Science.gov

Sample records for excursion set model

  1. Excursion set peaks: a self-consistent model of dark halo abundances and clustering

    NASA Astrophysics Data System (ADS)

    Paranjape, Aseem; Sheth, Ravi K.; Desjacques, Vincent

    2013-05-01

    We describe how to extend the excursion set peaks framework so that its predictions of dark halo abundances and clustering can be compared directly with simulations. These extensions include: a halo mass definition which uses the TopHat filter in real space; the mean dependence of the critical density for collapse δc on halo mass m; and the scatter around this mean value. All three of these are motivated by the physics of triaxial rather than spherical collapse. A comparison of the resulting mass function with N-body results shows that, if one uses δc(m) and its scatter as determined from simulations, then all three are necessary ingredients for obtaining ˜10 per cent accuracy. For example, assuming a constant value of δc with no scatter, as motivated by the physics of spherical collapse, leads to many more massive haloes than seen in simulations. The same model is also in excellent agreement with N-body results for the linear halo bias, especially at the high mass end where the traditional peak-background split argument applied to the mass function fit is known to underpredict the measured bias by ˜10 per cent. In the excursion set language, our model is about walks centred on special positions (peaks) in the initial conditions - we discuss what it implies for the usual calculation in which all walks contribute to the statistics.

  2. Excursion-Set-Mediated Genetic Algorithm

    NASA Technical Reports Server (NTRS)

    Noever, David; Baskaran, Subbiah

    1995-01-01

    Excursion-set-mediated genetic algorithm (ESMGA) is embodiment of method of searching for and optimizing computerized mathematical models. Incorporates powerful search and optimization techniques based on concepts analogous to natural selection and laws of genetics. In comparison with other genetic algorithms, this one achieves stronger condition for implicit parallelism. Includes three stages of operations in each cycle, analogous to biological generation.

  3. Excursion-Set-Mediated Genetic Algorithm

    NASA Technical Reports Server (NTRS)

    Noever, David; Baskaran, Subbiah

    1995-01-01

    Excursion-set-mediated genetic algorithm (ESMGA) is embodiment of method of searching for and optimizing computerized mathematical models. Incorporates powerful search and optimization techniques based on concepts analogous to natural selection and laws of genetics. In comparison with other genetic algorithms, this one achieves stronger condition for implicit parallelism. Includes three stages of operations in each cycle, analogous to biological generation.

  4. An Excursion Set Model of the Cosmic Web: the Abundance of Sheets, Filaments And Halos

    SciTech Connect

    Shen, Jiajian; Abel, Tom; Mo, Houjun; Sheth, Ravi; /Pennsylvania U.

    2006-01-11

    We discuss an analytic approach for modeling structure formation in sheets, filaments and knots. This is accomplished by combining models of triaxial collapse with the excursion set approach: sheets are defined as objects which have collapsed along only one axis, filaments have collapsed along two axes, and halos are objects in which triaxial collapse is complete. In the simplest version of this approach, which we develop here, large scale structure shows a clear hierarchy of morphologies: the mass in large-scale sheets is partitioned up among lower mass filaments, which themselves are made-up of still lower mass halos. Our approach provides analytic estimates of the mass fraction in sheets, filaments and halos, and its evolution, for any background cosmological model and any initial fluctuation spectrum. In the currently popular {Lambda}CDM model, our analysis suggests that more than 99% of the mass in sheets, and 72% of the mass in filaments, is stored in objects more massive than 10{sup 10}M{sub {circle_dot}} at the present time. For halos, this number is only 46%. Our approach also provides analytic estimates of how halo abundances at any given time correlate with the morphology of the surrounding large-scale structure, and how halo evolution correlates with the morphology of large scale structure.

  5. Stochastic bias in multidimensional excursion set approaches

    NASA Astrophysics Data System (ADS)

    Castorina, Emanuele; Sheth, Ravi K.

    2013-08-01

    We describe a simple fully analytic model of the excursion set approach associated with two Gaussian random walks: the first walk represents the initial overdensity around a protohalo, and the second is a crude way of allowing for other factors which might influence halo formation. This model is richer than that based on a single walk, because it yields a distribution of heights at first crossing. We provide explicit expressions for the unconditional first crossing distribution which is usually used to model the halo mass function, the progenitor distributions from which merger rates are usually estimated and the conditional distributions from which correlations with environment are usually estimated. These latter exhibit perhaps the simplest form of what is often called non-local bias, and which we prefer to call stochastic bias, since the new bias effects arise from `hidden variables' other than density, but these may still be defined locally. We provide explicit expressions for these new bias factors. We also provide formulae for the distribution of heights at first crossing in the unconditional and conditional cases. In contrast to the first crossing distribution, these are exact, even for moving barriers, and for walks with correlated steps. The conditional distributions yield predictions for the distribution of halo concentrations at fixed mass and formation redshift. They also exhibit assembly bias like effects, even when the steps in the walks themselves are uncorrelated. Our formulae show that without prior knowledge of the physical origin of the second walk, the naive estimate of the critical density required for halo formation which is based on the statistics of the first crossing distribution will be larger than that based on the statistical distribution of walk heights at first crossing; both will be biased low compared to the value associated with the physics. Finally, we show how the predictions are modified if we add the requirement that haloes form

  6. Excursion set theory for correlated random walks

    NASA Astrophysics Data System (ADS)

    Farahi, Arya; Benson, Andrew J.

    2013-08-01

    We present a new method to compute the first crossing distribution in excursion set theory for the case of correlated random walks. We use a combination of the path integral formalism of Maggiore & Riotto, and the integral equation solution of Zhang & Hui and Benson et al. to find a numerically and convenient algorithm to derive the first crossing distribution. We apply this methodology to the specific case of a Gaussian random density field filtered with a Gaussian smoothing function. By comparing our solutions to results from Monte Carlo calculations of the first crossing distribution we demonstrate that approximately it is in good agreement with exact solution for certain barriers, and at large masses. Our approach is quite general, and can be adapted to other smoothing functions and barrier function and also to non-Gaussian density fields.

  7. Non-Gaussianity and Excursion Set Theory: Halo Bias

    SciTech Connect

    Adshead, Peter; Baxter, Eric J.; Dodelson, Scott; Lidz, Adam

    2012-09-01

    We study the impact of primordial non-Gaussianity generated during inflation on the bias of halos using excursion set theory. We recapture the familiar result that the bias scales as $k^{-2}$ on large scales for local type non-Gaussianity but explicitly identify the approximations that go into this conclusion and the corrections to it. We solve the more complicated problem of non-spherical halos, for which the collapse threshold is scale dependent.

  8. Inflationary field excursion in broad classes of scalar field models

    NASA Astrophysics Data System (ADS)

    Banerjee, Argha; Koley, Ratna

    2016-12-01

    In single-field slow-roll inflation models, the height and slope of the potential are made to satisfy certain conditions to match with observations. This in turn translates into bounds on the number of e -foldings and the excursion of the scalar field during inflation. In this work we consider broad classes of inflationary models to study how much the field excursion starting from the horizon exit to the end of inflation, Δ ϕ , can vary for the set of inflationary parameters given by Planck. We also derive an upper bound on the number of e -foldings between the horizon exit of a cosmologically interesting mode and the end of inflation. We comment on the possibility of having super-Planckian and sub-Planckian field excursions within the framework of single-field slow-roll inflation.

  9. Excursion sets and non-Gaussian void statistics

    SciTech Connect

    D'Amico, Guido; Musso, Marcello; Paranjape, Aseem; Norena, Jorge

    2011-01-15

    Primordial non-Gaussianity (NG) affects the large scale structure (LSS) of the Universe by leaving an imprint on the distribution of matter at late times. Much attention has been focused on using the distribution of collapsed objects (i.e. dark matter halos and the galaxies and galaxy clusters that reside in them) to probe primordial NG. An equally interesting and complementary probe however is the abundance of extended underdense regions or voids in the LSS. The calculation of the abundance of voids using the excursion set formalism in the presence of primordial NG is subject to the same technical issues as the one for halos, which were discussed e.g. in Ref. [51][G. D'Amico, M. Musso, J. Norena, and A. Paranjape, arXiv:1005.1203.]. However, unlike the excursion set problem for halos which involved random walks in the presence of one barrier {delta}{sub c}, the void excursion set problem involves two barriers {delta}{sub v} and {delta}{sub c}. This leads to a new complication introduced by what is called the 'void-in-cloud' effect discussed in the literature, which is unique to the case of voids. We explore a path integral approach which allows us to carefully account for all these issues, leading to a rigorous derivation of the effects of primordial NG on void abundances. The void-in-cloud issue, in particular, makes the calculation conceptually rather different from the one for halos. However, we show that its final effect can be described by a simple yet accurate approximation. Our final void abundance function is valid on larger scales than the expressions of other authors, while being broadly in agreement with those expressions on smaller scales.

  10. STATISTICS OF DARK MATTER HALOS FROM THE EXCURSION SET APPROACH

    SciTech Connect

    Lapi, A.; Salucci, P.; Danese, L.

    2013-08-01

    We exploit the excursion set approach in integral formulation to derive novel, accurate analytic approximations of the unconditional and conditional first crossing distributions for random walks with uncorrelated steps and general shapes of the moving barrier; we find the corresponding approximations of the unconditional and conditional halo mass functions for cold dark matter (DM) power spectra to represent very well the outcomes of state-of-the-art cosmological N-body simulations. In addition, we apply these results to derive, and confront with simulations, other quantities of interest in halo statistics, including the rates of halo formation and creation, the average halo growth history, and the halo bias. Finally, we discuss how our approach and main results change when considering random walks with correlated instead of uncorrelated steps, and warm instead of cold DM power spectra.

  11. On the area of excursion sets of spherical Gaussian eigenfunctions

    NASA Astrophysics Data System (ADS)

    Marinucci, Domenico; Wigman, Igor

    2011-09-01

    The high frequency behaviour for random eigenfunctions of the spherical Laplacian has been recently the object of considerable interest, also because of strong motivation arising from physics and cosmology. In this paper, we are concerned with the high frequency behaviour of excursion sets; in particular, we establish a uniform central limit theorem for the empirical measure, i.e., the proportion of spherical surface, where spherical Gaussian eigenfunctions lie below a level z. Our proofs borrow some techniques from the literature on stationary long memory processes; in particular, we expand the empirical measure into Hermite polynomials, and establish a uniform weak reduction principle, entailing that the asymptotic behaviour is asymptotically dominated by a single term in the expansion. As a result, we establish a functional central limit theorem; the limiting process is fully degenerate.

  12. Modeling the effects of storage temperature excursions on shelf life.

    PubMed

    Socarras, Sandy; Magari, Robert T

    2009-02-20

    Excursions from storage condition requirements may affect product performance and stability. The effects of temperature excursion on stability depend on the amount of time that a product is subjected to these conditions, temperature level, and activation energy. Both time at elevated temperature and the temperature level can be directly measured, while activation energy needs to be estimated from the accelerated stability tests. Coulter Clenz reagent degradation information is used to demonstrate the effects of temperature excursions. The stability of the product is affected by any excursion, but Coulter Clenz will not lose all of its stability for excursion of up to 30 days at 35 degrees C and 20 days at 40 degrees C. Temperature excursion for up to 20 days at 40 degrees C will reduce the stability of a product that has activation energy in the range of 26-30kcalmol(-1) approximately by 5-7 months. Products with lower activation energy will have a significantly lower reduction in stability. The effects of excursions on shelf life performance are less severe when lower level of risk is implemented to establish the claimed shelf life. The proposed model can effectively predict temperature excursion if used within the scope of a product performance and its characteristics.

  13. Testing the self-consistency of the excursion set approach to predicting the dark matter halo mass function.

    PubMed

    Achitouv, I; Rasera, Y; Sheth, R K; Corasaniti, P S

    2013-12-06

    The excursion set approach provides a framework for predicting how the abundance of dark matter halos depends on the initial conditions. A key ingredient of this formalism is the specification of a critical overdensity threshold (barrier) which protohalos must exceed if they are to form virialized halos at a later time. However, to make its predictions, the excursion set approach explicitly averages over all positions in the initial field, rather than the special ones around which halos form, so it is not clear that the barrier has physical motivation or meaning. In this Letter we show that once the statistical assumptions which underlie the excursion set approach are considered a drifting diffusing barrier model does provide a good self-consistent description both of halo abundance as well as of the initial overdensities of the protohalo patches.

  14. Statistics of dark matter halos in the excursion set peak framework

    SciTech Connect

    Lapi, A.; Danese, L. E-mail: danese@sissa.it

    2014-07-01

    We derive approximated, yet very accurate analytical expressions for the abundance and clustering properties of dark matter halos in the excursion set peak framework; the latter relies on the standard excursion set approach, but also includes the effects of a realistic filtering of the density field, a mass-dependent threshold for collapse, and the prescription from peak theory that halos tend to form around density maxima. We find that our approximations work excellently for diverse power spectra, collapse thresholds and density filters. Moreover, when adopting a cold dark matter power spectra, a tophat filtering and a mass-dependent collapse threshold (supplemented with conceivable scatter), our approximated halo mass function and halo bias represent very well the outcomes of cosmological N-body simulations.

  15. Peaks and dips in Gaussian random fields: a new algorithm for the shear eigenvalues, and the excursion set theory

    NASA Astrophysics Data System (ADS)

    Rossi, Graziano

    2013-04-01

    We present a new algorithm to sample the constrained eigenvalues of the initial shear field associated with Gaussian statistics, called the `peak/dip excursion-set-based' algorithm, at positions which correspond to peaks or dips of the correlated density field. The computational procedure is based on a new formula which extends Doroshkevich's unconditional distribution for the eigenvalues of the linear tidal field, to account for the fact that haloes and voids may correspond to maxima or minima of the density field. The ability to differentiate between random positions and special points in space around which haloes or voids may form (i.e. peaks/dips), encoded in the new formula and reflected in the algorithm, naturally leads to a straightforward implementation of an excursion set model for peaks and dips in Gaussian random fields - one of the key advantages of this sampling procedure. In addition, it offers novel insights into the statistical description of the cosmic web. As a first physical application, we show how the standard distributions of shear ellipticity and prolateness in triaxial models of structure formation are modified by the constraint. In particular, we provide a new expression for the conditional distribution of shape parameters given the density peak constraint, which generalizes some previous literature work. The formula has important implications for the modelling of non-spherical dark matter halo shapes, in relation to their initial shape distribution. We also test and confirm our theoretical predictions for the individual distributions of eigenvalues subjected to the extremum constraint, along with other directly related conditional probabilities. Finally, we indicate how the proposed sampling procedure naturally integrates into the standard excursion set model, potentially solving some of its well-known problems, and into the ellipsoidal collapse framework. Several other ongoing applications and extensions, towards the development of

  16. Experimental verification of theoretical model for speckle intensity excursion areas

    SciTech Connect

    Alexander, T.L.; Harvey, J.E.; Hefele, D.

    1994-12-31

    Speckle is inherently an interference phenomenon produced when a rough object or turbulent medium introduces some degree of randomness to a reflected or transmitted electromagnetic field. Speckle characteristics are therefore a major concern in many laser imaging or wave propagation applications. For many applications, a detailed description of speckle size as a function of intensity threshold level is desirable. Extensive experimental measurements of average speckle size as a function of intensity threshold level were therefore made for several different targets and illumination conditions. The authors then compare these measurements with a theoretical model for excursion areas of speckle intensity. Excellent agreement is obtained for intensity threshold levels greater than approximately twice the mean intensity level.

  17. Constrained simulations and excursion sets: understanding the risks and benefits of `genetically modified' haloes

    NASA Astrophysics Data System (ADS)

    Porciani, Cristiano

    2016-12-01

    Constrained realizations of Gaussian random fields are used in cosmology to design special initial conditions for numerical simulations. We review this approach and its application to density peaks providing several worked-out examples. We then critically discuss the recent proposal to use constrained realizations to modify the linear density field within and around the Lagrangian patches that form dark-matter haloes. The ambitious concept is to forge `genetically modified' haloes with some desired properties after the non-linear evolution. We demonstrate that the original implementation of this method is not exact but approximate because it tacitly assumes that protohaloes sample a set of random points with a fixed mean overdensity. We show that carrying out a full genetic modification is a formidable and daunting task requiring a mathematical understanding of what determines the biased locations of protohaloes in the linear density field. We discuss approximate solutions based on educated guesses regarding the nature of protohaloes. We illustrate how the excursion-set method can be adapted to predict the non-linear evolution of the modified patches and thus fine tune the constraints that are necessary to obtain pre-selected halo properties. This technique allows us to explore the freedom around the original algorithm for genetic modification. We find that the quantity which is most sensitive to changes is the halo mass-accretion rate at the mass scale on which the constraints are set. Finally, we discuss constraints based on the protohalo angular momenta.

  18. Matrix formalism of excursion set theory: A new approach to statistics of dark matter halo counting

    NASA Astrophysics Data System (ADS)

    Nikakhtar, Farnik; Baghram, Shant

    2017-08-01

    Excursion set theory (EST) is an analytical framework to study the large-scale structure of the Universe. EST introduces a procedure to calculate the number density of structures by relating the cosmological linear perturbation theory to the nonlinear structures in late time. In this work, we introduce a novel approach to reformulate the EST in matrix formalism. We propose that the matrix representation of EST will facilitate the calculations in this framework. The method is to discretize the two-dimensional plane of variance and density contrast of EST, where the trajectories for each point in the Universe lived there. The probability of having a density contrast in a chosen variance is represented by a probability ket. Naturally, the concept of the transition matrix pops up to define the trajectories. We also define the probability transition rate which is used to obtain the first up-crossing of trajectories and the number count of the structures. In this work we show that the discretization let us study the non-Markov processes by forcing them to look like a Wiener process. Also we discuss that the zero drift processes with Gaussian and also non-Gaussian initial conditions can be studied by this formalism. The continuous limit of the formalism is discussed, and the known Fokker-Planck dispersion equation is recovered. Finally we show that the probability of the most massive progenitors can be extracted in this framework.

  19. Scalar excursions in large-eddy simulations

    NASA Astrophysics Data System (ADS)

    Matheou, Georgios; Dimotakis, Paul E.

    2016-12-01

    The range of values of scalar fields in turbulent flows is bounded by their boundary values, for passive scalars, and by a combination of boundary values, reaction rates, phase changes, etc., for active scalars. The current investigation focuses on the local conservation of passive scalar concentration fields and the ability of the large-eddy simulation (LES) method to observe the boundedness of passive scalar concentrations. In practice, as a result of numerical artifacts, this fundamental constraint is often violated with scalars exhibiting unphysical excursions. The present study characterizes passive-scalar excursions in LES of a shear flow and examines methods for diagnosis and assesment of the problem. The analysis of scalar-excursion statistics provides support of the main hypothesis of the current study that unphysical scalar excursions in LES result from dispersive errors of the convection-term discretization where the subgrid-scale model (SGS) provides insufficient dissipation to produce a sufficiently smooth scalar field. In the LES runs three parameters are varied: the discretization of the convection terms, the SGS model, and grid resolution. Unphysical scalar excursions decrease as the order of accuracy of non-dissipative schemes is increased, but the improvement rate decreases with increasing order of accuracy. Two SGS models are examined, the stretched-vortex and a constant-coefficient Smagorinsky. Scalar excursions strongly depend on the SGS model. The excursions are significantly reduced when the characteristic SGS scale is set to double the grid spacing in runs with the stretched-vortex model. The maximum excursion and volume fraction of excursions outside boundary values show opposite trends with respect to resolution. The maximum unphysical excursions increase as resolution increases, whereas the volume fraction decreases. The reason for the increase in the maximum excursion is statistical and traceable to the number of grid points (sample size

  20. THE HALO MASS FUNCTION FROM EXCURSION SET THEORY. I. GAUSSIAN FLUCTUATIONS WITH NON-MARKOVIAN DEPENDENCE ON THE SMOOTHING SCALE

    SciTech Connect

    Maggiore, Michele; Riotto, Antonio

    2010-03-10

    A classic method for computing the mass function of dark matter halos is provided by excursion set theory, where density perturbations evolve stochastically with the smoothing scale, and the problem of computing the probability of halo formation is mapped into the so-called first-passage time problem in the presence of a barrier. While the full dynamical complexity of halo formation can only be revealed through N-body simulations, excursion set theory provides a simple analytic framework for understanding various aspects of this complex process. In this series of papers we propose improvements of both technical and conceptual aspects of excursion set theory, and we explore up to which point the method can reproduce quantitatively the data from N-body simulations. In Paper I of the series, we show how to derive excursion set theory from a path {integral} formulation. This allows us both to derive rigorously the absorbing barrier boundary condition, that in the usual formulation is just postulated, and to deal analytically with the non-Markovian nature of the random walk. Such a non-Markovian dynamics inevitably enters when either the density is smoothed with filters such as the top-hat filter in coordinate space (which is the only filter associated with a well-defined halo mass) or when one considers non-Gaussian fluctuations. In these cases, beside 'Markovian' terms, we find 'memory' terms that reflect the non-Markovianity of the evolution with the smoothing scale. We develop a general formalism for evaluating perturbatively these non-Markovian corrections, and in this paper we perform explicitly the computation of the halo mass function for Gaussian fluctuations, to first order in the non-Markovian corrections due to the use of a top-hat filter in coordinate space. In Paper II of this series we propose to extend excursion set theory by treating the critical threshold for collapse as a stochastic variable, which better captures some of the dynamical complexity of

  1. Preliminary Landing Tests of a 1/6-Scale Dynamic Model of a Lunar Excursion Vehicle

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Preliminary Landing Tests of a 1/6-Scale Dynamic Model of a Lunar Excursion Vehicle. The film shows 21 trials made on 8 days of the scale Model 413 lunar landing vehicle. Attitudes tested were a pitch of 0, -15, or 15 degrees and yaw of 0 or 45 degrees. Velocities were vertical 10 and horizontal 10, though two trials were simple vertical drops. [Entire movie available on DVD from CASI as Doc ID 20070030974. Contact help@sti.nasa.gov

  2. Biology Excursions

    ERIC Educational Resources Information Center

    Baldock, R. N.

    1973-01-01

    Provides many useful suggestions and cautions for planning and executing a biology field excursion. Specific procedures are outlined for investigating land communities and coastal areas, and a number of follow-up laboratory activities are described. The appendix provides an extensive bibliography with useful comments on the literature. (JR)

  3. Model-based control rescues boiler from steam-temperature excursions

    SciTech Connect

    Hanson, K.; Werre, J.; Chloupek, J.; Richerson, J.

    1995-05-01

    This article describes how, after operators of a lignite-fired boiler wrestled for years to control its main steam temperature, a switch to model-based control resolved the problem. Decoupling of control loops was essential. Montana Dakota Utilities (MDU) is the operator of the Coyote station, a 450-MW unit located at Beulah, ND, in the heart of lignite country. Owners of the plant are MDU, Northern Municipal Power Agency, Northwestern Public Service Co., and Otter Tail Power Co. The unit, a Babcock and Wilcox Co. (Barberton, Ohio) drum-boiler design, came on line in 1981. It burns lignite with a heating value of 6,900 Btu/lb using 12 cyclones. Because of unique boiler characteristics and controls implementation using several different control systems, the Coyote station had experienced significant steam-temperature excursions over the years.

  4. Statistical Model of Secular Variation and Excursions and Drilling to the Moho

    NASA Astrophysics Data System (ADS)

    Harrison, C. G.

    2007-12-01

    Almost all models for Earth's magnetic field secular variation derived from paleomagnetic results disregard results that give low latitude Virtual Geomagnetic Poles (VGPs). These results are regarded as "unusual" or "not part of the regular secular variation process". These low latitude VGPs are regarded as being produced at a time when the field is undergoing an excursion or a reversal and that therefore they should not be included in a secular variation study. However, it is almost impossible to determine logically the latitude of VGP below which results should be dismissed from study of the secular variation. And for some studies, it is important to include all results to arrive at a valid conclusion. This is the case with the paleomagnetic evidence that will be collected during the drilling through the oceanic crust to the Mohorovicic discontinuity, marking the top of the mantle. Accordingly, the results from the data set originally used by McElhinny and McFadden (1997) updated by addition of new results was expanded to include all the results giving low latitude VGPs that were left out of the updated data set. These expanded results were subjected to statistical analysis based on different latitude bands of the observation sites. This showed that for all latitude bands, the Fisher distribution gave a very bad fit to the data. However the data from every observational latitude band could be fitted by a Fisher distribution for about 90% of the data, plus a uniform distribution in latitude for the other 10% of the data. In addition, the Fisher distribution angular standard deviation showed a linear increase with observation latitude, rising from 11.5º at 10º latitude to 20º at 66º latitude. These results can be used to define a simple model which allows us to estimate the scatter to be found at any latitude, and in particular to determine the scatter in inclination that would be obtained from unoriented samples of basalt recovered during the Integrated Ocean

  5. Development of a Bayesian Belief Network Runway Incursion and Excursion Model

    NASA Technical Reports Server (NTRS)

    Green, Lawrence L.

    2014-01-01

    In a previous work, a statistical analysis of runway incursion (RI) event data was conducted to ascertain the relevance of this data to the top ten Technical Challenges (TC) of the National Aeronautics and Space Administration (NASA) Aviation Safety Program (AvSP). The study revealed connections to several of the AvSP top ten TC and identified numerous primary causes and contributing factors of RI events. The statistical analysis served as the basis for developing a system-level Bayesian Belief Network (BBN) model for RI events, also previously reported. Through literature searches and data analysis, this RI event network has now been extended to also model runway excursion (RE) events. These RI and RE event networks have been further modified and vetted by a Subject Matter Expert (SME) panel. The combined system-level BBN model will allow NASA to generically model the causes of RI and RE events and to assess the effectiveness of technology products being developed under NASA funding. These products are intended to reduce the frequency of runway safety incidents/accidents, and to improve runway safety in general. The development and structure of the BBN for both RI and RE events are documented in this paper.

  6. A Model for the Decrease in Amplitude of Carbon Isotope Excursions Throughout the Phanerozoic

    NASA Astrophysics Data System (ADS)

    Bachan, A.; Lau, K. V.; Saltzman, M.; Thomas, E.; Kump, L. R.; Payne, J.

    2016-12-01

    The geological cycling of carbon ties the ocean-­atmosphere carbon pool to Earth's biosphere and sedimentary reservoirs. Perturbations to this coupled system are recorded in the carbon-isotopic (δ13C) composition of marine carbonates. Large amplitude δ13C variations with durations of 0.5 - 10 m.y. are typically treated as individual events and interpreted accordingly. However, a recent compilation of Phanerozoic data reveals a decline in the variance of the δ13C record over time, suggesting a common underlying control. Here we propose that the redox structure of the continental shelves was a key determinant of the sensitivity of the geologic carbon cycle: when oxygen minimum zones (OMZs) were large, shallow, and prone to expansion, recurrent physical forcings (such as sea level and tectonics) would have had the capacity to drive large changes in the areal extent of OMZs, resulting in a strong leverage on δ13C values. Using a simple model of the geologic carbon cycle, we demonstrate that interactions between the carbon and phosphate cycles can result in amplification of recurrent forcings with periods in the 0.5 - 10 m.y. range. Thus, rather than requiring that physical forcings have their largest amplitude of variation on those time scales, enhanced sensitivity of the carbon cycle can account for the characteristic duration of δ13C excursions. Biologically mediated aspects of geologic carbon cycling, including the depth of bioturbation and evolution of pelagic calcifiers, likely drove a decline in the depth and extent of ocean anoxia over the Phanerozoic resulting in the stabilization of the geologic carbon cycle.

  7. Flow excursion time scales in the advanced neutron source reactor

    SciTech Connect

    Sulfredge, C.D.

    1995-04-01

    Flow excursion transients give rise to a key thermal limit for the proposed Advanced Neutron Source (ANS) reactor because its core involves many parallel flow channels with a common pressure drop. Since one can envision certain accident scenarios in which the thermal limits set by flow excursion correlations might be exceeded for brief intervals, a key objective is to determine how long a flow excursion would take to bring about a system failure that could lead to fuel damage. The anticipated time scale for flow excursions has been examined by subdividing the process into its component phenomena: bubble nucleation and growth, deceleration of the resulting two-phase flow, and finally overcoming thermal inertia to heat up the reactor fuel plates. Models were developed to estimate the time required for each individual stage. Accident scenarios involving sudden reduction in core flow or core exit pressure have been examined, and the models compared with RELAP5 output for the ANS geometry. For a high-performance reactor like the ANS, flow excursion time scales were predicted to be in the millisecond range, so that even very brief transients might lead to fuel damage. These results should prove useful whenever one must determine the time involved in any portion of a flow excursion transient.

  8. Record of the Late Devonian Hangenberg global positive carbon-isotope excursion in an epeiric sea setting: Carbonate production, organic-carbon burial and paleoceanography during the late Famennian

    USGS Publications Warehouse

    Cramer, Bradley D.; Saltzman, Matthew R.; Day, J.E.; Witzke, B.J.

    2008-01-01

    Latest Famennian marine carbonates from the mid-continent of North America were examined to investigate the Late Devonian (very late Famennian) Hangenberg positive carbon-isotope (??13 Ccarb) excursion. This global shift in the ?? 13C of marine waters began during the late Famennian Hangenberg Extinction Event that occurred during the Middle Siphonodella praesulcata conodont zone. The post-extinction recovery interval spans the Upper S. praesulcata Zone immediately below the Devonian-Carboniferous boundary. Positive excursions in ?? 13 Ccarb are often attributed to the widespread deposition of organic-rich black shales in epeiric sea settings. The Hangenberg ??13 Ccarb excursion documented in the Louisiana Limestone in this study shows the opposite trend, with peak ??13 Ccarb values corresponding to carbonate production in the U.S. mid-continent during the highstand phase of the very late Famennian post-glacial sea level rise. Our data indicate that the interval of widespread black shale deposition (Hangenberg Black Shale) predates the peak isotope values of the Hangenberg ??13 Ccarb excursion and that peak values of the Hangenberg excursion in Missouri are not coincident with and cannot be accounted for by high Corg burial in epeiric seas. We suggest instead that sequestration and burial of Corg in the deep oceans drove the peak interval of the ??13Ccarb excursion, as a result of a change in the site of deep water formation to low-latitude epeiric seas as the global climate shifted between cold and warm states.

  9. Isokinetic eccentric exercise can induce skeletal muscle injury within the physiologic excursion of muscle-tendon unit: a rabbit model

    PubMed Central

    Tsuang, Yang-Hwei; Lam, Shui-Ling; Wu, Lien-Chen; Chiang, Chang-Jung; Chen, Li-Ting; Chen, Pei-Yu; Sun, Jui-Sheng; Wang, Chien-Che

    2007-01-01

    Background and Purpose Intensive eccentric exercise can cause muscle damage. We simulated an animal model of isokinetic eccentric exercise by repetitively stretching stimulated triceps surae muscle-tendon units to determine if such exercise affects the mechanical properties of the unit within its physiologic excursion. Methods Biomechanical parameters of the muscle-tendon unit were monitored during isokinetic eccentric loading in 12 rabbits. In each animal, one limb (control group) was stretched until failure. The other limb (study group) was first subjected to isokinetic and eccentric cyclic loading at the rate of 10.0 cm/min to 112% (group I) or 120% (group II) of its initial length for 1 hour and then stretched to failure. Load-deformation curves and biomechanical parameters were compared between the study and control groups. Results When the muscle-tendon unit received eccentric cyclic loading to 112%, changes in all biomechanical parameters – except for the slope of the load-deformation curve – were not significant. In contrast, most parameters, including the slope of the load-deformation curve, peak load, deformation at peak load, total energy absorption, and energy absorption before peak load, significantly decreased after isokinetic eccentric cyclic loading to 120%. Conclusion We found a threshold for eccentrically induced injury of the rabbit triceps surae muscle at between 12% and 20% strain, which is within the physiologic excursion of the muscle-tendon units. Our study provided evidence that eccentric exercise may induce changes in the biomechanical properties of skeletal muscles, even within the physiologic range of the excursion of the muscle-tendon unit. PMID:17711591

  10. Economic communication model set

    NASA Astrophysics Data System (ADS)

    Zvereva, Olga M.; Berg, Dmitry B.

    2017-06-01

    This paper details findings from the research work targeted at economic communications investigation with agent-based models usage. The agent-based model set was engineered to simulate economic communications. Money in the form of internal and external currencies was introduced into the models to support exchanges in communications. Every model, being based on the general concept, has its own peculiarities in algorithm and input data set since it was engineered to solve the specific problem. Several and different origin data sets were used in experiments: theoretic sets were estimated on the basis of static Leontief's equilibrium equation and the real set was constructed on the basis of statistical data. While simulation experiments, communication process was observed in dynamics, and system macroparameters were estimated. This research approved that combination of an agent-based and mathematical model can cause a synergetic effect.

  11. Design of a full scale model fuel assembly for full power production reactor flow excursion experiments

    SciTech Connect

    Nash, C.A. ); Blake, J.E.; Rush, G.C. )

    1990-01-01

    A novel full scale production reactor fuel assembly model was designed and built to study thermal-hydraulic effects of postulated Savannah River Site (SRS) nuclear reactor accidents. The electrically heated model was constructed to simulate the unique annular concentric tube geometry of fuel assemblies in SRS nuclear production reactors. Several major design challenges were overcome in order to produce the prototypic geometry and thermal-hydraulic conditions. The two concentric heater tubes (total power over 6 MW and maximum heat flux of 3.5 MW/m{sup 2}) (1.1E+6 BTU/(ft{sup 2}hr)) were designed to closely simulate the thermal characteristics of SRS uranium-aluminum nuclear fuel. The paper discusses the design of the model fuel assembly, which met requirements of maintaining prototypic geometric and hydraulic characteristics, and approximate thermal similarity. The model had a cosine axial power profile and the electrical resistance was compatible with the existing power supply. The model fuel assembly was equipped with a set of instruments useful for code analysis, and durable enough to survive a number of LOCA transients. These instruments were sufficiently responsive to record the response of the fuel assembly to the imposed transient.

  12. Design of a full scale model fuel assembly for full power production reactor flow excursion experiments

    SciTech Connect

    Nash, C.A.; Blake, J.E.; Rush, G.C.

    1990-12-31

    A novel full scale production reactor fuel assembly model was designed and built to study thermal-hydraulic effects of postulated Savannah River Site (SRS) nuclear reactor accidents. The electrically heated model was constructed to simulate the unique annular concentric tube geometry of fuel assemblies in SRS nuclear production reactors. Several major design challenges were overcome in order to produce the prototypic geometry and thermal-hydraulic conditions. The two concentric heater tubes (total power over 6 MW and maximum heat flux of 3.5 MW/m{sup 2}) (1.1E+6 BTU/(ft{sup 2}hr)) were designed to closely simulate the thermal characteristics of SRS uranium-aluminum nuclear fuel. The paper discusses the design of the model fuel assembly, which met requirements of maintaining prototypic geometric and hydraulic characteristics, and approximate thermal similarity. The model had a cosine axial power profile and the electrical resistance was compatible with the existing power supply. The model fuel assembly was equipped with a set of instruments useful for code analysis, and durable enough to survive a number of LOCA transients. These instruments were sufficiently responsive to record the response of the fuel assembly to the imposed transient.

  13. Preliminary Landing Tests of a 1/6-Scale Dynamic Model of a Lunar Excursion Vehicle

    NASA Technical Reports Server (NTRS)

    1962-01-01

    The film shows 21 trials made on 8 days of the scale Model 413 lunar landing vehicle. Attitudes tested were a pitch of 0, -15, or 15 degrees and yaw of 0 or 45 degrees. Velocities were vertical 10 and horizontal 10, though two trials were simple vertical drops.

  14. A diagenetic control on the Early Triassic Smithian-Spathian carbon isotopic excursions recorded in the marine settings of the Thaynes Group (Utah, USA).

    PubMed

    Thomazo, C; Vennin, E; Brayard, A; Bour, I; Mathieu, O; Elmeknassi, S; Olivier, N; Escarguel, G; Bylund, K G; Jenks, J; Stephen, D A; Fara, E

    2016-05-01

    In the aftermath of the end-Permian mass extinction, Early Triassic sediments record some of the largest Phanerozoic carbon isotopic excursions. Among them, a global Smithian-negative carbonate carbon isotope excursion has been identified, followed by an abrupt increase across the Smithian-Spathian boundary (SSB; ~250.8 Myr ago). This chemostratigraphic evolution is associated with palaeontological evidence that indicate a major collapse of terrestrial and marine ecosystems during the Late Smithian. It is commonly assumed that Smithian and Spathian isotopic variations are intimately linked to major perturbations in the exogenic carbon reservoir. We present paired carbon isotopes measurements from the Thaynes Group (Utah, USA) to evaluate the extent to which the Early Triassic isotopic perturbations reflect changes in the exogenic carbon cycle. The δ(13) Ccarb variations obtained here reproduce the known Smithian δ(13) Ccarb -negative excursion. However, the δ(13) C signal of the bulk organic matter is invariant across the SSB and variations in the δ(34) S signal of sedimentary sulphides are interpreted here to reflect the intensity of sediment remobilization. We argue that Middle to Late Smithian δ(13) Ccarb signal in the shallow marine environments of the Thaynes Group does not reflect secular evolution of the exogenic carbon cycle but rather physicochemical conditions at the sediment-water interface leading to authigenic carbonate formation during early diagenetic processes. © 2016 John Wiley & Sons Ltd.

  15. Bounded excursion stable gravastars and black holes

    SciTech Connect

    Rocha, P; Da Silva, M F; Wang, Anzhong; Santos, N O E-mail: yasuda@on.br E-mail: mfasnic@gmail.com E-mail: anzhong_wang@baylor.edu

    2008-06-15

    Dynamical models of prototype gravastars were constructed in order to study their stability. The models are the Visser-Wiltshire three-layer gravastars, in which an infinitely thin spherical shell of stiff fluid divides the whole spacetime into two regions, where the internal region is de Sitter, and the external one is Schwarzschild. It is found that in some cases the models represent the 'bounded excursion' stable gravastars, where the thin shell is oscillating between two finite radii, while in other cases they collapse until the formation of black holes occurs. In the phase space, the region for the 'bounded excursion' gravastars is very small in comparison to that of black holes, but not empty. Therefore, although the possibility of the existence of gravastars cannot be excluded from such dynamical models, our results indicate that, even if gravastars do indeed exist, that does not exclude the possibility of the existence of black holes.

  16. Complete Basis Set Model Chemistries

    NASA Astrophysics Data System (ADS)

    Ochterski, Joseph Wallace

    1994-01-01

    The major source of error in most ab initio calculations of molecular energies is the truncation of the one-electron basis set. Extrapolation to the complete basis set second -order (CBS2) limit using the N^{-1 } asymptotic convergence of N-configuration pair natural orbital (PNO) expansions can be combined with the use of relatively small basis sets for the higher-order correlation energy to develop cost effective computational models. Following this strategy, four new computational models denoted CBS-4, CBS-q, CBS-Q, and CBS-QCI/APNO are introduced. The mean absolute deviations (MAD) from experiment for the 125 energies of the G2 test set are 2.0, 1.7, 1.0 and 0.5 kcal/mol, respectively. The error distributions for all six models are indistinguishable from Gaussian distribution functions. Calculations on the cyclopropenyl radical and cyclopropenylidene provide new dissociation energies which are in accord with an interpretation of the thermochemistry emphasizing aromaticity. Several levels of theory are examined as candidates for the routine calculation of molecular geometries. The very simple UHF/3-21G* model gives bond lengths to an accuracy of +/-0.027 A compared with experiment for a test set of 69 small molecules. The commonly used MP2/6-31G* model (RMS error 0.025 A) offers virtually no improvement and use of the considerably more expensive QCISD calculations with the same basis set provides only a modest reduction to 0.020 A. However, spin projected MP3 calculations with a modified basis set including f -functions on Si, P, S, and Cl, reduce the RMS error to 0.010 A. This PMP3/6-31Gdf* model is recommended as a general scheme of geometry optimization for small molecules. The equilibrium structure and binding energy of the water dimer have been determined for several levels of ab initio theory. The basis set convergence of the SCF energy, the intramolecular and intermolecular MP2 energy, and higher-order effects, are examined separately and realistic error

  17. Compliant bipedal model with the center of pressure excursion associated with oscillatory behavior of the center of mass reproduces the human gait dynamics.

    PubMed

    Jung, Chang Keun; Park, Sukyung

    2014-01-03

    Although the compliant bipedal model could reproduce qualitative ground reaction force (GRF) of human walking, the model with a fixed pivot showed overestimations in stance leg rotation and the ratio of horizontal to vertical GRF. The human walking data showed a continuous forward progression of the center of pressure (CoP) during the stance phase and the suspension of the CoP near the forefoot before the onset of step transition. To better describe human gait dynamics with a minimal expense of model complexity, we proposed a compliant bipedal model with the accelerated pivot which associated the CoP excursion with the oscillatory behavior of the center of mass (CoM) with the existing simulation parameter and leg stiffness. Owing to the pivot acceleration defined to emulate human CoP profile, the arrival of the CoP at the limit of the stance foot over the single stance duration initiated the step-to-step transition. The proposed model showed an improved match of walking data. As the forward motion of CoM during single stance was partly accounted by forward pivot translation, the previously overestimated rotation of the stance leg was reduced and the corresponding horizontal GRF became closer to human data. The walking solutions of the model ranged over higher speed ranges (~1.7 m/s) than those of the fixed pivoted compliant bipedal model (~1.5m/s) and exhibited other gait parameters, such as touchdown angle, step length and step frequency, comparable to the experimental observations. The good matches between the model and experimental GRF data imply that the continuous pivot acceleration associated with CoM oscillatory behavior could serve as a useful framework of bipedal model.

  18. Dynamics of the Laschamp geomagnetic excursion from Black Sea sediments

    NASA Astrophysics Data System (ADS)

    Nowaczyk, N. R.; Arz, H. W.; Frank, U.; Kind, J.; Plessen, B.

    2012-10-01

    Investigated sediment cores from the southeastern Black Sea provide a high-resolution record from mid latitudes of the Laschamp geomagnetic polarity excursion. Age constraints are provided by 16 AMS 14C ages, identification of the Campanian Ignimbrite tephra (39.28±0.11 ka), and by detailed tuning of sedimentologic parameters of the Black Sea sediments to the oxygen isotope record from the Greenland NGRIP ice core. According to the derived age model, virtual geomagnetic pole (VGP) positions during the Laschamp excursion persisted in Antarctica for an estimated 440 yr, making the Laschamp excursion a short-lived event with fully reversed polarity directions. The reversed phase, centred at 41.0 ka, is associated with a significant field intensity recovery to 20% of the preceding strong field maximum at ˜50 ka. Recorded field reversals of the Laschamp excursion, lasting only an estimated ˜250 yr, are characterized by low relative paleointensities (5% relative to 50 ka). The central, fully reversed phase of the Laschamp excursion is bracketed by VGP excursions to the Sargasso Sea (˜41.9 ka) and to the Labrador Sea (˜39.6 ka). Paleomagnetic results from the Black Sea are in excellent agreement with VGP data from the French type locality which facilitates the chronological ordering of the non-superposed lavas that crop out at Laschamp-Olby. In addition, VGPs between 34 and 35 ka reach low northerly to equatorial latitudes during a clockwise loop, inferred to be the Mono lake excursion.

  19. Analysis of the Effect of Historical Cultural Changes Relative to the Development of Affordability Excursions to Existing Parametric Cost Models

    DTIC Science & Technology

    1988-09-30

    August 1985. "V-22 Osprey Tit-Rotor Rollout Date Set." Headline 88-18 (May 11, 1988): 1. Van Riper , Paul P. History of the United States Civil Service...earlier Ballista, the Catapult, and the Trebuchet. Charles VIII of France-interested in territorial expansion into Italy-launched his Italian -A campaign...scientists as Bacon, Copernicus, Kepler, Galileo, Descarte.z, Newton and others. These rationalists rescued humanity from the disorder of chance by

  20. Unphysical scalar excursions in large-eddy simulations

    NASA Astrophysics Data System (ADS)

    Matheou, Georgios; Dimotakis, Paul

    2016-11-01

    The range of physically realizable values of passive scalar fields in any flow is bounded by their boundary values. The current investigation focuses on the local conservation of passive scalar concentration fields in turbulent flows and the ability of the large-eddy simulation (LES) method to observe the boundedness of passive scalar concentrations. In practice, as a result of numerical artifacts, this fundamental constraint is often violated with scalars exhibiting unphysical excursions. The present study characterizes passive-scalar excursions in LES of a turbulent shear flow and examines methods for error diagnosis. Typically, scalar-excursion errors are diagnosed as violations of global boundedness, i.e., detecting scalar-concentration values outside boundary/initial condition bounds. To quantify errors in mixed-fluid regions, a local scalar excursion error metric is defined with respect to the local non-diffusive limit. Analysis of such errors shows that unphysical scalar excursions in LES result from dispersive errors of the convection-term discretization where the subgrid-scale model (SGS) provides insufficient dissipation to produce a sufficiently smooth scalar field. Local scalar excursion errors are found not to be correlated with the local scalar-gradient magnitude. This work is supported by AFOSR, DOE, and Caltech.

  1. Excursions in technology policy

    NASA Technical Reports Server (NTRS)

    Archibald, Robert B.

    1995-01-01

    This technical report presents a summary of three distinct projects: (1) Measuring economic benefits; (2) Evaluating the SBIR program; and (3) A model for evaluating changes in support for science and technology. the first project deals with the Technology Applications Group (TAG) at NASA Langley Research Center. The mission of TAG is to assist firms interested in commercializing technologies. TAG is a relatively new group as is the emphasis on technology commercialization for NASA. One problem faced by TAG and similar groups at other centers is measuring their effectiveness. The first project this summer, a paper entitled, 'Measuring the Economic Benefits of Technology Transfer from a National Laboratory: A Primer,' focused on this measurement problem. We found that the existing studies of the impact of technology transfer on the economy were conceptually flawed. The 'primer' outlines the appropriate theoretical framework for measuring the economic benefits of technology transfer. The second project discusses, one of the programs of TAG, the Small Business Innovation Research (SBIR) program. This program has led to over 400 contracts with Small Business since its inception in 1985. The program has never been evaluated. Crucial questions such as those about the extent of commercial successes from the contracts need to be answered. This summer we designed and implemented a performance evaluation survey instrument. The analysis of the data will take place in the fall. The discussion of the third project focuses on a model for evaluating changes in support for science and technology. At present several powerful forces are combining to change the environment for science and technology policy. The end of the cold war eliminated the rationale for federal support for many projects. The new- found Congressional conviction to balance the budget without tax increases combined with demographic changes which automatically increase spending for some politically popular programs

  2. Excursions in technology policy

    NASA Technical Reports Server (NTRS)

    Archibald, Robert B.

    1995-01-01

    This technical report presents a summary of three distinct projects: (1) Measuring economic benefits; (2) Evaluating the SBIR program; and (3) A model for evaluating changes in support for science and technology. the first project deals with the Technology Applications Group (TAG) at NASA Langley Research Center. The mission of TAG is to assist firms interested in commercializing technologies. TAG is a relatively new group as is the emphasis on technology commercialization for NASA. One problem faced by TAG and similar groups at other centers is measuring their effectiveness. The first project this summer, a paper entitled, 'Measuring the Economic Benefits of Technology Transfer from a National Laboratory: A Primer,' focused on this measurement problem. We found that the existing studies of the impact of technology transfer on the economy were conceptually flawed. The 'primer' outlines the appropriate theoretical framework for measuring the economic benefits of technology transfer. The second project discusses, one of the programs of TAG, the Small Business Innovation Research (SBIR) program. This program has led to over 400 contracts with Small Business since its inception in 1985. The program has never been evaluated. Crucial questions such as those about the extent of commercial successes from the contracts need to be answered. This summer we designed and implemented a performance evaluation survey instrument. The analysis of the data will take place in the fall. The discussion of the third project focuses on a model for evaluating changes in support for science and technology. At present several powerful forces are combining to change the environment for science and technology policy. The end of the cold war eliminated the rationale for federal support for many projects. The new- found Congressional conviction to balance the budget without tax increases combined with demographic changes which automatically increase spending for some politically popular programs

  3. Age and duration of Laschamp and Iceland Basin geomagnetic excursions in the South Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Channell, J. E. T.; Vázquez Riveiros, N.; Gottschalk, J.; Waelbroeck, C.; Skinner, L. C.

    2017-07-01

    Age models for new records of the Laschamp and Iceland Basin excursions from the eastern flank of the South Atlantic mid-ocean ridge (44.15°S, 14.22°W) are derived from radiocarbon dates, and from matching sea-surface temperature records to Antarctic (EPICA) air-temperature records from ice cores. The onset of the Laschamp excursion occurred during Antarctic Isotopic Maximum (AIM) 10, consistent with its occurrence during Greenland Interstadial 10. The end of the Laschamp excursion occurred prior to AIM 9 in Greenland Stadial 10. The age model is supported by synchroneity of directional and relative paleointensity manifestations of the Laschamp excursion in the marine core with peaks in EPICA10Be and nitrate flux. The Iceland Basin excursion is synchronous with the final phase of the transition from marine isotope stage (MIS) 7a to MIS 6e as recorded in the EPICA δD record. The onset of the Laschamp and Iceland Basin excursions, defined here by component inclinations >-40°, occurred at 41.4 ka and 190.0 ka, and durations are ∼1 kyr and ∼3.5 kyr, respectively, although these estimates depend on the criteria used to define the directional excursions. By comparison with Laschamp and Iceland Basin excursion records from the North Atlantic Ocean, the two excursions are synchronous at centennial timescales between the two hemispheres, based on synchronization of the GICC05 and AICC2012 age models for Greenland and Antarctic ice cores.

  4. Excursion detection using leveling data

    NASA Astrophysics Data System (ADS)

    Kim, MinGyu; Ju, Jaewuk; Habets, Boris; Erley, Georg; Bellmann, Enrico; Kim, Seop

    2016-03-01

    Wafer leveling data are usually used inside the exposure tool for ensuring good focus, then discarded. This paper describes the implementation of a monitoring and analysis solution to download these data automatically, together with the correction profiles applied by the scanner. The resulting height maps and focus residuals form the basis for monitoring metrics tailored to catching tool and process drifts and excursions in a high-volume manufacturing (HVM) environment. In this paper, we present four six cases to highlight the potential of the method: wafer edge monitoring, chuck drift monitoring, correlations between focus residuals and overlay errors, and pre-process monitoring by chuck fingerprint removal.

  5. Buoyancy-driven flow excursions in fuel assemblies

    SciTech Connect

    Laurinat, J.E.; Paul, P.K.; Menna, J.D.

    1995-09-01

    A power limit criterion was developed for a postulated Loss of Pumping Accident (LOPA) in one of the recently shut down heavy water production reactors at the Savannah River Site. These reactors were cooled by recirculating heavy water moderator downward through channels in cylindrical fuel tubes. Powers were limited to safeguard against a flow excursion in one of more of these parallel channels. During-full-power operation, limits safeguarded against a boiling flow excursion. At low flow rates, during the addition of emergency cooling water, buoyant forces reverse the flow in one of the coolant channels before boiling occurs. As power increased beyond the point of flow reversal, the maximum wall temperature approaches the fluid saturation temperature, and a thermal excursion occurs. The power limit criterion for low flow rates was the onset of flow reversal. To determine conditions for flow reversal, tests were performed in a mock-up of a fuel assembly that contained two electrically heated concentric tubes surrounded by three flow channels. These tests were modeled using a finite difference thermal-hydraulic code. According to code calculations, flow reversed in the outer flow channel before the maximum wall temperature reached the local fluid saturation temperature. Thermal excursions occurred when the maximum wall temperature approximately equaled the saturation temperature. For a postulated LOPA, the flow reversal criterion for emergency cooling water addition was more limiting than the boiling excursion criterion for full power operation. This criterion limited powers to 37% of the limiting power for previous long-term reactor operations.

  6. Buoyancy-driven flow excursions in fuel assemblies

    SciTech Connect

    Laurinat, J.E.; Paul, P.K.; Menna, J.D.

    1995-12-31

    A power limit criterion was developed for a postulated Loss of Pumping Accident (LOPA) in one of the recently shut down heavy water production reactors at the Savannah River Site. These reactors were cooled by recirculating moderator downward through channels in cylindrical fuel tubes. Powers were limited to prevent a flow excursion from occurring in one or more of these parallel channels. During full-power operation, limits prevented a boiling flow excursion from taking place. At low flow rates, during the addition of emergency cooling water, buoyant forces reverse the flow in one of the coolant channels before boiling occurs. As power increases beyond the point of flow reversal, the maximum wall temperature approaches the fluid saturation temperature, and a thermal excursion occurs. The power limit criterion for low flow rates was the onset of flow reversal. To determine conditions for flow reversal, tests were performed in a mock-up of a fuel assembly that contained two electrically heated concentric tubes surrounded by three flow channels. These tests were modeled using a finite difference thermal-hydraulic code. According to code calculations, flow reversed in the outer flow channel before the maximum wall temperature reached the local fluid saturation temperature. Thermal excursions occurred when the maximum wall temperature approximately equaled the saturation temperature. For a postulated LOPA, the flow reversal criterion for emergency cooling water addition was more limiting than the boiling excursion criterion for full power operation. This criterion limited powers to 37% of historical levels.

  7. An investigation of the dynamic relationship between navicular drop and first metatarsophalangeal joint dorsal excursion.

    PubMed

    Griffin, Nicole L; Miller, Charlotte; Schmitt, Daniel; D'Août, Kristiaan

    2013-06-01

    The modern human foot is a complex biomechanical structure that must act both as a shock absorber and as a propulsive strut during the stance phase of gait. Understanding the ways in which foot segments interact can illuminate the mechanics of foot function in healthy and pathological humans. It has been proposed that increased values of medial longitudinal arch deformation can limit metatarsophalangeal joint excursion via tension in the plantar aponeurosis. However, this model has not been tested directly in a dynamic setting. In this study, we tested the hypothesis that during the stance phase, subtalar pronation (stretching of the plantar aponeurosis and subsequent lowering of the medial longitudinal arch) will negatively affect the amount of first metatarsophalangeal joint excursion occurring at push-off. Vertical descent of the navicular (a proxy for subtalar pronation) and first metatarsophalangeal joint dorsal excursion were measured during steady locomotion over a flat substrate on a novel sample consisting of asymptomatic adult males and females, many of whom are habitually unshod. Least-squares regression analyses indicated that, contrary to the hypothesis, navicular drop did not explain a significant amount of variation in first metatarsophalangeal joint dorsal excursion. These results suggest that, in an asymptomatic subject, the plantar aponeurosis and the associated foot bones can function effectively within the normal range of subtalar pronation that takes place during walking gait. From a clinical standpoint, this study highlights the need for investigating the in vivo kinematic relationship between subtalar pronation and metatarsophalangeal joint dorsiflexion in symptomatic populations, and also the need to explore other factors that may affect the kinematics of asymptomatic feet.

  8. An investigation of the dynamic relationship between navicular drop and first metatarsophalangeal joint dorsal excursion

    PubMed Central

    Griffin, Nicole L; Miller, Charlotte; Schmitt, Daniel; D'Août, Kristiaan

    2013-01-01

    The modern human foot is a complex biomechanical structure that must act both as a shock absorber and as a propulsive strut during the stance phase of gait. Understanding the ways in which foot segments interact can illuminate the mechanics of foot function in healthy and pathological humans. It has been proposed that increased values of medial longitudinal arch deformation can limit metatarsophalangeal joint excursion via tension in the plantar aponeurosis. However, this model has not been tested directly in a dynamic setting. In this study, we tested the hypothesis that during the stance phase, subtalar pronation (stretching of the plantar aponeurosis and subsequent lowering of the medial longitudinal arch) will negatively affect the amount of first metatarsophalangeal joint excursion occurring at push-off. Vertical descent of the navicular (a proxy for subtalar pronation) and first metatarsophalangeal joint dorsal excursion were measured during steady locomotion over a flat substrate on a novel sample consisting of asymptomatic adult males and females, many of whom are habitually unshod. Least-squares regression analyses indicated that, contrary to the hypothesis, navicular drop did not explain a significant amount of variation in first metatarsophalangeal joint dorsal excursion. These results suggest that, in an asymptomatic subject, the plantar aponeurosis and the associated foot bones can function effectively within the normal range of subtalar pronation that takes place during walking gait. From a clinical standpoint, this study highlights the need for investigating the in vivo kinematic relationship between subtalar pronation and metatarsophalangeal joint dorsiflexion in symptomatic populations, and also the need to explore other factors that may affect the kinematics of asymptomatic feet. PMID:23600634

  9. Framing Learning Conditions in Geography Excursions

    ERIC Educational Resources Information Center

    Jonasson, Mikael

    2011-01-01

    The aim of this paper is to investigate and frame some learning conditions involved in the practice of geographical excursions. The empirical material from this study comes from several excursions made by students in human geography and an ethnomethodological approach through participant observation is used. The study is informed by theories from…

  10. Rough set models of Physarum machines

    NASA Astrophysics Data System (ADS)

    Pancerz, Krzysztof; Schumann, Andrew

    2015-04-01

    In this paper, we consider transition system models of behaviour of Physarum machines in terms of rough set theory. A Physarum machine, a biological computing device implemented in the plasmodium of Physarum polycephalum (true slime mould), is a natural transition system. In the behaviour of Physarum machines, one can notice some ambiguity in Physarum motions that influences exact anticipation of states of machines in time. To model this ambiguity, we propose to use rough set models created over transition systems. Rough sets are an appropriate tool to deal with rough (ambiguous, imprecise) concepts in the universe of discourse.

  11. Does the Shuram δ13C excursion record Ediacaran oxygenation?

    NASA Astrophysics Data System (ADS)

    Husson, J. M.; Maloof, A. C.; Schoene, B.; Higgins, J. A.

    2013-12-01

    The most negative carbon isotope excursion in Earth history is found in carbonate rocks of the Ediacaran Period (635-542 Ma). Known colloquially as the the 'Shuram' excursion, workers have long noted its tantalizing, broad concordance with the rise of abundant macro-scale fossils in the rock record, variously interpreted as animals, giant protists, macro-algae and lichen, and known as the 'Ediacaran Biota.' Thus, the Shuram excursion has been interpreted by many in the context of a dramatically changing redox state of the Ediacaran oceans - e.g., a result of methane cycling in a low O2 atmosphere, the final destruction of a large pool of recalcitrant dissolved organic carbon (DOC), and the step-wise oxidation of the Ediacaran oceans. More recently, diagenetic interpretations of the Shuram excursion - e.g. sedimentary in-growth of very δ13C depleted authigenic carbonates, meteoric alteration of Ediacaran carbonates, late-stage burial diagenesis - have challenged the various Ediacaran redox models. A rigorous geologic context is required to discriminate between these explanatory models, and determine whether the Shuram excursion can be used to evaluate terminal Neoproterozoic oxygenation. Here, we present chemo-stratigraphic data (δ13C, δ18O, δ44/42Ca and redox sensitive trace element abundances) from 12 measured sections of the Ediacaran-aged Wonoka Formation (Fm.) of South Australia that require a syn-depositional age for the extraordinary range of δ13C values (-12 to +4‰) observed in the formation. In some locations, the Wonoka Fm. is ~700 meters (m) of mixed shelf limestones and siliclastics that record the full 16 ‰ δ13C excursion in a remarkably consistent fashion across 100s of square kilometers of basin area. Fabric-altering diagenesis, where present, occurs at the sub-meter vertical scale, only results in sub-permil offsets in δ13C and cannot be used to explain the full δ13C excursion. In other places, the Wonoka Fm. is host to deep (1 km

  12. Autonomous excursions using tablets and smartphones

    NASA Astrophysics Data System (ADS)

    Marra, Wouter; Groothengel, Marin; van de Grint, Liesbeth; Karssenberg, Derek; Stouthamer, Esther

    2017-04-01

    Excursions and fieldworks are valuable components for geosciences education. However, field activities can be time consuming for teachers and pose a logistical challenge to fit in regular courses. Furthermore, the participation of students diminishes with group size in case of instructor-led outings. We are developing excursions that students can follow autonomously without a teacher present, using instructions, assignments and background information on tablets and smartphones. The goal of this approach is to increase the level of active participation, and to reduce logistical and time table issues. We developed a bike-excursion about the landscape and geology in the vicinity of our University. Such excursion was on the wish-list for several years, but posed a logistical challenge for the group of about 80 students in the available timeslot. In our approach, students had a time-window of two weeks in which they could finish the excursion in groups of 2. 8-Inch tablets with water- and shock-proof cases were available for this excursion. For the excursion we used three apps: 1) IZI-Travel for providing the route, spoken navigation instructions, spoken explanations at stops, location-related images, assignments as text, and multiple-choose questions. 2) PDF-Maps for providing geo-referenced maps. 3) ESRI Collector which the students used to digitize polygons on a map, and to collect geo-referenced photos with explanation. These data were answers to assignments and were later used in a tutorial on campus. The assignments where students had to collect data, and the small group size (pairs) increased the level of active participation. The use of a final tutorial on campus was important for the autonomous excursion, as it gave students the opportunity to discuss their observations and questions with their teacher. The developed teaching materials are available online to use and adapt for others. Parts could be useful for other universities and schools in the vicinity of

  13. Simulation of Altered Excursion of the Pronator Quadratus

    PubMed Central

    Feeney, Micheal S.; Wentorf, Fred; Putnam, Matthew D.

    2014-01-01

    Background Loss of forearm rotation is frequently seen after healing of distal radius fractures. Questions/Purposes Our purpose was to determine whether restricted excursion of the pronator quadratus muscle can affect forearm rotation. Methods We evaluated the relationship between pronator quadratus excursion and forearm rotation in a cadaveric model. Eight adult fresh-frozen above-elbow specimens were attached to a mounting device that permitted free rotation of the forearm around its ulnar axis. Forearm rotation was measured with a protractor while alternating pronation and supination loads were applied. Measurements were repeated after restricting the excursion of pronator quadratus by 10, 20, and 30% of its initial length. Results There was a mean 15° loss of supination for each 10% reduction in pronator excursion. There was no significant effect on pronation. Conclusions We conclude that, independent of any bone deformity or nearby joint stiffness, posttraumatic scarring of this muscle may result in a loss of supination. PMID:25097814

  14. Human risk factors associated with pilots in runway excursions.

    PubMed

    Chang, Yu-Hern; Yang, Hui-Hua; Hsiao, Yu-Jung

    2016-09-01

    A breakdown analysis of civil aviation accidents worldwide indicates that the occurrence of runway excursions represents the largest portion among all aviation occurrence categories. This study examines the human risk factors associated with pilots in runway excursions, by applying a SHELLO model to categorize the human risk factors and to evaluate the importance based on the opinions of 145 airline pilots. This study integrates aviation management level expert opinions on relative weighting and improvement-achievability in order to develop four kinds of priority risk management strategies for airline pilots to reduce runway excursions. The empirical study based on experts' evaluation suggests that the most important dimension is the liveware/pilot's core ability. From the perspective of front-line pilots, the most important risk factors are the environment, wet/containment runways, and weather issues like rain/thunderstorms. Finally, this study develops practical strategies for helping management authorities to improve major operational and managerial weaknesses so as to reduce the human risks related to runway excursions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Convex set and linear mixing model

    NASA Technical Reports Server (NTRS)

    Xu, P.; Greeley, R.

    1993-01-01

    A major goal of optical remote sensing is to determine surface compositions of the earth and other planetary objects. For assessment of composition, single pixels in multi-spectral images usually record a mixture of the signals from various materials within the corresponding surface area. In this report, we introduce a closed and bounded convex set as a mathematical model for linear mixing. This model has a clear geometric implication because the closed and bounded convex set is a natural generalization of a triangle in n-space. The endmembers are extreme points of the convex set. Every point in the convex closure of the endmembers is a linear mixture of those endmembers, which is exactly how linear mixing is defined. With this model, some general criteria for selecting endmembers could be described. This model can lead to a better understanding of linear mixing models.

  16. The Asymmetric Exclusion Process and Brownian Excursions

    NASA Astrophysics Data System (ADS)

    Derrida, B.; Enaud, C.; Lebowitz, J. L.

    2004-04-01

    We consider the totally asymmetric exclusion process (TASEP) in one dimension in its maximal current phase. We show, by an exact calculation, that the non-Gaussian part of the fluctuations of density can be described in terms of the statistical properties of a Brownian excursion. Numerical simulations indicate that the description in terms of a Brownian excursion remains valid for more general one dimensional driven systems in their maximal current phase.

  17. Geomagnetic excursions reflect an aborted polarity state

    NASA Astrophysics Data System (ADS)

    Valet, Jean-Pierre; Plenier, Guillaume; Herrero-Bervera, E.

    2008-10-01

    Geomagnetic excursions represent short episodes of a few thousand years at most during which the field considerably exceeds its normal range of variability during a polarity state. Paleomagnetic records have now been obtained with extremely high temporal resolution which have improved our knowledge of these short events. We have compiled the most detailed records of excursions that had occurred during the Brunhes and Matuyama chrons. We show that virtual geomagnetic poles (VGPs) of at least one record of each event are able to reach the opposite polarity. In the next step, we have computed different simulations of excursions during which the dipole progressively vanishes before growing back without reversing. This scenario produces very few reversed directions which are only visible at some latitudes. We infer that it is impossible to reach the ratio of reversed to intermediate VGPs present in the paleomagnetic records if the excursions were not associated with a short period of reversed dipole field. Therefore, excursions should be regarded as two successive reversals bracketing an aborted polarity interval. We propose that the same underlying mechanisms prevail in both situations (excursions or reversals) and that below a certain strength the field reaches an unstable position which preludes either the achievement of a reversal or its return to the former polarity.

  18. Scaling properties of excursions in heartbeat dynamics

    NASA Astrophysics Data System (ADS)

    Reyes-Ramírez, I.; Guzmán-Vargas, L.

    2010-02-01

    In this work we study the excursions, defined as the number of beats to return to a local mean value, in heartbeat interval time series from healthy subjects and patients with congestive heart failure (CHF). First, we apply the segmentation procedure proposed by Bernaola-Galván et al. (Phys. Rev. Lett., 87 (2001) 168105), to nonstationary heartbeat time series to identify stationary segments with a local mean value. Next, we identify local excursions around the local mean value and construct the distributions to analyze the time organization and memory in the excursions sequences from the whole time series. We find that the cumulative distributions of excursions are consistent with a stretched exponential function given by g(x)~e-aτb, with a=1.09±0.15 (mean value±SD) and b=0.91±0.11 for healthy subjects and a=1.31±0.23 and b=0.77±0.13 for CHF patients. The cumulative conditional probability G(τ|τ0) is considered to evaluate if τ depends on a given interval τ0, that is, to evaluate the memory effect in excursion sequences. We find that the memory in excursions sequences under healthy conditions is characterized by the presence of clusters related to the fact that large excursions are more likely to be followed by large ones whereas for CHF data we do not observe this behavior. The presence of correlations in healthy data is confirmed by means of the detrended fluctuation analysis (DFA) while for CHF records the scaling exponent is characterized by a crossover, indicating that for short scales the sequences resemble uncorrelated noise.

  19. Soybean canopy reflectance modeling data sets

    NASA Technical Reports Server (NTRS)

    Ranson, K. J.; Biehl, L. L.; Daughtry, C. S. T.

    1984-01-01

    Numerous mathematical models of the interaction of radiation with vegetation canopies have been developed over the last two decades. However, data with which to exercise and validate these models are scarce. During three days in the summer of 1980, experiments are conducted with the objective of gaining insight about the effects of solar illumination and view angles on soybean canopy reflectance. In concert with these experiment, extensive measurements of the soybean canopies are obtained. This document is a compilation of the bidirectional reflectance factors, agronomic, characteristics, canopy geometry, and leaf, stem, and pod optical properties of the soybean canopies. These data sets should be suitable for use with most vegetation canopy reflectance models.

  20. Nonstationary envelope process and first excursion probability.

    NASA Technical Reports Server (NTRS)

    Yang, J.-N.

    1972-01-01

    The definition of stationary random envelope proposed by Cramer and Leadbetter, is extended to the envelope of nonstationary random process possessing evolutionary power spectral densities. The density function, the joint density function, the moment function, and the crossing rate of a level of the nonstationary envelope process are derived. Based on the envelope statistics, approximate solutions to the first excursion probability of nonstationary random processes are obtained. In particular, applications of the first excursion probability to the earthquake engineering problems are demonstrated in detail.

