WorldWideScience

Sample records for models show consistent

  1. Consistent model driven architecture

    Science.gov (United States)

    Niepostyn, Stanisław J.

    2015-09-01

    The goal of the MDA is to produce software systems from abstract models in a way where human interaction is restricted to a minimum. These abstract models are based on the UML language. However, the semantics of UML models is defined in a natural language. Subsequently the verification of consistency of these diagrams is needed in order to identify errors in requirements at the early stage of the development process. The verification of consistency is difficult due to a semi-formal nature of UML diagrams. We propose automatic verification of consistency of the series of UML diagrams originating from abstract models implemented with our consistency rules. This Consistent Model Driven Architecture approach enables us to generate automatically complete workflow applications from consistent and complete models developed from abstract models (e.g. Business Context Diagram). Therefore, our method can be used to check practicability (feasibility) of software architecture models.

  2. Consistently Showing Your Best Side? Intra-individual Consistency in #Selfie Pose Orientation

    Science.gov (United States)

    Lindell, Annukka K.

    2017-01-01

    Painted and photographic portraits of others show an asymmetric bias: people favor their left cheek. Both experimental and database studies confirm that the left cheek bias extends to selfies. To date all such selfie studies have been cross-sectional; whether individual selfie-takers tend to consistently favor the same pose orientation, or switch between multiple poses, remains to be determined. The present study thus examined intra-individual consistency in selfie pose orientations. Two hundred selfie-taking participants (100 male and 100 female) were identified by searching #selfie on Instagram. The most recent 10 single-subject selfies for the each of the participants were selected and coded for type of selfie (normal; mirror) and pose orientation (left, midline, right), resulting in a sample of 2000 selfies. Results indicated that selfie-takers do tend to consistently adopt a preferred pose orientation (α = 0.72), with more participants showing an overall left cheek bias (41%) than would be expected by chance (overall right cheek bias = 31.5%; overall midline bias = 19.5%; no overall bias = 8%). Logistic regression modellng, controlling for the repeated measure of participant identity, indicated that sex did not affect pose orientation. However, selfie type proved a significant predictor when comparing left and right cheek poses, with a stronger left cheek bias for mirror than normal selfies. Overall, these novel findings indicate that selfie-takers show intra-individual consistency in pose orientation, and in addition, replicate the previously reported left cheek bias for selfies and other types of portrait, confirming that the left cheek bias also presents within individuals’ selfie corpora. PMID:28270790

  3. ERBE bidirectional model consistency check

    Science.gov (United States)

    Baldwin, D. G.; Coakley, J. A., Jr.

    1986-01-01

    A short analysis is presented of Earth Radiation Budget Experiment (ERBE) errors inherent in the directional models used for data interpretation. The models were all developed on the basis of experience with the Nimbus-7 ERB experiment, which had a spatial resolution one-third that of ERBE instrumentation. A pseudo-directional model is defined to simulate the ERBE scanner data, using the assumptions that the average radiant exitance for any particular scene is independent of the viewing geometry, geographic location and time the data is collected. The directionality of the view angle and solar zenith angle is accounted for by a method of bins.

  4. Consistent Estimation of Partition Markov Models

    Directory of Open Access Journals (Sweden)

    Jesús E. García

    2017-04-01

    Full Text Available The Partition Markov Model characterizes the process by a partition L of the state space, where the elements in each part of L share the same transition probability to an arbitrary element in the alphabet. This model aims to answer the following questions: what is the minimal number of parameters needed to specify a Markov chain and how to estimate these parameters. In order to answer these questions, we build a consistent strategy for model selection which consist of: giving a size n realization of the process, finding a model within the Partition Markov class, with a minimal number of parts to represent the process law. From the strategy, we derive a measure that establishes a metric in the state space. In addition, we show that if the law of the process is Markovian, then, eventually, when n goes to infinity, L will be retrieved. We show an application to model internet navigation patterns.

  5. Self-consistent asset pricing models

    Science.gov (United States)

    Malevergne, Y.; Sornette, D.

    2007-08-01

    We discuss the foundations of factor or regression models in the light of the self-consistency condition that the market portfolio (and more generally the risk factors) is (are) constituted of the assets whose returns it is (they are) supposed to explain. As already reported in several articles, self-consistency implies correlations between the return disturbances. As a consequence, the alphas and betas of the factor model are unobservable. Self-consistency leads to renormalized betas with zero effective alphas, which are observable with standard OLS regressions. When the conditions derived from internal consistency are not met, the model is necessarily incomplete, which means that some sources of risk cannot be replicated (or hedged) by a portfolio of stocks traded on the market, even for infinite economies. Analytical derivations and numerical simulations show that, for arbitrary choices of the proxy which are different from the true market portfolio, a modified linear regression holds with a non-zero value αi at the origin between an asset i's return and the proxy's return. Self-consistency also introduces “orthogonality” and “normality” conditions linking the betas, alphas (as well as the residuals) and the weights of the proxy portfolio. Two diagnostics based on these orthogonality and normality conditions are implemented on a basket of 323 assets which have been components of the S&P500 in the period from January 1990 to February 2005. These two diagnostics show interesting departures from dynamical self-consistency starting about 2 years before the end of the Internet bubble. Assuming that the CAPM holds with the self-consistency condition, the OLS method automatically obeys the resulting orthogonality and normality conditions and therefore provides a simple way to self-consistently assess the parameters of the model by using proxy portfolios made only of the assets which are used in the CAPM regressions. Finally, the factor decomposition with the

  6. Freshwater pearl mussels show plasticity of responses to different predation risks but also show consistent individual differences in responsiveness.

    Science.gov (United States)

    Wilson, Conor D; Arnott, Gareth; Elwood, Robert W

    2012-03-01

    Animals often show behavioural plasticity with respect to predation risk but also show behavioural syndromes in terms of consistency of responses to different stimuli. We examine these features in the freshwater pearl mussel. These bivalves often aggregate presumably to reduce predation risk to each individual. Predation risk, however, will be higher in the presence of predator cues. Here we use dimming light, vibration and touch as novel stimuli to examine the trade-off between motivation to feed and motivation to avoid predation. We present two experiments that each use three sequential novel stimuli to cause the mussels to close their valves and hence cease feeding. We find that mussels within a group showed shorter closure times than solitary mussels, consistent with decreased vulnerability to predation in group-living individuals. Mussels exposed to the odour of a predatory crayfish showed longer closures than control mussels, highlighting the predator assessment abilities of this species. However, individuals showed significant consistency in their closure responses across the trial series, in line with behavioural syndrome theory. Our results show that bivalves trade-off feeding and predator avoidance according to predation risk but the degree to which this is achieved is constrained by behavioural consistency. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Consistency of the MLE under mixture models

    OpenAIRE

    Chen, Jiahua

    2016-01-01

    The large-sample properties of likelihood-based statistical inference under mixture models have received much attention from statisticians. Although the consistency of the nonparametric MLE is regarded as a standard conclusion, many researchers ignore the precise conditions required on the mixture model. An incorrect claim of consistency can lead to false conclusions even if the mixture model under investigation seems well behaved. Under a finite normal mixture model, for instance, the consis...

  8. Consistent spectroscopy for a extended gauge model

    International Nuclear Information System (INIS)

    Oliveira Neto, G. de.

    1990-11-01

    The consistent spectroscopy was obtained with a Lagrangian constructed with vector fields with a U(1) group extended symmetry. As consistent spectroscopy is understood the determination of quantum physical properties described by the model in an manner independent from the possible parametrizations adopted in their description. (L.C.J.A.)

  9. Consistent Stochastic Modelling of Meteocean Design Parameters

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Sterndorff, M. J.

    2000-01-01

    Consistent stochastic models of metocean design parameters and their directional dependencies are essential for reliability assessment of offshore structures. In this paper a stochastic model for the annual maximum values of the significant wave height, and the associated wind velocity, current...

  10. Developing consistent pronunciation models for phonemic variants

    CSIR Research Space (South Africa)

    Davel, M

    2006-09-01

    Full Text Available from a lexicon containing variants. In this paper we (the authors) address both these issues by creating ‘pseudo-phonemes’ associated with sets of ‘generation restriction rules’ to model those pronunciations that are consistently realised as two or more...

  11. Functional diversity and community assembly of river invertebrates show globally consistent responses to decreasing glacier cover.

    Science.gov (United States)

    Brown, Lee E; Khamis, Kieran; Wilkes, Martin; Blaen, Phillip; Brittain, John E; Carrivick, Jonathan L; Fell, Sarah; Friberg, Nikolai; Füreder, Leopold; Gislason, Gisli M; Hainie, Sarah; Hannah, David M; James, William H M; Lencioni, Valeria; Olafsson, Jon S; Robinson, Christopher T; Saltveit, Svein J; Thompson, Craig; Milner, Alexander M

    2018-02-01

    Global change threatens invertebrate biodiversity and its central role in numerous ecosystem functions and services. Functional trait analyses have been advocated to uncover global mechanisms behind biodiversity responses to environmental change, but the application of this approach for invertebrates is underdeveloped relative to other organism groups. From an evaluation of 363 records comprising >1.23 million invertebrates collected from rivers across nine biogeographic regions on three continents, consistent responses of community trait composition and diversity to replicated gradients of reduced glacier cover are demonstrated. After accounting for a systematic regional effect of latitude, the processes shaping river invertebrate functional diversity are globally consistent. Analyses nested within individual regions identified an increase in functional diversity as glacier cover decreases. Community assembly models demonstrated that dispersal limitation was the dominant process underlying these patterns, although environmental filtering was also evident in highly glacierized basins. These findings indicate that predictable mechanisms govern river invertebrate community responses to decreasing glacier cover globally.

  12. Self-consistent model of confinement

    International Nuclear Information System (INIS)

    Swift, A.R.

    1988-01-01

    A model of the large-spatial-distance, zero--three-momentum, limit of QCD is developed from the hypothesis that there is an infrared singularity. Single quarks and gluons do not propagate because they have infinite energy after renormalization. The Hamiltonian formulation of the path integral is used to quantize QCD with physical, nonpropagating fields. Perturbation theory in the infrared limit is simplified by the absence of self-energy insertions and by the suppression of large classes of diagrams due to vanishing propagators. Remaining terms in the perturbation series are resummed to produce a set of nonlinear, renormalizable integral equations which fix both the confining interaction and the physical propagators. Solutions demonstrate the self-consistency of the concepts of an infrared singularity and nonpropagating fields. The Wilson loop is calculated to provide a general proof of confinement. Bethe-Salpeter equations for quark-antiquark pairs and for two gluons have finite-energy solutions in the color-singlet channel. The choice of gauge is addressed in detail. Large classes of corrections to the model are discussed and shown to support self-consistency

  13. A thermodynamically consistent model for magnetic hysteresis

    International Nuclear Information System (INIS)

    Ho, Kwangsoo

    2014-01-01

    A phenomenological constitutive model is presented to describe the magnetization curve within the context of thermodynamics. Due to the phenomenological analogy between the magnetic hysteresis and the stress hysteresis, the basic structure of the proposed model comes from rate-dependent plasticity in continuum mechanics, namely viscoplasticity. The total magnetic flux density is assumed to be the sum of reversible and irreversible parts. The model introduces the evolution laws of two internal state variables to incorporate the effect of the ever-changing internal microstructure on the current state. The conception originated from viscoplasticity enables the frequency dependence of the hysteresis curve to be modeled. - Highlights: • A constitutive model is proposed within the framework of thermodynamic principles. • The basic structure of formulation is originated from the rate-dependent plasticity. • Decomposition of the magnetic flux into reversible and irreversible parts is assumed. • Constitutive model reproduces the frequency dependency of magnetic hysteresis

  14. Consistency and flexibility in solving spatial tasks: different horses show different cognitive styles.

    Science.gov (United States)

    Baragli, Paolo; Vitale, Valentina; Sighieri, Claudio; Lanata, Antonio; Palagi, Elisabetta; Reddon, Adam R

    2017-11-29

    Individual animals vary in their behaviour and reactions to novel situations. These differences may extend to differences in cognition among individuals. We tested twenty-six horses for their ability to detour around symmetric and asymmetric obstacles. All of the animals were able to get around the barrier to reach a food target, but varied in their approach. Some horses moved slowly but were more accurate in choosing the shortest way. Other horses acted quickly, consistently detoured in the same direction, and did not reliably choose the shortest way. The remaining horses shifted from a faster, directionally consistent response with the symmetric barrier, to a slower but more accurate response with the asymmetric barrier. The asymmetric barrier induced a reduction in heart rate variability, suggesting that this is a more demanding task. The different approaches used to solve the asymmetric task may reflect distinct cognitive styles in horses, which vary among individuals, and could be linked to different personality traits. Understanding equine behaviour and cognition can inform horse welfare and management.

  15. Subunit Vaccines Consisting of Antigens from Dormant and Replicating Bacteria Show Promising Therapeutic Effect against Mycobacterium Bovis BCG Latent Infection.

    Science.gov (United States)

    Li, F; Kang, H; Li, J; Zhang, D; Zhang, Y; Dannenberg, A M; Liu, X; Niu, H; Ma, L; Tang, R; Han, X; Gan, C; Ma, X; Tan, J; Zhu, B

    2017-06-01

    To screen effective antigens as therapeutic subunit vaccines against Mycobacterium latent infection, we did bioinformatics analysis and literature review to identify effective antigens and evaluated the immunogenicity of five antigens highly expressed in dormant bacteria, which included Rv2031c (HspX), Rv2626c (Hrp1), Rv2007c (FdxA), Rv1738 and Rv3130c. Then, several fusion proteins such as Rv2007c-Rv2626c (F6), Rv2031c-Rv1738-Rv1733c (H83), ESAT6-Rv1738-Rv2626c (LT40), ESAT6-Ag85B-MPT64 -Mtb8.4 (EAMM), and EAMM-Rv2626c (LT70) were constructed and their therapeutic effects were evaluated in pulmonary Mycobacterium bovis Bacilli Calmette-Guérin (BCG) - latently infected rabbit or mouse models. The results showed that EAMM and F6 plus H83 had therapeutic effect against BCG latent infection in the rabbit model, respectively, and that the combination of EAMM with F6 plus H83 significantly reduced the bacterial load. In addition, the fusion proteins LT40 and LT70 consisting of multistage antigens showed promising therapeutic effects in the mouse model. We conclude that subunit vaccines consisting of both latency and replicating-associated antigens show promising therapeutic effects in BCG latent infection animal models. © 2017 The Foundation for the Scandinavian Journal of Immunology.

  16. Parametrization of model consistant expectations in the Sidrauski model

    NARCIS (Netherlands)

    Hoogenveen, Victoria; Sterken, Elmer

    1996-01-01

    This paper discusses a cubic parametrisation of model consistent expectations in a nonlinear dynamic monetary growth model. The so-called Sidrauski model links money, inflation and consumption growth. Iterative least squares combined with simulation is used to address the alleged impact of inflation

  17. Standard Model Vacuum Stability and Weyl Consistency Conditions

    DEFF Research Database (Denmark)

    Antipin, Oleg; Gillioz, Marc; Krog, Jens

    2013-01-01

    At high energy the standard model possesses conformal symmetry at the classical level. This is reflected at the quantum level by relations between the different beta functions of the model. These relations are known as the Weyl consistency conditions. We show that it is possible to satisfy them...... order by order in perturbation theory, provided that a suitable coupling constant counting scheme is used. As a direct phenomenological application, we study the stability of the standard model vacuum at high energies and compare with previous computations violating the Weyl consistency conditions....

  18. Consistent Alignment of World Embedding Models

    Science.gov (United States)

    2017-03-02

    MIT Lincoln Laboratory 244 Wood Street Lexington, MA 02421, USA ABSTRACT Word embedding models offer continuous vector representations that can...generated synthetic data points. This generative process is inspired by the observation that a variety of linguistic relationships is captured by simple...as images , and genomic data. In Wang et al. (2016) manifold alignment techniques are used to discover logical relationships in supervised settings. We

  19. Self-Consistent Models of Accretion Disks

    Science.gov (United States)

    Narayan, Ramesh

    2000-01-01

    Research was carried out on several topics in the theory of astrophysical accretion flows around black holes, neutron stars and white dwarfs. The focus of our effort was the advection-dominated accretion flow (ADAF) model which the PI and his collaborators proposed and developed over the last several years. Our group completed a total of 46 papers, of which 36 are in refereed journals and 12 are in conference proceedings. All the papers have either already appeared in print or are in press.

  20. Consistency test of the standard model

    International Nuclear Information System (INIS)

    Pawlowski, M.; Raczka, R.

    1997-01-01

    If the 'Higgs mass' is not the physical mass of a real particle but rather an effective ultraviolet cutoff then a process energy dependence of this cutoff must be admitted. Precision data from at least two energy scale experimental points are necessary to test this hypothesis. The first set of precision data is provided by the Z-boson peak experiments. We argue that the second set can be given by 10-20 GeV e + e - colliders. We pay attention to the special role of tau polarization experiments that can be sensitive to the 'Higgs mass' for a sample of ∼ 10 8 produced tau pairs. We argue that such a study may be regarded as a negative selfconsistency test of the Standard Model and of most of its extensions

  1. Simplified models for dark matter face their consistent completions

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, Dorival; Machado, Pedro A. N.; No, Jose Miguel

    2017-03-01

    Simplified dark matter models have been recently advocated as a powerful tool to exploit the complementarity between dark matter direct detection, indirect detection and LHC experimental probes. Focusing on pseudoscalar mediators between the dark and visible sectors, we show that the simplified dark matter model phenomenology departs significantly from that of consistent ${SU(2)_{\\mathrm{L}} \\times U(1)_{\\mathrm{Y}}}$ gauge invariant completions. We discuss the key physics simplified models fail to capture, and its impact on LHC searches. Notably, we show that resonant mono-Z searches provide competitive sensitivities to standard mono-jet analyses at $13$ TeV LHC.

  2. The Work Role Functioning Questionnaire v2.0 Showed Consistent Factor Structure Across Six Working Samples.

    Science.gov (United States)

    Abma, Femke I; Bültmann, Ute; Amick Iii, Benjamin C; Arends, Iris; Dorland, Heleen F; Flach, Peter A; van der Klink, Jac J L; van de Ven, Hardy A; Bjørner, Jakob Bue

    2017-09-09

    Objective The Work Role Functioning Questionnaire v2.0 (WRFQ) is an outcome measure linking a persons' health to the ability to meet work demands in the twenty-first century. We aimed to examine the construct validity of the WRFQ in a heterogeneous set of working samples in the Netherlands with mixed clinical conditions and job types to evaluate the comparability of the scale structure. Methods Confirmatory factor and multi-group analyses were conducted in six cross-sectional working samples (total N = 2433) to evaluate and compare a five-factor model structure of the WRFQ (work scheduling demands, output demands, physical demands, mental and social demands, and flexibility demands). Model fit indices were calculated based on RMSEA ≤ 0.08 and CFI ≥ 0.95. After fitting the five-factor model, the multidimensional structure of the instrument was evaluated across samples using a second order factor model. Results The factor structure was robust across samples and a multi-group model had adequate fit (RMSEA = 0.63, CFI = 0.972). In sample specific analyses, minor modifications were necessary in three samples (final RMSEA 0.055-0.080, final CFI between 0.955 and 0.989). Applying the previous first order specifications, a second order factor model had adequate fit in all samples. Conclusion A five-factor model of the WRFQ showed consistent structural validity across samples. A second order factor model showed adequate fit, but the second order factor loadings varied across samples. Therefore subscale scores are recommended to compare across different clinical and working samples.

  3. Detection and quantification of flow consistency in business process models

    DEFF Research Database (Denmark)

    Burattin, Andrea; Bernstein, Vered; Neurauter, Manuel

    2017-01-01

    , to show how such features can be quantified into computational metrics, which are applicable to business process models. We focus on one particular feature, consistency of flow direction, and show the challenges that arise when transforming it into a precise metric. We propose three different metrics......Business process models abstract complex business processes by representing them as graphical models. Their layout, as determined by the modeler, may have an effect when these models are used. However, this effect is currently not fully understood. In order to systematically study this effect......, a basic set of measurable key visual features is proposed, depicting the layout properties that are meaningful to the human user. The aim of this research is thus twofold: first, to empirically identify key visual features of business process models which are perceived as meaningful to the user and second...

  4. Diagnosing a Strong-Fault Model by Conflict and Consistency.

    Science.gov (United States)

    Zhang, Wenfeng; Zhao, Qi; Zhao, Hongbo; Zhou, Gan; Feng, Wenquan

    2018-03-29

    The diagnosis method for a weak-fault model with only normal behaviors of each component has evolved over decades. However, many systems now demand a strong-fault models, the fault modes of which have specific behaviors as well. It is difficult to diagnose a strong-fault model due to its non-monotonicity. Currently, diagnosis methods usually employ conflicts to isolate possible fault and the process can be expedited when some observed output is consistent with the model's prediction where the consistency indicates probably normal components. This paper solves the problem of efficiently diagnosing a strong-fault model by proposing a novel Logic-based Truth Maintenance System (LTMS) with two search approaches based on conflict and consistency. At the beginning, the original a strong-fault model is encoded by Boolean variables and converted into Conjunctive Normal Form (CNF). Then the proposed LTMS is employed to reason over CNF and find multiple minimal conflicts and maximal consistencies when there exists fault. The search approaches offer the best candidate efficiency based on the reasoning result until the diagnosis results are obtained. The completeness, coverage, correctness and complexity of the proposals are analyzed theoretically to show their strength and weakness. Finally, the proposed approaches are demonstrated by applying them to a real-world domain-the heat control unit of a spacecraft-where the proposed methods are significantly better than best first and conflict directly with A* search methods.

  5. A Consistent Pricing Model for Index Options and Volatility Derivatives

    DEFF Research Database (Denmark)

    Kokholm, Thomas

    We propose a flexible modeling framework for the joint dynamics of an index and a set of forward variance swap rates written on this index. Our model reproduces various empirically observed properties of variance swap dynamics and enables volatility derivatives and options on the underlying index...... to be priced consistently, while allowing for jumps in volatility and returns. An affine specification using Lévy processes as building blocks leads to analytically tractable pricing formulas for volatility derivatives, such as VIX options, as well as efficient numerical methods for pricing of European options...... on the underlying asset. The model has the convenient feature of decoupling the vanilla skews from spot/volatility correlations and allowing for different conditional correlations in large and small spot/volatility moves. We show that our model can simultaneously fit prices of European options on S&P 500 across...

  6. A Consistent Pricing Model for Index Options and Volatility Derivatives

    DEFF Research Database (Denmark)

    Cont, Rama; Kokholm, Thomas

    2013-01-01

    We propose a flexible modeling framework for the joint dynamics of an index and a set of forward variance swap rates written on this index. Our model reproduces various empirically observed properties of variance swap dynamics and enables volatility derivatives and options on the underlying index...... to be priced consistently, while allowing for jumps in volatility and returns. An affine specification using Lévy processes as building blocks leads to analytically tractable pricing formulas for volatility derivatives, such as VIX options, as well as efficient numerical methods for pricing of European options...... on the underlying asset. The model has the convenient feature of decoupling the vanilla skews from spot/volatility correlations and allowing for different conditional correlations in large and small spot/volatility moves. We show that our model can simultaneously fit prices of European options on S&P 500 across...

  7. A Consistent Pricing Model for Index Options and Volatility Derivatives

    DEFF Research Database (Denmark)

    Cont, Rama; Kokholm, Thomas

    We propose and study a flexible modeling framework for the joint dynamics of an index and a set of forward variance swap rates written on this index, allowing options on forward variance swaps and options on the underlying index to be priced consistently. Our model reproduces various empirically...... observed properties of variance swap dynamics and allows for jumps in volatility and returns. An affine specification using L´evy processes as building blocks leads to analytically tractable pricing formulas for options on variance swaps as well as efficient numerical methods for pricing of European...... options on the underlying asset. The model has the convenient feature of decoupling the vanilla skews from spot/volatility correlations and allowing for different conditional correlations in large and small spot/volatility moves. We show that our model can simultaneously fit prices of European options...

  8. Are paleoclimate model ensembles consistent with the MARGO data synthesis?

    Directory of Open Access Journals (Sweden)

    J. C. Hargreaves

    2011-08-01

    Full Text Available We investigate the consistency of various ensembles of climate model simulations with the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface (MARGO sea surface temperature data synthesis. We discover that while two multi-model ensembles, created through the Paleoclimate Model Intercomparison Projects (PMIP and PMIP2, pass our simple tests of reliability, an ensemble based on parameter variation in a single model does not perform so well. We show that accounting for observational uncertainty in the MARGO database is of prime importance for correctly evaluating the ensembles. Perhaps surprisingly, the inclusion of a coupled dynamical ocean (compared to the use of a slab ocean does not appear to cause a wider spread in the sea surface temperature anomalies, but rather causes systematic changes with more heat transported north in the Atlantic. There is weak evidence that the sea surface temperature data may be more consistent with meridional overturning in the North Atlantic being similar for the LGM and the present day. However, the small size of the PMIP2 ensemble prevents any statistically significant results from being obtained.

  9. Development of a Consistent and Reproducible Porcine Scald Burn Model

    Science.gov (United States)

    Kempf, Margit; Kimble, Roy; Cuttle, Leila

    2016-01-01

    There are very few porcine burn models that replicate scald injuries similar to those encountered by children. We have developed a robust porcine burn model capable of creating reproducible scald burns for a wide range of burn conditions. The study was conducted with juvenile Large White pigs, creating replicates of burn combinations; 50°C for 1, 2, 5 and 10 minutes and 60°C, 70°C, 80°C and 90°C for 5 seconds. Visual wound examination, biopsies and Laser Doppler Imaging were performed at 1, 24 hours and at 3 and 7 days post-burn. A consistent water temperature was maintained within the scald device for long durations (49.8 ± 0.1°C when set at 50°C). The macroscopic and histologic appearance was consistent between replicates of burn conditions. For 50°C water, 10 minute duration burns showed significantly deeper tissue injury than all shorter durations at 24 hours post-burn (p ≤ 0.0001), with damage seen to increase until day 3 post-burn. For 5 second duration burns, by day 7 post-burn the 80°C and 90°C scalds had damage detected significantly deeper in the tissue than the 70°C scalds (p ≤ 0.001). A reliable and safe model of porcine scald burn injury has been successfully developed. The novel apparatus with continually refreshed water improves consistency of scald creation for long exposure times. This model allows the pathophysiology of scald burn wound creation and progression to be examined. PMID:27612153

  10. A self-consistent spin-diffusion model for micromagnetics

    KAUST Repository

    Abert, Claas

    2016-12-17

    We propose a three-dimensional micromagnetic model that dynamically solves the Landau-Lifshitz-Gilbert equation coupled to the full spin-diffusion equation. In contrast to previous methods, we solve for the magnetization dynamics and the electric potential in a self-consistent fashion. This treatment allows for an accurate description of magnetization dependent resistance changes. Moreover, the presented algorithm describes both spin accumulation due to smooth magnetization transitions and due to material interfaces as in multilayer structures. The model and its finite-element implementation are validated by current driven motion of a magnetic vortex structure. In a second experiment, the resistivity of a magnetic multilayer structure in dependence of the tilting angle of the magnetization in the different layers is investigated. Both examples show good agreement with reference simulations and experiments respectively.

  11. Self-Consistent Dynamical Model of the Broad Line Region

    International Nuclear Information System (INIS)

    Czerny, Bozena; Li, Yan-Rong; Sredzinska, Justyna; Hryniewicz, Krzysztof; Panda, Swayam; Wildy, Conor; Karas, Vladimir

    2017-01-01

    We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency) and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.

  12. Consistent constraints on the Standard Model Effective Field Theory

    Energy Technology Data Exchange (ETDEWEB)

    Berthier, Laure; Trott, Michael [Niels Bohr International Academy, University of Copenhagen,Blegdamsvej 17, DK-2100 Copenhagen (Denmark)

    2016-02-10

    We develop the global constraint picture in the (linear) effective field theory generalisation of the Standard Model, incorporating data from detectors that operated at PEP, PETRA, TRISTAN, SpS, Tevatron, SLAC, LEPI and LEP II, as well as low energy precision data. We fit one hundred and three observables. We develop a theory error metric for this effective field theory, which is required when constraints on parameters at leading order in the power counting are to be pushed to the percent level, or beyond, unless the cut off scale is assumed to be large, Λ≳ 3 TeV. We more consistently incorporate theoretical errors in this work, avoiding this assumption, and as a direct consequence bounds on some leading parameters are relaxed. We show how an S,T analysis is modified by the theory errors we include as an illustrative example.

  13. Self-Consistent Dynamical Model of the Broad Line Region

    Energy Technology Data Exchange (ETDEWEB)

    Czerny, Bozena [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Li, Yan-Rong [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Sredzinska, Justyna; Hryniewicz, Krzysztof [Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Panda, Swayam [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Wildy, Conor [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Karas, Vladimir, E-mail: bcz@cft.edu.pl [Astronomical Institute, Czech Academy of Sciences, Prague (Czech Republic)

    2017-06-22

    We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency) and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.

  14. Problem-solving and learning in Carib grackles: individuals show a consistent speed-accuracy trade-off.

    Science.gov (United States)

    Ducatez, S; Audet, J N; Lefebvre, L

    2015-03-01

    The generation and maintenance of within-population variation in cognitive abilities remain poorly understood. Recent theories propose that this variation might reflect the existence of consistent cognitive strategies distributed along a slow-fast continuum influenced by shyness. The slow-fast continuum might be reflected in the well-known speed-accuracy trade-off, where animals cannot simultaneously maximise the speed and the accuracy with which they perform a task. We test this idea on 49 wild-caught Carib grackles (Quiscalus lugubris), a tame opportunistic generalist Icterid bird in Barbados. Grackles that are fast at solving novel problems involving obstacle removal to reach visible food perform consistently over two different tasks, spend more time per trial attending to both tasks, and are those that show more shyness in a pretest. However, they are also the individuals that make more errors in a colour discrimination task requiring no new motor act. Our data reconcile some of the mixed positive and negative correlations reported in the comparative literature on cognitive tasks, suggesting that a speed-accuracy trade-off could lead to negative correlations between tasks favouring speed and tasks favouring accuracy, but still reveal consistent strategies based on stable individual differences.

  15. Modeling a Consistent Behavior of PLC-Sensors

    Directory of Open Access Journals (Sweden)

    E. V. Kuzmin

    2014-01-01

    Full Text Available The article extends the cycle of papers dedicated to programming and verificatoin of PLC-programs by LTL-specification. This approach provides the availability of correctness analysis of PLC-programs by the model checking method.The model checking method needs to construct a finite model of a PLC program. For successful verification of required properties it is important to take into consideration that not all combinations of input signals from the sensors can occur while PLC works with a control object. This fact requires more advertence to the construction of the PLC-program model.In this paper we propose to describe a consistent behavior of sensors by three groups of LTL-formulas. They will affect the program model, approximating it to the actual behavior of the PLC program. The idea of LTL-requirements is shown by an example.A PLC program is a description of reactions on input signals from sensors, switches and buttons. In constructing a PLC-program model, the approach to modeling a consistent behavior of PLC sensors allows to focus on modeling precisely these reactions without an extension of the program model by additional structures for realization of a realistic behavior of sensors. The consistent behavior of sensors is taken into account only at the stage of checking a conformity of the programming model to required properties, i. e. a property satisfaction proof for the constructed model occurs with the condition that the model contains only such executions of the program that comply with the consistent behavior of sensors.

  16. Consistent partnership formation: application to a sexually transmitted disease model.

    Science.gov (United States)

    Artzrouni, Marc; Deuchert, Eva

    2012-02-01

    We apply a consistent sexual partnership formation model which hinges on the assumption that one gender's choices drives the process (male or female dominant model). The other gender's behavior is imputed. The model is fitted to UK sexual behavior data and applied to a simple incidence model of HSV-2. With a male dominant model (which assumes accurate male reports on numbers of partners) the modeled incidences of HSV-2 are 77% higher for men and 50% higher for women than with a female dominant model (which assumes accurate female reports). Although highly stylized, our simple incidence model sheds light on the inconsistent results one can obtain with misreported data on sexual activity and age preferences. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Consistent estimation of linear panel data models with measurement error

    NARCIS (Netherlands)

    Meijer, Erik; Spierdijk, Laura; Wansbeek, Thomas

    2017-01-01

    Measurement error causes a bias towards zero when estimating a panel data linear regression model. The panel data context offers various opportunities to derive instrumental variables allowing for consistent estimation. We consider three sources of moment conditions: (i) restrictions on the

  18. Final Report Fermionic Symmetries and Self consistent Shell Model

    International Nuclear Information System (INIS)

    Zamick, Larry

    2008-01-01

    In this final report in the field of theoretical nuclear physics we note important accomplishments.We were confronted with 'anomoulous' magnetic moments by the experimetalists and were able to expain them. We found unexpected partial dynamical symmetries--completely unknown before, and were able to a large extent to expain them. The importance of a self consistent shell model was emphasized.

  19. Consistency checks in beam emission modeling for neutral beam injectors

    International Nuclear Information System (INIS)

    Punyapu, Bharathi; Vattipalle, Prahlad; Sharma, Sanjeev Kumar; Baruah, Ujjwal Kumar; Crowley, Brendan

    2015-01-01

    In positive neutral beam systems, the beam parameters such as ion species fractions, power fractions and beam divergence are routinely measured using Doppler shifted beam emission spectrum. The accuracy with which these parameters are estimated depend on the accuracy of the atomic modeling involved in these estimations. In this work, an effective procedure to check the consistency of the beam emission modeling in neutral beam injectors is proposed. As a first consistency check, at a constant beam voltage and current, the intensity of the beam emission spectrum is measured by varying the pressure in the neutralizer. Then, the scaling of measured intensity of un-shifted (target) and Doppler shifted intensities (projectile) of the beam emission spectrum at these pressure values are studied. If the un-shifted component scales with pressure, then the intensity of this component will be used as a second consistency check on the beam emission modeling. As a further check, the modeled beam fractions and emission cross sections of projectile and target are used to predict the intensity of the un-shifted component and then compared with the value of measured target intensity. An agreement between the predicted and measured target intensities provide the degree of discrepancy in the beam emission modeling. In order to test this methodology, a systematic analysis of Doppler shift spectroscopy data obtained on the JET neutral beam test stand data was carried out

  20. Follow-up study in local allergic rhinitis shows a consistent entity not evolving to systemic allergic rhinitis.

    Science.gov (United States)

    Rondón, Carmen; Campo, Paloma; Zambonino, Maria Angeles; Blanca-Lopez, Natalia; Torres, Maria J; Melendez, Lidia; Herrera, Rocio; Guéant-Rodriguez, Rosa-Maria; Guéant, Jean-Louis; Canto, Gabriela; Blanca, Miguel

    2014-04-01

    Local allergic rhinitis (LAR) is a common disease that affects 25.7% of the rhinitis population and more than 47% of patients previously diagnosed with nonallergic rhinitis. Whether LAR is the first step in the natural history of allergic rhinitis (AR) with systemic atopy or a consistent entity is unknown. The aim was to evaluate the natural history of a population with LAR of recent onset and the development of AR and asthma. A prospective 10-year follow-up study with initial cohorts of 194 patients with LAR of recent onset and 130 healthy controls is being undertaken. A clinical-demographic questionnaire, spirometry, skin prick test, and specific IgE to aeroallergens were done yearly. Nasal allergen provocation tests with Dermatophagoides pteronyssinus, Alternaria alternata, Olea europea, and a mix of grass pollen were performed at baseline and after 5 years. At disease onset, most of the patients with LAR had moderate-to-severe persistent-perennial rhinitis; conjunctivitis and asthma were the main comorbidities (51.1% and 18.8%, respectively), and D pteronyssinus was the most relevant aeroallergen (51.1%). After 5 years of follow-up, a worsening of rhinitis was detected in 26.2%, with an increase in symptom persistence and severity, and new associations with conjunctivitis and asthma. Atopy was detected by skin prick test and/or serum specific-IgE in patients with LAR (6.81%) and in controls (4.5%). This study shows a similar rate of development of systemic atopy in LAR and controls, which suggests that LAR is an entity well differentiated from AR. To determine the natural course of LAR more precisely, this study is in progress to complete 10 years of follow-up. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

  1. Structure and internal consistency of a shoulder model.

    Science.gov (United States)

    Högfors, C; Karlsson, D; Peterson, B

    1995-07-01

    A three-dimensional biomechanical model of the shoulder is developed for force predictions in 46 shoulder structures. The model is directed towards the analysis of static working situations where the load is low or moderate. Arbitrary static arm postures in the natural shoulder range may be considered, as well as different kinds of external loads including different force and moment directions. The model can predict internal forces for the shoulder muscles, for the glenohumeral, the acromioclavicular and the sternoclavicular joint as well as for the coracohumeral ligament. A solution to the statistically indeterminate force system is obtained by minimising an objective function. The default function chosen for this is the sum of the squared muscle stresses, but other objective functions may be used as well. The structure of the model is described and its ingredients discussed. The internal consistency of the model, its structural stability and the compatibility of the elements that go into it, is investigated.

  2. Consistency Across Standards or Standards in a New Business Model

    Science.gov (United States)

    Russo, Dane M.

    2010-01-01

    Presentation topics include: standards in a changing business model, the new National Space Policy is driving change, a new paradigm for human spaceflight, consistency across standards, the purpose of standards, danger of over-prescriptive standards, a balance is needed (between prescriptive and general standards), enabling versus inhibiting, characteristics of success-oriented standards, characteristics of success-oriented standards, and conclusions. Additional slides include NASA Procedural Requirements 8705.2B identifies human rating standards and requirements, draft health and medical standards for human rating, what's been done, government oversight models, examples of consistency from anthropometry, examples of inconsistency from air quality and appendices of government and non-governmental human factors standards.

  3. A Self-consistent Model of the Solar Tachocline

    Science.gov (United States)

    Wood, T. S.; Brummell, N. H.

    2018-02-01

    We present a local but fully nonlinear model of the solar tachocline, using three-dimensional direct numerical simulations. The tachocline forms naturally as a statistically steady balance between Coriolis, pressure, buoyancy, and Lorentz forces beneath a turbulent convection zone. Uniform rotation is maintained in the radiation zone by a primordial magnetic field, which is confined by meridional flows in the tachocline and convection zone. Such balanced dynamics has previously been found in idealized laminar models, but never in fully self-consistent numerical simulations.

  4. A Consistent Pricing Model for Index Options and Volatility Derivatives

    DEFF Research Database (Denmark)

    Kokholm, Thomas

    We propose a flexible modeling framework for the joint dynamics of an index and a set of forward variance swap rates written on this index. Our model reproduces various empirically observed properties of variance swap dynamics and enables volatility derivatives and options on the underlying index...... on the underlying asset. The model has the convenient feature of decoupling the vanilla skews from spot/volatility correlations and allowing for different conditional correlations in large and small spot/volatility moves. We show that our model can simultaneously fit prices of European options on S&P 500 across...

  5. Large scale Bayesian nuclear data evaluation with consistent model defects

    International Nuclear Information System (INIS)

    Schnabel, G

    2015-01-01

    Monte Carlo sampling schemes of available evaluation methods. The second improvement concerns Bayesian evaluation methods based on a certain simplification of the nuclear model. These methods were restricted to the consistent evaluation of tens of thousands of observables. In this thesis, a new evaluation scheme has been developed, which is mathematically equivalent to existing methods, but allows the consistent evaluation of dozens of millions of observables. The new scheme is suited for the implementation as a database application. The realization of such an application with public access can help to accelerate the production of reliable nuclear data sets. Furthermore, in combination with the novel treatment of model deficiencies, problems of the model and the experimental data can be tracked down without user interaction. This feature can foster the development of nuclear models with high predictive power. (author) [de

  6. Self-consistent Modeling of Elastic Anisotropy in Shale

    Science.gov (United States)

    Kanitpanyacharoen, W.; Wenk, H.; Matthies, S.; Vasin, R.

