fabrication annealings are performed on FDSOI transistors to mimic the thermal budget associated to top layer processing. Degradation of the silicide for thermal treatments beyond 400 °C is identified as the main responsible for performance degradation for PMOS devices. For the NMOS transistors, arsenic (As) and phosphorus (P) dopants deactivation adds up to this effect. By optimizing both the n-type extension implantations and the bottom silicide process, thermal stability of FDSOI can be extended to allow relaxing upwards the thermal budget authorized for top transistors processing.
11. Thermal and mechanical properties of selected 3D printed thermoplastics in the cryogenic temperature regime
Weiss, K.-P.; Bagrets, N.; Lange, C.; Goldacker, W.; Wohlgemuth, J.
2015-12-01
Insulating materials for use in cryogenic boundary conditions are still limited to a proved selection as Polyamid, Glasfiber reinforced resins, PEEK, Vespel etc. These materials are usually formed to parts by mechanical machining or sometimes by cast methods. Shaping complex geometries in one piece is limited. Innovative 3D printing is now an upcoming revolutionary technology to construct functional parts from a couple of thermoplastic materials as ABS, Nylon and others which possess quite good mechanical stability and allow realizing very complex shapes with very subtle details. Even a wide range of material mixtures is an option and thermal treatments can be used to finish the material structure for higher performance. The use of such materials in cryogenic environment is very attractive but so far poor experience exists. In this paper, first investigations of the thermal conductivity, expansion and mechanical strength are presented for a few selected commercial 3D material samples to evaluate their application prospects in the cryogenic temperature regime.
12. 3D-computation of a thermal process in a superconducting coil
SciTech Connect
Netter, D.; Leveque, J.; Rezzoug, A.; Caron, J.P.; Sargos, F.M.
1995-11-01
This study deals with the resistive zone propagation in a superconducting coil during a quench, taking into account both the flux density distribution and the anisotropy of the thermal parameters. A Finite Difference Method is used to solve the heat diffusion equation and the flux density is calculated by means of a semi-analytical method. The 3-D model is suitable to describe the quench of thick coils and it can be applied to the study of thermal stability. As an application, a 10 kJ-solenoid is studied.
13. Peach Bottom 2 Turbine Trip Simulation Using TRAC-BF1/COS3D, a Best-Estimate Coupled 3-D Core and Thermal-Hydraulic Code System
SciTech Connect
Ui, Atsushi; Miyaji, Takamasa
2004-10-15
The best-estimate coupled three-dimensional (3-D) core and thermal-hydraulic code system TRAC-BF1/COS3D has been developed. COS3D, based on a modified one-group neutronic model, is a 3-D core simulator used for licensing analyses and core management of commercial boiling water reactor (BWR) plants in Japan. TRAC-BF1 is a plant simulator based on a two-fluid model. TRAC-BF1/COS3D is a coupled system of both codes, which are connected using a parallel computing tool. This code system was applied to the OECD/NRC BWR Turbine Trip Benchmark. Since the two-group cross-section tables are provided by the benchmark team, COS3D was modified to apply to this specification. Three best-estimate scenarios and four hypothetical scenarios were calculated using this code system. In the best-estimate scenario, the predicted core power with TRAC-BF1/COS3D is slightly underestimated compared with the measured data. The reason seems to be a slight difference in the core boundary conditions, that is, pressure changes and the core inlet flow distribution, because the peak in this analysis is sensitive to them. However, the results of this benchmark analysis show that TRAC-BF1/COS3D gives good precision for the prediction of the actual BWR transient behavior on the whole. Furthermore, the results with the modified one-group model and the two-group model were compared to verify the application of the modified one-group model to this benchmark. This comparison shows that the results of the modified one-group model are appropriate and sufficiently precise.
14. 3D thermal analysis of rectangular microscale inorganic light-emitting diodes in a pulsed operation
Cui, Y.; Bian, Z.; Li, Y.; Xing, Y.; Song, J.
2016-10-01
Microscale inorganic light-emitting diodes (µ-ILEDs) have attracted much attention due to their excellent performance in biointegrated applications such as optogenetics. The thermal behaviors of µ-ILEDs are critically important since a certain temperature increase may degrade the LED performance and cause tissue lesion. The µ-ILEDs in a pulsed operation offer an advantage in thermal management. In this paper, a 3D analytic model, as validated by finite element analysis, is developed to study the thermal response of rectangular µ-ILEDs in a pulsed operation. A scaling law for the maximum normalized temperature increase of rectangular µ-ILEDs in terms of non-dimensional parameters is established. The influences of geometric (i.e. shape factor) and loading parameters (e.g. duty cycle and period) on the temperature increase are systematically investigated. These results are very helpful in designing µ-ILEDs by providing guidelines to avoid adverse thermal effects.
15. 3D finite element analysis on esthetic indirect dental restorations under thermal and mechanical loading.
PubMed
Cornacchia, Tulimar P M; Las Casas, Estevam B; Cimini, Carlos Alberto; Peixoto, Rodrigo G
2010-11-01
Thermo-mechanical finite element analyses in 3-D models are described for determination of the stress levels due to thermal and mechanical loads in a healthy and restored tooth. Transient thermo-mechanical analysis simulating the ingestion of cold and hot drinks was performed to determine the temperature distribution in the models of the teeth, followed by linear elastic stress analyses. The thermal loads were applied on the occlusal and lingual surfaces. Subsequently, coupled variation of the temperature and mastication loading was considered. The vertical loading was distributed at occlusal points, adding up to 180 N. Maximum stresses were verified in resin restoration under thermal loads. When studying coupled effect of mechanical loading with that arising from thermal effects, higher tensile stress values occurred in porcelain restorations, especially at the restoration-dentin interface. Regions of high tensile stress were detected and their possible clinical significance with respect to restoration damage and microleakage were discussed.
16. Modelling a crime scene in 3D and adding thermal information
van Iersel, Miranda; Veerman, Henny; van der Mark, Wannes
2009-09-01
Once a crime has been perpetrated, forensic traces will only be persevered in the crime scene for a limited time frame. It is therefore necessary to record a crime scene meticulously. Usually, photographs and/or videos are taken at the scene to document it, so that later on one will know the exact place of an object. Another possibility is to construct a three dimensional (3D) model of the crime scene. A 3D model has the advantage that you can change the perspective and view the scene from all directions. We use a stereo camera to record the crime scene and use these images to construct a 3D model. A drawback of conventional (color) cameras is that they only capture features that belong to the visible part of electromagnetic spectrum. Interesting traces with strong signatures in other parts of the spectrum could be overlooked. For example; has a lamp or computer screen been turned on previously, is there some fluid on the carpet? Such traces can be observed with an infrared (IR) camera that captures images in the IR part of the spectrum. However, it is not well understood if these traces stay visible for a sufficient amount time. Therefore, a first set of experiments was conducted to gain some insight in the visibility degradation of different IR traces over time. The results are discussed in this paper. Furthermore, it will be shown how adding thermal information to the 3D model can improve crime scene understanding.
17. First 3D thermal mapping of an active volcano using an advanced photogrammetric method
Antoine, Raphael; Baratoux, David; Lacogne, Julien; Lopez, Teodolina; Fauchard, Cyrille; Bretar, Frédéric; Arab-Sedze, Mélanie; Staudacher, Thomas; Jacquemoud, Stéphane; Pierrot-Deseilligny, Marc
2014-05-01
Thermal infrared data obtained in the [7-14 microns] spectral range are usually used in many Earth Science disciplines. These studies are exclusively based on the analysis of 2D information. In this case, a quantitative analysis of the surface energy budget remains limited, as it may be difficult to estimate the radiative contribution of the topography, the thermal influence of winds on the surface or potential imprints of subsurface flows on the soil without any precise DEM. The draping of a thermal image on a recent DEM is a common method to obtain a 3D thermal map of a surface. However, this method has many disadvantages i) errors can be significant in the orientation process of the thermal images, due to the lack of tie points between the images and the DEM; ii) the use of a recent DEM implies the use of another remote sensing technique to quantify the topography; iii) finally, the characterization of the evolution of a surface requires the simultaneous acquisition of thermal data and topographic information, which may be expensive in most cases. The stereophotogrammetry method allows to reconstitute the relief of an object from photos taken from different positions. Recently, substantial progress have been realized in the generation of high spatial resolution topographic surfaces using stereophotogrammetry. However, the presence of shadows, homogeneous textures and/or weak contrasts in the visible spectrum (e.g., flowing lavas, uniform lithologies) may prevent from the use of such method, because of the difficulties to find tie points on each image. Such situations are more favorable in the thermal infrared spectrum, as any variation in the thermal properties or geometric orientation of the surfaces may induce temperature contrasts that are detectable with a thermal camera. This system, usually functioning with a array sensor (Focal Plane Array) and an optical device, have geometric characteristics that are similar to digital cameras. Thus, it may be possible
18. Coupled thermal/chemical/mechanical modeling of energetic materials in ALE3D
SciTech Connect
Nichols, A.L.; Couch, R.; Maltby, J.D.; McCallen, R.C.; Otero, I.; Sharp, R.
1996-10-01
We must improve our ability to model the response of energetic ma@ to thmnal stimuli and the processes involved m the energetic response. Traditionally, the analyses of energeuc have mvolved coupled thermal chemical reaction codes. This provides only a reasonable estimate of the dw and location of ensuing rapid reaction. To predict the violence of the reaction, the m cal motion must be included in the wide range of time scales as with the th@ hazard. Ile ALE3D code has been modified to the hazards associated with heaung energetic ma@ in weapons. We have merged the thermal models from TOPAZ3D and the chemistry models &vel@ in Chemical TOPAZ into ALE3D. We have developed and use an impMt time step option to efficiently and accurately compute the hours that the energetic material can take to react. Since on these longer fim scales materials can be expected to have signifimt motion, it is even more important to provide high- ordcr advection for all components, including the chemical species. We will show an example cook-off problem to illustrate these capabilities.
19. The Quantitative Measurement Of Temperature Distribution In 3-D Thermal Field With High-Speed Real-Time Holographic Interferometry
Ji-zong, Wu; Wei-qiao, Fu; Qin, Wu
1989-06-01
The theory of using high-speed real-time holographic interferometry to measure quantitatively 3-D thermal field is discussed in thispaper. An experimental arrangement, and the holographic interference fringes of thermal field formed by the electrAc heating coil wires which were taken by the high-speed camera are given. With CONCEPT 32/2725 computer system and corresponding programms the distribution of 3-D thermal field is calculated and plotted Finally, the problems required to be improved and solved for the method of measuring quantitatively 3-D thermal field are discussed.
20. Classroom Challenge: A 3D Snapshot of Student Learning in Mathematics
ERIC Educational Resources Information Center
Wilder, Sandra
2015-01-01
This article aims to describe a type of formative assessment, MAP Classroom Challenge, which has been introduced in mathematics classrooms in recent years. MAP, or the Mathematics Assessment Project Classroom Challenges (formerly known as Formative Assessment Lessons), are developed by teams of math educators from the Shell Centre for Mathematical…
1. Study of the thermal properties of filaments for 3D printing
Trhlíková, Lucie; Zmeskal, Oldrich; Psencik, Petr; Florian, Pavel
2016-07-01
Various materials are used for 3D printing, most commonly Acrylonitrile butadiene styrene (ABS), Polylactic acid (PLA), Polyethylene (PET) and Polypropylene (PP). These materials differ mainly in their melting point, which significantly influences the properties of the final products. Filaments are melted in the print head during the printing process. The temperature range is from 150 °C to 250 °C depending on the technology used. The optimum temperature for the cooling substrate on which printing is carried out is chosen so as to ensure uniform cooling and deformation. It generally varies between (40 - 100) °C. From the above it is clear that both temperatures can significantly affect the properties of the printed 3D object. It is therefore important to determine the thermal parameters (thermal conductivity, specific heat and thermal diffusivity) of the materials used across the entire range of temperatures. For evaluating the properties of different types of PLA materials, the step transient method was used, which allows determination of all required parameters using a fractal heat transfer model.
2. Modeling thermally driven energetic response of high explosives in ALE3D
SciTech Connect
Aro, C.; McCallen, R.C.; Neely, R.; Nichols, A.L. III; Sharp, R.
1998-10-01
The authors have improved their ability to model the response of energetic materials to thermal stimuli and the processes involved in the energetic response. Traditionally, the analyses of energetic materials have involved coupled thermal transport/chemical reaction codes. This provides only a reasonable estimate of the time and location of ensuing rapid reaction. To predict the violence of the reaction, the mechanical motion must be included in the wide range of time scales associated with the thermal hazard. The ALE3D code has been modified to assess the hazards associated with heating energetic materials in weapons by coupling to thermal transport model and chemistry models. They have developed an implicit time step option to efficiently and accurately compute the hours of heating to reaction of the energetic material. Since, on these longer time scales materials can be expected to have significant motion, it is even more important to provide high-order advection for all components, including the chemical species. They show two examples of coupled thermal/mechanical/chemical models of energetic materials in thermal environments.
3. 3D numerical thermal stress analysis of the high power target for the SLC Positron Source
SciTech Connect
Reuter, E.M.; Hodgson, J.A.
1991-05-01
The volumetrically nonuniform power deposition of the incident 33 GeV electron beam in the SLC Positron Source Target is hypothesized to be the most likely cause target failure. The resultant pulsed temperature distributions are known to generate complicated stress fields with no known closed-form analytical solution. 3D finite element analyses of these temperature distributions and associated thermal stress fields in the new High Power Target are described here. Operational guidelines based on the results of these analyses combined with assumptions made about the fatigue characteristics of the exotic target material are proposed. 6 refs., 4 figs.
4. The Cognitive Apprenticeship Theory for the Teaching of Mathematics in an Online 3D Virtual Environment
ERIC Educational Resources Information Center
2013-01-01
Research spanning two decades shows that there is a continuing development of 3D virtual worlds and investment in such environments for educational purposes. Research stresses the need for these environments to be well-designed and for suitable pedagogies to be implemented in the teaching practice in order for these worlds to be fully effective.…
5. Investigation of thermal degradation with extrusion-based dispensing modules for 3D bioprinting technology.
PubMed
Lee, Hyungseok; Yoo, James J; Kang, Hyun-Wook; Cho, Dong-Woo
2016-02-04
Recently, numerous three-dimensional (3D) bioprinting systems have been introduced for the artificial regeneration of tissues. Among them, the extrusion-based dispensing module is the most widely used because of the processability it gives various biomaterials. The module uses high forces and temperature to dispense materials through a micro-nozzle. Generally, the harsh conditions induce thermal degradation of the material in the dispensing procedure. The thermal degradation affects the properties of the materials, and the change of the properties should be carefully controlled, because it severely affects the regeneration of tissues. Therefore, in this research, the relationship between the dispensing module and the thermal degradation of material was investigated. Extrusion-based dispensing modules can be divided into the syringe type (ST) and filament type (FT) based on working principles. We prepared a poly lactic-co-glycolic acid (PLGA) scaffold with the two methods at various time points. Then, the characteristics of the printed scaffolds were assessed by measuring molecular weight (M w), glass transition temperature (T g), in vitro degradation, compressive modulus, and cytocompatibility. The results showed that the PLGA scaffold with the FT dispensing module maintained its properties regardless of printing time points. In contrast, severe thermal degradation was observed in the scaffold group prepared by the ST dispensing module. Consequentially, it was obvious that the FT dispensing module was more suitable for producing scaffolds without severe thermal degradation.
6. Investigation of thermal degradation with extrusion-based dispensing modules for 3D bioprinting technology.
PubMed
Lee, Hyungseok; Yoo, James J; Kang, Hyun-Wook; Cho, Dong-Woo
2016-03-01
Recently, numerous three-dimensional (3D) bioprinting systems have been introduced for the artificial regeneration of tissues. Among them, the extrusion-based dispensing module is the most widely used because of the processability it gives various biomaterials. The module uses high forces and temperature to dispense materials through a micro-nozzle. Generally, the harsh conditions induce thermal degradation of the material in the dispensing procedure. The thermal degradation affects the properties of the materials, and the change of the properties should be carefully controlled, because it severely affects the regeneration of tissues. Therefore, in this research, the relationship between the dispensing module and the thermal degradation of material was investigated. Extrusion-based dispensing modules can be divided into the syringe type (ST) and filament type (FT) based on working principles. We prepared a poly lactic-co-glycolic acid (PLGA) scaffold with the two methods at various time points. Then, the characteristics of the printed scaffolds were assessed by measuring molecular weight (M w), glass transition temperature (T g), in vitro degradation, compressive modulus, and cytocompatibility. The results showed that the PLGA scaffold with the FT dispensing module maintained its properties regardless of printing time points. In contrast, severe thermal degradation was observed in the scaffold group prepared by the ST dispensing module. Consequentially, it was obvious that the FT dispensing module was more suitable for producing scaffolds without severe thermal degradation. PMID:26844711
7. Thermal analysis of the surrounding anatomy during 3-D MRI-guided transurethral ultrasound prostate therapy
Burtnyk, Mathieu; Chopra, Rajiv; Bronskill, Michael
2010-03-01
Previous numerical simulations have shown that MRI-guided transurethral ultrasound therapy can generate highly accurate volumes of thermal coagulation conforming to 3-D human prostate geometries. The goal of this work is to simulate, quantify and evaluate the thermal impact of these treatments on the rectum, pelvic bone, neurovascular bundles (NVB) and urinary sphincters. This study used twenty 3-D anatomical models of prostate cancer patients and detailed bio-acoustic simulations incorporating an active feedback algorithm which controlled a rotating, planar ultrasound transducer (17-4×3 mm elements, 4.7/9.7 MHz, 10 Wac/cm2). Heating of the adjacent surrounding anatomy was evaluated using thermal tolerances reported in the literature. Heating of the rectum poses the most important safety concern and is influenced largely by the water temperature flowing through an endorectal cooling device; temperatures of 7-37° C are required to limit potential damage to less than 10 mm3 on the outer 1 mm layer of rectum. Significant heating of the pelvic bone was predicted in 30% of the patient models with an ultrasound frequency of 4.7 MHz; setting the frequency to 9.7 MHz when the bone is less than 10 mm away from the prostate reduced heating in all cases below the threshold for irreversible damage. Heating of the NVB was significant in 75% of the patient models in the absence of treatment planning; this proportion was reduced to 5% by using treatment margins of up to 4 mm. To avoid damaging the urinary sphincters, margins from the transducer of 2-4 mm should be used, depending on the transurethral cooling temperature. Simulations show that MRI-guided transurethral therapy can treat the entire prostate accurately. Strategies have been developed which, along with careful treatment planning, can be used to avoid causing thermal injury to the rectum, pelvic bone, NVB and urinary sphincters.
8. Catheter-Based Ultrasound for 3D Control of Thermal Therapy
Diederich, Chris; Chen, Xin; Wootton, Jeffery; Juang, Titania; Nau, Will H.; Kinsey, Adam; Hsu, I.-Chow; Rieke, Viola; Pauly, Kim Butts; Sommer, Graham; Bouley, Donna
2009-04-01
Catheter-based ultrasound applicators have been investigated for delivering hyperthermia and thermal ablation for the treatment of cancer and benign diseases. Technology includes an intrauterine applicator integrated with an HDR ring applicator, interstitial applicators for hyperthermia delivery during brachytherapy, interstitial applicators for tumor ablation, and transurethral devices for conformal prostate ablation. Arrays of multiple sectored tubular transducers have been fabricated for interstitial and intrauterine hyperthermia applicators. High-power interstitial versions have been evaluated for percutaneous implantation with directional or dynamic angular control of thermal ablation. Transurethral applicators include curvilinear transducers with rotational sweeping of narrow heating patterns, and multi-sectored tubular devices capable of dynamic angular control without applicator movement. Performance was evaluated in phantom, excised tissue, in vivo experiments in canine prostate under MR temperature monitoring, clinical hyperthermia, and 3D-biothermal simulations with patient anatomy. Interstitial and intrauterine devices can tailor hyperthermia to large treatment volumes, with multisectored control useful to limit exposure to rectum and bladder. Curvilinear transurethral devices with sequential rotation produce target conforming coagulation zones that can cover either the whole gland or defined focal regions. Multi-sectored transurethral applicators can dynamically control the angular heating profile and target large regions of the prostate without applicator manipulation. High-power interstitial implants with directional devices can be used to effectively ablate defined target regions while avoiding sensitive tissues. MR temperature monitoring can effectively define the extent of thermal damage and provided a means for real-time control of the applicators. In summary, these catheter-based ultrasound devices allow for dynamic control of heating profiles
9. Reconstructing the thermal Sunyaev-Zel'dovich effect in 3D
Pratten, Geraint; Munshi, Dipak
2014-07-01
The thermal Sunyaev-Zel'dovich (tSZ) effect measures the line-of-sight projection of the thermal pressure of free electrons and lacks any redshift information. By cross-correlating the tSZ effect with an external cosmological tracer, we can recover a good fraction of this lost information. Weak lensing (WL) is thought to provide an unbiased probe of the dark Universe, with many WL surveys having sky coverage that overlaps with tSZ surveys. Generalizing the tomographic approach, we advocate the use of the spherical Fourier-Bessel expansion to perform an analysis of the cross-correlation between the projected (2D) tSZ Compton y-parameter maps and 3D WL convergence maps. We use redshift-dependent linear biasing and the halo model as a tool to investigate the tSZ-WL cross-correlations in 3D. We use the Press-Schechter and the Sheth-Tormen mass functions in our calculations, finding that the results are quite sensitive to detailed modelling. We provide detailed analysis of surveys with photometric and spectroscopic redshifts. The signal-to-noise ratio (S/N) of the cross-spectra {C}_{ℓ} (k) for individual 3D modes, defined by the radial and tangential wave numbers (k; ℓ), remains comparable to, but below, unity though optimal binning is expected to improve this. The results presented can be generalized to analyse other cosmic microwave background secondaries, such as the kinetic Sunyaev-Zel'dovich effect.
10. Off- and Along-Axis Slow Spreading Ridge Segment Characters: Insights From 3d Thermal Modeling
Gac, S.; Tisseau, C.; Dyment, J.
2001-12-01
Many observations along the Mid-Atlantic Ridge segments suggest a correlation between surface characters (length, axial morphology) and the thermal state of the segment. Thibaud et al. (1998) classify segments according to their thermal state: "colder" segments shorter than 30 km show a weak magmatic activity, and "hotter" segments as long as 90 km show a robust magmatic activity. The existence of such a correlation suggests that the thermal structure of a slow spreading ridge segment explains most of the surface observations. Here we test the physical coherence of such an integrated thermal model and evaluate it quantitatively. The different kinds of segment would constitute different phases in a segment evolution, the segment evolving progressively from a "colder" to a "hotter" so to a "colder" state. Here we test the consistency of such an evolution scheme. To test these hypotheses we have developed a 3D numerical model for the thermal structure and evolution of a slow spreading ridge segment. The thermal structure is controlled by the geometry and the dimensions of a permanently hot zone, imposed beneath the segment center, where is simulated the adiabatic ascent of magmatic material. To compare the model with the observations several geophysic quantities which depend on the thermal state are simulated: crustal thickness variations along axis, gravity anomalies (reflecting density variations) and earthquake maximum depth (corresponding to the 750° C isotherm depth). The thermal structure of a particular segment is constrained by comparing the simulated quantities to the real ones. Considering realistic magnetization parameters, the magnetic anomalies generated from the same thermal structure and evolution reproduce the observed magnetic anomaly amplitude variations along the segment. The thermal structures accounting for observations are determined for each kind of segment (from "colder" to "hotter"). The evolution of the thermal structure from the "colder" to
11. Mathematical model of testing of pipeline integrity by thermal fields
SciTech Connect
Vaganova, Nataliia
2014-11-18
Thermal fields testing at the ground surface above a pipeline are considered. One method to obtain and investigate an ideal thermal field in different environments is a direct numerical simulation of heat transfer processes taking into account the most important physical factors. In the paper a mathematical model of heat propagation from an underground source is described with accounting of physical factors such as filtration of water in soil and solar radiation. Thermal processes are considered in 3D origin where the heat source is a pipeline with constant temperature and non-uniform isolated shell (with 'damages'). This problem leads to solution of heat diffusivity equation with nonlinear boundary conditions. Approaches to analysis of thermal fields are considered to detect damages.
12. Sign Language for K-8 Mathematics by 3D Interactive Animation
ERIC Educational Resources Information Center
Adamo-Villani, Nicoletta; Doublestein, John; Martin, Zachary
2005-01-01
We present a new highly interactive computer animation tool to increase the mathematical skills of deaf children. We aim at increasing the effectiveness of (hearing) parents in teaching arithmetic to their deaf children, and the opportunity of deaf children to learn arithmetic via interactive media. Using state-of-the-art computer animation…
13. Liquid immersion thermal crosslinking of 3D polymer nanopatterns for direct carbonisation with high structural integrity
PubMed Central
Kang, Da-Young; Kim, Cheolho; Park, Gyurim; Moon, Jun Hyuk
2015-01-01
The direct pyrolytic carbonisation of polymer patterns has attracted interest for its use in obtaining carbon materials. In the case of carbonisation of nanopatterned polymers, the polymer flow and subsequent pattern change may occur in order to relieve their high surface energies. Here, we demonstrated that liquid immersion thermal crosslinking of polymer nanopatterns effectively enhanced the thermal resistance and maintained the structure integrity during the heat treatment. We employed the liquid immersion thermal crosslinking for 3D porous SU8 photoresist nanopatterns and successfully converted them to carbon nanopatterns while maintaining their porous features. The thermal crosslinking reaction and carbonisation of SU8 nanopatterns were characterised. The micro-crystallinity of the SU8-derived carbon nanopatterns was also characterised. The liquid immersion heat treatment can be extended to the carbonisation of various polymer or photoresist nanopatterns and also provide a facile way to control the surface energy of polymer nanopatterns for various purposes, for example, to block copolymer or surfactant self-assemblies. PMID:26677949
14. Liquid immersion thermal crosslinking of 3D polymer nanopatterns for direct carbonisation with high structural integrity
Kang, Da-Young; Kim, Cheolho; Park, Gyurim; Moon, Jun Hyuk
2015-12-01
The direct pyrolytic carbonisation of polymer patterns has attracted interest for its use in obtaining carbon materials. In the case of carbonisation of nanopatterned polymers, the polymer flow and subsequent pattern change may occur in order to relieve their high surface energies. Here, we demonstrated that liquid immersion thermal crosslinking of polymer nanopatterns effectively enhanced the thermal resistance and maintained the structure integrity during the heat treatment. We employed the liquid immersion thermal crosslinking for 3D porous SU8 photoresist nanopatterns and successfully converted them to carbon nanopatterns while maintaining their porous features. The thermal crosslinking reaction and carbonisation of SU8 nanopatterns were characterised. The micro-crystallinity of the SU8-derived carbon nanopatterns was also characterised. The liquid immersion heat treatment can be extended to the carbonisation of various polymer or photoresist nanopatterns and also provide a facile way to control the surface energy of polymer nanopatterns for various purposes, for example, to block copolymer or surfactant self-assemblies.
15. 3D perfused brain phantom for interstitial ultrasound thermal therapy and imaging: design, construction and characterization.
PubMed
Martínez, José M; Jarosz, Boguslaw J
2015-03-01
Thermal therapy has emerged as an independent modality of treating some tumors. In many clinics the hyperthermia, one of the thermal therapy modalities, has been used adjuvant to radio- or chemotherapy to substantially improve the clinical treatment outcomes. In this work, a methodology for building a realistic brain phantom for interstitial ultrasound low dose-rate thermal therapy of the brain is proposed. A 3D brain phantom made of the tissue mimicking material (TMM) had the acoustic and thermal properties in the 20-32 °C range, which is similar to that of a brain at 37 °C. The phantom had 10-11% by mass of bovine gelatin powder dissolved in ethylene glycol. The TMM sonicated at 1 MHz, 1.6 MHz and 2.5 MHz yielded the amplitude attenuation coefficients of 62 ± 1 dB m(-1), 115 ± 4 dB m(-1) and 175 ± 9 dB m(-1), respectively. The density and acoustic speed determination at room temperature (~24 °C) gave 1040 ± 40 kg m(-3) and 1545 ± 44 m s(-1), respectively. The average thermal conductivity was 0.532 W m(-1) K(-1). The T1 and T2 values of the TMM were 207 ± 4 and 36.2 ± 0.4 ms, respectively. We envisage the use of our phantom for treatment planning and for quality assurance in MRI based temperature determination. Our phantom preparation methodology may be readily extended to other thermal therapy technologies.
16. 3D perfused brain phantom for interstitial ultrasound thermal therapy and imaging: design, construction and characterization
Martínez, José M.; Jarosz, Boguslaw J.
2015-03-01
Thermal therapy has emerged as an independent modality of treating some tumors. In many clinics the hyperthermia, one of the thermal therapy modalities, has been used adjuvant to radio- or chemotherapy to substantially improve the clinical treatment outcomes. In this work, a methodology for building a realistic brain phantom for interstitial ultrasound low dose-rate thermal therapy of the brain is proposed. A 3D brain phantom made of the tissue mimicking material (TMM) had the acoustic and thermal properties in the 20-32 °C range, which is similar to that of a brain at 37 °C. The phantom had 10-11% by mass of bovine gelatin powder dissolved in ethylene glycol. The TMM sonicated at 1 MHz, 1.6 MHz and 2.5 MHz yielded the amplitude attenuation coefficients of 62 ± 1 dB m-1, 115 ± 4 dB m-1 and 175 ± 9 dB m-1, respectively. The density and acoustic speed determination at room temperature (~24 °C) gave 1040 ± 40 kg m-3 and 1545 ± 44 m s-1, respectively. The average thermal conductivity was 0.532 W m-1 K-1. The T1 and T2 values of the TMM were 207 ± 4 and 36.2 ± 0.4 ms, respectively. We envisage the use of our phantom for treatment planning and for quality assurance in MRI based temperature determination. Our phantom preparation methodology may be readily extended to other thermal therapy technologies.
17. 3D neutronic codes coupled with thermal-hydraulic system codes for PWR, and BWR and VVER reactors
SciTech Connect
Langenbuch, S.; Velkov, K.; Lizorkin, M.
1997-07-01
This paper describes the objectives of code development for coupling 3D neutronics codes with thermal-hydraulic system codes. The present status of coupling ATHLET with three 3D neutronics codes for VVER- and LWR-reactors is presented. After describing the basic features of the 3D neutronic codes BIPR-8 from Kurchatov-Institute, DYN3D from Research Center Rossendorf and QUABOX/CUBBOX from GRS, first applications of coupled codes for different transient and accident scenarios are presented. The need of further investigations is discussed.
18. Zig-Zag Thermal-Chemical 3-D Instabilities in the Mantle Wedge: Numerical Study
Zhu, G.; Gerya, T. V.; Arcay, D.; Yuen, D. A.
2008-12-01
To understand the plume initiation and propagation it is important to understand whether small-scale convection is occurring under the back-arc in the Low Viscosity Wedge(LVW) and its implication on the island-arc volcanism. Honda et al. [Honda and Saito, 2003; Honda, et al., 2007]) already deployed small- scale convection in the Low Viscosity Wedge (LVW) above a subducting slab with kinematically imposed velocity boundary condition. They have suggested that a roll (finger)-like pattern of hot and cold anomalies emerges in the mantle wedge above the subducting slab. Here, we perform three-dimensional coupled petrological-thermomechanical numerical simulations of intraoceanic one-sided subduction with spontaneously bending retreating slab characterized by weak hydrated upper interface by using multigrid approach combined with characteristics-based marker-in-cell method with conservative finite difference schemes[Gerya and Yuen, 2003a], to investigate the 3D instabilities above the slab and lateral variation along the arc. Our results show that water released from subducting slab through dehydration reactions may lower the viscosity of the mantle. It allows the existence of wave-like small-scale convection in the LVW, which is shown as roll-like structure in 2D petrological-thermomechanical numerical experiments [Gorczyk et al., 2006] using in-situ rock properties computed on the basis of Gibbs free energy minimization. However, in our 3D cases, the rolls aligning with the arc mainly occur earlier , while zig-zag small-scale thermal-chemical instabilities may episodically form above the slab at later stages, which is different from the aligning finger-like pattern in purely thermal models (Honda et al,2003;2007). Also in contrast to thermal convection chemically buoyant hydrated plumes rising from the slab in our models are actually colder then the mantle wedge [Gerya and Yuen 2003b] which also strongly modify both the convection pattern and the seismic structure in
19. 3D coexisting modes of thermal convection in the faulted Lower Yarmouk Gorge
Magri, Fabien; Inbar, Nimrod; Möller, Peter; Raggad, Marwan; Rödiger, Tino; Rosenthal, Eliyahu; Siebert, Christian
2016-04-01
Numerical investigations of 3D modes of large-scale convection in faulted aquifers are presented with the aim to infer possible transport mechanisms supporting the formation of thermal springs in the Lower Yarmouk Gorge (LYG), at the border between Israel and Jordan. The transient finite elements models are based on a geological model of the LYG that introduces more realistic structural features of the basin, compared to previous existing models of the area (Magri et al., submitted). The sensitivity analysis of the fault permeability showed that faults cross-cutting the main regional flow direction allow groundwater to be driven laterally by convective forces within the fault planes. Therein thermal waters can either discharge along the fault traces or exit the fault through adjacent permeable aquifers. The location of springs can migrate with time, is not strictly constrained to the damage zones and reflects the interplay between the wavelength of the multicellular regime in the fault zone and the regional flow toward discharge areas in the lowlands. The results presented here suggest that in the LYG case, crossing flow paths result from the coexistence of fault convection, that can develop for example along NE-SW oriented faults within the Gorge, and additional flow fields that can be induced either by topography N-S gradients, e.g. perpendicular to the major axe of the Gorge, or by local thermal convection in permeable aquifers below Eocene aquiclude. The sensitivity analysis is consistent with the analytical solutions based on viscous-dependent Rayleigh theory. It indicates that in the LYG coexisting transport processes likely occur at fault hydraulic conductivity ranging between 2.3e-7 m/s and 9.3e- 7 m/s (i.e. 7 m/yr and 30 m/yr). The LYG numerical example and the associated Rayleigh analysis can be applied to study the onset of thermal convection and resulting flow patterns of any fractured hydrothermal basin. References Magri F, Möller S, Inbar N, M
20. The mantle wedge's transient 3-D flow regime and thermal structure
Davies, D. R.; Le Voci, G.; Goes, S.; Kramer, S. C.; Wilson, C. R.
2016-01-01
Arc volcanism, volatile cycling, mineralization, and continental crust formation are likely regulated by the mantle wedge's flow regime and thermal structure. Wedge flow is often assumed to follow a regular corner-flow pattern. However, studies that incorporate a hydrated rheology and thermal buoyancy predict internal small-scale-convection (SSC). Here, we systematically explore mantle-wedge dynamics in 3-D simulations. We find that longitudinal "Richter-rolls" of SSC (with trench-perpendicular axes) commonly occur if wedge hydration reduces viscosities to Pa s, although transient transverse rolls (with trench-parallel axes) can dominate at viscosities of Pa s. Rolls below the arc and back arc differ. Subarc rolls have similar trench-parallel and trench-perpendicular dimensions of 100-150 km and evolve on a 1-5 Myr time-scale. Subback-arc instabilities, on the other hand, coalesce into elongated sheets, usually with a preferential trench-perpendicular alignment, display a wavelength of 150-400 km and vary on a 5-10 Myr time scale. The modulating influence of subback-arc ridges on the subarc system increases with stronger wedge hydration, higher subduction velocity, and thicker upper plates. We find that trench-parallel averages of wedge velocities and temperature are consistent with those predicted in 2-D models. However, lithospheric thinning through SSC is somewhat enhanced in 3-D, thus expanding hydrous melting regions and shifting dehydration boundaries. Subarc Richter-rolls generate time-dependent trench-parallel temperature variations of up to K, which exceed the transient 50-100 K variations predicted in 2-D and may contribute to arc-volcano spacing and the variable seismic velocity structures imaged beneath some arcs.
1. Towards a More Effective Use of 3D-Graphics in Mathematics Education--Utilisation of KETpic to Insert Figures into LATEX Documents
ERIC Educational Resources Information Center
Kitahara, Kiyoshi; Abe, Takayuki; Kaneko, Masataka; Yamashita, Satoshi; Takato, Setsuo
2010-01-01
Computer Algebra Systems (CAS) are equipped with rich facilities to show graphics, so the use of CAS to show 3D-graphics on screen is a popular tool for mathematics education. However, showing 3D-graphics in mass printed materials is a different story, since the clarity and preciseness of figures tend to be lost. To fill this gap, we developed…
2. Thermal and Residual Excited-State Population in a 3D Transmon Qubit.
PubMed
Jin, X Y; Kamal, A; Sears, A P; Gudmundsen, T; Hover, D; Miloshi, J; Slattery, R; Yan, F; Yoder, J; Orlando, T P; Gustavsson, S; Oliver, W D
2015-06-19
Remarkable advancements in coherence and control fidelity have been achieved in recent years with cryogenic solid-state qubits. Nonetheless, thermalizing such devices to their milliKelvin environments has remained a long-standing fundamental and technical challenge. In this context, we present a systematic study of the first-excited-state population in a 3D transmon superconducting qubit mounted in a dilution refrigerator with a variable temperature. Using a modified version of the protocol developed by Geerlings et al., we observe the excited-state population to be consistent with a Maxwell-Boltzmann distribution, i.e., a qubit in thermal equilibrium with the refrigerator, over the temperature range 35-150 mK. Below 35 mK, the excited-state population saturates at approximately 0.1%. We verified this result using a flux qubit with ten times stronger coupling to its readout resonator. We conclude that these qubits have effective temperature T(eff)=35 mK. Assuming T(eff) is due solely to hot quasiparticles, the inferred qubit lifetime is 108 μs and in plausible agreement with the measured 80 μs.
3. Thermal and Residual Excited-State Population in a 3D Transmon Qubit
Jin, X. Y.; Kamal, A.; Sears, A. P.; Gudmundsen, T.; Hover, D.; Miloshi, J.; Slattery, R.; Yan, F.; Yoder, J.; Orlando, T. P.; Gustavsson, S.; Oliver, W. D.
2015-06-01
Remarkable advancements in coherence and control fidelity have been achieved in recent years with cryogenic solid-state qubits. Nonetheless, thermalizing such devices to their milliKelvin environments has remained a long-standing fundamental and technical challenge. In this context, we present a systematic study of the first-excited-state population in a 3D transmon superconducting qubit mounted in a dilution refrigerator with a variable temperature. Using a modified version of the protocol developed by Geerlings et al., we observe the excited-state population to be consistent with a Maxwell-Boltzmann distribution, i.e., a qubit in thermal equilibrium with the refrigerator, over the temperature range 35-150 mK. Below 35 mK, the excited-state population saturates at approximately 0.1%. We verified this result using a flux qubit with ten times stronger coupling to its readout resonator. We conclude that these qubits have effective temperature Teff=35 mK . Assuming Teff is due solely to hot quasiparticles, the inferred qubit lifetime is 108 μ s and in plausible agreement with the measured 80 μ s .
4. Closed-loop high-speed 3D thermal probe nanolithography
Knoll, A. W.; Zientek, M.; Cheong, L. L.; Rawlings, C.; Paul, P.; Holzner, F.; Hedrick, J. L.; Coady, D. J.; Allen, R.; Dürig, U.
2014-03-01
Thermal Scanning Probe Lithography (tSPL) is an AFM based patterning technique, which uses heated tips to locally evaporate organic resists such as molecular glasses [1] or thermally sensitive polymers.[2][3] Organic resists offer the versatility of the lithography process known from the CMOS environment and simultaneously ensure a highly stable and low wear tip-sample contact due to the soft nature of the resists. Patterning quality is excellent up to a resolution of sub 15 nm,[1] at linear speeds of up to 20 mm/s and pixel rates of up to 500 kHz.[4] The patterning depth is proportional to the applied force which allows for the creation of 3-D profiles in a single patterning run.[2] In addition, non-destructive imaging can be done at pixel rates of more than 500 kHz.[4] If the thermal stimulus for writing the pattern is switched off the same tip can be used to record the written topography with Angstrom depth resolution. We utilize this unique feature of SPL to implement an efficient control system for reliable patterning at high speed and high resolution. We combine the writing and imaging process in a single raster scan of the surface. In this closed loop lithography (CLL) approach, we use the acquired data to optimize the writing parameters on the fly. Excellent control is in particular important for an accurate reproduction of complex 3D patterns. These novel patterning capabilities are equally important for a high quality transfer of two-dimensional patterns into the underlying substrate. We utilize an only 3-4 nm thick SiOx hardmask to amplify the 8±0.5 nm deep patterns created by tSPL into a 50 nm thick transfer polymer. The structures in the transfer polymer can be used to create metallic lines by a lift-off process or to further process the pattern into the substrate. Here we demonstrate the fabrication of 27 nm wide lines and trenches 60 nm deep into the Silicon substrate.[5] In addition, the combined read and write approach ensures that the lateral
5. Classification of mathematics deficiency using shape and scale analysis of 3D brain structures
Kurtek, Sebastian; Klassen, Eric; Gore, John C.; Ding, Zhaohua; Srivastava, Anuj
2011-03-01
We investigate the use of a recent technique for shape analysis of brain substructures in identifying learning disabilities in third-grade children. This Riemannian technique provides a quantification of differences in shapes of parameterized surfaces, using a distance that is invariant to rigid motions and re-parameterizations. Additionally, it provides an optimal registration across surfaces for improved matching and comparisons. We utilize an efficient gradient based method to obtain the optimal re-parameterizations of surfaces. In this study we consider 20 different substructures in the human brain and correlate the differences in their shapes with abnormalities manifested in deficiency of mathematical skills in 106 subjects. The selection of these structures is motivated in part by the past links between their shapes and cognitive skills, albeit in broader contexts. We have studied the use of both individual substructures and multiple structures jointly for disease classification. Using a leave-one-out nearest neighbor classifier, we obtained a 62.3% classification rate based on the shape of the left hippocampus. The use of multiple structures resulted in an improved classification rate of 71.4%.
6. New 3D thermal evolution model for icy bodies application to trans-Neptunian objects
Guilbert-Lepoutre, A.; Lasue, J.; Federico, C.; Coradini, A.; Orosei, R.; Rosenberg, E. D.
2011-05-01
Context. Thermal evolution models have been developed over the years to investigate the evolution of thermal properties based on the transfer of heat fluxes or transport of gas through a porous matrix, among others. Applications of such models to trans-Neptunian objects (TNOs) and Centaurs has shown that these bodies could be strongly differentiated from the point of view of chemistry (i.e. loss of most volatile ices), as well as from physics (e.g. melting of water ice), resulting in stratified internal structures with differentiated cores and potential pristine material close to the surface. In this context, some observational results, such as the detection of crystalline water ice or volatiles, remain puzzling. Aims: In this paper, we would like to present a new fully three-dimensional thermal evolution model. With this model, we aim to improve determination of the temperature distribution inside icy bodies such as TNOs by accounting for lateral heat fluxes, which have been proven to be important for accurate simulations. We also would like to be able to account for heterogeneous boundary conditions at the surface through various albedo properties, for example, that might induce different local temperature distributions. Methods: In a departure from published modeling approaches, the heat diffusion problem and its boundary conditions are represented in terms of real spherical harmonics, increasing the numerical efficiency by roughly an order of magnitude. We then compare this new model and another 3D model recently published to illustrate the advantages and limits of the new model. We try to put some constraints on the presence of crystalline water ice at the surface of TNOs. Results: The results obtained with this new model are in excellent agreement with results obtained by different groups with various models. Small TNOs could remain primitive unless they are formed quickly (less than 2 Myr) or are debris from the disruption of larger bodies. We find that, for
7. Revitalizing the Space Shuttle's Thermal Protection System with Reverse Engineering and 3D Vision Technology
NASA Technical Reports Server (NTRS)
2008-01-01
The Space Shuttle is protected by a Thermal Protection System (TPS) made of tens of thousands of individually shaped heat protection tile. With every flight, tiles are damaged on take-off and return to earth. After each mission, the heat tiles must be fixed or replaced depending on the level of damage. As part of the return to flight mission, the TPS requirements are more stringent, leading to a significant increase in heat tile replacements. The replacement operation requires scanning tile cavities, and in some cases the actual tiles. The 3D scan data is used to reverse engineer each tile into a precise CAD model, which in turn, is exported to a CAM system for the manufacture of the heat protection tile. Scanning is performed while other activities are going on in the shuttle processing facility. Many technicians work simultaneously on the space shuttle structure, which results in structural movements and vibrations. This paper will cover a portable, ultra-fast data acquisition approach used to scan surfaces in this unstable environment.
8. Interface requirements to couple thermal-hydraulic codes to 3D neutronic codes
SciTech Connect
Langenbuch, S.; Austregesilo, H.; Velkov, K.
1997-07-01
The present situation of thermalhydraulics codes and 3D neutronics codes is briefly described and general considerations for coupling of these codes are discussed. Two different basic approaches of coupling are identified and their relative advantages and disadvantages are discussed. The implementation of the coupling for 3D neutronics codes in the system ATHLET is presented. Meanwhile, this interface is used for coupling three different 3D neutronics codes.
9. Development of a 3D patient-specific planning platform for interstitial and transurethral ultrasound thermal therapy
Prakash, Punit; Diederich, Chris J.
2010-03-01
Interstitial and transurethral catheter-based ultrasound devices are under development for treatment of prostate cancer and BPH, uterine fibroids, liver tumors and other soft tissue disease. Accurate 3D thermal modeling is essential for designing site-specific applicators, exploring treatment delivery strategies, and integration of patient-specific treatment planning of thermal ablations. We are developing a comprehensive 3D modeling and treatment planning platform for ultrasound ablation of tissue using catheter-based applicators. We explored the applicability of assessing thermal effects in tissue using critical temperature, thermal dose and Arrhenius thermal damage thresholds and performed a comparative analysis of dynamic tissue properties critical to accurate modeling. We used the model to assess the feasibility of automatic feedback control with MR thermometry, and demonstrated the utility of the modeling platform for 3D patient-specific treatment planning. We have identified critical temperature, thermal dose and thermal damage thresholds for assessing treatment endpoint. Dynamic changes in tissue attenuation/absorption and perfusion must be included for accurate prediction of temperature profiles and extents of the ablation zone. Lastly, we demonstrated use of the modeling platform for patient-specific treatment planning.
10. 3D thermal history and maturity modelling of the Levant Basin and Margin
Daher, Samer Bou; Ducros, Mathieu; Michel, Pauline; Nader, Fadi H.; Littke, Ralf
2015-04-01
The gas discoveries recorded in the Levant Basin in the last decade have redirected the industrial and academic communities' interest to this frontier basin and its surroundings. The reported gas in Miocene reservoirs has been assumed to be derived from biogenic sources, although little data has been published so far. The thickness of the sedimentary column and the presence of direct hydrocarbon indicators (DHI) observed in the seismic data suggest the presence of promising prospective thermogenic petroleum systems in deeper intervals in the Levant Basin and along its Margin. In this study we present a large scale 3D thermal history and maturity model of the Levant Basin and Margin, integrating all available calibration data, source rock information collected from onshore Lebanon, and published data. In the first part we will present the main input and assumptions that were made in terms of thicknesses, lithologies, and boundary conditions. In the second part we will discuss the analysed source rocks, their petroleum generation potential and their kinetics. In the third part we will present modelling results including depth maps for key isotherms in addition to transformation ratio and vitrinite reflectance maps for proven and speculative source rocks at different time steps. This will provide a comprehensive assessment of the potential thermogenic petroleum systems in the study area, and allow us to illustrate and discuss the differences between the basinal, marginal, and onshore part of the study area as well as the potential of the northern vis a vis the southern offshore Levant Basin. This model will also allow us to analyse the sensitivity of the system to the various poorly constrained parameters in frontier basins (e.g. crustal thickness, rifting phases, lithologies) and thus identify the most critical data to be collected for future exploration and de-risking strategies.
11. Numerical Analysis of Thermal Remediation in 3D Field-Scale Fractured Geologic Media.
PubMed
Chen, Fei; Falta, Ronald W; Murdoch, Lawrence C
2015-01-01
Thermal methods are promising for remediating fractured geologic media contaminated with volatile organic compounds, and the success of this process depends on the coupled heat transfer, multiphase flow, and thermodynamics. This study analyzed field-scale removal of trichloroethylene (TCE) and heat transfer behavior in boiling fractured geologic media using the multiple interacting continua method. This method can resolve local gradients in the matrix and is less computationally demanding than alternative methods like discrete fracture-matrix models. A 2D axisymmetric model was used to simulate a single element of symmetry in a repeated pattern of extraction wells inside a large heated zone and evaluate effects of parameter sensitivity on contaminant recovery. The results showed that the removal of TCE increased with matrix permeability, and the removal rate was more sensitive to matrix permeability than any other parameter. Increasing fracture density promoted TCE removal, especially when the matrix permeability was low (e.g., <10(-17) m(2)). A 3D model was used to simulate an entire treatment zone and the surrounding groundwater in fractured material, with the interaction between them being considered. Boiling was initiated in the center of the upper part of the heated region and expanded toward the boundaries. This boiling process resulted in a large increase in the TCE removal rate and spread of TCE to the vadose zone and the peripheries of the heated zone. The incorporation of extraction wells helped control the contaminant from migrating to far regions. After 22 d, more than 99.3% of TCE mass was recovered in the simulation. PMID:25040727
12. Numerical Analysis of Thermal Remediation in 3D Field-Scale Fractured Geologic Media.
PubMed
Chen, Fei; Falta, Ronald W; Murdoch, Lawrence C
2015-01-01
Thermal methods are promising for remediating fractured geologic media contaminated with volatile organic compounds, and the success of this process depends on the coupled heat transfer, multiphase flow, and thermodynamics. This study analyzed field-scale removal of trichloroethylene (TCE) and heat transfer behavior in boiling fractured geologic media using the multiple interacting continua method. This method can resolve local gradients in the matrix and is less computationally demanding than alternative methods like discrete fracture-matrix models. A 2D axisymmetric model was used to simulate a single element of symmetry in a repeated pattern of extraction wells inside a large heated zone and evaluate effects of parameter sensitivity on contaminant recovery. The results showed that the removal of TCE increased with matrix permeability, and the removal rate was more sensitive to matrix permeability than any other parameter. Increasing fracture density promoted TCE removal, especially when the matrix permeability was low (e.g., <10(-17) m(2)). A 3D model was used to simulate an entire treatment zone and the surrounding groundwater in fractured material, with the interaction between them being considered. Boiling was initiated in the center of the upper part of the heated region and expanded toward the boundaries. This boiling process resulted in a large increase in the TCE removal rate and spread of TCE to the vadose zone and the peripheries of the heated zone. The incorporation of extraction wells helped control the contaminant from migrating to far regions. After 22 d, more than 99.3% of TCE mass was recovered in the simulation.
13. 3D networked graphene-ferromagnetic hybrids for fast shape memory polymers with enhanced mechanical stiffness and thermal conductivity.
PubMed
Lee, Sang-Heon; Jung, Jung-Hwan; Oh, Il-Kwon
2014-10-15
A novel 3D networked graphene-ferromagnetic hybrid can be easily fabricated using one-step microwave irradiation. By incorporating this hybrid material into shape memory polymers, the synergistic effects of fast speed and the enhancement of thermal conductivity and mechanical stiffness can be achieved. This can be broadly applicable to designing magneto-responsive shape memory polymers for multifunction applications.
14. The Intercomparison of 3D Radiation Codes (I3RC): Showcasing Mathematical and Computational Physics in a Critical Atmospheric Application
Davis, A. B.; Cahalan, R. F.
2001-05-01
The Intercomparison of 3D Radiation Codes (I3RC) is an on-going initiative involving an international group of over 30 researchers engaged in the numerical modeling of three-dimensional radiative transfer as applied to clouds. Because of their strong variability and extreme opacity, clouds are indeed a major source of uncertainty in the Earth's local radiation budget (at GCM grid scales). Also 3D effects (at satellite pixel scales) invalidate the standard plane-parallel assumption made in the routine of cloud-property remote sensing at NASA and NOAA. Accordingly, the test-cases used in I3RC are based on inputs and outputs which relate to cloud effects in atmospheric heating rates and in real-world remote sensing geometries. The main objectives of I3RC are to (1) enable participants to improve their models, (2) publish results as a community, (3) archive source code, and (4) educate. We will survey the status of I3RC and its plans for the near future with a special emphasis on the mathematical models and computational approaches. We will also describe some of the prime applications of I3RC's efforts in climate models, cloud-resolving models, and remote-sensing observations of clouds, or that of the surface in their presence. In all these application areas, computational efficiency is the main concern and not accuracy. One of I3RC's main goals is to document the performance of as wide a variety as possible of three-dimensional radiative transfer models for a small but representative number of cases.'' However, it is dominated by modelers working at the level of linear transport theory (i.e., they solve the radiative transfer equation) and an overwhelming majority of these participants use slow-but-robust Monte Carlo techniques. This means that only a small portion of the efficiency vs. accuracy vs. flexibility domain is currently populated by I3RC participants. To balance this natural clustering the present authors have organized a systematic outreach towards
15. A mathematical method for the 3D analysis of rotating deformable systems applied on lumen-forming MDCK cell aggregates.
PubMed
Marmaras, Anastasios; Berge, Ulrich; Ferrari, Aldo; Kurtcuoglu, Vartan; Poulikakos, Dimos; Kroschewski, Ruth
2010-04-01
Cell motility contributes to the formation of organs and tissues, into which multiple cells self-organize. However such mammalian cellular motilities are not characterized in a quantitative manner and the systemic consequences are thus unknown. A mathematical tool to decipher cell motility, accounting for changes in cell shape, within a three-dimensional (3D) cell system was missing. We report here such a tool, usable on segmented images reporting the outline of clusters (cells) and allowing the time-resolved 3D analysis of circular motility of these as parts of a system (cell aggregate). Our method can analyze circular motility in sub-cellular, cellular, multi-cellular, and also non-cellular systems for which time-resolved segmented cluster outlines are available. To exemplify, we characterized the circular motility of lumen-initiating MDCK cell aggregates, embedded in extracellular matrix. We show that the organization of the major surrounding matrix fibers was not significantly affected during this cohort rotation. Using our developed tool, we discovered two classes of circular motion, rotation and random walk, organized in three behavior patterns during lumen initiation. As rotational movements were more rapid than random walk and as both could continue during lumen initiation, we conclude that neither the class nor the rate of motion regulates lumen initiation. We thus reveal a high degree of plasticity during a developmentally critical cell polarization step, indicating that lumen initiation is a robust process. However, motility rates decreased with increasing cell number, previously shown to correlate with epithelial polarization, suggesting that migratory polarization is converted into epithelial polarization during aggregate development. PMID:20183868
16. Ice-Templated Assembly Strategy to Construct 3D Boron Nitride Nanosheet Networks in Polymer Composites for Thermal Conductivity Improvement.
PubMed
Zeng, Xiaoliang; Yao, Yimin; Gong, Zhengyu; Wang, Fangfang; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping
2015-12-01
Owing to the growing heat removal issue of modern electronic devices, polymer composites with high thermal conductivity have drawn much attention in the past few years. However, a traditional method to enhance the thermal conductivity of the polymers by addition of inorganic fillers usually creates composite with not only limited thermal conductivity but also other detrimental effects due to large amount of fillers required. Here, novel polymer composites are reported by first constructing 3D boron nitride nanosheets (3D-BNNS) network using ice-templated approach and then infiltrating them with epoxy matrix. The obtained polymer composites exhibit a high thermal conductivity (2.85 W m(-1) K(-1)), a low thermal expansion coefficient (24-32 ppm K(-1)), and an increased glass transition temperature (T(g)) at relatively low BNNSs loading (9.29 vol%). These results demonstrate that this approach opens a new avenue for design and preparation of polymer composites with high thermal conductivity. The polymer composites are potentially useful in advanced electronic packaging techniques, namely, thermal interface materials, underfill materials, molding compounds, and organic substrates. PMID:26479262
17. Ice-Templated Assembly Strategy to Construct 3D Boron Nitride Nanosheet Networks in Polymer Composites for Thermal Conductivity Improvement.
PubMed
Zeng, Xiaoliang; Yao, Yimin; Gong, Zhengyu; Wang, Fangfang; Sun, Rong; Xu, Jianbin; Wong, Ching-Ping
2015-12-01
Owing to the growing heat removal issue of modern electronic devices, polymer composites with high thermal conductivity have drawn much attention in the past few years. However, a traditional method to enhance the thermal conductivity of the polymers by addition of inorganic fillers usually creates composite with not only limited thermal conductivity but also other detrimental effects due to large amount of fillers required. Here, novel polymer composites are reported by first constructing 3D boron nitride nanosheets (3D-BNNS) network using ice-templated approach and then infiltrating them with epoxy matrix. The obtained polymer composites exhibit a high thermal conductivity (2.85 W m(-1) K(-1)), a low thermal expansion coefficient (24-32 ppm K(-1)), and an increased glass transition temperature (T(g)) at relatively low BNNSs loading (9.29 vol%). These results demonstrate that this approach opens a new avenue for design and preparation of polymer composites with high thermal conductivity. The polymer composites are potentially useful in advanced electronic packaging techniques, namely, thermal interface materials, underfill materials, molding compounds, and organic substrates.
18. Combination of thermal extrusion printing and ultrafast laser fabrication for the manufacturing of 3D composite scaffolds
Balčiūnas, Evaldas; Lukoševičius, Laurynas; Mackevičiūtė, Dovilė; Rekštytė, Sima; Rutkūnas, Vygandas; Paipulas, Domas; Stankevičiūtė, Karolina; Baltriukienė, Daiva; Bukelskienė, Virginija; Piskarskas, Algis P.; Malinauskas, Mangirdas
2014-03-01
We present a novel approach to manufacturing 3D microstructured composite scaffolds for tissue engineering applications. A thermal extrusion 3D printer - a simple, low-cost tabletop device enabling rapid materialization of CAD models in plastics - was used to produce cm-scale microporous scaffolds out of polylactic acid (PLA). The fabricated objects were subsequently immersed in a photosensitive monomer solution and direct laser writing technique (DLW) was used to refine its inner structure by fabricating a fine mesh inside the previously produced scaffold. In addition, a composite material structure out of four different materials fabricated via DLW is presented. This technique, empowered by ultrafast lasers allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. A composite scaffold made of distinct materials and periodicities is acquired after the development process used to wash out non-linked monomers. Another way to modify the 3D printed PLA surfaces was also demonstrated - ablation with femtosecond laser beam. Structure geometry on macro- to micro- scales could be finely tuned by combining these fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. To our best knowledge, this is the first experimental demonstration showing the creation of composite 3D scaffolds using convenient 3D printing combined with DLW. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro-featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of tissue engineering, as well as in microelectromechanical systems, microfluidics, microoptics and others.
19. Evaluation of Methods for Coregistration and Fusion of Rpas-Based 3d Point Clouds and Thermal Infrared Images
Hoegner, L.; Tuttas, S.; Xu, Y.; Eder, K.; Stilla, U.
2016-06-01
This paper discusses the automatic coregistration and fusion of 3d point clouds generated from aerial image sequences and corresponding thermal infrared (TIR) images. Both RGB and TIR images have been taken from a RPAS platform with a predefined flight path where every RGB image has a corresponding TIR image taken from the same position and with the same orientation with respect to the accuracy of the RPAS system and the inertial measurement unit. To remove remaining differences in the exterior orientation, different strategies for coregistering RGB and TIR images are discussed: (i) coregistration based on 2D line segments for every single TIR image and the corresponding RGB image. This method implies a mainly planar scene to avoid mismatches; (ii) coregistration of both the dense 3D point clouds from RGB images and from TIR images by coregistering 2D image projections of both point clouds; (iii) coregistration based on 2D line segments in every single TIR image and 3D line segments extracted from intersections of planes fitted in the segmented dense 3D point cloud; (iv) coregistration of both the dense 3D point clouds from RGB images and from TIR images using both ICP and an adapted version based on corresponding segmented planes; (v) coregistration of both image sets based on point features. The quality is measured by comparing the differences of the back projection of homologous points in both corrected RGB and TIR images.
20. An Examination of the Effects of Collaborative Scientific Visualization via Model-Based Reasoning on Science, Technology, Engineering, and Mathematics (STEM) Learning within an Immersive 3D World
ERIC Educational Resources Information Center
Soleimani, Ali
2013-01-01
Immersive 3D worlds can be designed to effectively engage students in peer-to-peer collaborative learning activities, supported by scientific visualization, to help with understanding complex concepts associated with learning science, technology, engineering, and mathematics (STEM). Previous research studies have shown STEM learning benefits…
1. Automotive Underhood Thermal Management Analysis Using 3-D Coupled Thermal-Hydrodynamic Computer Models: Thermal Radiation Modeling
SciTech Connect
Pannala, S; D'Azevedo, E; Zacharia, T
2002-02-26
2. Thermally induced apoptosis, necrosis, and heat shock protein expression in 3D culture.
PubMed
Song, Alfred S; Najjar, Amer M; Diller, Kenneth R
2014-07-01
This study was conducted to compare the heat shock responses of cells grown in 2D and 3D culture environments as indicated by the level of heat shock protein 70 expression and the incidence of apoptosis and necrosis of prostate cancer cell lines in response to graded hyperthermia. PC3 cells were stably transduced with a dual reporter system composed of two tandem expression cassettes-a conditional heat shock protein promoter driving the expression of green fluorescent protein (HSPp-GFP) and a cytomegalovirus (CMV) promoter controlling the constitutive expression of a "beacon" red fluorescent protein (CMVp-RFP). Two-dimensional and three-dimensional cultures of PC3 prostate cancer cells were grown in 96-well plates for evaluation of their time-dependent response to supraphysiological temperature. To induce controlled hyperthermia, culture plates were placed on a flat copper surface of a circulating water manifold that maintained the specimens within ±0.1°C of a target temperature. Hyperthermia protocols included various combinations of temperature, ranging from 37°C to 57°C, and exposure times of up to 2 h. The majority of protocols were focused on temperature and time permutations, where the response gradient was greatest. Post-treatment analysis by flow cytometry analysis was used to measure the incidences of apoptosis (annexin V-FITC stain), necrosis (propidium iodide (PI) stain), and HSP70 transcription (GFP expression). Cells grown in 3D compared with 2D culture showed reduced incidence of apoptosis and necrosis and a higher level of HSP70 expression in response to heat shock at the temperatures tested. Cells responded differently to hyperthermia when grown in 2D and 3D cultures. Three-dimensional culture appears to enhance survival plausibly by activating protective processes related to enhanced-HSP70 expression. These differences highlight the importance of selecting physiologically relevant 3D models in assessing cellular responses to hyperthermia in
3. Searching for Thermal Anomalies on Icy Satellites: Step 1- Validation of the Three Dimensional Volatile-Transport (VT3D)
Simmons, Gary G.; Howett, Carly J. A.; Young, Leslie A.; Spencer, John R.