  1. Spatial occupancy models for large data sets

    USGS Publications Warehouse

    Johnson, Devin S.; Conn, Paul B.; Hooten, Mevin B.; Ray, Justina C.; Pond, Bruce A.

    2013-01-01

    Since its development, occupancy modeling has become a popular and useful tool for ecologists wishing to learn about the dynamics of species occurrence over time and space. Such models require presence–absence data to be collected at spatially indexed survey units. However, only recently have researchers recognized the need to correct for spatially induced overdisperison by explicitly accounting for spatial autocorrelation in occupancy probability. Previous efforts to incorporate such autocorrelation have largely focused on logit-normal formulations for occupancy, with spatial autocorrelation induced by a random effect within a hierarchical modeling framework. Although useful, computational time generally limits such an approach to relatively small data sets, and there are often problems with algorithm instability, yielding unsatisfactory results. Further, recent research has revealed a hidden form of multicollinearity in such applications, which may lead to parameter bias if not explicitly addressed. Combining several techniques, we present a unifying hierarchical spatial occupancy model specification that is particularly effective over large spatial extents. This approach employs a probit mixture framework for occupancy and can easily accommodate a reduced-dimensional spatial process to resolve issues with multicollinearity and spatial confounding while improving algorithm convergence. Using open-source software, we demonstrate this new model specification using a case study involving occupancy of caribou (Rangifer tarandus) over a set of 1080 survey units spanning a large contiguous region (108 000 km2) in northern Ontario, Canada. Overall, the combination of a more efficient specification and open-source software allows for a facile and stable implementation of spatial occupancy models for large data sets.

  2. Deep Reconstruction Models for Image Set Classification.

    PubMed

    Hayat, Munawar; Bennamoun, Mohammed; An, Senjian

    2015-04-01

    Image set classification finds its applications in a number of real-life scenarios such as classification from surveillance videos, multi-view camera networks and personal albums. Compared with single image based classification, it offers more promises and has therefore attracted significant research attention in recent years. Unlike many existing methods which assume images of a set to lie on a certain geometric surface, this paper introduces a deep learning framework which makes no such prior assumptions and can automatically discover the underlying geometric structure. Specifically, a Template Deep Reconstruction Model (TDRM) is defined whose parameters are initialized by performing unsupervised pre-training in a layer-wise fashion using Gaussian Restricted Boltzmann Machines (GRBMs). The initialized TDRM is then separately trained for images of each class and class-specific DRMs are learnt. Based on the minimum reconstruction errors from the learnt class-specific models, three different voting strategies are devised for classification. Extensive experiments are performed to demonstrate the efficacy of the proposed framework for the tasks of face and object recognition from image sets. Experimental results show that the proposed method consistently outperforms the existing state of the art methods.

  3. On the bound of first excursion probability

    NASA Technical Reports Server (NTRS)

    Yang, J. N.

    1969-01-01

    Method has been developed to improve the lower bound of the first excursion probability that can apply to the problem with either constant or time-dependent barriers. The method requires knowledge of the joint density function of the random process at two arbitrary instants.

  4. Ultrasonographic assessment of flexor tendon mobilization: effect of different protocols on tendon excursion.

    PubMed

    Korstanje, Jan-Wiebe H; Soeters, Johannes N M; Schreuders, Ton A R; Amadio, Peter C; Hovius, Steven E R; Stam, Henk J; Selles, Ruud W

    2012-03-07

    Different mobilization protocols have been proposed for rehabilitation after hand flexor tendon repair to provide tendon excursion sufficient to prevent adhesions. Several cadaver studies have shown that the position of the neighboring fingers influences tendon excursions of the injured finger. We hypothesized that the positions of adjacent fingers influence the long finger flexor digitorum profundus tendon excursion, measured both absolutely and relative to the surrounding tissue of the tendon. Long finger flexor digitorum profundus tendon excursions and surrounding tissue movement were measured in zone V in eleven healthy subjects during three different rehabilitation protocols and two experimental models: (1) an active four-finger mobilization protocol, (2) a passive four-finger mobilization protocol, (3) a modified Kleinert mobilization protocol, (4) an experimental modified Kleinert flexion mobilization model, and (5) an experimental modified Kleinert extension mobilization model. Tendon excursions were measured with use of a frame-to-frame analysis of high-resolution ultrasound images. The median absolute long finger flexor digitorum profundus tendon excursions were 23.4, 17.8, 10.0, 13.9, and 7.6 mm for the active four-finger mobilization protocol, the passive four-finger mobilization protocol, the modified Kleinert mobilization protocol, the experimental modified Kleinert flexion mobilization model, and the experimental modified Kleinert extension mobilization model, respectively, and these differences were all significant (p ≤ 0.041). The corresponding relative flexor digitorum profundus tendon excursions were 11.2, 8.5, 7.2, 10.4, and 5.6 mm. Active four-finger mobilization protocol excursions were significantly (p = 0.013) greater than passive four-finger mobilization protocol excursions but were not significantly greater than experimental modified Kleinert flexion mobilization model excursions (p =0.213). The present study demonstrated large and

  5. Axion excursions of the landscape during inflation

    NASA Astrophysics Data System (ADS)

    Palma, Gonzalo A.; Riquelme, Walter

    2017-07-01

    Because of their quantum fluctuations, axion fields had a chance to experience field excursions traversing many minima of their potentials during inflation. We study this situation by analyzing the dynamics of an axion field ψ , present during inflation, with a periodic potential given by v (ψ )=Λ4[1 -cos (ψ /f )]. By assuming that the vacuum expectation value of the field is stabilized at one of its minima, say, ψ =0 , we compute every n -point correlation function of ψ up to first order in Λ4 using the in-in formalism. This computation allows us to identify the distribution function describing the probability of measuring ψ at a particular amplitude during inflation. Because ψ is able to tunnel between the barriers of the potential, we find that the probability distribution function consists of a non-Gaussian multimodal distribution such that the probability of measuring ψ at a minimum of v (ψ ) different from ψ =0 increases with time. As a result, at the end of inflation, different patches of the Universe are characterized by different values of the axion field amplitude, leading to important cosmological phenomenology: (a) Isocurvature fluctuations induced by the axion at the end of inflation could be highly non-Gaussian. (b) If the axion defines the strength of standard model couplings, then one is led to a concrete realization of the multiverse. (c) If the axion corresponds to dark matter, one is led to the possibility that, within our observable Universe, dark matter started with a nontrivial initial condition, implying novel signatures for future surveys.

  6. Multiple Palaeoproterozoic carbon burial episodes and excursions

    NASA Astrophysics Data System (ADS)

    Martin, A. P.; Prave, A. R.; Condon, D. J.; Lepland, A.; Fallick, A. E.; Romashkin, A. E.; Medvedev, P. V.; Rychanchik, D. V.

    2015-08-01

    Organic-rich rocks (averaging 2-5% total organic carbon) and positive carbonate-carbon isotope excursions (δ13C > + 5 ‰ and locally much higher, i.e. the Lomagundi-Jatuli Event) are hallmark features of Palaeoproterozoic successions and are assumed to archive a global event of unique environmental conditions following the c. 2.3 Ga Great Oxidation Event. Here we combine new and published geochronology that shows that the main Palaeoproterozoic carbon burial episodes (CBEs) preserved in Russia, Gabon and Australia were temporally discrete depositional events between c. 2.10 and 1.85 Ga. In northwest Russia we can also show that timing of the termination of the Lomagundi-Jatuli Event may have differed by up to 50 Ma between localities, and that Ni mineralisation occurred at c. 1920 Ma. Further, CBEs have traits in common with Mesozoic Oceanic Anoxic Events (OAEs); both are exceptionally organic-rich relative to encasing strata, associated with contemporaneous igneous activity and marked by organic carbon isotope profiles that exhibit a stepped decrease followed by a stabilisation period and recovery. Although CBE strata are thicker and of greater duration than OAEs (100 s of metres versus metres, ∼106 years versus ∼105 years), their shared characteristics hint at a commonality of cause(s) and feedbacks. This suggests that CBEs represent processes that can be either basin-specific or global in nature and a combination of circumstances that are not unique to the Palaeoproterozoic. Our findings urge circumspection and re-consideration of models that assume CBEs are a Deep Time singularity.

  7. 46 CFR 115.204 - Permit to carry excursion party.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... issued an excursion permit will normally be required to meet the minimum stability, survival craft, life jacket, fire safety, and manning standards applicable to a vessel in the service for which the excursion...

  8. High-resolution palaeomagnetic records of the Laschamp geomagnetic excursion from the Blake Ridge

    NASA Astrophysics Data System (ADS)

    Mac Niocaill, C.; Bourne, M. D.; Thomas, A. L.; Henderson, G. M.

    2013-05-01

    Geomagnetic excursions are brief (1000s of years) deviations in geomagnetic field behaviour from that expected during 'normal secular' variation. The Laschamp excursion (~41 ka) was a global deviation in geomagnetic field behaviour. Previously published records suggest rapid changes in field direction and a concurrent substantial decrease in field intensity. Accurate dating of excursions and determinations of their durations from multiple locations is vital to our understanding to global field behaviour during these deviations. We present here high-resolution palaeomagnetic records of the Laschamp excursion obtained from two Ocean Drilling Program (ODP) Sites 1061 and 1062 on the Blake-Bahama Outer Ridge (ODP Leg 172) Relatively high sedimentation rates (~30-40 cm kyr-1) at these locations allow the determination of transitional field behaviour during the excursion. Despite their advantages, sedimentary records can be limited by the potential for unrecognized variations in sedimentation rates between widely spaced age-constrained boundaries. Rather than assuming a constant sedimentation rate between assigned age tie-points, we employ measurements of the concentration of 230Thxs in the sediment. 230Thxs is a constant flux proxy and may be used to assess variations in the sedimentation rates through the core sections of interest. Following this approach, we present a new age model for Site 1061 that allows us to better determine the temporal behaviour of the Laschamp excursion with greater accuracy and known uncertainty. Palaeomagnetic measurements of discrete samples from four cores reveal a single excursional feature, across an interval of 30 cm, associated with a broader palaeointensity low. The excursion is characterised by rapid transitions (less than 200 years) between a stable normal polarity and a partially-reversed, polarity. Peaks in inclination either side of the directional excursion indicate periods of time when the local field is dominated by vertical

  9. ODP Site 1063 (Bermuda Rise) revisited: Oxygen isotopes, excursions and paleointensity in the Brunhes Chron

    NASA Astrophysics Data System (ADS)

    Channell, J. E. T.; Hodell, D. A.; Curtis, J. H.

    2012-02-01

    An age model for the Brunhes Chron of Ocean Drilling Program (ODP) Site 1063 (Bermuda Rise) is constructed by tandem correlation of oxygen isotope and relative paleointensity data to calibrated reference templates. Four intervals in the Brunhes Chron where paleomagnetic inclinations are negative for both u-channel samples and discrete samples are correlated to the following magnetic excursions with Site 1063 ages in brackets: Laschamp (41 ka), Blake (116 ka), Iceland Basin (190 ka), Pringle Falls (239 ka). These ages are consistent with current age estimates for three of these excursions, but not for "Pringle Falls" which has an apparent age older than a recently published estimate by ˜28 kyr. For each of these excursions (termed Category 1 excursions), virtual geomagnetic poles (VGPs) reach high southerly latitudes implying paired polarity reversals of the Earth's main dipole field, that apparently occurred in a brief time span (<2 kyr in each case), several times shorter than the apparent duration of regular polarity transitions. In addition, several intervals of low paleomagnetic inclination (low and negative in one case) are observed both in u-channel and discrete samples at ˜318 ka (MIS 9), ˜412 ka (MIS 11) and in the 500-600 ka interval (MIS 14-15). These "Category 2" excursions may constitute inadequately recorded (Category 1) excursions, or high amplitude secular variation.

  10. In vivo excursion of the temporalis muscle-tendon unit using electrical stimulation: application in the design of smile restoration surgery following facial paralysis.

    PubMed

    Boahene, Kofi D O; Ishii, Lisa E; Byrne, Patrick J

    2014-01-01

    The temporalis muscle has the potential to substitute for the function of paralyzed facial muscles in a single-stage procedure when transferred as a muscle-tendon unit (MTU). To measure the available excursion of the temporalis MTU after release from the coronoid. DESIGN, SETTING, AND PARTICIPANTS Thirteen consecutive patients undergoing the temporalis MTU transfer procedure for facial reanimation participated in this study in an academic research setting. Using transcutaneous electrical stimulation of the temporalis muscle, excursion of the temporalis muscle after its release as an MTU was recorded. Tension was varied on the released tendon during electrical stimulation of the muscle to determine the optimal muscle length at which the maximum excursion could be achieved. The tendon was inserted at the modiolus at the determined muscle length, and excursion of the oral commissure was recorded. Excursion data were then measured from the video recordings. RESULTS The mean excursion of the temporalis tendon after its detachment from the mandible and stimulation at an optimized passive tension was 20.6 mm (range, 14-30 mm) (n = 9). Following tendon insertion, the mean oral commissure excursion was 15.5 mm (range, 8-23 mm) (n = 13). The temporalis MTU has adequate available excursion following mobilization for dynamic reanimation of the paralyzed face. Electrical stimulation of the released temporalis tendon gives useful information that is reproducible and can be an important intraoperative adjunct to setting the MTU at an optimal tension to maximize force generation and excursion. NA.

  11. Practices and Methods for Actualization of the Scientific Information in Art Excursions (Excursions and Cultural Heritage in the Contemporary World)

    ERIC Educational Resources Information Center

    Portnova, Tatiana V.

    2016-01-01

    The paper deals with various practices and methods for actualization of the scientific information in art excursions. The modern society is characterized by commitment to information richness. The range of cultural and historical materials used as the basis for art excursions is really immense. However if to consider the number of excursions with…

  12. Systematic Behavior of the Non-dipole Magnetic Field during the 32 ka Mono Lake Excursion

    NASA Astrophysics Data System (ADS)

    Negrini, R. M.; McCuan, D.; Cassata, W. S.; Channell, J. E.; Verosub, K. L.; Liddicoat, J. C.; Knott, J. R.; Coe, R. S.; Benson, L. V.; Sarna-Wojcicki, A.; Lund, S.; Horton, R.; Lopez, J.

    2012-12-01

    Paleomagnetic excursions are enigmatic phenomena that reveal geodynamo behavior in its transitional state and provide important refinements in age control for the late Pleistocene, a critical time period for the study of paleoclimate and human evolution. We report here on two widely separated, unusually detailed records of the Mono Lake excursion (MLE) from sedimentary sequences dated at 32 ka. One of the records is from Summer Lake, Oregon. The vector components of this new record faithfully reproduce the principle features of the MLE as recorded at the type localities around Mono Lake, CA, though with greater detail and higher amplitude. Radiocarbon dates on bulk organics in the Summer Lake record confirm the 32 ka age of the MLE. The other record is from the marine Irminger Basin off of eastern Greenland and is based on the measurement of discrete samples rather than u-channels. The associated VGP paths of the two records strongly suggest systematic field behavior that includes three loci of nondipole flux whose relative dominance oscillates through time. The staggered sequence followed by the two paths through each flux locus further suggests that both the demise and return of the main field floods zonally during the excursion. The composite path is also compatible with the VGPs of a 32 ka set of lavas from New Zealand and, notably, it does not include VGPs associated with the 40 ka Laschamp excursion. This confirms that these two excursions are distinct events and, more specifically, shows that it is the 32 ka Mono Lake excursion that is recorded in the sediments surrounding Mono Lake rather than the ~40 ka Laschamp excursion.

  13. Spinodal Instabilities and Super-Planckian Excursions in Natural Inflation

    NASA Astrophysics Data System (ADS)

    Albrecht, Andreas; Holman, R.; Richard, Benoit J.

    2015-05-01

    Models such as Natural Inflation that use pseudo-Nambu-Goldstone bosons as the inflaton are attractive for many reasons. However, they typically require trans-Planckian field excursions Δ Φ >MPl, due to the need for an axion decay constant f >MPl to have both a sufficient number of e -folds and values of ns,r consistent with data. Such excursions would in general require the addition of all other higher dimension operators consistent with symmetries, thus disrupting the required flatness of the potential and rendering the theory nonpredictive. We show that in the case of Natural Inflation, the existence of spinodal instabilities (modes with tachyonic masses) can modify the inflaton equations of motion to the point that versions of the model with f

  14. Isukasia area: Regional geological setting (includes excursion guide)

    NASA Technical Reports Server (NTRS)

    Nutman, A. P.; Rosing, M.

    1986-01-01

    A brief account of the geology of the Isukasis area is given and is biased toward the main theme of the itinerary for the area: What has been established about the protoliths of the early Archean rocks of the area - the Isua supracrustal belt and the Amitsoq gneisses? The area's long and complex tectonometamorphic history of events can be divided into episodes using a combination of dike chronology, isotopic, and petrological studies. The earliest dikes, the ca 3700 Ma Inaluk dikes, intrude the earliest (tonalitic) components of the Amitsoq gneisses but are themselves cut up by the injection of the younger (granitic and pegmatitic) phases of the Amitsoq gneisses of the area. The areas of low late Archean deformation, strongly deformed early Archean mafic rocks have coarse grained metamorphic segregations and are cut by virtually undeformed mid-Archean Tarssartoq (Ameralik) dikes devoid of metamorphic segregations. The shows that the area was affected by regional amphibolite facies metamorphism in the early Archean. Late Archean and Proterozoic metamorphic imprints are marked to very strong in the area. Much of the early Archean gneiss complex was already highly deformed when the mid-Archean Tarssartoq dikes were intruded.

  15. Undulator Changes Due To Temperature Excursions

    SciTech Connect

    Wolf, Zachary; Levashov, Yurii; Reese, Ed; /SLAC

    2010-11-17

    The temperature of the LCLS undulators has not been controlled during storage. The effects of the temperature excursions are documented in this note. After a number of LCLS undulators were tuned, fiducialized, and placed in storage anticipating their use, a test was made to ensure that their properties had not changed. The test revealed, however, that indeed the undulators had changed. Detailed study of this problem followed. We now believe that the gap of the undulators changes permanently when the undulators go through temperature excursions. We have tested the other possible cause, transportation, and do not see gap changes. In this note, we document how the undulators have changed since they were originally tuned. The undulators were tuned and fiducialized in the Magnetic Measurement Facility (MMF). Afterward, many of them (approximately 18) were taken to building 750 for storage during summer and fall 2007. Building 750 had no temperature control. The undulator temperatures went from 20 C, used for tuning, down to approximately 11 C during the winter. In January 2008, three of the undulators were brought back to the MMF for a check. All three undulators showed similar changes. Trajectories, phases, and most undulator properties stayed the same, but the fiducialization (beam axis position relative to tooling balls on the undulator) had changed. Further investigation showed that the undulator gap was altered in a periodic way along the magnetic axis with a net average gap change causing the fiducialization change. A new storage location in building 33 was found and future undulators were placed there. A failure in the temperature control, however, caused the undulators to get too hot. Again the gap changed, but with a different periodic pattern. This note documents the measured changes in the undulators. In particular, it shows the detailed history of undulator 39 which went through both negative and positive temperature excursions.

  16. Volcanic records of the Laschamp geomagnetic excursion from Mt Ruapehu, New Zealand

    NASA Astrophysics Data System (ADS)

    Ingham, E.; Turner, G. M.; Conway, C. E.; Heslop, D.; Roberts, A. P.; Leonard, G.; Townsend, D.; Calvert, A.

    2017-08-01

    We present palaeodirectional records of the Laschamp geomagnetic excursion from lavas on Mt Ruapehu, New Zealand. Fourteen lava flows on the northwestern and southern flanks of Mt Ruapehu, with 40Ar/39Ar weighted mean plateau ages that range from 46.3 ± 2.0 to 39.9 ± 1.4 ka, were studied. The youngest and older flows carry a normal polarity magnetization; however, six flows, dated between 46.3 ± 2.0 and 42.7 ± 1.8 ka, record excursional directions. Three of these flows record southerly palaeomagnetic declinations and negative inclinations that agree well with a published Laschamp record from the Auckland Volcanic Field (AVF). Together, the AVF and Mt Ruapehu lavas currently represent the only volcanic records of the Laschamp excursion outside the Chaîne des Puys region, France. Thus, they make an important contribution to the global set of Laschamp excursion records. Virtual geomagnetic pole (VGP) groups for the New Zealand and French records early in the excursion are compatible with a dipole-dominated field that rotated to an equatorial orientation while simultaneously decaying in strength. In contrast, younger excursional flows from France and New Zealand yield separate VGP groups, which suggest either that the field had a nondipolar morphology in this later phase, or that the VGP groups were not synchronous. 40Ar/39Ar ages for the Mt Ruapehu record are on average slightly older than published northern hemisphere ages and from the relative palaeointensity minimum in the GLOPIS sedimentary stack. Although few individual ages differ significantly at the 2σ level, the spread suggests an overall excursion duration that is longer than the currently accepted 1500 years. This age spread may result from excess Ar in magmas at the time of the eruption biasing the results to slightly older ages, or from non-synchronous excursional field behaviour at near-antipodal locations, or, possibly, a precursory phase prior to the main excursion.

  17. A Comparison of two Brunhes Chron Geomagnetic Excursions Recorded by Neighbouring North Atlantic Sites (ODP Sites 1062 and 1063)

    NASA Astrophysics Data System (ADS)

    Bourne, M.; Mac Niocaill, C.; Knudsen, M. F.; Thomas, A. L.; Henderson, G. M.

    2012-04-01

    A full picture of geomagnetic field behaviour during the Blake excursion is currently limited by a paucity of robust, high-resolution records of this ambiguous event. Some records seem to point towards a 'double-excursion' character whilst others fail to record the Blake excursion at all. We present here a high-resolution record of the Blake excursion obtained from Ocean Drilling Program (ODP) Site 1062 on the Blake Outer Ridge (ODP Leg 172). Palaeomagnetic measurements in three cores reveal a single excursional feature associated with a broad palaeointensity low, characterised by rapid transitions (less than 500 years) between a stable normal polarity and a fully-reversed, pseudo-stable polarity. A relatively high sedimentation rate (~10 cm kyr-1) allows the determination of transitional field behaviour during the excursion. Rather than assuming a constant sedimentation rate between assigned age tie-points, we employ measurements of 230Thxs concentrations in the sediment to assess variations in the sedimentation rates through the core sections of interest. This allows us to determine an age and duration for the two excursions with greater accuracy and known uncertainty. Our new age model gives an age of 127 ka for the midpoint of the Blake event at Site 1062. The age model also gives a duration for the directional excursion of 7.1±1.6 kyr. This duration is similar to that previously reported for the Iceland Basin Excursion (~185 ka) from the nearby Bermuda Rise (ODP Site 1063), which recorded a ~7-8 kyr event. Similarly, a high sedimentation rate (10-15 cm kyr-1) at this site allows a high-resolution reconstruction of the geomagnetic field behaviour during the Iceland Basin Excursion. The Site 1063 palaeomagnetic record suggests more complicated behaviour than that of the Blake excursion at Site 1062. Instead, transitional VGP paths are characterised by stop-and-go behaviour between VGP clusters that may be related to long-standing thermo-dynamic features of the

  18. A New High-Resolution Record of the Blake Geomagnetic Excursion from ODP Site 1062

    NASA Astrophysics Data System (ADS)

    Bourne, M. D.; Mac Niocaill, C.; Henderson, G. M.; Thomas, A. L.; Faurschou Knudsen, M.

    2010-12-01

    We present a high resolution record of the Blake geomagnetic excursion from Ocean Drilling Program (ODP) Site 1062 on the Blake-Bahama Outer Ridge. The excursion is recorded in three separate cores, with the high sedimentation rate (~10 cm/ka) at this location allowing the determination of transitional field behaviour during the excursion. A complex geometry is observed for the excursional geomagnetic field at the site. The directional records show an initial deviation from the expected directions across an interval of 1 m that achieves a completely reversed state, and then returns to normal polarity. A second, although less well-defined, short-lived phase of anomalous directions is observed immediately following the first event in two of the three cores. Measurements of the magnetic susceptibility show little variation through the core indicating that the concentration and grain size of the remanence carriers remain relatively constant during the studied interval. Measurements of the S-Ratio and remanence coercivity also remain constant through the sections of interest, and indicate magnetite to be the primary remanence carrier. The relatively homogeneous sediment enables the determination of two relative palaeointensity proxies by normalizing natural remanent magnetization measurements using artificially induced magnetizations (anhysteretic remanence, ARM and isothermal remanence, IRM). These records are consistent between all three cores. The relative palaeointensity proxies suggest that the Earth's magnetic field decreased substantially in intensity several tens of kyr prior to the initial event, before reaching an intensity minimum coinciding with the directional excursion maximum. A second palaeointensity minimum is also observed after the excursional event with no associated directional change. These features are consistent with global palaeointensity stacks. Our age model uses a new oxygen isotope stratigraphy. However, rather than assuming a constant

  19. Carbon Isotopic Excursions Associated with the Mid-Pleistocene Transition and the Mid-Brunhes Transition

    NASA Astrophysics Data System (ADS)

    Barth, A. M.; Bill, N. S.; Clark, P. U.; Pisias, N. G.

    2015-12-01

    During the last 2 Myr, the climate system experienced two major transitions in variability: the mid-Pleistocene Transition (MPT), which represents a shift from dominant low-amplitude 41-kyr frequencies to dominant high-amplitude 100-kyr frequencies, and the mid-Brunhes Transition (MBT), which represents an increase in the amplitude of the 100-kyr frequency. While the MPT and MBT are typically identified in the benthic marine δ18O stack, their expression in other components of the climate system is less clear. Pleistocene δ13C records have been used to characterize climate and ocean circulation changes in response to orbital forcing, but these studies have used either a limited number of records or stacked data sets, which have the potential to bias the variability from the large number of young records. Here we present those existing δ13C data sets (n=18) that completely span these transitions. We use empirical orthogonal functions (EOFs) on these continuous data sets rather than stacking, allowing the determination of the dominant modes of variability and characterization of the time-frequency variation during the last 2 Myr. Our results identify two substantial carbon isotopic excursions. The first is a pronounced negative excursion during the MPT (~900 ka, MIS 23) that stands out as the strongest minimum in the last 2 Myr (previously identified from five records by Raymo et al., 1997). Corresponding ɛNd data from the South Atlantic suggest a strong weakening of the Atlantic meridional overturning circulation through the MIS 23 interglacial associated with this excursion. The second is a robust positive excursion ~530 ka (MIS 13), prior to the MBT (MIS 11), which stands out as the strongest maximum in the last 2 Myr. Possible causes of these excursions will be discussed.

  20. Diagnostic Models as Partially Ordered Sets

    ERIC Educational Resources Information Center

    Tatsuoka, Curtis

    2009-01-01

    In this commentary, the author addresses what is referred to as the deterministic input, noisy "and" gate (DINA) model. The author mentions concerns with how this model has been formulated and presented. In particular, the author points out that there is a lack of recognition of the confounding of profiles that generally arises and then discusses…

  1. 40 CFR 63.1438 - Parameter monitoring levels and excursions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., each excursion constitutes a violation of the emission limit. (ii) For each recovery or recapture... excursion constitutes a violation of the emission limit. (iii) For each combustion, recovery, or recapture... 75 percent of the operating hours. (iii) The period of combustion, recovery, or recapture...

  2. Standard fire behavior fuel models: a comprehensive set for use with Rothermel's surface fire spread model

    Treesearch

    Joe H. Scott; Robert E. Burgan

    2005-01-01

    This report describes a new set of standard fire behavior fuel models for use with Rothermel's surface fire spread model and the relationship of the new set to the original set of 13 fire behavior fuel models. To assist with transition to using the new fuel models, a fuel model selection guide, fuel model crosswalk, and set of fuel model photos are provided.

  3. Models for Propagation of NORAD Element Sets

    DTIC Science & Technology

    1980-12-01

    The SDP8 Model 56 10. The Deep-Space Subroutine 69 11. Driver and Function Subroutines 79 12. Users Guide, Constants, and Symbols 87 13. Sample Test ...LC_ . i4,- O-C .- , 46. 3 ’tS --, -S ,K3. O.CL4 , - . . .. .... .. . 61 XJ 3 ,XKE ,XKMPERoX4’, IPDA pAE 2- aO.UaL-E- 2.R.E.C.L S_L.OZ, -E2C CL S...13. SAMPLE TEST CASES V For reference a sample test case is given for each of the five models.* The input used was standard T-cards and the output is

  4. Quantitative Analysis of Single Particle Trajectories: Mean Maximal Excursion Method

    PubMed Central

    Tejedor, Vincent; Bénichou, Olivier; Voituriez, Raphael; Jungmann, Ralf; Simmel, Friedrich; Selhuber-Unkel, Christine; Oddershede, Lene B.; Metzler, Ralf

    2010-01-01

    An increasing number of experimental studies employ single particle tracking to probe the physical environment in complex systems. We here propose and discuss what we believe are new methods to analyze the time series of the particle traces, in particular, for subdiffusion phenomena. We discuss the statistical properties of mean maximal excursions (MMEs), i.e., the maximal distance covered by a test particle up to time t. Compared to traditional methods focusing on the mean-squared displacement we show that the MME analysis performs better in the determination of the anomalous diffusion exponent. We also demonstrate that combination of regular moments with moments of the MME method provides additional criteria to determine the exact physical nature of the underlying stochastic subdiffusion processes. We put the methods to test using experimental data as well as simulated time series from different models for normal and anomalous dynamics such as diffusion on fractals, continuous time random walks, and fractional Brownian motion. PMID:20371337

  5. Negative carbon isotope excursions caused by marine diagenesis during periods of non-deposition

    NASA Astrophysics Data System (ADS)

    Swart, P. K.; Oehlert, A. M.; Peterson, L. C.; Kroon, D.

    2016-12-01

    Negative carbon isotope excursions in marine carbonates are typically interpreted to be the result of diagenetic alteration by meteoric waters during subaerial exposure. However, new data from mixed carbonate and siliciclastic slope sediments collected by ODP Leg 133 adjacent to the Great Barrier Reef reveal a new mechanism for generating negative carbon isotope excursions in marine carbonates, where periods of non-deposition result in negative carbon isotope excursions in slope sediments that have never been subaerially exposed. In this proposed diagenetic model, these periods of non-deposition allow for an increased flux of sulfate into the pore waters, which removes the substrate limit on diagenetic reactions driven by sulfate reduction in pore waters of marine carbonates. As a result of the essentially unlimited supply of sulfate, negative carbon isotope excursions can be produced in marine carbonates deposited and preserved in periplatform and pelagic environments. Site specific age models constrained predominantly by records of δ18O values analyzed on G. ruber and Cibicides spp are supported by biostratigraphic age datums, magnetostratigraphy and gamma ray logs, and allow for reliable correlations and estimates of the duration of non-deposition at ODP Sites 819, 820, 823, and 811. Descriptions of the sedimentology, sulfate concentrations, and estimated length of time necessary for this model of diagenetic alteration to apply during periods of non-deposition will be presented, and implications for reconstructing global carbon cycle records will be discussed.

  6. Data Mining Using Extensions of the Rough Set Model.

    ERIC Educational Resources Information Center

    Lingras, P. J.; Yao, Y. Y.

    1998-01-01

    Examines basic issues of data mining using the theory of rough sets, a recent proposal for generalizing classical set theory. Demonstrates that a generalized rough set model can be used for generating rules from incomplete databases. Discusses the importance of rule extraction from incomplete databases in data mining. (AEF)

  7. A Logical Difficulty of the Parameter Setting Model.

    ERIC Educational Resources Information Center

    Sasaki, Yoshinori

    1990-01-01

    Seeks to prove that the parameter setting model (PSM) of Chomsky's Universal Grammar theory contains an internal contradiction when it is seriously taken to model the internal state of language learners. (six references) (JL)

  8. A Logical Difficulty of the Parameter Setting Model.

    ERIC Educational Resources Information Center

    Sasaki, Yoshinori

    1990-01-01

    Seeks to prove that the parameter setting model (PSM) of Chomsky's Universal Grammar theory contains an internal contradiction when it is seriously taken to model the internal state of language learners. (six references) (JL)

  9. ODP Site 1063 (Bermuda Rise) revisited: Oxygen isotopes, excursions and paleointensity in the Brunhes Chron

    NASA Astrophysics Data System (ADS)

    Channell, J. E.; Hodell, D. A.

    2011-12-01

    An age model for the Brunhes Chron for Ocean Drilling Program (ODP) Site 1063 (Bermuda Rise) is based on the tandem correlation of oxygen isotope and relative paleointensity data to calibrated reference templates. Four intervals in the Brunhes Chron where component inclinations are negative, for both u-channel samples and discrete samples, are correlated to the following magnetic excursions with Site 1063 ages in brackets: Laschamp (41 ka), Blake (116 ka), Iceland Basin (190 ka), Pringle Falls (239 ka). These ages are consistent with current age estimates for these excursion, other than for "Pringle Falls" which has an apparent age older than current estimates by ~20-30 kyrs. For each of these excursions, virtual geomagnetic poles (VGPs) reach high southerly latitudes implying paired polarity reversals in a brief time span (<2 kyr in each case) that is several times shorter than the observed duration of long-lived polarity transitions at mid-latitudes. Several intervals of low component inclinations, that are low and negative in one case, are observed both in u-channel and discrete samples at ~318 ka (MIS 9), ~413 ka (MIS 11) and in the 500-600 ka interval (MIS14-15). These may constitute inadequately recorded excursions, or high amplitude secular variation.

  10. The IIASA set of energy models: Its design and application

    NASA Astrophysics Data System (ADS)

    Basile, P. S.; Agnew, M.; Holzl, A.; Kononov, Y.; Papin, A.; Rogner, H. H.; Schrattenholzer, L.

    1980-12-01

    The models studied include an accounting framework type energy demand model, a dynamic linear programming energy supply and conversion system model, an input-output model, a macroeconomic model, and an oil trade gaming model. They are incorporated in an integrated set for long-term, global analyses. This set makes use of a highly iterative process for energy scenario projections and analyses. Each model is quite simple and straightforward in structure; a great deal of human judgement is necessary in applying the set. The models are applied to study two alternative energy scenarios for a coming fifty year period. Examples are presented revealing the wealth of information that can be obtained from multimodel techniques. Details are given for several models (equations employed, assumptions made, data used).

  11. Parameterization of Model Validating Sets for Uncertainty Bound Optimizations. Revised

    NASA Technical Reports Server (NTRS)

    Lim, K. B.; Giesy, D. P.

    2000-01-01

    Given measurement data, a nominal model and a linear fractional transformation uncertainty structure with an allowance on unknown but bounded exogenous disturbances, easily computable tests for the existence of a model validating uncertainty set are given. Under mild conditions, these tests are necessary and sufficient for the case of complex, nonrepeated, block-diagonal structure. For the more general case which includes repeated and/or real scalar uncertainties, the tests are only necessary but become sufficient if a collinearity condition is also satisfied. With the satisfaction of these tests, it is shown that a parameterization of all model validating sets of plant models is possible. The new parameterization is used as a basis for a systematic way to construct or perform uncertainty tradeoff with model validating uncertainty sets which have specific linear fractional transformation structure for use in robust control design and analysis. An illustrative example which includes a comparison of candidate model validating sets is given.

  12. The Record of Geomagnetic Excursions from a ~150 m Sediment Core: Clear Lake, Northern California

    NASA Astrophysics Data System (ADS)

    Levin, E.; Byrne, R.; Looy, C. V.; Wahl, D.; Noren, A. J.; Verosub, K. L.

    2015-12-01

    We are studying the paleomagnetic properties of a new ~150 meter drill core from Clear Lake, CA. Step-wise demagnetization of the natural remanent magnetism (NRM) yields stable directions after 20 mT, implying that the sediments are reliable recorders of geomagnetic field behavior. Several intervals of low relative paleointensity (RPI) from the core appear to be correlated with known geomagnetic excursions. At about 46 m depth, and ~33 ka according to an age model based on radiocarbon dates obtained from pollen and the Olema ash bed, a low RPI zone seems to agree with the age and duration of the Mono Lake Excursion, previously identified between 32 and 35 ka. Slightly lower in the core, at about 50 m depth and ~40 ka, noticeably low RPI values seem to be coeval with the Laschamp excursion, which has been dated at ~41 ka. A volcanic ash near the bottom of the core (141 mblf) is near the same depth as an ash identified in 1988 by Andrei Sarna-Wojcicki and others as the Loleta ash bed in a previous Clear Lake core. If the basal ash in the new core is indeed the, Loleta ash bed, then the core may date back to about 270-300 ka. Depending on the age of the lowest ash, a sequence of low RPI intervals could correlate with the Blake (120 ka), Iceland Basin (188 ka), Jamaica/Pringle Falls (211 ka), and CR0 (260 ka) excursions. Correlation of the low RPI intervals to these geomagnetic excursions will help in the development of a higher resolution chronostratigraphy for the core, resolve a long-standing controversy about a possible hiatus in the Clear Lake record, and provide information about climatically-driven changes in sedimentation.

  13. Gaussian predictive process models for large spatial data sets.

    PubMed

    Banerjee, Sudipto; Gelfand, Alan E; Finley, Andrew O; Sang, Huiyan

    2008-09-01

    With scientific data available at geocoded locations, investigators are increasingly turning to spatial process models for carrying out statistical inference. Over the last decade, hierarchical models implemented through Markov chain Monte Carlo methods have become especially popular for spatial modelling, given their flexibility and power to fit models that would be infeasible with classical methods as well as their avoidance of possibly inappropriate asymptotics. However, fitting hierarchical spatial models often involves expensive matrix decompositions whose computational complexity increases in cubic order with the number of spatial locations, rendering such models infeasible for large spatial data sets. This computational burden is exacerbated in multivariate settings with several spatially dependent response variables. It is also aggravated when data are collected at frequent time points and spatiotemporal process models are used. With regard to this challenge, our contribution is to work with what we call predictive process models for spatial and spatiotemporal data. Every spatial (or spatiotemporal) process induces a predictive process model (in fact, arbitrarily many of them). The latter models project process realizations of the former to a lower dimensional subspace, thereby reducing the computational burden. Hence, we achieve the flexibility to accommodate non-stationary, non-Gaussian, possibly multivariate, possibly spatiotemporal processes in the context of large data sets. We discuss attractive theoretical properties of these predictive processes. We also provide a computational template encompassing these diverse settings. Finally, we illustrate the approach with simulated and real data sets.

  14. A new level set model for multimaterial flows

    SciTech Connect

    Starinshak, David P.; Karni, Smadar; Roe, Philip L.

    2014-01-08

    We present a new level set model for representing multimaterial flows in multiple space dimensions. Instead of associating a level set function with a specific fluid material, the function is associated with a pair of materials and the interface that separates them. A voting algorithm collects sign information from all level sets and determines material designations. M(M ₋1)/2 level set functions might be needed to represent a general M-material configuration; problems of practical interest use far fewer functions, since not all pairs of materials share an interface. The new model is less prone to producing indeterminate material states, i.e. regions claimed by more than one material (overlaps) or no material at all (vacuums). It outperforms existing material-based level set models without the need for reinitialization schemes, thereby avoiding additional computational costs and preventing excessive numerical diffusion.

  15. Geomagnetic excursions date early hominid migration to China

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-09-01

    Global-scale geomagnetic reversals, which are periods when the direction of Earth's magnetic field flips, leave imprints in magnetic minerals present in sediments. But so do smaller-scale, even local, changes in Earth's magnetic field direction. Paleomagnetists believe that the smaller-scale events represent “failed reversals” and refer to them as “geomagnetic excursions.” Scientists use geomagnetic excursions in sedimentary basins as markers to tie together events of Earth's history across the globe.

  16. The Mathematical Concept of Set and the 'Collection' Model.

    ERIC Educational Resources Information Center

    Fischbein, Efraim; Baltsan, Madlen

    1999-01-01

    Hypothesizes that various misconceptions held by students with regard to the mathematical set concept may be explained by the initial collection model. Study findings confirm the hypothesis. (Author/ASK)

  17. Demonstration of saw blade accuracy and excursion: a cadaveric comparison study of blade types used in total knee arthroplasty.

    PubMed

    Wetzel, Robert J; Shah, Ritesh R; Puri, Lalit

    2013-06-01

    In total knee arthroplasty, outcomes partly depend on accurate osteotomies and integrity of stabilizing structures. We compared accuracy and excursion between a conventional and an oscillating tip saw blade. Two sets of osteotomies were made on cadaveric knees. Bi-planar accuracy was compared using computer navigation, and excursion was compared using methylene blue. Wilcoxon-Mann-Whitney testing demonstrated no significant difference in blade accuracy (p=0.35). Blades were within 0.5 degrees of neutral coronally and 2.0 degrees sagittally. The oscillating tip blade demonstrated less dye markings on the surrounding tissues. Accurate osteotomies and soft tissue protection are critical to successful arthroplasties. Although comparative accuracy was equal, the oscillating tip blade exhibited less excursion displaying potential for less iatrogenic soft tissue injuries leading to catastrophic failure.

  18. A Set-Based Methodology for White Noise Modeling

    DTIC Science & Technology

    1995-09-01

    Prescribed by ANSI Std Z39-18 A. Set-Based Methodology for White Noise Modeling Fernando Paganini Electrical Engineering. MIS 116-81 California Ins t i tu...worst-case, statistics consistent with the stochastic point of view, and simple descriptions tha t allow for tractable worst-case analysis. The...Essentially two approaches are available t o assess the consequences of this error: one is to model the uncertainty in terms of a set of allowable

  19. A Model Evaluation Data Set for the Tropical ARM Sites

    DOE Data Explorer

    Jakob, Christian

    2008-01-15

    This data set has been derived from various ARM and external data sources with the main aim of providing modelers easy access to quality controlled data for model evaluation. The data set contains highly aggregated (in time) data from a number of sources at the tropical ARM sites at Manus and Nauru. It spans the years of 1999 and 2000. The data set contains information on downward surface radiation; surface meteorology, including precipitation; atmospheric water vapor and cloud liquid water content; hydrometeor cover as a function of height; and cloud cover, cloud optical thickness and cloud top pressure information provided by the International Satellite Cloud Climatology Project (ISCCP).

  20. Modeling sets of unordered points using highly eccentric ellipses

    NASA Astrophysics Data System (ADS)

    Gerogiannis, Demetrios; Nikou, Christophoros; Likas, Aristidis

    2014-12-01

    An algorithm for modeling a set of unordered two-dimensional points by line segments is presented. The points are modeled by highly eccentric ellipses, and line segments are extracted by the major axes of these elongated ellipses. At first, a single ellipse is fitted to points which is then iteratively split to a large number of highly eccentric ellipses to cover the set of points. Then, a merge process follows in order to combine neighboring ellipses with almost collinear major axes to reduce the complexity of the model. Experimental results on various databases show that the proposed scheme is an efficient technique for modeling unordered sets of points and shapes by line segments. A computer vision application of the method is also presented regarding the detection of retinal fundus image features, such as end-points, junctions, and crossovers.

  1. Comparisons of thermospheric density data sets and models

    NASA Astrophysics Data System (ADS)

    Doornbos, Eelco; van Helleputte, Tom; Emmert, John; Drob, Douglas; Bowman, Bruce R.; Pilinski, Marcin

    During the past decade, continuous long-term data sets of thermospheric density have become available to researchers. These data sets have been derived from accelerometer measurements made by the CHAMP and GRACE satellites and from Space Surveillance Network (SSN) tracking data and related Two-Line Element (TLE) sets. These data have already resulted in a large number of publications on physical interpretation and improvement of empirical density modelling. This study compares four different density data sets and two empirical density models, for the period 2002-2009. These data sources are the CHAMP (1) and GRACE (2) accelerometer measurements, the long-term database of densities derived from TLE data (3), the High Accuracy Satellite Drag Model (4) run by Air Force Space Command, calibrated using SSN data, and the NRLMSISE-00 (5) and Jacchia-Bowman 2008 (6) empirical models. In describing these data sets and models, specific attention is given to differences in the geo-metrical and aerodynamic satellite modelling, applied in the conversion from drag to density measurements, which are main sources of density biases. The differences in temporal and spa-tial resolution of the density data sources are also described and taken into account. With these aspects in mind, statistics of density comparisons have been computed, both as a function of solar and geomagnetic activity levels, and as a function of latitude and local solar time. These statistics give a detailed view of the relative accuracy of the different data sets and of the biases between them. The differences are analysed with the aim at providing rough error bars on the data and models and pinpointing issues which could receive attention in future iterations of data processing algorithms and in future model development.

  2. Controllable set analysis for planetary landing under model uncertainties

    NASA Astrophysics Data System (ADS)

    Long, Jiateng; Gao, Ai; Cui, Pingyuan

    2015-07-01

    Controllable set analysis is a beneficial method in planetary landing mission design by feasible entry state selection in order to achieve landing accuracy and satisfy entry path constraints. In view of the severe impact of model uncertainties on planetary landing safety and accuracy, the purpose of this paper is to investigate the controllable set under uncertainties between on-board model and the real situation. Controllable set analysis under model uncertainties is composed of controllable union set (CUS) analysis and controllable intersection set (CIS) analysis. Definitions of CUS and CIS are demonstrated and computational method of them based on Gauss pseudospectral method is presented. Their applications on entry states distribution analysis under uncertainties and robustness of nominal entry state selection to uncertainties are illustrated by situations with ballistic coefficient, lift-to-drag ratio and atmospheric uncertainty in Mars entry. With analysis of CUS and CIS, the robustness of entry state selection and entry trajectory to model uncertainties can be guaranteed, thus enhancing the safety, reliability and accuracy under model uncertainties during planetary entry and landing.

  3. Computerized reduction of elementary reaction sets for combustion modeling

    NASA Technical Reports Server (NTRS)

    Wikstrom, Carl V.

    1991-01-01

    If the entire set of elementary reactions is to be solved in the modeling of chemistry in computational fluid dynamics, a set of stiff ordinary differential equations must be integrated. Some of the reactions take place at very high rates, requiring short time steps, while others take place more slowly and make little progress in the short time step integration. The goal is to develop a procedure to automatically obtain sets of finite rate equations, consistent with a partial equilibrium assumptions, from an elementary set appropriate to local conditions. The possibility of computerized reaction reduction was demonstrated. However, the ability to use the reduced reaction set depends on the ability of the CFD approach in incorporate partial equilibrium calculations into the computer code. Therefore, the results should be tested on a code with partial equilibrium capability.

  4. Computerized reduction of elementary reaction sets for CFD combustion modeling

    NASA Technical Reports Server (NTRS)

    Wikstrom, Carl V.

    1992-01-01

    Modeling of chemistry in Computational Fluid Dynamics can be the most time-consuming aspect of many applications. If the entire set of elementary reactions is to be solved, a set of stiff ordinary differential equations must be integrated. Some of the reactions take place at very high rates, requiring short time steps, while others take place more slowly and make little progress in the short time step integration.

  5. HDU Pressurized Excursion Module (PEM) Prototype Systems Integration

    NASA Technical Reports Server (NTRS)

    Gill, Tracy R.; Kennedy, Kriss; Tri, Terry; Toups, Larry; Howe, A. Scott

    2010-01-01

    The Habitat Demonstration Unit (HDU) project team constructed an analog prototype lunar surface laboratory called the Pressurized Excursion Module (PEM). The prototype unit subsystems were integrated in a short amount of time, utilizing a skunk-works approach that brought together over 20 habitation-related technologies from a variety of NASA centers. This paper describes the system integration strategies and lessons learned, that allowed the PEM to be brought from paper design to working field prototype using a multi-center team. The system integration process included establishment of design standards, negotiation of interfaces between subsystems, and scheduling fit checks and installation activities. A major tool used in integration was a coordinated effort to accurately model all the subsystems using CAD, so that conflicts were identified before physical components came together. Some of the major conclusions showed that up-front modularity that emerged as an artifact of construction, such as the eight 45 degree "pie slices" making up the module whose steel rib edges defined structural mounting and loading points, dictated much of the configurational interfaces between the major subsystems and workstations. Therefore, 'one of the lessons learned included the need to use modularity as a tool for organization in advance, and to work harder to prevent non-critical aspects of the platform from dictating the modularity that may eventually inform the fight system.

  6. Learning Setting-Generalized Activity Models for Smart Spaces

    PubMed Central

    Cook, Diane J.

    2011-01-01

    The data mining and pervasive computing technologies found in smart homes offer unprecedented opportunities for providing context-aware services, including health monitoring and assistance to individuals experiencing difficulties living independently at home. In order to provide these services, smart environment algorithms need to recognize and track activities that people normally perform as part of their daily routines. However, activity recognition has typically involved gathering and labeling large amounts of data in each setting to learn a model for activities in that setting. We hypothesize that generalized models can be learned for common activities that span multiple environment settings and resident types. We describe our approach to learning these models and demonstrate the approach using eleven CASAS datasets collected in seven environments. PMID:21461133

  7. An experimental methodology for a fuzzy set preference model

    NASA Technical Reports Server (NTRS)

    Turksen, I. B.; Willson, Ian A.

    1992-01-01

    A flexible fuzzy set preference model first requires approximate methodologies for implementation. Fuzzy sets must be defined for each individual consumer using computer software, requiring a minimum of time and expertise on the part of the consumer. The amount of information needed in defining sets must also be established. The model itself must adapt fully to the subject's choice of attributes (vague or precise), attribute levels, and importance weights. The resulting individual-level model should be fully adapted to each consumer. The methodologies needed to develop this model will be equally useful in a new generation of intelligent systems which interact with ordinary consumers, controlling electronic devices through fuzzy expert systems or making recommendations based on a variety of inputs. The power of personal computers and their acceptance by consumers has yet to be fully utilized to create interactive knowledge systems that fully adapt their function to the user. Understanding individual consumer preferences is critical to the design of new products and the estimation of demand (market share) for existing products, which in turn is an input to management systems concerned with production and distribution. The question of what to make, for whom to make it and how much to make requires an understanding of the customer's preferences and the trade-offs that exist between alternatives. Conjoint analysis is a widely used methodology which de-composes an overall preference for an object into a combination of preferences for its constituent parts (attributes such as taste and price), which are combined using an appropriate combination function. Preferences are often expressed using linguistic terms which cannot be represented in conjoint models. Current models are also not implemented an individual level, making it difficult to reach meaningful conclusions about the cause of an individual's behavior from an aggregate model. The combination of complex aggregate

  8. Setting up virgin stress conditions in discrete element models

    PubMed Central

    Rojek, J.; Karlis, G.F.; Malinowski, L.J.; Beer, G.

    2013-01-01

    In the present work, a methodology for setting up virgin stress conditions in discrete element models is proposed. The developed algorithm is applicable to discrete or coupled discrete/continuum modeling of underground excavation employing the discrete element method (DEM). Since the DEM works with contact forces rather than stresses there is a need for the conversion of pre-excavation stresses to contact forces for the DEM model. Different possibilities of setting up virgin stress conditions in the DEM model are reviewed and critically assessed. Finally, a new method to obtain a discrete element model with contact forces equivalent to given macroscopic virgin stresses is proposed. The test examples presented show that good results may be obtained regardless of the shape of the DEM domain. PMID:27087731

  9. Setting conservation management thresholds using a novel participatory modeling approach.

    PubMed

    Addison, P F E; de Bie, K; Rumpff, L

    2015-10-01

    We devised a participatory modeling approach for setting management thresholds that show when management intervention is required to address undesirable ecosystem changes. This approach was designed to be used when management thresholds: must be set for environmental indicators in the face of multiple competing objectives; need to incorporate scientific understanding and value judgments; and will be set by participants with limited modeling experience. We applied our approach to a case study where management thresholds were set for a mat-forming brown alga, Hormosira banksii, in a protected area management context. Participants, including management staff and scientists, were involved in a workshop to test the approach, and set management thresholds to address the threat of trampling by visitors to an intertidal rocky reef. The approach involved trading off the environmental objective, to maintain the condition of intertidal reef communities, with social and economic objectives to ensure management intervention was cost-effective. Ecological scenarios, developed using scenario planning, were a key feature that provided the foundation for where to set management thresholds. The scenarios developed represented declines in percent cover of H. banksii that may occur under increased threatening processes. Participants defined 4 discrete management alternatives to address the threat of trampling and estimated the effect of these alternatives on the objectives under each ecological scenario. A weighted additive model was used to aggregate participants' consequence estimates. Model outputs (decision scores) clearly expressed uncertainty, which can be considered by decision makers and used to inform where to set management thresholds. This approach encourages a proactive form of conservation, where management thresholds and associated actions are defined a priori for ecological indicators, rather than reacting to unexpected ecosystem changes in the future. © 2015 The

  10. Influence of lateral excursion on vestibular cervical dental abfraction.

    PubMed

    Palomino-Gómez, Sandra P; Jeremias, Fabiano; Finoti, Livia S; Paredes-Coz, Gerson; Raveli, Dirceu B

    2011-01-01

    A study was performed to evaluate the influence of mandibular lateral excursion, group function and canine guidance on vestibular cervical dental abfraction (VCDA). Thirty-six individuals of both sexes, aged 20 to 45 years, with full natural dentition with at least one tooth with VCDA were selected at the San Marcos University Clinic. We evaluated number of teeth with VCDA per side (left and right), tooth type and lateral excursive movement (canine guidance or group function) affecting it. The results showed no statistical difference (p > 0.05). The tooth type most often showing VCDA was the first lower premolar, with 30.8% on the right side and 36.4% on the left. Moderate positive correlation was found between age and VCDA (R = 0.40). It is concluded that group function during lateral excursion may contribute to presence of VCDA.

  11. The Mono Lake excursion recorded in phonolitic lavas from Tenerife (Canary Islands): Paleomagnetic analyses and coupled K/Ar and Ar/Ar dating

    NASA Astrophysics Data System (ADS)

    Kissel, C.; Guillou, H.; Laj, C.; Carracedo, J. C.; Nomade, S.; Perez-Torrado, F.; Wandres, C.

    2011-08-01

    We present a coupled paleomagnetic/dating investigation conducted on three different lava flows from the island of Tenerife (Canary Islands; Spain) erupted during the Mono Lake excursion (MLE). Paleomagnetic analyses consist in zero field demagnetizations (AF and/or thermal) and of Thellier and Thellier experiments using the PICRIT-03 set of criteria to select reliable intensity determinations. One of the flows is characterized by a direction largely deviated from the one expected from an axial geocentric dipole (GAD) field. Its paleointensity value is very low (7.8 μT). The two other sites are characterized by inclinations slightly shallower than the GAD value and by low intensity values (about 12 and 21 μT; present value: 38 μT). The three K/Ar ages combined with two 40Ar/ 39Ar ages range from 32.0 to 33.2 ka and they are not statistically distinguishable from one another. It therefore appears that these lavas have recorded the MLE (the only excursion in this time interval) confirming its brief duration (shorter than the minimum age uncertainties available). The mean age is younger but, within the uncertainties, consistent with the age of the 10Be peak and of the marine intensity low when reported in the most recent ice age model. These new results are the first ones with radiometric dating produced from the northern hemisphere. Combined with existing cosmogenic, marine and volcanic paleomagnetic data, these results are discussed in terms of dating, and geometry of the earth magnetic field during the excursion.

  12. Localization of compact invariant sets of the Lorenz' 1984 model

    NASA Astrophysics Data System (ADS)

    Starkov, K. E.

    In 1984 E. Lorenz published a paper [1] in which he proposed "the simplest possible general circulation model": dot{x} = -y^2 - z^2 - ax + aF, dot{y} = xy -bxz - y+G, dot{z} = bxy + xz -z which is referred to as the Lorenz'1984 model. The existence of chaos was shown in [1, 2] for different values of parameters. Dynamical studies of this system were realized in papers [1, 2]; [3], [4]. This paper is devoted to study of a localization problem of compact invariant sets of the Lorenz'1984 model with help of one approach elaborated in papers of Krishchenko and Starkov, see e.g. [5]. This problem is an important topic in studies of dynamics of a chaotic system because of the interest to a long-time behavior of a system. In this work we establish that all compact invariant sets of the Lorenz' 1984 model are contained in the set \\{ x le F;x^2 + y^2 + z^2 le η ^2 = {2left( {a + 2} right)F^2 + 3G^2 + 2Gsqrt {aF^2 + G^2 } }/4\\} . Further, we improve this localization with help of refining bound η using additional localizations sets. By applying cylindrical coordinates to the Lorenz' 1984 model we derive yet another localization set of the form \\{ y^2 + z^2 le G^2 (1 + b^{ - 2} )exp (4π b^{ - 1} )\\}. Finally, we discuss how to improve the final localization set and consider one example.

  13. Localization of compact invariant sets of the Lorenz' 1984 model

    NASA Astrophysics Data System (ADS)

    Starkov, K. E.

    In 1984 E. Lorenz published a paper [1] in which he proposed "the simplest possible general circulation model": dot{x} = -y^2 - z^2 - ax + aF, dot{y} = xy -bxz - y+G, dot{z} = bxy + xz -z which is referred to as the Lorenz'1984 model. The existence of chaos was shown in [1, 2] for different values of parameters. Dynamical studies of this system were realized in papers [1, 2]; [3], [4]. This paper is devoted to study of a localization problem of compact invariant sets of the Lorenz'1984 model with help of one approach elaborated in papers of Krishchenko and Starkov, see e.g. [5]. This problem is an important topic in studies of dynamics of a chaotic system because of the interest to a long-time behavior of a system. In this work we establish that all compact invariant sets of the Lorenz' 1984 model are contained in the set { x le F;x^2 + y^2 + z^2 le η ^2 = {2left( {a + 2} right)F^2 + 3G^2 + 2Gsqrt {aF^2 + G^2 } }/4} . Further, we improve this localization with help of refining bound η using additional localizations sets. By applying cylindrical coordinates to the Lorenz' 1984 model we derive yet another localization set of the form { y^2 + z^2 le G^2 (1 + b^{ - 2} )exp (4π b^{ - 1} )}. Finally, we discuss how to improve the final localization set and consider one example.

  14. Exploring the Angstrom Excursion of Au Nanoparticles Excited away from a Metal Surface by an Impulsive Acoustic Perturbation.

    PubMed

    Kim, Ji-Wan; Kovalenko, Oleksandr; Liu, Yu; Bigot, Jean-Yves

    2016-12-27

    We report the anharmonic angstrom dynamics of self-assembled Au nanoparticles (Au:NPs) away from a nickel surface on top of which they are coupled by their near-field interaction. The deformation and the oscillatory excursion away from the surface are induced by picosecond acoustic pulses and probed at the surface plasmon resonance with femtosecond laser pulses. The overall dynamics are due to an efficient transfer of translational momentum from the Ni surface to the Au:NPs, therefore avoiding usual thermal effects and energy redistribution among the electronic states. Two modes are clearly revealed by the oscillatory shift of the Au:NPs surface plasmon resonance-the quadrupole deformation mode due to the transient ellipsoid shape and the excursion mode when the Au:NPs bounce away from the surface. We find that, contrary to the quadrupole mode, the excursion mode is sensitive to the distance between Au:NPs and Ni. Importantly, the excursion dynamics display a nonsinusoidal motion that cannot be explained by a standard harmonic potential model. A detailed modeling of the dynamics using a Hamaker-type Lennard-Jones potential between two media is performed, showing that each Au:NPs coherently evolves in a nearly one-dimensional anharmonic potential with a total excursion of ∼1 Å. This excursion induces a shift of the surface plasmon resonance detectable because of the strong near-field interaction. This general method of observing the spatiotemporal dynamics with angstrom and picosecond resolutions can be directly transposed to many nanostructures or biosystems to reveal the interaction and contact mechanism with their surrounding medium while remaining in their fundamental electronic states.

  15. DIFFEOMORPHIC POINT SET REGISTRATION USING NON-STATIONARY MIXTURE MODELS.

    PubMed

    Wassermann, D; Ross, J; Washko, G; Westin, C-F; Estépar, R San José

    2013-01-01

    This paper investigates a diffeomorphic point-set registration based on non-stationary mixture models. The goal is to improve the non-linear registration of anatomical structures by representing each point as a general non-stationary kernel that provides information about the shape of that point. Our framework generalizes work done by others that use stationary models. We achieve this by integrating the shape at each point when calculating the point-set similarity and transforming it according to the calculated deformation. We also restrict the non-rigid transform to the space of symmetric diffeomorphisms. Our algorithm is validated in synthetic and human datasets in two different applications: fiber bundle and lung airways registration. Our results shows that non-stationary mixture models are superior to Gaussian mixture models and methods that do not take into account the shape of each point.

  16. Using Set Model for Learning Addition of Integers

    ERIC Educational Resources Information Center

    Lestari, Umi Puji; Putri, Ratu Ilma Indra; Hartono, Yusuf

    2015-01-01

    This study aims to investigate how set model can help students' understanding of addition of integers in fourth grade. The study has been carried out to 23 students and a teacher of IVC SD Iba Palembang in January 2015. This study is a design research that also promotes PMRI as the underlying design context and activity. Results showed that the…

  17. A Novel Multipurpose Model Set for Teaching General Chemistry.

    ERIC Educational Resources Information Center

    Gupta, H. O.; Parkash, Brahm

    1999-01-01

    Reports on a low-cost and unique molecular model set capable of generating a large number of structures for teaching and learning general chemistry. An important component of the kit is an 11-hole ball that gives tetrahedral, octahedral, trigonal, trigonal bipyramidal, and square planar symmetries. (WRM)

  18. Instruction manual model 600F, data transmission test set

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Information necessary for the operation and maintenance of the Model 600F Data Transmission Test Set is presented. A description is contained of the physical and functional characteristics; pertinent installation data; instructions for operating the equipment; general and detailed principles of operation; preventive and corrective maintenance procedures; and block, logic, and component layout diagrams of the equipment and its major component assemblies.

  19. A fuzzy set preference model for market share analysis

    NASA Technical Reports Server (NTRS)

    Turksen, I. B.; Willson, Ian A.

    1992-01-01

    Consumer preference models are widely used in new product design, marketing management, pricing, and market segmentation. The success of new products depends on accurate market share prediction and design decisions based on consumer preferences. The vague linguistic nature of consumer preferences and product attributes, combined with the substantial differences between individuals, creates a formidable challenge to marketing models. The most widely used methodology is conjoint analysis. Conjoint models, as currently implemented, represent linguistic preferences as ratio or interval-scaled numbers, use only numeric product attributes, and require aggregation of individuals for estimation purposes. It is not surprising that these models are costly to implement, are inflexible, and have a predictive validity that is not substantially better than chance. This affects the accuracy of market share estimates. A fuzzy set preference model can easily represent linguistic variables either in consumer preferences or product attributes with minimal measurement requirements (ordinal scales), while still estimating overall preferences suitable for market share prediction. This approach results in flexible individual-level conjoint models which can provide more accurate market share estimates from a smaller number of more meaningful consumer ratings. Fuzzy sets can be incorporated within existing preference model structures, such as a linear combination, using the techniques developed for conjoint analysis and market share estimation. The purpose of this article is to develop and fully test a fuzzy set preference model which can represent linguistic variables in individual-level models implemented in parallel with existing conjoint models. The potential improvements in market share prediction and predictive validity can substantially improve management decisions about what to make (product design), for whom to make it (market segmentation), and how much to make (market share

  20. Ocean sunfish rewarm at the surface after deep excursions to forage for siphonophores.

    PubMed

    Nakamura, Itsumi; Goto, Yusuke; Sato, Katsufumi

    2015-05-01

    Ocean sunfish (Mola mola) were believed to be inactive jellyfish feeders because they are often observed lying motionless at the sea surface. Recent tracking studies revealed that they are actually deep divers, but there has been no evidence of foraging in deep water. Furthermore, the surfacing behaviour of ocean sunfish was thought to be related to behavioural thermoregulation, but there was no record of sunfish body temperature. Evidence of ocean sunfish feeding in deep water was obtained using a combination of an animal-borne accelerometer and camera with a light source. Siphonophores were the most abundant prey items captured by ocean sunfish and were typically located at a depth of 50-200 m where the water temperature was <12 °C. Ocean sunfish were diurnally active, made frequently deep excursions and foraged mainly at 100-200 m depths during the day. Ocean sunfish body temperatures were measured under natural conditions. The body temperatures decreased during deep excursions and recovered during subsequent surfacing periods. Heat-budget models indicated that the whole-body heat-transfer coefficient between sunfish and the surrounding water during warming was 3-7 times greater than that during cooling. These results suggest that the main function of surfacing is the recovery of body temperature, and the fish might be able to increase heat gain from the warm surface water by physiological regulation. The thermal environment of ocean sunfish foraging depths was lower than their thermal preference (c. 16-17 °C). The behavioural and physiological thermoregulation enables the fish to increase foraging time in deep, cold water. Feeding rate during deep excursions was not related to duration or depth of the deep excursions. Cycles of deep foraging and surface warming were explained by a foraging strategy, to maximize foraging time with maintaining body temperature by vertical temperature environment. © 2015 The Authors. Journal of Animal Ecology © 2015

  1. Comparison of Tricuspid Annular Plane Systolic Excursion in Patients With Atrial Fibrillation Versus Sinus Rhythm.

    PubMed

    Torii, Yuta; Kusunose, Kenya; Yamada, Hirotsugu; Nishio, Susumu; Hirata, Yukina; Amano, Rie; Yamao, Masami; Bando, Mika; Hayashi, Shuji; Sata, Masataka

    2016-01-15

    Echocardiography now plays a central guiding role in the management of patients with atrial fibrillation (AF). However, the current guidelines mention little about the presence AF during the assessment of echocardiographic variables in the clinical setting. AF itself may impact on tricuspid annular plane systolic excursion (TAPSE) as a right ventricular systolic function compared with sinus rhythm (SR). The aim of this study was to compare and assess the echocardiographic parameters including TAPSE in patients with AF and SR. From January 1, 2013, to September 30, 2014, patients with AF without any cardiovascular disease were retrospectively evaluated using echocardiography. Age-, gender-, and left ventricular ejection fraction-matched patients with SR were selected from our database on the basis of a comprehensive history, physical examination, and echocardiographic findings. During the study period, we identified 239 patients with AF (74 ± 9 years; 65% men) and without any cardiac disease who underwent echocardiography. We also included 281 patients in the SR group (74 ± 8 years; 67% men). In all study subjects, TAPSE in AF was smaller than in SR regardless of age (17 ± 3 vs 20 ± 3 mm, p <0.001). In the stepwise multiple regression model, TAPSE was strongly associated with the presence of AF (standardized β = -0.362, p <0.001) and stroke volume index (standardized β = 0.173, p <0.001) after adjustment for age, gender, heart rate, left ventricular ejection fraction, and tricuspid regurgitant grade. In conclusions, patients with AF had lower TAPSE than those with SR regardless of age. When we assess TAPSE in the clinical setting, we must pay attention to the presence of AF. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Global Secular Variation and Excursions Within the Brunhes - is it Real?

    NASA Astrophysics Data System (ADS)

    Barckhausen, U.; Weske, M.

    2015-12-01

    We analyzed 64 high quality magnetic profiles crossing the Central Indian Ridge and the Southeast Indian Ridge between 21°S and 28°S. All profiles cover the entire Anomaly 1 and they do not cross discontinuities, major faults, or significant isolated bathymetric features. When stacked over single ridge segments, correlated variations in the magnetic field become apparent. However, these variations change from one ridge segment to the next and when stacked over the entire ridge, all correlated variations are lost. Therefore we conclude that the correlated variations represent local effects, in this case mainly caused by bathymetry and irregularities of the spreading process which are typically limited to one ridge segment. Since we do not see any anomalies associated to geomagnetic excursions, we carried out forward modelling which shows that any excursion lasting for longer than 10.000 years should become visible in our data, thus putting an upper limit of 10.000 years to the maximum duration of geomagnetic excursions during the Brunhes.