    2012-12-01

    Elastic anisotropy in clay-rich sedimentary rocks has increasingly received attention because of significance for prospecting of petroleum deposits, as well as seals in the context of nuclear waste and CO2 sequestration. The orientation of component minerals and pores/fractures is a critical factor that influences elastic anisotropy. In this study, we investigate lattice and shape preferred orientation (LPO and SPO) of three shales from the North Sea in UK, the Qusaiba Formation in Saudi Arabia, and the Officer Basin in Australia (referred to as N1, Qu3, and L1905, respectively) to calculate elastic properties and compare them with experimental results. Synchrotron hard X-ray diffraction and microtomography experiments were performed to quantify LPO, weight proportions, and three-dimensional SPO of constituent minerals and pores. Our preliminary results show that the degree of LPO and total amount of clays are highest in Qu3 (3.3-6.5 m.r.d and 74vol%), moderately high in N1 (2.4-5.6 m.r.d. and 70vol%), and lowest in L1905 (2.3-2.5 m.r.d. and 42vol%). In addition, porosity in Qu3 is as low as 2% while it is up to 6% in L1605 and 8% in N1, respectively. Based on this information and single crystal elastic properties of mineral components, we apply a self-consistent averaging method to calculate macroscopic elastic properties and corresponding seismic velocities for different shales. The elastic model is then compared with measured acoustic velocities on the same samples. The P-wave velocities measured from Qu3 (4.1-5.3 km/s, 26.3%Ani.) are faster than those obtained from L1905 (3.9-4.7 km/s, 18.6%Ani.) and N1 (3.6-4.3 km/s, 17.7%Ani.). By making adjustments for pore structure (aspect ratio) and single crystal elastic properties of clay minerals, a good agreement between our calculation and the ultrasonic measurement is obtained.

  7. Mean-field theory and self-consistent dynamo modeling

    International Nuclear Information System (INIS)

    Yoshizawa, Akira; Yokoi, Nobumitsu

    2001-12-01

    Mean-field theory of dynamo is discussed with emphasis on the statistical formulation of turbulence effects on the magnetohydrodynamic equations and the construction of a self-consistent dynamo model. The dynamo mechanism is sought in the combination of the turbulent residual-helicity and cross-helicity effects. On the basis of this mechanism, discussions are made on the generation of planetary magnetic fields such as geomagnetic field and sunspots and on the occurrence of flow by magnetic fields in planetary and fusion phenomena. (author)

  8. Self-consistent modeling of amorphous silicon devices

    International Nuclear Information System (INIS)

    Hack, M.

    1987-01-01

    The authors developed a computer model to describe the steady-state behaviour of a range of amorphous silicon devices. It is based on the complete set of transport equations and takes into account the important role played by the continuous distribution of localized states in the mobility gap of amorphous silicon. Using one set of parameters they have been able to self-consistently simulate the current-voltage characteristics of p-i-n (or n-i-p) solar cells under illumination, the dark behaviour of field-effect transistors, p-i-n diodes and n-i-n diodes in both the ohmic and space charge limited regimes. This model also describes the steady-state photoconductivity of amorphous silicon, in particular, its dependence on temperature, doping and illumination intensity

  9. Mechanistically Consistent Reduced Models of Synthetic Gene Networks

    Science.gov (United States)

    Mier-y-Terán-Romero, Luis; Silber, Mary; Hatzimanikatis, Vassily

    2013-01-01

    Designing genetic networks with desired functionalities requires an accurate mathematical framework that accounts for the essential mechanistic details of the system. Here, we formulate a time-delay model of protein translation and mRNA degradation by systematically reducing a detailed mechanistic model that explicitly accounts for the ribosomal dynamics and the cleaving of mRNA by endonucleases. We exploit various technical and conceptual advantages that our time-delay model offers over the mechanistic model to probe the behavior of a self-repressing gene over wide regions of parameter space. We show that a heuristic time-delay model of protein synthesis of a commonly used form yields a notably different prediction for the parameter region where sustained oscillations occur. This suggests that such heuristics can lead to erroneous results. The functional forms that arise from our systematic reduction can be used for every system that involves transcription and translation and they could replace the commonly used heuristic time-delay models for these processes. The results from our analysis have important implications for the design of synthetic gene networks and stress that such design must be guided by a combination of heuristic models and mechanistic models that include all relevant details of the process. PMID:23663853

  10. Multi-taxa approach shows consistent shifts in arthropod functional traits along grassland land-use intensity gradient.

    Science.gov (United States)

    Simons, Nadja K; Weisser, Wolfgang W; Gossner, Martin M

    2016-03-01

    Intensification of land use reduces biodiversity but may also shift the trait composition of communities. Understanding how land use affects single traits and community trait composition, helps to understand why some species are more affected by land use than others. Trait-based analyses are common for plants, but rare for arthropods. We collected literature-based traits for nearly 1000 insect and spider species to test how land- use intensity (including mowing, fertilization, and grazing) across 124 grasslands in three regions of Germany affects community-weighted mean traits across taxa and in single taxa. We additionally measured morphometric traits for more than 150 Heteroptera species and tested whether the weighted mean morphometric traits change with increasing land-use intensity. Community average body size decreased and community average dispersal ability increased from low to high land-use intensity. Furthermore, the relative abundance of herbivores and of specialists among herbivores decreased and the relative abundance of species using the herb layer increased with increasing land-use intensity. Community-weighted means of the morphometric traits in Heteroptera also changed from low to high land-use intensity toward longer and thinner shapes as well as longer appendices (legs, wings, and antenna). While changes in traits with increasing mowing and fertilization intensity were consistent with the combined land-use intensity, community average traits did often not change or with opposite direction under increasing grazing intensity. We conclude that high land-use intensity acts as an environmental filter selecting for on average smaller, more mobile, and less specialized species across taxa. Although trait collection across multiple arthropod taxa is laborious and needs clear trait definitions, it is essential for understanding the functional consequences of biodiversity loss due to land-use intensification.

  11. Classical and Quantum Consistency of the DGP Model

    CERN Document Server

    Nicolis, A; Nicolis, Alberto; Rattazzi, Riccardo

    2004-01-01

    We study the Dvali-Gabadadze-Porrati model by the method of the boundary effective action. The truncation of this action to the bending mode \\pi consistently describes physics in a wide range of regimes both at the classical and at the quantum level. The Vainshtein effect, which restores agreement with precise tests of general relativity, follows straightforwardly. We give a simple and general proof of stability, i.e. absence of ghosts in the fluctuations, valid for most of the relevant cases, like for instance the spherical source in asymptotically flat space. However we confirm that around certain interesting self-accelerating cosmological solutions there is a ghost. We consider the issue of quantum corrections. Around flat space \\pi becomes strongly coupled below a macroscopic length of 1000 km, thus impairing the predictivity of the model. Indeed the tower of higher dimensional operators which is expected by a generic UV completion of the model limits predictivity at even larger length scales. We outline ...

  12. The Work Role Functioning Questionnaire v2.0 Showed Consistent Factor Structure Across Six Working Samples

    DEFF Research Database (Denmark)

    Abma, Femke I.; Bültmann, Ute; Amick, Benjamin C.

    2017-01-01

    Objective: The Work Role Functioning Questionnaire v2.0 (WRFQ) is an outcome measure linking a persons’ health to the ability to meet work demands in the twenty-first century. We aimed to examine the construct validity of the WRFQ in a heterogeneous set of working samples in the Netherlands...... with mixed clinical conditions and job types to evaluate the comparability of the scale structure. Methods: Confirmatory factor and multi-group analyses were conducted in six cross-sectional working samples (total N = 2433) to evaluate and compare a five-factor model structure of the WRFQ (work scheduling....... Therefore subscale scores are recommended to compare across different clinical and working samples....

  13. Thermodynamically consistent mesoscopic model of the ferro/paramagnetic transition

    Czech Academy of Sciences Publication Activity Database

    Benešová, Barbora; Kružík, Martin; Roubíček, Tomáš

    2013-01-01

    Roč. 64, Č. 1 (2013), s. 1-28 ISSN 0044-2275 R&D Projects: GA AV ČR IAA100750802; GA ČR GA106/09/1573; GA ČR GAP201/10/0357 Grant - others:GA ČR(CZ) GA106/08/1397; GA MŠk(CZ) LC06052 Program:GA; LC Institutional support: RVO:67985556 Keywords : ferro-para-magnetism * evolution * thermodynamics Subject RIV: BA - General Mathematics; BA - General Mathematics (UT-L) Impact factor: 1.214, year: 2013 http://library.utia.cas.cz/separaty/2012/MTR/kruzik-thermodynamically consistent mesoscopic model of the ferro-paramagnetic transition.pdf

  14. A CVAR scenario for a standard monetary model using theory-consistent expectations

    DEFF Research Database (Denmark)

    Juselius, Katarina

    2017-01-01

    A theory-consistent CVAR scenario describes a set of testable regularities capturing basic assumptions of the theoretical model. Using this concept, the paper considers a standard model for exchange rate determination and shows that all assumptions about the model's shock structure and steady...

  15. Consistent model reduction of polymer chains in solution in dissipative particle dynamics: Model description

    KAUST Repository

    Moreno Chaparro, Nicolas

    2015-06-30

    We introduce a framework for model reduction of polymer chain models for dissipative particle dynamics (DPD) simulations, where the properties governing the phase equilibria such as the characteristic size of the chain, compressibility, density, and temperature are preserved. The proposed methodology reduces the number of degrees of freedom required in traditional DPD representations to model equilibrium properties of systems with complex molecules (e.g., linear polymers). Based on geometrical considerations we explicitly account for the correlation between beads in fine-grained DPD models and consistently represent the effect of these correlations in a reduced model, in a practical and simple fashion via power laws and the consistent scaling of the simulation parameters. In order to satisfy the geometrical constraints in the reduced model we introduce bond-angle potentials that account for the changes in the chain free energy after the model reduction. Following this coarse-graining process we represent high molecular weight DPD chains (i.e., ≥200≥200 beads per chain) with a significant reduction in the number of particles required (i.e., ≥20≥20 times the original system). We show that our methodology has potential applications modeling systems of high molecular weight molecules at large scales, such as diblock copolymer and DNA.

  16. On the internal consistency of holographic dark energy models

    International Nuclear Information System (INIS)

    Horvat, R

    2008-01-01

    Holographic dark energy (HDE) models, underpinned by an effective quantum field theory (QFT) with a manifest UV/IR connection, have become convincing candidates for providing an explanation of the dark energy in the universe. On the other hand, the maximum number of quantum states that a conventional QFT for a box of size L is capable of describing relates to those boxes which are on the brink of experiencing a sudden collapse to a black hole. Another restriction on the underlying QFT is that the UV cut-off, which cannot be chosen independently of the IR cut-off and therefore becomes a function of time in a cosmological setting, should stay the largest energy scale even in the standard cosmological epochs preceding a dark energy dominated one. We show that, irrespective of whether one deals with the saturated form of HDE or takes a certain degree of non-saturation in the past, the above restrictions cannot be met in a radiation dominated universe, an epoch in the history of the universe which is expected to be perfectly describable within conventional QFT

  17. Self-consistent approach for neutral community models with speciation

    NARCIS (Netherlands)

    Haegeman, Bart; Etienne, Rampal S.

    Hubbell's neutral model provides a rich theoretical framework to study ecological communities. By incorporating both ecological and evolutionary time scales, it allows us to investigate how communities are shaped by speciation processes. The speciation model in the basic neutral model is

  18. Self-consistent modelling of resonant tunnelling structures

    DEFF Research Database (Denmark)

    Fiig, T.; Jauho, A.P.

    1992-01-01

    We report a comprehensive study of the effects of self-consistency on the I-V-characteristics of resonant tunnelling structures. The calculational method is based on a simultaneous solution of the effective-mass Schrödinger equation and the Poisson equation, and the current is evaluated...

  19. Reconstruction of Consistent 3d CAD Models from Point Cloud Data Using a Priori CAD Models

    Science.gov (United States)

    Bey, A.; Chaine, R.; Marc, R.; Thibault, G.; Akkouche, S.

    2011-09-01

    We address the reconstruction of 3D CAD models from point cloud data acquired in industrial environments, using a pre-existing 3D model as an initial estimate of the scene to be processed. Indeed, this prior knowledge can be used to drive the reconstruction so as to generate an accurate 3D model matching the point cloud. We more particularly focus our work on the cylindrical parts of the 3D models. We propose to state the problem in a probabilistic framework: we have to search for the 3D model which maximizes some probability taking several constraints into account, such as the relevancy with respect to the point cloud and the a priori 3D model, and the consistency of the reconstructed model. The resulting optimization problem can then be handled using a stochastic exploration of the solution space, based on the random insertion of elements in the configuration under construction, coupled with a greedy management of the conflicts which efficiently improves the configuration at each step. We show that this approach provides reliable reconstructed 3D models by presenting some results on industrial data sets.

  20. Consistency between 2D-3D Sediment Transport models

    Science.gov (United States)

    Villaret, Catherine; Jodeau, Magali

    2017-04-01

    Sediment transport models have been developed and applied by the engineering community to estimate transport rates and morphodynamic bed evolutions in river flows, coastal and estuarine conditions. Environmental modelling systems like the open-source Telemac modelling system include a hierarchy of models from 1D (Mascaret), 2D (Telemac-2D/Sisyphe) and 3D (Telemac-3D/Sedi-3D) and include a wide range of processes to represent sediment flow interactions under more and more complex situations (cohesive, non-cohesive and mixed sediment). Despite some tremendous progresses in the numerical techniques and computing resources, the quality/accuracy of model results mainly depend on the numerous choices and skills of the modeler. In complex situations involving stratification effects, complex geometry, recirculating flows… 2D model assumptions are no longer valid. A full 3D turbulent flow model is then required in order to capture the vertical mixing processes and to represent accurately the coupled flow/sediment distribution. However a number of theoretical and numerical difficulties arise when dealing with sediment transport modelling in 3D which will be high-lighted : (1) Dependency of model results to the vertical grid refinement and choice of boundary conditions and numerical scheme (2) The choice of turbulence model determines also the sediment vertical distribution which is governed by a balance between the downward settling term and upward turbulent diffusion. (3) The use of different numerical schemes for both hydrodynamics (mean and turbulent flow) and sediment transport modelling can lead to some inconsistency including a mismatch in the definition of numerical cells and definition of boundary conditions. We discuss here those present issues and present some detailed comparison between 2D and 3D simulations on a set of validation test cases which are available in the Telemac 7.2 release using both cohesive and non-cohesive sediments.

  1. Self-consistent assessment of Englert-Schwinger model on atomic properties.

    Science.gov (United States)

    Lehtomäki, Jouko; Lopez-Acevedo, Olga

    2017-12-21

    Our manuscript investigates a self-consistent solution of the statistical atom model proposed by Berthold-Georg Englert and Julian Schwinger (the ES model) and benchmarks it against atomic Kohn-Sham and two orbital-free models of the Thomas-Fermi-Dirac (TFD)-λvW family. Results show that the ES model generally offers the same accuracy as the well-known TFD-15vW model; however, the ES model corrects the failure in the Pauli potential near-nucleus region. We also point to the inability of describing low-Z atoms as the foremost concern in improving the present model.

  2. Is the island universe model consistent with observations?

    OpenAIRE

    Piao, Yun-Song

    2005-01-01

    We study the island universe model, in which initially the universe is in a cosmological constant sea, then the local quantum fluctuations violating the null energy condition create the islands of matter, some of which might corresponds to our observable universe. We examine the possibility that the island universe model is regarded as an alternative scenario of the origin of observable universe.

  3. Thermodynamically consistent description of criticality in models of correlated electrons

    Czech Academy of Sciences Publication Activity Database

    Janiš, Václav; Kauch, Anna; Pokorný, Vladislav

    2017-01-01

    Roč. 95, č. 4 (2017), s. 1-14, č. článku 045108. ISSN 2469-9950 R&D Projects: GA ČR GA15-14259S Institutional support: RVO:68378271 Keywords : conserving approximations * Anderson model * Hubbard model * parquet equations Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016

  4. Towards a self-consistent dynamical nuclear model

    International Nuclear Information System (INIS)

    Roca-Maza, X; Colò, G; Bortignon, P F; Niu, Y F

    2017-01-01

    Density functional theory (DFT) is a powerful and accurate tool, exploited in nuclear physics to investigate the ground-state and some of the collective properties of nuclei along the whole nuclear chart. Models based on DFT are not, however, suitable for the description of single-particle dynamics in nuclei. Following the field theoretical approach by A Bohr and B R Mottelson to describe nuclear interactions between single-particle and vibrational degrees of freedom, we have taken important steps towards the building of a microscopic dynamic nuclear model. In connection with this, one important issue that needs to be better understood is the renormalization of the effective interaction in the particle-vibration approach. One possible way to renormalize the interaction is by the so-called subtraction method . In this contribution, we will implement the subtraction method in our model for the first time and study its consequences. (paper)

  5. Adjoint-consistent formulations of slip models for coupled electroosmotic flow systems

    KAUST Repository

    Garg, Vikram V

    2014-09-27

    Background Models based on the Helmholtz `slip\\' approximation are often used for the simulation of electroosmotic flows. The objectives of this paper are to construct adjoint-consistent formulations of such models, and to develop adjoint-based numerical tools for adaptive mesh refinement and parameter sensitivity analysis. Methods We show that the direct formulation of the `slip\\' model is adjoint inconsistent, and leads to an ill-posed adjoint problem. We propose a modified formulation of the coupled `slip\\' model, which is shown to be well-posed, and therefore automatically adjoint-consistent. Results Numerical examples are presented to illustrate the computation and use of the adjoint solution in two-dimensional microfluidics problems. Conclusions An adjoint-consistent formulation for Helmholtz `slip\\' models of electroosmotic flows has been proposed. This formulation provides adjoint solutions that can be reliably used for mesh refinement and sensitivity analysis.

  6. A thermodynamically consistent model of shape-memory alloys

    Czech Academy of Sciences Publication Activity Database

    Benešová, Barbora

    2011-01-01

    Roč. 11, č. 1 (2011), s. 355-356 ISSN 1617-7061 R&D Projects: GA ČR GAP201/10/0357 Institutional research plan: CEZ:AV0Z20760514 Keywords : slape memory alloys * model based on relaxation * thermomechanic coupling Subject RIV: BA - General Mathematics http://onlinelibrary.wiley.com/doi/10.1002/pamm.201110169/abstract

  7. On self-consistent N=1 supersymmetric composite models

    International Nuclear Information System (INIS)

    Pirogov, Yu.F.

    1984-01-01

    A class of fermion-boson N=1 supersymmetric composite models is considered. The models satisfy the anomaly matching condition, n-independence and the survival hypothesis. A unique admissible set of light states has been found under additional requirements for the two-particle metacolour force saturation, left-right discrete symmetry and observability of spectator states, on a par with the composite ones, the formey being necessary to compensate for axial anomalies. With respect to the unbroken chiral symmetry Gsup((MF))=SU(n)sub(L)xSU(n)sub(R), the light set has in left-chiral notations the form [(n(n-1)/2, 1)+(1, anti n(n-1)/2]+2(anti n, n)+[(n(n+1)/2/, 1)+(1, anti n(n-1)/2] independent of the metacolo group Gsup((MC)). The effective interaction theory for the light set on the mass scales, smaller than that of compositeness, is the N=1 supersymmetric grand unified model Gsup((MF))=SU(n)sub(L)xSU(n)sub(R). Here n=6, 8 are phenomenologically acceptable. On low mass scales, the light set transforms exactly into four families of ordinary leptons and quarks. In accordance with the survival hypothesis, all exotic states are naturally heavy under the spontaneous breaking of Gsup((MF)) to the low-energy standard model symmetry

  8. A seismologically consistent compositional model of Earth's core.

    Science.gov (United States)

    Badro, James; Côté, Alexander S; Brodholt, John P

    2014-05-27

    Earth's core is less dense than iron, and therefore it must contain "light elements," such as S, Si, O, or C. We use ab initio molecular dynamics to calculate the density and bulk sound velocity in liquid metal alloys at the pressure and temperature conditions of Earth's outer core. We compare the velocity and density for any composition in the (Fe-Ni, C, O, Si, S) system to radial seismological models and find a range of compositional models that fit the seismological data. We find no oxygen-free composition that fits the seismological data, and therefore our results indicate that oxygen is always required in the outer core. An oxygen-rich core is a strong indication of high-pressure and high-temperature conditions of core differentiation in a deep magma ocean with an FeO concentration (oxygen fugacity) higher than that of the present-day mantle.

  9. Flood damage: a model for consistent, complete and multipurpose scenarios

    Science.gov (United States)

    Menoni, Scira; Molinari, Daniela; Ballio, Francesco; Minucci, Guido; Mejri, Ouejdane; Atun, Funda; Berni, Nicola; Pandolfo, Claudia

    2016-12-01

    Effective flood risk mitigation requires the impacts of flood events to be much better and more reliably known than is currently the case. Available post-flood damage assessments usually supply only a partial vision of the consequences of the floods as they typically respond to the specific needs of a particular stakeholder. Consequently, they generally focus (i) on particular items at risk, (ii) on a certain time window after the occurrence of the flood, (iii) on a specific scale of analysis or (iv) on the analysis of damage only, without an investigation of damage mechanisms and root causes. This paper responds to the necessity of a more integrated interpretation of flood events as the base to address the variety of needs arising after a disaster. In particular, a model is supplied to develop multipurpose complete event scenarios. The model organizes available information after the event according to five logical axes. This way post-flood damage assessments can be developed that (i) are multisectoral, (ii) consider physical as well as functional and systemic damage, (iii) address the spatial scales that are relevant for the event at stake depending on the type of damage that has to be analyzed, i.e., direct, functional and systemic, (iv) consider the temporal evolution of damage and finally (v) allow damage mechanisms and root causes to be understood. All the above features are key for the multi-usability of resulting flood scenarios. The model allows, on the one hand, the rationalization of efforts currently implemented in ex post damage assessments, also with the objective of better programming financial resources that will be needed for these types of events in the future. On the other hand, integrated interpretations of flood events are fundamental to adapting and optimizing flood mitigation strategies on the basis of thorough forensic investigation of each event, as corroborated by the implementation of the model in a case study.

  10. Toward a Self-Consistent Dynamical Model of the NSSL

    Science.gov (United States)

    Matilsky, Loren

    2018-01-01

    The advent of helioseismology has revealed in detail the internal differential rotation profile of the Sun. In particular, the presence of two boundary layers, the tachocline at the bottom of the convection zone (CZ) and the Near Surface Shear Layer (NSSL) at the top of the CZ, has remained a mystery. These two boundary layers may have significant consequences for the internal dynamo that operates the Sun's magnetic field, and so understanding their dynamics is an important step in solar physics and in the theory of solar-like stellar structure in general. In this talk, we analyze three numerical models of hydrodynamic convection in rotating spherical shells with varying degrees of stratification in order to understand the dynamical balance of the solar near-surface shear layer (NSSL). We find that with sufficient stratification, a boundary layer with some characteristics of the NSSL develops at high latitudes, and it is maintained purely an inertial balance of torques in which the viscosity is negligible. An inward radial flux of angular momentum from the Reynold's stress (as has been predicted by theory) is balanced by the poleward latitudinal flux of angular momentum due to the meridional circulation. We analyze the similarities of the near surface shear in our models to that of the Sun, and find that the solar NSSL is most likely maintained by the inertial balance our simulations display at high latitudes, but with a modified upper boundary condition.

  11. Consistency problems for Heath-Jarrow-Morton interest rate models

    CERN Document Server

    Filipović, Damir

    2001-01-01

    The book is written for a reader with knowledge in mathematical finance (in particular interest rate theory) and elementary stochastic analysis, such as provided by Revuz and Yor (Continuous Martingales and Brownian Motion, Springer 1991). It gives a short introduction both to interest rate theory and to stochastic equations in infinite dimension. The main topic is the Heath-Jarrow-Morton (HJM) methodology for the modelling of interest rates. Experts in SDE in infinite dimension with interest in applications will find here the rigorous derivation of the popular "Musiela equation" (referred to in the book as HJMM equation). The convenient interpretation of the classical HJM set-up (with all the no-arbitrage considerations) within the semigroup framework of Da Prato and Zabczyk (Stochastic Equations in Infinite Dimensions) is provided. One of the principal objectives of the author is the characterization of finite-dimensional invariant manifolds, an issue that turns out to be vital for applications. Finally, ge...

  12. A WFS1 haplotype consisting of the minor alleles of rs752854, rs10010131, and rs734312 shows a protective role against type 2 diabetes in Russian patients.

    Science.gov (United States)

    Chistiakov, Dimitry A; Khodyrev, Dmitry S; Smetanina, Svetlana A; Bel'chikova, Larisa N; Suplotova, Lyudmila A; Nosikov, Valery V

    2010-01-01

    Rare variants of the WFS1 gene encoding wolframin cause Wolfram syndrome, a monogenic disease associated with diabetes insipidus, diabetes mellitus, optic atrophy, and deafness. In contrast, common variants of WFS1 showed association with type 2 diabetes (T2D) in numerous Caucasian populations. In this study, we tested whether the markers rs752854, rs10010131, and rs734312, located in the WFS1 gene, are related to the development of T2D in a Russian population. The polymorphic markers were genotyped in Russian diabetic (n = 1,112) and non-diabetic (n = 1,097) patients using a Taqman allele discrimination assay. The correlation between the carriage of disease-associated WFS1 variants and the patients' clinical and metabolic characteristics was studied using ANOVA and ANCOVA. Adjustment for confounding variables such as gender, age, body mass index, obesity, HbA1c, and hypertension was made. Haplotype GAG, consisting of the minor alleles of rs752854, rs10010131, and rs734312, respectively, showed association with decreased risk of T2D (OR = 0.44, 95% CI = 0.32-0.61, p = 4.3 x 10(-7)). Compared to other WFS1 variants, non-diabetic individuals homozygous for GAG/CAG had significantly increased fasting insulin (p(adjusted) = 0.047) and homeostasis model assessment of β-cell function (HOMA-β) index (p(adjusted) = 0.006). Diabetic patients homozygous for GAG/GAG showed significantly elevated levels of 2-h insulin (p(adjusted) = 0.029) and HOMA-β = 0.011. Disease-associated variants of WFS1 contribute to the pathogenesis of T2D through impaired insulin response to glucose stimulation and altered β-cell function.

  13. A non-parametric consistency test of the ΛCDM model with Planck CMB data

    Energy Technology Data Exchange (ETDEWEB)

    Aghamousa, Amir; Shafieloo, Arman [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Hamann, Jan, E-mail: amir@aghamousa.com, E-mail: jan.hamann@unsw.edu.au, E-mail: shafieloo@kasi.re.kr [School of Physics, The University of New South Wales, Sydney NSW 2052 (Australia)

    2017-09-01

    Non-parametric reconstruction methods, such as Gaussian process (GP) regression, provide a model-independent way of estimating an underlying function and its uncertainty from noisy data. We demonstrate how GP-reconstruction can be used as a consistency test between a given data set and a specific model by looking for structures in the residuals of the data with respect to the model's best-fit. Applying this formalism to the Planck temperature and polarisation power spectrum measurements, we test their global consistency with the predictions of the base ΛCDM model. Our results do not show any serious inconsistencies, lending further support to the interpretation of the base ΛCDM model as cosmology's gold standard.

  14. Development of a Model for Dynamic Recrystallization Consistent with the Second Derivative Criterion

    Directory of Open Access Journals (Sweden)

    Muhammad Imran

    2017-11-01

    Full Text Available Dynamic recrystallization (DRX processes are widely used in industrial hot working operations, not only to keep the forming forces low but also to control the microstructure and final properties of the workpiece. According to the second derivative criterion (SDC by Poliak and Jonas, the onset of DRX can be detected from an inflection point in the strain-hardening rate as a function of flow stress. Various models are available that can predict the evolution of flow stress from incipient plastic flow up to steady-state deformation in the presence of DRX. Some of these models have been implemented into finite element codes and are widely used for the design of metal forming processes, but their consistency with the SDC has not been investigated. This work identifies three sources of inconsistencies that models for DRX may exhibit. For a consistent modeling of the DRX kinetics, a new strain-hardening model for the hardening stages III to IV is proposed and combined with consistent recrystallization kinetics. The model is devised in the Kocks-Mecking space based on characteristic transition in the strain-hardening rate. A linear variation of the transition and inflection points is observed for alloy 800H at all tested temperatures and strain rates. The comparison of experimental and model results shows that the model is able to follow the course of the strain-hardening rate very precisely, such that highly accurate flow stress predictions are obtained.

  15. Development of a Model for Dynamic Recrystallization Consistent with the Second Derivative Criterion.

    Science.gov (United States)

    Imran, Muhammad; Kühbach, Markus; Roters, Franz; Bambach, Markus

    2017-11-02

    Dynamic recrystallization (DRX) processes are widely used in industrial hot working operations, not only to keep the forming forces low but also to control the microstructure and final properties of the workpiece. According to the second derivative criterion (SDC) by Poliak and Jonas, the onset of DRX can be detected from an inflection point in the strain-hardening rate as a function of flow stress. Various models are available that can predict the evolution of flow stress from incipient plastic flow up to steady-state deformation in the presence of DRX. Some of these models have been implemented into finite element codes and are widely used for the design of metal forming processes, but their consistency with the SDC has not been investigated. This work identifies three sources of inconsistencies that models for DRX may exhibit. For a consistent modeling of the DRX kinetics, a new strain-hardening model for the hardening stages III to IV is proposed and combined with consistent recrystallization kinetics. The model is devised in the Kocks-Mecking space based on characteristic transition in the strain-hardening rate. A linear variation of the transition and inflection points is observed for alloy 800H at all tested temperatures and strain rates. The comparison of experimental and model results shows that the model is able to follow the course of the strain-hardening rate very precisely, such that highly accurate flow stress predictions are obtained.

  16. Consistency in Estimation and Model Selection of Dynamic Panel Data Models with Fixed Effects

    Directory of Open Access Journals (Sweden)

    Guangjie Li

    2015-07-01

    Full Text Available We examine the relationship between consistent parameter estimation and model selection for autoregressive panel data models with fixed effects. We find that the transformation of fixed effects proposed by Lancaster (2002 does not necessarily lead to consistent estimation of common parameters when some true exogenous regressors are excluded. We propose a data dependent way to specify the prior of the autoregressive coefficient and argue for comparing different model specifications before parameter estimation. Model selection properties of Bayes factors and Bayesian information criterion (BIC are investigated. When model uncertainty is substantial, we recommend the use of Bayesian Model Averaging to obtain point estimators with lower root mean squared errors (RMSE. We also study the implications of different levels of inclusion probabilities by simulations.

  17. Self-consistency in the phonon space of the particle-phonon coupling model

    Science.gov (United States)

    Tselyaev, V.; Lyutorovich, N.; Speth, J.; Reinhard, P.-G.

    2018-04-01

    In the paper the nonlinear generalization of the time blocking approximation (TBA) is presented. The TBA is one of the versions of the extended random-phase approximation (RPA) developed within the Green-function method and the particle-phonon coupling model. In the generalized version of the TBA the self-consistency principle is extended onto the phonon space of the model. The numerical examples show that this nonlinear version of the TBA leads to the convergence of results with respect to enlarging the phonon space of the model.

  18. Alfven-wave particle interaction in finite-dimensional self-consistent field model

    International Nuclear Information System (INIS)

    Padhye, N.; Horton, W.

    1998-01-01

    A low-dimensional Hamiltonian model is derived for the acceleration of ions in finite amplitude Alfven waves in a finite pressure plasma sheet. The reduced low-dimensional wave-particle Hamiltonian is useful for describing the reaction of the accelerated ions on the wave amplitudes and phases through the self-consistent fields within the envelope approximation. As an example, the authors show for a single Alfven wave in the central plasma sheet of the Earth's geotail, modeled by the linear pinch geometry called the Harris sheet, the time variation of the wave amplitude during the acceleration of fast protons

  19. Self-consistent nonlinearly polarizable shell-model dynamics for ferroelectric materials

    International Nuclear Information System (INIS)

    Mkam Tchouobiap, S.E.; Kofane, T.C.; Ngabireng, C.M.

    2002-11-01

    We investigate the dynamical properties of the polarizable shellmodel with a symmetric double Morse-type electron-ion interaction in one ionic species. A variational calculation based on the Self-Consistent Einstein Model (SCEM) shows that a theoretical ferroelectric (FE) transition temperature can be derive which demonstrates the presence of a first-order phase transition for the potassium selenate (K 2 SeO 4 ) crystal around Tc 91.5 K. Comparison of the model calculation with the experimental critical temperature yields satisfactory agreement. (author)

  20. A new k-epsilon model consistent with Monin-Obukhov similarity theory

    DEFF Research Database (Denmark)

    van der Laan, Paul; Kelly, Mark C.; Sørensen, Niels N.

    2017-01-01

    A new k-" model is introduced that is consistent with Monin–Obukhov similarity theory (MOST). The proposed k-" model is compared with another k-" model that was developed in an attempt to maintain inlet profiles compatible with MOST. It is shown that the previous k-" model is not consistent with ...

  1. Consistent biases in Antarctic sea ice concentration simulated by climate models

    Science.gov (United States)

    Roach, Lettie A.; Dean, Samuel M.; Renwick, James A.

    2018-01-01

    The simulation of Antarctic sea ice in global climate models often does not agree with observations. In this study, we examine the compactness of sea ice, as well as the regional distribution of sea ice concentration, in climate models from the latest Coupled Model Intercomparison Project (CMIP5) and in satellite observations. We find substantial differences in concentration values between different sets of satellite observations, particularly at high concentrations, requiring careful treatment when comparing to models. As a fraction of total sea ice extent, models simulate too much loose, low-concentration sea ice cover throughout the year, and too little compact, high-concentration cover in the summer. In spite of the differences in physics between models, these tendencies are broadly consistent across the population of 40 CMIP5 simulations, a result not previously highlighted. Separating models with and without an explicit lateral melt term, we find that inclusion of lateral melt may account for overestimation of low-concentration cover. Targeted model experiments with a coupled ocean-sea ice model show that choice of constant floe diameter in the lateral melt scheme can also impact representation of loose ice. This suggests that current sea ice thermodynamics contribute to the inadequate simulation of the low-concentration regime in many models.

  2. Modeling Plankton Mixotrophy: A Mechanistic Model Consistent with the Shuter-Type Biochemical Approach

    Directory of Open Access Journals (Sweden)

    Caroline Ghyoot

    2017-07-01

    Full Text Available Mixotrophy, i.e., the ability to combine phototrophy and phagotrophy in one organism, is now recognized to be widespread among photic-zone protists and to potentially modify the structure and functioning of planktonic ecosystems. However, few biogeochemical/ecological models explicitly include this mode of nutrition, owing to the large diversity of observed mixotrophic types, the few data allowing the parameterization of physiological processes, and the need to make the addition of mixotrophy into existing ecosystem models as simple as possible. We here propose and discuss a flexible model that depicts the main observed behaviors of mixotrophy in microplankton. A first model version describes constitutive mixotrophy (the organism photosynthesizes by use of its own chloroplasts. This model version offers two possible configurations, allowing the description of constitutive mixotrophs (CMs that favor either phototrophy or heterotrophy. A second version describes non-constitutive mixotrophy (the organism performs phototrophy by use of chloroplasts acquired from its prey. The model variants were described so as to be consistent with a plankton conceptualization in which the biomass is divided into separate components on the basis of their biochemical function (Shuter-approach; Shuter, 1979. The two model variants of mixotrophy can easily be implemented in ecological models that adopt the Shuter-approach, such as the MIRO model (Lancelot et al., 2005, and address the challenges associated with modeling mixotrophy.

  3. Self-consistent multidimensional electron kinetic model for inductively coupled plasma sources

    Science.gov (United States)

    Dai, Fa Foster

    Inductively coupled plasma (ICP) sources have received increasing interest in microelectronics fabrication and lighting industry. In 2-D configuration space (r, z) and 2-D velocity domain (νθ,νz), a self- consistent electron kinetic analytic model is developed for various ICP sources. The electromagnetic (EM) model is established based on modal analysis, while the kinetic analysis gives the perturbed Maxwellian distribution of electrons by solving Boltzmann-Vlasov equation. The self- consistent algorithm combines the EM model and the kinetic analysis by updating their results consistently until the solution converges. The closed-form solutions in the analytical model provide rigorous and fast computing for the EM fields and the electron kinetic behavior. The kinetic analysis shows that the RF energy in an ICP source is extracted by a collisionless dissipation mechanism, if the electron thermovelocity is close to the RF phase velocities. A criterion for collisionless damping is thus given based on the analytic solutions. To achieve uniformly distributed plasma for plasma processing, we propose a novel discharge structure with both planar and vertical coil excitations. The theoretical results demonstrate improved uniformity for the excited azimuthal E-field in the chamber. Non-monotonic spatial decay in electric field and space current distributions was recently observed in weakly- collisional plasmas. The anomalous skin effect is found to be responsible for this phenomenon. The proposed model successfully models the non-monotonic spatial decay effect and achieves good agreements with the measurements for different applied RF powers. The proposed analytical model is compared with other theoretical models and different experimental measurements. The developed model is also applied to two kinds of ICP discharges used for electrodeless light sources. One structure uses a vertical internal coil antenna to excite plasmas and another has a metal shield to prevent the

  4. Traffic Multiresolution Modeling and Consistency Analysis of Urban Expressway Based on Asynchronous Integration Strategy

    Directory of Open Access Journals (Sweden)

    Liyan Zhang

    2017-01-01

    Full Text Available The paper studies multiresolution traffic flow simulation model of urban expressway. Firstly, compared with two-level hybrid model, three-level multiresolution hybrid model has been chosen. Then, multiresolution simulation framework and integration strategies are introduced. Thirdly, the paper proposes an urban expressway multiresolution traffic simulation model by asynchronous integration strategy based on Set Theory, which includes three submodels: macromodel, mesomodel, and micromodel. After that, the applicable conditions and derivation process of the three submodels are discussed in detail. In addition, in order to simulate and evaluate the multiresolution model, “simple simulation scenario” of North-South Elevated Expressway in Shanghai has been established. The simulation results showed the following. (1 Volume-density relationships of three submodels are unanimous with detector data. (2 When traffic density is high, macromodel has a high precision and smaller error and the dispersion of results is smaller. Compared with macromodel, simulation accuracies of micromodel and mesomodel are lower but errors are bigger. (3 Multiresolution model can simulate characteristics of traffic flow, capture traffic wave, and keep the consistency of traffic state transition. Finally, the results showed that the novel multiresolution model can have higher simulation accuracy and it is feasible and effective in the real traffic simulation scenario.

  5. A consistent modelling methodology for secondary settling tanks: a reliable numerical method.

    Science.gov (United States)

    Bürger, Raimund; Diehl, Stefan; Farås, Sebastian; Nopens, Ingmar; Torfs, Elena

    2013-01-01

    The consistent modelling methodology for secondary settling tanks (SSTs) leads to a partial differential equation (PDE) of nonlinear convection-diffusion type as a one-dimensional model for the solids concentration as a function of depth and time. This PDE includes a flux that depends discontinuously on spatial position modelling hindered settling and bulk flows, a singular source term describing the feed mechanism, a degenerating term accounting for sediment compressibility, and a dispersion term for turbulence. In addition, the solution itself is discontinuous. A consistent, reliable and robust numerical method that properly handles these difficulties is presented. Many constitutive relations for hindered settling, compression and dispersion can be used within the model, allowing the user to switch on and off effects of interest depending on the modelling goal as well as investigate the suitability of certain constitutive expressions. Simulations show the effect of the dispersion term on effluent suspended solids and total sludge mass in the SST. The focus is on correct implementation whereas calibration and validation are not pursued.

  6. Showing that the race model inequality is not violated

    DEFF Research Database (Denmark)

    Gondan, Matthias; Riehl, Verena; Blurton, Steven Paul

    2012-01-01

    When participants are asked to respond in the same way to stimuli from different sources (e. g., auditory and visual), responses are often observed to be substantially faster when both stimuli are presented simultaneously (redundancy gain). Different models account for this effect, the two most...

  7. Consistency Analysis of Genome-Scale Models of Bacterial Metabolism: A Metamodel Approach.

    Science.gov (United States)

    Ponce-de-Leon, Miguel; Calle-Espinosa, Jorge; Peretó, Juli; Montero, Francisco

    2015-01-01

    Genome-scale metabolic models usually contain inconsistencies that manifest as blocked reactions and gap metabolites. With the purpose to detect recurrent inconsistencies in metabolic models, a large-scale analysis was performed using a previously published dataset of 130 genome-scale models. The results showed that a large number of reactions (~22%) are blocked in all the models where they are present. To unravel the nature of such inconsistencies a metamodel was construed by joining the 130 models in a single network. This metamodel was manually curated using the unconnected modules approach, and then, it was used as a reference network to perform a gap-filling on each individual genome-scale model. Finally, a set of 36 models that had not been considered during the construction of the metamodel was used, as a proof of concept, to extend the metamodel with new biochemical information, and to assess its impact on gap-filling results. The analysis performed on the metamodel allowed to conclude: 1) the recurrent inconsistencies found in the models were already present in the metabolic database used during the reconstructions process; 2) the presence of inconsistencies in a metabolic database can be propagated to the reconstructed models; 3) there are reactions not manifested as blocked which are active as a consequence of some classes of artifacts, and; 4) the results of an automatic gap-filling are highly dependent on the consistency and completeness of the metamodel or metabolic database used as the reference network. In conclusion the consistency analysis should be applied to metabolic databases in order to detect and fill gaps as well as to detect and remove artifacts and redundant information.