2015-11-01
In the last few decades, thermal data from the Galileo and Cassini spacecraft have detected various anomalies on Jovian and Saturnian satellites, including the thermally anomalous “PacMan” regions on Mimas and Tethys and the Pwyll anomaly on Europa (Howett et al. 2011, Howett et al. 2012, Spencer et al. 1999). Yet, the peculiarities of some of these anomalies, like the weak detection of the “PacMan” anomalies on Rhea and Dione and the low thermal inertia values of the widespread anomalies on equatorial Europa, are subjects for on-going research (Howett et al. 2014, Rathbun et al. 2010). Further, analysis and review of all the data both Galileo and Cassini took of these worlds will provide information of the thermal inertia and albedos of their surfaces, perhaps highlighting potential targets of interest for future Jovian and Saturnian system missions. Many previous works have used a thermophysical model for airless planets developed by Spencer (1990). However, the Three Dimensional Volatile-Transport (VT3D) model proposed by Young (2012) is able to predict surface temperatures in significantly faster computation time, incorporating seasonal and diurnal insolation variations. This work is the first step in an ongoing investigation, which will use VT3D’s capabilities to reanalyze Galileo and Cassini data. VT3D, which has already been used to analyze volatile transport on Pluto, is validated by comparing its results to that of the Spencer thermal model. We will also present our initial results using VT3D to reanalyze the thermophysical properties of the PacMan anomaly previous discovered on Mimas by Howett et al. (2011), using temperature constraints of diurnal data from Cassini/CIRS. VT3D is expected to be an efficient tool in identifying new thermal anomalies in future Saturnian and Jovian missions.Bibliography:C.J.A. Howett et al. (2011), Icarus 216, 221.C.J.A. Howett et al. (2012), Icarus 221, 1084.C.J.A. Howett et al. (2014), Icarus 241, 239.J
4. Non-destructive 3D shape measurement of transparent and black objects with thermal fringes
Brahm, Anika; Rößler, Conrad; Dietrich, Patrick; Heist, Stefan; Kühmstedt, Peter; Notni, Gunther
2016-05-01
Fringe projection is a well-established optical method for the non-destructive contactless three-dimensional (3D) measurement of object surfaces. Typically, fringe sequences in the visible wavelength range (VIS) are projected onto the surfaces of objects to be measured and are observed by two cameras in a stereo vision setup. The reconstruction is done by finding corresponding pixels in both cameras followed by triangulation. Problems can occur if the properties of some materials disturb the measurements. If the objects are transparent, translucent, reflective, or strongly absorbing in the VIS range, the projected patterns cannot be recorded properly. To overcome these challenges, we present a new alternative approach in the infrared (IR) region of the electromagnetic spectrum. For this purpose, two long-wavelength infrared (LWIR) cameras (7.5 - 13 μm) are used to detect the emitted heat radiation from surfaces which is induced by a pattern projection unit driven by a CO2 laser (10.6 μm). Thus, materials like glass or black objects, e.g. carbon fiber materials, can be measured non-destructively without the need of any additional paintings. We will demonstrate the basic principles of this heat pattern approach and show two types of 3D systems based on a freeform mirror and a GOBO wheel (GOes Before Optics) projector unit.
5. Verification Test Suite (VERTS) For Rail Gun Applications using ALE3D: 2-D Hydrodynamics & Thermal Cases
SciTech Connect
Najjar, F M; Solberg, J; White, D
2008-04-17
A verification test suite has been assessed with primary focus on low reynolds number flow of liquid metals. This is representative of the interface between the armature and rail in gun applications. The computational multiphysics framework, ALE3D, is used. The main objective of the current study is to provide guidance and gain confidence in the results obtained with ALE3D. A verification test suite based on 2-D cases is proposed and includes the lid-driven cavity and the Couette flow are investigated. The hydro and thermal fields are assumed to be steady and laminar in nature. Results are compared with analytical solutions and previously published data. Mesh resolution studies are performed along with various models for the equation of state.
6. 3D COMSOL Simulations for Thermal Deflection of HFIR Fuel Plate in the "Cheverton-Kelley" Experiments
SciTech Connect
Jain, Prashant K; Freels, James D; Cook, David Howard
2012-08-01
Three dimensional simulation capabilities are currently being developed at Oak Ridge National Laboratory using COMSOL Multiphysics, a finite element modeling software, to investigate thermal expansion of High Flux Isotope Reactor (HFIR) s low enriched uranium fuel plates. To validate simulations, 3D models have also been developed for the experimental setup used by Cheverton and Kelley in 1968 to investigate the buckling and thermal deflections of HFIR s highly enriched uranium fuel plates. Results for several simulations are presented in this report, and comparisons with the experimental data are provided when data are available. A close agreement between the simulation results and experimental findings demonstrates that the COMSOL simulations are able to capture the thermal expansion physics accurately and that COMSOL could be deployed as a predictive tool for more advanced computations at realistic HFIR conditions to study temperature-induced fuel plate deflection behavior.
7. Two-photon luminescence thermometry: towards 3D high-resolution thermal imaging of waveguides.
PubMed
He, Ruiyun; Vázquez de Aldana, Javier Rodríguez; Pedrola, Ginés Lifante; Chen, Feng; Jaque, Daniel
2016-07-11
We report on the use of the Erbium-based luminescence thermometry to realize high resolution, three dimensional thermal imaging of optical waveguides. Proof of concept is demonstrated in a 980-nm laser pumped ultrafast laser inscribed waveguide in Er:Yb phosphate glass. Multi-photon microscopy images revealed the existence of well confined intra-waveguide temperature increments as large as 200 °C for moderate 980-nm pump powers of 120 mW. Numerical simulations and experimental data reveal that thermal loading can be substantially reduced if pump events are separated more than the characteristic thermal time that for the waveguides investigated is in the ms time scale. PMID:27410882
8. Thermal expansion in 3d-metal Prussian Blue Analogs-A survey study
SciTech Connect
Adak, Sourav; Daemen, Luke L.; Hartl, Monika; Williams, Darrick; Summerhill, Jennifer; Nakotte, Heinz
2011-11-15
We present a comprehensive study of the structural properties and the thermal expansion behavior of 17 different Prussian Blue Analogs (PBAs) with compositions M{sup II}{sub 3}[(M'){sup III}(CN){sub 6}]{sub 2}.nH{sub 2}O and M{sup II}{sub 2}[Fe{sup II}(CN){sub 6}].nH{sub 2}O, where M{sup II}=Mn, Fe, Co, Ni, Cu and Zn, (M'){sup III}=Co, Fe and n is the number of water molecules, which range from 5 to 18 for these compounds. The PBAs were synthesized via standard chemical precipitation methods, and temperature-dependent X-ray diffraction studies were performed in the temperature range between -150 deg. C (123 K) and room-temperature. The vast majority of the studied PBAs were found to crystallize in cubic structures of space groups Fm3-bar m, F4-bar 3m and Pm3-bar m. The temperature dependence of the lattice parameters was taken to compute an average coefficient of linear thermal expansion in the studied temperature range. Of the 17 compounds, 9 display negative values for the average coefficient of linear thermal expansion, which can be as large as 39.7x{sup 1}0{sup -6} K{sup -1} for Co{sub 3}[Co(CN){sub 6}]{sub 2}.12H{sub 2}O. All of the M{sup II}{sub 3}[Co{sup III}(CN){sub 6}]{sub 2}.nH{sub 2}O compounds show negative thermal expansion behavior, which correlates with the Irving-Williams series for metal complex stability. The thermal expansion behavior for the PBAs of the M{sup II}{sub 3}[Fe{sup III}(CN){sub 6}]{sub 2}.nH{sub 2}O family are found to switch between positive (for M=Mn, Co, Ni) and negative (M=Cu, Zn) behavior, depending on the choice of the metal cation (M). On the other hand, all of the M{sup II}{sub 2}[Fe{sup II}(CN){sub 6}].nH{sub 2}O compounds show positive thermal expansion behavior. - Graphical Abstract: The structure of Prussian Blue analogs (PBAs) consists of two types of metal centered octahedral units connected by cyanide ligand. Lattice and interstitial water molecules are present in these framework structures. All the PBAs of the M{sub 3
9. A Numerical Study on the Thermal Conductivity of 3D Woven C/C Composites at High Temperature
Shigang, Ai; Rujie, He; Yongmao, Pei
2015-12-01
Experimental data for Carbon/Carbon (C/C) constituent materials are combined with a three dimensional steady state heat transfer finite element analysis to demonstrate the average in-plane and out-of-plane thermal conductivities (TCs) of C/C composites. The finite element analysis is carried out at two distinct length scales: (a) a micro scale comparable with the diameter of carbon fibres and (b) a meso scale comparable with the carbon fibre yarns. Micro-scale model calculate the TCs at the fibre yarn scale in the three orthogonal directions ( x, y and z). The output results from the micro-scale model are then incorporated in the meso-scale model to obtain the global TCs of the 3D C/C composite. The simulation results are quite consistent with the theoretical and experimental counterparts reported in references. Based on the numerical approach, TCs of the 3D C/C composite are calculated from 300 to 2500 K. Particular attention is given in elucidating the variations of the TCs with temperature. The multi-scale models provide an efficient approach to predict the TCs of 3D textile materials, which is helpful for the thermodynamic property analysis and structure design of the C/C composites.
10. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite.
PubMed
Zhang, Wei; Bodey, Andrew J; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M; Mi, Jiawei
2016-01-01
Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods. PMID:26725519
11. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite
Zhang, Wei; Bodey, Andrew J.; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M.; Mi, Jiawei
2016-01-01
Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods.
12. Multi-scale Characterisation of the 3D Microstructure of a Thermally-Shocked Bulk Metallic Glass Matrix Composite
PubMed Central
Zhang, Wei; Bodey, Andrew J.; Sui, Tan; Kockelmann, Winfried; Rau, Christoph; Korsunsky, Alexander M.; Mi, Jiawei
2016-01-01
Bulk metallic glass matrix composites (BMGMCs) are a new class of metal alloys which have significantly increased ductility and impact toughness, resulting from the ductile crystalline phases distributed uniformly within the amorphous matrix. However, the 3D structures and their morphologies of such composite at nano and micrometre scale have never been reported before. We have used high density electric currents to thermally shock a Zr-Ti based BMGMC to different temperatures, and used X-ray microtomography, FIB-SEM nanotomography and neutron diffraction to reveal the morphologies, compositions, volume fractions and thermal stabilities of the nano and microstructures. Understanding of these is essential for optimizing the design of BMGMCs and developing viable manufacturing methods. PMID:26725519
13. Processes of Equatorial Thermal Structure: An Analysis of Galileo Temperature Profile with 3-D Model
NASA Technical Reports Server (NTRS)
Majeed, T.; Waite, J. H., Jr.; Bougher, S. W.; Gladstone, G. R.
2005-01-01
The Jupiter Thermosphere General Circulation Model (JTGCM) calculates the global dynamical structure of Jupiter's thermosphere self-consistently with its global thermal structure and composition. The main heat source that drives the thermospheric flow is high-latitude Joule heating. A secondary source of heating is the auroral process of particle precipitation. Global simulations of Jovian thermospheric dynamics indicate strong neutral outflows from the auroral ovals with velocities up to approximately 2 kilometers per second and subsequent convergence and downwelling at the Jovian equator. Such circulation is shown to be an important process for transporting significant amounts of auroral energy to equatorial latitudes and for regulating the global heat budget in a manner consistent with the high thermospheric temperatures observed by the Galileo probe. Adiabatic compression of the neutral atmosphere resulting from downward motion is an important source of equatorial heating (less than 0.06 microbar). The adiabatic heating continues to dominate between 0.06 and 0.2 microbar, but with an addition of comparable heating due to horizontal advection induced by the meridional flow. Thermal conduction plays an important role in transporting heat down to lower altitudes (greater than 0.2microbar) where it is balanced by the cooling associated with the wind transport processes. Interestingly, we find that radiative cooling caused by H3(+), CH4, and C2H2 emissions does not play a significant role in interpreting the Galileo temperature profile.
14. Code System for 2-Group, 3D Neutronic Kinetics Calculations Coupled to Core Thermal Hydraulics.
2000-05-12
Version 00 QUARK is a combined computer program comprising a revised version of the QUANDRY three-dimensional, two-group neutron kinetics code and an upgraded version of the COBRA transient core analysis code (COBRA-EN). Starting from either a critical steady-state (k-effective or critical dilute Boron problem) or a subcritical steady-state (fixed source problem) in a PWR plant, the code allows one to simulate the neutronic and thermal-hydraulic core transient response to reactivity accidents initiated both inside themore » vessel (such as a control rod ejection) and outside the vessel (such as the sudden change of the Boron concentration in the coolant). QUARK output can be used as input to PSR-470/NORMA-FP to perform a subchannel analysis from converged coarse-mesh nodal solutions.« less
15. 3D analysis of thermal and stress evolution during laser cladding of bioactive glass coatings.
PubMed
Krzyzanowski, Michal; Bajda, Szymon; Liu, Yijun; Triantaphyllou, Andrew; Mark Rainforth, W; Glendenning, Malcolm
2016-06-01
Thermal and strain-stress transient fields during laser cladding of bioactive glass coatings on the Ti6Al4V alloy basement were numerically calculated and analysed. Conditions leading to micro-cracking susceptibility of the coating have been investigated using the finite element based modelling supported by experimental results of microscopic investigation of the sample coatings. Consecutive temperature and stress peaks are developed within the cladded material as a result of the laser beam moving along the complex trajectory, which can lead to micro-cracking. The preheated to 500°C base plate allowed for decrease of the laser power and lowering of the cooling speed between the consecutive temperature peaks contributing in such way to achievement of lower cracking susceptibility. The cooling rate during cladding of the second and the third layer was lower than during cladding of the first one, in such way, contributing towards improvement of cracking resistance of the subsequent layers due to progressive accumulation of heat over the process.
16. Mathematical analysis of the accordion grating illusion: a differential geometry approach to introduce the 3D aperture problem.
PubMed
Yazdanbakhsh, Arash; Gori, Simone
2011-12-01
When an observer moves towards a square-wave grating display, a non-rigid distortion of the pattern occurs in which the stripes bulge and expand perpendicularly to their orientation; these effects reverse when the observer moves away. Such distortions present a new problem beyond the classical aperture problem faced by visual motion detectors, one we describe as a 3D aperture problem as it incorporates depth signals. We applied differential geometry to obtain a closed form solution to characterize the fluid distortion of the stripes. Our solution replicates the perceptual distortions and enabled us to design a nulling experiment to distinguish our 3D aperture solution from other candidate mechanisms (see Gori et al. (in this issue)). We suggest that our approach may generalize to other motion illusions visible in 2D displays. PMID:21782387
17. Mathematical analysis of the accordion grating illusion: a differential geometry approach to introduce the 3D aperture problem.
PubMed
Yazdanbakhsh, Arash; Gori, Simone
2011-12-01
When an observer moves towards a square-wave grating display, a non-rigid distortion of the pattern occurs in which the stripes bulge and expand perpendicularly to their orientation; these effects reverse when the observer moves away. Such distortions present a new problem beyond the classical aperture problem faced by visual motion detectors, one we describe as a 3D aperture problem as it incorporates depth signals. We applied differential geometry to obtain a closed form solution to characterize the fluid distortion of the stripes. Our solution replicates the perceptual distortions and enabled us to design a nulling experiment to distinguish our 3D aperture solution from other candidate mechanisms (see Gori et al. (in this issue)). We suggest that our approach may generalize to other motion illusions visible in 2D displays.
18. Applied Mathematics in EM Studies with Special Emphasis on an Uncertainty Quantification and 3-D Integral Equation Modelling
Pankratov, Oleg; Kuvshinov, Alexey
2016-01-01
Despite impressive progress in the development and application of electromagnetic (EM) deterministic inverse schemes to map the 3-D distribution of electrical conductivity within the Earth, there is one question which remains poorly addressed—uncertainty quantification of the recovered conductivity models. Apparently, only an inversion based on a statistical approach provides a systematic framework to quantify such uncertainties. The Metropolis-Hastings (M-H) algorithm is the most popular technique for sampling the posterior probability distribution that describes the solution of the statistical inverse problem. However, all statistical inverse schemes require an enormous amount of forward simulations and thus appear to be extremely demanding computationally, if not prohibitive, if a 3-D set up is invoked. This urges development of fast and scalable 3-D modelling codes which can run large-scale 3-D models of practical interest for fractions of a second on high-performance multi-core platforms. But, even with these codes, the challenge for M-H methods is to construct proposal functions that simultaneously provide a good approximation of the target density function while being inexpensive to be sampled. In this paper we address both of these issues. First we introduce a variant of the M-H method which uses information about the local gradient and Hessian of the penalty function. This, in particular, allows us to exploit adjoint-based machinery that has been instrumental for the fast solution of deterministic inverse problems. We explain why this modification of M-H significantly accelerates sampling of the posterior probability distribution. In addition we show how Hessian handling (inverse, square root) can be made practicable by a low-rank approximation using the Lanczos algorithm. Ultimately we discuss uncertainty analysis based on stochastic inversion results. In addition, we demonstrate how this analysis can be performed within a deterministic approach. In the
19. Thermal convection in a 3D spherical shell with strongly temperature and pressure dependent viscosity
Stemmer, K.; Harder, H.; Hansen, U.
2004-12-01
The style of convection in planetary mantles is presumably dominated by the strong dependence of the viscosity of the mantle material on temperature and pressure. While several efforts have been undertaken in cartesian geometry to investigate convection in media with strong temperature dependent viscosity, spherical models are still in their infancy and still limited to modest parameters. Spectral approaches are usually employed for spherical convection models which do not allow to take into account lateral variations, like temperature dependent viscosity. We have developed a scheme, based on a finite volume discretization, to treat convection in a spherical shell with strong temperature dependent viscosity. Our approach has been particularly tailored to run efficiently on parallel computers. The spherical shell is topologically divided into six cubes. The equations are formulated in primitive variables, and are treated in the cartesian cubes. In order to ensure mass conservation a SIMPLER pressure correction procedure is applied and to handle strong viscosity variations up to Δ η =106 and high Rayleigh-numbers up to Ra=108 the pressure correction algorithm is combined with a pressure weighted interpolation method to satisfy the incompressibility condition and to avoid oscillations. We study thermal convection in a basal and mixed-mode heated shell with stress free and isothermal boundary conditions, as a function of the Rayleigh-number and viscosity contrast. Besides the temperature dependence we have further explored the effects of pressure on the viscosity. As a general result we observe the existence of three regimes (mobile, sluggish and stagnant lid), characterized by the type of surface motion. Laterally averaged depth-profiles of velocity, temperature and viscosity exhibit significant deviations from the isoviscous case. As compared to cartesian geometries, convection in a spherical shell possesses strong memory for the initial state. At strong
20. RELAP5-3D thermal hydraulic analysis of the target cooling system in the SPES experimental facility
Giardina, M.; Castiglia, F.; Buffa, P.; Palermo, G.; Prete, G.
2014-11-01
The SPES (Selective Production of Exotic Species) experimental facility, under construction at the Italian National Institute of Nuclear Physics (INFN) Laboratories of Legnaro, Italy, is a second generation Isotope Separation On Line (ISOL) plant for advanced nuclear physic studies. The UCx target-ion source system works at temperature of about 2273 K, producing a high level of radiation (105 Sv/h), for this reason a careful risk analysis for the target chamber is among the major safety issues. In this paper, the obtained results of thermofluid-dynamics simulations of accidental transients in the SPES target cooling system are reported. The analysis, performed by using the RELAP5-3D 2.4.2 qualified thermal-hydraulic system code, proves good safety performance of this system during different accidental conditions.
1. Wave propagation analysis of quasi-3D FG nanobeams in thermal environment based on nonlocal strain gradient theory
2016-09-01
This article examines the application of nonlocal strain gradient elasticity theory to wave dispersion behavior of a size-dependent functionally graded (FG) nanobeam in thermal environment. The theory contains two scale parameters corresponding to both nonlocal and strain gradient effects. A quasi-3D sinusoidal beam theory considering shear and normal deformations is employed to present the formulation. Mori-Tanaka micromechanical model is used to describe functionally graded material properties. Hamilton's principle is employed to obtain the governing equations of nanobeam accounting for thickness stretching effect. These equations are solved analytically to find the wave frequencies and phase velocities of the FG nanobeam. It is indicated that wave dispersion behavior of FG nanobeams is significantly affected by temperature rise, nonlocality, length scale parameter and material composition.
2. 3-D Seismic Interpretation
Moore, Gregory F.
2009-05-01
This volume is a brief introduction aimed at those who wish to gain a basic and relatively quick understanding of the interpretation of three-dimensional (3-D) seismic reflection data. The book is well written, clearly illustrated, and easy to follow. Enough elementary mathematics are presented for a basic understanding of seismic methods, but more complex mathematical derivations are avoided. References are listed for readers interested in more advanced explanations. After a brief introduction, the book logically begins with a succinct chapter on modern 3-D seismic data acquisition and processing. Standard 3-D acquisition methods are presented, and an appendix expands on more recent acquisition techniques, such as multiple-azimuth and wide-azimuth acquisition. Although this chapter covers the basics of standard time processing quite well, there is only a single sentence about prestack depth imaging, and anisotropic processing is not mentioned at all, even though both techniques are now becoming standard.
3. Analysis of Age-Related Changes in Asian Facial Skeletons Using 3D Vector Mathematics on Picture Archiving and Communication System Computed Tomography
PubMed Central
Kim, Soo Jin; Kim, So Jung; Park, Jee Soo; Byun, Sung Wan
2015-01-01
Purpose There are marked differences in facial skeletal characteristics between Asian and Caucasian. However, ethnic differences in age-related facial skeletal changes have not yet been fully established. The aims of this study were to evaluate age-related changes in Asian midfacial skeletons and to explore ethnic differences in facial skeletal structures with aging between Caucasian and Asian. Materials and Methods The study included 108 men (aged 20-79 years) and 115 women (aged 20-81 years). Axial CT images with a gantry tilt angle of 0 were analyzed. We measured three-dimensional (3D) coordinates at each point with a pixel lens cursor in a picture archiving and communication system (PACS), and angles and widths between the points were calculated using 3D vector mathematics. We analyzed angular changes in 4 bony regions, including the glabellar, orbital, maxillary, and pyriform aperture regions, and changes in the orbital aperture width (distance from the posterior lacrimal crest to the frontozygomatic suture) and the pyriform width (between both upper margins of the pyriform aperture). Results All 4 midfacial angles in females and glabellar and maxillary angles in males showed statistically significant decreases with aging. On the other hand, the orbital and pyriform widths did not show statistically significant changes with aging. Conclusion The results of this study suggest that Asian midfacial skeletons may change continuously throughout life, and that there may be significant differences in the midfacial skeleton between both sexes and between ethnic groups. PMID:26256986
4. Influence of ultrasound power on acoustic streaming and micro-bubbles formations in a low frequency sono-reactor: mathematical and 3D computational simulation.
PubMed
Sajjadi, Baharak; Raman, Abdul Aziz Abdul; Ibrahim, Shaliza
2015-05-01
This paper aims at investigating the influence of ultrasound power amplitude on liquid behaviour in a low-frequency (24 kHz) sono-reactor. Three types of analysis were employed: (i) mechanical analysis of micro-bubbles formation and their activities/characteristics using mathematical modelling. (ii) Numerical analysis of acoustic streaming, fluid flow pattern, volume fraction of micro-bubbles and turbulence using 3D CFD simulation. (iii) Practical analysis of fluid flow pattern and acoustic streaming under ultrasound irradiation using Particle Image Velocimetry (PIV). In mathematical modelling, a lone micro bubble generated under power ultrasound irradiation was mechanistically analysed. Its characteristics were illustrated as a function of bubble radius, internal temperature and pressure (hot spot conditions) and oscillation (pulsation) velocity. The results showed that ultrasound power significantly affected the conditions of hotspots and bubbles oscillation velocity. From the CFD results, it was observed that the total volume of the micro-bubbles increased by about 4.95% with each 100 W-increase in power amplitude. Furthermore, velocity of acoustic streaming increased from 29 to 119 cm/s as power increased, which was in good agreement with the PIV analysis.
5. Characterization of the 3D distribution of ozone and coarse aerosols in the Troposphere using IASI thermal infrared satellite observations
Cuesta, J.; Eremenko, M.; Dufour, G.; Hoepfner, M.; Orphal, J.
2012-04-01
Both tropospheric ozone and aerosols significantly affect air quality in megacities during pollution events. Moreover, living conditions may be seriously aggravated when such agglomerations are affected by wildfires (e.g. Russian fires over Moscow in 2010), which produce smoke and pollutant precursors, or even during dense desert dust outbreaks (e.g. recurrently over Beijing or Cairo). Moreover, since aerosols diffuse and absorb solar radiation, they have a direct impact on the photochemical production of tropospheric ozone. These interactions during extreme events of high aerosol loads are nowadays poorly known, even though they may significantly affect the tropospheric photochemical equilibrium. In order to address these issues, we have developed a new retrieval technique to jointly characterize the 3D distribution of both tropospheric ozone and coarse aerosols, using spaceborne observations of the infrared spectrometer IASI onboard MetOp-A satellite. Our methodology is based on the inversion of Earth radiance spectra in the atmospheric window from 8 to 12 μm measured by IASI and a «Tikhonov-Philipps»-type regularisation with constraints varying in altitude (as in [Eremenko et al., 2008, GRL; Dufour et al., 2010 ACP]) to simultaneously retrieve ozone profiles, aerosol optical depths at 10 μm and aerosol layer effective heights. Such joint retrieval prevents biases in the ozone profile retrieval during high aerosol load conditions. Aerosol retrievals using thermal infrared radiances mainly account for desert dust and the coarse fraction of biomass burning aerosols. We use radiances from 15 micro-windows within the 8-12 μm atmospheric window, which were carefully chosen (following [Worden et al., 2006 JGR]) for extracting the maximum information on aerosols and ozone and minimizing contamination by other species. We use the radiative transfer code KOPRA, including line-by-line calculations of gas absorption and single scattering for aerosols [Hoepfner et al
6. Near-thermal reactions of Au(+)(1S,3D) with CH3X (X = F,Cl).
PubMed
Taylor, William S; Matthews, Cullen C; Hicks, Ashley J; Fancher, Kendall G; Chen, Li Chen
2012-01-26
Reactions of Au(+)((1)S) and Au(+)((3)D) with CH(3)F and CH(3)Cl have been carried out in a drift cell in He at a pressure of 3.5 Torr at both room temperature and reduced temperatures in order to explore the influence of the electronic state of the metal on reaction outcomes. State-specific product channels and overall two-body rate constants were identified using electronic state chromatography. These results indicate that Au(+)((1)S) reacts to yield an association product in addition to AuCH(2)(+) in parallel steps with both neutrals. Product distributions for association vs HX elimination were determined to be 79% association/21% HX elimination for X = F and 50% association/50% HX elimination when X = Cl. Reaction of Au(+)((3)D) with CH(3)F also results in HF elimination, which in this case is thought to produce (3)AuCH(2)(+). With CH(3)Cl, Au(+)((3)D) reacts to form AuCH(3)(+) and CH(3)Cl(+) in parallel steps. An additional product channel initiated by Au(+)((3)D) is also observed with both methyl halides, which yields CH(2)X(+) as a higher-order product. Kinetic measurements indicate that the reaction efficiency for both Au(+) states is significantly greater with CH(3)Cl than with CH(3)F. The observed two-body rate constant for depletion of Au(+)((1)S) by CH(3)F represents less than 5% of the limiting rate constant predicted by the average dipole orientation model (ADO) at room temperature and 226 K, whereas CH(3)Cl reacts with Au(+)((1)S) at the ADO limit at both room temperature and 218 K. Rate constants for depletion of Au(+)((3)D) by CH(3)F and CH(3)Cl were measured at 226 and 218 K respectively, and indicate that Au(+)((3)D) is consumed at approximately 2% of the ADO limit by CH(3)F and 69% of the ADO limit by CH(3)Cl. Product formation and overall efficiency for all four reactions are consistent with previous experimental results and available theoretical models.
Oldham, Mark
2015-01-01
8. Facile synthesis of 3D porous thermally exfoliated g-C3N4 nanosheet with enhanced photocatalytic degradation of organic dye.
PubMed
Yuan, Xiaoya; Zhou, Chou; Jin, Yanrong; Jing, Qiuye; Yang, Yaling; Shen, Xu; Tang, Qi; Mu, Yuanhua; Du, An-Ke
2016-04-15
3D porous framework composed of exfoliated ultrathin nanosheets is a hot topic in the field of energy storage and conversion. A facile method to prepare 3D mesoporous C3N4 with few-layered nanosheets interconnected in large quantity via H2SO4 intercalation and subsequent thermal treatment was described herein. The obtained thermally-exfoliated C3N4 (TE-C3N4) was thoroughly characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), UV-Vis diffuse reflectance spectroscopy (DRS) and Brunauer-Emmett-Teller (BET) measurements. The detailed analysis indicated that TE-C3N4 possessed enlarged inter-layer space, enhanced UV-light adsorption and high specific surface area with 3D interconnected structure composed of ultrathin 2D nanosheets. Compared to bulk C3N4, TE-C3N4 showed an enhanced photocatalytic activity for photodegradation of Rhodamine B under UV-light irradiation and exhibited no significant loss of photocatalytic activity after 11 recycled runs. The pseudo-first reaction rate constant for TE-C3N4 was about four times higher than that for pure bulk-C3N4. The better photocatalytic performance could be attributed to more active catalytic sites, prolonged photo-excited carrier lifetime and shorted pathway of the carriers to the reaction sites.
9. A 3-D finite-element model for computation of temperature profiles and regions of thermal damage during focused ultrasound surgery exposures.
PubMed
Meaney, P M; Clarke, R L; ter Haar, G R; Rivens, I H
1998-11-01
Although there have been numerous models implemented for modeling thermal diffusion effects during focused ultrasound surgery (FUS), most have limited themselves to representing simple situations for which analytical solutions and the use of cylindrical geometries sufficed. For modeling single lesion formation and the heating patterns from a single exposure, good results were achieved in comparison with experimental results for predicting lesion size, shape and location. However, these types of approaches are insufficient when considering the heating of multiple sites with FUS exposures when the time interval between exposures is short. In such cases, the heat dissipation patterns from initial exposures in the lesion array formation can play a significant role in the heating patterns for later exposures. Understanding the effects of adjacent lesion formation, such as this, requires a three-dimensional (3-D) representation of the bioheat equation. Thus, we have developed a 3-D finite-element representation for modeling the thermal diffusion effects during FUS exposures in clinically relevant tissue volumes. The strength of this approach over past methods is its ability to represent arbitrarily shaped 3-D situations. Initial simulations have allowed calculation of the temperature distribution as a function of time for adjacent FUS exposures in excised bovine liver, with the individually computed point temperatures comparing favorably with published measurements. In addition to modeling these temperature distributions, the model was implemented in conjunction with an algorithm for calculating the thermal dose as a way of predicting lesion shape. Although used extensively in conventional hyperthermia applications, this thermal dose criterion has only been applied in a limited number of simulations in FUS for comparison with experimental measurements. In this study, simulations were run for focal depths 2 and 3 cm below the surface of pig's liver, using multiple
10. Applicability of RELAP5-3D for Thermal-Hydraulic Analyses of a Sodium-Cooled Actinide Burner Test Reactor
SciTech Connect
C. B. Davis
2006-07-01
The Actinide Burner Test Reactor (ABTR) is envisioned as a sodium-cooled, fast reactor that will burn the actinides generated in light water reactors to reduce nuclear waste and ease proliferation concerns. The RELAP5-3D computer code is being considered as the thermal-hydraulic system code to support the development of the ABTR. An evaluation was performed to determine the applicability of RELAP5-3D for the analysis of a sodium-cooled fast reactor. The applicability evaluation consisted of several steps, including identifying the important transients and phenomena expected in the ABTR, identifying the models and correlations that affect the code’s calculation of the important phenomena, and evaluating the applicability of the important models and correlations for calculating the important phenomena expected in the ABTR. The applicability evaluation identified code improvements and additional models needed to simulate the ABTR. The accuracy of the calculated thermodynamic and transport properties for sodium was also evaluated.
11. Major structural features of the northern North Sea and adjacent areas of the continent according to lithosphere-scale 3D density and thermal modelling
Maystrenko, Y. P.; Olesen, O.; Ebbing, J.
2013-12-01
high-density zone (2930 kg/m3) within the continental crystalline crust has been modelled to fit the observed and calculated gravity. The obtained Moho is strongly uplifted beneath the Central and Viking grabens whereas the lithosphere-asthenosphere boundary is relatively shallow beneath the western part of the model area. The next step the study was the 3D thermal modelling. Results of thermal modelling within the upper part of the 3D model indicate that the mainland is generally colder than the basin areas. This regional trend of temperature is mostly related to the low thermal conductivity of sediments which increases heat storage within the areas covered by thick sediments. This thermal effect is especially pronounced within the Central and Viking grabens, the East Shetland and Norwegian-Danish basins where the thickness of the sedimentary cover is highest. At great depths (70-100 km) the temperature distribution roughly reflects the configuration of the lower thermal boundary which is represented by the base of the lithosphere.
12. Deep structure of the northern North Sea and adjacent areas according to regional-scale 3D density and thermal modelling
Maystrenko, Yuriy P.; Olesen, Odleiv; Ebbing, Jörg
2013-04-01
grabens whereas the lithosphere-asthenosphere boundary is relatively shallow beneath the western part of the model area. The next step of the analysis was the 3D thermal modelling. Results of thermal modelling within the upper part of the 3D model indicate that the mainland is generally colder than the basin areas. This regional trend of temperature is mostly related to the low thermal conductivity of sediments which increases heat storage within the areas covered by thick sediments. This thermal effect is especially pronounced within the Central and Viking grabens, the East Shetland and Norwegian-Danish basins where the thickness of the sedimentary cover is highest. At great depths (70-100 km) the temperature distribution roughly reflects the configuration of the lower thermal boundary which is represented by the base of the lithosphere.
13. Rheological variations across an active rift system -- results from lithosphere-scale 3D gravity and thermal models of the Kenya Rift
Meeßen, Christian; Sippel, Judith; Cacace, Mauro; Scheck-Wenderoth, Magdalena; Fishwick, Stewart; Heine, Christian; Strecker, Manfred R.
2015-04-01
Due to its tectono-volcanic activity and economic (geothermal and petroleum) potential, the eastern branch of the East African Rift System (EARS) is one of the best studied extensional systems worldwide and an important natural laboratory for the development of geodynamic concepts on rifting and nascent continental break-up. The Kenya Rift, an integral part of the eastern branch of the EARS, has formed in the area of weak Proterozoic crust of the Mozambique mobile belt adjacent to the rheologically stronger Archean Tanzania craton. To assess the variations in lithospheric strength between different tectonic domains and their influence on the tectonic evolution of the region, we developed a set of structural, density, thermal and rheological 3D models. For these models we integrated multi-disciplinary information, such as published geological field data, sediment thicknesses, well information, existing structural models, seismic refraction and reflection data, seismic tomography, gravity and heat-flow data. Our main approach focused on combined 3D isostatic and gravity modelling. The resulting lithosphere-scale 3D density model provides new insights into the depth distribution of the crust-mantle boundary and thickness variations of different crustal density domains. The latter further facilitate interpretations of variations of lithologies and related physical rock properties. By considering lithology-dependent heat production and thermal conductivity, we calculate the conductive thermal field across the region of the greater Kenya Rift. Finally, the assessed variations in lithology and temperature allow deriving differences in the integrated strength of the lithosphere across the different tectonic domains.
14. 3D rapid mapping
Isaksson, Folke; Borg, Johan; Haglund, Leif
2008-04-01
In this paper the performance of passive range measurement imaging using stereo technique in real time applications is described. Stereo vision uses multiple images to get depth resolution in a similar way as Synthetic Aperture Radar (SAR) uses multiple measurements to obtain better spatial resolution. This technique has been used in photogrammetry for a long time but it will be shown that it is now possible to do the calculations, with carefully designed image processing algorithms, in e.g. a PC in real time. In order to get high resolution and quantitative data in the stereo estimation a mathematical camera model is used. The parameters to the camera model are settled in a calibration rig or in the case of a moving camera the scene itself can be used for calibration of most of the parameters. After calibration an ordinary TV camera has an angular resolution like a theodolite, but to a much lower price. The paper will present results from high resolution 3D imagery from air to ground. The 3D-results from stereo calculation of image pairs are stitched together into a large database to form a 3D-model of the area covered.
15. 3D thermal stress analysis of WIPP (Waste Isolation Pilot Plant) Room T RH TRU (Remote Handled Transuranic) experiments
SciTech Connect
Argueello, J.G.; Beraun, R.; Molecke, M.A.
1989-08-01
A three-dimensional finite element thermal stress analysis of the RH TRU experiments in WIPP Room T has been performed. This analysis aids in the interpretation of the borehole closure results being obtained from the Room T experiments and helps in assessing potential performance impacts in a typical storage room, during the waste retrieval period. Computed results are presented and compared to available in situ data, and a qualitative agreement between measured and computed closures is seen. 9 refs., 10 figs.
16. Research on the aero-thermal effects by 3D analysis model of the optical window of the infrared imaging guidance
Xu, Bo; Li, Lin; Zhu, Ying
2014-11-01
Researches on hypersonic vehicles have been a hotspot in the field of aerospace because of the pursuits for higher speed by human being. Infrared imaging guidance is playing a very important role in modern warfare. When an Infrared Ray(IR) imaging guided missile is flying in the air at high speed, its optical dome suffers from serious aero-optic effects because of air flow. The turbulence around the dome and the thermal effects of the optical window would cause disturbance to the wavefront from the target. Therefore, detected images will be biased, dithered and blurred, and the capabilities of the seeker for detecting, tracking and recognizing are weakened. In this paper, methods for thermal and structural analysis with Heat Transfer and Elastic Mechanics are introduced. By studying the aero-thermal effects and aero-thermal radiation effects of the optical window, a 3D analysis model of the optical window is established by using finite element method. The direct coupling analysis is employed as a solving strategy. The variation regularity of the temperature field is obtained. For light with different incident angles, the influence on the ray propagation caused by window deformation is analyzed with theoretical calculation and optical/thermal/structural integrated analysis method respectively.
17. Application of geologic-mathematical 3D modeling for complex structure deposits by the example of Lower- Cretaceous period depositions in Western Ust - Balykh oil field (Khanty-Mansiysk Autonomous District)
Perevertailo, T.; Nedolivko, N.; Prisyazhnyuk, O.; Dolgaya, T.
2015-11-01
The complex structure of the Lower-Cretaceous formation by the example of the reservoir BC101 in Western Ust - Balykh Oil Field (Khanty-Mansiysk Autonomous District) has been studied. Reservoir range relationships have been identified. 3D geologic- mathematical modeling technique considering the heterogeneity and variability of a natural reservoir structure has been suggested. To improve the deposit geological structure integrity methods of mathematical statistics were applied, which, in its turn, made it possible to obtain equal probability models with similar input data and to consider the formation conditions of reservoir rocks and cap rocks.
18. Facile synthesis of 3D porous thermally exfoliated g-C3N4 nanosheet with enhanced photocatalytic degradation of organic dye.
PubMed
Yuan, Xiaoya; Zhou, Chou; Jin, Yanrong; Jing, Qiuye; Yang, Yaling; Shen, Xu; Tang, Qi; Mu, Yuanhua; Du, An-Ke
2016-04-15
3D porous framework composed of exfoliated ultrathin nanosheets is a hot topic in the field of energy storage and conversion. A facile method to prepare 3D mesoporous C3N4 with few-layered nanosheets interconnected in large quantity via H2SO4 intercalation and subsequent thermal treatment was described herein. The obtained thermally-exfoliated C3N4 (TE-C3N4) was thoroughly characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), UV-Vis diffuse reflectance spectroscopy (DRS) and Brunauer-Emmett-Teller (BET) measurements. The detailed analysis indicated that TE-C3N4 possessed enlarged inter-layer space, enhanced UV-light adsorption and high specific surface area with 3D interconnected structure composed of ultrathin 2D nanosheets. Compared to bulk C3N4, TE-C3N4 showed an enhanced photocatalytic activity for photodegradation of Rhodamine B under UV-light irradiation and exhibited no significant loss of photocatalytic activity after 11 recycled runs. The pseudo-first reaction rate constant for TE-C3N4 was about four times higher than that for pure bulk-C3N4. The better photocatalytic performance could be attributed to more active catalytic sites, prolonged photo-excited carrier lifetime and shorted pathway of the carriers to the reaction sites. PMID:26851454
19. Spatial and Temporal Variability in the Circulation and Thermal Evolution of the Mantle in Subduction Zones: Insights From 3-D Laboratory Experiments.
Kincaid, C.; Griffiths, R. W.
2003-12-01
The subduction of oceanic lithosphere plays a key role in plate tectonics, the thermal evolution of the mantle and recycling processes between Earth's interior and surface. The majority of subduction models are two-dimensional (2-D), assuming limited variability in the direction parallel to the trench. Observationally based models increasingly appeal to three-dimensional (3-D) flow associated with trench migration and the sinking of oceanic plates with a translational component of motion (rollback). We report results from laboratory experiments that reveal fundamental differences in 3-D mantle circulation and temperature structure in response to subduction with and without a rollback component. In our experiments the upper mantle is simulated with glucose syrup and the subducting plate is represented with a Phenolic sheet that is forced to sink into the glucose along prescribed trajectories. An array of 40 thermisters embedded within the plate is used to monitor slab surface temperatures (SSTs). We vary the relative magnitude of downdip and translational components of slab motion and also consider cases where the plate steepens with time. Another parameter is the initial thickness of the thermal boundary layer (TBL) beneath the overriding plate. Without rollback motion, flow in the mantle wedge is sluggish, there is no mass flux around the plate, and plate edges heat up faster than plate centers. Rollback subduction drives flow around and beneath the sinking plate, velocities increase within the mantle wedge and are focussed towards the center of the plate and the surface of the plate heats more along the centerline. In addition to lateral variability in flow and mantle temperatures, results highlight temporal variability in SSTs and 3-D mantle flow trajectories associated with the initiation of subduction and variations between periods of predominantly downdip versus rollback sinking.
20. Assessment of the 3-D Thermal-Hydraulic Nuclear Core Computer Code FLICA-IV on Rod Bundle Experiments
SciTech Connect
Bergeron, Andre; Caruge, Daniel; Clement, Philippe
2001-04-15
The physical validation compared with the hydraulic and two-phase flow experiments of the thermal-hydraulic FLICA-IV nuclear core computer code, in the case of a pressurized water reactor is presented. This three-dimensional two-phase flow code is devoted to steady state and transient thermal-hydraulic analysis of nuclear reactor cores. The four balance equations used by the code and the closure relationships are first presented. Then, the facilities employed for the code validation are described. They are the ones that use either laser velocimetry techniques in the case of hydraulic validation to measure accurately the flow field around rods or isokinetic sampling to carry out the qualities and the axial mass velocities at the outlet of a rod bundle in the case of two-phase flow validation. Comparisons between experimental and computed values are then presented for the axial flow blockage simulation, inlet assemblies flow mixing, axial flow spacer grid disturbance, and an outlet rod bundle map of qualities and axial mass velocities.
1. Moduli thermalization and finite temperature effects in "big" divisor large volume D3/ D7 Swiss-cheese compactification
Shukla, Pramod
2011-01-01
In the context of Type IIB compactified on a large volume Swiss-Cheese orientifold in the presence of a mobile space-time filling D3-brane and stacks of fluxed D7-branes wrapping the "big" divisor Σ B of a Swiss-Cheese Calabi Yau in WCP 4[1, 1, 1, 6, 9], we explore various implications of moduli dynamics and discuss their couplings and decay into MSSM (-like) matter fields early in the history of universe to reach thermal equilibrium. Like finite temperature effects in O'KKLT, we observe that the local minimum of zero-temperature effective scalar potential is stable against any finite temperature corrections (up to two-loops) in large volume scenarios as well. Also we find that moduli are heavy enough to avoid any cosmological moduli problem.
2. Constraints on the Lost City Hydrothermal System from borehole thermal data; 3-D models of heat flow and hydrothermal circulation in an oceanic core complex.
Titarenko, S.; McCaig, A. M.
2014-12-01
A perennial problem in near-ridge hydrothermal circulation is that the only directly measurable data to test models is often vent fluid temperature. Surface heat flow measurements may be available but without the underlying thermal structure it is not known if they are transient and affected by local hydrothermal flow, or conductive. The Atlantis Massif oceanic core complex at 30 °N on the mid-Atlantic Ridge, offers a unique opportunity to better constrain hydrothermal circulation models. The temperature profile in gabbroic rocks of IODP Hole 1309D was measured in IODPExpedition 340T, and found to be near-conductive, but with a slight inflexion at ~750 mbsf indicating downward advection of fluid above that level. The lack of deep convection is especially remarkable given that the long-lived Lost City Hydrothermal Field (LCHF) is located only 5km to the south. We have modelled hydrothermal circulation in the Massif using Comsol Multiphysics, comparing 2-D and 3-D topographic models and using temperature-dependent conductivity to give the best estimate of heatflow into the Massif. We can constrain maximum permeability in gabbro below 750 mbsf to 5e-17 m2. The thermal gradient in the upper part of the borehole can be matched with a permeability of 3e-14 m2 in a 750 m thick layer parallel to the surface of the massif, with upflow occurring in areas of high topography and downflow at the location of the borehole. However in 3-D the precise flow pattern is quite model dependent, and the thermal structure can be matched either by downflow centred on the borehole at lower permeability or centred a few hundred metres from the borehole at higher permeability. The borehole gradient is compatible with the longevity (>120 kyr) and outflow temperature (40-90 °C) of the LCHF either with a deep more permeable (1e-14 m2 to 1e-15 m2) domain beneath the vent site in 2-D or a permeable fault slot 500 to 1000m wide and parallel to the transform fault in 3-D. In both cases topography
3. Monitoring the formation of carbide crystal phases during the thermal decomposition of 3d transition metal dicarboxylate complexes
SciTech Connect
Huba, ZJ; Carpenter, EE
2014-06-06
Single molecule precursors can help to simplify the synthesis of complex alloys by minimizing the amount of necessary starting reagents. However, single molecule precursors are time consuming to prepare with very few being commercially available. In this study, a simple precipitation method is used to prepare Fe, Co, and Ni fumarate and succinate complexes. These complexes were then thermally decomposed in an inert atmosphere to test their efficiency as single molecule precursors for the formation of metal carbide phases. Elevated temperature X-ray diffraction was used to identify the crystal phases produced upon decomposition of the metal dicarboxylate complexes. Thermogravimetric analysis coupled with an infrared detector was used to identify the developed gaseous decomposition products. All complexes tested showed a reduction from the starting M2+ oxidation state to the M oxidation state, upon decomposition. Also, each complex tested showed CO2 and H2O as gaseous decomposition products. Nickel succinate, iron succinate, and iron fumarate complexes were found to form carbide phases upon decomposition. This proves that transition metal dicarboxylate salts can be employed as efficient single molecule precursors for the formation of metal carbide crystal phases.
4. A comparative study of thermal effects of 3 types of laser in eye: 3D simulation with bioheat equation.
PubMed
Joukar, Amin; Nammakie, Erfan; Niroomand-Oscuii, Hanieh
2015-01-01
The application of laser in ophthalmology and eye surgery is so widespread that hardly can anyone deny its importance. On the other hand, since the human eye is an organ susceptible to external factors such as heat waves, laser radiation rapidly increases the temperature of the eye and therefore the study of temperature distribution inside the eye under laser irradiation is crucial; but the use of experimental and invasive methods for measuring the temperature inside the eye is typically high-risk and hazardous. In this paper, using the three-dimensional finite element method, the distribution of heat transfer inside the eye under transient condition was studied through three different lasers named Nd:Yag, Nd:Yap and ArF. Considering the metabolic heat and blood perfusion rate in various regions of the eye, numerical solution of space-time dependant Pennes bioheat transfer equation has been applied in this study. Lambert-Beer's law has been used to model the absorption of laser energy inside the eye tissues. It should also be mentioned that the effect of the ambient temperature, tear evaporation rate, laser power and the pupil diameter on the temperature distribution have been studied. Also, temperature distribution inside the eye after applying each laser and temperature variations of six optional regions as functions of time have been investigated. The results show that these radiations cause temperature rise in various regions, which will in turn causes serious damages to the eye tissues. Investigating the temperature distribution inside the eye under the laser irradiation can be a useful tool to study and predict the thermal effects of laser radiation on the human eye and evaluate the risk involved in performing laser surgery.
5. Measurements and ALE3D Simulations for Violence in a Scaled Thermal Explosion Experiment with LX-10 and AerMet 100 Steel
SciTech Connect
McClelland, M A; Maienschein, J L; Yoh, J J; deHaven, M R; Strand, O T
2005-06-03
We completed a Scaled Thermal Explosion Experiment (STEX) and performed ALE3D simulations for the HMX-based explosive, LX-10, confined in an AerMet 100 (iron-cobalt-nickel alloy) vessel. The explosive was heated at 1 C/h until cookoff at 182 C using a controlled temperature profile. During the explosion, the expansion of the tube and fragment velocities were measured with strain gauges, Photonic-Doppler-Velocimeters (PDVs), and micropower radar units. These results were combined to produce a single curve describing 15 cm of tube wall motion. A majority of the metal fragments were captured and cataloged. A fragment size distribution was constructed, and a typical fragment had a length scale of 2 cm. Based on these results, the explosion was considered to be a violent deflagration. ALE3D models for chemical, thermal, and mechanical behavior were developed for the heating and explosive processes. A four-step chemical kinetics model is employed for the HMX while a one-step model is used for the Viton. A pressure-dependent deflagration model is employed during the expansion. The mechanical behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the equation of state of the solid and gas species, respectively. A gamma-law model is employed for the air in gaps, and a mixed material model is used for the interface between air and explosive. A Johnson-Cook model with an empirical rule for failure strain is used to describe fracture behavior. Parameters for the kinetics model were specified using measurements of the One-Dimensional-Time-to-Explosion (ODTX), while measurements for burn rate were employed to determine parameters in the burn front model. The ALE3D models provide good predictions for the thermal behavior and time to explosion, but the predicted wall expansion curve is higher than the measured curve. Possible contributions to this discrepancy include inaccuracies in the chemical models
6. Studies of a new class of high electro-thermal performing Polyimide embedded with 3D scaffold in the harsh environment of outer space
Loeblein, Manuela; Bolker, Asaf; Tsang, Siu Hon; Atar, Nurit; Uzan-Saguy, Cecile; Verker, Ronen; Gouzman, Irina; Grossman, Eitan; Teo, Edwin Hang Tong
The polymer class of Polyimides (PIs) has been wide-spread in the use of outer space coatings due to their chemical stability and flexibility. Nevertheless, their poor thermal conductivity and completely electrically insulating characteristics have caused severe limitations, such as thermal management challenges and spacecraft electrostatic charging, which forces the use of additional materials such as brittle ITO in order to completely resist the harsh environment of space. For this reason, we developed a new composite material via infiltration of PI with a 3D scaffold which improves PIs performance and resilience and enables the use of only a single flexible material to protect spacecraft. Here we present a study of this new material based on outer-space environment simulated on ground. It includes an exhaustive range of tests simulating space environments in accordance with European Cooperation for Space Standard (ECSS), which includes atomic oxygen (AO) etching, Gamma-ray exposure and outgassing properties over extended periods of time and under strenuous mechanical bending and thermal annealing cycles. Measurement methods for the harsh environment of space and the obtained results will be presented.
7. The Neighboring Column Approximation (NCA) - A fast approach for the calculation of 3D thermal heating rates in cloud resolving models
Klinger, Carolin; Mayer, Bernhard
2016-01-01
Due to computational costs, radiation is usually neglected or solved in plane parallel 1D approximation in today's numerical weather forecast and cloud resolving models. We present a fast and accurate method to calculate 3D heating and cooling rates in the thermal spectral range that can be used in cloud resolving models. The parameterization considers net fluxes across horizontal box boundaries in addition to the top and bottom boundaries. Since the largest heating and cooling rates occur inside the cloud, close to the cloud edge, the method needs in first approximation only the information if a grid box is at the edge of a cloud or not. Therefore, in order to calculate the heating or cooling rates of a specific grid box, only the directly neighboring columns are used. Our so-called Neighboring Column Approximation (NCA) is an analytical consideration of cloud side effects which can be considered a convolution of a 1D radiative transfer result with a kernel or radius of 1 grid-box (5 pt stencil) and which does usually not break the parallelization of a cloud resolving model. The NCA can be easily applied to any cloud resolving model that includes a 1D radiation scheme. Due to the neglect of horizontal transport of radiation further away than one model column, the NCA works best for model resolutions of about 100 m or lager. In this paper we describe the method and show a set of applications of LES cloud field snap shots. Correction terms, gains and restrictions of the NCA are described. Comprehensive comparisons to the 3D Monte Carlo Model MYSTIC and a 1D solution are shown. In realistic cloud fields, the full 3D simulation with MYSTIC shows cooling rates up to -150 K/d (100 m resolution) while the 1D solution shows maximum coolings of only -100 K/d. The NCA is capable of reproducing the larger 3D cooling rates. The spatial distribution of the heating and cooling is improved considerably. Computational costs are only a factor of 1.5-2 higher compared to a 1D
8. Thermal effusivity measurement based on analysis of 3D heat flow by modulated spot heating using a phase lag matrix with a combination of thermal effusivity and volumetric heat capacity
Ohta, Hiromichi; Hatori, Kimihito; Matsui, Genzou; Yagi, Takashi; Miyake, Shugo; Okamura, Takeo; Endoh, Ryo; Okada, Ryo; Morishita, Keisuke; Yokoyama, Shinichiro; Taguchi, Kohei; Kato, Hideyuki
2016-11-01
The study goal was to establish a standard industrial procedure for the measurement of thermal effusivity by a thermal microscope (TM), using a periodic heating method with a thermoreflectance (TR) technique. To accomplish this goal, a working group was organized that included four research institutes. Each institute followed the same procedure: a molybdenum (Mo) film was sputtered on the surface of Pyrex, yttria-stabilized zirconia (YSZ), alumina (Al2O3), Germanium (Ge), and silicon (Si) samples, and then the phase lag of the laser intensity modulation was measured by the resultant surface temperature. A procedure was proposed to calibrate the effect of 3D heat flow, based on the analytical solution of the heat conduction equation, and thermal effusivity was measured. The derived values show good agreement with literature values. As a result, the TM calibration procedure can be recommended for practical use in measuring the thermal effusivity in a small region of the materials.
9. 3D quasi-dynamic modeling of earthquake cycles of the great Tohoku-oki earthquake by considering high-speed friction and thermal pressurization
Shibazaki, B.; Tsutsumi, A.; Shimamoto, T.; Noda, H.
2012-12-01
Some observational studies [e.g. Hasegawa et al., 2011] suggested that the 2011 great Tohoku-oki Earthquake (Mw 9.0) released roughly all of the accumulated elastic strain on the plate interface owing to considerable weakening of the fault. Recent studies show that considerable weakening can occur at a high slip velocity because of thermal pressurization or thermal weakening processes [Noda and Lapusta, 2010; Di Toro et al., 2011]. Tsutsumi et al. [2011] examined the frictional properties of clay-rich fault materials under water-saturated conditions and found that velocity weakening or strengthening occurs at intermediate slip velocities and that dramatic weakening occurs at high slip velocities. This dramatic weakening at higher slip velocities is caused by pore-fluid pressurization via frictional heating or gouge weakening. In the present study, we investigate the generation mechanism of megathrust earthquakes along the Japan trench by performing 3D quasi-dynamic modeling with high-speed friction or thermal pressurization. We propose a rate- and state-dependent friction law with two state variables that exhibit weak velocity weakening or strengthening with a small critical displacement at low to intermediate velocities, but a strong velocity weakening with a large critical displacement at high slip velocities [Shibazaki et al., 2011]. We use this friction law for 3D quasi-dynamic modeling of a cycle of the great Tohoku-oki earthquake. We set several asperities where velocity weakening occurs at low to intermediate slip velocities. Outside of the asperities, velocity strengthening occurs at low to intermediate slip velocities. At high slip velocities, strong velocity weakening occurs both within and outside of the asperities. The rupture of asperities occurs at intervals of several tens of years, whereas megathrust events occur at much longer intervals (several hundred years). Megathrust slips occur even in regions where velocity strengthening occurs at low to
10. Europeana and 3D
Pletinckx, D.
2011-09-01
The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.
11. Mechanochemical and thermal formation of 1H-benzotriazole coordination polymers and complexes of 3d-transition metals with intriguing dielectric properties.
PubMed
Brede, Franziska A; Mühlbach, Friedrich; Sextl, Gerhard; Müller-Buschbaum, Klaus
2016-07-14
Liquid-assisted grinding (LAG) reactions have been successfully applied to achieve a series of complexes and coordination polymers based on divalent 3d-transition metal chlorides (TM chlorides) and the aromatic ligand 1H-benzotriazole (BtzH). The obtained substances were investigated via single crystal X-ray, powder X-ray determination and simultaneous DTA/TG analysis as model compounds for structural and chemical influences on their dielectric properties. Depending on the synthesis method, different constitutions and structures are observed. Two polymorphous forms of the 1D polymer [MnCl2(BtzH)2] (1 and 2) as well as the complexes [ZnCl2(BtzH)2]·BtzH (3) and [CoCl2(BtzH)2]·BtzH (4) have been obtained as phase-pure bulk substances via the mechanochemical LAG route, and even single crystals are available. For comparison, thermal reactions were also carried out and have led to the formation of the neutral complexes: [CoCl2(BtzH)2] (5) and [CoCl2(BtzH)4]·4BtzH (6), [ZnCl2(BtzH)2] (7) and the anionic complex BtzH2[CoCl3BtzH] (8). In addition, thermal treatment of 3 yields the benzotriazolium salt {(BtzH)2H}Cl (9). The transition metal compounds were additionally analysed regarding their dielectric properties by frequency-dependent as well as temperature-dependent permittivity investigations. It is intriguing that compounds 1 and 3 show remarkably low dielectric constants and loss factors up to 50 °C highlighting them as potential "low-k materials".
12. 3-D multi-observable probabilistic inversion for the compositional and thermal structure of the lithosphere and upper mantle. II: General methodology and resolution analysis
Afonso, J. C.; Fullea, J.; Yang, Y.; Connolly, J. A. D.; Jones, A. G.
2013-04-01
Here we present a 3-D multi-observable probabilistic inversion method, particularly designed for high-resolution (regional) thermal and compositional mapping of the lithosphere and sub-lithospheric upper mantle that circumvents the problems associated with traditional inversion methods. The key aspects of the method are as follows: (a) it exploits the increasing amount and quality of geophysical datasets; (b) it combines multiple geophysical observables (Rayleigh and Love dispersion curves, body-wave tomography, magnetotelluric, geothermal, petrological, gravity, elevation, and geoid) with different sensitivities to deep/shallow, thermal/compositional anomalies into a single thermodynamic-geophysical framework; (c) it uses a general probabilistic (Bayesian) formulation to appraise the data; (d) no initial model is needed; (e) compositional a priori information relies on robust statistical analyses of a large database of natural mantle samples; and (f) it provides a natural platform to estimate realistic uncertainties. In addition, the modular nature of the method/algorithm allows for incorporating or isolating specific forward operators according to available data. The strengths and limitations of the method are thoroughly explored with synthetic models. It is shown that the a posteriori probability density function (i.e., solution to the inverse problem) satisfactorily captures spatial variations in bulk composition and temperature with high resolution, as well as sharp discontinuities in these fields. Our results indicate that only temperature anomalies of ΔT ⪆150°C and large compositional anomalies of ΔMg# > 3 (or bulk ΔAl2O3 > 1.5) can be expected to be resolved simultaneously when combining high-quality geophysical data. This resolving power is sufficient to explore some long-standing problems regarding the nature and evolution of the lithosphere (e.g., vertical stratification of cratonic mantle, compositional versus temperature signatures in seismic
13. 3d-3d correspondence revisited
Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr
2016-04-01
In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.
14. 3d-3d correspondence revisited
DOE PAGES
Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr
2016-04-21
In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.
15. Snapshots of Applications in Mathematics: Thermal Systems and the Solar Oven.
ERIC Educational Resources Information Center
Callas, Dennis, Ed.; Hildreth, David J., Ed.; Bickford, Carl
1998-01-01
Showcases applications of mathematics designed to demonstrate to students how the topics under study are used in the real world or to solve problems. Presents an activity on thermal systems using spreadsheets or graphing calculators. (ASK)
16. 3D and Education
Meulien Ohlmann, Odile
2013-02-01
Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?
17. A 3D mathematical model to predict spinal joint and hip joint force for trans-tibial amputees with different SACH foot pylon adjustments.
PubMed
Yu, Chung-huang; Hung, Yu-Cheng; Lin, Yang-Hua; Chen, Guan-Xun; Wei, Shun-Hwa; Huang, Chang-Hung; Chen, Chen-Sheng
2014-09-01
A solid-ankle cushioned heel (SACH) foot is a non-joint foot without natural ankle function. Trans-tibial amputees may occur toe scuffing in the late swing phase due to a lack of active dorsiflexion. To address this problem, clinical guidelines suggests shortening the pylon to produce a smooth gait. However, this causes a leg length discrepancy, induces asymmetry in the hip joint, and causes an overload of L5/S1 joint force. Therefore, this study aimed to investigate the influence of different prosthesis pylons on the hip joint and L5/S1 joint forces. Ten subjects were recruited using leg length for normalisation. Four different pylon reductions (0%, 1%, 2%, and 3%) were used for gait analysis. A Vicon system and force plates were used to collect kinematic data and ground reaction force, respectively. The software package MATLAB was used to create a mathematical model for evaluating the symmetry and force of the hip joint and the low back force of the L5/S1 joint. The model was validated by the correlation coefficient (CC=0.947) and root mean square (RMS=0.028 BW). The model estimated that the 1% group had a symmetrical hip joint force and a lower L5/S1 joint force in the vertical direction. This study indicates that a 1% pylon shortening on a SACH prosthesis is appropriate for a trans-tibial amputee.
18. Derivatives in discrete mathematics: a novel graph-theoretical invariant for generating new 2/3D molecular descriptors. I. Theory and QSPR application.
PubMed
Marrero-Ponce, Yovani; Santiago, Oscar Martínez; López, Yoan Martínez; Barigye, Stephen J; Torrens, Francisco
2012-11-01
In this report, we present a new mathematical approach for describing chemical structures of organic molecules at atomic-molecular level, proposing for the first time the use of the concept of the derivative ([Formula: see text]) of a molecular graph (MG) with respect to a given event (E), to obtain a new family of molecular descriptors (MDs). With this purpose, a new matrix representation of the MG, which generalizes graph's theory's traditional incidence matrix, is introduced. This matrix, denominated the generalized incidence matrix, Q, arises from the Boolean representation of molecular sub-graphs that participate in the formation of the graph molecular skeleton MG and could be complete (representing all possible connected sub-graphs) or constitute sub-graphs of determined orders or types as well as a combination of these. The Q matrix is a non-quadratic and unsymmetrical in nature, its columns (n) and rows (m) are conditions (letters) and collection of conditions (words) with which the event occurs. This non-quadratic and unsymmetrical matrix is transformed, by algebraic manipulation, to a quadratic and symmetric matrix known as relations frequency matrix, F, which characterizes the participation intensity of the conditions (letters) in the events (words). With F, we calculate the derivative over a pair of atomic nuclei. The local index for the atomic nuclei i, Δ(i), can therefore be obtained as a linear combination of all the pair derivatives of the atomic nuclei i with all the rest of the j's atomic nuclei. Here, we also define new strategies that generalize the present form of obtaining global or local (group or atom-type) invariants from atomic contributions (local vertex invariants, LOVIs). In respect to this, metric (norms), means and statistical invariants are introduced. These invariants are applied to a vector whose components are the values Δ(i) for the atomic nuclei of the molecule or its fragments. Moreover, with the purpose of differentiating
19. 3D Printable Graphene Composite.
PubMed
Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong
2015-07-08
In human being's history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today's personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite's linear thermal coefficient is below 75 ppm·°C(-1) from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.
20. 3D Imaging.
ERIC Educational Resources Information Center
Hastings, S. K.
2002-01-01
Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)
1. Understanding the thermal history, exhumation patterns, and role of fault systems on Goodenough Island, Papua New Guinea: Insights from 3D thermo-kinematic modelling
Bermudez, M. A.; Baldwin, S.; Fitzgerald, P. G.; Braun, J.
2012-12-01
The world's youngest eclogites, exhumed from depths of ca. 90 km since 8 Ma, are located in the D'Entrecasteaux Islands in the active Woodlark rift of southeastern Papua New Guinea. These (U)HP rocks formed during/following subduction of Australian margin-derived volcaniclastic sediments, and were exhumed during rifting within the larger, obliquely convergent Australian-Pacific plate boundary zone. Several (U)HP exhumation mechanisms have been proposed including diapiric rise of buoyant crust from mantle to crustal depths, and rifting of heterogeneous crust ahead of the east-to-west propagating Woodlark seafloor spreading center. In order to constrain the relative importance of different exhumation mechanisms through time (i.e., timing and rates of diapirism vs crustal faulting), we apply 3D thermo-kinematic modeling (Pecube) to constrain cooling and exhumation histories derived from thermochronologic data from Goodenough Island, the western-most of the D'Entrecasteaux Islands. More than 500,000 Pecube inverse models were run to evaluate scenarios involving vertical exhumation velocities (i.e., simulating simple buoyancy due to diapirism), low-angle normal faulting and combinations of both processes. These preliminary models assume steady-state topography. Preliminary models (starting at 8 Ma) include: (i) continuous exhumation, (ii) two exhumation phases with different exhumation rates (increasing and/or decreasing), and (iii) three exhumation phases with variable exhumation rates. For buoyancy-only models, the first two scenarios (i and ii) result in poor fits between model-derived and observed (experimental) data. Notably, scenarios (i) and (ii) produce indistinguishable ages for all thermochronologic systems, uniformly long apatite fission-track (AFT) lengths, excessive temperatures at the Moho and geological starting parameters (depth, T) that are not consistent with other data. Scenario (iii) with three exhumation phases has the least misfit between model
2. 3-D multiobservable probabilistic inversion for the compositional and thermal structure of the lithosphere and upper mantle. I: a priori petrological information and geophysical observables
Afonso, J. C.; Fullea, J.; Griffin, W. L.; Yang, Y.; Jones, A. G.; D. Connolly, J. A.; O'Reilly, S. Y.