  3. A compressed marine data set for geomagnetic field modeling

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Baldwin, R. T.; Ridgway, J. R.; Davis, W. Minor

    1990-01-01

    Some 13 million scalar magnetic field data points that have been collected from the world's ocean areas reside in the collection of the National Geophysical Data Center. In order to derive a suitable data set for modeling the geomagnetic field of the earth, each ship track is divided into 220 km segments. The distribution of the reduced data in position, time and local time is discussed. The along-track filtering process described has proved to be an effective method of condensing large numbers of shipborne magnetic data into a manageable and meaningful data set for field modeling. This process also provides the benefits of smoothing short-wavelength crystal anomalies, discarding data recorded during magnetically noisy periods, and assigning reasonable error estimates to be utilized in the least squares modeling.

  4. A mesoscopic network model for permanent set in crosslinked elastomers

    SciTech Connect

    Weisgraber, T H; Gee, R H; Maiti, A; Clague, D S; Chinn, S; Maxwell, R S

    2009-01-29

    A mesoscopic computational model for polymer networks and composites is developed as a coarse-grained representation of the composite microstructure. Unlike more complex molecular dynamics simulations, the model only considers the effects of crosslinks on mechanical behavior. The elastic modulus, which depends only on the crosslink density and parameters in the bond potential, is consistent with rubber elasticity theory, and the network response satisfies the independent network hypothesis of Tobolsky. The model, when applied to a commercial filled silicone elastomer, quantitatively reproduces the experimental permanent set and stress-strain response due to changes in the crosslinked network from irradiation.

  5. Paleoproductivity And Carbon Cycling During The Middle Miocene Monterey Excursion

    NASA Astrophysics Data System (ADS)

    Billups, K.; Diester-Haass, L.; Emeis, K.; François, L.; Jacquemin, I.; Lefebvre, V.

    2010-05-01

    A prominent middle Miocene (17.5 to 13.5 Ma) carbon-isotope excursion (the so-called Monterey event) is punctuated by six distinct carbon isotope maxima (CM). Orbital tuning of carbon isotope records links each CM event with the long term component of eccentricity (400 kyr) highlighting the importance of insolation control on the global carbon cycle (Holbourn et al., 2008). Here we use proxy reconstructions (benthic foraminiferal accumulation rates) from six sites in the Atlantic and Pacific Oceans combined with geochemical modelling to investigate whether there is a link between long term insolation forcing and the marine carbon isotope record via marine productivity and thus atmospheric CO2 levels. Our results show that none of the CM events are associated with distinctly large changes in paleoproductivity. This observation is consistent with our previous finding that the overall mid Miocene carbon isotope maximum is not associated with a change in marine productivity (Diester-Haass et al., 2009). There are, albeit minor, fluctuations in productivity that can be related to the 400 kyr variability in the carbon isotope records with several productivity maxima between CM events, whereas CM events often show minima in productivity. Only the last of the CM events (CM 6), which occurs in close association with the major step in mid Miocene Antarctic ice growth, is accompanied by an ocean-wide increase in paleoproductivity. To tentatively explain the observed 400 kyr variability of the deep ocean carbon isotope record an improved version of the geochemical box model used Diester-Haass et al. (2009) has been forced by sealevel fluctuations reconstructed for the middle Miocene (Holbourn pers. comm., 2009). Calculations indicate that the induced changes in weathering rates and carbon cycle can explain the temporal variability of the carbon isotope record, but not the observed amplitude.

  6. Cardiac rehabilitation delivery model for low-resource settings.

    PubMed

    Grace, Sherry L; Turk-Adawi, Karam I; Contractor, Aashish; Atrey, Alison; Campbell, Norm; Derman, Wayne; Melo Ghisi, Gabriela L; Oldridge, Neil; Sarkar, Bidyut K; Yeo, Tee Joo; Lopez-Jimenez, Francisco; Mendis, Shanthi; Oh, Paul; Hu, Dayi; Sarrafzadegan, Nizal

    2016-09-15

    Cardiovascular disease is a global epidemic, which is largely preventable. Cardiac rehabilitation (CR) is demonstrated to be cost-effective and efficacious in high-income countries. CR could represent an important approach to mitigate the epidemic of cardiovascular disease in lower-resource settings. The purpose of this consensus statement was to review low-cost approaches to delivering the core components of CR, to propose a testable model of CR which could feasibly be delivered in middle-income countries. A literature review regarding delivery of each core CR component, namely: (1) lifestyle risk factor management (ie, physical activity, diet, tobacco and mental health), (2) medical risk factor management (eg, lipid control, blood pressure control), (3) education for self-management and (4) return to work, in low-resource settings was undertaken. Recommendations were developed based on identified articles, using a modified GRADE approach where evidence in a low-resource setting was available, or consensus where evidence was not. Available data on cost of CR delivery in low-resource settings suggests it is not feasible to deliver CR in low-resource settings as is delivered in high-resource ones. Strategies which can be implemented to deliver all of the core CR components in low-resource settings were summarised in practice recommendations, and approaches to patient assessment proffered. It is suggested that CR be adapted by delivery by non-physician healthcare workers, in non-clinical settings. Advocacy to achieve political commitment for broad delivery of adapted CR services in low-resource settings is needed. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  7. Cardiac rehabilitation delivery model for low-resource settings

    PubMed Central

    Grace, Sherry L; Turk-Adawi, Karam I; Contractor, Aashish; Atrey, Alison; Campbell, Norm; Derman, Wayne; Melo Ghisi, Gabriela L; Oldridge, Neil; Sarkar, Bidyut K; Yeo, Tee Joo; Lopez-Jimenez, Francisco; Mendis, Shanthi; Oh, Paul; Hu, Dayi; Sarrafzadegan, Nizal

    2016-01-01

    Objective Cardiovascular disease is a global epidemic, which is largely preventable. Cardiac rehabilitation (CR) is demonstrated to be cost-effective and efficacious in high-income countries. CR could represent an important approach to mitigate the epidemic of cardiovascular disease in lower-resource settings. The purpose of this consensus statement was to review low-cost approaches to delivering the core components of CR, to propose a testable model of CR which could feasibly be delivered in middle-income countries. Methods A literature review regarding delivery of each core CR component, namely: (1) lifestyle risk factor management (ie, physical activity, diet, tobacco and mental health), (2) medical risk factor management (eg, lipid control, blood pressure control), (3) education for self-management and (4) return to work, in low-resource settings was undertaken. Recommendations were developed based on identified articles, using a modified GRADE approach where evidence in a low-resource setting was available, or consensus where evidence was not. Results Available data on cost of CR delivery in low-resource settings suggests it is not feasible to deliver CR in low-resource settings as is delivered in high-resource ones. Strategies which can be implemented to deliver all of the core CR components in low-resource settings were summarised in practice recommendations, and approaches to patient assessment proffered. It is suggested that CR be adapted by delivery by non-physician healthcare workers, in non-clinical settings. Conclusions Advocacy to achieve political commitment for broad delivery of adapted CR services in low-resource settings is needed. PMID:27181874

  8. The impact of pH inhomogeneities on CHO cell physiology and fed-batch process performance - two-compartment scale-down modelling and intracellular pH excursion.

    PubMed

    Brunner, Matthias; Braun, Philipp; Doppler, Philipp; Posch, Christoph; Behrens, Dirk; Herwig, Christoph; Fricke, Jens

    2017-01-12

    Due to high mixing times and base addition from top of the vessel, pH inhomogeneities are most likely to occur during large-scale mammalian processes. The goal of this study was to set-up a scale-down model of a 10-12 m(3) stirred tank bioreactor and to investigate the effect of pH perturbations on CHO cell physiology and process performance. Short-term changes in extracellular pH are hypothesized to affect intracellular pH and thus cell physiology. Therefore, batch fermentations, including pH shifts to 9.0 and 7.8, in regular one-compartment systems are conducted. The short-term adaption of the cells intracellular pH are showed an immediate increase due to elevated extracellular pH. With this basis of fundamental knowledge, a two-compartment system is established which is capable of simulating defined pH inhomogeneities. In contrast to state-of-the-art literature, the scale-down model is included parameters (e.g. volume of the inhomogeneous zone) as they might occur during large-scale processes. pH inhomogeneity studies in the two-compartment system are performed with simulation of temporary pH zones of pH 9.0. The specific growth rate especially during the exponential growth phase is strongly affected resulting in a decreased maximum viable cell density and final product titer. The gathered results indicate that even short-term exposure of cells to elevated pH values during large-scale processes can affect cell physiology and overall process performance. In particular, it could be shown for the first time that pH perturbations, which might occur during the early process phase, have to be considered in scale-down models of mammalian processes.

  9. 5. Photocopy of photograph. JANE MOSELEY (VESSEL 53) DURING EXCURSION, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Photocopy of photograph. JANE MOSELEY (VESSEL 53) DURING EXCURSION, DETAIL OF FORE DECK AND CABIN AREA. Date end photographer unknown. (Original in Mariners Museum, Newport News, Virginia, negative #PB 30017) - Shooters Island, Ships Graveyard, Vessel No. 53, Newark Bay, Staten Island (subdivision), Richmond County, NY

  10. Excursion behaviour of female roe deer may depend on density.

    PubMed

    Bocci, A; Aiello, V; Lovari, S

    2013-07-01

    The excursion behaviour of roe does was studied for two years in a low density population (ca. 6.5 ind./100 ha), in an Apennine-continental forest of Southern Italy, through satellite radiotracking. During the rutting period, our radiotagged does (N=6) moved well outside their summer ranges, with an average exploration area eight times greater than summer ranges. The median duration of excursions was 51 h (range: 10-99 h). One female stayed away for a total of 11 days. In order further to understand this behaviour, we reviewed all studies (N=6) dealing with excursion behaviour of roe does and carried out in areas where population density was assessed through the same method (i.e. drive counts). Out of five ecological parameters included in the analysis, excursion behaviour of roe does was found significantly and negatively associated only to population density: when density was low, the proportion of roaming does increased, probably because of the lower availability of "free" bucks during the short time of female oestrous.

  11. Waterborne norovirus outbreak during a summer excursion in Northern Italy.

    PubMed

    Di Bartolo, Ilaria; Pavoni, Enrico; Tofani, Silvia; Consoli, Marta; Galuppini, Elisa; Losio, Marina Nadia; Ruggeri, Franco Maria; Varisco, Giorgio

    2015-01-01

    In September 2011, an acute gastroenteritis outbreak affected 33 children in Northern Italy. Patients had drunk river water during an excursion. Identical GI.4 norovirus genomes were detected from one patient's stools and from the river water. Improper discharge of human sewage into the river may have caused this waterborne outbreak.

  12. Potential Cislunar and Interplanetary Proving Ground Excursion Trajectory Concepts

    NASA Technical Reports Server (NTRS)

    McGuire, Melissa L.; Strange, Nathan J.; Burke, Laura M.; MacDonald, Mark A.; McElrath, Timothy P.; Landau, Damon F.; Lantoine, Gregory; Hack, Kurt J.; Lopez, Pedro

    2016-01-01

    NASA has been investigating potential translunar excursion concepts to take place in the 2020s that would be used to test and demonstrate long duration life support and other systems needed for eventual Mars missions in the 2030s. These potential trajectory concepts could be conducted in the proving ground, a region of cislunar and near-Earth interplanetary space where international space agencies could cooperate to develop the technologies needed for interplanetary spaceflight. Enabled by high power Solar Electric Propulsion (SEP) technologies, the excursion trajectory concepts studied are grouped into three classes of increasing distance from the Earth and increasing technical difficulty: the first class of excursion trajectory concepts would represent a 90-120 day round trip trajectory with abort to Earth options throughout the entire length, the second class would be a 180-210 day round trip trajectory with periods in which aborts would not be available, and the third would be a 300-400 day round trip trajectory without aborts for most of the length of the trip. This paper provides a top-level summary of the trajectory and mission design of representative example missions of these three classes of excursion trajectory concepts.

  13. Nongeocentric axial dipole field behavior during the Mono Lake excursion

    NASA Astrophysics Data System (ADS)

    Negrini, Robert M.; McCuan, Daniel T.; Horton, Robert A.; Lopez, James D.; Cassata, William S.; Channell, James E. T.; Verosub, Kenneth L.; Knott, Jeffrey R.; Coe, Robert S.; Liddicoat, Joseph C.; Lund, Steven P.; Benson, Larry V.; Sarna-Wojcicki, Andrei M.

    2014-04-01

    A new record of the Mono Lake excursion (MLE) is reported from the Summer Lake Basin of Oregon, USA. Sediment magnetic properties indicate magnetite as the magnetization carrier and imply suitability of the sediments as accurate recorders of the magnetic field including relative paleointensity (RPI) variations. The magnitudes and phases of the declination, inclination, and RPI components of the new record correlate well with other coeval but lower resolution records from western North America including records from the Wilson Creek Formation exposed around Mono Lake. The virtual geomagnetic pole (VGP) path of the new record is similar to that from another high-resolution record of the MLE from Ocean Drilling Program (ODP) Site 919 in the Irminger Basin between Iceland and Greenland but different from the VGP path for the Laschamp excursion (LE), including that found lower in the ODP-919 core. Thus, the prominent excursion recorded at Mono Lake, California, is not the LE but rather one that is several thousands of years younger. The MLE VGP path contains clusters, the locations of which coincide with nonaxial dipole features found in the Holocene geomagnetic field. The clusters are occupied in the same time progression by VGPs from Summer Lake and the Irminger Basin, but the phase of occupation is offset, a behavior that suggests time-transgressive decay and return of the principal field components at the beginning and end of the MLE, respectively, leaving the nonaxial dipole features associated with the clusters dominant during the excursion.

  14. Stratigraphic Correlation of an Excursion at 22 kyr in the U.S. Great Basin - the Hilina Pali Excursion?

    NASA Astrophysics Data System (ADS)

    Liddicoat, J. C.; Coe, R. S.

    2013-12-01

    An unusually large secular variation of the geomagnetic field recorded in outcrops of pluvial Lake Russell sediment about 22 kyr old in the Mono Basin, CA, can be used for precise correlation to other lacustrine sections in the western U.S., and perhaps beyond. We present new AF and thermal demagnetization results for paired samples at 2-cm intervals between ash layers 7 and 8 of Lajoie (1968) in the bank of Wilson Creek that document an excursion having an inclination as low as 16 degrees and as high as 73 degrees, while the declination swings from 15 degrees west during the low inclination to 30 east when the inclination is high, and back to average northerly declination and expected inclination. The corresponding VGPs form a narrow clockwise-trending loop centered at about 50 N, 30 E. The Mono Lake Excursion (MLE; Liddicoat and Coe, 1979) occurs 1.7 m lower in the same section. The best estimates for the ages of the two excursions are about 22 and 32 kyr, based on 14-C dates (Cassata et al., 2010). About 150 km to the north, sediments of about the same age exposed along the Truckee River that were deposited in pluvial Lake Lahontan record a similar geomagnetic signature. Moreover, both the MLE and this excursion are exhibited at the appropriate levels in a sediment core taken from Pyramid Lake, the remnant of Lake Lahontan (Benson et al., 2008). Thus, this excursion is a valuable marker for high-resolution correlation of Quaternary sediments in the western U.S., especially when paired with the MLE. It is tempting to try to identify this geomagnetic feature with others of about the same age further away. On the island of Hawaii, Coe et al. (1978) discovered a lava flow on the Hilina Pali with a calibrated 14-C age of 21 +/-1 kyr that has an inclination about 30 degrees shallower and a paleointensity 60 percent lower than today. Later Teanby et al. (2002) documented an excursion with inclinations as low as -35 degrees, recorded by around 40 successive flows with

  15. Setting development goals using stochastic dynamical system models.

    PubMed

    Ranganathan, Shyam; Nicolis, Stamatios C; Bali Swain, Ranjula; Sumpter, David J T

    2017-01-01

    The Millennium Development Goals (MDG) programme was an ambitious attempt to encourage a globalised solution to important but often-overlooked development problems. The programme led to wide-ranging development but it has also been criticised for unrealistic and arbitrary targets. In this paper, we show how country-specific development targets can be set using stochastic, dynamical system models built from historical data. In particular, we show that the MDG target of two-thirds reduction of child mortality from 1990 levels was infeasible for most countries, especially in sub-Saharan Africa. At the same time, the MDG targets were not ambitious enough for fast-developing countries such as Brazil and China. We suggest that model-based setting of country-specific targets is essential for the success of global development programmes such as the Sustainable Development Goals (SDG). This approach should provide clear, quantifiable targets for policymakers.

  16. Setting development goals using stochastic dynamical system models

    PubMed Central

    Nicolis, Stamatios C.; Bali Swain, Ranjula; Sumpter, David J. T.

    2017-01-01

    The Millennium Development Goals (MDG) programme was an ambitious attempt to encourage a globalised solution to important but often-overlooked development problems. The programme led to wide-ranging development but it has also been criticised for unrealistic and arbitrary targets. In this paper, we show how country-specific development targets can be set using stochastic, dynamical system models built from historical data. In particular, we show that the MDG target of two-thirds reduction of child mortality from 1990 levels was infeasible for most countries, especially in sub-Saharan Africa. At the same time, the MDG targets were not ambitious enough for fast-developing countries such as Brazil and China. We suggest that model-based setting of country-specific targets is essential for the success of global development programmes such as the Sustainable Development Goals (SDG). This approach should provide clear, quantifiable targets for policymakers. PMID:28241057

  17. Spatial and temporal patterns of subtidal and intertidal crabs excursions

    NASA Astrophysics Data System (ADS)

    Silva, A. C. F.; Boaventura, D. M.; Thompson, R. C.; Hawkins, S. J.

    2014-01-01

    Highly mobile predators such as fish and crabs are known to migrate from the subtidal zone to forage in the intertidal zone at high-tide. The extent and variation of these habitat linking movements along the vertical shore gradient have not been examined before for several species simultaneously, hence not accounting for species interactions. Here, the foraging excursions of Carcinus maenas (L.), Necora puber (Linnaeus, 1767) and Cancer pagurus (Linnaeus, 1758) were assessed in a one-year mark-recapture study on two replicated rocky shores in southwest U.K. A comparison between the abundance of individuals present on the shore at high-tide with those present in refuges exposed at low-tide indicated considerable intertidal migration by all species, showing strong linkage between subtidal and intertidal habitats. Estimates of population size based on recapture of marked individuals indicated that an average of ~ 4000 individuals combined for the three crab species, can be present on the shore during one tidal cycle. There was also a high fidelity of individuals and species to particular shore levels. Underlying mechanisms for these spatial patterns such as prey availability and agonistic interactions are discussed. Survival rates were estimated using the Cormack-Jolly-Seber model from multi-recapture analysis and found to be considerably high with a minimum of 30% for all species. Growth rates were found to vary intraspecifically with size and between seasons. Understanding the temporal and spatial variations in predation pressure by crabs on rocky shores is dependent on knowing who, when and how many of these commercially important crab species depend on intertidal foraging. Previous studies have shown that the diet of these species is strongly based on intertidal prey including key species such as limpets; hence intertidal crab migration could be associated with considerable impacts on intertidal assemblages.

  18. Single High Fidelity Geometric Data Sets for LCM - Model Requirements

    DTIC Science & Technology

    2006-11-01

    Defence R&D Canada – Atlantic DEFENCE DÉFENSE & Single High Fidelity Geometric Data Sets for LCM – Model Requirements D. Brennan T. Koko K. Mackay M...Brennan T. Koko K. Mackay M. Norwood S. Tobin E. Teng J. Wallace Martec Limited Martec Limited 1888 Brunswick Street, Suite 400 Halifax...result in SPMs for use in LCM analysis of existing and future classes of Canadian naval vessels. D. Brennan, T. Koko , K. Mackay, M. Norwood, S. Tobin, E

  19. Rough set theory based prognostic classification models for hospice referral.

    PubMed

    Gil-Herrera, Eleazar; Aden-Buie, Garrick; Yalcin, Ali; Tsalatsanis, Athanasios; Barnes, Laura E; Djulbegovic, Benjamin

    2015-11-25

    This paper explores and evaluates the application of classical and dominance-based rough set theory (RST) for the development of data-driven prognostic classification models for hospice referral. In this work, rough set based models are compared with other data-driven methods with respect to two factors related to clinical credibility: accuracy and accessibility. Accessibility refers to the ability of the model to provide traceable, interpretable results and use data that is relevant and simple to collect. We utilize retrospective data from 9,103 terminally ill patients to demonstrate the design and implementation RST- based models to identify potential hospice candidates. The classical rough set approach (CRSA) provides methods for knowledge acquisition, founded on the relational indiscernibility of objects in a decision table, to describe required conditions for membership in a concept class. On the other hand, the dominance-based rough set approach (DRSA) analyzes information based on the monotonic relationships between condition attributes values and their assignment to the decision class. CRSA decision rules for six-month patient survival classification were induced using the MODLEM algorithm. Dominance-based decision rules were extracted using the VC-DomLEM rule induction algorithm. The RST-based classifiers are compared with other predictive and rule based decision modeling techniques, namely logistic regression, support vector machines, random forests and C4.5. The RST-based classifiers demonstrate average AUC of 69.74 % with MODLEM and 71.73 % with VC-DomLEM, while the compared methods achieve average AUC of 74.21 % for logistic regression, 73.52 % for support vector machines, 74.59 % for random forests, and 70.88 % for C4.5. This paper contributes to the growing body of research in RST-based prognostic models. RST and its extensions posses features that enhance the accessibility of clinical decision support models. While the non-rule-based methods

  20. The Latitudinal Excursion of Coronal Magnetic Field Lines in Response to Differential Rotation: MHD Simulations

    NASA Technical Reports Server (NTRS)

    Lionello, Roberto; Linker, Jon A.; Mikic, Zoran; Riley, Pete

    2006-01-01

    Solar energetic particles, which are believed to originate from corotating interacting regions (CIRS) at low heliographic latitude, were observed by the Ulysses spacecraft even as it passed over the Sun's poles. One interpretation of this result is that high-latitude field lines intercepted by Ulysses connect to low-latitude CIRs at much larger heliocentric distances. The Fisk model explains the latitudinal excursion of magnetic field lines in the solar corona and heliosphere as the inevitable consequence of the interaction of a tilted dipole in a differentially rotating photosphere with rigidly rotating coronal holes. We use a time-dependent three-dimensional magnetohydrodynamic (MHD) algorithm to follow the evolution of a simple model of the solar corona in response to the differential rotation of the photospheric magnetic flux. We examine the changes of the coronal-hole boundaries, the redistribution of the line-of-sight magnetic field, and the precession of field lines in the corona. Our results confirm the basic idea of the Fisk model, that differential rotation leads to changes in the heliographic latitude of magnetic field lines. However, the latitudinal excursion of magnetic field lines in this simple "tilted dipole" model is too small to explain the Ulysses observations. Although coronal holes in our model rotate more rigidly than do photospheric features (in general agreement with observations), they do not rotate strictly rigidly as assumed by Fisk. This basic difference between our model and Fisk's will be explored in the future by considering more realistic magnetic flux distributions, as observed during Ulysses polar excursions.

  1. The Latitudinal Excursion of Coronal Magnetic Field Lines in Response to Differential Rotation: MHD Simulations

    NASA Technical Reports Server (NTRS)

    Lionello, Roberto; Linker, Jon A.; Mikic, Zoran; Riley, Pete

    2006-01-01

    Solar energetic particles, which are believed to originate from corotating interacting regions (CIRS) at low heliographic latitude, were observed by the Ulysses spacecraft even as it passed over the Sun's poles. One interpretation of this result is that high-latitude field lines intercepted by Ulysses connect to low-latitude CIRs at much larger heliocentric distances. The Fisk model explains the latitudinal excursion of magnetic field lines in the solar corona and heliosphere as the inevitable consequence of the interaction of a tilted dipole in a differentially rotating photosphere with rigidly rotating coronal holes. We use a time-dependent three-dimensional magnetohydrodynamic (MHD) algorithm to follow the evolution of a simple model of the solar corona in response to the differential rotation of the photospheric magnetic flux. We examine the changes of the coronal-hole boundaries, the redistribution of the line-of-sight magnetic field, and the precession of field lines in the corona. Our results confirm the basic idea of the Fisk model, that differential rotation leads to changes in the heliographic latitude of magnetic field lines. However, the latitudinal excursion of magnetic field lines in this simple "tilted dipole" model is too small to explain the Ulysses observations. Although coronal holes in our model rotate more rigidly than do photospheric features (in general agreement with observations), they do not rotate strictly rigidly as assumed by Fisk. This basic difference between our model and Fisk's will be explored in the future by considering more realistic magnetic flux distributions, as observed during Ulysses polar excursions.

  2. Modelling gene and protein regulatory networks with answer set programming.

    PubMed

    Fayruzov, Timur; Janssen, Jeroen; Vermeir, Dirk; Cornelis, Chris; De Cock, Martine

    2011-01-01

    Recently, many approaches to model regulatory networks have been proposed in the systems biology domain. However, the task is far from being solved. In this paper, we propose an Answer Set Programming (ASP)-based approach to model interaction networks. We build a general ASP framework that describes the network semantics and allows modelling specific networks with little effort. ASP provides a rich and flexible toolbox that allows expanding the framework with desired features. In this paper, we tune our framework to mimic Boolean network behaviour and apply it to model the Budding Yeast and Fission Yeast cell cycle networks. The obtained steady states of these networks correspond to those of the Boolean networks.

  3. Adaptation of Clinical Prediction Models for Application in Local Settings

    PubMed Central

    Kappen, Teus H.; Vergouwe, Yvonne; van Klei, Wilton A.; van Wolfswinkel, Leo; Kalkman, Cor J.

    2012-01-01

    Background. When planning to use a validated prediction model in new patients, adequate performance is not guaranteed. For example, changes in clinical practice over time or a different case mix than the original validation population may result in inaccurate risk predictions. Objective. To demonstrate how clinical information can direct updating a prediction model and development of a strategy for handling missing predictor values in clinical practice. Methods. A previously derived and validated prediction model for postoperative nausea and vomiting was updated using a data set of 1847 patients. The update consisted of 1) changing the definition of an existing predictor, 2) reestimating the regression coefficient of a predictor, and 3) adding a new predictor to the model. The updated model was then validated in a new series of 3822 patients. Furthermore, several imputation models were considered to handle real-time missing values, so that possible missing predictor values could be anticipated during actual model use. Results. Differences in clinical practice between our local population and the original derivation population guided the update strategy of the prediction model. The predictive accuracy of the updated model was better (c statistic, 0.68; calibration slope, 1.0) than the original model (c statistic, 0.62; calibration slope, 0.57). Inclusion of logistical variables in the imputation models, besides observed patient characteristics, contributed to a strategy to deal with missing predictor values at the time of risk calculation. Conclusions. Extensive knowledge of local, clinical processes provides crucial information to guide the process of adapting a prediction model to new clinical practices. PMID:22427369

  4. Adaptation of clinical prediction models for application in local settings.

    PubMed

    Kappen, Teus H; Vergouwe, Yvonne; van Klei, Wilton A; van Wolfswinkel, Leo; Kalkman, Cor J; Moons, Karel G M

    2012-01-01

    When planning to use a validated prediction model in new patients, adequate performance is not guaranteed. For example, changes in clinical practice over time or a different case mix than the original validation population may result in inaccurate risk predictions. To demonstrate how clinical information can direct updating a prediction model and development of a strategy for handling missing predictor values in clinical practice. A previously derived and validated prediction model for postoperative nausea and vomiting was updated using a data set of 1847 patients. The update consisted of 1) changing the definition of an existing predictor, 2) reestimating the regression coefficient of a predictor, and 3) adding a new predictor to the model. The updated model was then validated in a new series of 3822 patients. Furthermore, several imputation models were considered to handle real-time missing values, so that possible missing predictor values could be anticipated during actual model use. Differences in clinical practice between our local population and the original derivation population guided the update strategy of the prediction model. The predictive accuracy of the updated model was better (c statistic, 0.68; calibration slope, 1.0) than the original model (c statistic, 0.62; calibration slope, 0.57). Inclusion of logistical variables in the imputation models, besides observed patient characteristics, contributed to a strategy to deal with missing predictor values at the time of risk calculation. Extensive knowledge of local, clinical processes provides crucial information to guide the process of adapting a prediction model to new clinical practices.

  5. Hip strength and star excursion balance test deficits of patients with chronic ankle instability.

    PubMed

    McCann, Ryan S; Crossett, Ian D; Terada, Masafumi; Kosik, Kyle B; Bolding, Brenn A; Gribble, Phillip A

    2017-11-01

    To examine isometric hip strength in those with and without CAI, and determine the degree of Star Excursion Balance Test (SEBT) variance explained by isometric hip strength. Single-blinded, cross-sectional, case-control study. Thirty individuals with CAI, 29 lateral ankle sprain (LAS) copers, and 26 healthy controls participated. We assessed dynamic postural control with the SEBT anterior (SEBT-ANT), posteromedial (SEBT-PM), and posterolateral (SEBT-PL) reaches, and isometric hip extension (EXT), abduction (ABD) and external rotation (ER) strength with hand-held dynamometry. The CAI and LAS coper groups' involved limbs and randomly selected limbs in controls were tested. Separate Kruskal-Wallis tests compared SEBT scores and isometric hip strength between groups. Backwards linear regression models determined the degree of SEBT variance explained by isometric hip strength. Statistical significance was set a priori at P<0.05. The CAI group had lower SEBT-ANT scores compared to LAS copers (P=0.03) and controls (P=0.03). The CAI group had lower ABD compared to LAS copers (P=0.03) and controls (P=0.02). The CAI group had lower ER compared to LAS copers (P=0.01) and controls (P=0.01). ER (R(2)=0.25, P=0.01) and ABD (R(2)=0.25, P=0.01) explained 25% of the CAI group's SEBT-PM and SEBT-PL variances, respectively. The CAI group had deficient dynamic postural control and isometric hip strength compared to LAS copers and controls. Additionally, the CAI group's isometric hip strength significantly influenced dynamic postural control performance. Future CAI rehabilitation strategies should consider hip muscular strengthening to facilitate improvements in dynamic postural control. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  6. A Whale of an Interest in Sea Creatures: The Learning Potential of Excursions

    ERIC Educational Resources Information Center

    Hedges, Helen

    2004-01-01

    Excursions, or field trips, are a common component of early childhood programs, seen as a means of enriching the curriculum by providing experiences with people, places, and things in the community. Although excursions have been used as a framework for research on children's memory development, research on the efficacy of excursions in terms of…

  7. The Laschamp and the Other Recent Events - Excursions or Reversals?

    NASA Astrophysics Data System (ADS)

    Valet, J.-P.

    2009-04-01

    The Laschamp event discovered by Norbert Bonhommet in lava flows of Massif Central (France) is the youngest and the most studied field excursion. Its geomagnetic origin has been controversial due to the existence of self-reversal processes. Taking advantage of new dated sites, we have studied 21 units including 12 new localities and found no new site with intermediate or reverse polarity was found. Ten sites have a normal polarity and all sites studied at Olby, Louchadière and Royat display intermediate but scattered directions. We confirm that reverse polarity flows are affected by self-reversals but we found that this is also the case for normal flows. A direct consequence is that self-reversals cannot be taken as responsible for the reverse directions but they likely contribute to generate dispersion. Thus despite complex magnetization, the geomagnetic origin of the Laschamp in the Chaîne des Puys is not questioned. The volcanic pole positions (VGPs) clearly indicate that the Laschamp event is associated with full reversed directions. The compilation of the most detailed records of excursions that occuured during the Brunhes and Matuyama chron shows that this situation is almost systematic. In all cases, at least one virtual geomagnetic pole (VGPs) is able to reach the opposite polarity. In the next step, we have computed different simulations of excursions during which the dipole progressively vanishes before growing back without reversing. This scenario produces very few reversed directions which are only visible at some latitudes. We infer that it is impossible to reach the ratio of reversed to intermediate VGPs present in the paleomagnetic records if the excursions were not associated with a short period of reversed dipole field. Therefore, excursions should be regarded as two successive reversals bracketing an aborted polarity interval. We propose that the same underlying mechanisms prevail in both situations (excursions or reversals) and that below a

  8. Maximizing Social Model Principles in Residential Recovery Settings

    PubMed Central

    Polcin, Douglas; Mericle, Amy; Howell, Jason; Sheridan, Dave; Christensen, Jeff

    2014-01-01

    Abstract Peer support is integral to a variety of approaches to alcohol and drug problems. However, there is limited information about the best ways to facilitate it. The “social model” approach developed in California offers useful suggestions for facilitating peer support in residential recovery settings. Key principles include using 12-step or other mutual-help group strategies to create and facilitate a recovery environment, involving program participants in decision making and facility governance, using personal recovery experience as a way to help others, and emphasizing recovery as an interaction between the individual and their environment. Although limited in number, studies have shown favorable outcomes for social model programs. Knowledge about social model recovery and how to use it to facilitate peer support in residential recovery homes varies among providers. This article presents specific, practical suggestions for enhancing social model principles in ways that facilitate peer support in a range of recovery residences. PMID:25364996

  9. Excursions in fluvial (dis)continuity

    USGS Publications Warehouse

    Grant, Gordon E.; O'Connor, James E.; Safran, Elizabeth

    2017-01-01

    Lurking below the twin concepts of connectivity and disconnectivity are their first, and in some ways, richer cousins: continuity and discontinuity. In this paper we explore how continuity and discontinuity represent fundamental and complementary perspectives in fluvial geomorphology, and how these perspectives inform and underlie our conceptions of connectivity in landscapes and rivers. We examine the historical roots of continuum and discontinuum thinking, and how much of our understanding of geomorphology rests on contrasting views of continuity and discontinuity. By continuum thinking we refer to a conception of geomorphic processes as well as geomorphic features that are expressed along continuous gradients without abrupt changes, transitions, or thresholds. Balance of forces, graded streams, and hydraulic geometry are all examples of this perspective. The continuum view has played a prominent role in diverse disciplinary fields, including ecology, paleontology, and evolutionary biology, in large part because it allows us to treat complex phenomena as orderly progressions and invoke or assume equilibrium processes that introduce order and prediction into our sciences.In contrast the discontinuous view is a distinct though complementary conceptual framework that incorporates non-uniform, non-progressive, and non-equilibrium thinking into understanding geomorphic processes and landscapes. We distinguish and discuss examples of three different ways in which discontinuous thinking can be expressed: 1) discontinuous spatial arrangements or singular events; 2) specific process domains generally associated with thresholds, either intrinsic or extrinsic; and 3) physical dynamics or changes in state, again often threshold-linked. In moving beyond the continuous perspective, a fertile set of ideas comes into focus: thresholds, non-equilibrium states, heterogeneity, catastrophe. The range of phenomena that is thereby opened up to scientific exploration similarly expands

  10. Final report for the flow excursion follow-on testing

    SciTech Connect

    Nash, C.A.; Walters, T.W.

    1992-08-05

    The purpose of the Mark 22 Flow Excursion Follow-On testing was to investigate the theory that approximately 15% of the flow bypassed the primary flow channels in previous testing, whereas the design called for only a 3% bypass. The results of the follow-on tests clearly confirmed this theory. The testing was performed in two phases. During the first phase, characterization tests performed during the earlier test program were repeated.

  11. On the Age of the Laschamp Geomagnetic Excursion

    NASA Astrophysics Data System (ADS)

    Guillou, H.; Singer, B.; Scaillet, S.; Laj, C.; Kissel, C.; Jicha, B.

    2004-12-01

    The Laschamp geomagnetic excursion is a critical tie-point found directly in deep sea sediment cores and revealed in polar ice as an abrupt change in the rate of cosmogenic nuclide flux. Despite the importance of this excursion to quantifying paleoclimate proxy records archived in sediment and ice, and to providing an independent calibration of the radiocarbon calendar, its timing remains poorly known. Previous K-Ar, 40Ar/39Ar, and U-Th isochron determinations from lava flows at the type locality in the Massif Central, France, vary widely, are imprecise, and suggest a mean age of about 46.2 +/- 2.5 ka (AƒA_A,A¿A,A 1/2 2sigma). Results of 6 new unspiked K-Ar and 13 40Ar/39Ar incremental heating experiments on subsamples from 3 sites on the Laschamp and Olby flows are concordant and give a weighted mean age of 40.4 +/- 1.1 ka (2sigma uncertainty including analytical sources only) that is 10% younger than the previous estimates. Considering that the 40K - 40Ar decay constant is not known to a precision better than AƒA_A,A¿A,A 1/2 2.4%, the most probable radioisotopic age for the Laschamp excursion is 40.4 +/- 2.0 ka (2sigma, analytical plus decay constant uncertainties). This new age for the Laschamp excursion agrees precisely with that deduced from the NAPIS-75 deep sea sediment paleointensity stack when calibrated against the GISP2 ice core chronology using the O isotopes in ice and the magnetic properties of the marine cores.

  12. Preference Mining Using Neighborhood Rough Set Model on Two Universes

    PubMed Central

    2016-01-01

    Preference mining plays an important role in e-commerce and video websites for enhancing user satisfaction and loyalty. Some classical methods are not available for the cold-start problem when the user or the item is new. In this paper, we propose a new model, called parametric neighborhood rough set on two universes (NRSTU), to describe the user and item data structures. Furthermore, the neighborhood lower approximation operator is used for defining the preference rules. Then, we provide the means for recommending items to users by using these rules. Finally, we give an experimental example to show the details of NRSTU-based preference mining for cold-start problem. The parameters of the model are also discussed. The experimental results show that the proposed method presents an effective solution for preference mining. In particular, NRSTU improves the recommendation accuracy by about 19% compared to the traditional method. PMID:28044074

  13. Preference Mining Using Neighborhood Rough Set Model on Two Universes.

    PubMed

    Zeng, Kai

    2016-01-01

    Preference mining plays an important role in e-commerce and video websites for enhancing user satisfaction and loyalty. Some classical methods are not available for the cold-start problem when the user or the item is new. In this paper, we propose a new model, called parametric neighborhood rough set on two universes (NRSTU), to describe the user and item data structures. Furthermore, the neighborhood lower approximation operator is used for defining the preference rules. Then, we provide the means for recommending items to users by using these rules. Finally, we give an experimental example to show the details of NRSTU-based preference mining for cold-start problem. The parameters of the model are also discussed. The experimental results show that the proposed method presents an effective solution for preference mining. In particular, NRSTU improves the recommendation accuracy by about 19% compared to the traditional method.

  14. Modeling cellular deformations using the level set formalism

    PubMed Central

    Yang, Liu; Effler, Janet C; Kutscher, Brett L; Sullivan, Sarah E; Robinson, Douglas N; Iglesias, Pablo A

    2008-01-01

    Background Many cellular processes involve substantial shape changes. Traditional simulations of these cell shape changes require that grids and boundaries be moved as the cell's shape evolves. Here we demonstrate that accurate cell shape changes can be recreated using level set methods (LSM), in which the cellular shape is defined implicitly, thereby eschewing the need for updating boundaries. Results We obtain a viscoelastic model of Dictyostelium cells using micropipette aspiration and show how this viscoelastic model can be incorporated into LSM simulations to recreate the observed protrusion of cells into the micropipette faithfully. We also demonstrate the use of our techniques by simulating the cell shape changes elicited by the chemotactic response to an external chemoattractant gradient. Conclusion Our results provide a simple but effective means of incorporating cellular deformations into mathematical simulations of cell signaling. Such methods will be useful for simulating important cellular events such as chemotaxis and cytokinesis. PMID:18652669

  15. Level Set Segmentation of Lumbar Vertebrae Using Appearance Models

    NASA Astrophysics Data System (ADS)

    Fritscher, Karl; Leber, Stefan; Schmölz, Werner; Schubert, Rainer

    For the planning of surgical interventions of the spine exact knowledge about 3D shape and the local bone quality of vertebrae are of great importance in order to estimate the anchorage strength of screws or implants. As a prerequisite for quantitative analysis a method for objective and therefore automated segmentation of vertebrae is needed. In this paper a framework for the automatic segmentation of vertebrae using 3D appearance models in a level set framework is presented. In this framework model information as well as gradient information and probabilities of pixel intensities at object edges in the unseen image are used. The method is tested on 29 lumbar vertebrae leading to accurate results, which can be useful for surgical planning and further analysis of the local bone quality.

  16. Age of the Mono Lake excursion and associated tephra

    USGS Publications Warehouse

    Benson, L.; Liddicoat, J.; Smoot, J.; Sarna-Wojcicki, A.; Negrini, R.; Lund, S.

    2003-01-01

    The Mono Lake excursion (MLE) is an important time marker that has been found in lake and marine sediments across much of the Northern Hemisphere. Dating of this event at its type locality, the Mono Basin of California, has yielded controversial results with the most recent effort concluding that the MLE may actually be the Laschamp excursion (Earth Planet. Sci. Lett. 197 (2002) 151). We show that a volcanic tephra (Ash #15) that occurs near the midpoint of the MLE has a date (not corrected for reservoir effect) of 28,620 ?? 300 14C yr BP (??? 32,400 GISP2 yr BP) in the Pyramid Lake Basin of Nevada. Given the location of Ash #15 and the duration of the MLE in the Mono Basin, the event occurred between 31,500 and 33,300 GISP2 yr BP, an age range consistent with the position and age of the uppermost of two paleointensity minima in the NAPIS-75 stack that has been associated with the MLE (Philos. Trans. R. Soc. London Ser. A 358 (2000) 1009). The lower paleointensity minimum in the NAPIS-75 stack is considered to be the Laschamp excursion (Philos. Trans. R. Soc. London Ser. A 358 (2000) 1009).

  17. Speckle tracking as a method to measure hemidiaphragm excursion.

    PubMed

    Goutman, Stephen A; Hamilton, James D; Swihart, Blake; Foerster, Bradley; Feldman, Eva L; Rubin, Jonathan M

    2017-01-01

    Diaphragm excursion measured via ultrasound may be an important imaging outcome measure of respiratory function. We developed a new method for measuring diaphragm movement and compared it to the more traditional M-mode method. Ultrasound images of the right and left hemidiaphragms were collected to compare speckle tracking and M-mode measurements of diaphragm excursion. Speckle tracking was performed using EchoInsight (Epsilon Imaging, Ann Arbor, Michigan). Six healthy subjects without a history of pulmonary diseases were included in this proof-of-concept study. Speckle tracking of the diaphragm is technically possible. Unlike M-mode, speckle tracking carries the advantage of reliable visualization and measurement of the left hemidiaphragm. Speckle tracking accounted for diaphragm movement simultaneously in the cephalocaudad and mediolateral directions, unlike M-mode, which is 1-dimensional. Diaphragm speckle tracking may represent a novel, more robust method for measuring diaphragm excursion, especially for the left hemidiaphragm. Muscle Nerve 55: 125-127, 2017. © 2016 Wiley Periodicals, Inc.

  18. On the geographic and stratigraphic variability of the Hirnantian positive carbon isotope excursion across Anticosti Island, Canada

    NASA Astrophysics Data System (ADS)

    Jones, D. S.; Fike, D. A.; Finnegan, S.; Fischer, W. W.

    2010-12-01

    The mass extinction at the end of the Ordovician Period was one of the most extreme diversity depletions of the Phanerozoic Eon. It is associated with widespread glaciation on the southern supercontinent Gondwana and with a globally documented positive carbon isotope excursion. Mixed carbonate-siliciclastic facies on the Anticosti Island carbonate ramp contain a complete and richly fossiliferous record of this important interval of Earth history. The Ellis Bay and Becscie formations straddle the Ordovician/Silurian boundary and record several cycles of glacioeustatic sea level fluctuations. We report new chemostratigraphic records for the depositional sequence associated with glaciation during the Hirnantian, the final stage of the Ordovician Period. High-resolution inorganic and organic carbon isotope data through the +4‰ positive isotope excursion provide an independent measure of time which provides a robust context for the stratigraphic record. The positive carbon isotope excursion in the Laframboise Member (Ellis Bay Formation) is shown to match the architecture of the organic carbon isotope excursions documented at the GSSPs for the base of the Hirnantian Stage and the base of the Silurian System. A lower excursion in the stratigraphy correlates with pre-Hirnantian excursions documented in the Upper Ordovician Katian Stage in Baltica. Discontinuities in the isotope record correspond to key lithologic transitions across the island, providing the foundation for a dischronous model of the deposition of the Hirnantian strata. The oncolite marker bed that defines the base of the Laframboise Member is time transgressive, with deposition proceeding across the basin from the distal western end to the proximal east; it likely represents sea level rise associated with partial deglaciation of Gondwana. The Fox Point Member (Becscie Formation) is also time transgressive, prograding from the east to the west as the carbonate factory filled the newly created

  19. Modeling decision support rule interactions in a clinical setting.

    PubMed

    Sordo, Margarita; Rocha, Beatriz H; Morales, Alfredo A; Maviglia, Saverio M; Oglio, Elisa Dell'Oglio; Fairbanks, Amanda; Aroy, Teal; Dubois, David; Bouyer-Ferullo, Sharon; Rocha, Roberto A

    2013-01-01

    Traditionally, rule interactions are handled at implementation time through rule task properties that control the order in which rules are executed. By doing so, knowledge about the behavior and interactions of decision rules is not captured at modeling time. We argue that this is important knowledge that should be integrated in the modeling phase. In this project, we build upon current work on a conceptual schema to represent clinical knowledge for decision support in the form of if then rules. This schema currently captures provenance of the clinical content, context where such content is actionable (i.e. constraints) and the logic of the rule itself. For this project, we borrowed concepts from both the Semantic Web (i.e., Ontologies) and Complex Adaptive Systems (CAS), to explore a conceptual approach for modeling rule interactions in an enterprise-wide clinical setting. We expect that a more comprehensive modeling will facilitate knowledge authoring, editing and update; foster consistency in rules implementation and maintenance; and develop authoritative knowledge repositories to promote quality, safety and efficacy of healthcare.

  20. High-resolution record of the Laschamp geomagnetic excursion at the Blake-Bahama Outer Ridge

    NASA Astrophysics Data System (ADS)

    Bourne, Mark D.; Mac Niocaill, Conall; Thomas, Alex L.; Henderson, Gideon M.

    2013-12-01

    Geomagnetic excursions are brief deviations of the geomagnetic field from behaviour expected during `normal secular' variation. The Laschamp excursion at ˜41 ka was one such deviation. Previously published records suggest rapid changes in field direction and a concurrent substantial decrease in field intensity associated with this excursion. Accurate dating of excursions, and determination of their durations from multiple locations, is vital to our understanding of global field behaviour during these deviations. We present here high-resolution palaeomagnetic records of the Laschamp excursion obtained from two Ocean Drilling Program (ODP) Sites, 1061 and 1062 on the Blake-Bahama Outer Ridge (ODP Leg 172). High sedimentation rates (˜30-40 cm kyr-1) at these locations allow determination of transitional field behaviour during the excursion. Palaeomagnetic measurements of discrete samples from four cores reveal a single excursional feature, across an interval of 30 cm, associated with a broader palaeointensity low. We determine the age and duration of the Laschamp excursion using a stratigraphy linked to the δ18O record from the Greenland ice cores. This chronology dates the Laschamp excursion at the Blake Ridge to 41.3 ka. The excursion is characterized by rapid transitions (less than 200 yr) between stable normal polarity and a partially reversed polarity state. The palaeointensity record is in good agreement between the two sites, revealing two prominent minima. The first minimum is associated with the Laschamp excursion at 41 ka and the second corresponds to the Mono Lake excursion at ˜35.5 ka. We determine that the directional excursion during the Laschamp at this location was no longer than ˜400 yr, occurring within a palaeointensity minimum that lasted 2000 yr. The Laschamp excursion at this location is much shorter in duration than the Blake and Iceland Basin excursions.

  1. Effects of Age and Bolus Volume on Velocity of Hyolaryngeal Excursion in Healthy Adults.

    PubMed

    Barikroo, Ali; Carnaby, Giselle; Crary, Michael

    2015-10-01

    Reduced movement velocity has been identified as a risk marker for movement impairment in older adults. Hyolaryngeal excursion is a key movement feature of normal swallowing function which is known to change with age and other extrinsic variables such as bolus volume. However, velocity of hyolaryngeal excursion has received limited attention in the literature on normal or abnormal swallowing. This study evaluated the effects of age and bolus volume on the velocity of hyoid and laryngeal excursion during swallowing in healthy adults. Forty-four healthy volunteers were grouped into three age bands (young: 20-35 years, middle age: 36-55 years, older: 56 ≥ years). All subjects swallowed 5 and 20 mL of thin liquid during fluoroscopic recording. Fluoroscopic images were extracted for each swallow representing the onset and maximum excursion positions of the hyoid and larynx. Superior and anterior excursion distance (excursion magnitude) and the time difference between rest and maximum excursion (excursion duration) were calculated. Velocity was calculated as a ratio of distance over time. Superior hyoid excursion magnitude was significantly increased for the 20 mL volume. Anterior laryngeal excursion magnitude was also significantly increased for the 20 mL volume. No kinematic duration measure demonstrated significant change across age or bolus conditions. Superior hyoid excursion velocity was significantly faster for the 20 mL volume. Superior and anterior laryngeal excursion velocity were significantly faster for the 20 mL volume only in the older group. Results of this study indicate that magnitude and velocity of hyoid and laryngeal excursion vary with age and volume. Comprising both excursion magnitude and duration, kinematic velocity may be a more complete metric to evaluate age-related swallowing performance.

  2. Facial paralysis grading system: a new and simple smile excursion score for evaluating facial reanimation surgery.

    PubMed

    Tzou, Chieh-Han John; Chuang, David Chwei-Chin; Chen, Hsin-Hung

    2015-02-01

    Various facial paralysis grading systems have been introduced to evaluate the results of both spontaneous recovery and facial palsy reconstruction. The aim of the present study was to introduce and evaluate an objective new and quick Smile Excursion Score system which is readily applicable and easy to follow. It has been applied over the past 25 years for preoperative and postoperative result evaluation of smile reconstruction at Chang Gung Memorial Hospital. A standardized evaluation method was described for the assessment of the upper lip movement preoperatively and postoperatively with at least 1 year follow-up after functioning muscle transplantation. The evaluation was scored by the number of maxillary teeth exposed when smiling with teeth showing. Reliability of this technique was assessed by using 3 independent examiners who each evaluated the smiles of 34 unilateral facial paralysis patients 4 times, creating 408 sets of measurements. The intraclass correlation coefficients for interrater and intrarater reliability exceeded 0.94, which is considered as excellent and reliable. Chuang's Smile Excursion Score system is simple, quick, and accurate in evaluating smile after reanimation of paralyzed face effecting free functional muscle transplantation with no additional tools.

  3. A Novel Erbium-Doped Fiber Amplifier Simulator for Gain Excursion Estimation in Multi-Channel Dynamic Optical Network

    NASA Astrophysics Data System (ADS)

    Roy, Sharbani; Priye, Vishnu

    2012-01-01

    A novel erbium-doped fiber amplifier simulator designed using the SIMULINK toolbox of MATLAB 7.0 (The MathWorks, Natick, MA, USA) is reported in this article. The present simulator has an ability to incorporate multi-channel amplification simultaneously in both the C- and L-bands. It is realized by defining new FUNCTION block sets and replacing the MATLAB FUNCTION block set reported earlier for multi-channel amplification. Spectral variation of gain for an erbium-doped fiber amplifier simulator is first verified in both the C- and L-bands. Next, the simulator is employed to study gain excursion in a multi-channel dynamic optical network, where the change in the gain excursion by varying the pump power has also been estimated. The present approach to estimate the gain excursion will find applications in quantifying inter-channel cross-talk due to cross-gain saturation among co-propagating multi-channels in a dynamic optical network.

  4. Excurrent jets of a set of model clams

    NASA Astrophysics Data System (ADS)

    Excurrent jets of a set of model clams that are discharging into the near-wall region of a turbulent boundary layer in a laboratory flume. These false-color images were produced using planar laser-induced fluorescence and represent 16-s averages of dye concentration fields associated with the excurrent jets. Fluid that leaves the excurrent siphone is dyed to represent phytoplankton-depleted fluid, whereas the clear ambient fluid represents phytoplanktonrich fluid. This particular sequence of images shows how the speed of the crossflow affects the food-depleted (high dye concentration) boundary layer that develops over the bed of clams in two different ways—through its direct effect on the trajectories of the excurrent jets and through its effect on turbulent mixing of the jets.

  5. Star Excursion Balance Test Anterior Asymmetry Is Associated With Injury Status in Division I Collegiate Athletes.

    PubMed

    Stiffler, Mikel R; Bell, David R; Sanfilippo, Jennifer L; Hetzel, Scott J; Pickett, Kristen A; Heiderscheit, Bryan C

    2017-05-01

    Study Design Retrospective cohort. Background Star Excursion Balance Test (SEBT) performance differs by sport in healthy collegiate athletes, and lower extremity injury rates also vary by sport, sex, and athletic exposure. The relationship between SEBT performance and injury risk has not been evaluated with consideration of these additional variables, which may be necessary to fully describe the relationship between SEBT performance and injury risk. Objectives To assess the association between preseason SEBT performance and noncontact injury occurrence to the knee or ankle in Division I collegiate athletes when controlling for sport, sex, and athletic exposure. Methods Star Excursion Balance Test performance, starting status, and injury status were reviewed retrospectively in National Collegiate Athletic Association Division I collegiate athletes from a single institution. A total of 147 athletes were healthy at the time of preseason SEBT testing and either remained healthy (n = 118) or sustained a noncontact injury to the knee or ankle (n = 29) during their sport's subsequent competitive season. Side-to-side asymmetries were calculated in each direction as the absolute difference in reach distance between limbs. Star Excursion Balance Test reach distances and asymmetries were compared between groups using multivariable regression, controlling for sport, sex, and athletic exposure (starter, nonstarter). Receiver operating characteristic curves were used to determine optimal sensitivity and specificity for significant models. Results When controlling for sport, sex, and athletic exposure, SEBT side-to-side asymmetry in the anterior direction, expressed as an absolute or normalized to limb length, discriminated between injured and noninjured athletes (area under the curve greater than 0.82). Conclusion Assessing side-to-side reach asymmetry in the anterior direction of the SEBT may assist in identifying collegiate athletes who are at risk for sustaining noncontact

  6. Setting up a model intercomparison project for the last deglaciation

    NASA Astrophysics Data System (ADS)

    Ivanovic, R. F.; Gregoire, L. J.; Valdes, P. J.; Roche, D. M.; Kageyama, M.

    2014-12-01

    The last deglaciation (~ 21-9 ka) presents a series of opportunities to study the underlying mechanisms of abrupt climate changes and long-term trends in the Earth System. Most of the forcings are relatively well constrained and geological archives record responses over a range of timescales. Despite this, large uncertainties remain over the feedback loops that culminated in the collapse of the great Northern Hemisphere ice sheets, and a consensus has yet to be reached on the chains of events that led to rapid surface warming and cooling during this period.Climate models are powerful tools for quantitatively assessing these outstanding issues through their ability to temporally resolve cause and effect, as well as break down the contributions from different forcings. This is well demonstrated by pioneering work; for example by Liu et al. (2009), Roche et al. (2011), Gregoire et al. (2012) and Menviel et al. (2011). However, such work is not without challenges; model-geological data mismatches remain unsolved and it is difficult to compare results from different models with unique experiment designs. Therefore, we have established a multidisciplinary Paleoclimate Model Intercomparison Project working group to coordinate transient climate model simulations and geological archive compilations of the last deglaciation. Here, we present the plans and progress of the working group in its first phase of activity; the investigation of Heinrich Stadial 1 and the lead into the Bolling warming event. We describe the set-up of the core deglacial experiment, explain our approach for dealing with uncertain climate forcings and outline our solutions to challenges posed by this research. By defining a common experiment design, we have built a framework to include models of different speeds, complexities and resolution, maximising the reward of this varied approach. One of the next challenges is to compile transient proxy records and develop a methodology for dealing with

  7. Qualitative optimization of image processing systems using random set modeling

    NASA Astrophysics Data System (ADS)

    Kelly, Patrick A.; Derin, Haluk; Vaidya, Priya G.

    2000-08-01

    Many decision-making systems involve image processing that converts input sensor data into output images having desirable features. Typically, the system user selects some processing parameters. The processor together with the input image can then be viewed as a system that maps the processing parameters into output features. However, the most significant output features often are not numerical quantities, but instead are subjective measures of image quality. It can be a difficult task for a user to find the processing parameters that give the 'best' output. We wish to automate this qualitative optimization task. The key to this is incorporation linguistic operating rules and qualitative output parameters in a numerical optimization scheme. In this paper, we use the test system of input parameter selection for 2D Wiener filtering to restore noisy and blurred images. Operating rules represented with random sets are used to generate a nominal input-output system model, which is then used to select initial Wiener filter input parameters. Whenthe nominally optimal Wiener filter is applied to an observed image, the operator's assessment of output image quality is used in an adaptive filtering algorithm to adjust the model and select new input parameters. Test on several images have confirmed that with a few such iterations, a significant improvement in output quality is achieved.

  8. Viscoelastic modeling and inversion of a marine data set

    SciTech Connect

    Minkoff, S.E.; Symes, W.W.

    1994-12-31

    Deterministic waveform inversion in the p-{tau} domain permits estimation of the long-wavelength p-wave background velocity, the short-wavelength elastic parameter fluctuations, and the energy source for a marine data set from the Gulf of Mexico. The forward map is a convolutional model for p-wave primaries-only seismograms of viscoelastic, layered media. Two types of inversion (output least squares and differential semblance optimization) allow efficient estimation of various parameter combinations. Background velocities computed by differential semblance optimization were as consistent kinematically as those produced by interactive migration velocity analysis and gave somewhat more accurate depths. Source parameters obtained by output least squares inversion permitted considerably better fit to data than did those produced by as air gun modeling package. Output least squares inversion gave very short-scale detail of major reflectors closely resembling the detail derived from well logs. Despite evidence of considerable lateral heterogeneity in the shallow subsurface, estimates of deeper reflectors were remarkably consistent from midpoint to midpoint.

  9. Potential for water-table excursions induced by seismic events at Yucca Mountain, Nevada

    NASA Astrophysics Data System (ADS)

    Carrigan, Charles R.; King, Geoffrey C. P.; Barr, George E.; Bixler, Nathan E.

    1991-12-01

    The possibility that 100-200 m changes in water-table elevation can be mechanically induced by earthquakes is a consideration in site studies of a potential high-level nuclear waste repository at Yucca Mountain, Nevada. However, numerical simulations of tectonohydrologic coupling involving earthquakes typical of the Basin and Range province produce 2-3 m excursions of a water table that is 500 m below the land surface. Even displacements corresponding to extraordinary seismic events drive water-table excursions of less than 20 m. Flow resulting from earthquake-induced pore-pressure fields below the water table tends to be mainly horizontal; vertical flows that cause changes of the level of the water table are secondary. Strongly anisotropic permeability, intended to enhance vertical flow within fault zones, only doubles water-table rise in the models considered. These simulations of water-table rise compare well with observations following large earthquakes in the Basin and Range. Our models suggest that exceptional hydrologic and/or tectonic conditions would be required to produce substantially larger water-table rises.

  10. A Diagnostic Scoring Model for Leptospirosis in Resource Limited Settings.

    PubMed

    Rajapakse, Senaka; Weeratunga, Praveen; Niloofa, Roshan; Fernando, Narmada; de Silva, Nipun Lakshitha; Rodrigo, Chaturaka; Maduranga, Sachith; Nandasiri, Nuwanthi; Premawansa, Sunil; Karunanayake, Lilani; de Silva, H Janaka; Handunnetti, Shiroma

    2016-06-01

    Leptospirosis is a zoonotic infection with significant morbidity and mortality. The clinical presentation of leptospirosis is known to mimic the clinical profile of other prevalent tropical fevers. Laboratory confirmation of leptospirosis is based on the reference standard microscopic agglutination test (MAT), direct demonstration of the organism, and isolation by culture and DNA detection by polymerase chain reaction (PCR) amplification. However these methods of confirmation are not widely available in resource limited settings where the infection is prevalent, and reliance is placed on clinical features for provisional diagnosis. In this prospective study, we attempted to develop a model for diagnosis of leptospirosis, based on clinical features and standard laboratory test results. The diagnostic score was developed based on data from a prospective multicentre study in two hospitals in the Western Province of Sri Lanka. All patients presenting to these hospitals with a suspected diagnosis of leptospirosis, based on the WHO surveillance criteria, were recruited. Confirmed disease was defined as positive genus specific MAT (Leptospira biflexa). A derivation cohort and a validation cohort were randomly selected from available data. Clinical and laboratory manifestations associated with confirmed leptospirosis in the derivation cohort were selected for construction of a multivariate regression model with correlation matrices, and adjusted odds ratios were extracted for significant variables. The odds ratios thus derived were subsequently utilized in the criteria model, and sensitivity and specificity examined with ROC curves. A total of 592 patients were included in the final analysis with 450 (180 confirmed leptospirosis) in the derivation cohort and 142 (52 confirmed leptospirosis) in the validation cohort. The variables in the final model were: history of exposure to a possible source of leptospirosis (adjusted OR = 2.827; 95% CI = 1.517-5.435; p = 0.001) serum

  11. Improving a Lecture-Size Molecular Model Set by Repurposing Used Whiteboard Markers

    ERIC Educational Resources Information Center

    Dragojlovic, Veljko

    2015-01-01

    Preparation of an inexpensive model set from whiteboard markers and either HGS molecular model set or atoms made of wood is described. The model set is relatively easy to prepare and is sufficiently large to be suitable as an instructor set for use in lectures.

  12. Improving a Lecture-Size Molecular Model Set by Repurposing Used Whiteboard Markers

    ERIC Educational Resources Information Center

    Dragojlovic, Veljko

    2015-01-01

    Preparation of an inexpensive model set from whiteboard markers and either HGS molecular model set or atoms made of wood is described. The model set is relatively easy to prepare and is sufficiently large to be suitable as an instructor set for use in lectures.

  13. Multiple Brunhes Chron Excursions Recorded in the Eifel Volcanic Field

    NASA Astrophysics Data System (ADS)

    Singer, B. S.; Guillou, H.; Zhang, X.; Schnepp, E.; Hoffman, K. A.

    2006-12-01

    Volcanic records of excursional geomagnetic field behavior, in particular paleointensity estimates, are fragmentary for the Pleistocene. The West Eifel volcanic field is unique in that 12 of 66 measured lava flow sites record Virtual Geomagnetic Poles (VGPs) clustered between 34 to 45° N and 30 to 50° E (over Iraq). Paleointensities of 37 lavas reveal that 9 transitionally magnetized and four normally magnetized lavas are <30 μT and have VADMs < 3.8 x 10^{22} Am2 [Schnepp and Hradetzky, 1994; JGR]. Until now, the ages of these lava flows have been known only from imprecise 40Ar/39Ar data that implied acquisition of magnetic remanence between about 460 and 660 ka. Thus, they have been interpreted to record a single, but poorly defined, excursion. To incorporate these paleofield data into the global high-resolution Geomagnetic Instability Time Scale (GITS), we have determined precise ages of groundmass from 11 transitionally magnetized lava flows using the 40Ar/39Ar incremental heating method. New unspiked K-Ar age determinations from two samples are indistinguishable from their 40Ar/39Ar ages. The age determinations fall into five groups at 722 ± 38, 626 ± 24, 578 ± 8, 555 ± 4, and 528 ±16 ka (2σ analytical uncertainties, relative to 1.194 Ma Alder Creek sanidine). The group of 4 flows with an age of 578 ±8 ka correspond in age with lava flow sequences on Tahiti and La Palma that record the Big Lost excursion at 579 ±6 ka. The six other lavas erupted from 626 ka onward correlate with a group of second-order paleointensity lows in SINT-800 centered on the broad low during which the Big Lost excursion occurred. These lava flows thus record snapshots of the behavior of the total vector field experienced at this site during one of the most complex periods of geodynamo instability of the Brunhes Chron. Our findings suggest that four temporally distinctive excursions are recorded between 626 and 528 ka and that each weakening of the geodynamo during this period

  14. First-excursion probability in non-stationary random vibration.

    NASA Technical Reports Server (NTRS)

    Yang, J.-N.

    1973-01-01

    The first-excursion probability of a non-stationary Gaussian process with zero mean has been studied. Within the framework of the point process approach, a variety of analytical approximations applicable to stationary random processes is extended herein to non-stationary random processes. The extension is possible owing to a recent definition of non-stationary envelope processes proposed by the author. With the aid of numerical examples, merits of each approximation are examined by comparing with the results of simulation. It is found that under non-stationary excitations with short duration, the Markov approximation is the best among all the approximations discussed in this paper.

  15. An excursion approach to maxima of the Brownian bridge.

    PubMed

    Perman, Mihael; Wellner, Jon A

    2014-09-01

    Distributions of functionals of Brownian bridge arise as limiting distributions in non-parametric statistics. In this paper we will give a derivation of distributions of extrema of the Brownian bridge based on excursion theory for Brownian motion. The idea of rescaling and conditioning on the local time has been used widely in the literature. In this paper it is used to give a unified derivation of a number of known distributions, and a few new ones. Particular cases of calculations include the distribution of the Kolmogorov-Smirnov statistic and the Kuiper statistic.

  16. An excursion approach to maxima of the Brownian bridge

    PubMed Central

    Perman, Mihael; Wellner, Jon A.

    2016-01-01

    Distributions of functionals of Brownian bridge arise as limiting distributions in non-parametric statistics. In this paper we will give a derivation of distributions of extrema of the Brownian bridge based on excursion theory for Brownian motion. The idea of rescaling and conditioning on the local time has been used widely in the literature. In this paper it is used to give a unified derivation of a number of known distributions, and a few new ones. Particular cases of calculations include the distribution of the Kolmogorov-Smirnov statistic and the Kuiper statistic. PMID:27134338

  17. Possible record of the Laschamp Excursion in lacustrine sediments in the Searles Valley, California

    NASA Astrophysics Data System (ADS)

    Liddicoat, J.; Coe, R.; Knott, J.

    2009-04-01

    The Pleistocene history of Searles Lake, California, is known in detail from field work and cores recovered during industrial exploration of Searles Valley, in which the lake formed (Smith et al., 1979; Liddicoat et al., 1980). Exposed siltstone assigned the age about 34,000 to 46,000 calendar years B.P. (eight AMS 14-Carbon dates on gastropods and mollusks from fine- to medium-grain sand units that bracket the siltstone) records reverse palaeomagnetic polarity following thermal demagnetization to 600˚ C at two localities 3 km apart. For 12 samples (six pairs from six horizons, three pairs from each locality), the mean palaeomagnetic directions are Incl = - 37.5˚, Decl = 180.2˚, alpha 95 = 19.5˚ and the mean Virtual Geomagnetic Pole (VGP) is 73.6˚ S, 231.8˚ E, Alpha 95 = 20.6˚. The reverse polarity is not part of the Mono Lake Excursion (Denham and Cox, 1971) that never has a VGP in the Southern Hemisphere (Liddicoat and Coe, 1979). Other samples from the two Searles Valley localities do not reach a definite reverse direction but contain a component of magnetization that approaches reverse polarity above 400˚ C. The reverse polarity in Searles Lake sediments offers an opportunity to model the geomagnetic field for two excursions (Laschamp and Mono Lake) in western North America at localities separated by about 300 km.

  18. Eyelid reanimation with gold weight implant and tendon sling suspension: evaluation of excursion and velocity using the FACIAL CLIMA system.

    PubMed

    Hontanilla, Bernardo; Marre, Diego

    2013-04-01

    This study aims to analyse the efficacy of static techniques, namely gold weight implant and tendon sling, in the reanimation of the paralytic eyelid. Upper eyelid rehabilitation in terms of excursion and blinking velocity is performed using the automatic motion capture system, FACIAL CLIMA. Seventy-four patients underwent a total of 101 procedures including 58 upper eyelid gold weight implants and 43 lower eyelid tendon suspension with 27 patients undergoing both procedures. The presence of lagophtalmos, eye dryness, corneal ulcer, epiphora and lower lid ptosis/ectropion was assessed preoperatively. The Wilcoxon signed-rank test was used to compare preoperative versus postoperative measurements of upper eyelid excursion and blinking velocity determined with FACIAL CLIMA. Significance was set at p <0.05. FACIAL CLIMA revealed significant improvement of eyelid excursion and velocity of blinking (p < 0.001). Eye dryness improved in 49 patients (90.7%) and corneal ulcer resolved without any further treatment in 12 (85.7%) of those with a gold weight inserted. Implant extrusion was observed in 8.6% of the cases. Of the patients with lower lid tendon suspension, correction of ptosis/ectropion and epiphora was achieved in 93.9% and 91.9% of cases, respectively. In eight patients (18.6%), further surgery was needed to adjust tendon tension. The paralytic upper and lower eyelid can be successfully managed with gold weight implant and tendon suspension. The FACIAL CLIMA system is a reliable method to quantify upper eyelid excursion and blinking velocity and to detect the exact position of the lower eyelid. Copyright © 2012 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Geolab in NASA's First Generation Pressurized Excursion Module: Operational Concepts

    NASA Technical Reports Server (NTRS)

    Evans, C. A.; Bell, M. S.; Calway, M. J.