  8. A Time consistent model for monetary value of man-sievert

    International Nuclear Information System (INIS)

    Na, S.H.; Kim, Sun G.

    2008-01-01

    Full text: Performing a cost-benefit analysis to establish optimum levels of radiation protection under the ALARA principle, we introduce a discrete stepwise model to evaluate man-sievert monetary value of Korea. The model formula, which is unique and country-specific, is composed of GDP, the nominal risk coefficient for cancer and hereditary effects, the aversion factor against radiation exposure, and the average life expectancy. Unlike previous researches on alpha-value assessment, we showed different alpha values optimized with respect to various ranges of individual dose, which would be more realistic and applicable to the radiation protection area. Employing economically constant term of GDP we showed the real values of man-sievert by year, which should be consistent in time series comparison even under price level fluctuation. GDP deflators of an economy have to be applied to measure one's own consistent value of radiation protection by year. In addition, we recommend that the concept of purchasing power parity should be adopted if it needs international comparison of alpha values in real terms. Finally, we explain the way that this stepwise model can be generalized simply to other countries without normalizing any country-specific factors. (author)

  9. A self-consistent model for thermodynamics of multicomponent solid solutions

    International Nuclear Information System (INIS)

    Svoboda, J.; Fischer, F.D.

    2016-01-01

    The self-consistent concept recently published in this journal (108, 27–30, 2015) is extended from a binary to a multicomponent system. This is possible by exploiting the trapping concept as basis for including the interaction of atoms in terms of pairs (e.g. A–A, B–B, C–C…) and couples (e.g. A–B, B–C, …) in a multicomponent system with A as solvent and B, C, … as dilute solutes. The model results in a formulation of Gibbs-energy, which can be minimized. Examples show that the couple and pair formation may influence the equilibrium Gibbs energy markedly.

  10. Possible world based consistency learning model for clustering and classifying uncertain data.

    Science.gov (United States)

    Liu, Han; Zhang, Xianchao; Zhang, Xiaotong

    2018-06-01

    Possible world has shown to be effective for handling various types of data uncertainty in uncertain data management. However, few uncertain data clustering and classification algorithms are proposed based on possible world. Moreover, existing possible world based algorithms suffer from the following issues: (1) they deal with each possible world independently and ignore the consistency principle across different possible worlds; (2) they require the extra post-processing procedure to obtain the final result, which causes that the effectiveness highly relies on the post-processing method and the efficiency is also not very good. In this paper, we propose a novel possible world based consistency learning model for uncertain data, which can be extended both for clustering and classifying uncertain data. This model utilizes the consistency principle to learn a consensus affinity matrix for uncertain data, which can make full use of the information across different possible worlds and then improve the clustering and classification performance. Meanwhile, this model imposes a new rank constraint on the Laplacian matrix of the consensus affinity matrix, thereby ensuring that the number of connected components in the consensus affinity matrix is exactly equal to the number of classes. This also means that the clustering and classification results can be directly obtained without any post-processing procedure. Furthermore, for the clustering and classification tasks, we respectively derive the efficient optimization methods to solve the proposed model. Experimental results on real benchmark datasets and real world uncertain datasets show that the proposed model outperforms the state-of-the-art uncertain data clustering and classification algorithms in effectiveness and performs competitively in efficiency. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. No consistent bioenergetic defects in presynaptic nerve terminals isolated from mouse models of Alzheimer's disease.

    Science.gov (United States)

    Choi, Sung W; Gerencser, Akos A; Ng, Ryan; Flynn, James M; Melov, Simon; Danielson, Steven R; Gibson, Bradford W; Nicholls, David G; Bredesen, Dale E; Brand, Martin D

    2012-11-21

    Depressed cortical energy supply and impaired synaptic function are predominant associations of Alzheimer's disease (AD). To test the hypothesis that presynaptic bioenergetic deficits are associated with the progression of AD pathogenesis, we compared bioenergetic variables of cortical and hippocampal presynaptic nerve terminals (synaptosomes) from commonly used mouse models with AD-like phenotypes (J20 age 6 months, Tg2576 age 16 months, and APP/PS age 9 and 14 months) to age-matched controls. No consistent bioenergetic deficiencies were detected in synaptosomes from the three models; only APP/PS cortical synaptosomes from 14-month-old mice showed an increase in respiration associated with proton leak. J20 mice were chosen for a highly stringent investigation of mitochondrial function and content. There were no significant differences in the quality of the synaptosomal preparations or the mitochondrial volume fraction. Furthermore, respiratory variables, calcium handling, and membrane potentials of synaptosomes from symptomatic J20 mice under calcium-imposed stress were not consistently impaired. The recovery of marker proteins during synaptosome preparation was the same, ruling out the possibility that the lack of functional bioenergetic defects in synaptosomes from J20 mice was due to the selective loss of damaged synaptosomes during sample preparation. Our results support the conclusion that the intrinsic bioenergetic capacities of presynaptic nerve terminals are maintained in these symptomatic AD mouse models.

  12. Towards a consistent geochemical model for prediction of uranium(VI) removal from groundwater by ferrihydrite

    International Nuclear Information System (INIS)

    Gustafsson, Jon Petter; Daessman, Ellinor; Baeckstroem, Mattias

    2009-01-01

    Uranium(VI), which is often elevated in granitoidic groundwaters, is known to adsorb strongly to Fe (hydr)oxides under certain conditions. This process can be used in water treatment to remove U(VI). To develop a consistent geochemical model for U(VI) adsorption to ferrihydrite, batch experiments were performed and previous data sets reviewed to optimize a set of surface complexation constants using the 3-plane CD-MUSIC model. To consider the effect of dissolved organic matter (DOM) on U(VI) speciation, new parameters for the Stockholm Humic Model (SHM) were optimized using previously published data. The model, which was constrained from available X-ray absorption fine structure (EXAFS) spectroscopy evidence, fitted the data well when the surface sites were divided into low- and high-affinity binding sites. Application of the model concept to other published data sets revealed differences in the reactivity of different ferrihydrites towards U(VI). Use of the optimized SHM parameters for U(VI)-DOM complexation showed that this process is important for U(VI) speciation at low pH. However in neutral to alkaline waters with substantial carbonate present, Ca-U-CO 3 complexes predominate. The calibrated geochemical model was used to simulate U(VI) adsorption to ferrihydrite for a hypothetical groundwater in the presence of several competitive ions. The results showed that U(VI) adsorption was strong between pH 5 and 8. Also near the calcite saturation limit, where U(VI) adsorption was weakest according to the model, the adsorption percentage was predicted to be >80%. Hence U(VI) adsorption to ferrihydrite-containing sorbents may be used as a method to bring down U(VI) concentrations to acceptable levels in groundwater

  13. Is biochemical relapse-free survival after profoundly hypofractionated radiotherapy consistent with current radiobiological models?

    Science.gov (United States)

    Tree, A C; Khoo, V S; van As, N J; Partridge, M

    2014-04-01

    The α/β ratio for prostate cancer is thought to be low and less than for the rectum, which is usually the dose-limiting organ. Hypofractionated radiotherapy should therefore improve the therapeutic ratio, increasing cure rates with less toxicity. A number of models for predicting biochemical relapse-free survival have been developed from large series of patients treated with conventional and moderately hypofractionated radiotherapy. The purpose of this study was to test these models when significant numbers of patients treated with profoundly hypofractionated radiotherapy were included. A systematic review of the literature with regard to hypofractionated radiotherapy for prostate cancer was conducted, focussing on data recently presented on prostate stereotactic body radiotherapy. For the work described here, we have taken published biochemical control rates for a range of moderately and profoundly fractionated schedules and plotted these together with a range of radiobiological models, which are described. The data reviewed show consistency between the various radiobiological model predictions and the currently observed data. Current radiobiological models provide accurate predictions of biochemical relapse-free survival, even when profoundly hypofractionated patients are included in the analysis. Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  14. Consistently modeling the same movement strategy is more important than model skill level in observational learning contexts.

    Science.gov (United States)

    Buchanan, John J; Dean, Noah

    2014-02-01

    The experiment undertaken was designed to elucidate the impact of model skill level on observational learning processes. The task was bimanual circle tracing with a 90° relative phase lead of one hand over the other hand. Observer groups watched videos of either an instruction model, a discovery model, or a skilled model. The instruction and skilled model always performed the task with the same movement strategy, the right-arm traced clockwise and the left-arm counterclockwise around circle templates with the right-arm leading. The discovery model used several movement strategies (tracing-direction/hand-lead) during practice. Observation of the instruction and skilled model provided a significant benefit compared to the discovery model when performing the 90° relative phase pattern in a post-observation test. The observers of the discovery model had significant room for improvement and benefited from post-observation practice of the 90° pattern. The benefit of a model is found in the consistency with which that model uses the same movement strategy, and not within the skill level of the model. It is the consistency in strategy modeled that allows observers to develop an abstract perceptual representation of the task that can be implemented into a coordinated action. Theoretically, the results show that movement strategy information (relative motion direction, hand lead) and relative phase information can be detected through visual perception processes and be successfully mapped to outgoing motor commands within an observational learning context. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Symmetry breaking in frustrated XY models: Results from new self-consistent fluctuation approach and simulations

    Science.gov (United States)

    Behzadi, Azad Esmailov

    1999-10-01

    The critical behavior of the fully frustrated XY model has remained controversial in spite of almost two decades of related research. In this study, we have developed a new method inspired by Netz and Berker's hard-spin mean- field theory. Our approach for XY models yields results consistent with Monte Carlo simulations as the ratio of antiferromagnetic to ferromagnetic interactions is varied. The method captures two phase transitions clearly separated in temperature for ratios of 0.5, 0.6, and 1.5, with these transitions moving closer together in temperature as the interaction ratio approaches 1.0, the fully frustrated case. From the system's chirality as a function of temperature in the critical region, we calculate the critical exponent β in agreement with an Ising transition for all of the interaction ratios studied, including 1.0. This result provides support for the view that there are two transitions, rather than one transition in a new universality class, occurring in the fully frustrated XY model. Finite size effects in this model can be essentially eliminated by rescaling the local magnetization, the quantity retained self- consistently in our computations. This rescaling scheme also shows excellent results when tested on the two- dimensional Ising model, and the method, as generalized, provides a framework for an analytical approach to complex systems. Monte Carlo simulations of the fully frustrated XY model in a magnetic field provide further evidence of two transitions. The magnetic field breaks the rotational symmetry of the model, but the two-fold chiral degeneracy of the ground state persists in the field. This lower degeneracy with the field present makes Monte Carlo simulations converge more rapidly. The critical exponent δ determined from the sublattice magnetizations as a function of field agrees with the value expected for a Kosterlitz-Thouless transition. Further, the zero-field specific heat obtained by extrapolation from simulations in a

  16. Self-consistent imbedding and the ellipsoidal model model for porous rocks

    International Nuclear Information System (INIS)

    Korringa, J.; Brown, R.J.S.; Thompson, D.D.; Runge, R.J.

    1979-01-01

    Equations are obtained for the effective elastic moduli for a model of an isotropic, heterogeneous, porous medium. The mathematical model used for computation is abstract in that it is not simply a rigorous computation for a composite medium of some idealized geometry, although the computation contains individual steps which are just that. Both the solid part and pore space are represented by ellipsoidal or spherical 'grains' or 'pores' of various sizes and shapes. The strain of each grain, caused by external forces applied to the medium, is calculated in a self-consistent imbedding (SCI) approximation, which replaces the true surrounding of any given grain or pore by an isotropic medium defined by the effective moduli to be computed. The ellipsoidal nature of the shapes allows us to use Eshelby's theoretical treatment of a single ellipsoidal inclusion in an infiinte homogeneous medium. Results are compared with the literature, and discrepancies are found with all published accounts of this problem. Deviations from the work of Wu, of Walsh, and of O'Connell and Budiansky are attributed to a substitution made by these authors which though an identity for the exact quantities involved, is only approximate in the SCI calculation. This reduces the validity of the equations to first-order effects only. Differences with the results of Kuster and Toksoez are attributed to the fact that the computation of these authors is not self-consistent in the sense used here. A result seems to be the stiffening of the medium as if the pores are held apart. For spherical grains and pores, their calculated moduli are those given by the Hashin-Shtrikman upper bounds. Our calculation reproduces, in the case of spheres, an early result of Budiansky. An additional feature of our work is that the algebra is simpler than in earlier work. We also incorporate into the theory the possibility that fluid-filled pores are interconnected

  17. Smoothed Particle Hydrodynamics: A consistent model for interfacial multiphase fluid flow simulations

    Science.gov (United States)

    Krimi, Abdelkader; Rezoug, Mehdi; Khelladi, Sofiane; Nogueira, Xesús; Deligant, Michael; Ramírez, Luis

    2018-04-01

    In this work, a consistent Smoothed Particle Hydrodynamics (SPH) model to deal with interfacial multiphase fluid flows simulation is proposed. A modification to the Continuum Stress Surface formulation (CSS) [1] to enhance the stability near the fluid interface is developed in the framework of the SPH method. A non-conservative first-order consistency operator is used to compute the divergence of stress surface tensor. This formulation benefits of all the advantages of the one proposed by Adami et al. [2] and, in addition, it can be applied to more than two phases fluid flow simulations. Moreover, the generalized wall boundary conditions [3] are modified in order to be well adapted to multiphase fluid flows with different density and viscosity. In order to allow the application of this technique to wall-bounded multiphase flows, a modification of generalized wall boundary conditions is presented here for using the SPH method. In this work we also present a particle redistribution strategy as an extension of the damping technique presented in [3] to smooth the initial transient phase of gravitational multiphase fluid flow simulations. Several computational tests are investigated to show the accuracy, convergence and applicability of the proposed SPH interfacial multiphase model.

  18. Self-Consistent Generation of Primordial Continental Crust in Global Mantle Convection Models

    Science.gov (United States)

    Jain, C.; Rozel, A.; Tackley, P. J.

    2017-12-01

    We present the generation of primordial continental crust (TTG rocks) using self-consistent and evolutionary thermochemical mantle convection models (Tackley, PEPI 2008). Numerical modelling commonly shows that mantle convection and continents have strong feedbacks on each other. However in most studies, continents are inserted a priori while basaltic (oceanic) crust is generated self-consistently in some models (Lourenco et al., EPSL 2016). Formation of primordial continental crust happened by fractional melting and crystallisation in episodes of relatively rapid growth from late Archean to late Proterozoic eras (3-1 Ga) (Hawkesworth & Kemp, Nature 2006) and it has also been linked to the onset of plate tectonics around 3 Ga. It takes several stages of differentiation to generate Tonalite-Trondhjemite-Granodiorite (TTG) rocks or proto-continents. First, the basaltic magma is extracted from the pyrolitic mantle which is both erupted at the surface and intruded at the base of the crust. Second, it goes through eclogitic transformation and then partially melts to form TTGs (Rudnick, Nature 1995; Herzberg & Rudnick, Lithos 2012). TTGs account for the majority of the Archean continental crust. Based on the melting conditions proposed by Moyen (Lithos 2011), the feasibility of generating TTG rocks in numerical simulations has already been demonstrated by Rozel et al. (Nature, 2017). Here, we have developed the code further by parameterising TTG formation. We vary the ratio of intrusive (plutonic) and extrusive (volcanic) magmatism (Crisp, Volcanol. Geotherm. 1984) to study the relative volumes of three petrological TTG compositions as reported from field data (Moyen, Lithos 2011). Furthermore, we systematically vary parameters such as friction coefficient, initial core temperature and composition-dependent viscosity to investigate the global tectonic regime of early Earth. Continental crust can also be destroyed by subduction or delamination. We will investigate

  19. Consistency and discrepancy in the atmospheric response to Arctic sea-ice loss across climate models

    Science.gov (United States)

    Screen, James A.; Deser, Clara; Smith, Doug M.; Zhang, Xiangdong; Blackport, Russell; Kushner, Paul J.; Oudar, Thomas; McCusker, Kelly E.; Sun, Lantao

    2018-02-01

    The decline of Arctic sea ice is an integral part of anthropogenic climate change. Sea-ice loss is already having a significant impact on Arctic communities and ecosystems. Its role as a cause of climate changes outside of the Arctic has also attracted much scientific interest. Evidence is mounting that Arctic sea-ice loss can affect weather and climate throughout the Northern Hemisphere. The remote impacts of Arctic sea-ice loss can only be properly represented using models that simulate interactions among the ocean, sea ice, land and atmosphere. A synthesis of six such experiments with different models shows consistent hemispheric-wide atmospheric warming, strongest in the mid-to-high-latitude lower troposphere; an intensification of the wintertime Aleutian Low and, in most cases, the Siberian High; a weakening of the Icelandic Low; and a reduction in strength and southward shift of the mid-latitude westerly winds in winter. The atmospheric circulation response seems to be sensitive to the magnitude and geographic pattern of sea-ice loss and, in some cases, to the background climate state. However, it is unclear whether current-generation climate models respond too weakly to sea-ice change. We advocate for coordinated experiments that use different models and observational constraints to quantify the climate response to Arctic sea-ice loss.

  20. Development of a Kohn-Sham like potential in the Self-Consistent Atomic Deformation Model

    OpenAIRE

    Mehl, M. J.; Boyer, L. L.; Stokes, H. T.

    1996-01-01

    This is a brief description of how to derive the local ``atomic'' potentials from the Self-Consistent Atomic Deformation (SCAD) model density function. Particular attention is paid to the spherically averaged case.

  1. Consistency, Verification, and Validation of Turbulence Models for Reynolds-Averaged Navier-Stokes Applications

    Science.gov (United States)

    Rumsey, Christopher L.

    2009-01-01

    In current practice, it is often difficult to draw firm conclusions about turbulence model accuracy when performing multi-code CFD studies ostensibly using the same model because of inconsistencies in model formulation or implementation in different codes. This paper describes an effort to improve the consistency, verification, and validation of turbulence models within the aerospace community through a website database of verification and validation cases. Some of the variants of two widely-used turbulence models are described, and two independent computer codes (one structured and one unstructured) are used in conjunction with two specific versions of these models to demonstrate consistency with grid refinement for several representative problems. Naming conventions, implementation consistency, and thorough grid resolution studies are key factors necessary for success.

  2. A paradigm shift toward a consistent modeling framework to assess climate impacts

    Science.gov (United States)

    Monier, E.; Paltsev, S.; Sokolov, A. P.; Fant, C.; Chen, H.; Gao, X.; Schlosser, C. A.; Scott, J. R.; Dutkiewicz, S.; Ejaz, Q.; Couzo, E. A.; Prinn, R. G.; Haigh, M.

    2017-12-01

    Estimates of physical and economic impacts of future climate change are subject to substantial challenges. To enrich the currently popular approaches of assessing climate impacts by evaluating a damage function or by multi-model comparisons based on the Representative Concentration Pathways (RCPs), we focus here on integrating impacts into a self-consistent coupled human and Earth system modeling framework that includes modules that represent multiple physical impacts. In a sample application we show that this framework is capable of investigating the physical impacts of climate change and socio-economic stressors. The projected climate impacts vary dramatically across the globe in a set of scenarios with global mean warming ranging between 2.4°C and 3.6°C above pre-industrial by 2100. Unabated emissions lead to substantial sea level rise, acidification that impacts the base of the oceanic food chain, air pollution that exceeds health standards by tenfold, water stress that impacts an additional 1 to 2 billion people globally and agricultural productivity that decreases substantially in many parts of the world. We compare the outcomes from these forward-looking scenarios against the common goal described by the target-driven scenario of 2°C, which results in much smaller impacts. It is challenging for large internationally coordinated exercises to respond quickly to new policy targets. We propose that a paradigm shift toward a self-consistent modeling framework to assess climate impacts is needed to produce information relevant to evolving global climate policy and mitigation strategies in a timely way.

  3. Self-Consistent Atmosphere Models of the Most Extreme Hot Jupiters

    Science.gov (United States)

    Lothringer, Joshua; Barman, Travis

    2018-01-01

    We present a detailed look at self-consistent PHOENIX atmosphere models of the most highly irradiated hot Jupiters known to exist. These hot Jupiters typically have equilibrium temperatures approaching and sometimes exceeding 3000 K, orbiting A, F, and early-G type stars on orbits less than 0.03 AU (10x closer than Mercury is to the Sun). The most extreme example, KELT-9b, is the hottest known hot Jupiter with a measured dayside temperature of 4600 K. Many of the planets we model have recently attracted attention with high profile discoveries, including temperature inversions in WASP-33b and WASP-121, changing phase curve offsets possibly caused by magnetohydrodymanic effects in HAT-P-7b, and TiO in WASP-19b. Our modeling provides a look at the a priori expectations for these planets and helps us understand these recent discoveries. We show that, in the hottest cases, all molecules are dissociated down to relatively high pressures. These planets may have detectable temperature inversions, more akin to thermospheres than stratospheres in that an optical absorber like TiO or VO is not needed. Instead, the inversions are created by a lack of cooling in the IR combined with heating from atoms and ions at UV and blue optical wavelengths. We also reevaluate some of the assumptions that have been made in retrieval analyses of these planets.

  4. Consistent constitutive modeling of metallic target penetration using empirical, analytical, and numerical penetration models

    Directory of Open Access Journals (Sweden)

    John (Jack P. Riegel III

    2016-04-01

    Full Text Available Historically, there has been little correlation between the material properties used in (1 empirical formulae, (2 analytical formulations, and (3 numerical models. The various regressions and models may each provide excellent agreement for the depth of penetration into semi-infinite targets. But the input parameters for the empirically based procedures may have little in common with either the analytical model or the numerical model. This paper builds on previous work by Riegel and Anderson (2014 to show how the Effective Flow Stress (EFS strength model, based on empirical data, can be used as the average flow stress in the analytical Walker–Anderson Penetration model (WAPEN (Anderson and Walker, 1991 and how the same value may be utilized as an effective von Mises yield strength in numerical hydrocode simulations to predict the depth of penetration for eroding projectiles at impact velocities in the mechanical response regime of the materials. The method has the benefit of allowing the three techniques (empirical, analytical, and numerical to work in tandem. The empirical method can be used for many shot line calculations, but more advanced analytical or numerical models can be employed when necessary to address specific geometries such as edge effects or layering that are not treated by the simpler methods. Developing complete constitutive relationships for a material can be costly. If the only concern is depth of penetration, such a level of detail may not be required. The effective flow stress can be determined from a small set of depth of penetration experiments in many cases, especially for long penetrators such as the L/D = 10 ones considered here, making it a very practical approach. In the process of performing this effort, the authors considered numerical simulations by other researchers based on the same set of experimental data that the authors used for their empirical and analytical assessment. The goals were to establish a

  5. Requirements for UML and OWL Integration Tool for User Data Consistency Modeling and Testing

    DEFF Research Database (Denmark)

    Nytun, J. P.; Jensen, Christian Søndergaard; Oleshchuk, V. A.

    2003-01-01

    The amount of data available on the Internet is continuously increasing, consequentially there is a growing need for tools that help to analyse the data. Testing of consistency among data received from different sources is made difficult by the number of different languages and schemas being used....... In this paper we analyze requirements for a tool that support integration of UML models and ontologies written in languages like the W3C Web Ontology Language (OWL). The tool can be used in the following way: after loading two legacy models into the tool, the tool user connects them by inserting modeling......, an important part of this technique is attaching of OCL expressions to special boolean class attributes that we call consistency attributes. The resulting integration model can be used for automatic consistency testing of two instances of the legacy models by automatically instantiate the whole integration...

  6. Alterations in Striatal Synaptic Transmission are Consistent across Genetic Mouse Models of Huntington's Disease

    Directory of Open Access Journals (Sweden)

    Damian M Cummings

    2010-05-01

    Full Text Available Since the identification of the gene responsible for HD (Huntington's disease, many genetic mouse models have been generated. Each employs a unique approach for delivery of the mutated gene and has a different CAG repeat length and background strain. The resultant diversity in the genetic context and phenotypes of these models has led to extensive debate regarding the relevance of each model to the human disorder. Here, we compare and contrast the striatal synaptic phenotypes of two models of HD, namely the YAC128 mouse, which carries the full-length huntingtin gene on a yeast artificial chromosome, and the CAG140 KI*** (knock-in mouse, which carries a human/mouse chimaeric gene that is expressed in the context of the mouse genome, with our previously published data obtained from the R6/2 mouse, which is transgenic for exon 1 mutant huntingtin. We show that striatal MSNs (medium-sized spiny neurons in YAC128 and CAG140 KI mice have similar electrophysiological phenotypes to that of the R6/2 mouse. These include a progressive increase in membrane input resistance, a reduction in membrane capacitance, a lower frequency of spontaneous excitatory postsynaptic currents and a greater frequency of spontaneous inhibitory postsynaptic currents in a subpopulation of striatal neurons. Thus, despite differences in the context of the inserted gene between these three models of HD, the primary electrophysiological changes observed in striatal MSNs are consistent. The outcomes suggest that the changes are due to the expression of mutant huntingtin and such alterations can be extended to the human condition.

  7. Validation study of the magnetically self-consistent inner magnetosphere model RAM-SCB

    Science.gov (United States)

    Yu, Yiqun; Jordanova, Vania; Zaharia, Sorin; Koller, Josef; Zhang, Jichun; Kistler, Lynn M.

    2012-03-01

    The validation of the magnetically self-consistent inner magnetospheric model RAM-SCB developed at Los Alamos National Laboratory is presented here. The model consists of two codes: a kinetic ring current-atmosphere interaction model (RAM) and a 3-D equilibrium magnetic field code (SCB). The validation is conducted by simulating two magnetic storm events and then comparing the model results against a variety of satellite in situ observations, including the magnetic field from Cluster and Polar spacecraft, ion differential flux from the Cluster/CODIF (Composition and Distribution Function) analyzer, and the ground-based SYM-H index. The model prediction of the magnetic field is in good agreement with observations, which indicates the model's capability of representing well the inner magnetospheric field configuration. This provides confidence for the RAM-SCB model to be utilized for field line and drift shell tracing, which are needed in radiation belt studies. While the SYM-H index, which reflects the total ring current energy content, is generally reasonably reproduced by the model using the Weimer electric field model, the modeled ion differential flux clearly depends on the electric field strength, local time, and magnetic activity level. A self-consistent electric field approach may be needed to improve the model performance in this regard.

  8. Self-consistent treatment of quark-quark interaction in MIT bag model

    CERN Document Server

    Simonis, V

    1997-01-01

    Some features of the MlT bag model are discussed with particular emphasis on static, spherical cavity approximation to the model. A self-consistent procedure for obtaining wave functions and calculating gluon exchange effects is proposed. The equations derived are similar to state-dependent relativistic Hartree-Fock equations. (author)

  9. Estimating long-term volatility parameters for market-consistent models

    African Journals Online (AJOL)

    Contemporary actuarial and accounting practices (APN 110 in the South African context) require the use of market-consistent models for the valuation of embedded investment derivatives. These models have to be calibrated with accurate and up-to-date market data. Arguably, the most important variable in the valuation of ...

  10. A parameter study of self-consistent disk models around Herbig AeBe stars

    NARCIS (Netherlands)

    Meijer, J.; Dominik, C.; de Koter, A.; Dullemond, C.P.; van Boekel, R.; Waters, L.B.F.M.

    2008-01-01

    We present a parameter study of self-consistent models of protoplanetary disks around Herbig AeBe stars. We use the code developed by Dullemond and Dominik, which solves the 2D radiative transfer problem including an iteration for the vertical hydrostatic structure of the disk. This grid of models

  11. Linking lipid architecture to bilayer structure and mechanics using self-consistent field modelling

    NARCIS (Netherlands)

    Pera, H.; Kleijn, J.M.; Leermakers, F.A.M.

    2014-01-01

    To understand how lipid architecture determines the lipid bilayer structure and its mechanics, we implement a molecularly detailed model that uses the self-consistent field theory. This numerical model accurately predicts parameters such as Helfrichs mean and Gaussian bending modulus k c and k ¯ and

  12. Self-consistent field modeling of adsorption from polymer/surfactant mixtures

    NARCIS (Netherlands)

    Postmus, B.R.; Leermakers, F.A.M.; Cohen Stuart, M.A.

    2008-01-01

    We report on the development of a self-consistent field model that describes the competitive adsorption of nonionic alkyl-(ethylene oxide) surfactants and nonionic polymer poly(ethylene oxide) (PEO) from aqueous solutions onto silica. The model explicitly describes the response to the pH and the

  13. New geometric design consistency model based on operating speed profiles for road safety evaluation.

    Science.gov (United States)

    Camacho-Torregrosa, Francisco J; Pérez-Zuriaga, Ana M; Campoy-Ungría, J Manuel; García-García, Alfredo

    2013-12-01

    To assist in the on-going effort to reduce road fatalities as much as possible, this paper presents a new methodology to evaluate road safety in both the design and redesign stages of two-lane rural highways. This methodology is based on the analysis of road geometric design consistency, a value which will be a surrogate measure of the safety level of the two-lane rural road segment. The consistency model presented in this paper is based on the consideration of continuous operating speed profiles. The models used for their construction were obtained by using an innovative GPS-data collection method that is based on continuous operating speed profiles recorded from individual drivers. This new methodology allowed the researchers to observe the actual behavior of drivers and to develop more accurate operating speed models than was previously possible with spot-speed data collection, thereby enabling a more accurate approximation to the real phenomenon and thus a better consistency measurement. Operating speed profiles were built for 33 Spanish two-lane rural road segments, and several consistency measurements based on the global and local operating speed were checked. The final consistency model takes into account not only the global dispersion of the operating speed, but also some indexes that consider both local speed decelerations and speeds over posted speeds as well. For the development of the consistency model, the crash frequency for each study site was considered, which allowed estimating the number of crashes on a road segment by means of the calculation of its geometric design consistency. Consequently, the presented consistency evaluation method is a promising innovative tool that can be used as a surrogate measure to estimate the safety of a road segment. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Self-Consistent Model of Magnetospheric Electric Field, Ring Current, Plasmasphere, and Electromagnetic Ion Cyclotron Waves: Initial Results

    Science.gov (United States)

    Gamayunov, K. V.; Khazanov, G. V.; Liemohn, M. W.; Fok, M.-C.; Ridley, A. J.

    2009-01-01

    Further development of our self-consistent model of interacting ring current (RC) ions and electromagnetic ion cyclotron (EMIC) waves is presented. This model incorporates large scale magnetosphere-ionosphere coupling and treats self-consistently not only EMIC waves and RC ions, but also the magnetospheric electric field, RC, and plasmasphere. Initial simulations indicate that the region beyond geostationary orbit should be included in the simulation of the magnetosphere-ionosphere coupling. Additionally, a self-consistent description, based on first principles, of the ionospheric conductance is required. These initial simulations further show that in order to model the EMIC wave distribution and wave spectral properties accurately, the plasmasphere should also be simulated self-consistently, since its fine structure requires as much care as that of the RC. Finally, an effect of the finite time needed to reestablish a new potential pattern throughout the ionosphere and to communicate between the ionosphere and the equatorial magnetosphere cannot be ignored.

  15. Height-Diameter Models for Mixed-Species Forests Consisting of Spruce, Fir, and Beech

    Directory of Open Access Journals (Sweden)

    Petráš Rudolf

    2014-06-01

    Full Text Available Height-diameter models define the general relationship between the tree height and diameter at each growth stage of the forest stand. This paper presents generalized height-diameter models for mixed-species forest stands consisting of Norway spruce (Picea abies Karst., Silver fir (Abies alba L., and European beech (Fagus sylvatica L. from Slovakia. The models were derived using two growth functions from the exponential family: the two-parameter Michailoff and three-parameter Korf functions. Generalized height-diameter functions must normally be constrained to pass through the mean stand diameter and height, and then the final growth model has only one or two parameters to be estimated. These “free” parameters are then expressed over the quadratic mean diameter, height and stand age and the final mathematical form of the model is obtained. The study material included 50 long-term experimental plots located in the Western Carpathians. The plots were established 40-50 years ago and have been repeatedly measured at 5 to 10-year intervals. The dataset includes 7,950 height measurements of spruce, 21,661 of fir and 5,794 of beech. As many as 9 regression models were derived for each species. Although the “goodness of fit” of all models showed that they were generally well suited for the data, the best results were obtained for silver fir. The coefficient of determination ranged from 0.946 to 0.948, RMSE (m was in the interval 1.94-1.97 and the bias (m was -0.031 to 0.063. Although slightly imprecise parameter estimation was established for spruce, the estimations of the regression parameters obtained for beech were quite less precise. The coefficient of determination for beech was 0.854-0.860, RMSE (m 2.67-2.72, and the bias (m ranged from -0.144 to -0.056. The majority of models using Korf’s formula produced slightly better estimations than Michailoff’s, and it proved immaterial which estimated parameter was fixed and which parameters

  16. An Ice Model That is Consistent with Composite Rheology in GIA Modelling

    Science.gov (United States)

    Huang, P.; Patrick, W.

    2017-12-01

    There are several popular approaches in constructing ice history models. One of them is mainly based on thermo-mechanical ice models with forcing or boundary conditions inferred from paleoclimate data. The second one is mainly based on the observed response of the Earth to glacial loading and unloading, a process called Glacial Isostatic Adjustment or GIA. The third approach is a hybrid version of the first and second approaches. In this presentation, we will follow the second approach which also uses geological data such as ice flow, terminal moraine data and simple ice dynamic for the ice sheet re-construction (Peltier & Andrew 1976). The global ice model ICE-6G (Peltier et al. 2015) and all its predecessors (Tushingham & Peltier 1991, Peltier 1994, 1996, 2004, Lambeck et al. 2014) are constructed this way with the assumption that mantle rheology is linear. However, high temperature creep experiments on mantle rocks show that non-linear creep laws can also operate in the mantle. Since both linear (e.g. diffusion creep) and non-linear (e.g. dislocation) creep laws can operate simultaneously in the mantle, mantle rheology is likely composite, where the total creep is the sum of both linear and onlinear creep. Preliminary GIA studies found that composite rheology can fit regional RSL observations better than that from linear rheology(e.g. van der Wal et al. 2010). The aim of this paper is to construct ice models in Laurentia and Fennoscandia using this second approach, but with composite rheology, so that its predictions can fit GIA observations such as global RSL data, land uplift rate and g-dot simultaneously in addition to geological data and simple ice dynamics. The g-dot or gravity-rate-of-change data is from the GRACE gravity mission but with the effects of hydrology removed. Our GIA model is based on the Coupled Laplace-Finite Element method as described in Wu(2004) and van der Wal et al.(2010). It is found that composite rheology generally supports a thicker

  17. Cortical Astrocytes Acutely Exposed to the Monomethylarsonous Acid (MMAIII) Show Increased Pro-inflammatory Cytokines Gene Expression that is Consistent with APP and BACE-1: Over-expression.

    Science.gov (United States)

    Escudero-Lourdes, C; Uresti-Rivera, E E; Oliva-González, C; Torres-Ramos, M A; Aguirre-Bañuelos, P; Gandolfi, A J

    2016-10-01

    Long-term exposure to inorganic arsenic (iAs) through drinking water has been associated with cognitive impairment in children and adults; however, the related pathogenic mechanisms have not been completely described. Increased or chronic inflammation in the brain is linked to impaired cognition and neurodegeneration; iAs induces strong inflammatory responses in several cells, but this effect has been poorly evaluated in central nervous system (CNS) cells. Because astrocytes are the most abundant cells in the CNS and play a critical role in brain homeostasis, including regulation of the inflammatory response, any functional impairment in them can be deleterious for the brain. We propose that iAs could induce cognitive impairment through inflammatory response activation in astrocytes. In the present work, rat cortical astrocytes were acutely exposed in vitro to the monomethylated metabolite of iAs (MMA III ), which accumulates in glial cells without compromising cell viability. MMA III LD 50 in astrocytes was 10.52 μM, however, exposure to sub-toxic MMA III concentrations (50-1000 nM) significantly increased IL-1β, IL-6, TNF-α, COX-2, and MIF-1 gene expression. These effects were consistent with amyloid precursor protein (APP) and β-secretase (BACE-1) increased gene expression, mainly for those MMA III concentrations that also induced TNF-α over-expression. Other effects of MMA III on cortical astrocytes included increased proliferative and metabolic activity. All tested MMA III concentrations led to an inhibition of intracellular lactate dehydrogenase (LDH) activity. Results suggest that MMA III induces important metabolic and functional changes in astrocytes that may affect brain homeostasis and that inflammation may play a major role in cognitive impairment-related pathogenicity in As-exposed populations.

  18. Study of impurity effects on CFETR steady-state scenario by self-consistent integrated modeling

    Science.gov (United States)

    Shi, Nan; Chan, Vincent S.; Jian, Xiang; Li, Guoqiang; Chen, Jiale; Gao, Xiang; Shi, Shengyu; Kong, Defeng; Liu, Xiaoju; Mao, Shifeng; Xu, Guoliang

    2017-12-01

    Impurity effects on fusion performance of China fusion engineering test reactor (CFETR) due to extrinsic seeding are investigated. An integrated 1.5D modeling workflow evolves plasma equilibrium and all transport channels to steady state. The one modeling framework for integrated tasks framework is used to couple the transport solver, MHD equilibrium solver, and source and sink calculations. A self-consistent impurity profile constructed using a steady-state background plasma, which satisfies quasi-neutrality and true steady state, is presented for the first time. Studies are performed based on an optimized fully non-inductive scenario with varying concentrations of Argon (Ar) seeding. It is found that fusion performance improves before dropping off with increasing {{Z}\\text{eff}} , while the confinement remains at high level. Further analysis of transport for these plasmas shows that low-k ion temperature gradient modes dominate the turbulence. The decrease in linear growth rate and resultant fluxes of all channels with increasing {{Z}\\text{eff}} can be traced to impurity profile change by transport. The improvement in confinement levels off at higher {{Z}\\text{eff}} . Over the regime of study there is a competition between the suppressed transport and increasing radiation that leads to a peak in the fusion performance at {{Z}\\text{eff}} (~2.78 for CFETR). Extrinsic impurity seeding to control divertor heat load will need to be optimized around this value for best fusion performance.

  19. An island of stability: art images and natural scenes—but not natural faces—show consistent aesthetic response in Alzheimer’s-related dementia.

    Directory of Open Access Journals (Sweden)

    Daniel eGraham

    2013-03-01

    Full Text Available Alzheimer’s disease causes severe impairments in cognitive function but there is evidence that aspects of aesthetic perception are somewhat spared, at least in early stages of the disease. People with early Alzheimer’s-related dementia have been found to show similar degrees of stability over time in aesthetic judgment of paintings compared to controls, despite poor explicit memory for the images. Here we expand on this line of inquiry to investigate the types of perceptual judgments involved, and to test whether people in later stages of the disease also show evidence of preserved aesthetic judgment. Our results confirm that, compared to healthy controls, there is similar aesthetic stability in early stage Alzheimer’s disease (AD in the absence of explicit memory, and we report here that people with later stages of the disease also show similar stability compared to controls. However, while we find that stability for portrait paintings, landscape paintings, and landscape photographs is not different compared to control group performance, stability for face photographs—which were matched for identity with the portrait paintings—was significantly impaired in the AD group. We suggest that partially spared face-processing systems interfere with aesthetic processing of natural faces in ways that are not found for artistic images and landscape photographs. Thus, our work provides a novel form of evidence regarding face processing in healthy and diseased ageing. Our work also gives insights into general theories of aesthetics, since people with Alzheimer’s disease are not encumbered by many of the semantic and emotional factors that otherwise color aesthetic judgment. We conclude that, for people with Alzheimer’s disease, basic aesthetic judgment of artistic images represents an island of stability in a condition that in most other respects causes profound cognitive disruption. As such, aesthetic response could be a promising route to

  20. An Island of Stability: Art Images and Natural Scenes - but Not Natural Faces - Show Consistent Esthetic Response in Alzheimer's-Related Dementia.