2013-05-01
of natural mantle samples collected from different tectonic settings (xenoliths, abyssal peridotites, ophiolite samples, etc.). This strategy relaxes more typical and restrictive assumptions such as the use of local/limited xenolith data or compositional regionalizations based on age-composition relations. We demonstrate that the combination of our ρ(m) with a L(m) that exploits the differential sensitivities of specific geophysical observables provides a general and robust inference platform to address the thermochemical structure of the lithosphere and sublithospheric upper mantle. An accompanying paper deals with the integration of these two functions into a general 3-D multiobservable Bayesian inversion method and its computational implementation.
3. Bootstrapping 3D fermions
DOE PAGES
Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran
2016-03-17
We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.
4. Venus in 3D
Plaut, J. J.
1993-08-01
Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.
5. 3D reservoir visualization
SciTech Connect
Van, B.T.; Pajon, J.L.; Joseph, P. )
1991-11-01
This paper shows how some simple 3D computer graphics tools can be combined to provide efficient software for visualizing and analyzing data obtained from reservoir simulators and geological simulations. The animation and interactive capabilities of the software quickly provide a deep understanding of the fluid-flow behavior and an accurate idea of the internal architecture of a reservoir.
6. DYNA3D. Explicit 3-d Hydrodynamic FEM Program
SciTech Connect
Whirley, R.G.; Englemann, B.E. )
1993-11-30
DYNA3D is an explicit, three-dimensional, finite element program for analyzing the large deformation dynamic response of inelastic solids and structures. DYNA3D contains 30 material models and 10 equations of state (EOS) to cover a wide range of material behavior. The material models implemented are: elastic, orthotropic elastic, kinematic/isotropic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, Blatz-Ko rubber, high explosive burn, hydrodynamic without deviatoric stresses, elastoplastic hydrodynamic, temperature-dependent elastoplastic, isotropic elastoplastic, isotropic elastoplastic with failure, soil and crushable foam with failure, Johnson/Cook plasticity model, pseudo TENSOR geological model, elastoplastic with fracture, power law isotropic plasticity, strain rate dependent plasticity, rigid, thermal orthotropic, composite damage model, thermal orthotropic with 12 curves, piecewise linear isotropic plasticity, inviscid two invariant geologic cap, orthotropic crushable model, Moonsy-Rivlin rubber, resultant plasticity, closed form update shell plasticity, and Frazer-Nash rubber model. The hydrodynamic material models determine only the deviatoric stresses. Pressure is determined by one of 10 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, tabulated, and TENSOR pore collapse. DYNA3D generates three binary output databases. One contains information for complete states at infrequent intervals; 50 to 100 states is typical. The second contains information for a subset of nodes and elements at frequent intervals; 1,000 to 10,000 states is typical. The last contains interface data for contact surfaces.
7. A Correction Scheme for Thermal Conductivity Measurement Using the Comparative Cut-bar Technique Based on a 3D Numerical Simulation
SciTech Connect
Douglas W. Marshall; Changhu Xing; Charles Folsom; Colby Jensen; Heng Ban
2014-05-01
As an important factor affecting the accuracy of the thermal conductivity measurement, systematic (bias) error in the guarded comparative axial heat flow (cut-bar) method was mostly neglected by previous researches. This bias is due primarily to the thermal conductivity mismatch between sample and meter bars (reference), which is common for a sample of unknown thermal conductivity. A correction scheme, based on a finite element simulation of the measurement system, was proposed to reduce the magnitude of the overall measurement uncertainty. This scheme was experimentally validated by applying corrections on four types of sample measurements in which the specimen thermal conductivity is much smaller, slightly smaller, equal and much larger than that of the meter bar. As an alternative to the optimum guarding technique proposed before, the correction scheme can be used to minimize uncertainty contribution from the measurement system with non-optimal guarding conditions. It is especially necessary for large thermal conductivity mismatches between sample and meter bars.
8. MNSR transient analyses and thermal hydraulic safety margins for HEU and LEU cores using the RELAP5-3D code
SciTech Connect
Dunn, F.E.; Thomas, J.; Liaw, J.; Matos, J.E.
2008-07-15
For safety analyses to support conversion of MNSR reactors from HEU fuel to LEU fuel, a RELAP5-3D model was set up to simulate the entire MNSR system. This model includes the core, the beryllium reflectors, the water in the tank and the water in the surrounding pool. The MCNP code was used to obtain the power distributions in the core and to obtain reactivity feedback coefficients for the transient analyses. The RELAP5-3D model was validated by comparing measured and calculated data for the NIRR-1 reactor in Nigeria. Comparisons include normal operation at constant power and a 3.77 mk rod withdrawal transient. Excellent agreement was obtained for core coolant inlet and outlet temperatures for operation at constant power, and for power level, coolant inlet temperature, and coolant outlet temperature for the rod withdrawal transient. In addition to the negative reactivity feedbacks from increasing core moderator and fuel temperatures, it was necessary to calculate and include positive reactivity feedback from temperature changes in the radial beryllium reflector and changes in the temperature and density of the water in the tank above the core and at the side of the core. The validated RELAP5-3D model was then used to analyze 3.77 mk rod withdrawal transients for LEU cores with two UO{sub 2} fuel pin designs. The impact of cracking of oxide LEU fuel is discussed. In addition, steady-state power operation at elevated power levels was evaluated to determine steady-state safety margins for onset of nucleate boiling and for onset of significant voiding. (author)
9. Magnetic and Thermal Properties of λ-(BETS)2FeCl4 System ---Fe 3d Spin in Antiferromagnetic Insulating Phase---
Akiba, Hiroshi; Nobori, Kento; Shimada, Kazuo; Nishio, Yutaka; Kajita, Koji; Zhou, Biao; Kobayashi, Akiko; Kobayashi, Hayao
2011-06-01
A quasi-two-dimensional organic conductor λ-(BETS)2FeCl4 [BETS = bis(ethylenedithio)tetraselenafulvalene] exhibits a new type of phase transition from a paramagnetic metal (PM) to an antiferromagnetic insulator (AFI) at a transition temperature (TMI) of 8.3 K under zero magnetic field. We studied its thermodynamic properties and found a six-level Schottky hump in its specific heat and a broad shoulder in its magnetic susceptibility below TMI. These anomalies are explained by a new model in which the 3d spin maintains the paramagnetic states against the antiferromagnetic ordering of the π spin.
10. 3D medical thermography device
2015-05-01
In this paper, a novel handheld 3D medical thermography system is introduced. The proposed system consists of a thermal-infrared camera, a color camera and a depth camera rigidly attached in close proximity and mounted on an ergonomic handle. As a practitioner holding the device smoothly moves it around the human body parts, the proposed system generates and builds up a precise 3D thermogram model by incorporating information from each new measurement in real-time. The data is acquired in motion, thus it provides multiple points of view. When processed, these multiple points of view are adaptively combined by taking into account the reliability of each individual measurement which can vary due to a variety of factors such as angle of incidence, distance between the device and the subject and environmental sensor data or other factors influencing a confidence of the thermal-infrared data when captured. Finally, several case studies are presented to support the usability and performance of the proposed system.
11. 3D Printable Graphene Composite
PubMed Central
Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong
2015-01-01
In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C−1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673
12. 3D Printable Graphene Composite
Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong
2015-07-01
In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.
13. NUBEAM developments and 3d halo modeling
Gorelenkova, M. V.; Medley, S. S.; Kaye, S. M.
2012-10-01
Recent developments related to the 3D halo model in NUBEAM code are described. To have a reliable halo neutral source for diagnostic simulation, the TRANSP/NUBEAM code has been enhanced with full implementation of ADAS atomic physic ground state and excited state data for hydrogenic beams and mixed species plasma targets. The ADAS codes and database provide the density and temperature dependence of the atomic data, and the collective nature of the state excitation process. To be able to populate 3D halo output with sufficient statistical resolution, the capability to control the statistics of fast ion CX modeling and for thermal halo launch has been added to NUBEAM. The 3D halo neutral model is based on modification and extension of the beam in box'' aligned 3d Cartesian grid that includes the neutral beam itself, 3D fast neutral densities due to CX of partially slowed down fast ions in the beam halo region, 3D thermal neutral densities due to CX deposition and fast neutral recapture source. More details on the 3D halo simulation design will be presented.
14. Explicit 3-D Hydrodynamic FEM Program
2000-11-07
DYNA3D is a nonlinear explicit finite element code for analyzing 3-D structures and solid continuum. The code is vectorized and available on several computer platforms. The element library includes continuum, shell, beam, truss and spring/damper elements to allow maximum flexibility in modeling physical problems. Many materials are available to represent a wide range of material behavior, including elasticity, plasticity, composites, thermal effects and rate dependence. In addition, DYNA3D has a sophisticated contact interface capability, includingmore » frictional sliding, single surface contact and automatic contact generation.« less
15. 3D packaging for integrated circuit systems
SciTech Connect
Chu, D.; Palmer, D.W.
1996-11-01
A goal was set for high density, high performance microelectronics pursued through a dense 3D packing of integrated circuits. A {open_quotes}tool set{close_quotes} of assembly processes have been developed that enable 3D system designs: 3D thermal analysis, silicon electrical through vias, IC thinning, mounting wells in silicon, adhesives for silicon stacking, pretesting of IC chips before commitment to stacks, and bond pad bumping. Validation of these process developments occurred through both Sandia prototypes and subsequent commercial examples.
16. Taming supersymmetric defects in 3d-3d correspondence
Gang, Dongmin; Kim, Nakwoo; Romo, Mauricio; Yamazaki, Masahito
2016-07-01
We study knots in 3d Chern-Simons theory with complex gauge group {SL}(N,{{C}}), in the context of its relation with 3d { N }=2 theory (the so-called 3d-3d correspondence). The defect has either co-dimension 2 or co-dimension 4 inside the 6d (2,0) theory, which is compactified on a 3-manifold \\hat{M}. We identify such defects in various corners of the 3d-3d correspondence, namely in 3d {SL}(N,{{C}}) CS theory, in 3d { N }=2 theory, in 5d { N }=2 super Yang-Mills theory, and in the M-theory holographic dual. We can make quantitative checks of the 3d-3d correspondence by computing partition functions at each of these theories. This Letter is a companion to a longer paper [1], which contains more details and more results.
17. An aerial 3D printing test mission
Hirsch, Michael; McGuire, Thomas; Parsons, Michael; Leake, Skye; Straub, Jeremy
2016-05-01
This paper provides an overview of an aerial 3D printing technology, its development and its testing. This technology is potentially useful in its own right. In addition, this work advances the development of a related in-space 3D printing technology. A series of aerial 3D printing test missions, used to test the aerial printing technology, are discussed. Through completing these test missions, the design for an in-space 3D printer may be advanced. The current design for the in-space 3D printer involves focusing thermal energy to heat an extrusion head and allow for the extrusion of molten print material. Plastics can be used as well as composites including metal, allowing for the extrusion of conductive material. A variety of experiments will be used to test this initial 3D printer design. High altitude balloons will be used to test the effects of microgravity on 3D printing, as well as parabolic flight tests. Zero pressure balloons can be used to test the effect of long 3D printing missions subjected to low temperatures. Vacuum chambers will be used to test 3D printing in a vacuum environment. The results will be used to adapt a current prototype of an in-space 3D printer. Then, a small scale prototype can be sent into low-Earth orbit as a 3-U cube satellite. With the ability to 3D print in space demonstrated, future missions can launch production hardware through which the sustainability and durability of structures in space will be greatly improved.
18. 3D Audio System
NASA Technical Reports Server (NTRS)
1992-01-01
Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.
19. Magnetic and orbital orders coupled to negative thermal expansion in Mott insulators, Ca2Ru1--xM xO4 (M = 3d transition metal ion)
Qi, Tongfei
Ca2RuO4 is a structurally-driven Mott insulator with a metal-insulator (MI) transition at TMI = 357K, followed by a well-separated antiferromagnetic order at T N = 110 K. Slightly substituting Ru with a 3d transition metal ion M effectively shifts TMI and induces exotic magnetic behavior below TN. Moreover, M doping for Ru produces negative thermal expansion in Ca2Ru1-- xMxO4 (M = Cr, Mn, Fe or Cu); the lattice volume expands on cooling with a total volume expansion ratio, DeltaV/V, reaching as high as 1%. The onset of the negative thermal expansion closely tracks TMI and TN, sharply contrasting classic negative thermal expansion that shows no relevance to electronic properties. In addition, the observed negative thermal expansion occurs near room temperature and extends over a wide temperature interval. These findings underscores new physics driven by a complex interplay between orbital, spin and lattice degrees of freedom. These materials constitute a new class of Negative Thermal Expansion (NTE) materials with novel electronic and magnetic functions. KEYWORDS: Transition Metal Oxide, Ruthenate, Negative Thermal Expansion, Single crystal XRD, Invar Effect, Orbital Ordering, Magnetic Ordering, Jahn-Teller Effect.
20. 3-D supramolecular architectures in the three new complexes constructed from mixed ligands: Syntheses, crystal structures, spectroscopic properties, XRPD and thermal study
Yang, Guo-Ping; Wang, Yao-Yu; Wang, Hong; Wang, Cui-Juan; Wen, Gui-Lin; Shi, Qi-Zhen; Peng, Shie-Ming
2008-10-01
Three new coordination polymers [Cu 2(bptc) (bpdap) 2]·4H 2O ( 1), {Zn 2(bptc)(bpe)(H 2O) 6} n ( 2) and {Co 2(bptc)(bpe)(H 2O) 8} n ( 3) [H 4bptc = 3,3',4,4'-biphenyltetracarboxylate acid, bpdap = N, N'-bis(2-pyridyl)-2,6-diaminopyridine, bpe = trans-1,2-bis(4-pyridyl)ethene] have been hydrothermally synthesized in different pH values and structurally characterized by single-crystal X-ray diffraction. The non-covalent interactions of hydrogen bond extend complexes 1, 2 and 3 into supramolecular architectures, where 1 exhibits a 3-D framework with 1-D open channels where the guest water molecules are located. Importantly, two kinds of chiral helical H-bonded chains appear in 1, and some types of H-bonded patterns exist in 1, 2 and 3. It is more remarkable that the building block bptc anion adopts versatile coordination modes in these complexes. The elemental analysis, IR spectra, XRPD and TG analysis are discussed for 1, 2 and 3. In addition, the fluorescence is also studied for 2 here.
1. Extra Dimensions: 3D in PDF Documentation
Graf, Norman A.
2012-12-01
2. 3-D transient analysis of pebble-bed HTGR by TORT-TD/ATTICA3D
SciTech Connect
Seubert, A.; Sureda, A.; Lapins, J.; Buck, M.; Bader, J.; Laurien, E.
2012-07-01
As most of the acceptance criteria are local core parameters, application of transient 3-D fine mesh neutron transport and thermal hydraulics coupled codes is mandatory for best estimate evaluations of safety margins. This also applies to high-temperature gas cooled reactors (HTGR). Application of 3-D fine-mesh transient transport codes using few energy groups coupled with 3-D thermal hydraulics codes becomes feasible in view of increasing computing power. This paper describes the discrete ordinates based coupled code system TORT-TD/ATTICA3D that has recently been extended by a fine-mesh diffusion solver. Based on transient analyses for the PBMR-400 design, the transport/diffusion capabilities are demonstrated and 3-D local flux and power redistribution effects during a partial control rod withdrawal are shown. (authors)
3. Imaging mesenchymal stem cells containing single wall nanotube nanoprobes in a 3D scaffold using photo-thermal optical coherence tomography
Connolly, Emma; Subhash, Hrebesh M.; Leahy, Martin; Rooney, Niall; Barry, Frank; Murphy, Mary; Barron, Valerie
2014-02-01
Despite the fact, that a range of clinically viable imaging modalities, such as magnetic resonance imaging (MRI), computed tomography (CT), photo emission tomography (PET), ultrasound and bioluminescence imaging are being optimised to track cells in vivo, many of these techniques are subject to limitations such as the levels of contrast agent required, toxic effects of radiotracers, photo attenuation of tissue and backscatter. With the advent of nanotechnology, nanoprobes are leading the charge to overcome these limitations. In particular, single wall nanotubes (SWNT) have been shown to be taken up by cells and as such are effective nanoprobes for cell imaging. Consequently, the main aim of this research is to employ mesenchymal stem cells (MSC) containing SWNT nanoprobes to image cell distribution in a 3D scaffold for cartilage repair. To this end, MSC were cultured in the presence of 32μg/ml SWNT in cell culture medium (αMEM, 10% FBS, 1% penicillin/streptomycin) for 24 hours. Upon confirmation of cell viability, the MSC containing SWNT were encapsulated in hyaluronic acid gels and loaded on polylactic acid polycaprolactone scaffolds. After 28 days in complete chondrogenic medium, with medium changes every 2 days, chondrogenesis was confirmed by the presence of glycosaminoglycan. Moreover, using photothermal optical coherence tomography (PT-OCT), the cells were seen to be distributed through the scaffold with high resolution. In summary, these data reveal that MSC containing SWNT nanoprobes in combination with PT-OCT offer an exciting opportunity for stem cell tracking in vitro for assessing seeding scaffolds and in vivo for determining biodistribution.
4. The thermal structure and the location of the snow line in the protosolar nebula: Axisymmetric models with full 3-D radiative transfer
Min, M.; Dullemond, C. P.; Kama, M.; Dominik, C.
2011-03-01
The precise location of the water ice condensation front (‘snow line’) in the protosolar nebula has been a debate for a long time. Its importance stems from the expected substantial jump in the abundance of solids beyond the snow line, which is conducive to planet formation, and from the higher ‘stickiness’ in collisions of ice-coated dust grains, which may help the process of coagulation of dust and the formation of planetesimals. In an optically thin nebula, the location of the snow line is easily calculated to be around 3 AU, subject to brightness variations of the young Sun. However, in its first 5-10 myr, the solar nebula was optically thick, implying a smaller snowline radius due to shielding from direct sunlight, but also a larger radius because of viscous heating. Several models have attempted to treat these opposing effects. However, until recently treatments beyond an approximate 1 + 1D radiative transfer were unfeasible. We revisit the problem with a fully self-consistent 3D treatment in an axisymmetric disk model, including a density-dependent treatment of the dust and ice sublimation. We find that the location of the snow line is very sensitive to the opacities of the dust grains and the mass accretion rate of the disk. We show that previous approximate treatments are quite efficient at determining the location of the snow line if the energy budget is locally dominated by viscous accretion. Using this result we derive an analytic estimate of the location of the snow line that compares very well with results from this and previous studies. Using solar abundances of the elements we compute the abundance of dust and ice and find that the expected jump in solid surface density at the snow line is smaller than previously assumed. We further show that in the inner few AU the refractory species are also partly evaporated, leading to a significantly smaller solid state surface density in the regions where the rocky planets were formed.
5. 3-D thermal analysis using finite difference technique with finite element model for improved design of components of rocket engine turbomachines for Space Shuttle Main Engine SSME
NASA Technical Reports Server (NTRS)
Sohn, Kiho D.; Ip, Shek-Se P.
1988-01-01
Three-dimensional finite element models were generated and transferred into three-dimensional finite difference models to perform transient thermal analyses for the SSME high pressure fuel turbopump's first stage nozzles and rotor blades. STANCOOL was chosen to calculate the heat transfer characteristics (HTCs) around the airfoils, and endwall effects were included at the intersections of the airfoils and platforms for the steady-state boundary conditions. Free and forced convection due to rotation effects were also considered in hollow cores. Transient HTCs were calculated by taking ratios of the steady-state values based on the flow rates and fluid properties calculated at each time slice. Results are presented for both transient plots and three-dimensional color contour isotherm plots; they were also converted into universal files to be used for FEM stress analyses.
6. Prominent rocks - 3D
NASA Technical Reports Server (NTRS)
1997-01-01
Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.
Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.
Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right
7. 'Diamond' in 3-D
NASA Technical Reports Server (NTRS)
2004-01-01
This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.
Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.
On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.
The image mosaic is about 6 centimeters (2.4 inches) across.
8. Martian terrain - 3D
NASA Technical Reports Server (NTRS)
1997-01-01
This area of terrain near the Sagan Memorial Station was taken on Sol 3 by the Imager for Mars Pathfinder (IMP). 3D glasses are necessary to identify surface detail.
The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.
Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.
Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right
9. The cryptoendolithic microbial environment in the Ross Desert of Antarctica: mathematical models of the thermal regime
NASA Technical Reports Server (NTRS)
Nienow, J. A.; McKay, C. P.; Friedmann, E. I.
1988-01-01
Microbial activity in the Antarctic cryptoendolithic habitat is regulated primarily by temperature. Previous field studies have provided some information on the thermal regime in this habitat, but this type of information is limited by the remoteness of the site and the harsh climatic conditions. Therefore, a mathematical model of the endolithic thermal regime was constructed to augment the field data. This model enabled the parameters affecting the horizontal and altitudinal distribution of the community to be examined. The model predicts that colonization should be possible on surfaces with zenith angle less than 15 degrees. At greater zenith angles, colonization should be restricted to surfaces with azimuth angles less than 135 degrees or greater than 225 degrees. The upper elevational limit of the community should be less than 2,500 m. The thermal regime probably does not influence the zonation of the community within a rock.
10. The cryptoendolithic microbial environment in the Ross Desert of Antarctica: mathematical models of the thermal regime.
PubMed
Nienow, J A; McKay, C P; Friedmann, E I
1988-01-01
Microbial activity in the Antarctic cryptoendolithic habitat is regulated primarily by temperature. Previous field studies have provided some information on the thermal regime in this habitat, but this type of information is limited by the remoteness of the site and the harsh climatic conditions. Therefore, a mathematical model of the endolithic thermal regime was constructed to augment the field data. This model enabled the parameters affecting the horizontal and altitudinal distribution of the community to be examined. The model predicts that colonization should be possible on surfaces with zenith angle less than 15 degrees. At greater zenith angles, colonization should be restricted to surfaces with azimuth angles less than 135 degrees or greater than 225 degrees. The upper elevational limit of the community should be less than 2,500 m. The thermal regime probably does not influence the zonation of the community within a rock. PMID:11538333
11. The cryptoendolithic microbial environment in the Ross Desert of Antarctica: Mathematical models of the thermal regime.
PubMed
Nienow, J A; McKay, C P; Friedmann, E I
1988-11-01
Microbial activity in the Antarctic cryptoendolithic habitat is regulated primarily by temperature. Previous field studies have provided some information on the thermal regime in this habitat, but this type of information is limited by the remoteness of the site and the harsh climatic conditions. Therefore, a mathematical model of the endolithic thermal regime was constructed to augment the field data. This model enabled the parameters affecting the horizontal and altitudinal distribution of the community to be examined. The model predicts that colonization should be possible on surfaces with zenith angle less than 15°. At greater zenith angles, colonization should be restricted to surfaces with azimuth angles less than 135° or greater than 225°. The upper elevational limit of the community should be less than 2,500 m. The thermal regime probably does not influence the zonation of the community within a rock. PMID:24201713
12. Estimating the relationship between urban 3D morphology and land surface temperature using airborne LiDAR and Landsat-8 Thermal Infrared Sensor data
Lee, J. H.
2015-12-01
Urban forests are known for mitigating the urban heat island effect and heat-related health issues by reducing air and surface temperature. Beyond the amount of the canopy area, however, little is known what kind of spatial patterns and structures of urban forests best contributes to reducing temperatures and mitigating the urban heat effects. Previous studies attempted to find the relationship between the land surface temperature and various indicators of vegetation abundance using remote sensed data but the majority of those studies relied on two dimensional area based metrics, such as tree canopy cover, impervious surface area, and Normalized Differential Vegetation Index, etc. This study investigates the relationship between the three-dimensional spatial structure of urban forests and urban surface temperature focusing on vertical variance. We use a Landsat-8 Thermal Infrared Sensor image (acquired on July 24, 2014) to estimate the land surface temperature of the City of Sacramento, CA. We extract the height and volume of urban features (both vegetation and non-vegetation) using airborne LiDAR (Light Detection and Ranging) and high spatial resolution aerial imagery. Using regression analysis, we apply empirical approach to find the relationship between the land surface temperature and different sets of variables, which describe spatial patterns and structures of various urban features including trees. Our analysis demonstrates that incorporating vertical variance parameters improve the accuracy of the model. The results of the study suggest urban tree planting is an effective and viable solution to mitigate urban heat by increasing the variance of urban surface as well as evaporative cooling effect.
13. Thermal mathematical model correlation through genetic algorithms of an experiment conducted on board the International Space Station
2016-05-01
Genetic algorithms have been used for matching temperature values generated using thermal mathematical models against actual temperatures measured in thermal testing of spacecrafts and space instruments. Up to now, results for small models have been very encouraging. This work will examine the correlation of a small-medium size model, whose thermal test results were available, by means of genetic algorithms. The thermal mathematical model reviewed herein corresponds to Tribolab, a materials experiment deployed on board the International Space Station and subjected to preflight thermal testing. This paper will also discuss in great detail the influence of both the number of reference temperatures available and the number of thermal parameters included in the correlation, taking into account the presence of heat sources and the maximum range of temperature mismatch. Conclusions and recommendations for the thermal test design will be provided, as well as some indications for future improvements.
14. Coupled 3D-neutronics / thermal-hydraulics analysis of an unprotected loss-of-flow accident for a 3600 MWth SFR core
SciTech Connect
Sun, K.; Chenu, A.; Mikityuk, K.; Krepel, J.; Chawla, R.
2012-07-01
The core behaviour of a large (3600 MWth) sodium-cooled fast reactor (SFR) is investigated in this paper with the use of a coupled TRACE/PARCS model. The SFR neutron spectrum is characterized by several performance advantages, but also leads to one dominating neutronics drawback - a positive sodium void reactivity. This implies a positive reactivity effect when sodium coolant is removed from the core. In order to evaluate such feedback in terms of the dynamics, a representative unprotected loss-of-flow (ULOF) transient, i.e. flow run-down without SCRAM in which sodium boiling occurs, is analyzed. Although analysis of a single transient cannot allow general conclusions to be drawn, it does allow better understanding of the underlying physics and can lead to proposals for improving the core response during such an accident. The starting point of this study is the reference core design considered in the framework of the Collaborative Project on the European Sodium Fast Reactor (CP-ESFR). To reduce the void effect, the core has been modified by introducing an upper sodium plenum (along with a boron layer) and by reducing the core height-to-diameter ratio. For the ULOF considered, a sharp increase in core power results in melting of the fuel in the case of the reference core. In the modified core, a large dryout leads to melting of the clad. It seems that, for the hypothetical event considered, fuel failure cannot be avoided with just improvement of the neutronics design; therefore, thermal-hydraulics optimization has been considered. An innovative assembly design is proposed to prevent sodium vapour blocking the fuel channel. This results in preventing a downward propagation of the sodium boiling to the core center, thus limiting it to the upper region. Such a void map introduces a negative coolant density reactivity feedback, which dominates the total reactivity change. As a result, the power level and the fuel temperature are effectively reduced, and a large dryout
15. Extra dimensions: 3D in PDF documentation
SciTech Connect
Graf, Norman A.
2011-01-11
16. Extra dimensions: 3D in PDF documentation
DOE PAGES
Graf, Norman A.
2011-01-11
17. Thermally-induced single-crystal-to-single-crystal transformations from a 2D two-fold interpenetrating square lattice layer to a 3D four-fold interpenetrating diamond framework and its application in dye-sensitized solar cells.
PubMed
Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Wei, Li Guo; Song, Yang; Du, Xi; Xing, Kai; Wang, Ping; Yang, Yu Lin
2016-07-28
In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs. PMID:27356177
18. Thermally-induced single-crystal-to-single-crystal transformations from a 2D two-fold interpenetrating square lattice layer to a 3D four-fold interpenetrating diamond framework and its application in dye-sensitized solar cells.
PubMed
Gao, Song; Fan, Rui Qing; Wang, Xin Ming; Wei, Li Guo; Song, Yang; Du, Xi; Xing, Kai; Wang, Ping; Yang, Yu Lin
2016-07-28
In this work, a rare 2D → 3D single-crystal-to-single-crystal transformation (SCSC) is observed in metal-organic coordination complexes, which is triggered by thermal treatment. The 2D two-fold interpenetrating square lattice layer [Cd(IBA)2]n (1) is irreversibly converted into a 3D four-fold interpenetrating diamond framework {[Cd(IBA)2(H2O)]·2.5H2O}n (2) (HIBA = 4-(1H-imidazol-1-yl)benzoic acid). Consideration is given to these two complexes with different interpenetrating structures and dimensionality, and their influence on photovoltaic properties are studied. Encouraged by the UV-visible absorption and HOMO-LUMO energy states matched for sensitizing TiO2, the two complexes are employed in combination with N719 in dye-sensitized solar cells (DSSCs) to compensate absorption in the ultraviolet and blue-violet region, offset competitive visible light absorption of I3(-) and reducing charge the recombination of injected electrons. After co-sensitization with 1 and 2, the device co-sensitized by 1/N719 and 2/N719 to yield overall efficiencies of 7.82% and 8.39%, which are 19.94% and 28.68% higher than that of the device sensitized only by N719 (6.52%). Consequently, high dimensional interpenetrating complexes could serve as excellent co-sensitizers and have application in DSSCs.
19. A new bioactive Schiff base ligands derived from propylazo-N-pyrimidin-2-yl-benzenesulfonamides Mn(II) and Cu(II) complexes: Synthesis, thermal and spectroscopic characterization biological studies and 3D modeling structures
Tawfik, Abdelrazak M.; El-ghamry, Mosad A.; Abu-El-Wafa, Samy M.; Ahmed, Naglaa M.
2012-11-01
New series of Schiff base ligand H2L and their Cu(II) and Mn(II) complexes derived from azosulfapyrimidine were synthesized and characterized by elemental and thermal studies conductance measurements IR, electronic and EPR spectra. 3D modeling of the ligand indicate that azo group does not participate in complex formation and surface potential on one of the ligand under study indicate that electron density around azomethine groups are much higher than the azo group therefore coordination takes place around azomethine groups. The variety in the geometrical structures depends on the nature of both the metal ions and the Schiff base ligands. The thermo kinetic parameters are calculated and discussed. The biological activities of the ligands and complexes have been screened in vitro against some bacteria and fungi to study their capacity to inhibit their growth and to study the toxicity of the compounds.
20. Thermal contact algorithms in SIERRA mechanics : mathematical background, numerical verification, and evaluation of performance.
SciTech Connect
Copps, Kevin D.; Carnes, Brian R.
2008-04-01
We examine algorithms for the finite element approximation of thermal contact models. We focus on the implementation of thermal contact algorithms in SIERRA Mechanics. Following the mathematical formulation of models for tied contact and resistance contact, we present three numerical algorithms: (1) the multi-point constraint (MPC) algorithm, (2) a resistance algorithm, and (3) a new generalized algorithm. We compare and contrast both the correctness and performance of the algorithms in three test problems. We tabulate the convergence rates of global norms of the temperature solution on sequentially refined meshes. We present the results of a parameter study of the effect of contact search tolerances. We outline best practices in using the software for predictive simulations, and suggest future improvements to the implementation.
1. Thermoelastic characteristics of thermal barrier coatings with layer thickness and edge conditions through mathematical analysis.
PubMed
Go, Jaegwi; Myoung, Sang-Won; Lee, Je-Hyun; Jung, Yeon-Gil; Kim, Seokchan; Paik, Ungyu
2014-10-01
The thermoelastic behaviors of such as temperature distribution, displacements, and stresses in thermal barrier coatings (TBCs) are seriously influenced by top coat thickness and edge conditions, which were investigated based on the thermal and mechanical properties of plasma-sprayed TBCs. A couple of governing partial differential equations were derived based on the thermoelastic theory. Since the governing equations are too involved to solve analytically, a finite volume method was developed to obtain approximations. The thermoelastic characteristics of TBCs with the various thicknesses and microstructures were estimated through mathematical approaches with different edge conditions. The results demonstrated that the top coat thickness and the edge condition in theoretical analysis are crucial factors to be considered in controlling the thermoelastic characteristics of plasma-sprayed TBCs.
2. 3-D Finite Element Heat Transfer
1992-02-01
TOPAZ3D is a three-dimensional implicit finite element computer code for heat transfer analysis. TOPAZ3D can be used to solve for the steady-state or transient temperature field on three-dimensional geometries. Material properties may be temperature-dependent and either isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functionalmore » representation of boundary conditions and internal heat generation. TOPAZ3D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.« less
3. Mathematical simulation of thermal decomposition processes in coking polymers during intense heating
SciTech Connect
Shlenskii, O.F.; Polyakov, A.A.
1994-12-01
Description of nonstationary heat transfer in heat-shielding materials based on cross-linked polymers, mathematical simulation of chemical engineering processes of treating coking and fiery coals, and designing calculations all require taking thermal destruction kinetics into account. The kinetics of chemical transformations affects the substance density change depending on the temperature, the time, the heat-release function, and other properties of materials. The traditionally accepted description of the thermal destruction kinetics of coking materials is based on formulating a set of kinetic equations, in which only chemical transformations are taken into account. However, such an approach does not necessarily agree with the obtained experimental data for the case of intense heating. The authors propose including the parameters characterizing the decrease of intermolecular interaction in a comparatively narrow temperature interval (20-40 K) into the set of kinetic equations. In the neighborhood of a certain temperature T{sub 1}, which is called the limiting temperature of thermal decomposition, a decrease in intermolecular interaction causes an increase in the rates of chemical and phase transformations. The effect of the enhancement of destruction processes has been found experimentally by the contact thermal analysis method.
4. Mathematical model for solar drying of potato cylinders with thermal conductivity radially modulated
Trujillo Arredondo, Mariana
2014-05-01
A mathematical model for drying potato cylinders using solar radiation is proposed and solved analytically. The model incorporates the energy balance for the heat capacity of the potato, the radiation heat transfer from the potato toward the drying chamber and the solar radiation absorbed by the potato during the drying process. Potato cylinders are assumed to exhibit a thermal conductivity which is radially modulated. The method of the Laplace transform, with integral Bromwich and residue theorem will be applied and the analytic solutions for the temperature profiles in the potato cylinder will be derived in the form of an infinite series of Bessel functions, when the thermal conductivity is constant; and in the form of an infinite series of Heun functions, when the thermal conductivity has a linear radial modulation. All computations are performed using computer algebra, specifically Maple. It is expected that the analytical results obtained will be useful in food engineering and industry. Our results suggest some lines for future investigations such as the adoption of more general forms of radial modulation for the thermal conductivity of potato cylinders; and possible applications of other computer algebra software such as Maxima and Mathematica.
5. 3D Elevation Program—Virtual USA in 3D
USGS Publications Warehouse
Lukas, Vicki; Stoker, J.M.
2016-01-01
The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.
6. 3D Elevation Program—Virtual USA in 3D
USGS Publications Warehouse
Lukas, Vicki; Stoker, J.M.
2016-04-14
The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.
7. Evolution of Archaea in 3D modeling
Pikuta, Elena V.; Tankosic, Dragana; Sheldon, Rob
2012-11-01
The analysis of all groups of Archaea performed in two-dimensions have demonstrated a specific distribution of Archaean species as a function of pH/temperature, temperature/salinity and pH/salinity. Work presented here is an extension of this analysis with a three dimensional (3D) modeling in logarithmic scale. As it was shown in 2D representation, the "Rules of the Diagonal" have been expressed even more clearly in 3D modeling. In this article, we used a 3D Mesh modeling to show the range of distribution of each separate group of Archaea as a function of pH, temperature, and salinity. Visible overlap and links between different groups indicate a direction of evolution in Archaea. The major direction in ancestral life (vector of evolution) has been indicated: from high temperature, acidic, and low-salinity system towards low temperature, alkaline and high salinity systems. Specifics of the geometrical coordinates and distribution of separate groups of Archaea in 3 D scale were analyzed with a mathematical description of the functions. Based on the obtained data, a new model for the origin and evolution of life on Earth is proposed. The geometry of this model is described by a hyperboloid of one sheet. Conclusions of this research are consistent with previous results derived from the two-dimensional diagrams. This approach is suggested as a new method for analyzing any biological group in accordance to its environmental parameters.
8. Debris Dispersion Model Using Java 3D
NASA Technical Reports Server (NTRS)
Thirumalainambi, Rajkumar; Bardina, Jorge
2004-01-01
This paper describes web based simulation of Shuttle launch operations and debris dispersion. Java 3D graphics provides geometric and visual content with suitable mathematical model and behaviors of Shuttle launch. Because the model is so heterogeneous and interrelated with various factors, 3D graphics combined with physical models provides mechanisms to understand the complexity of launch and range operations. The main focus in the modeling and simulation covers orbital dynamics and range safety. Range safety areas include destruct limit lines, telemetry and tracking and population risk near range. If there is an explosion of Shuttle during launch, debris dispersion is explained. The shuttle launch and range operations in this paper are discussed based on the operations from Kennedy Space Center, Florida, USA.
9. Market study: 3-D eyetracker
NASA Technical Reports Server (NTRS)
1977-01-01
A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.
10. 3D World Building System
ScienceCinema
None
2016-07-12
This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.
11. 3D World Building System
SciTech Connect
2013-10-30
This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.
12. LLNL-Earth3D
SciTech Connect
2013-10-01
Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.
13. [3-D ultrasound in gastroenterology].
PubMed
Zoller, W G; Liess, H
1994-06-01
Three-dimensional (3D) sonography represents a development of noninvasive diagnostic imaging by real-time two-dimensional (2D) sonography. The use of transparent rotating scans, comparable to a block of glass, generates a 3D effect. The objective of the present study was to optimate 3D presentation of abdominal findings. Additional investigations were made with a new volumetric program to determine the volume of selected findings of the liver. The results were compared with the estimated volumes of 2D sonography and 2D computer tomography (CT). For the processing of 3D images, typical parameter constellations were found for the different findings, which facilitated processing of 3D images. In more than 75% of the cases examined we found an optimal 3D presentation of sonographic findings with respect to the evaluation criteria developed by us for the 3D imaging of processed data. Great differences were found for the estimated volumes of the findings of the liver concerning the three different techniques applied. 3D ultrasound represents a valuable method to judge morphological appearance in abdominal findings. The possibility of volumetric measurements enlarges its potential diagnostic significance. Further clinical investigations are necessary to find out if definite differentiation between benign and malign findings is possible.
14. Euro3D Science Conference
Walsh, J. R.
2004-02-01
The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly
15. 3D printing in dentistry.
PubMed
Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A
2015-12-01
3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery. PMID:26657435
16. PLOT3D user's manual
NASA Technical Reports Server (NTRS)
Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.
1990-01-01
PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.
17. 3D printing in dentistry.
PubMed
Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A
2015-12-01
3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.
18. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)
NASA Technical Reports Server (NTRS)
Buning, P.
1994-01-01
PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into
19. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)
NASA Technical Reports Server (NTRS)
Buning, P.
1994-01-01
PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into
20. Mathematical Modelling of Thermal Process to Aquatic Environment with Different Hydrometeorological Conditions
PubMed Central
Issakhov, Alibek
2014-01-01
This paper presents the mathematical model of the thermal process from thermal power plant to aquatic environment of the reservoir-cooler, which is located in the Pavlodar region, 17 Km to the north-east of Ekibastuz town. The thermal process in reservoir-cooler with different hydrometeorological conditions is considered, which is solved by three-dimensional Navier-Stokes equations and temperature equation for an incompressible flow in a stratified medium. A numerical method based on the projection method, divides the problem into three stages. At the first stage, it is assumed that the transfer of momentum occurs only by convection and diffusion. Intermediate velocity field is solved by fractional steps method. At the second stage, three-dimensional Poisson equation is solved by the Fourier method in combination with tridiagonal matrix method (Thomas algorithm). Finally, at the third stage, it is expected that the transfer is only due to the pressure gradient. Numerical method determines the basic laws of the hydrothermal processes that qualitatively and quantitatively are approximated depending on different hydrometeorological conditions. PMID:24991644
1. Mathematical modelling of thermal process to aquatic environment with different hydrometeorological conditions.
PubMed
Issakhov, Alibek
2014-01-01
This paper presents the mathematical model of the thermal process from thermal power plant to aquatic environment of the reservoir-cooler, which is located in the Pavlodar region, 17 Km to the north-east of Ekibastuz town. The thermal process in reservoir-cooler with different hydrometeorological conditions is considered, which is solved by three-dimensional Navier-Stokes equations and temperature equation for an incompressible flow in a stratified medium. A numerical method based on the projection method, divides the problem into three stages. At the first stage, it is assumed that the transfer of momentum occurs only by convection and diffusion. Intermediate velocity field is solved by fractional steps method. At the second stage, three-dimensional Poisson equation is solved by the Fourier method in combination with tridiagonal matrix method (Thomas algorithm). Finally, at the third stage, it is expected that the transfer is only due to the pressure gradient. Numerical method determines the basic laws of the hydrothermal processes that qualitatively and quantitatively are approximated depending on different hydrometeorological conditions. PMID:24991644
2. The Role of 2D and 3D Mental Rotation in Mathematics for Young Children: What Is It? Why Does It Matter? And What Can We Do about It?
ERIC Educational Resources Information Center
Bruce, Catherine D.; Hawes, Zachary
2015-01-01
The ability to mentally rotate objects in space has been singled out by cognitive scientists as a central metric of spatial reasoning (see Jansen, Schmelter, Quaiser-Pohl, Neuburger, & Heil, 2013; Shepard & Metzler, 1971 for example). However, this is a particularly undeveloped area of current mathematics curricula, especially in North…
3. Unassisted 3D camera calibration
Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.
2012-03-01
With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.
4. Mathematical model of thermal spikes in microwave heating of ceramic oxide fibers
SciTech Connect
Thomas, J.R. Jr.; Unruh, W.P.; Vogt, G.J.
1994-04-01
Experiments on microwave sintering of ceramic fibers in a single-mode cavity have revealed the presence of thermal spikes and hot spots which sometimes travel along the fiber and eventually disappear. They are triggered by relatively small increases in microwave power, and thus have obvious implications for the development of practical microwave-based fiber processing systems. These hot spots are conjectured to originate at slight irregularities in the tow morphology, and propagate as the result of solid phase transitions which take place at elevated temperatures and reduce the dielectric loss coefficient {epsilon}{double_prime}. An elementary mathematical model of the heat transfer process was developed which reproduces the essential features of the observed phenomena, thus lending support to the conjecture. This model is based on the assumption of one-dimensional heat conduction along the axis of the fiber tow, and radiation losses at the surface.
5. On 3-D inelastic analysis methods for hot section components (base program)
NASA Technical Reports Server (NTRS)
Wilson, R. B.; Bak, M. J.; Nakazawa, S.; Banerjee, P. K.
1986-01-01
A 3-D Inelastic Analysis Method program is described. This program consists of a series of new computer codes embodying a progression of mathematical models (mechanics of materials, special finite element, boundary element) for streamlined analysis of: (1) combustor liners, (2) turbine blades, and (3) turbine vanes. These models address the effects of high temperatures and thermal/mechanical loadings on the local (stress/strain)and global (dynamics, buckling) structural behavior of the three selected components. Three computer codes, referred to as MOMM (Mechanics of Materials Model), MHOST (Marc-Hot Section Technology), and BEST (Boundary Element Stress Technology), have been developed and are briefly described in this report.
6. Optical-thermal mathematical model for endovenous laser ablation of varicose veins.
PubMed
van Ruijven, Peter W M; Poluektova, Anna A; van Gemert, Martin J C; Neumann, H A Martino; Nijsten, Tamar; van der Geld, Cees W M
2014-03-01
Endovenous laser ablation (EVLA) is successfully used to treat varicose veins. However, the exact working mechanism is still not fully identified and the clinical procedure is not yet standardized. Mathematical modeling of EVLA could strongly improve our understanding of the influence of the various EVLA processes. The aim of this study is to combine Mordon's optical-thermal model with the presence of a strongly absorbing carbonized blood layer on the fiber tip. The model anatomy includes a cylindrically symmetric blood vessel surrounded by an infinite homogenous perivenous tissue. The optical fiber is located in the center of the vessel and is withdrawn with a pullback velocity. The fiber tip includes a small layer of strongly absorbing material, representing the layer of carbonized blood, which absorbs 45% of the emitted laser power. Heat transfer due to boiling bubbles is taken into account by increasing the heat conduction coefficient by a factor of 200 for temperatures above 95 °C. The temperature distribution in the blood, vessel wall, and surrounding medium is calculated from a numerical solution of the bioheat equation. The simulations were performed in MATLAB™ and validated with the aid of an analytical solution. The simulations showed, first, that laser wavelength did virtually not influence the simulated temperature profiles in blood and vessel wall, and, second, that temperatures of the carbonized blood layer varied slightly, from 952 to 1,104 °C. Our improved mathematical optical-thermal EVLA model confirmed previous predictions and experimental outcomes that laser wavelength is not an important EVLA parameter and that the fiber tip reaches exceedingly high temperatures.
7. Spatially resolved 3D noise
Haefner, David P.; Preece, Bradley L.; Doe, Joshua M.; Burks, Stephen D.
2016-05-01
When evaluated with a spatially uniform irradiance, an imaging sensor exhibits both spatial and temporal variations, which can be described as a three-dimensional (3D) random process considered as noise. In the 1990s, NVESD engineers developed an approximation to the 3D power spectral density (PSD) for noise in imaging systems known as 3D noise. In this correspondence, we describe how the confidence intervals for the 3D noise measurement allows for determination of the sampling necessary to reach a desired precision. We then apply that knowledge to create a smaller cube that can be evaluated spatially across the 2D image giving the noise as a function of position. The method presented here allows for both defective pixel identification and implements the finite sampling correction matrix. In support of the reproducible research effort, the Matlab functions associated with this work can be found on the Mathworks file exchange [1].
8. Autofocus for 3D imaging
Lee-Elkin, Forest
2008-04-01
Three dimensional (3D) autofocus remains a significant challenge for the development of practical 3D multipass radar imaging. The current 2D radar autofocus methods are not readily extendable across sensor passes. We propose a general framework that allows a class of data adaptive solutions for 3D auto-focus across passes with minimal constraints on the scene contents. The key enabling assumption is that portions of the scene are sparse in elevation which reduces the number of free variables and results in a system that is simultaneously solved for scatterer heights and autofocus parameters. The proposed method extends 2-pass interferometric synthetic aperture radar (IFSAR) methods to an arbitrary number of passes allowing the consideration of scattering from multiple height locations. A specific case from the proposed autofocus framework is solved and demonstrates autofocus and coherent multipass 3D estimation across the 8 passes of the "Gotcha Volumetric SAR Data Set" X-Band radar data.
9. Accepting the T3D
SciTech Connect
Rich, D.O.; Pope, S.C.; DeLapp, J.G.
1994-10-01
In April, a 128 PE Cray T3D was installed at Los Alamos National Laboratorys Advanced Computing Laboratory as part of the DOEs High-Performance Parallel Processor Program (H4P). In conjunction with CRI, the authors implemented a 30 day acceptance test. The test was constructed in part to help them understand the strengths and weaknesses of the T3D. In this paper, they briefly describe the H4P and its goals. They discuss the design and implementation of the T3D acceptance test and detail issues that arose during the test. They conclude with a set of system requirements that must be addressed as the T3D system evolves.
10. Mathematical description of the kinetics of the thermal degradation of coals over a wide range of rates of heating
SciTech Connect
Aksenov, L.N.; Bronshtein, A.P.; Zadorina, E.N.; Zagorets, A.M.; Makarov, G.N.; Polyakov, A.A.; Shlenskii, O.F.
1981-01-01
The determination of the most effective regimes for the thermal processing of solid fuels and the control of these processes requires a well-based selection of mathematical models for them. In the reported theoretical study, the question is considered of the possibility of using the traditional equations of chemical kinetics for describing the thermal degradation of the organic matter of coals. Various methods are proposed for the detemination of thermogravimetric curves. 14 refs.
11. VIPRE-01. a thermal-hydraulic analysis code for reactor cores. Volume 1. Mathematical modeling. [PWR; BWR
SciTech Connect
Stewart, C.W.; Cuta, J.M.; Koontz, A.S.; Kelly, J.M.; Basehore, K.L.; George, T.L.; Rowe, D.S.
1983-04-01
VIPRE (Versatile Internals and Component Program for Reactors; EPRI) has been developed for nuclear power utility thermal-hydraulic analysis applications. It is designed to help evaluate nuclear reactor core safety limits including minimum departure from nucleate boiling ratio (MDNBR), critical power ratio (CPR), fuel and clad temperatures, and coolant state in normal operation and assumed accident conditions. This volume (Volume 1: Mathematical Modeling) explains the major thermal hydraulic models and supporting correlations in detail.
12. Combinatorial 3D Mechanical Metamaterials
Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin
2015-03-01
We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.
13. LASTRAC.3d: Transition Prediction in 3D Boundary Layers
NASA Technical Reports Server (NTRS)
Chang, Chau-Lyan
2004-01-01
Langley Stability and Transition Analysis Code (LASTRAC) is a general-purpose, physics-based transition prediction code released by NASA for laminar flow control studies and transition research. This paper describes the LASTRAC extension to general three-dimensional (3D) boundary layers such as finite swept wings, cones, or bodies at an angle of attack. The stability problem is formulated by using a body-fitted nonorthogonal curvilinear coordinate system constructed on the body surface. The nonorthogonal coordinate system offers a variety of marching paths and spanwise waveforms. In the extreme case of an infinite swept wing boundary layer, marching with a nonorthogonal coordinate produces identical solutions to those obtained with an orthogonal coordinate system using the earlier release of LASTRAC. Several methods to formulate the 3D parabolized stability equations (PSE) are discussed. A surface-marching procedure akin to that for 3D boundary layer equations may be used to solve the 3D parabolized disturbance equations. On the other hand, the local line-marching PSE method, formulated as an easy extension from its 2D counterpart and capable of handling the spanwise mean flow and disturbance variation, offers an alternative. A linear stability theory or parabolized stability equations based N-factor analysis carried out along the streamline direction with a fixed wavelength and downstream-varying spanwise direction constitutes an efficient engineering approach to study instability wave evolution in a 3D boundary layer. The surface-marching PSE method enables a consistent treatment of the disturbance evolution along both streamwise and spanwise directions but requires more stringent initial conditions. Both PSE methods and the traditional LST approach are implemented in the LASTRAC.3d code. Several test cases for tapered or finite swept wings and cones at an angle of attack are discussed.
14. From 3D view to 3D print
Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.
2014-08-01
In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers
15. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters
Schild, Jonas; Seele, Sven; Masuch, Maic
2012-03-01
Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.
16. Streamlining of the RELAP5-3D Code
SciTech Connect
Mesina, George L; Hykes, Joshua; Guillen, Donna Post
2007-11-01
RELAP5-3D is widely used by the nuclear community to simulate general thermal hydraulic systems and has proven to be so versatile that the spectrum of transient two-phase problems that can be analyzed has increased substantially over time. To accommodate the many new types of problems that are analyzed by RELAP5-3D, both the physics and numerical methods of the code have been continuously improved. In the area of computational methods and mathematical techniques, many upgrades and improvements have been made decrease code run time and increase solution accuracy. These include vectorization, parallelization, use of improved equation solvers for thermal hydraulics and neutron kinetics, and incorporation of improved library utilities. In the area of applied nuclear engineering, expanded capabilities include boron and level tracking models, radiation/conduction enclosure model, feedwater heater and compressor components, fluids and corresponding correlations for modeling Generation IV reactor designs, and coupling to computational fluid dynamics solvers. Ongoing and proposed future developments include improvements to the two-phase pump model, conversion to FORTRAN 90, and coupling to more computer programs. This paper summarizes the general improvements made to RELAP5-3D, with an emphasis on streamlining the code infrastructure for improved maintenance and development. With all these past, present and planned developments, it is necessary to modify the code infrastructure to incorporate modifications in a consistent and maintainable manner. Modifying a complex code such as RELAP5-3D to incorporate new models, upgrade numerics, and optimize existing code becomes more difficult as the code grows larger. The difficulty of this as well as the chance of introducing errors is significantly reduced when the code is structured. To streamline the code into a structured program, a commercial restructuring tool, FOR_STRUCT, was applied to the RELAP5-3D source files. The
17. Laser printing of 3D metallic interconnects
Beniam, Iyoel; Mathews, Scott A.; Charipar, Nicholas A.; Auyeung, Raymond C. Y.; Piqué, Alberto
2016-04-01
The use of laser-induced forward transfer (LIFT) techniques for the printing of functional materials has been demonstrated for numerous applications. The printing gives rise to patterns, which can be used to fabricate planar interconnects. More recently, various groups have demonstrated electrical interconnects from laser-printed 3D structures. The laser printing of these interconnects takes place through aggregation of voxels of either molten metal or of pastes containing dispersed metallic particles. However, the generated 3D structures do not posses the same metallic conductivity as a bulk metal interconnect of the same cross-section and length as those formed by wire bonding or tab welding. An alternative is to laser transfer entire 3D structures using a technique known as lase-and-place. Lase-and-place is a LIFT process whereby whole components and parts can be transferred from a donor substrate onto a desired location with one single laser pulse. This paper will describe the use of LIFT to laser print freestanding, solid metal foils or beams precisely over the contact pads of discrete devices to interconnect them into fully functional circuits. Furthermore, this paper will also show how the same laser can be used to bend or fold the bulk metal foils prior to transfer, thus forming compliant 3D structures able to provide strain relief for the circuits under flexing or during motion from thermal mismatch. These interconnect "ridges" can span wide gaps (on the order of a millimeter) and accommodate height differences of tens of microns between adjacent devices. Examples of these laser printed 3D metallic bridges and their role in the development of next generation electronics by additive manufacturing will be presented.
18. Remote 3D Medical Consultation
Welch, Greg; Sonnenwald, Diane H.; Fuchs, Henry; Cairns, Bruce; Mayer-Patel, Ketan; Yang, Ruigang; State, Andrei; Towles, Herman; Ilie, Adrian; Krishnan, Srinivas; Söderholm, Hanna M.
Two-dimensional (2D) video-based telemedical consultation has been explored widely in the past 15-20 years. Two issues that seem to arise in most relevant case studies are the difficulty associated with obtaining the desired 2D camera views, and poor depth perception. To address these problems we are exploring the use of a small array of cameras to synthesize a spatially continuous range of dynamic three-dimensional (3D) views of a remote environment and events. The 3D views can be sent across wired or wireless networks to remote viewers with fixed displays or mobile devices such as a personal digital assistant (PDA). The viewpoints could be specified manually or automatically via user head or PDA tracking, giving the remote viewer virtual head- or hand-slaved (PDA-based) remote cameras for mono or stereo viewing. We call this idea remote 3D medical consultation (3DMC). In this article we motivate and explain the vision for 3D medical consultation; we describe the relevant computer vision/graphics, display, and networking research; we present a proof-of-concept prototype system; and we present some early experimental results supporting the general hypothesis that 3D remote medical consultation could offer benefits over conventional 2D televideo.
NASA Technical Reports Server (NTRS)
2002-01-01
In 1999, Genex submitted a proposal to Stennis Space Center for a volumetric 3-D display technique that would provide multiple users with a 360-degree perspective to simultaneously view and analyze 3-D data. The futuristic capabilities of the VolumeViewer(R) have offered tremendous benefits to commercial users in the fields of medicine and surgery, air traffic control, pilot training and education, computer-aided design/computer-aided manufacturing, and military/battlefield management. The technology has also helped NASA to better analyze and assess the various data collected by its satellite and spacecraft sensors. Genex capitalized on its success with Stennis by introducing two separate products to the commercial market that incorporate key elements of the 3-D display technology designed under an SBIR contract. The company Rainbow 3D(R) imaging camera is a novel, three-dimensional surface profile measurement system that can obtain a full-frame 3-D image in less than 1 second. The third product is the 360-degree OmniEye(R) video system. Ideal for intrusion detection, surveillance, and situation management, this unique camera system offers a continuous, panoramic view of a scene in real time.
20. 3D-Printed Microfluidics.
PubMed
Au, Anthony K; Huynh, Wilson; Horowitz, Lisa F; Folch, Albert
2016-03-14
The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite-element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia.
1. Mechanochemical Synthesis of 3d Transition-Metal-1,2,4-Triazole Complexes as Precursors for Microwave-Assisted and Thermal Conversion to Coordination Polymers with a High Influence on the Dielectric Properties.
PubMed
Brede, Franziska A; Heine, Johanna; Sextl, Gerhard; Müller-Buschbaum, Klaus
2016-02-18
The complexes [MCl2 (TzH)4] (M=Mn (1), Fe (2); TzH=1,2,4-1H-triazole) and [ZnCl2 (TzH)2] (3) have been obtained by mechanochemical reactions of the corresponding divalent metal chloride and 1,2,4-1H-triazole. They were successfully used as precursors for the formation of coordination polymers either by a microwave-assisted reaction or by thermal conversion. For manganese, the conversion directly yielded 1∞ [MnCl2 TzH] (4), whereas for the iron-containing precursor, 1∞ [FeCl2 TzH] (6), was formed via the intermediate coordination polymer 1∞ [FeCl(TzH)2]Cl (5). For cobalt, the isotypic polymer 1∞ [CoCl(TzH)2]Cl (7) was obtained, but exclusively by a microwave-induced reaction directly from CoCl2 . The crystal structures were resolved from single crystals and powders. The dielectric properties were determined and revealed large differences in permittivity between the precursor complexes and the rigid chain-like coordination polymers. Whereas the monomeric complexes exhibit very different dielectric behaviour, depending on the transition metal, from "low-k" to "high-k" with the permittivity ranging from 4.3 to >100 for frequencies of up to 1000 Hz, the coordination polymers and complexes with strong intermolecular interactions are all close to "low-k" materials with very low dielectric constants up to 50 °C. Therefore, the conversion procedures can be used to deliberately influence the dielectric properties from complex to polymer and for different 3d transition-metal ions.
2. 3D Computations and Experiments
SciTech Connect
Couch, R; Faux, D; Goto, D; Nikkel, D
2004-04-05
This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.
3. Making Inexpensive 3-D Models
ERIC Educational Resources Information Center
Manos, Harry
2016-01-01
Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…
4. SNL3dFace
2007-07-20
This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial featuresmore » of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.« less
5. SNL3dFace
SciTech Connect
Russ, Trina; Koch, Mark; Koudelka, Melissa; Peters, Ralph; Little, Charles; Boehnen, Chris; Peters, Tanya
2007-07-20
This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial features of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.
6. 3D Printing: Exploring Capabilities
ERIC Educational Resources Information Center
Samuels, Kyle; Flowers, Jim
2015-01-01
As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…
7. Mathematical analysis of thermoelastic characteristics in plasma-sprayed thermal barrier coatings.
PubMed
Go, Jaegwi; Jungo, Yeon-Gil; Kim, Seokchan; Ali, Md Afsar; Paik, Ungyu
2012-02-01
The thermoelastic characteristics of plasma-sprayed thermal barrier coatings (TBCs) have been analyzed using mathematical modeling. Two types of TBC model, cylinder and circular disk which are commercial plasma-sprayed TBCs, subjecting to symmetric temperature distribution to the radial and longitudinal directions, respectively, were taken into consideration. Based on the thermoelastic theories, a second order ordinary differential equation was derived for the cylinder model and a pair of partial differential equations were set up for the circular disk model. The analytic solution was obtained from the ordinary differential equation, while a finite volume method was developed for numerical solutions to the pair of partial differential equations due to the complexity of governing equations. The thermoelastic characteristics of TBC models, such as temperature distributions, displacements, and stresses, were displayed according to the obtained solutions. The rate of heat conduction in the section of the top coat is relatively slow in comparison with the substrate, and no profound difference appears in the temperature distribution between two TBC models. The highest longitudinal tensile stress is expressed at the bond coat of both models, and the substrate is under the compressive stresses to the circumferential direction. While the cylinder expands to the positive longitudinal direction only, the expansion in the circular disk occurs to both the positive and negative longitudinal directions. Relatively large displacement and stresses exhibit in the cylinder as compared with the circular disk. In the circular disk, the stresses to the radial direction undulate at each section, and the displacement profile displays that the width of the circular disk is slightly narrowed. The results demonstrate that the mechanical and thermal properties of the top and bond coats are the crucial factors to be considered in controlling the thermoelastic characteristics of plasma
8. Personalized development of human organs using 3D printing technology.
PubMed
Radenkovic, Dina; Solouk, Atefeh; Seifalian, Alexander
2016-02-01
3D printing is a technique of fabricating physical models from a 3D volumetric digital image. The image is sliced and printed using a specific material into thin layers, and successive layering of the material produces a 3D model. It has already been used for printing surgical models for preoperative planning and in constructing personalized prostheses for patients. The ultimate goal is to achieve the development of functional human organs and tissues, to overcome limitations of organ transplantation created by the lack of organ donors and life-long immunosuppression. We hypothesized a precision medicine approach to human organ fabrication using 3D printed technology, in which the digital volumetric data would be collected by imaging of a patient, i.e. CT or MRI images followed by mathematical modeling to create a digital 3D image. Then a suitable biocompatible material, with an optimal resolution for cells seeding and maintenance of cell viability during the printing process, would be printed with a compatible printer type and finally implanted into the patient. Life-saving operations with 3D printed implants were already performed in patients. However, several issues need to be addressed before translational application of 3D printing into clinical medicine. These are vascularization, innervation, and financial cost of 3D printing and safety of biomaterials used for the construct. PMID:26826637
9. Personalized development of human organs using 3D printing technology.
PubMed
Radenkovic, Dina; Solouk, Atefeh; Seifalian, Alexander
2016-02-01
3D printing is a technique of fabricating physical models from a 3D volumetric digital image. The image is sliced and printed using a specific material into thin layers, and successive layering of the material produces a 3D model. It has already been used for printing surgical models for preoperative planning and in constructing personalized prostheses for patients. The ultimate goal is to achieve the development of functional human organs and tissues, to overcome limitations of organ transplantation created by the lack of organ donors and life-long immunosuppression. We hypothesized a precision medicine approach to human organ fabrication using 3D printed technology, in which the digital volumetric data would be collected by imaging of a patient, i.e. CT or MRI images followed by mathematical modeling to create a digital 3D image. Then a suitable biocompatible material, with an optimal resolution for cells seeding and maintenance of cell viability during the printing process, would be printed with a compatible printer type and finally implanted into the patient. Life-saving operations with 3D printed implants were already performed in patients. However, several issues need to be addressed before translational application of 3D printing into clinical medicine. These are vascularization, innervation, and financial cost of 3D printing and safety of biomaterials used for the construct.
10. DRACO development for 3D simulations
2006-10-01
The DRACO (r-z) lagrangian radiation-hydrodynamics laser fusion simulation code is being extended to model 3D hydrodynamics in (x-y-z) coordinates with hexahedral cells on a structured grid. The equation of motion is solved with a lagrangian update with optional rezoning. The fluid equations are solved using an explicit scheme based on (Schulz, 1964) while the SALE-3D algorithm (Amsden, 1981) is used as a template for computing cell volumes and other quantities. A second order rezoner has been added which uses linear interpolation of the underlying continuous functions to preserve accuracy (Van Leer, 1976). Artificial restoring force terms and smoothing algorithms are used to avoid grid distortion in high aspect ratio cells. These include alternate node couplers along with a rotational restoring force based on the Tensor Code (Maenchen, 1964). Electron and ion thermal conduction is modeled using an extension of Kershaw's method (Kershaw, 1981) to 3D geometry. Test problem simulations will be presented to demonstrate the applicability of this new version of DRACO to the study of fluid instabilities in three dimensions.
11. TACO3D. 3-D Finite Element Heat Transfer Code
SciTech Connect
Mason, W.E.