    2010-01-01

    We are building a prototype laboratory for preliminary examination of geological samples to be integrated into a first generation Habitat Demonstration Unit-1/Pressurized Excursion Module (HDU1-PEM) in 2010. The laboratory GeoLab will be equipped with a glovebox for handling samples, and a suite of instruments for collecting preliminary data to help characterize those samples. The GeoLab and the HDU1-PEM will be tested for the first time as part of the 2010 Desert Research and Technology Studies (DRATS), NASAs annual field exercise designed to test analog mission technologies. The HDU1-PEM and GeoLab will participate in joint operations in northern Arizona with two Lunar Electric Rovers (LER) and the DRATS science team. Historically, science participation in DRATS exercises has supported the technology demonstrations with geological traverse activities that are consistent with preliminary concepts for lunar surface science Extravehicular Activities (EVAs). Next years HDU1-PEM demonstration is a starting point to guide the development of requirements for the Lunar Surface Systems Program and test initial operational concepts for an early lunar excursion habitat that would follow geological traverses along with the LER. For the GeoLab, these objectives are specifically applied to enable future geological surface science activities. The goal of our GeoLab is to enhance geological science returns with the infrastructure that supports preliminary examination, early analytical characterization of key samples, insight into special considerations for curation, and data for prioritization of lunar samples for return to Earth.

  20. Comparison of Diaphragmatic Breathing Exercise, Volume and Flow Incentive Spirometry, on Diaphragm Excursion and Pulmonary Function in Patients Undergoing Laparoscopic Surgery: A Randomized Controlled Trial

    PubMed Central

    Anand, R.

    2016-01-01

    Objective. To evaluate the effects of diaphragmatic breathing exercises and flow and volume-oriented incentive spirometry on pulmonary function and diaphragm excursion in patients undergoing laparoscopic abdominal surgery. Methodology. We selected 260 patients posted for laparoscopic abdominal surgery and they were block randomization as follows: 65 patients performed diaphragmatic breathing exercises, 65 patients performed flow incentive spirometry, 65 patients performed volume incentive spirometry, and 65 patients participated as a control group. All of them underwent evaluation of pulmonary function with measurement of Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), Peak Expiratory Flow Rate (PEFR), and diaphragm excursion measurement by ultrasonography before the operation and on the first and second postoperative days. With the level of significance set at p < 0.05. Results. Pulmonary function and diaphragm excursion showed a significant decrease on the first postoperative day in all four groups (p < 0.001) but was evident more in the control group than in the experimental groups. On the second postoperative day pulmonary function (Forced Vital Capacity) and diaphragm excursion were found to be better preserved in volume incentive spirometry and diaphragmatic breathing exercise group than in the flow incentive spirometry group and the control group. Pulmonary function (Forced Vital Capacity) and diaphragm excursion showed statistically significant differences between volume incentive spirometry and diaphragmatic breathing exercise group (p < 0.05) as compared to that flow incentive spirometry group and the control group. Conclusion. Volume incentive spirometry and diaphragmatic breathing exercise can be recommended as an intervention for all patients pre- and postoperatively, over flow-oriented incentive spirometry for the generation and sustenance of pulmonary function and diaphragm excursion in the management of laparoscopic

  1. Using Set Covering with Item Sampling to Analyze the Infeasibility of Linear Programming Test Assembly Models

    ERIC Educational Resources Information Center

    Huitzing, Hiddo A.

    2004-01-01

    This article shows how set covering with item sampling (SCIS) methods can be used in the analysis and preanalysis of linear programming models for test assembly (LPTA). LPTA models can construct tests, fulfilling a set of constraints set by the test assembler. Sometimes, no solution to the LPTA model exists. The model is then said to be…

  2. Upward excursion limits from air saturation at 5 ATA (Atmospheres Absolute)

    NASA Astrophysics Data System (ADS)

    Parker, James W.

    1989-01-01

    Present USN submarine rescue capability makes a prolonged exposure of the submarine crew to hyperbaric air a distinct possibility. The exposure may be to pressures as great as 5 atmospheres absolute (ATA), and for periods of time of up to 72 hours. A series of experimental dives were conducted to establish the safe, upward excursion from 5 ATA (132 FSWG); that is, the maximum, immediate reduction in pressure which these individuals can safely tolerate. This specifies the required pressure in the compartment of a mother submarine to which the rescued personnel would be transferred. In order to minimize the effects of pulmonary oxygen toxicity, the limits first were established using a nitrox equivalent of air at 5 ATA. The upward limit from 4.36 ATA (111 FSWG) was found to be 2.97 ATA (65 FSWG). Once this limit had been set, a series of dives were conducted to test this up limit from standard air at 5 ATA.

  3. Morphology of the Iceland Basin Excursion from a spherical harmonics analysis and an iterative Bayesian inversion procedure of sedimentary records

    NASA Astrophysics Data System (ADS)

    Lanci, Luca; Kissel, Catherine; Leonhardt, Roman; Laj, Carlo

    2008-08-01

    Based on 5 published marine high-resolution sedimentary records of the Iceland Basin Excursion [IBE; Channell, J.E.T., Hodell, D.A., Lehman, B., 1997. Relative geomagnetic paleointensity and ∂ 18O at ODP Site 983/Gardar Drift, North Atlantic since 350 ka. Earth Planet. Sci. Lett. 153, 103-118; Laj, C., Kissel, C., Roberts, A., 2006. Geomagnetic field behavior during the Iceland Basin and Laschamp geomagnetic excursions: a simple transitional field geometry? Geochem. Geophys. Geosystems. 7, Q03004, doi:10.1029/2005GC001122] dated around 186-190 kyr, we present models of the excursional geomagnetic field at the Earth's surface using two different approaches. First a spherical harmonics analysis is performed after synchronization of the records using their paleointensity profiles. Second, we have used an iterative Bayesian inversion procedure, calibrated using the single volcanic data available so far. Both modeling approaches suffer from imperfections of the paleomagnetic signals and mostly from the still poor geographical distribution of detailed records, presently available only from the North Atlantic and the West Pacific. For these reasons, our modeling results should only be regarded as preliminary models of the geomagnetic field during the IBE, susceptible to improvements when including results from future paleomagnetic studies. Nevertheless, both approaches show distinct similarities and are stable against moderate variations of modeling parameters. The general picture is that of a dipole field undergoing a strong reduction, but remaining higher than the non-dipole field all through the excursional process, except for a very short interval of time corresponding to the dipole minimum at the center of the excursion. On the other hand, some differences exist between the results of the two models with each other and with the real data when the virtual geomagnetic pole (VGP) paths are considered. The non-dipole field does not appear to undergo very significant

  4. Setting, Evaluating, and Maintaining Certification Standards with the Rasch Model.

    ERIC Educational Resources Information Center

    Grosse, Martin E.; Wright, Benjamin D.

    1986-01-01

    Based on the standard setting procedures or the American Board of Preventive Medicine for their Core Test, this article describes how Rasch measurement can facilitate using test content judgments in setting a standard. Rasch measurement can then be used to evaluate and improve the precision of the standard and to hold it constant across time.…

  5. Models of Music Therapy Intervention in School Settings

    ERIC Educational Resources Information Center

    Wilson, Brian L., Ed.

    2002-01-01

    This completely revised 2nd edition edited by Brian L. Wilson, addresses both theoretical issues and practical applications of music therapy in educational settings. 17 chapters written by a variety of authors, each dealing with a different setting or issue. A valuable resource for demonstrating the efficacy of music therapy to school…

  6. Setting, Evaluating, and Maintaining Certification Standards with the Rasch Model.

    ERIC Educational Resources Information Center

    Grosse, Martin E.; Wright, Benjamin D.

    1986-01-01

    Based on the standard setting procedures or the American Board of Preventive Medicine for their Core Test, this article describes how Rasch measurement can facilitate using test content judgments in setting a standard. Rasch measurement can then be used to evaluate and improve the precision of the standard and to hold it constant across time.…

  7. Models of Music Therapy Intervention in School Settings

    ERIC Educational Resources Information Center

    Wilson, Brian L., Ed.

    2002-01-01

    This completely revised 2nd edition edited by Brian L. Wilson, addresses both theoretical issues and practical applications of music therapy in educational settings. 17 chapters written by a variety of authors, each dealing with a different setting or issue. A valuable resource for demonstrating the efficacy of music therapy to school…

  8. Bayesian model comparison in genetic association analysis: linear mixed modeling and SNP set testing.

    PubMed

    Wen, Xiaoquan

    2015-10-01

    We consider the problems of hypothesis testing and model comparison under a flexible Bayesian linear regression model whose formulation is closely connected with the linear mixed effect model and the parametric models for Single Nucleotide Polymorphism (SNP) set analysis in genetic association studies. We derive a class of analytic approximate Bayes factors and illustrate their connections with a variety of frequentist test statistics, including the Wald statistic and the variance component score statistic. Taking advantage of Bayesian model averaging and hierarchical modeling, we demonstrate some distinct advantages and flexibilities in the approaches utilizing the derived Bayes factors in the context of genetic association studies. We demonstrate our proposed methods using real or simulated numerical examples in applications of single SNP association testing, multi-locus fine-mapping and SNP set association testing. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Geomagnetic Estimates of the Mean Rates of Paleomagnetic Dipole Power Excursions and Reversals

    NASA Astrophysics Data System (ADS)

    Voorhies, C. V.

    2007-12-01

    To further and better test some kinematic, dynamical, and statistical hypotheses about the core geodynamo, previous predictions for the mean rates and durations of dipole power excursions and axial dipole reversals [Voorhies & Conrad, 1996] are re-examined and refined. The hypotheses yield a theoretical form for the low degree, core-source part of the Lowes-Mauersberger spectrum R(n) - the mean square field, averaged over the sphere of radius a, in spherical harmonics of degree n. This form is \\{R(n)\\} = K[(n + 1/2)/n(n + 1)](c/a)**(2n+4); core radius c = 3.5 +/- 0.1 Mm is recovered with no significant error by fitting log-theoretical to log-observational spectra for Earth [Voorhies, 2004]. Jupiter may also have a "1/n" spectrum, but Mercury's field seems too weak and for its core dynamo to be very Earth-like. Our statistical hypothesis distributes (2n+1)R(n)/\\{R(n)\\} as chi-square with 2n+1 degrees of freedom. The implied field is usually mainly dipolar and can be primarily axial. During a small fraction of geologic time, however, dipole power R(1) is expected to be quite small. An unusually weak axial dipole might reverse during such an interval. So we defined "dipole power excursion" as an interval when absolute dipole moment is less than or equal to a threshold value, taken to be the absolute equatorial dipole moment at 1980. Our amplitude estimate implied that such excursions would occupy 2.5% of geologic time. We used the 1945-1980 dipole power time scale to convert this fraction into mean duration, hence mean rate. For dipole power excursions, we predicted a mean duration of 2767 years and a mean rate of 9.04 per million years; for reversals, we predicted a mean duration of 5534 years and a mean rate of 2.26 per million years [Voorhies & Conrad, 1996]. The method and results are critically reviewed and updated, with special attention to definitions, calibration, time scale, the one quarter rule for reversal/excursion rates, and uncertainty estimates. For

  10. Does rational selection of training and test sets improve the outcome of QSAR modeling?

    PubMed

    Martin, Todd M; Harten, Paul; Young, Douglas M; Muratov, Eugene N; Golbraikh, Alexander; Zhu, Hao; Tropsha, Alexander

    2012-10-22

    Prior to using a quantitative structure activity relationship (QSAR) model for external predictions, its predictive power should be established and validated. In the absence of a true external data set, the best way to validate the predictive ability of a model is to perform its statistical external validation. In statistical external validation, the overall data set is divided into training and test sets. Commonly, this splitting is performed using random division. Rational splitting methods can divide data sets into training and test sets in an intelligent fashion. The purpose of this study was to determine whether rational division methods lead to more predictive models compared to random division. A special data splitting procedure was used to facilitate the comparison between random and rational division methods. For each toxicity end point, the overall data set was divided into a modeling set (80% of the overall set) and an external evaluation set (20% of the overall set) using random division. The modeling set was then subdivided into a training set (80% of the modeling set) and a test set (20% of the modeling set) using rational division methods and by using random division. The Kennard-Stone, minimal test set dissimilarity, and sphere exclusion algorithms were used as the rational division methods. The hierarchical clustering, random forest, and k-nearest neighbor (kNN) methods were used to develop QSAR models based on the training sets. For kNN QSAR, multiple training and test sets were generated, and multiple QSAR models were built. The results of this study indicate that models based on rational division methods generate better statistical results for the test sets than models based on random division, but the predictive power of both types of models are comparable.

  11. High-resolution palaeomagnetic records of the Laschamp geomagnetic excursion from ODP Sites 1061 and 1062

    NASA Astrophysics Data System (ADS)

    Bourne, M. D.; Henderson, G. M.; Thomas, A. L.; Mac Niocaill, C.

    2012-12-01

    The Laschamp geomagnetic excursion (~41 ka) was a brief global deviation in geomagnetic field behaviour from that expected during normal secular variation. Previously published records suggest rapid changes in field direction and a concurrent substantial decrease in field intensity. We present here high-resolution palaeomagnetic records of the Laschamp excursion obtained from two Ocean Drilling Program (ODP) Sites 1061 and 1062 on the Blake-Bahama Outer Ridge (ODP Leg 172) and compare this record with previously published records of the Blake and Iceland Basin Excursions. Relatively high sedimentation rates (>10 cm kyr-1) at these locations allow the determination of transitional field behaviour during the excursion. Rather than assuming a constant sedimentation rate between assigned age tie-points, we employ measurements of 230Thxs concentration in the sediment to assess variations in the sedimentation rates through the core sections of interest. This allows us to better determine the temporal behaviour of the Laschamp excursion with greater accuracy and known uncertainty. The Laschamp excursion at this location appears to be much shorter in duration than the Blake and Iceland Basin excursions. Palaeomagnetic measurements of discrete samples from four cores reveal a single excursional feature, across an interval of 30 cm, associated with a broader palaeointensity low. The excursion is characterised by rapid transitions (less than 500 years) between a stable normal polarity and a partially-reversed, polarity. Peaks in inclination either side of the directional excursion indicate periods of time when the local field is dominated by vertical flux patches. Similar behaviour has been observed in records of the Iceland Basin Excursion from the same region. The palaeointensity record is in good agreement between the two sites. The palaeointensity record shows two minima, where the second dip in intensity is associated with a more limited directional deviation. Similar

  12. Polarity and Excursion Transitions: Can they be Adequately Recorded in High-Sedimentation-Rate Marine Sediments?

    NASA Astrophysics Data System (ADS)

    Channell, J. E. T.

    2014-12-01

    Polarity transitions and magnetic excursions have durations of a few thousand years, or less. Transition/excursion records in volcanic sequences are, at best, partial snap-shots of the transition/excursion field. Records from high-sedimentation-rate marine sediments may be more continuous but they are always smoothed by progressive acquisition of detrital remanent magnetization (DRM), and by sampling/measurement limitations. North Atlantic records of the Matuyama-Brunhes (M-B) polarity transition are compared with records of the Iceland Basin excursion (190 ka). Virtual geomagnetic polar (VGP) paths are used to map characteristic magnetization directions during the transition/excursion. Relative paleointensity (RPI) proxies indicate partial recovery of field intensity during the transition/excursion, with RPI minima coinciding with abrupt VGP shifts at the onset and end of the transition/excursion. Discrepancies in VGP paths among holes at the same site, among sites, and a comparison of u-channel and discrete sample measurements, reveal limitations in resolution of the transition/excursion fields. During the M-B polarity transition, VGP clusters appear in the NW Pacific, NE Asia and in the South Atlantic. Similarities in VGP clustering for the M-B boundary and the Iceland Basin excursion imply that the polarity transition and excursion fields had common characteristics. Similarities with the modern non-axial dipole (NAD) field imply that polarity transitions and excursions involve the demise of the Earth's axial dipole relative to the NAD field, and that the NAD field has long-lasting features locked in place by the lowermost mantle.

  13. A Move to an Innovative Games Teaching Model: Style E Tactical (SET)

    ERIC Educational Resources Information Center

    Nathan, Sanmuga; Haynes, John

    2013-01-01

    This paper reports on the development and testing of a hybrid model of teaching games--The Style "E" Tactical (SET) Model. The SET is a combination of two pedagogical approaches: Mosston and Ashworth's Teaching Styles and Bunker and Thorpe's Teaching Games for Understanding (TGfU). To test the efficacy of this new model, the SET was…

  14. A Move to an Innovative Games Teaching Model: Style E Tactical (SET)

    ERIC Educational Resources Information Center

    Nathan, Sanmuga; Haynes, John

    2013-01-01

    This paper reports on the development and testing of a hybrid model of teaching games--The Style "E" Tactical (SET) Model. The SET is a combination of two pedagogical approaches: Mosston and Ashworth's Teaching Styles and Bunker and Thorpe's Teaching Games for Understanding (TGfU). To test the efficacy of this new model, the SET was…

  15. Multiple High-Frequency Carbon Isotope Excursions Across the Precambrian-Cambrian Boundary: Implications for Correlations and Environmental Change

    NASA Astrophysics Data System (ADS)

    Smith, E. F.; Macdonald, F. A.; Schrag, D. P.; Laakso, T.

    2014-12-01

    The GSSP Precambrian-Cambrian boundary in Newfoundland is defined by the first appearance datum (FAD) of Treptichnus pedum, which is considered to be roughly coincident with the FAD of small shelly fossils (SSFs) and a large negative carbon isotope excursion. An association between the FAD of T. pedum and a negative carbon isotope excursion has previously been documented in Northwest Canada (Narbonne et al., 1994) and Death Valley (Corsetti and Hagadorn, 2000), and since then has been used as an chronostratigraphic marker of the boundary, particularly in siliciclastic poor sections that do not preserve T. pedum. Here we present new high-resolution carbon isotope (δ13C ) chemostratigraphy from multiple sections in western Mongolia and the western United States that span the Ediacaran-Cambrian transition. High-resolution sampling (0.2-1 m) reveals that instead of one large negative excursion, there are multiple, high-frequency negative excursions with an overall negative trend during the latest Ediacaran. These data help to more precisely calibrate changes in the carbon cycle across the boundary as well as to highlight the potential problem of identifying the boundary with just a few negative δ13C values. We then use a simple carbon isotope box model to explore relationships between phosphorous delivery to the ocean, oxygenation, alkalinity, and turnovers in carbonate secreting organisms. Corsetti, F.A., and Hagadorn, J.W., 2000, Precambrian-Cambrian transition: Death Valley, United States: Geology, v. 28, no. 4, p. 299-302. Narbonne, G.M., Kaufman, A.J., and Knoll, A.H., 1994, Integrated chemostratigraphy and biostratigraphy of the Windermere Supergroup, northwestern Canada: Implications for Neoproterozoic correlations and the early evolution of animals: Geological Society of America Bulletin, v. 106, no. 10, p. 1281-1292.

  16. The Earth climate and life evolution response to cosmic radiation enhancement arising from reversals and excursions of geomagnetic field

    NASA Astrophysics Data System (ADS)

    Kuznetsova, N.

    Climate abrupt warming as well as biologic evolutionary events in respect to fauna and human evolution are shown to originate during reversals and excursions of geomagnetic field when the geomagnetic field loses a lot in its module value and consequently in its protective characteristics making galactic cosmic rays GCR and solar protons penetration into the Earth atmosphere possible Usually preceded by climate cooling and populations reduction reversals and excursions stimulate evolutionary genetic mutations generated by intense radiation and climate abrupt warming resulted from destruction of stratospheric aerosols by GCR Favorable environment conditions on new features and species origin For example it was Gauss-Matuyama reversal 2 3 Myr to make for Hominid evolutionary mutations and for distinctly new species Homo erectus origin The evolutionary events and climate shifts appear explicable on the context of the fundamentally new model of the geomagnetic field generation based on hypothesis of the hot Earth and the theory of the Earth magnetic poles drift throughout reversals and excursions theory

  17. Parameter set uniqueness and confidence limits in model identification of insulin transport models from simulation data.

    PubMed

    Farmer, Terry G; Edgar, Thomas F; Peppas, Nicholas A

    2008-04-01

    The use of patient models describing the dynamics of glucose, insulin, and possibly other metabolic species associated with glucose regulation allows diabetes researchers to gain insights regarding novel therapies via simulation. However, such models are only useful when model parameters are effectively estimated with patient data. The use of least squares to effectively estimate model parameters from simulation data was investigated by observing factors that influence the accuracy of estimates for the model parameters from a data set generated using a model with known parameters. An intravenous insulin pharmacokinetic model was used to generate the insulin response of a patient with type 1 diabetes mellitus to a series of step changes in the insulin infusion rate from an external insulin pump. The effects of using user-defined gradient and Hessian calculations on both parameter estimations and the 95% confidence limits of the estimated parameter sets were investigated. Estimations performed by either solver without user-supplied quantities were highly dependent on the initial guess of the parameter set, with relative confidence limits greater than +/-100%. The use of user-defined quantities allowed the one-compartment model parameters to be effectively estimated. While the two-compartment model parameter estimation still depended on the initial parameter set specification, confidence limits were decreased, and all fits to simulation data were very good. The use of user-defined gradients and Hessian matrices results in more accurate parameter estimations for insulin transport models. Improved estimation could result in more accurate simulations for use in glucose control system design.

  18. Dynamics of the earth magnetic field in the 10-75 kyr period comprising the Laschamp and Mono Lake excursions: New results from the French Chaîne des Puys in a global perspective

    NASA Astrophysics Data System (ADS)

    Laj, Carlo; Guillou, Hervé; Kissel, Catherine

    2014-02-01

    We report here on a new paleomagnetic (directions and intensities) and coupled K/Ar and 40Ar/39Ar analysis of 35 different flows, emplaced in the Chaîne des Puys during the 75 to 10 kyr interval, which contains the Mono Lake and Laschamp excursions. There is a remarkable agreement between the new set of absolute volcanic intensities and published sedimentary (GLOPIS-75) and cosmogenic (10Be and 36Cl) records. The Laschamp and Mono Lake excursions are clearly revealed by a very significant intensity drop at 41.2±1.6 ka and 34.2±1.2 ka respectively. The duration of the Laschamp excursion is ˜1500 yr and about 640 yr when the drop of paleointensity or the directional change are considered respectively. The intensity drop at the Mono Lake is twice as short. In the ˜7 ka interval separating the two excursions, the field intensity recovers to almost non-transitional values. The rate of decrease of the field intensity during these excursions attains 18 nT/yr for the Laschamp and even greater value (33 nT/yr) for the Mono Lake. This figure is, for the Laschamp excursion, similar to the present field intensity decrease in the last two centuries so that one may wonder whether such a high rate of change may be characteristic of an impending geomagnetic event (reversal or excursion). We suggest that the name Auckland excursion should be used for the present-day called Mono Lake.

  19. Geolab 2010 Hardware in NASA's Pressurized Excursion Module

    NASA Technical Reports Server (NTRS)

    Calaway, M. J.; Evans, C. A.; Bell, M. S.

    2010-01-01

    NASA is designing and building the Habitat Demonstration Unit - 1 in a Pressurized Excursion Module (HDU1- PEM) configuration for analog testing at NASA s annual Desert Research and Technology Studies (DRATS) near Flagstaff, Arizona in late summer 2010. The HDU1-PEM design is based on NASA Constellation program s Lunar Scenario 12.1 (nicknamed "Lunabago"). This scenario uses Lunar Electric Rovers (LER) and a PEM for long-distance lunar exploration. The 2010 HDU version 1.0 will be an unpressurized PEM that contains a GeoLab in one of the eight PEM sections. The GeoLab is designed to facilitate sample curation protocol development including such activities as preliminary examination, sample archiving, and high grading of astromaterials for return to Earth. Geolab operations will be integrated with the DRATS science traverses and operations.

  20. Redox State of the Deep Ocean During the 2.22-2.1 Ga Carbon Isotope Excursion

    NASA Astrophysics Data System (ADS)

    Bekker, A.; Shen, Y.; Scott, C.; Kacanda, M.; Lyons, T.; Kenig, F.; Anbar, A.; Rouxel, O.

    2006-05-01

    Response of the redox state of the deep ocean to the rise of atmospheric oxygen, as well as the 2.22-2.1 Ga carbon isotope excursion that followed, is not known. The c. 2.15 Ga Sengoma Argillite Formation (SAF), Botswana, is correlative with the Silverton Formation (SF), South Africa, which contains carbonates with δ °13°C values ranging from +8.3 to +11.3 ‰ PDB. Both units were deposited along the northern margin of the Kaapvaal Craton in an open-marine environment. The SAF consists of two upward- shallowing cycles with organic-rich sulfidic shales deposited in subtidal settings at the base and red beds deposited in coastal and fluvial settings at the top. Sulfur isotope data show a large range from -21.3 to +13.7 ‰ V-CDT with highly negative values confined to the lower part of the cycles and positive values to the upper part of the cycles. The Fe speciation data show similar stratigraphic trends. Carbon isotope values of organic matter are as low as -33.7 ‰ PDB, and if compared with carbonate carbon isotope record of the correlative SF, suggest significant contribution from secondary productivity via either sulfur or methane oxidation. Mo concentrations in these organic-rich shales are just above crustal levels. These data suggest deep ocean euxinic conditions during the carbon isotope excursion. Fe isotope data for sulfides from these shales show an unusually narrow range of Fe isotope values relative to other Archean and Paleoproterozoic sulfides. These data fall within the range of the hydrothermal iron flux, suggesting complete Fe reduction and precipitation as sulfide in the deep ocean. The 2.1-2.0 Ga Ludikovian black shales, Russia, were also deposited in an open marine and euxinic environment but contain much higher Mo levels up to 74 ppm and sulfides with Fe isotope values ranging from those of hydrothermal Fe flux to highly positive values. Higher Mo concentrations in these shales suggest that significant part of the ocean was not a sink for Mo

  1. Trunk-Rotation Differences at Maximal Reach of the Star Excursion Balance Test in Participants With Chronic Ankle Instability

    PubMed Central

    de la Motte, Sarah; Arnold, Brent L.; Ross, Scott E.

    2015-01-01

    Context: Functional reach on the Star Excursion Balance Test is decreased in participants with chronic ankle instability (CAI). However, comprehensive 3-dimensional kinematics associated with these deficits have not been reported. Objective: To determine if lower extremity kinematics differed in CAI participants during anteromedial, medial, and posteromedial reach on the Star Excursion Balance Test. Design: Case-control study. Setting: Sports medicine research laboratory. Patients or Other Participants: Twenty CAI participants (age = 24.15 ± 3.84 years, height = 168.95 ± 11.57 cm, mass = 68.95 ± 16.29 kg) and 20 uninjured participants (age = 25.65 ± 5.58 years, height = 170.14 ± 8.75 cm, mass = 69.89 ± 10.51 kg) with no history of ankle sprain. We operationally defined CAI as repeated episodes of ankle “giving way” or “rolling over” or both, regardless of neuromuscular deficits or pathologic laxity. All CAI participants scored ≤26 on the Cumberland Ankle Instability Tool. Intervention(s): Star Excursion Balance Test reaches in the anteromedial, medial, and posteromedial directions. The CAI participants used the unstable side as the stance leg. Control participants were sex, height, mass, and side matched to the CAI group. The 3-dimensional kinematics were assessed with a motion-capture system. Main Outcome Measure(s): Group differences on normalized reach distance, trunk, pelvis, and hip-, knee-, and ankle-joint angles at maximum Star Excursion Balance Test reach. Results: No reach-distance differences were detected between CAI and uninjured participants in any of the 3 reach directions. With anteromedial reach, trunk rotation (t1,38 = 3.06, P = .004), pelvic rotation (t1,38 = 3.17, P = .003), and hip flexion (t1,38 = 2.40, P = .002) were greater in CAI participants. With medial reach, trunk flexion (t1,38 = 6.39, P = .05) was greater than for uninjured participants. No differences were seen with posteromedial reach. Conclusions: We did not detect

  2. Modeling mania in preclinical settings: a comprehensive review

    PubMed Central

    Sharma, Ajaykumar N.; Fries, Gabriel R.; Galvez, Juan F.; Valvassori, Samira S.; Soares, Jair C.; Carvalho, André F.; Quevedo, Joao

    2015-01-01

    The current pathophysiological understanding of mechanisms leading to onset and progression of bipolar manic episodes remains limited. At the same time, available animal models for mania have limited face, construct, and predictive validities. Additionally, these models fail to encompass recent pathophysiological frameworks of bipolar disorder (BD), e.g. neuroprogression. Therefore, there is a need to search for novel preclinical models for mania that could comprehensively address these limitations. Herein we review the history, validity, and caveats of currently available animal models for mania. We also review new genetic models for mania, namely knockout mice for genes involved in neurotransmission, synapse formation, and intracellular signaling pathways. Furthermore, we review recent trends in preclinical models for mania that may aid in the comprehension of mechanisms underlying the neuroprogressive and recurring nature of BD. In conclusion, the validity of animal models for mania remains limited. Nevertheless, novel (e.g. genetic) animal models as well as adaptation of existing paradigms hold promise. PMID:26545487

  3. Physical property parameter set for modeling ICPP aqueous wastes with ASPEN electrolyte NRTL model

    SciTech Connect

    Schindler, R.E.

    1996-09-01

    The aqueous waste evaporators at the Idaho Chemical Processing Plant (ICPP) are being modeled using ASPEN software. The ASPEN software calculates chemical and vapor-liquid equilibria with activity coefficients calculated using the electrolyte Non-Random Two Liquid (NRTL) model for local excess Gibbs free energies of interactions between ions and molecules in solution. The use of the electrolyte NRTL model requires the determination of empirical parameters for the excess Gibbs free energies of the interactions between species in solution. This report covers the development of a set parameters, from literature data, for the use of the electrolyte NRTL model with the major solutes in the ICPP aqueous wastes.

  4. Modeling wildland fire propagation with level set methods

    Treesearch

    V. Mallet; D.E Keyes; F.E. Fendell

    2009-01-01

    Level set methods are versatile and extensible techniques for general front tracking problems, including the practically important problem of predicting the advance of a fire front across expanses of surface vegetation. Given a rule, empirical or otherwise, to specify the rate of advance of an infinitesimal segment of fire front arc normal to itself (i.e., given the...

  5. Attachment Disorders: A Proposed Model for the School Setting.

    ERIC Educational Resources Information Center

    Parker, Kandis Cooke

    This paper explores the literature on attachment disorders in order to discover if the school setting can be an appropriate treatment option for children with mild attachment disorders, and in order to investigate how counselors can implement this treatment option. The introduction discusses the effects of recent changes in family structure on…

  6. Judgmental Standard Setting Using a Cognitive Components Model.

    ERIC Educational Resources Information Center

    McGinty, Dixie; Neel, John H.

    A new standard setting approach is introduced, called the cognitive components approach. Like the Angoff method, the cognitive components method generates minimum pass levels (MPLs) for each item. In both approaches, the item MPLs are summed for each judge, then averaged across judges to yield the standard. In the cognitive components approach,…

  7. Attachment Disorders: A Proposed Model for the School Setting.

    ERIC Educational Resources Information Center

    Parker, Kandis Cooke

    This paper explores the literature on attachment disorders in order to discover if the school setting can be an appropriate treatment option for children with mild attachment disorders, and in order to investigate how counselors can implement this treatment option. The introduction discusses the effects of recent changes in family structure on…

  8. Multivariate gene-set testing based on graphical models.

    PubMed

    Städler, Nicolas; Mukherjee, Sach

    2015-01-01

    The identification of predefined groups of genes ("gene-sets") which are differentially expressed between two conditions ("gene-set analysis", or GSA) is a very popular analysis in bioinformatics. GSA incorporates biological knowledge by aggregating over genes that are believed to be functionally related. This can enhance statistical power over analyses that consider only one gene at a time. However, currently available GSA approaches are based on univariate two-sample comparison of single genes. This means that they cannot test for multivariate hypotheses such as differences in covariance structure between the two conditions. Yet interplay between genes is a central aspect of biological investigation and it is likely that such interplay may differ between conditions. This paper proposes a novel approach for gene-set analysis that allows for truly multivariate hypotheses, in particular differences in gene-gene networks between conditions. Testing hypotheses concerning networks is challenging due the nature of the underlying estimation problem. Our starting point is a recent, general approach for high-dimensional two-sample testing. We refine the approach and show how it can be used to perform multivariate, network-based gene-set testing. We validate the approach in simulated examples and show results using high-throughput data from several studies in cancer biology. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Linear and Nonlinear Models of Agenda Setting in Television.

    ERIC Educational Resources Information Center

    Brosius, Hans-Bernd; Kepplinger, Hans Mathias

    1992-01-01

    A content analysis of major German television news shows and 53 weekly surveys on 16 issues were used to compare linear and nonlinear models as ways to describe the relationship between media coverage and the public agenda. Results indicate that nonlinear models are in some cases superior to linear models in terms of explained variance. (34…

  10. Place-Responsive Pedagogy: Learning from Teachers' Experiences of Excursions in Nature

    ERIC Educational Resources Information Center

    Mannion, Greg; Fenwick, Ashley; Lynch, Jonathan

    2013-01-01

    The nature-based excursion has been a significant teaching strategy in environmental education for decades. This article draws upon empirical data from a collaborative research project where teachers were encouraged to visit natural areas to provide an understanding of their roles and experiences of planning and enacting excursions. The analysis…

  11. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Ferries, excursion boats and other vessels. 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL AND... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and other vessels. ...

  12. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Ferries, excursion boats and other vessels. 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL AND... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and other vessels. ...

  13. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Ferries, excursion boats and other vessels. 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL AND... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and other vessels. ...

  14. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 1 2012-10-01 2012-10-01 false Ferries, excursion boats and other vessels. 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT... Ferries, excursion boats and other vessels. ...

  15. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 1 2014-10-01 2014-10-01 false Ferries, excursion boats and other vessels. 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT... Ferries, excursion boats and other vessels. ...

  16. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  17. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 1 2013-10-01 2013-10-01 false Ferries, excursion boats and other vessels. 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT... Ferries, excursion boats and other vessels. ...

  18. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  19. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  20. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  1. 46 CFR 72.25-15 - Passenger accommodations for excursion boats, ferryboats, and passenger barges.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Passenger accommodations for excursion boats, ferryboats, and passenger barges. 72.25-15 Section 72.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY... accommodations for excursion boats, ferryboats, and passenger barges. (a) Except as specifically excluded by this...

  2. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 1 2011-10-01 2011-10-01 false Ferries, excursion boats and other vessels. 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT... Ferries, excursion boats and other vessels. ...

  3. 36 CFR § 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Ferries, excursion boats and other vessels. [Reserved] § 1192.177 Section § 1192.177 Parks, Forests, and Public Property... GUIDELINES FOR TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and...

  4. 49 CFR 38.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Ferries, excursion boats and other vessels. 38.177 Section 38.177 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT... Ferries, excursion boats and other vessels. ...

  5. 36 CFR 1192.177 - Ferries, excursion boats and other vessels. [Reserved

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Ferries, excursion boats and other vessels. 1192.177 Section 1192.177 Parks, Forests, and Public Property ARCHITECTURAL AND... TRANSPORTATION VEHICLES Other Vehicles and Systems § 1192.177 Ferries, excursion boats and other vessels. ...

  6. Place-Responsive Pedagogy: Learning from Teachers' Experiences of Excursions in Nature

    ERIC Educational Resources Information Center

    Mannion, Greg; Fenwick, Ashley; Lynch, Jonathan

    2013-01-01

    The nature-based excursion has been a significant teaching strategy in environmental education for decades. This article draws upon empirical data from a collaborative research project where teachers were encouraged to visit natural areas to provide an understanding of their roles and experiences of planning and enacting excursions. The analysis…

  7. Geomagnetic Excursions: A Critical Assessment of the Evidence as Recorded in Sediments of the Brunhes Epoch

    NASA Astrophysics Data System (ADS)

    Verosub, K. L.

    1982-08-01

    Geomagnetic excursions have tantalized geophysicists since the earliest suggestion of their occurrence over 15 years ago. Either as large-scale geomagnetic secular variation, geomagnetic reversals of short duration or aborted reversals, they held great promise of providing new insights into the nature of the origin of the geomagnetic field. Unfortunately the evidence for geomagnetic excursions from the palaeomagnetic record of Brunhes age sediments is not as compelling as the theoretical arguments. A critical assessment of the available data indicates that the Gothenburg excursion is unlikely to have occurred and the Erieau excursion is very unlikely. The Mono Lake excursion probably occurred, but its absence in nearby contemporaneous sites creates profound problems. The Blake Event appears to be an actual short reversal of complex character, but confirmation of its global nature may be quite difficult.

  8. Ca and Mg isotope constraints on the origin of Earth's deepest δ13 C excursion

    NASA Astrophysics Data System (ADS)

    Husson, Jon M.; Higgins, John A.; Maloof, Adam C.; Schoene, Blair

    2015-07-01

    Understanding the extreme carbon isotope excursions found in carbonate rocks of the Ediacaran Period (635-541 Ma), where δ13 C of marine carbonates (δ13 Ccarb) reach their minimum (- 12 ‰) for Earth history, is one of the most vexing problems in Precambrian geology. Known colloquially as the 'Shuram' excursion, the event has been interpreted by many as a product of a profoundly different Ediacaran carbon cycle. More recently, diagenetic processes have been invoked, with the very negative δ13 C values of Ediacaran carbonates explained via meteoric alteration, late-stage burial diagenesis or growth of authigenic carbonates in the sediment column, thus challenging models which rely upon a dramatically changing redox state of the Ediacaran oceans. Here we present 257 δ 44 / 40 Ca and 131 δ26 Mg measurements, along with [Mg], [Mn] and [Sr] data, from carbonates of the Ediacaran-aged Wonoka Formation (Fm.) of South Australia to bring new isotope systems to bear on understanding the 'Shuram' excursion. Data from four measured sections spanning the basin reveal stratigraphically coherent trends, with variability of ∼1.5‰ in δ26 Mg and ∼1.2‰ in δ 44 / 40 Ca. This Ca isotope variability dwarfs the 0.2-0.3 ‰ change seen coeval with the Permian-Triassic mass extinction, the largest recorded in the rock record, and is on par with putative changes in the δ 44 / 40 Ca value of seawater seen over the Phanerozoic Eon. Changes in both isotopic systems are too large to explain with changes in the isotopic composition of Ca and Mg in global seawater given modern budgets and residence times, and thus must be products of alternative processes. Relationships between δ 44 / 40 Ca and [Sr] and δ26 Mg and [Mg] are consistent with mineralogical control (e.g., aragonite vs. calcite, limestone vs. dolostone) on calcium and magnesium isotope variability. The most pristine samples in the Wonoka dataset, preserving Sr concentrations (in the 1000s of ppm range) and δ 44 / 40

  9. Mathematical modeling of forest fire initiation in three dimensional setting

    Treesearch

    Valeriy Perminov

    2007-01-01

    In this study, the assignment and theoretical investigations of the problems of forest fire initiation were carried out, including development of a mathematical model for description of heat and mass transfer processes in overterrestrial layer of atmosphere at crown forest fire initiation, taking into account their mutual influence. Mathematical model of forest fire...

  10. Using behavior modeling for supervisory development in health care settings.

    PubMed

    Decker, P J; Sullivan, E; Moore, R

    1982-01-01

    Behavior modeling is one training method found effective in helping health care managers deal with their day-to-day management problems. This article defines and explains the five basic steps of behavior modeling training, suggests the workshop format as its most effective mode of instruction, and presents examples of successful use of the method.

  11. Modeling a set of heavy oil aqueous pyrolysis experiments

    SciTech Connect

    Thorsness, C.B.; Reynolds, J.G.

    1996-11-01

    Aqueous pyrolysis experiments, aimed at mild upgrading of heavy oil, were analyzed using various computer models. The primary focus of the analysis was the pressure history of the closed autoclave reactors obtained during the heating of the autoclave to desired reaction temperatures. The models used included a means of estimating nonideal behavior of primary components with regard to vapor liquid equilibrium. The modeling indicated that to match measured autoclave pressures, which often were well below the vapor pressure of water at a given temperature, it was necessary to incorporate water solubility in the oil phase and an activity model for the water in the oil phase which reduced its fugacity below that of pure water. Analysis also indicated that the mild to moderate upgrading of the oil which occurred in experiments that reached 400{degrees}C or more using a FE(III) 2-ethylhexanoate could be reasonably well characterized by a simple first order rate constant of 1.7xl0{sup 8} exp(-20000/T)s{sup {minus}l}. Both gas production and API gravity increase were characterized by this rate constant. Models were able to match the complete pressure history of the autoclave experiments fairly well with relatively simple equilibria models. However, a consistent lower than measured buildup in pressure at peak temperatures was noted in the model calculations. This phenomena was tentatively attributed to an increase in the amount of water entering the vapor phase caused by a change in its activity in the oil phase.

  12. A geometric level set model for ultrasounds analysis

    SciTech Connect

    Sarti, A.; Malladi, R.

    1999-10-01

    We propose a partial differential equation (PDE) for filtering and segmentation of echocardiographic images based on a geometric-driven scheme. The method allows edge-preserving image smoothing and a semi-automatic segmentation of the heart chambers, that regularizes the shapes and improves edge fidelity especially in presence of distinct gaps in the edge map as is common in ultrasound imagery. A numerical scheme for solving the proposed PDE is borrowed from level set methods. Results on human in vivo acquired 2D, 2D+time,3D, 3D+time echocardiographic images are shown.

  13. Analysis of energy balance models using the ERBE data set

    NASA Technical Reports Server (NTRS)

    Graves, Charles E.; North, Gerald R.

    1991-01-01

    A review of Energy Balance Models is presented. Results from the Outgoing Longwave Radiation parameterization are discussed. The albedo parameterizations and the consequences of the new parameterizations are examined.

  14. Magnetic Excursion Recorded in Basalt at Newberry Volcano, Central Oregon

    NASA Astrophysics Data System (ADS)

    Champion, D. E.; Donnelly-Nolan, J. M.; Lanphere, M. A.; Ramsey, D. W.

    2004-12-01

    Paleomagnetic study of basalt flows on the north flank of Newberry Volcano has identified a major eruptive episode that occurred during a magnetic excursion. The measured direction of the basalt flows erupted during the excursion shallows from 81° to 76° inclination along a declination of ˜ 155° . The Virtual Geomagnetic Pole also shallows from 29° to 19° paleolatitude, along a paleolongitude of ˜ 250° , and is located off the west coast of Mexico. Geologic evidence combined with limited argon dating indicate that the basalt erupted from multiple sites about 80,000 years ago, probably during the time of anomalous magnetic directions recorded by ( ˜80 ka) ocean sediments in the Norwegian Sea and the North Atlantic. The westernmost flows erupted from spatter vents located a few km south of the city of Bend, and flowed north through lava tube(s) which form Stevens Cave, Horse Cave, and Redmond Cave among others. This western lobe flowed more than 50 km to the north, over NW-trending faults of the Tumalo Fault Zone that cut the adjacent and underlying basalt of Bend (40Ar/39Ar plateau age of 78±9 ka; isochron age of 77±19 ka); it is overlain by the basaltic andesite of Klawhop Butte (40Ar/39Ar plateau age of 39±6 ka). One sample of the transitional magnetic direction basalt has a K-Ar age of 77±40 ka; another sample has a 40Ar/39Ar plateau age of 92±25 ka and an isochron age of 73±24 ka. The eastern lobe erupted from vents at and near Lava Top Butte, located approximately 15 km SE of the western vents. These eastern lavas flowed through Arnold Cave and formed a broad ~10-12 km rootless shield known as the Badlands, the NE extent of which is about 30 km from Lava Top Butte. The west and east lobes each cover about 150 km2, and comprise an estimated volume of 3-5 km3. Newly acquired 10-meter DEM's and compilation of the mapping in ArcGIS will allow more precise calculation of the total area covered and the volume erupted. Chemical analyses of multiple

  15. Modeling of Protection in Dynamic Simulation Using Generic Relay Models and Settings

    SciTech Connect

    Samaan, Nader A.; Dagle, Jeffery E.; Makarov, Yuri V.; Diao, Ruisheng; Vallem, Mallikarjuna R.; Nguyen, Tony B.; Miller, Laurie E.; Vyakaranam, Bharat; Tuffner, Francis K.; Pai, M. A.; Conto, Jose; Kang, Sun Wook

    2016-07-19

    This paper shows how generic protection relay models available in planning tools can be augmented with settings that are based on NERC standards or best engineering practice. Selected generic relay models in Siemens PSS®E have been used in dynamic simulations in the proposed approach. Undervoltage, overvoltage, underfrequency, and overfrequency relays have been modeled for each generating unit. Distance-relay protection was modeled for transmission system protection. Two types of load-shedding schemes were modeled: underfrequency (frequency-responsive non-firm load shedding) and underfrequency and undervoltage firm load shedding. Several case studies are given to show the impact of protection devices on dynamic simulations. This is useful for simulating cascading outages.

  16. A scoping study of water table excursions induced by seismic and volcanic events

    SciTech Connect

    Carrigan, C.R.; King, G.C.P.; Barr, G.E.

    1990-11-01

    We develop conservative models of water table response to displacements just beneath the water table simulating (1) shallow intrusion of a dike and (2) high level slip on a normal fault locked at the end. For matrix flow, we fine local water table excursions of under 10 m. in cases of isotropic permeability which includes dike inflation of 4 m and fault slips corresponding to earthquakes having a moment magnitude of 7.4. Even for enhancements of vertical permeability up to 10{sup 4}:1, excursions did not exceed 15 m which implies that pumping is strongly volume limited. We also present an analysis of upward directed flow in cracks for the case of earthquake induced pore pressure changes. For matrix properties characteristic of the Calico Hills (vitric) formation and a crack distribution bounding the potential flow capacity of published data, we estimate an upper bound of 0.25 cu m. of ground water per m. of fault length as the amount capable of being pumped to a level 250 m. above the normal water table. While the presence of even larger fractures than assumed might carry more ground water to that level an absolute upper limit of less than 50 cu. m. per m. of fault length is available to be pumped assuming a value n=0.46 for the rock porosity. For less porous rocks typical of the Topopah Spring or Tiva Canyon formations (n{approx}0.10) the upper limit may be reduced to less than 10 cu. m. per m. of fault length. This upper limit depends only upon strain, the height of pumping above the water table and the formation porosity.

  17. Regional Dimensions of the Triple Helix Model: Setting the Context

    ERIC Educational Resources Information Center

    Todeva, Emanuela; Danson, Mike

    2016-01-01

    This paper introduces the rationale for the special issue and its contributions, which bridge the literature on regional development and the Triple Helix model. The concept of the Triple Helix at the sub-national, and specifically regional, level is established and examined, with special regard to regional economic development founded on…

  18. Regional Dimensions of the Triple Helix Model: Setting the Context

    ERIC Educational Resources Information Center

    Todeva, Emanuela; Danson, Mike

    2016-01-01

    This paper introduces the rationale for the special issue and its contributions, which bridge the literature on regional development and the Triple Helix model. The concept of the Triple Helix at the sub-national, and specifically regional, level is established and examined, with special regard to regional economic development founded on…

  19. Leader Succession: A Model and Review for School Settings.

    ERIC Educational Resources Information Center

    Miskel, Cecil; Cosgrove, Dorothy

    Recent research casts doubt on the commonly held notions that administrators affect student learning through instructional leadership and that changing administrators will improve school performance. To help construct a model for examining the process of leader succession that specifies a number of major school process and outcome variables…

  20. Empirical Data Sets for Agent Based Modeling of Crowd Scenarios

    DTIC Science & Technology

    2009-08-06

    Conclusion 2UNCLASSIFIED- Approved for Public Release Crowd Research • Large numbers • Heterogeneous • Individual Actors • Interdependence • Language ... Barriers • Empirical testing is difficult • Simulations require models based on real data, otherwise they are fiction 3UNCLASSIFIED- Approved for

  1. Alternatives to the fixed-set model: A review of appraisal models of emotion.

    PubMed

    Fernando, Julian W; Kashima, Yoshihisa; Laham, Simon M

    2017-01-01

    Over several decades, appraisal theory has emerged as a prominent theoretical framework explaining the elicitation and differentiation of emotions, and has stimulated a great deal of theorising and empirical research. Despite the large amount of research in this area, there are many aspects of appraisal theory and research that remain unclear or problematic. In this review, we identify a common assumption of many appraisal theories-the fixed appraisal set-and argue that this assumption, combined with a lack of explicit theorising about the predicted relationship between appraisals and emotions, leads to a lack of clarity in both appraisal models and the empirical testing of those models. We recommend that appraisal theorists move in a direction already taken by a small number of theorists, and adopt the starting assumption of a variable appraisal set. We further suggest that theories of concepts and categorisation may inform theorising about appraisal-emotion relationships.

  2. Teacher Perceptions of the Role and Value of Excursions in Years 7-10 Geography Education in Victoria, Australia

    ERIC Educational Resources Information Center

    Munday, Penny

    2008-01-01

    Excursions are extremely important to the education of students in the geography curriculum. However, personal observations demonstrated a lack of readiness to conduct excursions in secondary schools. This apprehension of the teachers in this school to implement excursions in geography education was the basis for this study. The study addresses…

  3. High resolution and continuous reconstruction of Blake and Post Blake excursions using cosmogenic radio nuclides in the Antarctic ice core

    NASA Astrophysics Data System (ADS)

    Yokoyama, Y.; Tsunekawa, R.; Takahashi, S.; Miyairi, Y.; Aze, T.; Horiuchi, K.; Matsuzaki, H.; Motoyama, H.

    2015-12-01

    Geomagnetic excursions provide information on field mechanics and serve as a chronostratigraphic tool. Interpretation of sedimentological paleointensity records is complicated, and volcanic rocks provide only non-continuous records. Another means for reconstructing paleomagnetic intensity is analyzing cosmogenic radio nuclides. In this study, we reconstruct the Blake and the Post-Blake Excursions using the cosmogenic radio nuclide 10Be in the Dome Fuji ice core. It has been reported that the Blake Excursion and the Post-Blake Excursion occurred within the Brunhes Chron, at around 115 ka and 100 ka, respectively. These two excursions occurred in quick succession. The Post-Blake Excursion is relatively poorly studied, only being reconstructed from sediments and volcanic rocks. Results indicate there is a significant peaks in 10Be flux that is thought to be reflect respectively the Blake and the Post-Blake Excursions. The maximum 10Be flux during the Post-Blake Excurison is similar to that of the Blake Excursion, suggesting that the geomagnetic dipole field during the Post-Blake Excursion weakened by the same amount as during the Blake Excursion. We also compare the results for the Laschamp Excursion that we also reconstructed from the same ice core to discuss the nature of individual excursions inferred from the cosmogenic radio nuclides data.

  4. Modelling fatigue and the use of fatigue models in work settings.

    PubMed

    Dawson, Drew; Ian Noy, Y; Härmä, Mikko; Akerstedt, Torbjorn; Belenky, Gregory

    2011-03-01

    In recent years, theoretical models of the sleep and circadian system developed in laboratory settings have been adapted to predict fatigue and, by inference, performance. This is typically done using the timing of prior sleep and waking or working hours as the primary input and the time course of the predicted variables as the primary output. The aim of these models is to provide employers, unions and regulators with quantitative information on the likely average level of fatigue, or risk, associated with a given pattern of work and sleep with the goal of better managing the risk of fatigue-related errors and accidents/incidents. The first part of this review summarises the variables known to influence workplace fatigue and draws attention to the considerable variability attributable to individual and task variables not included in current models. The second part reviews the current fatigue models described in the scientific and technical literature and classifies them according to whether they predict fatigue directly by using the timing of prior sleep and wake (one-step models) or indirectly by using work schedules to infer an average sleep-wake pattern that is then used to predict fatigue (two-step models). The third part of the review looks at the current use of fatigue models in field settings by organizations and regulators. Given their limitations it is suggested that the current generation of models may be appropriate for use as one element in a fatigue risk management system. The final section of the review looks at the future of these models and recommends a standardised approach for their use as an element of the 'defenses-in-depth' approach to fatigue risk management. Copyright © 2010 Elsevier Ltd. All rights reserved.

  5. Construction of 3-D Terrain Models from BIG Data Sets

    DTIC Science & Technology

    2014-05-14

    support for dynamically updating the model using the submitted corrections, and using periodic re- computations though an automated system for managing the...NUMBER Pankaj Agarwal Pankaj K. Agarwal, Thomas Moelhave 665502 c. THIS PAGE The public reporting burden for this collection of information is estimated...needed, and completing and reviewing the collection of information . Send comments regarding this burden estimate or any other aspect of this collection

  6. The Applicant Based Training Model Setting Conditions for Recruiting Success

    DTIC Science & Technology

    2002-07-01

    the recruiting districts there are functions performed that help guide and support the billet holders at the RSSs and RSs in the performance of their...one can use to evaluate and prioritize training requirements for key members of RSSs and RS. The following paragraphs offer general conclusions and...training model validates training for recruiters. Due to the geographical dispersion of the RSSs , distance learning initiatives could help support this type

  7. Buried-euxenic-basin model sets Tarim basin potential

    SciTech Connect

    Hsu, K.J. )

    1994-11-28

    The Tarim basin is the largest of the three large sedimentary basins of Northwest China. The North and Southwest depressions of Tarim are underlain by thick sediments and very thin crust. The maximum sediment thickness is more than 15 km. Of the several oil fields of Tarim, the three major fields were discovered during the last decade, on the north flank of the North depression and on the Central Tarim Uplift. The major targets of Tarim, according to the buried-euxenic-basin model, should be upper Paleozoic and lower Mesozoic reservoirs trapping oil and gas condensates from lower Paleozoic source beds. The paper describes the basin and gives a historical perspective of exploration activities and discoveries. It then explains how this basin can be interpreted by the buried-euxenic-basin model. The buried-euxenic-basin model postulates four stages of geologic evolution: (1) Sinian and early Paleozoic platform sedimentation on relic arcs and deep-marine sedimentation in back-arc basins in Xinjiang; (2) Late Paleozoic foreland-basin sedimentation in north Tarim; (3) Mesozoic and Paleogene continental deposition, subsidence under sedimentary load; and (4) Neogene pull-apart basin, wrench faulting and extension.

  8. Dynamic sensitivity analysis of long running landslide models through basis set expansion and meta-modelling

    NASA Astrophysics Data System (ADS)

    Rohmer, Jeremy

    2016-04-01

    Predicting the temporal evolution of landslides is typically supported by numerical modelling. Dynamic sensitivity analysis aims at assessing the influence of the landslide properties on the time-dependent predictions (e.g., time series of landslide displacements). Yet two major difficulties arise: 1. Global sensitivity analysis require running the landslide model a high number of times (> 1000), which may become impracticable when the landslide model has a high computation time cost (> several hours); 2. Landslide model outputs are not scalar, but function of time, i.e. they are n-dimensional vectors with n usually ranging from 100 to 1000. In this article, I explore the use of a basis set expansion, such as principal component analysis, to reduce the output dimensionality to a few components, each of them being interpreted as a dominant mode of variation in the overall structure of the temporal evolution. The computationally intensive calculation of the Sobol' indices for each of these components are then achieved through meta-modelling, i.e. by replacing the landslide model by a "costless-to-evaluate" approximation (e.g., a projection pursuit regression model). The methodology combining "basis set expansion - meta-model - Sobol' indices" is then applied to the La Frasse landslide to investigate the dynamic sensitivity analysis of the surface horizontal displacements to the slip surface properties during the pore pressure changes. I show how to extract information on the sensitivity of each main modes of temporal behaviour using a limited number (a few tens) of long running simulations. In particular, I identify the parameters, which trigger the occurrence of a turning point marking a shift between a regime of low values of landslide displacements and one of high values.

  9. Magnetic Field Modeling with a Set of Individual Localized Coils

    PubMed Central

    Juchem, Christoph; Nixon, Terence W.; McIntyre, Scott; Rothman, Douglas L.; de Graaf, Robin A.

    2010-01-01

    A set of generic, circular individual coils is shown to be capable of generating highly complex magnetic field distributions in a flexible fashion. Arbitrarily oriented linear field gradients can be generated in three-dimensional as well as sliced volumes at amplitudes that allow imaging applications. The multi-coil approach permits the simultaneous generation of linear MRI encoding fields and complex shim fields by the same setup, thereby reducing system complexity. The choice of the sensitive volume over which the magnetic fields are optimized remains temporally and spatially variable at all times. The restriction of the field synthesis to experimentally relevant, smaller volumes such as single slices directly translates into improved efficiency, i.e. higher magnetic field amplitudes and/or reduced coil currents. For applications like arterial spin labeling, signal spoiling and diffusion weighting, perfect linearity of the gradient fields is not required and reduced demands on accuracy can also be readily translated into improved efficiency. The first experimental realization was achieved for mouse head MRI with 24 coils that were mounted on the surface of a cylindrical former. Oblique linear field gradients of 20 kHz/cm (47 mT/m) were generated with a maximum current of 1.4 A which allowed radial imaging of a mouse head. The potential of the new approach for generating arbitrary magnetic field shapes is demonstrated by synthesizing the more complex, higher order spherical harmonic magnetic field distributions X2-Y2, Z2 and Z2X. The new multi-coil approach provides the framework for the integration of conventional imaging and shim coils into a single multi-coil system in which shape, strength, accuracy and spatial coverage of the magnetic field can be specifically optimized for the application at hand. PMID:20347360

  10. Modeling Non-linear Ocean Wave Amplification in Coastal Settings

    NASA Astrophysics Data System (ADS)

    Harrington, J. P.; Cox, R.; Brennan, J.; Clancy, C.; Herterich, J.; Dias, F.

    2016-12-01

    Coastal boulder deposits occur in many locations worldwide, along high-energy coastlines. They contain clasts with masses >100 t in some cases, deposited many m above high water and many tens of m inland, often at the top of steep cliffs. The clasts are moved by storm waves, despite being at elevations and inshore distances that should be unreachable by recorded sea states. The question is, therefore, how are storm waves amplified to the extent needed to transport megagravel inshore? As climate changes, with the risk of increased storminess, it is important to understand this issue, as it is central to understanding inland transmission of fluid forces during storm events. Numerical modeling is a powerful technique for exploring this complex problem. We used a conformal mapping solution to Euler's equations to explore runup of 2D wave trains against a vertical barrier (simulating a coastal cliff). Previous research showed that modeled wave trains passing over flat bathymetry experience vertical runup up to 6 times the initial wave amplitude for both short- (3 times water depth) and long- (125 times depth) wavelength waves. We increased the model complexity by including a bathymetric step, causing an abrupt depth decrease before the cliff. We found that the uneven bathymetry further amplified both short- and long-wavelength waves. Short-wavelength simulations were hampered by our code's limitations in solving Euler's equations for steep waves, and crashed before reaching maximum runups: ongoing work focuses on solving the computational problems. These problems did not affect the long-wavelength simulations, however, which returned maximum runup values up to 10 times initial amplitude. The key message is that bathymetric effects can drive large wave-height amplifications. This suggests that enhanced runup for long-wavelength waves caused by variable bathymetry could be a key factor in cases where ocean waves overtop steep cliffs and transport boulders well above high

  11. Causal Inference and Model Selection in Complex Settings

    NASA Astrophysics Data System (ADS)

    Zhao, Shandong

    Propensity score methods have become a part of the standard toolkit for applied researchers who wish to ascertain causal effects from observational data. While they were originally developed for binary treatments, several researchers have proposed generalizations of the propensity score methodology for non-binary treatment regimes. In this article, we firstly review three main methods that generalize propensity scores in this direction, namely, inverse propensity weighting (IPW), the propensity function (P-FUNCTION), and the generalized propensity score (GPS), along with recent extensions of the GPS that aim to improve its robustness. We compare the assumptions, theoretical properties, and empirical performance of these methods. We propose three new methods that provide robust causal estimation based on the P-FUNCTION and GPS. While our proposed P-FUNCTION-based estimator preforms well, we generally advise caution in that all available methods can be biased by model misspecification and extrapolation. In a related line of research, we consider adjustment for posttreatment covariates in causal inference. Even in a randomized experiment, observations might have different compliance performance under treatment and control assignment. This posttreatment covariate cannot be adjusted using standard statistical methods. We review the principal stratification framework which allows for modeling this effect as part of its Bayesian hierarchical models. We generalize the current model to add the possibility of adjusting for pretreatment covariates. We also propose a new estimator of the average treatment effect over the entire population. In a third line of research, we discuss the spectral line detection problem in high energy astrophysics. We carefully review how this problem can be statistically formulated as a precise hypothesis test with point null hypothesis, why a usual likelihood ratio test does not apply for problem of this nature, and a doable fix to correctly

  12. Two Possible but Unconfirmed Paleomagnetic Excursions in Pleistocene Lacustrine Sediments in North America and Mexico

    NASA Astrophysics Data System (ADS)

    Liddicoat, J. C.

    2011-12-01

    The paleomagnetic literature is replete with reports of investigations of continuous field behavior (secular variation) using volcanic rocks and lacustrine and marine sediments from around the globe, and some of the reports are about paleomagnetic excursions. The Laschamp Excursion in volcanic rocks in the Massif Central of France (Bonhommet and Babkine, 1967) and Mono Lake Excursion in exposed lacustrine sediment in California (Denham and Cox, 1971) are two excursions that are recognized. At other localities and for different time intervals, confirmation of some excursions in sediment has not been successful at nearby sites where the deposits are believed to be the same age. An example is in the Basin of Mexico at Tlapacoya (19.4 N, 261.2 E)(Liddicoat et al., 1979). Another excursion that has not been confirmed but might have occurred is recorded in Pleistocene Lake Bonneville sediments that are exposed in the bank of the Sevier River near Delta, Utah (39.4 N, 247.6 E). In Mexico and Utah, the excursion is in a single, fully-oriented hand sample that was prepared into consecutive, 2-cm-thick horizons. Each horizon contains six samples that were demagnetized in an alternating field, and for each Lake Bonneville horizon the scatter of directions is 4 degrees or less. Several possibilities for why the excursion at Tlapacoya could not be confirmed were presented (Liddicoat et al., 1979), leaving open the possibility that the excursion might have occurred in Mexico about 14,500 years ago. The field behavior in Utah where the sediments are older than those at Tlapacoya by several tens of thousands of years (Oviatt et al., 1994) is nearly identical to the behavior recorded at Tlapacoya. At both localities, a path of the Virtual Geomagnetic Poles during the excursion is confined to a narrow meridional zone centered at about 200 E longitude and that descends to about 15 N latitude. The difficulty of confirming the anomalous field behavior at Tlapacoya and in Utah

  13. Two Possible but Unconfirmed Palaeomagnetic Excursions in Pleistocene Lacustrine Sediments in North America and Mexico

    NASA Astrophysics Data System (ADS)

    Liddicoat, J.; Coe, R.; Oviatt, J.

    2012-04-01

    The palaeomagnetic literature is replete with reports of investigations of continuous field behaviour (secular variation) using volcanic rocks and lacustrine and marine sediments, and some of the reports are about palaeomagnetic excursions. The Laschamp Excursion in volcanic rocks in the Massif Central of France (Bonhommet and Babkine, 1967) and Mono Lake Excursion in exposed lacustrine sediment in California (Denham and Cox, 1971) are two excursions that generally are accepted as having occurred in the late Pleistocene. At other localities and for different time intervals, confirmation of some excursions in sediment has not been successful at nearby sites where the deposits are believed to be the same age. An example is in the Basin of Mexico at Tlapacoya (19.4˚ N, 261.2˚ E) in lacustrine sediments about 14,500 years old (Liddicoat et al., 1979). Another excursion that has not been confirmed but might have occurred is recorded in Lake Bonneville sediments that are exposed in the bank of the Sevier River near Delta, Utah (39.4˚ N, 247.6˚ E). In Mexico and Utah, the excursions are in a single, fully-oriented hand sample that was prepared into consecutive, 2-cm-thick horizons, each consisting of six subsamples. The subsamples were demagnetized in an alternating field to at least 60 mT or when possible because of consolidation, thermally demagnetized to 600˚ C; for each Lake Bonneville horizon, the scatter of palaeomagnetic directions is 4˚ or less. Several possibilities for why the excursion at Tlapacoya could not be confirmed were presented (Liddicoat et al., 1979), leaving open the possibility that the excursion might have occurred in Mexico. The field behaviour in Utah where the sediments are older than those at Tlapacoya by several tens of thousands of years (Oviatt et al., 1994) is nearly identical to the behaviour recorded at Tlapacoya. At both localities, a path of the Virtual Geomagnetic Poles during the excursion is confined to a narrow meridional zone

  14. Laryngeal transplantation in the setting of cancer: a rat model.

    PubMed

    Shipchandler, Taha Z; Lorenz, Robert R; Lee, Walter T; Teker, Aysenur Meric; Dan, Olivia; Strome, Marshall

    2008-12-01

    Traditional immunosuppressive regimens make laryngeal transplantation in cancer patients prohibitive because of the increased risk of recurrence. Everolimus, a recently developed immunosuppressant, has demonstrated significant antitumor properties. The purpose of this study was to examine the effects of everolimus alone and in combination with other immunosuppressants on tumor growth in a combined laryngeal transplantation and tumor model. Animal, prospective, randomized, controlled, and blinded. One million squamous cell carcinoma cells (SCC-158) were injected intravenously into a total of 40 rats 1 day before laryngeal transplantation. Rats were divided into four groups differing by immunosuppressive regimens. Lung surface metastases were counted 21 days after inoculation, and numerical transplantation rejection scores were recorded. A separate experiment for comparison was performed with no transplant on 24 rats, but with the same immunosuppressive treatment groups. The median number of lung surface metastases were: a) control (i.e., no immunosuppression): 85; b) everolimus 1.0 mg/kg: 25; c) tacrolimus 1.2 mg/kg: 1650; d) everolimus 1.0 mg/kg + tacrolimus 0.05 mg/kg: 1300. Rats receiving everolimus alone showed a statistically significant decrease in pulmonary surface metastases compared with the other groups. Transplanted rats had no difference in their outcomes when compared with non-transplanted rats. Everolimus significantly decreases SCC-158 growth in our combined transplantation and tumor model compared with controls and other immunosuppressants.

  15. Dating the Laschamp Excursion: Why Speleothems are Valuable Tools for Constraining the Timing and Duration of Short-Lived Geomagnetic Events

    NASA Astrophysics Data System (ADS)

    Lascu, I.; Feinberg, J. M.; Dorale, J. A.; Cheng, H.; Edwards, R. L.