    Science.gov (United States)

    Graham, Daniel J; Stockinger, Simone; Leder, Helmut

    2013-01-01

    Alzheimer's disease (AD) causes severe impairments in cognitive function but there is evidence that aspects of esthetic perception are somewhat spared, at least in early stages of the disease. People with early Alzheimer's-related dementia have been found to show similar degrees of stability over time in esthetic judgment of paintings compared to controls, despite poor explicit memory for the images. Here we expand on this line of inquiry to investigate the types of perceptual judgments involved, and to test whether people in later stages of the disease also show evidence of preserved esthetic judgment. Our results confirm that, compared to healthy controls, there is similar esthetic stability in early stage AD in the absence of explicit memory, and we report here that people with later stages of the disease also show similar stability compared to controls. However, while we find that stability for portrait paintings, landscape paintings, and landscape photographs is not different compared to control group performance, stability for face photographs - which were matched for identity with the portrait paintings - was significantly impaired in the AD group. We suggest that partially spared face-processing systems interfere with esthetic processing of natural faces in ways that are not found for artistic images and landscape photographs. Thus, our work provides a novel form of evidence regarding face-processing in healthy and diseased aging. Our work also gives insights into general theories of esthetics, since people with AD are not encumbered by many of the semantic and emotional factors that otherwise color esthetic judgment. We conclude that, for people with AD, basic esthetic judgment of artistic images represents an "island of stability" in a condition that in most other respects causes profound cognitive disruption. As such, esthetic response could be a promising route to future therapies.

  1. A WFS1 Haplotype Consisting of the Minor Alleles of rs752854, rs10010131, and rs734312 Shows a Protective Role Against Type 2 Diabetes in Russian Patients

    OpenAIRE

    Chistiakov, Dimitry A; Khodyrev, Dmitry S.; Smetanina, Svetlana A.; Bel'chikova, Larisa N.; Suplotova, Lyudmila A.; Nosikov, Valery V.

    2010-01-01

    BACKGROUND: Rare variants of the WFS1 gene encoding wolframin cause Wolfram syndrome, a monogenic disease associated with diabetes insipidus, diabetes mellitus, optic atrophy, and deafness. In contrast, common variants of WFS1 showed association with type 2 diabetes (T2D) in numerous Caucasian populations. AIM: In this study, we tested whether the markers rs752854, rs10010131, and rs734312, located in the WFS1 gene, are related to the development of T2D in a Russian population. METHODS: The p...

  2. Self-consistent evolution models for slow CMEs up to 1 AU

    Science.gov (United States)

    Poedts, S.; Pomoell, J.; Zuccarello, F. P.

    2016-02-01

    Our 2.5D (axi-symmetric) self-consistent numerical magneto-hydrodynamics (MHD) models for the onset of CMEs under solar minimum conditions and for their interaction with coronal streamers and subsequent evolution up to 1 AU, are presented and discussed. The CMEs are initiated by magnetic flux emergence/cancellation and/or by shearing the magnetic foot points of a magnetic arcade which is positioned above or below the equatorial plane and embedded in a larger helmet streamer. The overlying magnetic streamer field then deflects the CMEs towards the equator, and the deflection path is dependent on the driving velocity. The core of the CME, created during the onset process, contains a magnetic flux rope and the synthetic white light images often show the typical three-part CME structure. The resulting CMEs propagate only slightly faster than the background solar wind, but this small excess speed is high enough to create a fast MHD shock wave from a distance of 0.25 AU onwards. At 1 AU, the plasma shows the typical characteristics of a magnetic cloud, and the simulated data are in good agreement with the (ACE) observations.

  3. Self-consistent collisional-radiative model for hydrogen atoms: Atom–atom interaction and radiation transport

    International Nuclear Information System (INIS)

    Colonna, G.; Pietanza, L.D.; D’Ammando, G.

    2012-01-01

    Graphical abstract: Self-consistent coupling between radiation, state-to-state kinetics, electron kinetics and fluid dynamics. Highlight: ► A CR model of shock-wave in hydrogen plasma has been presented. ► All equations have been coupled self-consistently. ► Non-equilibrium electron and level distributions are obtained. ► The results show non-local effects and non-equilibrium radiation. - Abstract: A collisional-radiative model for hydrogen atom, coupled self-consistently with the Boltzmann equation for free electrons, has been applied to model a shock tube. The kinetic model has been completed considering atom–atom collisions and the vibrational kinetics of the ground state of hydrogen molecules. The atomic level kinetics has been also coupled with a radiative transport equation to determine the effective adsorption and emission coefficients and non-local energy transfer.

  4. Collaborative CAD Synchronization Based on a Symmetric and Consistent Modeling Procedure

    Directory of Open Access Journals (Sweden)

    Yiqi Wu

    2017-04-01

    Full Text Available One basic issue with collaborative computer aided design (Co-CAD is how to maintain valid and consistent modeling results across all design sites. Moreover, modeling history is important in parametric CAD modeling. Therefore, different from a typical co-editing approach, this paper proposes a novel method for Co-CAD synchronization, in which all Co-CAD sites maintain symmetric and consistent operating procedures. Consequently, the consistency of both modeling results and history can be achieved. In order to generate a valid, unique, and symmetric queue among collaborative sites, a set of correlated mechanisms is presented in this paper. Firstly, the causal relationship of operations is maintained. Secondly, the operation queue is reconstructed for partial concurrency operation, and the concurrent operation can be retrieved. Thirdly, a symmetric, concurrent operation control strategy is proposed to determine the order of operations and resolve possible conflicts. Compared with existing Co-CAD consistency methods, the proposed method is convenient and flexible in supporting collaborative design. The experiment performed based on the collaborative modeling procedure demonstrates the correctness and applicability of this work.

  5. Towards an Information Model of Consistency Maintenance in Distributed Interactive Applications

    Directory of Open Access Journals (Sweden)

    Xin Zhang

    2008-01-01

    Full Text Available A novel framework to model and explore predictive contract mechanisms in distributed interactive applications (DIAs using information theory is proposed. In our model, the entity state update scheme is modelled as an information generation, encoding, and reconstruction process. Such a perspective facilitates a quantitative measurement of state fidelity loss as a result of the distribution protocol. Results from an experimental study on a first-person shooter game are used to illustrate the utility of this measurement process. We contend that our proposed model is a starting point to reframe and analyse consistency maintenance in DIAs as a problem in distributed interactive media compression.

  6. A pedestal temperature model with self-consistent calculation of safety factor and magnetic shear

    International Nuclear Information System (INIS)

    Onjun, T; Siriburanon, T; Onjun, O

    2008-01-01

    A pedestal model based on theory-motivated models for the pedestal width and the pedestal pressure gradient is developed for the temperature at the top of the H-mode pedestal. The pedestal width model based on magnetic shear and flow shear stabilization is used in this study, where the pedestal pressure gradient is assumed to be limited by first stability of infinite n ballooning mode instability. This pedestal model is implemented in the 1.5D BALDUR integrated predictive modeling code, where the safety factor and magnetic shear are solved self-consistently in both core and pedestal regions. With the self-consistently approach for calculating safety factor and magnetic shear, the effect of bootstrap current can be correctly included in the pedestal model. The pedestal model is used to provide the boundary conditions in the simulations and the Multi-mode core transport model is used to describe the core transport. This new integrated modeling procedure of the BALDUR code is used to predict the temperature and density profiles of 26 H-mode discharges. Simulations are carried out for 13 discharges in the Joint European Torus and 13 discharges in the DIII-D tokamak. The average root-mean-square deviation between experimental data and the predicted profiles of the temperature and the density, normalized by their central values, is found to be about 14%

  7. A self-consistent kinetic modeling of a 1-D, bounded, plasma in ...

    Indian Academy of Sciences (India)

    Abstract. A self-consistent kinetic treatment is presented here, where the Boltzmann equation is solved for a particle ... This paper reports on the findings of a kinetic code that retains col- lisions and sources, models ..... was used in the runs reported in this paper, the source of particles is modified from the explicit source Л(Ъ).

  8. A new self-consistent model for thermodynamics of binary solutions

    Czech Academy of Sciences Publication Activity Database

    Svoboda, Jiří; Shan, Y. V.; Fischer, F. D.

    2015-01-01

    Roč. 108, NOV (2015), s. 27-30 ISSN 1359-6462 R&D Projects: GA ČR(CZ) GA14-24252S Institutional support: RVO:68081723 Keywords : Thermodynamics * Analytical methods * CALPHAD * Phase diagram * Self-consistent model Subject RIV: BJ - Thermodynamics Impact factor: 3.305, year: 2015

  9. Topologically Consistent Models for Efficient Big Geo-Spatio Data Distribution

    Science.gov (United States)

    Jahn, M. W.; Bradley, P. E.; Doori, M. Al; Breunig, M.

    2017-10-01

    Geo-spatio-temporal topology models are likely to become a key concept to check the consistency of 3D (spatial space) and 4D (spatial + temporal space) models for emerging GIS applications such as subsurface reservoir modelling or the simulation of energy and water supply of mega or smart cities. Furthermore, the data management for complex models consisting of big geo-spatial data is a challenge for GIS and geo-database research. General challenges, concepts, and techniques of big geo-spatial data management are presented. In this paper we introduce a sound mathematical approach for a topologically consistent geo-spatio-temporal model based on the concept of the incidence graph. We redesign DB4GeO, our service-based geo-spatio-temporal database architecture, on the way to the parallel management of massive geo-spatial data. Approaches for a new geo-spatio-temporal and object model of DB4GeO meeting the requirements of big geo-spatial data are discussed in detail. Finally, a conclusion and outlook on our future research are given on the way to support the processing of geo-analytics and -simulations in a parallel and distributed system environment.

  10. Numerical simulation of a thermodynamically consistent four-species tumor growth model.

    Science.gov (United States)

    Hawkins-Daarud, Andrea; van der Zee, Kristoffer G; Oden, J Tinsley

    2012-01-01

    In this paper, we develop a thermodynamically consistent four-species model of tumor growth on the basis of the continuum theory of mixtures. Unique to this model is the incorporation of nutrient within the mixture as opposed to being modeled with an auxiliary reaction-diffusion equation. The formulation involves systems of highly nonlinear partial differential equations of surface effects through diffuse-interface models. A mixed finite element spatial discretization is developed and implemented to provide numerical results demonstrating the range of solutions this model can produce. A time-stepping algorithm is then presented for this system, which is shown to be first order accurate and energy gradient stable. The results of an array of numerical experiments are presented, which demonstrate a wide range of solutions produced by various choices of model parameters.

  11. Pedagogical Approaches Used by Faculty in Holland's Model Environments: The Role of Environmental Consistency

    Science.gov (United States)

    Smart, John C.; Ethington, Corinna A.; Umbach, Paul D.

    2009-01-01

    This study examines the extent to which faculty members in the disparate academic environments of Holland's theory devote different amounts of time in their classes to alternative pedagogical approaches and whether such differences are comparable for those in "consistent" and "inconsistent" environments. The findings show wide variations in the…

  12. ICFD modeling of final settlers - developing consistent and effective simulation model structures

    DEFF Research Database (Denmark)

    Plósz, Benedek G.; Guyonvarch, Estelle; Ramin, Elham

    Summary of key findings The concept of interpreted computational fluid dynamic (iCFD) modelling and the development methodology are presented (Fig. 1). The 1-D advection-dispersion model along with the statistically generated, meta-model for pseudo-dispersion constitutes the newly developed i...... nine different model structures based on literature (1; 3; 2; 10; 9) and on more recent considerations (Fig. 2a). Validation tests were done using the CFD outputs from extreme scenarios. The most effective model structure (relatively low the sum of square of relative errors, SSRE, and computational...... time) obtained is that in which the XTC is set at the concentration of the layer just below the feed-layer. The feed-layer location is set to the highest location where X>Xin (solids concentration in SST influent). An effective discretization level (computational time/numerical error) is assessed...

  13. Genetic Algorithm-Based Model Order Reduction of Aeroservoelastic Systems with Consistant States

    Science.gov (United States)

    Zhu, Jin; Wang, Yi; Pant, Kapil; Suh, Peter M.; Brenner, Martin J.

    2017-01-01

    This paper presents a model order reduction framework to construct linear parameter-varying reduced-order models of flexible aircraft for aeroservoelasticity analysis and control synthesis in broad two-dimensional flight parameter space. Genetic algorithms are used to automatically determine physical states for reduction and to generate reduced-order models at grid points within parameter space while minimizing the trial-and-error process. In addition, balanced truncation for unstable systems is used in conjunction with the congruence transformation technique to achieve locally optimal realization and weak fulfillment of state consistency across the entire parameter space. Therefore, aeroservoelasticity reduced-order models at any flight condition can be obtained simply through model interpolation. The methodology is applied to the pitch-plant model of the X-56A Multi-Use Technology Testbed currently being tested at NASA Armstrong Flight Research Center for flutter suppression and gust load alleviation. The present studies indicate that the reduced-order model with more than 12× reduction in the number of states relative to the original model is able to accurately predict system response among all input-output channels. The genetic-algorithm-guided approach exceeds manual and empirical state selection in terms of efficiency and accuracy. The interpolated aeroservoelasticity reduced order models exhibit smooth pole transition and continuously varying gains along a set of prescribed flight conditions, which verifies consistent state representation obtained by congruence transformation. The present model order reduction framework can be used by control engineers for robust aeroservoelasticity controller synthesis and novel vehicle design.

  14. A semi-nonparametric mixture model for selecting functionally consistent proteins.

    Science.gov (United States)

    Yu, Lianbo; Doerge, Rw

    2010-09-28

    High-throughput technologies have led to a new era of proteomics. Although protein microarray experiments are becoming more common place there are a variety of experimental and statistical issues that have yet to be addressed, and that will carry over to new high-throughput technologies unless they are investigated. One of the largest of these challenges is the selection of functionally consistent proteins. We present a novel semi-nonparametric mixture model for classifying proteins as consistent or inconsistent while controlling the false discovery rate and the false non-discovery rate. The performance of the proposed approach is compared to current methods via simulation under a variety of experimental conditions. We provide a statistical method for selecting functionally consistent proteins in the context of protein microarray experiments, but the proposed semi-nonparametric mixture model method can certainly be generalized to solve other mixture data problems. The main advantage of this approach is that it provides the posterior probability of consistency for each protein.

  15. Self-consistent Dark Matter simplified models with an s-channel scalar mediator

    International Nuclear Information System (INIS)

    Bell, Nicole F.; Busoni, Giorgio; Sanderson, Isaac W.

    2017-01-01

    We examine Simplified Models in which fermionic DM interacts with Standard Model (SM) fermions via the exchange of an s -channel scalar mediator. The single-mediator version of this model is not gauge invariant, and instead we must consider models with two scalar mediators which mix and interfere. The minimal gauge invariant scenario involves the mixing of a new singlet scalar with the Standard Model Higgs boson, and is tightly constrained. We construct two Higgs doublet model (2HDM) extensions of this scenario, where the singlet mixes with the 2nd Higgs doublet. Compared with the one doublet model, this provides greater freedom for the masses and mixing angle of the scalar mediators, and their coupling to SM fermions. We outline constraints on these models, and discuss Yukawa structures that allow enhanced couplings, yet keep potentially dangerous flavour violating processes under control. We examine the direct detection phenomenology of these models, accounting for interference of the scalar mediators, and interference of different quarks in the nucleus. Regions of parameter space consistent with direct detection measurements are determined.

  16. Interstellar turbulence model : A self-consistent coupling of plasma and neutral fluids

    International Nuclear Information System (INIS)

    Shaikh, Dastgeer; Zank, Gary P.; Pogorelov, Nikolai

    2006-01-01

    We present results of a preliminary investigation of interstellar turbulence based on a self-consistent two-dimensional fluid simulation model. Our model describes a partially ionized magnetofluid interstellar medium (ISM) that couples a neutral hydrogen fluid to a plasma through charge exchange interactions and assumes that the ISM turbulent correlation scales are much bigger than the shock characteristic length-scales, but smaller than the charge exchange mean free path length-scales. The shocks have no influence on the ISM turbulent fluctuations. We find that nonlinear interactions in coupled plasma-neutral ISM turbulence are influenced substantially by charge exchange processes

  17. Development of a self-consistent lightning NOx simulation in large-scale 3-D models

    Science.gov (United States)

    Luo, Chao; Wang, Yuhang; Koshak, William J.

    2017-03-01

    We seek to develop a self-consistent representation of lightning NOx (LNOx) simulation in a large-scale 3-D model. Lightning flash rates are parameterized functions of meteorological variables related to convection. We examine a suite of such variables and find that convective available potential energy and cloud top height give the best estimates compared to July 2010 observations from ground-based lightning observation networks. Previous models often use lightning NOx vertical profiles derived from cloud-resolving model simulations. An implicit assumption of such an approach is that the postconvection lightning NOx vertical distribution is the same for all deep convection, regardless of geographic location, time of year, or meteorological environment. Detailed observations of the lightning channel segment altitude distribution derived from the NASA Lightning Nitrogen Oxides Model can be used to obtain the LNOx emission profile. Coupling such a profile with model convective transport leads to a more self-consistent lightning distribution compared to using prescribed postconvection profiles. We find that convective redistribution appears to be a more important factor than preconvection LNOx profile selection, providing another reason for linking the strength of convective transport to LNOx distribution.

  18. More hyperelastic models for rubber-like materials: consistent tangent operators and comparative study

    Science.gov (United States)

    Hossain, Mokarram; Steinmann, Paul

    2013-06-01

    Rubber-like materials can deform largely and nonlinearly upon loading, and they return to the initial configuration when the load is removed. Such rubber elasticity is achieved due to very flexible long-chain molecules and a three-dimensional network structure that is formed via cross-linking or entanglements between molecules. Over the years, to model the mechanical behavior of such randomly oriented microstructures, several phenomenological and micromechanically motivated network models for nearly incompressible hyperelastic polymeric materials have been proposed in the literature. To implement these models for polymeric material (undoubtedly with widespread engineering applications) in the finite element framework for solving a boundary value problem, one would require two important ingredients, i.e., the stress tensor and the consistent fourth-order tangent operator, where the latter is the result of linearization of the former. In our previous work, 14 such material models are reviewed by deriving the accurate stress tensors and tangent operators from a group of phenomenological and micromechanical models at large deformations. The current contribution will supplement some further important models that were not included in the previous work. For comparison of all selected models in reproducing the well-known Treloar data, the analytical expressions for the three homogeneous defomation modes, i.e., uniaxial tension, equibiaxial tension, and pure shear, have been derived and the performances of the models are analyzed.

  19. Self-consistent modeling of laminar electrohydrodynamic plumes from ultra-sharp needles in cyclohexane

    Science.gov (United States)

    Becerra, Marley; Frid, Henrik; Vázquez, Pedro A.

    2017-12-01

    This paper presents a self-consistent model of electrohydrodynamic (EHD) laminar plumes produced by electron injection from ultra-sharp needle tips in cyclohexane. Since the density of electrons injected into the liquid is well described by the Fowler-Nordheim field emission theory, the injection law is not assumed. Furthermore, the generation of electrons in cyclohexane and their conversion into negative ions is included in the analysis. Detailed steady-state characteristics of EHD plumes under weak injection and space-charge limited injection are studied. It is found that the plume characteristics far from both electrodes and under weak injection can be accurately described with an asymptotic simplified solution proposed by Vazquez et al. ["Dynamics of electrohydrodynamic laminar plumes: Scaling analysis and integral model," Phys. Fluids 12, 2809 (2000)] when the correct longitudinal electric field distribution and liquid velocity radial profile are used as input. However, this asymptotic solution deviates from the self-consistently calculated plume parameters under space-charge limited injection since it neglects the radial variations of the electric field produced by a high-density charged core. In addition, no significant differences in the model estimates of the plume are found when the simulations are obtained either with the finite element method or with a diffusion-free particle method. It is shown that the model also enables the calculation of the current-voltage characteristic of EHD laminar plumes produced by electron field emission, with good agreement with measured values reported in the literature.

  20. A formally verified algorithm for interactive consistency under a hybrid fault model

    Science.gov (United States)

    Lincoln, Patrick; Rushby, John

    1993-01-01

    Consistent distribution of single-source data to replicated computing channels is a fundamental problem in fault-tolerant system design. The 'Oral Messages' (OM) algorithm solves this problem of Interactive Consistency (Byzantine Agreement) assuming that all faults are worst-cass. Thambidurai and Park introduced a 'hybrid' fault model that distinguished three fault modes: asymmetric (Byzantine), symmetric, and benign; they also exhibited, along with an informal 'proof of correctness', a modified version of OM. Unfortunately, their algorithm is flawed. The discipline of mechanically checked formal verification eventually enabled us to develop a correct algorithm for Interactive Consistency under the hybrid fault model. This algorithm withstands $a$ asymmetric, $s$ symmetric, and $b$ benign faults simultaneously, using $m+1$ rounds, provided $n is greater than 2a + 2s + b + m$, and $m\\geg a$. We present this algorithm, discuss its subtle points, and describe its formal specification and verification in PVS. We argue that formal verification systems such as PVS are now sufficiently effective that their application to fault-tolerance algorithms should be considered routine.

  1. Consistent phase-change modeling for CO2-based heat mining operation

    DEFF Research Database (Denmark)

    Singh, Ashok Kumar; Veje, Christian

    2017-01-01

    –gas phase transition with more accuracy and consistency. Calculation of fluid properties and saturation state were based on the volume translated Peng–Robinson equation of state and results verified. The present model has been applied to a scenario to simulate a CO2-based heat mining process. In this paper......The accuracy of mathematical modeling of phase-change phenomena is limited if a simple, less accurate equation of state completes the governing partial differential equation. However, fluid properties (such as density, dynamic viscosity and compressibility) and saturation state are calculated using...... a highly accurate, complex equation of state. This leads to unstable and inaccurate simulation as the equation of state and governing partial differential equations are mutually inconsistent. In this study, the volume-translated Peng–Robinson equation of state was used with emphasis to model the liquid...

  2. Elastoplastic properties of duplex steel determined using neutron diffraction and self-consistent model

    International Nuclear Information System (INIS)

    Baczmanski, A.; Braham, C.

    2004-01-01

    A new method for determining the parameters characterising elastoplastic deformation of two-phase material is proposed. The method is based on the results of neutron diffraction and mechanical experiments, which are analysed using the self-consistent rate-independent model of elastoplastic deformation. The neutron diffraction method has been applied to determine the lattice strains and diffraction peak broadening in two-phase austeno-ferritic steel during uniaxial tensile test. The elastoplastic model was used to predict evolution of internal stresses and critical resolved shear stresses. Calculations based on this model were successfully compared with experimental results and the parameters characterising elastoplastic deformation were determined for both phases of duplex steel

  3. A simple and self-consistent geostrophic-force-balance model of the thermohaline circulation with boundary mixing

    Directory of Open Access Journals (Sweden)

    J. Callies

    2012-01-01

    Full Text Available A simple model of the thermohaline circulation (THC is formulated, with the objective to represent explicitly the geostrophic force balance of the basinwide THC. The model comprises advective-diffusive density balances in two meridional-vertical planes located at the eastern and the western walls of a hemispheric sector basin. Boundary mixing constrains vertical motion to lateral boundary layers along these walls. Interior, along-boundary, and zonally integrated meridional flows are in thermal-wind balance. Rossby waves and the absence of interior mixing render isopycnals zonally flat except near the western boundary, constraining meridional flow to the western boundary layer. The model is forced by a prescribed meridional surface density profile.

    This two-plane model reproduces both steady-state density and steady-state THC structures of a primitive-equation model. The solution shows narrow deep sinking at the eastern high latitudes, distributed upwelling at both boundaries, and a western boundary current with poleward surface and equatorward deep flow. The overturning strength has a 2/3-power-law dependence on vertical diffusivity and a 1/3-power-law dependence on the imposed meridional surface density difference. Convective mixing plays an essential role in the two-plane model, ensuring that deep sinking is located at high latitudes. This role of convective mixing is consistent with that in three-dimensional models and marks a sharp contrast with previous two-dimensional models.

    Overall, the two-plane model reproduces crucial features of the THC as simulated in simple-geometry three-dimensional models. At the same time, the model self-consistently makes quantitative a conceptual picture of the three-dimensional THC that hitherto has been expressed either purely qualitatively or not self-consistently.

  4. Commensurate comparisons of models with energy budget observations reveal consistent climate sensitivities

    Science.gov (United States)

    Armour, K.

    2017-12-01

    Global energy budget observations have been widely used to constrain the effective, or instantaneous climate sensitivity (ICS), producing median estimates around 2°C (Otto et al. 2013; Lewis & Curry 2015). A key question is whether the comprehensive climate models used to project future warming are consistent with these energy budget estimates of ICS. Yet, performing such comparisons has proven challenging. Within models, values of ICS robustly vary over time, as surface temperature patterns evolve with transient warming, and are generally smaller than the values of equilibrium climate sensitivity (ECS). Naively comparing values of ECS in CMIP5 models (median of about 3.4°C) to observation-based values of ICS has led to the suggestion that models are overly sensitive. This apparent discrepancy can partially be resolved by (i) comparing observation-based values of ICS to model values of ICS relevant for historical warming (Armour 2017; Proistosescu & Huybers 2017); (ii) taking into account the "efficacies" of non-CO2 radiative forcing agents (Marvel et al. 2015); and (iii) accounting for the sparseness of historical temperature observations and differences in sea-surface temperature and near-surface air temperature over the oceans (Richardson et al. 2016). Another potential source of discrepancy is a mismatch between observed and simulated surface temperature patterns over recent decades, due to either natural variability or model deficiencies in simulating historical warming patterns. The nature of the mismatch is such that simulated patterns can lead to more positive radiative feedbacks (higher ICS) relative to those engendered by observed patterns. The magnitude of this effect has not yet been addressed. Here we outline an approach to perform fully commensurate comparisons of climate models with global energy budget observations that take all of the above effects into account. We find that when apples-to-apples comparisons are made, values of ICS in models are

  5. Group Membership, Group Change, and Intergroup Attitudes: A Recategorization Model Based on Cognitive Consistency Principles

    Directory of Open Access Journals (Sweden)

    Jenny Roth

    2018-04-01

    Full Text Available The present article introduces a model based on cognitive consistency principles to predict how new identities become integrated into the self-concept, with consequences for intergroup attitudes. The model specifies four concepts (self-concept, stereotypes, identification, and group compatibility as associative connections. The model builds on two cognitive principles, balance–congruity and imbalance–dissonance, to predict identification with social groups that people currently belong to, belonged to in the past, or newly belong to. More precisely, the model suggests that the relative strength of self-group associations (i.e., identification depends in part on the (incompatibility of the different social groups. Combining insights into cognitive representation of knowledge, intergroup bias, and explicit/implicit attitude change, we further derive predictions for intergroup attitudes. We suggest that intergroup attitudes alter depending on the relative associative strength between the social groups and the self, which in turn is determined by the (incompatibility between social groups. This model unifies existing models on the integration of social identities into the self-concept by suggesting that basic cognitive mechanisms play an important role in facilitating or hindering identity integration and thus contribute to reducing or increasing intergroup bias.

  6. Are water simulation models consistent with steady-state and ultrafast vibrational spectroscopy experiments?

    International Nuclear Information System (INIS)

    Schmidt, J.R.; Roberts, S.T.; Loparo, J.J.; Tokmakoff, A.; Fayer, M.D.; Skinner, J.L.

    2007-01-01

    Vibrational spectroscopy can provide important information about structure and dynamics in liquids. In the case of liquid water, this is particularly true for isotopically dilute HOD/D 2 O and HOD/H 2 O systems. Infrared and Raman line shapes for these systems were measured some time ago. Very recently, ultrafast three-pulse vibrational echo experiments have been performed on these systems, which provide new, exciting, and important dynamical benchmarks for liquid water. There has been tremendous theoretical effort expended on the development of classical simulation models for liquid water. These models have been parameterized from experimental structural and thermodynamic measurements. The goal of this paper is to determine if representative simulation models are consistent with steady-state, and especially with these new ultrafast, experiments. Such a comparison provides information about the accuracy of the dynamics of these simulation models. We perform this comparison using theoretical methods developed in previous papers, and calculate the experimental observables directly, without making the Condon and cumulant approximations, and taking into account molecular rotation, vibrational relaxation, and finite excitation pulses. On the whole, the simulation models do remarkably well; perhaps the best overall agreement with experiment comes from the SPC/E model

  7. Group Membership, Group Change, and Intergroup Attitudes: A Recategorization Model Based on Cognitive Consistency Principles.

    Science.gov (United States)

    Roth, Jenny; Steffens, Melanie C; Vignoles, Vivian L

    2018-01-01

    The present article introduces a model based on cognitive consistency principles to predict how new identities become integrated into the self-concept, with consequences for intergroup attitudes. The model specifies four concepts (self-concept, stereotypes, identification, and group compatibility) as associative connections. The model builds on two cognitive principles, balance-congruity and imbalance-dissonance, to predict identification with social groups that people currently belong to, belonged to in the past, or newly belong to. More precisely, the model suggests that the relative strength of self-group associations (i.e., identification) depends in part on the (in)compatibility of the different social groups. Combining insights into cognitive representation of knowledge, intergroup bias, and explicit/implicit attitude change, we further derive predictions for intergroup attitudes. We suggest that intergroup attitudes alter depending on the relative associative strength between the social groups and the self, which in turn is determined by the (in)compatibility between social groups. This model unifies existing models on the integration of social identities into the self-concept by suggesting that basic cognitive mechanisms play an important role in facilitating or hindering identity integration and thus contribute to reducing or increasing intergroup bias.

  8. Self-consistent nonlinear transmission line model of standing wave effects in a capacitive discharge

    International Nuclear Information System (INIS)

    Chabert, P.; Raimbault, J.L.; Rax, J.M.; Lieberman, M.A.

    2004-01-01

    It has been shown previously [Lieberman et al., Plasma Sources Sci. Technol. 11, 283 (2002)], using a non-self-consistent model based on solutions of Maxwell's equations, that several electromagnetic effects may compromise capacitive discharge uniformity. Among these, the standing wave effect dominates at low and moderate electron densities when the driving frequency is significantly greater than the usual 13.56 MHz. In the present work, two different global discharge models have been coupled to a transmission line model and used to obtain the self-consistent characteristics of the standing wave effect. An analytical solution for the wavelength λ was derived for the lossless case and compared to the numerical results. For typical plasma etching conditions (pressure 10-100 mTorr), a good approximation of the wavelength is λ/λ 0 ≅40 V 0 1/10 l -1/2 f -2/5 , where λ 0 is the wavelength in vacuum, V 0 is the rf voltage magnitude in volts at the discharge center, l is the electrode spacing in meters, and f the driving frequency in hertz

  9. Achieving consistent multiple daily low-dose Bacillus anthracis spore inhalation exposures in the rabbit model

    Directory of Open Access Journals (Sweden)

    Roy E Barnewall

    2012-06-01

    Full Text Available Repeated low-level exposures to Bacillus anthracis could occur before or after the remediation of an environmental release. This is especially true for persistent agents such as Bacillus anthracis spores, the causative agent of anthrax. Studies were conducted to examine aerosol methods needed for consistent daily low aerosol concentrations to deliver a low-dose (less than 106 colony forming units (CFU of B. anthracis spores and included a pilot feasibility characterization study, acute exposure study, and a multiple fifteen day exposure study. This manuscript focuses on the state-of-the-science aerosol methodologies used to generate and aerosolize consistent daily low aerosol concentrations and resultant low inhalation doses. The pilot feasibility characterization study determined that the aerosol system was consistent and capable of producing very low aerosol concentrations. In the acute, single day exposure experiment, targeted inhaled doses of 1 x 102, 1 x 103, 1 x 104, and 1 x 105 CFU were used. In the multiple daily exposure experiment, rabbits were exposed multiple days to targeted inhaled doses of 1 x 102, 1 x 103, and 1 x 104 CFU. In all studies, targeted inhaled doses remained fairly consistent from rabbit to rabbit and day to day. The aerosol system produced aerosolized spores within the optimal mass median aerodynamic diameter particle size range to reach deep lung alveoli. Consistency of the inhaled dose was aided by monitoring and recording respiratory parameters during the exposure with real-time plethysmography. Overall, the presented results show that the animal aerosol system was stable and highly reproducible between different studies and multiple exposure days.

  10. Consistent and Conservative Model Selection with the Adaptive LASSO in Stationary and Nonstationary Autoregressions

    DEFF Research Database (Denmark)

    Kock, Anders Bredahl

    2016-01-01

    as if only these had been included in the model from the outset. In particular, this implies that it is able to discriminate between stationary and nonstationary autoregressions and it thereby constitutes an addition to the set of unit root tests. Next, and important in practice, we show that choosing...... to perform conservative model selection it has power even against shrinking alternatives of this form and compare it to the plain Lasso....

  11. Quest for consistent modelling of statistical decay of the compound nucleus

    Science.gov (United States)

    Banerjee, Tathagata; Nath, S.; Pal, Santanu

    2018-01-01

    A statistical model description of heavy ion induced fusion-fission reactions is presented where shell effects, collective enhancement of level density, tilting away effect of compound nuclear spin and dissipation are included. It is shown that the inclusion of all these effects provides a consistent picture of fission where fission hindrance is required to explain the experimental values of both pre-scission neutron multiplicities and evaporation residue cross-sections in contrast to some of the earlier works where a fission hindrance is required for pre-scission neutrons but a fission enhancement for evaporation residue cross-sections.

  12. A Consistent Methodology Based Parameter Estimation for a Lactic Acid Bacteria Fermentation Model

    DEFF Research Database (Denmark)

    Spann, Robert; Roca, Christophe; Kold, David

    2017-01-01

    Lactic acid bacteria are used in many industrial applications, e.g. as starter cultures in the dairy industry or as probiotics, and research on their cell production is highly required. A first principles kinetic model was developed to describe and understand the biological, physical, and chemical...... mechanisms in a lactic acid bacteria fermentation. We present here a consistent approach for a methodology based parameter estimation for a lactic acid fermentation. In the beginning, just an initial knowledge based guess of parameters was available and an initial parameter estimation of the complete set...

  13. Comparison of squashing and self-consistent input-output models of quantum feedback

    Science.gov (United States)

    Peřinová, V.; Lukš, A.; Křepelka, J.

    2018-03-01

    The paper (Yanagisawa and Hope, 2010) opens with two ways of analysis of a measurement-based quantum feedback. The scheme of the feedback includes, along with the homodyne detector, a modulator and a beamsplitter, which does not enable one to extract the nonclassical field. In the present scheme, the beamsplitter is replaced by the quantum noise evader, which makes it possible to extract the nonclassical field. We re-approach the comparison of two models related to the same scheme. The first one admits that in the feedback loop between the photon annihilation and creation operators, unusual commutation relations hold. As a consequence, in the feedback loop, squashing of the light occurs. In the second one, the description arrives at the feedback loop via unitary transformations. But it is obvious that the unitary transformation which describes the modulator changes even the annihilation operator of the mode which passes by the modulator which is not natural. The first model could be called "squashing model" and the second one could be named "self-consistent model". Although the predictions of the two models differ only a little and both the ways of analysis have their advantages, they have also their drawbacks and further investigation is possible.

  14. Non local thermodynamic equilibrium self-consistent average atom model for plasma physics

    International Nuclear Information System (INIS)

    Faussurier, G.; Blancard, Ch.; Berthier, E.

    2000-01-01

    A time-dependent collisional-radiative average-atom model is presented to study statistical properties of highly-charged ion plasmas in off-equilibrium conditions. Atomic structure is described either with a screened-hydrogenic model including l-splitting, or by calculating one electron states in a self-consistent average-atom potential. Collisional and radiative excitation/deexcitation and ionization/recombination rats, as well as auto-ionization and dielectronic recombination rates, are formulated within the average-configuration framework. A good agreement with experiment is found for the charge-state distribution of a gold plasma at electron and density temperature equal to 6 x 10 20 cm -3 and 2200 eV. (author)

  15. A self-consistent model for polycrystal deformation. Description and implementation

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, B.; Lorentzen, T.

    1997-04-01

    This report is a manual for the ANSI C implementation of an incremental elastic-plastic rate-insensitive self-consistent polycrystal deformation model based on (Hutchinson 1970). The model is furthermore described in the Ph.D. thesis by Clausen (Clausen 1997). The structure of the main program, sc{sub m}odel.c, and its subroutines are described with flow-charts. Likewise the pre-processor, sc{sub i}ni.c, is described with a flowchart. Default values of all the input parameters are given in the pre-processor, but the user is able to select from other pre-defined values or enter new values. A sample calculation is made and the results are presented as plots and examples of the output files are shown. (au) 4 tabs., 28 ills., 17 refs.

  16. Study of stress localisation in polycrystalline grains using self-consistent modelling and neutron diffraction

    Science.gov (United States)

    Baczmański, A.; Gaj, A.; Le Joncour, L.; Wroński, S.; François, M.; Panicaud, B.; Braham, C.; Paradowska, A. M.

    2012-08-01

    The time-of-flight neutron diffraction technique and the elastoplastic self-consistent model were used to study the behaviour of single and multi-phase materials. Critical resolved shear stresses and hardening parameters in austenitic and austenitic-ferritic steels were found by analysing the evolution of the lattice strains measured during tensile tests. Special attention was paid to the changes of the grain stresses occurring due to transition from elastic to plastic deformation. Using a new method of data analysis, the variation of the stress localisation tensor as a function of macrostress was measured. The experimental results were successfully compared with model predictions for both phases of the duplex steel and also for the austenitic sample.

  17. A model for time-dependent cosmological constant and its consistency with the present Friedmann universe

    Energy Technology Data Exchange (ETDEWEB)

    Novello, M [Centro Brasileiro de Pesquisas Fisicas, Rua Dr Xavier Sigaud 150, Urca 22290-180 Rio de Janeiro, RJ (Brazil); Barcelos-Neto, J [Instituto de Fisica, Universidade Federal do Rio de Janeiro, RJ (Brazil); Salim, J M [Centro Brasileiro de Pesquisas Fisicas, Rua Dr Xavier Sigaud 150, Urca 22290-180 Rio de Janeiro, RJ (Brazil)

    2002-06-07

    We use a model where the cosmological term can be related to the chiral gauge anomaly of a possible quantum scenario of the initial evolution of the universe. We show that this term is compatible with the Friedmann behaviour of the present universe.

  18. Self-consistent modeling of plasma response to impurity spreading from intense localized source

    International Nuclear Information System (INIS)

    Koltunov, Mikhail

    2012-07-01

    Non-hydrogen impurities unavoidably exist in hot plasmas of present fusion devices. They enter it intrinsically, due to plasma interaction with the wall of vacuum vessel, as well as are seeded for various purposes deliberately. Normally, the spots where injected particles enter the plasma are much smaller than its total surface. Under such conditions one has to expect a significant modification of local plasma parameters through various physical mechanisms, which, in turn, affect the impurity spreading. Self-consistent modeling of interaction between impurity and plasma is, therefore, not possible with linear approaches. A model based on the fluid description of electrons, main and impurity ions, and taking into account the plasma quasi-neutrality, Coulomb collisions of background and impurity charged particles, radiation losses, particle transport to bounding surfaces, is elaborated in this work. To describe the impurity spreading and the plasma response self-consistently, fluid equations for the particle, momentum and energy balances of various plasma components are solved by reducing them to ordinary differential equations for the time evolution of several parameters characterizing the solution in principal details: the magnitudes of plasma density and plasma temperatures in the regions of impurity localization and the spatial scales of these regions. The results of calculations for plasma conditions typical in tokamak experiments with impurity injection are presented. A new mechanism for the condensation phenomenon and formation of cold dense plasma structures is proposed.