1992-03-04
TACO3D is a three-dimensional, finite-element program for heat transfer analysis. An extension of the two-dimensional TACO program, it can perform linear and nonlinear analyses and can be used to solve either transient or steady-state problems. The program accepts time-dependent or temperature-dependent material properties, and materials may be isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions and loadings are available including temperature, flux, convection, and radiation boundary conditions and internal heat generation. Additional specialized features treat enclosure radiation, bulk nodes, and master/slave internal surface conditions (e.g., contact resistance). Data input via a free-field format is provided. A user subprogram feature allows for any type of functional representation of any independent variable. A profile (bandwidth) minimization option is available. The code is limited to implicit time integration for transient solutions. TACO3D has no general mesh generation capability. Rows of evenly-spaced nodes and rows of sequential elements may be generated, but the program relies on separate mesh generators for complex zoning. TACO3D does not have the ability to calculate view factors internally. Graphical representation of data in the form of time history and spatial plots is provided through links to the POSTACO and GRAPE postprocessor codes.
12. 3D Integration for Wireless Multimedia
Kimmich, Georg
The convergence of mobile phone, internet, mapping, gaming and office automation tools with high quality video and still imaging capture capability is becoming a strong market trend for portable devices. High-density video encode and decode, 3D graphics for gaming, increased application-software complexity and ultra-high-bandwidth 4G modem technologies are driving the CPU performance and memory bandwidth requirements close to the PC segment. These portable multimedia devices are battery operated, which requires the deployment of new low-power-optimized silicon process technologies and ultra-low-power design techniques at system, architecture and device level. Mobile devices also need to comply with stringent silicon-area and package-volume constraints. As for all consumer devices, low production cost and fast time-to-volume production is key for success. This chapter shows how 3D architectures can bring a possible breakthrough to meet the conflicting power, performance and area constraints. Multiple 3D die-stacking partitioning strategies are described and analyzed on their potential to improve the overall system power, performance and cost for specific application scenarios. Requirements and maturity of the basic process-technology bricks including through-silicon via (TSV) and die-to-die attachment techniques are reviewed. Finally, we highlight new challenges which will arise with 3D stacking and an outlook on how they may be addressed: Higher power density will require thermal design considerations, new EDA tools will need to be developed to cope with the integration of heterogeneous technologies and to guarantee signal and power integrity across the die stack. The silicon/wafer test strategies have to be adapted to handle high-density IO arrays, ultra-thin wafers and provide built-in self-test of attached memories. New standards and business models have to be developed to allow cost-efficient assembly and testing of devices from different silicon and technology
13. 3D reconstruction of tensors and vectors
SciTech Connect
Defrise, Michel; Gullberg, Grant T.
2005-02-17
Here we have developed formulations for the reconstruction of 3D tensor fields from planar (Radon) and line-integral (X-ray) projections of 3D vector and tensor fields. Much of the motivation for this work is the potential application of MRI to perform diffusion tensor tomography. The goal is to develop a theory for the reconstruction of both Radon planar and X-ray or line-integral projections because of the flexibility of MRI to obtain both of these type of projections in 3D. The development presented here for the linear tensor tomography problem provides insight into the structure of the nonlinear MRI diffusion tensor inverse problem. A particular application of tensor imaging in MRI is the potential application of cardiac diffusion tensor tomography for determining in vivo cardiac fiber structure. One difficulty in the cardiac application is the motion of the heart. This presents a need for developing future theory for tensor tomography in a motion field. This means developing a better understanding of the MRI signal for diffusion processes in a deforming media. The techniques developed may allow the application of MRI tensor tomography for the study of structure of fiber tracts in the brain, atherosclerotic plaque, and spine in addition to fiber structure in the heart. However, the relations presented are also applicable to other fields in medical imaging such as diffraction tomography using ultrasound. The mathematics presented can also be extended to exponential Radon transform of tensor fields and to other geometric acquisitions such as cone beam tomography of tensor fields.
14. Forensic 3D scene reconstruction
Little, Charles Q.; Small, Daniel E.; Peters, Ralph R.; Rigdon, J. B.
2000-05-01
Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a fieldable prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.
15. Forensic 3D Scene Reconstruction
SciTech Connect
LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.
1999-10-12
Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.
16. 3D Printed Robotic Hand
NASA Technical Reports Server (NTRS)
Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.
2013-01-01
Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was \$167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.
17. 3D light scanning macrography.
PubMed
Huber, D; Keller, M; Robert, D
2001-08-01
The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences. PMID:11489078
18. 3D Model of Surfactant Replacement Therapy
Grotberg, James; Tai, Cheng-Feng; Filoche, Marcel
2015-11-01
Surfactant Replacement Therapy (SRT) involves instillation of a liquid-surfactant mixture directly into the lung airway tree. Though successful in neonatal applications, its use in adults had early success followed by failure. We present the first mathematical model of 3D SRT where a liquid plug propagates through the tree from forced inspiration. In two separate modeling steps, the plug first deposits a coating film on the airway wall which subtracts from its volume, a coating cost''. Then the plug splits unevenly at the airway bifurcation due to gravity. The steps are repeated until a plug ruptures or reaches the tree endpoint alveoli/acinus. The model generates 3D images of the resulting acinar distribution and calculates two global indexes, efficiency and homogeneity. Simulating published literature, the earlier successful adult SRT studies show comparatively good index values, while the later failed studies do not. Those unsuccessful studies used smaller dose volumes with higher concentration mixtures, apparently assuming a well mixed compartment. The model shows that adult lungs are not well mixed in SRT due to the coating cost and gravity effects. Returning to the higher dose volume protocols could save many thousands of lives annually in the US. Supported by NIH Grants HL85156, HL84370 and Agence Nationale de la Recherche, ANR no. 2010-BLAN-1119-05.
19. Dissipation mechanism in 3D magnetic reconnection
SciTech Connect
Fujimoto, Keizo
2011-11-15
Dissipation processes responsible for fast magnetic reconnection in collisionless plasmas are investigated using 3D electromagnetic particle-in-cell simulations. The present study revisits the two simulation runs performed in the previous study (Fujimoto, Phys. Plasmas 16, 042103 (2009)); one with small system size in the current density direction, and the other with larger system size. In the case with small system size, the reconnection processes are almost the same as those in 2D reconnection, while in the other case a kink mode evolves along the current density and deforms the current sheet structure drastically. Although fast reconnection is achieved in both the cases, the dissipation mechanism is very different between them. In the case without kink mode, the electrons transit the electron diffusion region without thermalization, so that the magnetic dissipation is supported by the inertia resistivity alone. On the other hand, in the kinked current sheet, the electrons are not only accelerated in bulk, but they are also partly scattered and thermalized by the kink mode, which results in the anomalous resistivity in addition to the inertia resistivity. It is demonstrated that in 3D reconnection the thickness of the electron current sheet becomes larger than the local electron inertia length, consistent with the theoretical prediction in Fujimoto and Sydora (Phys. Plasmas 16, 112309 (2009)).
20. [Real time 3D echocardiography
NASA Technical Reports Server (NTRS)
Bauer, F.; Shiota, T.; Thomas, J. D.
2001-01-01
Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.
1. [Real time 3D echocardiography].
PubMed
Bauer, F; Shiota, T; Thomas, J D
2001-07-01
Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients. PMID:11494630
2. [Formulation and evalution of a mathematical model to predict losses of nutrients during the thermal processing of canned food].
PubMed
Barreiro, J A; Salas, M G; Herrera Morám, I
1977-09-01
The purpose of this paper was the development of a mathematical model to predict losses of nutrients with first orden degradation kinetics during the thermal processing of conduction-heated foods. The model do not require experimental heat penetration data and operate for any possible case. It was evaluated experimentally for different thermal processes, being all the results within the 90% confidence interval on the mean experimental values. These results were obtained with a Fortran IV computer program elaborated for this purpose. The duration of this program was two minutes and tem seconds in a PDP 11/45 computer and was more efficient than others presented in the literature.
3. GPU-Accelerated Denoising in 3D (GD3D)
2013-10-01
The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer themore » second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.« less
4. Magmatic Systems in 3-D
Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.
2002-12-01
Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated
5. An Evaluative Review of Simulated Dynamic Smart 3d Objects
Romeijn, H.; Sheth, F.; Pettit, C. J.
2012-07-01
Three-dimensional (3D) modelling of plants can be an asset for creating agricultural based visualisation products. The continuum of 3D plants models ranges from static to dynamic objects, also known as smart 3D objects. There is an increasing requirement for smarter simulated 3D objects that are attributed mathematically and/or from biological inputs. A systematic approach to plant simulation offers significant advantages to applications in agricultural research, particularly in simulating plant behaviour and the influences of external environmental factors. This approach of 3D plant object visualisation is primarily evident from the visualisation of plants using photographed billboarded images, to more advanced procedural models that come closer to simulating realistic virtual plants. However, few programs model physical reactions of plants to external factors and even fewer are able to grow plants based on mathematical and/or biological parameters. In this paper, we undertake an evaluation of plant-based object simulation programs currently available, with a focus upon the components and techniques involved in producing these objects. Through an analytical review process we consider the strengths and weaknesses of several program packages, the features and use of these programs and the possible opportunities in deploying these for creating smart 3D plant-based objects to support agricultural research and natural resource management. In creating smart 3D objects the model needs to be informed by both plant physiology and phenology. Expert knowledge will frame the parameters and procedures that will attribute the object and allow the simulation of dynamic virtual plants. Ultimately, biologically smart 3D virtual plants that react to changes within an environment could be an effective medium to visually represent landscapes and communicate land management scenarios and practices to planners and decision-makers.
6. Automatic Reconstruction of Spacecraft 3D Shape from Imagery
Poelman, C.; Radtke, R.; Voorhees, H.
We describe a system that computes the three-dimensional (3D) shape of a spacecraft from a sequence of uncalibrated, two-dimensional images. While the mathematics of multi-view geometry is well understood, building a system that accurately recovers 3D shape from real imagery remains an art. A novel aspect of our approach is the combination of algorithms from computer vision, photogrammetry, and computer graphics. We demonstrate our system by computing spacecraft models from imagery taken by the Air Force Research Laboratory's XSS-10 satellite and DARPA's Orbital Express satellite. Using feature tie points (each identified in two or more images), we compute the relative motion of each frame and the 3D location of each feature using iterative linear factorization followed by non-linear bundle adjustment. The "point cloud" that results from this traditional shape-from-motion approach is typically too sparse to generate a detailed 3D model. Therefore, we use the computed motion solution as input to a volumetric silhouette-carving algorithm, which constructs a solid 3D model based on viewpoint consistency with the image frames. The resulting voxel model is then converted to a facet-based surface representation and is texture-mapped, yielding realistic images from arbitrary viewpoints. We also illustrate other applications of the algorithm, including 3D mensuration and stereoscopic 3D movie generation.
7. Interactive 3D Mars Visualization
NASA Technical Reports Server (NTRS)
Powell, Mark W.
2012-01-01
The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.
NASA Technical Reports Server (NTRS)
2004-01-01
This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.
9. Making Inexpensive 3-D Models
Manos, Harry
2016-03-01
Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.
10. 3D Printed Shelby Cobra
SciTech Connect
Love, Lonnie
2015-01-09
ORNL's newly printed 3D Shelby Cobra was showcased at the 2015 NAIAS in Detroit. This "laboratory on wheels" uses the Shelby Cobra design, celebrating the 50th anniversary of this model and honoring the first vehicle to be voted a national monument. The Shelby was printed at the Department of Energy’s Manufacturing Demonstration Facility at ORNL using the BAAM (Big Area Additive Manufacturing) machine and is intended as a “plug-n-play” laboratory on wheels. The Shelby will allow research and development of integrated components to be tested and enhanced in real time, improving the use of sustainable, digital manufacturing solutions in the automotive industry.
11. Positional Awareness Map 3D (PAM3D)
NASA Technical Reports Server (NTRS)
Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise
2012-01-01
The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.
12. 3D acoustic atmospheric tomography
Rogers, Kevin; Finn, Anthony
2014-10-01
This paper presents a method for tomographically reconstructing spatially varying 3D atmospheric temperature profiles and wind velocity fields based. Measurements of the acoustic signature measured onboard a small Unmanned Aerial Vehicle (UAV) are compared to ground-based observations of the same signals. The frequency-shifted signal variations are then used to estimate the acoustic propagation delay between the UAV and the ground microphones, which are also affected by atmospheric temperature and wind speed vectors along each sound ray path. The wind and temperature profiles are modelled as the weighted sum of Radial Basis Functions (RBFs), which also allow local meteorological measurements made at the UAV and ground receivers to supplement any acoustic observations. Tomography is used to provide a full 3D reconstruction/visualisation of the observed atmosphere. The technique offers observational mobility under direct user control and the capacity to monitor hazardous atmospheric environments, otherwise not justifiable on the basis of cost or risk. This paper summarises the tomographic technique and reports on the results of simulations and initial field trials. The technique has practical applications for atmospheric research, sound propagation studies, boundary layer meteorology, air pollution measurements, analysis of wind shear, and wind farm surveys.
13. Gravitation in 3D Spacetime
Laubenstein, John; Cockream, Kandi
2009-05-01
3D spacetime was developed by the IWPD Scale Metrics (SM) team using a coordinate system that translates n dimensions to n-1. 4-vectors are expressed in 3D along with a scaling factor representing time. Time is not orthogonal to the three spatial dimensions, but rather in alignment with an object's axis-of-motion. We have defined this effect as the object's orientation'' (X). The SM orientation (X) is equivalent to the orientation of the 4-velocity vector positioned tangent to its worldline, where X-1=θ+1 and θ is the angle of the 4-vector relative to the axis-of -motion. Both 4-vectors and SM appear to represent valid conceptualizations of the relationship between space and time. Why entertain SM? Scale Metrics gravity is quantized and may suggest a path for the full unification of gravitation with quantum theory. SM has been tested against current observation and is in agreement with the age of the universe, suggests a physical relationship between dark energy and dark matter, is in agreement with the accelerating expansion rate of the universe, contributes to the understanding of the fine-structure constant and provides a physical explanation of relativistic effects.
14. 3D printed bionic ears.
PubMed
Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C
2013-06-12
The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing.
15. 3D printed bionic ears.
PubMed
Mannoor, Manu S; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A; Soboyejo, Winston O; Verma, Naveen; Gracias, David H; McAlpine, Michael C
2013-06-12
The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097
16. 3D thermography imaging standardization technique for inflammation diagnosis
Ju, Xiangyang; Nebel, Jean-Christophe; Siebert, J. Paul
2005-01-01
We develop a 3D thermography imaging standardization technique to allow quantitative data analysis. Medical Digital Infrared Thermal Imaging is very sensitive and reliable mean of graphically mapping and display skin surface temperature. It allows doctors to visualise in colour and quantify temperature changes in skin surface. The spectrum of colours indicates both hot and cold responses which may co-exist if the pain associate with an inflammatory focus excites an increase in sympathetic activity. However, due to thermograph provides only qualitative diagnosis information, it has not gained acceptance in the medical and veterinary communities as a necessary or effective tool in inflammation and tumor detection. Here, our technique is based on the combination of visual 3D imaging technique and thermal imaging technique, which maps the 2D thermography images on to 3D anatomical model. Then we rectify the 3D thermogram into a view independent thermogram and conform it a standard shape template. The combination of these imaging facilities allows the generation of combined 3D and thermal data from which thermal signatures can be quantified.
17. LOTT RANCH 3D PROJECT
SciTech Connect
Larry Lawrence; Bruce Miller
2004-09-01
The Lott Ranch 3D seismic prospect located in Garza County, Texas is a project initiated in September of 1991 by the J.M. Huber Corp., a petroleum exploration and production company. By today's standards the 126 square mile project does not seem monumental, however at the time it was conceived it was the most intensive land 3D project ever attempted. Acquisition began in September of 1991 utilizing GEO-SEISMIC, INC., a seismic data contractor. The field parameters were selected by J.M. Huber, and were of a radical design. The recording instruments used were GeoCor IV amplifiers designed by Geosystems Inc., which record the data in signed bit format. It would not have been practical, if not impossible, to have processed the entire raw volume with the tools available at that time. The end result was a dataset that was thought to have little utility due to difficulties in processing the field data. In 1997, Yates Energy Corp. located in Roswell, New Mexico, formed a partnership to further develop the project. Through discussions and meetings with Pinnacle Seismic, it was determined that the original Lott Ranch 3D volume could be vastly improved upon reprocessing. Pinnacle Seismic had shown the viability of improving field-summed signed bit data on smaller 2D and 3D projects. Yates contracted Pinnacle Seismic Ltd. to perform the reprocessing. This project was initiated with high resolution being a priority. Much of the potential resolution was lost through the initial summing of the field data. Modern computers that are now being utilized have tremendous speed and storage capacities that were cost prohibitive when this data was initially processed. Software updates and capabilities offer a variety of quality control and statics resolution, which are pertinent to the Lott Ranch project. The reprocessing effort was very successful. The resulting processed data-set was then interpreted using modern PC-based interpretation and mapping software. Production data, log data
18. 3D RoboMET Characterization
SciTech Connect
Madison, Jonathan D.; Susan, Donald F.; Kilgo, Alice C.
2015-10-01
The goal of this project is to generate 3D microstructural data by destructive and non-destructive means and provide accompanying characterization and quantitative analysis of such data. This work is a continuing part of a larger effort to relate material performance variability to microstructural variability. That larger effort is called “Predicting Performance Margins” or PPM. In conjunction with that overarching initiative, the RoboMET.3D™ is a specific asset of Center 1800 and is an automated serialsectioning system for destructive analysis of microstructure, which is called upon to provide direct customer support to 1800 and non-1800 customers. To that end, data collection, 3d reconstruction and analysis of typical and atypical microstructures have been pursued for the purposes of qualitative and quantitative characterization with a goal toward linking microstructural defects and/or microstructural features with mechanical response. Material systems examined in FY15 include precipitation hardened 17-4 steel, laser-welds of 304L stainless steel, thermal spray coatings of 304L and geological samples of sandstone.
19. 3D Printing of Graphene Aerogels.
PubMed
Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong
2016-04-01
3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction.
20. 3D Printing of Graphene Aerogels.
PubMed
Zhang, Qiangqiang; Zhang, Feng; Medarametla, Sai Pradeep; Li, Hui; Zhou, Chi; Lin, Dong
2016-04-01
3D printing of a graphene aerogel with true 3D overhang structures is highlighted. The aerogel is fabricated by combining drop-on-demand 3D printing and freeze casting. The water-based GO ink is ejected and freeze-cast into designed 3D structures. The lightweight (<10 mg cm(-3) ) 3D printed graphene aerogel presents superelastic and high electrical conduction. PMID:26861680
1. ShowMe3D
SciTech Connect
Sinclair, Michael B
2012-01-05
ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from the displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.
2. 3D Elastic Wavefield Tomography
Guasch, L.; Warner, M.; Stekl, I.; Umpleby, A.; Shah, N.
2010-12-01
Wavefield tomography, or waveform inversion, aims to extract the maximum information from seismic data by matching trace by trace the response of the solid earth to seismic waves using numerical modelling tools. Its first formulation dates from the early 80's, when Albert Tarantola developed a solid theoretical basis that is still used today with little change. Due to computational limitations, the application of the method to 3D problems has been unaffordable until a few years ago, and then only under the acoustic approximation. Although acoustic wavefield tomography is widely used, a complete solution of the seismic inversion problem requires that we account properly for the physics of wave propagation, and so must include elastic effects. We have developed a 3D tomographic wavefield inversion code that incorporates the full elastic wave equation. The bottle neck of the different implementations is the forward modelling algorithm that generates the synthetic data to be compared with the field seismograms as well as the backpropagation of the residuals needed to form the direction update of the model parameters. Furthermore, one or two extra modelling runs are needed in order to calculate the step-length. Our approach uses a FD scheme explicit time-stepping by finite differences that are 4th order in space and 2nd order in time, which is a 3D version of the one developed by Jean Virieux in 1986. We chose the time domain because an explicit time scheme is much less demanding in terms of memory than its frequency domain analogue, although the discussion of wich domain is more efficient still remains open. We calculate the parameter gradients for Vp and Vs by correlating the normal and shear stress wavefields respectively. A straightforward application would lead to the storage of the wavefield at all grid points at each time-step. We tackled this problem using two different approaches. The first one makes better use of resources for small models of dimension equal
3. Conducting Polymer 3D Microelectrodes
PubMed Central
Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi; Castillo-León, Jaime; Emnéus, Jenny; Svendsen, Winnie E.
2010-01-01
Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements. PMID:22163508
4. ShowMe3D
2012-01-05
ShowMe3D is a data visualization graphical user interface specifically designed for use with hyperspectral image obtained from the Hyperspectral Confocal Microscope. The program allows the user to select and display any single image from a three dimensional hyperspectral image stack. By moving a slider control, the user can easily move between images of the stack. The user can zoom into any region of the image. The user can select any pixel or region from themore » displayed image and display the fluorescence spectrum associated with that pixel or region. The user can define up to 3 spectral filters to apply to the hyperspectral image and view the image as it would appear from a filter-based confocal microscope. The user can also obtain statistics such as intensity average and variance from selected regions.« less
5. JAS3D v. 2.4
SciTech Connect
Heinstein, Martin; Blanford, Mark; Stone, Charles; & Key, Samuel
2009-06-29
JAS3D is a three-dimensional finite element program originally designed to solve Lagrangian quasistatic non-linear mechanics problems, and subsequently extended to include both implicit and explicit dynamics. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. Innovative multilevel nonlinear iterative methods are used to solve the equations. A wide variety of material constitutive models are available, and contact interface logic is implemented. Two Lagrangian uniform-strain elements are available: an eighth-node hexahedron for solids and a four-node quadrilateral for shells. Both use hourglass stiffness to control zero-energy modes. In addition, a version of the hexahedron is available with uniform pressure and a deviatoric response scalable from the mean response of the original element up to a fully-integrated response. Bodies under analysis may be loaded by surface pressures and concentrated forces, specified displacements, or body forces from gravity, steady-state transport, or thermal expansion.
6. Supernova Remnant in 3-D
NASA Technical Reports Server (NTRS)
2009-01-01
wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.
The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.
This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.
High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these
7. Imaging and 3D morphological analysis of collagen fibrils.
PubMed
Altendorf, H; Decencière, E; Jeulin, D; De sa Peixoto, P; Deniset-Besseau, A; Angelini, E; Mosser, G; Schanne-Klein, M-C
2012-08-01
The recent booming of multiphoton imaging of collagen fibrils by means of second harmonic generation microscopy generates the need for the development and automation of quantitative methods for image analysis. Standard approaches sequentially analyse two-dimensional (2D) slices to gain knowledge on the spatial arrangement and dimension of the fibrils, whereas the reconstructed three-dimensional (3D) image yields better information about these characteristics. In this work, a 3D analysis method is proposed for second harmonic generation images of collagen fibrils, based on a recently developed 3D fibre quantification method. This analysis uses operators from mathematical morphology. The fibril structure is scanned with a directional distance transform. Inertia moments of the directional distances yield the main fibre orientation, corresponding to the main inertia axis. The collaboration of directional distances and fibre orientation delivers a geometrical estimate of the fibre radius. The results include local maps as well as global distribution of orientation and radius of the fibrils over the 3D image. They also bring a segmentation of the image into foreground and background, as well as a classification of the foreground pixels into the preferred orientations. This accurate determination of the spatial arrangement of the fibrils within a 3D data set will be most relevant in biomedical applications. It brings the possibility to monitor remodelling of collagen tissues upon a variety of injuries and to guide tissues engineering because biomimetic 3D organizations and density are requested for better integration of implants.
8. Formal representation of 3D structural geological models
Wang, Zhangang; Qu, Honggang; Wu, Zixing; Yang, Hongjun; Du, Qunle
2016-05-01
The development and widespread application of geological modeling methods has increased demands for the integration and sharing services of three dimensional (3D) geological data. However, theoretical research in the field of geological information sciences is limited despite the widespread use of Geographic Information Systems (GIS) in geology. In particular, fundamental research on the formal representations and standardized spatial descriptions of 3D structural models is required. This is necessary for accurate understanding and further applications of geological data in 3D space. In this paper, we propose a formal representation method for 3D structural models using the theory of point set topology, which produces a mathematical definition for the major types of geological objects. The spatial relationships between geologic boundaries, structures, and units are explained in detail using the 9-intersection model. Reasonable conditions for describing the topological space of 3D structural models are also provided. The results from this study can be used as potential support for the standardized representation and spatial quality evaluation of 3D structural models, as well as for specific needs related to model-based management, query, and analysis.
9. Supernova Remnant in 3-D
NASA Technical Reports Server (NTRS)
2009-01-01
wavelengths. Since the amount of the wavelength shift is related to the speed of motion, one can determine how fast the debris are moving in either direction. Because Cas A is the result of an explosion, the stellar debris is expanding radially outwards from the explosion center. Using simple geometry, the scientists were able to construct a 3-D model using all of this information. A program called 3-D Slicer modified for astronomical use by the Astronomical Medicine Project at Harvard University in Cambridge, Mass. was used to display and manipulate the 3-D model. Commercial software was then used to create the 3-D fly-through.
The blue filaments defining the blast wave were not mapped using the Doppler effect because they emit a different kind of light synchrotron radiation that does not emit light at discrete wavelengths, but rather in a broad continuum. The blue filaments are only a representation of the actual filaments observed at the blast wave.
This visualization shows that there are two main components to this supernova remnant: a spherical component in the outer parts of the remnant and a flattened (disk-like) component in the inner region. The spherical component consists of the outer layer of the star that exploded, probably made of helium and carbon. These layers drove a spherical blast wave into the diffuse gas surrounding the star. The flattened component that astronomers were unable to map into 3-D prior to these Spitzer observations consists of the inner layers of the star. It is made from various heavier elements, not all shown in the visualization, such as oxygen, neon, silicon, sulphur, argon and iron.
High-velocity plumes, or jets, of this material are shooting out from the explosion in the plane of the disk-like component mentioned above. Plumes of silicon appear in the northeast and southwest, while those of iron are seen in the southeast and north. These jets were already known and Doppler velocity measurements have been made for these
10. 3-D inelastic analysis methods for hot section components (base program). [turbine blades, turbine vanes, and combustor liners
NASA Technical Reports Server (NTRS)
Wilson, R. B.; Bak, M. J.; Nakazawa, S.; Banerjee, P. K.
1984-01-01
A 3-D inelastic analysis methods program consists of a series of computer codes embodying a progression of mathematical models (mechanics of materials, special finite element, boundary element) for streamlined analysis of combustor liners, turbine blades, and turbine vanes. These models address the effects of high temperatures and thermal/mechanical loadings on the local (stress/strain) and global (dynamics, buckling) structural behavior of the three selected components. These models are used to solve 3-D inelastic problems using linear approximations in the sense that stresses/strains and temperatures in generic modeling regions are linear functions of the spatial coordinates, and solution increments for load, temperature and/or time are extrapolated linearly from previous information. Three linear formulation computer codes, referred to as MOMM (Mechanics of Materials Model), MHOST (MARC-Hot Section Technology), and BEST (Boundary Element Stress Technology), were developed and are described.
11. 3D multiplexed immunoplasmonics microscopy
Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel
2016-07-01
Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed
12. 3D multiplexed immunoplasmonics microscopy.
PubMed
Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel
2016-07-21
Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K(+) channel subunit KV1.1) on human cancer CD44(+) EGFR(+) KV1.1(+) MDA-MB-231 cells and reference CD44(-) EGFR(-) KV1.1(+) 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third
13. NIF Ignition Target 3D Point Design
SciTech Connect
Jones, O; Marinak, M; Milovich, J; Callahan, D
2008-11-05
We have developed an input file for running 3D NIF hohlraums that is optimized such that it can be run in 1-2 days on parallel computers. We have incorporated increasing levels of automation into the 3D input file: (1) Configuration controlled input files; (2) Common file for 2D and 3D, different types of capsules (symcap, etc.); and (3) Can obtain target dimensions, laser pulse, and diagnostics settings automatically from NIF Campaign Management Tool. Using 3D Hydra calculations to investigate different problems: (1) Intrinsic 3D asymmetry; (2) Tolerance to nonideal 3D effects (e.g. laser power balance, pointing errors); and (3) Synthetic diagnostics.
14. An optimal performance control scheme for a 3D crane
2016-01-01
This paper presents an optimal performance control scheme for control of a three dimensional (3D) crane system including a Zero Vibration shaper which considers two control objectives concurrently. The control objectives are fast and accurate positioning of a trolley and minimum sway of a payload. A complete mathematical model of a lab-scaled 3D crane is simulated in Simulink. With a specific cost function the proposed controller is designed to cater both control objectives similar to a skilled operator. Simulation and experimental studies on a 3D crane show that the proposed controller has better performance as compared to a sequentially tuned PID-PID anti swing controller. The controller provides better position response with satisfactory payload sway in both rail and trolley responses. Experiments with different payloads and cable lengths show that the proposed controller is robust to changes in payload with satisfactory responses.
15. 3D braid scaffolds for regeneration of articular cartilage.
PubMed
Ahn, Hyunchul; Kim, Kyoung Ju; Park, Sook Young; Huh, Jeong Eun; Kim, Hyun Jeong; Yu, Woong-Ryeol
2014-06-01
Regenerating articular cartilage in vivo from cultured chondrocytes requires that the cells be cultured and implanted within a biocompatible, biodegradable scaffold. Such scaffolds must be mechanically stable; otherwise chondrocytes would not be supported and patients would experience severe pain. Here we report a new 3D braid scaffold that matches the anisotropic (gradient) mechanical properties of natural articular cartilage and is permissive to cell cultivation. To design an optimal structure, the scaffold unit cell was mathematically modeled and imported into finite element analysis. Based on this analysis, a 3D braid structure with gradient axial yarn distribution was designed and manufactured using a custom-built braiding machine. The mechanical properties of the 3D braid scaffold were evaluated and compared with simulated results, demonstrating that a multi-scale approach consisting of unit cell modeling and continuum analysis facilitates design of scaffolds that meet the requirements for mechanical compatibility with tissues. PMID:24556323
16. 3D Kitaev spin liquids
Hermanns, Maria
The Kitaev honeycomb model has become one of the archetypal spin models exhibiting topological phases of matter, where the magnetic moments fractionalize into Majorana fermions interacting with a Z2 gauge field. In this talk, we discuss generalizations of this model to three-dimensional lattice structures. Our main focus is the metallic state that the emergent Majorana fermions form. In particular, we discuss the relation of the nature of this Majorana metal to the details of the underlying lattice structure. Besides (almost) conventional metals with a Majorana Fermi surface, one also finds various realizations of Dirac semi-metals, where the gapless modes form Fermi lines or even Weyl nodes. We introduce a general classification of these gapless quantum spin liquids using projective symmetry analysis. Furthermore, we briefly outline why these Majorana metals in 3D Kitaev systems provide an even richer variety of Dirac and Weyl phases than possible for electronic matter and comment on possible experimental signatures. Work done in collaboration with Kevin O'Brien and Simon Trebst.
17. Locomotive wheel 3D reconstruction
Guan, Xin; Luo, Zhisheng; Gao, Xiaorong; Wu, Jianle
2010-08-01
In the article, a system, which is used to reconstruct locomotive wheels, is described, helping workers detect the condition of a wheel through a direct view. The system consists of a line laser, a 2D camera, and a computer. We use 2D camera to capture the line-laser light reflected by the object, a wheel, and then compute the final coordinates of the structured light. Finally, using Matlab programming language, we transform the coordinate of points to a smooth surface and illustrate the 3D view of the wheel. The article also proposes the system structure, processing steps and methods, and sets up an experimental platform to verify the design proposal. We verify the feasibility of the whole process, and analyze the results comparing to standard date. The test results show that this system can work well, and has a high accuracy on the reconstruction. And because there is still no such application working in railway industries, so that it has practical value in railway inspection system.
18. 3D ultrafast laser scanner
Mahjoubfar, A.; Goda, K.; Wang, C.; Fard, A.; Adam, J.; Gossett, D. R.; Ayazi, A.; Sollier, E.; Malik, O.; Chen, E.; Liu, Y.; Brown, R.; Sarkhosh, N.; Di Carlo, D.; Jalali, B.
2013-03-01
Laser scanners are essential for scientific research, manufacturing, defense, and medical practice. Unfortunately, often times the speed of conventional laser scanners (e.g., galvanometric mirrors and acousto-optic deflectors) falls short for many applications, resulting in motion blur and failure to capture fast transient information. Here, we present a novel type of laser scanner that offers roughly three orders of magnitude higher scan rates than conventional methods. Our laser scanner, which we refer to as the hybrid dispersion laser scanner, performs inertia-free laser scanning by dispersing a train of broadband pulses both temporally and spatially. More specifically, each broadband pulse is temporally processed by time stretch dispersive Fourier transform and further dispersed into space by one or more diffractive elements such as prisms and gratings. As a proof-of-principle demonstration, we perform 1D line scans at a record high scan rate of 91 MHz and 2D raster scans and 3D volumetric scans at an unprecedented scan rate of 105 kHz. The method holds promise for a broad range of scientific, industrial, and biomedical applications. To show the utility of our method, we demonstrate imaging, nanometer-resolved surface vibrometry, and high-precision flow cytometry with real-time throughput that conventional laser scanners cannot offer due to their low scan rates.
19. 3D multiplexed immunoplasmonics microscopy
Bergeron, Éric; Patskovsky, Sergiy; Rioux, David; Meunier, Michel
2016-07-01
Selective labelling, identification and spatial distribution of cell surface biomarkers can provide important clinical information, such as distinction between healthy and diseased cells, evolution of a disease and selection of the optimal patient-specific treatment. Immunofluorescence is the gold standard for efficient detection of biomarkers expressed by cells. However, antibodies (Abs) conjugated to fluorescent dyes remain limited by their photobleaching, high sensitivity to the environment, low light intensity, and wide absorption and emission spectra. Immunoplasmonics is a novel microscopy method based on the visualization of Abs-functionalized plasmonic nanoparticles (fNPs) targeting cell surface biomarkers. Tunable fNPs should provide higher multiplexing capacity than immunofluorescence since NPs are photostable over time, strongly scatter light at their plasmon peak wavelengths and can be easily functionalized. In this article, we experimentally demonstrate accurate multiplexed detection based on the immunoplasmonics approach. First, we achieve the selective labelling of three targeted cell surface biomarkers (cluster of differentiation 44 (CD44), epidermal growth factor receptor (EGFR) and voltage-gated K+ channel subunit KV1.1) on human cancer CD44+ EGFR+ KV1.1+ MDA-MB-231 cells and reference CD44- EGFR- KV1.1+ 661W cells. The labelling efficiency with three stable specific immunoplasmonics labels (functionalized silver nanospheres (CD44-AgNSs), gold (Au) NSs (EGFR-AuNSs) and Au nanorods (KV1.1-AuNRs)) detected by reflected light microscopy (RLM) is similar to the one with immunofluorescence. Second, we introduce an improved method for 3D localization and spectral identification of fNPs based on fast z-scanning by RLM with three spectral filters corresponding to the plasmon peak wavelengths of the immunoplasmonics labels in the cellular environment (500 nm for 80 nm AgNSs, 580 nm for 100 nm AuNSs and 700 nm for 40 nm × 92 nm AuNRs). Third, the developed
20. Crowdsourcing Based 3d Modeling
Somogyi, A.; Barsi, A.; Molnar, B.; Lovas, T.
2016-06-01
Web-based photo albums that support organizing and viewing the users' images are widely used. These services provide a convenient solution for storing, editing and sharing images. In many cases, the users attach geotags to the images in order to enable using them e.g. in location based applications on social networks. Our paper discusses a procedure that collects open access images from a site frequently visited by tourists. Geotagged pictures showing the image of a sight or tourist attraction are selected and processed in photogrammetric processing software that produces the 3D model of the captured object. For the particular investigation we selected three attractions in Budapest. To assess the geometrical accuracy, we used laser scanner and DSLR as well as smart phone photography to derive reference values to enable verifying the spatial model obtained from the web-album images. The investigation shows how detailed and accurate models could be derived applying photogrammetric processing software, simply by using images of the community, without visiting the site.
1. 3D Winding Number: Theory and Application to Medical Imaging
PubMed Central
Becciu, Alessandro; Fuster, Andrea; Pottek, Mark; van den Heuvel, Bart; ter Haar Romeny, Bart; van Assen, Hans
2011-01-01
We develop a new formulation, mathematically elegant, to detect critical points of 3D scalar images. It is based on a topological number, which is the generalization to three dimensions of the 2D winding number. We illustrate our method by considering three different biomedical applications, namely, detection and counting of ovarian follicles and neuronal cells and estimation of cardiac motion from tagged MR images. Qualitative and quantitative evaluation emphasizes the reliability of the results. PMID:21317978
2. Imaging hypoxia using 3D photoacoustic spectroscopy
Stantz, Keith M.
2010-02-01
Purpose: The objective is to develop a multivariate in vivo hemodynamic model of tissue oxygenation (MiHMO2) based on 3D photoacoustic spectroscopy. Introduction: Low oxygen levels, or hypoxia, deprives cancer cells of oxygen and confers resistance to irradiation, some chemotherapeutic drugs, and oxygen-dependent therapies (phototherapy) leading to treatment failure and poor disease-free and overall survival. For example, clinical studies of patients with breast carcinomas, cervical cancer, and head and neck carcinomas (HNC) are more likely to suffer local reoccurrence and metastasis if their tumors are hypoxic. A novel method to non invasively measure tumor hypoxia, identify its type, and monitor its heterogeneity is devised by measuring tumor hemodynamics, MiHMO2. Material and Methods: Simulations are performed to compare tumor pO2 levels and hypoxia based on physiology - perfusion, fractional plasma volume, fractional cellular volume - and its hemoglobin status - oxygen saturation and hemoglobin concentration - based on in vivo measurements of breast, prostate, and ovarian tumors. Simulations of MiHMO2 are performed to assess the influence of scanner resolutions and different mathematic models of oxygen delivery. Results: Sensitivity of pO2 and hypoxic fraction to photoacoustic scanner resolution and dependencies on model complexity will be presented using hemodynamic parameters for different tumors. Conclusions: Photoacoustic CT spectroscopy provides a unique ability to monitor hemodynamic and cellular physiology in tissue, which can be used to longitudinally monitor tumor oxygenation and its response to anti-angiogenic therapies.
3. Forward ramp in 3D
NASA Technical Reports Server (NTRS)
1997-01-01
Mars Pathfinder's forward rover ramp can be seen successfully unfurled in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This ramp was not used for the deployment of the microrover Sojourner, which occurred at the end of Sol 2. When this image was taken, Sojourner was still latched to one of the lander's petals, waiting for the command sequence that would execute its descent off of the lander's petal.
The image helped Pathfinder scientists determine whether to deploy the rover using the forward or backward ramps and the nature of the first rover traverse. The metallic object at the lower left of the image is the lander's low-gain antenna. The square at the end of the ramp is one of the spacecraft's magnetic targets. Dust that accumulates on the magnetic targets will later be examined by Sojourner's Alpha Proton X-Ray Spectrometer instrument for chemical analysis. At right, a lander petal is visible.
The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.' It stands 1.8 meters above the Martian surface, and has a resolution of two millimeters at a range of two meters.
Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.
Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right
4. 3D grain boundary migration
Becker, J. K.; Bons, P. D.
2009-04-01
Microstructures of rocks play an important role in determining rheological properties and help to reveal the processes that lead to their formation. Some of these processes change the microstructure significantly and may thus have the opposite effect in obliterating any fabrics indicative of the previous history of the rocks. One of these processes is grain boundary migration (GBM). During static recrystallisation, GBM may produce a foam texture that completely overprints a pre-existing grain boundary network and GBM actively influences the rheology of a rock, via its influence on grain size and lattice defect concentration. We here present a new numerical simulation software that is capable of simulating a whole range of processes on the grain scale (it is not limited to grain boundary migration). The software is polyhedron-based, meaning that each grain (or phase) is represented by a polyhedron that has discrete boundaries. The boundary (the shell) of the polyhedron is defined by a set of facets which in turn is defined by a set of vertices. Each structural entity (polyhedron, facets and vertices) can have an unlimited number of parameters (depending on the process to be modeled) such as surface energy, concentration, etc. which can be used to calculate changes of the microstructre. We use the processes of grain boundary migration of a "regular" and a partially molten rock to demonstrate the software. Since this software is 3D, the formation of melt networks in a partially molten rock can also be studied. The interconnected melt network is of fundamental importance for melt segregation and migration in the crust and mantle and can help to understand the core-mantle differentiation of large terrestrial planets.
5. Research and Teaching: Methods for Creating and Evaluating 3D Tactile Images to Teach STEM Courses to the Visually Impaired
ERIC Educational Resources Information Center
Hasper, Eric; Windhorst, Rogier; Hedgpeth, Terri; Van Tuyl, Leanne; Gonzales, Ashleigh; Martinez, Britta; Yu, Hongyu; Farkas, Zolton; Baluch, Debra P.
2015-01-01
Project 3D IMAGINE or 3D Image Arrays to Graphically Implement New Education is a pilot study that researches the effectiveness of incorporating 3D tactile images, which are critical for learning science, technology, engineering, and mathematics, into entry-level lab courses. The focus of this project is to increase the participation and…
6. Advanced methods for 3-D inelastic structural analysis for hot engine structures
NASA Technical Reports Server (NTRS)
Chamis, C. C.
1989-01-01
Three-dimensional Inelastic Analysis Methods are described. These methods were incorporated into a series of new computer codes embodying a progression of mathematical models (mechanics of materials, specialty finite element, boundary element) for streamlined analysis of hot engine structures such as: (1) combustor liners, (2) turbine blades, and (3) turbine vanes. These models address the effects of high temperatures and thermal/mechanical loadings on the local (stress/strain) and global (displacements, frequencies, amplitudes, buckling) structural behavior of the three respective components. The methods and the three computer codes, referred to as MOMM (Mechanics Of Materials Model), MHOST (MARC-Hot Section Technology), and BEST3D (Boundary Element Stress Technology), have been developed and are briefly described.
7. 3D Printing and Its Urologic Applications
PubMed Central
Soliman, Youssef; Feibus, Allison H; Baum, Neil
2015-01-01
3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology. PMID:26028997
8. Imaging a Sustainable Future in 3D
Schuhr, W.; Lee, J. D.; Kanngieser, E.
2012-07-01
It is the intention of this paper, to contribute to a sustainable future by providing objective object information based on 3D photography as well as promoting 3D photography not only for scientists, but also for amateurs. Due to the presentation of this article by CIPA Task Group 3 on "3D Photographs in Cultural Heritage", the presented samples are masterpieces of historic as well as of current 3D photography concentrating on cultural heritage. In addition to a report on exemplarily access to international archives of 3D photographs, samples for new 3D photographs taken with modern 3D cameras, as well as by means of a ground based high resolution XLITE staff camera and also 3D photographs taken from a captive balloon and the use of civil drone platforms are dealt with. To advise on optimum suited 3D methodology, as well as to catch new trends in 3D, an updated synoptic overview of the 3D visualization technology, even claiming completeness, has been carried out as a result of a systematic survey. In this respect, e.g., today's lasered crystals might be "early bird" products in 3D, which, due to lack in resolution, contrast and color, remember to the stage of the invention of photography.
9. 3D Printing and Its Urologic Applications.
PubMed
Soliman, Youssef; Feibus, Allison H; Baum, Neil
2015-01-01
3D printing is the development of 3D objects via an additive process in which successive layers of material are applied under computer control. This article discusses 3D printing, with an emphasis on its historical context and its potential use in the field of urology.
10. Beowulf 3D: a case study
Engle, Rob
2008-02-01
This paper discusses the creative and technical challenges encountered during the production of "Beowulf 3D," director Robert Zemeckis' adaptation of the Old English epic poem and the first film to be simultaneously released in IMAX 3D and digital 3D formats.
11. Teaching Geography with 3-D Visualization Technology
ERIC Educational Resources Information Center
Anthamatten, Peter; Ziegler, Susy S.
2006-01-01
Technology that helps students view images in three dimensions (3-D) can support a broad range of learning styles. "Geo-Wall systems" are visualization tools that allow scientists, teachers, and students to project stereographic images and view them in 3-D. We developed and presented 3-D visualization exercises in several undergraduate courses.…
12. Expanding Geometry Understanding with 3D Printing
ERIC Educational Resources Information Center
Cochran, Jill A.; Cochran, Zane; Laney, Kendra; Dean, Mandi
2016-01-01
With the rise of personal desktop 3D printing, a wide spectrum of educational opportunities has become available for educators to leverage this technology in their classrooms. Until recently, the ability to create physical 3D models was well beyond the scope, skill, and budget of many schools. However, since desktop 3D printers have become readily…
13. 3D Elastic Seismic Wave Propagation Code
1998-09-23
E3D is capable of simulating seismic wave propagation in a 3D heterogeneous earth. Seismic waves are initiated by earthquake, explosive, and/or other sources. These waves propagate through a 3D geologic model, and are simulated as synthetic seismograms or other graphical output.
14. 3D Flow Visualization Using Texture Advection
NASA Technical Reports Server (NTRS)
Kao, David; Zhang, Bing; Kim, Kwansik; Pang, Alex; Moran, Pat (Technical Monitor)
2001-01-01
Texture advection is an effective tool for animating and investigating 2D flows. In this paper, we discuss how this technique can be extended to 3D flows. In particular, we examine the use of 3D and 4D textures on 3D synthetic and computational fluid dynamics flow fields.
15. Extra dimensions: 3D and time in PDF documentation
Graf, N. A.
2011-01-01
16. Hough transform-based 3D mesh retrieval
Zaharia, Titus; Preteux, Francoise J.
2001-11-01
This papre addresses the issue of 3D mesh indexation by using shape descriptors (SDs) under constraints of geometric and topological invariance. A new shape descriptor, the Optimized 3D Hough Transform Descriptor (O3HTD) is here proposed. Intrinsically topologically stable, the O3DHTD is not invariant to geometric transformations. Nevertheless, we show mathematically how the O3DHTD can be optimally associated (in terms of compactness of representation and computational complexity) with a spatial alignment procedure which leads to a geometric invariant behavior. Experimental results have been carried out upon the MPEG-7 3D model database consisting of about 1300 meshes in VRML 2.0 format. Objective retrieval results, based upon the definition of a categorized ground truth subset, are reported in terms of Bull Eye Percentage (BEP) score and compared to those obtained by applying the MPEg-7 3D SD. It is shown that the O3DHTD outperforms the MPEg-7 3D SD of up to 28%.
17. Extra Dimensions: 3D and Time in PDF Documentation
SciTech Connect
Graf, N.A.; /SLAC
2012-04-11
NASA Technical Reports Server (NTRS)
2000-01-01
19. Quality optimization of thermally sprayed coatings produced by the JP-5000 (HVOF) gun using mathematical modeling
NASA Technical Reports Server (NTRS)
Tawfik, Hazem
1994-01-01
Currently, thermal barrier coatings (TBC) of gas-turbine blades and similar applications have centered around the use of zirconia as a protective coating for high thermal applications. The advantages of zirconia include low thermal conductivity and good thermal shock resistance. Thermally sprayed tungsten carbide hardface coatings are used for a wide range of applications spanning both the aerospace and other industrial markets. Major aircraft engine manufacturers and repair facilities use hardface coatings for original engine manufacture (OEM), as well as in the overhaul of critical engine components. The principle function of these coatings is to resist severe wear environments for such wear mechanisms as abrasion, adhesion, fretting, and erosion. The (JP-5000) thermal spray gun is the most advanced in the High Velocity Oxygen Fuel (HVOF) systems. Recently, it has received considerable attention because of its relative low cost and its production of quality coatings that challenge the very successful but yet very expensive Vacuum Plasma Spraying (VPS) system. The quality of thermal spray coatings is enhanced as porosity, oxidation, residual stress, and surface roughness are reduced or minimized. Higher densification, interfacial bonding strength, hardness and wear resistance of coating are desirable features for quality improvement.
20. Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion
Handy Turner, Tara
2010-02-01
From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.
1. RELAP5-3D User Problems
SciTech Connect
Riemke, Richard Allan
2002-09-01
The Reactor Excursion and Leak Analysis Program with 3D capability1 (RELAP5-3D) is a reactor system analysis code that has been developed at the Idaho National Engineering and Environmental Laboratory (INEEL) for the U. S. Department of Energy (DOE). The 3D capability in RELAP5-3D includes 3D hydrodynamics2 and 3D neutron kinetics3,4. Assessment, verification, and validation of the 3D capability in RELAP5-3D is discussed in the literature5,6,7,8,9,10. Additional assessment, verification, and validation of the 3D capability of RELAP5-3D will be presented in other papers in this users seminar. As with any software, user problems occur. User problems usually fall into the categories of input processing failure, code execution failure, restart/renodalization failure, unphysical result, and installation. This presentation will discuss some of the more generic user problems that have been reported on RELAP5-3D as well as their resolution.
2. Mathematical modeling and numerical analysis of thermal distribution in arch dams considering solar radiation effect.
PubMed
Mirzabozorg, H; Hariri-Ardebili, M A; Shirkhan, M; Seyed-Kolbadi, S M
2014-01-01
The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams.
3. Mathematical Modeling and Numerical Analysis of Thermal Distribution in Arch Dams considering Solar Radiation Effect
PubMed Central
Mirzabozorg, H.; Hariri-Ardebili, M. A.; Shirkhan, M.; Seyed-Kolbadi, S. M.
2014-01-01
The effect of solar radiation on thermal distribution in thin high arch dams is investigated. The differential equation governing thermal behavior of mass concrete in three-dimensional space is solved applying appropriate boundary conditions. Solar radiation is implemented considering the dam face direction relative to the sun, the slop relative to horizon, the region cloud cover, and the surrounding topography. It has been observed that solar radiation changes the surface temperature drastically and leads to nonuniform temperature distribution. Solar radiation effects should be considered in thermal transient analysis of thin arch dams. PMID:24695817
4. 3D laptop for defense applications
Edmondson, Richard; Chenault, David
2012-06-01
Polaris Sensor Technologies has developed numerous 3D display systems using a US Army patented approach. These displays have been developed as prototypes for handheld controllers for robotic systems and closed hatch driving, and as part of a TALON robot upgrade for 3D vision, providing depth perception for the operator for improved manipulation and hazard avoidance. In this paper we discuss the prototype rugged 3D laptop computer and its applications to defense missions. The prototype 3D laptop combines full temporal and spatial resolution display with the rugged Amrel laptop computer. The display is viewed through protective passive polarized eyewear, and allows combined 2D and 3D content. Uses include robot tele-operation with live 3D video or synthetically rendered scenery, mission planning and rehearsal, enhanced 3D data interpretation, and simulation.
5. Gis-Based Smart Cartography Using 3d Modeling
Malinverni, E. S.; Tassetti, A. N.
2013-08-01
3D City Models have evolved to be important tools for urban decision processes and information systems, especially in planning, simulation, analysis, documentation and heritage management. On the other hand existing and in use numerical cartography is often not suitable to be used in GIS because not geometrically and topologically correctly structured. The research aim is to 3D structure and organize a numeric cartography for GIS and turn it into CityGML standardized features. The work is framed around a first phase of methodological analysis aimed to underline which existing standard (like ISO and OGC rules) can be used to improve the quality requirement of a cartographic structure. Subsequently, from this technical specifics, it has been investigated the translation in formal contents, using an owner interchange software (SketchUp), to support some guide lines implementations to generate a GIS3D structured in GML3. It has been therefore predisposed a test three-dimensional numerical cartography (scale 1:500, generated from range data captured by 3D laser scanner), tested on its quality according to the previous standard and edited when and where necessary. Cad files and shapefiles are converted into a final 3D model (Google SketchUp model) and then exported into a 3D city model (CityGML LoD1/LoD2). The GIS3D structure has been managed in a GIS environment to run further spatial analysis and energy performance estimate, not achievable in a 2D environment. In particular geometrical building parameters (footprint, volume etc.) are computed and building envelop thermal characteristics are derived from. Lastly, a simulation is carried out to deal with asbestos and home renovating charges and show how the built 3D city model can support municipal managers with risk diagnosis of the present situation and development of strategies for a sustainable redevelop.
6. Three dimensional thermal pollution models. Volume 1: Review of mathematical formulations. [waste heat discharge from power plants and effects on ecosystems
NASA Technical Reports Server (NTRS)
Lee, S. S.; Sengupta, S.
1978-01-01
A mathematical model package for thermal pollution analyses and prediction is presented. These models, intended as user's manuals, are three dimensional and time dependent using the primitive equation approach. Although they have sufficient generality for application at sites with diverse topographical features; they also present specific instructions regarding data preparation for program execution and sample problems. The mathematical formulation of these models is presented including assumptions, approximations, governing equations, boundary and initial conditions, numerical method of solution, and same results.
7. Application of 3D printing technology in aerodynamic study
Olasek, K.; Wiklak, P.
2014-08-01
3D printing, as an additive process, offers much more than traditional machining techniques in terms of achievable complexity of a model shape. That fact was a motivation to adapt discussed technology as a method for creating objects purposed for aerodynamic testing. The following paper provides an overview of various 3D printing techniques. Four models of a standard NACA0018 aerofoil were manufactured in different materials and methods: MultiJet Modelling (MJM), Selective Laser Sintering (SLS) and Fused Deposition Modeling (FDM). Various parameters of the models have been included in the analysis: surface roughness, strength, details quality, surface imperfections and irregularities as well as thermal properties.
8. RELAP5-3D Code Validation for RBMK Phenomena
SciTech Connect
Fisher, James Ebberly
1999-09-01
The RELAP5-3D thermal-hydraulic code was assessed against Japanese Safety Experiment Loop (SEL) and Heat Transfer Loop (HTL) tests. These tests were chosen because the phenomena present are applicable to analyses of Russian RBMK reactor designs. The assessment cases included parallel channel flow fluctuation tests at reduced and normal water levels, a channel inlet pipe rupture test, and a high power, density wave oscillation test. The results showed that RELAP5-3D has the capability to adequately represent these RBMK-related phenomena.
9. RELAP5-3D code validation for RBMK phenomena
SciTech Connect
Fisher, J.E.
1999-09-01
The RELAP5-3D thermal-hydraulic code was assessed against Japanese Safety Experiment Loop (SEL) and Heat Transfer Loop (HTL) tests. These tests were chosen because the phenomena present are applicable to analyses of Russian RBMK reactor designs. The assessment cases included parallel channel flow fluctuation tests at reduced and normal water levels, a channel inlet pipe rupture test, and a high power, density wave oscillation test. The results showed that RELAP5-3D has the capability to adequately represent these RBMK-related phenomena.
10. Mathematical modeling of temperature mapping over skin surface and its implementation in thermal disease diagnostics.
PubMed
Deng, Zhong-Shan; Liu, Jing
2004-09-01
In non-invasive thermal diagnostics, accurate correlations between the thermal image on skin surface and interior human pathophysiology are often desired, which require general solutions for the bioheat equation. In this study, the Monte Carlo method was implemented to solve the transient three-dimensional bio-heat transfer problem with non-linear boundary conditions (simultaneously with convection, radiation and evaporation) and space-dependent thermal physiological parameters. Detailed computations indicated that the thermal states of biological bodies, reflecting physiological conditions, could be correlated to the temperature or heat flux mapping recorded at the skin surface. The effect of the skin emissivity and humidity, the convective heat transfer coefficient, the relative humidity and temperature of the surrounding air, the metabolic rate and blood perfusion rate in the tumor, and the tumor size and number on the sensitivity of thermography are comprehensively investigated. Moreover, several thermal criteria for disease diagnostic were proposed based on statistical principles. Implementations of this study for the clinical thermal diagnostics are discussed.
11. Reconfigurable 3D plasmonic metamolecules
Kuzyk, Anton; Schreiber, Robert; Zhang, Hui; Govorov, Alexander O.; Liedl, Tim; Liu, Na
2014-09-01
A reconfigurable plasmonic nanosystem combines an active plasmonic structure with a regulated physical or chemical control input. There have been considerable efforts on integration of plasmonic nanostructures with active platforms using top-down techniques. The active media include phase-transition materials, graphene, liquid crystals and carrier-modulated semiconductors, which can respond to thermal, electrical and optical stimuli. However, these plasmonic nanostructures are often restricted to two-dimensional substrates, showing desired optical response only along specific excitation directions. Alternatively, bottom-up techniques offer a new pathway to impart reconfigurability and functionality to passive systems. In particular, DNA has proven to be one of the most versatile and robust building blocks for construction of complex three-dimensional architectures with high fidelity. Here we show the creation of reconfigurable three-dimensional plasmonic metamolecules, which execute DNA-regulated conformational changes at the nanoscale. DNA serves as both a construction material to organize plasmonic nanoparticles in three dimensions, as well as fuel for driving the metamolecules to distinct conformational states. Simultaneously, the three-dimensional plasmonic metamolecules can work as optical reporters, which transduce their conformational changes in situ into circular dichroism changes in the visible wavelength range.
12. Reconfigurable 3D plasmonic metamolecules.
PubMed
Kuzyk, Anton; Schreiber, Robert; Zhang, Hui; Govorov, Alexander O; Liedl, Tim; Liu, Na
2014-09-01
A reconfigurable plasmonic nanosystem combines an active plasmonic structure with a regulated physical or chemical control input. There have been considerable efforts on integration of plasmonic nanostructures with active platforms using top-down techniques. The active media include phase-transition materials, graphene, liquid crystals and carrier-modulated semiconductors, which can respond to thermal, electrical and optical stimuli. However, these plasmonic nanostructures are often restricted to two-dimensional substrates, showing desired optical response only along specific excitation directions. Alternatively, bottom-up techniques offer a new pathway to impart reconfigurability and functionality to passive systems. In particular, DNA has proven to be one of the most versatile and robust building blocks for construction of complex three-dimensional architectures with high fidelity. Here we show the creation of reconfigurable three-dimensional plasmonic metamolecules, which execute DNA-regulated conformational changes at the nanoscale. DNA serves as both a construction material to organize plasmonic nanoparticles in three dimensions, as well as fuel for driving the metamolecules to distinct conformational states. Simultaneously, the three-dimensional plasmonic metamolecules can work as optical reporters, which transduce their conformational changes in situ into circular dichroism changes in the visible wavelength range.
13. 3-D Technology Approaches for Biological Ecologies
Liu, Liyu; Austin, Robert; U. S-China Physical-Oncology Sciences Alliance (PS-OA) Team
Constructing three dimensional (3-D) landscapes is an inevitable issue in deep study of biological ecologies, because in whatever scales in nature, all of the ecosystems are composed by complex 3-D environments and biological behaviors. Just imagine if a 3-D technology could help complex ecosystems be built easily and mimic in vivo microenvironment realistically with flexible environmental controls, it will be a fantastic and powerful thrust to assist researchers for explorations. For years, we have been utilizing and developing different technologies for constructing 3-D micro landscapes for biophysics studies in in vitro. Here, I will review our past efforts, including probing cancer cell invasiveness with 3-D silicon based Tepuis, constructing 3-D microenvironment for cell invasion and metastasis through polydimethylsiloxane (PDMS) soft lithography, as well as explorations of optimized stenting positions for coronary bifurcation disease with 3-D wax printing and the latest home designed 3-D bio-printer. Although 3-D technologies is currently considered not mature enough for arbitrary 3-D micro-ecological models with easy design and fabrication, I hope through my talk, the audiences will be able to sense its significance and predictable breakthroughs in the near future. This work was supported by the State Key Development Program for Basic Research of China (Grant No. 2013CB837200), the National Natural Science Foundation of China (Grant No. 11474345) and the Beijing Natural Science Foundation (Grant No. 7154221).
14. Automatic 3D video format detection
Zhang, Tao; Wang, Zhe; Zhai, Jiefu; Doyen, Didier
2011-03-01
Many 3D formats exist and will probably co-exist for a long time even if 3D standards are today under definition. The support for multiple 3D formats will be important for bringing 3D into home. In this paper, we propose a novel and effective method to detect whether a video is a 3D video or not, and to further identify the exact 3D format. First, we present how to detect those 3D formats that encode a pair of stereo images into a single image. The proposed method detects features and establishes correspondences between features in the left and right view images, and applies the statistics from the distribution of the positional differences between corresponding features to detect the existence of a 3D format and to identify the format. Second, we present how to detect the frame sequential 3D format. In the frame sequential 3D format, the feature points are oscillating from frame to frame. Similarly, the proposed method tracks feature points over consecutive frames, computes the positional differences between features, and makes a detection decision based on whether the features are oscillating. Experiments show the effectiveness of our method.
15. RT3D tutorials for GMS users
SciTech Connect
Clement, T.P.; Jones, N.L.
1998-02-01
RT3D (Reactive Transport in 3-Dimensions) is a computer code that solves coupled partial differential equations that describe reactive-flow and transport of multiple mobile and/or immobile species in a three dimensional saturated porous media. RT3D was developed from the single-species transport code, MT3D (DoD-1.5, 1997 version). As with MT3D, RT3D also uses the USGS groundwater flow model MODFLOW for computing spatial and temporal variations in groundwater head distribution. This report presents a set of tutorial problems that are designed to illustrate how RT3D simulations can be performed within the Department of Defense Groundwater Modeling System (GMS). GMS serves as a pre- and post-processing interface for RT3D. GMS can be used to define all the input files needed by RT3D code, and later the code can be launched from within GMS and run as a separate application. Once the RT3D simulation is completed, the solution can be imported to GMS for graphical post-processing. RT3D v1.0 supports several reaction packages that can be used for simulating different types of reactive contaminants. Each of the tutorials, described below, provides training on a different RT3D reaction package. Each reaction package has different input requirements, and the tutorials are designed to describe these differences. Furthermore, the tutorials illustrate the various options available in GMS for graphical post-processing of RT3D results. Users are strongly encouraged to complete the tutorials before attempting to use RT3D and GMS on a routine basis.
16. 3D View of Death Valley, California
NASA Technical Reports Server (NTRS)
2000-01-01
This 3-D perspective view looking north over Death Valley, California, was produced by draping ASTER nighttime thermal infrared data over topographic data from the US Geological Survey. The ASTER data were acquired April 7, 2000 with the multi-spectral thermal infrared channels, and cover an area of 60 by 80 km (37 by 50 miles). Bands 13, 12, and 10 are displayed in red, green and blue respectively. The data have been computer enhanced to exaggerate the color variations that highlight differences in types of surface materials. Salt deposits on the floor of Death Valley appear in shades of yellow, green, purple, and pink, indicating presence of carbonate, sulfate, and chloride minerals. The Panamint Mtns. to the west, and the Black Mtns. to the east, are made up of sedimentary limestones, sandstones, shales, and metamorphic rocks. The bright red areas are dominated by the mineral quartz, such as is found in sandstones; green areas are limestones. In the lower center part of the image is Badwater, the lowest point in North America.
Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, Calif., is the U.S. Science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.
The broad spectral coverage and high spectral resolution of ASTER
17. JAS3D v. 2.4
2009-06-29
JAS3D is a three-dimensional finite element program originally designed to solve Lagrangian quasistatic non-linear mechanics problems, and subsequently extended to include both implicit and explicit dynamics. A set of continuum equations describes the nonlinear mechanics involving large rotation and strain. Innovative multilevel nonlinear iterative methods are used to solve the equations. A wide variety of material constitutive models are available, and contact interface logic is implemented. Two Lagrangian uniform-strain elements are available: an eighth-node hexahedronmore » for solids and a four-node quadrilateral for shells. Both use hourglass stiffness to control zero-energy modes. In addition, a version of the hexahedron is available with uniform pressure and a deviatoric response scalable from the mean response of the original element up to a fully-integrated response. Bodies under analysis may be loaded by surface pressures and concentrated forces, specified displacements, or body forces from gravity, steady-state transport, or thermal expansion.« less
18. A thermal analysis of a spirally wound battery using a simple mathematical model
SciTech Connect
Evans, T.I.; White, R.E. . Dept. of Chemical Engineering)
1989-08-01
A two-dimensional thermal model for spirally wound batteries has been developed. The governing equation of the model is the energy balance. Convective and insulated boundary conditions are used, and the equations are solved using a finite element code called TOPAZ2D. The finite element mesh is generated using a preprocessor to TOPAZ2D called MAZE. The model is used to estimate temperature profiles within a spirally wound D-size cell. The model is applied to the lithium/thionyl chloride cell because of the thermal management problems that this cell exhibits. Simplified one-dimensional models are presented that can be used to predict best and worst temperature profiles. The two-dimensional model is used to predict the regions of maximum temperature within the spirally wound cell. Normal discharge as well as thermal runaway conditions are investigated.