    2015-12-01

    Short-lived geomagnetic events are reflections of geodynamo behavior at small length scales. A rigorous documentation of the anatomy, timing, duration, and frequency of centennial-to-millennial scale geomagnetic events can be invaluable for theoretical and numerical geodynamo models, and for the understanding the finer dynamics of the Earth's core. A critical ingredient for characterizing such geomagnetic instabilities are tightly constrained age models that enable high-resolution magnetostratigraphies. Here we focus on a North American speleothem geomagnetic record of the Laschamp excursion, which was the first geomagnetic excursion recognized and described in the paleomagnetic record, and remains the most studied event of its kind. The geological significance of the Laschamp lies chiefly in the fact that it constitutes a global time-synchronous geochronological marker. The Laschamp excursion occurred around the time of the demise of Homo neanderthalensis, in conjunction with high-amplitude, rapid climatic oscillations leading into the Last Glacial Maximum, and precedes a major supervolcano eruption in the Mediterranean. Thus, the precise determination of the timing and duration of the Laschamp would help in elucidating major scientific questions situated at the intersection of geology, paleoclimatology, and anthropology. Here we present a geomagnetic record from a stalagmite collected in Crevice Cave, Missouri, which we have dated using a combination of high-precision 230Th ages and annual layer counting using confocal microscopy. We have found a maximum duration for the Laschamp that spans the interval 42,250-39,700 years BP, and an age of 41,100 ± 350 years BP for the height of the excursion. During this period relative paleointensity decreased by an order of magnitude and the virtual geomagnetic pole was located at southerly latitudes. Our chronology provides the first robust bracketing for the Laschamp excursion, and improves on previous age determinations

  16. Development of an Optimum Tracer Set for Apportioning Emissions of Individual Power Plants Using Highly Time-Resolved Measurements and Advanced Receptor Modeling

    SciTech Connect

    John Ondov; Gregory Beachley

    2007-07-05

    In previous studies, 11 elements (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se, and Zn) were determined in 30-minute aerosol samples collected with the University of Maryland Semicontinuous Elements in Aerosol Sampler (SEAS; Kidwell and Ondov, 2001, 2004; SEAS-II) in several locations in which air quality is influenced by emissions from coal- or oil-fired power plants. At this time resolution, plumes from stationary high temperature combustion sources are readily detected as large excursions in ambient concentrations of elements emitted by these sources (Pancras et al. ). Moreover, the time-series data contain intrinsic information on the lateral diffusion of the plume (e.g., {sigma}{sub y}), which Park et al. (2005 and 2006) have exploited in their Pseudo-Deterministic Receptor Model (PDRM), to calculate emission rates of SO{sub 2} and 11 elements (mentioned above) from four individual coal- and oil-fired power plants in the Tampa Bay area. In the current project, we proposed that the resolving power of source apportionment methods might be improved by expanding the set of maker species and that there exist some optimum set of marker species that could be used. The ultimate goal was to determine the utility of using additional elements to better identify and isolate contributions of individual power plants to ambient levels of PM and its constituents. And, having achieved better resolution, achieve, also, better emission rate estimates. In this study, we optimized sample preparation and instrumental protocols for simultaneous analysis of 28 elements in dilute slurry samples collected with the SEAS with a new state-of-the-art Thermo-Systems, Inc., X-series II, Inductively Coupled Plasma Mass Spectroscopy (ICP-MS), and reanalyzed the samples previously collected in Tampa during the modeling period studied by Park et al. (2005) in which emission rates from four coal- and oil-fired power plants affected air quality at the sampling site. In the original model, Park et al

  17. Level set methods for modelling field evaporation in atom probe.

    PubMed

    Haley, Daniel; Moody, Michael P; Smith, George D W

    2013-12-01

    Atom probe is a nanoscale technique for creating three-dimensional spatially and chemically resolved point datasets, primarily of metallic or semiconductor materials. While atom probe can achieve local high-level resolution, the spatial coherence of the technique is highly dependent upon the evaporative physics in the material and can often result in large geometric distortions in experimental results. The distortions originate from uncertainties in the projection function between the field evaporating specimen and the ion detector. Here we explore the possibility of continuum numerical approximations to the evaporative behavior during an atom probe experiment, and the subsequent propagation of ions to the detector, with particular emphasis placed on the solution of axisymmetric systems, such as isolated particles and multilayer systems. Ultimately, this method may prove critical in rapid modeling of tip shape evolution in atom probe tomography, which itself is a key factor in the rapid generation of spatially accurate reconstructions in atom probe datasets.

  18. Evolution of Autocatalytic Sets in Computational Models of Chemical Reaction Networks

    NASA Astrophysics Data System (ADS)

    Hordijk, Wim

    2016-06-01

    Several computational models of chemical reaction networks have been presented in the literature in the past, showing the appearance and (potential) evolution of autocatalytic sets. However, the notion of autocatalytic sets has been defined differently in different modeling contexts, each one having some shortcoming or limitation. Here, we review four such models and definitions, and then formally describe and analyze them in the context of a mathematical framework for studying autocatalytic sets known as RAF theory. The main results are that: (1) RAF theory can capture the various previous definitions of autocatalytic sets and is therefore more complete and general, (2) the formal framework can be used to efficiently detect and analyze autocatalytic sets in all of these different computational models, (3) autocatalytic (RAF) sets are indeed likely to appear and evolve in such models, and (4) this could have important implications for a possible metabolism-first scenario for the origin of life.

  19. Evolution of Autocatalytic Sets in Computational Models of Chemical Reaction Networks.

    PubMed

    Hordijk, Wim

    2016-06-01

    Several computational models of chemical reaction networks have been presented in the literature in the past, showing the appearance and (potential) evolution of autocatalytic sets. However, the notion of autocatalytic sets has been defined differently in different modeling contexts, each one having some shortcoming or limitation. Here, we review four such models and definitions, and then formally describe and analyze them in the context of a mathematical framework for studying autocatalytic sets known as RAF theory. The main results are that: (1) RAF theory can capture the various previous definitions of autocatalytic sets and is therefore more complete and general, (2) the formal framework can be used to efficiently detect and analyze autocatalytic sets in all of these different computational models, (3) autocatalytic (RAF) sets are indeed likely to appear and evolve in such models, and (4) this could have important implications for a possible metabolism-first scenario for the origin of life.

  20. Process Setting through General Linear Model and Response Surface Method

    NASA Astrophysics Data System (ADS)

    Senjuntichai, Angsumalin

    2010-10-01

    The objective of this study is to improve the efficiency of the flow-wrap packaging process in soap industry through the reduction of defectives. At the 95% confidence level, with the regression analysis, the sealing temperature, temperatures of upper and lower crimper are found to be the significant factors for the flow-wrap process with respect to the number/percentage of defectives. Twenty seven experiments have been designed and performed according to three levels of each controllable factor. With the general linear model (GLM), the suggested values for the sealing temperature, temperatures of upper and lower crimpers are 185, 85 and 85° C, respectively while the response surface method (RSM) provides the optimal process conditions at 186, 89 and 88° C. Due to different assumptions between percentage of defective and all three temperature parameters, the suggested conditions from the two methods are then slightly different. Fortunately, the estimated percentage of defectives at 5.51% under GLM process condition and the predicted percentage of defectives at 4.62% under RSM process condition are not significant different. But at 95% confidence level, the percentage of defectives under RSM condition can be much lower approximately 2.16% than those under GLM condition in accordance with wider variation. Lastly, the percentages of defectives under the conditions suggested by GLM and RSM are reduced by 55.81% and 62.95%, respectively.

  1. Genetic Optimization of Training Sets for Improved Machine Learning Models of Molecular Properties.

    PubMed

    Browning, Nicholas J; Ramakrishnan, Raghunathan; von Lilienfeld, O Anatole; Roethlisberger, Ursula

    2017-04-06

    The training of molecular models of quantum mechanical properties based on statistical machine learning requires large data sets which exemplify the map from chemical structure to molecular property. Intelligent a priori selection of training examples is often difficult or impossible to achieve, as prior knowledge may be unavailable. Ordinarily representative selection of training molecules from such data sets is achieved through random sampling. We use genetic algorithms for the optimization of training set composition consisting of tens of thousands of small organic molecules. The resulting machine learning models are considerably more accurate: in the limit of small training sets, mean absolute errors for out-of-sample predictions are reduced by up to ∼75%. We discuss and present optimized training sets consisting of 10 molecular classes for all molecular properties studied. We show that these classes can be used to design improved training sets for the generation of machine learning models of the same properties in similar but unrelated molecular sets.

  2. Be a Healthy Role Model for Children: 10 Tips for Setting Good Examples

    MedlinePlus

    10 tips Nutrition Education Series be a healthy role model for children 10 tips for setting good examples You are the ... such as candy or cookies—as replacement foods. 10 be a good food role model Try new ...

  3. Fractionation between inorganic and organic carbon during the Lomagundi (2.22 2.1 Ga) carbon isotope excursion

    NASA Astrophysics Data System (ADS)

    Bekker, A.; Holmden, C.; Beukes, N. J.; Kenig, F.; Eglinton, B.; Patterson, W. P.

    2008-07-01

    The Lomagundi (2.22-2.1 Ga) positive carbon isotope excursion in shallow-marine sedimentary carbonates has been associated with the rise in atmospheric oxygen, but subsequent studies have demonstrated that the carbon isotope excursion was preceded by the rise in atmospheric oxygen. The amount of oxygen released to the exosphere during the Lomagundi excursion is constrained by the average global fractionation between inorganic and organic carbon, which is poorly characterized. Because dissolved inorganic and organic carbon reservoirs were arguably larger in the Paleoproterozoic ocean, at a time of lower solar luminosity and lower ocean redox state, decoupling between these two variables might be expected. We determined carbon isotope values of carbonate and organic matter in carbonates and shales of the Silverton Formation, South Africa and in the correlative Sengoma Argillite Formation, near the border in Botswana. These units were deposited between 2.22 and 2.06 Ga along the margin of the Kaapvaal Craton in an open-marine deltaic setting and experienced lower greenschist facies metamorphism. The prodelta to offshore marine shales are overlain by a subtidal carbonate sequence. Carbonates exhibit elevated 13C values ranging from 8.3 to 11.2‰ vs. VPDB consistent with deposition during the Lomagundi positive excursion. The total organic carbon (TOC) contents range from 0.01 to 0.6% and δ13C values range from - 24.8 to - 13.9‰. Thus, the isotopic fractionation between organic and carbonate carbon was on average 30.3 ± 2.8‰ ( n = 32) in the shallow-marine environment. The underlying Sengoma shales have highly variable TOC contents (0.14 to 21.94%) and δ13C values (- 33.7 to - 20.8‰) with an average of - 27.0 ± 3.0‰ ( n = 50). Considering that the shales were also deposited during the Lomagundi excursion, and taking δ13C values of the overlying carbonates as representative of the δ13C value of dissolved inorganic carbon during shale deposition, a carbon

  4. Levator excursion as a predictor of both eyelid lag and lagophthalmos in thyroid eye disease.

    PubMed

    Lelli, Gary J; Duong, Jimmy K; Kazim, Michael

    2010-01-01

    To evaluate the relationship between levator excursion and both eyelid lag and lagophthalmos in thyroid eye disease. We retrospectively reviewed 104 eyelids of 52 thyroid eye disease patients over a 9-month interval by measuring levator function (mm), eyelid lag (0-4+) and lagophthalmos (mm). Lower levator excursion is associated with higher eyelid lag scores (p < 0.001) and with greater degrees of lagophthalmos (p < 0.001). Both associations were upheld after adjustment for upper eyelid margin reflex distance and Hertel exophthalmometry (p < 0.0001). For every 1-mm decrease in levator function, eyelid lag score increases on average by 0.29 and lagophthalmos increases on average by 0.23 mm. Diminished levator excursion is associated with increasing levels of eyelid lag and lagophthalmos. Levator excursion is an important clinical measurement in thyroid eye disease patients and may replace eyelid lag grading and lagophthalmos as a more accurate indicator of eyelid retraction in thyroid eye disease.

  5. A Science and Technology Excursion-based Unit of Work: The Human Body.

    ERIC Educational Resources Information Center

    Terry, Laura

    2000-01-01

    Presents a unit of work based on a few systems of the human body. Stretches students' learning beyond the classroom into the local community by going on an excursion to Kalgoorlie Regional Hospital. (ASK)

  6. A Science and Technology Excursion-based Unit of Work: The Human Body.

    ERIC Educational Resources Information Center

    Terry, Laura

    2000-01-01

    Presents a unit of work based on a few systems of the human body. Stretches students' learning beyond the classroom into the local community by going on an excursion to Kalgoorlie Regional Hospital. (ASK)

  7. A global deglacial negative carbon isotope excursion in speleothem calcite

    NASA Astrophysics Data System (ADS)

    Breecker, D.

    2015-12-01

    δ13C values of speleothem calcite decreased globally during the last deglaciation defining a carbon isotope excursion (CIE) despite relatively constant δ13C values of carbon in the ocean-atmosphere system. The magnitude of the CIE varied with latitude, increasing poleward from ~2‰ in the tropics to as much as 7‰ at high latitudes. This recent CIE provides an interesting comparison with CIEs observed in deep time. A substantial portion of this CIE can be explained by the increase in atmospheric pCO2 that accompanied deglaciation. The dependence of C3 plant δ13C values on atmospheric pCO2 predicts a 2‰ δ13C decrease driven by the deglacial pCO2 increase. I propose that this signal was transferred to caves and thus explains nearly 100% of the CIE magnitude observed in the tropics and no less than 30% at the highest latitudes in the compilation. An atmospheric pCO2 control on speleothem δ13C values, if real, will need to be corrected for using ice core data before δ13C records can be interpreted in a paleoclimate context. The decrease in the magnitude of the equilibrium calcite-CO2 carbon isotope fractionation factor explains a maximum of 1‰ of the CIE at the highest northern latitude in the compilation, which experienced the largest deglacial warming. Much of the residual extratropical CIE was likely driven by increasing belowground respiration rates, which were presumably pronounced at high latitudes as glacial retreat exposed fresh surfaces and/or vegetation density increased. The largest increases in belowground respiration would have therefore occurred at the highest latitudes, explaining the meridional trend. This work supports the notion that increases in atmospheric pCO2 and belowground respiration rates can result in large CIEs recorded in terrestrial carbonates, which, as previously suggested, may explain the magnitude of the PETM CIE as recorded by paleosol carbonates.

  8. The Effects of Credibility, Reliance, and Exposure on Media Agenda-Setting: A Path Analysis Model.

    ERIC Educational Resources Information Center

    Wanta, Wayne; Hu, Yu-Wei

    1994-01-01

    Uses path analysis to investigate a model of agenda-setting. Supports the model, showing that, if individuals perceive the media to be highly credible, they will rely on the media for information, will increase their exposure to media messages and in turn will become more susceptible to agenda-setting. (SR)

  9. Sedimentary and Volcanic Records of the Laschamp and Mono Lake Excursions from Australia and New Zealand

    NASA Astrophysics Data System (ADS)

    Ingham, E. M.; Roberts, A. P.; Turner, G. M.; Heslop, D.; Ronge, T.; Conway, C.; Leonard, G.; Townsend, D.; Tiedemann, R.; Lamy, F.; Calvert, A. T.

    2014-12-01

    Geomagnetic excursions are short-lived deviations of the geomagnetic field from the normal range of secular variation. Despite significant advances in geomagnetic excursion research over the past 20 years, fundamental questions remain concerning the typical duration and global morphology of excursional geomagnetic fields. To answer such questions, more high-resolution, chronologically well-constrained excursion records are required, particularly from the Southern Hemisphere. We present preliminary paleomagnetic records of the Laschamp (~41 ka) and Mono Lake (~35 ka) excursions from three marine sediment cores from the Bounty Trough, New Zealand margin, and complementary volcanic records of the Laschamp excursion from lavas of Mt Ruapehu, New Zealand. Relatively high sedimentation rates of 12 - 26 cm/kyr in the Bounty Trough during glacial periods allow identification of excursional field behavior at each of the studied core locations. Each core displays one or two excursional events, with rapid directional swings between stable normal polarity and reversed excursional directions, each associated with coincident relative paleointensity minima. These anomalous paleomagnetic directions are interpreted to represent the Laschamp and Mono Lake excursions, based on a combination of tephrochronology, radiocarbon dating, and cyclostratigraphy (defined from core-scanning X-ray fluorescence and magnetic susceptibility records). Beside these records, we present results from fourteen lava flows, on Mt Ruapehu, for which 40Ar-39Ar dating indicates ages of between 39 and 45 ka. The step heating 40Ar-39Ar experiments produced particularly flat age plateaus, with corresponding 2 s.d. errors mostly approaching 1 kyr. The youngest and oldest flows carry normal polarity magnetization, however six flows, dated between 41 and 43 ka, display transitional field characteristics. Three of these flows display a declination swing of around 180o, which coincides with a previously published

  10. Parameter Set Uniqueness and Confidence Limits in Model Identification of Insulin Transport Models for Simulation Data Diabetic Patient Models

    PubMed Central

    Farmer, Terry G.; Edgar, Thomas F.; Peppas, Nicholas A.

    2011-01-01

    Background The use of patient models describing the dynamics of glucose, insulin, and possibly other metabolic species associated with glucose regulation allows diabetes researchers to gain insights regarding novel therapies via simulation. However, such models are only useful when model parameters are effectively estimated with patient data. Methods The use of least squares to effectively estimate model parameters from simulation data was investigated by observing factors that influence the accuracy of estimates for the model parameters from a data set generated using a model with known parameters. An intravenous insulin pharmacokinetic model was used to generate the insulin response of a patient with type 1 diabetes mellitus to a series of step changes in the insulin infusion rate from an external insulin pump. The effects of using user-defined gradient and Hessian calculations on both parameter estimations and the 95% confidence limits of the estimated parameter sets were investigated. Results Estimations performed by either solver without user-supplied quantities were highly dependent on the initial guess of the parameter set, with relative confidence limits greater than ±100%. The use of user-defined quantities allowed the one-compartment model parameters to be effectively estimated. While the two-compartment model parameter estimation still depended on the initial parameter set specification, confidence limits were decreased, and all fits to simulation data were very good. Conclusions The use of user-defined gradients and Hessian matrices results in more accurate parameter estimations for insulin transport models. Improved estimation could result in more accurate simulations for use in glucose control system design. PMID:18260776

  11. Head excursion of restrained human volunteers and hybrid III dummies in steady state rollover tests.

    PubMed

    Moffatt, Edward; Hare, Barry; Hughes, Raymond; Lewis, Lance; Iiyama, Hiroshi; Curzon, Anne; Cooper, Eddie

    2003-01-01

    Seatbelts provide substantial benefits in rollover crashes, yet occupants still receive head and neck injuries from contacting the vehicle roof interior when the roof exterior strikes the ground. Prior research has evaluated rollover restraint performance utilizing anthropomorphic test devices (dummies), but little dynamic testing has been done with human volunteers to learn how they move during rollovers. In this study, the vertical excursion of the head of restrained dummies and human subjects was measured in a vehicle being rotated about its longitudinal roll axis at roll rates from 180-to-360 deg/sec and under static inversion conditions. The vehicle's restraint design was the commonly used 3-point seatbelt with continuous loop webbing and a sliding latch plate. This paper presents an analysis of the observed occupant motion and provides a comparison of dummy and human motion under similar test conditions. Thirty-five tests (eighteen static and seventeen dynamic) were completed using two different sizes of dummies and human subjects in both near and far-side roll directions. The research indicates that far-side rollovers cause the restrained test subjects to have greater head excursion than near-side rollovers, and that static inversion testing underestimates head excursion for far-side occupants. Human vertical head excursion of up to 200 mm was found at a roll rate of 220 deg/sec. Humans exhibit greater variability in head excursion in comparison to dummies. Transfer of seatbelt webbing through the latch plate did not correlate directly with differences in head excursion.

  12. Late Ordovician (Turinian-Chatfieldian) carbon isotope excursions and their stratigraphic and paleoceanographic significance

    USGS Publications Warehouse

    Ludvigson, Greg A.; Witzke, B.J.; Gonzalez, Luis A.; Carpenter, S.J.; Schneider, C.L.; Hasiuk, F.

    2004-01-01

    Five positive carbon isotope excursions are reported from Platteville-Decorah strata in the Upper Mississippi Valley. All occur in subtidal carbonate strata, and are recognized in the Mifflin, Grand Detour, Quimbys Mill, Spechts Ferry, and Guttenberg intervals. The positive carbon isotope excursions are developed in a Platteville-Decorah succession in which background ??13C values increase upward from about -2??? at the base to about 0??? Vienna Pee Dee belemnite (VPDB) at the top. A regional north-south ??13C gradient, with lighter values to the north and heavier values to the south is also noted. Peak excursion ??13C values of up to +2.75 are reported from the Quimbys Mill excursion, and up to +2.6 from the Guttenberg excursion, although there are considerable local changes in the magnitudes of these events. The Quimbys Mill, Spechts Ferry, and Guttenberg carbon isotope excursions occur in units that are bounded by submarine disconformities, and completely starve out in deeper, more offshore areas. Closely spaced chemostratigraphic profiles of these sculpted, pyrite-impregnated hardground surfaces show that they are associated with very abrupt centimeter-scale negative ??13C shifts of up to several per mil, possibly resulting from the local diagenetic effects of incursions of euxinic bottom waters during marine flooding events. ?? 2004 Elsevier B.V. All rights reserved.

  13. A novel level set model with automated initialization and controlling parameters for medical image segmentation.

    PubMed

    Liu, Qingyi; Jiang, Mingyan; Bai, Peirui; Yang, Guang

    2016-03-01

    In this paper, a level set model without the need of generating initial contour and setting controlling parameters manually is proposed for medical image segmentation. The contribution of this paper is mainly manifested in three points. First, we propose a novel adaptive mean shift clustering method based on global image information to guide the evolution of level set. By simple threshold processing, the results of mean shift clustering can automatically and speedily generate an initial contour of level set evolution. Second, we devise several new functions to estimate the controlling parameters of the level set evolution based on the clustering results and image characteristics. Third, the reaction diffusion method is adopted to supersede the distance regularization term of RSF-level set model, which can improve the accuracy and speed of segmentation effectively with less manual intervention. Experimental results demonstrate the performance and efficiency of the proposed model for medical image segmentation.

  14. Development of technique to detect and classify small-scale magnetic flux cancellation and rapid blue-shifted excursions

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Deng, Na; Lamb, Derek A.; Jing, Ju; Liu, Chang; Liu, Rui; Park, Sung-Hong; Wang, Haimin

    2015-07-01

    We present a set of tools for detecting small-scale solar magnetic cancellations and the disk counterpart of type II spicules (the so-called Rapid Blueshifted Excursions (RBEs)), using line-of-sight photospheric magnetograms and chromospheric spectroscopic observations, respectively. For tracking magnetic cancellation, we improve the Southwest Automatic Magnetic Identification Suite (SWAMIS) so that it is able to detect certain obscure cancellations that can be easily missed. For detecting RBEs, we use a normalized reference profile to reduce false-positive detections caused by the non-uniform background and seeing condition. Similar to the magnetic feature tracking in SWAMIS, we apply a dual-threshold method to enhance the accuracy of RBE detection. These tools are employed to analyze our coordinated observations using the Interferometric BIdimensional Spectrometer at the Dunn Solar Telescope of the National Solar Observatory and Hinode. We present the statistical properties of magnetic cancellations and RBEs, and explore their correlation using this data set.

  15. Condyle Excursion Angle, Articular Eminence Inclination, and Temporomandibular Joint Morphologic Relations With Disc Displacement.

    PubMed

    Rabelo, Katharina Alves; Sousa Melo, Saulo Leonardo; Torres, Marianna Guanaes Gomes; Campos, Paulo Sérgio F; Bento, Patrícia Meira; Melo, Daniela Pita de

    2017-05-01

    The aim of this study was to evaluate the relations of the condyle excursion angle (CEA) and the morphology and morphometry of the articular eminence to disc displacement (DD) using magnetic resonance imaging (MRI) of symptomatic patients. MRIs of 199 temporomandibular joints (TMJs) were evaluated. Qualitative and quantitative morphologic analyses were performed with tools available in PACS 11.0 (Carestream Health, Inc, Rochester, NY). The articular eminence inclination (AEI), eminence height (EH), CEA, and articular eminence morphologic shape were evaluated. Statistical analyses were used to evaluate any possible association of the variables with DD in the closed- and open-mouth positions, age, and gender. The significance level was set at .05. Elderly women (>60 yr) presented higher prevalence values (43.26%). There was no statistical correlation between DD and gender (P = .4290). Higher mean values of the AEI and EH were associated with box-shaped eminences. The EH, AEI, and CEA were not related to the presence or absence of DD and the different types of DD. The AEI (P = .002) and CEA (P < .001) values were higher for TMJs with disc reduction in the open-mouth position. Disc position in the closed- and open-mouth positions is not influenced by articular eminence morphology; however, the AEI and CEA have an influence on disc reduction. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  16. Extrapolatable analytical functions for tendon excursions and moment arms from sparse datasets

    PubMed Central

    Kurse, Manish U.; Lipson, Hod

    2013-01-01

    Computationally efficient modeling of complex neuromuscular systems for dynamics and control simulations often requires accurate analytical expressions for moment arms over the entire range of motion. Conventionally, polynomial expressions are regressed from experimental data. But these polynomial regressions can fail to extrapolate, may require large datasets to train, are not robust to noise, and often have numerous free parameters. We present a novel method that simultaneously estimates both the form and parameter values of arbitrary analytical expressions for tendon excursions and moment arms over the entire range of motion from sparse datasets. This symbolic regression method based on genetic programming has been shown to find the appropriate form of mathematical expressions that capture the physics of mechanical systems. We demonstrate this method by applying it to (i) experimental data from a physical tendon-driven robotic system with arbitrarily routed multiarticular tendons and (ii) synthetic data from musculoskeletal models. We show it outperforms polynomial regressions in the amount of training data, ability to extrapolate, robustness to noise, and representation containing fewer parameters – all critical to realistic and efficient computational modeling of complex musculoskeletal systems. PMID:22410321

  17. Rough Atanassov's Intuitionistic Fuzzy Sets Model over Two Universes and Its Applications

    PubMed Central

    Luo, Shuqun

    2014-01-01

    Recently, much attention has been given to the rough set models based on two universes. And many rough set models based on two universes have been developed from different points of view. In this paper, a novel model, that is, rough Atanassov's intuitionistic fuzzy sets model over two different universes, is firstly proposed from Atanassov's intuitionistic point of view. We study some important properties of approximation operators and investigate the rough degree in the novel model. Furthermore, an illustrated example is employed to demonstrate the conceptual arguments of the model. Finally, rough Atanassov's intuitionistic fuzzy sets approach to decision is presented in the generalized approximation space over two universes by considering the problem about how to arrange patients to see the doctor reasonably, from which it can be found that the method is valuable and useful in real life. PMID:24959609

  18. Rough Atanassov's intuitionistic fuzzy sets model over two universes and its applications.

    PubMed

    Luo, Shuqun; Xu, Weihua

    2014-01-01

    Recently, much attention has been given to the rough set models based on two universes. And many rough set models based on two universes have been developed from different points of view. In this paper, a novel model, that is, rough Atanassov's intuitionistic fuzzy sets model over two different universes, is firstly proposed from Atanassov's intuitionistic point of view. We study some important properties of approximation operators and investigate the rough degree in the novel model. Furthermore, an illustrated example is employed to demonstrate the conceptual arguments of the model. Finally, rough Atanassov's intuitionistic fuzzy sets approach to decision is presented in the generalized approximation space over two universes by considering the problem about how to arrange patients to see the doctor reasonably, from which it can be found that the method is valuable and useful in real life.

  19. Two-phase electro-hydrodynamic flow modeling by a conservative level set model.

    PubMed

    Lin, Yuan

    2013-03-01

    The principles of electro-hydrodynamic (EHD) flow have been known for more than a century and have been adopted for various industrial applications, for example, fluid mixing and demixing. Analytical solutions of such EHD flow only exist in a limited number of scenarios, for example, predicting a small deformation of a single droplet in a uniform electric field. Numerical modeling of such phenomena can provide significant insights about EHDs multiphase flows. During the last decade, many numerical results have been reported to provide novel and useful tools of studying the multiphase EHD flow. Based on a conservative level set method, the proposed model is able to simulate large deformations of a droplet by a steady electric field, which is beyond the region of theoretic prediction. The model is validated for both leaky dielectrics and perfect dielectrics, and is found to be in excellent agreement with existing analytical solutions and numerical studies in the literature. Furthermore, simulations of the deformation of a water droplet in decyl alcohol in a steady electric field match better with published experimental data than the theoretical prediction for large deformations. Therefore the proposed model can serve as a practical and accurate tool for simulating two-phase EHD flow.

  20. Assessing effects of variation in global climate data sets on spatial predictions from climate envelope models

    USGS Publications Warehouse

    Romanach, Stephanie; Watling, James I.; Fletcher, Robert J.; Speroterra, Carolina; Bucklin, David N.; Brandt, Laura A.; Pearlstine, Leonard G.; Escribano, Yesenia; Mazzotti, Frank J.

    2014-01-01

    Climate change poses new challenges for natural resource managers. Predictive modeling of species–environment relationships using climate envelope models can enhance our understanding of climate change effects on biodiversity, assist in assessment of invasion risk by exotic organisms, and inform life-history understanding of individual species. While increasing interest has focused on the role of uncertainty in future conditions on model predictions, models also may be sensitive to the initial conditions on which they are trained. Although climate envelope models are usually trained using data on contemporary climate, we lack systematic comparisons of model performance and predictions across alternative climate data sets available for model training. Here, we seek to fill that gap by comparing variability in predictions between two contemporary climate data sets to variability in spatial predictions among three alternative projections of future climate. Overall, correlations between monthly temperature and precipitation variables were very high for both contemporary and future data. Model performance varied across algorithms, but not between two alternative contemporary climate data sets. Spatial predictions varied more among alternative general-circulation models describing future climate conditions than between contemporary climate data sets. However, we did find that climate envelope models with low Cohen's kappa scores made more discrepant spatial predictions between climate data sets for the contemporary period than did models with high Cohen's kappa scores. We suggest conservation planners evaluate multiple performance metrics and be aware of the importance of differences in initial conditions for spatial predictions from climate envelope models.

  1. Teaching generalization of purchasing skills across community settings to autistic youth using videotape modeling.

    PubMed

    Haring, T G; Kennedy, C H; Adams, M J; Pitts-Conway, V

    1987-01-01

    Three young autistic adults were trained to purchase items. Training was conducted in one setting with concurrent generalization probes taken in three community stores. Training in one setting failed to produce generalization to the three probe settings. Generalization training, which consisted of viewing videotapes of models who purchased items in the probe settings and answering questions about the models' responses, was then introduced. Training with the videotapes resulted in generalization to the three community stores. Results of the use of videotapes as a cost-effective means to program generalization in community training programs are discussed.

  2. The Late Eocene 187Os / 188Os excursion: Chemostratigraphy, cosmic dust flux and the Early Oligocene glaciation

    NASA Astrophysics Data System (ADS)

    Dalai, Tarun K.; Ravizza, Gregory E.; Peucker-Ehrenbrink, B.

    2006-01-01

    High resolution records (ca. 100 kyr) of Os isotope composition ( 187Os / 188Os) in bulk sediments from two tropical Pacific sites (ODP Sites 1218 and 1219) capture the complete Late Eocene 187Os / 188Os excursion and confirm that the Late Eocene 187Os / 188Os minimum, earlier reported by Ravizza and Peucker-Ehrenbrink [Earth Planet. Sci. Lett. 210 (2003) 151-165], is a global feature. Using the astronomically tuned age models available for these sites, it is suggested that the Late Eocene 187Os / 188Os minimum can be placed at 34.5 ± 0.1 Ma in the marine records. In addition, two other distinct features of the 187Os / 188Os excursion that are correlatable among sections are proposed as chemostratigraphic markers which can serve as age control points with a precision of ca. ± 0.1 Myr. We propose a speculative hypothesis that higher cosmic dust flux in the Late Eocene may have contributed to global cooling and Early Oligocene glaciation (Oi-1) by supplying bio-essential trace elements to the oceans and thereby resulting in higher ocean productivity, enhanced burial of organic carbon and draw down of atmospheric CO 2. To determine if the hypothesis that enhanced cosmic dust flux in the Late Eocene was a cause for the 187Os / 188Os excursion can be tested by using the paired bulk sediment and leachate Os isotope composition; 187Os / 188Os were also measured in sediment leachates. Results of analyses of leachates are inconsistent between the south Atlantic and the Pacific sites, and therefore do not yield a robust test of this hypothesis. Comparison of 187Os / 188Os records with high resolution benthic foraminiferal δ18O records across the Eocene-Oligocene transition suggests that 187Os flux to the oceans decreased during cooling and ice growth leading to the Oi-1 glaciation, whereas subsequent decay of ice-sheets and deglacial weathering drove seawater 187Os / 188Os to higher values. Although the precise timing and magnitude of these changes in weathering fluxes

  3. Evaluation of tricuspid annular plane systolic excursion measured with cardiac MRI in children with tetralogy of Fallot.

    PubMed

    Soslow, Jonathan H; Usoro, Emem; Wang, Li; Parra, David A

    2016-04-01

    Aneurysmal dilation of the right ventricular outflow tract complicates assessment of right ventricular function in patients with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is commonly used to estimate ejection fraction. We hypothesised that tricuspid annular plane systolic excursion measured by cardiac MRI approximates global and segmental right ventricular function, specifically right ventricular sinus ejection fraction, in children with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion was measured retrospectively on cardiac MRIs in 54 patients with repaired tetralogy of Fallot. Values were compared with right ventricular global, sinus, and infundibular ejection fractions. Tricuspid annular plane systolic excursion was indexed to body surface area, converted into a fractional value, and converted into published paediatric Z-scores. Tricuspid annular plane systolic excursion measurements had good agreement between observers. Right ventricular ejection fraction did not correlate with the absolute or indexed tricuspid annular plane systolic excursion and correlated weakly with fractional tricuspid annular plane systolic excursion (r=0.41 and p=0.002). Segmental right ventricular function did not appreciably improve correlation with any of the tricuspid annular plane systolic excursion measures. Paediatric Z-scores were unable to differentiate patients with normal and abnormal right ventricular function. Tricuspid annular plane systolic excursion measured by cardiac MRI correlates poorly with global and segmental right ventricular ejection fraction in children with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is an unreliable approximation of right ventricular function in this patient population.

  4. Experimental Errors in QSAR Modeling Sets: What We Can Do and What We Cannot Do.

    PubMed

    Zhao, Linlin; Wang, Wenyi; Sedykh, Alexander; Zhu, Hao

    2017-06-30

    Numerous chemical data sets have become available for quantitative structure-activity relationship (QSAR) modeling studies. However, the quality of different data sources may be different based on the nature of experimental protocols. Therefore, potential experimental errors in the modeling sets may lead to the development of poor QSAR models and further affect the predictions of new compounds. In this study, we explored the relationship between the ratio of questionable data in the modeling sets, which was obtained by simulating experimental errors, and the QSAR modeling performance. To this end, we used eight data sets (four continuous endpoints and four categorical endpoints) that have been extensively curated both in-house and by our collaborators to create over 1800 various QSAR models. Each data set was duplicated to create several new modeling sets with different ratios of simulated experimental errors (i.e., randomizing the activities of part of the compounds) in the modeling process. A fivefold cross-validation process was used to evaluate the modeling performance, which deteriorates when the ratio of experimental errors increases. All of the resulting models were also used to predict external sets of new compounds, which were excluded at the beginning of the modeling process. The modeling results showed that the compounds with relatively large prediction errors in cross-validation processes are likely to be those with simulated experimental errors. However, after removing a certain number of compounds with large prediction errors in the cross-validation process, the external predictions of new compounds did not show improvement. Our conclusion is that the QSAR predictions, especially consensus predictions, can identify compounds with potential experimental errors. But removing those compounds by the cross-validation procedure is not a reasonable means to improve model predictivity due to overfitting.

  5. Experimental Errors in QSAR Modeling Sets: What We Can Do and What We Cannot Do

    PubMed Central

    2017-01-01

    Numerous chemical data sets have become available for quantitative structure–activity relationship (QSAR) modeling studies. However, the quality of different data sources may be different based on the nature of experimental protocols. Therefore, potential experimental errors in the modeling sets may lead to the development of poor QSAR models and further affect the predictions of new compounds. In this study, we explored the relationship between the ratio of questionable data in the modeling sets, which was obtained by simulating experimental errors, and the QSAR modeling performance. To this end, we used eight data sets (four continuous endpoints and four categorical endpoints) that have been extensively curated both in-house and by our collaborators to create over 1800 various QSAR models. Each data set was duplicated to create several new modeling sets with different ratios of simulated experimental errors (i.e., randomizing the activities of part of the compounds) in the modeling process. A fivefold cross-validation process was used to evaluate the modeling performance, which deteriorates when the ratio of experimental errors increases. All of the resulting models were also used to predict external sets of new compounds, which were excluded at the beginning of the modeling process. The modeling results showed that the compounds with relatively large prediction errors in cross-validation processes are likely to be those with simulated experimental errors. However, after removing a certain number of compounds with large prediction errors in the cross-validation process, the external predictions of new compounds did not show improvement. Our conclusion is that the QSAR predictions, especially consensus predictions, can identify compounds with potential experimental errors. But removing those compounds by the cross-validation procedure is not a reasonable means to improve model predictivity due to overfitting. PMID:28691113

  6. Basic priority rating model 2.0: current applications for priority setting in health promotion practice.

    PubMed

    Neiger, Brad L; Thackeray, Rosemary; Fagen, Michael C

    2011-03-01

    Priority setting is an important component of systematic planning in health promotion and also factors into the development of a comprehensive evaluation plan. The basic priority rating (BPR) model was introduced more than 50 years ago and includes criteria that should be considered in any priority setting approach (i.e., use of predetermined criteria, standardized comparisons, and a rubric that controls bias). Although the BPR model has provided basic direction in priority setting, it does not represent the broad array of data currently available to decision makers. Elements in the model also give more weight to the impact of communicable diseases compared with chronic diseases. For these reasons, several modifications are recommended to improve the BPR model and to better assist health promotion practitioners in the priority setting process. The authors also suggest a new name, BPR 2.0, to represent this revised model.

  7. A Data Preprocessing Algorithm for Classification Model Based On Rough Sets

    NASA Astrophysics Data System (ADS)

    Xiang-wei, Li; Yian-fang, Qi

    Aimed to solve the limitation of abundant data to constructing classification modeling in data mining, the paper proposed a novel effective preprocessing algorithm based on rough sets. Firstly, we construct the relation Information System using original data sets. Secondly, make use of attribute reduction theory of Rough sets to produce the Core of Information System. Core is the most important and necessary information which cannot reduce in original Information System. So it can get a same effect as original data sets to data analysis, and can construct classification modeling using it. Thirdly, construct indiscernibility matrix using reduced Information System, and finally, get the classification of original data sets. Compared to existing techniques, the developed algorithm enjoy following advantages: (1) avoiding the abundant data in follow-up data processing, and (2) avoiding large amount of computation in whole data mining process. (3) The results become more effective because of introducing the attributes reducing theory of Rough Sets.

  8. Methods of artificial enlargement of the training set for statistical shape models.

    PubMed

    Koikkalainen, Juha; Tölli, Tuomas; Lauerma, Kirsi; Antila, Kari; Mattila, Elina; Lilja, Mikko; Lötjönen, Jyrki

    2008-11-01

    Due to the small size of training sets, statistical shape models often over-constrain the deformation in medical image segmentation. Hence, artificial enlargement of the training set has been proposed as a solution for the problem to increase the flexibility of the models. In this paper, different methods were evaluated to artificially enlarge a training set. Furthermore, the objectives were to study the effects of the size of the training set, to estimate the optimal number of deformation modes, to study the effects of different error sources, and to compare different deformation methods. The study was performed for a cardiac shape model consisting of ventricles, atria, and epicardium, and built from magnetic resonance (MR) volume images of 25 subjects. Both shape modeling and image segmentation accuracies were studied. The objectives were reached by utilizing different training sets and datasets, and two deformation methods. The evaluation proved that artificial enlargement of the training set improves both the modeling and segmentation accuracy. All but one enlargement techniques gave statistically significantly (p < 0.05) better segmentation results than the standard method without enlargement. The two best enlargement techniques were the nonrigid movement technique and the technique that combines principal component analysis (PCA) and finite element model (FEM). The optimal number of deformation modes was found to be near 100 modes in our application. The active shape model segmentation gave better segmentation accuracy than the one based on the simulated annealing optimization of the model weights.

  9. Engaging students in research learning experiences through hydrology field excursions and projects

    NASA Astrophysics Data System (ADS)

    Ewen, T.; Seibert, J.

    2014-12-01

    One of the best ways to engage students and instill enthusiasm for hydrology is to expose them to hands-on learning. A focus on hydrology field research can be used to develop context-rich and active learning, and help solidify idealized learning where students are introduced to individual processes through textbook examples, often neglecting process interactions and an appreciation for the complexity of the system. We introduced a field course where hydrological measurement techniques are used to study processes such as snow hydrology and runoff generation, while also introducing students to field research and design of their own field project. In the field projects, students design a low-budget experiment with the aim of going through the different steps of a 'real' scientific project, from formulating the research question to presenting their results. In one of the field excursions, students make discharge measurements in several alpine streams with a salt tracer to better understand the spatial characteristics of an alpine catchment, where source waters originate and how they contribute to runoff generation. Soil moisture measurements taken by students in this field excursion were used to analyze spatial soil moisture patterns in the alpine catchment and subsequently used in a publication. Another field excursion repeats a published experiment, where preferential soil flow paths are studied using a tracer and compared to previously collected data. For each field excursion, observational data collected by the students is uploaded to an online database we developed, which also allows students to retrieve data from past excursions to further analyze and compare their data. At each of the field sites, weather stations were installed and a webviewer allows access to realtime data from data loggers, allowing students to explore how processes relate to climatic conditions. With in-house film expertise, these field excursions were also filmed and short virtual

  10. Diverse Data Sets Can Yield Reliable Information through Mechanistic Modeling: Salicylic Acid Clearance

    PubMed Central

    Raymond, G. M.; Bassingthwaighte, J. B.

    2016-01-01

    This is a practical example of a powerful research strategy: putting together data from studies covering a diversity of conditions can yield a scientifically sound grasp of the phenomenon when the individual observations failed to provide definitive understanding. The rationale is that defining a realistic, quantitative, explanatory hypothesis for the whole set of studies, brings about a “consilience” of the often competing hypotheses considered for individual data sets. An internally consistent conjecture linking multiple data sets simultaneously provides stronger evidence on the characteristics of a system than does analysis of individual data sets limited to narrow ranges of conditions. Our example examines three very different data sets on the clearance of salicylic acid from humans: a high concentration set from aspirin overdoses; a set with medium concentrations from a research study on the influences of the route of administration and of sex on the clearance kinetics, and a set on low dose aspirin for cardiovascular health. Three models were tested: (1) a first order reaction, (2) a Michaelis-Menten (M-M) approach, and (3) an enzyme kinetic model with forward and backward reactions. The reaction rates found from model 1 were distinctly different for the three data sets, having no commonality. The M-M model 2 fitted each of the three data sets but gave a reliable estimates of the Michaelis constant only for the medium level data (Km = 24±5.4 mg/L); analyzing the three data sets together with model 2 gave Km = 18±2.6 mg/L. (Estimating parameters using larger numbers of data points in an optimization increases the degrees of freedom, constraining the range of the estimates). Using the enzyme kinetic model (3) increased the number of free parameters but nevertheless improved the goodness of fit to the combined data sets, giving tighter constraints, and a lower estimated Km = 14.6±2.9 mg/L, demonstrating that fitting diverse data sets with a single model

  11. Diverse Data Sets Can Yield Reliable Information through Mechanistic Modeling: Salicylic Acid Clearance.

    PubMed

    Raymond, G M; Bassingthwaighte, J B

    This is a practical example of a powerful research strategy: putting together data from studies covering a diversity of conditions can yield a scientifically sound grasp of the phenomenon when the individual observations failed to provide definitive understanding. The rationale is that defining a realistic, quantitative, explanatory hypothesis for the whole set of studies, brings about a "consilience" of the often competing hypotheses considered for individual data sets. An internally consistent conjecture linking multiple data sets simultaneously provides stronger evidence on the characteristics of a system than does analysis of individual data sets limited to narrow ranges of conditions. Our example examines three very different data sets on the clearance of salicylic acid from humans: a high concentration set from aspirin overdoses; a set with medium concentrations from a research study on the influences of the route of administration and of sex on the clearance kinetics, and a set on low dose aspirin for cardiovascular health. Three models were tested: (1) a first order reaction, (2) a Michaelis-Menten (M-M) approach, and (3) an enzyme kinetic model with forward and backward reactions. The reaction rates found from model 1 were distinctly different for the three data sets, having no commonality. The M-M model 2 fitted each of the three data sets but gave a reliable estimates of the Michaelis constant only for the medium level data (Km = 24±5.4 mg/L); analyzing the three data sets together with model 2 gave Km = 18±2.6 mg/L. (Estimating parameters using larger numbers of data points in an optimization increases the degrees of freedom, constraining the range of the estimates). Using the enzyme kinetic model (3) increased the number of free parameters but nevertheless improved the goodness of fit to the combined data sets, giving tighter constraints, and a lower estimated Km = 14.6±2.9 mg/L, demonstrating that fitting diverse data sets with a single model

  12. Applicability domains for classification problems: benchmarking of distance to models for AMES mutagenicity set

    EPA Science Inventory

    For QSAR and QSPR modeling of biological and physicochemical properties, estimating the accuracy of predictions is a critical problem. The “distance to model” (DM) can be defined as a metric that defines the similarity between the training set molecules and the test set compound ...

  13. What Time Is Sunrise? Revisiting the Refraction Component of Sunrise/set Prediction Models

    NASA Astrophysics Data System (ADS)

    Wilson, Teresa; Bartlett, Jennifer L.; Hilton, James Lindsay

    2017-01-01

    Algorithms that predict sunrise and sunset times currently have an error of one to four minutes at mid-latitudes (0° - 55° N/S) due to limitations in the atmospheric models they incorporate. At higher latitudes, slight changes in refraction can cause significant discrepancies, even including difficulties determining when the Sun appears to rise or set. While different components of refraction are known, how they affect predictions of sunrise/set has not yet been quantified. A better understanding of the contributions from temperature profile, pressure, humidity, and aerosols could significantly improve the standard prediction. We present a sunrise/set calculator that interchanges the refraction component by varying the refraction model. We then compare these predictions with data sets of observed rise/set times to create a better model. Sunrise/set times and meteorological data from multiple locations will be necessary for a thorough investigation of the problem. While there are a few data sets available, we will also begin collecting this data using smartphones as part of a citizen science project. The mobile application for this project will be available in the Google Play store. Data analysis will lead to more complete models that will provide more accurate rise/set times for the benefit of astronomers, navigators, and outdoorsmen everywhere.

  14. USE OF ROUGH SETS AND SPECTRAL DATA FOR BUILDING PREDICTIVE MODELS OF REACTION RATE CONSTANTS

    EPA Science Inventory

    A model for predicting the log of the rate constants for alkaline hydrolysis of organic esters has been developed with the use of gas-phase min-infrared library spectra and a rule-building software system based on the mathematical theory of rough sets. A diverse set of 41 esters ...

  15. Diagnostic Profiles: A Standard Setting Method for Use with a Cognitive Diagnostic Model

    ERIC Educational Resources Information Center

    Skaggs, Gary; Hein, Serge F.; Wilkins, Jesse L. M.

    2016-01-01

    This article introduces the Diagnostic Profiles (DP) standard setting method for setting a performance standard on a test developed from a cognitive diagnostic model (CDM), the outcome of which is a profile of mastered and not-mastered skills or attributes rather than a single test score. In the DP method, the key judgment task for panelists is a…

  16. Modeling the Effects of Choice-Set Size on the Processing of Letters and Words

    ERIC Educational Resources Information Center

    Rouder, Jeffrey N.

    2004-01-01

    Letters and words are better identified when there are fewer available choices. How do readers use choice-set restrictions? By analyzing new experimental data and previously reported data, the author shows that Bayes theorem-based models overestimate readers' use of choice-set restrictions. This result is discordant with choice-similarity models…

  17. USE OF ROUGH SETS AND SPECTRAL DATA FOR BUILDING PREDICTIVE MODELS OF REACTION RATE CONSTANTS

    EPA Science Inventory

    A model for predicting the log of the rate constants for alkaline hydrolysis of organic esters has been developed with the use of gas-phase min-infrared library spectra and a rule-building software system based on the mathematical theory of rough sets. A diverse set of 41 esters ...

  18. Applicability domains for classification problems: benchmarking of distance to models for AMES mutagenicity set

    EPA Science Inventory

    For QSAR and QSPR modeling of biological and physicochemical properties, estimating the accuracy of predictions is a critical problem. The “distance to model” (DM) can be defined as a metric that defines the similarity between the training set molecules and the test set compound ...

  19. Standard setting with dichotomous and constructed response items: some Rasch model approaches.

    PubMed

    MacCann, Robert G

    2009-01-01

    Using real data comprising responses to both dichotomously scored and constructed response items, this paper shows how Rasch modeling may be used to facilitate standard-setting. The modeling uses Andrich's Extended Logistic Model, which is incorporated into the RUMM software package. After a review of the fundamental equations of the model, an application to Bookmark standard setting is given, showing how to calculate the bookmark difficulty location (BDL) for both dichomotous items and tests containing a mixture of item types. An example showing how the bookmark is set is also discussed. The Rasch model is then applied in various ways to the Angoff standard-setting methods. In the first Angoff approach, the judges' item ratings are compared to Rasch model expected scores, allowing the judges to find items where their ratings differ significantly from the Rasch model values. In the second Angoff approach, the distribution of item ratings are converted to a distribution of possible cutscores, from which a final cutscore may be selected. In the third Angoff approach, the Rasch model provides a comprehensive information set to the judges. For every total score on the test, the model provides a column of item ratings (expected scores) for the ability associated with the total score. The judges consider each column of item ratings as a whole and select the column that best fits the expected pattern of responses of a marginal candidate. The total score corresponding to the selected column is then the performance band cutscore.

  20. Paleointensity and 40Ar/39Ar geochronology of basalts at Gamarri, Ethiopia: Correlation with the Réunion subchron and Huckleberry Ridge excursion?

    NASA Astrophysics Data System (ADS)

    Kindley, C.; Macho, A.; Tsegaye, M. A.; Feinberg, J. M.; Singer, B. S.; Jicha, B. R.; Brown, M. C.; Birke, T. K.

    2012-12-01

    several excursions occurring between ~2.2 and ~2.5 Ma. These excursions have been observed within records from ODP 982 (Channell & Guyodo, 2004) and IODP U1314 (Ohno et al., 2012), as well as within the GPTS as cryptochron C2r.2r-1 (originally dated as 2.420 to 2.441 Ma by Cande & Kent, 1995). Thus, we no longer interpret the excursion recorded in the lower portion of the Gamarri section to be part of the Réunion subchron and recommend that it be omitted from efforts to construct integrated global field models across the Huckleberry Ridge excursion and Réunion subchron.

  1. Validation of tsunami inundation model TUNA-RP using OAR-PMEL-135 benchmark problem set

    NASA Astrophysics Data System (ADS)

    Koh, H. L.; Teh, S. Y.; Tan, W. K.; Kh'ng, X. Y.

    2017-05-01

    A standard set of benchmark problems, known as OAR-PMEL-135, is developed by the US National Tsunami Hazard Mitigation Program for tsunami inundation model validation. Any tsunami inundation model must be tested for its accuracy and capability using this standard set of benchmark problems before it can be gainfully used for inundation simulation. The authors have previously developed an in-house tsunami inundation model known as TUNA-RP. This inundation model solves the two-dimensional nonlinear shallow water equations coupled with a wet-dry moving boundary algorithm. This paper presents the validation of TUNA-RP against the solutions provided in the OAR-PMEL-135 benchmark problem set. This benchmark validation testing shows that TUNA-RP can indeed perform inundation simulation with accuracy consistent with that in the tested benchmark problem set.

  2. A Variable Precision Covering-Based Rough Set Model Based on Functions

    PubMed Central

    Zhu, Yanqing

    2014-01-01

    Classical rough set theory is a technique of granular computing for handling the uncertainty, vagueness, and granularity in information systems. Covering-based rough sets are proposed to generalize this theory for dealing with covering data. By introducing a concept of misclassification rate functions, an extended variable precision covering-based rough set model is proposed in this paper. In addition, we define the f-lower and f-upper approximations in terms of neighborhoods in the extended model and study their properties. Particularly, two coverings with the same reductions are proved to generate the same f-lower and f-upper approximations. Finally, we discuss the relationships between the new model and some other variable precision rough set models. PMID:25177715

  3. Integrating gene set analysis and nonlinear predictive modeling of disease phenotypes using a Bayesian multitask formulation.

    PubMed

    Gönen, Mehmet

    2016-12-13

    Identifying molecular signatures of disease phenotypes is studied using two mainstream approaches: (i) Predictive modeling methods such as linear classification and regression algorithms are used to find signatures predictive of phenotypes from genomic data, which may not be robust due to limited sample size or highly correlated nature of genomic data. (ii) Gene set analysis methods are used to find gene sets on which phenotypes are linearly dependent by bringing prior biological knowledge into the analysis, which may not capture more complex nonlinear dependencies. Thus, formulating an integrated model of gene set analysis and nonlinear predictive modeling is of great practical importance. In this study, we propose a Bayesian binary classification framework to integrate gene set analysis and nonlinear predictive modeling. We then generalize this formulation to multitask learning setting to model multiple related datasets conjointly. Our main novelty is the probabilistic nonlinear formulation that enables us to robustly capture nonlinear dependencies between genomic data and phenotype even with small sample sizes. We demonstrate the performance of our algorithms using repeated random subsampling validation experiments on two cancer and two tuberculosis datasets by predicting important disease phenotypes from genome-wide gene expression data. We are able to obtain comparable or even better predictive performance than a baseline Bayesian nonlinear algorithm and to identify sparse sets of relevant genes and gene sets on all datasets. We also show that our multitask learning formulation enables us to further improve the generalization performance and to better understand biological processes behind disease phenotypes.

  4. Introduction to the development and validation of predictive biomarker models from high-throughput data sets.

    PubMed

    Deng, Xutao; Campagne, Fabien

    2010-01-01

    High-throughput technologies can routinely assay biological or clinical samples and produce wide data sets where each sample is associated with tens of thousands of measurements. Such data sets can be mined to discover biomarkers and develop statistical models capable of predicting an endpoint of interest from data measured in the samples. The field of biomarker model development combines methods from statistics and machine learning to develop and evaluate predictive biomarker models. In this chapter, we discuss the computational steps involved in the development of biomarker models designed to predict information about individual samples and review approaches often used to implement each step. A practical example of biomarker model development in a large gene expression data set is presented. This example leverages BDVal, a suite of biomarker model development programs developed as an open-source project (see http://bdval.org /).

  5. Effects of Visual Display on Joint Excursions Used to Play Virtual Dodgeball

    PubMed Central

    France, Christopher R; Applegate, Megan E; Leitkam, Samuel T; Pidcoe, Peter E; Walkowski, Stevan

    2016-01-01

    Background Virtual reality (VR) interventions hold great potential for rehabilitation as commercial systems are becoming more affordable and can be easily applied to both clinical and home settings. Objective In this study, we sought to determine how differences in the VR display type can influence motor behavior, cognitive load, and participant engagement. Methods Movement patterns of 17 healthy young adults (8 female, 9 male) were examined during games of Virtual Dodgeball presented on a three-dimensional television (3DTV) and a head-mounted display (HMD). The participant’s avatar was presented from a third-person perspective on a 3DTV and from a first-person perspective on an HMD. Results Examination of motor behavior revealed significantly greater excursions of the knee (P=.003), hip (P<.001), spine (P<.001), shoulder (P=.001), and elbow (P=.026) during HMD versus 3DTV gameplay, resulting in significant differences in forward (P=.003) and downward (P<.001) displacement of the whole-body center of mass. Analyses of cognitive load and engagement revealed that relative to 3DTV, participants indicated that HMD gameplay resulted in greater satisfaction with overall performance and was less frustrating (P<.001). There were no significant differences noted for mental demand. Conclusions Differences in visual display type and participant perspective influence how participants perform in Virtual Dodgeball. Because VR use within rehabilitation settings is often designed to help restore movement following orthopedic or neurologic injury, these findings provide an important caveat regarding the need to consider the potential influence of presentation format and perspective on motor behavior. PMID:27634561

  6. Increased musculoskeletal stiffness during load carriage at increasing walking speeds maintains constant vertical excursion of the body center of mass.

    PubMed

    Holt, Kenneth G; Wagenaar, Robert C; LaFiandra, Michael E; Kubo, Masayoshi; Obusek, John P

    2003-04-01

    The primary objective of this research was to determine changes in body and joint stiffness parameters and kinematics of the knee and body center of mass (COM), that result from wearing a backpack (BP) with a 40% body weight load at increasing speeds of walking. It was hypothesized that there would be speed and load-related increases in stiffness that would prevent significant deviations in the COM trajectory and in lower-extremity joint angles. Three independent biomechanical models employing kinematic data were used to estimate global lower-extremity stiffness, vertical stiffness and knee joint rotational stiffness in the sagittal plane during walking on a treadmill at speeds of 0.6-1.6 ms(-1) in 0.2 ms(-1) increments in BP and no backpack conditions. Kinematic data were collected using an Optotrak, three-dimensional motion analysis system. Knee angles and vertical excursion of the COM during the compression (loading phase) increased as a function of speed but not load. All three estimates of stiffness showed significant increases as a function of both speed and load. Significant interaction effects indicated a convergence of load-related stiffness values at lower speeds. Results suggested that increases in muscle-mediated stiffness are used to maintain a constant vertical excursion of the COM under load across the speeds tested, and thereby limit increases in metabolic cost that would occur if the COM would travel through greater vertical range of motion.

  7. Influence of heat treatment excursion on critical current and residual resistivity ratio of ITER Nb3Sn strands

    NASA Astrophysics Data System (ADS)

    Lu, J.; McGuire, D. R.; Hill, S.; Niu, R.; Chan, K.; Martovetsky, N. N.

    2017-07-01

    Heat treatment is critically important to the performance of Nb3Sn superconducting strands. For very large Nb3Sn magnet coils, such as the International Thermonuclear Experimental Reactor (ITER) central solenoid (CS) coils, heat treatment carries the risk of temperature and time excursion, which may result in performance degradation. Therefore, it is prudent to study the effect of possible excursion on Nb3Sn performance. In this study, Nb3Sn strands used for ITER CS coils are heat treated at different temperatures for different times. Their critical current, residual resistance ratio and hysteresis losses are measured. It is found that in the range we studied, critical current and hysteresis losses do not change significantly. Residual resistance ratio, however, decreases with increasing heat treatment temperature and time. This is attributed to the diffusion of metallic elements from the plated Cr layer to the copper stabilizer. Based on a model of metallic elements diffusion, a numerical code is developed to predict residual resistance ratio as a function of heat treatment temperature and time.

  8. Multi-proxy identification of the Laschamp geomagnetic field excursion in Lake Pupuke, New Zealand

    NASA Astrophysics Data System (ADS)

    Nilsson, Andreas; Muscheler, Raimund; Snowball, Ian; Aldahan, Ala; Possnert, Göran; Augustinus, Paul; Atkin, Daniel; Stephens, Tom

    2011-11-01

    We present palaeomagnetic and cosmogenic radionuclide records of the Laschamp geomagnetic excursion in Lake Pupuke, a maar lake in Auckland, New Zealand. Laschamp was identified by a combination of relative palaeointensity, 10Be and 14C data from the lake sediments and represents the first such record from the Southern Hemisphere. Despite the high organic carbon content, which causes relatively weak natural remanent magnetisations, the geomagnetic intensity minimum associated with the Laschamp excursion is identifiable as a relative palaeointensity minimum that is synchronous with (i) a peak in 10Be concentration and (ii) an anomaly in Δ 14C. The Lake Pupuke time scale, provided by 14C data calibrated with INTCAL09, places the 10Be maximum at the same time as a 10Be maximum in Greenland ice cores when secured to the GICC05 time scale. The central age of the Laschamp geomagnetic excursion in Lake Pupuke as defined by the 10Be prediction peak is c. 41 kyr, which confirms its global application as a palaeomagnetic isochron. Anomalous palaeomagnetic directional data at c. 32 kyr in the Lake Pupuke sediments may represent the Mono Lake geomagnetic excursion, but tephra layers caused by frequent eruptions in the Auckland volcanic field during this excursion probably disrupted the palaeointensity signal. The study highlights the value of combining traditional palaeomagnetic methods with measurements of cosmogenic radionuclides in the quest for accurate and precise geochronologies during MIS3, a time of rapid global climate change.

  9. Relation of Phanerozoic stable isotope excursions to climate, bacterial metabolism, and major extinctions

    PubMed Central

    Stanley, Steven M.

    2010-01-01

    Conspicuous global stable carbon isotope excursions that are recorded in marine sedimentary rocks of Phanerozoic age and were associated with major extinctions have generally paralleled global stable oxygen isotope excursions. All of these phenomena are therefore likely to share a common origin through global climate change. Exceptional patterns for carbon isotope excursions resulted from massive carbon burial during warm intervals of widespread marine anoxic conditions. The many carbon isotope excursions that parallel those for oxygen isotopes can to a large degree be accounted for by the Q10 pattern of respiration for bacteria: As temperature changed along continental margins, where ∼90% of marine carbon burial occurs today, rates of remineralization of isotopically light carbon must have changed exponentially. This would have reduced organic carbon burial during global warming and increased it during global cooling. Also contributing to the δ13C excursions have been release and uptake of methane by clathrates, the positive correlation between temperature and degree of fractionation of carbon isotopes by phytoplankton at temperatures below ∼15°, and increased phytoplankton productivity during “icehouse” conditions. The Q10 pattern for bacteria and climate-related changes in clathrate volume represent positive feedbacks for climate change. PMID:21041682

  10. Tendon and fascial structure contributions to knee muscle excursions and knee joint displacement.

    PubMed

    Snoeck, O; Beyer, B; Feipel, V; Salvia, P; Sterckx, J-L; Rooze, M; Van Sint Jan, S

    2014-11-01

    Semitendinosus and gracilis muscles whose tendons are used in surgical reconstruction of the anterior cruciate ligament maintain their contractile ability, and a limited decrease of hamstring muscles force is observed postoperatively despite important changes. The goal was to quantify the influence of the myofascial structures on excursions and moment arms of knee muscles to attempt explaining the above-mentioned post-surgical observations. Hamstring harvesting procedures were performed by a senior orthopaedic surgeon on seven lower limbs from fresh-frozen specimens. Femoro-tibial kinematics and tendons excursion were simultaneously recorded at each steps of the surgery. No significant difference was demonstrated for excursions and moment arms after tenotomies and gracilis tendon harvesting (P≥0.05). The first significant semitendinosus excursion (P<1.17×10(-4)) and moment arm (P<6.88×10(-5)) decrease was observed after semitendinosus tendon harvesting (46% of the initial excursion). Gracilis and semitendinosus myofascial pathway is crucial for force transmission towards the knee joint. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Relation of Phanerozoic stable isotope excursions to climate, bacterial metabolism, and major extinctions.

    PubMed

    Stanley, Steven M

    2010-11-09

    Conspicuous global stable carbon isotope excursions that are recorded in marine sedimentary rocks of Phanerozoic age and were associated with major extinctions have generally paralleled global stable oxygen isotope excursions. All of these phenomena are therefore likely to share a common origin through global climate change. Exceptional patterns for carbon isotope excursions resulted from massive carbon burial during warm intervals of widespread marine anoxic conditions. The many carbon isotope excursions that parallel those for oxygen isotopes can to a large degree be accounted for by the Q10 pattern of respiration for bacteria: As temperature changed along continental margins, where ∼90% of marine carbon burial occurs today, rates of remineralization of isotopically light carbon must have changed exponentially. This would have reduced organic carbon burial during global warming and increased it during global cooling. Also contributing to the δ(13)C excursions have been release and uptake of methane by clathrates, the positive correlation between temperature and degree of fractionation of carbon isotopes by phytoplankton at temperatures below ∼15°, and increased phytoplankton productivity during "icehouse" conditions. The Q10 pattern for bacteria and climate-related changes in clathrate volume represent positive feedbacks for climate change.

  12. Habitat Demonstration Unit (HDU) Pressurized Excursion Module (PEM) Systems Integration Strategy

    NASA Technical Reports Server (NTRS)

    Gill, Tracy; Merbitz, Jerad; Kennedy, Kriss; Tri, Terry; Toups, Larry; Howe, A. Scott

    2011-01-01

    The Habitat Demonstration Unit (HDU) project team constructed an analog prototype lunar surface laboratory called the Pressurized Excursion Module (PEM). The prototype unit subsystems were integrated in a short amount of time, utilizing a rapid prototyping approach that brought together over 20 habitation-related technologies from a variety of NASA centers. This paper describes the system integration strategies and lessons learned, that allowed the PEM to be brought from paper design to working field prototype using a multi-center team. The system integration process was based on a rapid prototyping approach. Tailored design review and test and integration processes facilitated that approach. The use of collaboration tools including electronic tools as well as documentation enabled a geographically distributed team take a paper concept to an operational prototype in approximately one year. One of the major tools used in the integration strategy was a coordinated effort to accurately model all the subsystems using computer aided design (CAD), so conflicts were identified before physical components came together. A deliberate effort was made following the deployment of the HDU PEM for field operations to collect lessons learned to facilitate process improvement and inform the design of future flight or analog versions of habitat systems. Significant items within those lessons learned were limitations with the CAD integration approach and the impact of shell design on flexibility of placing systems within the HDU shell.

  13. Joint Clustering and Component Analysis of Correspondenceless Point Sets: Application to Cardiac Statistical Modeling.

    PubMed

    Gooya, Ali; Lekadir, Karim; Alba, Xenia; Swift, Andrew J; Wild, Jim M; Frangi, Alejandro F

    2015-01-01

    Construction of Statistical Shape Models (SSMs) from arbitrary point sets is a challenging problem due to significant shape variation and lack of explicit point correspondence across the training data set. In medical imaging, point sets can generally represent different shape classes that span healthy and pathological exemplars. In such cases, the constructed SSM may not generalize well, largely because the probability density function (pdf) of the point sets deviates from the underlying assumption of Gaussian statistics. To this end, we propose a generative model for unsupervised learning of the pdf of point sets as a mixture of distinctive classes. A Variational Bayesian (VB) method is proposed for making joint inferences on the labels of point sets, and the principal modes of variations in each cluster. The method provides a flexible framework to handle point sets with no explicit point-to-point correspondences. We also show that by maximizing the marginalized likelihood of the model, the optimal number of clusters of point sets can be determined. We illustrate this work in the context of understanding the anatomical phenotype of the left and right ventricles in heart. To this end, we use a database containing hearts of healthy subjects, patients with Pulmonary Hypertension (PH), and patients with Hypertrophic Cardiomyopathy (HCM). We demonstrate that our method can outperform traditional PCA in both generalization and specificity measures.

  14. An interactive environment for the analysis of large Earth observation and model data sets

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.; Walsh, John E.; Wilhelmson, Robert B.

    1993-01-01

    We propose to develop an interactive environment for the analysis of large Earth science observation and model data sets. We will use a standard scientific data storage format and a large capacity (greater than 20 GB) optical disk system for data management; develop libraries for coordinate transformation and regridding of data sets; modify the NCSA X Image and X DataSlice software for typical Earth observation data sets by including map transformations and missing data handling; develop analysis tools for common mathematical and statistical operations; integrate the components described above into a system for the analysis and comparison of observations and model results; and distribute software and documentation to the scientific community.

  15. An interactive environment for the analysis of large Earth observation and model data sets

    NASA Technical Reports Server (NTRS)

    Bowman, Kenneth P.; Walsh, John E.; Wilhelmson, Robert B.

    1992-01-01

    We propose to develop an interactive environment for the analysis of large Earth science observation and model data sets. We will use a standard scientific data storage format and a large capacity (greater than 20 GB) optical disk system for data management; develop libraries for coordinate transformation and regridding of data sets; modify the NCSA X Image and X Data Slice software for typical Earth observation data sets by including map transformations and missing data handling; develop analysis tools for common mathematical and statistical operations; integrate the components described above into a system for the analysis and comparison of observations and model results; and distribute software and documentation to the scientific community.

  16. Validation of the U.S. NRC coupled code system TRITON/TRACE/PARCS with the special power excursion reactor test III (SPERT III)

    SciTech Connect

    Wang, R. C.; Xu, Y.; Downar, T.; Hudson, N.