  19. Thermodynamically Consistent Algorithms for the Solution of Phase-Field Models

    KAUST Repository

    Vignal, Philippe

    2016-02-11

    Phase-field models are emerging as a promising strategy to simulate interfacial phenomena. Rather than tracking interfaces explicitly as done in sharp interface descriptions, these models use a diffuse order parameter to monitor interfaces implicitly. This implicit description, as well as solid physical and mathematical footings, allow phase-field models to overcome problems found by predecessors. Nonetheless, the method has significant drawbacks. The phase-field framework relies on the solution of high-order, nonlinear partial differential equations. Solving these equations entails a considerable computational cost, so finding efficient strategies to handle them is important. Also, standard discretization strategies can many times lead to incorrect solutions. This happens because, for numerical solutions to phase-field equations to be valid, physical conditions such as mass conservation and free energy monotonicity need to be guaranteed. In this work, we focus on the development of thermodynamically consistent algorithms for time integration of phase-field models. The first part of this thesis focuses on an energy-stable numerical strategy developed for the phase-field crystal equation. This model was put forward to model microstructure evolution. The algorithm developed conserves, guarantees energy stability and is second order accurate in time. The second part of the thesis presents two numerical schemes that generalize literature regarding energy-stable methods for conserved and non-conserved phase-field models. The time discretization strategies can conserve mass if needed, are energy-stable, and second order accurate in time. We also develop an adaptive time-stepping strategy, which can be applied to any second-order accurate scheme. This time-adaptive strategy relies on a backward approximation to give an accurate error estimator. The spatial discretization, in both parts, relies on a mixed finite element formulation and isogeometric analysis. The codes are

  20. Consistent modelling of wind turbine noise propagation from source to receiver.

    Science.gov (United States)

    Barlas, Emre; Zhu, Wei Jun; Shen, Wen Zhong; Dag, Kaya O; Moriarty, Patrick

    2017-11-01

    The unsteady nature of wind turbine noise is a major reason for annoyance. The variation of far-field sound pressure levels is not only caused by the continuous change in wind turbine noise source levels but also by the unsteady flow field and the ground characteristics between the turbine and receiver. To take these phenomena into account, a consistent numerical technique that models the sound propagation from the source to receiver is developed. Large eddy simulation with an actuator line technique is employed for the flow modelling and the corresponding flow fields are used to simulate sound generation and propagation. The local blade relative velocity, angle of attack, and turbulence characteristics are input to the sound generation model. Time-dependent blade locations and the velocity between the noise source and receiver are considered within a quasi-3D propagation model. Long-range noise propagation of a 5 MW wind turbine is investigated. Sound pressure level time series evaluated at the source time are studied for varying wind speeds, surface roughness, and ground impedances within a 2000 m radius from the turbine.

  1. Model for ICRF fast wave current drive in self-consistent MHD equilibria

    International Nuclear Information System (INIS)

    Bonoli, P.T.; Englade, R.C.; Porkolab, M.; Fenstermacher, M.E.

    1993-01-01

    Recently, a model for fast wave current drive in the ion cyclotron radio frequency (ICRF) range was incorporated into the current drive and MHD equilibrium code ACCOME. The ACCOME model combines a free boundary solution of the Grad Shafranov equation with the calculation of driven currents due to neutral beam injection, lower hybrid (LH) waves, bootstrap effects, and ICRF fast waves. The equilibrium and current drive packages iterate between each other to obtain an MHD equilibrium which is consistent with the profiles of driven current density. The ICRF current drive package combines a toroidal full-wave code (FISIC) with a parameterization of the current drive efficiency obtained from an adjoint solution of the Fokker Planck equation. The electron absorption calculation in the full-wave code properly accounts for the combined effects of electron Landau damping (ELD) and transit time magnetic pumping (TTMP), assuming a Maxwellian (or bi-Maxwellian) electron distribution function. Furthermore, the current drive efficiency includes the effects of particle trapping, momentum conserving corrections to the background Fokker Planck collision operator, and toroidally induced variations in the parallel wavenumbers of the injected ICRF waves. This model has been used to carry out detailed studies of advanced physics scenarios in the proposed Tokamak Physics Experiment (TPX). Results are shown, for example, which demonstrate the possibility of achieving stable equilibria at high beta and high bootstrap current fraction in TPX. Model results are also shown for the proposed ITER device

  2. A Time-Dependent Λ and G Cosmological Model Consistent with Cosmological Constraints

    Directory of Open Access Journals (Sweden)

    L. Kantha

    2016-01-01

    Full Text Available The prevailing constant Λ-G cosmological model agrees with observational evidence including the observed red shift, Big Bang Nucleosynthesis (BBN, and the current rate of acceleration. It assumes that matter contributes 27% to the current density of the universe, with the rest (73% coming from dark energy represented by the Einstein cosmological parameter Λ in the governing Friedmann-Robertson-Walker equations, derived from Einstein’s equations of general relativity. However, the principal problem is the extremely small value of the cosmological parameter (~10−52 m2. Moreover, the dark energy density represented by Λ is presumed to have remained unchanged as the universe expanded by 26 orders of magnitude. Attempts to overcome this deficiency often invoke a variable Λ-G model. Cosmic constraints from action principles require that either both G and Λ remain time-invariant or both vary in time. Here, we propose a variable Λ-G cosmological model consistent with the latest red shift data, the current acceleration rate, and BBN, provided the split between matter and dark energy is 18% and 82%. Λ decreases (Λ~τ-2, where τ is the normalized cosmic time and G increases (G~τn with cosmic time. The model results depend only on the chosen value of Λ at present and in the far future and not directly on G.

  3. Development of a 3D consistent 1D neutronics model for reactor core simulation

    International Nuclear Information System (INIS)

    Lee, Ki Bog; Joo, Han Gyu; Cho, Byung Oh; Zee, Sung Quun

    2001-02-01

    In this report a 3D consistent 1D model based on nonlinear analytic nodal method is developed to reproduce the 3D results. During the derivation, the current conservation factor (CCF) is introduced which guarantees the same axial neutron currents obtained from the 1D equation as the 3D reference values. Furthermore in order to properly use 1D group constants, a new 1D group constants representation scheme employing tables for the fuel temperature, moderator density and boron concentration is developed and functionalized for the control rod tip position. To test the 1D kinetics model with CCF, several steady state and transient calculations were performed and compared with 3D reference values. The errors of K-eff values were reduced about one tenth when using CCF without significant computational overhead. And the errors of power distribution were decreased to the range of one fifth or tenth at steady state calculation. The 1D kinetics model with CCF and the 1D group constant functionalization employing tables as a function of control rod tip position can provide preciser results at the steady state and transient calculation. Thus it is expected that the 1D kinetics model derived in this report can be used in the safety analysis, reactor real time simulation coupled with system analysis code, operator support system etc.

  4. An analysis of comprehensive health promotion programs' consistency with the systems model of health.

    Science.gov (United States)

    Meek, J

    1993-01-01

    Purpose. The purpose of this article is to report a review and analysis of the concordance between current comprehensive corporate health promotion programs as described in the published literature and the systems model of health and to explore emerging trends in the field of health promotion. Search Methods. MEDLINE, BIOSIS, and PsycINFO searches were conducted from 1985 to 1991, and the bibliographies of articles thus obtained were back searched for additional descriptions of corporate health promotion programs. Inclusive criteria included "comprehensive" corporate programs, published in peer-reviewed journals or books, and descriptions adequate enough to permit coding in the majority of analysis matrix categories. Out of 63 identified programs, 16 met the inclusion criteria; 47 were excluded. A common reason for rejection was the limitation imposed by inadequate program descriptions in the published literature. Major Findings. On average, the comprehensive corporate programs reviewed were initiated between 1984 and 1987 and set in the context of a manufacturing firm with over 10,000 employees. A minority of programs (12.5%) consistently satisfied systems model criteria. The most common category of programs were those which were inconsistent (44%), meeting some of the criteria of a systems model of health promotion, but not all. The mechanistic medical and public health models predominated strongly (63%) with the preeminent goal being individual risk factor modification. Conclusions. The limitations of the published literature do not permit strong conclusions about the number or degree to which current corporate comprehensive programs are concordant with the systems model of health. Although mechanistic models of health predominated, there is evidence that a number of comprehensive programs were inconsistent with the mechanistic model, meeting some of the criteria, but also meeting some systems model criteria. To continue the advancement of health promotion with

  5. Is the thermal-spike model consistent with experimentally determined electron temperature?

    International Nuclear Information System (INIS)

    Ajryan, Eh.A.; Fedorov, A.V.; Kostenko, B.F.

    2000-01-01

    Carbon K-Auger electron spectra from amorphous carbon foils induced by fast heavy ions are theoretically investigated. The high-energy tail of the Auger structure showing a clear projectile charge dependence is analyzed within the thermal-spike model framework as well as in the frame of another model taking into account some kinetic features of the process. A poor comparison results between theoretically and experimentally determined temperatures are suggested to be due to an improper account of double electron excitations or due to shake-up processes which leave the system in a more energetic initial state than a statically screened core hole

  6. Self-consistent field modeling of adsorption from polymer/surfactant mixtures.

    Science.gov (United States)

    Postmus, Bart R; Leermakers, Frans A M; Cohen Stuart, Martien A

    2008-06-01

    We report on the development of a self-consistent field model that describes the competitive adsorption of nonionic alkyl-(ethylene oxide) surfactants and nonionic polymer poly(ethylene oxide) (PEO) from aqueous solutions onto silica. The model explicitly describes the response to the pH and the ionic strength. On an inorganic oxide surface such as silica, the dissociation of the surface depends on the pH. However, salt ions can screen charges on the surface, and hence, the number of dissociated groups also depends on the ionic strength. Furthermore, the solvent quality for the EO groups is a function of the ionic strength. Using our model, we can compute bulk parameters such as the average size of the polymer coil and the surfactant CMC. We can make predictions on the adsorption behavior of either polymers or surfactants, and we have made adsorption isotherms, i.e., calculated the relationship between the surface excess and its corresponding bulk concentration. When we add both polymer and surfactant to our mixture, we can find a surfactant concentration (or, more precisely, a surfactant chemical potential) below which only the polymer will adsorb and above which only the surfactant will adsorb. The corresponding surfactant concentration is called the CSAC. In a first-order approximation, the surfactant chemical potential has the CMC as its upper bound. We can find conditions for which CMC model is to understand the experimental data from one of our previous articles. We managed to explain most, but unfortunately not all, of the experimental trends. At the end of the article we discuss the possibilities for improving the model.

  7. Methodology and consistency of slant and vertical assessments for ionospheric electron content models

    Science.gov (United States)

    Hernández-Pajares, Manuel; Roma-Dollase, David; Krankowski, Andrzej; García-Rigo, Alberto; Orús-Pérez, Raül

    2017-12-01

    A summary of the main concepts on global ionospheric map(s) [hereinafter GIM(s)] of vertical total electron content (VTEC), with special emphasis on their assessment, is presented in this paper. It is based on the experience accumulated during almost two decades of collaborative work in the context of the international global navigation satellite systems (GNSS) service (IGS) ionosphere working group. A representative comparison of the two main assessments of ionospheric electron content models (VTEC-altimeter and difference of Slant TEC, based on independent global positioning system data GPS, dSTEC-GPS) is performed. It is based on 26 GPS receivers worldwide distributed and mostly placed on islands, from the last quarter of 2010 to the end of 2016. The consistency between dSTEC-GPS and VTEC-altimeter assessments for one of the most accurate IGS GIMs (the tomographic-kriging GIM `UQRG' computed by UPC) is shown. Typical error RMS values of 2 TECU for VTEC-altimeter and 0.5 TECU for dSTEC-GPS assessments are found. And, as expected by following a simple random model, there is a significant correlation between both RMS and specially relative errors, mainly evident when large enough number of observations per pass is considered. The authors expect that this manuscript will be useful for new analysis contributor centres and in general for the scientific and technical community interested in simple and truly external ways of validating electron content models of the ionosphere.

  8. The self-consistent field model for Fermi systems with account of three-body interactions

    Directory of Open Access Journals (Sweden)

    Yu.M. Poluektov

    2015-12-01

    Full Text Available On the basis of a microscopic model of self-consistent field, the thermodynamics of the many-particle Fermi system at finite temperatures with account of three-body interactions is built and the quasiparticle equations of motion are obtained. It is shown that the delta-like three-body interaction gives no contribution into the self-consistent field, and the description of three-body forces requires their nonlocality to be taken into account. The spatially uniform system is considered in detail, and on the basis of the developed microscopic approach general formulas are derived for the fermion's effective mass and the system's equation of state with account of contribution from three-body forces. The effective mass and pressure are numerically calculated for the potential of "semi-transparent sphere" type at zero temperature. Expansions of the effective mass and pressure in powers of density are obtained. It is shown that, with account of only pair forces, the interaction of repulsive character reduces the quasiparticle effective mass relative to the mass of a free particle, and the attractive interaction raises the effective mass. The question of thermodynamic stability of the Fermi system is considered and the three-body repulsive interaction is shown to extend the region of stability of the system with the interparticle pair attraction. The quasiparticle energy spectrum is calculated with account of three-body forces.

  9. Self-consistent model of the Rayleigh--Taylor instability in ablatively accelerated laser plasma

    International Nuclear Information System (INIS)

    Bychkov, V.V.; Golberg, S.M.; Liberman, M.A.

    1994-01-01

    A self-consistent approach to the problem of the growth rate of the Rayleigh--Taylor instability in laser accelerated targets is developed. The analytical solution of the problem is obtained by solving the complete system of the hydrodynamical equations which include both thermal conductivity and energy release due to absorption of the laser light. The developed theory provides a rigorous justification for the supplementary boundary condition in the limiting case of the discontinuity model. An analysis of the suppression of the Rayleigh--Taylor instability by the ablation flow is done and it is found that there is a good agreement between the obtained solution and the approximate formula σ = 0.9√gk - 3u 1 k, where g is the acceleration, u 1 is the ablation velocity. This paper discusses different regimes of the ablative stabilization and compares them with previous analytical and numerical works

  10. Thermal states of neutron stars with a consistent model of interior

    Science.gov (United States)

    Fortin, M.; Taranto, G.; Burgio, G. F.; Haensel, P.; Schulze, H.-J.; Zdunik, J. L.

    2018-04-01

    We model the thermal states of both isolated neutron stars and accreting neutron stars in X-ray transients in quiescence and confront them with observations. We use an equation of state calculated using realistic two-body and three-body nucleon interactions, and superfluid nucleon gaps obtained using the same microscopic approach in the BCS approximation. Consistency with low-luminosity accreting neutron stars is obtained, as the direct Urca process is operating in neutron stars with mass larger than 1.1 M⊙ for the employed equation of state. In addition, proton superfluidity and sufficiently weak neutron superfluidity, obtained using a scaling factor for the gaps, are necessary to explain the cooling of middle-aged neutron stars and to obtain a realistic distribution of neutron star masses.

  11. The Consistent Kinetics Porosity (CKP) Model: A Theory for the Mechanical Behavior of Moderately Porous Solids

    Energy Technology Data Exchange (ETDEWEB)

    BRANNON,REBECCA M.

    2000-11-01

    A theory is developed for the response of moderately porous solids (no more than {approximately}20% void space) to high-strain-rate deformations. The model is consistent because each feature is incorporated in a manner that is mathematically compatible with the other features. Unlike simple p-{alpha} models, the onset of pore collapse depends on the amount of shear present. The user-specifiable yield function depends on pressure, effective shear stress, and porosity. The elastic part of the strain rate is linearly related to the stress rate, with nonlinear corrections from changes in the elastic moduli due to pore collapse. Plastically incompressible flow of the matrix material allows pore collapse and an associated macroscopic plastic volume change. The plastic strain rate due to pore collapse/growth is taken normal to the yield surface. If phase transformation and/or pore nucleation are simultaneously occurring, the inelastic strain rate will be non-normal to the yield surface. To permit hardening, the yield stress of matrix material is treated as an internal state variable. Changes in porosity and matrix yield stress naturally cause the yield surface to evolve. The stress, porosity, and all other state variables vary in a consistent manner so that the stress remains on the yield surface throughout any quasistatic interval of plastic deformation. Dynamic loading allows the stress to exceed the yield surface via an overstress ordinary differential equation that is solved in closed form for better numerical accuracy. The part of the stress rate that causes no plastic work (i.e-, the part that has a zero inner product with the stress deviator and the identity tensor) is given by the projection of the elastic stressrate orthogonal to the span of the stress deviator and the identity tensor.The model, which has been numerically implemented in MIG format, has been exercised under a wide array of extremal loading and unloading paths. As will be discussed in a companion

  12. Reconstruction of dynamic image series from undersampled MRI data using data-driven model consistency condition (MOCCO).

    Science.gov (United States)

    Velikina, Julia V; Samsonov, Alexey A

    2015-11-01

    To accelerate dynamic MR imaging through development of a novel image reconstruction technique using low-rank temporal signal models preestimated from training data. We introduce the model consistency condition (MOCCO) technique, which utilizes temporal models to regularize reconstruction without constraining the solution to be low-rank, as is performed in related techniques. This is achieved by using a data-driven model to design a transform for compressed sensing-type regularization. The enforcement of general compliance with the model without excessively penalizing deviating signal allows recovery of a full-rank solution. Our method was compared with a standard low-rank approach utilizing model-based dimensionality reduction in phantoms and patient examinations for time-resolved contrast-enhanced angiography (CE-MRA) and cardiac CINE imaging. We studied the sensitivity of all methods to rank reduction and temporal subspace modeling errors. MOCCO demonstrated reduced sensitivity to modeling errors compared with the standard approach. Full-rank MOCCO solutions showed significantly improved preservation of temporal fidelity and aliasing/noise suppression in highly accelerated CE-MRA (acceleration up to 27) and cardiac CINE (acceleration up to 15) data. MOCCO overcomes several important deficiencies of previously proposed methods based on pre-estimated temporal models and allows high quality image restoration from highly undersampled CE-MRA and cardiac CINE data. © 2014 Wiley Periodicals, Inc.

  13. Assessing the reliability of predictive activity coefficient models for molecules consisting of several functional groups

    Directory of Open Access Journals (Sweden)

    R. P. Gerber

    2013-03-01

    Full Text Available Currently, the most successful predictive models for activity coefficients are those based on functional groups such as UNIFAC. In contrast, these models require a large amount of experimental data for the determination of their parameter matrix. A more recent alternative is the models based on COSMO, for which only a small set of universal parameters must be calibrated. In this work, a recalibrated COSMO-SAC model was compared with the UNIFAC (Do model employing experimental infinite dilution activity coefficient data for 2236 non-hydrogen-bonding binary mixtures at different temperatures. As expected, UNIFAC (Do presented better overall performance, with a mean absolute error of 0.12 ln-units against 0.22 for our COSMO-SAC implementation. However, in cases involving molecules with several functional groups or when functional groups appear in an unusual way, the deviation for UNIFAC was 0.44 as opposed to 0.20 for COSMO-SAC. These results show that COSMO-SAC provides more reliable predictions for multi-functional or more complex molecules, reaffirming its future prospects.

  14. A fast-simplified wheel-rail contact model consistent with perfect plastic materials

    Science.gov (United States)

    Sebès, Michel; Chevalier, Luc; Ayasse, Jean-Bernard; Chollet, Hugues

    2012-09-01

    A method is described which is an extension of rolling contact models with respect to plasticity. This new method, which is an extension of the STRIPES semi-Hertzian (SH) model, has been implemented in a multi-body-system (MBS) package and does not result in a longer execution time than the STRIPES SH model [J.B. Ayasse and H. Chollet, Determination of the wheel-rail contact patch in semi-Hertzian conditions, Veh. Syst. Dyn. 43(3) (2005), pp. 161-172]. High speed of computation is obtained by some hypotheses about the plastic law, the shape of stresses, the locus of the maximum stress and the slip. Plasticity does not change the vehicle behaviour but there is a need for an extension of rolling contact models with respect to plasticity as far as fatigue analysis of rail is concerned: rolling contact fatigue may be addressed via the finite element method (FEM) including material non-linearities, where loads are the contact stresses provided by the post-processing of MBS results [K. Dang Van, M.H. Maitournam, Z. Moumni, and F. Roger, A comprehensive approach for modeling fatigue and fracture of rails, Eng. Fract. Mech. 76 (2009), pp. 2626-2636]. In STRIPES, like in other MBS models, contact stresses may exceed the plastic yield criterion, leading to wrong results in the subsequent FEM analysis. With the proposed method, contact stresses are kept consistent with a perfect plastic law, avoiding these problems. The method is benchmarked versus non-linear FEM in Hertzian geometries. As a consequence of taking plasticity into account, contact patch area is bigger than the elastic one. In accordance with FEM results, a different ellipse aspect ratio than the one predicted by Hertz theory was also found and finally pressure does not exceed the threshold prescribed by the plastic law. The method also provides more exact results with non-Hertzian geometries. The new approach is finally compared with non-linear FEM in a tangent case with a unidirectional load and a complete

  15. Linking lipid architecture to bilayer structure and mechanics using self-consistent field modelling.

    Science.gov (United States)

    Pera, H; Kleijn, J M; Leermakers, F A M

    2014-02-14

    To understand how lipid architecture determines the lipid bilayer structure and its mechanics, we implement a molecularly detailed model that uses the self-consistent field theory. This numerical model accurately predicts parameters such as Helfrichs mean and Gaussian bending modulus kc and k̄ and the preferred monolayer curvature J(0)(m), and also delivers structural membrane properties like the core thickness, and head group position and orientation. We studied how these mechanical parameters vary with system variations, such as lipid tail length, membrane composition, and those parameters that control the lipid tail and head group solvent quality. For the membrane composition, negatively charged phosphatidylglycerol (PG) or zwitterionic, phosphatidylcholine (PC), and -ethanolamine (PE) lipids were used. In line with experimental findings, we find that the values of kc and the area compression modulus kA are always positive. They respond similarly to parameters that affect the core thickness, but differently to parameters that affect the head group properties. We found that the trends for k̄ and J(0)(m) can be rationalised by the concept of Israelachivili's surfactant packing parameter, and that both k̄ and J(0)(m) change sign with relevant parameter changes. Although typically k̄ 0, especially at low ionic strengths. We anticipate that these changes lead to unstable membranes as these become vulnerable to pore formation or disintegration into lipid disks.

  16. Linking lipid architecture to bilayer structure and mechanics using self-consistent field modelling

    International Nuclear Information System (INIS)

    Pera, H.; Kleijn, J. M.; Leermakers, F. A. M.

    2014-01-01

    To understand how lipid architecture determines the lipid bilayer structure and its mechanics, we implement a molecularly detailed model that uses the self-consistent field theory. This numerical model accurately predicts parameters such as Helfrichs mean and Gaussian bending modulus k c and k ¯ and the preferred monolayer curvature J 0 m , and also delivers structural membrane properties like the core thickness, and head group position and orientation. We studied how these mechanical parameters vary with system variations, such as lipid tail length, membrane composition, and those parameters that control the lipid tail and head group solvent quality. For the membrane composition, negatively charged phosphatidylglycerol (PG) or zwitterionic, phosphatidylcholine (PC), and -ethanolamine (PE) lipids were used. In line with experimental findings, we find that the values of k c and the area compression modulus k A are always positive. They respond similarly to parameters that affect the core thickness, but differently to parameters that affect the head group properties. We found that the trends for k ¯ and J 0 m can be rationalised by the concept of Israelachivili's surfactant packing parameter, and that both k ¯ and J 0 m change sign with relevant parameter changes. Although typically k ¯ 0 m ≫0, especially at low ionic strengths. We anticipate that these changes lead to unstable membranes as these become vulnerable to pore formation or disintegration into lipid disks

  17. Deconvolution of experimental data of aggregates using self-consistent polycrystal models

    International Nuclear Information System (INIS)

    Tome, C.N.; Christodoulou, N.; Holt, R.; Woo, C.H.; Lebensohn, R.A.; Turner, P.A.

    1994-01-01

    We present in this work an overview of self-consistent polycrystal models, together with a comprehensive body of work where those models are used to characterize the response of zirconium alloy aggregates under several deformation regimes. In particular, we address here: evolution of internal stresses associated with heat treatments (thermo-elastic regime) and small deformations (elasto-plastic regime); dimensional changes induced by creep and growth during neutron irradiation (visco-elastic regime); texture development associated with forming operations (visco-plastic regime). In each case we emphasize the effect of texture and internal stresses in the observed response of the aggregate, and from the comparison of the predictions with experimental evidence we determine the single crystal properties from the macroscopic response of the polycrystal. The latter approach is particularly useful in the case of zirconium alloys, a material for which it is not possible to grow single crystals and thus directly measure their single crystal properties. Specifically, we infer information concerning: the stress-free lattice parameters and thermal coefficients of the hexagonal crystals; the irradiation creep compliances and growth coefficients; the crystallographic deformation modes and their associated critical stresses. (au) (38 refs.)

  18. Hazard-consistent ground motions generated with a stochastic fault-rupture model

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, Akemi, E-mail: nishida.akemi@jaea.go.jp [Center for Computational Science and e-Systems, Japan Atomic Energy Agency, 178-4-4, Wakashiba, Kashiwa, Chiba 277-0871 (Japan); Igarashi, Sayaka, E-mail: igrsyk00@pub.taisei.co.jp [Technology Center, Taisei Corporation, 344-1 Nase-cho, Totsuka-ku, Yokohama 245-0051 (Japan); Sakamoto, Shigehiro, E-mail: shigehiro.sakamoto@sakura.taisei.co.jp [Technology Center, Taisei Corporation, 344-1 Nase-cho, Totsuka-ku, Yokohama 245-0051 (Japan); Uchiyama, Yasuo, E-mail: yasuo.uchiyama@sakura.taisei.co.jp [Technology Center, Taisei Corporation, 344-1 Nase-cho, Totsuka-ku, Yokohama 245-0051 (Japan); Yamamoto, Yu, E-mail: ymmyu-00@pub.taisei.co.jp [Technology Center, Taisei Corporation, 344-1 Nase-cho, Totsuka-ku, Yokohama 245-0051 (Japan); Muramatsu, Ken, E-mail: kmuramat@tcu.ac.jp [Department of Nuclear Safety Engineering, Tokyo City University, 1-28-1 Tamazutsumi, Setagaya-ku, Tokyo 158-8557 (Japan); Takada, Tsuyoshi, E-mail: takada@load.arch.t.u-tokyo.ac.jp [Department of Architecture, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2015-12-15

    Conventional seismic probabilistic risk assessments (PRAs) of nuclear power plants consist of probabilistic seismic hazard and fragility curves. Even when earthquake ground-motion time histories are required, they are generated to fit specified response spectra, such as uniform hazard spectra at a specified exceedance probability. These ground motions, however, are not directly linked with seismic-source characteristics. In this context, the authors propose a method based on Monte Carlo simulations to generate a set of input ground-motion time histories to develop an advanced PRA scheme that can explain exceedance probability and the sequence of safety-functional loss in a nuclear power plant. These generated ground motions are consistent with seismic hazard at a reference site, and their seismic-source characteristics can be identified in detail. Ground-motion generation is conducted for a reference site, Oarai in Japan, the location of a hypothetical nuclear power plant. A total of 200 ground motions are generated, ranging from 700 to 1100 cm/s{sup 2} peak acceleration, which corresponds to a 10{sup −4} to 10{sup −5} annual exceedance frequency. In the ground-motion generation, seismic sources are selected according to their hazard contribution at the site, and Monte Carlo simulations with stochastic parameters for the seismic-source characteristics are then conducted until ground motions with the target peak acceleration are obtained. These ground motions are selected so that they are consistent with the hazard. Approximately 110,000 simulations were required to generate 200 ground motions with these peak accelerations. Deviations of peak ground motion acceleration generated for 1000–1100 cm/s{sup 2} range from 1.5 to 3.0, where the deviation is evaluated with peak ground motion accelerations generated from the same seismic source. Deviations of 1.0 to 3.0 for stress drops, one of the stochastic parameters of seismic-source characteristics, are required to

  19. A self-consistent model for the Galactic cosmic ray, antiproton and positron spectra

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    In this talk I will present the escape model of Galactic cosmic rays. This model explains the measured cosmic ray spectra of individual groups of nuclei from TeV to EeV energies. It predicts an early transition to extragalactic cosmic rays, in agreement with recent Auger data. The escape model also explains the soft neutrino spectrum 1/E^2.5 found by IceCube in concordance with Fermi gamma-ray data. I will show that within the same model one can explain the excess of positrons and antiprotons above 20 GeV found by PAMELA and AMS-02, the discrepancy in the slopes of the spectra of cosmic ray protons and heavier nuclei in the TeV-PeV energy range and the plateau in cosmic ray dipole anisotropy in the 2-50 TeV energy range by adding the effects of a 2 million year old nearby supernova.

  20. A self-consistent LTE model of a microwave-driven, high-pressure sulfur lamp

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, C.W.; Mullen, J.J.A.M. van der [Department of Applied Physics, Eindhoven University of Technology (Netherlands)]. E-mails: C.W.Johnston@tue.nl; J.J.A.M.v.d.Mullen@tue.nl; Heijden, H.W.P. van der; Janssen, G.M.; Dijk, J. van [Department of Applied Physics, Eindhoven University of Technology (Netherlands)

    2002-02-21

    A one-dimensional LTE model of a microwave-driven sulfur lamp is presented to aid our understanding of the discharge. The energy balance of the lamp is determined by Ohmic input on one hand and transport due to conductive heat transfer and molecular radiation on the other. We discuss the origin of operational trends in the spectrum, present the model and discuss how the material properties of the plasma are determined. Not only are temperature profiles and electric field strengths simulated but also the spectrum of the lamp from 300 to 900 nm under various conditions of input power and lamp filling pressure. We show that simulated spectra demonstrate observed trends and that radiated power increases linearly with input power as is also found from experiment. (author)

  1. Self-consisting modeling of entangled network strands and dangling ends

    DEFF Research Database (Denmark)

    Jensen, Mette Krog; Schieber, Jay D.; Khaliullin, Renat N.

    2009-01-01

    Text of Abstract We seek knowledge about the effect of dangling ends and soluble structures of stoichiometrically imbalanced networks. To interpretate our recent experimental results we seek a molecular model that can predict LVE data. The discrete slip-link model (DSM) has proven to be a robust......, we call this an ideal entangled network (IEN). We simulate monodisperse polypropylene oxide with an average number of entanglements of ~3.8. Such lightly entangled networks show a G0 that is about 24% lower than GN0. This decrease is a result of monomer fluctuations between entanglements...... of dangling ends and soluble structures. Energy dissipation is increased by adding a fraction of dangling ends, wDE, to the ensemble. We find that when wDE=0.6, G0 is about 75% lower than GN0, this suggests that the fraction of network strands, wNS=1-wDE, largely influences the plateau value at low...

  2. Toward self-consistent tectono-magmatic numerical model of rift-to-ridge transition

    Science.gov (United States)

    Gerya, Taras; Bercovici, David; Liao, Jie

    2017-04-01

    Natural data from modern and ancient lithospheric extension systems suggest three-dimensional (3D) character of deformation and complex relationship between magmatism and tectonics during the entire rift-to-ridge transition. Therefore, self-consistent high-resolution 3D magmatic-thermomechanical numerical approaches stand as a minimum complexity requirement for modeling and understanding of this transition. Here we present results from our new high-resolution 3D finite-difference marker-in-cell rift-to-ridge models, which account for magmatic accretion of the crust and use non-linear strain-weakened visco-plastic rheology of rocks that couples brittle/plastic failure and ductile damage caused by grain size reduction. Numerical experiments suggest that nucleation of rifting and ridge-transform patterns are decoupled in both space and time. At intermediate stages, two patterns can coexist and interact, which triggers development of detachment faults, failed rift arms, hyper-extended margins and oblique proto-transforms. En echelon rift patterns typically develop in the brittle upper-middle crust whereas proto-ridge and proto-transform structures nucleate in the lithospheric mantle. These deep proto-structures propagate upward, inter-connect and rotate toward a mature orthogonal ridge-transform patterns on the timescale of millions years during incipient thermal-magmatic accretion of the new oceanic-like lithosphere. Ductile damage of the extending lithospheric mantle caused by grain size reduction assisted by Zenner pinning plays critical role in rift-to-ridge transition by stabilizing detachment faults and transform structures. Numerical results compare well with observations from incipient spreading regions and passive continental margins.

  3. The Devil in the Dark: A Fully Self-Consistent Seismic Model for Venus

    Science.gov (United States)

    Unterborn, C. T.; Schmerr, N. C.; Irving, J. C. E.

    2017-12-01

    The bulk composition and structure of Venus is unknown despite accounting for 40% of the mass of all the terrestrial planets in our Solar System. As we expand the scope of planetary science to include those planets around other stars, the lack of measurements of basic planetary properties such as moment of inertia, core-size and thermal profile for Venus hinders our ability to compare the potential uniqueness of the Earth and our Solar System to other planetary systems. Here we present fully self-consistent, whole-planet density and seismic velocity profiles calculated using the ExoPlex and BurnMan software packages for various potential Venusian compositions. Using these models, we explore the seismological implications of the different thermal and compositional initial conditions, taking into account phase transitions due to changes in pressure, temperature as well as composition. Using mass-radius constraints, we examine both the centre frequencies of normal mode oscillations and the waveforms and travel times of body waves. Seismic phases which interact with the core, phase transitions in the mantle, and shallower parts of Venus are considered. We also consider the detectability and transmission of these seismic waves from within the dense atmosphere of Venus. Our work provides coupled compositional-seismological reference models for the terrestrial planet in our Solar System of which we know the least. Furthermore, these results point to the potential wealth of fundamental scientific insights into Venus and Earth, as well as exoplanets, which could be gained by including a seismometer on future planetary exploration missions to Venus, the devil in the dark.

  4. Self-consistent model of a solid for the description of lattice and magnetic properties

    International Nuclear Information System (INIS)

    Balcerzak, T.; Szałowski, K.; Jaščur, M.

    2017-01-01

    In the paper a self-consistent theoretical description of the lattice and magnetic properties of a model system with magnetoelastic interaction is presented. The dependence of magnetic exchange integrals on the distance between interacting spins is assumed, which couples the magnetic and the lattice subsystem. The framework is based on summation of the Gibbs free energies for the lattice subsystem and magnetic subsystem. On the basis of minimization principle for the Gibbs energy, a set of equations of state for the system is derived. These equations of state combine the parameters describing the elastic properties (relative volume deformation) and the magnetic properties (magnetization changes). The formalism is extensively illustrated with the numerical calculations performed for a system of ferromagnetically coupled spins S=1/2 localized at the sites of simple cubic lattice. In particular, the significant influence of the magnetic subsystem on the elastic properties is demonstrated. It manifests itself in significant modification of such quantities as the relative volume deformation, thermal expansion coefficient or isothermal compressibility, in particular, in the vicinity of the magnetic phase transition. On the other hand, the influence of lattice subsystem on the magnetic one is also evident. It takes, for example, the form of dependence of the critical (Curie) temperature and magnetization itself on the external pressure, which is thoroughly investigated.

  5. A consistent model for the equilibrium thermodynamic functions of partially ionized flibe plasma with Coulomb corrections

    International Nuclear Information System (INIS)

    Zaghloul, Mofreh R.

    2003-01-01

    Flibe (2LiF-BeF2) is a molten salt that has been chosen as the coolant and breeding material in many design studies of the inertial confinement fusion (ICF) chamber. Flibe plasmas are to be generated in the ICF chamber in a wide range of temperatures and densities. These plasmas are more complex than the plasma of any single chemical species. Nevertheless, the composition and thermodynamic properties of the resulting flibe plasmas are needed for the gas dynamics calculations and the determination of other design parameters in the ICF chamber. In this paper, a simple consistent model for determining the detailed plasma composition and thermodynamic functions of high-temperature, fully dissociated and partially ionized flibe gas is presented and used to calculate different thermodynamic properties of interest to fusion applications. The computed properties include the average ionization state; kinetic pressure; internal energy; specific heats; adiabatic exponent, as well as the sound speed. The presented results are computed under the assumptions of local thermodynamic equilibrium (LTE) and electro-neutrality. A criterion for the validity of the LTE assumption is presented and applied to the computed results. Other attempts in the literature are assessed with their implied inaccuracies pointed out and discussed

  6. Magy: Time dependent, multifrequency, self-consistent code for modeling electron beam devices

    International Nuclear Information System (INIS)

    Botton, M.; Antonsen, T.M.; Levush, B.

    1997-01-01

    A new MAGY code is being developed for three dimensional modeling of electron beam devices. The code includes a time dependent multifrequency description of the electromagnetic fields and a self consistent analysis of the electrons. The equations of motion are solved with the electromagnetic fields as driving forces and the resulting trajectories are used as current sources for the fields. The calculations of the electromagnetic fields are based on the waveguide modal representation, which allows the solution of relatively small number of coupled one dimensional partial differential equations for the amplitudes of the modes, instead of the full solution of Maxwell close-quote s equations. Moreover, the basic time scale for updating the electromagnetic fields is the cavity fill time and not the high frequency of the fields. In MAGY, the coupling among the various modes is determined by the waveguide non-uniformity, finite conductivity of the walls, and the sources due to the electron beam. The equations of motion of the electrons are solved assuming that all the electrons traverse the cavity in less than the cavity fill time. Therefore, at each time step, a set of trajectories are calculated with the high frequency and other external fields as the driving forces. The code includes a verity of diagnostics for both electromagnetic fields and particles trajectories. It is simple to operate and requires modest computing resources, thus expected to serve as a design tool. copyright 1997 American Institute of Physics

  7. A fully kinetic, self-consistent particle simulation model of the collisionless plasma--sheath region

    International Nuclear Information System (INIS)

    Procassini, R.J.; Birdsall, C.K.; Morse, E.C.

    1990-01-01

    A fully kinetic particle-in-cell (PIC) model is used to self-consistently determine the steady-state potential profile in a collisionless plasma that contacts a floating, absorbing boundary. To balance the flow of particles to the wall, a distributed source region is used to inject particles into the one-dimensional system. The effect of the particle source distribution function on the source region and collector sheath potential drops, and particle velocity distributions is investigated. The ion source functions proposed by Emmert et al. [Phys. Fluids 23, 803 (1980)] and Bissell and Johnson [Phys. Fluids 30, 779 (1987)] (and various combinations of these) are used for the injection of both ions and electrons. The values of the potential drops obtained from the PIC simulations are compared to those from the theories of Emmert et al., Bissell and Johnson, and Scheuer and Emmert [Phys. Fluids 31, 3645 (1988)], all of which assume that the electron density is related to the plasma potential via the Boltzmann relation. The values of the source region and total potential drop are found to depend on the choice of the electron source function, as well as the ion source function. The question of an infinite electric field at the plasma--sheath interface, which arises in the analyses of Bissell and Johnson and Scheuer and Emmert, is also addressed

  8. Self-consistent model of a solid for the description of lattice and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Balcerzak, T., E-mail: t_balcerzak@uni.lodz.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, ulica Pomorska 149/153, 90-236 Łódź (Poland); Szałowski, K., E-mail: kszalowski@uni.lodz.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, ulica Pomorska 149/153, 90-236 Łódź (Poland); Jaščur, M. [Department of Theoretical Physics and Astrophysics, Faculty of Science, P. J. Šáfárik University, Park Angelinum 9, 041 54 Košice (Slovakia)

    2017-03-15

    In the paper a self-consistent theoretical description of the lattice and magnetic properties of a model system with magnetoelastic interaction is presented. The dependence of magnetic exchange integrals on the distance between interacting spins is assumed, which couples the magnetic and the lattice subsystem. The framework is based on summation of the Gibbs free energies for the lattice subsystem and magnetic subsystem. On the basis of minimization principle for the Gibbs energy, a set of equations of state for the system is derived. These equations of state combine the parameters describing the elastic properties (relative volume deformation) and the magnetic properties (magnetization changes). The formalism is extensively illustrated with the numerical calculations performed for a system of ferromagnetically coupled spins S=1/2 localized at the sites of simple cubic lattice. In particular, the significant influence of the magnetic subsystem on the elastic properties is demonstrated. It manifests itself in significant modification of such quantities as the relative volume deformation, thermal expansion coefficient or isothermal compressibility, in particular, in the vicinity of the magnetic phase transition. On the other hand, the influence of lattice subsystem on the magnetic one is also evident. It takes, for example, the form of dependence of the critical (Curie) temperature and magnetization itself on the external pressure, which is thoroughly investigated.

  9. Consistent negative response of US crops to high temperatures in observations and crop models

    Science.gov (United States)

    Schauberger, Bernhard; Archontoulis, Sotirios; Arneth, Almut; Balkovic, Juraj; Ciais, Philippe; Deryng, Delphine; Elliott, Joshua; Folberth, Christian; Khabarov, Nikolay; Müller, Christoph; Pugh, Thomas A. M.; Rolinski, Susanne; Schaphoff, Sibyll; Schmid, Erwin; Wang, Xuhui; Schlenker, Wolfram; Frieler, Katja

    2017-04-01

    High temperatures are detrimental to crop yields and could lead to global warming-driven reductions in agricultural productivity. To assess future threats, the majority of studies used process-based crop models, but their ability to represent effects of high temperature has been questioned. Here we show that an ensemble of nine crop models reproduces the observed average temperature responses of US maize, soybean and wheat yields. Each day above 30°C diminishes maize and soybean yields by up to 6% under rainfed conditions. Declines observed in irrigated areas, or simulated assuming full irrigation, are weak. This supports the hypothesis that water stress induced by high temperatures causes the decline. For wheat a negative response to high temperature is neither observed nor simulated under historical conditions, since critical temperatures are rarely exceeded during the growing season. In the future, yields are modelled to decline for all three crops at temperatures above 30°C. Elevated CO2 can only weakly reduce these yield losses, in contrast to irrigation.