19. Mathematical modeling of leachates from ash ponds of thermal power plants.
PubMed
Singh, Gurdeep; Gupta, S K; Kumar, Ritesh; Sunderarajan, M
2007-07-01
The present study describes the development of empirical models for the prediction of various trace metals i.e., Mn, Cu, Fe, Zn and Pb found in the leachates generated from the ash ponds of various thermal power plants. The dispersion phenomenon of these trace metals followed first order reaction rate kinetics. The empirical models for individual trace metals derived from the lab scale models data correlate well with the real field data with regression coefficients varying from 0.93 to 0.98. The predicted concentrations of the trace metals varied within +/-3% of the observed values in the leachates generated from the ash ponds of four thermal power plants with standard deviation varying from 0.001 to 0.032. The empirical models derived from the study can be applied for prediction of trace metals in leachates generated from similar thermal power plants.
20. A thermal analysis of a spirally wound battery using a simple mathematical model
NASA Technical Reports Server (NTRS)
Evans, T. I.; White, R. E.
1989-01-01
A two-dimensional thermal model for spirally wound batteries has been developed. The governing equation of the model is the energy balance. Convective and insulated boundary conditions are used, and the equations are solved using a finite element code called TOPAZ2D. The finite element mesh is generated using a preprocessor to TOPAZ2D called MAZE. The model is used to estimate temperature profiles within a spirally wound D-size cell. The model is applied to the lithium/thionyl chloride cell because of the thermal management problems that this cell exhibits. Simplified one-dimensional models are presented that can be used to predict best and worst temperature profiles. The two-dimensional model is used to predict the regions of maximum temperature within the spirally wound cell. Normal discharge as well as thermal runaway conditions are investigated.
1. On 3D Dimension: Study cases for Archaeological sites
D'Urso, M. G.; Marino, C. L.; Rotondi, A.
2014-04-01
For more than a century the tridimensional vision has been of interest for scientists and users in several fields of application. The mathematical bases have remained substantially unchanged but only the new technologies have allowed us to make the vision really impressive. Photography opens new frontiers and has enriched of physical, mathematical, chemical, informatical and topographic notions by making the images so real to make the observer fully immersed into the represented scene. By means of active googless the 3D digital technique, commonly used for video games, makes possible animations without limitations in the dimension of the images thanks to the improved performances of the graphic processor units and related hardware components. In this paper we illustrate an experience made by the students of the MSc'degree course of Topography, active at the University of Cassino and Southern Lazio, in which the photography has been applied as an innovative technique for the surveying of cultural heritage. The tests foresee the use of traditional techniques of survey with 3D digital images and use of GPS sensors. The ultimate objective of our experience is the insertion in the web, allowing us the visualization of the 3D images equipped with all data. In conclusion these new methods of survey allow for the fusion of extremely different techniques, in such an impressive way to make them inseparable and justifying the origin of the neologism "Geomatics" coined at the Laval University (Canada) during the eighties.
2. 3D scanning and 3D printing as innovative technologies for fabricating personalized topical drug delivery systems.
PubMed
Goyanes, Alvaro; Det-Amornrat, Usanee; Wang, Jie; Basit, Abdul W; Gaisford, Simon
2016-07-28
3. 3D scanning and 3D printing as innovative technologies for fabricating personalized topical drug delivery systems.
PubMed
Goyanes, Alvaro; Det-Amornrat, Usanee; Wang, Jie; Basit, Abdul W; Gaisford, Simon
2016-07-28
4. Dimensional accuracy of 3D printed vertebra
Ogden, Kent; Ordway, Nathaniel; Diallo, Dalanda; Tillapaugh-Fay, Gwen; Aslan, Can
2014-03-01
3D printer applications in the biomedical sciences and medical imaging are expanding and will have an increasing impact on the practice of medicine. Orthopedic and reconstructive surgery has been an obvious area for development of 3D printer applications as the segmentation of bony anatomy to generate printable models is relatively straightforward. There are important issues that should be addressed when using 3D printed models for applications that may affect patient care; in particular the dimensional accuracy of the printed parts needs to be high to avoid poor decisions being made prior to surgery or therapeutic procedures. In this work, the dimensional accuracy of 3D printed vertebral bodies derived from CT data for a cadaver spine is compared with direct measurements on the ex-vivo vertebra and with measurements made on the 3D rendered vertebra using commercial 3D image processing software. The vertebra was printed on a consumer grade 3D printer using an additive print process using PLA (polylactic acid) filament. Measurements were made for 15 different anatomic features of the vertebral body, including vertebral body height, endplate width and depth, pedicle height and width, and spinal canal width and depth, among others. It is shown that for the segmentation and printing process used, the results of measurements made on the 3D printed vertebral body are substantially the same as those produced by direct measurement on the vertebra and measurements made on the 3D rendered vertebra.
5. Stereo 3-D Vision in Teaching Physics
Zabunov, Svetoslav
2012-03-01
Stereo 3-D vision is a technology used to present images on a flat surface (screen, paper, etc.) and at the same time to create the notion of three-dimensional spatial perception of the viewed scene. A great number of physical processes are much better understood when viewed in stereo 3-D vision compared to standard flat 2-D presentation. The current paper describes the modern stereo 3-D technologies that are applicable to various tasks in teaching physics in schools, colleges, and universities. Examples of stereo 3-D simulations developed by the author can be observed on online.
6. Software for 3D radiotherapy dosimetry. Validation
Kozicki, Marek; Maras, Piotr; Karwowski, Andrzej C.
2014-08-01
The subject of this work is polyGeVero® software (GeVero Co., Poland), which has been developed to fill the requirements of fast calculations of 3D dosimetry data with the emphasis on polymer gel dosimetry for radiotherapy. This software comprises four workspaces that have been prepared for: (i) calculating calibration curves and calibration equations, (ii) storing the calibration characteristics of the 3D dosimeters, (iii) calculating 3D dose distributions in irradiated 3D dosimeters, and (iv) comparing 3D dose distributions obtained from measurements with the aid of 3D dosimeters and calculated with the aid of treatment planning systems (TPSs). The main features and functions of the software are described in this work. Moreover, the core algorithms were validated and the results are presented. The validation was performed using the data of the new PABIGnx polymer gel dosimeter. The polyGeVero® software simplifies and greatly accelerates the calculations of raw 3D dosimetry data. It is an effective tool for fast verification of TPS-generated plans for tumor irradiation when combined with a 3D dosimeter. Consequently, the software may facilitate calculations by the 3D dosimetry community. In this work, the calibration characteristics of the PABIGnx obtained through four calibration methods: multi vial, cross beam, depth dose, and brachytherapy, are discussed as well.
7. [3D reconstructions in radiotherapy planning].
PubMed
Schlegel, W
1991-10-01
8. FastScript3D - A Companion to Java 3D
NASA Technical Reports Server (NTRS)
Koenig, Patti
2005-01-01
FastScript3D is a computer program, written in the Java 3D(TM) programming language, that establishes an alternative language that helps users who lack expertise in Java 3D to use Java 3D for constructing three-dimensional (3D)-appearing graphics. The FastScript3D language provides a set of simple, intuitive, one-line text-string commands for creating, controlling, and animating 3D models. The first word in a string is the name of a command; the rest of the string contains the data arguments for the command. The commands can also be used as an aid to learning Java 3D. Developers can extend the language by adding custom text-string commands. The commands can define new 3D objects or load representations of 3D objects from files in formats compatible with such other software systems as X3D. The text strings can be easily integrated into other languages. FastScript3D facilitates communication between scripting languages [which enable programming of hyper-text markup language (HTML) documents to interact with users] and Java 3D. The FastScript3D language can be extended and customized on both the scripting side and the Java 3D side.
9. Mapping the human cerebral cortex using 3-D medial manifolds
Szekely, Gabor; Brechbuehler, Christian; Kuebler, Olaf; Ogniewicz, Robert; Budinger, Thomas F.
1992-09-01
Novel imaging technologies provide a detailed look at structure and function of the tremendously complex and variable human brain. Optimal exploitation of the information stored in the rapidly growing collection of acquired and segmented MRI data calls for robust and reliable descriptions of the individual geometry of the cerebral cortex. A mathematical description and representation of 3-D shape, capable of dealing with form of variable appearance, is at the focus of this paper. We base our development on the Medial Axis Transformation (MAT) customarily defined in 2-D although the concept generalizes to any number of dimensions. Our implementation of the 3-D MAT combines full 3-D Voronoitesselation generated by the set of all border points with regularization procedures to obtain geometrically and topologically correct medial manifolds. The proposed algorithm was tested on synthetic objects and has been applied to 3-D MRI data of 1 mm isotropic resolution to obtain a description of the sulci in the cerebral cortex. Description and representation of the cortical anatomy is significant in clinical applications, medical research, and instrumentation developments.
10. Optical fabrication of lightweighted 3D printed mirrors
Herzog, Harrison; Segal, Jacob; Smith, Jeremy; Bates, Richard; Calis, Jacob; De La Torre, Alyssa; Kim, Dae Wook; Mici, Joni; Mireles, Jorge; Stubbs, David M.; Wicker, Ryan
2015-09-01
Direct Metal Laser Sintering (DMLS) and Electron Beam Melting (EBM) 3D printing technologies were utilized to create lightweight, optical grade mirrors out of AlSi10Mg aluminum and Ti6Al4V titanium alloys at the University of Arizona in Tucson. The mirror prototypes were polished to meet the λ/20 RMS and λ/4 P-V surface figure requirements. The intent of this project was to design topologically optimized mirrors that had a high specific stiffness and low surface displacement. Two models were designed using Altair Inspire software, and the mirrors had to endure the polishing process with the necessary stiffness to eliminate print-through. Mitigating porosity of the 3D printed mirror blanks was a challenge in the face of reconciling new printing technologies with traditional optical polishing methods. The prototypes underwent Hot Isostatic Press (HIP) and heat treatment to improve density, eliminate porosity, and relieve internal stresses. Metal 3D printing allows for nearly unlimited topological constraints on design and virtually eliminates the need for a machine shop when creating an optical quality mirror. This research can lead to an increase in mirror mounting support complexity in the manufacturing of lightweight mirrors and improve overall process efficiency. The project aspired to have many future applications of light weighted 3D printed mirrors, such as spaceflight. This paper covers the design/fab/polish/test of 3D printed mirrors, thermal/structural finite element analysis, and results.
11. 3D PDF - a means of public access to geological 3D - objects, using the example of GTA3D
Slaby, Mark-Fabian; Reimann, Rüdiger
2013-04-01
12. 3D ultrafast ultrasound imaging in vivo.
PubMed
Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-10-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32 × 32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability.
13. 3D ultrafast ultrasound imaging in vivo
Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-10-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32 × 32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.
14. 3D ultrafast ultrasound imaging in vivo.
PubMed
Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-10-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32 × 32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability. PMID:25207828
15. 3D root canal modeling for advanced endodontic treatment
Hong, Shane Y.; Dong, Janet
2002-06-01
More than 14 million teeth receive endodontic (root canal) treatment annually. Before a clinician's inspection and diagnosis, destructive access preparation by removing teeth crown and dentin is usually needed. This paper presents a non-invasive method for accessing internal tooth geometry by building 3-D tooth model from 2-D radiographic and endoscopic images to be used for an automatic prescription system of computer-aided treatment procedure planning, and for the root canal preparation by an intelligent micro drilling machine with on-line monitoring. It covers the techniques specific for dental application in the radiographic images acquirement, image enhancement, image segmentation and feature recognition, distance measurement and calibration, merging 2D image into 3D mathematical model representation and display. Included also are the methods to form references for irregular teeth geometry and to do accurately measurement with self-calibration.
16. Thermal control of high energy nuclear waste, space option. [mathematical models
NASA Technical Reports Server (NTRS)
Peoples, J. A.
1979-01-01
Problems related to the temperature and packaging of nuclear waste material for disposal in space are explored. An approach is suggested for solving both problems with emphasis on high energy density waste material. A passive cooling concept is presented which utilized conduction rods that penetrate the inner core. Data are presented to illustrate the effectiveness of the rods and the limit of their capability. A computerized thermal model is discussed and developed for the cooling concept.
17. Wow! 3D Content Awakens the Classroom
ERIC Educational Resources Information Center
Gordon, Dan
2010-01-01
From her first encounter with stereoscopic 3D technology designed for classroom instruction, Megan Timme, principal at Hamilton Park Pacesetter Magnet School in Dallas, sensed it could be transformative. Last spring, when she began pilot-testing 3D content in her third-, fourth- and fifth-grade classrooms, Timme wasn't disappointed. Students…
18. 3D, or Not to Be?
ERIC Educational Resources Information Center
Norbury, Keith
2012-01-01
It may be too soon for students to be showing up for class with popcorn and gummy bears, but technology similar to that behind the 3D blockbuster movie "Avatar" is slowly finding its way into college classrooms. 3D classroom projectors are taking students on fantastic voyages inside the human body, to the ruins of ancient Greece--even to faraway…
19. 3D Printed Block Copolymer Nanostructures
ERIC Educational Resources Information Center
Scalfani, Vincent F.; Turner, C. Heath; Rupar, Paul A.; Jenkins, Alexander H.; Bara, Jason E.
2015-01-01
The emergence of 3D printing has dramatically advanced the availability of tangible molecular and extended solid models. Interestingly, there are few nanostructure models available both commercially and through other do-it-yourself approaches such as 3D printing. This is unfortunate given the importance of nanotechnology in science today. In this…
20. Immersive 3D Geovisualization in Higher Education
ERIC Educational Resources Information Center
Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold
2015-01-01
In this study, we investigate how immersive 3D geovisualization can be used in higher education. Based on MacEachren and Kraak's geovisualization cube, we examine the usage of immersive 3D geovisualization and its usefulness in a research-based learning module on flood risk, called GEOSimulator. Results of a survey among participating students…
1. 3D elastic control for mobile devices.
PubMed
Hachet, Martin; Pouderoux, Joachim; Guitton, Pascal
2008-01-01
To increase the input space of mobile devices, the authors developed a proof-of-concept 3D elastic controller that easily adapts to mobile devices. This embedded device improves the completion of high-level interaction tasks such as visualization of large documents and navigation in 3D environments. It also opens new directions for tomorrow's mobile applications.
2. Static & Dynamic Response of 3D Solids
1996-07-15
NIKE3D is a large deformations 3D finite element code used to obtain the resulting displacements and stresses from multi-body static and dynamic structural thermo-mechanics problems with sliding interfaces. Many nonlinear and temperature dependent constitutive models are available.
3. 3D Printing. What's the Harm?
ERIC Educational Resources Information Center
Love, Tyler S.; Roy, Ken
2016-01-01
Health concerns from 3D printing were first documented by Stephens, Azimi, Orch, and Ramos (2013), who found that commercially available 3D printers were producing hazardous levels of ultrafine particles (UFPs) and volatile organic compounds (VOCs) when plastic materials were melted through the extruder. UFPs are particles less than 100 nanometers…
4. 3D Printing of Molecular Models
ERIC Educational Resources Information Center
2016-01-01
Physical molecular models have played a valuable role in our understanding of the invisible nano-scale world. We discuss 3D printing and its use in producing models of the molecules of life. Complex biomolecular models, produced from 3D printed parts, can demonstrate characteristics of molecular structure and function, such as viral self-assembly,…
5. A 3D Geostatistical Mapping Tool
SciTech Connect
Weiss, W. W.; Stevenson, Graig; Patel, Ketan; Wang, Jun
1999-02-09
This software provides accurate 3D reservoir modeling tools and high quality 3D graphics for PC platforms enabling engineers and geologists to better comprehend reservoirs and consequently improve their decisions. The mapping algorithms are fractals, kriging, sequential guassian simulation, and three nearest neighbor methods.
6. Pathways for Learning from 3D Technology
ERIC Educational Resources Information Center
Carrier, L. Mark; Rab, Saira S.; Rosen, Larry D.; Vasquez, Ludivina; Cheever, Nancy A.
2012-01-01
The purpose of this study was to find out if 3D stereoscopic presentation of information in a movie format changes a viewer's experience of the movie content. Four possible pathways from 3D presentation to memory and learning were considered: a direct connection based on cognitive neuroscience research; a connection through "immersion" in that 3D…
7. Stereo 3-D Vision in Teaching Physics
ERIC Educational Resources Information Center
Zabunov, Svetoslav
2012-01-01
Stereo 3-D vision is a technology used to present images on a flat surface (screen, paper, etc.) and at the same time to create the notion of three-dimensional spatial perception of the viewed scene. A great number of physical processes are much better understood when viewed in stereo 3-D vision compared to standard flat 2-D presentation. The…
8. Clinical applications of 3-D dosimeters
Wuu, Cheng-Shie
2015-01-01
Both 3-D gels and radiochromic plastic dosimeters, in conjunction with dose image readout systems (MRI or optical-CT), have been employed to measure 3-D dose distributions in many clinical applications. The 3-D dose maps obtained from these systems can provide a useful tool for clinical dose verification for complex treatment techniques such as IMRT, SRS/SBRT, brachytherapy, and proton beam therapy. These complex treatments present high dose gradient regions in the boundaries between the target and surrounding critical organs. Dose accuracy in these areas can be critical, and may affect treatment outcome. In this review, applications of 3-D gels and PRESAGE dosimeter are reviewed and evaluated in terms of their performance in providing information on clinical dose verification as well as commissioning of various treatment modalities. Future interests and clinical needs on studies of 3-D dosimetry are also discussed.
9. Fabrication of 3D Silicon Sensors
SciTech Connect
Kok, A.; Hansen, T.E.; Hansen, T.A.; Lietaer, N.; Summanwar, A.; Kenney, C.; Hasi, J.; Da Via, C.; Parker, S.I.; /Hawaii U.
2012-06-06
Silicon sensors with a three-dimensional (3-D) architecture, in which the n and p electrodes penetrate through the entire substrate, have many advantages over planar silicon sensors including radiation hardness, fast time response, active edge and dual readout capabilities. The fabrication of 3D sensors is however rather complex. In recent years, there have been worldwide activities on 3D fabrication. SINTEF in collaboration with Stanford Nanofabrication Facility have successfully fabricated the original (single sided double column type) 3D detectors in two prototype runs and the third run is now on-going. This paper reports the status of this fabrication work and the resulted yield. The work of other groups such as the development of double sided 3D detectors is also briefly reported.
10. BEAMS3D Neutral Beam Injection Model
SciTech Connect
Lazerson, Samuel
2014-04-14
With the advent of applied 3D fi elds in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous velocity reduction, and pitch angle scattering are modeled with the ADAS atomic physics database [1]. Benchmark calculations are presented to validate the collisionless particle orbits, neutral beam injection model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields.
11. 3D Reconstruction of Coronary Artery Vascular Smooth Muscle Cells
PubMed Central
Luo, Tong; Chen, Huan; Kassab, Ghassan S.
2016-01-01
Aims The 3D geometry of individual vascular smooth muscle cells (VSMCs), which are essential for understanding the mechanical function of blood vessels, are currently not available. This paper introduces a new 3D segmentation algorithm to determine VSMC morphology and orientation. Methods and Results A total of 112 VSMCs from six porcine coronary arteries were used in the analysis. A 3D semi-automatic segmentation method was developed to reconstruct individual VSMCs from cell clumps as well as to extract the 3D geometry of VSMCs. A new edge blocking model was introduced to recognize cell boundary while an edge growing was developed for optimal interpolation and edge verification. The proposed methods were designed based on Region of Interest (ROI) selected by user and interactive responses of limited key edges. Enhanced cell boundary features were used to construct the cell’s initial boundary for further edge growing. A unified framework of morphological parameters (dimensions and orientations) was proposed for the 3D volume data. Virtual phantom was designed to validate the tilt angle measurements, while other parameters extracted from 3D segmentations were compared with manual measurements to assess the accuracy of the algorithm. The length, width and thickness of VSMCs were 62.9±14.9μm, 4.6±0.6μm and 6.2±1.8μm (mean±SD). In longitudinal-circumferential plane of blood vessel, VSMCs align off the circumferential direction with two mean angles of -19.4±9.3° and 10.9±4.7°, while an out-of-plane angle (i.e., radial tilt angle) was found to be 8±7.6° with median as 5.7°. Conclusions A 3D segmentation algorithm was developed to reconstruct individual VSMCs of blood vessel walls based on optical image stacks. The results were validated by a virtual phantom and manual measurement. The obtained 3D geometries can be utilized in mathematical models and leads a better understanding of vascular mechanical properties and function. PMID:26882342
12. 3D Ultrafast Ultrasound Imaging In Vivo
PubMed Central
Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu
2014-01-01
Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative real-time imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in three dimensions based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32×32 matrix-array probe. Its capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 3-D Ultrafast Doppler Imaging and finally 3D Ultrafast combined Tissue and Flow Doppler. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3-D Ultrafast Doppler was used to obtain 3-D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, for the first time, the complex 3-D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, and the 3-D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3-D Ultrafast Ultrasound Imaging for the 3-D real-time mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra- and inter-observer variability. PMID:25207828
13. The psychology of the 3D experience
Janicke, Sophie H.; Ellis, Andrew
2013-03-01
With 3D televisions expected to reach 50% home saturation as early as 2016, understanding the psychological mechanisms underlying the user response to 3D technology is critical for content providers, educators and academics. Unfortunately, research examining the effects of 3D technology has not kept pace with the technology's rapid adoption, resulting in large-scale use of a technology about which very little is actually known. Recognizing this need for new research, we conducted a series of studies measuring and comparing many of the variables and processes underlying both 2D and 3D media experiences. In our first study, we found narratives within primetime dramas had the power to shift viewer attitudes in both 2D and 3D settings. However, we found no difference in persuasive power between 2D and 3D content. We contend this lack of effect was the result of poor conversion quality and the unique demands of 3D production. In our second study, we found 3D technology significantly increased enjoyment when viewing sports content, yet offered no added enjoyment when viewing a movie trailer. The enhanced enjoyment of the sports content was shown to be the result of heightened emotional arousal and attention in the 3D condition. We believe the lack of effect found for the movie trailer may be genre-related. In our final study, we found 3D technology significantly enhanced enjoyment of two video games from different genres. The added enjoyment was found to be the result of an increased sense of presence.
14. Low-cost 3D rangefinder system
Chen, Bor-Tow; Lou, Wen-Shiou; Chen, Chia-Chen; Lin, Hsien-Chang
1998-06-01
Nowadays, 3D data are popularly performed in computer, and 3D browsers manipulate 3D model in the virtual world. Yet, till now, 3D digitizer is still a high-cost product and not a familiar equipment. In order to meet the requirement of 3D fancy world, in this paper, the concept of a low-cost 3D digitizer system is proposed to catch 3D range data from objects. The specified optical design of the 3D extraction is effective to depress the size, and the processing software of the system is compatible with PC to promote its portable capability. Both features contribute a low-cost system in PC environment in contrast to a large system bundled in an expensive workstation platform. In the structure of 3D extraction, laser beam and CCD camera are adopted to construct a 3D sensor. Instead of 2 CCD cameras for capturing laser lines twice before, a 2-in-1 system is proposed to merge 2 images in one CCD which still retains the information of two fields of views to inhibit occlusion problems. Besides, optical paths of two camera views are reflected by mirror in order that the volume of the system can be minified with one rotary axis only. It makes a portable system be more possible to work. Combined with the processing software executable in PC windows system, the proposed system not only saves hardware cost but also processing time of software. The system performance achieves 0.05 mm accuracy. It shows that a low- cost system is more possible to be high-performance.
15. 3D Visualization Development of SIUE Campus
Nellutla, Shravya
Geographic Information Systems (GIS) has progressed from the traditional map-making to the modern technology where the information can be created, edited, managed and analyzed. Like any other models, maps are simplified representations of real world. Hence visualization plays an essential role in the applications of GIS. The use of sophisticated visualization tools and methods, especially three dimensional (3D) modeling, has been rising considerably due to the advancement of technology. There are currently many off-the-shelf technologies available in the market to build 3D GIS models. One of the objectives of this research was to examine the available ArcGIS and its extensions for 3D modeling and visualization and use them to depict a real world scenario. Furthermore, with the advent of the web, a platform for accessing and sharing spatial information on the Internet, it is possible to generate interactive online maps. Integrating Internet capacity with GIS functionality redefines the process of sharing and processing the spatial information. Enabling a 3D map online requires off-the-shelf GIS software, 3D model builders, web server, web applications and client server technologies. Such environments are either complicated or expensive because of the amount of hardware and software involved. Therefore, the second objective of this research was to investigate and develop simpler yet cost-effective 3D modeling approach that uses available ArcGIS suite products and the free 3D computer graphics software for designing 3D world scenes. Both ArcGIS Explorer and ArcGIS Online will be used to demonstrate the way of sharing and distributing 3D geographic information on the Internet. A case study of the development of 3D campus for the Southern Illinois University Edwardsville is demonstrated.
16. Measurements of 3D slip velocities and plasma column lengths of a gliding arc discharge
SciTech Connect
Zhu, Jiajian; Gao, Jinlong; Ehn, Andreas; Aldén, Marcus; Li, Zhongshan E-mail: [email protected]; Moseev, Dmitry; Kusano, Yukihiro; Salewski, Mirko; Alpers, Andreas E-mail: [email protected]; Gritzmann, Peter; Schwenk, Martin
2015-01-26
A non-thermal gliding arc discharge was generated at atmospheric pressure in an air flow. The dynamics of the plasma column and tracer particles were recorded using two synchronized high-speed cameras. Whereas the data analysis for such systems has previously been performed in 2D (analyzing the single camera image), we provide here a 3D data analysis that includes 3D reconstructions of the plasma column and 3D particle tracking velocimetry based on discrete tomography methods. The 3D analysis, in particular, the determination of the 3D slip velocity between the plasma column and the gas flow, gives more realistic insight into the convection cooling process. Additionally, with the determination of the 3D slip velocity and the 3D length of the plasma column, we give more accurate estimates for the drag force, the electric field strength, the power per unit length, and the radius of the conducting zone of the plasma column.
17. Direct inversion of digital 3D Fraunhofer holography maps
Podorov, Sergei G.; Förster, Eckhart
2016-01-01
The Differential Fourier Holography (DFH) gives an exact mathematical solution of the inverse problem of diffraction in the Fraunhofer regime. After the first publication [1] the Differential Fourier Holography was successfully applied in many experiments to obtain amplitude and phase information about two-dimensional (2D) images. In this article we demonstrate numerically the possibility to apply the DFH also for investigation of unknown 3D Objects. The first simulation is made for a double-spiral structure plus a line as a reference object.
18. Visualization package for 3D laser-scanned geometry
Neumann, Paul F.; Sadler, Lewis L.
1993-06-01
A computer software package named LEGO was designed and implemented to enable medical personnel to explore and manipulate laser scanned 3D geometry obtained from a Cyberware 4020PS scanner. This type of scanner reconstructs a real world object into a mathematical computer model by collecting thousands of depth measurement using a low powered laser. LEGO consists of a collection of tools that can be interactively combined to accomplish complex tasks. Tools fall into five major categories: viewing, simple, quantitative, manipulative, and miscellaneous. This paper is based on a masters thesis obtained from the University of Illinois at Chicago.
19. 3-D HYDRODYNAMIC MODELING IN A GEOSPATIAL FRAMEWORK
SciTech Connect
Bollinger, J; Alfred Garrett, A; Larry Koffman, L; David Hayes, D
2006-08-24
3-D hydrodynamic models are used by the Savannah River National Laboratory (SRNL) to simulate the transport of thermal and radionuclide discharges in coastal estuary systems. Development of such models requires accurate bathymetry, coastline, and boundary condition data in conjunction with the ability to rapidly discretize model domains and interpolate the required geospatial data onto the domain. To facilitate rapid and accurate hydrodynamic model development, SRNL has developed a pre- and post-processor application in a geospatial framework to automate the creation of models using existing data. This automated capability allows development of very detailed models to maximize exploitation of available surface water radionuclide sample data and thermal imagery.
20. Medical 3D Printing for the Radiologist.
PubMed
Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J
2015-01-01
While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article.
1. 3D facial expression modeling for recognition
Lu, Xiaoguang; Jain, Anil K.; Dass, Sarat C.
2005-03-01
Current two-dimensional image based face recognition systems encounter difficulties with large variations in facial appearance due to the pose, illumination and expression changes. Utilizing 3D information of human faces is promising for handling the pose and lighting variations. While the 3D shape of a face does not change due to head pose (rigid) and lighting changes, it is not invariant to the non-rigid facial movement and evolution, such as expressions and aging effect. We propose a facial surface matching framework to match multiview facial scans to a 3D face model, where the (non-rigid) expression deformation is explicitly modeled for each subject, resulting in a person-specific deformation model. The thin plate spline (TPS) is applied to model the deformation based on the facial landmarks. The deformation is applied to the 3D neutral expression face model to synthesize the corresponding expression. Both the neutral and the synthesized 3D surface models are used to match a test scan. The surface registration and matching between a test scan and a 3D model are achieved by a modified Iterative Closest Point (ICP) algorithm. Preliminary experimental results demonstrate that the proposed expression modeling and recognition-by-synthesis schemes improve the 3D matching accuracy.
2. Digital relief generation from 3D models
Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian
2016-09-01
It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.
3. Medical 3D Printing for the Radiologist.
PubMed
Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A; Cai, Tianrun; Kumamaru, Kanako K; George, Elizabeth; Wake, Nicole; Caterson, Edward J; Pomahac, Bohdan; Ho, Vincent B; Grant, Gerald T; Rybicki, Frank J
2015-01-01
While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. PMID:26562233
4. Perception of detail in 3D images
Heynderickx, Ingrid; Kaptein, Ronald
2009-01-01
A lot of current 3D displays suffer from the fact that their spatial resolution is lower compared to their 2D counterparts. One reason for this is that the multiple views needed to generate 3D are often spatially multiplexed. Besides this, imperfect separation of the left- and right-eye view leads to blurring or ghosting, and therefore to a decrease in perceived sharpness. However, people watching stereoscopic videos have reported that the 3D scene contained more details, compared to the 2D scene with identical spatial resolution. This is an interesting notion, that has never been tested in a systematic and quantitative way. To investigate this effect, we had people compare the amount of detail ("detailedness") in pairs of 2D and 3D images. A blur filter was applied to one of the two images, and the blur level was varied using an adaptive staircase procedure. In this way, the blur threshold for which the 2D and 3D image contained perceptually the same amount of detail could be found. Our results show that the 3D image needed to be blurred more than the 2D image. This confirms the earlier qualitative findings that 3D images contain perceptually more details than 2D images with the same spatial resolution.
5. 3D bioprinting of tissues and organs.
PubMed
Murphy, Sean V; Atala, Anthony
2014-08-01
Additive manufacturing, otherwise known as three-dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education and medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. Compared with non-biological printing, 3D bioprinting involves additional complexities, such as the choice of materials, cell types, growth and differentiation factors, and technical challenges related to the sensitivities of living cells and the construction of tissues. Addressing these complexities requires the integration of technologies from the fields of engineering, biomaterials science, cell biology, physics and medicine. 3D bioprinting has already been used for the generation and transplantation of several tissues, including multilayered skin, bone, vascular grafts, tracheal splints, heart tissue and cartilaginous structures. Other applications include developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology. PMID:25093879
6. Medical 3D Printing for the Radiologist
PubMed Central
Mitsouras, Dimitris; Liacouras, Peter; Imanzadeh, Amir; Giannopoulos, Andreas A.; Cai, Tianrun; Kumamaru, Kanako K.; George, Elizabeth; Wake, Nicole; Caterson, Edward J.; Pomahac, Bohdan; Ho, Vincent B.; Grant, Gerald T.
2015-01-01
While use of advanced visualization in radiology is instrumental in diagnosis and communication with referring clinicians, there is an unmet need to render Digital Imaging and Communications in Medicine (DICOM) images as three-dimensional (3D) printed models capable of providing both tactile feedback and tangible depth information about anatomic and pathologic states. Three-dimensional printed models, already entrenched in the nonmedical sciences, are rapidly being embraced in medicine as well as in the lay community. Incorporating 3D printing from images generated and interpreted by radiologists presents particular challenges, including training, materials and equipment, and guidelines. The overall costs of a 3D printing laboratory must be balanced by the clinical benefits. It is expected that the number of 3D-printed models generated from DICOM images for planning interventions and fabricating implants will grow exponentially. Radiologists should at a minimum be familiar with 3D printing as it relates to their field, including types of 3D printing technologies and materials used to create 3D-printed anatomic models, published applications of models to date, and clinical benefits in radiology. Online supplemental material is available for this article. ©RSNA, 2015 PMID:26562233
7. High density 3D printed microfluidic valves, pumps, and multiplexers.
PubMed
Gong, Hua; Woolley, Adam T; Nordin, Gregory P
2016-07-01
In this paper we demonstrate that 3D printing with a digital light processor stereolithographic (DLP-SLA) 3D printer can be used to create high density microfluidic devices with active components such as valves and pumps. Leveraging our previous work on optical formulation of inexpensive resins (RSC Adv., 2015, 5, 106621), we demonstrate valves with only 10% of the volume of our original 3D printed valves (Biomicrofluidics, 2015, 9, 016501), which were already the smallest that have been reported. Moreover, we show that incorporation of a thermal initiator in the resin formulation along with a post-print bake can dramatically improve the durability of 3D printed valves up to 1 million actuations. Using two valves and a valve-like displacement chamber (DC), we also create compact 3D printed pumps. With 5-phase actuation and a 15 ms phase interval, we obtain pump flow rates as high as 40 μL min(-1). We also characterize maximum pump back pressure (i.e., maximum pressure the pump can work against), maximum flow rate (flow rate when there is zero back pressure), and flow rate as a function of the height of the pump outlet. We further demonstrate combining 5 valves and one DC to create a 3-to-2 multiplexer with integrated pump. In addition to serial multiplexing, we also show that the device can operate as a mixer. Importantly, we illustrate the rapid fabrication and test cycles that 3D printing makes possible by implementing a new multiplexer design to improve mixing, and fabricate and test it within one day.
8. High density 3D printed microfluidic valves, pumps, and multiplexers.
PubMed
Gong, Hua; Woolley, Adam T; Nordin, Gregory P
2016-07-01
In this paper we demonstrate that 3D printing with a digital light processor stereolithographic (DLP-SLA) 3D printer can be used to create high density microfluidic devices with active components such as valves and pumps. Leveraging our previous work on optical formulation of inexpensive resins (RSC Adv., 2015, 5, 106621), we demonstrate valves with only 10% of the volume of our original 3D printed valves (Biomicrofluidics, 2015, 9, 016501), which were already the smallest that have been reported. Moreover, we show that incorporation of a thermal initiator in the resin formulation along with a post-print bake can dramatically improve the durability of 3D printed valves up to 1 million actuations. Using two valves and a valve-like displacement chamber (DC), we also create compact 3D printed pumps. With 5-phase actuation and a 15 ms phase interval, we obtain pump flow rates as high as 40 μL min(-1). We also characterize maximum pump back pressure (i.e., maximum pressure the pump can work against), maximum flow rate (flow rate when there is zero back pressure), and flow rate as a function of the height of the pump outlet. We further demonstrate combining 5 valves and one DC to create a 3-to-2 multiplexer with integrated pump. In addition to serial multiplexing, we also show that the device can operate as a mixer. Importantly, we illustrate the rapid fabrication and test cycles that 3D printing makes possible by implementing a new multiplexer design to improve mixing, and fabricate and test it within one day. PMID:27242064
9. FUN3D Manual: 12.7
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2015-01-01
This manual describes the installation and execution of FUN3D version 12.7, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
10. FUN3D Manual: 13.0
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bill; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2016-01-01
This manual describes the installation and execution of FUN3D version 13.0, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
11. FUN3D Manual: 12.6
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2015-01-01
This manual describes the installation and execution of FUN3D version 12.6, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
12. FUN3D Manual: 12.5
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, William L.; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2014-01-01
This manual describes the installation and execution of FUN3D version 12.5, including optional dependent packages. FUN3D is a suite of computational uid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables ecient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
13. FUN3D Manual: 12.9
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2016-01-01
This manual describes the installation and execution of FUN3D version 12.9, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
14. FUN3D Manual: 12.8
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Carlson, Jan-Renee; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2015-01-01
This manual describes the installation and execution of FUN3D version 12.8, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixed-element unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
15. FUN3D Manual: 12.4
NASA Technical Reports Server (NTRS)
Biedron, Robert T.; Derlaga, Joseph M.; Gnoffo, Peter A.; Hammond, Dana P.; Jones, William T.; Kleb, Bil; Lee-Rausch, Elizabeth M.; Nielsen, Eric J.; Park, Michael A.; Rumsey, Christopher L.; Thomas, James L.; Wood, William A.
2014-01-01
This manual describes the installation and execution of FUN3D version 12.4, including optional dependent packages. FUN3D is a suite of computational fluid dynamics simulation and design tools that uses mixedelement unstructured grids in a large number of formats, including structured multiblock and overset grid systems. A discretely-exact adjoint solver enables efficient gradient-based design and grid adaptation to reduce estimated discretization error. FUN3D is available with and without a reacting, real-gas capability. This generic gas option is available only for those persons that qualify for its beta release status.
16. VALIDATION OF IMPROVED 3D ATR MODEL
SciTech Connect
Soon Sam Kim; Bruce G. Schnitzler
2005-11-01
A full-core Monte Carlo based 3D model of the Advanced Test Reactor (ATR) was previously developed. [1] An improved 3D model has been developed by the International Criticality Safety Benchmark Evaluation Project (ICSBEP) to eliminate homogeneity of fuel plates of the old model, incorporate core changes into the new model, and to validate against a newer, more complicated core configuration. This new 3D model adds capability for fuel loading design and azimuthal power peaking studies of the ATR fuel elements.
17. A high capacity 3D steganography algorithm.
PubMed
Chao, Min-Wen; Lin, Chao-hung; Yu, Cheng-Wei; Lee, Tong-Yee
2009-01-01
In this paper, we present a very high-capacity and low-distortion 3D steganography scheme. Our steganography approach is based on a novel multilayered embedding scheme to hide secret messages in the vertices of 3D polygon models. Experimental results show that the cover model distortion is very small as the number of hiding layers ranges from 7 to 13 layers. To the best of our knowledge, this novel approach can provide much higher hiding capacity than other state-of-the-art approaches, while obeying the low distortion and security basic requirements for steganography on 3D models.
18. How We 3D-Print Aerogel
SciTech Connect
2015-04-23
A new type of graphene aerogel will make for better energy storage, sensors, nanoelectronics, catalysis and separations. Lawrence Livermore National Laboratory researchers have made graphene aerogel microlattices with an engineered architecture via a 3D printing technique known as direct ink writing. The research appears in the April 22 edition of the journal, Nature Communications. The 3D printed graphene aerogels have high surface area, excellent electrical conductivity, are lightweight, have mechanical stiffness and exhibit supercompressibility (up to 90 percent compressive strain). In addition, the 3D printed graphene aerogel microlattices show an order of magnitude improvement over bulk graphene materials and much better mass transport.
19. FIT3D: Fitting optical spectra
Sánchez, S. F.; Pérez, E.; Sánchez-Blázquez, P.; González, J. J.; Rosales-Ortega, F. F.; Cano-Díaz, M.; López-Cobá, C.; Marino, R. A.; Gil de Paz, A.; Mollá, M.; López-Sánchez, A. R.; Ascasibar, Y.; Barrera-Ballesteros, J.
2016-09-01
FIT3D fits optical spectra to deblend the underlying stellar population and the ionized gas, and extract physical information from each component. FIT3D is focused on the analysis of Integral Field Spectroscopy data, but is not restricted to it, and is the basis of Pipe3D, a pipeline used in the analysis of datasets like CALIFA, MaNGA, and SAMI. It can run iteratively or in an automatic way to derive the parameters of a large set of spectra.
20. Investigations in massive 3D gravity
SciTech Connect
Accioly, Antonio; Helayeel-Neto, Jose; Morais, Jefferson; Turcati, Rodrigo; Scatena, Eslley
2011-05-15
Some interesting gravitational properties of the Bergshoeff-Hohm-Townsend model (massive 3D gravity), such as the presence of a short-range gravitational force in the nonrelativistic limit and the existence of an impact-parameter-dependent gravitational deflection angle, are studied. Interestingly enough, these phenomena have no counterpart in the usual Einstein 3D gravity. In order to better understand the two aforementioned gravitational properties, they are also analyzed in the framework of 3D higher-derivative gravity with the Einstein-Hilbert term with the 'wrong sign'.
1. An Improved Version of TOPAZ 3D
SciTech Connect
Krasnykh, Anatoly
2003-07-29
An improved version of the TOPAZ 3D gun code is presented as a powerful tool for beam optics simulation. In contrast to the previous version of TOPAZ 3D, the geometry of the device under test is introduced into TOPAZ 3D directly from a CAD program, such as Solid Edge or AutoCAD. In order to have this new feature, an interface was developed, using the GiD software package as a meshing code. The article describes this method with two models to illustrate the results.
2. JAR3D Webserver: Scoring and aligning RNA loop sequences to known 3D motifs
PubMed Central
Roll, James; Zirbel, Craig L.; Sweeney, Blake; Petrov, Anton I.; Leontis, Neocles
2016-01-01
Many non-coding RNAs have been identified and may function by forming 2D and 3D structures. RNA hairpin and internal loops are often represented as unstructured on secondary structure diagrams, but RNA 3D structures show that most such loops are structured by non-Watson–Crick basepairs and base stacking. Moreover, different RNA sequences can form the same RNA 3D motif. JAR3D finds possible 3D geometries for hairpin and internal loops by matching loop sequences to motif groups from the RNA 3D Motif Atlas, by exact sequence match when possible, and by probabilistic scoring and edit distance for novel sequences. The scoring gauges the ability of the sequences to form the same pattern of interactions observed in 3D structures of the motif. The JAR3D webserver at http://rna.bgsu.edu/jar3d/ takes one or many sequences of a single loop as input, or else one or many sequences of longer RNAs with multiple loops. Each sequence is scored against all current motif groups. The output shows the ten best-matching motif groups. Users can align input sequences to each of the motif groups found by JAR3D. JAR3D will be updated with every release of the RNA 3D Motif Atlas, and so its performance is expected to improve over time. PMID:27235417
3. XML3D and Xflow: combining declarative 3D for the Web with generic data flows.
PubMed
Klein, Felix; Sons, Kristian; Rubinstein, Dmitri; Slusallek, Philipp
2013-01-01
Researchers have combined XML3D, which provides declarative, interactive 3D scene descriptions based on HTML5, with Xflow, a language for declarative, high-performance data processing. The result lets Web developers combine a 3D scene graph with data flows for dynamic meshes, animations, image processing, and postprocessing. PMID:24808080
4. Do-It-Yourself: 3D Models of Hydrogenic Orbitals through 3D Printing
ERIC Educational Resources Information Center
Griffith, Kaitlyn M.; de Cataldo, Riccardo; Fogarty, Keir H.
2016-01-01
Introductory chemistry students often have difficulty visualizing the 3-dimensional shapes of the hydrogenic electron orbitals without the aid of physical 3D models. Unfortunately, commercially available models can be quite expensive. 3D printing offers a solution for producing models of hydrogenic orbitals. 3D printing technology is widely…
5. 3D J-Integral Capability in Grizzly
SciTech Connect
Benjamin Spencer; Marie Backman; Pritam Chakraborty; William Hoffman
2014-09-01
This report summarizes work done to develop a capability to evaluate fracture contour J-Integrals in 3D in the Grizzly code. In the current fiscal year, a previously-developed 2D implementation of a J-Integral evaluation capability has been extended to work in 3D, and to include terms due both to mechanically-induced strains and due to gradients in thermal strains. This capability has been verified against a benchmark solution on a model of a curved crack front in 3D. The thermal term in this integral has been verified against a benchmark problem with a thermal gradient. These developments are part of a larger effort to develop Grizzly as a tool that can be used to predict the evolution of aging processes in nuclear power plant systems, structures, and components, and assess their capacity after being subjected to those aging processes. The capabilities described here have been developed to enable evaluations of Mode- stress intensity factors on axis-aligned flaws in reactor pressure vessels. These can be compared with the fracture toughness of the material to determine whether a pre-existing flaw would begin to propagate during a pos- tulated pressurized thermal shock accident. This report includes a demonstration calculation to show how Grizzly is used to perform a deterministic assessment of such a flaw propagation in a degraded reactor pressure vessel under pressurized thermal shock conditions. The stress intensity is calculated from J, and the toughness is computed using the fracture master curve and the degraded ductile to brittle transition temperature.
6. A mathematical and numerical framework for the analysis of compressible thermal convection in gases at very high temperatures
Lappa, Marcello
2016-05-01
The relevance of non-equilibrium phenomena, nonlinear behavior, gravitational effects and fluid compressibility in a wide range of problems related to high-temperature gas-dynamics, especially in thermal, mechanical and nuclear engineering, calls for a concerted approach using the tools of the kinetic theory of gases, statistical physics, quantum mechanics, thermodynamics and mathematical modeling in synergy with advanced numerical strategies for the solution of the Navier-Stokes equations. The reason behind such a need is that in many instances of relevance in this field one witnesses a departure from canonical models and the resulting inadequacy of standard CFD approaches, especially those traditionally used to deal with thermal (buoyancy) convection problems. Starting from microscopic considerations and typical concepts of molecular dynamics, passing through the Boltzmann equation and its known solutions, we show how it is possible to remove past assumptions and elaborate an algorithm capable of targeting the broadest range of applications. Moving beyond the Boussinesq approximation, the Sutherland law and the principle of energy equipartition, the resulting method allows most of the fluid properties (density, viscosity, thermal conductivity, heat capacity and diffusivity, etc.) to be derived in a rational and natural way while keeping empirical contamination to the minimum. Special attention is deserved as well to the well-known pressure issue. With the application of the socalled multiple pressure variables concept and a projection-like numerical approach, difficulties with such a term in the momentum equation are circumvented by allowing the hydrodynamic pressure to decouple from its thermodynamic counterpart. The final result is a flexible and modular framework that on the one hand is able to account for all the molecule (translational, rotational and vibrational) degrees of freedom and their effective excitation, and on the other hand can guarantee adequate
7. TRMM 3-D Flyby of Ingrid
NASA Video Gallery
This 3-D flyby of Tropical Storm Ingrid's rainfall was created from TRMM satellite data for Sept. 16. Heaviest rainfall appears in red towers over the Gulf of Mexico, while moderate rainfall stretc...
8. 3DSEM: A 3D microscopy dataset.
PubMed
Tafti, Ahmad P; Kirkpatrick, Andrew B; Holz, Jessica D; Owen, Heather A; Yu, Zeyun
2016-03-01
The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples. PMID:26779561
9. 3DSEM: A 3D microscopy dataset
PubMed Central
Tafti, Ahmad P.; Kirkpatrick, Andrew B.; Holz, Jessica D.; Owen, Heather A.; Yu, Zeyun
2015-01-01
The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples. PMID:26779561
10. Tropical Cyclone Jack in Satellite 3-D
NASA Video Gallery
This 3-D flyby from NASA's TRMM satellite of Tropical Cyclone Jack on April 21 shows that some of the thunderstorms were shown by TRMM PR were still reaching height of at least 17 km (10.5 miles). ...
11. An Augmented Reality based 3D Catalog
This paper presents a 3D catalog system that uses Augmented Reality technology. The use of Web-based catalog systems that present products in 3D form is increasing in various fields, along with the rapid and widespread adoption of Electronic Commerce. However, 3D shapes could previously only be seen in a virtual space, and it was difficult to understand how the products would actually look in the real world. To solve this, we propose a method that combines the virtual and real worlds simply and intuitively. The method applies Augmented Reality technology, and the system developed based on the method enables users to evaluate 3D virtual products in a real environment.
12. 3D-printed bioanalytical devices.
PubMed
Bishop, Gregory W; Satterwhite-Warden, Jennifer E; Kadimisetty, Karteek; Rusling, James F
2016-07-15
While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.
13. Cyclone Rusty's Landfall in 3-D
NASA Video Gallery
This 3-D image derived from NASA's TRMM satellite Precipitation Radar data on February 26, 2013 at 0654 UTC showed that the tops of some towering thunderstorms in Rusty's eye wall were reaching hei...
14. 3-D Animation of Typhoon Bopha
NASA Video Gallery
This 3-D animation of NASA's TRMM satellite data showed Typhoon Bopha tracking over the Philippines on Dec. 3 and moving into the Sulu Sea on Dec. 4, 2012. TRMM saw heavy rain (red) was falling at ...
15. Palacios field: A 3-D case history
SciTech Connect
McWhorter, R.; Torguson, B.
1994-12-31
In late 1992, Mitchell Energy Corporation acquired a 7.75 sq mi (20.0 km{sup 2}) 3-D seismic survey over Palacios field. Matagorda County, Texas. The company shot the survey to help evaluate the field for further development by delineating the fault pattern of the producing Middle Oligocene Frio interval. They compare the mapping of the field before and after the 3-D survey. This comparison shows that the 3-D volume yields superior fault imaging and interpretability compared to the dense 2-D data set. The problems with the 2-D data set are improper imaging of small and oblique faults and insufficient coverage over a complex fault pattern. Whereas the 2-D data set validated a simple fault model, the 3-D volume revealed a more complex history of faulting that includes three different fault systems. This discovery enabled them to reconstruct the depositional and structural history of Palacios field.
16. 3D-printed bioanalytical devices
Bishop, Gregory W.; Satterwhite-Warden, Jennifer E.; Kadimisetty, Karteek; Rusling, James F.
2016-07-01
While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices.
17. 3-D TRMM Flyby of Hurricane Amanda
NASA Video Gallery
The TRMM satellite flew over Hurricane Amanda on Tuesday, May 27 at 1049 UTC (6:49 a.m. EDT) and captured rainfall rates and cloud height data that was used to create this 3-D simulated flyby. Cred...
18. Eyes on the Earth 3D
NASA Technical Reports Server (NTRS)
Kulikov, anton I.; Doronila, Paul R.; Nguyen, Viet T.; Jackson, Randal K.; Greene, William M.; Hussey, Kevin J.; Garcia, Christopher M.; Lopez, Christian A.
2013-01-01
Eyes on the Earth 3D software gives scientists, and the general public, a realtime, 3D interactive means of accurately viewing the real-time locations, speed, and values of recently collected data from several of NASA's Earth Observing Satellites using a standard Web browser (climate.nasa.gov/eyes). Anyone with Web access can use this software to see where the NASA fleet of these satellites is now, or where they will be up to a year in the future. The software also displays several Earth Science Data sets that have been collected on a daily basis. This application uses a third-party, 3D, realtime, interactive game engine called Unity 3D to visualize the satellites and is accessible from a Web browser.
19. 3D Printing for Tissue Engineering
PubMed Central
Jia, Jia; Yao, Hai; Mei, Ying
2016-01-01
Tissue engineering aims to fabricate functional tissue for applications in regenerative medicine and drug testing. More recently, 3D printing has shown great promise in tissue fabrication with a structural control from micro- to macro-scale by using a layer-by-layer approach. Whether through scaffold-based or scaffold-free approaches, the standard for 3D printed tissue engineering constructs is to provide a biomimetic structural environment that facilitates tissue formation and promotes host tissue integration (e.g., cellular infiltration, vascularization, and active remodeling). This review will cover several approaches that have advanced the field of 3D printing through novel fabrication methods of tissue engineering constructs. It will also discuss the applications of synthetic and natural materials for 3D printing facilitated tissue fabrication. PMID:26869728
20. 3DSEM: A 3D microscopy dataset.
PubMed
Tafti, Ahmad P; Kirkpatrick, Andrew B; Holz, Jessica D; Owen, Heather A; Yu, Zeyun
2016-03-01
The Scanning Electron Microscope (SEM) as a 2D imaging instrument has been widely used in many scientific disciplines including biological, mechanical, and materials sciences to determine the surface attributes of microscopic objects. However the SEM micrographs still remain 2D images. To effectively measure and visualize the surface properties, we need to truly restore the 3D shape model from 2D SEM images. Having 3D surfaces would provide anatomic shape of micro-samples which allows for quantitative measurements and informative visualization of the specimens being investigated. The 3DSEM is a dataset for 3D microscopy vision which is freely available at [1] for any academic, educational, and research purposes. The dataset includes both 2D images and 3D reconstructed surfaces of several real microscopic samples.
1. 3D-printed bioanalytical devices.
PubMed
Bishop, Gregory W; Satterwhite-Warden, Jennifer E; Kadimisetty, Karteek; Rusling, James F
2016-07-15
While 3D printing technologies first appeared in the 1980s, prohibitive costs, limited materials, and the relatively small number of commercially available printers confined applications mainly to prototyping for manufacturing purposes. As technologies, printer cost, materials, and accessibility continue to improve, 3D printing has found widespread implementation in research and development in many disciplines due to ease-of-use and relatively fast design-to-object workflow. Several 3D printing techniques have been used to prepare devices such as milli- and microfluidic flow cells for analyses of cells and biomolecules as well as interfaces that enable bioanalytical measurements using cellphones. This review focuses on preparation and applications of 3D-printed bioanalytical devices. PMID:27250897
2. Nonlaser-based 3D surface imaging
SciTech Connect
Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J.
1994-11-15
3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.
3. 3-D Flyover Visualization of Veil Nebula
NASA Video Gallery
This 3-D visualization flies across a small portion of the Veil Nebula as photographed by the Hubble Space Telescope. This region is a small part of a huge expanding remnant from a star that explod...
4. Future Engineers 3-D Print Timelapse
NASA Video Gallery
NASA Challenges K-12 students to create a model of a container for space using 3-D modeling software. Astronauts need containers of all kinds - from advanced containers that can study fruit flies t...
5. Modeling Cellular Processes in 3-D
PubMed Central
Mogilner, Alex; Odde, David
2011-01-01
Summary Recent advances in photonic imaging and fluorescent protein technology offer unprecedented views of molecular space-time dynamics in living cells. At the same time, advances in computing hardware and software enable modeling of ever more complex systems, from global climate to cell division. As modeling and experiment become more closely integrated, we must address the issue of modeling cellular processes in 3-D. Here, we highlight recent advances related to 3-D modeling in cell biology. While some processes require full 3-D analysis, we suggest that others are more naturally described in 2-D or 1-D. Keeping the dimensionality as low as possible reduces computational time and makes models more intuitively comprehensible; however, the ability to test full 3-D models will build greater confidence in models generally and remains an important emerging area of cell biological modeling. PMID:22036197
6. 3D goes digital: from stereoscopy to modern 3D imaging techniques
Kerwien, N.
2014-11-01
In the 19th century, English physicist Charles Wheatstone discovered stereopsis, the basis for 3D perception. His construction of the first stereoscope established the foundation for stereoscopic 3D imaging. Since then, many optical instruments were influenced by these basic ideas. In recent decades, the advent of digital technologies revolutionized 3D imaging. Powerful readily available sensors and displays combined with efficient pre- or post-processing enable new methods for 3D imaging and applications. This paper draws an arc from basic concepts of 3D imaging to modern digital implementations, highlighting instructive examples from its 175 years of history.
7. Motif3D: Relating protein sequence motifs to 3D structure.
PubMed
Gaulton, Anna; Attwood, Teresa K
2003-07-01
Motif3D is a web-based protein structure viewer designed to allow sequence motifs, and in particular those contained in the fingerprints of the PRINTS database, to be visualised on three-dimensional (3D) structures. Additional functionality is provided for the rhodopsin-like G protein-coupled receptors, enabling fingerprint motifs of any of the receptors in this family to be mapped onto the single structure available, that of bovine rhodopsin. Motif3D can be used via the web interface available at: http://www.bioinf.man.ac.uk/dbbrowser/motif3d/motif3d.html.
8. Assessing 3d Photogrammetry Techniques in Craniometrics
Moshobane, M. C.; de Bruyn, P. J. N.; Bester, M. N.
2016-06-01
Morphometrics (the measurement of morphological features) has been revolutionized by the creation of new techniques to study how organismal shape co-varies with several factors such as ecophenotypy. Ecophenotypy refers to the divergence of phenotypes due to developmental changes induced by local environmental conditions, producing distinct ecophenotypes. None of the techniques hitherto utilized could explicitly address organismal shape in a complete biological form, i.e. three-dimensionally. This study investigates the use of the commercial software, Photomodeler Scanner® (PMSc®) three-dimensional (3D) modelling software to produce accurate and high-resolution 3D models. Henceforth, the modelling of Subantarctic fur seal (Arctocephalus tropicalis) and Antarctic fur seal (Arctocephalus gazella) skulls which could allow for 3D measurements. Using this method, sixteen accurate 3D skull models were produced and five metrics were determined. The 3D linear measurements were compared to measurements taken manually with a digital caliper. In addition, repetitive measurements were recorded by varying researchers to determine repeatability. To allow for comparison straight line measurements were taken with the software, assuming that close accord with all manually measured features would illustrate the model's accurate replication of reality. Measurements were not significantly different demonstrating that realistic 3D skull models can be successfully produced to provide a consistent basis for craniometrics, with the additional benefit of allowing non-linear measurements if required.
9. Exploring interaction with 3D volumetric displays
Grossman, Tovi; Wigdor, Daniel; Balakrishnan, Ravin
2005-03-01
Volumetric displays generate true volumetric 3D images by actually illuminating points in 3D space. As a result, viewing their contents is similar to viewing physical objects in the real world. These displays provide a 360 degree field of view, and do not require the user to wear hardware such as shutter glasses or head-trackers. These properties make them a promising alternative to traditional display systems for viewing imagery in 3D. Because these displays have only recently been made available commercially (e.g., www.actuality-systems.com), their current use tends to be limited to non-interactive output-only display devices. To take full advantage of the unique features of these displays, however, it would be desirable if the 3D data being displayed could be directly interacted with and manipulated. We investigate interaction techniques for volumetric display interfaces, through the development of an interactive 3D geometric model building application. While this application area itself presents many interesting challenges, our focus is on the interaction techniques that are likely generalizable to interactive applications for other domains. We explore a very direct style of interaction where the user interacts with the virtual data using direct finger manipulations on and around the enclosure surrounding the displayed 3D volumetric image.
10. Recording stereoscopic 3D neurosurgery with a head-mounted 3D camera system.
PubMed
Lee, Brian; Chen, Brian R; Chen, Beverly B; Lu, James Y; Giannotta, Steven L
2015-06-01
Stereoscopic three-dimensional (3D) imaging can present more information to the viewer and further enhance the learning experience over traditional two-dimensional (2D) video. Most 3D surgical videos are recorded from the operating microscope and only feature the crux, or the most important part of the surgery, leaving out other crucial parts of surgery including the opening, approach, and closing of the surgical site. In addition, many other surgeries including complex spine, trauma, and intensive care unit procedures are also rarely recorded. We describe and share our experience with a commercially available head-mounted stereoscopic 3D camera system to obtain stereoscopic 3D recordings of these seldom recorded aspects of neurosurgery. The strengths and limitations of using the GoPro(®) 3D system as a head-mounted stereoscopic 3D camera system in the operating room are reviewed in detail. Over the past several years, we have recorded in stereoscopic 3D over 50 cranial and spinal surgeries and created a library for education purposes. We have found the head-mounted stereoscopic 3D camera system to be a valuable asset to supplement 3D footage from a 3D microscope. We expect that these comprehensive 3D surgical videos will become an important facet of resident education and ultimately lead to improved patient care.
11. Extremely accurate sequential verification of RELAP5-3D
DOE PAGES
Mesina, George L.; Aumiller, David L.; Buschman, Francis X.
2015-11-19
Large computer programs like RELAP5-3D solve complex systems of governing, closure and special process equations to model the underlying physics of nuclear power plants. Further, these programs incorporate many other features for physics, input, output, data management, user-interaction, and post-processing. For software quality assurance, the code must be verified and validated before being released to users. For RELAP5-3D, verification and validation are restricted to nuclear power plant applications. Verification means ensuring that the program is built right by checking that it meets its design specifications, comparing coding to algorithms and equations and comparing calculations against analytical solutions and method ofmore » manufactured solutions. Sequential verification performs these comparisons initially, but thereafter only compares code calculations between consecutive code versions to demonstrate that no unintended changes have been introduced. Recently, an automated, highly accurate sequential verification method has been developed for RELAP5-3D. The method also provides to test that no unintended consequences result from code development in the following code capabilities: repeating a timestep advancement, continuing a run from a restart file, multiple cases in a single code execution, and modes of coupled/uncoupled operation. In conclusion, mathematical analyses of the adequacy of the checks used in the comparisons are provided.« less
12. Extremely accurate sequential verification of RELAP5-3D
SciTech Connect
Mesina, George L.; Aumiller, David L.; Buschman, Francis X.
2015-11-19
Large computer programs like RELAP5-3D solve complex systems of governing, closure and special process equations to model the underlying physics of nuclear power plants. Further, these programs incorporate many other features for physics, input, output, data management, user-interaction, and post-processing. For software quality assurance, the code must be verified and validated before being released to users. For RELAP5-3D, verification and validation are restricted to nuclear power plant applications. Verification means ensuring that the program is built right by checking that it meets its design specifications, comparing coding to algorithms and equations and comparing calculations against analytical solutions and method of manufactured solutions. Sequential verification performs these comparisons initially, but thereafter only compares code calculations between consecutive code versions to demonstrate that no unintended changes have been introduced. Recently, an automated, highly accurate sequential verification method has been developed for RELAP5-3D. The method also provides to test that no unintended consequences result from code development in the following code capabilities: repeating a timestep advancement, continuing a run from a restart file, multiple cases in a single code execution, and modes of coupled/uncoupled operation. In conclusion, mathematical analyses of the adequacy of the checks used in the comparisons are provided.
13. CFL3D, FUN3d, and NSU3D Contributions to the Fifth Drag Prediction Workshop
NASA Technical Reports Server (NTRS)
Park, Michael A.; Laflin, Kelly R.; Chaffin, Mark S.; Powell, Nicholas; Levy, David W.
2013-01-01
Results presented at the Fifth Drag Prediction Workshop using CFL3D, FUN3D, and NSU3D are described. These are calculations on the workshop provided grids and drag adapted grids. The NSU3D results have been updated to reflect an improvement to skin friction calculation on skewed grids. FUN3D results generated after the workshop are included for custom participant generated grids and a grid from a previous workshop. Uniform grid refinement at the design condition shows a tight grouping in calculated drag, where the variation in the pressure component of drag is larger than the skin friction component. At this design condition, A fine-grid drag value was predicted with a smaller drag adjoint adapted grid via tetrahedral adaption to a metric and mixed-element subdivision. The buffet study produced larger variation than the design case, which is attributed to large differences in the predicted side-of-body separation extent. Various modeling and discretization approaches had a strong impact on predicted side-of-body separation. This large wing root separation bubble was not observed in wind tunnel tests indicating that more work is necessary in modeling wing root juncture flows to predict experiments.