    2012-07-01

    The Special Power Excursion Reactor Test III (SPERT III) was a series of reactivity insertion experiments conducted in the 1950's. This paper describes the validation of the U.S. NRC Coupled Code system TRITON/PARCS/TRACE to simulate reactivity insertion accidents (RIA) by using several of the SPERT III tests. The work here used the SPERT III E-core configuration tests in which the RIA was initiated by ejecting a control rod. The resulting super-prompt reactivity excursion and negative reactivity feedback produced the familiar bell shaped power increase and decrease. The energy deposition during such a power peak has important safety consequences and provides validation basis for core coupled multi-physics codes. The transients of five separate tests are used to benchmark the PARCS/TRACE coupled code. The models were thoroughly validated using the original experiment documentation. (authors)

  17. Robust autonomous model learning from 2D and 3D data sets.

    PubMed

    Langs, Georg; Donner, René; Peloschek, Philipp; Bischof, Horst

    2007-01-01

    In this paper we propose a weakly supervised learning algorithm for appearance models based on the minimum description length (MDL) principle. From a set of training images or volumes depicting examples of an anatomical structure, correspondences for a set of landmarks are established by group-wise registration. The approach does not require any annotation. In contrast to existing methods no assumptions about the topology of the data are made, and the topology can change throughout the data set. Instead of a continuous representation of the volumes or images, only sparse finite sets of interest points are used to represent the examples during optimization. This enables the algorithm to efficiently use distinctive points, and to handle texture variations robustly. In contrast to standard elasticity based deformation constraints the MDL criterion accounts for systematic deformations typical for training sets stemming from medical image data. Experimental results are reported for five different 2D and 3D data sets.

  18. Developing a Suitable Model for Water Uptake for Biodegradable Polymers Using Small Training Sets

    PubMed Central

    Valenzuela, Loreto M.; Knight, Doyle D.; Kohn, Joachim

    2016-01-01

    Prediction of the dynamic properties of water uptake across polymer libraries can accelerate polymer selection for a specific application. We first built semiempirical models using Artificial Neural Networks and all water uptake data, as individual input. These models give very good correlations (R2 > 0.78 for test set) but very low accuracy on cross-validation sets (less than 19% of experimental points within experimental error). Instead, using consolidated parameters like equilibrium water uptake a good model is obtained (R2 = 0.78 for test set), with accurate predictions for 50% of tested polymers. The semiempirical model was applied to the 56-polymer library of L-tyrosine-derived polyarylates, identifying groups of polymers that are likely to satisfy design criteria for water uptake. This research demonstrates that a surrogate modeling effort can reduce the number of polymers that must be synthesized and characterized to identify an appropriate polymer that meets certain performance criteria. PMID:27200091

  19. Evaluation of sleeve-pile set models used in docking jacket operation simulation

    SciTech Connect

    Cyranka, C.; Mourelle, M.M.; Ebecken, N.F.F.

    1995-12-31

    This work deals with the behavior of sleeve-pile set models used in the simulation of docking jacket operations. The adopted strategy involves the comparison of three-dimensional dynamic analysis with complete models, where docking pile and marine soil are considered. This dynamic analysis is performed in the time domain, including all the environmental loads and ship motions, using a substructure technique. The main discussion is focused in appropriate modeling the sleeve-pile set. Two propositions were examined: in the first one, the nonlinear docking spring takes into account the sleeve, pile and nonlinear soil contributions; in the second, the docking sleeve characteristics were added to the jacket model. To reach the objectives a real docking operation case was selected. A typical Campos Basin jacket was modeled with fine discretization of all details to access precisely the sleeve-pile set interaction. The obtained results can establish practical conclusions to docking jacket analysis.

  20. Rational selection of training and test sets for the development of validated QSAR models

    NASA Astrophysics Data System (ADS)

    Golbraikh, Alexander; Shen, Min; Xiao, Zhiyan; Xiao, Yun-De; Lee, Kuo-Hsiung; Tropsha, Alexander

    2003-02-01

    Quantitative Structure-Activity Relationship (QSAR) models are used increasingly to screen chemical databases and/or virtual chemical libraries for potentially bioactive molecules. These developments emphasize the importance of rigorous model validation to ensure that the models have acceptable predictive power. Using k nearest neighbors ( kNN) variable selection QSAR method for the analysis of several datasets, we have demonstrated recently that the widely accepted leave-one-out (LOO) cross-validated R2 (q2) is an inadequate characteristic to assess the predictive ability of the models [Golbraikh, A., Tropsha, A. Beware of q2! J. Mol. Graphics Mod. 20, 269-276, (2002)]. Herein, we provide additional evidence that there exists no correlation between the values of q 2 for the training set and accuracy of prediction ( R 2) for the test set and argue that this observation is a general property of any QSAR model developed with LOO cross-validation. We suggest that external validation using rationally selected training and test sets provides a means to establish a reliable QSAR model. We propose several approaches to the division of experimental datasets into training and test sets and apply them in QSAR studies of 48 functionalized amino acid anticonvulsants and a series of 157 epipodophyllotoxin derivatives with antitumor activity. We formulate a set of general criteria for the evaluation of predictive power of QSAR models.

  1. Hyoid and laryngeal excursion kinematics - magnitude, duration and velocity - changes following successful exercise-based dysphagia rehabilitation: MDTP.

    PubMed

    Sia, I; Carvajal, P; Lacy, A A; Carnaby, G D; Crary, M A

    2015-05-01

    Variability in magnitude of deglutitional hyolaryngeal excursion in patients with dysphagia suggests that it does not adequately represent the kinematics of swallowing difficulties or recovery following rehabilitation. On the other hand, reduced hyolaryngeal excursion velocity has been reported in patients with dysphagia. While increased movement velocity often accompanies clinical and functional recovery in many diseases, velocity changes in swallowing-related movement following dysphagia therapy have not been well studied. This study evaluated changes in hyoid and laryngeal excursion (magnitude, duration and velocity) before and following successful dysphagia therapy to provide a more comprehensive representation of improvement to swallowing kinematics in patients who have experienced successful rehabilitation. A secondary analysis of case series data was completed. Eight patients with severe, chronic dysphagia completed a standard course of an exercise-based dysphagia treatment programme (McNeill dysphagia therapy program, MDTP). Pre- and post-treatment, kinematic aspects of swallowing were evaluated for thin liquid, thick liquid and pudding swallows. Maximum hyoid and laryngeal excursion magnitude and excursion duration were measured. Excursion velocities were calculated from excursion magnitude and duration measures. Successful treatment for dysphagia facilitated increased hyolaryngeal excursion magnitude, duration and velocity. These changes were most prominent for the hyoid and most often observed with thin liquids. By examining hyoid and laryngeal excursion velocity in patients who have experienced successful dysphagia rehabilitation, this study demonstrated the value of evaluating spatial and temporal aspects of swallowing kinematics in a single measure for a more comprehensive representation of positive changes underlying functional recovery.

  2. Robust non-rigid point set registration using student's-t mixture model.

    PubMed

    Zhou, Zhiyong; Zheng, Jian; Dai, Yakang; Zhou, Zhe; Chen, Shi

    2014-01-01

    The Student's-t mixture model, which is heavily tailed and more robust than the Gaussian mixture model, has recently received great attention on image processing. In this paper, we propose a robust non-rigid point set registration algorithm using the Student's-t mixture model. Specifically, first, we consider the alignment of two point sets as a probability density estimation problem and treat one point set as Student's-t mixture model centroids. Then, we fit the Student's-t mixture model centroids to the other point set which is treated as data. Finally, we get the closed-form solutions of registration parameters, leading to a computationally efficient registration algorithm. The proposed algorithm is especially effective for addressing the non-rigid point set registration problem when significant amounts of noise and outliers are present. Moreover, less registration parameters have to be set manually for our algorithm compared to the popular coherent points drift (CPD) algorithm. We have compared our algorithm with other state-of-the-art registration algorithms on both 2D and 3D data with noise and outliers, where our non-rigid registration algorithm showed accurate results and outperformed the other algorithms.

  3. A training set selection strategy for a universal near-infrared quantitative model.

    PubMed

    Jia, Yan-Hua; Liu, Xu-Ping; Feng, Yan-Chun; Hu, Chang-Qin

    2011-06-01

    The purpose of this article is to propose an empirical solution to the problem of how many clusters of complex samples should be selected to construct the training set for a universal near infrared quantitative model based on the Naes method. The sample spectra were hierarchically classified into clusters by Ward's algorithm and Euclidean distance. If the sample spectra were classified into two clusters, the 1/50 of the largest Heterogeneity value in the cluster with larger variation was set as the threshold to determine the total number of clusters. One sample was then randomly selected from each cluster to construct the training set, and the number of samples in training set equaled the number of clusters. In this study, 98 batches of rifampicin capsules with API contents ranging from 50.1% to 99.4% were studied with this strategy. The root mean square errors of cross validation and prediction were 2.54% and 2.31% for the model for rifampicin capsules, respectively. Then, we evaluated this model in terms of outlier diagnostics, accuracy, precision, and robustness. We also used the strategy of training set sample selection to revalidate the models for cefradine capsules, roxithromycin tablets, and erythromycin ethylsuccinate tablets, and the results were satisfactory. In conclusion, all results showed that this training set sample selection strategy assisted in the quick and accurate construction of quantitative models using near-infrared spectroscopy.

  4. Root cause analysis of overlay metrology excursions with scatterometry overlay technology (SCOL)

    NASA Astrophysics Data System (ADS)

    Gutjahr, Karsten; Park, Dongsuk; Zhou, Yue; Cho, Winston; Ahn, Ki Cheol; Snow, Patrick; McGowan, Richard; Marciano, Tal; Ramanathan, Vidya; Herrera, Pedro; Itzkovich, Tal; Camp, Janay; Adel, Michael

    2016-03-01

    We demonstrate a novel method to establish a root cause for an overlay excursion using optical Scatterometry metrology. Scatterometry overlay metrology consists of four cells (two per directions) of grating on grating structures that are illuminated with a laser and diffracted orders measured in the pupil plane within a certain range of aperture. State of art algorithms permit, with symmetric considerations over the targets, to extract the overlay between the two gratings. We exploit the optical properties of the target to extract further information from the measured pupil images, particularly information that maybe related to any change in the process that may lead to an overlay excursion. Root Cause Analysis or RCA is being developed to identify different kinds of process variations (either within the wafer, or between different wafers) that may indicate overlay excursions. In this manuscript, we demonstrate a collaboration between Globalfoundries and KLA-Tencor to identify a symmetric process variation using scatterometry overlay metrology and RCA technique.

  5. "Economic microscope": The agent-based model set as an instrument in an economic system research

    NASA Astrophysics Data System (ADS)

    Berg, D. B.; Zvereva, O. M.; Akenov, Serik

    2017-07-01

    To create a valid model of a social or economic system one must consider a lot of parameters, conditions and restrictions. Systems and, consequently, the corresponding models are proved to be very complicated. The problem of such system model engineering can't be solved only with mathematical methods usage. The decision could be found in computer simulation. Simulation does not reject mathematical methods, mathematical expressions could become the foundation for a computer model. In these materials the set of agent-based computer models is under discussion. All the set models simulate productive agents communications, but every model is geared towards the specific goal, and, thus, has its own algorithm and its own peculiarities. It is shown that computer simulation can discover new features of the agents' behavior that can not be obtained by analytical solvation of mathematical equations and thus plays the role of some kind of economic microscope.

  6. Determination of the Parameter Sets for the Best Performance of IPS-driven ENLIL Model

    NASA Astrophysics Data System (ADS)

    Yun, Jongyeon; Choi, Kyu-Cheol; Yi, Jonghyuk; Kim, Jaehun; Odstrcil, Dusan

    2016-12-01

    Interplanetary scintillation-driven (IPS-driven) ENLIL model was jointly developed by University of California, San Diego (UCSD) and National Aeronaucics and Space Administration/Goddard Space Flight Center (NASA/GSFC). The model has been in operation by Korean Space Weather Cetner (KSWC) since 2014. IPS-driven ENLIL model has a variety of ambient solar wind parameters and the results of the model depend on the combination of these parameters. We have conducted researches to determine the best combination of parameters to improve the performance of the IPS-driven ENLIL model. The model results with input of 1,440 combinations of parameters are compared with the Advanced Composition Explorer (ACE) observation data. In this way, the top 10 parameter sets showing best performance were determined. Finally, the characteristics of the parameter sets were analyzed and application of the results to IPS-driven ENLIL model was discussed.

  7. A comparison of simulation results from two terrestrial carbon cycle models using three climate data sets

    NASA Astrophysics Data System (ADS)

    Ito, Akihiko; Sasai, Takahiro

    2006-11-01

    This study addressed how different climate data sets influence simulations of the global terrestrial carbon cycle. For the period 1982-2001, we compared the results of simulations based on three climate data sets (NCEP/NCAR, NCEP/DOE AMIP-II and ERA40) employed in meteorological, ecological and biogeochemical studies and two different models (BEAMS and Sim-CYCLE). The models differed in their parameterizations of photosynthetic and phenological processes but used the same surface climate (e.g. shortwave radiation, temperature and precipitation), vegetation, soil and topography data. The three data sets give different climatic conditions, especially for shortwave radiation, in terms of long-term means, linear trends and interannual variability. Consequently, the simulation results for global net primary productivity varied by 16%-43% only from differences in the climate data sets, especially in these regions where the shortwave radiation data differed markedly: differences in the climate data set can strongly influence simulation results. The differences among the climate data set and between the two models resulted in slightly different spatial distribution and interannual variability in the net ecosystem carbon budget. To minimize uncertainty, we should pay attention to the specific climate data used. We recommend developing an accurate standard climate data set for simulation studies.

  8. Integrated SFM Techniques Using Data Set from Google Earth 3d Model and from Street Level

    NASA Astrophysics Data System (ADS)

    Inzerillo, L.

    2017-08-01

    Structure from motion (SfM) represents a widespread photogrammetric method that uses the photogrammetric rules to carry out a 3D model from a photo data set collection. Some complex ancient buildings, such as Cathedrals, or Theatres, or Castles, etc. need to implement the data set (realized from street level) with the UAV one in order to have the 3D roof reconstruction. Nevertheless, the use of UAV is strong limited from the government rules. In these last years, Google Earth (GE) has been enriched with the 3D models of the earth sites. For this reason, it seemed convenient to start to test the potentiality offered by GE in order to extract from it a data set that replace the UAV function, to close the aerial building data set, using screen images of high resolution 3D models. Users can take unlimited "aerial photos" of a scene while flying around in GE at any viewing angle and altitude. The challenge is to verify the metric reliability of the SfM model carried out with an integrated data set (the one from street level and the one from GE) aimed at replace the UAV use in urban contest. This model is called integrated GE SfM model (i-GESfM). In this paper will be present a case study: the Cathedral of Palermo.

  9. Evolving Non-Dominated Parameter Sets for Computational Models from Multiple Experiments

    NASA Astrophysics Data System (ADS)

    Lane, Peter C. R.; Gobet, Fernand

    2013-03-01

    Creating robust, reproducible and optimal computational models is a key challenge for theorists in many sciences. Psychology and cognitive science face particular challenges as large amounts of data are collected and many models are not amenable to analytical techniques for calculating parameter sets. Particular problems are to locate the full range of acceptable model parameters for a given dataset, and to confirm the consistency of model parameters across different datasets. Resolving these problems will provide a better understanding of the behaviour of computational models, and so support the development of general and robust models. In this article, we address these problems using evolutionary algorithms to develop parameters for computational models against multiple sets of experimental data; in particular, we propose the `speciated non-dominated sorting genetic algorithm' for evolving models in several theories. We discuss the problem of developing a model of categorisation using twenty-nine sets of data and models drawn from four different theories. We find that the evolutionary algorithms generate high quality models, adapted to provide a good fit to all available data.

  10. Dynamic changes in sulfate sulfur isotopes preceding the Ediacaran Shuram Excursion

    NASA Astrophysics Data System (ADS)

    Osburn, Magdalena R.; Owens, Jeremy; Bergmann, Kristin D.; Lyons, Timothy W.; Grotzinger, John P.

    2015-12-01

    Large excursions in δ13C and δ34S are found in sedimentary rocks from the Ediacaran Period that may provide detailed mechanistic information about oxidation of Earth's surface. However, poor stratigraphic resolution and diagenetic concerns have thus far limited the interpretation of these records. Here, we present a high-resolution record of carbon and sulfur isotopes from the Khufai Formation, leading up to and including the onset of the Shuram carbon isotope excursion. We document large coherent excursions in the sulfur isotope composition and concentration of carbonate-associated sulfate (CAS) that occur both independently and synchronously with the carbon isotope excursion. Isotopic changes appear decoupled from major stratigraphic surfaces and facies changes, suggesting regional or global processes rather than local controls. Our data suggest that very low marine sulfate concentrations are maintained at least through the middle-Khufai Formation and require that the burial fraction of pyrite and the fractionation factor between sulfate and pyrite necessarily change through deposition. Reconciliation of simultaneous, up-section increases in marine sulfate concentration and δ34SCAS requires the introduction of strongly 34S-enriched sulfate, possibly from weathering of Cryogenian and earlier Ediacaran 34S-enriched pyrite. Our analysis of the onset of the Shuram carbon isotope excursion, observed in stratigraphic and lithologic context, is not consistent with diagenetic or authigenic formation mechanisms. Instead, we observe a contemporaneous negative excursion in sulfate δ34S suggesting linked primary perturbations to the carbon and sulfur isotope systems. This work further constrains the size, isotopic composition, and potential input fluxes of the Ediacaran marine sulfate reservoir, placing mechanistic constraints on possible drivers of extreme isotopic perturbations during this critical period in Earth history.

  11. Reduced Diaphragm Excursion During Reflexive Citric Acid Cough Test in Subjects With Subacute Stroke.

    PubMed

    Choi, Yong-Min; Park, Geun-Young; Yoo, Yeonji; Sohn, Donggyun; Jang, YongJun; Im, Sun

    2017-09-12

    Diaphragm excursion is limited during respiratory maneuvers after a stroke. How the diaphragm is limited during reflexive coughs and affects the effectiveness of cough in stroke patients is unclear. This study aimed to measure reflexive cough strength by cough peak flow (CPF) induced by citric acid nebulization (2.8 mol/L), record diaphragm excursions during reflexive coughs in stroke subjects at risk of silent aspiration, and compare these values with those of stroke subjects without risk of aspiration or dysphagia. Twenty-one subjects with subacute stroke (mean stroke onset, 13.6 d) at risk of silent aspiration (penetration-aspiration scale, 8) and 21 stroke subjects without dysphagia or aspiration (controls) were included. Diaphragmatic excursions were assessed using real-time sonography in all subjects; the main outcome measure was reflexive CPF induced by citric acid nebulization. The median (interquartile range) values of citric acid-induced CPF values were significantly more reduced in the 21 subjects with silent aspiration (45 [0-83] L/min) than in the control subjects (97 [66-162] L/min) (P = .004). Diaphragmatic excursions during the reflexive coughs were also significantly reduced (P < .001), although both groups had a similar range in the initial National Institutes of Health Stroke Scale scores and level of disability, as measured by the modified Barthel index. Citric acid-induced CPF was significantly correlated with the number of generated coughs (rs = 0.69), voluntary cough CPF (rs = 0.85), and degree of diaphragm excursion on both sides (rs = 0.50 [hemiplegic] and rs = 0.55 [nonhemiplegic]) but not correlated with the degree of hemiparesis, National Institutes of Health Stroke Scale score, or modified Barthel index scores. The 6-month follow up revealed that 7 subjects in group A experienced aspiration pneumonia. Stroke subjects at risk of silent aspiration showed reduced CPF and more limited diaphragm excursion during the citric acid

  12. Head Excursion of Restrained Human Volunteers and Hybrid III Dummies in Steady State Rollover Tests

    PubMed Central

    Moffatt, Edward; Hare, Barry; Hughes, Raymond; Lewis, Lance; Iiyama, Hiroshi; Curzon, Anne; Cooper, Eddie

    2003-01-01

    Seatbelts provide substantial benefits in rollover crashes, yet occupants still receive head and neck injuries from contacting the vehicle roof interior when the roof exterior strikes the ground. Prior research has evaluated rollover restraint performance utilizing anthropomorphic test devices (dummies), but little dynamic testing has been done with human volunteers to learn how they move during rollovers. In this study, the vertical excursion of the head of restrained dummies and human subjects was measured in a vehicle being rotated about its longitudinal roll axis at roll rates from 180-to-360 deg/sec and under static inversion conditions. The vehicle’s restraint design was the commonly used 3-point seatbelt with continuous loop webbing and a sliding latch plate. This paper presents an analysis of the observed occupant motion and provides a comparison of dummy and human motion under similar test conditions. Thirty-five tests (eighteen static and seventeen dynamic) were completed using two different sizes of dummies and human subjects in both near and far-side roll directions. The research indicates that far-side rollovers cause the restrained test subjects to have greater head excursion than near-side rollovers, and that static inversion testing underestimates head excursion for far-side occupants. Human vertical head excursion of up to 200 mm was found at a roll rate of 220 deg/sec. Humans exhibit greater variability in head excursion in comparison to dummies. Transfer of seatbelt webbing through the latch plate did not correlate directly with differences in head excursion. PMID:12941241

  13. Improved Quaternary North Atlantic stratigraphy using relative paleointensity (RPI), oxygen isotopes, and magnetic excursions (Invited)

    NASA Astrophysics Data System (ADS)

    Channell, J. E.

    2013-12-01

    Improving the resolution of Quaternary marine stratigraphy is one of the major challenges in paleoceanography. IODP Expedition 303/306, and ODP Legs 162 and 172, have yielded multiple high-resolution records (mean sedimentation rates in the 7-20 cm/kyr range) of relative paleointensity (RPI) that are accompanied by oxygen isotope data and extend through much of the Quaternary. Tandem fit of RPI and oxygen isotope data to calibrated templates (LR04 and PISO), using the Match protocol, yields largely consistent stratigraphies, implying that both RPI and oxygen isotope data are dominated by regional/global signals. Based on the recent geomagnetic field, RPI can be expected to be a global signal (i.e. dominated by the axial dipole field) when recorded at sedimentation rates less than several decimeters/kyr. Magnetic susceptibility, on the other hand, is a local/regional lithologic signal, and therefore less useful for long-distance correlation. Magnetic excursions are directional phenomena and, when adequately recorded, are manifest as paired reversals in which the virtual geomagnetic poles (VGPs) reach high latitudes in the opposite hemisphere, and they occupy minima in RPI records. Reversed VGPs imply that excursions are attributable to the main axial dipole, and therefore provide global stratigraphy. The so-called Iceland Basin excursion is recorded at many IODP/ODP sites and lies at the MIS 6/7 boundary at ~188 ka, with a duration of 2-3 kyr. Other excursions in the Brunhes chron are less commonly recorded because their duration (perhaps <~1 kyr) requires sedimentation rates >20 cm/kyr to be adequately recorded. On the other hand, several excursions within the Matuyama Chron are more commonly recorded in North Atlantic drift sediments due to relatively elevated durations. With some notable exceptions (e.g. Iberian Margin), high quality RPI records from North Atlantic sediments, together with magnetic excursions, can be used in tandem with oxygen isotope data to

  14. The effects of climate downscaling technique and observational data set on modeled ecological responses

    Treesearch

    Afshin Pourmokhtarian; Charles T. Driscoll; John L. Campbell; Katharine Hayhoe; Anne M. K. Stoner

    2016-01-01

    Assessments of future climate change impacts on ecosystems typically rely on multiple climate model projections, but often utilize only one downscaling approach trained on one set of observations. Here, we explore the extent to which modeled biogeochemical responses to changing climate are affected by the selection of the climate downscaling method and training...

  15. Addressing HIV in the School Setting: Application of a School Change Model

    ERIC Educational Resources Information Center

    Walsh, Audra St. John; Chenneville, Tiffany

    2013-01-01

    This paper describes best practices for responding to youth with human immunodeficiency virus (HIV) in the school setting through the application of a school change model designed by the World Health Organization. This model applies a whole school approach and includes four levels that span the continuum from universal prevention to direct…

  16. Using an Agenda Setting Model to Help Students Develop & Exercise Participatory Skills and Values

    ERIC Educational Resources Information Center

    Perry, Anthony D.; Wilkenfeld, Britt S.

    2006-01-01

    The Agenda Setting Model is a program component that can be used in courses to contribute to students' development as responsible, effective, and informed citizens. This model involves students in finding a unified voice to assert an agenda of issues that they find especially pressing. This is often the only time students experience such a…

  17. Buttonpusher or Partner? Two Contrasting Models of Film Production in a University Setting.

    ERIC Educational Resources Information Center

    Pfaff, Gunter

    There are two distinct models of film production. One model, characterized as assembly line production, is the most prevalent in commercial settings and in universities. The project is initiated through management and progresses in an ordered flow of assembly through the hands of the specialized film workers; power is from the top down. The…

  18. Addressing HIV in the School Setting: Application of a School Change Model

    ERIC Educational Resources Information Center

    Walsh, Audra St. John; Chenneville, Tiffany

    2013-01-01

    This paper describes best practices for responding to youth with human immunodeficiency virus (HIV) in the school setting through the application of a school change model designed by the World Health Organization. This model applies a whole school approach and includes four levels that span the continuum from universal prevention to direct…

  19. Using an Agenda Setting Model to Help Students Develop & Exercise Participatory Skills and Values

    ERIC Educational Resources Information Center

    Perry, Anthony D.; Wilkenfeld, Britt S.

    2006-01-01

    The Agenda Setting Model is a program component that can be used in courses to contribute to students' development as responsible, effective, and informed citizens. This model involves students in finding a unified voice to assert an agenda of issues that they find especially pressing. This is often the only time students experience such a…

  20. Information Content in Data Sets for a Nucleated-Polymerization Model

    PubMed Central

    Banks, H.T.; Doumic, Marie; Kruse, Carola; Prigent, Stephanie; Rezaei, Human

    2015-01-01

    We illustrate the use of statistical tools (asymptotic theories of standard error quantification using appropriate statistical models, bootstrapping, model comparison techniques) in addition to sensitivity analysis that may be employed to determine the information content in data sets. We do this in the context of recent models [25] for nucleated polymerization in proteins, about which very little is known regarding the underlying mechanisms; thus the methodology we develop here may be of great help to experimentalists. We conclude that the investigated data sets will support with reasonable levels of uncertainty only the estimation of the parameters related to the early steps of the aggregation process. PMID:26046598

  1. On some questions in computer modeling of the reachability sets constructing problems

    NASA Astrophysics Data System (ADS)

    Ushakov, V. N.; Parshikov, G. V.; Matviychuk, A. R.

    2016-10-01

    The research considers the problem of constructing the reachability sets of non-linear dynamical system in n-dimensional Euclidean space on the fixed time interval. The approximate solution methods of the reachability sets constructing are considered in this research as well as the accuracy estimation for this methods is given. The research contains the computational experiments on computer modeling of described reachability sets constructing methods, which use the algorithms implemented for two computation technologies CPU as well as GPU (using CUDA technology). In this research the description and comparison of approaches to the computer modeling of the problem are given. Furthermore, the CPU-based computer modeling result comparison with the result obtained on GPU based on CUDA technology are presented. Besides, this research discusses some the side issues appeared during computer modeling, the issues raised during the computer algorithms implementation, as well as the ways to eliminate these issues or reduce their impact.

  2. Consistency of QSAR models: Correct split of training and test sets, ranking of models and performance parameters.

    PubMed

    Rácz, A; Bajusz, D; Héberger, K

    2015-01-01

    Recent implementations of QSAR modelling software provide the user with numerous models and a wealth of information. In this work, we provide some guidance on how one should interpret the results of QSAR modelling, compare and assess the resulting models, and select the best and most consistent ones. Two QSAR datasets are applied as case studies for the comparison of model performance parameters and model selection methods. We demonstrate the capabilities of sum of ranking differences (SRD) in model selection and ranking, and identify the best performance indicators and models. While the exchange of the original training and (external) test sets does not affect the ranking of performance parameters, it provides improved models in certain cases (despite the lower number of molecules in the training set). Performance parameters for external validation are substantially separated from the other merits in SRD analyses, highlighting their value in data fusion.

  3. Secondary Structure Predictions for Long RNA Sequences Based on Inversion Excursions and MapReduce.

    PubMed

    Yehdego, Daniel T; Zhang, Boyu; Kodimala, Vikram K R; Johnson, Kyle L; Taufer, Michela; Leung, Ming-Ying

    2013-05-01

    Secondary structures of ribonucleic acid (RNA) molecules play important roles in many biological processes including gene expression and regulation. Experimental observations and computing limitations suggest that we can approach the secondary structure prediction problem for long RNA sequences by segmenting them into shorter chunks, predicting the secondary structures of each chunk individually using existing prediction programs, and then assembling the results to give the structure of the original sequence. The selection of cutting points is a crucial component of the segmenting step. Noting that stem-loops and pseudoknots always contain an inversion, i.e., a stretch of nucleotides followed closely by its inverse complementary sequence, we developed two cutting methods for segmenting long RNA sequences based on inversion excursions: the centered and optimized method. Each step of searching for inversions, chunking, and predictions can be performed in parallel. In this paper we use a MapReduce framework, i.e., Hadoop, to extensively explore meaningful inversion stem lengths and gap sizes for the segmentation and identify correlations between chunking methods and prediction accuracy. We show that for a set of long RNA sequences in the RFAM database, whose secondary structures are known to contain pseudoknots, our approach predicts secondary structures more accurately than methods that do not segment the sequence, when the latter predictions are possible computationally. We also show that, as sequences exceed certain lengths, some programs cannot computationally predict pseudoknots while our chunking methods can. Overall, our predicted structures still retain the accuracy level of the original prediction programs when compared with known experimental secondary structure.

  4. Symmetry-enriched string nets: Exactly solvable models for SET phases

    NASA Astrophysics Data System (ADS)

    Heinrich, Chris; Burnell, Fiona; Fidkowski, Lukasz; Levin, Michael

    2016-12-01

    We construct exactly solvable models for a wide class of symmetry-enriched topological (SET) phases. Our construction applies to two-dimensional (2D) bosonic SET phases with finite unitary on-site symmetry group G and we conjecture that our models realize every phase in this class that can be described by a commuting projector Hamiltonian. Our models are designed so that they have a special property: If we couple them to a dynamical lattice gauge field with gauge group G , the resulting gauge theories are equivalent to string-net models. This property is what allows us to analyze our models in generality. As an example, we present a model for a phase with the same anyon excitations as the toric code and with a Z2 symmetry which exchanges the e and m type anyons. We further illustrate our construction with a number of additional examples.

  5. A Dual Hesitant Fuzzy Multigranulation Rough Set over Two-Universe Model for Medical Diagnoses

    PubMed Central

    Zhang, Chao; Li, Deyu; Yan, Yan

    2015-01-01

    In medical science, disease diagnosis is one of the difficult tasks for medical experts who are confronted with challenges in dealing with a lot of uncertain medical information. And different medical experts might express their own thought about the medical knowledge base which slightly differs from other medical experts. Thus, to solve the problems of uncertain data analysis and group decision making in disease diagnoses, we propose a new rough set model called dual hesitant fuzzy multigranulation rough set over two universes by combining the dual hesitant fuzzy set and multigranulation rough set theories. In the framework of our study, both the definition and some basic properties of the proposed model are presented. Finally, we give a general approach which is applied to a decision making problem in disease diagnoses, and the effectiveness of the approach is demonstrated by a numerical example. PMID:26858772

  6. The value of multiple data set calibration versus model complexity for improving the performance of hydrological models in mountain catchments

    NASA Astrophysics Data System (ADS)

    Finger, David; Vis, Marc; Huss, Matthias; Seibert, Jan

    2015-04-01

    The assessment of snow, glacier, and rainfall runoff contribution to discharge in mountain streams is of major importance for an adequate water resource management. Such contributions can be estimated via hydrological models, provided that the modeling adequately accounts for snow and glacier melt, as well as rainfall runoff. We present a multiple data set calibration approach to estimate runoff composition using hydrological models with three levels of complexity. For this purpose, the code of the conceptual runoff model HBV-light was enhanced to allow calibration and validation of simulations against glacier mass balances, satellite-derived snow cover area and measured discharge. Three levels of complexity of the model were applied to glacierized catchments in Switzerland, ranging from 39 to 103 km2. The results indicate that all three observational data sets are reproduced adequately by the model, allowing an accurate estimation of the runoff composition in the three mountain streams. However, calibration against only runoff leads to unrealistic snow and glacier melt rates. Based on these results, we recommend using all three observational data sets in order to constrain model parameters and compute snow, glacier, and rain contributions. Finally, based on the comparison of model performance of different complexities, we postulate that the availability and use of different data sets to calibrate hydrological models might be more important than model complexity to achieve realistic estimations of runoff composition.

  7. Heat transfer in fish: are short excursions between habitats a thermoregulatory behaviour to exploit resources in an unfavourable thermal environment?

    PubMed

    Pépino, Marc; Goyer, Katerine; Magnan, Pierre

    2015-11-01

    Temperature is the primary environmental factor affecting physiological processes in ectotherms. Heat-transfer models describe how the fish's internal temperature responds to a fluctuating thermal environment. Specifically, the rate coefficient (k), defined as the instantaneous rate of change in body temperature in relation to the difference between ambient and body temperature, summarizes the combined effects of direct thermal conduction through body mass, passive convection (intracellular and intercellular fluids) and forced convective heat transfer (cardiovascular system). The k-coefficient is widely used in fish ecology to understand how body temperature responds to changes in water temperature. The main objective of this study was to estimate the k-coefficient of brook charr equipped with internal temperature-sensitive transmitters in controlled laboratory experiments. Fish were first transferred from acclimation tanks (10°C) to tanks at 14, 19 or 23°C (warming experiments) and were then returned to the acclimation tanks (10°C; cooling experiments), thus producing six step changes in ambient temperature. We used non-linear mixed models to estimate the k-coefficient. Model comparisons indicated that the model incorporating the k-coefficient as a function of absolute temperature difference (dT: 4, 9 and 13°C) best described body temperature change. By simulating body temperature in a heterogeneous thermal environment, we provide theoretical predictions of maximum excursion duration between feeding and resting areas. Our simulations suggest that short (i.e. <60 min) excursions could be a common thermoregulatory behaviour adopted by cold freshwater fish species to sustain body temperature below a critical temperature threshold, enabling them to exploit resources in an unfavourable thermal environment. © 2015. Published by The Company of Biologists Ltd.

  8. Modeling the three-dimensional structure of RNA using discrete nucleotide conformational sets.

    PubMed

    Gautheret, D; Major, F; Cedergren, R

    1993-02-20

    The flexibility about seven torsion angles in nucleotides constitutes a severe obstacle to computer modeling of RNA. The computational feasibility of RNA conformational searches can be enhanced by assigning to each nucleotide a set of discrete conformations. In this work, four types of discrete conformational sets for the atomic representation of nucleotide structures were defined and evaluated. These sets, comprising between 10 and 30 conformations, were tested for their ability to reproduce known RNA structures and to generate structures responding to new specifications. Conformational searches were performed with the MC-SYM program, which allows for the generation of all structures satisfying a predetermined set of three-dimensional constraints in a given discrete space. Results with known hairpin loop structures show that root-mean-square deviations of about 1.5 A for backbone atoms and about 2.0 A for all atoms between the modeled and X-ray crystal structures can be expected. The conformational set that gives the most faithful representation of test structures is based on the classification of nucleotide conformations derived from a structural database. Representative conformations are selected from each class that adequately sample variations in backbone direction, sugar pucker and base orientation. With this conformational set, most of the important features of test hairpin structures are reproduced with fidelity, indicating that biologically useful models can be constructed from the combination of discrete nucleotide conformations and an algorithm that rapidly and systematically scans the pre-defined conformational space.

  9. THE DEVELOPMENT AND USE OF A MODEL TO PREDICT SUSTAINABILITY OF CHANGE IN HEALTH CARE SETTINGS

    PubMed Central

    Molfenter, Todd; Ford, James H; Bhattacharya, Abhik

    2011-01-01

    Innovations adopted through organizational change initiatives are often not sustained leading to diminished quality, productivity, and consumer satisfaction. Research explaining variance in the use of adopted innovations in health care settings is sparse, suggesting the need for a theoretical model to guide research and practice. In this article, we describe the development of a hybrid conjoint decision theoretic model designed to predict the sustainability of organizational change in health care settings. An initial test of the model’s predictive validity using expert scored hypothetic profiles resulted in an r-squared value of .77. The test of this model offers a theoretical base for future research on the sustainability of change in health care settings. PMID:22262947

  10. Multiple Versus Single Set Validation of Multivariate Models to Avoid Mistakes.

    PubMed

    Harrington, Peter de Boves

    2017-08-04

    Validation of multivariate models is of current importance for a wide range of chemical applications. Although important, it is neglected. The common practice is to use a single external validation set for evaluation. This approach is deficient and may mislead investigators with results that are specific to the single validation set of data. In addition, no statistics are available regarding the precision of a derived figure of merit (FOM). A statistical approach using bootstrapped Latin partitions is advocated. This validation method makes efficient use of the data because each object is used once for validation. It was reviewed a decade earlier but primarily for optimization of chemometric models (1) , this review presents the reasons it should be used for generalized statistical validation. Average FOMs with confidence intervals are reported and powerful, matched-sample statistics may be applied for comparing models and methods. Examples demonstrate the problems with single validation sets.

  11. Neural model for learning-to-learn of novel task sets in the motor domain.

    PubMed

    Pitti, Alexandre; Braud, Raphaël; Mahé, Sylvain; Quoy, Mathias; Gaussier, Philippe

    2013-01-01

    During development, infants learn to differentiate their motor behaviors relative to various contexts by exploring and identifying the correct structures of causes and effects that they can perform; these structures of actions are called task sets or internal models. The ability to detect the structure of new actions, to learn them and to select on the fly the proper one given the current task set is one great leap in infants cognition. This behavior is an important component of the child's ability of learning-to-learn, a mechanism akin to the one of intrinsic motivation that is argued to drive cognitive development. Accordingly, we propose to model a dual system based on (1) the learning of new task sets and on (2) their evaluation relative to their uncertainty and prediction error. The architecture is designed as a two-level-based neural system for context-dependent behavior (the first system) and task exploration and exploitation (the second system). In our model, the task sets are learned separately by reinforcement learning in the first network after their evaluation and selection in the second one. We perform two different experimental setups to show the sensorimotor mapping and switching between tasks, a first one in a neural simulation for modeling cognitive tasks and a second one with an arm-robot for motor task learning and switching. We show that the interplay of several intrinsic mechanisms drive the rapid formation of the neural populations with respect to novel task sets.

  12. Accurate Predictions of Mean Geomagnetic Dipole Excursion and Reversal Frequencies, Mean Paleomagnetic Field Intensity, and the Radius of Earth's Core Using McLeod's Rule

    NASA Technical Reports Server (NTRS)

    Voorhies, Coerte V.; Conrad, Joy

    1996-01-01

    The geomagnetic spatial power spectrum R(sub n)(r) is the mean square magnetic induction represented by degree n spherical harmonic coefficients of the internal scalar potential averaged over the geocentric sphere of radius r. McLeod's Rule for the magnetic field generated by Earth's core geodynamo says that the expected core surface power spectrum (R(sub nc)(c)) is inversely proportional to (2n + 1) for 1 less than n less than or equal to N(sub E). McLeod's Rule is verified by locating Earth's core with main field models of Magsat data; the estimated core radius of 3485 kn is close to the seismologic value for c of 3480 km. McLeod's Rule and similar forms are then calibrated with the model values of R(sub n) for 3 less than or = n less than or = 12. Extrapolation to the degree 1 dipole predicts the expectation value of Earth's dipole moment to be about 5.89 x 10(exp 22) Am(exp 2)rms (74.5% of the 1980 value) and the expected geomagnetic intensity to be about 35.6 (mu)T rms at Earth's surface. Archeo- and paleomagnetic field intensity data show these and related predictions to be reasonably accurate. The probability distribution chi(exp 2) with 2n+1 degrees of freedom is assigned to (2n + 1)R(sub nc)/(R(sub nc). Extending this to the dipole implies that an exceptionally weak absolute dipole moment (less than or = 20% of the 1980 value) will exist during 2.5% of geologic time. The mean duration for such major geomagnetic dipole power excursions, one quarter of which feature durable axial dipole reversal, is estimated from the modern dipole power time-scale and the statistical model of excursions. The resulting mean excursion duration of 2767 years forces us to predict an average of 9.04 excursions per million years, 2.26 axial dipole reversals per million years, and a mean reversal duration of 5533 years. Paleomagnetic data show these predictions to be quite accurate. McLeod's Rule led to accurate predictions of Earth's core radius, mean paleomagnetic field

  13. Proposed SPAR Modeling Method for Quantifying Time Dependent Station Blackout Cut Sets

    SciTech Connect

    John A. Schroeder

    2010-06-01

    Abstract: The U.S. Nuclear Regulatory Commission’s (USNRC’s) Standardized Plant Analysis Risk (SPAR) models and industry risk models take similar approaches to analyzing the risk associated with loss of offsite power and station blackout (LOOP/SBO) events at nuclear reactor plants. In both SPAR models and industry models, core damage risk resulting from a LOOP/SBO event is analyzed using a combination of event trees and fault trees that produce cut sets that are, in turn, quantified to obtain a numerical estimate of the resulting core damage risk. A proposed SPAR method for quantifying the time-dependent cut sets is sometimes referred to as a convolution method. The SPAR method reflects assumptions about the timing of emergency diesel failures, the timing of subsequent attempts at emergency diesel repair, and the timing of core damage that may be different than those often used in industry models. This paper describes the proposed SPAR method.

  14. Elephants, Whales, and Dinosaurs: An Excursion into Biomechanics.

    ERIC Educational Resources Information Center

    McGuire, Thomas

    1987-01-01

    Describes an activity designed to help children understand why there is a limit to the size of animals that live on land. Details the materials and set-up for this activity. Contains a reproducible, three-part activity sheet to accompany the activity. A key for the teacher is included. (CW)

  15. Influence of turbulence model parameter settings on conjugate heat transfer simulation

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Li, Yu; Zou, Zhengping; Wang, Lei; Song, Songhe

    2014-04-01

    Rationality of the parameter settings in turbulence model is an important factor affecting the accuracy of conjugate heat transfer (CHT) prediction. On the basis of a developed CHT methodology and the experimental data of Mark// cooling turbine blade, influences of the turbulence model parameter settings and the selection of turbulence models on CHT simulation are investigated. Results and comparisons with experimental data indicate that the inlet setting of the in Spalart-Allmaras model has nearly no influence on flow and heat transfer in blade surface. The inlet turbulence length scale l T in the low-Reynolds number Chien k- ɛ turbulence model and the blade surface roughness in shear stress transport (SST) k- ω SST model have relatively obvious effects on the blade surface temperature which increases with the increase of them. Both of the laminar Prandtl number and turbulent Prandtl number have slight influences on the prediction, and they only need to be constant in CHT simulation. The k- ω SST model has the best accuracy in the turbine blade CHT simulation compared with the other two models.

  16. Use of an Anatomical Scalar to Control for Sex-Based Size Differences in Measures of Hyoid Excursion during Swallowing

    ERIC Educational Resources Information Center

    Molfenter, Sonja M.; Steele, Catriona M.

    2014-01-01

    Purpose: Traditional methods for measuring hyoid excursion from dynamic videofluoroscopy recordings involve calculating changes in position in absolute units (mm). This method shows a high degree of variability across studies but agreement that greater hyoid excursion occurs inmen than in women. Given that men are typically taller than women, the…

  17. Use of an Anatomical Scalar to Control for Sex-Based Size Differences in Measures of Hyoid Excursion during Swallowing

    ERIC Educational Resources Information Center

    Molfenter, Sonja M.; Steele, Catriona M.

    2014-01-01

    Purpose: Traditional methods for measuring hyoid excursion from dynamic videofluoroscopy recordings involve calculating changes in position in absolute units (mm). This method shows a high degree of variability across studies but agreement that greater hyoid excursion occurs inmen than in women. Given that men are typically taller than women, the…

  18. Using Bayesian Multilevel Whole Genome Regression Models for Partial Pooling of Training Sets in Genomic Prediction

    PubMed Central

    Technow, Frank; Totir, L. Radu

    2015-01-01

    Training set size is an important determinant of genomic prediction accuracy. Plant breeding programs are characterized by a high degree of structuring, particularly into populations. This hampers the establishment of large training sets for each population. Pooling populations increases training set size but ignores unique genetic characteristics of each. A possible solution is partial pooling with multilevel models, which allows estimating population-specific marker effects while still leveraging information across populations. We developed a Bayesian multilevel whole-genome regression model and compared its performance with that of the popular BayesA model applied to each population separately (no pooling) and to the joined data set (complete pooling). As an example, we analyzed a wide array of traits from the nested association mapping maize population. There we show that for small population sizes (e.g., <50), partial pooling increased prediction accuracy over no or complete pooling for populations represented in the training set. No pooling was superior; however, when populations were large. In another example data set of interconnected biparental maize populations either partial or complete pooling was superior, depending on the trait. A simulation showed that no pooling is superior when differences in genetic effects among populations are large and partial pooling when they are intermediate. With small differences, partial and complete pooling achieved equally high accuracy. For prediction of new populations, partial and complete pooling had very similar accuracy in all cases. We conclude that partial pooling with multilevel models can maximize the potential of pooling by making optimal use of information in pooled training sets. PMID:26024866

  19. Predicting inpatient clinical order patterns with probabilistic topic models vs conventional order sets.

    PubMed

    Chen, Jonathan H; Goldstein, Mary K; Asch, Steven M; Mackey, Lester; Altman, Russ B

    2017-05-01

    Build probabilistic topic model representations of hospital admissions processes and compare the ability of such models to predict clinical order patterns as compared to preconstructed order sets. The authors evaluated the first 24 hours of structured electronic health record data for > 10 K inpatients. Drawing an analogy between structured items (e.g., clinical orders) to words in a text document, the authors performed latent Dirichlet allocation probabilistic topic modeling. These topic models use initial clinical information to predict clinical orders for a separate validation set of > 4 K patients. The authors evaluated these topic model-based predictions vs existing human-authored order sets by area under the receiver operating characteristic curve, precision, and recall for subsequent clinical orders. Existing order sets predict clinical orders used within 24 hours with area under the receiver operating characteristic curve 0.81, precision 16%, and recall 35%. This can be improved to 0.90, 24%, and 47% ( P  < 10 -20 ) by using probabilistic topic models to summarize clinical data into up to 32 topics. Many of these latent topics yield natural clinical interpretations (e.g., "critical care," "pneumonia," "neurologic evaluation"). Existing order sets tend to provide nonspecific, process-oriented aid, with usability limitations impairing more precise, patient-focused support. Algorithmic summarization has the potential to breach this usability barrier by automatically inferring patient context, but with potential tradeoffs in interpretability. Probabilistic topic modeling provides an automated approach to detect thematic trends in patient care and generate decision support content. A potential use case finds related clinical orders for decision support.

  20. Predicting inpatient clinical order patterns with probabilistic topic models vs conventional order sets

    PubMed Central

    Goldstein, Mary K; Asch, Steven M; Mackey, Lester; Altman, Russ B

    2017-01-01

    Objective: Build probabilistic topic model representations of hospital admissions processes and compare the ability of such models to predict clinical order patterns as compared to preconstructed order sets. Materials and Methods: The authors evaluated the first 24 hours of structured electronic health record data for > 10 K inpatients. Drawing an analogy between structured items (e.g., clinical orders) to words in a text document, the authors performed latent Dirichlet allocation probabilistic topic modeling. These topic models use initial clinical information to predict clinical orders for a separate validation set of > 4 K patients. The authors evaluated these topic model-based predictions vs existing human-authored order sets by area under the receiver operating characteristic curve, precision, and recall for subsequent clinical orders. Results: Existing order sets predict clinical orders used within 24 hours with area under the receiver operating characteristic curve 0.81, precision 16%, and recall 35%. This can be improved to 0.90, 24%, and 47% (P < 10−20) by using probabilistic topic models to summarize clinical data into up to 32 topics. Many of these latent topics yield natural clinical interpretations (e.g., “critical care,” “pneumonia,” “neurologic evaluation”). Discussion: Existing order sets tend to provide nonspecific, process-oriented aid, with usability limitations impairing more precise, patient-focused support. Algorithmic summarization has the potential to breach this usability barrier by automatically inferring patient context, but with potential tradeoffs in interpretability. Conclusion: Probabilistic topic modeling provides an automated approach to detect thematic trends in patient care and generate decision support content. A potential use case finds related clinical orders for decision support. PMID:27655861

  1. An analytical solution set for a four-compartment mixed mammillary/catenary model.

    PubMed

    Charkes, N D; Siegel, J A

    1999-06-01

    The purpose of this study was to extract the intercompartmental rate constants analytically from the coefficients and exponents of the exponential sum fitted to tracer data points for a unique four-compartment mixed mammillary/catenary (extended mammillary, radial) model, with losses solely from the central (blood) compartment. This model is useful in estimating myocardial and skeletal blood flow. Using Laplace transforms, the transfer functions of the exponential sum and the differential equations describing the model were obtained and the corresponding coefficients equated sequentially, which yielded the intercompartmental rate constants. Three solution sets of rate constants were found for the model, each of which satisfies both transfer functions. A program written in BASIC is provided, which requires only the coefficients and exponents of the exponential terms as input; the output is the three sets of rate constants. An example is given as an aid in debugging. Only one solution set of the three was physiologically realizable in the example, but the bounds defining these limits are not known. The advantages and limitations of the method are discussed. The method is suitable for initializing a non-linear least-squares fitting program for the rate constants. The appropriate physiological solution set for this model yields fractional and total myocardial or skeletal blood flow in a subject in the steady state.

  2. Multicultural Group Work on Field Excursions to Promote Student Teachers' Intercultural Competence

    ERIC Educational Resources Information Center

    Brendel, Nina; Aksit, Fisun; Aksit, Selahattin; Schrüfer, Gabriele

    2016-01-01

    As a response to the intercultural challenges of Geography Education, this study seeks to determine factors fostering intercultural competence of student teachers. Based on a one-week multicultural field excursion of eight German and eight Turkish students in Kayseri (Turkey) on Education for Sustainable Development, we used qualitative interviews…

  3. Scaphoid tuberosity excursion is minimized during a dart-throwing motion: A biomechanical study.

    PubMed

    Werner, Frederick W; Sutton, Levi G; Basu, Niladri; Short, Walter H; Moritomo, Hisao; St-Amand, Hugo

    2016-01-01

    The purpose of this study was to determine whether the excursion of the scaphoid tuberosity and therefore scaphoid motion is minimized during a dart-throwing motion. Scaphoid tuberosity excursion was studied as an indicator of scaphoid motion in 29 cadaver wrists as they were moved through wrist flexion-extension, radioulnar deviation, and a dart-throwing motion. Study results demonstrate that excursion was significantly less during the dart-throwing motion than during either wrist flexion-extension or radioulnar deviation. If the goal of early wrist motion after carpal ligament or distal radius injury and reconstruction is to minimize loading of the healing structures, a wrist motion in which scaphoid motion is minimal should reduce length changes in associated ligamentous structures. Therefore, during rehabilitation, if a patient uses a dart-throwing motion that minimizes his or her scaphoid tuberosity excursion, there should be minimal changes in ligament loading while still allowing wrist motion. Bench research, biomechanics, and cross-sectional. Not applicable. The study was laboratory based. Copyright © 2016 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.

  4. The Carnian (Late Triassic) carbon isotope excursion: new insights from the terrestrial realm

    NASA Astrophysics Data System (ADS)

    Miller, Charlotte; Kürschner, Wolfram; Peterse, Francien; Baranyi, Viktoria; Reichart, Gert-Jan

    2016-04-01

    The geological record contains evidence for numerous pronounced perturbations in the global carbon cycle, some of which are associated with eruptions from large igneous provinces (LIP), and consequently, ocean acidification and mass extinction. In the Carnian (Late Triassic), evidence from sedimentology and fossil pollen points to a significant change in climate, resulting in biotic turnover: during a period termed the 'Carnian Pluvial Event' (CPE). Additionally, during the Carnian, large volumes of flood basalts were erupted from the Wrangellia LIP (western North America). Evidence from the marine realm suggests a fundamental relationship between the CPE, a global 'wet' period, and the injection of light carbon into the atmosphere from the LIP. Here we provide the first evidence from the terrestrial realm of a significant negative δ13C excursion through the CPE recorded in the sedimentary archive of the Wiscombe Park Borehole, Devon (UK). Both total organic matter and plant leaf waxes reflect a gradual carbon isotope excursion of ~-5‰ during this time interval. Our data provides evidence for the global nature of this isotope excursion, supporting the hypothesis that the excursion was likely the result of an injection of light carbon into the atmosphere from the Wrangellia LIP.

  5. IDEA: A Language Learning Excursion: Making Communication Central in the Community College Classroom.

    ERIC Educational Resources Information Center

    Johnson, David

    1996-01-01

    Notes that one way to ensure that students understand the importance of developing communicative abilities is to utilize Spanish language resources in the United States, as in an excursion to a "tienda" (shop), where they negotiate with the Spanish-speaking owner. (seven references) (Author/CK)

  6. On the excursions of drifted Brownian motion and the successive passage times of Brownian motion

    NASA Astrophysics Data System (ADS)

    Abundo, Mario

    2016-09-01

    By using the law of the excursions of Brownian motion with drift, we find the distribution of the nth passage time of Brownian motion through a straight line S(t) = a + bt. In the special case when b = 0, we extend the result to a space-time transformation of Brownian motion.

  7. Multicultural Group Work on Field Excursions to Promote Student Teachers' Intercultural Competence

    ERIC Educational Resources Information Center

    Brendel, Nina; Aksit, Fisun; Aksit, Selahattin; Schrüfer, Gabriele

    2016-01-01

    As a response to the intercultural challenges of Geography Education, this study seeks to determine factors fostering intercultural competence of student teachers. Based on a one-week multicultural field excursion of eight German and eight Turkish students in Kayseri (Turkey) on Education for Sustainable Development, we used qualitative interviews…

  8. Development of optimization models for the set behavior and compressive strength of sodium activated geopolymer pastes

    NASA Astrophysics Data System (ADS)

    Fillenwarth, Brian Albert

    As large countries such as China begin to industrialize and concerns about global warming continue to grow, there is an increasing need for more environmentally friendly building materials. One promising material known as a geopolymer can be used as a portland cement replacement and in this capacity emits around 67% less carbon dioxide. In addition to potentially reducing carbon emissions, geopolymers can be synthesized with many industrial waste products such as fly ash. Although the benefits of geopolymers are substantial, there are a few difficulties with designing geopolymer mixes which have hindered widespread commercialization of the material. One such difficulty is the high variability of the materials used for their synthesis. In addition to this, interrelationships between mix design variables and how these interrelationships impact the set behavior and compressive strength are not well understood. A third complicating factor with designing geopolymer mixes is that the role of calcium in these systems is not well understood. In order to overcome these barriers, this study developed predictive optimization models through the use of genetic programming with experimentally collected set times and compressive strengths of several geopolymer paste mixes. The developed set behavior models were shown to predict the correct set behavior from the mix design over 85% of the time. The strength optimization model was shown to be capable of predicting compressive strengths of geopolymer pastes from their mix design to within about 1 ksi of their actual strength. In addition to this the optimization models give valuable insight into the key factors influencing strength development as well as the key factors responsible for flash set and long set behaviors in geopolymer pastes. A method for designing geopolymer paste mixes was developed from the generated optimization models. This design method provides an invaluable tool for use in future geopolymer research as well as

  9. A model providing long-term data sets of energetic electron precipitation during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Kamp, M.; Seppälä, A.; Clilverd, M. A.; Rodger, C. J.; Verronen, P. T.; Whittaker, I. C.

    2016-10-01

    The influence of solar variability on the polar atmosphere and climate due to energetic electron precipitation (EEP) has remained an open question largely due to lack of a long-term EEP forcing data set that could be used in chemistry-climate models. Motivated by this, we have developed a model for 30-1000 keV radiation belt driven EEP. The model is based on precipitation data from low Earth orbiting POES satellites in the period 2002-2012 and empirically described plasmasphere structure, which are both scaled to a geomagnetic index. This geomagnetic index is the only input of the model and can be either Dst or Ap. Because of this, the model can be used to calculate the energy-flux spectrum of precipitating electrons from 1957 (Dst) or 1932 (Ap) onward, with a time resolution of 1 day. Results from the model compare well with EEP observations over the period of 2002-2012. Using the model avoids the challenges found in measured data sets concerning proton contamination. As demonstrated, the model results can be used to produce the first ever >80 year long atmospheric ionization rate data set for radiation belt EEP. The impact of precipitation in this energy range is mainly seen at altitudes 70-110 km. The ionization rate data set, which is available for the scientific community, will enable simulations of EEP impacts on the atmosphere and climate with realistic EEP variability. Due to limitations in this first version of the model, the results most likely represent an underestimation of the total EEP effect.

  10. Engaging students in research learning experiences through hydrology field excursions and short films

    NASA Astrophysics Data System (ADS)

    Ewen, Tracy; Seibert, Jan

    2015-04-01

    One of the best ways to engage students and instill enthusiasm for hydrology is to expose them to hands-on learning. A focus on hydrology field research can be used to develop context-rich and active learning, and help solidify idealized learning where students are introduced to individual processes through textbook examples, often neglecting process interactions and an appreciation for the complexity of the system. We introduced a field course where hydrological measurement techniques are used to study processes such as snow hydrology and runoff generation, while also introducing students to field research and design of their own field project. Additionally, we produced short films of each of these research-based field excursions, with in-house film expertise. These films present a short overview of field methods applied in alpine regions and will be used for our larger introductory hydrology courses, exposing students to field research at an early stage, and for outreach activities, including for potential high school students curious about hydrology. In the field course, students design a low-budget experiment with the aim of going through the different steps of a 'real' scientific project, from formulating the research question to presenting their results. During the field excursions, students make discharge measurements in several alpine streams with a salt tracer to better understand the spatial characteristics of an alpine catchment, where source waters originate and how they contribute to runoff generation. Soil moisture measurements taken by students in this field excursion were used to analyze spatial soil moisture patterns in the alpine catchment and subsequently used in a publication. Another field excursion repeats a published experiment, where preferential soil flow paths are studied using a tracer and compared to previously collected data. For each field excursion, observational data collected by the students is uploaded to an online database we

  11. Four competing interactions for models with an uncountable set of spin values on a Cayley tree

    NASA Astrophysics Data System (ADS)

    Rozikov, U. A.; Haydarov, F. H.

    2017-06-01

    We consider models with four competing interactions ( external field, nearest neighbor, second neighbor, and three neighbors) and an uncountable set [0, 1] of spin values on the Cayley tree of order two. We reduce the problem of describing the splitting Gibbs measures of the model to the problem of analyzing solutions of a nonlinear integral equation and study some particular cases for Ising and Potts models. We also show that periodic Gibbs measures for the given models either are translation invariant or have the period two. We present examples where periodic Gibbs measures with the period two are not unique.

  12. CUTSETS - MINIMAL CUT SET CALCULATION FOR DIGRAPH AND FAULT TREE RELIABILITY MODELS

    NASA Technical Reports Server (NTRS)

    Iverson, D. L.

    1994-01-01

    Fault tree and digraph models are frequently used for system failure analysis. Both type of models represent a failure space view of the system using AND and OR nodes in a directed graph structure. Fault trees must have a tree structure and do not allow cycles or loops in the graph. Digraphs allow any pattern of interconnection between loops in the graphs. A common operation performed on digraph and fault tree models is the calculation of minimal cut sets. A cut set is a set of basic failures that could cause a given target failure event to occur. A minimal cut set for a target event node in a fault tree or digraph is any cut set for the node with the property that if any one of the failures in the set is removed, the occurrence of the other failures in the set will not cause the target failure event. CUTSETS will identify all the minimal cut sets for a given node. The CUTSETS package contains programs that solve for minimal cut sets of fault trees and digraphs using object-oriented programming techniques. These cut set codes can be used to solve graph models for reliability analysis and identify potential single point failures in a modeled system. The fault tree minimal cut set code reads in a fault tree model input file with each node listed in a text format. In the input file the user specifies a top node of the fault tree and a maximum cut set size to be calculated. CUTSETS will find minimal sets of basic events which would cause the failure at the output of a given fault tree gate. The program can find all the minimal cut sets of a node, or minimal cut sets up to a specified size. The algorithm performs a recursive top down parse of the fault tree, starting at the specified top node, and combines the cut sets of each child node into sets of basic event failures that would cause the failure event at the output of that gate. Minimal cut set solutions can be found for all nodes in the fault tree or just for the top node. The digraph cut set code uses the same

  13. Model-based setting of inspiratory pressure and respiratory rate in pressure-controlled ventilation.

    PubMed

    Schranz, C; Becher, T; Schädler, D; Weiler, N; Möller, K

    2014-03-01

    Mechanical ventilation carries the risk of ventilator-induced-lung-injury (VILI). To minimize the risk of VILI, ventilator settings should be adapted to the individual patient properties. Mathematical models of respiratory mechanics are able to capture the individual physiological condition and can be used to derive personalized ventilator settings. This paper presents model-based calculations of inspiration pressure (pI), inspiration and expiration time (tI, tE) in pressure-controlled ventilation (PCV) and a retrospective evaluation of its results in a group of mechanically ventilated patients. Incorporating the identified first order model of respiratory mechanics in the basic equation of alveolar ventilation yielded a nonlinear relation between ventilation parameters during PCV. Given this patient-specific relation, optimized settings in terms of minimal pI and adequate tE can be obtained. We then retrospectively analyzed data from 16 ICU patients with mixed pathologies, whose ventilation had been previously optimized by ICU physicians with the goal of minimization of inspiration pressure, and compared the algorithm's 'optimized' settings to the settings that had been chosen by the physicians. The presented algorithm visualizes the patient-specific relations between inspiration pressure and inspiration time. The algorithm's calculated results highly correlate to the physician's ventilation settings with r = 0.975 for the inspiration pressure, and r = 0.902 for the inspiration time. The nonlinear patient-specific relations of ventilation parameters become transparent and support the determination of individualized ventilator settings according to therapeutic goals. Thus, the algorithm is feasible for a variety of ventilated ICU patients and has the potential of improving lung-protective ventilation by minimizing inspiratory pressures and by helping to avoid the build-up of clinically significant intrinsic positive end-expiratory pressure.

  14. Masting by Betula-species; applying the resource budget model to north European data sets

    NASA Astrophysics Data System (ADS)

    Ranta, Hanna; Oksanen, Annukka; Hokkanen, Tatu; Bondestam, Kristoffer; Heino, Saini

    2005-01-01

    Masting, the intermittent production of large crops of flowers by a plant population, is a common feature among trees in boreal and temperate forests. The pollen of many broadleaved trees causes allergic diseases, which are major causes of increasing health-care costs in industrialised countries. As the prevalence and severity of allergic diseases are connected with the concentrations of airborne pollen, an universal model predicting the intensity of the coming flowering would be a valuable tool for pollen information services, and ultimately for allergic people and allergologists. We investigated whether a resource budget model created in Japan explains the fluctuations in the annual pollen sums of Betula-species in north European data sets (10 12 years at 4 sites, 20 years at 10 sites). Using the shorter data sets, the model explained 76 92% of the annual fluctuations at five study sites. Using the 20-year data set, the percentage for southern Finland was much lower, only 48%, compared with the 85% of the 12-year data set. The annual pollen sums have been higher during the 1990s than in the 1980s, which may explain the ineffectiveness of the model, while applied to the 20-year data set. Our results support the resource budget model: the masting of birch species is regulated by weather factors together with the system of resource allocation among years. The model can serve pollen information service. However, only the 10 most recent years should be used to avoid interference from trends in changing vegetation and/or climate.

  15. Data sets for snow cover monitoring and modelling from the National Snow and Ice Data Center

    NASA Astrophysics Data System (ADS)

    Holm, M.; Daniels, K.; Scott, D.; McLean, B.; Weaver, R.

    2003-04-01

    A wide range of snow cover monitoring and modelling data sets are pending or are currently available from the National Snow and Ice Data Center (NSIDC). In-situ observations support validation experiments that enhance the accuracy of remote sensing data. In addition, remote sensing data are available in near-real time, providing coarse-resolution snow monitoring capability. Time series data beginning in 1966 are valuable for modelling efforts. NSIDC holdings include SMMR and SSM/I snow cover data, MODIS snow cover extent products, in-situ and satellite data collected for NASA's recent Cold Land Processes Experiment, and soon-to-be-released ASMR-E passive microwave products. The AMSR-E and MODIS sensors are part of NASA's Earth Observing System flying on the Terra and Aqua satellites Characteristics of these NSIDC-held data sets, appropriateness of products for specific applications, and data set access and availability will be presented.

  16. Knowledge discovery in clinical databases based on variable precision rough set model.

    PubMed Central

    Tsumoto, S.; Ziarko, W.; Shan, N.; Tanaka, H.

    1995-01-01

    Since a large amount of clinical data are being stored electronically, discovery of knowledge from such clinical databases is one of the important growing research area in medical informatics. For this purpose, we develop KDD-R (a system for Knowledge Discovery in Databases using Rough sets), an experimental system for knowledge discovery and machine learning research using variable precision rough sets (VPRS) model, which is an extension of original rough set model. This system works in the following steps. First, it preprocesses databases and translates continuous data into discretized ones. Second, KDD-R checks dependencies between attributes and reduces spurious data. Third, the system computes rules from reduced databases. Finally, fourth, it evaluates decision making. For evaluation, this system is applied to a clinical database of meningoencephalitis, whose computational results show that several new findings are obtained. PMID:8563283

  17. Evaluation of Tricuspid Annular Plane Systolic Excursion Measured with Cardiac Magnetic Resonance Imaging in Pediatric Patients with Tetralogy of Fallot

    PubMed Central

    Soslow, Jonathan H.; Usoro, Emem; Wang, Li; Parra, David A.

    2015-01-01

    Background Aneurysmal dilation of the right ventricular outflow tract complicates assessment of right ventricular function in patients with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is commonly used to estimate ejection fraction. We hypothesized that tricuspid annular plane systolic excursion measured by cardiac magnetic resonance imaging approximates global and segmental right ventricular function, specifically right ventricular sinus ejection fraction, in pediatric patients with repaired tetralogy of Fallot. Methods Tricuspid annular plane systolic excursion was measured retrospectively on cardiac magnetic resonance images in 54 patients with repaired tetralogy of Fallot. Values were compared with right ventricular global, sinus, and infundibular ejection fractions. Tricuspid annular plane systolic excursion was: 1) indexed to body surface area, 2) converted into a fractional value, and 3) converted into published pediatric Z-scores. Results Tricuspid annular plane systolic excursion measurements had good agreement between observers. Right ventricular ejection fraction did not correlate with the absolute or indexed tricuspid annular plane systolic excursion and correlated weakly with fractional tricuspid annular plane systolic excursion (r=0.41 and p=0.002). Segmental right ventricular function did not appreciably improve correlation with any of the tricuspid annular plane systolic excursion measures. Pediatric Z-scores were unable to differentiate patients with normal and abnormal right ventricular function. Conclusions Tricuspid annular plane systolic excursion measured on cardiac magnetic resonance imaging correlates poorly with global and segmental right ventricular ejection fraction in pediatric patients with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is an unreliable approximation of right ventricular function in this patient population. PMID:26279488

  18. The Palaeocene-Eocene carbon isotope excursion: constraints from individual shell planktonic foraminifer records.

    PubMed

    Zachos, James C; Bohaty, Steven M; John, Cedric M; McCarren, Heather; Kelly, Daniel C; Nielsen, Tina

    2007-07-15

    The Palaeocene-Eocene thermal maximum (PETM) is characterized by a global negative carbon isotope excursion (CIE) and widespread dissolution of seafloor carbonate sediments. The latter feature supports the hypothesis that the PETM and CIE were caused by the rapid release of a large mass (greater than 2000Gt C) of 12C-enriched carbon. The source of this carbon, however, remains a mystery. Possible sources include volcanically driven thermal combustion of organic-rich sediment, dissociation of seafloor methane hydrates and desiccation and oxidation of soil/sediment organics. A key constraint on the source(s) is the rate at which the carbon was released. Fast rates would be consistent with a catastrophic event, e.g. massive methane hydrate dissociation, whereas slower rates might implicate other processes. The PETM carbon flux is currently constrained by high-resolution marine and terrestrial records of the CIE. In pelagic bulk carbonate records, the onset of the CIE is often expressed as a single- or multiple-step excursion extending over 10(4) years. Individual planktonic shell records, in contrast, always show a single-step CIE, with either pre-excursion or excursion isotope values, but no transition values. Benthic foraminifera records, which are less complete owing to extinction and diminutive assemblages, show a delayed excursion. Here, we compile and evaluate the individual planktonic shell isotope data from several localities. We find that the most expanded records consistently show a bimodal isotope distribution pattern regardless of location, water depth or depositional facies. This suggests one of several possibilities: (i) the isotopic composition of the surface ocean/atmosphere declined in a geologic instant (<500yr), (ii) that during the onset of the CIE, most shells of mixed-layer planktonic foraminifera were dissolved, or (iii) the abundances or shell production of these species temporarily declined, possibly due to initial pH changes.