  10. Multiscale Modeling at Nanointerfaces: Polymer Thin Film Materials Discovery via Thermomechanically Consistent Coarse Graining

    Science.gov (United States)

    Hsu, David D.

    Due to high nanointerfacial area to volume ratio, the properties of "nanoconfined" polymer thin films, blends, and composites become highly altered compared to their bulk homopolymer analogues. Understanding the structure-property mechanisms underlying this effect is an active area of research. However, despite extensive work, a fundamental framework for predicting the local and system-averaged thermomechanical properties as a function of configuration and polymer species has yet to be established. Towards bridging this gap, here, we present a novel, systematic coarse-graining (CG) method which is able to capture quantitatively, the thermomechanical properties of real polymer systems in bulk and in nanoconfined geometries. This method, which we call thermomechanically consistent coarse-graining (TCCG), is a two-bead-per-monomer CG hybrid approach through which bonded interactions are optimized to match the atomistic structure via the Iterative Boltzmann Inversion method (IBI), and nonbonded interactions are tuned to macroscopic targets through parametric studies. We validate the TCCG method by systematically developing coarse-grain models for a group of five specialized methacrylate-based polymers including poly(methyl methacrylate) (PMMA). Good correlation with bulk all-atom (AA) simulations and experiments is found for the temperature-dependent glass transition temperature (Tg) Flory-Fox scaling relationships, self-diffusion coefficients of liquid monomers, and modulus of elasticity. We apply this TCCG method also to bulk polystyrene (PS) using a comparable coarse-grain CG bead mapping strategy. The model demonstrates chain stiffness commensurate with experiments, and we utilize a density-correction term to improve the transferability of the elastic modulus over a 500 K range. Additionally, PS and PMMA models capture the unexplained, characteristically dissimilar scaling of Tg with the thickness of free-standing films as seen in experiments. Using vibrational

  11. Empirical phylogenies and species abundance distributions are consistent with pre-equilibrium dynamics of neutral community models with gene flow

    KAUST Repository

    Bonnet-Lebrun, Anne-Sophie

    2017-03-17

    Community characteristics reflect past ecological and evolutionary dynamics. Here, we investigate whether it is possible to obtain realistically shaped modelled communities - i.e., with phylogenetic trees and species abundance distributions shaped similarly to typical empirical bird and mammal communities - from neutral community models. To test the effect of gene flow, we contrasted two spatially explicit individual-based neutral models: one with protracted speciation, delayed by gene flow, and one with point mutation speciation, unaffected by gene flow. The former produced more realistic communities (shape of phylogenetic tree and species-abundance distribution), consistent with gene flow being a key process in macro-evolutionary dynamics. Earlier models struggled to capture the empirically observed branching tempo in phylogenetic trees, as measured by the gamma statistic. We show that the low gamma values typical of empirical trees can be obtained in models with protracted speciation, in pre-equilibrium communities developing from an initially abundant and widespread species. This was even more so in communities sampled incompletely, particularly if the unknown species are the youngest. Overall, our results demonstrate that the characteristics of empirical communities that we have studied can, to a large extent, be explained through a purely neutral model under pre-equilibrium conditions. This article is protected by copyright. All rights reserved.

  12. An improved cognitive model of the Iowa and Soochow Gambling Tasks with regard to model fitting performance and tests of parameter consistency.

    Science.gov (United States)

    Dai, Junyi; Kerestes, Rebecca; Upton, Daniel J; Busemeyer, Jerome R; Stout, Julie C

    2015-01-01

    The Iowa Gambling Task (IGT) and the Soochow Gambling Task (SGT) are two experience-based risky decision-making tasks for examining decision-making deficits in clinical populations. Several cognitive models, including the expectancy-valence learning (EVL) model and the prospect valence learning (PVL) model, have been developed to disentangle the motivational, cognitive, and response processes underlying the explicit choices in these tasks. The purpose of the current study was to develop an improved model that can fit empirical data better than the EVL and PVL models and, in addition, produce more consistent parameter estimates across the IGT and SGT. Twenty-six opiate users (mean age 34.23; SD 8.79) and 27 control participants (mean age 35; SD 10.44) completed both tasks. Eighteen cognitive models varying in evaluation, updating, and choice rules were fit to individual data and their performances were compared to that of a statistical baseline model to find a best fitting model. The results showed that the model combining the prospect utility function treating gains and losses separately, the decay-reinforcement updating rule, and the trial-independent choice rule performed the best in both tasks. Furthermore, the winning model produced more consistent individual parameter estimates across the two tasks than any of the other models.

  13. An Improved Cognitive Model of the Iowa and Soochow Gambling Tasks With Regard to Model Fitting Performance and Tests of Parameter Consistency

    Directory of Open Access Journals (Sweden)

    Junyi eDai

    2015-03-01

    Full Text Available The Iowa Gambling Task (IGT and the Soochow Gambling Task (SGT are two experience-based risky decision-making tasks for examining decision-making deficits in clinical populations. Several cognitive models, including the expectancy-valence learning model (EVL and the prospect valence learning model (PVL, have been developed to disentangle the motivational, cognitive, and response processes underlying the explicit choices in these tasks. The purpose of the current study was to develop an improved model that can fit empirical data better than the EVL and PVL models and, in addition, produce more consistent parameter estimates across the IGT and SGT. Twenty-six opiate users (mean age 34.23; SD 8.79 and 27 control participants (mean age 35; SD 10.44 completed both tasks. Eighteen cognitive models varying in evaluation, updating, and choice rules were fit to individual data and their performances were compared to that of a statistical baseline model to find a best fitting model. The results showed that the model combining the prospect utility function treating gains and losses separately, the decay-reinforcement updating rule, and the trial-independent choice rule performed the best in both tasks. Furthermore, the winning model produced more consistent individual parameter estimates across the two tasks than any of the other models.

  14. Achieving Consistent Multiple Daily Low-Dose Bacillus anthracis Spore Inhalation Exposures in the Rabbit Model

    Science.gov (United States)

    2012-06-13

    generating , sizing, quan- tifying, and sampling aerosols of inert materials also hold true for bioaerosols , i.e., for aerosolizing materials of...characterization, traditional bioaerosol generation and collection techniques can be employed to achieve consistent and reproducible low-dose expo- sures... generate and aerosolize consistent daily low aerosol concentrations and resultant low inhalation doses to rabbits. The pilot feasibility characterization

  15. Consistent Two-Equation Closure Modelling for Atmospheric Research: Buoyancy and Vegetation Implementations

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Kelly, Mark C.; Leclerc, Monique Y.

    2012-01-01

    A self-consistent two-equation closure treating buoyancy and plant drag effects has been developed, through consideration of the behaviour of the supplementary equation for the length-scale-determining variable in homogeneous turbulent flow. Being consistent with the canonical flow regimes of gri...

  16. Microencapsulation of model oil in wall matrices consisting of SPI and maltodextrins

    Directory of Open Access Journals (Sweden)

    Moshe Rosenberg

    2016-01-01

    Full Text Available Microencapsulation can provide means to entrap, protect and deliver nutritional lipids and related compounds that are susceptible to deterioration. The encapsulation of high lipid loads represents a challenge. The research has investigated the encapsulation by spray drying of a model oil, at a core load of 25–60%, in wall systems consisting of 2.5–10% SPI and 17.5–10% maltodextrin. In general, core-in-wall-emulsions exhibited unimodal PSD and a mean particle diameter < 0.5 µm. Dry microcapsules ranged in diameter from about 5 to less than 50 µm and exhibited only a limited extent of surface indentation. Core domains, in the form of protein-coated droplets, were embedded throughout the wall matrices and no visible cracks connecting these domains with the environment could be detected. Core retention ranged from 72.2 to 95.9% and was significantly affected (p < 0.05 by a combined influence of wall composition and initial core load. Microencapsulation efficiency, MEE, ranged from 25.4 to 91.6% and from 12.4 to 91.4% after 5 and 30 min of extraction, respectively (p < 0.05. MEE was significantly influenced by wall composition, extraction time, initial core load and DE value of the maltodextrins. Results indicated that wall solutions containing as low as 2.5% SPI and 17.5% maltodextrin were very effective as microencapsulating agents for high oil load. Results highlighted the functionality of SPI as microencapsulating agent in food applications and indicated the importance of carefully designing the composition of core-in-wall-emulsions.

  17. Rifalazil and derivative compounds show potent efficacy in a mouse model of H. pylori colonization.

    Science.gov (United States)

    Rothstein, David M; Mullin, Steve; Sirokman, Klari; Söndergaard, Karen L; Johnson, Starrla; Gwathmey, Judith K; van Duzer, John; Murphy, Christopher K

    2008-08-01

    The rifamycin rifalazil (RFZ), and derivatives (NCEs) were efficacious in a mouse model of Helicobacter pylori colonization. Select NCEs were more active in vitro and showed greater efficacy than RFZ. A systemic component contributes to efficacy.

  18. A Thermodynamically-consistent FBA-based Approach to Biogeochemical Reaction Modeling

    Science.gov (United States)

    Shapiro, B.; Jin, Q.

    2015-12-01

    Microbial rates are critical to understanding biogeochemical processes in natural environments. Recently, flux balance analysis (FBA) has been applied to predict microbial rates in aquifers and other settings. FBA is a genome-scale constraint-based modeling approach that computes metabolic rates and other phenotypes of microorganisms. This approach requires a prior knowledge of substrate uptake rates, which is not available for most natural microbes. Here we propose to constrain substrate uptake rates on the basis of microbial kinetics. Specifically, we calculate rates of respiration (and fermentation) using a revised Monod equation; this equation accounts for both the kinetics and thermodynamics of microbial catabolism. Substrate uptake rates are then computed from the rates of respiration, and applied to FBA to predict rates of microbial growth. We implemented this method by linking two software tools, PHREEQC and COBRA Toolbox. We applied this method to acetotrophic methanogenesis by Methanosarcina barkeri, and compared the simulation results to previous laboratory observations. The new method constrains acetate uptake by accounting for the kinetics and thermodynamics of methanogenesis, and predicted well the observations of previous experiments. In comparison, traditional methods of dynamic-FBA constrain acetate uptake on the basis of enzyme kinetics, and failed to reproduce the experimental results. These results show that microbial rate laws may provide a better constraint than enzyme kinetics for applying FBA to biogeochemical reaction modeling.

  19. A Murine Model of Candida glabrata Vaginitis Shows No Evidence of an Inflammatory Immunopathogenic Response.

    Directory of Open Access Journals (Sweden)

    Evelyn E Nash

    Full Text Available Candida glabrata is the second most common organism isolated from women with vulvovaginal candidiasis (VVC, particularly in women with uncontrolled diabetes mellitus. However, mechanisms involved in the pathogenesis of C. glabrata-associated VVC are unknown and have not been studied at any depth in animal models. The objective of this study was to evaluate host responses to infection following efforts to optimize a murine model of C. glabrata VVC. For this, various designs were evaluated for consistent experimental vaginal colonization (i.e., type 1 and type 2 diabetic mice, exogenous estrogen, varying inocula, and co-infection with C. albicans. Upon model optimization, vaginal fungal burden and polymorphonuclear neutrophil (PMN recruitment were assessed longitudinally over 21 days post-inoculation, together with vaginal concentrations of IL-1β, S100A8 alarmin, lactate dehydrogenase (LDH, and in vivo biofilm formation. Consistent and sustained vaginal colonization with C. glabrata was achieved in estrogenized streptozotocin-induced type 1 diabetic mice. Vaginal PMN infiltration was consistently low, with IL-1β, S100A8, and LDH concentrations similar to uninoculated mice. Biofilm formation was not detected in vivo, and co-infection with C. albicans did not induce synergistic immunopathogenic effects. This data suggests that experimental vaginal colonization of C. glabrata is not associated with an inflammatory immunopathogenic response or biofilm formation.

  20. Self-consistent tight-binding model of B and N doping in graphene

    DEFF Research Database (Denmark)

    Pedersen, Thomas Garm; Pedersen, Jesper Goor

    2013-01-01

    . The impurity potential depends sensitively on the impurity occupancy, leading to a self-consistency requirement. We solve this problem using the impurity Green's function and determine the self-consistent local density of states at the impurity site and, thereby, identify acceptor and donor energy resonances.......Boron and nitrogen substitutional impurities in graphene are analyzed using a self-consistent tight-binding approach. An analytical result for the impurity Green's function is derived taking broken electron-hole symmetry into account and validated by comparison to numerical diagonalization...

  1. Assessing the Accuracy and Consistency of Language Proficiency Classification under Competing Measurement Models

    Science.gov (United States)

    Zhang, Bo

    2010-01-01

    This article investigates how measurement models and statistical procedures can be applied to estimate the accuracy of proficiency classification in language testing. The paper starts with a concise introduction of four measurement models: the classical test theory (CTT) model, the dichotomous item response theory (IRT) model, the testlet response…

  2. Complementarity of DM searches in a consistent simplified model: the case of Z{sup ′}

    Energy Technology Data Exchange (ETDEWEB)

    Jacques, Thomas [SISSA and INFN,via Bonomea 265, 34136 Trieste (Italy); Katz, Andrey [Theory Division, CERN,CH-1211 Geneva 23 (Switzerland); Département de Physique Théorique and Center for Astroparticle Physics (CAP),Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland); Morgante, Enrico; Racco, Davide [Département de Physique Théorique and Center for Astroparticle Physics (CAP),Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland); Rameez, Mohamed [Département de Physique Nucléaire et Corpusculaire,Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland); Riotto, Antonio [Département de Physique Théorique and Center for Astroparticle Physics (CAP),Université de Genève, 24 quai Ansermet, CH-1211 Genève 4 (Switzerland)

    2016-10-14

    We analyze the constraints from direct and indirect detection on fermionic Majorana Dark Matter (DM). Because the interaction with the Standard Model (SM) particles is spin-dependent, a priori the constraints that one gets from neutrino telescopes, the LHC, direct and indirect detection experiments are comparable. We study the complementarity of these searches in a particular example, in which a heavy Z{sup ′} mediates the interactions between the SM and the DM. We find that for heavy dark matter indirect detection provides the strongest bounds on this scenario, while IceCube bounds are typically stronger than those from direct detection. The LHC constraints are dominant for smaller dark matter masses. These light masses are less motivated by thermal relic abundance considerations. We show that the dominant annihilation channels of the light DM in the Sun and the Galactic Center are either bb̄ or tt̄, while the heavy DM annihilation is completely dominated by Zh channel. The latter produces a hard neutrino spectrum which has not been previously analyzed. We study the neutrino spectrum yielded by DM and recast IceCube constraints to allow proper comparison with constraints from direct and indirect detection experiments and LHC exclusions.

  3. Complementarity of DM Searches in a Consistent Simplified Model: the Case of Z'

    CERN Document Server

    Jacques, Thomas; Morgante, Enrico; Racco, Davide; Rameez, Mohamed; Riotto, Antonio

    2016-01-01

    We analyze the constraints from direct and indirect detection on fermionic Majorana Dark Matter (DM). Because the interaction with the Standard Model (SM) particles is spin-dependent, a priori the constraints that one gets from neutrino telescopes, the LHC and direct detection experiments are comparable. We study the complementarity of these searches in a particular example, in which a heavy $Z'$ mediates the interactions between the SM and the DM. We find that in most cases IceCube provides the strongest bounds on this scenario, while the LHC constraints are only meaningful for smaller dark matter masses. These light masses are less motivated by thermal relic abundance considerations. We show that the dominant annihilation channels of the light DM in the Sun are either $b \\bar b$ or $t \\bar t$, while the heavy DM annihilation is completely dominated by $Zh$ channel. The latter produces a hard neutrino spectrum which has not been previously analyzed. We study the neutrino spectrum yielded by DM and recast Ice...

  4. Complementarity of DM searches in a consistent simplified model: the case of Z′

    International Nuclear Information System (INIS)

    Jacques, Thomas; Katz, Andrey; Morgante, Enrico; Racco, Davide; Rameez, Mohamed; Riotto, Antonio

    2016-01-01

    We analyze the constraints from direct and indirect detection on fermionic Majorana Dark Matter (DM). Because the interaction with the Standard Model (SM) particles is spin-dependent, a priori the constraints that one gets from neutrino telescopes, the LHC, direct and indirect detection experiments are comparable. We study the complementarity of these searches in a particular example, in which a heavy Z ′ mediates the interactions between the SM and the DM. We find that for heavy dark matter indirect detection provides the strongest bounds on this scenario, while IceCube bounds are typically stronger than those from direct detection. The LHC constraints are dominant for smaller dark matter masses. These light masses are less motivated by thermal relic abundance considerations. We show that the dominant annihilation channels of the light DM in the Sun and the Galactic Center are either bb̄ or tt̄, while the heavy DM annihilation is completely dominated by Zh channel. The latter produces a hard neutrino spectrum which has not been previously analyzed. We study the neutrino spectrum yielded by DM and recast IceCube constraints to allow proper comparison with constraints from direct and indirect detection experiments and LHC exclusions.

  5. Hydrologic consistency as a basis for assessing complexity of monthly water balance models for the continental United States

    Science.gov (United States)

    Martinez, Guillermo F.; Gupta, Hoshin V.

    2011-12-01

    Methods to select parsimonious and hydrologically consistent model structures are useful for evaluating dominance of hydrologic processes and representativeness of data. While information criteria (appropriately constrained to obey underlying statistical assumptions) can provide a basis for evaluating appropriate model complexity, it is not sufficient to rely upon the principle of maximum likelihood (ML) alone. We suggest that one must also call upon a "principle of hydrologic consistency," meaning that selected ML structures and parameter estimates must be constrained (as well as possible) to reproduce desired hydrological characteristics of the processes under investigation. This argument is demonstrated in the context of evaluating the suitability of candidate model structures for lumped water balance modeling across the continental United States, using data from 307 snow-free catchments. The models are constrained to satisfy several tests of hydrologic consistency, a flow space transformation is used to ensure better consistency with underlying statistical assumptions, and information criteria are used to evaluate model complexity relative to the data. The results clearly demonstrate that the principle of consistency provides a sensible basis for guiding selection of model structures and indicate strong spatial persistence of certain model structures across the continental United States. Further work to untangle reasons for model structure predominance can help to relate conceptual model structures to physical characteristics of the catchments, facilitating the task of prediction in ungaged basins.

  6. Studying the Consistency between and within the Student Mental Models for Atomic Structure

    Science.gov (United States)

    Zarkadis, Nikolaos; Papageorgiou, George; Stamovlasis, Dimitrios

    2017-01-01

    Science education research has revealed a number of student mental models for atomic structure, among which, the one based on Bohr's model seems to be the most dominant. The aim of the current study is to investigate the coherence of these models when students apply them for the explanation of a variety of situations. For this purpose, a set of…

  7. A Multi-Model Framework to Achieve Consistent Evaluation of Climate Change Impacts in the United States

    Science.gov (United States)

    Sarofim, M. C.; Martinich, J.; Waldhoff, S.; DeAngelo, B. J.; McFarland, J.; Jantarasami, L.; Shouse, K.; Crimmins, A.; Li, J.

    2014-12-01

    The Climate Change Impacts and Risk Analysis (CIRA) project establishes a new multi-model framework to systematically assess the physical impacts, economic damages, and risks from climate change. The primary goal of this framework is to estimate the degree to which climate change impacts and damages in the United States are avoided or reduced in the 21st century under multiple greenhouse gas (GHG) emissions mitigation scenarios. The first phase of the CIRA project is a modeling exercise that included two integrated assessment models and 15 sectoral models encompassing five broad impacts sectors: water resources, electric power, infrastructure, human health, and ecosystems. Three consistent socioeconomic and climate scenarios are used to analyze the benefits of global GHG mitigation targets: a reference scenario and two policy scenarios with total radiative forcing targets in 2100 of 4.5 W/m2 and 3.7 W/m2. In this exercise, the implications of key uncertainties are explored, including climate sensitivity, climate model, natural variability, and model structures and parameters. This presentation describes the motivations and goals of the CIRA project; the design and academic contribution of the first CIRA modeling exercise; and briefly summarizes several papers published in a special issue of Climatic Change. The results across impact sectors show that GHG mitigation provides benefits to the United States that increase over time, the effects of climate change can be strongly influenced by near-term policy choices, adaptation can reduce net damages, and impacts exhibit spatial and temporal patterns that may inform mitigation and adaptation policy discussions.

  8. Self-consistent field modeling of linear non-ionic micelles

    NARCIS (Netherlands)

    Jodar-Reyes, A.B.; Leermakers, F.A.M.

    2006-01-01

    A self-consistent field theory is used to predict structural, mechanical, and thermodynamical properties of linear micelles of selected nonionic surfactants of the type CnEm. Upon increase in surfactant concentration the sudden micelle shape transition from spherical to cylindrical (second critical

  9. Plasma Processes: A self-consistent kinetic modeling of a 1-D ...

    Indian Academy of Sciences (India)

    A self-consistent kinetic treatment is presented here, where the Boltzmann equation is solved for a particle conserving Krook collision operator. The resulting equations have been implemented numerically. The treatment solves for the entire quasineutral column, making no assumptions about mfp/, where mfp is the ...

  10. Consistent and Clear Reporting of Results from Diverse Modeling Techniques: The A3 Method

    Directory of Open Access Journals (Sweden)

    Scott Fortmann-Roe

    2015-08-01

    Full Text Available The measurement and reporting of model error is of basic importance when constructing models. Here, a general method and an R package, A3, are presented to support the assessment and communication of the quality of a model fit along with metrics of variable importance. The presented method is accurate, robust, and adaptable to a wide range of predictive modeling algorithms. The method is described along with case studies and a usage guide. It is shown how the method can be used to obtain more accurate models for prediction and how this may simultaneously lead to altered inferences and conclusions about the impact of potential drivers within a system.

  11. Self-consistent gyrokinetic modeling of neoclassical and turbulent impurity transport

    OpenAIRE

    Estève , D. ,; Sarazin , Y.; Garbet , X.; Grandgirard , V.; Breton , S. ,; Donnel , P. ,; Asahi , Y. ,; Bourdelle , C.; Dif-Pradalier , G; Ehrlacher , C.; Emeriau , C.; Ghendrih , Ph; Gillot , C.; Latu , G.; Passeron , C.

    2018-01-01

    International audience; Trace impurity transport is studied with the flux-driven gyrokinetic GYSELA code [V. Grandgirard et al., Comp. Phys. Commun. 207, 35 (2016)]. A reduced and linearized multi-species collision operator has been recently implemented, so that both neoclassical and turbulent transport channels can be treated self-consistently on an equal footing. In the Pfirsch-Schlüter regime likely relevant for tungsten, the standard expression of the neoclassical impurity flux is shown t...

  12. The Bioenvironmental modeling of Bahar city based on Climate-consistent Architecture

    OpenAIRE

    Parna Kazemian

    2014-01-01

    The identification of the climate of a particularplace and the analysis of the climatic needs in terms of human comfort and theuse of construction materials is one of the prerequisites of aclimate-consistent design. In studies on climate and weather, usingillustrative reports, first a picture of the state of climate is offered. Then,based on the obtained results, the range of changes is determined, and thecause-effect relationships at different scales are identified. Finally, by ageneral exam...

  13. Self-consistent gyrokinetic modeling of neoclassical and turbulent impurity transport

    Science.gov (United States)

    Estève, D.; Sarazin, Y.; Garbet, X.; Grandgirard, V.; Breton, S.; Donnel, P.; Asahi, Y.; Bourdelle, C.; Dif-Pradalier, G.; Ehrlacher, C.; Emeriau, C.; Ghendrih, Ph.; Gillot, C.; Latu, G.; Passeron, C.

    2018-03-01

    Trace impurity transport is studied with the flux-driven gyrokinetic GYSELA code (Grandgirard et al 2016 Comput. Phys. Commun. 207 35). A reduced and linearized multi-species collision operator has been recently implemented, so that both neoclassical and turbulent transport channels can be treated self-consistently on an equal footing. In the Pfirsch-Schlüter regime that is probably relevant for tungsten, the standard expression for the neoclassical impurity flux is shown to be recovered from gyrokinetics with the employed collision operator. Purely neoclassical simulations of deuterium plasma with trace impurities of helium, carbon and tungsten lead to impurity diffusion coefficients, inward pinch velocities due to density peaking, and thermo-diffusion terms which quantitatively agree with neoclassical predictions and NEO simulations (Belli et al 2012 Plasma Phys. Control. Fusion 54 015015). The thermal screening factor appears to be less than predicted analytically in the Pfirsch-Schlüter regime, which can be detrimental to fusion performance. Finally, self-consistent nonlinear simulations have revealed that the tungsten impurity flux is not the sum of turbulent and neoclassical fluxes computed separately, as is usually assumed. The synergy partly results from the turbulence-driven in-out poloidal asymmetry of tungsten density. This result suggests the need for self-consistent simulations of impurity transport, i.e. including both turbulence and neoclassical physics, in view of quantitative predictions for ITER.

  14. Are the models for type Ia supernova progenitors consistent with the properties of supernova remnants?,

    NARCIS (Netherlands)

    Badenes, C.; Hughes, J.P.; Bravo, E.; Langer, N.

    2007-01-01

    We explore the relationship between the models for progenitor systems of Type Ia supernovae and the properties of the supernova remnants that evolve after the explosion. Most models for Type Ia progenitors in the single-degenerate scenario predict substantial outflows during the presupernova

  15. Physically-consistent wall boundary conditions for the k-ω turbulence model

    DEFF Research Database (Denmark)

    Fuhrman, David R.; Dixen, Martin; Jacobsen, Niels Gjøl

    2010-01-01

    A model solving Reynolds-averaged Navier–Stokes equations, coupled with k-v turbulence closure, is used to simulate steady channel flow on both hydraulically smooth and rough beds. Novel experimental data are used as model validation, with k measured directly from all three components...

  16. CONSISTENT USE OF THE KALMAN FILTER IN CHEMICAL TRANSPORT MODELS (CTMS) FOR DEDUCING EMISSIONS

    Science.gov (United States)

    Past research has shown that emissions can be deduced using observed concentrations of a chemical, a Chemical Transport Model (CTM), and the Kalman filter in an inverse modeling application. An expression was derived for the relationship between the "observable" (i.e., the con...

  17. Hydrological hysteresis and its value for assessing process consistency in catchment conceptual models

    Science.gov (United States)

    O. Fovet; L. Ruiz; M. Hrachowitz; M. Faucheux; C. Gascuel-Odoux

    2015-01-01

    While most hydrological models reproduce the general flow dynamics, they frequently fail to adequately mimic system-internal processes. In particular, the relationship between storage and discharge, which often follows annual hysteretic patterns in shallow hard-rock aquifers, is rarely considered in modelling studies. One main reason is that catchment storage is...

  18. Downscaling CMIP5 climate models shows increased tropical cyclone activity over the 21st century.

    Science.gov (United States)

    Emanuel, Kerry A

    2013-07-23

    A recently developed technique for simulating large [O(10(4))] numbers of tropical cyclones in climate states described by global gridded data is applied to simulations of historical and future climate states simulated by six Coupled Model Intercomparison Project 5 (CMIP5) global climate models. Tropical cyclones downscaled from the climate of the period 1950-2005 are compared with those of the 21st century in simulations that stipulate that the radiative forcing from greenhouse gases increases by over preindustrial values. In contrast to storms that appear explicitly in most global models, the frequency of downscaled tropical cyclones increases during the 21st century in most locations. The intensity of such storms, as measured by their maximum wind speeds, also increases, in agreement with previous results. Increases in tropical cyclone activity are most prominent in the western North Pacific, but are evident in other regions except for the southwestern Pacific. The increased frequency of events is consistent with increases in a genesis potential index based on monthly mean global model output. These results are compared and contrasted with other inferences concerning the effect of global warming on tropical cyclones.

  19. Consistency tests of cosmogonic theories from models of Uranus and Neptune

    Science.gov (United States)

    Podolak, M.; Reynolds, R. T.

    1984-01-01

    The planetary ratios of ice to rock (I/R) abundances expected in Uranus and Neptune are derived on the basis of several cosmogonic theories. For both Uranus and Neptune, the value of I/R lies between about 1.0 and 3.6. This value is difficult to reconcile with a scenario in which N and C are accreted primarily in the form of N2 and CO. It is consistent with some versions of both giant protoplanet theories and equilibrium accretion theories.

  20. Derivation of a Self-Consistent Auroral Oval Model Using the Auroral Boundary Index

    National Research Council Canada - National Science Library

    Anderson, Keith

    2004-01-01

    ... current HF communications capabilities. The auroral morphology is a good indicator of the level at which space weather and its near-Earth consequences are occurring, and thus it is important to develop an auroral prediction model...

  1. Consistent Particle-Continuum Modeling and Simulation of Flows in Strong Thermochemical Nonequilibrium

    Data.gov (United States)

    National Aeronautics and Space Administration — During hypersonic entry into a planetary atmosphere, a spacecraft transitions from free-molecular flow conditions to fully continuum conditions. When modeling and...

  2. A consistent turbulence formulation for the dynamic wake meandering model in the atmospheric boundary layer

    DEFF Research Database (Denmark)

    Keck, Rolf-Erik; Veldkamp, Dick; Wedel-Heinen, Jens Jakob

    as a standalone flow-solver for the velocity and turbulence distribution, and power production in a wind farm. The performance of the standalone implementation is validated against field data, higher-order computational fluid dynamics models, as well as the most common engineering wake models in the wind industry...... evolution 4. atmospheric stability effects on wake deficit evolution and meandering The conducted research is to a large extent based on detailed wake investigations and reference data generated through computational fluid dynamics simulations, where the wind turbine rotor has been represented......This thesis describes the further development and validation of the dynamic meandering wake model for simulating the flow field and power production of wind farms operating in the atmospheric boundary layer (ABL). The overall objective of the conducted research is to improve the modelling...

  3. Thermodynamically consistent modeling of elementary electrochemistry in lithium-ion batteries

    International Nuclear Information System (INIS)

    Colclasure, Andrew M.; Kee, Robert J.

    2010-01-01

    This paper is particularly concerned with the elementary reactions and transport processes that are responsible for Li-ion battery performance. The model generally follows the widely practiced approach developed by Newman and co-workers (e.g., Doyle et al., J. Electrochem. Soc. 140 (1993) 1526 ). However, there are significant departures, especially in modeling electrochemical charge transfer. The present approach introduces systems of microscopically reversible reactions, including both heterogeneous thermal reactions and electrochemical charge-transfer reactions. All reaction rates are evaluated in elementary form, providing a powerful alternative to a Butler-Volmer formalism for the charge-transfer reactions. The paper is particularly concerned with the influence of non-ideal thermodynamics for evaluating reversible potentials as well as charge-transfer rates. The theory and modeling approach establishes a framework for extending chemistry models to incorporate detailed reaction mechanisms that represent multiple competitive reaction pathways.

  4. Consistency Between Convection Allowing Model Output and Passive Microwave Satellite Observations

    Science.gov (United States)

    Bytheway, J. L.; Kummerow, C. D.

    2018-01-01

    Observations from the Global Precipitation Measurement (GPM) core satellite were used along with precipitation forecasts from the High Resolution Rapid Refresh (HRRR) model to assess and interpret differences between observed and modeled storms. Using a feature-based approach, precipitating objects were identified in both the National Centers for Environmental Prediction Stage IV multisensor precipitation product and HRRR forecast at lead times of 1, 2, and 3 h at valid times corresponding to GPM overpasses. Precipitating objects were selected for further study if (a) the observed feature occurred entirely within the swath of the GPM Microwave Imager (GMI) and (b) the HRRR model predicted it at all three forecast lead times. Output from the HRRR model was used to simulate microwave brightness temperatures (Tbs), which were compared to those observed by the GMI. Simulated Tbs were found to have biases at both the warm and cold ends of the distribution, corresponding to the stratiform/anvil and convective areas of the storms, respectively. Several experiments altered both the simulation microphysics and hydrometeor classification in order to evaluate potential shortcomings in the model's representation of precipitating clouds. In general, inconsistencies between observed and simulated brightness temperatures were most improved when transferring snow water content to supercooled liquid hydrometeor classes.

  5. Consistency of Earth Radiation Budget Experiment bidirectional models and the observed anisotropy of reflected sunlight

    Science.gov (United States)

    Baldwin, Daniel G.; Coakley, James A., Jr.

    1991-01-01

    The anisotropy of the radiance field estimated from bidirectional models derived from Nimbus 7 ERB scanner data is compared with the anisotropy observed with the ERB Experiment (ERBE) scanner aboard the ERB satellite. The results of averaging over groups of 40 ERBE scanner scan lines for a period of a month revealed significant differences between the modeled and the observed anisotropy for given scene types and the sun-earth-satellite viewing geometries. By comparing the radiative fluxes derived using the observed anisotropy with those derived assuming isotropic reflection, it is concluded that a reasonable estimate for the maximum error due to the use of incorrect bidirectional models is a bias of about 4 percent for a typical 2.5 deg latitude-longitude monthly mean, and an rms error of 15 percent.

  6. Classifying Multi-Model Wheat Yield Impact Response Surfaces Showing Sensitivity to Temperature and Precipitation Change

    Science.gov (United States)

    Fronzek, Stefan; Pirttioja, Nina; Carter, Timothy R.; Bindi, Marco; Hoffmann, Holger; Palosuo, Taru; Ruiz-Ramos, Margarita; Tao, Fulu; Trnka, Miroslav; Acutis, Marco; hide

    2017-01-01

    Crop growth simulation models can differ greatly in their treatment of key processes and hence in their response to environmental conditions. Here, we used an ensemble of 26 process-based wheat models applied at sites across a European transect to compare their sensitivity to changes in temperature (minus 2 to plus 9 degrees Centigrade) and precipitation (minus 50 to plus 50 percent). Model results were analysed by plotting them as impact response surfaces (IRSs), classifying the IRS patterns of individual model simulations, describing these classes and analysing factors that may explain the major differences in model responses. The model ensemble was used to simulate yields of winter and spring wheat at four sites in Finland, Germany and Spain. Results were plotted as IRSs that show changes in yields relative to the baseline with respect to temperature and precipitation. IRSs of 30-year means and selected extreme years were classified using two approaches describing their pattern. The expert diagnostic approach (EDA) combines two aspects of IRS patterns: location of the maximum yield (nine classes) and strength of the yield response with respect to climate (four classes), resulting in a total of 36 combined classes defined using criteria pre-specified by experts. The statistical diagnostic approach (SDA) groups IRSs by comparing their pattern and magnitude, without attempting to interpret these features. It applies a hierarchical clustering method, grouping response patterns using a distance metric that combines the spatial correlation and Euclidian distance between IRS pairs. The two approaches were used to investigate whether different patterns of yield response could be related to different properties of the crop models, specifically their genealogy, calibration and process description. Although no single model property across a large model ensemble was found to explain the integrated yield response to temperature and precipitation perturbations, the

  7. Investigating the consistency between proxy-based reconstructions and climate models using data assimilation: a mid-Holocene case study

    NARCIS (Netherlands)

    A. Mairesse; H. Goosse; P. Mathiot; H. Wanner; S. Dubinkina (Svetlana)

    2013-01-01

    htmlabstractThe mid-Holocene (6 kyr BP; thousand years before present) is a key period to study the consistency between model results and proxy-based reconstruction data as it corresponds to a standard test for models and a reasonable number of proxy-based records is available. Taking advantage of

  8. A SELF-CONSISTENT MODEL OF THE CIRCUMSTELLAR DEBRIS CREATED BY A GIANT HYPERVELOCITY IMPACT IN THE HD 172555 SYSTEM

    International Nuclear Information System (INIS)

    Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10 19 kg of submicron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at ∼6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4% over the last 27 years, from the Infrared Astronomical Satellite (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that ∼10 47 molecules of SiO vapor are needed to explain an emission feature at ∼8 μm in the Spitzer IRS spectrum of HD 172555. We find that unless there are ∼10 48 atoms or 0.05 M ⊕ of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the ∼8 μm feature can be emission from solid SiO, which naturally occurs in submicron silicate ''smokes'' created by quickly condensing vaporized silicate.

  9. A SELF-CONSISTENT MODEL OF THE CIRCUMSTELLAR DEBRIS CREATED BY A GIANT HYPERVELOCITY IMPACT IN THE HD 172555 SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B. C.; Melosh, H. J. [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Lisse, C. M. [JHU-APL, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Chen, C. H. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Wyatt, M. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Thebault, P. [LESIA, Observatoire de Paris, F-92195 Meudon Principal Cedex (France); Henning, W. G. [NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Gaidos, E. [Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Elkins-Tanton, L. T. [Department of Terrestrial Magnetism, Carnegie Institution for Science, Washington, DC 20015 (United States); Bridges, J. C. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Morlok, A., E-mail: johns477@purdue.edu [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2012-12-10

    Spectral modeling of the large infrared excess in the Spitzer IRS spectra of HD 172555 suggests that there is more than 10{sup 19} kg of submicron dust in the system. Using physical arguments and constraints from observations, we rule out the possibility of the infrared excess being created by a magma ocean planet or a circumplanetary disk or torus. We show that the infrared excess is consistent with a circumstellar debris disk or torus, located at {approx}6 AU, that was created by a planetary scale hypervelocity impact. We find that radiation pressure should remove submicron dust from the debris disk in less than one year. However, the system's mid-infrared photometric flux, dominated by submicron grains, has been stable within 4% over the last 27 years, from the Infrared Astronomical Satellite (1983) to WISE (2010). Our new spectral modeling work and calculations of the radiation pressure on fine dust in HD 172555 provide a self-consistent explanation for this apparent contradiction. We also explore the unconfirmed claim that {approx}10{sup 47} molecules of SiO vapor are needed to explain an emission feature at {approx}8 {mu}m in the Spitzer IRS spectrum of HD 172555. We find that unless there are {approx}10{sup 48} atoms or 0.05 M{sub Circled-Plus} of atomic Si and O vapor in the system, SiO vapor should be destroyed by photo-dissociation in less than 0.2 years. We argue that a second plausible explanation for the {approx}8 {mu}m feature can be emission from solid SiO, which naturally occurs in submicron silicate ''smokes'' created by quickly condensing vaporized silicate.

  10. On the Consistency of Gamma-Ray Burst Spectral Indices with the Synchrotron Shock Model

    Science.gov (United States)

    Preece, R. D.; Briggs, M. S.; Giblin, T. W.; Mallozzi, R. S.; Pendleton, G. N.; Paciesad, W. S.; Band, D. L.

    2002-01-01

    The current scenario for gamma-ray bursts (GRBs) involves internal shocks for the prompt GRB emission phase and external shocks for the afterglow phase. Assuming optically thin synchrotron emission from isotropically distributed energetic shocked electrons, GRB spectra observed with a low-energy power-law spectral index greater than -2/3 (for positive photon number indices E(exp alpha) indicate a problem with this model. For spectra that do not violate this condition, additional tests of the shock model can be made by comparing the low- and high-energy spectral indices, on the basis of the model's assertion that synchrotron emission from a single power-law distribution of electrons is responsible for both the low-energy and the high-energy power-law portions of the spectra. We find in most cases that the inferred relationship between the two spectral indices of observed GRB spectra is inconsistent with the constraints from the simple optically thin synchrotron shock emission model. In this sense, the prompt burst phase is different from the afterglow phase, and this difference may be related to anisotropic distributions of particles or to their continual acceleration in shocks during the prompt phase.

  11. Latent state-trait models for longitudinal family data investigating consistency in perceived support

    NARCIS (Netherlands)

    Loncke, Justine; Mayer, Axel; Eichelsheim, Veroni I.; Branje, Susan J. T.; Meeus, W.H.J.; Koot, Hans M.; Buysse, Ann; Loeys, Tom

    Support is key to healthy family functioning. Using the family social relations model (SRM), it has already been shown that variability in perceived support is mostly attributed to individual perceiver effects. Little is known, however, as to whether those effects are stable or occasion-specific.

  12. Self-consistent semi-analytic models of the first stars

    Science.gov (United States)

    Visbal, Eli; Haiman, Zoltán; Bryan, Greg L.