14. Self assembled structures for 3D integration
Three dimensional (3D) micro-scale structures attached to a silicon substrate have various applications in microelectronics. However, formation of 3D structures using conventional micro-fabrication techniques are not efficient and require precise control of processing parameters. Self assembly is a method for creating 3D structures that takes advantage of surface area minimization phenomena. Solder based self assembly (SBSA), the subject of this dissertation, uses solder as a facilitator in the formation of 3D structures from 2D patterns. Etching a sacrificial layer underneath a portion of the 2D pattern allows the solder reflow step to pull those areas out of the substrate plane resulting in a folded 3D structure. Initial studies using the SBSA method demonstrated low yields in the formation of five different polyhedra. The failures in folding were primarily attributed to nonuniform solder deposition on the underlying metal pads. The dip soldering method was analyzed and subsequently refined. A modified dip soldering process provided improved yield among the polyhedra. Solder bridging referred as joining of solder deposited on different metal patterns in an entity influenced the folding mechanism. In general, design parameters such as small gap-spacings and thick metal pads were found to favor solder bridging for all patterns studied. Two types of soldering: face and edge soldering were analyzed. Face soldering refers to the application of solder on the entire metal face. Edge soldering indicates application of solder only on the edges of the metal face. Mechanical grinding showed that face soldered SBSA structures were void free and robust in nature. In addition, the face soldered 3D structures provide a consistent heat resistant solder standoff height that serve as attachments in the integration of dissimilar electronic technologies. Face soldered 3D structures were developed on the underlying conducting channel to determine the thermo-electric reliability of
15. PLOT3D Export Tool for Tecplot
NASA Technical Reports Server (NTRS)
Alter, Stephen
2010-01-01
The PLOT3D export tool for Tecplot solves the problem of modified data being impossible to output for use by another computational science solver. The PLOT3D Exporter add-on enables the use of the most commonly available visualization tools to engineers for output of a standard format. The exportation of PLOT3D data from Tecplot has far reaching effects because it allows for grid and solution manipulation within a graphical user interface (GUI) that is easily customized with macro language-based and user-developed GUIs. The add-on also enables the use of Tecplot as an interpolation tool for solution conversion between different grids of different types. This one add-on enhances the functionality of Tecplot so significantly, it offers the ability to incorporate Tecplot into a general suite of tools for computational science applications as a 3D graphics engine for visualization of all data. Within the PLOT3D Export Add-on are several functions that enhance the operations and effectiveness of the add-on. Unlike Tecplot output functions, the PLOT3D Export Add-on enables the use of the zone selection dialog in Tecplot to choose which zones are to be written by offering three distinct options - output of active, inactive, or all zones (grid blocks). As the user modifies the zones to output with the zone selection dialog, the zones to be written are similarly updated. This enables the use of Tecplot to create multiple configurations of a geometry being analyzed. For example, if an aircraft is loaded with multiple deflections of flaps, by activating and deactivating different zones for a specific flap setting, new specific configurations of that aircraft can be easily generated by only writing out specific zones. Thus, if ten flap settings are loaded into Tecplot, the PLOT3D Export software can output ten different configurations, one for each flap setting.
16. Patient-specific dosimetry based on quantitative SPECT imaging and 3D-DFT convolution
SciTech Connect
Akabani, G.; Hawkins, W.G.; Eckblade, M.B.; Leichner, P.K.
1999-01-01
The objective of this study was to validate the use of a 3-D discrete Fourier Transform (3D-DFT) convolution method to carry out the dosimetry for I-131 for soft tissues in radioimmunotherapy procedures. To validate this convolution method, mathematical and physical phantoms were used as a basis of comparison with Monte Carlo transport (MCT) calculations which were carried out using the EGS4 system code. The mathematical phantom consisted of a sphere containing uniform and nonuniform activity distributions. The physical phantom consisted of a cylinder containing uniform and nonuniform activity distributions. Quantitative SPECT reconstruction was carried out using the Circular Harmonic Transform (CHT) algorithm.
17. A microfluidic device for 2D to 3D and 3D to 3D cell navigation
Shamloo, Amir; Amirifar, Leyla
2016-01-01
Microfluidic devices have received wide attention and shown great potential in the field of tissue engineering and regenerative medicine. Investigating cell response to various stimulations is much more accurate and comprehensive with the aid of microfluidic devices. In this study, we introduced a microfluidic device by which the matrix density as a mechanical property and the concentration profile of a biochemical factor as a chemical property could be altered. Our microfluidic device has a cell tank and a cell culture chamber to mimic both 2D to 3D and 3D to 3D migration of three types of cells. Fluid shear stress is negligible on the cells and a stable concentration gradient can be obtained by diffusion. The device was designed by a numerical simulation so that the uniformity of the concentration gradients throughout the cell culture chamber was obtained. Adult neural cells were cultured within this device and they showed different branching and axonal navigation phenotypes within varying nerve growth factor (NGF) concentration profiles. Neural stem cells were also cultured within varying collagen matrix densities while exposed to NGF concentrations and they experienced 3D to 3D collective migration. By generating vascular endothelial growth factor concentration gradients, adult human dermal microvascular endothelial cells also migrated in a 2D to 3D manner and formed a stable lumen within a specific collagen matrix density. It was observed that a minimum absolute concentration and concentration gradient were required to stimulate migration of all types of the cells. This device has the advantage of changing multiple parameters simultaneously and is expected to have wide applicability in cell studies.
18. Fish body surface data measurement based on 3D digital image correlation
Jiang, Ming; Qian, Chen; Yang, Wenkai
2016-01-01
To film the moving fish in the glass tank, light will be bent at the interface of air and glass, glass and water. Based on binocular stereo vision and refraction principle, we establish a mathematical model of 3D image correlation to reconstruct the 3D coordinates of samples in the water. Marking speckle in fish surface, a series of real-time speckle images of swimming fish will be obtained by two high-speed cameras, and instantaneous 3D shape, strain, displacement etc. of fish will be reconstructed.
19. A 3D acquisition system combination of structured-light scanning and shape from silhouette
Sun, Changku; Tao, Li; Wang, Peng; He, Li
2006-05-01
A robust and accurate three dimensional (3D) acquisition system is presented, which is a combination of structured-light scanning and shape from silhouette. Using common world coordinate system, two groups of point data can be integrated into the final complete 3D model without any integration and registration algorithm. The mathematics model of structured-light scanning is described in detail, and the shape from silhouette algorithm is introduced as well. The complete 3D model of a cup with a handle is obtained successfully by the proposed technique. At last the measurement on a ball bearing is performed, with the measurement precision better than 0.15 mm.
20. Nano-Composite Material Development for 3-D Printers
SciTech Connect
Satches, Michael Randolph
2015-12-01
Graphene possesses excellent mechanical properties with a tensile strength that may exceed 130 GPa, excellent electrical conductivity, and good thermal properties. Future nano-composites can leverage many of these material properties in an attempt to build designer materials for a broad range of applications. 3-D printing has also seen vast improvements in recent years that have allowed many companies and individuals to realize rapid prototyping for relatively low capital investment. This research sought to create a graphene reinforced, polymer matrix nano-composite that is viable in commercial 3D printer technology, study the effects of ultra-high loading percentages of graphene in polymer matrices and determine the functional upper limit for loading. Loadings varied from 5 wt. % to 50 wt. % graphene nanopowder loaded in Acrylonitrile Butadiene Styrene (ABS) matrices. Loaded sample were characterized for their mechanical properties using three point bending, tensile tests, as well as dynamic mechanical analysis.
1. RAG-3D: A search tool for RNA 3D substructures
DOE PAGES
Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar
2015-08-24
In this study, to address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D—a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool—designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally describedmore » in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding.« less
2. RAG-3D: A search tool for RNA 3D substructures
SciTech Connect
Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar
2015-08-24
In this study, to address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D—a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool—designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally described in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding.
3. RAG-3D: a search tool for RNA 3D substructures
PubMed Central
Zahran, Mai; Sevim Bayrak, Cigdem; Elmetwaly, Shereef; Schlick, Tamar
2015-01-01
To address many challenges in RNA structure/function prediction, the characterization of RNA's modular architectural units is required. Using the RNA-As-Graphs (RAG) database, we have previously explored the existence of secondary structure (2D) submotifs within larger RNA structures. Here we present RAG-3D—a dataset of RNA tertiary (3D) structures and substructures plus a web-based search tool—designed to exploit graph representations of RNAs for the goal of searching for similar 3D structural fragments. The objects in RAG-3D consist of 3D structures translated into 3D graphs, cataloged based on the connectivity between their secondary structure elements. Each graph is additionally described in terms of its subgraph building blocks. The RAG-3D search tool then compares a query RNA 3D structure to those in the database to obtain structurally similar structures and substructures. This comparison reveals conserved 3D RNA features and thus may suggest functional connections. Though RNA search programs based on similarity in sequence, 2D, and/or 3D structural elements are available, our graph-based search tool may be advantageous for illuminating similarities that are not obvious; using motifs rather than sequence space also reduces search times considerably. Ultimately, such substructuring could be useful for RNA 3D structure prediction, structure/function inference and inverse folding. PMID:26304547
4. ICER-3D Hyperspectral Image Compression Software
NASA Technical Reports Server (NTRS)
Xie, Hua; Kiely, Aaron; Klimesh, matthew; Aranki, Nazeeh
2010-01-01
Software has been developed to implement the ICER-3D algorithm. ICER-3D effects progressive, three-dimensional (3D), wavelet-based compression of hyperspectral images. If a compressed data stream is truncated, the progressive nature of the algorithm enables reconstruction of hyperspectral data at fidelity commensurate with the given data volume. The ICER-3D software is capable of providing either lossless or lossy compression, and incorporates an error-containment scheme to limit the effects of data loss during transmission. The compression algorithm, which was derived from the ICER image compression algorithm, includes wavelet-transform, context-modeling, and entropy coding subalgorithms. The 3D wavelet decomposition structure used by ICER-3D exploits correlations in all three dimensions of sets of hyperspectral image data, while facilitating elimination of spectral ringing artifacts, using a technique summarized in "Improving 3D Wavelet-Based Compression of Spectral Images" (NPO-41381), NASA Tech Briefs, Vol. 33, No. 3 (March 2009), page 7a. Correlation is further exploited by a context-modeling subalgorithm, which exploits spectral dependencies in the wavelet-transformed hyperspectral data, using an algorithm that is summarized in "Context Modeler for Wavelet Compression of Hyperspectral Images" (NPO-43239), which follows this article. An important feature of ICER-3D is a scheme for limiting the adverse effects of loss of data during transmission. In this scheme, as in the similar scheme used by ICER, the spatial-frequency domain is partitioned into rectangular error-containment regions. In ICER-3D, the partitions extend through all the wavelength bands. The data in each partition are compressed independently of those in the other partitions, so that loss or corruption of data from any partition does not affect the other partitions. Furthermore, because compression is progressive within each partition, when data are lost, any data from that partition received
5. 3D imaging: how to achieve highest accuracy
Luhmann, Thomas
2011-07-01
The generation of 3D information from images is a key technology in many different areas, e.g. in 3D modeling and representation of architectural or heritage objects, in human body motion tracking and scanning, in 3D scene analysis of traffic scenes, in industrial applications and many more. The basic concepts rely on mathematical representations of central perspective viewing as they are widely known from photogrammetry or computer vision approaches. The objectives of these methods differ, more or less, from high precision and well-structured measurements in (industrial) photogrammetry to fully-automated non-structured applications in computer vision. Accuracy and precision is a critical issue for the 3D measurement of industrial, engineering or medical objects. As state of the art, photogrammetric multi-view measurements achieve relative precisions in the order of 1:100000 to 1:200000, and relative accuracies with respect to retraceable lengths in the order of 1:50000 to 1:100000 of the largest object diameter. In order to obtain these figures a number of influencing parameters have to be optimized. These are, besides others: physical representation of object surface (targets, texture), illumination and light sources, imaging sensors, cameras and lenses, calibration strategies (camera model), orientation strategies (bundle adjustment), image processing of homologue features (target measurement, stereo and multi-image matching), representation of object or workpiece coordinate systems and object scale. The paper discusses the above mentioned parameters and offers strategies for obtaining highest accuracy in object space. Practical examples of high-quality stereo camera measurements and multi-image applications are used to prove the relevance of high accuracy in different applications, ranging from medical navigation to static and dynamic industrial measurements. In addition, standards for accuracy verifications are presented and demonstrated by practical examples
6. 3D Geological Model for "LUSI" - a Deep Geothermal System
Sohrabi, Reza; Jansen, Gunnar; Mazzini, Adriano; Galvan, Boris; Miller, Stephen A.
2016-04-01
Geothermal applications require the correct simulation of flow and heat transport processes in porous media, and many of these media, like deep volcanic hydrothermal systems, host a certain degree of fracturing. This work aims to understand the heat and fluid transport within a new-born sedimentary hosted geothermal system, termed Lusi, that began erupting in 2006 in East Java, Indonesia. Our goal is to develop conceptual and numerical models capable of simulating multiphase flow within large-scale fractured reservoirs such as the Lusi region, with fractures of arbitrary size, orientation and shape. Additionally, these models can also address a number of other applications, including Enhanced Geothermal Systems (EGS), CO2 sequestration (Carbon Capture and Storage CCS), and nuclear waste isolation. Fractured systems are ubiquitous, with a wide-range of lengths and scales, making difficult the development of a general model that can easily handle this complexity. We are developing a flexible continuum approach with an efficient, accurate numerical simulator based on an appropriate 3D geological model representing the structure of the deep geothermal reservoir. Using previous studies, borehole information and seismic data obtained in the framework of the Lusi Lab project (ERC grant n°308126), we present here the first 3D geological model of Lusi. This model is calculated using implicit 3D potential field or multi-potential fields, depending on the geological context and complexity. This method is based on geological pile containing the geological history of the area and relationship between geological bodies allowing automatic computation of intersections and volume reconstruction. Based on the 3D geological model, we developed a new mesh algorithm to create hexahedral octree meshes to transfer the structural geological information for 3D numerical simulations to quantify Thermal-Hydraulic-Mechanical-Chemical (THMC) physical processes.
7. T-HEMP3D user manual
SciTech Connect
Turner, D.
1983-08-01
The T-HEMP3D (Transportable HEMP3D) computer program is a derivative of the STEALTH three-dimensional thermodynamics code developed by Science Applications, Inc., under the direction of Ron Hofmann. STEALTH, in turn, is based entirely on the original HEMP3D code written at Lawrence Livermore National Laboratory. The primary advantage STEALTH has over its predecessors is that it was designed using modern structured design techniques, with rigorous programming standards enforced. This yields two benefits. First, the code is easily changeable; this is a necessity for a physics code used for research. The second benefit is that the code is easily transportable between different types of computers. The STEALTH program was transferred to LLNL under a cooperative development agreement. Changes were made primarily in three areas: material specification, coordinate generation, and the addition of sliding surface boundary conditions. The code was renamed T-HEMP3D to avoid confusion with other versions of STEALTH. This document summarizes the input to T-HEMP3D, as used at LLNL. It does not describe the physics simulated by the program, nor the numerical techniques employed. Furthermore, it does not describe the separate job steps of coordinate generation and post-processing, including graphical display of results. (WHK)
8. The importance of 3D dosimetry
Low, Daniel
2015-01-01
Radiation therapy has been getting progressively more complex for the past 20 years. Early radiation therapy techniques needed only basic dosimetry equipment; motorized water phantoms, ionization chambers, and basic radiographic film techniques. As intensity modulated radiation therapy and image guided therapy came into widespread practice, medical physicists were challenged with developing effective and efficient dose measurement techniques. The complex 3-dimensional (3D) nature of the dose distributions that were being delivered demanded the development of more quantitative and more thorough methods for dose measurement. The quality assurance vendors developed a wide array of multidetector arrays that have been enormously useful for measuring and characterizing dose distributions, and these have been made especially useful with the advent of 3D dose calculation systems based on the array measurements, as well as measurements made using film and portal imagers. Other vendors have been providing 3D calculations based on data from the linear accelerator or the record and verify system, providing thorough evaluation of the dose but lacking quality assurance (QA) of the dose delivery process, including machine calibration. The current state of 3D dosimetry is one of a state of flux. The vendors and professional associations are trying to determine the optimal balance between thorough QA, labor efficiency, and quantitation. This balance will take some time to reach, but a necessary component will be the 3D measurement and independent calculation of delivered radiation therapy dose distributions.
9. 3D Spray Droplet Distributions in Sneezes
Techet, Alexandra; Scharfman, Barry; Bourouiba, Lydia
2015-11-01
3D spray droplet clouds generated during human sneezing are investigated using the Synthetic Aperture Feature Extraction (SAFE) method, which relies on light field imaging (LFI) and synthetic aperture (SA) refocusing computational photographic techniques. An array of nine high-speed cameras are used to image sneeze droplets and tracked the droplets in 3D space and time (3D + T). An additional high-speed camera is utilized to track the motion of the head during sneezing. In the SAFE method, the raw images recorded by each camera in the array are preprocessed and binarized, simplifying post processing after image refocusing and enabling the extraction of feature sizes and positions in 3D + T. These binary images are refocused using either additive or multiplicative methods, combined with thresholding. Sneeze droplet centroids, radii, distributions and trajectories are determined and compared with existing data. The reconstructed 3D droplet centroids and radii enable a more complete understanding of the physical extent and fluid dynamics of sneeze ejecta. These measurements are important for understanding the infectious disease transmission potential of sneezes in various indoor environments.
10. 3D dynamic roadmapping for abdominal catheterizations.
PubMed
Bender, Frederik; Groher, Martin; Khamene, Ali; Wein, Wolfgang; Heibel, Tim Hauke; Navab, Nassir
2008-01-01
Despite rapid advances in interventional imaging, the navigation of a guide wire through abdominal vasculature remains, not only for novice radiologists, a difficult task. Since this navigation is mostly based on 2D fluoroscopic image sequences from one view, the process is slowed down significantly due to missing depth information and patient motion. We propose a novel approach for 3D dynamic roadmapping in deformable regions by predicting the location of the guide wire tip in a 3D vessel model from the tip's 2D location, respiratory motion analysis, and view geometry. In a first step, the method compensates for the apparent respiratory motion in 2D space before backprojecting the 2D guide wire tip into three dimensional space, using a given projection matrix. To countervail the error connected to the projection parameters and the motion compensation, as well as the ambiguity caused by vessel deformation, we establish a statistical framework, which computes a reliable estimate of the guide wire tip location within the 3D vessel model. With this 2D-to-3D transfer, the navigation can be performed from arbitrary viewing angles, disconnected from the static perspective view of the fluoroscopic sequence. Tests on a realistic breathing phantom and on synthetic data with a known ground truth clearly reveal the superiority of our approach compared to naive methods for 3D roadmapping. The concepts and information presented in this paper are based on research and are not commercially available. PMID:18982662
11. 3D bioprinting for engineering complex tissues.
PubMed
Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho
2016-01-01
Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies.
12. Shim3d Helmholtz Solution Package
2009-01-29
This suite of codes solves the Helmholtz Equation for the steady-state propagation of single-frequency electromagnetic radiation in an arbitrary 2D or 3D dielectric medium. Materials can be either transparent or absorptive (including metals) and are described entirely by their shape and complex dielectric constant. Dielectric boundaries are assumed to always fall on grid boundaries and the material within a single grid cell is considered to be uniform. Input to the problem is in the formmore » of a Dirichlet boundary condition on a single boundary, and may be either analytic (Gaussian) in shape, or a mode shape computed using a separate code (such as the included eigenmode solver vwave20), and written to a file. Solution is via the finite difference method using Jacobi iteration for 3D problems or direct matrix inversion for 2D problems. Note that 3D problems that include metals will require different iteration parameters than described in the above reference. For structures with curved boundaries not easily modeled on a rectangular grid, the auxillary codes helmholtz11(2D), helm3d (semivectoral), and helmv3d (full vectoral) are provided. For these codes the finite difference equations are specified on a topological regular triangular grid and solved using Jacobi iteration or direct matrix inversion as before. An automatic grid generator is supplied.« less
13. Full-color holographic 3D printer
Takano, Masami; Shigeta, Hiroaki; Nishihara, Takashi; Yamaguchi, Masahiro; Takahashi, Susumu; Ohyama, Nagaaki; Kobayashi, Akihiko; Iwata, Fujio
2003-05-01
A holographic 3D printer is a system that produces a direct hologram with full-parallax information using the 3-dimensional data of a subject from a computer. In this paper, we present a proposal for the reproduction of full-color images with the holographic 3D printer. In order to realize the 3-dimensional color image, we selected the 3 laser wavelength colors of red (λ=633nm), green (λ=533nm), and blue (λ=442nm), and we built a one-step optical system using a projection system and a liquid crystal display. The 3-dimensional color image is obtained by synthesizing in a 2D array the multiple exposure with these 3 wavelengths made on each 250mm elementary hologram, and moving recording medium on a x-y stage. For the natural color reproduction in the holographic 3D printer, we take the approach of the digital processing technique based on the color management technology. The matching between the input and output colors is performed by investigating first, the relation between the gray level transmittance of the LCD and the diffraction efficiency of the hologram and second, by measuring the color displayed by the hologram to establish a correlation. In our first experimental results a non-linear functional relation for single and multiple exposure of the three components were found. These results are the first step in the realization of a natural color 3D image produced by the holographic color 3D printer.
14. DYNA3D Code Practices and Developments
SciTech Connect
Lin, L.; Zywicz, E.; Raboin, P.
2000-04-21
DYNA3D is an explicit, finite element code developed to solve high rate dynamic simulations for problems of interest to the engineering mechanics community. The DYNA3D code has been under continuous development since 1976[1] by the Methods Development Group in the Mechanical Engineering Department of Lawrence Livermore National Laboratory. The pace of code development activities has substantially increased in the past five years, growing from one to between four and six code developers. This has necessitated the use of software tools such as CVS (Concurrent Versions System) to help manage multiple version updates. While on-line documentation with an Adobe PDF manual helps to communicate software developments, periodically a summary document describing recent changes and improvements in DYNA3D software is needed. The first part of this report describes issues surrounding software versions and source control. The remainder of this report details the major capability improvements since the last publicly released version of DYNA3D in 1996. Not included here are the many hundreds of bug corrections and minor enhancements, nor the development in DYNA3D between the manual release in 1993[2] and the public code release in 1996.
15. BEAMS3D Neutral Beam Injection Model
McMillan, Matthew; Lazerson, Samuel A.
2014-09-01
With the advent of applied 3D fields in Tokamaks and modern high performance stellarators, a need has arisen to address non-axisymmetric effects on neutral beam heating and fueling. We report on the development of a fully 3D neutral beam injection (NBI) model, BEAMS3D, which addresses this need by coupling 3D equilibria to a guiding center code capable of modeling neutral and charged particle trajectories across the separatrix and into the plasma core. Ionization, neutralization, charge-exchange, viscous slowing down, and pitch angle scattering are modeled with the ADAS atomic physics database. Elementary benchmark calculations are presented to verify the collisionless particle orbits, NBI model, frictional drag, and pitch angle scattering effects. A calculation of neutral beam heating in the NCSX device is performed, highlighting the capability of the code to handle 3D magnetic fields. Notice: this manuscript has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the US Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.
16. Lifting Object Detection Datasets into 3D.
PubMed
Carreira, Joao; Vicente, Sara; Agapito, Lourdes; Batista, Jorge
2016-07-01
While data has certainly taken the center stage in computer vision in recent years, it can still be difficult to obtain in certain scenarios. In particular, acquiring ground truth 3D shapes of objects pictured in 2D images remains a challenging feat and this has hampered progress in recognition-based object reconstruction from a single image. Here we propose to bypass previous solutions such as 3D scanning or manual design, that scale poorly, and instead populate object category detection datasets semi-automatically with dense, per-object 3D reconstructions, bootstrapped from:(i) class labels, (ii) ground truth figure-ground segmentations and (iii) a small set of keypoint annotations. Our proposed algorithm first estimates camera viewpoint using rigid structure-from-motion and then reconstructs object shapes by optimizing over visual hull proposals guided by loose within-class shape similarity assumptions. The visual hull sampling process attempts to intersect an object's projection cone with the cones of minimal subsets of other similar objects among those pictured from certain vantage points. We show that our method is able to produce convincing per-object 3D reconstructions and to accurately estimate cameras viewpoints on one of the most challenging existing object-category detection datasets, PASCAL VOC. We hope that our results will re-stimulate interest on joint object recognition and 3D reconstruction from a single image. PMID:27295458
17. Magnetic Properties of 3D Printed Toroids
Bollig, Lindsey; Otto, Austin; Hilpisch, Peter; Mowry, Greg; Nelson-Cheeseman, Brittany; Renewable Energy; Alternatives Lab (REAL) Team
Transformers are ubiquitous in electronics today. Although toroidal geometries perform most efficiently, transformers are traditionally made with rectangular cross-sections due to the lower manufacturing costs. Additive manufacturing techniques (3D printing) can easily achieve toroidal geometries by building up a part through a series of 2D layers. To get strong magnetic properties in a 3D printed transformer, a composite filament is used containing Fe dispersed in a polymer matrix. How the resulting 3D printed toroid responds to a magnetic field depends on two structural factors of the printed 2D layers: fill factor (planar density) and fill pattern. In this work, we investigate how the fill factor and fill pattern affect the magnetic properties of 3D printed toroids. The magnetic properties of the printed toroids are measured by a custom circuit that produces a hysteresis loop for each toroid. Toroids with various fill factors and fill patterns are compared to determine how these two factors can affect the magnetic field the toroid can produce. These 3D printed toroids can be used for numerous applications in order to increase the efficiency of transformers by making it possible for manufacturers to make a toroidal geometry.
18. 3D bioprinting for engineering complex tissues.
PubMed
Mandrycky, Christian; Wang, Zongjie; Kim, Keekyoung; Kim, Deok-Ho
2016-01-01
Bioprinting is a 3D fabrication technology used to precisely dispense cell-laden biomaterials for the construction of complex 3D functional living tissues or artificial organs. While still in its early stages, bioprinting strategies have demonstrated their potential use in regenerative medicine to generate a variety of transplantable tissues, including skin, cartilage, and bone. However, current bioprinting approaches still have technical challenges in terms of high-resolution cell deposition, controlled cell distributions, vascularization, and innervation within complex 3D tissues. While no one-size-fits-all approach to bioprinting has emerged, it remains an on-demand, versatile fabrication technique that may address the growing organ shortage as well as provide a high-throughput method for cell patterning at the micrometer scale for broad biomedical engineering applications. In this review, we introduce the basic principles, materials, integration strategies and applications of bioprinting. We also discuss the recent developments, current challenges and future prospects of 3D bioprinting for engineering complex tissues. Combined with recent advances in human pluripotent stem cell technologies, 3D-bioprinted tissue models could serve as an enabling platform for high-throughput predictive drug screening and more effective regenerative therapies. PMID:26724184
19. 3D culture for cardiac cells.
PubMed
Zuppinger, Christian
2016-07-01
This review discusses historical milestones, recent developments and challenges in the area of 3D culture models with cardiovascular cell types. Expectations in this area have been raised in recent years, but more relevant in vitro research, more accurate drug testing results, reliable disease models and insights leading to bioartificial organs are expected from the transition to 3D cell culture. However, the construction of organ-like cardiac 3D models currently remains a difficult challenge. The heart consists of highly differentiated cells in an intricate arrangement.Furthermore, electrical “wiring”, a vascular system and multiple cell types act in concert to respond to the rapidly changing demands of the body. Although cardiovascular 3D culture models have been predominantly developed for regenerative medicine in the past, their use in drug screening and for disease models has become more popular recently. Many sophisticated 3D culture models are currently being developed in this dynamic area of life science. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
20. Miniaturized 3D microscope imaging system
Lan, Yung-Sung; Chang, Chir-Weei; Sung, Hsin-Yueh; Wang, Yen-Chang; Chang, Cheng-Yi
2015-05-01
We designed and assembled a portable 3-D miniature microscopic image system with the size of 35x35x105 mm3 . By integrating a microlens array (MLA) into the optical train of a handheld microscope, the biological specimen's image will be captured for ease of use in a single shot. With the light field raw data and program, the focal plane can be changed digitally and the 3-D image can be reconstructed after the image was taken. To localize an object in a 3-D volume, an automated data analysis algorithm to precisely distinguish profundity position is needed. The ability to create focal stacks from a single image allows moving or specimens to be recorded. Applying light field microscope algorithm to these focal stacks, a set of cross sections will be produced, which can be visualized using 3-D rendering. Furthermore, we have developed a series of design rules in order to enhance the pixel using efficiency and reduce the crosstalk between each microlens for obtain good image quality. In this paper, we demonstrate a handheld light field microscope (HLFM) to distinguish two different color fluorescence particles separated by a cover glass in a 600um range, show its focal stacks, and 3-D position.
1. 3D optical measuring technologies and systems
Chugui, Yuri V.
2005-02-01
The results of the R & D activity of TDI SIE SB RAS in the field of the 3D optical measuring technologies and systems for noncontact 3D optical dimensional inspection applied to atomic and railway industry safety problems are presented. This activity includes investigations of diffraction phenomena on some 3D objects, using the original constructive calculation method. The efficient algorithms for precise determining the transverse and longitudinal sizes of 3D objects of constant thickness by diffraction method, peculiarities on formation of the shadow and images of the typical elements of the extended objects were suggested. Ensuring the safety of nuclear reactors and running trains as well as their high exploitation reliability requires a 100% noncontact precise inspection of geometrical parameters of their components. To solve this problem we have developed methods and produced the technical vision measuring systems LMM, CONTROL, PROFIL, and technologies for noncontact 3D dimensional inspection of grid spacers and fuel elements for the nuclear reactor VVER-1000 and VVER-440, as well as automatic laser diagnostic COMPLEX for noncontact inspection of geometric parameters of running freight car wheel pairs. The performances of these systems and the results of industrial testing are presented and discussed. The created devices are in pilot operation at Atomic and Railway Companies.
2. Utilising a Collaborative Macro-Script to Enhance Student Engagement: A Mixed Method Study in a 3D Virtual Environment
ERIC Educational Resources Information Center
Bouta, Hara; Retalis, Symeon; Paraskeva, Fotini
2012-01-01
This study examines the effect of using an online 3D virtual environment in teaching Mathematics in Primary Education. In particular, it explores the extent to which student engagement--behavioral, affective and cognitive--is fostered by such tools in order to enhance collaborative learning. For the study we used a purpose-created 3D virtual…
3. Control of thermal balance by a liquid circulating garment based on a mathematical representation of the human thermoregulatory system. Ph.D. Thesis - California Univ., Berkeley
NASA Technical Reports Server (NTRS)
Kuznetz, L. H.
1976-01-01
Test data and a mathematical model of the human thermoregulatory system were used to investigate control of thermal balance by means of a liquid circulating garment (LCG). The test data were derived from five series of experiments in which environmental and metabolic conditions were varied parametrically as a function of several independent variables, including LCG flowrate, LCG inlet temperature, net environmental heat exchange, surrounding gas ventilation rate, ambient pressure, metabolic rate, and subjective/obligatory cooling control. The resultant data were used to relate skin temperature to LCG water temperature and flowrate, to assess a thermal comfort band, to demonstrate the relationship between metabolic rate and LCG heat dissipation, and so forth. The usefulness of the mathematical model as a tool for data interpretation and for generation of trends and relationships among the various physiological parameters was also investigated and verified.
4. 3D Simulation: Microgravity Environments and Applications
NASA Technical Reports Server (NTRS)
Hunter, Steve L.; Dischinger, Charles; Estes, Samantha; Parker, Nelson C. (Technical Monitor)
2001-01-01
Most, if not all, 3-D and Virtual Reality (VR) software programs are designed for one-G gravity applications. Space environments simulations require gravity effects of one one-thousandth to one one-million of that of the Earth's surface (10(exp -3) - 10(exp -6) G), thus one must be able to generate simulations that replicate those microgravity effects upon simulated astronauts. Unfortunately, the software programs utilized by the National Aeronautical and Space Administration does not have the ability to readily neutralize the one-G gravity effect. This pre-programmed situation causes the engineer or analysis difficulty during micro-gravity simulations. Therefore, microgravity simulations require special techniques or additional code in order to apply the power of 3D graphic simulation to space related applications. This paper discusses the problem and possible solutions to allow microgravity 3-D/VR simulations to be completed successfully without program code modifications.
5. 3D differential phase contrast microscopy
Chen, Michael; Tian, Lei; Waller, Laura
2016-03-01
We demonstrate three-dimensional (3D) optical phase and amplitude reconstruction based on coded source illumination using a programmable LED array. Multiple stacks of images along the optical axis are computed from recorded intensities captured by multiple images under off-axis illumination. Based on the first Born approximation, a linear differential phase contrast (DPC) model is built between 3D complex index of refraction and the intensity stacks. Therefore, 3D volume reconstruction can be achieved via a fast inversion method, without the intermediate 2D phase retrieval step. Our system employs spatially partially coherent illumination, so the transverse resolution achieves twice the NA of coherent systems, while axial resolution is also improved 2× as compared to holographic imaging.
6. The CIFIST 3D model atmosphere grid.
Ludwig, H.-G.; Caffau, E.; Steffen, M.; Freytag, B.; Bonifacio, P.; Kučinskas, A.
Grids of stellar atmosphere models and associated synthetic spectra are numerical products which have a large impact in astronomy due to their ubiquitous application in the interpretation of radiation from individual stars and stellar populations. 3D model atmospheres are now on the verge of becoming generally available for a wide range of stellar atmospheric parameters. We report on efforts to develop a grid of 3D model atmospheres for late-type stars within the CIFIST Team at Paris Observatory. The substantial demands in computational and human labor for the model production and post-processing render this apparently mundane task a challenging logistic exercise. At the moment the CIFIST grid comprises 77 3D model atmospheres with emphasis on dwarfs of solar and sub-solar metallicities. While the model production is still ongoing, first applications are already worked upon by the CIFIST Team and collaborators.
7. 3D Printed Multimaterial Microfluidic Valve.
PubMed
Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri
2016-01-01
We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics.
8. Simnple, portable, 3-D projection routine
SciTech Connect
Wagner, J.S.
1987-04-01
A 3-D projection routine is presented for use in computer graphics applications. The routine is simple enough to be considered portable, and easily modified for special problems. There is often the need to draw three-dimensional objects on a two-dimensional plotting surface. For the object to appear realistic, perspective effects must be included that allow near objects to appear larger than distant objects. Several 3-D projection routines are commercially available, but they are proprietary, not portable, and not easily changed by the user. Most are restricted to surfaces that are functions of two variables. This makes them unsuitable for viewing physical objects such as accelerator prototypes or propagating beams. This report develops a very simple algorithm for 3-D projections; the core routine is only 39 FORTRAN lines long. It can be easily modified for special problems. Software dependent calls are confined to simple drivers that can be exchanged when different plotting software packages are used.
9. Ames Lab 101: 3D Metals Printer
SciTech Connect
Ott, Ryan
2014-02-13
To meet one of the biggest energy challenges of the 21st century - finding alternatives to rare-earth elements and other critical materials - scientists will need new and advanced tools. The Critical Materials Institute at the U.S. Department of Energy's Ames Laboratory has a new one: a 3D printer for metals research. 3D printing technology, which has captured the imagination of both industry and consumers, enables ideas to move quickly from the initial design phase to final form using materials including polymers, ceramics, paper and even food. But the Critical Materials Institute (CMI) will apply the advantages of the 3D printing process in a unique way: for materials discovery.
10. 3D Printed Multimaterial Microfluidic Valve
PubMed Central
Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri
2016-01-01
We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809
11. Structured light field 3D imaging.
PubMed
Cai, Zewei; Liu, Xiaoli; Peng, Xiang; Yin, Yongkai; Li, Ameng; Wu, Jiachen; Gao, Bruce Z
2016-09-01
In this paper, we propose a method by means of light field imaging under structured illumination to deal with high dynamic range 3D imaging. Fringe patterns are projected onto a scene and modulated by the scene depth then a structured light field is detected using light field recording devices. The structured light field contains information about ray direction and phase-encoded depth, via which the scene depth can be estimated from different directions. The multidirectional depth estimation can achieve high dynamic 3D imaging effectively. We analyzed and derived the phase-depth mapping in the structured light field and then proposed a flexible ray-based calibration approach to determine the independent mapping coefficients for each ray. Experimental results demonstrated the validity of the proposed method to perform high-quality 3D imaging for highly and lowly reflective surfaces. PMID:27607639
12. 3D-printed microfluidic devices.
PubMed
Amin, Reza; Knowlton, Stephanie; Hart, Alexander; Yenilmez, Bekir; Ghaderinezhad, Fariba; Katebifar, Sara; Messina, Michael; Khademhosseini, Ali; Tasoglu, Savas
2016-06-20
Microfluidics is a flourishing field, enabling a wide range of biochemical and clinical applications such as cancer screening, micro-physiological system engineering, high-throughput drug testing, and point-of-care diagnostics. However, fabrication of microfluidic devices is often complicated, time consuming, and requires expensive equipment and sophisticated cleanroom facilities. Three-dimensional (3D) printing presents a promising alternative to traditional techniques such as lithography and PDMS-glass bonding, not only by enabling rapid design iterations in the development stage, but also by reducing the costs associated with institutional infrastructure, equipment installation, maintenance, and physical space. With the recent advancements in 3D printing technologies, highly complex microfluidic devices can be fabricated via single-step, rapid, and cost-effective protocols, making microfluidics more accessible to users. In this review, we discuss a broad range of approaches for the application of 3D printing technology to fabrication of micro-scale lab-on-a-chip devices.
13. 3D Printed Multimaterial Microfluidic Valve.
PubMed
Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri
2016-01-01
We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809
14. 3-D Mesh Generation Nonlinear Systems
SciTech Connect
Christon, M. A.; Dovey, D.; Stillman, D. W.; Hallquist, J. O.; Rainsberger, R. B
1994-04-07
INGRID is a general-purpose, three-dimensional mesh generator developed for use with finite element, nonlinear, structural dynamics codes. INGRID generates the large and complex input data files for DYNA3D, NIKE3D, FACET, and TOPAZ3D. One of the greatest advantages of INGRID is that virtually any shape can be described without resorting to wedge elements, tetrahedrons, triangular elements or highly distorted quadrilateral or hexahedral elements. Other capabilities available are in the areas of geometry and graphics. Exact surface equations and surface intersections considerably improve the ability to deal with accurate models, and a hidden line graphics algorithm is included which is efficient on the most complicated meshes. The primary new capability is associated with the boundary conditions, loads, and material properties required by nonlinear mechanics programs. Commands have been designed for each case to minimize user effort. This is particularly important since special processing is almost always required for each load or boundary condition.
15. 3D holoscopic video imaging system
Steurer, Johannes H.; Pesch, Matthias; Hahne, Christopher
2012-03-01
Since many years, integral imaging has been discussed as a technique to overcome the limitations of standard still photography imaging systems where a three-dimensional scene is irrevocably projected onto two dimensions. With the success of 3D stereoscopic movies, a huge interest in capturing three-dimensional motion picture scenes has been generated. In this paper, we present a test bench integral imaging camera system aiming to tailor the methods of light field imaging towards capturing integral 3D motion picture content. We estimate the hardware requirements needed to generate high quality 3D holoscopic images and show a prototype camera setup that allows us to study these requirements using existing technology. The necessary steps that are involved in the calibration of the system as well as the technique of generating human readable holoscopic images from the recorded data are discussed.
16. 3D face analysis for demographic biometrics
SciTech Connect
Tokola, Ryan A; Mikkilineni, Aravind K; Boehnen, Chris Bensing
2015-01-01
Despite being increasingly easy to acquire, 3D data is rarely used for face-based biometrics applications beyond identification. Recent work in image-based demographic biometrics has enjoyed much success, but these approaches suffer from the well-known limitations of 2D representations, particularly variations in illumination, texture, and pose, as well as a fundamental inability to describe 3D shape. This paper shows that simple 3D shape features in a face-based coordinate system are capable of representing many biometric attributes without problem-specific models or specialized domain knowledge. The same feature vector achieves impressive results for problems as diverse as age estimation, gender classification, and race classification.
17. Ames Lab 101: 3D Metals Printer
ScienceCinema
Ott, Ryan
2016-07-12
To meet one of the biggest energy challenges of the 21st century - finding alternatives to rare-earth elements and other critical materials - scientists will need new and advanced tools. The Critical Materials Institute at the U.S. Department of Energy's Ames Laboratory has a new one: a 3D printer for metals research. 3D printing technology, which has captured the imagination of both industry and consumers, enables ideas to move quickly from the initial design phase to final form using materials including polymers, ceramics, paper and even food. But the Critical Materials Institute (CMI) will apply the advantages of the 3D printing process in a unique way: for materials discovery.
18. Real-time monitoring of 3D cell culture using a 3D capacitance biosensor.
PubMed
Lee, Sun-Mi; Han, Nalae; Lee, Rimi; Choi, In-Hong; Park, Yong-Beom; Shin, Jeon-Soo; Yoo, Kyung-Hwa
2016-03-15
Three-dimensional (3D) cell cultures have recently received attention because they represent a more physiologically relevant environment compared to conventional two-dimensional (2D) cell cultures. However, 2D-based imaging techniques or cell sensors are insufficient for real-time monitoring of cellular behavior in 3D cell culture. Here, we report investigations conducted with a 3D capacitance cell sensor consisting of vertically aligned pairs of electrodes. When GFP-expressing human breast cancer cells (GFP-MCF-7) encapsulated in alginate hydrogel were cultured in a 3D cell culture system, cellular activities, such as cell proliferation and apoptosis at different heights, could be monitored non-invasively and in real-time by measuring the change in capacitance with the 3D capacitance sensor. Moreover, we were able to monitor cell migration of human mesenchymal stem cells (hMSCs) with our 3D capacitance sensor.
19. 3D scene reconstruction based on 3D laser point cloud combining UAV images
Liu, Huiyun; Yan, Yangyang; Zhang, Xitong; Wu, Zhenzhen
2016-03-01
It is a big challenge capturing and modeling 3D information of the built environment. A number of techniques and technologies are now in use. These include GPS, and photogrammetric application and also remote sensing applications. The experiment uses multi-source data fusion technology for 3D scene reconstruction based on the principle of 3D laser scanning technology, which uses the laser point cloud data as the basis and Digital Ortho-photo Map as an auxiliary, uses 3DsMAX software as a basic tool for building three-dimensional scene reconstruction. The article includes data acquisition, data preprocessing, 3D scene construction. The results show that the 3D scene has better truthfulness, and the accuracy of the scene meet the need of 3D scene construction.
20. 3D whiteboard: collaborative sketching with 3D-tracked smart phones
Lue, James; Schulze, Jürgen P.
2014-02-01
We present the results of our investigation of the feasibility of a new approach for collaborative drawing in 3D, based on Android smart phones. Our approach utilizes a number of fiduciary markers, placed in the working area where they can be seen by the smart phones' cameras, in order to estimate the pose of each phone in the room. Our prototype allows two users to draw 3D objects with their smart phones by moving their phones around in 3D space. For example, 3D lines are drawn by recording the path of the phone as it is moved around in 3D space, drawing line segments on the screen along the way. Each user can see the virtual drawing space on their smart phones' displays, as if the display was a window into this space. Besides lines, our prototype application also supports 3D geometry creation, geometry transformation operations, and it shows the location of the other user's phone.
1. Real-time monitoring of 3D cell culture using a 3D capacitance biosensor.
PubMed
Lee, Sun-Mi; Han, Nalae; Lee, Rimi; Choi, In-Hong; Park, Yong-Beom; Shin, Jeon-Soo; Yoo, Kyung-Hwa
2016-03-15
Three-dimensional (3D) cell cultures have recently received attention because they represent a more physiologically relevant environment compared to conventional two-dimensional (2D) cell cultures. However, 2D-based imaging techniques or cell sensors are insufficient for real-time monitoring of cellular behavior in 3D cell culture. Here, we report investigations conducted with a 3D capacitance cell sensor consisting of vertically aligned pairs of electrodes. When GFP-expressing human breast cancer cells (GFP-MCF-7) encapsulated in alginate hydrogel were cultured in a 3D cell culture system, cellular activities, such as cell proliferation and apoptosis at different heights, could be monitored non-invasively and in real-time by measuring the change in capacitance with the 3D capacitance sensor. Moreover, we were able to monitor cell migration of human mesenchymal stem cells (hMSCs) with our 3D capacitance sensor. PMID:26386332
2. Spatial watermarking of 3D triangle meshes
Cayre, Francois; Macq, Benoit M. M.
2001-12-01
Although it is obvious that watermarking has become of great interest in protecting audio, videos, and still pictures, few work has been done considering 3D meshes. We propose a new method for watermarking 3D triangle meshes. This method embeds the watermark as triangles deformations. The list of watermarked triangles is obtained through a similar way to the one used in the TSPS (Triangle Strip Peeling Sequence) method. Unlike TSPS, our method is automatic and more secure. We also show that it is reversible.
3. Acquisition and applications of 3D images
Sterian, Paul; Mocanu, Elena
2007-08-01
The moiré fringes method and their analysis up to medical and entertainment applications are discussed in this paper. We describe the procedure of capturing 3D images with an Inspeck Camera that is a real-time 3D shape acquisition system based on structured light techniques. The method is a high-resolution one. After processing the images, using computer, we can use the data for creating laser fashionable objects by engraving them with a Q-switched Nd:YAG. In medical field we mention the plastic surgery and the replacement of X-Ray especially in pediatric use.
4. Superplastic forming using NIKE3D
SciTech Connect
Puso, M.
1996-12-04
The superplastic forming process requires careful control of strain rates in order to avoid strain localizations. A load scheduler was developed and implemented into the nonlinear finite element code NIKE3D to provide strain rate control during forming simulation and process schedule output. Often the sheets being formed in SPF are very thin such that less expensive membrane elements can be used as opposed to shell elements. A large strain membrane element was implemented into NIKE3D to assist in SPF process modeling.
5. The Galicia 3D experiment: an Introduction.
Reston, Timothy; Martinez Loriente, Sara; Holroyd, Luke; Merry, Tobias; Sawyer, Dale; Morgan, Julia; Jordan, Brian; Tesi Sanjurjo, Mari; Alexanian, Ara; Shillington, Donna; Gibson, James; Minshull, Tim; Karplus, Marianne; Bayracki, Gaye; Davy, Richard; Klaeschen, Dirk; Papenberg, Cord; Ranero, Cesar; Perez-Gussinye, Marta; Martinez, Miguel
2014-05-01
In June and July 2013, scientists from 8 institutions took part in the Galicia 3D seismic experiment, the first ever crustal -scale academic 3D MCS survey over a rifted margin. The aim was to determine the 3D structure of a critical portion of the west Galicia rifted margin. At this margin, well-defined tilted fault blocks, bound by west-dipping faults and capped by synrift sediments are underlain by a bright reflection, undulating on time sections, termed the S reflector and thought to represent a major detachment fault of some kind. Moving west, the crust thins to zero thickness and mantle is unroofed, as evidence by the "Peridotite Ridge" first reported at this margin, but since observed at many other magma-poor margins. By imaging such a margin in detail, the experiment aimed to resolve the processes controlling crustal thinning and mantle unroofing at a type example magma poor margin. The experiment set out to collect several key datasets: a 3D seismic reflection volume measuring ~20x64km and extending down to ~14s TWT, a 3D ocean bottom seismometer dataset suitable for full wavefield inversion (the recording of the complete 3D seismic shots by 70 ocean bottom instruments), the "mirror imaging" of the crust using the same grid of OBS, a single 2D combined reflection/refraction profile extending to the west to determine the transition from unroofed mantle to true oceanic crust, and the seismic imaging of the water column, calibrated by regular deployment of XBTs to measure the temperature structure of the water column. We collected 1280 km2 of seismic reflection data, consisting of 136533 shots recorded on 1920 channels, producing 260 million seismic traces, each ~ 14s long. This adds up to ~ 8 terabytes of data, representing, we believe, the largest ever academic 3D MCS survey in terms of both the area covered and the volume of data. The OBS deployment was the largest ever within an academic 3D survey.
6. 3D Modeling Engine Representation Summary Report
SciTech Connect
Steven Prescott; Ramprasad Sampath; Curtis Smith; Timothy Yang
2014-09-01
Computers have been used for 3D modeling and simulation, but only recently have computational resources been able to give realistic results in a reasonable time frame for large complex models. This summary report addressed the methods, techniques, and resources used to develop a 3D modeling engine to represent risk analysis simulation for advanced small modular reactor structures and components. The simulations done for this evaluation were focused on external events, specifically tsunami floods, for a hypothetical nuclear power facility on a coastline.
7. Immersive 3D geovisualisation in higher education
Philips, Andrea; Walz, Ariane; Bergner, Andreas; Graeff, Thomas; Heistermann, Maik; Kienzler, Sarah; Korup, Oliver; Lipp, Torsten; Schwanghart, Wolfgang; Zeilinger, Gerold
2014-05-01
Through geovisualisation we explore spatial data, we analyse it towards a specific questions, we synthesise results, and we present and communicate them to a specific audience (MacEachren & Kraak 1997). After centuries of paper maps, the means to represent and visualise our physical environment and its abstract qualities have changed dramatically since the 1990s - and accordingly the methods how to use geovisualisation in teaching. Whereas some people might still consider the traditional classroom as ideal setting for teaching and learning geographic relationships and its mapping, we used a 3D CAVE (computer-animated virtual environment) as environment for a problem-oriented learning project called "GEOSimulator". Focussing on this project, we empirically investigated, if such a technological advance like the CAVE make 3D visualisation, including 3D geovisualisation, not only an important tool for businesses (Abulrub et al. 2012) and for the public (Wissen et al. 2008), but also for educational purposes, for which it had hardly been used yet. The 3D CAVE is a three-sided visualisation platform, that allows for immersive and stereoscopic visualisation of observed and simulated spatial data. We examined the benefits of immersive 3D visualisation for geographic research and education and synthesized three fundamental technology-based visual aspects: First, the conception and comprehension of space and location does not need to be generated, but is instantaneously and intuitively present through stereoscopy. Second, optical immersion into virtual reality strengthens this spatial perception which is in particular important for complex 3D geometries. And third, a significant benefit is interactivity, which is enhanced through immersion and allows for multi-discursive and dynamic data exploration and knowledge transfer. Based on our problem-oriented learning project, which concentrates on a case study on flood risk management at the Wilde Weisseritz in Germany, a river
8. 3D printed diffractive terahertz lenses.
PubMed
Furlan, Walter D; Ferrando, Vicente; Monsoriu, Juan A; Zagrajek, Przemysław; Czerwińska, Elżbieta; Szustakowski, Mieczysław
2016-04-15
A 3D printer was used to realize custom-made diffractive THz lenses. After testing several materials, phase binary lenses with periodic and aperiodic radial profiles were designed and constructed in polyamide material to work at 0.625 THz. The nonconventional focusing properties of such lenses were assessed by computing and measuring their axial point spread function (PSF). Our results demonstrate that inexpensive 3D printed THz diffractive lenses can be reliably used in focusing and imaging THz systems. Diffractive THz lenses with unprecedented features, such as extended depth of focus or bifocalization, have been demonstrated. PMID:27082335
9. Recent developments in DFD (depth-fused 3D) display and arc 3D display
Suyama, Shiro; Yamamoto, Hirotsugu
2015-05-01
We will report our recent developments in DFD (Depth-fused 3D) display and arc 3D display, both of which have smooth movement parallax. Firstly, fatigueless DFD display, composed of only two layered displays with a gap, has continuous perceived depth by changing luminance ratio between two images. Two new methods, called "Edge-based DFD display" and "Deep DFD display", have been proposed in order to solve two severe problems of viewing angle and perceived depth limitations. Edge-based DFD display, layered by original 2D image and its edge part with a gap, can expand the DFD viewing angle limitation both in 2D and 3D perception. Deep DFD display can enlarge the DFD image depth by modulating spatial frequencies of front and rear images. Secondly, Arc 3D display can provide floating 3D images behind or in front of the display by illuminating many arc-shaped directional scattering sources, for example, arcshaped scratches on a flat board. Curved Arc 3D display, composed of many directional scattering sources on a curved surface, can provide a peculiar 3D image, for example, a floating image in the cylindrical bottle. The new active device has been proposed for switching arc 3D images by using the tips of dual-frequency liquid-crystal prisms as directional scattering sources. Directional scattering can be switched on/off by changing liquid-crystal refractive index, resulting in switching of arc 3D image.
10. Innovations in 3D printing: a 3D overview from optics to organs.
PubMed
Schubert, Carl; van Langeveld, Mark C; Donoso, Larry A
2014-02-01
3D printing is a method of manufacturing in which materials, such as plastic or metal, are deposited onto one another in layers to produce a three dimensional object, such as a pair of eye glasses or other 3D objects. This process contrasts with traditional ink-based printers which produce a two dimensional object (ink on paper). To date, 3D printing has primarily been used in engineering to create engineering prototypes. However, recent advances in printing materials have now enabled 3D printers to make objects that are comparable with traditionally manufactured items. In contrast with conventional printers, 3D printing has the potential to enable mass customisation of goods on a large scale and has relevance in medicine including ophthalmology. 3D printing has already been proved viable in several medical applications including the manufacture of eyeglasses, custom prosthetic devices and dental implants. In this review, we discuss the potential for 3D printing to revolutionise manufacturing in the same way as the printing press revolutionised conventional printing. The applications and limitations of 3D printing are discussed; the production process is demonstrated by producing a set of eyeglass frames from 3D blueprints. PMID:24288392
11. Innovations in 3D printing: a 3D overview from optics to organs.
PubMed
Schubert, Carl; van Langeveld, Mark C; Donoso, Larry A
2014-02-01
3D printing is a method of manufacturing in which materials, such as plastic or metal, are deposited onto one another in layers to produce a three dimensional object, such as a pair of eye glasses or other 3D objects. This process contrasts with traditional ink-based printers which produce a two dimensional object (ink on paper). To date, 3D printing has primarily been used in engineering to create engineering prototypes. However, recent advances in printing materials have now enabled 3D printers to make objects that are comparable with traditionally manufactured items. In contrast with conventional printers, 3D printing has the potential to enable mass customisation of goods on a large scale and has relevance in medicine including ophthalmology. 3D printing has already been proved viable in several medical applications including the manufacture of eyeglasses, custom prosthetic devices and dental implants. In this review, we discuss the potential for 3D printing to revolutionise manufacturing in the same way as the printing press revolutionised conventional printing. The applications and limitations of 3D printing are discussed; the production process is demonstrated by producing a set of eyeglass frames from 3D blueprints.
12. The EISCAT_3D Science Case
Tjulin, A.; Mann, I.; McCrea, I.; Aikio, A. T.
2013-05-01
EISCAT_3D will be a world-leading international research infrastructure using the incoherent scatter technique to study the atmosphere in the Fenno-Scandinavian Arctic and to investigate how the Earth's atmosphere is coupled to space. The EISCAT_3D phased-array multistatic radar system will be operated by EISCAT Scientific Association and thus be an integral part of an organisation that has successfully been running incoherent scatter radars for more than thirty years. The baseline design of the radar system contains a core site with transmitting and receiving capabilities located close to the intersection of the Swedish, Norwegian and Finnish borders and five receiving sites located within 50 to 250 km from the core. The EISCAT_3D project is currently in its Preparatory Phase and can smoothly transit into implementation in 2014, provided sufficient funding. Construction can start 2016 and first operations in 2018. The EISCAT_3D Science Case is prepared as part of the Preparatory Phase. It is regularly updated with annual new releases, and it aims at being a common document for the whole future EISCAT_3D user community. The areas covered by the Science Case are atmospheric physics and global change; space and plasma physics; solar system research; space weather and service applications; and radar techniques, new methods for coding and analysis. Two of the aims for EISCAT_3D are to understand the ways natural variability in the upper atmosphere, imposed by the Sun-Earth system, can influence the middle and lower atmosphere, and to improve the predictivity of atmospheric models by providing higher resolution observations to replace the current parametrised input. Observations by EISCAT_3D will also be used to monitor the direct effects from the Sun on the ionosphere-atmosphere system and those caused by solar wind magnetosphere-ionosphere interaction. In addition, EISCAT_3D will be used for remote sensing the large-scale behaviour of the magnetosphere from its
13. Thermal expansion of monogermanides of 3d-metals
Valkovskiy, G. A.; Altynbaev, E. V.; Kuchugura, M. D.; Yashina, E. G.; Sukhanov, A. S.; Dyadkin, V. A.; Tsvyashchenko, A. V.; Sidorov, V. A.; Fomicheva, L. N.; Bykova, E.; Ovsyannikov, S. V.; Chernyshov, D. Yu; Grigoriev, S. V.
2016-09-01
Temperature dependent powder and single-crystal synchrotron diffraction, specific heat, magnetic susceptibility and small-angle neutron scattering experiments have revealed an anomalous response of MnGe. The anomaly becomes smeared out with decreasing Mn content in Mn1‑x Co x Ge and Mn1‑x Fe x Ge solid solutions. Mn spin state instability is discussed as a possible candidate for the observed effects.
14. Thermal expansion of monogermanides of 3d-metals.
PubMed
Valkovskiy, G A; Altynbaev, E V; Kuchugura, M D; Yashina, E G; Sukhanov, A S; Dyadkin, V A; Tsvyashchenko, A V; Sidorov, V A; Fomicheva, L N; Bykova, E; Ovsyannikov, S V; Chernyshov, D Yu; Grigoriev, S V
2016-09-21
Temperature dependent powder and single-crystal synchrotron diffraction, specific heat, magnetic susceptibility and small-angle neutron scattering experiments have revealed an anomalous response of MnGe. The anomaly becomes smeared out with decreasing Mn content in Mn1-x Co x Ge and Mn1-x Fe x Ge solid solutions. Mn spin state instability is discussed as a possible candidate for the observed effects. PMID:27421076
15. Scoops3D: software to analyze 3D slope stability throughout a digital landscape
USGS Publications Warehouse
Reid, Mark E.; Christian, Sarah B.; Brien, Dianne L.; Henderson, Scott T.
2015-01-01
The computer program, Scoops3D, evaluates slope stability throughout a digital landscape represented by a digital elevation model (DEM). The program uses a three-dimensional (3D) method of columns approach to assess the stability of many (typically millions) potential landslides within a user-defined size range. For each potential landslide (or failure), Scoops3D assesses the stability of a rotational, spherical slip surface encompassing many DEM cells using a 3D version of either Bishop’s simplified method or the Ordinary (Fellenius) method of limit-equilibrium analysis. Scoops3D has several options for the user to systematically and efficiently search throughout an entire DEM, thereby incorporating the effects of complex surface topography. In a thorough search, each DEM cell is included in multiple potential failures, and Scoops3D records the lowest stability (factor of safety) for each DEM cell, as well as the size (volume or area) associated with each of these potential landslides. It also determines the least-stable potential failure for the entire DEM. The user has a variety of options for building a 3D domain, including layers or full 3D distributions of strength and pore-water pressures, simplistic earthquake loading, and unsaturated suction conditions. Results from Scoops3D can be readily incorporated into a geographic information system (GIS) or other visualization software. This manual includes information on the theoretical basis for the slope-stability analysis, requirements for constructing and searching a 3D domain, a detailed operational guide (including step-by-step instructions for using the graphical user interface [GUI] software, Scoops3D-i) and input/output file specifications, practical considerations for conducting an analysis, results of verification tests, and multiple examples illustrating the capabilities of Scoops3D. Easy-to-use software installation packages are available for the Windows or Macintosh operating systems; these packages
16. Effect of viewing distance on 3D fatigue caused by viewing mobile 3D content
Mun, Sungchul; Lee, Dong-Su; Park, Min-Chul; Yano, Sumio
2013-05-01
With an advent of autostereoscopic display technique and increased needs for smart phones, there has been a significant growth in mobile TV markets. The rapid growth in technical, economical, and social aspects has encouraged 3D TV manufacturers to apply 3D rendering technology to mobile devices so that people have more opportunities to come into contact with many 3D content anytime and anywhere. Even if the mobile 3D technology leads to the current market growth, there is an important thing to consider for consistent development and growth in the display market. To put it briefly, human factors linked to mobile 3D viewing should be taken into consideration before developing mobile 3D technology. Many studies have investigated whether mobile 3D viewing causes undesirable biomedical effects such as motion sickness and visual fatigue, but few have examined main factors adversely affecting human health. Viewing distance is considered one of the main factors to establish optimized viewing environments from a viewer's point of view. Thus, in an effort to determine human-friendly viewing environments, this study aims to investigate the effect of viewing distance on human visual system when exposing to mobile 3D environments. Recording and analyzing brainwaves before and after watching mobile 3D content, we explore how viewing distance affects viewing experience from physiological and psychological perspectives. Results obtained in this study are expected to provide viewing guidelines for viewers, help ensure viewers against undesirable 3D effects, and lead to make gradual progress towards a human-friendly mobile 3D viewing.
Shepherd, Orr; LePage, Andrew J.; Wijntjes, Geert J.; Zehnpfennig, Theodore F.; Sackos, John T.; Nellums, Robert O.
1999-01-01
Visidyne, Inc., teaming with Sandia National Laboratories, has developed the preliminary design for an innovative scannerless 3-D laser radar capable of acquiring, tracking, and determining the coordinates of small caliber projectiles in flight with sufficient precision, so their origin can be established by back projecting their tracks to their source. The design takes advantage of the relatively large effective cross-section of a bullet at optical wavelengths. Kay to its implementation is the use of efficient, high- power laser diode arrays for illuminators and an imaging laser receiver using a unique CCD imager design, that acquires the information to establish x, y (angle-angle) and range coordinates for each bullet at very high frame rates. The detection process achieves a high degree of discrimination by using the optical signature of the bullet, solar background mitigation, and track detection. Field measurements and computer simulations have been used to provide the basis for a preliminary design of a robust bullet tracker, the Counter Sniper 3-D Laser Radar. Experimental data showing 3-D test imagery acquired by a lidar with architecture similar to that of the proposed Counter Sniper 3-D Lidar are presented. A proposed Phase II development would yield an innovative, compact, and highly efficient bullet-tracking laser radar. Such a device would meet the needs of not only the military, but also federal, state, and local law enforcement organizations.
18. How to See Shadows in 3D
ERIC Educational Resources Information Center
Parikesit, Gea O. F.
2014-01-01
Shadows can be found easily everywhere around us, so that we rarely find it interesting to reflect on how they work. In order to raise curiosity among students on the optics of shadows, we can display the shadows in 3D, particularly using a stereoscopic set-up. In this paper we describe the optics of stereoscopic shadows using simple schematic…
19. Spatial Visualization by Realistic 3D Views
ERIC Educational Resources Information Center
Yue, Jianping
2008-01-01
In this study, the popular Purdue Spatial Visualization Test-Visualization by Rotations (PSVT-R) in isometric drawings was recreated with CAD software that allows 3D solid modeling and rendering to provide more realistic pictorial views. Both the original and the modified PSVT-R tests were given to students and their scores on the two tests were…
20. Virtual Representations in 3D Learning Environments
ERIC Educational Resources Information Center
Shonfeld, Miri; Kritz, Miki
2013-01-01
This research explores the extent to which virtual worlds can serve as online collaborative learning environments for students by increasing social presence and engagement. 3D environments enable learning, which simulates face-to-face encounters while retaining the advantages of online learning. Students in Education departments created avatars…
1. 3D Cell Culture in Alginate Hydrogels
PubMed Central
Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael
2015-01-01
This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue. PMID:27600217
2. GPM 3D Flyby of Hurricane Lester
NASA Video Gallery
This 3-D flyby of Lester was created using GPM's Radar data. NASA/JAXA's GPM core observatory satellite flew over Hurricane Lester on August 29, 2016 at 7:21 p.m. EDT. Rain was measured by GPM's ra...
3. Invertible authentication for 3D meshes
Dittmann, Jana; Benedens, Oliver
2003-06-01
Digital watermarking has become an accepted technology for enabling multimedia protection schemes. Based on the introduced media independent protocol schemes for invertible data authentication in references 2, 4 and 5 we discuss the design of a new 3D invertible labeling technique to ensure and require high data integrity. We combine digital signature schemes and digital watermarking to provide a public verifiable integrity. Furthermore the protocol steps in the other papers to ensure that the original data can only be reproduced with a secret key is adopted for 3D meshes. The goal is to show how the existing protocol can be used for 3D meshes to provide solutions for authentication watermarking. In our design concept and evaluation we see that due to the nature of 3D meshes the invertible function are different from the image and audio concepts to achieve invertibility to guaranty reversibility of the original. Therefore we introduce a concept for distortion free invertibility and a concept for adjustable minimum distortion invertibility.
4. Metrological characterization of 3D imaging devices
Guidi, G.
2013-04-01
Manufacturers often express the performance of a 3D imaging device in various non-uniform ways for the lack of internationally recognized standard requirements for metrological parameters able to identify the capability of capturing a real scene. For this reason several national and international organizations in the last ten years have been developing protocols for verifying such performance. Ranging from VDI/VDE 2634, published by the Association of German Engineers and oriented to the world of mechanical 3D measurements (triangulation-based devices), to the ASTM technical committee E57, working also on laser systems based on direct range detection (TOF, Phase Shift, FM-CW, flash LADAR), this paper shows the state of the art about the characterization of active range devices, with special emphasis on measurement uncertainty, accuracy and resolution. Most of these protocols are based on special objects whose shape and size are certified with a known level of accuracy. By capturing the 3D shape of such objects with a range device, a comparison between the measured points and the theoretical shape they should represent is possible. The actual deviations can be directly analyzed or some derived parameters can be obtained (e.g. angles between planes, distances between barycenters of spheres rigidly connected, frequency domain parameters, etc.). This paper shows theoretical aspects and experimental results of some novel characterization methods applied to different categories of active 3D imaging devices based on both principles of triangulation and direct range detection.