  19. Timing of Carbon isotope excursions during the late Triassic and early Jurassic

    NASA Astrophysics Data System (ADS)

    Yager, J. A.; West, A. J.; Corsetti, F. A.; Berelson, W.; Bottjer, D. J.; Rosas, S.

    2015-12-01

    The emplacement of the Central Atlantic Magmatic Province during the late Triassic and early Jurassic is implicated in the end-Triassic mass extinction and is associated with dramatic increases in atmospheric pCO2. Changes in the isotopic composition of CO2 as recorded on land and in the ocean have been observed in many sections worldwide, but the timing and causes of the changes are debated. Recent high-resolution ash bed dating (Schaltegger et al., 2008; Schoene et al., 2010; Guex et al., 2012; Wotzlaw et al., 2014) from a continuous Rhaetian-Hettangian section near Levanto, Peru, provide an opportunity to understand the duration of these carbon cycle disruptions, and ammonite biostratigraphy allows comparison to other sections. We measured % organic carbon and % inorganic carbon along with δ13Corganic and δ13Ccarbonate at the section near Levanto. We find a series of δ13Corganic excursions that are similar to those found in other Triassic-Jurassic successions, both from the Tethyan (St. Audrie's Bay, UK) and Panthalassic oceans (Kennecott Point, CAN), pointing to the global extent of these changes. At Levanto, we can identify a brief, initial positive carbon isotope excursion followed first by a sharp negative excursion that coincides with the last appearance of Triassic ammonites, and then a more extended positive carbon isotope excursion that extends into the initial Jurassic recovery. Using the ash bed dates from Levanto, we are able for the first time to estimate robustly the duration of each carbon isotope excursion across the Triassic-Jurassic interval. These estimates of durations aid in our understanding of timing and causes of carbon cycle perturbations associated with the emplacement of CAMP and its relation to mass extinction.

  20. Median nerve excursion in response to wrist movement after endoscopic and open carpal tunnel release.

    PubMed

    Tüzüner, Serdar; Inceoğlu, Salih; Bilen, F Erkal

    2008-09-01

    To compare the perioperative kinematic effects of endoscopic versus open carpal tunnel release on longitudinal excursion (gliding) and volar displacement (bowstringing) of the median nerve at the wrist region in patients with idiopathic primary carpal tunnel syndrome. Sixteen hands of 13 patients were randomly assigned into 2 groups (group 1, endoscopic; group 2, open carpal tunnel release). For the measurement of gliding and bowstringing of the median nerve, a metallic marker was used. Before and after the division of the transverse carpal ligament, longitudinal excursion and volar displacement of the median nerve were calculated based on fluoroscopic imaging for each wrist. Movement was analyzed for the measurement of the marker locations. The mean prerelease median nerve excursion during wrist range of motion was 20 mm (range, 10-28) in group 1 and 21 mm (range, 16-31 mm) in group 2. The mean postrelease median nerve excursion during wrist range of motion was 20 mm (range, 13-29) in group 1 and 18 mm (range, 8-26 mm) in group 2. There was no statistically significant difference in pre- and postrelease longitudinal excursion changes between the groups (p = .916 and p = .674, respectively). The mean prerelease volar displacement of the median nerve during wrist range of motion was 3 mm in group 1 and 4 mm in group 2; the postrelease mean values were 2 mm and 5 mm, respectively. There was no statistically significant difference between the groups with regard to pre- and postrelease volar displacement changes of the median nerve (p = .372 and p = .103, respectively). This study demonstrated that the endoscopic release and open carpal tunnel release produce similar perioperative effects on longitudinal and volar movements of the median nerve.

  1. Modulation of chest wall intermuscular coherence: effects of lung volume excursion and transcranial direct current stimulation.

    PubMed

    Tomczak, Corey R; Greidanus, Krista R; Boliek, Carol A

    2013-08-01

    Chest wall muscle recruitment varies as a function of the breathing task performed. However, the cortical control of the chest wall muscles during different breathing tasks is not known. We studied chest wall intermuscular coherence during various task-related lung volume excursions in 10 healthy adults (34 ± 15 yr; 2 men, 8 women) and determined if transcranial direct current stimulation (tDCS) could modulate chest wall intermuscular coherence during these tasks. Simultaneous assessment of regional intercostal and oblique electromyographic activity was measured while participants performed standardized tidal breathing, speech, maximum phonation, and vital capacity tasks. Lung volume and chest wall kinematics were determined using variable inductance plethysmography. We found that chest wall area of intermuscular coherence was greater during tidal and speech breathing compared with phonation and vital capacity (all P < 0.05) and between tidal breathing compared with speech breathing (P < 0.05). Anodal tDCS increased chest wall area of intermuscular coherence from 0.04 ± 0.09 prestimulation to 0.18 ± 0.19 poststimulation for vital capacity (P < 0.05). Sham tDCS and cathodal tDCS had no effect on coherence during lung volume excursions. Chest wall kinematics were not affected by tDCS. Our findings indicate that lung volume excursions about the midrange of vital capacity elicit a greater area of chest wall intermuscular coherence compared with lung volume excursions spanning the entire range of vital capacity in healthy adults. Our findings also demonstrate that brief tDCS may modulate the cortical control of the chest wall muscles in a stimulation- and lung volume excursion task-dependent manner but does not affect chest wall kinematics in healthy adults.

  2. Into the deep: the functionality of mesopelagic excursions by an oceanic apex predator.

    PubMed

    Howey, Lucy A; Tolentino, Emily R; Papastamatiou, Yannis P; Brooks, Edward J; Abercrombie, Debra L; Watanabe, Yuuki Y; Williams, Sean; Brooks, Annabelle; Chapman, Demian D; Jordan, Lance K B

    2016-08-01

    Comprehension of ecological processes in marine animals requires information regarding dynamic vertical habitat use. While many pelagic predators primarily associate with epipelagic waters, some species routinely dive beyond the deep scattering layer. Actuation for exploiting these aphotic habitats remains largely unknown. Recent telemetry data from oceanic whitetip sharks (Carcharhinus longimanus) in the Atlantic show a strong association with warm waters (>20°C) less than 200 m. Yet, individuals regularly exhibit excursions into the meso- and bathypelagic zone. In order to examine deep-diving behavior in oceanic whitetip sharks, we physically recovered 16 pop-up satellite archival tags and analyzed the high-resolution depth and temperature data. Diving behavior was evaluated in the context of plausible functional behavior hypotheses including interactive behaviors, energy conservation, thermoregulation, navigation, and foraging. Mesopelagic excursions (n = 610) occurred throughout the entire migratory circuit in all individuals, with no indication of site specificity. Six depth-versus-time descent and ascent profiles were identified. Descent profile shapes showed little association with examined environmental variables. Contrastingly, ascent profile shapes were related to environmental factors and appear to represent unique behavioral responses to abiotic conditions present at the dive apex. However, environmental conditions may not be the sole factors influencing ascents, as ascent mode may be linked to intentional behaviors. While dive functionality remains unconfirmed, our study suggests that mesopelagic excursions relate to active foraging behavior or navigation. Dive timing, prey constituents, and dive shape support foraging as the most viable hypothesis for mesopelagic excursions, indicating that the oceanic whitetip shark may regularly survey extreme environments (deep depths, low temperatures) as a foraging strategy. At the apex of these deep

  3. Effect of load excursions and specimen thickness on crack closure measurements

    SciTech Connect

    McMaster, F.J.; Smith, D.J.

    1999-07-01

    The effects of simple load excursions on fatigue crack growth and crack closure measurements in aluminum alloy 2024-T351 are presented. The crack closure loads were measured local to the crack tip in 6-mm and 14-mm-thick specimens, using an Elbert type gage for measuring crack-tip opening displacement (CTOD). All specimens were manufactured from a single lot of 15.7-mm-thick plate. Preliminary tests to establish the level of crack closure for a given level of remote constant-amplitude loading were also undertaken, with consistently different levels of crack opening and closing loads observed. Crack opening and closing stresses obtained from the Elber-type (CTOD) gage, when compared with those from a (global) clip gage, showed identical results for opening stresses, but crack closing stresses were approximately 15% to 20% higher in the CTOD measurements. The results apparently contradict many analytical closure models, which have crack closing stresses lower than crack opening stresses. Simple overload, underload and over/underload cycles were performed. Differences in the number of post-overload retardation cycles for the two thicknesses, in the single overload test, were obtained. It was found that the 6-mm-thick specimen's fatigue life was two times larger than for the 14-mm-thick specimen. The measured opening stresses were found to be in general agreement with the trends obtained for the fatigue crack growth results. Greater fatigue lives were obtained in the overload tests, with subsequent higher crack opening stresses measured. After a certain number of cycles following an overload, constant-amplitude crack growth rates were restored. However, the crack opening stresses did not return to the preoverload constant-amplitude values, but increased relative to the preoverload constant-amplitude crack opening stresses.

  4. Galectin-3 Reflects Mitral Annular Plane Systolic Excursion Being Assessed by Cardiovascular Magnetic Resonance Imaging

    PubMed Central

    Kim, Seung-Hyun; Natale, Michele; Hoffmann, Julia; Reckord, Nadine; Hoffmann, Ursula; Budjan, Johannes; Henzler, Thomas; Papavassiliu, Theano; Borggrefe, Martin; Bertsch, Thomas; Akin, Ibrahim

    2016-01-01

    Background. This study investigates whether serum levels of galectin-3 may reflect impaired mitral annular plane systolic excursion (MAPSE) in patients undergoing cardiac magnetic resonance imaging (cMRI). Methods. Patients undergoing cMRI during routine clinical care were included prospectively within an all-comers design. Blood samples for biomarker measurements were collected within 24 hours following cMRI. Statistical analyses were performed in all patients and in three subgroups according to MAPSE (MAPSE I: ≥11 mm, MAPSE II: ≥8 mm–<11 mm, and MAPSE III: <8 mm). Patients with right ventricular dysfunction (<50%) were excluded. Results. 84 patients were included in the study. Median LVEF was 59% (IQR 51–64%). Galectin-3 correlated significantly with NT-proBNP (r = 0.42, p = 0.0001). Galectin-3 increased significantly according to the different stages of impaired MAPSE (p = 0.006) and was able to discriminate both patients with impaired MAPSE <11 mm (area under the curve (AUC) = 0.645, p = 0.024) and <8 mm (AUC = 0.733, p = 0.003). Combining galectin-3 with NT-proBNP improved discrimination of MAPSE <8 mm (AUC 0.803, p = 0.0001). In multivariable logistic regression models galectin-3 was still associated with impaired MAPSE (MAPSE < 11 mm: odds ratio (OR) = 3.53, p = 0.018; MAPSE < 8 mm: OR = 3.18, p = 0.06). Conclusions. Galectin-3 reflects MAPSE being assessed by cardiac MRI. PMID:28044067

  5. Environmental forcing of terrestrial carbon isotope excursion amplification across five Eocene hyperthermals

    NASA Astrophysics Data System (ADS)

    Bowen, G. J.; Abels, H.

    2015-12-01

    Abrupt changes in the isotope composition of exogenic carbon pools accompany many major episodes of global change in the geologic record. The global expression of this change in substrates that reflect multiple carbon pools provides important evidence that many events reflect persistent, global redistribution of carbon between reduced and oxidized stocks. As the diversity of records documenting any event grows, however, discrepancies in the expression of carbon isotope change among substrates are almost always revealed. These differences in magnitude, pace, and pattern of change can complicate interpretations of global carbon redistribution, but under ideal circumstances can also provide additional information on changes in specific environmental and biogeochemical systems that accompanied the global events. Here we evaluate possible environmental influences on new terrestrial records of the negative carbon isotope excursions (CIEs) associated with multiple hyperthermals of the Early Eocene, which show a common pattern of amplified carbon isotope change in terrestrial paleosol carbonate records relative to that recorded in marine substrates. Scaling relationships between climate and carbon-cycle proxies suggest that that the climatic (temperature) impact of each event scaled proportionally with the magnitude of its marine CIE, likely implying that all events involved release of reduced carbon with a similar isotopic composition. Amplification of the terrestrial CIEs, however, does not scale with event magnitude, being proportionally less for the first, largest event (the PETM). We conduct a sensitivity test of a coupled plant-soil carbon isotope model to identify conditions that could account for the observed CIE scaling. At least two possibilities consistent with independent lines of evidence emerge: first, varying effects of pCO2 change on photosynthetic carbon isotope discrimination under changing background pCO2, and second, contrasting changes in regional

  6. Community environmental education: three models of organization for PSD Set II. Final report

    SciTech Connect

    Burke, P.

    1980-06-01

    The study undertakes an examination of models of community environmental education relevant for PSD Set II. Issues of sufficient technical information, aspects of citizen participation, organizational theory, and politics are examined. Community environmental education is deemed to be feasible here, and three potential organizational models are presented: one focuses on the Cooperative Extension Service, one on regional planning bodies, and one on the community school network.

  7. Mentoring for junior medical faculty: Existing models and suggestions for low-resource settings.

    PubMed

    Menon, Vikas; Muraleedharan, Aparna; Bhat, Ballambhattu Vishnu

    2016-02-01

    Globally, there is increasing recognition about the positive benefits and impact of mentoring on faculty retention rates, career satisfaction and scholarly output. However, emphasis on research and practice of mentoring is comparatively meagre in low and middle income countries. In this commentary, we critically examine two existing models of mentorship for medical faculty and offer few suggestions for an integrated hybrid model that can be adapted for use in low resource settings. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Quantifying tensions between CMB and distance data sets in models with free curvature or lensing amplitude

    NASA Astrophysics Data System (ADS)

    Grandis, S.; Rapetti, D.; Saro, A.; Mohr, J. J.; Dietrich, J. P.

    2016-12-01

    Recent measurements of the cosmic microwave background (CMB) by the Planck Collaboration have produced arguably the most powerful observational evidence in support of the standard model of cosmology, i.e. the spatially flat ΛCDM paradigm. In this work, we perform model selection tests to examine whether the base CMB temperature and large scale polarization anisotropy data from Planck 2015 (P15; Planck Collaboration XIII) prefer any of eight commonly used one-parameter model extensions with respect to flat ΛCDM. We find a clear preference for models with free curvature, ΩK, or free amplitude of the CMB lensing potential, AL. We also further develop statistical tools to measure tension between data sets. We use a Gaussianization scheme to compute tensions directly from the posterior samples using an entropy-based method, the surprise, as well as a calibrated evidence ratio presented here for the first time. We then proceed to investigate the consistency between the base P15 CMB data and six other CMB and distance data sets. In flat ΛCDM we find a 4.8σ tension between the base P15 CMB data and a distance ladder measurement, whereas the former are consistent with the other data sets. In the curved ΛCDM model we find significant tensions in most of the cases, arising from the well-known low power of the low-ℓ multipoles of the CMB data. In the flat ΛCDM+AL model, however, all data sets are consistent with the base P15 CMB observations except for the CMB lensing measurement, which remains in significant tension. This tension is driven by the increased power of the CMB lensing potential derived from the base P15 CMB constraints in both models, pointing at either potentially unresolved systematic effects or the need for new physics beyond the standard flat ΛCDM model.

  9. West Adriatic Coastal Water Excursions into the East Adriatic

    DTIC Science & Technology

    2009-01-15

    than twoweeks, theWAC eddies and filaments grew freely and had enough time to reach middle east Adriatic waters. Navy Coastal Ocean Model (NCOM...simplified channel model suggests that the presence of the escarpment is a critical factor for producing cross-basin exchange of the coastal current following

  10. Model choice for phylogeographic inference using a large set of models.

    PubMed

    Pelletier, Tara A; Carstens, Bryan C

    2014-06-01

    Model-based analyses are common in phylogeographic inference because they parameterize processes such as population division, gene flow and expansion that are of interest to biologists. Approximate Bayesian computation is a model-based approach that can be customized to any empirical system and used to calculate the relative posterior probability of several models, provided that suitable models can be identified for comparison. The question of how to identify suitable models is explored using data from Plethodon idahoensis, a salamander that inhabits the North American inland northwest temperate rainforest. First, we conduct an ABC analysis using five models suggested by previous research, calculate the relative posterior probabilities and find that a simple model of population isolation has the best fit to the data (PP=0.70). In contrast to this subjective choice of models to include in the analysis, we also specify models in a more objective manner by simulating prior distributions for 143 models that included panmixia, population isolation, change in effective population size, migration and range expansion. We then identify a smaller subset of models for comparison by generating an expectation of the highest posterior probability that a false model is likely to achieve due to chance and calculate the relative posterior probabilities of only those models that exceed this expected level. A model that parameterized divergence with population expansion and gene flow in one direction offered the best fit to the P. idahoensis data (in contrast to an isolation-only model from the first analysis). Our investigation demonstrates that the determination of which models to include in ABC model choice experiments is a vital component of model-based phylogeographic analysis.

  11. Paradigms, Mental Models, and Mind-Sets: Triple Barriers to Transformational Change in School Systems

    ERIC Educational Resources Information Center

    Duffy, Francis M.

    2014-01-01

    This article presents a simile for understanding the power of paradigms, mental models, and mind-sets as religion-like phenomena. The author clarifies the meaning of the three phenomena to help readers to see how the phenomena become significant sources of resistance to change. He concludes by outlining a paradigm-shifting process to assist…

  12. Brief Report: Predictors of Outcomes in the Early Start Denver Model Delivered in a Group Setting

    ERIC Educational Resources Information Center

    Vivanti, Giacomo; Dissanayake, Cheryl; Zierhut, Cynthia; Rogers, Sally J.

    2013-01-01

    There is a paucity of studies that have looked at factors associated with responsiveness to interventions in preschoolers with autism spectrum disorder (ASD). We investigated learning profiles associated with response to the Early Start Denver Model delivered in a group setting. Our preliminary results from 21 preschool children with an ASD aged…

  13. Breaking Bad News in Counseling: Applying the PEWTER Model in the School Setting

    ERIC Educational Resources Information Center

    Keefe-Cooperman, Kathleen; Brady-Amoon, Peggy

    2013-01-01

    Breaking bad news is a stressful experience for counselors and clients. In this article, the PEWTER (Prepare, Evaluate, Warning, Telling, Emotional Response, Regrouping) model (Nardi & Keefe-Cooperman, 2006) is used as a guide to facilitate the process of a difficult conversation and promote client growth in a school setting. In this…

  14. Analyzing Academic Achievement of Junior High School Students by an Improved Rough Set Model

    ERIC Educational Resources Information Center

    Pai, Ping-Feng; Lyu, Yi-Jia; Wang, Yu-Min

    2010-01-01

    Rough set theory (RST) is an emerging technique used to deal with problems in data mining and knowledge acquisition. However, the RST approach has not been widely explored in the field of academic achievement. This investigation developed an improved RST (IMRST) model, which employs linear discriminant analysis to determine a reduct of RST, and…

  15. Breaking Bad News in Counseling: Applying the PEWTER Model in the School Setting

    ERIC Educational Resources Information Center

    Keefe-Cooperman, Kathleen; Brady-Amoon, Peggy

    2013-01-01

    Breaking bad news is a stressful experience for counselors and clients. In this article, the PEWTER (Prepare, Evaluate, Warning, Telling, Emotional Response, Regrouping) model (Nardi & Keefe-Cooperman, 2006) is used as a guide to facilitate the process of a difficult conversation and promote client growth in a school setting. In this…

  16. Analyzing Academic Achievement of Junior High School Students by an Improved Rough Set Model

    ERIC Educational Resources Information Center

    Pai, Ping-Feng; Lyu, Yi-Jia; Wang, Yu-Min

    2010-01-01

    Rough set theory (RST) is an emerging technique used to deal with problems in data mining and knowledge acquisition. However, the RST approach has not been widely explored in the field of academic achievement. This investigation developed an improved RST (IMRST) model, which employs linear discriminant analysis to determine a reduct of RST, and…

  17. Video Self-Modeling: A Job Skills Intervention with Individuals with Intellectual Disability in Employment Settings

    ERIC Educational Resources Information Center

    Goh, Ailsa E.; Bambara, Linda M.

    2013-01-01

    The purpose of this study was to explore the effectiveness of video self-modeling (VSM) to teach chained job tasks to individuals with intellectual disability in community-based employment settings. Initial empirical evaluations have demonstrated that VSM when used in combination with other instructional strategies, are effective methods to teach…

  18. Technology Adoption Applied to Educational Settings: Predicting Interventionists' Use of Video-Self Modeling

    ERIC Educational Resources Information Center

    Heckman, Andrew R.

    2010-01-01

    Technology provides educators with a significant advantage in working with today's students. One particular application of technology for the purposes of academic and behavioral interventions is the use of video self-modeling (VSM). Although VSM is an evidence-based intervention, it is rarely used in educational settings. The present research…

  19. Paradigms, Mental Models, and Mind-Sets: Triple Barriers to Transformational Change in School Systems

    ERIC Educational Resources Information Center

    Duffy, Francis M.

    2014-01-01

    This article presents a simile for understanding the power of paradigms, mental models, and mind-sets as religion-like phenomena. The author clarifies the meaning of the three phenomena to help readers to see how the phenomena become significant sources of resistance to change. He concludes by outlining a paradigm-shifting process to assist…

  20. A long-term data set for hydrologic modeling in a snow-dominated mountain catchment

    USDA-ARS?s Scientific Manuscript database

    An hourly modeling data set is presented for the water years 1984 through 2008 for a snow-dominated headwater catchment. Meteorological forcing data and GIS watershed characteristics are described and provided. The meteorological data are measured at two sites within the catchment, and include pre...

  1. Technology Adoption Applied to Educational Settings: Predicting Interventionists' Use of Video-Self Modeling

    ERIC Educational Resources Information Center

    Heckman, Andrew R.

    2010-01-01

    Technology provides educators with a significant advantage in working with today's students. One particular application of technology for the purposes of academic and behavioral interventions is the use of video self-modeling (VSM). Although VSM is an evidence-based intervention, it is rarely used in educational settings. The present research…

  2. Video Self-Modeling: A Job Skills Intervention with Individuals with Intellectual Disability in Employment Settings

    ERIC Educational Resources Information Center

    Goh, Ailsa E.; Bambara, Linda M.

    2013-01-01

    The purpose of this study was to explore the effectiveness of video self-modeling (VSM) to teach chained job tasks to individuals with intellectual disability in community-based employment settings. Initial empirical evaluations have demonstrated that VSM when used in combination with other instructional strategies, are effective methods to teach…

  3. Goal Setting and Performance Evaluation with Different Starting Positions: The Modeling Dilemma.

    ERIC Educational Resources Information Center

    Pray, Thomas F.; Gold, Steven

    1991-01-01

    Reviews 10 computerized business simulations used to teach business policy courses, discusses problems with measuring performance, and presents a statistically based approach to assessing performance that permits individual team goal setting as part of the computer model, and allows simulated firms to start with different financial and operating…

  4. Invariance, Artifact, and the Psychological Setting of Rasch's Model: Comments on Engelhard

    ERIC Educational Resources Information Center

    Michell, Joel

    2008-01-01

    In the following, I confine my comments mainly to the issue of invariance in relation to Rasch's model for dichotomous, ability test items. "It is senseless to seek in the logical process of mathematical elaboration a psychologically significant precision that was not present in the psychological setting of the problem." (Boring, 1920)

  5. A paleomagnetic record of the last 640 kyr from an eastern Mediterranean piston core and a review of geomagnetic excursions in the Brunhes

    NASA Astrophysics Data System (ADS)

    Oda, H.; Dekkers, M. J.; Langereis, C. G.; Lourens, L.; Heslop, D.

    2004-12-01

    Core KC01 (25.93 m long) was taken from a small ridge on the lower slope of the southern Calabrian Ridge (Pisano Plateau, 36deg15.25'N, 17deg44.34'E, 3643m water depth) during cruise MD69 of the French R/V Marion Dufresne in June-July 1991. The sediment consists of hemipelagic sediments with intercalated sapropel and tephra layers. They form an alternation of grey, greenish, olive-coloured, yellowish, white and beige shades. Sapropel layers are black to dark green. Paleomagnetic samples (6.4 cm3 cubes) were taken from the half split cores and measurements of the natural remanent magnetization was conducted at Utrecht University with a DC SQUID magnetometer (2G Enterprises model 740-R). Stepwise alternating field demagnetization was done at 8-11 steps up to 60-80 mT on each sample. Core KC01 (37.04 m long) was taken as a companion core from core KC01B at the same locality, earlier subjected to magnetostratigraphic work (Langereis et al., 1997). Langereis et al. (1997) established an age model based on the matching of (ghost-)sapropels with insolation minima. They applied the 65degN summer insolation calculated from the astronomical solution La90 (Laskar 1990; Laskar et al., 1993) as target curve and included a time lag of 3-kyr - based on the age difference between the radiocarbon dated midpoint of S1 at 8.5 ka and the insolation maximum at 11.5 ka following the method by Lourens et al. (1996). Lourens (2004) modified the astronomical chronology established by Langereis et al. (1997) and investigated the sapropel chronology on KC01B and KC01 based on high resolution colour correlation with ODP Site 964, which is 1 km away, and constructed an improved age model, which gives a better estimate for these two cores. Langereis et al. (1997) reported four excursions (CR0, CR1, CR2, CR3) with ages of 261, 318, 515, and 573 ka based on the chronology of sapropels on Core KC01B. Lourens (2004) revised the chronology of Core KC01B and redated the excursions as 260, 319, 543

  6. Index-based groundwater vulnerability mapping models using hydrogeological settings: A critical evaluation

    SciTech Connect

    Kumar, Prashant; Bansod, Baban K.S.; Debnath, Sanjit K.; Thakur, Praveen Kumar; Ghanshyam, C.

    2015-02-15

    Groundwater vulnerability maps are useful for decision making in land use planning and water resource management. This paper reviews the various groundwater vulnerability assessment models developed across the world. Each model has been evaluated in terms of its pros and cons and the environmental conditions of its application. The paper further discusses the validation techniques used for the generated vulnerability maps by various models. Implicit challenges associated with the development of the groundwater vulnerability assessment models have also been identified with scientific considerations to the parameter relations and their selections. - Highlights: • Various index-based groundwater vulnerability assessment models have been discussed. • A comparative analysis of the models and its applicability in different hydrogeological settings has been discussed. • Research problems of underlying vulnerability assessment models are also reported in this review paper.

  7. A new LPV modeling approach using PCA-based parameter set mapping to design a PSS.

    PubMed

    Jabali, Mohammad B Abolhasani; Kazemi, Mohammad H

    2017-01-01

    This paper presents a new methodology for the modeling and control of power systems based on an uncertain polytopic linear parameter-varying (LPV) approach using parameter set mapping with principle component analysis (PCA). An LPV representation of the power system dynamics is generated by linearization of its differential-algebraic equations about the transient operating points for some given specific faults containing the system nonlinear properties. The time response of the output signal in the transient state plays the role of the scheduling signal that is used to construct the LPV model. A set of sample points of the dynamic response is formed to generate an initial LPV model. PCA-based parameter set mapping is used to reduce the number of models and generate a reduced LPV model. This model is used to design a robust pole placement controller to assign the poles of the power system in a linear matrix inequality (LMI) region, such that the response of the power system has a proper damping ratio for all of the different oscillation modes. The proposed scheme is applied to controller synthesis of a power system stabilizer, and its performance is compared with a tuned standard conventional PSS using nonlinear simulation of a multi-machine power network. The results under various conditions show the robust performance of the proposed controller.

  8. Using the Many-Facet Rasch Model to Evaluate Standard-Setting Judgments: Setting Performance Standards for Advanced Placement® Examinations

    ERIC Educational Resources Information Center

    Kaliski, Pamela; Wind, Stefanie A.; Engelhard, George, Jr.; Morgan, Deanna; Plake, Barbara; Reshetar, Rosemary

    2012-01-01

    The Many-Facet Rasch (MFR) Model is traditionally used to evaluate the quality of ratings on constructed response assessments; however, it can also be used to evaluate the quality of judgments from panel-based standard setting procedures. The current study illustrates the use of the MFR Model by examining the quality of ratings obtained from a…

  9. Kinome-wide activity modeling from diverse public high-quality data sets.

    PubMed

    Schürer, Stephan C; Muskal, Steven M

    2013-01-28

    Large corpora of kinase small molecule inhibitor data are accessible to public sector research from thousands of journal article and patent publications. These data have been generated employing a wide variety of assay methodologies and experimental procedures by numerous laboratories. Here we ask the question how applicable these heterogeneous data sets are to predict kinase activities and which characteristics of the data sets contribute to their utility. We accessed almost 500,000 molecules from the Kinase Knowledge Base (KKB) and after rigorous aggregation and standardization generated over 180 distinct data sets covering all major groups of the human kinome. To assess the value of the data sets, we generated hundreds of classification and regression models. Their rigorous cross-validation and characterization demonstrated highly predictive classification and quantitative models for the majority of kinase targets if a minimum required number of active compounds or structure-activity data points were available. We then applied the best classifiers to compounds most recently profiled in the NIH Library of Integrated Network-based Cellular Signatures (LINCS) program and found good agreement of profiling results with predicted activities. Our results indicate that, although heterogeneous in nature, the publically accessible data sets are exceedingly valuable and well suited to develop highly accurate predictors for practical Kinome-wide virtual screening applications and to complement experimental kinase profiling.

  10. Truth, models, model sets, AIC, and multimodel inference: a Bayesian perspective

    USGS Publications Warehouse

    Barker, Richard J.; Link, William A.

    2015-01-01

    Statistical inference begins with viewing data as realizations of stochastic processes. Mathematical models provide partial descriptions of these processes; inference is the process of using the data to obtain a more complete description of the stochastic processes. Wildlife and ecological scientists have become increasingly concerned with the conditional nature of model-based inference: what if the model is wrong? Over the last 2 decades, Akaike's Information Criterion (AIC) has been widely and increasingly used in wildlife statistics for 2 related purposes, first for model choice and second to quantify model uncertainty. We argue that for the second of these purposes, the Bayesian paradigm provides the natural framework for describing uncertainty associated with model choice and provides the most easily communicated basis for model weighting. Moreover, Bayesian arguments provide the sole justification for interpreting model weights (including AIC weights) as coherent (mathematically self consistent) model probabilities. This interpretation requires treating the model as an exact description of the data-generating mechanism. We discuss the implications of this assumption, and conclude that more emphasis is needed on model checking to provide confidence in the quality of inference.

  11. Exhaustively characterizing feasible logic models of a signaling network using Answer Set Programming

    PubMed Central

    Guziolowski, Carito; Videla, Santiago; Eduati, Federica; Thiele, Sven; Cokelaer, Thomas; Siegel, Anne; Saez-Rodriguez, Julio

    2013-01-01

    Motivation: Logic modeling is a useful tool to study signal transduction across multiple pathways. Logic models can be generated by training a network containing the prior knowledge to phospho-proteomics data. The training can be performed using stochastic optimization procedures, but these are unable to guarantee a global optima or to report the complete family of feasible models. This, however, is essential to provide precise insight in the mechanisms underlaying signal transduction and generate reliable predictions. Results: We propose the use of Answer Set Programming to explore exhaustively the space of feasible logic models. Toward this end, we have developed caspo, an open-source Python package that provides a powerful platform to learn and characterize logic models by leveraging the rich modeling language and solving technologies of Answer Set Programming. We illustrate the usefulness of caspo by revisiting a model of pro-growth and inflammatory pathways in liver cells. We show that, if experimental error is taken into account, there are thousands (11 700) of models compatible with the data. Despite the large number, we can extract structural features from the models, such as links that are always (or never) present or modules that appear in a mutual exclusive fashion. To further characterize this family of models, we investigate the input–output behavior of the models. We find 91 behaviors across the 11 700 models and we suggest new experiments to discriminate among them. Our results underscore the importance of characterizing in a global and exhaustive manner the family of feasible models, with important implications for experimental design. Availability: caspo is freely available for download (license GPLv3) and as a web service at http://caspo.genouest.org/. Supplementary information: Supplementary materials are available at Bioinformatics online. Contact: santiago.videla@irisa.fr PMID:23853063

  12. Exhaustively characterizing feasible logic models of a signaling network using Answer Set Programming.

    PubMed

    Guziolowski, Carito; Videla, Santiago; Eduati, Federica; Thiele, Sven; Cokelaer, Thomas; Siegel, Anne; Saez-Rodriguez, Julio

    2013-09-15

    Logic modeling is a useful tool to study signal transduction across multiple pathways. Logic models can be generated by training a network containing the prior knowledge to phospho-proteomics data. The training can be performed using stochastic optimization procedures, but these are unable to guarantee a global optima or to report the complete family of feasible models. This, however, is essential to provide precise insight in the mechanisms underlaying signal transduction and generate reliable predictions. We propose the use of Answer Set Programming to explore exhaustively the space of feasible logic models. Toward this end, we have developed caspo, an open-source Python package that provides a powerful platform to learn and characterize logic models by leveraging the rich modeling language and solving technologies of Answer Set Programming. We illustrate the usefulness of caspo by revisiting a model of pro-growth and inflammatory pathways in liver cells. We show that, if experimental error is taken into account, there are thousands (11 700) of models compatible with the data. Despite the large number, we can extract structural features from the models, such as links that are always (or never) present or modules that appear in a mutual exclusive fashion. To further characterize this family of models, we investigate the input-output behavior of the models. We find 91 behaviors across the 11 700 models and we suggest new experiments to discriminate among them. Our results underscore the importance of characterizing in a global and exhaustive manner the family of feasible models, with important implications for experimental design. caspo is freely available for download (license GPLv3) and as a web service at http://caspo.genouest.org/. Supplementary materials are available at Bioinformatics online. santiago.videla@irisa.fr.

  13. Applicability domains for classification problems: Benchmarking of distance to models for Ames mutagenicity set.

    PubMed

    Sushko, Iurii; Novotarskyi, Sergii; Körner, Robert; Pandey, Anil Kumar; Cherkasov, Artem; Li, Jiazhong; Gramatica, Paola; Hansen, Katja; Schroeter, Timon; Müller, Klaus-Robert; Xi, Lili; Liu, Huanxiang; Yao, Xiaojun; Öberg, Tomas; Hormozdiari, Farhad; Dao, Phuong; Sahinalp, Cenk; Todeschini, Roberto; Polishchuk, Pavel; Artemenko, Anatoliy; Kuz'min, Victor; Martin, Todd M; Young, Douglas M; Fourches, Denis; Muratov, Eugene; Tropsha, Alexander; Baskin, Igor; Horvath, Dragos; Marcou, Gilles; Muller, Christophe; Varnek, Alexander; Prokopenko, Volodymyr V; Tetko, Igor V

    2010-12-27

    The estimation of accuracy and applicability of QSAR and QSPR models for biological and physicochemical properties represents a critical problem. The developed parameter of "distance to model" (DM) is defined as a metric of similarity between the training and test set compounds that have been subjected to QSAR/QSPR modeling. In our previous work, we demonstrated the utility and optimal performance of DM metrics that have been based on the standard deviation within an ensemble of QSAR models. The current study applies such analysis to 30 QSAR models for the Ames mutagenicity data set that were previously reported within the 2009 QSAR challenge. We demonstrate that the DMs based on an ensemble (consensus) model provide systematically better performance than other DMs. The presented approach identifies 30-60% of compounds having an accuracy of prediction similar to the interlaboratory accuracy of the Ames test, which is estimated to be 90%. Thus, the in silico predictions can be used to halve the cost of experimental measurements by providing a similar prediction accuracy. The developed model has been made publicly available at http://ochem.eu/models/1 .

  14. Many Parameter Sets in a Multicompartment Model Oscillator Are Robust to Temperature Perturbations

    PubMed Central

    Caplan, Jonathan S.; Williams, Alex H.

    2014-01-01

    Neurons in cold-blooded animals remarkably maintain their function over a wide range of temperatures, even though the rates of many cellular processes increase twofold, threefold, or many-fold for each 10°C increase in temperature. Moreover, the kinetics of ion channels, maximal conductances, and Ca2+ buffering each have independent temperature sensitivities, suggesting that the balance of biological parameters can be disturbed by even modest temperature changes. In stomatogastric ganglia of the crab Cancer borealis, the duty cycle of the bursting pacemaker kernel is highly robust between 7 and 23°C (Rinberg et al., 2013). We examined how this might be achieved in a detailed conductance-based model in which exponential temperature sensitivities were given by Q10 parameters. We assessed the temperature robustness of this model across 125,000 random sets of Q10 parameters. To examine how robustness might be achieved across a variable population of animals, we repeated this analysis across six sets of maximal conductance parameters that produced similar activity at 11°C. Many permissible combinations of maximal conductance and Q10 parameters were found over broad regions of parameter space and relatively few correlations among Q10s were observed across successful parameter sets. A significant portion of Q10 sets worked for at least 3 of the 6 maximal conductance sets (∼11.1%). Nonetheless, no Q10 set produced robust function across all six maximal conductance sets, suggesting that maximal conductance parameters critically contribute to temperature robustness. Overall, these results provide insight into principles of temperature robustness in neuronal oscillators. PMID:24695714

  15. Synthesis of clinical prediction models under different sets of covariates with one individual patient data.

    PubMed

    Yoneoka, Daisuke; Henmi, Masayuki; Sawada, Norie; Inoue, Manami

    2015-11-19

    Recently, increased development of clinical prediction models has been reported in the medical literature. However, evidence synthesis methodologies for these prediction models have not been sufficiently studied, especially for practical situations such as a meta-analyses where only aggregated summaries of important predictors are available. Also, in general, the covariate sets involved in the prediction models are not common across studies. As in ordinary model misspecification problems, dropping relevant covariates would raise potentially serious biases to the prediction models, and consequently to the synthesized results. We developed synthesizing methods for logistic clinical prediction models with possibly different sets of covariates. In order to aggregate the regression coefficient estimates from different prediction models, we adopted a generalized least squares approach with non-linear terms (a sort of generalization of multivariate meta-analysis). Firstly, we evaluated omitted variable biases in this approach. Then, under an assumption of homogeneity of studies, we developed bias-corrected estimating procedures for regression coefficients of the synthesized prediction models. Numerical evaluations with simulations showed that our approach resulted in smaller biases and more precise estimates compared with conventional methods, which use only studies with common covariates or which utilize a mean imputation method for omitted coefficients. These methods were also applied to a series of Japanese epidemiologic studies on the incidence of a stroke. Our proposed methods adequately correct the biases due to different sets of covariates between studies, and would provide precise estimates compared with the conventional approach. If the assumption of homogeneity within studies is plausible, this methodology would be useful for incorporating prior published information into the construction of new prediction models.

  16. A theoretical and computational setting for a geometrically nonlinear gradient damage modelling framework

    NASA Astrophysics Data System (ADS)

    Nedjar, B.

    The present work deals with the extension to the geometrically nonlinear case of recently proposed ideas on elastic- and elastoplastic-damage modelling frameworks within the infinitesimal theory. The particularity of these models is that the damage part of the modelling involves the gradient of damage quantity which, together with the equations of motion, are ensuing from a new formulation of the principle of virtual power. It is shown how the thermodynamics of irreversible processes is crucial in the characterization of the dissipative phenomena and in setting the convenient forms for the constitutive relations. On the numerical side, we discuss the problem of numerically integrating these equations and the implementation within the context of the finite element method is described in detail. And finally, we present a set of representative numerical simulations to illustrate the effectiveness of the proposed framework.

  17. Simultaneous financial evaluation of a complex set of capital budgeting alternatives: a mathematical model.

    PubMed

    Duncan, C S

    1983-01-01

    Capital budgeting technics provide for financial evaluation of planned purchases of equipment or other major investments. In capital budgeting, the laboratorian often is faced with a complex set of alternatives, including leasing, installment purchasing, contracting work to another laboratory, and outright purchasing. This paper presents a mathematical model useful for simultaneously evaluating the financial worth of all such alternatives under the same set of assumptions. Armed with the results of financial evaluation and evaluations of quality, turnaround time, and other patient-care factors, the laboratorian can make better decisions regarding the choice of method which, in turn, will affect the productivity of the laboratory. The model is tended for application to mutually exclusive alternatives and includes three useful capital budgeting technics: (1) payback period, (2) net present value, and (3) profitability index. The technics are demonstrated as well as a method of programming the model in financial planning software for solution by microcomputer.

  18. Towards deep inclusion for equity-oriented health research priority-setting: A working model.

    PubMed

    Pratt, Bridget; Merritt, Maria; Hyder, Adnan A

    2016-02-01

    Growing consensus that health research funders should align their investments with national research priorities presupposes that such national priorities exist and are just. Arguably, justice requires national health research priority-setting to promote health equity. Such a position is consistent with recommendations made by the World Health Organization and at global ministerial summits that health research should serve to reduce health inequalities between and within countries. Thus far, no specific requirements for equity-oriented research priority-setting have been described to guide policymakers. As a step towards the explication and defence of such requirements, we propose that deep inclusion is a key procedural component of equity-oriented research priority-setting. We offer a model of deep inclusion that was developed by applying concepts from work on deliberative democracy and development ethics. This model consists of three dimensions--breadth, qualitative equality, and high-quality non-elite participation. Deep inclusion is captured not only by who is invited to join a decision-making process but also by how they are involved and by when non-elite stakeholders are involved. To clarify and illustrate the proposed dimensions, we use the sustained example of health systems research. We conclude by reviewing practical challenges to achieving deep inclusion. Despite the existence of barriers to implementation, our model can help policymakers and other stakeholders design more inclusive national health research priority-setting processes and assess these processes' depth of inclusion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Robust group-wise rigid registration of point sets using t-mixture model

    NASA Astrophysics Data System (ADS)

    Ravikumar, Nishant; Gooya, Ali; Frangi, Alejandro F.; Taylor, Zeike A.

    2016-03-01

    A probabilistic framework for robust, group-wise rigid alignment of point-sets using a mixture of Students t-distribution especially when the point sets are of varying lengths, are corrupted by an unknown degree of outliers or in the presence of missing data. Medical images (in particular magnetic resonance (MR) images), their segmentations and consequently point-sets generated from these are highly susceptible to corruption by outliers. This poses a problem for robust correspondence estimation and accurate alignment of shapes, necessary for training statistical shape models (SSMs). To address these issues, this study proposes to use a t-mixture model (TMM), to approximate the underlying joint probability density of a group of similar shapes and align them to a common reference frame. The heavy-tailed nature of t-distributions provides a more robust registration framework in comparison to state of the art algorithms. Significant reduction in alignment errors is achieved in the presence of outliers, using the proposed TMM-based group-wise rigid registration method, in comparison to its Gaussian mixture model (GMM) counterparts. The proposed TMM-framework is compared with a group-wise variant of the well-known Coherent Point Drift (CPD) algorithm and two other group-wise methods using GMMs, using both synthetic and real data sets. Rigid alignment errors for groups of shapes are quantified using the Hausdorff distance (HD) and quadratic surface distance (QSD) metrics.

  20. PIV study of the wake of a model wind turbine transitioning between operating set points

    NASA Astrophysics Data System (ADS)

    Houck, Dan; Cowen, Edwin (Todd)

    2016-11-01

    Wind turbines are ideally operated at their most efficient tip speed ratio for a given wind speed. There is increasing interest, however, in operating turbines at other set points to increase the overall power production of a wind farm. Specifically, Goit and Meyers (2015) used LES to examine a wind farm optimized by unsteady operation of its turbines. In this study, the wake of a model wind turbine is measured in a water channel using PIV. We measure the wake response to a change in operational set point of the model turbine, e.g., from low to high tip speed ratio or vice versa, to examine how it might influence a downwind turbine. A modified torque transducer after Kang et al. (2010) is used to calibrate in situ voltage measurements of the model turbine's generator operating across a resistance to the torque on the generator. Changes in operational set point are made by changing the resistance or the flow speed, which change the rotation rate measured by an encoder. Single camera PIV on vertical planes reveals statistics of the wake at various distances downstream as the turbine transitions from one set point to another. From these measurements, we infer how the unsteady operation of a turbine may affect the performance of a downwind turbine as its incoming flow. National Science Foundation and the Atkinson Center for a Sustainable Future.

  1. Lithography yield estimation model to predict layout pattern distortions with a reduced set of lithography simulations

    NASA Astrophysics Data System (ADS)

    Gómez, Sergio; Moll, Francesc; Mauricio, Juan

    2014-03-01

    A yield estimation model to evaluate the lithography distortion in a printed layout is presented. The yield model relates the probability of non-failure of a lithography hotspot with the manufacturing yield loss. We define a lithography hotspot as a pattern construct with excessive variation under lithography printing using lithography simulations. Thereby, we propose a pattern construct classifier to reduce the set of lithography simulations necessary to estimate the litho-degradation. The application of the yield model is demonstrated for different layout configurations showing that a certain degree of layout regularity improves the manufacturing yield and increases the number of good dies per wafer.

  2. Modeling the response of exogenously crosslinked tissue to cyclic loading: The effects of permanent set.

    PubMed

    Zhang, Will; Sacks, Michael S

    2017-07-11

    Bioprosthetic heart valves (BHVs), fabricated from exogenously crosslinked collagenous tissues, remain the most popular heart valve replacement design. However, the life span of BHVs remains limited to 10-15 years, in part because the mechanisms that underlie BHV failure remain poorly understood. Experimental evidence indicates that BHVs undergo significant changes in geometry with in vivo operation, which lead to stress concentrations that can have significant impact on structural damage. These changes do not appear to be due to plastic deformation, as the leaflets only deform in the elastic regime. Moreover, structural damage was not detected by the 65 million cycle time point. Instead, we found that this nonrecoverable deformation is similar to the permanent set effect observed in elastomers, which allows the reference configuration of the material to evolve over time. We hypothesize that the scission-healing reaction of glutaraldehyde is the underlying mechanism responsible for permanent set in exogenously crosslinked soft tissues. The continuous scission-healing process of glutaraldehyde allows a portion of the exogenously crosslinked matrix, which is considered to be the non-fibrous part of the extra-cellular matrix, to be re-crosslinked in the loaded state. Thus, this mechanism for permanent set can be used to explain the time evolving mechanical response and geometry of BHVs in the early stage. To model the permanent set effect, we assume that the exogenously crosslinked matrix undergoes changes in reference configurations over time. The changes in the collagen fiber architecture due to dimensional changes allow us to predict subsequent changes in mechanical response. Results show that permanent set alone can explain and, more importantly, predict how the mechanical response of the biomaterial change with time. Furthermore, we found is no difference in permanent set rate constants between the strain controlled and the stress controlled cyclic loading

  3. GeneTopics - interpretation of gene sets via literature-driven topic models

    PubMed Central

    2013-01-01

    Background Annotation of a set of genes is often accomplished through comparison to a library of labelled gene sets such as biological processes or canonical pathways. However, this approach might fail if the employed libraries are not up to date with the latest research, don't capture relevant biological themes or are curated at a different level of granularity than is required to appropriately analyze the input gene set. At the same time, the vast biomedical literature offers an unstructured repository of the latest research findings that can be tapped to provide thematic sub-groupings for any input gene set. Methods Our proposed method relies on a gene-specific text corpus and extracts commonalities between documents in an unsupervised manner using a topic model approach. We automatically determine the number of topics summarizing the corpus and calculate a gene relevancy score for each topic allowing us to eliminate non-specific topics. As a result we obtain a set of literature topics in which each topic is associated with a subset of the input genes providing directly interpretable keywords and corresponding documents for literature research. Results We validate our method based on labelled gene sets from the KEGG metabolic pathway collection and the genetic association database (GAD) and show that the approach is able to detect topics consistent with the labelled annotation. Furthermore, we discuss the results on three different types of experimentally derived gene sets, (1) differentially expressed genes from a cardiac hypertrophy experiment in mice, (2) altered transcript abundance in human pancreatic beta cells, and (3) genes implicated by GWA studies to be associated with metabolite levels in a healthy population. In all three cases, we are able to replicate findings from the original papers in a quick and semi-automated manner. Conclusions Our approach provides a novel way of automatically generating meaningful annotations for gene sets that are directly

  4. Constitutive modeling of Radiation effects on the Permanent Set in a silicone elastomer

    SciTech Connect

    Maiti, A; Gee, R; Weisgraber, T; Chinn, S; Maxwell, R

    2008-03-10

    When a networked polymeric composite under high stress is subjected to irradiation, the resulting chemical changes like chain scissioning and cross-link formation can lead to permanent set and altered elastic modulus. Using a commercial silicone elastomer as a specific example we show that a simple 2-stage Tobolsky model in conjunction with Fricker's stress-transfer function can quantitatively reproduce all experimental data as a function of radiation dosage and the static strain at which radiation is turned on, including permanent set, stress-strain response, and net cross-linking density.

  5. Mathematical modeling of vibrations in turbogenerator sets of Sayano-Shushenskaya Hydroelectric Power Station

    NASA Astrophysics Data System (ADS)

    Leonov, G. A.; Kuznetsov, N. V.; Solovyeva, E. P.

    2016-02-01

    Oscillations in turbogenerator sets, which consist of a synchronous generator, a hydraulic turbine, and an automatic speed regulator, are investigated. This study was motivated by the emergency that took place at the Sayano-Shushenskaya Hydroelectric Power Station in 2009. During modeling of the parameters of turbogenerator sets of the Sayano-Shushenskaya Hydroelectric Power Station, the ranges corresponding to undesired oscillation regimes were determined. These ranges agree with the results of the full-scale tests of the hydropower units of the Sayano-Shushenskaya Hydroelectric Power Station performed in 1988.

  6. Elastic model-based segmentation of 3-D neuroradiological data sets.

    PubMed

    Kelemen, A; Székely, G; Gerig, G

    1999-10-01

    This paper presents a new technique for the automatic model-based segmentation of three-dimensional (3-D) objects from volumetric image data. The development closely follows the seminal work of Taylor and Cootes on active shape models, but is based on a hierarchical parametric object description rather than a point distribution model. The segmentation system includes both the building of statistical models and the automatic segmentation of new image data sets via a restricted elastic deformation of shape models. Geometric models are derived from a sample set of image data which have been segmented by experts. The surfaces of these binary objects are converted into parametric surface representations, which are normalized to get an invariant object-centered coordinate system. Surface representations are expanded into series of spherical harmonics which provide parametric descriptions of object shapes. It is shown that invariant object surface parametrization provides a good approximation to automatically determine object homology in terms of sets of corresponding sets of surface points. Gray-level information near object boundaries is represented by 1-D intensity profiles normal to the surface. Considering automatic segmentation of brain structures as our driving application, our choice of coordinates for object alignment was the well-accepted stereotactic coordinate system. Major variation of object shapes around the mean shape, also referred to as shape eigenmodes, are calculated in shape parameter space rather than the feature space of point coordinates. Segmentation makes use of the object shape statistics by restricting possible elastic deformations into the range of the training shapes. The mean shapes are initialized in a new data set by specifying the landmarks of the stereotactic coordinate system. The model elastically deforms, driven by the displacement forces across the object's surface, which are generated by matching local intensity profiles. Elastic

  7. Tree-Ring Proxies of Hydroclimate Variability in the Great Lakes Region during Cold Excursions Back to 15ka

    NASA Astrophysics Data System (ADS)

    Panyushkina, I. P.; Leavitt, S. W.

    2014-12-01

    A decade-long investigation of subfossil wood buried in glacio-fluvial, fluvial and lacustrine deposits from the U.S. Great Lakes region has resulted in a Great Lakes tree-ring network (GLTRN) comprising 47 sites dated from ca. 15 ka to 3ka. The GLTRN provides high-resolution proxies for exploration of local and regional responses to hydroclimate change at inter-annual scales during the transition from the Late Pleistocene to the Holocene. Classification of radiometric ages of GLTRN wood with relative cumulative-probability function delineates intervals and importance of hydrological changes in time and space. The overwhelming majority of wood burial events correlate with generally cold climate excursions. Forest-stand deterioration and tree mortality events at the studied sites are demonstrated to result from flooding, via river aggradation (identifying occurrence of extreme hydrologic events), rise of water table, or lake inundation. To better evaluate the special patterns of hydrological change back to 15ka, we developed four floating d13C chronologies from spruce tree rings. The length of these tree-ring proxy series that capture high-frequency moisture variability of the Great Lakes area ranges from 120 to 250 years. Our data indicate progressive wet intervals during the cold excursions precisely dated with 14C tree-ring wiggles at 13.7ka, 12.1ka, and 11.3ka that fall in the Bølling-Allerød and Pre-Boreal Interstadials, and Younger Dryas Stadial. The inter-annual and decadal variability of tree-ring moisture proxies are similar across the studied locations and time intervals. Such coherence of respective proxies may result from both local ecological stability of spruce communities or regional response to a common source of moisture at the studied time intervals and locations. This study demonstrates a potential of GLTRN proxies for modeling hydroclimatic changes at the North American continent back 15 ka.

  8. Power excursion analysis for BWR`s at high burnup

    SciTech Connect

    Diamond, D.J.; Neymoith, L.; Kohut, P.

    1996-03-01

    A study has been undertaken to determine the fuel enthalpy during a rod drop accident and during two thermal-hydraulic transients. The objective was to understand the consequences to high burnup fuel and the sources of uncertainty in the calculations. The analysis was done with RAMONA-4B, a computer code that models the neutron kinetics throughout the core along with the thermal-hydraulics in the core, vessel, and steamline. The results showed that the maximum fuel enthalpy in high burnup fuel will be affected by core design, initial conditions, and modeling assumptions. The important parameters in each of these categories are discussed in the paper.

  9. Description of a practice model for pharmacist medication review in a general practice setting

    PubMed Central

    Brandt, Mette; Hallas, Jesper; Graabæk, Trine; Pottegård, Anton

    2014-01-01

    Background Practical descriptions of procedures used for pharmacists’ medication reviews are sparse. Objective To describe a model for medication review by pharmacists tailored to a general practice setting. Methods A stepwise model is described. The model is based on data from the medical chart and clinical or laboratory data. The medication review focuses on the diagnoses of the patient instead of the individual drugs. Patient interviews are not part of the model. The model was tested in a pilot study by conducting medical reviews on 50 polypharmacy patients (i.e. receiving 7 or more drugs for regular use). Results The model contained seven main steps. Information about the patient and current treatment was collected in the first three steps, followed by identification of possible interventions related to either diagnoses or drugs in the fourth and fifth step. The sixth and seventh step concerned the reporting of interventions and the considerations of the GPs. 208 interventions were proposed among the 50 patients. The acceptance rate among the GPs was 82%. The most common interventions were lack of clinical or laboratory data (n=57, 27%) and drugs that should be discontinued as they had no indication (n=47, 23%). Most interventions were aimed at cardiovascular drugs. Conclusion We have provided a detailed description of a practical approach to pharmacists’ medication review in a GP setting. The model was tested and found to be usable, and to deliver a medication review with high acceptance rates. PMID:25243030

  10. A paradigm for human body finite element model integration from a set of regional models.

    PubMed

    Thompson, A B; Gayzik, F S; Moreno, D P; Rhyne, A C; Vavalle, N A; Stitzel, J D

    2012-01-01

    Computational modeling offers versatility, scalability, and cost advantages to researchers in the trauma and injury biomechanics communities. The Global Human Body Models Consortium (GHBMC) is a group of government, industry, and academic researchers developing human body models (HBMs) that aim to become the standard tool to meet this growing research need. The objective of this study is to present the methods used to develop the average seated male occupant model (M50, weight = 78 kg, height = 175 cm) from five separately validated body region models (BRMs). BRMs include the head, neck, thorax, abdomen, and a combined pelvis and lower extremity model. Modeling domains were split at the atlanto-occipital joint, C7-T1 boundary, diaphragm, abdominal cavity (peritoneum/retroperitoneum), and the acetabulum respectively. BRM meshes are based on a custom CAD model of the seated male built from a multi-modality imaging protocol of a volunteer subject found in literature.[1] Various meshing techniques were used to integrate the full body model (FBM) including 1-D beam and discrete element connections (e.g. ligamentous structures), 2D shell nodal connections (e.g. inferior vena cava to right atrium), 3D hexahedral nodal connections (e.g. soft tissue envelope connections between regions), and contact definitions varying from tied (muscle insertions) to sliding (liver and diaphragm contact). The model was developed in a general-purpose finite element code, LS-Dyna (LTSC, Livermore, CA) R4.2.1., and consists of 1.95 million elements and 1.3 million nodes. The element breakdown by type is 41% hexahedral, 33.7% tetrahedral, 19.5% quad shells and 5% tria shell. The integration methodology presented highlights the viability of using a collaborative development paradigm for the construction of HBMs, and will be used as template for expanding the suite of GHBMC models.

  11. ImSET 3.1: Impact of Sector Energy Technologies Model Description and User's Guide

    SciTech Connect

    Scott, Michael J.; Livingston, Olga V.; Balducci, Patrick J.; Roop, Joseph M.; Schultz, Robert W.

    2009-05-22

    This 3.1 version of the Impact of Sector Energy Technologies (ImSET) model represents the next generation of the previously-built ImSET model (ImSET 2.0) that was developed in 2005 to estimate the macroeconomic impacts of energy-efficient technology in buildings. In particular, a special-purpose version of the Benchmark National Input-Output (I-O) model was designed specifically to estimate the national employment and income effects of the deployment of Office of Energy Efficiency and Renewable Energy (EERE)–developed energy-saving technologies. In comparison with the previous versions of the model, this version features the use of the U.S. Bureau of Economic Analysis 2002 national input-output table and the central processing code has been moved from the FORTRAN legacy operating environment to a modern C++ code. ImSET is also easier to use than extant macroeconomic simulation models and incorporates information developed by each of the EERE offices as part of the requirements of the Government Performance and Results Act. While it does not include the ability to model certain dynamic features of markets for labor and other factors of production featured in the more complex models, for most purposes these excluded features are not critical. The analysis is credible as long as the assumption is made that relative prices in the economy would not be substantially affected by energy efficiency investments. In most cases, the expected scale of these investments is small enough that neither labor markets nor production cost relationships should seriously affect national prices as the investments are made. The exact timing of impacts on gross product, employment, and national wage income from energy efficiency investments is not well-enough understood that much special insight can be gained from the additional dynamic sophistication of a macroeconomic simulation model. Thus, we believe that this version of ImSET is a cost-effective solution to estimating the economic

  12. An intelligent knowledge mining model for kidney cancer using rough set theory.

    PubMed

    Durai, M A Saleem; Acharjya, D P; Kannan, A; Iyengar, N Ch Sriman Narayana

    2012-01-01

    Medical diagnosis processes vary in the degree to which they attempt to deal with different complicating aspects of diagnosis such as relative importance of symptoms, varied symptom pattern and the relation between diseases themselves. Rough set approach has two major advantages over the other methods. First, it can handle different types of data such as categorical, numerical etc. Secondly, it does not make any assumption like probability distribution function in stochastic modeling or membership grade function in fuzzy set theory. It involves pattern recognition through logical computational rules rather than approximating them through smooth mathematical functional forms. In this paper we use rough set theory as a data mining tool to derive useful patterns and rules for kidney cancer faulty diagnosis. In particular, the historical data of twenty five research hospitals and medical college is used for validation and the results show the practical viability of the proposed approach.

  13. Aerostructural Level Set Topology Optimization for a Common Research Model Wing

    NASA Technical Reports Server (NTRS)

    Dunning, Peter D.; Stanford, Bret K.; Kim, H. Alicia

    2014-01-01

    The purpose of this work is to use level set topology optimization to improve the design of a representative wing box structure for the NASA common research model. The objective is to minimize the total compliance of the structure under aerodynamic and body force loading, where the aerodynamic loading is coupled to the structural deformation. A taxi bump case was also considered, where only body force loads were applied. The trim condition that aerodynamic lift must balance the total weight of the aircraft is enforced by allowing the root angle of attack to change. The level set optimization method is implemented on an unstructured three-dimensional grid, so that the method can optimize a wing box with arbitrary geometry. Fast matching and upwind schemes are developed for an unstructured grid, which make the level set method robust and efficient. The adjoint method is used to obtain the coupled shape sensitivities required to perform aerostructural optimization of the wing box structure.

  14. Illness and injury to students on a school excursion to Peru.

    PubMed

    Shaw, Marc T M; Harding, Elizabeth; Leggat, Peter A

    2014-01-01

    School-organized travels abroad provide an opportunity for students to undertake supervised travel that reinforces scholastic study of various geographical locations under the direction and protection of experienced tour leaders and health professional support. Little is known concerning the nature of illnesses and injuries occurring on overseas school excursions. This study was designed to investigate the prevalence of injury and illness suffered by older teenagers on a school excursion to South America. In 2010, the school's tour physician (EH) diagnosed and recorded all illnesses and injuries among 29 school girls and 6 accompanying adults on a school excursion to Peru. Information recorded included age, sex, the nature of the presenting illness, number of days into the tour, the assessment of the condition, and the treatment employed during the excursion's field phase of 21 days. A total of 32 (91%) travelers sought medical advice at least once for a total of 371 consultations, resulting in 153 separate diagnoses. The mean age of the students was 16 years with six adults accompanying the students being significantly older. Primary illnesses diagnosed were related to the following systems and conditions: gastrointestinal (58, 37%), respiratory (25, 16%), altitude sickness (19, 12%), genitourinary (8, 5%), dermatological (10, 7%), trauma (7, 5%), neurological (7, 5%), anxiety or psychological adjustment (7, 5%), adverse drug reactions (4, 3%), and musculoskeletal (5, 3%). The most commonly used medications were antidiarrheal and antiemetic medication. There were six accidents during the journey resulting in minor soft-tissue injuries. There were no deaths or other major accidents requiring emergency evacuation or hospitalization. On this school excursion, the health problems encountered were consistent with those reported for other specialized tours, including expeditions and premium tours, although altitude illness needs to be carefully planned for in tours

  15. Paleomagnetic chronology of Arctic Ocean sediment cores; reversals and excursions the conundrum

    NASA Astrophysics Data System (ADS)

    Løvlie, R.; Jakobsson, M.; Backman, J.

    2003-04-01

    Chronologies of Arctic Ocean sediment cores are mainly based on interpretation of paleomagnetic inclination records. The first paleomagnetic chronology assigned zones with negative inclinations to polarity reversals (Steuerwald et al, 1968) because geomagnetic excursions at that time were a novel observation and had only been reported from lavas. Arctic Ocean sedimentation rates were thus established to be in the mm/ka-range. A general recognition of excursions as real features of the geomagnetic field emerged more than three decades later, and presently there is still no consensus regarding the number (or name), duration and age of global synchronous excursions within the Brunhes Chron. Assigning inclination records to polarity reversals or excursions is an ambiguous exercise without independent age information. Based on independently derived time frames, 11 negative inclination intervals in core 96/12-1pc from the Lomonosov Ridge were assigned to reported excursions resulting in cm/ka deposition rates (Jakobsson et al, 2000). However, the detail of the "excursional stratigraphy" in this core is problematic. The absence of two (three?) excursions in the upper 2 m of core (base MIS5) was tentatively suggested to reflect pDRM-erasing in this sandy part of the core, while the short extent of the inferred pre-Brunhes Matyuama Chron remains unaccounted for. We have recently retrieved a relative paleointensity record from a parallel core (96/B6-1pc) for alternative dating control and assessment of stratigraphic completeness and uniformity of deposition. This study indicated the presence of a hiatus of the order of 200 ka (Løvlie et al 2002). We present a paleointensity record from core 96/12-1pc and will address identification of depositional hiatuses and their significance in understanding the paleomagnetic record in Arctic Ocean cores. Steuerwald B.A., Clark D.L. and Andrew J.A., 1968. Magnetic stratigraphy and faunal patterns in Arctic Ocean sediments. Earth and

  16. Bags of words models of epitope sets: HIV viral load regression with counting grids.

    PubMed

    Perina, Alessandro; Lovato, Pietro; Jojic, Nebojsa

    2014-01-01

    The immune system gathers evidence of the execution of various molecular processes, both foreign and the cells' own, as time- and space-varying sets of epitopes, small linear or conformational segments of the proteins involved in these processes. Epitopes do not have any obvious ordering in this scheme: The immune system simply sees these epitope sets as disordered "bags" of simple signatures based on whose contents the actions need to be decided. The immense landscape of possible bags of epitopes is shaped by the cellular pathways in various cells, as well as the characteristics of the internal sampling process that chooses and brings epitopes to cellular surface. As a consequence, upon the infection by the same pathogen, different individuals' cells present very different epitope sets. Modeling this landscape should thus be a key step in computational immunology. We show that among possible bag-of-words models, the counting grid is most fit for modeling cellular presentation. We describe each patient by a bag-of-peptides they are likely to present on the cellular surface. In regression tests, we found that compared to the state-of-the-art, counting grids explain more than twice as much of the log viral load variance in these patients. This is potentially a significant advancement in the field, given that a large part of the log viral load variance also depends on the infecting HIV strain, and that HIV polymorphisms themselves are known to strongly associate with HLA types, both effects beyond what is modeled here.

  17. Variability of preference toward mechanical ventilator settings: a model-based behavioral analysis.

    PubMed

    Allerød, Charlotte; Karbing, Dan S; Thorgaard, Per; Andreassen, Steen; Kjærgaard, Søren; Rees, Stephen E

    2011-12-01

    The purpose of this study was to evaluate Danish clinicians' opinions toward ventilator settings using standardized model-simulated patients. The models ensured that all clinicians received identical presentations of data and anticipated responses to changes in patient state, enabling opinions on the same patient cases to be obtained from different clinicians. Ten Danish intensive care clinicians' and a computerized decision support system each provided suggestions for respiratory frequency (f), tidal volume (Vt) and insoired oxygen fraction (FiO2) in the same 10 model-simulated patient cases. The 110 suggestions were then evaluated by the 10 clinicians in a ranking and classification procedure. Clinicians' preferences toward ventilator settings (Fio(2), Vt, and f) and the resulting simulated values of arterial oxygen saturation, peak inspiratory pressure, and pH were significantly different (P < .005). The results of the classification showed that clinicians generally had poor opinion of the advice provided by other clinicians and the decision support system, considering this advice to be unacceptable in 33% of cases and good only in 21%. The ranking procedure also showed that clinicians did not agree on the best and worst advice. The present study shows significant difference in opinion on appropriate settings of f, Vt, and Fio(2) in the same computerized decision support system model-simulated patient cases. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Modeling bacterial colonization and infection routes in health care settings: analytic and numerical approaches.

    PubMed

    Simon, Carl P; Percha, Bethany; Riolo, Rick; Foxman, Betsy

    2013-10-07

    Health-care associated infections are a major problem in our society, accounting for tens of thousands of patient deaths and millions of dollars in wasted health care expenditures each year. Many of these infections are caused by bacteria that are transmitted from patient to patient either through direct contact or via the hands or clothing of health care workers. Because of the complexity of bacterial transmission routes in health care settings, computational approaches are essential, though often analytically intractable. Here we describe the construction and detailed analysis of a model for bacterial transmission in health care settings. Our model includes both colonization and disease stages for patients and health care workers, as well as an isolation ward and both patient-patient and patient-HCW-patient transmission pathways. We explicitly derive the basic reproductive ratio for this complex model, a nine-term expression that contains all nine ways with which a new colonization can occur. Using key parameters found in the medical literature, we use our model to gain insight into the relative importance of various bacterial transmission pathways within health care facilities, and to identify which forms of interventions are likely to prove most effective in hospitals and long-term care settings. We show that analytical and numerical approaches can complement each other as we seek to untangle the complex web of interactions that occur within a health care facility.

  19. SAF - Sets and Fields parallel I/O and scientific data modeling system

    SciTech Connect

    Matzke, Robb; Illescas, Eric; Espen, Peter; Jones, Jake S.; Sjaardema, Gregory; Miller, Mark C.; Schoof, Larry A.; Reus, James F.; Arrighi, William; Hitt, Ray T.; O'Brien, Matthew J.