    2018-01-01

    We have developed a semi-analytic framework to model the large-scale evolution of the first Population III (Pop III) stars and the transition to metal-enriched star formation. Our model follows dark matter halos from cosmological N-body simulations, utilizing their individual merger histories and three-dimensional positions, and applies physically motivated prescriptions for star formation and feedback from Lyman-Werner (LW) radiation, hydrogen ionizing radiation, and external metal enrichment due to supernovae winds. This method is intended to complement analytic studies, which do not include clustering or individual merger histories, and hydrodynamical cosmological simulations, which include detailed physics, but are computationally expensive and have limited dynamic range. Utilizing this technique, we compute the cumulative Pop III and metal-enriched star formation rate density (SFRD) as a function of redshift at z ≥ 20. We find that varying the model parameters leads to significant qualitative changes in the global star formation history. The Pop III star formation efficiency and the delay time between Pop III and subsequent metal-enriched star formation are found to have the largest impact. The effect of clustering (i.e. including the three-dimensional positions of individual halos) on various feedback mechanisms is also investigated. The impact of clustering on LW and ionization feedback is found to be relatively mild in our fiducial model, but can be larger if external metal enrichment can promote metal-enriched star formation over large distances.

  13. Self-consistent semi-analytic models of the first stars

    Science.gov (United States)

    Visbal, Eli; Haiman, Zoltán; Bryan, Greg L.

    2018-04-01

    We have developed a semi-analytic framework to model the large-scale evolution of the first Population III (Pop III) stars and the transition to metal-enriched star formation. Our model follows dark matter haloes from cosmological N-body simulations, utilizing their individual merger histories and three-dimensional positions, and applies physically motivated prescriptions for star formation and feedback from Lyman-Werner (LW) radiation, hydrogen ionizing radiation, and external metal enrichment due to supernovae winds. This method is intended to complement analytic studies, which do not include clustering or individual merger histories, and hydrodynamical cosmological simulations, which include detailed physics, but are computationally expensive and have limited dynamic range. Utilizing this technique, we compute the cumulative Pop III and metal-enriched star formation rate density (SFRD) as a function of redshift at z ≥ 20. We find that varying the model parameters leads to significant qualitative changes in the global star formation history. The Pop III star formation efficiency and the delay time between Pop III and subsequent metal-enriched star formation are found to have the largest impact. The effect of clustering (i.e. including the three-dimensional positions of individual haloes) on various feedback mechanisms is also investigated. The impact of clustering on LW and ionization feedback is found to be relatively mild in our fiducial model, but can be larger if external metal enrichment can promote metal-enriched star formation over large distances.

  14. Application of a Mass-Consistent Wind Model to Chinook Windstorms

    Science.gov (United States)

    1988-06-01

    Meteor., 6, 837--344. Endlich, R. M., F. L. Ludwig, C. M. Bhunralkar, and M. A. Estoque , 1380: A practical method for estimating wind character34szics at...Project 8349, Menlo Park, CA. 94025. Endlich, R. M., F. L. Ludwig, C. M. Bhunralkar, and M. A. Estoque , 1982: A diagnostic model for estimating winds

  15. Consistent stress-strain ductile fracture model as applied to two grades of beryllium

    International Nuclear Information System (INIS)

    Priddy, T.G.; Benzley, S.E.; Ford, L.M.

    1980-01-01

    Published yield and ultimate biaxial stress and strain data for two grades of beryllium are correlated with a more complete method of characterizing macroscopic strain at fracture initiation in ductile materials. Results are compared with those obtained from an exponential, mean stress dependent, model. Simple statistical methods are employed to illustrate the degree of correlation for each method with the experimental data

  16. Thermodynamically consistent modeling and simulation of multi-component two-phase flow with partial miscibility

    KAUST Repository

    Kou, Jisheng

    2017-12-09

    A general diffuse interface model with a realistic equation of state (e.g. Peng-Robinson equation of state) is proposed to describe the multi-component two-phase fluid flow based on the principles of the NVT-based framework which is an attractive alternative recently over the NPT-based framework to model the realistic fluids. The proposed model uses the Helmholtz free energy rather than Gibbs free energy in the NPT-based framework. Different from the classical routines, we combine the first law of thermodynamics and related thermodynamical relations to derive the entropy balance equation, and then we derive a transport equation of the Helmholtz free energy density. Furthermore, by using the second law of thermodynamics, we derive a set of unified equations for both interfaces and bulk phases that can describe the partial miscibility of multiple fluids. A relation between the pressure gradient and chemical potential gradients is established, and this relation leads to a new formulation of the momentum balance equation, which demonstrates that chemical potential gradients become the primary driving force of fluid motion. Moreover, we prove that the proposed model satisfies the total (free) energy dissipation with time. For numerical simulation of the proposed model, the key difficulties result from the strong nonlinearity of Helmholtz free energy density and tight coupling relations between molar densities and velocity. To resolve these problems, we propose a novel convex-concave splitting of Helmholtz free energy density and deal well with the coupling relations between molar densities and velocity through very careful physical observations with a mathematical rigor. We prove that the proposed numerical scheme can preserve the discrete (free) energy dissipation. Numerical tests are carried out to verify the effectiveness of the proposed method.

  17. Consistency of Earth Radiation Budget Experiment bidirectional models and the observed anisotropy of reflected sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, D.G. (Univ. of Colorado, Boulder (USA)); Coakley, J.A. (Oregon State Univ., Corvallis (USA))

    1991-03-20

    The Earth Radiation Budget Experiment (ERBE) uses bidirectional models to estimate radiative fluxes from observed radiances. The anisotropy of the radiance field derived from these models is compared with that observed with the ERBE scanner on the Earth Radiation Budget Satellite (ERBS). The bidirectional models used by ERBE were derived from NIMBUS 7 Earth radiation budget (ERB) scanner observations. Because of probable differences in the radiometric calibrations of the ERB and ERBE scanners and because of differences in their field of view sizes, the authors expect to find systematic differences of a few percent between the NIMBUS 7 ERB-derived radiation field anisotropy and the ERBS scanner-observed anisotropy. The differences expected are small compared with the variability of the anisotropy which arises from the variability in cloud cover allowed to occur within the individual scene types. By averaging over groups of 40 ERBE scanner scan lines (equivalent to an average over approximately 2,000 km) for a period of a month, they detect significant differences between the modeled and observed anisotropy for particular scene types and Sun-Earth-satellite viewing geometries. For a typical 2.5{degree} latitude-longitude region these differences give rise to a bias in the radiative flux that is at least 0.3% for the monthly mean and an rms error that is at least 4% for instantaneous observations. By comparing the fluxes derived using the observed anisotropy with those derived assuming isotropic reflection, they conclude that a reasonable estimate for the maximum error due to the use of incorrect bidirectional models is a bias of approximately 4% for a typical 2.5{degree} latitude-longitude, monthly mean and an rms error of 15%.

  18. A physics-explicit model of bacterial conjugation shows the stabilizing role of the conjugative junction

    OpenAIRE

    Pastuszak, Jakub; Waclaw, Bartlomiej

    2017-01-01

    Conjugation is a process in which bacteria exchange DNA through a physical connection (conjugative junction) between mating cells. Despite its significance for processes such as the spread of antibiotic resistance, the role of physical forces in conjugation is poorly understood. Here we use computer models to show that the conjugative junction not only serves as a link to transfer the DNA but it also mechanically stabilises the mating pair which significantly increases the conjugation rate. W...

  19. Self-Consistent 3D Modeling of Electron Cloud Dynamics and Beam Response

    International Nuclear Information System (INIS)

    Furman, Miguel; Furman, M.A.; Celata, C.M.; Kireeff-Covo, M.; Sonnad, K.G.; Vay, J.-L.; Venturini, M.; Cohen, R.; Friedman, A.; Grote, D.; Molvik, A.; Stoltz, P.

    2007-01-01

    We present recent advances in the modeling of beam electron-cloud dynamics, including surface effects such as secondary electron emission, gas desorption, etc, and volumetric effects such as ionization of residual gas and charge-exchange reactions. Simulations for the HCX facility with the code WARP/POSINST will be described and their validity demonstrated by benchmarks against measurements. The code models a wide range of physical processes and uses a number of novel techniques, including a large-timestep electron mover that smoothly interpolates between direct orbit calculation and guiding-center drift equations, and a new computational technique, based on a Lorentz transformation to a moving frame, that allows the cost of a fully 3D simulation to be reduced to that of a quasi-static approximation

  20. Flood damage: a model for consistent, complete and multipurpose scenarios

    Directory of Open Access Journals (Sweden)

    S. Menoni

    2016-12-01

    implemented in ex post damage assessments, also with the objective of better programming financial resources that will be needed for these types of events in the future. On the other hand, integrated interpretations of flood events are fundamental to adapting and optimizing flood mitigation strategies on the basis of thorough forensic investigation of each event, as corroborated by the implementation of the model in a case study.

  1. A Mind/Brain/Matter Model Consistent with Quantum Physics and UFO phenomena

    Science.gov (United States)

    1979-01-01

    realities of a second type (E.P. Wigr, ,.’ "Two Kinds of Reality," The Monist , Vol. 48, No. 2, April 1964). Note that the modei -eing c dvanced by the...biological organism, including egos of "dead" biosystems. Note also that the wave-packet reduction (collapse of the wave function) is not a relativistically ...new fourth law of logic, which is briefly described and summarized. A new photon interaction model. of quantized observable changc is also presented

  2. A nonlinear mechanics model of bio-inspired hierarchical lattice materials consisting of horseshoe microstructures.

    Science.gov (United States)

    Ma, Qiang; Cheng, Huanyu; Jang, Kyung-In; Luan, Haiwen; Hwang, Keh-Chih; Rogers, John A; Huang, Yonggang; Zhang, Yihui

    2016-05-01

    Development of advanced synthetic materials that can mimic the mechanical properties of non-mineralized soft biological materials has important implications in a wide range of technologies. Hierarchical lattice materials constructed with horseshoe microstructures belong to this class of bio-inspired synthetic materials, where the mechanical responses can be tailored to match the nonlinear J-shaped stress-strain curves of human skins. The underlying relations between the J-shaped stress-strain curves and their microstructure geometry are essential in designing such systems for targeted applications. Here, a theoretical model of this type of hierarchical lattice material is developed by combining a finite deformation constitutive relation of the building block (i.e., horseshoe microstructure), with the analyses of equilibrium and deformation compatibility in the periodical lattices. The nonlinear J-shaped stress-strain curves and Poisson ratios predicted by this model agree very well with results of finite element analyses (FEA) and experiment. Based on this model, analytic solutions were obtained for some key mechanical quantities, e.g., elastic modulus, Poisson ratio, peak modulus, and critical strain around which the tangent modulus increases rapidly. A negative Poisson effect is revealed in the hierarchical lattice with triangular topology, as opposed to a positive Poisson effect in hierarchical lattices with Kagome and honeycomb topologies. The lattice topology is also found to have a strong influence on the stress-strain curve. For the three isotropic lattice topologies (triangular, Kagome and honeycomb), the hierarchical triangular lattice material renders the sharpest transition in the stress-strain curve and relative high stretchability, given the same porosity and arc angle of horseshoe microstructure. Furthermore, a demonstrative example illustrates the utility of the developed model in the rapid optimization of hierarchical lattice materials for

  3. A consistent model for leptogenesis, dark matter and the IceCube signal

    Energy Technology Data Exchange (ETDEWEB)

    Fiorentin, M. Re [School of Physics and Astronomy, University of Southampton,SO17 1BJ Southampton (United Kingdom); Niro, V. [Departamento de Física Teórica, Universidad Autónoma de Madrid,Cantoblanco, E-28049 Madrid (Spain); Instituto de Física Teórica UAM/CSIC,Calle Nicolás Cabrera 13-15, Cantoblanco, E-28049 Madrid (Spain); Fornengo, N. [Dipartimento di Fisica, Università di Torino,via P. Giuria, 1, 10125 Torino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Torino,via P. Giuria, 1, 10125 Torino (Italy)

    2016-11-04

    We discuss a left-right symmetric extension of the Standard Model in which the three additional right-handed neutrinos play a central role in explaining the baryon asymmetry of the Universe, the dark matter abundance and the ultra energetic signal detected by the IceCube experiment. The energy spectrum and neutrino flux measured by IceCube are ascribed to the decays of the lightest right-handed neutrino N{sub 1}, thus fixing its mass and lifetime, while the production of N{sub 1} in the primordial thermal bath occurs via a freeze-in mechanism driven by the additional SU(2){sub R} interactions. The constraints imposed by IceCube and the dark matter abundance allow nonetheless the heavier right-handed neutrinos to realize a standard type-I seesaw leptogenesis, with the B−L asymmetry dominantly produced by the next-to-lightest neutrino N{sub 2}. Further consequences and predictions of the model are that: the N{sub 1} production implies a specific power-law relation between the reheating temperature of the Universe and the vacuum expectation value of the SU(2){sub R} triplet; leptogenesis imposes a lower bound on the reheating temperature of the Universe at 7×10{sup 9} GeV. Additionally, the model requires a vanishing absolute neutrino mass scale m{sub 1}≃0.

  4. Demonstration of a geostatistical approach to physically consistent downscaling of climate modeling simulations

    KAUST Repository

    Jha, Sanjeev Kumar

    2013-01-01

    A downscaling approach based on multiple-point geostatistics (MPS) is presented. The key concept underlying MPS is to sample spatial patterns from within training images, which can then be used in characterizing the relationship between different variables across multiple scales. The approach is used here to downscale climate variables including skin surface temperature (TSK), soil moisture (SMOIS), and latent heat flux (LH). The performance of the approach is assessed by applying it to data derived from a regional climate model of the Murray-Darling basin in southeast Australia, using model outputs at two spatial resolutions of 50 and 10 km. The data used in this study cover the period from 1985 to 2006, with 1985 to 2005 used for generating the training images that define the relationships of the variables across the different spatial scales. Subsequently, the spatial distributions for the variables in the year 2006 are determined at 10 km resolution using the 50 km resolution data as input. The MPS geostatistical downscaling approach reproduces the spatial distribution of TSK, SMOIS, and LH at 10 km resolution with the correct spatial patterns over different seasons, while providing uncertainty estimates through the use of multiple realizations. The technique has the potential to not only bridge issues of spatial resolution in regional and global climate model simulations but also in feature sharpening in remote sensing applications through image fusion, filling gaps in spatial data, evaluating downscaled variables with available remote sensing images, and aggregating/disaggregating hydrological and groundwater variables for catchment studies.

  5. Observable signatures of wind--driven chemistry with a fully consistent three dimensional radiative hydrodynamics model of HD 209458b

    OpenAIRE

    Drummond, Benjamin; Mayne, N. J.; Manners, James; Carter, Aarynn L.; Boutle, Ian A.; Baraffe, Isabelle; Hebrard, Eric; Tremblin, Pascal; Sing, David K.; Amundsen, David S.; Acreman, Dave

    2018-01-01

    We present a study of the effect of wind-driven advection on the chemical composition of hot Jupiter atmospheres using a fully-consistent 3D hydrodynamics, chemistry and radiative transfer code, the Met Office Unified Model (UM). Chemical modelling of exoplanet atmospheres has primarily been restricted to 1D models that cannot account for 3D dynamical processes. In this work we couple a chemical relaxation scheme to the UM to account for the chemical interconversion of methane and carbon mono...

  6. Spectropolarimetric forward modelling of the lines of the Lyman-series using a self-consistent, global, solar coronal model

    Science.gov (United States)

    Khan, A.; Belluzzi, L.; Landi Degl'Innocenti, E.; Fineschi, S.; Romoli, M.

    2011-05-01

    Context. The presence and importance of the coronal magnetic field is illustrated by a wide range of phenomena, such as the abnormally high temperatures of the coronal plasma, the existence of a slow and fast solar wind, the triggering of explosive events such as flares and CMEs. Aims: We investigate the possibility of using the Hanle effect to diagnose the coronal magnetic field by analysing its influence on the linear polarisation, i.e. the rotation of the plane of polarisation and depolarisation. Methods: We analyse the polarisation characteristics of the first three lines of the hydrogen Lyman-series using an axisymmetric, self-consistent, minimum-corona MHD model with relatively low values of the magnetic field (a few Gauss). Results: We find that the Hanle effect in the above-mentioned lines indeed seems to be a valuable tool for analysing the coronal magnetic field. However, great care must be taken when analysing the spectropolarimetry of the Lα line, given that a non-radial solar wind and active regions on the solar disk can mimic the effects of the magnetic field, and, in some cases, even mask them. Similar drawbacks are not found for the Lβ and Lγ lines because they are more sensitive to the magnetic field. We also briefly consider the instrumental requirements needed to perform polarimetric observations for diagnosing the coronal magnetic fields. Conclusions: The combined analysis of the three aforementioned lines could provide an important step towards better constrainting the value of solar coronal magnetic fields.

  7. Self-consistent one-dimensional modelling of x-ray laser plasmas

    International Nuclear Information System (INIS)

    Wan, A.S.; Walling, R.S.; Scott, H.A.; Mayle, R.W.; Osterheld, A.L.

    1992-01-01

    This paper presents the simulation of a planar, one-dimensional expanding Ge x-ray laser plasma using a new code which combines hydrodynamics, laser absorption, and detailed level population calculations within the same simulation. Previously, these simulations were performed in separate steps. We will present the effect of line transfer on gains and excited level populations and compare the line transfer result with simulations using escape probabilities. We will also discuss the impact of different atomic models on the accuracy of our simulation

  8. Stretched-exponential decay functions from a self-consistent model of dielectric relaxation

    International Nuclear Information System (INIS)

    Milovanov, A.V.; Rasmussen, J.J.; Rypdal, K.

    2008-01-01

    There are many materials whose dielectric properties are described by a stretched exponential, the so-called Kohlrausch-Williams-Watts (KWW) relaxation function. Its physical origin and statistical-mechanical foundation have been a matter of debate in the literature. In this Letter we suggest a model of dielectric relaxation, which naturally leads to a stretched exponential decay function. Some essential characteristics of the underlying charge conduction mechanisms are considered. A kinetic description of the relaxation and charge transport processes is proposed in terms of equations with time-fractional derivatives

  9. A Single Neonatal Exposure to BMAA in a Rat Model Produces Neuropathology Consistent with Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Laura Louise Scott

    2017-12-01

    Full Text Available Although cyanobacterial β-N-methylamino-l-alanine (BMAA has been implicated in the development of Alzheimer’s Disease (AD, Parkinson’s Disease (PD and Amyotrophic Lateral Sclerosis (ALS, no BMAA animal model has reproduced all the neuropathology typically associated with these neurodegenerative diseases. We present here a neonatal BMAA model that causes β-amyloid deposition, neurofibrillary tangles of hyper-phosphorylated tau, TDP-43 inclusions, Lewy bodies, microbleeds and microgliosis as well as severe neuronal loss in the hippocampus, striatum, substantia nigra pars compacta, and ventral horn of the spinal cord in rats following a single BMAA exposure. We also report here that BMAA exposure on particularly PND3, but also PND4 and 5, the critical period of neurogenesis in the rodent brain, is substantially more toxic than exposure to BMAA on G14, PND6, 7 and 10 which suggests that BMAA could potentially interfere with neonatal neurogenesis in rats. The observed selective toxicity of BMAA during neurogenesis and, in particular, the observed pattern of neuronal loss observed in BMAA-exposed rats suggest that BMAA elicits its effect by altering dopamine and/or serotonin signaling in rats.

  10. A consistent NPMLE of the joint distribution function with competing risks data under the dependent masking and right-censoring model.

    Science.gov (United States)

    Li, Jiahui; Yu, Qiqing

    2016-01-01

    Dinse (Biometrics, 38:417-431, 1982) provides a special type of right-censored and masked competing risks data and proposes a non-parametric maximum likelihood estimator (NPMLE) and a pseudo MLE of the joint distribution function [Formula: see text] with such data. However, their asymptotic properties have not been studied so far. Under the extention of either the conditional masking probability (CMP) model or the random partition masking (RPM) model (Yu and Li, J Nonparametr Stat 24:753-764, 2012), we show that (1) Dinse's estimators are consistent if [Formula: see text] takes on finitely many values and each point in the support set of [Formula: see text] can be observed; (2) if the failure time is continuous, the NPMLE is not uniquely determined, and the standard approach (which puts weights only on one element in each observed set) leads to an inconsistent NPMLE; (3) in general, Dinse's estimators are not consistent even under the discrete assumption; (4) we construct a consistent NPMLE. The consistency is given under a new model called dependent masking and right-censoring model. The CMP model and the RPM model are indeed special cases of the new model. We compare our estimator to Dinse's estimators through simulation and real data. Simulation study indicates that the consistent NPMLE is a good approximation to the underlying distribution for moderate sample sizes.

  11. Self-consistent Maxwell-Bloch model of quantum-dot photonic-crystal-cavity lasers

    DEFF Research Database (Denmark)

    Cartar, William; Mørk, Jesper; Hughes, Stephen

    2017-01-01

    We present a powerful computational approach to simulate the threshold behavior of photonic-crystal quantum-dot (QD) lasers. Using a finite-difference time-domain (FDTD) technique, Maxwell-Bloch equations representing a system of thousands of statistically independent and randomly positioned two...... on both the passive cavity and active lasers, where the latter show a general increase in the pump threshold for cavity lengths greater than N = 7, and a reduction in the nominal cavity mode volume for increasing amounts of disorder....

  12. Microarray profiling shows distinct differences between primary tumors and commonly used preclinical models in hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Wang, Weining; Iyer, N. Gopalakrishna; Tay, Hsien Ts’ung; Wu, Yonghui; Lim, Tony K. H.; Zheng, Lin; Song, In Chin; Kwoh, Chee Keong; Huynh, Hung; Tan, Patrick O. B.; Chow, Pierce K. H.

    2015-01-01

    Despite advances in therapeutics, outcomes for hepatocellular carcinoma (HCC) remain poor and there is an urgent need for efficacious systemic therapy. Unfortunately, drugs that are successful in preclinical studies often fail in the clinical setting, and we hypothesize that this is due to functional differences between primary tumors and commonly used preclinical models. In this study, we attempt to answer this question by comparing tumor morphology and gene expression profiles between primary tumors, xenografts and HCC cell lines. Hep G2 cell lines and tumor cells from patient tumor explants were subcutaneously (ectopically) injected into the flank and orthotopically into liver parenchyma of Mus Musculus SCID mice. The mice were euthanized after two weeks. RNA was extracted from the tumors, and gene expression profiling was performed using the Gene Chip Human Genome U133 Plus 2.0. Principal component analyses (PCA) and construction of dendrograms were conducted using Partek genomics suite. PCA showed that the commonly used HepG2 cell line model and its xenograft counterparts were vastly different from all fresh primary tumors. Expression profiles of primary tumors were also significantly divergent from their counterpart patient-derived xenograft (PDX) models, regardless of the site of implantation. Xenografts from the same primary tumors were more likely to cluster together regardless of site of implantation, although heat maps showed distinct differences in gene expression profiles between orthotopic and ectopic models. The data presented here challenges the utility of routinely used preclinical models. Models using HepG2 were vastly different from primary tumors and PDXs, suggesting that this is not clinically representative. Surprisingly, site of implantation (orthotopic versus ectopic) resulted in limited impact on gene expression profiles, and in both scenarios xenografts differed significantly from the original primary tumors, challenging the long

  13. 3D self-consistent modeling of a matrix source of negative hydrogen ions.

    Science.gov (United States)

    Tarnev, Kh; Demerdjiev, A; Shivarova, A; Lishev, St

    2016-02-01

    The paper is in the scope of studies on the rf driving of a matrix source of negative hydrogen ions: a matrix of small radius discharges with planar-coil inductive driving and single aperture extraction from each discharge. The results from a three-dimensional model, in which plasma description is coupled to electrodynamics, confirm former conclusion that a single coil driving of the whole matrix by a zigzag coil with an omega-shaped conductor on the bottom of each discharge tube ensures efficient rf power deposition to the plasma. The latter is due to similarities with the rf driving of a single discharge by a single planar coil, shown by the obtained induced current and spatial distribution of the plasma parameters. Distinctions associated with the coil configuration as a single coil for the whole matrix are also discussed.

  14. redGEM: Systematic reduction and analysis of genome-scale metabolic reconstructions for development of consistent core metabolic models.

    Directory of Open Access Journals (Sweden)

    Meric Ataman

    2017-07-01

    Full Text Available Genome-scale metabolic reconstructions have proven to be valuable resources in enhancing our understanding of metabolic networks as they encapsulate all known metabolic capabilities of the organisms from genes to proteins to their functions. However the complexity of these large metabolic networks often hinders their utility in various practical applications. Although reduced models are commonly used for modeling and in integrating experimental data, they are often inconsistent across different studies and laboratories due to different criteria and detail, which can compromise transferability of the findings and also integration of experimental data from different groups. In this study, we have developed a systematic semi-automatic approach to reduce genome-scale models into core models in a consistent and logical manner focusing on the central metabolism or subsystems of interest. The method minimizes the loss of information using an approach that combines graph-based search and optimization methods. The resulting core models are shown to be able to capture key properties of the genome-scale models and preserve consistency in terms of biomass and by-product yields, flux and concentration variability and gene essentiality. The development of these "consistently-reduced" models will help to clarify and facilitate integration of different experimental data to draw new understanding that can be directly extendable to genome-scale models.

  15. Interface Consistency

    DEFF Research Database (Denmark)

    Staunstrup, Jørgen

    1998-01-01

    This paper proposes that Interface Consistency is an important issue for the development of modular designs. Byproviding a precise specification of component interfaces it becomes possible to check that separately developedcomponents use a common interface in a coherent matter thus avoiding a very...... significant source of design errors. Awide range of interface specifications are possible, the simplest form is a syntactical check of parameter types.However, today it is possible to do more sophisticated forms involving semantic checks....

  16. Porcine Esophageal Submucosal Gland Culture Model Shows Capacity for Proliferation and DifferentiationSummary

    Directory of Open Access Journals (Sweden)

    Richard J. von Furstenberg

    2017-11-01

    Full Text Available Background & Aims: Although cells comprising esophageal submucosal glands (ESMGs represent a potential progenitor cell niche, new models are needed to understand their capacity to proliferate and differentiate. By histologic appearance, ESMGs have been associated with both overlying normal squamous epithelium and columnar epithelium. Our aim was to assess ESMG proliferation and differentiation in a 3-dimensional culture model. Methods: We evaluated proliferation in human ESMGs from normal and diseased tissue by proliferating cell nuclear antigen immunohistochemistry. Next, we compared 5-ethynyl-2′-deoxyuridine labeling in porcine ESMGs in vivo before and after esophageal injury with a novel in vitro porcine organoid ESMG model. Microarray analysis of ESMGs in culture was compared with squamous epithelium and fresh ESMGs. Results: Marked proliferation was observed in human ESMGs of diseased tissue. This activated ESMG state was recapitulated after esophageal injury in an in vivo porcine model, ESMGs assumed a ductal appearance with increased proliferation compared with control. Isolated and cultured porcine ESMGs produced buds with actively cycling cells and passaged to form epidermal growth factor–dependent spheroids. These spheroids were highly proliferative and were passaged multiple times. Two phenotypes of spheroids were identified: solid squamous (P63+ and hollow/ductal (cytokeratin 7+. Microarray analysis showed spheroids to be distinct from parent ESMGs and enriched for columnar transcripts. Conclusions: Our results suggest that the activated ESMG state, seen in both human disease and our porcine model, may provide a source of cells to repopulate damaged epithelium in a normal manner (squamous or abnormally (columnar epithelium. This culture model will allow the evaluation of factors that drive ESMGs in the regeneration of injured epithelium. The raw microarray data have been uploaded to the National Center for

  17. Porcine Esophageal Submucosal Gland Culture Model Shows Capacity for Proliferation and Differentiation.

    Science.gov (United States)

    von Furstenberg, Richard J; Li, Joy; Stolarchuk, Christina; Feder, Rachel; Campbell, Alexa; Kruger, Leandi; Gonzalez, Liara M; Blikslager, Anthony T; Cardona, Diana M; McCall, Shannon J; Henning, Susan J; Garman, Katherine S

    2017-11-01

    Although cells comprising esophageal submucosal glands (ESMGs) represent a potential progenitor cell niche, new models are needed to understand their capacity to proliferate and differentiate. By histologic appearance, ESMGs have been associated with both overlying normal squamous epithelium and columnar epithelium. Our aim was to assess ESMG proliferation and differentiation in a 3-dimensional culture model. We evaluated proliferation in human ESMGs from normal and diseased tissue by proliferating cell nuclear antigen immunohistochemistry. Next, we compared 5-ethynyl-2'-deoxyuridine labeling in porcine ESMGs in vivo before and after esophageal injury with a novel in vitro porcine organoid ESMG model. Microarray analysis of ESMGs in culture was compared with squamous epithelium and fresh ESMGs. Marked proliferation was observed in human ESMGs of diseased tissue. This activated ESMG state was recapitulated after esophageal injury in an in vivo porcine model, ESMGs assumed a ductal appearance with increased proliferation compared with control. Isolated and cultured porcine ESMGs produced buds with actively cycling cells and passaged to form epidermal growth factor-dependent spheroids. These spheroids were highly proliferative and were passaged multiple times. Two phenotypes of spheroids were identified: solid squamous (P63+) and hollow/ductal (cytokeratin 7+). Microarray analysis showed spheroids to be distinct from parent ESMGs and enriched for columnar transcripts. Our results suggest that the activated ESMG state, seen in both human disease and our porcine model, may provide a source of cells to repopulate damaged epithelium in a normal manner (squamous) or abnormally (columnar epithelium). This culture model will allow the evaluation of factors that drive ESMGs in the regeneration of injured epithelium. The raw microarray data have been uploaded to the National Center for Biotechnology Information Gene Expression Omnibus (accession number: GSE100543).

  18. Small GSK-3 Inhibitor Shows Efficacy in a Motor Neuron Disease Murine Model Modulating Autophagy.

    Directory of Open Access Journals (Sweden)

    Estefanía de Munck

    Full Text Available Amyotrophic lateral sclerosis (ALS is a progressive motor neuron degenerative disease that has no effective treatment up to date. Drug discovery tasks have been hampered due to the lack of knowledge in its molecular etiology together with the limited animal models for research. Recently, a motor neuron disease animal model has been developed using β-N-methylamino-L-alanine (L-BMAA, a neurotoxic amino acid related to the appearing of ALS. In the present work, the neuroprotective role of VP2.51, a small heterocyclic GSK-3 inhibitor, is analysed in this novel murine model together with the analysis of autophagy. VP2.51 daily administration for two weeks, starting the first day after L-BMAA treatment, leads to total recovery of neurological symptoms and prevents the activation of autophagic processes in rats. These results show that the L-BMAA murine model can be used to test the efficacy of new drugs. In addition, the results confirm the therapeutic potential of GSK-3 inhibitors, and specially VP2.51, for the disease-modifying future treatment of motor neuron disorders like ALS.

  19. Human Commercial Models' Eye Colour Shows Negative Frequency-Dependent Selection.

    Directory of Open Access Journals (Sweden)

    Isabela Rodrigues Nogueira Forti

    Full Text Available In this study we investigated the eye colour of human commercial models registered in the UK (400 female and 400 male and Brazil (400 female and 400 male to test the hypothesis that model eye colour frequency was the result of negative frequency-dependent selection. The eye colours of the models were classified as: blue, brown or intermediate. Chi-square analyses of data for countries separated by sex showed that in the United Kingdom brown eyes and intermediate colours were significantly more frequent than expected in comparison to the general United Kingdom population (P<0.001. In Brazil, the most frequent eye colour brown was significantly less frequent than expected in comparison to the general Brazilian population. These results support the hypothesis that model eye colour is the result of negative frequency-dependent selection. This could be the result of people using eye colour as a marker of genetic diversity and finding rarer eye colours more attractive because of the potential advantage more genetically diverse offspring that could result from such a choice. Eye colour may be important because in comparison to many other physical traits (e.g., hair colour it is hard to modify, hide or disguise, and it is highly polymorphic.

  20. Human Commercial Models' Eye Colour Shows Negative Frequency-Dependent Selection.

    Science.gov (United States)

    Forti, Isabela Rodrigues Nogueira; Young, Robert John

    2016-01-01

    In this study we investigated the eye colour of human commercial models registered in the UK (400 female and 400 male) and Brazil (400 female and 400 male) to test the hypothesis that model eye colour frequency was the result of negative frequency-dependent selection. The eye colours of the models were classified as: blue, brown or intermediate. Chi-square analyses of data for countries separated by sex showed that in the United Kingdom brown eyes and intermediate colours were significantly more frequent than expected in comparison to the general United Kingdom population (PBrazilian population. These results support the hypothesis that model eye colour is the result of negative frequency-dependent selection. This could be the result of people using eye colour as a marker of genetic diversity and finding rarer eye colours more attractive because of the potential advantage more genetically diverse offspring that could result from such a choice. Eye colour may be important because in comparison to many other physical traits (e.g., hair colour) it is hard to modify, hide or disguise, and it is highly polymorphic.

  1. Histidine decarboxylase knockout mice, a genetic model of Tourette syndrome, show repetitive grooming after induced fear.

    Science.gov (United States)

    Xu, Meiyu; Li, Lina; Ohtsu, Hiroshi; Pittenger, Christopher

    2015-05-19

    Tics, such as are seen in Tourette syndrome (TS), are common and can cause profound morbidity, but they are poorly understood. Tics are potentiated by psychostimulants, stress, and sleep deprivation. Mutations in the gene histidine decarboxylase (Hdc) have been implicated as a rare genetic cause of TS, and Hdc knockout mice have been validated as a genetic model that recapitulates phenomenological and pathophysiological aspects of the disorder. Tic-like stereotypies in this model have not been observed at baseline but emerge after acute challenge with the psychostimulant d-amphetamine. We tested the ability of an acute stressor to stimulate stereotypies in this model, using tone fear conditioning. Hdc knockout mice acquired conditioned fear normally, as manifested by freezing during the presentation of a tone 48h after it had been paired with a shock. During the 30min following tone presentation, knockout mice showed increased grooming. Heterozygotes exhibited normal freezing and intermediate grooming. These data validate a new paradigm for the examination of tic-like stereotypies in animals without pharmacological challenge and enhance the face validity of the Hdc knockout mouse as a pathophysiologically grounded model of tic disorders. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. MTO1-deficient mouse model mirrors the human phenotype showing complex I defect and cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Lore Becker

    Full Text Available Recently, mutations in the mitochondrial translation optimization factor 1 gene (MTO1 were identified as causative in children with hypertrophic cardiomyopathy, lactic acidosis and respiratory chain defect. Here, we describe an MTO1-deficient mouse model generated by gene trap mutagenesis that mirrors the human phenotype remarkably well. As in patients, the most prominent signs and symptoms were cardiovascular and included bradycardia and cardiomyopathy. In addition, the mutant mice showed a marked worsening of arrhythmias during induction and reversal of anaesthesia. The detailed morphological and biochemical workup of murine hearts indicated that the myocardial damage was due to complex I deficiency and mitochondrial dysfunction. In contrast, neurological examination was largely normal in Mto1-deficient mice. A translational consequence of this mouse model may be to caution against anaesthesia-related cardiac arrhythmias which may be fatal in patients.

  3. A Self-consistent Model of a Ray Through the Orion Complex

    Science.gov (United States)

    Abel, N. P.; Ferland, G. J.

    2003-12-01

    The Orion Complex is the best studied region of active star formation, with observational data available over the entire electromagnetic spectrum. These extensive observations give us a good idea of the physical structure of Orion, that being a thin ( ˜ 0.1 parsec) blister H II region on the face of the molecular cloud OMC-1. A PDR, where the transition from atoms & ions to molecules occurs, forms an interface between the two. Most of the physical processes are driven by starlight from the Trapezium cluster, with the star Ori C being the strongest source of radiation. Observations made towards lines of sight near Ori C reveal numerous H II and molecular line intensities. Photoionization calculations have played an important role in determining the physical properties of the regions where these lines originate, but thus far have treated the H II region and PDR as separate problems. Actually these regions are energized by the same source of radiation, with the gas hydrodynamics providing the physical link between them. Here were present a unified physical model of a single ray through the Orion Complex. We choose a region 60'' west of Ori C, where extensive observations exist. These include lines that originate within the H II region, background PDR, and from regions deep inside OMC-1 itself. An improved treatment of the grain, molecular hydrogen, and CO physics have all been developed as part of the continuing evolution of the plasma code Cloudy, so that we can now simultaneously predict the full spectrum with few free parameters. This provides a holistic approach that will be validated in this well-studied environment then extended to the distant starburst galaxies. Acknowledgements: We thank the NSF and NASA for support.

  4. Ensuring consistency and persistence to the Quality Information Model - The role of the GeoViQua Broker

    Science.gov (United States)

    Bigagli, Lorenzo; Papeschi, Fabrizio; Nativi, Stefano; Bastin, Lucy; Masó, Joan

    2013-04-01

    a few products are annotated with their PID; recent studies show that on a total of about 100000 Clearinghouse products, only 37 have the Product Identifier. Furthermore the association should be persistent within the GeoViQua scope. GeoViQua architecture is built on the brokering approach successfully experimented within the EuroGEOSS project and realized by the GEO DAB (Discovery and Access Broker). Part of the GEOSS Common Infrastructure (GCI), the GEO DAB allows for harmonization and distribution in a transparent way for both users and data providers. This way, GeoViQua can effectively complement and extend the GEO DAB obtaining a Quality-augmentation broker (GeoViQua Broker) which plays a central role in ensuring the consistency of the Producer and User quality models. This work is focused on the typical use case in which the GeoViQua Broker performs data discovery from different data providers, and then integrates in the Quality Information Model the producer quality report with the feedback given by users. In particular, this work highlights the problems faced by the GeoViQua Broker and the techniques adopted to ensure consistency and persistency also for quality reports whose target products are not annotated with a PID. The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under Grant Agreement n° 265178.

  5. Self-consistent modeling of plasma density control using self-excited electron resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Brinkmann, R.P. [Siemens AG, Munich (Germany); Klick, M.; Rehak, W. [Adolf-Slaby Inst., Berlin (Germany)

    1998-12-31

    Plasma processing, such as the structuring of wafer surfaces or the deposition of thin films, plays a pivotal role in the manufacturing of VLSI microelectronics and other semiconductors. Increasing wafer diameters and decreasing device dimensions put an ever-growing demand on the stability of the process conditions. Closed loop feed-back control is thought to ensure this stability, even in the presence of run-to-run variations in the chamber state, or similar drifts in the external process parameters. Traditional plasma diagnostics either provides very indirect plasma information, or causes intolerable disturbances of the process itself. Recently, however, a novel method was proposed which allows to characterize an RF plasma in a strictly passive way. This method, termed Self-Excited Electron Resonance Spectroscopy or SEERS, is based on the excitation of global oscillations in the plasma body due to nonlinearities in the sheath. In this work, the authors study the behavior of an inductively coupled, high density plasma reactor (ICP/HDP) under the action of a SEERS-based closed loop control. The approach employs a period-averaged plasma simulator which allows to predict, for any input power P, the secular evolution of the charge distribution in the plasma bulk, and the spatially resolved capacitance of the boundary sheath. Note that the control scheme is realizable, in the sense that it makes use only of that plasma information which is physically available. The results show that already a simple--even only proportional--SEERS-based feedback control can considerably increase the long time stability of industrial plasma processes.