5. [3D virtual endoscopy of heart].
PubMed
Du, Aan; Yang, Xin; Xue, Haihong; Yao, Liping; Sun, Kun
2012-10-01
In this paper, we present a virtual endoscopy (VE) for diagnosis of heart diseases, which is proved efficient and affordable, easy to popularize for viewing the interior of the heart. The dual source CT (DSCT) data were used as primary data in our system. The 3D structure of virtual heart was reconstructed with 3D texture mapping technology based on graphics processing unit (GPU), and could be displayed dynamically in real time. When we displayed it in real time, we could not only observe the inside of the chambers of heart but also examine from the new angle of view by the 3D data which were already clipped according to doctor's desire. In the pattern of observation, we used both mutual interactive mode and auto mode. In the auto mode, we used Dijkstra Algorithm which treated the 3D Euler distance as weighting factor to find out the view path quickly, and, used view path to calculate the four chamber plane. PMID:23198444
6. 3D Virtual Reality for Teaching Astronomy
Speck, Angela; Ruzhitskaya, L.; Laffey, J.; Ding, N.
2012-01-01
We are developing 3D virtual learning environments (VLEs) as learning materials for an undergraduate astronomy course, in which will utilize advances both in technologies available and in our understanding of the social nature of learning. These learning materials will be used to test whether such VLEs can indeed augment science learning so that it is more engaging, active, visual and effective. Our project focuses on the challenges and requirements of introductory college astronomy classes. Here we present our virtual world of the Jupiter system and how we plan to implement it to allow students to learn course material - physical laws and concepts in astronomy - while engaging them into exploration of the Jupiter's system, encouraging their imagination, curiosity, and motivation. The VLE can allow students to work individually or collaboratively. The 3D world also provides an opportunity for research in astronomy education to investigate impact of social interaction, gaming features, and use of manipulatives offered by a learning tool on students’ motivation and learning outcomes. Use of this VLE is also a valuable source for exploration of how the learners’ spatial awareness can be enhanced by working in 3D environment. We will present the Jupiter-system environment along with a preliminary study of the efficacy and usability of our Jupiter 3D VLE.
7. 3D Cell Culture in Alginate Hydrogels
PubMed Central
Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael
2015-01-01
This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell–matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.
8. Collaborative annotation of 3D crystallographic models.
PubMed
Hunter, J; Henderson, M; Khan, I
2007-01-01
This paper describes the AnnoCryst system-a tool that was designed to enable authenticated collaborators to share online discussions about 3D crystallographic structures through the asynchronous attachment, storage, and retrieval of annotations. Annotations are personal comments, interpretations, questions, assessments, or references that can be attached to files, data, digital objects, or Web pages. The AnnoCryst system enables annotations to be attached to 3D crystallographic models retrieved from either private local repositories (e.g., Fedora) or public online databases (e.g., Protein Data Bank or Inorganic Crystal Structure Database) via a Web browser. The system uses the Jmol plugin for viewing and manipulating the 3D crystal structures but extends Jmol by providing an additional interface through which annotations can be created, attached, stored, searched, browsed, and retrieved. The annotations are stored on a standardized Web annotation server (Annotea), which has been extended to support 3D macromolecular structures. Finally, the system is embedded within a security framework that is capable of authenticating users and restricting access only to trusted colleagues.
9. A Rotation Invariant in 3-D Reaching
ERIC Educational Resources Information Center
Mitra, Suvobrata; Turvey, M. T.
2004-01-01
In 3 experiments, the authors investigated changes in hand orientation during a 3-D reaching task that imposed specific position and orientation requirements on the hand's initial and final postures. Instantaneous hand orientation was described using 3-element rotation vectors representing current orientation as a rotation from a fixed reference…
10. Spacecraft 3D Augmented Reality Mobile App
NASA Technical Reports Server (NTRS)
Hussey, Kevin J.; Doronila, Paul R.; Kumanchik, Brian E.; Chan, Evan G.; Ellison, Douglas J.; Boeck, Andrea; Moore, Justin M.
2013-01-01
The Spacecraft 3D application allows users to learn about and interact with iconic NASA missions in a new and immersive way using common mobile devices. Using Augmented Reality (AR) techniques to project 3D renditions of the mission spacecraft into real-world surroundings, users can interact with and learn about Curiosity, GRAIL, Cassini, and Voyager. Additional updates on future missions, animations, and information will be ongoing. Using a printed AR Target and camera on a mobile device, users can get up close with these robotic explorers, see how some move, and learn about these engineering feats, which are used to expand knowledge and understanding about space. The software receives input from the mobile device's camera to recognize the presence of an AR marker in the camera's field of view. It then displays a 3D rendition of the selected spacecraft in the user's physical surroundings, on the mobile device's screen, while it tracks the device's movement in relation to the physical position of the spacecraft's 3D image on the AR marker.
11. The New Realm of 3-D Vision
NASA Technical Reports Server (NTRS)
2002-01-01
Dimension Technologies Inc., developed a line of 2-D/3-D Liquid Crystal Display (LCD) screens, including a 15-inch model priced at consumer levels. DTI's family of flat panel LCD displays, called the Virtual Window(TM), provide real-time 3-D images without the use of glasses, head trackers, helmets, or other viewing aids. Most of the company initial 3-D display research was funded through NASA's Small Business Innovation Research (SBIR) program. The images on DTI's displays appear to leap off the screen and hang in space. The display accepts input from computers or stereo video sources, and can be switched from 3-D to full-resolution 2-D viewing with the push of a button. The Virtual Window displays have applications in data visualization, medicine, architecture, business, real estate, entertainment, and other research, design, military, and consumer applications. Displays are currently used for computer games, protein analysis, and surgical imaging. The technology greatly benefits the medical field, as surgical simulators are helping to increase the skills of surgical residents. Virtual Window(TM) is a trademark of Dimension Technologies Inc.
12. NASA Sees Typhoon Rammasun in 3-D
NASA Video Gallery
NASA's TRMM satellite flew over on July 14, 2014 at 1819 UTC and data was used to make this 3-D flyby showing thunderstorms to heights of almost 17km (10.5 miles). Rain was measured falling at a ra...
13. 3-D Teaching Models for All
ERIC Educational Resources Information Center
2010-01-01
Allowing a student to "see" through touch what other students see through a microscope can be a challenging task. Therefore, author Joan Bradley created three-dimensional (3-D) models with one student's visual impairment in mind. They are meant to benefit all students and can be used to teach common high school biology topics, including the…
14. Introduction to 3D Graphics through Excel
ERIC Educational Resources Information Center
Benacka, Jan
2013-01-01
The article presents a method of explaining the principles of 3D graphics through making a revolvable and sizable orthographic parallel projection of cuboid in Excel. No programming is used. The method was tried in fourteen 90 minute lessons with 181 participants, which were Informatics teachers, undergraduates of Applied Informatics and gymnasium…
15. 3D Cell Culture in Alginate Hydrogels.
PubMed
Andersen, Therese; Auk-Emblem, Pia; Dornish, Michael
2015-03-24
This review compiles information regarding the use of alginate, and in particular alginate hydrogels, in culturing cells in 3D. Knowledge of alginate chemical structure and functionality are shown to be important parameters in design of alginate-based matrices for cell culture. Gel elasticity as well as hydrogel stability can be impacted by the type of alginate used, its concentration, the choice of gelation technique (ionic or covalent), and divalent cation chosen as the gel inducing ion. The use of peptide-coupled alginate can control cell-matrix interactions. Gelation of alginate with concomitant immobilization of cells can take various forms. Droplets or beads have been utilized since the 1980s for immobilizing cells. Newer matrices such as macroporous scaffolds are now entering the 3D cell culture product market. Finally, delayed gelling, injectable, alginate systems show utility in the translation of in vitro cell culture to in vivo tissue engineering applications. Alginate has a history and a future in 3D cell culture. Historically, cells were encapsulated in alginate droplets cross-linked with calcium for the development of artificial organs. Now, several commercial products based on alginate are being used as 3D cell culture systems that also demonstrate the possibility of replacing or regenerating tissue.
16. 3D Printed Programmable Release Capsules.
PubMed
Gupta, Maneesh K; Meng, Fanben; Johnson, Blake N; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C
2015-08-12
17. Parallel CARLOS-3D code development
SciTech Connect
Putnam, J.M.; Kotulski, J.D.
1996-02-01
CARLOS-3D is a three-dimensional scattering code which was developed under the sponsorship of the Electromagnetic Code Consortium, and is currently used by over 80 aerospace companies and government agencies. The code has been extensively validated and runs on both serial workstations and parallel super computers such as the Intel Paragon. CARLOS-3D is a three-dimensional surface integral equation scattering code based on a Galerkin method of moments formulation employing Rao- Wilton-Glisson roof-top basis for triangular faceted surfaces. Fully arbitrary 3D geometries composed of multiple conducting and homogeneous bulk dielectric materials can be modeled. This presentation describes some of the extensions to the CARLOS-3D code, and how the operator structure of the code facilitated these improvements. Body of revolution (BOR) and two-dimensional geometries were incorporated by simply including new input routines, and the appropriate Galerkin matrix operator routines. Some additional modifications were required in the combined field integral equation matrix generation routine due to the symmetric nature of the BOR and 2D operators. Quadrilateral patched surfaces with linear roof-top basis functions were also implemented in the same manner. Quadrilateral facets and triangular facets can be used in combination to more efficiently model geometries with both large smooth surfaces and surfaces with fine detail such as gaps and cracks. Since the parallel implementation in CARLOS-3D is at high level, these changes were independent of the computer platform being used. This approach minimizes code maintenance, while providing capabilities with little additional effort. Results are presented showing the performance and accuracy of the code for some large scattering problems. Comparisons between triangular faceted and quadrilateral faceted geometry representations will be shown for some complex scatterers.
18. 3-D Force-balanced Magnetospheric Configurations
SciTech Connect
Sorin Zaharia; C.Z. Cheng; K. Maezawa
2003-02-10
The knowledge of plasma pressure is essential for many physics applications in the magnetosphere, such as computing magnetospheric currents and deriving magnetosphere-ionosphere coupling. A thorough knowledge of the 3-D pressure distribution has however eluded the community, as most in-situ pressure observations are either in the ionosphere or the equatorial region of the magnetosphere. With the assumption of pressure isotropy there have been attempts to obtain the pressure at different locations by either (a) mapping observed data (e.g., in the ionosphere) along the field lines of an empirical magnetospheric field model or (b) computing a pressure profile in the equatorial plane (in 2-D) or along the Sun-Earth axis (in 1-D) that is in force balance with the magnetic stresses of an empirical model. However, the pressure distributions obtained through these methods are not in force balance with the empirical magnetic field at all locations. In order to find a global 3-D plasma pressure distribution in force balance with the magnetospheric magnetic field, we have developed the MAG-3D code, that solves the 3-D force balance equation J x B = (upside-down delta) P computationally. Our calculation is performed in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials as B = (upside-down delta) psi x (upside-down delta) alpha. The pressure distribution, P = P(psi,alpha), is prescribed in the equatorial plane and is based on satellite measurements. In addition, computational boundary conditions for y surfaces are imposed using empirical field models. Our results provide 3-D distributions of magnetic field and plasma pressure as well as parallel and transverse currents for both quiet-time and disturbed magnetospheric conditions.
19. 3D microscopy for microfabrication quality control
Muller, Matthew S.; De Jean, Paul D.
2015-03-01
A novel stereo microscope adapter, the SweptVue, has been developed to rapidly perform quantitative 3D microscopy for cost-effective microfabrication quality control. The SweptVue adapter uses the left and right stereo channels of an Olympus SZX7 stereo microscope for sample illumination and detection, respectively. By adjusting the temporal synchronization between the illumination lines projected from a Texas Instruments DLP LightCrafter and the rolling shutter on a Point Grey Flea3 CMOS camera, micrometer-scale depth features can be easily and rapidly measured at up to 5 μm resolution on a variety of microfabricated samples. In this study, the build performance of an industrial-grade Stratasys Object 300 Connex 3D printer was examined. Ten identical parts were 3D printed with a lateral and depth resolution of 42 μm and 30 μm, respectively, using both a rigid and flexible Stratasys PolyJet material. Surface elevation precision and accuracy was examined over multiple regions of interest on plateau and hemispherical surfaces. In general, the dimensions of the examined features were reproducible across the parts built using both materials. However, significant systemic lateral and height build errors were discovered, such as: decreased heights when approaching the edges of plateaus, inaccurate height steps, and poor tolerances on channel width. For 3D printed parts to be used in functional applications requiring micro-scale tolerances, they need to conform to specification. Despite appearing identical, our 3D printed parts were found to have a variety of defects that the SweptVue adapter quickly revealed.
20. 3D Printed Programmable Release Capsules
PubMed Central
Gupta, Maneesh K.; Meng, Fanben; Johnson, Blake N.; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C.
2015-01-01
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https://kleinschmidt.wordpress.com/tag/fonts/
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## Posts Tagged ‘fonts’
### XeTeX: modern font support for TeX
If you know me at all you know that I love LaTeX. It let’s you specify the content and logical structure of your document and takes care of making it look nice, including tricky mathematical expressions, yadda yadda yadda.
One thing that LaTeX is really bad at, though, is font support. This isn’t a problem for the most part, and I’ve actually come to prefer the look of Computer Modern (the only real font ever created using Knuth’s Metafont language, and instantly recognizable to LaTeX geeks the world over). But if you need to, say, typeset something in Arial (shudder), there isn’t exactly an easy way to do it, and god forbid that you might want to use a font that’s not freely available (like, just an arbitrary example, Times New Roman).
Enter our hero, XeTeX (and it’s big sibling, XeLaTeX). XeLaTeX extends the low-level typesetting engine of TeX to use modern font/typography technology. This includes support for Unicode, and super-slick typography conventions like OpenType and Apple Advanced Typography (AAT), which allow the typesetting of scripts with complicated rules for combining symbols (like Tibetan) and different writing directions (e.g. right-to-left scripts such as Arabic and Hebrew).
The really great thing about XeTeX, for my current purposes, is that it allows you to typeset almost anything using any font installed natively on your computer. That is, XeTeX essentially adds that drop-down font-selection menu that every other text editor has.
As an example, I will show you how stupid-easy it is to typeset a document in 12 pt. Times New Roman (with 1-inch edges, not that it matters)
```\documentclass[12pt]{article} \usepackage[margin=1in]{geometry} \usepackage{fontspec} \setmainfont[Mapping=tex-text]{Times New Roman}```
Yes, folks, it really is that easy: just two lines of code (above and beyond the usual documentclass/geometry combo), and nothing whatsoever that needs to be converted using FontForge, etc. The only trick is that, instead of running latex, you run xelatex (which is easy to automate using emacs and AUCTeX).
As you can probably tell from the snippet above, the package you want to use is fontspec, which is the LaTeX interface for XeTeX’s font-specification system, and its documentation has lots of good examples.
• ## my name is dave
and this is my blog.
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http://www.ck12.org/algebra/Exponential-Growth/lesson/Exponential-Growth-BSC-ALG/
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<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
# Exponential Growth
## Functions with x as an exponent
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Exponential Growth
Suppose that 1000 people visited an online auction website during its first month in existence and that the total number of visitors to the auction site is tripling every month. Could you write a function to represent this situation? How many total visitors will the auction site have had after 9 months?
### Exponential Growth
Previously, we have seen the variable only used as the base in an exponential expression. In exponential functions, the exponent is the variable and the base is a constant.
The General Form of an Exponential Function is \begin{align*}y=a (b)^x\end{align*}, where \begin{align*}a=\end{align*} initial value and \begin{align*}b= growth \ factor\end{align*}.
In exponential growth situations, the growth factor must be greater than one.
\begin{align*}b>1\end{align*}
#### Let's use an exponential function to solve the following problem:
A colony of bacteria has a population of 3,000 at noon on Sunday. During the next week, the colony’s population doubles every day. What is the population of the bacteria colony at noon on Saturday?
Make a table of values and calculate the population each day.
Day 0 (Sun) 1 (Mon) 2 (Tues) 3 (Wed) 4 (Thurs) 5 (Fri) 6 (Sat)
Population (thousands) 3 6 12 24 48 96 192
To get the population of bacteria for the next day we multiply the current day’s population by 2 because it doubles every day. If we define \begin{align*}x\end{align*} as the number of days since Sunday at noon, then we can write the following: \begin{align*}P= 3 \cdot 2^x\end{align*}. This is a formula that we can use to calculate the population on any day. For instance, the population on Saturday at noon will be \begin{align*}P = 3 \cdot 2^6=3 \cdot 64 = 192\end{align*} thousand bacteria. We use \begin{align*}x=6\end{align*}, since Saturday at noon is six days after Sunday at noon.
#### Graphing Exponential Functions
Graphs of exponential growth functions show you how quickly the values of the functions get very large.
#### Let's use tables of values to complete the following problems:
1. Graph \begin{align*}y=2^x\end{align*}.
Make a table of values that includes both negative and positive values of \begin{align*}x\end{align*}. Substitute these values for \begin{align*}x\end{align*} to get the value for the \begin{align*}y\end{align*} variable.
\begin{align*}x\end{align*} \begin{align*}y\end{align*}
–3 \begin{align*}\frac{1}{8}\end{align*}
–2 \begin{align*}\frac{1}{4}\end{align*}
–1 \begin{align*}\frac{1}{2}\end{align*}
0 1
1 2
2 4
3 8
Plot the points on the coordinate axes to get the graph below. Exponential functions always have this basic shape: They start very small and then once they start growing, they grow faster and faster, and soon they become huge.
1. In the last problem, we produced a graph for \begin{align*}y=2^x\end{align*}. Compare that graph with the graph of \begin{align*}y = 3 \cdot 2^x\end{align*}.
\begin{align*}x\end{align*} \begin{align*}y\end{align*}
–2 \begin{align*}3 \cdot 2^{-2} = 3 \cdot \frac{1}{2^2} =\frac{3}{4}\end{align*}
–1 \begin{align*}3 \cdot 2^{-1} = 3 \cdot \frac{1}{2^1} = \frac{3}{2}\end{align*}
0 \begin{align*}3 \cdot 2^0 = 3\end{align*}
1 \begin{align*}3 \cdot 2^1 = 6\end{align*}
2 \begin{align*}3 \cdot 2^2 = 3 \cdot 4 = 12\end{align*}
3 \begin{align*}3 \cdot 2^3 = 3 \cdot 8 = 24\end{align*}
We can see that the function \begin{align*}y=3 \cdot 2^x\end{align*} is bigger than the function \begin{align*}y=2^x\end{align*}. In both functions, the value of \begin{align*}y\end{align*} doubles every time \begin{align*}x\end{align*} increases by one. However, \begin{align*}y=3 \cdot 2^x\end{align*} starts with a value of 3, while \begin{align*}y=2^x\end{align*} starts with a value of 1, so it makes sense that \begin{align*}y=3 \cdot 2^x\end{align*} would be bigger.
The shape of the exponential graph changes if the constants change. The curve can become steeper or shallower.
### Examples
#### Example 1
Earlier, you were told that 1000 people visited an online auction website during its first month in existence and that the total number of visitors to the auction site is tripling every month. What function represents this situation? How many total visitors will the auction site have had after 9 months?
To write the function, it is helpful to write out a table of values where \begin{align*}x\end{align*} is the month since the website opened and \begin{align*}y\end{align*} is the number of visitors
\begin{align*}x\end{align*} \begin{align*}y\end{align*}
1 1000
2 3000
3 9000
4 27000
5 81000
6 243000
7 729000
8 2187000
9 6561000
Notice that the initial value is 1000 and the growth factor is 3. Therefore, you would expect the exponential function that represents this situation to be:
\begin{align*}y = 1000 \cdot 3^x\end{align*}
However, if you plug in 1 to this equation, you will get 3000 instead of 1000. The exponent value is 1 above what it should be. Therefore, you need to decrease the exponent by 1 and the exponential function that represents this situation is:
\begin{align*}y = 1000 \cdot 3^{x-1}\end{align*}
If you plug in 1 to this equation, you will get 1000 as necessary. You should test the other numbers from the table in this equation to verify that the function is correct.
To find how many total visitors that the website would have had after 9 months, add all the values of \begin{align*}y\end{align*} in the table from above:
\begin{align*}1000 + 3000 + 9000 + 27000 + 81000 + 243000 + 729000 + 2187000 + 6561000 = 9841000\end{align*}In the first 9 months, the website had 9,841,000 total visitors.
#### Example 2
A population of 500 E. Coli organisms doubles every fifteen minutes. Write a function expressing the population size as a function of hours.
Since there are four 15 minute periods in an hour, this means the population will double 4 times in an hour. Doubling twice is the same thing as quadrupling since:
\begin{align*}1\cdot 2 \cdot 2=1\cdot 2^2=1 \cdot 4=4.\end{align*}
This means that doubling 4 times can be calculated as \begin{align*}2^4=16\end{align*}. So the population is 16 times as big every hour. With an initial population size of 500, the function is:
\begin{align*}f(x)=500\cdot 8^x\end{align*}
where \begin{align*}x\end{align*} is in hours and \begin{align*}f(x)\end{align*} is the number of organisms after \begin{align*}x\end{align*} hours.
### Review
1. What is the general form for an exponential equation? What do the variables represent?
2. How is an exponential growth equation different from a linear equation?
3. What is true about the growth factor of an exponential equation?
4. True or false? An exponential growth function has the following form: \begin{align*}f(x)=a(b)^x\end{align*}, where \begin{align*}a>1\end{align*} and \begin{align*}b<1\end{align*}?
5. What is the \begin{align*}y-\end{align*}intercept of all exponential growth functions?
Graph the following exponential functions by making a table of values.
1. \begin{align*}y=3^x\end{align*}
2. \begin{align*}y=2^x\end{align*}
3. \begin{align*}y=5 \cdot 3^x\end{align*}
4. \begin{align*}y=\frac{1}{2} \cdot 4^x\end{align*}
5. \begin{align*}f(x)=\frac{1}{3} \cdot 7^x\end{align*}
6. \begin{align*}f(x)=2 \cdot 3^x\end{align*}
7. \begin{align*}y=40 \cdot 4^x\end{align*}
8. \begin{align*}y=3 \cdot 10^x\end{align*}
Solve the following problems involving exponential growth.
1. A chain letter is sent out to 10 people telling everyone to make 10 copies of the letter and send each one to a new person. Assume that everyone who receives the letter sends it to 10 new people and that it takes a week for each cycle. How many people receive the letter in the sixth week?
2. Nadia received \$200 for her \begin{align*}10^{th}\end{align*} birthday. If she saves it in a bank with a 7.5% interest rate compounded yearly, how much money will she have in the bank by her \begin{align*}21^{st}\end{align*} birthday?
Mixed Review
1. Suppose a letter is randomly chosen from the alphabet. What is the probability the letter chosen is \begin{align*}M, K\end{align*}, or \begin{align*}L\end{align*}?
2. Evaluate \begin{align*}t^4 \cdot t^\frac{1}{2}\end{align*} when \begin{align*}t=9\end{align*}.
3. Simplify \begin{align*}28-(x-16)\end{align*}.
4. Graph \begin{align*}y-1=\frac{1}{3} (x+6)\end{align*}.
To see the Review answers, open this PDF file and look for section 8.7.
### Notes/Highlights Having trouble? Report an issue.
Color Highlighted Text Notes
### Vocabulary Language: English Spanish
TermDefinition
Exponential growth Exponential growth occurs when a quantity increases by the same proportion in each given time period.
general form of an exponential function $y=a (b)^x$, where $a=$ initial value and $b= growth \ factor$
Asymptotes An asymptote is a line on the graph of a function representing a value toward which the function may approach, but does not reach (with certain exceptions).
Model A model is a mathematical expression or function used to describe a physical item or situation.
|
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|
http://tex.stackexchange.com/questions/16443/guitar-tablatures-typesetting/111752
|
# Guitar tablatures typesetting?
So I kindof wanted to leave old and ugly ascii-art tabs and produce something nice, but found there's probably no method to typeset actual guitar tabs in TeX.
All I found was:
• MusiXTeX for classical music notation
• songbook for lyrics+chords above
• guitar.sty for something similar.
Is there something that does tabs and I missed it?
edit: I need TeX text around, it's for a (kind of) guitar textbook.
-
Do you mean something like this? openguitar.com/files/juba-short.pdf – Harold Cavendish Apr 23 '11 at 9:23
yeah, would be nice. With LaTeX text around, ofcourse :] – Mirek Kratochvil Apr 23 '11 at 12:13
Take a look at the hyperlink posted by Jefromi in the comment to my answer below. I was not aware of the possibility to integrate LilyPond with LaTeX. I think that this solution is what you are looking for. – Harold Cavendish Apr 23 '11 at 15:03
I think MusiXTeX has extensions for guitar tablature and guitar chord diagrams. – gniourf_gniourf Apr 23 '11 at 22:18
Are you searching for something like this? http://www.texample.net/tikz/examples/guitar-chords/
-
Not exactly what I wanted, but seems that a little latex macro work can easily tune it to the state I need. Thanks very much! – Mirek Kratochvil Apr 25 '11 at 10:00
My recommendation is to use LilyPond, which I believe was formerly based on TeX. It is possibly the best solution you can get for free. The file in my comment to your question is said to be typeset in it. Here is another possible output with displayed chords.
-
LilyPond seems like an excellent choice to me as well. There are also some very nice editors for it. – ipavlic Apr 23 '11 at 11:18
I believe LilyPond can be used along with LaTeX: lilypond.org/doc/v2.12/Documentation/user/lilypond-program/… – Jefromi Apr 23 '11 at 14:47
@Jefromi I have some experience with LilyPond, but I did not know this. Very useful for myself as well, thank you! – Harold Cavendish Apr 23 '11 at 15:04
In case anybody stumbles onto this question (like I just did):
I remembered having tried something like a tabulature with musixtex a little while ago. It is only a start and far from being perfect but shows that tabulatures can be done with a little effort.
\documentclass{article}
\usepackage{musixtex,graphicx}
% custom clef
\newcommand\TAB[1]{%
\setclefsymbol{#1}{\,\rotatebox{90}{TAB}}%
\setclef{#1}9}
% internal string choosing command
% #1: string (a number from 1--6)
% #2: finger
\makeatletter
\newcommand\@str[2]{%
\ifcase#1\relax\@strerror
\or\def\@strnr{-1}%
\or\def\@strnr{1}%
\or\def\@strnr{3}%
\or\def\@strnr{5}%
\or\def\@strnr{7}%
\or\def\@strnr{9}%
\else\@strerror
\fi
\zchar\@strnr{\footnotesize#2}}
% \@strerror could be defined to issue some warning/error
% User level commands
\newcommand\STr[2]{\@str{#1}{#2}\sk} % with a full note skip
\newcommand\Str[2]{\@str{#1}{#2}\hsk} % with a half note skip
\newcommand\str[2]{\@str{#1}{#2}} % with no skip
\makeatother
\begin{document}
\setlength\parindent{0pt}
\begin{music}
\instrumentnumber{1}
\nobarnumbers
\TAB1
\setlines1{6}
\startpiece
\Notes\hsk\STr37\en
\Notes\Str45\en
\Notes\Str55\en
\Notes\Str65\en
\bar
\Notes\str67\Str36\en
\Notes\Str45\en
\Notes\Str55\en
\Notes\Str67\en
\bar
\Notes\str68\Str35\en
\Notes\Str45\en
\Notes\Str55\en
\Notes\Str68\en
\bar
\Notes\Str34\en
\Notes\Str42\en
\Notes\Str53\en
\Notes\Str62\en
\bar
\Notes\Str33\en
\Notes\Str42\en
\Notes\Str51\en
\Notes\itieu0r\Str60\en
\bar
\Notes\ttie0\Str60\en
\Notes\Str51\en
\Notes\Str42\en
\Notes\Str33\en
\bar
\Notes\Str13\en
\Notes\Str20\en
\Notes\STr20\en
\bar
\Notes\STr20\en
\Notes\Str28\en
\Notes\STr27\en
\endpiece
\end{music}
\end{document}
Any one able to spot the song? ;)
-
I recently wanted to recreate chord tablature sheets that my guitar teacher used to use in his lessons. They were basically a grid of small tables with 5 times 4 cells. These tables were then filled by hand with the chords I was supposed to remember. Creating these tables is a piece of cake but I wanted the possibility to add the chord schemes with LaTeX, adding position, fingers, barrés, specify the root etc. with an easy syntax. I also wanted a similarly easy syntax for creating tablatures of scales.
I did what I always do in these cases: I wrote me a little package, guitarchordschemes, (which I will upload to CTAN if you deem it useful) that allows to do that. Below are a few examples:
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{guitarchordschemes}
\begin{document}
\chordscheme[
name = Gmi\textsuperscript{7($\flat$5)} ,
position = IX ,
finger = {3/4, 2/3, 3/2} ,
root = {2/5} ,
mute = {1,6}
]
\end{document}
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{guitarchordschemes}
\begin{document}
\chordscheme[
name = Gmi\textsuperscript{7($\flat$5)} ,
position = IX ,
finger = {3/4:3, 2/3:2, 3/2:4} ,
root = {2/5:1} ,
show-root = {4/3} ,
mute = {1,6}
]
\end{document}
\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{guitarchordschemes}
\begin{document}
\scales[
name = D major/position II ,
position = I ,
fingering = type 3
]
\end{document}
-
Have you tried with programs like GuitarPro 5? I'm sure you can export the tabs to pdf there...
-
Yeah, the problem is that it's not really good for actual typesetting, especially if you're writing a textbook. – Mirek Kratochvil Apr 23 '11 at 12:12
Open source Tuxguitar which is similar to GuitarPro can export your work to lilypond format. – ipavlic Apr 23 '11 at 15:59
Tuxguitar export to lilypond seems pretty good, gonna consider it. Thanks. – Mirek Kratochvil Apr 25 '11 at 9:58
|
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|
https://link.springer.com/article/10.1140%2Fepjc%2Fs10052-017-5184-z
|
The European Physical Journal C
, 77:626
# Measurement of meson resonance production in $$\pi ^-+$$ C interactions at SPS energies
The NA61/SHINE Collaboration
• Y. Ali
• E. V. Andronov
• T. Antićić
• B. Baatar
• M. Baszczyk
• S. Bhosale
• A. Blondel
• M. Bogomilov
• A. Brandin
• A. Bravar
• J. Brzychczyk
• S. A. Bunyatov
• O. Busygina
• H. Cherif
• M. Ćirković
• T. Czopowicz
• A. Damyanova
• N. Davis
• H. Dembinski
• M. Deveaux
• W. Dominik
• P. Dorosz
• J. Dumarchez
• R. Engel
• A. Ereditato
• S. Faas
• G. A. Feofilov
• Z. Fodor
• C. Francois
• X. Garrido
• A. Garibov
• M. Gaździcki
• M. Golubeva
• K. Grebieszkow
• F. Guber
• A. Haesler
• A. E. Hervé
• J. Hylen
• S. N. Igolkin
• A. Ivashkin
• S. R. Johnson
• E. Kaptur
• M. Kiełbowicz
• V. A. Kireyeu
• V. Klochkov
• V. I. Kolesnikov
• D. Kolev
• A. Korzenev
• V. N. Kovalenko
• K. Kowalik
• S. Kowalski
• M. Koziel
• A. Krasnoperov
• W. Kucewicz
• M. Kuich
• A. Kurepin
• D. Larsen
• A. László
• T. V. Lazareva
• M. Lewicki
• B. Lundberg
• B. Łysakowski
• V. V. Lyubushkin
• I. C. Mariş
• M. Maćkowiak-Pawłowska
• B. Maksiak
• A. I. Malakhov
• D. Manić
• A. Marchionni
• A. Marcinek
• A. D. Marino
• K. Marton
• H. -J. Mathes
• T. Matulewicz
• V. Matveev
• G. L. Melkumov
• A. O. Merzlaya
• B. Messerly
• Ł. Mik
• G. B. Mills
• S. Morozov
• S. Mrówczyński
• Y. Nagai
• V. Ozvenchuk
• V. Paolone
• M. Pavin
• O. Petukhov
• C. Pistillo
• R. Płaneta
• B. A. Popov
• S. Puławski
• J. Puzović
• R. Rameika
• W. Rauch
• M. Ravonel
• R. Renfordt
• E. Richter-Wąs
• D. Röhrich
• E. Rondio
• M. Roth
• B. T. Rumberger
• M. Ruprecht
• A. Rustamov
• M. Rybczynski
• A. Rybicki
• K. Schmidt
• I. Selyuzhenkov
• A. Yu. Seryakov
• P. Seyboth
• M. Słodkowski
• A. Snoch
• P. Staszel
• G. Stefanek
• J. Stepaniak
• M. Strikhanov
• H. Ströbele
• T. Šuša
• M. Szuba
• A. Taranenko
• A. Tefelska
• D. Tefelski
• V. Tereshchenko
• A. Toia
• R. Tsenov
• L. Turko
• R. Ulrich
• M. Unger
• F. F. Valiev
• D. Veberič
• V. V. Vechernin
• M. Walewski
• A. Wickremasinghe
• C. Wilkinson
• Z. Włodarczyk
• A. Wojtaszek-Szwarc
• O. Wyszyński
• L. Zambelli
• E. D. Zimmerman
Open Access
Regular Article - Experimental Physics
## Abstract
We present measurements of $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ spectra in $$\pi ^{-} +$$ C production interactions at 158 $$\text{ GeV }{/}\text{ c }$$ and $$\rho ^0$$ spectra at 350 $$\text{ GeV }{/}\text{ c }$$ using the NA61/SHINE spectrometer at the CERN SPS. Spectra are presented as a function of the Feynman’s variable $$x_\text {F}$$ in the range $$0< x_\text {F} < 1$$ and $$0< x_\text {F} < 0.5$$ for 158 and 350 $$\text{ GeV }{/}\text{ c }$$ respectively. Furthermore, we show comparisons with previous measurements and predictions of several hadronic interaction models. These measurements are essential for a better understanding of hadronic shower development and for improving the modeling of cosmic ray air showers.
## 1 Introduction
When cosmic rays of high energy collide with the nuclei of the atmosphere, they initiate extensive air showers (EAS). Earth’s atmosphere then acts as a medium in which the particle shower evolves. It proceeds mainly through the production and interaction of secondary pions and kaons. Depending on the particle energy and density of the medium in which the shower evolves, secondary particles either decay or re-interact, producing further secondaries. Neutral pions have a special role. Instead of interacting hadronically, they immediately decay ($$c\bar{\tau }= 25$$ nm) into two photons with a branching ratio of 99.9%, giving rise to an electromagnetic shower component. When only the primary particle energy is of interest, and all shower components are sampled, a detailed understanding of the energy transfer from the hadronic particles to the electromagnetic shower component is not needed. However, for other measurements of air shower properties this understanding is of central importance.
A complete measurement of an air shower is not possible and particles are typically sampled only in select positions at the ground level or the ionization energy deposited in the atmosphere is measured. Therefore, the interpretation of EAS data, and in particular the determination of the composition of cosmic rays, relies to a large extent on a correct modelling of hadron-air interactions that occur during the shower development (see e.g. [1]). Experiments such as the Pierre Auger Observatory [2], IceTop [3], KASCADE-Grande [4] or the Telescope Array [5] use models for the interpretation of measurements. However, there is mounting evidence that current hadronic interaction models do not provide a satisfactory description of the muon production in air showers and that there is a deficit in the number of muons predicted at the ground level by the models when compared to the air shower measurements (see Refs. [6, 7, 8, 9, 10]).
To understand the possible cause of this deficit it is instructive to study the air shower development in a very simplified model [11] in which mesons are produced in subsequent interactions of the air cascade until the average meson energy is low enough such that its decay length is smaller than its interaction length. In each interaction a fraction $$f_\mathrm {em}$$ of the shower energy is transferred to the electromagnetic shower component via the production and decay of neutral mesons. After n interactions the energy available in the hadronic part of the shower to produce muons is therefore $$E_\mathrm {had} = E_0 \, (1-f_\mathrm {em})^n$$, where $$E_0$$ denotes the primary energy of the cosmic ray initiating the air shower. In the standard simplified picture, one third of the interactions products of charged pions with air are neutral mesons. Assuming a typical value of $$n=7$$ for the number of interactions needed to reach particle energies low enough that the charged mesons decay to muons rather than interact again, the simplistic model gives $$E_\mathrm {had} / E_0 \simeq 6\%$$. One way to increase this number is to account for the production of baryons and antibaryons to decrease $$f_\mathrm {em}$$ [12]. Another possibilty has been recently identified [13, 14] by noting that accelerator data on $$\pi ^+ + \text {p}$$ interactions [15, 16, 17] indicate that most of the neutral mesons produced in the forward direction are not $$\pi ^0$$s but $$\rho ^0$$ mesons. With $$\rho ^0$$ decaying into $$\pi ^+\,\pi ^-$$ this would imply that the energy of the leading particle is not transferred to the electromagnetic shower component as it would be in the case of neutral pions and corresponingly $$f_\mathrm {em}$$ is decreased leading to more muons at ground level.
Given these considerations it is evident that the modeling of air showers depends crucially on our knowledge of pion interactions with air. It can be shown (see e.g. [18, 19]) that the relevant energies for the interactions in the last stage of the air shower development are in the range from 10 to $$10^3$$ $$\text{ GeV }$$. This range is accessible to fixed-target experiments with charged pion beams.
A large body of data is available at these energies for proton-nucleus interactions (e.g. [20, 21, 22, 23, 24]), but only a very limited amount of data exists for pion or kaon beams. A number of dedicated measurements for air-shower simulations have been performed by studying particle production on light nuclei at beam momenta up to 12 $$\text{ GeV }{/}\text{ c }$$ (see, e.g. Refs. [25, 26]). Unfortunately, at higher energies, there are no comprehensive and precise particle production measurements of $$\pi$$ interactions with light nuclei of masses similar to air. Earlier measurements were either limited to a small acceptance in momentum space (e.g. Ref. [27]) or protons as target [15, 16, 17, 28], or did not discriminate between the different secondaries [29].
To address the lack of suitable data for the tuning of hadronic interaction models used in air shower simulations, NA61/SHINE [30] collected new data with negatively charged pion beams at 158 and 350 $$\text{ GeV }{/}\text{ c }$$ on a thin carbon target. Preliminary spectra of unidentified hadrons and identified pions were previously derived from this data set [31, 32, 33] and in this paper, we present the results of the measurement of $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ spectra in $$\pi ^{-}$$ + C interactions at 158 and 350 $$\text{ GeV }{/}\text{ c }$$.
It is worthwhile noting that the measurements presented in this paper will not only be useful for interpretation of cosmic-ray calorimetry in air, but can also be beneficial for the understanding of hadronic calorimeters used in high-energy laboratory experiments. Hadronic interaction models used for calorimeter simulations are mostly tuned to and validated with the overall calorimeter response from test-beam data (see e.g. [34, 35, 36]). A tuning of these models to the data presented here will improve the description of the energy transfer from the hadronic to the electromagnetic shower component for individual interactions inside the calorimeter and thus increase the predictive power of the calorimeter simulation.
The paper is organized as follows: A brief description of the experimental setup, the collected data, data reconstruction and simulation is presented in Sect. 2. The analysis technique used to measure meson resonance production in $$\pi$$ + C interactions is described in Sect. 3. The final results, with comparison to model predictions, and other experimental data are presented in Sect. 4. A summary in Sect. 5 closes the paper.
## 2 Experimental setup, data processing and simulation
The NA61/SHINE apparatus is a wide-acceptance hadron spectrometer at the CERN SPS on the H2 beam line of the CERN North Area. A detailed description of the experiment is presented in Ref. [30]. Only features relevant for the $$\pi ^-$$ + C data are briefly mentioned here. Numerous components of the NA61/SHINE setup were inherited from its predecessor, the NA49 experiment [37]. An overview of the setup used for data taking on $$\pi ^-$$ + C interactions in 2009 is shown in Fig. 1.
The detector is built around five time projection chambers (TPCs), as shown in Fig. 1b. Two Vertex TPCs (VTPC-1 and VTPC-2) are placed in the magnetic field produced by two superconducting dipole magnets and two Main-TPCs (MTPC-L and MTPC-R) are located downstream symmetrically with respect to the beamline. An additional small TPC is placed between VTPC-1 and VTPC-2, covering the very-forward region, and is referred to as the GAP TPC (GTPC).
The magnet current setting for data taking at 158 and 350 $$\text{ GeV }{/}\text{ c }$$ corresponds to 1.5 T in the first and 1.1 T, in the second magnet. It results in a precise measurement of the particle momenta p with a resolution of $$\sigma (p)/p^2\approx (0.3{-}7)\times 10^{-4}\,\mathrm {(GeV/c)}^{-1}$$.
Two scintillation counters, S1 and S2, together with the three veto counters V0, V1 and V1$$^\text {p}$$, define the beam upstream of the target. The setup of these counters can be seen in Fig. 1a for the 158 $$\text{ GeV }{/}\text{ c }$$ run. The S1 counter also provides the start time for all timing measurements.
The 158 and 350 $$\text{ GeV }{/}\text{ c }$$ secondary hadron beam was produced by 400 $$\text{ GeV }{/}\text{ c }$$ primary protons impinging on a 10 cm long beryllium target. Negatively charged hadrons ($$\text {h}^-$$) produced at the target are transported downstream to the NA61/SHINE experiment by the H2 beamline, in which collimation and momentum selection occur. The beam particles, mostly $$\pi ^-$$ mesons, are identified by a differential ring-imaging Cherenkov detector CEDAR [38]. The fraction of pions is $${\approx }95\%$$ for 158 $$\text{ GeV }{/}\text{ c }$$ and $${\approx }100\%$$ for 350 $$\text{ GeV }{/}\text{ c }$$ (see Fig. 2). The CEDAR signal is recorded during data taking and then used as an offline selection cut (see Sect. 3.1). The beam particles are selected by the beam trigger, T$$_\text {beam}$$, then defined by the coincidence $$\text {S1}\wedge \text {S2}\wedge \overline{\text {V0}} \wedge \overline{\text {V1}}\wedge \overline{\text {V1}^\text {p}}$$. The interaction trigger ($$\text {T}_\text {int} = \text {T}_\text {beam} \wedge \overline{\text {S4}}$$) is given by the anti-coincidence of the incoming beam particle and S4, a scintillation counter, with a diameter of 2 cm, placed between the VTPC-1 and VTPC-2 detectors along the beam trajectory at about 3.7 m from the target, see Fig. 1a, b. Almost all beam particles that interact inelastically in the target do not reach S4. The interaction and beam triggers were recorded in parallel. The beam trigger events were recorded with a frequency by a factor of about 10 lower than the frequency of interaction trigger events.
The incoming beam trajectory is measured by a set of three beam position detectors (BPDs), placed along the beamline upstream of the target, as shown in Fig. 1a. These detectors are $$4.8 \times 4.8$$ cm$$^2$$ proportional chambers. Each BPD measures the position of the beam particle on the transverse plane with respect to the beam direction with a resolution of $${\sim }100\,\upmu$$m (see Ref. [30] for more details).
For data taking on $$\pi ^-$$ + C interactions, the target was an isotropic graphite plate with a thickness along the beam axis of 2 cm with a density of $$\rho =1.84$$ g/cm$$^3$$, equivalent to about 4% of a nuclear interaction length. During the data taking the target was placed 80 cm upstream of VTPC-1. 90% of data was recorded with the target inserted and 10% with the removed target. The latter set was used to estimate the bias due to interactions with the material upstream and downstream of the target.
Detector parameters were optimised using a data-based calibration procedure which also took into account their time dependences. Minor adjustments were determined in consecutive steps for:
1. (i)
detector geometry and TPC drift velocities and
2. (ii)
magnetic field map.
Each step involved reconstruction of the data required to optimise a given set of calibration constants and time dependent corrections followed by verification procedures. Details of the procedure and quality assessment are presented in Ref. [39].
The main steps of the data reconstruction procedure are:
1. (i)
finding of clusters in the TPC raw data, calculation of the cluster centre-of-gravity and total charge,
2. (ii)
reconstruction of local track segments in each TPC separately,
3. (iii)
matching of track segments into global tracks,
4. (iv)
fitting of the track through the magnetic field and determination of track parameters at the first measured TPC cluster,
5. (v)
determination of the interaction vertex using the beam trajectory fitted in the BPDs and the trajectories of tracks reconstructed in the TPCs (the final data analysis uses the middle of the target as the z-position, $$z=-580\,$$cm) and
6. (vi)
refitting of the particle trajectory using the interaction vertex as an additional point and determining the particle momentum at the interaction vertex.
An example of a reconstructed $$\pi ^-$$ + C interaction at 158 $$\text{ GeV }{/}\text{ c }$$ is shown in Fig. 3. Amongst the many tracks visible are five long tracks of three negatively charged and two positively charged particles, with momentum ranging $$5{-}50$$ $$\text{ GeV }{/}\text{ c }$$.
A simulation of the NA61/SHINE detector response is used to correct the measured raw yields of resonances. For the purposes of this analysis, the Epos 1.99 model was used for the simulation and calculation of correction factors. DPMJet 3.06 [40] was used as a comparison for estimation of systematic uncertainties. The choice of Epos was made due to both the number of resonances included in the model, as well as the ability to include the intrinsic width of these resonances in the simulation. Epos 1.99 rather than Epos LHC was used as it is better tuned to the measurements at SPS energies [41].
The simulation consists of the following steps:
1. (i)
generation of inelastic $$\pi ^-$$ + C interactions using the Epos 1.99 model,
2. (ii)
propagation of outgoing particles through the detector material using the Geant 3.21 package [42] which takes into account the magnetic field as well as relevant physics processes, such as particle interactions and decays,
3. (iii)
simulation of the detector response using dedicated NA61/SHINE packages which also introduce distortions corresponding to all corrections applied to the real data,
4. (iv)
simulation of the interaction trigger selection by checking whether a charged particle hits the S4 counter,
5. (v)
storage of the simulated events in a file which has the same format as the raw data,
6. (vi)
reconstruction of the simulated events with the same reconstruction chain as used for the real data and
7. (vii)
matching of the reconstructed to the simulated tracks based on the cluster positions.
For more details on the reconstruction and calibration algorithms applied to the raw data, as well as the simulation of the NA61/SHINE detector response, used to correct the raw data, see Ref. [43].
## 3 Analysis
In this section we present the analysis technique developed for the measurement of the $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ spectra in $$\pi ^-$$ + C production interactions. Production interactions are interactions with at least one new particle produced, i.e. interactions where only elastic or quasi-elastic scattering occurred are excluded. The procedure used for the data analysis consists of the following steps:
1. (i)
application of event and track selection criteria,
2. (ii)
combination of oppositely charged tracks,
3. (iii)
accumulating the combinations in bins of Feynman-x, $$x_\text {F}$$, calculated by using the mass of the $$\rho ^0$$ meson for the boost between the lab and centre of mass frames,
4. (iv)
calculation of the invariant mass of each combination, assuming pion masses for the particles,
5. (v)
fitting of the invariant mass distributions with templates of resonance decays to obtain raw yields and
6. (vi)
application of corrections to the raw yields calculated from simulations.
These steps are described in the following subsections.
### 3.1 Event and track selection
A total of $$5.49\times 10^6$$ events were recorded at 158 $$\text{ GeV }{/}\text{ c }$$ and $$4.48\times 10^6$$ events were recorded at 350 $$\text{ GeV }{/}\text{ c }$$. All events used in the analysis are required to pass cuts to ensure both an interaction event and events of good quality. These cuts are:
1. (i)
Well-contained measurements of the beam with the BPDs and a successful reconstruction of the beam direction.
2. (ii)
Pion identification with the CEDAR (only for 158 $$\text{ GeV }{/}\text{ c }$$ as the impurity of the 350 $$\text{ GeV }{/}\text{ c }$$ beam is below 0.1%).
3. (iii)
No extra (off-time) beam particles detected within $$\pm 2\,\upmu$$s of the triggered beam particle.
4. (iv)
All events must have an interaction trigger as defined in Sect. 2.
5. (v)
The main vertex point is properly reconstructed.
6. (vi)
The z-position of the interaction vertex must be between $$-597$$ and $$-563$$ cm.
The cut (vi) is illustrated in Fig. 4 and its purpose is to remove the majority of interactions that do not occur in the target. This cut will increase the Monte Carlo correction because some in-target events are removed due to the vertex-z resolution. The vertex-z resolution depends on the multiplicity of an event and is about 4.5 cm for low multiplicities and better than 0.5 cm for high multiplicites. The cut is choosen loose enough ($$\pm 17$$ cm around the target center) to assure both a high efficiency for all multiplicities and a purity of in-target of better than 99%.
An alternative method to correct for out-of-target interactions would be to measure the resonance yields in the target-removed data, but the template-fitting method used in this paper can not be applied to data sets with small statistics such as the target-removed data.
The range of this cut, ($$-597,-563$$) cm, was selected to maximise the event number, while minimising the contamination due to off-target events. The residual contribution of non-target interactions after applying this cut is 0.8%.
Table 1
Number of events after each event selection cut and selection efficiency with respect to the previous cut for the target inserted data set for 158 and 350 $$\text{ GeV }{/}\text{ c }$$ beam momentum
$$p_\text {beam}$$
$$158\,\text{ GeV }{/}\text{ c }$$
$$350\,\text{ GeV }{/}\text{ c }$$
Cut
$$N_\text {events}$$
Efficiency (%)
$$N_\text {events}$$
Efficiency (%)
Total
$$5.49\times 10^6$$
100
$$4.48\times 10^6$$
100
(i)
BPD
$$4.96\times 10^6$$
90.3
$$4.08\times 10^6$$
91.1
(ii)
CEDAR
$$4.26\times 10^6$$
85.9
$$4.08\times 10^6$$
100
(iii)
Off-time
$$4.03\times 10^6$$
94.5
$$3.94\times 10^6$$
96.5
(iv)
Trigger
$$3.34\times 10^6$$
83.0
$$2.97\times 10^6$$
75.3
(v)
Vertex fit
$$3.29\times 10^6$$
98.5
$$2.95\times 10^6$$
99.5
(vi)
z-position
$$2.78\times 10^6$$
84.6
$$2.59\times 10^6$$
87.9
Table 2
Number of tracks after each track selection cut and selection efficiency with respect to the previous cut for the target inserted data set for 350 $$\text{ GeV }{/}\text{ c }$$ beam momentum
$$p_\text {beam}$$
$$158\,\text{ GeV }{/}\text{ c }$$
$$350\,\text{ GeV }{/}\text{ c }$$
Cut
$$N_\text {tracks}$$
Efficiency (%)
$$N_\text {tracks}$$
Efficiency (%)
Total
$$3.85\times 10^7$$
100
$$4.41\times 10^7$$
100
(i)
Track quality
$$2.27\times 10^7$$
59.0
$$2.77\times 10^7$$
62.8
(ii)
Acceptance
$$1.57\times 10^7$$
69.0
$$1.99\times 10^7$$
72.0
(iii)
Total clusters
$$1.54 \times 10^7$$
98.1
$$1.95 \times 10^7$$
98.2
(iv)
TPC clusters
$$1.51 \times 10^7$$
98.0
$$1.91 \times 10^7$$
97.8
(v)
Impact parameters
$$1.42 \times 10^7$$
94.4
$$1.80 \times 10^7$$
94.1
The number of events after these cuts is $$2.78 \times 10^6$$ for 158 $$\text{ GeV }{/}\text{ c }$$ and $$2.59 \times 10^6$$ for 350 $$\text{ GeV }{/}\text{ c }$$. The efficiency of these cuts is shown in Table 1 for 158 and 350 $$\text{ GeV }{/}\text{ c }$$ beam momentum.
After the event cuts were applied, a further set of quality cuts were applied to the individual tracks. These were used to ensure a high reconstruction efficiency as well as reducing contamination by tracks from secondary interactions. These cuts are:
1. (i)
The track is well reconstructed at the interaction vertex.
2. (ii)
The fitted track is inside the geometrical acceptance of the detector.
3. (iii)
The total number of clusters on the track should be greater than or equal to 30.
4. (iv)
The sum of clusters on the track in VTPC-1 and VTPC-2 should be greater than or equal to 15, or the total number of clusters on the track in GTPC should be greater than or equal to 6.
5. (v)
The distance of closest approach of the fitted track to the interaction point (impact parameter) is required to be less than 2 cm in the x-plane and 0.4 cm in the y-plane.
For the acceptance cut, (ii), we studied the selection efficiency with simulations as a function of azimuthal angle $$\phi$$ for bins in total momentum p and transverse momentum $$p_\text {T}$$. This leads to a three-dimensional lookup table that defines the regions in $$(\phi , p, p_\text {T})$$ for which the selection efficiency is larger than 90%. Within this region, the detector is close to fully efficient and the corresponding correction factor is purely geometric, since the production of resonances is uniform in $$\phi$$ for an unpolarised beam and target.
The efficiency of each track-selection cut is shown in Table 2 for the data collected at 158 and 350 $$\text{ GeV }{/}\text{ c }$$.
No particle identification was used in this analysis. This increases the background but simplifies the analysis and increases the longitudinal momentum range of the results. The longitudinal momentum fraction, $$x'_\text {F}$$, was calculated as
\begin{aligned} x'_\text {F} = \frac{2p_\text {L}}{\sqrt{s}} \quad \left( \approx \frac{p_\text {L}}{p_\text {L}(\mathrm {max})}\right) , \end{aligned}
(1)
where $$p_\text {L}$$ is the longitudinal momentum of the $$\rho ^0$$-candidate in the centre of mass frame in the pion-nucleon interaction and $$\sqrt{s}$$ is the centre of mass energy of the interaction. $$p_\text {L}$$ is calculated using the mean mass of the $$\rho ^0$$ meson ($$m_{\rho ^0} = 0.775\,\text{ GeV }{/}\text{ c }^2$$) when boosting between the lab frame and the centre of mass frame. The mass of the nucleon used in the calculations is taken to be the average of the proton and neutron masses. There is no difference between $$x'_\text {F}$$ and the Feynman-x, $$x_\text {F} =p_\text {L}/p_\text {L} (\text {max})$$, for a particle pair originating from a $$\rho ^0$$ meson decay. For $$\omega$$ or K$$^{*0}$$ decays the difference is less than 0.01 in the $$x'_\text {F}$$ range covered by the results presented here. This difference approaches zero with increasing $$x'_\text {F}$$. For simplicity, in the following, $$x'_\text {F}$$ is denoted as $$x_\text {F}$$.
### 3.2 Signal extraction
The raw yields of $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ mesons were obtained by performing a fit of inclusive invariant mass spectra. These were calculated by assuming every track that passes the cuts is a charged $$\pi$$. Then, for all pairs of positively and negatively charged particles, the invariant mass was calculated assuming pion masses for both particles. Examples of invariant mass spectra at 158 and 350 $$\text{ GeV }{/}\text{ c }$$ are shown in Fig. 5.
In the inclusive invariant mass spectra, there is a large combinatorial background, especially at low $$x_\text {F}$$. The method used to estimate the background is the so-called charge mixing method, which uses the invariant mass spectra calculated exactly as explained above, but using same-charge instead of opposite-charge tracks. The resulting charge mixing background spectra are shown in Fig. 5. As the normalisation of these spectra will differ from the true background, the normalisation of the charge-mixed spectra is included as a parameter in the fit to the data. The uncertainty introduced by choosing this method of calculating the background is estimated by comparing it with a background found from simulations. This Monte Carlo background is defined as the sum of:
• combinations of tracks that come from decays of different resonances, i.e. one track from a $$\rho ^0$$ and one from an $$\omega$$ (this can be done as the parent particles of tracks are known in the simulation),
• combinations of tracks coming directly from the interaction vertex and
• combinations of tracks coming from resonances (both meson and baryon) that are not included in the individual fitting-templates listed below.
As can be seen in Fig. 5, there is a good overall agreement between the two background estimation methods and the residual differences are used to estimate the systematics due to background subtraction. The boundaries of the default fit range are chosen to include all resonances of interest and to select the invariant mass region for which there is good agreement between the two background estimates, and hence the results have small systematic biases. This leads to the fit range in $$m_\text {inv} (\pi ^+\pi ^-)$$ of $$0.475{-}1.35\,\text{ GeV }{/}\text{ c }^2$$.
Event mixing was also investigated as an alternative way to estimate the background by taking particles from different events to make invariant mass spectra of $$\pi ^+\pi ^-$$ candidates, but this method was found to not describe the shape of the background in simulations over the mass range of the $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ distributions needed to obtain reliable fit results. Refining the event mixing method by splitting the data into multiplicity classes did not improve the quality of this method.
As there is a large number of resonances in the $$m_\text {inv} (\pi ^+\pi ^-)$$ region around the mass of the $$\rho ^0$$, such as the $$\omega$$ and K$$^{*0}$$ mesons, they all have to be taken into account. This has previously been shown in Ref. [44], where only taking into account $$\rho ^0$$ and $$\omega$$ mesons resulted in an inadequate fit, with a spurious peak at 0.6 $$\text{ GeV }{/}\text{ c }^2$$ in the $$\pi ^+\pi ^-$$ invariant mass spectra, due to decays of K$$^{*0}$$ mesons, where the kaon is assigned the mass of a pion. As there is no particle identification used in this analysis, the effect due to K$$^{*0}$$ meson production is expected to be strong and it must be included in the fitting procedure. Other contributions that are not represented by an individual template, such as $$\Lambda$$ decay products, are included in the Monte Carlo background.
The fitting procedure uses templates of the invariant mass distribution for each resonance of importance. This method of template fitting is similar to ideas used by many other experiments such as ALICE [45], ATLAS [46], CDF [47] and CMS [48], where it is also known as the cocktail fit method. The use of independent templates without interference terms is a good approximation, because the mass differences between resonances decaying to $$\pi ^+ + \pi ^-$$ are either large as compared to their width or they decay to $$\pi ^+ + \pi ^-$$ with small branching ratio only (e.g. about 1.5% for $$\omega$$).
The templates are constructed by passing simulated $$\pi ^-$$ + C production interactions, generated with the Epos 1.99 [12] hadronic interaction model using Crmc 1.5.3 [49], through the full NA61/SHINE detector Monte Carlo chain and then through the same reconstruction routines as the data. Crmc is an event generator package with access to a variety of different event generators, such as DPMJet 3.06 [40] and Epos LHC [50].
The template method also allows for the fitting of resonances with dominant three body decays, such as $$\omega$$, as well as resonances with two-body non-$$\pi ^+\pi ^-$$ decays, such as K$$^{*0}$$. A list of all decays with a branching ratio of over $$1\%$$ that are used in the templates is shown in Table 3. The templates and the data are split into bins of $$x_\text {F}$$, calculated as in Eq. 1.
Table 3
Decays of resonances for which $$m_\text {inv} (\pi ^+\pi ^-)$$ templates were calculated and fitted. Only decays with a branching ratio greater than 1% into at least one positively and one negatively charged particle are considered. Branching ratios were taken from [51]
Resonance
Decay
Branching ratio
$$\rho ^0$$
$$\pi ^+\pi ^-$$
100.0
$$\omega$$
$$\pi ^+\pi ^-\pi ^0$$
89.1
$$\pi ^+\pi ^-$$
1.53
K$$^{*0}$$
$$\pi$$
100.0
f$$_2$$
$$\pi ^+\pi ^-$$
57.0
$$\pi ^+\pi ^-\,2\pi ^0$$
7.7
K$$^+$$K$$^-$$
4.6
$$2\pi ^+\,2\pi ^-$$
2.8
$$\eta$$
$$\pi ^+\pi ^-\pi ^0$$
22.7
$$\pi ^+\pi ^-\gamma$$
4.6
f$$_0$$ (980)
$$\pi ^+\pi ^-$$
50.0
K$$^+$$K$$^-$$
12.5
a$$_2$$
$$3\pi$$
70.1
$$\eta \,\pi$$
14.5
$$\omega \,\pi \,\pi$$
10.6
$$\bar{\text {K}}$$
4.9
$$\rho _3$$
$$4\pi$$
71.1
$$\pi \,\pi$$
23.6
K K $$\pi$$
3.8
$$\bar{\text {K}}$$
1.58
K$$^0_\text {S}$$
$$\pi ^+\pi ^-$$
69.20
The templates in the fit are the charge mixing background and the following resonances: $$\rho ^0$$, K$$^{*0}$$, $$\omega$$, f$$_2$$, f$$_0$$ (980), a$$_2$$, $$\rho _3$$, $$\eta$$ and K$$^0_\text {S}$$. The templates were generated from reconstructed simulations that have all the standard reconstruction cuts applied; they include effects due to the resolution of the detector and the fiducial acceptance. The templates used in the fits are presented in Fig. 15 in Appendix B. As can be seen, the a$$_2$$ and $$\rho _3$$ templates are broad and featureless similar to the background template. For this reason, these resonances cannot be fitted reliably and will be subtracted together with the background from figures displaying the result of the template fitting in the following.
The fit to the $$\pi ^+\pi ^-$$ mass spectrum is performed between masses of 0.475 and 1.35 $$\text{ GeV }{/}\text{ c }^2$$ using the expression
\begin{aligned} \mu (m_\text {inv}) = \sum _i f_i \, T_i(m_\text {inv}), \end{aligned}
(2)
where $$f_i$$ is the contribution for particle i, $$T_i$$ is the associated invariant mass template and $$m_\text {inv}$$ is the invariant mass. $$f_i$$ is constrained to be between 0 and 1. The templates are normalised to the same number of combinations as the data over the range of the fit. The fit uses a standard Poissonian likelihood function
\begin{aligned} \mathcal {L} = \prod _j \frac{\mu _j^{k_j} e^{-\mu _j}}{k_j!}, \end{aligned}
(3)
where $$k_j$$ is the actual number of combinations in the invariant mass bin j and $$\mu _j$$ is the expected number of combinations, taken from Eq. (2).
Two examples of the template-fitting are shown in Fig. 6 for 158 and 350 $$\text{ GeV }{/}\text{ c }$$. The fitted charge-mixing background as well as the contribution of the featureless a$$_2$$ and $$\rho _3$$ resonances are subtracted to highlight the different resonances. The full set of template fits are displayed in Appendix C for all $$x_\text {F}$$-bins and the two beam energies.
After the fractions of each templates have been determined in the fit, the raw mean multiplicity $$n_i$$ of meson i per event in a given $$x_\text {F}$$ bin is determined from
\begin{aligned} n_i(x_\text {F}) = \frac{1}{N_\text {acc}} \sum _j f_i \, T_i(j), \end{aligned}
(4)
where $$N_\text {acc}$$ is the number of events after selection cuts, $$f_i$$ is the result of the fit and $$T_i$$ is the template of the meson of interest i, e.g. $$\rho ^0$$.
### 3.3 Correction factors
In order to obtain the true number of $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ mesons produced in $$\pi ^-$$ + C production interactions, three different corrections were applied to the raw yields. These corrections were calculated using 20 million events generated by the Epos 1.99 model using the Crmc package.
1. (i)
The Monte Carlo simulations that were used to obtain the templates for the fitting procedure were used to calculate corrections due to geometrical acceptance, reconstruction efficiency, losses due to trigger bias, quality cuts and bin migration effects. For each $$x_\text {F}$$ bin, the correction factor $$C(x_\text {F})$$ is given by
\begin{aligned} C(x_\text {F}) = \frac{n_\text {MC}^\text {gen}(x_\text {F})}{n_\text {MC}^\text {acc}(x_\text {F})}, \end{aligned}
(5)
where
1. (a)
$$n_\text {MC}^\text {gen}(x_\text {F})$$ is the mean multiplicity per event of $$\rho ^0$$ ($$\omega$$, K$$^{*0}$$) mesons produced in a given $$x_\text {F}$$ bin in $$\pi ^-$$ + C production interactions at a given beam momentum, including $$\rho ^0$$ ($$\omega$$, K$$^{*0}$$) mesons from higher mass resonance decays and
2. (b)
$$n_\text {MC}^\text {acc}(x_\text {F})$$ is the mean multiplicity per event of reconstructed $$\rho ^0$$ ($$\omega$$, K$$^{*0}$$) mesons that are accepted after applying all event and track cuts.
The statistical uncertainties of the corrections factors were calculated assuming binomial distributions for the number of events and resonances.
2. (ii)
The contribution from $$\rho ^0$$ mesons produced by re-interactions in the target. This was estimated from the simulations. This contribution is less than 1% for all bins apart from $$x_\text {F} <0.15$$, where the contribution is 1.7%.