    2005-07-01

    SAF is being developed as part of the Data Models and Formats (DMF) component of the Accelerated Strategic Computing Initiative (ASCI). SAF represents a revolutionary approach to interoperation of high performance, scientific computing applications based upon rigorous, math oriented data modeling principles. Previous technologies have required all applications to use the same data structures and/or mesh objects to represent scientific data or lead to an ever expanding set of incrementally different data structures and/or mesh objects. SAF addresses this problem by providing a small set of mathematical building blocks, sets, relations and fields, out of which a wide variety of scientific data can be characterized. Applications literally model their data by assembling these building blocks. Sets and fields building blocks are at once, both primitive and abstract: * They are primitive enough to model a wide variety of scientific data. * They are abstract enough to model the data in terms of what it represents in a mathematical or physical sense independent of how it is represented in an implementation sense. For example, while there are many ways to represent the airflow over the wing of a supersonic aircraft in a computer program, there is only one mathematical/physical interpretation: a field of 3D velocity vectors over a 2D surface. This latter description is immutable. It is independent of any particular representation or implementation choices. Understanding this what versus how relationship, that is what is represented versus how it is represented, is key to developing a solution for large scale integration of scientific software.

  20. Adjusting for Confounding in Early Postlaunch Settings: Going Beyond Logistic Regression Models.

    PubMed

    Schmidt, Amand F; Klungel, Olaf H; Groenwold, Rolf H H

    2016-01-01

    Postlaunch data on medical treatments can be analyzed to explore adverse events or relative effectiveness in real-life settings. These analyses are often complicated by the number of potential confounders and the possibility of model misspecification. We conducted a simulation study to compare the performance of logistic regression, propensity score, disease risk score, and stabilized inverse probability weighting methods to adjust for confounding. Model misspecification was induced in the independent derivation dataset. We evaluated performance using relative bias confidence interval coverage of the true effect, among other metrics. At low events per coefficient (1.0 and 0.5), the logistic regression estimates had a large relative bias (greater than -100%). Bias of the disease risk score estimates was at most 13.48% and 18.83%. For the propensity score model, this was 8.74% and >100%, respectively. At events per coefficient of 1.0 and 0.5, inverse probability weighting frequently failed or reduced to a crude regression, resulting in biases of -8.49% and 24.55%. Coverage of logistic regression estimates became less than the nominal level at events per coefficient ≤5. For the disease risk score, inverse probability weighting, and propensity score, coverage became less than nominal at events per coefficient ≤2.5, ≤1.0, and ≤1.0, respectively. Bias of misspecified disease risk score models was 16.55%. In settings with low events/exposed subjects per coefficient, disease risk score methods can be useful alternatives to logistic regression models, especially when propensity score models cannot be used. Despite better performance of disease risk score methods than logistic regression and propensity score models in small events per coefficient settings, bias, and coverage still deviated from nominal.

  1. A Model Plan for the Supervision and Evaluation of Therapy Services in Educational Settings. TIES: Therapy in Educational Settings.

    ERIC Educational Resources Information Center

    Reed, Penny; And Others

    The manual serves as a model for school districts developing procedures for supervising and evaluating their therapy services. The narrative is addressed to therapists rather than supervisors so that school districts can photocopy or adapt sections of the manual and assemble customized manuals for therapists in their programs. The first chapter,…

  2. Setting up a hydrological model based on global data for the Ayeyarwady basin in Myanmar

    NASA Astrophysics Data System (ADS)

    ten Velden, Corine; Sloff, Kees; Nauta, Tjitte

    2017-04-01

    The use of global datasets in local hydrological modelling can be of great value. It opens up the possibility to include data for areas where local data is not or only sparsely available. In hydrological modelling the existence of both static physical data such as elevation and land use, and dynamic meteorological data such as precipitation and temperature, is essential for setting up a hydrological model, but often such data is difficult to obtain at the local level. For the Ayeyarwady catchment in Myanmar a distributed hydrological model (Wflow: https://github.com/openstreams/wflow) was set up with only global datasets, as part of a water resources study. Myanmar is an emerging economy, which has only recently become more receptive to foreign influences. It has a very limited hydrometeorological measurement network, with large spatial and temporal gaps, and data that are of uncertain quality and difficult to obtain. The hydrological model was thus set up based on resampled versions of the SRTM digital elevation model, the GlobCover land cover dataset and the HWSD soil dataset. Three global meteorological datasets were assessed and compared for use in the hydrological model: TRMM, WFDEI and MSWEP. The meteorological datasets were assessed based on their conformity with several precipitation station measurements, and the overall model performance was assessed by calculating the NSE and RVE based on discharge measurements of several gauging stations. The model was run for the period 1979-2012 on a daily time step, and the results show an acceptable applicability of the used global datasets in the hydrological model. The WFDEI forcing dataset gave the best results, with a NSE of 0.55 at the outlet of the model and a RVE of 8.5%, calculated over the calibration period 2006-2012. As a general trend the modelled discharge at the upstream stations tends to be underestimated, and at the downstream stations slightly overestimated. The quality of the discharge measurements

  3. Software tools that facilitate kinetic modelling with large data sets: an example using growth modelling in sugarcane.

    PubMed

    Uys, L; Hofmeyr, J H S; Snoep, J L; Rohwer, J M

    2006-09-01

    A solution to manage cumbersome data sets associated with large modelling projects is described. A kinetic model of sucrose accumulation in sugarcane is used to predict changes in sucrose metabolism with sugarcane internode maturity. This results in large amounts of output data to be analysed. Growth is simulated by reassigning maximal activity values, specific to each internode of the sugarcane plant, to parameter attributes of a model object. From a programming perspective, only one model definition file is required for the simulation software used; however, the amount of input data increases with each extra interrnode that is modelled, and likewise the amount of output data that is generated also increases. To store, manipulate and analyse these data, the modelling was performed from within a spreadsheet. This was made possible by the scripting language Python and the modelling software PySCeS through an embedded Python interpreter available in the Gnumeric spreadsheet program.

  4. Recognition of Early Eocene global carbon isotope excursions using lipids of marine Thaumarchaeota

    NASA Astrophysics Data System (ADS)

    Schoon, Petra L.; Heilmann-Clausen, Claus; Pagh Schultz, Bo; Sluijs, Appy; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2013-07-01

    The Paleocene-Eocene Thermal Maximum (PETM; ˜56 Ma) and Eocene Thermal Maximum 2 (ETM2; ˜53 Ma) are geological short (<200,000 years) episodes of extreme global warming and environmental change. Both the PETM and ETM2 are associated with the injection of 13C-depleted carbon into the ocean-atmosphere system as revealed through a globally recognized carbon isotope excursion (CIE) and massive dissolution of deep sea carbonate. However, the magnitude of these CIEs vary with the type of fossil matter, i.e. multiple carbonate phases, bulk organic matter, and terrestrial and marine biomarker lipids, making it difficult to constrain the actual CIE in atmospheric and oceanic carbon pools. Here we analyzed the stable carbon isotopic composition (δ13C) of glycerol dibiphytanyl glycerol tetraether lipids (GDGTs) derived from marine Thaumarchaeota in sediments deposited during the PETM in the North Sea Basin and ETM2 in the Arctic Ocean. The δ13C values of these lipids are potentially directly recording variations in δ13C dissolved inorganic carbon (DIC) and can thus provide a record of marine δ13C DIC across both these Eocene carbon cycle perturbations. Reconstructed pre-CIE δ13CDIC values are slightly lower (0.5-1‰) than modern day values, possibly because Thaumarchaeotal lipids are not only derived from surface waters but also from 13C-depleted subsurface waters. Their values decrease by ˜3.6 (±0.3) ‰ and ˜2.5 (±0.7)‰ during the PETM and ETM2, respectively. The CIE in crenarchaeol for ETM2 is higher than that in marine calcite from other locations, possibly because of the admixture of deep water 13C-depleted CO2 generated by the euxinic conditions that developed occasionally during ETM2. However, the reconstructed PETM CIE lies close to the CIE inferred from marine calcite, suggesting that the δ13C record of crenarchaeol may document changes in marine DIC during the PETM in the North Sea Basin. The δ13C of thaumarchaeotal lipids may thus be a novel tool to

  5. Regionalisation of statistical model outputs creating gridded data sets for Germany

    NASA Astrophysics Data System (ADS)

    Höpp, Simona Andrea; Rauthe, Monika; Deutschländer, Thomas

    2016-04-01

    The goal of the German research program ReKliEs-De (regional climate projection ensembles for Germany, http://.reklies.hlug.de) is to distribute robust information about the range and the extremes of future climate for Germany and its neighbouring river catchment areas. This joint research project is supported by the German Federal Ministry of Education and Research (BMBF) and was initiated by the German Federal States. The Project results are meant to support the development of adaptation strategies to mitigate the impacts of future climate change. The aim of our part of the project is to adapt and transfer the regionalisation methods of the gridded hydrological data set (HYRAS) from daily station data to the station based statistical regional climate model output of WETTREG (regionalisation method based on weather patterns). The WETTREG model output covers the period of 1951 to 2100 with a daily temporal resolution. For this, we generate a gridded data set of the WETTREG output for precipitation, air temperature and relative humidity with a spatial resolution of 12.5 km x 12.5 km, which is common for regional climate models. Thus, this regionalisation allows comparing statistical to dynamical climate model outputs. The HYRAS data set was developed by the German Meteorological Service within the German research program KLIWAS (www.kliwas.de) and consists of daily gridded data for Germany and its neighbouring river catchment areas. It has a spatial resolution of 5 km x 5 km for the entire domain for the hydro-meteorological elements precipitation, air temperature and relative humidity and covers the period of 1951 to 2006. After conservative remapping the HYRAS data set is also convenient for the validation of climate models. The presentation will consist of two parts to present the actual state of the adaptation of the HYRAS regionalisation methods to the statistical regional climate model WETTREG: First, an overview of the HYRAS data set and the regionalisation

  6. Impact of CAMEX-4 Data Sets for Hurricane Forecasts using a Global Model

    NASA Technical Reports Server (NTRS)

    Kamineni, Rupa; Krishnamurti, T. N.; Pattnaik, S.; Browell, Edward V.; Ismail, Syed; Ferrare, Richard A.

    2005-01-01

    This study explores the impact on hurricane data assimilation and forecasts from the use of dropsondes and remote-sensed moisture profiles from the airborne Lidar Atmospheric Sensing Experiment (LASE) system. We show that the use of these additional data sets, above those from the conventional world weather watch, has a positive impact on hurricane predictions. The forecast tracks and intensity from the experiments show a marked improvement compared to the control experiment where such data sets were excluded. A study of the moisture budget in these hurricanes showed enhanced evaporation and precipitation over the storm area. This resulted in these data sets making a large impact on the estimate of mass convergence and moisture fluxes, which were much smaller in the control runs. Overall this study points to the importance of high vertical resolution humidity data sets for improved model results. We note that the forecast impact from the moisture profiling data sets for some of the storms is even larger than the impact from the use of dropwindsonde based winds.

  7. "no snow - no skiing excursion - consequences of climatic change?"

    NASA Astrophysics Data System (ADS)

    Neunzig, Thilo

    2014-05-01

    Climatology and climate change have become central topics in Geography at our school. Because of that we set up a climatological station at our school. The data are an important basis to observe sudden changes in the weather. The present winter (2013/2014) shows the importance of climate change in Alzey / Germany. In winter many students think of the yearly skiing trip to Schwaz / Austria which is part of our school programme. Due to that the following questions arise: Will skiing still be possible if climate change accelerates? How are the skiing regions in the Alpes going to change? What will happen in about 20 years? How does artificial snow change the landscape and the skiing sport? Students have to be aware of the ecological damage of skiing trips. Each class has to come up with a concept how these trips can be as environmentally friendly as possible. - the trip is for a restricted number of students only (year 8 only) - a small skiing region is chosen which is not overcrowded - snow has to be guaranteed in the ski area to avoid the production of artificial snow (avoidance of high water consumption) - the bus arrives with a class and returns with the one that had been there before These are but a few ideas of students in order to make their trip as environmentally friendly as possible. What is missing is only what is going to happen in the future. What will be the effect of climate change for skiing regions in the secondary mountains? How is the average temperature for winter going to develop? Are there possibilities for summer tourism (e.g. hiking) instead of skiing in winter? The students are going to try to find answers to these questions which are going to be presented on a poster on the GIFT-Workshop in Vienna.

  8. Phase field and level set methods for modeling solute precipitation and/or dissolution

    SciTech Connect

    Zhijie Xu; Hai Huang; Paul Meakin

    2012-01-01

    The dynamics of solid-liquid interfaces controlled by solute precipitation and/or dissolution due to the chemical reaction at the interface were computed in two dimensions using a phase field models. Sharp-interface asymptotic analysis demonstrated that the phase field solutions should converge to the proper sharp-interface precipitation/dissolution limit. For the purpose of comparison, the numerical solution of the sharp-interface model for solute precipitation/dissolution was directly solved using a level set method. In general, the phase field results are found in good agreement with the level set results for all reaction rates and geometry configurations investigated. Present study supports the applications of both methods to more complicated and realistic reactive systems, including the nuclear waste release and mineral precipitation and dissolution

  9. Phase field and level set methods for modeling solute precipitation and/or dissolution

    SciTech Connect

    Xu, Zhijie; Huang, Hai; Li, Xiaoyi; Meakin, Paul

    2012-01-02

    The dynamics of solid-liquid interfaces controlled by solute precipitation and/or dissolution due to the chemical reaction at the interface were computed in two dimensions using a phase field models. Sharp-interface asymptotic analysis demonstrated that the phase field solutions should converge to the proper sharp-interface precipitation/dissolution limit. For the purpose of comparison, the numerical solution of the sharp-interface model for solute precipitation/dissolution was directly solved using a level set method. In general, the phase field results are found in good agreement with the level set results for all reaction rates and geometry configurations. Present study supports the applications of both methods to more complicated and realistic reactive systems.

  10. Heuristic method for searches on large data-sets organised using network models

    NASA Astrophysics Data System (ADS)

    Ruiz-Fernández, D.; Quintana-Pacheco, Y.

    2016-05-01

    Searches on large data-sets have become an important issue in recent years. An alternative, which has achieved good results, is the use of methods relying on data mining techniques, such as cluster-based retrieval. This paper proposes a heuristic search that is based on an organisational model that reflects similarity relationships among data elements. The search is guided by using quality estimators of model nodes, which are obtained by the progressive evaluation of the given target function for the elements associated with each node. The results of the experiments confirm the effectiveness of the proposed algorithm. High-quality solutions are obtained evaluating a relatively small percentage of elements in the data-sets.

  11. Comparison of Computed SAR Focus-Setting Curves with Model Predictions

    DTIC Science & Technology

    1987-01-01

    optimal focus-setting velocity for azimuthally-traveling long surface waves occurs at one-half of the phase speed of the dominant wave . The computed...phase velocity or the orbital velocity of the wave . An important part of the paper involves the manner in which the data is analyzed Wc-&hew that...to obtain the optimally-focused image. One popular model favors the use of phase velocity of the long waves being imaged, while another favors the

  12. Analysis of Atmospheric Aerosol Data Sets and Application of Radiative Transfer Models to Compute Aerosol Effects

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Bergstrom, Robert W.; Redemann, Jens

    2002-01-01

    This report is the final report for "Analysis of Atmospheric Aerosol Data Sets and Application of Radiative Transfer Models to Compute Aerosol Effects". It is a bibliographic compilation of 29 peer-reviewed publications (published, in press or submitted) produced under this Cooperative Agreement and 30 first-authored conference presentations. The tasks outlined in the various proposals are listed below with a brief comment as to the research performed. Copies of title/abstract pages of peer-reviewed publications are attached.

  13. Recalibrating disease parameters for increasing realism in modeling epidemics in closed settings.

    PubMed

    Bioglio, Livio; Génois, Mathieu; Vestergaard, Christian L; Poletto, Chiara; Barrat, Alain; Colizza, Vittoria

    2016-11-14

    The homogeneous mixing assumption is widely adopted in epidemic modelling for its parsimony and represents the building block of more complex approaches, including very detailed agent-based models. The latter assume homogeneous mixing within schools, workplaces and households, mostly for the lack of detailed information on human contact behaviour within these settings. The recent data availability on high-resolution face-to-face interactions makes it now possible to assess the goodness of this simplified scheme in reproducing relevant aspects of the infection dynamics. We consider empirical contact networks gathered in different contexts, as well as synthetic data obtained through realistic models of contacts in structured populations. We perform stochastic spreading simulations on these contact networks and in populations of the same size under a homogeneous mixing hypothesis. We adjust the epidemiological parameters of the latter in order to fit the prevalence curve of the contact epidemic model. We quantify the agreement by comparing epidemic peak times, peak values, and epidemic sizes. Good approximations of the peak times and peak values are obtained with the homogeneous mixing approach, with a median relative difference smaller than 20 % in all cases investigated. Accuracy in reproducing the peak time depends on the setting under study, while for the peak value it is independent of the setting. Recalibration is found to be linear in the epidemic parameters used in the contact data simulations, showing changes across empirical settings but robustness across groups and population sizes. An adequate rescaling of the epidemiological parameters can yield a good agreement between the epidemic curves obtained with a real contact network and a homogeneous mixing approach in a population of the same size. The use of such recalibrated homogeneous mixing approximations would enhance the accuracy and realism of agent-based simulations and limit the intrinsic biases of

  14. Multiple data sets and modelling choices in a comparative LCA of disposable beverage cups.

    PubMed

    van der Harst, Eugenie; Potting, José; Kroeze, Carolien

    2014-10-01

    This study used multiple data sets and modelling choices in an environmental life cycle assessment (LCA) to compare typical disposable beverage cups made from polystyrene (PS), polylactic acid (PLA; bioplastic) and paper lined with bioplastic (biopaper). Incineration and recycling were considered as waste processing options, and for the PLA and biopaper cup also composting and anaerobic digestion. Multiple data sets and modelling choices were systematically used to calculate average results and the spread in results for each disposable cup in eleven impact categories. The LCA results of all combinations of data sets and modelling choices consistently identify three processes that dominate the environmental impact: (1) production of the cup's basic material (PS, PLA, biopaper), (2) cup manufacturing, and (3) waste processing. The large spread in results for impact categories strongly overlaps among the cups, however, and therefore does not allow a preference for one type of cup material. Comparison of the individual waste treatment options suggests some cautious preferences. The average waste treatment results indicate that recycling is the preferred option for PLA cups, followed by anaerobic digestion and incineration. Recycling is slightly preferred over incineration for the biopaper cups. There is no preferred waste treatment option for the PS cups. Taking into account the spread in waste treatment results for all cups, however, none of these preferences for waste processing options can be justified. The only exception is composting, which is least preferred for both PLA and biopaper cups. Our study illustrates that using multiple data sets and modelling choices can lead to considerable spread in LCA results. This makes comparing products more complex, but the outcomes more robust.

  15. Review and evaluation of performance measures for survival prediction models in external validation settings.

    PubMed

    Rahman, M Shafiqur; Ambler, Gareth; Choodari-Oskooei, Babak; Omar, Rumana Z

    2017-04-18

    When developing a prediction model for survival data it is essential to validate its performance in external validation settings using appropriate performance measures. Although a number of such measures have been proposed, there is only limited guidance regarding their use in the context of model validation. This paper reviewed and evaluated a wide range of performance measures to provide some guidelines for their use in practice. An extensive simulation study based on two clinical datasets was conducted to investigate the performance of the measures in external validation settings. Measures were selected from categories that assess the overall performance, discrimination and calibration of a survival prediction model. Some of these have been modified to allow their use with validation data, and a case study is provided to describe how these measures can be estimated in practice. The measures were evaluated with respect to their robustness to censoring and ease of interpretation. All measures are implemented, or are straightforward to implement, in statistical software. Most of the performance measures were reasonably robust to moderate levels of censoring. One exception was Harrell's concordance measure which tended to increase as censoring increased. We recommend that Uno's concordance measure is used to quantify concordance when there are moderate levels of censoring. Alternatively, Gönen and Heller's measure could be considered, especially if censoring is very high, but we suggest that the prediction model is re-calibrated first. We also recommend that Royston's D is routinely reported to assess discrimination since it has an appealing interpretation. The calibration slope is useful for both internal and external validation settings and recommended to report routinely. Our recommendation would be to use any of the predictive accuracy measures and provide the corresponding predictive accuracy curves. In addition, we recommend to investigate the characteristics

  16. Chemical Topic Modeling: Exploring Molecular Data Sets Using a Common Text-Mining Approach.

    PubMed

    Schneider, Nadine; Fechner, Nikolas; Landrum, Gregory A; Stiefl, Nikolaus

    2017-08-28

    Big data is one of the key transformative factors which increasingly influences all aspects of modern life. Although this transformation brings vast opportunities it also generates novel challenges, not the least of which is organizing and searching this data deluge. The field of medicinal chemistry is not different: more and more data are being generated, for instance, by technologies such as DNA encoded libraries, peptide libraries, text mining of large literature corpora, and new in silico enumeration methods. Handling those huge sets of molecules effectively is quite challenging and requires compromises that often come at the expense of the interpretability of the results. In order to find an intuitive and meaningful approach to organizing large molecular data sets, we adopted a probabilistic framework called "topic modeling" from the text-mining field. Here we present the first chemistry-related implementation of this method, which allows large molecule sets to be assigned to "chemical topics" and investigating the relationships between those. In this first study, we thoroughly evaluate this novel method in different experiments and discuss both its disadvantages and advantages. We show very promising results in reproducing human-assigned concepts using the approach to identify and retrieve chemical series from sets of molecules. We have also created an intuitive visualization of the chemical topics output by the algorithm. This is a huge benefit compared to other unsupervised machine-learning methods, like clustering, which are commonly used to group sets of molecules. Finally, we applied the new method to the 1.6 million molecules of the ChEMBL22 data set to test its robustness and efficiency. In about 1 h we built a 100-topic model of this large data set in which we could identify interesting topics like "proteins", "DNA", or "steroids". Along with this publication we provide our data sets and an open-source implementation of the new method (CheTo) which

  17. Agenda Setting for Health Promotion: Exploring an Adapted Model for the Social Media Era.

    PubMed

    Albalawi, Yousef; Sixsmith, Jane

    2015-01-01

    The foundation of best practice in health promotion is a robust theoretical base that informs design, implementation, and evaluation of interventions that promote the public's health. This study provides a novel contribution to health promotion through the adaptation of the agenda-setting approach in response to the contribution of social media. This exploration and proposed adaptation is derived from a study that examined the effectiveness of Twitter in influencing agenda setting among users in relation to road traffic accidents in Saudi Arabia. The proposed adaptations to the agenda-setting model to be explored reflect two levels of engagement: agenda setting within the social media sphere and the position of social media within classic agenda setting. This exploratory research aims to assess the veracity of the proposed adaptations on the basis of the hypotheses developed to test these two levels of engagement. To validate the hypotheses, we collected and analyzed data from two primary sources: Twitter activities and Saudi national newspapers. Keyword mentions served as indicators of agenda promotion; for Twitter, interactions were used to measure the process of agenda setting within the platform. The Twitter final dataset comprised 59,046 tweets and 38,066 users who contributed by tweeting, replying, or retweeting. Variables were collected for each tweet and user. In addition, 518 keyword mentions were recorded from six popular Saudi national newspapers. The results showed significant ratification of the study hypotheses at both levels of engagement that framed the proposed adaptions. The results indicate that social media facilitates the contribution of individuals in influencing agendas (individual users accounted for 76.29%, 67.79%, and 96.16% of retweet impressions, total impressions, and amplification multipliers, respectively), a component missing from traditional constructions of agenda-setting models. The influence of organizations on agenda setting is

  18. Agenda Setting for Health Promotion: Exploring an Adapted Model for the Social Media Era

    PubMed Central

    2015-01-01

    Background The foundation of best practice in health promotion is a robust theoretical base that informs design, implementation, and evaluation of interventions that promote the public’s health. This study provides a novel contribution to health promotion through the adaptation of the agenda-setting approach in response to the contribution of social media. This exploration and proposed adaptation is derived from a study that examined the effectiveness of Twitter in influencing agenda setting among users in relation to road traffic accidents in Saudi Arabia. Objective The proposed adaptations to the agenda-setting model to be explored reflect two levels of engagement: agenda setting within the social media sphere and the position of social media within classic agenda setting. This exploratory research aims to assess the veracity of the proposed adaptations on the basis of the hypotheses developed to test these two levels of engagement. Methods To validate the hypotheses, we collected and analyzed data from two primary sources: Twitter activities and Saudi national newspapers. Keyword mentions served as indicators of agenda promotion; for Twitter, interactions were used to measure the process of agenda setting within the platform. The Twitter final dataset comprised 59,046 tweets and 38,066 users who contributed by tweeting, replying, or retweeting. Variables were collected for each tweet and user. In addition, 518 keyword mentions were recorded from six popular Saudi national newspapers. Results The results showed significant ratification of the study hypotheses at both levels of engagement that framed the proposed adaptions. The results indicate that social media facilitates the contribution of individuals in influencing agendas (individual users accounted for 76.29%, 67.79%, and 96.16% of retweet impressions, total impressions, and amplification multipliers, respectively), a component missing from traditional constructions of agenda-setting models. The influence

  19. Testing and Application in Mission Critical Settings and Transmission, Siting, and Metrics Models Research

    SciTech Connect

    Rich Sedano-Regulatory Assistance Project; Mariana Uhrlaub

    2006-10-31

    The Distributed Generation: Testing and Application in Mission Critical Settings and Transmission, Siting, and Metrics Models Research grant has been in place for several years and has accomplished all the objectives and deliverables that were originally set forth in the proposal. The National Association of State Energy Officials (NASEO), the City of Portland, OR, Bureau of Environmental Services and the Regulatory Assistance Project (RAP) have been able to successfully monitor and evaluate DG applications in a wastewater treatment plant environment, develop a metrics model for new voluntary DG guidelines that could be used as a prototype, and through outreach and education venues provide the results of these projects to state, professional, and national organizations and their members addressing similar issues. This project had three specific tasks associated with it: (1) Field Research and Testing; (2) Metrics/Verification Model for DG Guidelines; and (3) Northeastern Transmission/Siting Data Research. Each task had its own set of challenges and lessons learned but overall there were many successes that will serve as learning opportunities in these technology areas. Continuing to share the outcomes of this project with a wider audience will be beneficial for all those involved in distributed generation and combined heat and power projects.

  20. Northern Russian chironomid-based modern summer temperature data set and inference models

    NASA Astrophysics Data System (ADS)

    Nazarova, Larisa; Self, Angela E.; Brooks, Stephen J.; van Hardenbroek, Maarten; Herzschuh, Ulrike; Diekmann, Bernhard

    2015-11-01

    West and East Siberian data sets and 55 new sites were merged based on the high taxonomic similarity, and the strong relationship between mean July air temperature and the distribution of chironomid taxa in both data sets compared with other environmental parameters. Multivariate statistical analysis of chironomid and environmental data from the combined data set consisting of 268 lakes, located in northern Russia, suggests that mean July air temperature explains the greatest amount of variance in chironomid distribution compared with other measured variables (latitude, longitude, altitude, water depth, lake surface area, pH, conductivity, mean January air temperature, mean July air temperature, and continentality). We established two robust inference models to reconstruct mean summer air temperatures from subfossil chironomids based on ecological and geographical approaches. The North Russian 2-component WA-PLS model (RMSEPJack = 1.35 °C, rJack2 = 0.87) can be recommended for application in palaeoclimatic studies in northern Russia. Based on distinctive chironomid fauna and climatic regimes of Kamchatka the Far East 2-component WAPLS model (RMSEPJack = 1.3 °C, rJack2 = 0.81) has potentially better applicability in Kamchatka.

  1. Musculoskeletal Simulation Model Generation from MRI Data Sets and Motion Capture Data

    NASA Astrophysics Data System (ADS)

    Schmid, Jérôme; Sandholm, Anders; Chung, François; Thalmann, Daniel; Delingette, Hervé; Magnenat-Thalmann, Nadia

    Today computer models and computer simulations of the musculoskeletal system are widely used to study the mechanisms behind human gait and its disorders. The common way of creating musculoskeletal models is to use a generic musculoskeletal model based on data derived from anatomical and biomechanical studies of cadaverous specimens. To adapt this generic model to a specific subject, the usual approach is to scale it. This scaling has been reported to introduce several errors because it does not always account for subject-specific anatomical differences. As a result, a novel semi-automatic workflow is proposed that creates subject-specific musculoskeletal models from magnetic resonance imaging (MRI) data sets and motion capture data. Based on subject-specific medical data and a model-based automatic segmentation approach, an accurate modeling of the anatomy can be produced while avoiding the scaling operation. This anatomical model coupled with motion capture data, joint kinematics information, and muscle-tendon actuators is finally used to create a subject-specific musculoskeletal model.

  2. Plane surface suddenly set in motion in a viscoelastic fluid with fractional Maxwell model

    NASA Astrophysics Data System (ADS)

    Wenchang, Tan; Mingyu, Xu

    2002-08-01

    The fractional calculus approach in the constitutive relationship model of viscoelastic fluid is introduced. The flow near a wall suddenly set in motion is studied for a non-Newtonian viscoelastic fluid with the fractional Maxwell model. Exact solutions of velocity and stress are obtained by using the discrete inverse Laplace transform of the sequential fractional derivatives. It is found that the effect of the fractional orders in the constitutive relationship on the flow field is significant. The results show that for small times there are appreciable viscoelastic effects on the shear stress at the plate, for large times the viscoelastic effects become weak.

  3. A long-term data set for hydrologic modeling in a snow-dominated mountain catchment

    NASA Astrophysics Data System (ADS)

    Reba, Michele L.; Marks, Danny; Seyfried, Mark; Winstral, Adam; Kumar, Mukesh; Flerchinger, Gerald

    2011-07-01

    A modeling data set (meteorological forcing data, geographic information system data, and validation data) is presented for water years 1984 through 2008 for a snow-dominated mountain catchment. The forcing data include hourly precipitation, wind speed and direction, air and soil temperature, relative humidity, dew point temperature, and incoming solar and thermal radiation from two sites. Validation data include stream discharge, snow water equivalent, snow depth, soil moisture, and groundwater elevation. These data will improve the development, testing, and application of the next generation of hydrologic models.

  4. On the first-excursion probability in stationary narrow-band random vibration. II.

    NASA Technical Reports Server (NTRS)

    Yang, J.-N.; Shinozuka, M.

    1972-01-01

    The first-excursion probability of a stationary narrow-band Gaussian process with mean zero has been studied. Within the framework of point process approach, series approximations derived from the theory of random points and approximations based on the maximum entropy principle have been developed. With the aid of numerical examples, merits of the approximations proposed previously as well as of those developed in this paper have been compared. The results indicate that the maximum entropy principle has not produced satisfactory approximations but the approximation based on nonapproaching random points is found to be the best among all the approximations proposed herein. A conclusion drawn from the present and the previous studies is that the point process approach produces a number of useful approximations for the first-excursion probability, particularly those based on the concepts of the Markov process, the clump-size, and the nonapproaching random points.

  5. Mono Lake Excursion as a Chronologic Marker in the U.S. Great Basin

    NASA Astrophysics Data System (ADS)

    Liddicoat, J. C.; Coe, R. S.; Knott, J. R.

    2008-05-01

    Nevada, Utah, and California east of the Sierra Nevada are in the Great Basin physiographic province of western North America. During periods of the Pleistocene, Lake Bonneville and Lake Lahontan covered valleys in Utah and Nevada, respectively, and other lakes such as Lake Russell in east-central California did likewise (Feth, 1964). Now dry except for its remnant, Mono Lake, Lake Russell provides an opportunity to study behavior of Earth's past magnetic field in lacustrine sediments that are exposed in natural outcrops. The sediments record at least 30,000 years of paleomagnetic secular variation (Liddicoat, 1976; Zimmerman et al., 2006) and have been of particular interest since the discovery of the Mono Lake Excursion (MLE) by Denham and Cox (1971) because the field behavior can be documented at numerous sites around Mono Lake (Liddicoat and Coe, 1979, Liddicoat, 1992; Coe and Liddicoat, 1994) and on Paoha Island in the lake. Moreover, there have been recent attempts to date the excursion (Kent et al., 2002, Benson et al., 2003) more accurately and use the age and relative field intensity in paleoclimate research (Zimmerman et al., 2006). It has been proposed that the excursion in the Mono Basin might be older than originally believed (Denham and Cox, 1971; Liddicoat and Coe, 1979) and instead be the Laschamp Excursion (LE), ~ 40,000 yrs B.P. (Guillou et al., 2004), on the basis of 14C and 40Ar/39Ar dates (Kent et al., 2002) and the relative paleointensity record (Zimmerman et al., 2006) for the excursion in the Mono Basin. On the contrary, we favor a younger age for the excursion, ~ 32,000 yrs B.P., using the relative paleointensity at the Mono and Lahontan basins and 14C dates from the Lahontan Basin (Benson et al., 2003). The age of ~ 32,000 yrs B.P. is in accord with the age (32,000-34,000 yrs B.P.) reported by Channell (2006) for the MLE at Ocean Drilling Program (ODP) Site 919 in the Irminger Basin in the North Atlantic Ocean, which contains as well an

  6. Data, models, and views: towards integration of diverse numerical model components and data sets for scientific and public dissemination

    NASA Astrophysics Data System (ADS)

    Hofmeister, Richard; Lemmen, Carsten; Nasermoaddeli, Hassan; Klingbeil, Knut; Wirtz, Kai

    2015-04-01

    Data and models for describing coastal systems span a diversity of disciplines, communities, ecosystems, regions and techniques. Previous attempts of unifying data exchange, coupling interfaces, or metadata information have not been successful. We introduce the new Modular System for Shelves and Coasts (MOSSCO, http://www.mossco.de), a novel coupling framework that enables the integration of a diverse array of models and data from different disciplines relating to coastal research. In the MOSSCO concept, the integrating framework imposes very few restrictions on contributed data or models; in fact, there is no distinction made between data and models. The few requirements are: (1) principle coupleability, i.e. access to I/O and timing information in submodels, which has recently been referred to as the Basic Model Interface (BMI) (2) open source/open data access and licencing and (3) communication of metadata, such as spatiotemporal information, naming conventions, and physical units. These requirements suffice to integrate different models and data sets into the MOSSCO infrastructure and subsequently built a modular integrated modeling tool that can span a diversity of processes and domains. We demonstrate how diverse coastal system constituents were integrated into this modular framework and how we deal with the diverging development of constituent data sets and models at external institutions. Finally, we show results from simulations with the fully coupled system using OGC WebServices in the WiMo geoportal (http://kofserver3.hzg.de/wimo), from where stakeholders can view the simulation results for further dissemination.

  7. From data to the decision: A software architecture to integrate predictive modelling in clinical settings.

    PubMed

    Martinez-Millana, A; Fernandez-Llatas, C; Sacchi, L; Segagni, D; Guillen, S; Bellazzi, R; Traver, V

    2015-08-01

    The application of statistics and mathematics over large amounts of data is providing healthcare systems with new tools for screening and managing multiple diseases. Nonetheless, these tools have many technical and clinical limitations as they are based on datasets with concrete characteristics. This proposition paper describes a novel architecture focused on providing a validation framework for discrimination and prediction models in the screening of Type 2 diabetes. For that, the architecture has been designed to gather different data sources under a common data structure and, furthermore, to be controlled by a centralized component (Orchestrator) in charge of directing the interaction flows among data sources, models and graphical user interfaces. This innovative approach aims to overcome the data-dependency of the models by providing a validation framework for the models as they are used within clinical settings.

  8. Designing an activity-based costing model for a non-admitted prisoner healthcare setting.

    PubMed

    Cai, Xiao; Moore, Elizabeth; McNamara, Martin

    2013-09-01

    To design and deliver an activity-based costing model within a non-admitted prisoner healthcare setting. Key phases from the NSW Health clinical redesign methodology were utilised: diagnostic, solution design and implementation. The diagnostic phase utilised a range of strategies to identify issues requiring attention in the development of the costing model. The solution design phase conceptualised distinct 'building blocks' of activity and cost based on the speciality of clinicians providing care. These building blocks enabled the classification of activity and comparisons of costs between similar facilities. The implementation phase validated the model. The project generated an activity-based costing model based on actual activity performed, gained acceptability among clinicians and managers, and provided the basis for ongoing efficiency and benchmarking efforts.

  9. Using climate models to estimate the quality of global observational data sets.

    PubMed

    Massonnet, François; Bellprat, Omar; Guemas, Virginie; Doblas-Reyes, Francisco J

    2016-10-28

    Observational estimates of the climate system are essential to monitoring and understanding ongoing climate change and to assessing the quality of climate models used to produce near- and long-term climate information. This study poses the dual and unconventional question: Can climate models be used to assess the quality of observational references? We show that this question not only rests on solid theoretical grounds but also offers insightful applications in practice. By comparing four observational products of sea surface temperature with a large multimodel climate forecast ensemble, we find compelling evidence that models systematically score better against the most recent, advanced, but also most independent product. These results call for generalized procedures of model-observation comparison and provide guidance for a more objective observational data set selection. Copyright © 2016, American Association for the Advancement of Science.

  10. A connectionist model for convex-hull of a planar set.

    PubMed

    Datta, A; Pal, S; Pal, N R

    2000-04-01

    A neural network model is proposed for computation of the convex-hull of a finite planar set. The model is self-organizing in that it adapts itself to the hull-vertices of the convex-hull in an orderly fashion without any supervision. The proposed network consists of three layers of processors. The bottom layer computes the activation functions, the outputs of which are passed onto the middle layer. The middle layer is used for winner selection. These information are passed onto the topmost layer as well as fed back to the bottom layer. The network in the topmost layer self-organizes by labeling the hull-processors in an orderly fashion so that the final convex-hull is obtained from the topmost layer. Time complexities of the proposed model are analyzed and are compared with existing models of similar nature.

  11. Using climate models to estimate the quality of global observational data sets

    NASA Astrophysics Data System (ADS)

    Massonnet, François; Bellprat, Omar; Guemas, Virginie; Doblas-Reyes, Francisco J.

    2016-10-01

    Observational estimates of the climate system are essential to monitoring and understanding ongoing climate change and to assessing the quality of climate models used to produce near- and long-term climate information. This study poses the dual and unconventional question: Can climate models be used to assess the quality of observational references? We show that this question not only rests on solid theoretical grounds but also offers insightful applications in practice. By comparing four observational products of sea surface temperature with a large multimodel climate forecast ensemble, we find compelling evidence that models systematically score better against the most recent, advanced, but also most independent product. These results call for generalized procedures of model-observation comparison and provide guidance for a more objective observational data set selection.

  12. Modified graphical autocatalytic set model of combustion process in circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Yusof, Nurul Syazwani; Bakar, Sumarni Abu; Ismail, Razidah

    2014-07-01

    Circulating Fluidized Bed Boiler (CFB) is a device for generating steam by burning fossil fuels in a furnace operating under a special hydrodynamic condition. Autocatalytic Set has provided a graphical model of chemical reactions that occurred during combustion process in CFB. Eight important chemical substances known as species were represented as nodes and catalytic relationships between nodes are represented by the edges in the graph. In this paper, the model is extended and modified by considering other relevant chemical reactions that also exist during the process. Catalytic relationship among the species in the model is discussed. The result reveals that the modified model is able to gives more explanation of the relationship among the species during the process at initial time t.

  13. Decreased diaphragm excursion in stroke patients with dysphagia as assessed by M-mode sonography.

    PubMed

    Park, Geun-Young; Kim, Seong-Rim; Kim, Young Woo; Jo, Kwang Wook; Lee, Eu Jeen; Kim, Young Moon; Im, Sun

    2015-01-01

    To record diaphragm excursion via M-mode ultrasonography in stroke patients with dysphagia and determine whether they present reduced diaphragm excursion during voluntary cough compared with stroke patients without dysphagia and healthy subjects. Prospective cross-sectional study. University rehabilitation hospital. Acute stroke patients with dysphagia (n=23), acute stroke patients without dysphagia (n=24), and healthy control participants (n=27) (N=74). Not applicable. Diaphragm motions during quiet breathing, deep breathing, and voluntary coughing were recorded via ultrasonography using M-mode tracing (mm). Maximum inspiratory and expiratory pressures (cmH2O) and peak cough flow (L/min) during voluntary coughing were measured. The mean diaphragm movement (mm) of the hemiplegic side for all groups during quiet breathing, deep breathing, and voluntary coughing was 14.8±4.3, 17.6±4.8, and 20.9±3.7 (P<.001); 23.8±7.1, 32.7±10.6, and 44.7±10.3 (P<.001); and 16.8±4.8, 28.5±4.9, and 36.0±8.2 (P<.001), respectively. The differences were statistically significant. Differences were observed in the maximum inspiratory (P<.001) and expiratory (P<.001) pressures and peak cough flow (P=.027) among the 3 groups. Forward selection stepwise regression analysis, which was performed to determine variables that help predict diaphragm excursion during voluntary coughing, showed that the presence of dysphagia explained up to 60% (P<.001) of the hemiplegic diaphragm movement during voluntary coughing in patients with stroke. M-mode ultrasonography showed that stroke patients with dysphagia have decreased diaphragm excursion and compromised respiratory function during voluntary coughing. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  14. Cerium anomaly across the mid-Tournaisian carbon isotope excursion (TICE)

    NASA Astrophysics Data System (ADS)

    Jiang, G.; Morales, D. C.; Maharjan, D. K.

    2015-12-01

    The Early Mississippian (ca. 359-345 Ma) represents one of the most important greenhouse-icehouse climate transitions in Earth history. Closely associated with this critical transition is a prominent positive carbon isotope excursion (δ13C ≥ +5‰) that has been documented from numerous stratigraphic successions across the globe. This δ13C excursion, informally referred to as the TICE (mid-Tournaisian carbon isotope excursion) event, has been interpreted as resulting from enhanced organic carbon burial, with anticipated outcomes including the lowering of atmospheric CO2 and global cooling, the growth of continental ice sheets and sea-level fall, and the increase of ocean oxygenation and ocean redox changes. The casual relationship between these events has been addressed from various perspectives but not yet clearly demonstrated. To document the potential redox change associated with the perturbation of the carbon cycle, we have analyzed rare earth elements (REE) and trace elements across the TICE in two sections across a shallow-to-deep water transect in the southern Great Basin (Utah and Nevada), USA. In both sections, the REE data show a significant positive cerium (Ce) anomaly (Ce/Ce* = Ce/(0.5La+0.5Pr)). Prior to the positive δ13C shift, most Ce/Ce* values are around 0.3 (between 0.2 and 0.4). Across the δ13C peak, Ce/Ce* values increase up to 0.87, followed by a decrease back to 0.2~0.3 after the δ13C excursion (Figure 1). The positive Ce anomaly is best interpreted as recording expansion of oxygen minimum zone and anoxia resulted from increased primary production. This is consistent with a significant increase of nitrogen isotopes (δ15N) across the δ13C peak. Integration of the carbon, nitrogen, and REE data demonstrates a responsive earth systems change linked to the perturbation of the Early Mississippian carbon cycle.

  15. Boron and diagenesis: Questioning the fidelity of Snowball δ11B excursions

    NASA Astrophysics Data System (ADS)

    Foster, G. L.; Stewart, J.; Gutjahr, M.; Pearce, F.; Swart, P. K.

    2014-12-01

    Large negative carbon (δ13C) and boron (δ11B) isotope excursions (both >6‰) within the widely distributed Neoproterozoic "Snowball Earth" cap carbonates are interpreted as evidence for considerable perturbation of the carbon cycle and the associated reduction, then recovery of global ocean pH. Yet, before conclusive interpretations may be drawn, isotopic data must first be shown to be primary in origin and non-diagenetic. Recent studies of Quaternary carbonate platform sediments from a number of locations worldwide reveal δ13C excursions of similar magnitude and distribution to the "Snowball Earth" excursions. However, these recent analogues were formed following eustatic sea level fall and exposure of recent carbonates to meteoric diagenesis (Swart and Kennedy, 2012). Here we present δ11B and B/Ca data from Pleistocene-aged carbonate platform sediments recovered by the Clino Core from the Bahamas to examine the effects of diagenesis on the boron system. We find that within the interval of meteoric diagenesis the δ11B of bulk carbonate is substantially reduced by approximately 6‰ in conjunction with a drop in B/Ca of 90%. These isotopic and elemental down-core patterns are strikingly similar to those reported for δ11B and B/Ca in the cap carbonates of the Neoproterozoic snowball Earth events (Kasemann et al., 2005; Kasemann et al., 2010). Our results may therefore question the primary nature of "Snowball Earth" isotope excursions. We recommend more rigorous assessment of the diagenetic history of these ancient carbonates to ensure palaeoclimatological interpretations are robust.

  16. Effects of temperature excursions on mean kinetic temperature and shelf life.

    PubMed

    Kommanaboyina, B; Rhodes, C T

    1999-12-01

    The international acceptance of the definition of controlled room temperature (CRT) has given additional impetus to the use of mean kinetic temperature (MKT) as a method of quantifying temperatures during transport and storage and consequent possible effects on drug product stability. The present paper explores some of the implications of the MKT concept and considers the effect of temperature excursions on MKT values and hence on stability of drug products.

  17. Terminator field-aligned current system: A new finding from model-assimilated data set (MADS)

    NASA Astrophysics Data System (ADS)

    Zhu, L.; Schunk, R. W.; Scherliess, L.; Sojka, J. J.; Gardner, L. C.; Eccles, J. V.; Rice, D.

    2013-12-01

    Physics-based data assimilation models have been recognized by the space science community as the most accurate approach to specify and forecast the space weather of the solar-terrestrial environment. The model-assimilated data sets (MADS) produced by these models constitute an internally consistent time series of global three-dimensional fields whose accuracy can be estimated. Because of its internal consistency of physics and completeness of descriptions on the status of global systems, the MADS has also been a powerful tool to identify the systematic errors in measurements, reveal the missing physics in physical models, and discover the important dynamical physical processes that are inadequately observed or missed by measurements due to observational limitations. In the past years, we developed a data assimilation model for the high-latitude ionospheric plasma dynamics and electrodynamics. With a set of physical models, an ensemble Kalman filter, and the ingestion of data from multiple observations, the data assimilation model can produce a self-consistent time-series of the complete descriptions of the global high-latitude ionosphere, which includes the convection electric field, horizontal and field-aligned currents, conductivity, as well as 3-D plasma densities and temperatures, In this presentation, we will show a new field-aligned current system discovered from the analysis of the MADS produced by our data assimilation model. This new current system appears and develops near the ionospheric terminator. The dynamical features of this current system will be described and its connection to the active role of the ionosphere in the M-I coupling will be discussed.

  18. Effect of flow leakage on the benchmarking of FLOWTRAN with Mark-22 mockup flow excursion test data from Babcock and Wilcox

    SciTech Connect

    Chen, Kuo-Fu.

    1992-10-01

    This report presents a revised analysis of the Babcock and Wilcox (B and W) downflow flow excursion tests that accounts for leakage between flow channels in the test assembly. Leak rates were estimated by comparing results from the downflow tests with those for upflow tests conducted using an identical assembly with some minor modifications. The upflow test assembly did not contain leaks. This revised analyses shows that FLOWTRAN with the SRS working criterion conservatively predicts onset of flow instability without using a local peaking factor to model heat transfer variations near the ribs.

  19. Iron in galaxy groups and clusters: confronting galaxy evolution models with a newly homogenized data set

    NASA Astrophysics Data System (ADS)

    Yates, Robert M.; Thomas, Peter A.; Henriques, Bruno M. B.

    2017-01-01

    We present an analysis of the iron abundance in the hot gas surrounding galaxy groups and clusters. To do this, we first compile and homogenize a large data set of 79 low-redshift (tilde{z} = 0.03) systems (159 individual measurements) from the literature. Our analysis accounts for differences in aperture size, solar abundance, and cosmology, and scales all measurements using customized radial profiles for the temperature (T), gas density (ρgas), and iron abundance (ZFe). We then compare this data set to groups and clusters in the L-GALAXIES galaxy evolution model. Our homogenized data set reveals a tight T-ZFe relation for clusters, with a scatter in ZFe of only 0.10 dex and a slight negative gradient. After examining potential measurement biases, we conclude that some of this negative gradient has a physical origin. Our model suggests greater accretion of hydrogen in the hottest systems, via stripping from infalling satellites, as a cause. In groups, L-GALAXIES over-estimates ZFe, indicating that metal-rich gas removal (via e.g. AGN feedback) is required. L-GALAXIES is consistent with the observed ZFe in the intracluster medium (ICM) of the hottest clusters at z = 0, and shows a similar rate of ICM enrichment as that observed from at least z ˜ 1.3 to the present day. This is achieved without needing to modify any of the galactic chemical evolution (GCE) model parameters. However, the ZFe in intermediate-T clusters could be under-estimated in our model. We caution that modifications to the GCE modelling to correct this disrupt the agreement with observations of galaxies' stellar components.

  20. The Laschamp geomagnetic excursion featured in nitrate record from EPICA-Dome C ice core

    PubMed Central

    Traversi, R.; Becagli, S.; Poluianov, S.; Severi, M.; Solanki, S. K.; Usoskin, I. G.; Udisti, R.

    2016-01-01

    Here we present the first direct comparison of cosmogenic 10Be and chemical species in the period of 38–45.5 kyr BP spanning the Laschamp geomagnetic excursion from the EPICA-Dome C ice core. A principal component analysis (PCA) allowed to group different components as a function of the main sources, transport and deposition processes affecting the atmospheric aerosol at Dome C. Moreover, a wavelet analysis highlighted the high coherence and in-phase relationship between 10Be and nitrate at this time. The evident preferential association of 10Be with nitrate rather than with other chemical species was ascribed to the presence of a distinct source, here labelled as “cosmogenic”. Both the PCA and wavelet analyses ruled out a significant role of calcium in driving the 10Be and nitrate relationship, which is particularly relevant for a plateau site such as Dome C, especially in the glacial period during which the Laschamp excursion took place. The evidence that the nitrate record from the EDC ice core is able to capture the Laschamp event hints toward the possibility of using this marker for studying galactic cosmic ray flux variations and thus also major geomagnetic field excursions at pluri-centennial-millennial time scales, thus opening up new perspectives in paleoclimatic studies. PMID:26819064

  1. Effect of lateral excursive movements on the progression of abfraction lesions.

    PubMed

    Wood, Ian David; Kassir, Ali Sabet Abbas; Brunton, Paul Anthony

    2009-01-01

    The theory of abfraction suggests that tooth flexure arising from occlusal loads causes the formation and progression of abfraction lesions. The current study investigated whether reducing occlusal loading by adjusting the occlusion on a tooth during lateral excursive movements had any effect on the rate of progression of existing abfraction lesions. Recruited were 39 subjects who had two non-carious cervical lesions in the maxillary arch that did not need restoration and were in group function during lateral excursive movements of the mandible. One of the teeth was randomly selected to have the excursive occlusal contacts reduced by using a fine grain diamond bur. Centric occlusal contacts were not reduced. Impressions of the lesion were taken over a 30-month period to enable monitoring of the wear rate, and duplicate dies were poured into epoxy resin to allow for sectioning. The size of the lesions was measured using stereomicroscopic analysis of the sectioned epoxy resin dies, and the results were analyzed using an Independent t-test. No statistically significant difference in wear rates between the adjusted and non-adjusted teeth was found (p > 0.05). Within the limitations of the current study, it was concluded that occlusal adjustment does not appear to halt the progression of non-carious cervical lesions; consequently, this procedure cannot be recommended.

  2. Comparison of Dynamic Balance in Collegiate Field Hockey and Football Players Using Star Excursion Balance Test

    PubMed Central

    Bhat, Rashi; Moiz, Jamal Ali

    2013-01-01

    Purpose The preliminary study aimed to compare dynamic balance between collegiate athletes competing or training in football and hockey using star excursion balance test. Methods A total thirty university level players, football (n = 15) and field hockey (n = 15) were participated in the study. Dynamic balance was assessed by using star excursion balance test. The testing grid consists of 8 lines each 120 cm in length extending from a common point at 45° increments. The subjects were instructed to maintain a stable single leg stance with the test leg with shoes off and to reach for maximal distance with the other leg in each of the 8 directions. A pencil was used to point and read the distance to which each subject's foot reached. The normalized leg reach distances in each direction were summed for both limbs and the total sum of the mean of summed normalized distances of both limbs were calculated. Results There was no significant difference in all the directions of star excursion balance test scores in both the groups. Additionally, composite reach distances of both groups also found non-significant (P=0.5). However, the posterior (P=0.05) and lateral (P=0.03) normalized reach distances were significantly more in field hockey players. Conclusion Field hockey players and football players did not differ in terms of dynamic balance. PMID:24427482

  3. Independent validation of the modified prognosis palliative care study predictor models in three palliative care settings.

    PubMed

    Baba, Mika; Maeda, Isseki; Morita, Tatsuya; Hisanaga, Takayuki; Ishihara, Tatsuhiko; Iwashita, Tomoyuki; Kaneishi, Keisuke; Kawagoe, Shohei; Kuriyama, Toshiyuki; Maeda, Takashi; Mori, Ichiro; Nakajima, Nobuhisa; Nishi, Tomohiro; Sakurai, Hiroki; Shimoyama, Satofumi; Shinjo, Takuya; Shirayama, Hiroto; Yamada, Takeshi; Ono, Shigeki; Ozawa, Taketoshi; Yamamoto, Ryo; Tsuneto, Satoru

    2015-05-01

    Accurate prognostic information in palliative care settings is needed for patients to make decisions and set goals and priorities. The Prognosis Palliative Care Study (PiPS) predictor models were presented in 2011, but have not yet been fully validated by other research teams. The primary aim of this study is to examine the accuracy and to validate the modified PiPS (using physician-proxy ratings of mental status instead of patient interviews) in three palliative care settings, namely palliative care units, hospital-based palliative care teams, and home-based palliative care services. This multicenter prospective cohort study was conducted in 58 palliative care services including 16 palliative care units, 19 hospital-based palliative care teams, and 23 home-based palliative care services in Japan from September 2012 through April 2014. A total of 2426 subjects were recruited. For reasons including lack of followup and missing variables (primarily blood examination data), we obtained analyzable data from 2212 and 1257 patients for the modified PiPS-A and PiPS-B, respectively. In all palliative care settings, both the modified PiPS-A and PiPS-B identified three risk groups with different survival rates (P<0.001). The absolute agreement ranged from 56% to 60% in the PiPS-A model and 60% to 62% in the PiPS-B model. The modified PiPS was successfully validated and can be useful in palliative care units, hospital-based palliative care teams, and home-based palliative care services. Copyright © 2015 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  4. H2RM: A Hybrid Rough Set Reasoning Model for Prediction and Management of Diabetes Mellitus.

    PubMed

    Ali, Rahman; Hussain, Jamil; Siddiqi, Muhammad Hameed; Hussain, Maqbool; Lee, Sungyoung

    2015-07-03

    Diabetes is a chronic disease characterized by high blood glucose level that results either from a deficiency of insulin produced by the body, or the body's resistance to the effects of insulin. Accurate and precise reasoning and prediction models greatly help physicians to improve diagnosis, prognosis and treatment procedures of different diseases. Though numerous models have been proposed to solve issues of diagnosis and management of diabetes, they have the following drawbacks: (1) restricted one type of diabetes; (2) lack understandability and explanatory power of the techniques and decision; (3) limited either to prediction purpose or management over the structured contents; and (4) lack competence for dimensionality and vagueness of patient's data. To overcome these issues, this paper proposes a novel hybrid rough set reasoning model (H2RM) that resolves problems of inaccurate prediction and management of type-1 diabetes mellitus (T1DM) and type-2 diabetes mellitus (T2DM). For verification of the proposed model, experimental data from fifty patients, acquired from a local hospital in semi-structured format, is used. First, the data is transformed into structured format and then used for mining prediction rules. Rough set theory (RST) based techniques and algorithms are used to mine the prediction rules. During the online execution phase of the model, these rules are used to predict T1DM and T2DM for new patients. Furthermore, the proposed model assists physicians to manage diabetes using knowledge extracted from online diabetes guidelines. Correlation-based trend analysis techniques are used to manage diabetic observations. Experimental results demonstrate that the proposed model outperforms the existing methods with 95.9% average and balanced accuracies.

  5. H2RM: A Hybrid Rough Set Reasoning Model for Prediction and Management of Diabetes Mellitus

    PubMed Central

    Ali, Rahman; Hussain, Jamil; Siddiqi, Muhammad Hameed; Hussain, Maqbool; Lee, Sungyoung

    2015-01-01

    Diabetes is a chronic disease characterized by high blood glucose level that results either from a deficiency of insulin produced by the body, or the body’s resistance to the effects of insulin. Accurate and precise reasoning and prediction models greatly help physicians to improve diagnosis, prognosis and treatment procedures of different diseases. Though numerous models have been proposed to solve issues of diagnosis and management of diabetes, they have the following drawbacks: (1) restricted one type of diabetes; (2) lack understandability and explanatory power of the techniques and decision; (3) limited either to prediction purpose or management over the structured contents; and (4) lack competence for dimensionality and vagueness of patient’s data. To overcome these issues, this paper proposes a novel hybrid rough set reasoning model (H2RM) that resolves problems of inaccurate prediction and management of type-1 diabetes mellitus (T1DM) and type-2 diabetes mellitus (T2DM). For verification of the proposed model, experimental data from fifty patients, acquired from a local hospital in semi-structured format, is used. First, the data is transformed into structured format and then used for mining prediction rules. Rough set theory (RST) based techniques and algorithms are used to mine the prediction rules. During the online execution phase of the model, these rules are used to predict T1DM and T2DM for new patients. Furthermore, the proposed model assists physicians to manage diabetes using knowledge extracted from online diabetes guidelines. Correlation-based trend analysis techniques are used to manage diabetic observations. Experimental results demonstrate that the proposed model outperforms the existing methods with 95.9% average and balanced accuracies. PMID:26151207

  6. Modeling the formation process of grouping stimuli sets through cortical columns and microcircuits to feature neurons.

    PubMed

    Klefenz, Frank; Williamson, Adam

    2013-01-01

    A computational model of a self-structuring neuronal net is presented in which repetitively applied pattern sets induce the formation of cortical columns and microcircuits which decode distinct patterns after a learning phase. In a case study, it is demonstrated how specific neurons in a feature classifier layer become orientation selective if they receive bar patterns of different slopes from an input layer. The input layer is mapped and intertwined by self-evolving neuronal microcircuits to the feature classifier layer. In this topical overview, several models are discussed which indicate that the net formation converges in its functionality to a mathematical transform which maps the input pattern space to a feature representing output space. The self-learning of the mathematical transform is discussed and its implications are interpreted. Model assumptions are deduced which serve as a guide to apply model derived repetitive stimuli pattern sets to in vitro cultures of neuron ensembles to condition them to learn and execute a mathematical transform.

  7. Modeling the Formation Process of Grouping Stimuli Sets through Cortical Columns and Microcircuits to Feature Neurons

    PubMed Central

    Williamson, Adam

    2013-01-01

    A computational model of a self-structuring neuronal net is presented in which repetitively applied pattern sets induce the formation of cortical columns and microcircuits which decode distinct patterns after a learning phase. In a case study, it is demonstrated how specific neurons in a feature classifier layer become orientation selective if they receive bar patterns of different slopes from an input layer. The input layer is mapped and intertwined by self-evolving neuronal microcircuits to the feature classifier layer. In this topical overview, several models are discussed which indicate that the net formation converges in its functionality to a mathematical transform which maps the input pattern space to a feature representing output space. The self-learning of the mathematical transform is discussed and its implications are interpreted. Model assumptions are deduced which serve as a guide to apply model derived repetitive stimuli pattern sets to in vitro cultures of neuron ensembles to condition them to learn and execute a mathematical transform. PMID:24369455

  8. Scientific Playworlds: a Model of Teaching Science in Play-Based Settings

    NASA Astrophysics Data System (ADS)

    Fleer, Marilyn

    2017-09-01

    Eminent scientists, like Einstein, worked with theoretical contradiction, thought experiments, mental models and visualisation—all characteristics of children's play. Supporting children's play is a strength of early childhood teachers. Promising research shows a link between imagination in science and imagination in play. A case study of 3 preschool teachers and 26 children (3.6-5.9 years; mean age of 4.6 years) over 6 weeks was undertaken, generating 59.6 h of digital observations and 788 photographs of play practices. The research sought to understand (1) how imaginative play promotes scientific learning and (2) examined how teachers engaged children in scientific play. Although play pedagogy is a strength of early childhood teachers, it was found that transforming imaginary situations into scientific narratives requires different pedagogical characteristics. The study found that the building of collective scientific narratives alongside of discourses of wondering were key determinants of science learning in play-based settings. Specifically, the pedagogical principles of using a cultural device that mirrors the science experiences, creating imaginary scientific situations, collectively building scientific problem situations, and imagining the relations between observable contexts and non-observable concepts, changed everyday practices into a scientific narrative and engagement. It is argued that these unique pedagogical characteristics promote scientific narratives in play-based settings. An approach, named as Scientific Playworlds, is presented as a possible model for teaching science in play-based settings.

  9. QSAR modeling of a set of pyrazinoate esters as antituberculosis prodrugs.

    PubMed

    Fernandes, João P S; Pasqualoto, Kerly F M; Felli, Veni M A; Ferreira, Elizabeth I; Brandt, Carlos A

    2010-02-01

    Tuberculosis is an infection caused mainly by Mycobacterium tuberculosis. A first-line antimycobacterial drug is pyrazinamide (PZA), which acts partially as a prodrug activated by a pyrazinamidase releasing the active agent, pyrazinoic acid (POA). As pyrazinoic acid presents some difficulty to cross the mycobacterial cell wall, and also the pyrazinamide-resistant strains do not express the pyrazinamidase, a set of pyrazinoic acid esters have been evaluated as antimycobacterial agents. In this work, a QSAR approach was applied to a set of forty-three pyrazinoates against M. tuberculosis ATCC 27294, using genetic algorithm function and partial least squares regression (WOLF 5.5 program). The independent variables selected were the Balaban index (J), calculated n-octanol/water partition coefficient (ClogP), van-der-Waals surface area, dipole moment, and stretching-energy contribution. The final QSAR model (N = 32, r(2) = 0.68, q(2) = 0.59, LOF = 0.25, and LSE = 0.19) was fully validated employing leave-N-out cross-validation and y-scrambling techniques. The test set (N = 11) presented an external prediction power of 73%. In conclusion, the QSAR model generated can be used as a valuable tool to optimize the activity of future pyrazinoic acid esters in the designing of new antituberculosis agents.

  10. Beyond Maximum Independent Set: AN Extended Model for Point-Feature Label Placement

    NASA Astrophysics Data System (ADS)

    Haunert, Jan-Henrik; Wolff, Alexander

    2016-06-01

    Map labeling is a classical problem of cartography that has frequently been approached by combinatorial optimization. Given a set of features in the map and for each feature a set of label candidates, a common problem is to select an independent set of labels (that is, a labeling without label-label overlaps) that contains as many labels as possible and at most one label for each feature. To obtain solutions of high cartographic quality, the labels can be weighted and one can maximize the total weight (rather than the number) of the selected labels. We argue, however, that when maximizing the weight of the labeling, interdependences between labels are insufficiently addressed. Furthermore, in a maximum-weight labeling, the labels tend to be densely packed and thus the map background can be occluded too much. We propose extensions of an existing model to overcome these limitations. Since even without our extensions the problem is NP-hard, we cannot hope for an efficient exact algorithm for the problem. Therefore, we present a formalization of our model as an integer linear program (ILP). This allows us to compute optimal solutions in reasonable time, which we demonstrate for randomly generated instances.

  11. How can mathematical models advance tuberculosis control in high HIV prevalence settings?

    PubMed

    Houben, R M G J; Dowdy, D W; Vassall, A; Cohen, T; Nicol, M P; Granich, R M; Shea, J E; Eckhoff, P; Dye, C; Kimerling, M E; White, R G

    2014-05-01

    Existing approaches to tuberculosis (TB) control have been no more than partially successful in areas with high human immunodeficiency virus (HIV) prevalence. In the context of increasingly constrained resources, mathematical modelling can augment understanding and support policy for implementing those strategies that are most likely to bring public health and economic benefits. In this paper, we present an overview of past and recent contributions of TB modelling in this key area, and suggest a way forward through a modelling research agenda that supports a more effective response to the TB-HIV epidemic, based on expert discussions at a meeting convened by the TB Modelling and Analysis Consortium. The research agenda identified high-priority areas for future modelling efforts, including 1) the difficult diagnosis and high mortality of TB-HIV; 2) the high risk of disease progression; 3) TB health systems in high HIV prevalence settings; 4) uncertainty in the natural progression of TB-HIV; and 5) combined interventions for TB-HIV. Efficient and rapid progress towards completion of this modelling agenda will require co-ordination between the modelling community and key stakeholders, including advocates, health policy makers, donors and national or regional finance officials. A continuing dialogue will ensure that new results are effectively communicated and new policy-relevant questions are addressed swiftly.

  12. Impact of structural and psychological empowerment on job strain in nursing work settings: expanding Kanter's model.

    PubMed

    Laschinger, H K; Finegan, J; Shamian, J; Wilk, P

    2001-05-01

    In this study, we tested an expanded model of Kanter's structural empowerment, which specified the relationships among structural and psychological empowerment, job strain, and work satisfaction. Strategies proposed in Kanter's empowerment theory have the potential to reduce job strain and improve employee work satisfaction and performance in current restructured healthcare settings. The addition to the model of psychological empowerment as an outcome of structural empowerment provides an understanding of the intervening mechanisms between structural work conditions and important organizational outcomes. A predictive, nonexperimental design was used to test the model in a random sample of 404 Canadian staff nurses. The Conditions of Work Effectiveness Questionnaire, the Psychological Empowerment Questionnaire, the Job Content Questionnaire, and the Global Satisfaction Scale were used to measure the major study variables. Structural equation modelling analyses revealed a good fit of the hypothesized model to the data based on various fit indices (chi 2 = 1140, df = 545, chi 2/df ratio = 2.09, CFI = 0.986, RMSEA = 0.050). The amount of variance accounted for in the model was 58%. Staff nurses felt that structural empowerment in their workplace resulted in higher levels of psychological empowerment. These heightened feelings of psychological empowerment in turn strongly influenced job strain and work satisfaction. However, job strain did not have a direct effect on work satisfaction. These results provide initial support for an expanded model of organizational empowerment and offer a broader understanding of the empowerment process.

  13. How can mathematical models advance tuberculosis control in high HIV prevalence settings?

    PubMed Central

    Dowdy, D. W.; Vassall, A.; Cohen, T.; Nicol, M. P.; Granich, R. M.; Shea, J. E.; Eckhoff, P.; Dye, C.; Kimerling, M. E.; White, R. G.

    2014-01-01

    SUMMARY Existing approaches to tuberculosis (TB) control have been no more than partially successful in areas with high human immunodeficiency virus (HIV) prevalence. In the context of increasingly constrained resources, mathematical modelling can augment understanding and support policy for implementing those strategies that are most likely to bring public health and economic benefits. In this paper, we present an overview of past and recent contributions of TB modelling in this key area, and suggest a way forward through a modelling research agenda that supports a more effective response to the TB-HIV epidemic, based on expert discussions at a meeting convened by the TB Modelling and Analysis Consortium. The research agenda identified high-priority areas for future modelling efforts, including 1) the difficult diagnosis and high mortality of TB-HIV; 2) the high risk of disease progression; 3) TB health systems in high HIV prevalence settings; 4) uncertainty in the natural progression of TB-HIV; and 5) combined interventions for TB-HIV. Efficient and rapid progress towards completion of this modelling agenda will require co-ordination between the modelling community and key stakeholders, including advocates, health policy makers, donors and national or regional finance officials. A continuing dialogue will ensure that new results are effectively communicated and new policy-relevant questions are addressed swiftly. PMID:24903784

  14. Modelling reverberation mapping data - II. Dynamical modelling of the Lick AGN Monitoring Project 2008 data set

    NASA Astrophysics Data System (ADS)

    Pancoast, Anna; Brewer, Brendon J.; Treu, Tommaso; Park, Daeseong; Barth, Aaron J.; Bentz, Misty C.; Woo, Jong-Hak

    2014-12-01

    We present dynamical modelling of the broad-line region (BLR) for a sample of five Seyfert 1 galaxie