3. (iii)
The fitting method was validated by applying the same procedure to the simulated data set, using the background estimated from either the charge mixing method or the true background obtained from the simulation. This difference is then applied as a multiplicative correction to the raw yield, $$f_i^\text {true} / f_i^\text {fit}$$, where $$f_i^\text {true}$$ is the true yield of resonance i and $$f_i^\text {fit}$$ is the yield that comes from the fit to the simulations. This correction is calculated separately for both background estimations and applied to the fits to the data that used the same estimation.
The breakdown of these correction factors can be seen, for the $$\rho ^0$$ spectra at $$p_\text {beam}=158$$ and $$350\,\text{ GeV }{/}\text{ c }$$, in Fig. 7. The correction factor $$C(x_\text {F})$$ is broken down into three contributions: bias from the interaction trigger (T2), geometrical acceptance, and selection efficiency. The geometrical acceptance dominates for large $$x_\text {F}$$ values.
The correction derived from Monte Carlo simulations could introduce a bias in the result if the $$p_\text {T}$$ spectrum of the model differed from the true shape. This is because the extrapolation to full $$p_\text {T}$$ phase space is based on the model spectrum. To investigate this effect another hadronic interaction model was used, DPMJet 3.06 [40]. This model also provides $$p_\text {T}$$ spectra for each resonance measured in this analysis, and the difference between the correction factors found for DPMJet 3.06 and Epos 1.99 is less than 4%. This suggests that any bias introduced by the extrapolation to full $$p_\text {T}$$ phase space is small. The difference between the correction factors is used in the estimate of the systematic uncertainties.
The final measurement is calculated by taking the average of the result using the two different background description methods, charge mixing and Monte Carlo background, with all the correction factors that change calculated separately for the two methods. The difference between these two methods is taken to be a systematic uncertainty.
### 3.4 Uncertainties and Cross Checks
The statistical uncertainties in the ith $$x_\text {F}$$-bin are given by
\begin{aligned} \sigma _i^2 = \left( \Delta C_i \, n_i\right) ^2 + \left( \frac{\sigma (n_i)}{C_i}\right) ^2, \end{aligned}
(6)
where $$n_i$$ and $$\sigma (n_i)$$ are the raw meson mean multiplicity per event and the uncertainty on this multiplicity that comes from the template fit. The contribution due to the uncertainty of the meson multiplicity dominates as the uncertainty $$\Delta C_i$$ of the corrections factors is only from the statistics of the simulation (20 million events) which is much larger than that of the data.
The main contributors to the systematic uncertainties are
1. (i)
The fitting method used for estimating the background shape and the fit procedure. The systematic uncertainty is taken to be half the difference between the two methods, using either charge mixing or Monte Carlo background, after the respective validation corrections have been applied. This estimate therefore combines the systematic uncertainty due to both the fitting method validation correction and the background estimation used and this is the dominant systematic uncertainty.
2. (ii)
Correction factors. The correction factors calculated above were compared with factors found using a different hadronic interaction model, DPMJet 3.06.
3. (iii)
Track cuts. The effect of the event and track selection cuts were checked by performing the analysis with the following cuts changed, compared to the values shown in Sect. 3.1.
1. (a)
The cut on the z-position of the interaction vertex was changed to be between $$-590$$ and $$-570$$ cm.
2. (b)
The window in which off-time beam particles were not allowed was decreased from 2 to 1.5 $$\upmu$$s.
3. (c)
The minimum number of clusters on the track was decreased to 25.
4. (d)
The sum of clusters on the track in VTPC-1 and VTPC-2 was decreased to 12 or increased to 18.
5. (e)
The impact parameter cuts were increased to less than 4 cm in the x-plane and 2 cm in the y-plane.
The systematic uncertainties were estimated from the differences between the results obtained using the standard analysis and ones obtained when adjusting the method as listed above. The individual systematic uncertainties were added in quadrature to obtain the total systematic uncertainties. They are dominated by the correction factor contribution, up to 15%, whereas the other contributions are less than 4%. Other sources of uncertainty, such as using templates from a different model, are found to be much smaller.
The fraction of target removed tracks is less than $$0.15\%$$ in all $$x_\text {F}$$ bins. The shape of the target removed distributions, after applying all the track and event cuts, is consistent with the background description so there is no additional correction or systematic uncertainty considered.
Several cross checks were performed to validate the results and check their stability. These include extending the range of the $$m_\text {inv} (\pi ^+\pi ^-)$$ fit, using the Breit–Wigner function to describe the $$\rho ^0$$ instead of a template as well as a few other more simple checks.
#### 3.4.1 Fit range
The default fit range used in this analysis was restricted to the mass ranges of the resonances of interest. We tested an extended fit range by including all data down to the kinematic threshold of $$m_\text {inv} (\pi ^+\pi ^-) = 2m_\pi$$. For this purpose additional templates needed to be taken into account including electrons and positrons pair-produced in the target by photons from $$\pi ^0$$ decays. The sum of all resonances produced by the Epos 1.99 model can however not describe the low $$m_\text {inv} (\pi ^+\pi ^-)$$ region satisfactorily. In particular, a significant bump at a mass of $${\approx }0.4\,\text{ GeV }{/}\text{ c }^2$$ appears to be in the data that does not have a counterpart in the templates. No resonance, meson or baryon, could be found in Epos 1.99 that could describe this bump. To avoid any bias the region of $$0.35\,\text{ GeV }{/}\text{ c }^2< m_\text {inv} (\pi ^+\pi ^-) < 0.4\,\text{ GeV }{/}\text{ c }^2$$ was excluded from the fit. Further discussions about the study of this bump are given in Appendix D.
Once this region is excluded from the fit a reasonable description of the $$m_\text {inv}$$ distribution down to the kinematic limit can be achieved, as shown in Fig. 8. However, the fit quality is worse and the agreement between the two background estimates is weaker. The poorer fit quality is most likely a combination of poorer performance of the estimate of the combinatorial background close to the kinematic threshold and the missing template to describe the bump at $${\approx }0.375\,\text{ GeV }{/}\text{ c }^2$$.
The yields obtained with the extended range differ by less than the systematic uncertainties from the yields with the original range, with the exception of one bin, and, to be conservative, the corresponding differences, which are of the order of 10%, are included in the systematic uncertainty.
#### 3.4.2 $$\rho ^0$$ mass
We checked for possible nuclear effects on the $$\rho ^0$$ mass [52, 53] by removing the $$\rho ^0$$ template from the fit and replacing it with a Breit–Wigner function. The function used is the one used in Ref. [54] with a modification to the decay width following Refs. [55] and [56], where the decay width is a function of mass $$m_\text {inv}$$,
\begin{aligned} {\text {BW}}(m_\text {inv}) = \frac{m_\text {inv} \, m_\text {R} \, \Gamma }{(m_\text {R}^2 - m_\text {inv} ^2)^2 + m_\text {R}^2 \, \Gamma ^2}, \end{aligned}
(7)
where $$m_\text {R}$$ is the mean mass of the fitted resonance and $$\Gamma$$ is given by
\begin{aligned} \Gamma (m_\text {inv}) = \Gamma _0 \left( \frac{m_\text {R}}{m_\text {inv}} \right) \left( \frac{q}{q_\text {R}} \right) ^{3/2} \left( \frac{q_\text {R}^2 + \delta ^2}{q^2 + \delta ^2} \right) , \end{aligned}
(8)
where q and $$q_\text {R}$$ are the pion three-momenta in the rest frame of the resonance, calculated with mass $$m_\text {inv}$$ and $$m_\text {R}$$, respectively. The parameter $$\delta$$ in the cutoff function has a value $$\delta = 0.3\,\text{ GeV }{/}\text{ c }$$.
We considered the mass as a free parameter and fixed the width value to the one provided by the particle data group [51]. The obtained mass values are consistent with the values quoted by the particle data group as shown in Fig. 9. The weighted average of the fitted masses is $$0.772\pm 0.001\,\text{ GeV }{/}\text{ c }^2$$, with no significant difference between the 158 and 350 $$\text{ GeV }{/}\text{ c }$$ data.
A simpler Breit–Wigner function was also tested,
\begin{aligned} {\text {BW}}(M) = \frac{\Gamma ^2}{(M - m_\text {R})^2 + \Gamma ^2} \end{aligned}
(9)
It is the function used to both sample resonances and generate their widths in Epos 1.99. Even though this function does not directly take into account effects which are considered in the event generator, such as decay products approaching the lower kinematic limit, or energy conservation for decay products at higher mass, the resulting fitted masses are compatible with the results from the more complicated Breit–Wigner function, Eq. (7).
The yields of the $$\rho ^0$$ when fitting with this Breit–Wigner function differ slightly from the yields calculated using the standard analysis method. These small differences of the order of 3% are included in the systematic uncertainties.
A comparison of the yields from the standard template analysis method, the extended fit range and when fitting a Breit–Wigner function (Eq. (7)) is shown in Fig. 10. As can be seen the differences are within the systematic uncertainties of the standard analysis. These small differences, of the order of 3% for the fits with a Breit–Wigner function and 10% for the extended fit range, are added in quadrature to the systematic uncertainties.
#### 3.4.3 Further checks
Further cross checks were performed to probe the stability of the fit and yield result. These include
1. (i)
The data, along with the templates, were split into two equally sized regions of polar angle. If there was any polar-angle dependence of the result introduced by insufficient modeling of different parts of the detector, this would appear in a difference between the spectra from these independent data sets. The resulting multiplicity spectra were consistent within statistical uncertainties.
2. (ii)
The data set was split according to different time ranges, both a night and day split as well as a first half and second half split in run taking. Any possible systematic differences in the detector which depend on time would result in discrepancies in the spectra from the different time ranges. Both resulting $$x_\text {F}$$ spectra were again consistent within statistical uncertainties.
3. (iii)
Instead of assuming the pion mass for both tracks, one track was allocated the kaon mass. This means that the number of combinations used has to double, as both combinations of masses have to be taken into account for any given pair of tracks to allow for the kaon to be either of the two charges. This also then increases the background even further and because of the different shape of the background under the $$\pi$$ K invariant mass distribution, the systematic uncertainty for this method is larger than for the $$\pi \,\pi$$ method. The multiplicity spectra from this method were consistent within statistical and systematic uncertainties of the standard analysis method.
All these performed cross checks gave results consistent within the total uncertainties of the standard analysis.
## 4 Results
The yields of $$\rho ^0$$, $$\omega$$, and K$$^{*0}$$ mesons in $$\pi ^{-}$$ + C production interactions at 158 and 350 $$\text{ GeV }{/}\text{ c }$$ were calculated in bins of $$x_\text {F}$$ as follows
\begin{aligned} \frac{\mathrm {d}n}{\mathrm {d}x_\text {F}} = \frac{1}{N_\text {prod}} \frac{\mathrm {d}N_\text {part}}{\mathrm {d}x_\text {F}} = \frac{C(x_\text {F}) \, n(x_\text {F})}{\Delta x_\text {F}}, \end{aligned}
(10)
where $$N_\text {prod}$$ is the number of interaction events minus the events with elastic and quasi-elastic scattering (which are not included), $$N_\text {part}$$ is the true number of produced resonances, $$n(x_\text {F})$$ is the raw mean multiplicity per event of the meson from Eq. (4), $$\Delta x_\text {F}$$ is the width of the $$x_\text {F}$$ bin and $$C(x_\text {F})$$ is the total correction factor for losses of event and multiplicity, as detailed above. Measured points with large statistical or systematic uncertainties (greater than 50%) are not shown. This cut removes three data points at large $$x_\text {F}$$ for the $$\omega$$ spectrum and one data point at large $$x_\text {F}$$ for the K$$^{*0}$$ spectrum at 158 $$\text{ GeV }{/}\text{ c }$$. In case of the data taken at $$350\,\text{ GeV }{/}\text{ c }$$ only a limited $$x_\text {F}$$-range between 0 and 0.5 is accessible within the acceptance of NA61/SHINE. Only one data point of the $$\omega$$ spectrum survived the cut on the maximum uncertainty and none for the K$$^{*0}$$ spectrum. Therefore we present only $$\rho ^0$$ spectra for the $$350\,\text{ GeV }{/}\text{ c }$$ data.
The spectra of $$\rho ^0$$, $$\omega$$, and K$$^{*0}$$ mesons produced in production $$\pi ^-$$ + C interactions are shown in Fig. 11. The average $$x_\text {F}$$ in each bin is used to display the data points in this and in the following figures. It is worthwhile noting that this average is not corrected for the detector acceptance within the bin and is calculated from all oppositely charge combinations including combinatorial background, i.e. for each $$x_\text {F}$$ bin i the average is given by the arithmetic mean $$\langle x_\text {F} \rangle _{i} = \frac{1}{N_i} \sum _{j=1}^{N_i} (x_\text {F})_j$$, where the sum runs over all $$N_i$$ track combinations in the bin. For a detailed comparison of this data with model predictions it is therefore recommended to compare to model predictions binned in the same way as the data rather than comparing them at the average $$x_\text {F}$$.
As can be seen in Fig. 11, no dependence of the $$\rho ^0$$ multiplicities on beam energy was found within the uncertainties of the measurement. Out of the three resonances studied here, the multiplicity of $$\rho ^0$$ mesons is the largest at large $$x_\text {F}$$, i.e. the region most relevant for the development of cosmic-ray air showers. Numerical results, including statistical and systematic uncertainties, are given in Tables 4, 5, and 6. It is worthwhile noting that due to improvements in the analysis procedure the final $$\rho ^0$$ multiplicities at 158 $$\text{ GeV }{/}\text{ c }$$ listed in Table 4 are about 25% smaller than the preliminary results presented in [33].
The measured spectra are compared to model predictions by QGSJet II-04 [58], Epos 1.99 [12], DPMJet 3.06 [40], Sibyll 2.1 [59], Sibyll 2.3 [60] and Epos LHC [50] in Figs. 12 and 13. For the purpose of display, the multiplicities were scaled by $$x_\text {F}$$.
It can be seen that in the low $$x_\text {F}$$ region ($$<0.3$$) all hadronic interaction models overestimate the $$\rho ^0$$ yield with discrepancies of up to +80%. At intermediate $$x_\text {F}$$ ($$0.4< x_\text {F} < 0.7$$) the $$\rho ^0$$ production is underestimated by up to $$-60$$%. It is interesting to note that even if QGSJet II-04, Sibyll 2.3 and Epos LHC were tuned to $$\pi ^+$$+p data from NA22 [17], these models cannot reproduce the measurement presented here. The large underestimation in QGSJet II-04 is mainly for non-forward $$\rho ^0$$ production which is not treated explicitly in the model. This explains the large difference in spectral shape compared to the other hadronic models and the large deviations between the model and the measurement. The best description of our data in the forward range ($$x_\text {F} >0.4$$) is given by Sibyll 2.3, which describes the data within 10%.
The shape of the measured $$\omega$$ spectrum is in approximate agreement with all of the models shown (QGSJet II-04 does not include $$\omega$$ mesons in the model). Also the measured normalisation is approximately reproduced by all models but Epos 1.99, which produces too many $$\omega$$ mesons above $$x_\text {F} >0.1$$.
The measured multiplicity of K$$^{*0}$$ mesons is not reproduced by any of the models over the full $$x_\text {F}$$ range. DPMJet 3.06 gives a correct description of the yields only at low $$x_\text {F}$$ but underpredicts the multiplicity at large $$x_\text {F}$$ and the opposite is true for Epos LHC and Epos 1.99 which are in agreement with the measurement only at $$x_\text {F} \gtrsim 0.6$$. Sibyll 2.3 and Sibyll 2.1 predict a too low number of K$$^{*0}$$ mesons at all $$x_\text {F}$$ values.
The ratio between combinations of the three meson measurements are shown in Fig. 21 in Appendix E, where it can be seen that no model can consistently describe the results.
The comparison between results from this analysis to measurements of other experiments are presented in Fig. 14 for $$\rho ^0$$ and $$\omega$$ mesons. The two other experiments shown are NA22 [17] and LEBC-EHS (NA27) [57], both of which used a hydrogen target. NA22 had a $$\pi ^+$$ beam at 250 $$\text{ GeV }{/}\text{ c }$$ while LEBC-EHS had a $$\pi ^-$$ beam at 360 $$\text{ GeV }{/}\text{ c }$$. The results from NA22 and LEBC-EHS are scaled by their measured inelastic cross sections: $$20.94\pm 0.12\,\text{ mb }$$ for NA22 [61] and $$21.6\,\text{ mb }$$ for LEBC-EHS [57]. There is good agreement between the previous measurements with proton targets and the results from this analysis for $$x_\text {F} <0.6$$. At larger $$x_\text {F}$$ the $$\rho ^0$$ yields measured in this analysis show a decrease that is not present in the $$\pi$$+p data and could thus be an effect of the nuclear target used for the measurement presented here. The comparison of the measurements of the $$\omega$$ multiplicities shows no significant differences between the other experiments and results from this analysis.
## 5 Summary
This article presents experimental results on $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ $$x_\text {F}$$-spectra in $$\pi ^-$$ + C production interactions at $$158\,\text{ GeV }{/}\text{ c }$$ and the $$\rho ^0$$ spectra at 350 $$\text{ GeV }{/}\text{ c }$$ from the NA61/SHINE spectrometer at the CERN SPS. These results are the first $$\pi ^-$$ + C measurements taken in this energy range and are important to tune hadronic interaction models used to understand the measurements of cosmic-ray air showers.
The comparisons of the measured spectra to predictions of hadronic interaction models suggests that for all models further tuning is required to reproduce the measured spectra of $$\rho ^0$$, $$\omega$$ and K$$^{*0}$$ mesons in the full range of $$x_\text {F}$$. Recent re-tunes of these models to resonance data in $$\pi +p$$ interactions resulted in changes of the muon number at ground of up to 25% [14, 60]. The new data provided here for $$\pi$$ + C interactions gives a more adequate reference for pion-air interactions relevant for air showers and will help to establish the effect of forward resonance production on muons in air showers with the precision needed for using the muon number to estimate the particle type of primary cosmic rays, as e.g. planned within the upgrade of the Pierre Auger Observatory [62].
## Notes
### Acknowledgements
We would like to thank the CERN EP, BE and EN Departments for the strong support of NA61/SHINE. This work was supported by the Hungarian Scientific Research Fund (Grants OTKA 68506 and 71989), the János Bolyai Research Scholarship of the Hungarian Academy of Sciences, the Polish Ministry of Science and Higher Education (Grants 667/N-CERN/2010/0, NN 202 48 4339 and NN 202 23 1837), the Polish National Center for Science (Grants 2011/03/N/ST2/03691, 2013/11/N/ST2/03879, 2014/13/N/ST2/02565, 2014/14/E/ST2/00018 and 2015/18/M/ST2/00125, 2015/19/N/ST2 /01689), the Foundation for Polish Science — MPD program, co-financed by the European Union within the European Regional Development Fund, the Federal Agency of Education of the Ministry of Education and Science of the Russian Federation (SPbSU research Grant 11.38.242.2015), the Russian Academy of Science and the Russian Foundation for Basic Research (Grants 08-02-00018, 09-02-00664 and 12-02-91503-CERN), the National Research Nuclear University MEPhI in the framework of the Russian Academic Excellence Project (contract No. 02.a03.21.0005, 27.08.2013), the Ministry of Education, Culture, Sports, Science and Technology, Japan, Grant-in-Aid for Scientific Research (Grants 18071005, 19034011, 19740162, 20740160 and 20039012), the German Research Foundation (Grant GA 1480/2-2), the EU-funded Marie Curie Outgoing Fellowship, Grant PIOF-GA-2013-624803, the Bulgarian Nuclear Regulatory Agency and the Joint Institute for Nuclear Research, Dubna (bilateral contract No. 4418-1-15/17), Bulgarian National Science Fund (Grant DN08/11), Ministry of Education and Science of the Republic of Serbia (Grant OI171002), Swiss Nationalfonds Foundation (Grant 200020117913/1), ETH Research Grant TH-01 07-3 and the US Department of Energy.
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## Authors and Affiliations
• 16
• Y. Ali
• 13
• E. V. Andronov
• 22
• T. Antićić
• 3
• B. Baatar
• 20
• M. Baszczyk
• 14
• S. Bhosale
• 11
• A. Blondel
• 25
• M. Bogomilov
• 2
• A. Brandin
• 21
• A. Bravar
• 25
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• 13
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• 20
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• 7
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• 23
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• 18
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• 25
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• 11
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• 5
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• 7
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• 16
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• 14
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• 4
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• 22
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• 7
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• 13
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• 4
• E. D. Zimmerman
• 28
• 26
1. 1.National Nuclear Research CenterBakuAzerbaijan
2. 2.Faculty of PhysicsUniversity of SofiaSofiaBulgaria
3. 3.Ruđer Bošković InstituteZagrebCroatia
4. 4.LPNHEUniversity of Paris VI and VIIParisFrance
5. 5.Karlsruhe Institute of TechnologyKarlsruheGermany
6. 6.Fachhochschule FrankfurtFrankfurtGermany
7. 7.University of FrankfurtFrankfurtGermany
8. 8.Wigner Research Centre for Physics of the Hungarian Academy of SciencesBudapestHungary
9. 9.University of BergenBergenNorway
10. 10.Jan Kochanowski University in KielceKielcePoland
11. 11.H. Niewodniczański Institute of Nuclear Physics of the Polish Academy of SciencesKrakówPoland
12. 12.National Centre for Nuclear ResearchWarsawPoland
13. 13.Jagiellonian UniversityKrakówPoland
14. 14.AGH University of Science and TechnologyKrakowPoland
15. 15.University of SilesiaKatowicePoland
16. 16.University of WarsawWarsawPoland
17. 17.University of WrocławWrocławPoland
18. 18.Warsaw University of TechnologyWarsawPoland
19. 19.Institute for Nuclear ResearchMoscowRussia
20. 20.Joint Institute for Nuclear ResearchDubnaRussia
21. 21.National Research Nuclear University (Moscow Engineering Physics Institute)MoscowRussia
22. 22.St. Petersburg State UniversitySt. PetersburgRussia
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http://www.math.uni-bonn.de/ag/ana/WiSe1415/S5B1_WS_14_15.html?language=en
|
Instructors
Prof. Dr. Herbert Koch, Prof. Dr. Christoph Thiele, Dr. Roland Donninger
Friday, 14 (c.t.) - 16, Seminar room 1.008
Talks
• October 17, 2014: Polona Durcik (University of Bonn)
Title: A proof of the A_2 theorem.
Abstract: We present an alternative proof of the A_2 theorem given by A. Lerner, F. Nazarov. Their approach is based on pointwise estimates of Calderon-Zygmund operators with dyadic sparse operators.
• October 24, 2014: Gennady Uraltsev (University of Bonn)
Title: Quadratic Carleson in the Walsh case.
Abstract: We will present V. Lie's proof of the weak L^2 boundedness of the quadratic Carleson operator revisited in the Walsh case. We hope that this approach clarifies the main ideas of the proof while simplifying some technical estimates. Finally, we will highlight the additional machinery needed to prove strong L^2 bounds directly.
• October 31, 2014: Shaoming Guo (University of Bonn)
Title: Geometric propf of Bourgain's L^2 bounds of the maximal operator along analytic vector fields.
Abstract: We will apply the time-frequency decomposition initiated by Lacey and Li to provide a geometric proof of Bourgain's L^2 bounds of the maximal operator along analytic vector fields.
• November 7, 2014: Michal Warchalski (University of Bonn)
Title: Wittwer's inequality via outer measure spaces.
Abstract: We will present a proof of a generalization of Wittwer's inequality with an arbitrary reference measure given by Christoph Thiele, Sergei Treil and Alexander Volberg. For this we will use embeddings into outer measure spaces and concavity arguments.
• November 14, 2014: Christian Zillinger (University of Bonn)
Title: Linear inviscid damping for monotone shear flows.
Abstract: We will present a proof of linear stability, scattering and damping for monotone shear flow solutions to the 2D Euler equations both in an infinite and finite periodic channel. A particular focus will be on the additional boundary effects arising in the latter setting.
• November 21, 2014:
The first speaker [2:15 pm]: Damiano Foschi (Universita di Ferrara)
Title: Local wellposedness of semilinear Schrodinger equations under minimal smoothness assumptions for the nonlinearity
Abstract:
The problem of local well-posedness for semilinear Schrodinger equations $i u_t + \Delta u = f(u)$ is well understood for smooth nonlinearities. When we consider power-like nonlinear terms of the form $f(u) = |u|^{p-1} u$ the degree of the power is also a measure of the smoothness (near zero) of the nonlinearity. A simple scaling argument can show that local wellposedness for the initial value problem with data in the Sobolev space $H^s$ requires that $p \leq 1 + 4/(n-2s)_+$. This scaling condition alone usually is not sufficient. Known results require also some lower bound for $p$: Cazenave and Weissler (1990) proved LWP with $p > \floor{s} + 1$; arguments of Ginibre, Ozawa and Velo (1994) allowed to relax the condition to $p > s$; Pecher (1997) improved to $p > s-1$ when $2 < s < 4$, and $p > s-2$ when $s \geq 4$; recently Uchizono and Wada (2012) obtained LWP with $p < s/2$ when $2 < s < 4$. We will show that these lower bounds for $p$ are not yet optimal. For example when $s=4$ we will show how to obtain LWP for $p > 3/2$.
The second speaker [3:15 pm]: Bartosz Trojan (University of Wroclaw)
Title: Bourgain's logarithmic lemma: 2-parameter case.
Abstract: We discuss 2-parameter generalization of Bourgain's logarithmic lemma arising in the context of pointwise ergodic theory.
• November 28, 2014: Mariana Smit Vega Garcia
Title: New developments in the lower dimensional obstacle problem
Abstract: We will describe the Signorini, or lower-dimensional obstacle problem, for a uniformly elliptic, divergence form operator $L =$ div$(A(x)\nabla)$ with Lipschitz continuous coefficients. We will give an overview of this problem and discuss some recent developments, including the optimal regularity of the solution and the regularity of the free boundary. This is joint work with Nicola Garofalo and Arshak Petrosyan.
• December 5, 2014: Pavel Zorin-Kranich (University of Bonn)
• Title: Variational Walsh Carleson
Abstract: I will motivate and present a version of Bourgain's multi-frequency lemma with two bounded r-variation hypotheses due to Oberlin.
• December 12, 2014: Wenhui Shi (University of Bonn)
Title: A higher order boundary Harnack inequality.
Abstract: We will present a higher order boundary Harnack inequality for harmonic functions and show its application to the free boundary problems. This is a method due to De Silva and Savin.
• January 16, 2015: Pawel Biernat (University of Bonn)
Title: Formal construction of singular solutions to harmonic map heat flow.
Abstract: Heat flow for harmonic maps is known to produce finite-time singularities from smooth initial data. These singular solutions arise for a large class of initial data and present a major obstacle in solving the heat flow equation for arbitrarily large times. I will show how to (formally) construct such singular solutions using matched asymptotics and how to determine their blow-up rate (the speed with which the singularity forms).
• January 23, 2015: Emil Wiedemann (University of Bonn)
Title: Weak Solutions for the 2D Stationary Euler Equations.
Abstract: We present recent work by A. Choffrut and L. Szekelyhidi on the stationary Euler equations. It is proved that in any L^2-neighbouhood of a smooth solution, there exist infinitely many weak solutions. Surprisingly, this is true even in two dimensions.
• January 30, 2015: Mariusz Mirek (University of Bonn)
Title: Recent developments in discrete harmonic analysis.
Abstract: In recent times - particularly the last two decades - discrete analogues in harmonic analysis have gone through a period of considerable changes and developments. This is due in part to Bourgain's pointwise ergodic theorem for the squares on L^p, (p>1). The main aim of this talk is to discuss recent developments in discrete harmonic analysis. We will be mainly concerned with the discrete maximal functions and singular integral operators along polynomial mappings. We will also discuss two-parameter discrete analogues. All the results are subjects of the ongoing projects with Elias M. Stein, Bartosz Trojan and Jim Wright.
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https://physics.stackexchange.com/questions/41254/why-is-larry-nivens-ringworld-unstable
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# Why is Larry Niven's Ringworld Unstable?
In his 1970 science fiction novel Ringworld, author Larry Niven describes the eponymous Ringworld, a gigantic structure shaped as a ring with a radius of around 1 AU, rotating around a star in the center of the ring. This system is described as physically stable; however many readers have complained that it is actually unstable and the structure will drift away in time.
My first thought reading this is that the Ringworld's center of mass is identical to the star's center of mass, so the system should be stable. Why is it unstable?
Some additional details of the structure:
• Mass: ~1 Solar Mass
• Year duration: ~220 hours
The Ringworld is also made of material strong enough to withstand the stresses affecting it in such a system.
It is only for a spherically symmetric shape that you can treat an extended body as if it were a point mass at the CoM.
The Ringworld is
• stable against axial displacements after which it will gently bob back and forth around the star.
• unstable against transverse ones because the gravitational attraction of the near-side is greater than that of the far-side.
• Why is the gravitational attraction of the near-side larger than that of the far-side? After all, there's more far side, isn't there? – Oak Oct 19 '12 at 20:10
• @Oak "After all, there's more far side, isn't there?" Yes, but there is more in linear proportion to the distance, while the force per unit mass drops by the square of the distance. That is also where spherical shells just balance out: there is more in quadratic proportion to the distance. – dmckee Oct 19 '12 at 20:16
• If your math is up to it, it is best just to work the integrals for a few cases, otherwise it is hard to be really convincing rather than hand-wavy convincing. – dmckee Oct 19 '12 at 21:31
• The first sentence of the answer may be a bit misleading because it implies that a spherical shell such as a Dyson sphere would behave as a point mass at its own center, which would make it stable. Actually the shell theorem says that the sphere's field vanishes on its interior, so the shell's force on the sun is zero. By Newton's third law, the sun's force on the shell is also zero, so this is not a stable equilibrium but a neutral one. – Ben Crowell Apr 7 '13 at 21:02
• I don't think it's necessary to do grotty integrals in order to get a rigorous result. The stability against axial displacements is trivial. Instability against transverse displacements then follows by applying Gauss's law to the field of the ring at its own center. – Ben Crowell Apr 7 '13 at 21:24
http://www.alcyone.com/max/writing/essays/why-niven-rings-are-unstable.html
The short version: a Dyson sphere is stable because even if the sphere gets off-center, there is no net attraction or repulsion (the extra mass of the parts further away help offset any attraction from parts closer to the star).
The ring doesn't have this advantage because, being confined to a plane (mostly), it doesn't have sufficient mass further away to counteract the runaway attraction that would happen if the ring moved off-center.
• The situation with a solid spherical shell is sometimes described as "neutral stability"...if you give it a push it will keep going, but steadily such that to stop it only requires an equivalent push. – dmckee Oct 19 '12 at 19:56
• Actually,isn't light pressure from the star going to be a restoring force? – James Bowery Aug 12 '13 at 17:29
• @JamesBowery No. For the same reason that gravity isn't a restoring force. Both fall by $1/r^2$, so both are subject to the same math. – dmckee Dec 18 '14 at 23:53
Both are unstable (ring and sphere) for the same reason: the potential everywhere inside either one is zero.
This is true for gravitational as well as electrical and magnetic forces, which are all inverse square law / central force situations, and it is that pattern which causes the result.
The proof requires calculus, but is considered an elementary derivation easily done by first-year students in physics or math.
## protected by Qmechanic♦Jul 7 '16 at 17:13
Thank you for your interest in this question. Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
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https://autonomousvision.github.io/smdnets/
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# SMD-Nets: Stereo Mixture Density Networks
## Introduction
Stereo matching indicates the problem of finding dense correspondences in pairs of images in order to perform 3D reconstruction. Recently, deep learning based stereo matching approaches are taking over, becoming one of the best performing methods as witnessed by the leaderboard across different datasets. However, although the performance of CNN-based algorithms has gained great improvement, some difficult problems still exists in the disparity estimation task, in particular:
• Over-smoothing effects at edge boundaries, causing bleeding artifacts in 3D point clouds
• Disparity estimates at pixel locations of a fixed resolution image grid
In the following figure, we illustrate the boundary bleeding problem that characterizes classical deep stereo networks (for clarity we visualize the disparity for a single image row):
We can notice how standard networks for stereo regression predict disparity values at discrete spatial locations and continuously interpolate object boundaries. This effect, which can be observed in the figure below, causes artifacts (i.e. flying pixels) when disparities are converted to point clouds that could be potentially detrimental to subsequent applications such as 3D object detection.
## Our Approach
How can we solve the over-smoothing problem? Our key idea in this project is to alter the output representation adopting a bimodal mixture distribution such that sharp discontinuities can be regressed despite the fact that the underlying neural networks are only able to make smooth predictions. We can visualize this as follows:
In this example, the first mode $&space;(\mu_1,b_1)$ models the background while the second mode $&space;(\mu_2,b_2)$ models the foreground disparity close to the discontinuity. When the probability density (illustrated in gray) of the foreground mode becomes larger than the probability density of the background mode, the most likely disparity sharply transitions from the background to the foreground.
With this simple idea, we are able to produce sharp and accurate depth discontinuities and, thus, notably alleviate bleeding artifacts near object boundaries!
How can we estimate disparities at any continuous spatial location? Also in this case, the solution is straightforward. For every continuous 2D location of the image domain, we bilinearly interpolate the features computed by a standard stereo network and employ a multi-layer perceptron to map the abstract feature representation to the parameters of our bimodal mixture distribution. This strategy allows us to predict disparity maps at arbitrary spatial resolution!
Is this method designed for a specific stereo network? No, it isn’t. Our framework is compatible with a wide class of 2D and 3D stereo architectures existing in the literature. Moreover, it can be effectively adopted for other exciting tasks such as monocular depth estimation and active depth!
## Stereo Super-Resolution
Our continuous formulation allows us to exploit ground truth at higher resolution than the input, which we refer to as stereo super resolution.
Here, a comparison of our model that estimates disparities at 128Mpx (top) and a standard stereo network that predicts disparity maps at 0.5Mpx resolution (bottom), both taking stereo pairs at 0.5 Mpx as input.
## UnrealStereo4K
Motivated by the lack of large-scale, realistic and high-resolution stereo datasets, we introduce a new large-scale synthetic binocular stereo dataset with ground truth disparities at 3840×2160 resolution, comprising photo-realistic renderings of indoor and outdoor environments.
## Results
Some qualitative results of the proposed SMD-Nets using PSMNet as stereo backbone. From left to right, the input image from the UnrealStereo4K test set, the predicted disparity and the corresponding error map.
## Further Information
You can find more information (including the paper and supplementary) on our project page.
If you are interested in experimenting with our approach yourself, you can clone the source code of our project page and train your own models.
@INPROCEEDINGS{Tosi2021CVPR,
author = {Fabio Tosi and Yiyi Liao and Carolin Schmitt and Andreas Geiger},
title = {SMD-Nets: Stereo Mixture Density Networks},
booktitle = {Conference on Computer Vision and Pattern Recognition (CVPR)},
year = {2021}
}
Tags:
Categories:
Updated:
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https://astronomy.stackexchange.com/questions/39626/could-there-really-be-a-preferential-direction-to-the-speed-of-light
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# Could there really be a preferential direction to the speed of light?
This question is inspired by a recent video by Veritasium Why no one has measured the speed of light linked below.
To summarize the video, Derek points out that it is impossible to measure the one-way speed of light, and shows examples of what the consequences of a preferential direction for the speed of light might be.
While the examples given of the measurement problem and consequences all appear valid on local scales, they seem to me to fall apart when you look at the scale of the observable universe. Wouldn't we be able to observe the effects of a preferential direction to the speed of light at cosmological scales? Take the extreme case: the speed of light in one direction is 1/2c and infinite in the opposite direction. If this was true, we should be able to observe the entire universe in the direction where light is approaching us at infinite speed, and see no redshift due to the expansion of the universe (because the photons would reach us instantaneously, there would be no time for the expansion of the universe to stretch them out). Even in less extreme cases, we should still see "more" universe and less redshift in one direction than its opposite.
Since we don't (to my knowledge) observe any difference in the "quantity" of universe (for lack of a better term, feel free to edit if there is a better term for this) in any direction, or any difference in the amount of redshift in any direction, then if there exists a preferential direction to the speed of light, it must be small enough that its effects lie within the error bars for our ability to measure the universe on cosmic scales.
Is my reasoning correct here, or is there some effect I did not take into account that would adjust things so we wouldn't see any difference? (or perhaps my understanding of cosmology is entirely flawed?)
• We also have several fresh questions about this on the Physics stack, eg physics.stackexchange.com/q/590790/123208 Nov 1, 2020 at 0:06
• I just read that question and its answers, and while it is related, I don't think it is a duplicate question, and its answers do not address the specifics of my question. Nov 1, 2020 at 2:13
• Don't worry, we can't close questions as duplicates of questions on other Stack Exchange sites. ;) OTOH, we do often close questions here if they are pure physics with little relevance to astronomy. However, this question has been historically important in astronomy, going back to the determination of the speed of light by Ole Rømer in 1676, using the eclipse data of the Jovian moon Io. So I feel that this question is appropriate on this site. Nov 1, 2020 at 8:58
• I suppose I ought to add that link to the material by John D. Norton on this issue: pitt.edu/~jdnorton/teaching/HPS_0410/chapters/… Hans Reichenbach discusses it extensively in The Philosophy of Space and Time. Nov 1, 2020 at 9:17
Prior to Einstein's 1905 paper, the Lorentz transformation had already been worked out by Lorentz and others. Only their interpretation of it was lacking. They still clung to the idea that there was a Newtonian absolute time, and the times in the Lorentz transform were only apparent times. Einstein was the first to realize that there doesn't need to be a Newtonian time; the Lorentz transform stands perfectly well on its own.
The guy in this video is thinking the same way as Einstein's predecessors; he's an aetherist, though he doesn't realize it. He's stuck to the idea that there's a real time with respect to which the true speed of light is defined, but various "effects" prevent any experiment from actually determining what it is. This is most obvious starting from 11:32, where he says he wants to show how differently the universe works if light is anisotropic, but then shows that it works exactly the same in every experimentally measurable way.
The reality is that only what is operationally measurable matters. What we mean when we say that the speed of light is constant is that there exist coordinates with respect to which it's constant. In a Newtonian corpuscular world, no such coordinates would exist, so the fact that they do exist in the real world is physically meaningful. It's not necessary to use these isotropic coordinates, but it's frequently convenient. That's the only reason we use them. To put it another way, the Einstein synchronization convention really is a convention; it isn't an assumption.
There also exist coordinates with respect to which the speed of light isn't constant. This is not physically meaningful, because no theory could ever avoid them; you can always do a formal substitution of variables, as long as it's invertible and you're consistent about it. The result of any experiment in these coordinates is always the transformation of the result of the experiment in inertial coordinates, because they both describe the same reality.
If $$(x,t)$$ are standard inertial coordinates, then with respect to coordinates $$(x,t')$$ where $$t'=t-x$$, the speed of light $$|dx/dt'|$$ ranges from $$c/2$$ to $$\infty$$ depending on direction. Why don't we see this as an anisotropy in the sky? Because the universe in different directions has aged by different amounts, and their ages differ by just the right amount to compensate for the different light travel times. This is similar to the way that length contraction, the relativity of simultaneity, and so forth always conspire to make things consistent in different inertial frames.
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http://physics.stackexchange.com/questions/53442/has-the-aharonov-bohm-effect-been-experimentally-proven/53478
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# Has The Aharonov-Bohm Effect Been Experimentally Proven?
I have encountered two contradicting papers on the Aharonov-Bohm Effect: One supporting,
The Aharonov-Bohm Effects: Variations on a Subtle Theme. H Batelaan and A Tonomura. Physics Today 62 pp. 38-43 (2009). doi:10.1063/1.3226854, DigitalCommons@UNL.
Does the Aharonov–Bohm Effect Exist? T H Boyer. Foundations of Physics 30 no. 6, pp 893-905 (2000). doi:10.1023/A:1003602524894, direct download from Penn state.
Which one is correct? Has the Aharonov-Bohm effect been experimentally verified?
I e-mailed Timothy H. Boyer, the author who is not convinced of the Aharonov-Bohm effect. He replied,
Although there is excellent experimental evidence for the Aharonov-Bohm phase shift, we still do not know whether this phase shift arises because of a "quantum topological effect" as claimed by Aharonov and Bohm or because of a classical electromagnetic interaction. It is in this sense that I claim that there is still no evidence confirming the quantum topological effect.
I also found a paper by Dr. Boyer which outlines a method for testing which explanation is correct: classical electromagnetism or the quantum topological effect:
Proposed Experimental Test for the Paradoxical Forces Associated with the Aharonov-Bohm Phase Shift. Boyer, Timothy H. Foundations of Physics Letters Vol 19 pp. 491-498 (2006). Abstract | Direct download
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Comment to the question (v1): The 2nd link seems to be broken. – Qmechanic Feb 9 '13 at 8:27
I also find it's a broken link "ERROR: This is an invalid URL. Please reenter the URL, or if you clicked a link in an email message to get here, make sure the link was not split across two lines." Otherwise good question. I always thought the consensus was in favour of Aharonov-Bohm, but criticisms of the experiments should always be taken seriously. – Michael Brown Feb 9 '13 at 8:28
2nd link works here (using Chrome on Windows). The link is link.springer.com/article/10.1023/A:1003602524894 – John Rennie Feb 9 '13 at 8:46
I think it should be this link. – Glen The Udderboat Feb 9 '13 at 8:47
@Gugg The original link is working fine for me. However, while not the same article, it is indeed about the issue discussed in your link, i.e. "is the AB effect a true quantum mechanical $e^{i\phi}$ or does it just look like that because a force has shifted the wavepacket?" – twistor59 Feb 9 '13 at 8:54
I'm pretty sure the answer to that is an emphatic yes: The Aharonov-Bohm effect has been proven many, many times experimentally. My recollection is that it is described as experimentally proven in the Feynman Lectures from way back in the late 1960s. Looking...
Ah, here it is: Volume II, Chapter 15, Section 15-5, "The vector potential and quantum mechanics" (starting on page 15-8), page 15-12, second paragraph from the bottom. The name is misspelled as "Aharanov" in some older editions, incidentally.
That reference likely not a proof, but I know I've seen other very specific, detailed, and far more recent papers and discussion of the effect, including some very nice ones using small lithographically etched circles. I liked that one especially because it make the idea of Aharonov-Bohm as a type of displacement vector easier to visualize. Looking again...
I don't believe this is the same paper I was thinking of, but it's 2008 and pretty similar in testing strategy. Definitely worth a look if you are interested, and likely has relevant references also:
Mesoscopic decoherence in Aharonov-Bohm rings, by A.E. Hansen, A. Kristensen, S. Pedersen, C.B. Sørensen, and P.E. Lindelof. The Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark (February 1, 2008).
And two more for completeness! First, this most excellent paper found by @JoeHobbit (see his comment below) looks like it may be "the paper" that in 1986 -- much later than the Feynman mention -- first provided convincing proof of the existence of Aharonov-Bohm:
Experimental confirmation of Aharonov-Bohm effect using a toroidal magnetic field confined by a superconductor, by Nobuyuki Osakabe, Tsuyoshi Matsuda, Takeshi Kawasaki, Junji Endo, and Akira Tonomura. Phys. Rev. A 34, 815–822 (1986). This classic paper is also available here through scribd, and also here.
For a much more recent example of just how mature this area is these days, there is this 2013 (!) paper on using graphene (I love graphene) to explore Aharonov-Bohm oscillations:
Transport properties of two finite armchair graphene nanoribbons, by Luis Rosales and Jhon W. González. Nanoscale Research Letters 2013, 8:1 doi:10.1186/1556-276X-8-1 (2 January 2013).
(Kudos to Springer for making that and similar papers truly open, by the way!)
2013-02-18. Alas, I've not received any response from Dr Aharonov, though to be honest I thought it unlikely. Worth a try, though; I'd have loved to hear his view.
After going over Timothy Boyer's paper, and in particular after seeing that in 2006 he proposed some specific experiments (inaccessible without paying) to distinguish between relativistic effects and a true Aharonov-Bohm effect, my position is pretty simple: If his experimental setup looks reasonable, someone should should try Boyer's experiment and see what they get.
There is nothing unreasonable about the sequence of first noting possible modeling errors (which is all Boyer is really doing, and doing it pretty well from what I can see), next giving an alternative modeling option that addresses the concerns of the author, and then suggesting an actual experiment to distinguish between the predictions.
Why not just do the experiment? Seems like a good way either to firm up the nature of all Aharonov-Bohm results, or add some interesting new discussion if the experiment produces anything unexpected.
If Boyer's experiment is flawed in concept (again, I cannot see that paper!), can anyone on this group who has seen it say why?
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I have found this article: scribd.com/doc/33717312/… which seems to supportive. – JoeHobbit Feb 9 '13 at 22:08
Good reference! Searching... yes, here's the same paper PDF download format: tallstick.narod.ru/tonomura86.pdf – Terry Bollinger Feb 9 '13 at 22:23
I e-mailed Timothy H. Boyer, the author who remains unconvinced of the Aharonov-Bohm effect. He replied,
Although there is excellent experimental evidence for the Aharonov-Bohm phase shift, we still do not know whether this phase shift arises because of a "quantum topological effect" as claimed by Aharonov and Bohm or because of a classical electromagnetic interaction. It is in this sense that I claim that there is still no evidence confirming the quantum topological effect.
-
Joe Hobbit, thanks for the clarification! I assume the link was still broken when I first looked; downloading now... – Terry Bollinger Feb 10 '13 at 3:30
Should I edit the question to include this info? – JoeHobbit Feb 10 '13 at 3:53
A response from the paper author? Yes indeed I would edit that in! And speaking of that, people tend to forget that Professor Yakir Aharonov continues to publish papers, including one this year already. So... ah, found it... yes, I just emailed Professor Aharonov with a link to Joe Hobbit's question and Boyer's paper. Sure, it's a bit unlikely he'll respond, but there would be zero chance if he did not know about the discussion, yes? Time will tell, it's morning there in a few more hours... – Terry Bollinger Feb 10 '13 at 4:06
@JoeHobbit This comment by H. Boyer definitely clarifies the debate. It's about the (possible) difference between the AB effect and topological quantum effect. I'm nevertheless wondering about the pertinence of Boyer's point of view, since classical electromagnetism is obviously topological in essence. I'll try to check his papers if I have time. – FraSchelle Apr 25 '13 at 22:36
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https://brilliant.org/wiki/regular-polygons-decomposition-into-triangles/
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Regular Polygons - Decomposition into Triangles
Cite as: Regular Polygons - Decomposition into Triangles. Brilliant.org. Retrieved from https://brilliant.org/wiki/regular-polygons-decomposition-into-triangles/
×
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https://mirrors.dotsrc.org/cran/web/packages/propr/vignettes/d_advanced.html
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Introduction
We recognize that this package uses concepts that are not necessarily intuitive. As such, we offer a brief critique of proportionality analysis. Although the user may feel eager to start here, we strongly recommend first reading the companion vignette, “An Introduction to Proportionality”.
Sample data
To facilitate discussion, we simulate count data for 5 features (e.g., genes) labeled “a”, “b”, “c”, “d”, and “e”, as measured across 100 subjects.
library(propr)
N <- 100
a <- seq(from = 5, to = 15, length.out = N)
b <- a * rnorm(N, mean = 1, sd = 0.1)
c <- rnorm(N, mean = 10)
d <- rnorm(N, mean = 10)
e <- rep(10, N)
X <- data.frame(a, b, c, d, e)
Let us assume that these data $$X$$ represent absolute abundance counts (i.e., not relative data). We can build a relative dataset, $$Y$$, by constraining and scaling $$X$$:
Y <- X / rowSums(X) * abs(rnorm(N))
Spurious correlation
Next, we compare pairwise scatterplots for the absolute count data and the corresponding relative count data. We see quickly how these relative data suggest a spurious correlation: although genes “c” and “d” do not correlate with one another absolutely, their relative quantities do.
pairs(X) # absolute data
pairs(Y) # relative data
Spurious correlation is evident by the correlation coefficients too.
suppressWarnings(cor(X)) # absolute correlation
## a b c d e
## a 1.00000000 0.931788181 0.010043731 -0.13955429 NA
## b 0.93178818 1.000000000 0.003598548 -0.14819097 NA
## c 0.01004373 0.003598548 1.000000000 0.06939934 NA
## d -0.13955429 -0.148190975 0.069399336 1.00000000 NA
## e NA NA NA NA 1
cor(Y) # relative correlation
## a b c d e
## a 1.0000000 0.9859307 0.8700492 0.8636699 0.8943947
## b 0.9859307 1.0000000 0.8667073 0.8613842 0.8862515
## c 0.8700492 0.8667073 1.0000000 0.9775640 0.9853551
## d 0.8636699 0.8613842 0.9775640 1.0000000 0.9879143
## e 0.8943947 0.8862515 0.9853551 0.9879143 1.0000000
An in-depth look at VLR
In contrast, the variance of the log-ratios (VLR), defined as the variance of the logarithm of the ratio of two feature vectors, offers a measure of dependence that (a) does not change with respect to the nature of the data (i.e., absolute or relative), and (b) does not change with respect to the number of features included in the computation. As such, the VLR, constituting the numerator portion of the $$\phi$$ metric, and a portion of the $$\rho$$ metric as well, is considered sub-compositionally coherent. Yet, while VLR yields valid results for compositional data, it lacks a meaningful scale.
propr:::proprVLR(Y[, 1:4]) # relative VLR
## a b c d
## a 0.00000000 0.01097609 0.10948053 0.11693487
## b 0.01097609 0.00000000 0.12552455 0.13411702
## c 0.10948053 0.12552455 0.00000000 0.01890533
## d 0.11693487 0.13411702 0.01890533 0.00000000
propr:::proprVLR(X) # absolute VLR
## a b c d e
## a 0.00000000 0.01097609 0.10948053 0.116934874 0.097960496
## b 0.01097609 0.00000000 0.12552455 0.134117023 0.114520860
## c 0.10948053 0.12552455 0.00000000 0.018905334 0.010851192
## d 0.11693487 0.13411702 0.01890533 0.000000000 0.009577957
## e 0.09796050 0.11452086 0.01085119 0.009577957 0.000000000
An in-depth look at clr
In proportionality, we adjust the arbitrarily large VLR by the variance of its individual constituents. To do this, we need to place samples on a comparable scale. Log-ratio transformation, such as the centered log-ratio (clr) transformation, shifts the data onto a “standardized” scale that allows us to compare differences in the VLR-matrix.
In the next figures, we compare pairwise scatterplots for the clr-transformed absolute count data and the corresponding clr-transformed relative count data. While equivalent, we see a relationship between “c” and “d” that should not exist based on what we know from the non-transformed absolute count data. This demonstrates that, although the clr-transformation helps us compare values across samples, it does not rescue information lost by making absolute data relative.
pairs(propr:::proprCLR(Y[, 1:4])) # relative clr-transformation
pairs(propr:::proprCLR(X)) # absolute clr-transformation
Proportionality is a compromise between the advantages of VLR and the disadvantages of clr to establish a measure of dependence that is robust yet interpretable. As such, spurious proportionality is possible when the clr does not adequately approximate an ideal reference.
propr(Y[, 1:4])@matrix # relative proportionality with clr
## a b c d
## a 1.0000000 0.8244107 -0.8768141 -0.8756131
## b 0.8244107 1.0000000 -0.8836297 -0.8982919
## c -0.8768141 -0.8836297 1.0000000 0.7156007
## d -0.8756131 -0.8982919 0.7156007 1.0000000
propr(X)@matrix # absolute proportionality with clr
## a b c d e
## a 1.0000000 0.8696275 -0.8211907 -0.8540631 -0.8227045
## b 0.8696275 1.0000000 -0.7913625 -0.8365445 -0.7977623
## c -0.8211907 -0.7913625 1.0000000 0.6137942 0.7261633
## d -0.8540631 -0.8365445 0.6137942 1.0000000 0.7750662
## e -0.8227045 -0.7977623 0.7261633 0.7750662 1.0000000
An in-depth look at alr
The additive log-ratio (alr) adjusts each subject vector by the value of one its own components, chosen as a reference. If we select as a reference some feature $$D$$ with an a priori known fixed absolute count across all subjects, we can effectively “back-calculate” absolute data from relative data. When initially crafting the data $$X$$, we included “e” as this fixed value.
The following figures compare pairwise scatterplots for alr-transformed relative count data (i.e., $$\textrm{alr}(Y)$$ with “e” as the reference) and the corresponding absolute count data. We see here how the alr-transformation can eliminate the spurious correlation between “c” and “d”.
pairs(propr:::proprALR(Y, ivar = 5)) # relative alr
pairs(X[, 1:4]) # absolute data
Again, this gets reflected in the results of propr when we select “e” as the reference.
propr(Y, ivar = 5)@matrix # relative proportionality with alr
## a b c d e
## a 1.000000000 0.948343298 -0.006146749 -0.08737732 0
## b 0.948343298 1.000000000 -0.001216405 -0.08072766 0
## c -0.006146749 -0.001216405 1.000000000 0.07459021 0
## d -0.087377319 -0.080727657 0.074590210 1.00000000 0
## e 0.000000000 0.000000000 0.000000000 0.00000000 1
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http://ogi-software.com/Default
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WISPP Finite Element Model
Wave Induced Stresses and Pore Pressures
Wave Induced Stresses and Pore Pressures (WISPP) is a one dimensional finite element model!
Written by Dr. Stephen Thomas at Oxford Geotechnica International. Based on work at the Soil Mechanics Group, Oxford University, Department of Engneering Science.
## What is WISPP?
The numerical model WISPP (Wave Induced Stresses and Pore Pressures) is a hybrid Finite Element – Analytical Model developed to simulate the time and spatially dependent stresses, pore pressures and soil displacements in a seabed when subject to sinusoidal wave loading.
The model simulates a sinusoidal wave loading on a seabed soil of finite thickness, with the vertical domain discretized in to 300 elements. The variability in the direction of wave travel, and the variability with time is simulated using analytical methods using complex number mathematics, i.e. real and imaginary conditions.
### WISPP Governing Equations
If you are using google chrome, please install the MathJax Extension
The model simulates the two-dimensional plane strain Biot equations of soil displacement and pore pressure in the vertical (z) and horizontal (x) directions, together with variability in time (t). The governing equations solved are as follows:
from equilibrium in the x direction,
(lambda + 2G)(del^2w_x)/(del x^2) + G (del^2w_x)/(delz^2) + lambda (del^2 w_z)/(delxdelz) + G(del^2w_z)/(delzdelx) - (delu_w)/(delx) = 0
from equilibrium in the z direction,
(lambda + 2G)(del^2w_z)/(del z^2) + G (del^2w_z)/(delx^2) + lambda (del^2 w_x)/(delzdelx) + G(del^2w_x)/(delxdelz) - (delu_w)/(delz) = 0
and from continuity principles incorporating Darcy's Law of fluid flow through a deformable porous medium
del/(delx)[(k_(x x))/(gamma_w)(delu_w)/(delx) + (k_(xz))/(gamma_w)(delu_w)/(delz)] + del/(delz)[(k_(z x))/(gamma_w)(delu_w)/(delx) + (k_(zz))/(gamma_w)(delu_w)/(delz)] = C(delu_w)/(delt) + del/(delt)[(delw_x)/(delx) + (delw_z)/(delz)]
The variation in time (t) and horizontal distance (x) is simulated in real and imaginary space:
w_x(x, z, t,) = barw_x(z) exp[i(ax - omegat)]
w_z(x, z, t,) = barw_z(z) exp[i(ax - omegat)]
u_w(x, z, t,) = baru_w(z) exp[i(ax - omegat)]
Resulting in the governing equation in real and imaginary conditions:
from equilibrium in the x direction,
-a^2(lambda+2G)w_x + G(del^2w_x)/(delz^2) + ia(lambda + G) (delw_z)/(delz) - iau_w = 0
From equilibrium in the z direction,
(lambda +2G)(del^2w_z)/(delz^2) - a^2Gw_z + ia(lambda +2G)(delw_x)/(delz) - (delu_w)/(delz) = 0
and from the continuity equation and Darcy's Law.
-a^2(k_(x x))/(gamma_w)u_w + (k_(zz))/(gamma_w)(del^2u_w)/(delz^2) + ia(k_(xz))/(gamma_w)(delu_w)/(delz) + ia(k_(zx))/(gamma_w)(delu_w)/(delz) = - iomegaCu_w + aomegaw_x - iomega(delw_z)/(delz)
x horizontal axis (m) z depth into the seabed (m) t time (s) T wave period (s) L wavelength (m) lambda Lame's elastic constant (kPa) G elastic shear modulus (kPa) K drained bulk modulus (kPa)
C compressibility coefficient (kPa-1) k coefficient of permeability (m s-1) gamma_w specific weight of water (kNm-3) w_x total displacement in the horizontal direction (m) w_z total displacement in the vertical direction (m) u_w pore water pressure (kPa)
P_0 pressure wave amplitude (kPa) a wavenumber ((2pi)/L) (1/m) omega angular velocity ((2pi)/T) (1/s) i imaginary unit (sqrt(-1))
### Background
Dynamic wave loading on the seabed originates as a surface water wave that propagates along the water surface. A certain proportion of the energy held by this wave will be transferred down through the water and will be felt on the seabed as a dynamic load as the wave passes overhead. The proportion of wave energy that reaches the seabed will be controlled by the wavelength and the water depth. To the designer of the foundation of an offshore structure, it is essential that the behaviour of the seabed under wave loading is understood before a safe design can be made.
Two main conditions must be considered in regard to the wave loading. The first, most obvious, is to evaluate the maximum stress envelope throughout the soil domain. To obtain this, the maximum wave induced stresses must be added to those stresses caused by the deployment of the proposed structure. The second condition that must be be considered is the reduction in soil strength due to the generation of pore water pressures, which occurs due to repeated cyclic loading on a soil. The magnitude of the pore water pressures generated will depend upon a number of factors, including the amplitude of the soil stress and the frequency and duration of loading. In addition, the soil permeability is important as this controls the rate at which the generated pore water pressures dissipate.
For the above conditions, it is often necessary to evaluate the wave induced stresses, displacements and pore pressures in a saturated or unsaturated seabed with the variable material properties and initial conditions.
## WISPP Inputs
Default values have been provided to get you started with WISPP
Title
Text
Wavelength (L)
m
Wave Period (T)
s
Drained Shear Modulus of Soil (G)
kPa
Drained Bulk Modulus of Soil (K)
kPa
Seabed Thickness (D)
m
Pressure Wave Amplitude on the Seabed (P0)
kPa
Compressibility of Pore Fluid (cf)
kPa-1
Soil Porosity (∅)
decimal
Weight Density of Pore Fluid (γf)
kNm-3
Horizontal Coefficient of Permeability (kx)
m s-1
Vertical Coefficient of Permeability (kz)
m s-1
### Seafloor Characteristics
Choose either Permeable or Impermeable
### Sediment Base Characteristics
The base of the sediment is modelled as rough
## Wispp Output
Wispp outputs 20 columns of data for 300 elements.
You can view the results from WISPP in the graphs below.
Alternativley you can download the data in an excel template. This will give you more control over the graphs.
The data column headings are described below.
You will need to enable active content in the excel workbook to allow easy navigation between the graphs.
### Graphs
View the graphs for Maximum Diplacement, Horizontal Displacement and Vertical Displacement
View the graphs for Deviator Stress, Horizontal Effective Stress, Vertical Effective Stress, and Vertical minus Horizontal Effective Stress
View the graphs for Pressure Modulus and Pore Water Pressure
### Disclamier
OGI's Software is for teaching and research purposes only
Software used on the OGI website is provided 'as is' without warranty of any kind, either express or implied, including, but not limited to, the implied warranties of fitness for a purpose, or the warranty of non-infringement. Without limiting the foregoing, OGI makes no warranty that:
i).the software will meet your requirements
ii).the software will be uninterrupted, timely, secure or error-free
iii).the results that may be obtained from the use of the software will be effective, accurate or reliable
iv).the quality of the software will meet your expectations
v).any errors in the software obtained from the OGI web site will be corrected.
Software and its documentation made available on the OGI web site: vi).could include technical or other mistakes, inaccuracies or typographical errors. OGI may make changes to the software or documentation made available on its web site.
vii).may be out of date, and OGI makes no commitment to update such materials.
OGI assumes no responsibility for errors or omissions in the software or documentation available from its web site.
In no event shall OGI be liable to you or any third parties for any special, punitive, incidental, indirect or consequential damages of any kind, or any damages whatsoever, including, without limitation, those resulting from loss of use, data or profits, whether or not the OGI has been advised of the possibility of such damages, and on any theory of liability, arising out of or in connection with the use of this software.
The use of the software on the OGI web site is done at your own discretion and risk and with agreement that you will be solely responsible for any damage to your computer system or loss of data that results from such activities. No advice or information, whether oral or written, obtained by you from OGI or from the OGI web site shall create any warranty for the software.
© 2018 - OGI Groundwater Specialists Limited 2015
Tel: 0191 378 7010
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https://www.ideals.illinois.edu/handle/2142/100786
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## Files in this item
FilesDescriptionFormat
application/pdf
1083751.pdf (9MB)
PresentationPDF
application/pdf
2953.pdf (22kB)
AbstractPDF
## Description
Title: LINE INTENSITY MEASUREMENTS AND ANALYSIS IN THE ν3 BAND OF RUTHENIUM TETROXIDE Author(s): Vander Auwera, Jean Contributor(s): Manceron, Laurent; Doizi, Denis; Boudon, Vincent; Reymond-Laruinaz, Sébastien Subject(s): Small molecules Abstract: Ruthenium tetroxide (RuO$_4$) is a heavy tetrahedral molecule characterized by an unusual volatility near ambient temperature. Because of its chemical toxicity and the radiological impact of its $^{103}$Ru and $^{106}$Ru isotopologues, the possible remote sensing of this compound in the atmosphere has renewed interest in its spectroscopic properties. In a recent study, the strong fundamental band associated with the excitation of the infrared active stretching mode $\nu_3$ of $^{102}$Ru$^{16}$O$_4$, observed near 10 $\mu$m, was re-investigated at high-resolution (0.001 cm$^{-1}$) with the help of a $^{102}$Ru isotopically pure sample.\footnote{S. Reymond-Laruinaz, V. Boudon, L. Manceron, L. Lago, D. Doizi, J Mol Spectrosc 315 (2015) 46--54.} Building upon that work, the present contribution is the first investigation dealing with high-resolution line-by-line intensity measurements for the $\nu_3$ fundamental band of $^{102}$Ru$^{16}$O$_4$. It relies on high resolution Fourier transform infrared spectra specifically recorded at room temperature at the AILES beam line of SOLEIL using synchrotron radiation, a specially constructed cell and an isotopically pure sample of $^{102}$Ru$^{16}$O$_4$. Relying on an effective Hamiltonian and associated effective dipole moment,$^{a}$ the measured line intensities were assigned and dipole moment parameters determined. A HITRAN-formatted frequency and intensity line list was generated. Issue Date: 06/20/18 Publisher: International Symposium on Molecular Spectroscopy Citation Info: APS Genre: Conference Paper / Presentation Type: Text Language: English URI: http://hdl.handle.net/2142/100786 DOI: 10.15278/isms.2018.WH08 Other Identifier(s): WH08 Date Available in IDEALS: 2018-08-172018-12-12
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http://mathhelpforum.com/algebra/13079-divide-frac-whole-numb.html
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# Math Help - Divide Frac by whole numb
1. ## Divide Frac by whole numb
4 3/5 divided by 5 please solve and explain how it was done.
4 3/5 divided by 5 please solve and explain how it was done.
ok, when we are dividing fractions, what we do is that we take the inverse of the fraction on the bottom (meaning i just flip it upside down) and multiply it by the top, and that's our solution
e.g. (2/3) / (4/5) = (2/3) * (5/4) = 5/6
when dividing by whole numbers, its the same principle. think of any whole number as itself over 1. so think of 5 as 5/1, or 9 as 9/1, so
e.g. (2/3) / 9 = (2/3) / (9/1) = (2/3) * (1/9) = 2/27
now to your problem. the first thing we have to do is change 4 3/5 to an improper fraction (i hope you know how to do that), the result is 23/5
so now, (23/5) / 5 = (23/5) / (5/1) = (23/5)*(1/5) = 23/25
3. Yes, I just forgot.
Thanks.
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