  6. Models of vertical coordination consistent with the development of bio-energetics

    Directory of Open Access Journals (Sweden)

    Gianluca Nardone

    Full Text Available To foster the development of the biomasses for solid fuel it is fundamental to build up a strategy at a local level in which co-exists farms as well as industrial farms. To such aim, it is necessary to implement an effective vertical coordination between the stakeholders with the definition of a contract that prevents opportunistic behaviors and guarantees the industrial investments of constant supplies over the time. Starting from a project that foresees a biomasses power plant in the south of Italy, this study reflects on the payments to fix in an eventual contract in such a way to maintain the fidelity of the farmers. These one have a greater flexibility since they can choose the most convenient crop. Therefore, their fidelity can be obtained tying the contractual payments to the price of the main alternative crop to the energetic one. The results of the study seem to indicate the opportunity to fix a purchase price of the raw materials linked to the one of durum wheat that is the most widespread crop in the territory and the one that depends more on a volatile market. Using the data of the District 12 of the province of Foggia Water Consortium with an area of 11.300 hectares (instead of the 20.000 demanded in the proposal, it has been possible to organize approximately 600 enterprises in five cluster, each of them identified by a representative farm. With a model of linear programming, we have run different simulations taking into account the possibility to grow sorghum in different ways. Through an aggregation process, it has been calculated that farmers may find it convenient to supply the energetic crop at a price of 50 €/t when the price of durum wheat is 150 €/t. Anyway, this price is lower than the one offered by firm that is planning to build the power plant. Moreover, it has been identified a strong correlation between the price of the durum wheat and the price that makes convenient for the farmers to grow the sorghum. When the

  7. Models of vertical coordination consistent with the development of bio-energetics

    Directory of Open Access Journals (Sweden)

    Rosaria Viscecchia

    2011-02-01

    Full Text Available To foster the development of the biomasses for solid fuel it is fundamental to build up a strategy at a local level in which co-exists farms as well as industrial farms. To such aim, it is necessary to implement an effective vertical coordination between the stakeholders with the definition of a contract that prevents opportunistic behaviors and guarantees the industrial investments of constant supplies over the time. Starting from a project that foresees a biomasses power plant in the south of Italy, this study reflects on the payments to fix in an eventual contract in such a way to maintain the fidelity of the farmers. These one have a greater flexibility since they can choose the most convenient crop. Therefore, their fidelity can be obtained tying the contractual payments to the price of the main alternative crop to the energetic one. The results of the study seem to indicate the opportunity to fix a purchase price of the raw materials linked to the one of durum wheat that is the most widespread crop in the territory and the one that depends more on a volatile market. Using the data of the District 12 of the province of Foggia Water Consortium with an area of 11.300 hectares (instead of the 20.000 demanded in the proposal, it has been possible to organize approximately 600 enterprises in five cluster, each of them identified by a representative farm. With a model of linear programming, we have run different simulations taking into account the possibility to grow sorghum in different ways. Through an aggregation process, it has been calculated that farmers may find it convenient to supply the energetic crop at a price of 50 €/t when the price of durum wheat is 150 €/t. Anyway, this price is lower than the one offered by firm that is planning to build the power plant. Moreover, it has been identified a strong correlation between the price of the durum wheat and the price that makes convenient for the farmers to grow the sorghum. When the

  8. Visual modeling shows that avian host parents use multiple visual cues in rejecting parasitic eggs.

    Science.gov (United States)

    Spottiswoode, Claire N; Stevens, Martin

    2010-05-11

    One of the most striking outcomes of coevolution between species is egg mimicry by brood parasitic birds, resulting from rejection behavior by discriminating host parents. Yet, how exactly does a host detect a parasitic egg? Brood parasitism and egg rejection behavior provide a model system for exploring the relative importance of different visual cues used in a behavioral task. Although hosts are discriminating, we do not know exactly what cues they use, and to answer this it is crucial to account for the receiver's visual perception. Color, luminance ("perceived lightness") and pattern information have never been simultaneously quantified and experimentally tested through a bird's eye. The cuckoo finch Anomalospiza imberbis and its hosts show spectacular polymorphisms in egg appearance, providing a good opportunity for investigating visual discrimination owing to the large range of patterns and colors involved. Here we combine field experiments in Africa with modeling of avian color vision and pattern discrimination to identify the specific visual cues used by hosts in making rejection decisions. We found that disparity between host and foreign eggs in both color and several aspects of pattern (dispersion, principal marking size, and variability in marking size) were important predictors of rejection, especially color. These cues correspond exactly to the principal differences between host and parasitic eggs, showing that hosts use the most reliable available cues in making rejection decisions, and select for parasitic eggs that are increasingly mimetic in a range of visual attributes.

  9. Transchromosomic cell model of Down syndrome shows aberrant migration, adhesion and proteome response to extracellular matrix

    Directory of Open Access Journals (Sweden)

    Cotter Finbarr E

    2009-08-01

    Full Text Available Abstract Background Down syndrome (DS, caused by trisomy of human chromosome 21 (HSA21, is the most common genetic birth defect. Congenital heart defects (CHD are seen in 40% of DS children, and >50% of all atrioventricular canal defects in infancy are caused by trisomy 21, but the causative genes remain unknown. Results Here we show that aberrant adhesion and proliferation of DS cells can be reproduced using a transchromosomic model of DS (mouse fibroblasts bearing supernumerary HSA21. We also demonstrate a deacrease of cell migration in transchromosomic cells independently of their adhesion properties. We show that cell-autonomous proteome response to the presence of Collagen VI in extracellular matrix is strongly affected by trisomy 21. Conclusion This set of experiments establishes a new model system for genetic dissection of the specific HSA21 gene-overdose contributions to aberrant cell migration, adhesion, proliferation and specific proteome response to collagen VI, cellular phenotypes linked to the pathogenesis of CHD.

  10. Self-consistent field modeling of non-ionic surfactants at the silica-water interface: Incorporating molecular detail

    NARCIS (Netherlands)

    Postmus, B.R.; Leermakers, F.A.M.; Cohen Stuart, M.A.

    2008-01-01

    We have constructed a model to predict the properties of non-ionic (alkyl-ethylene oxide) (C(n)E(m)) surfactants, both in aqueous solutions and near a silica surface, based upon the self-consistent field theory using the Scheutjens-Fleer discretisation scheme. The system has the pH and the ionic

  11. Estimating carbon and showing impacts of drought using satellite data in regression-tree models

    Science.gov (United States)

    Boyte, Stephen; Wylie, Bruce K.; Howard, Danny; Dahal, Devendra; Gilmanov, Tagir G.

    2018-01-01

    Integrating spatially explicit biogeophysical and remotely sensed data into regression-tree models enables the spatial extrapolation of training data over large geographic spaces, allowing a better understanding of broad-scale ecosystem processes. The current study presents annual gross primary production (GPP) and annual ecosystem respiration (RE) for 2000–2013 in several short-statured vegetation types using carbon flux data from towers that are located strategically across the conterminous United States (CONUS). We calculate carbon fluxes (annual net ecosystem production [NEP]) for each year in our study period, which includes 2012 when drought and higher-than-normal temperatures influence vegetation productivity in large parts of the study area. We present and analyse carbon flux dynamics in the CONUS to better understand how drought affects GPP, RE, and NEP. Model accuracy metrics show strong correlation coefficients (r) (r ≥ 94%) between training and estimated data for both GPP and RE. Overall, average annual GPP, RE, and NEP are relatively constant throughout the study period except during 2012 when almost 60% less carbon is sequestered than normal. These results allow us to conclude that this modelling method effectively estimates carbon dynamics through time and allows the exploration of impacts of meteorological anomalies and vegetation types on carbon dynamics.

  12. Visualizing Three-dimensional Slab Geometries with ShowEarthModel

    Science.gov (United States)

    Chang, B.; Jadamec, M. A.; Fischer, K. M.; Kreylos, O.; Yikilmaz, M. B.

    2017-12-01

    Seismic data that characterize the morphology of modern subducted slabs on Earth suggest that a two-dimensional paradigm is no longer adequate to describe the subduction process. Here we demonstrate the effect of data exploration of three-dimensional (3D) global slab geometries with the open source program ShowEarthModel. ShowEarthModel was designed specifically to support data exploration, by focusing on interactivity and real-time response using the Vrui toolkit. Sixteen movies are presented that explore the 3D complexity of modern subduction zones on Earth. The first movie provides a guided tour through the Earth's major subduction zones, comparing the global slab geometry data sets of Gudmundsson and Sambridge (1998), Syracuse and Abers (2006), and Hayes et al. (2012). Fifteen regional movies explore the individual subduction zones and regions intersecting slabs, using the Hayes et al. (2012) slab geometry models where available and the Engdahl and Villasenor (2002) global earthquake data set. Viewing the subduction zones in this way provides an improved conceptualization of the 3D morphology within a given subduction zone as well as the 3D spatial relations between the intersecting slabs. This approach provides a powerful tool for rendering earth properties and broadening capabilities in both Earth Science research and education by allowing for whole earth visualization. The 3D characterization of global slab geometries is placed in the context of 3D slab-driven mantle flow and observations of shear wave splitting in subduction zones. These visualizations contribute to the paradigm shift from a 2D to 3D subduction framework by facilitating the conceptualization of the modern subduction system on Earth in 3D space.

  13. Using a Theory-Consistent CVAR Scenario to Test an Exchange Rate Model Based on Imperfect Knowledge

    Directory of Open Access Journals (Sweden)

    Katarina Juselius

    2017-07-01

    Full Text Available A theory-consistent CVAR scenario describes a set of testable regularieties one should expect to see in the data if the basic assumptions of the theoretical model are empirically valid. Using this method, the paper demonstrates that all basic assumptions about the shock structure and steady-state behavior of an an imperfect knowledge based model for exchange rate determination can be formulated as testable hypotheses on common stochastic trends and cointegration. This model obtaines remarkable support for almost every testable hypothesis and is able to adequately account for the long persistent swings in the real exchange rate.

  14. Etoposide incorporated into camel milk phospholipids liposomes shows increased activity against fibrosarcoma in a mouse model.

    Science.gov (United States)

    Maswadeh, Hamzah M; Aljarbou, Ahmad N; Alorainy, Mohammed S; Alsharidah, Mansour S; Khan, Masood A

    2015-01-01

    Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS). Anticancer drug etoposide (ETP) was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP) and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes) and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes). The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

  15. Etoposide Incorporated into Camel Milk Phospholipids Liposomes Shows Increased Activity against Fibrosarcoma in a Mouse Model

    Directory of Open Access Journals (Sweden)

    Hamzah M. Maswadeh

    2015-01-01

    Full Text Available Phospholipids were isolated from camel milk and identified by using high performance liquid chromatography and gas chromatography-mass spectrometry (GC/MS. Anticancer drug etoposide (ETP was entrapped in liposomes, prepared from camel milk phospholipids, to determine its activity against fibrosarcoma in a murine model. Fibrosarcoma was induced in mice by injecting benzopyrene (BAP and tumor-bearing mice were treated with various formulations of etoposide, including etoposide entrapped camel milk phospholipids liposomes (ETP-Cam-liposomes and etoposide-loaded DPPC-liposomes (ETP-DPPC-liposomes. The tumor-bearing mice treated with ETP-Cam-liposomes showed slow progression of tumors and increased survival compared to free ETP or ETP-DPPC-liposomes. These results suggest that ETP-Cam-liposomes may prove to be a better drug delivery system for anticancer drugs.

  16. Phenolic Acids from Wheat Show Different Absorption Profiles in Plasma: A Model Experiment with Catheterized Pigs

    DEFF Research Database (Denmark)

    Nørskov, Natalja; Hedemann, Mette Skou; Theil, Peter Kappel

    2013-01-01

    consumed. Benzoic acid derivatives showed low concentration in the plasma (diets. The exception was p-hydroxybenzoic acid, with a plasma concentration (4 ± 0.4 μM), much higher than the other plant phenolic acids, likely because it is an intermediate in the phenolic acid metabolism......The concentration and absorption of the nine phenolic acids of wheat were measured in a model experiment with catheterized pigs fed whole grain wheat and wheat aleurone diets. Six pigs in a repeated crossover design were fitted with catheters in the portal vein and mesenteric artery to study....... It was concluded that plant phenolic acids undergo extensive interconversion in the colon and that their absorption profiles reflected their low bioavailability in the plant matrix....

  17. Ebola Virus Makona Shows Reduced Lethality in an Immune-deficient Mouse Model.

    Science.gov (United States)

    Smither, Sophie J; Eastaugh, Lin; Ngugi, Sarah; O'Brien, Lyn; Phelps, Amanda; Steward, Jackie; Lever, Mark Stephen

    2016-10-15

    Ebola virus Makona (EBOV-Makona; from the 2013-2016 West Africa outbreak) shows decreased virulence in an immune-deficient mouse model, compared with a strain from 1976. Unlike other filoviruses tested, EBOV-Makona may be slightly more virulent by the aerosol route than by the injected route, as 2 mice died following aerosol exposure, compared with no mortality among mice that received intraperitoneal injection of equivalent or higher doses. Although most mice did not succumb to infection, the detection of an immunoglobulin G antibody response along with observed clinical signs suggest that the mice were infected but able to clear the infection and recover. We hypothesize that this may be due to the growth rates and kinetics of the virus, which appear slower than that for other filoviruses and consequently give more time for an immune response that results in clearance of the virus. In this instance, the immune-deficient mouse model is unlikely to be appropriate for testing medical countermeasures against this EBOV-Makona stock but may provide insight into pathogenesis and the immune response to virus. © Crown copyright 2016.

  18. Branch-based model for the diameters of the pulmonary airways: accounting for departures from self-consistency and registration errors.

    Science.gov (United States)

    Neradilek, Moni B; Polissar, Nayak L; Einstein, Daniel R; Glenny, Robb W; Minard, Kevin R; Carson, James P; Jiao, Xiangmin; Jacob, Richard E; Cox, Timothy C; Postlethwait, Edward M; Corley, Richard A

    2012-06-01

    We examine a previously published branch-based approach for modeling airway diameters that is predicated on the assumption of self-consistency across all levels of the tree. We mathematically formulate this assumption, propose a method to test it and develop a more general model to be used when the assumption is violated. We discuss the effect of measurement error on the estimated models and propose methods that take account of error. The methods are illustrated on data from MRI and CT images of silicone casts of two rats, two normal monkeys, and one ozone-exposed monkey. Our results showed substantial departures from self-consistency in all five subjects. When departures from self-consistency exist, we do not recommend using the self-consistency model, even as an approximation, as we have shown that it may likely lead to an incorrect representation of the diameter geometry. The new variance model can be used instead. Measurement error has an important impact on the estimated morphometry models and needs to be addressed in the analysis. Copyright © 2012 Wiley Periodicals, Inc.

  19. Towards a Self-Consistent Physical Framework for Modeling Coupled Human and Physical Activities during the Anthropocene

    Science.gov (United States)

    Garrett, T. J.

    2014-12-01

    Studies of the response of global climate to anthropogenic activities rely upon scenarios for future human activity to provide a range of possible trajectories for greenhouse gases emissions over the coming century. Sophisticated integrated models are used to explore not only what will happen, but what should happen in order to optimize societal well-being. Hundreds of equations might be used to account for the interplay between human decisions, technological change, and macroeconomic priniciples. In contrast, the model equations used to describe geophysical phenomena look very different because they are a) purely deterministic and b) consistent with basic thermodynamic laws. This inconsistency between macroeconomics and physics suggests a rather unhappy marriage. During the Anthropocene the evolution of humanity and our environment will become increasingly intertwined. Representing such a coupling suggests a need for a common theoretical basis. To this end, the approach that is described here is to treat civilization like any other physical process, that is as an open, non-equilibrium thermodynamic system that dissipates energy and diffuses matter in order to sustain existing circulations and to further its material growth. Theoretical arguments and over 40 years of measurements show that a very general representation of global economic wealth (not GDP) has been tied to rates of global primary energy consumption through a constant 7.1 ± 0.1 mW per year 2005 USD. This link between physics and economics leads to very simple expressions for how fast civilization and its rate of energy consumption grow. These are expressible as a function of rates of energy and material resource discovery and depletion, and of the magnitude of externally imposed decay. The equations are validated through hindcasts that show, for example, that economic conditions in the 1950s can be invoked to make remarkably accurate forecasts of present rates of global GDP growth and primary energy

  20. Shingle 2.0: generalising self-consistent and automated domain discretisation for multi-scale geophysical models

    Directory of Open Access Journals (Sweden)

    A. S. Candy

    2018-01-01

    Full Text Available The approaches taken to describe and develop spatial discretisations of the domains required for geophysical simulation models are commonly ad hoc, model- or application-specific, and under-documented. This is particularly acute for simulation models that are flexible in their use of multi-scale, anisotropic, fully unstructured meshes where a relatively large number of heterogeneous parameters are required to constrain their full description. As a consequence, it can be difficult to reproduce simulations, to ensure a provenance in model data handling and initialisation, and a challenge to conduct model intercomparisons rigorously. This paper takes a novel approach to spatial discretisation, considering it much like a numerical simulation model problem of its own. It introduces a generalised, extensible, self-documenting approach to carefully describe, and necessarily fully, the constraints over the heterogeneous parameter space that determine how a domain is spatially discretised. This additionally provides a method to accurately record these constraints, using high-level natural language based abstractions that enable full accounts of provenance, sharing, and distribution. Together with this description, a generalised consistent approach to unstructured mesh generation for geophysical models is developed that is automated, robust and repeatable, quick-to-draft, rigorously verified, and consistent with the source data throughout. This interprets the description above to execute a self-consistent spatial discretisation process, which is automatically validated to expected discrete characteristics and metrics. Library code, verification tests, and examples available in the repository at https://github.com/shingleproject/Shingle. Further details of the project presented at http://shingleproject.org.

  1. Shingle 2.0: generalising self-consistent and automated domain discretisation for multi-scale geophysical models

    Science.gov (United States)

    Candy, Adam S.; Pietrzak, Julie D.

    2018-01-01

    The approaches taken to describe and develop spatial discretisations of the domains required for geophysical simulation models are commonly ad hoc, model- or application-specific, and under-documented. This is particularly acute for simulation models that are flexible in their use of multi-scale, anisotropic, fully unstructured meshes where a relatively large number of heterogeneous parameters are required to constrain their full description. As a consequence, it can be difficult to reproduce simulations, to ensure a provenance in model data handling and initialisation, and a challenge to conduct model intercomparisons rigorously. This paper takes a novel approach to spatial discretisation, considering it much like a numerical simulation model problem of its own. It introduces a generalised, extensible, self-documenting approach to carefully describe, and necessarily fully, the constraints over the heterogeneous parameter space that determine how a domain is spatially discretised. This additionally provides a method to accurately record these constraints, using high-level natural language based abstractions that enable full accounts of provenance, sharing, and distribution. Together with this description, a generalised consistent approach to unstructured mesh generation for geophysical models is developed that is automated, robust and repeatable, quick-to-draft, rigorously verified, and consistent with the source data throughout. This interprets the description above to execute a self-consistent spatial discretisation process, which is automatically validated to expected discrete characteristics and metrics. Library code, verification tests, and examples available in the repository at https://github.com/shingleproject/Shingle. Further details of the project presented at http://shingleproject.org.

  2. Multi-Time Scale Model Order Reduction and Stability Consistency Certification of Inverter-Interfaced DG System in AC Microgrid

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Meng

    2018-01-01

    Full Text Available AC microgrid mainly comprise inverter-interfaced distributed generators (IIDGs, which are nonlinear complex systems with multiple time scales, including frequency control, time delay measurements, and electromagnetic transients. The droop control-based IIDG in an AC microgrid is selected as the research object in this study, which comprises power droop controller, voltage- and current-loop controllers, and filter and line. The multi-time scale characteristics of the detailed IIDG model are divided based on singular perturbation theory. In addition, the IIDG model order is reduced by neglecting the system fast dynamics. The static and transient stability consistency of the IIDG model order reduction are demonstrated by extracting features of the IIDG small signal model and using the quadratic approximation method of the stability region boundary, respectively. The dynamic response consistencies of the IIDG model order reduction are evaluated using the frequency, damping and amplitude features extracted by the Prony transformation. Results are applicable to provide a simplified model for the dynamic characteristic analysis of IIDG systems in AC microgrid. The accuracy of the proposed method is verified by using the eigenvalue comparison, the transient stability index comparison and the dynamic time-domain simulation.

  3. A relativistic self-consistent model for studying enhancement of space charge limited emission due to counter-streaming ions

    Science.gov (United States)

    Lin, M. C.; Verboncoeur, J.

    2016-10-01

    A maximum electron current transmitted through a planar diode gap is limited by space charge of electrons dwelling across the gap region, the so called space charge limited (SCL) emission. By introducing a counter-streaming ion flow to neutralize the electron charge density, the SCL emission can be dramatically raised, so electron current transmission gets enhanced. In this work, we have developed a relativistic self-consistent model for studying the enhancement of maximum transmission by a counter-streaming ion current. The maximum enhancement is found when the ion effect is saturated, as shown analytically. The solutions in non-relativistic, intermediate, and ultra-relativistic regimes are obtained and verified with 1-D particle-in-cell simulations. This self-consistent model is general and can also serve as a comparison for verification of simulation codes, as well as extension to higher dimensions.

  4. Using Trait-State Models to Evaluate the Longitudinal Consistency of Global Self-Esteem From Adolescence to Adulthood

    OpenAIRE

    Donnellan, M. Brent; Kenny, David A.; Trzesniewski, Kali H.; Lucas, Richard E.; Conger, Rand D.

    2012-01-01

    The present research used a latent variable trait-state model to evaluate the longitudinal consistency of self-esteem during the transition from adolescence to adulthood. Analyses were based on ten administrations of the Rosenberg Self-Esteem scale (Rosenberg, 1965) spanning the ages of approximately 13 to 32 for a sample of 451 participants. Results indicated that a completely stable trait factor and an autoregressive trait factor accounted for the majority of the variance in latent self-est...

  5. Determinants of consistent condom use among college students in China: application of the information-motivation-behavior skills (IMB) model.

    Science.gov (United States)

    Liu, Zhihao; Wei, Pingmin; Huang, Minghao; Liu, Yuan bao; Li, Lucy; Gong, Xiao; Chen, Juan; Li, Xiaoning

    2014-01-01

    Due to the increase incidents of premarital sex and the lack of reproductive health services, college students are at high risk of HIV/AIDS infections in China. This study was designed to examine the predictors of consistency of condom use among college students based on the Information-Motivation-Behavioral Skills (IMB) model and to describe the relationships between the model constructs. A cross-sectional study was conducted to assess HIV/AIDS related information, motivation, behavioral skills and preventive behavior among college students in five colleges and universities in Nanjing, China. An anonymous questionnaire survey was conducted for data collection, and the structural equation model (SEM) was used to assess the IMB model. A total of 3183 participants completed this study. The average age was 19.90 years (SD = 1.43, range 16 to 25). 342 (10.7%) participants of them reported having had premarital sex, among whom 30.7% reported having had a consistent condom use, 13.7% with the experience of abortion (including the participants whose sex partner has the same experience), 32.7% of participants had experience of multiple sex partners. The final IMB model provided acceptable fit to the data (CFI = 0.992, RMSEA = 0.028). Preventive behavior was significantly predicted by behavioral skills (β = 0.754, Pmotivation (β = 0.363, Pstudents in China. The main influencing factor of preventive behavior among college students is behavioral skills. Both information and motivation could affect preventive behavior through behavioral skills. Further research could develop preventive interventions based on the IMB model to promote consistent condom use among college students in China.

  6. Comparison of bootstrap current and plasma conductivity models applied in a self-consistent equilibrium calculation for Tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Maria Celia Ramos; Ludwig, Gerson Otto [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. Associado de Plasma]. E-mail: mcr@plasma.inpe.br

    2004-07-01

    Different bootstrap current formulations are implemented in a self-consistent equilibrium calculation obtained from a direct variational technique in fixed boundary tokamak plasmas. The total plasma current profile is supposed to have contributions of the diamagnetic, Pfirsch-Schlueter, and the neoclassical Ohmic and bootstrap currents. The Ohmic component is calculated in terms of the neoclassical conductivity, compared here among different expressions, and the loop voltage determined consistently in order to give the prescribed value of the total plasma current. A comparison among several bootstrap current models for different viscosity coefficient calculations and distinct forms for the Coulomb collision operator is performed for a variety of plasma parameters of the small aspect ratio tokamak ETE (Experimento Tokamak Esferico) at the Associated Plasma Laboratory of INPE, in Brazil. We have performed this comparison for the ETE tokamak so that the differences among all the models reported here, mainly regarding plasma collisionality, can be better illustrated. The dependence of the bootstrap current ratio upon some plasma parameters in the frame of the self-consistent calculation is also analysed. We emphasize in this paper what we call the Hirshman-Sigmar/Shaing model, valid for all collisionality regimes and aspect ratios, and a fitted formulation proposed by Sauter, which has the same range of validity but is faster to compute than the previous one. The advantages or possible limitations of all these different formulations for the bootstrap current estimate are analysed throughout this work. (author)

  7. Atovaquone Nanosuspensions Show Excellent Therapeutic Effect in a New Murine Model of Reactivated Toxoplasmosis

    Science.gov (United States)

    Schöler, Nadja; Krause, Karsten; Kayser, Oliver; Müller, Rainer H.; Borner, Klaus; Hahn, Helmut; Liesenfeld, Oliver

    2001-01-01

    Immunocompromised patients are at risk of developing toxoplasma encephalitis (TE). Standard therapy regimens (including sulfadiazine plus pyrimethamine) are hampered by severe side effects. While atovaquone has potent in vitro activity against Toxoplasma gondii, it is poorly absorbed after oral administration and shows poor therapeutic efficacy against TE. To overcome the low absorption of atovaquone, we prepared atovaquone nanosuspensions (ANSs) for intravenous (i.v.) administration. At concentrations higher than 1.0 μg/ml, ANS did not exert cytotoxicity and was as effective as free atovaquone (i.e., atovaquone suspended in medium) against T. gondii in freshly isolated peritoneal macrophages. In a new murine model of TE that closely mimics reactivated toxoplasmosis in immunocompromised hosts, using mice with a targeted mutation in the gene encoding the interferon consensus sequence binding protein, i.v.-administered ANS doses of 10.0 mg/kg of body weight protected the animals against development of TE and death. Atovaquone was detectable in the sera, brains, livers, and lungs of mice by high-performance liquid chromatography. Development of TE and mortality in mice treated with 1.0- or 0.1-mg/kg i.v. doses of ANS did not differ from that in mice treated orally with 100 mg of atovaquone/kg. In conclusion, i.v. ANSs may prove to be an effective treatment alternative for patients with TE. PMID:11353624

  8. New azole derivatives showing antimicrobial effects and their mechanism of antifungal activity by molecular modeling studies.

    Science.gov (United States)

    Doğan, İnci Selin; Saraç, Selma; Sari, Suat; Kart, Didem; Eşsiz Gökhan, Şebnem; Vural, İmran; Dalkara, Sevim

    2017-04-21

    Azole antifungals are potent inhibitors of fungal lanosterol 14α demethylase (CYP51) and have been used for eradication of systemic candidiasis clinically. Herein we report the design, synthesis, and biological evaluation of a series of 1-phenyl/1-(4-chlorophenyl)-2-(1H-imidazol-1-yl)ethanol esters. Many of these derivatives showed fungal growth inhibition at very low concentrations. Minimal inhibition concentration (MIC) value of 15 was 0.125 μg/mL against Candida albicans. Additionally, some of our compounds, such as 19 (MIC: 0.25 μg/mL), were potent against resistant C. glabrata, a fungal strain less susceptible to some first-line antifungal drugs. We confirmed their antifungal efficacy by antibiofilm test and their safety against human monocytes by cytotoxicity assay. To rationalize their mechanism of action, we performed computational analysis utilizing molecular docking and dynamics simulations on the C. albicans and C. glabrata CYP51 (CACYP51 and CGCYP51) homology models we built. Leu130 and T131 emerged as possible key residues for inhibition of CGCYP51 by 19. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  9. A stock-flow consistent input-output model with applications to energy price shocks, interest rates, and heat emissions

    Science.gov (United States)

    Berg, Matthew; Hartley, Brian; Richters, Oliver

    2015-01-01

    By synthesizing stock-flow consistent models, input-output models, and aspects of ecological macroeconomics, a method is developed to simultaneously model monetary flows through the financial system, flows of produced goods and services through the real economy, and flows of physical materials through the natural environment. This paper highlights the linkages between the physical environment and the economic system by emphasizing the role of the energy industry. A conceptual model is developed in general form with an arbitrary number of sectors, while emphasizing connections with the agent-based, econophysics, and complexity economics literature. First, we use the model to challenge claims that 0% interest rates are a necessary condition for a stationary economy and conduct a stability analysis within the parameter space of interest rates and consumption parameters of an economy in stock-flow equilibrium. Second, we analyze the role of energy price shocks in contributing to recessions, incorporating several propagation and amplification mechanisms. Third, implied heat emissions from energy conversion and the effect of anthropogenic heat flux on climate change are considered in light of a minimal single-layer atmosphere climate model, although the model is only implicitly, not explicitly, linked to the economic model.

  10. Determinants of consistent condom use among college students in China: application of the information-motivation-behavior skills (IMB model.

    Directory of Open Access Journals (Sweden)

    Zhihao Liu

    Full Text Available BACKGROUND: Due to the increase incidents of premarital sex and the lack of reproductive health services, college students are at high risk of HIV/AIDS infections in China. This study was designed to examine the predictors of consistency of condom use among college students based on the Information-Motivation-Behavioral Skills (IMB model and to describe the relationships between the model constructs. METHODS: A cross-sectional study was conducted to assess HIV/AIDS related information, motivation, behavioral skills and preventive behavior among college students in five colleges and universities in Nanjing, China. An anonymous questionnaire survey was conducted for data collection, and the structural equation model (SEM was used to assess the IMB model. RESULTS: A total of 3183 participants completed this study. The average age was 19.90 years (SD = 1.43, range 16 to 25. 342 (10.7% participants of them reported having had premarital sex, among whom 30.7% reported having had a consistent condom use, 13.7% with the experience of abortion (including the participants whose sex partner has the same experience, 32.7% of participants had experience of multiple sex partners. The final IMB model provided acceptable fit to the data (CFI = 0.992, RMSEA = 0.028. Preventive behavior was significantly predicted by behavioral skills (β = 0.754, P<0.001. Information (β = 0.138, P<0.001 and motivation (β = 0.363, P<0.001 were indirectly affected preventive behavior, and was mediated through behavioral skills. CONCLUSIONS: The results of the study demonstrate the utility of the IMB model for consistent condom use among college students in China. The main influencing factor of preventive behavior among college students is behavioral skills. Both information and motivation could affect preventive behavior through behavioral skills. Further research could develop preventive interventions based on the IMB model to promote consistent condom

  11. Showing a model's eye movements in examples does not improve learning of problem-solving tasks

    NARCIS (Netherlands)

    van Marlen, Tim; van Wermeskerken, Margot; Jarodzka, Halszka; van Gog, Tamara

    2016-01-01

    Eye movement modeling examples (EMME) are demonstrations of a computer-based task by a human model (e.g., a teacher), with the model's eye movements superimposed on the task to guide learners' attention. EMME have been shown to enhance learning of perceptual classification tasks; however, it is an

  12. Self-consistent Non-LTE Model of Infrared Molecular Emissions and Oxygen Dayglows in the Mesosphere and Lower Thermosphere

    Science.gov (United States)

    Feofilov, Artem G.; Yankovsky, Valentine A.; Pesnell, William D.; Kutepov, Alexander A.; Goldberg, Richard A.; Mauilova, Rada O.

    2007-01-01

    We present the new version of the ALI-ARMS (for Accelerated Lambda Iterations for Atmospheric Radiation and Molecular Spectra) model. The model allows simultaneous self-consistent calculating the non-LTE populations of the electronic-vibrational levels of the O3 and O2 photolysis products and vibrational level populations of CO2, N2,O2, O3, H2O, CO and other molecules with detailed accounting for the variety of the electronic-vibrational, vibrational-vibrational and vibrational-translational energy exchange processes. The model was used as the reference one for modeling the O2 dayglows and infrared molecular emissions for self-consistent diagnostics of the multi-channel space observations of MLT in the SABER experiment It also allows reevaluating the thermalization efficiency of the absorbed solar ultraviolet energy and infrared radiative cooling/heating of MLT by detailed accounting of the electronic-vibrational relaxation of excited photolysis products via the complex chain of collisional energy conversion processes down to the vibrational energy of optically active trace gas molecules.

  13. A consistent framework for modeling inorganic pesticides: Adaptation of life cycle inventory models to metal-base pesticides

    DEFF Research Database (Denmark)

    Peña, N.A.; Anton, A.; Fantke, Peter

    2016-01-01

    Quantifying over the life cycle of a product or service the chemical emissions to the environment in the life cycle inventory (LCI) phase is typically based on generic assumptions. Regarding the LCI application to agricultural systems the estimation of pesticide emissions is often based on standard......, and it will influence the outcomes of the impact profile. The pesticide emission model PestLCI 2.0 is the most advanced currently available inventory model for LCA intended to provide an estimation of organic pesticide emission fractions to the environment. We use this model as starting point for quantifying emission...... estimate metal-specific pesticide emission fractions, addressing the issue of inorganic pesticides for inventory analysis in LCA of agricultural systems....

  14. Multi-model comparison highlights consistency in predicted effect of warming on a semi-arid shrub

    Science.gov (United States)

    Renwick, Katherine M.; Curtis, Caroline; Kleinhesselink, Andrew R.; Schlaepfer, Daniel R.; Bradley, Bethany A.; Aldridge, Cameron L.; Poulter, Benjamin; Adler, Peter B.

    2018-01-01

    A number of modeling approaches have been developed to predict the impacts of climate change on species distributions, performance, and abundance. The stronger the agreement from models that represent different processes and are based on distinct and independent sources of information, the greater the confidence we can have in their predictions. Evaluating the level of confidence is particularly important when predictions are used to guide conservation or restoration decisions. We used a multi-model approach to predict climate change impacts on big sagebrush (Artemisia tridentata), the dominant plant species on roughly 43 million hectares in the western United States and a key resource for many endemic wildlife species. To evaluate the climate sensitivity of A. tridentata, we developed four predictive models, two based on empirically derived spatial and temporal relationships, and two that applied mechanistic approaches to simulate sagebrush recruitment and growth. This approach enabled us to produce an aggregate index of climate change vulnerability and uncertainty based on the level of agreement between models. Despite large differences in model structure, predictions of sagebrush response to climate change were largely consistent. Performance, as measured by change in cover, growth, or recruitment, was predicted to decrease at the warmest sites, but increase throughout the cooler portions of sagebrush's range. A sensitivity analysis indicated that sagebrush performance responds more strongly to changes in temperature than precipitation. Most of the uncertainty in model predictions reflected variation among the ecological models, raising questions about the reliability of forecasts based on a single modeling approach. Our results highlight the value of a multi-model approach in forecasting climate change impacts and uncertainties and should help land managers to maximize the value of conservation investments.

  15. Predicting knee replacement damage in a simulator machine using a computational model with a consistent wear factor.

    Science.gov (United States)

    Zhao, Dong; Sakoda, Hideyuki; Sawyer, W Gregory; Banks, Scott A; Fregly, Benjamin J

    2008-02-01

    Wear of ultrahigh molecular weight polyethylene remains a primary factor limiting the longevity of total knee replacements (TKRs). However, wear testing on a simulator machine is time consuming and expensive, making it impractical for iterative design purposes. The objectives of this paper were first, to evaluate whether a computational model using a wear factor consistent with the TKR material pair can predict accurate TKR damage measured in a simulator machine, and second, to investigate how choice of surface evolution method (fixed or variable step) and material model (linear or nonlinear) affect the prediction. An iterative computational damage model was constructed for a commercial knee implant in an AMTI simulator machine. The damage model combined a dynamic contact model with a surface evolution model to predict how wear plus creep progressively alter tibial insert geometry over multiple simulations. The computational framework was validated by predicting wear in a cylinder-on-plate system for which an analytical solution was derived. The implant damage model was evaluated for 5 million cycles of simulated gait using damage measurements made on the same implant in an AMTI machine. Using a pin-on-plate wear factor for the same material pair as the implant, the model predicted tibial insert wear volume to within 2% error and damage depths and areas to within 18% and 10% error, respectively. Choice of material model had little influence, while inclusion of surface evolution affected damage depth and area but not wear volume predictions. Surface evolution method was important only during the initial cycles, where variable step was needed to capture rapid geometry changes due to the creep. Overall, our results indicate that accurate TKR damage predictions can be made with a computational model using a constant wear factor obtained from pin-on-plate tests for the same material pair, and furthermore, that surface evolution method matters only during the initial

  16. Thermodynamically consistent modeling and simulation of multi-component two-phase flow model with partial miscibility

    KAUST Repository

    Kou, Jisheng

    2016-11-25

    A general diffuse interface model with a realistic equation of state (e.g. Peng-Robinson equation of state) is proposed to describe the multi-component two-phase fluid flow based on the principles of the NVT-based framework which is a latest alternative over the NPT-based framework to model the realistic fluids. The proposed model uses the Helmholtz free energy rather than Gibbs free energy in the NPT-based framework. Different from the classical routines, we combine the first law of thermodynamics and related thermodynamical relations to derive the entropy balance equation, and then we derive a transport equation of the Helmholtz free energy density. Furthermore, by using the second law of thermodynamics, we derive a set of unified equations for both interfaces and bulk phases that can describe the partial miscibility of two fluids. A relation between the pressure gradient and chemical potential gradients is established, and this relation leads to a new formulation of the momentum balance equation, which demonstrates that chemical potential gradients become the primary driving force of fluid motion. Moreover, we prove that the proposed model satisfies the total (free) energy dissipation with time. For numerical simulation of the proposed model, the key difficulties result from the strong nonlinearity of Helmholtz free energy density and tight coupling relations between molar densities and velocity. To resolve these problems, we propose a novel convex-concave splitting of Helmholtz free energy density and deal well with the coupling relations between molar densities and velocity through very careful physical observations with a mathematical rigor. We prove that the proposed numerical scheme can preserve the discrete (free) energy dissipation. Numerical tests are carried out to verify the effectiveness of the proposed method.

  17. Using Trait-State Models to Evaluate the Longitudinal Consistency of Global Self-Esteem From Adolescence to Adulthood

    Science.gov (United States)

    Donnellan, M. Brent; Kenny, David A.; Trzesniewski, Kali H.; Lucas, Richard E.; Conger, Rand D.

    2012-01-01

    The present research used a latent variable trait-state model to evaluate the longitudinal consistency of self-esteem during the transition from adolescence to adulthood. Analyses were based on ten administrations of the Rosenberg Self-Esteem scale (Rosenberg, 1965) spanning the ages of approximately 13 to 32 for a sample of 451 participants. Results indicated that a completely stable trait factor and an autoregressive trait factor accounted for the majority of the variance in latent self-esteem assessments, whereas state factors accounted for about 16% of the variance in repeated assessments of latent self-esteem. The stability of individual differences in self-esteem increased with age consistent with the cumulative continuity principle of personality development. PMID:23180899

  18. Development of a simple force prediction model and consistency assessment of knee movements in ten-pin bowling

    Directory of Open Access Journals (Sweden)

    Li-Cheng Hsieh

    2012-08-01

    Full Text Available The aim of this research is to use LabVIEW to help bowlers understand theirjoint movements, forces acting on their joints, and the consistency of their knee movements while competing in ten-pin bowling. Kinetic and kinematic data relating to the lower limbs were derived from bowlers’ joint angles and the joint forces were calculated from the Euler angles using the inverse dynamics method with Newton-Euler equations. An artificial-neural-network (ANN-based data-driven model for predicting knee forces using the Euler angles was developed. This approach allows for the collection of data inbowling alleys without the use of force plates. Correlation coefficients were computed after ANN training and all values exceeded 0.9. This result implies a strong correlation between the joint angles and forces. Furthermore, the predicted 3D forces (obtained from ANN simulations and the measured forces (obtained from force plates via the inverse dynamics method are strongly correlated. The agreement between the predicted andmeasured forces was evaluated by the coefficient of determination (R2, which reflects the bowler’s consistency and steadiness of the bowling motion at the knee. The R2 value was beneficial in assessing the consistency of the bowling motion. An R2 value close to 1 implies a more consistent sliding motion. This research enables the prediction of the forceson the knee during ten-pin bowling by ANN simulations using the measured knee angles. Consequently, coaches and bowlers can use the developed ANN model and the analysis module to improve bowling motion.

  19. Classifying multi-model wheat yield impact response surfaces showing sensitivity to temperature and precipitation change

    NARCIS (Netherlands)

    Fronzek, Stefan; Pirttioja, Nina; Carter, Timothy R.; Bindi, Marco; Hoffmann, Holger; Palosuo, Taru; Ruiz-Ramos, Margarita; Tao, Fulu; Trnka, Miroslav; Acutis, Marco; Asseng, Senthold; Baranowski, Piotr; Basso, Bruno; Bodin, Per; Buis, Samuel; Cammarano, Davide; Deligios, Paola; Destain, Marie France; Dumont, Benjamin; Ewert, Frank; Ferrise, Roberto; François, Louis; Gaiser, Thomas; Hlavinka, Petr; Jacquemin, Ingrid; Kersebaum, Kurt Christian; Kollas, Chris; Krzyszczak, Jaromir; Lorite, Ignacio J.; Minet, Julien; Minguez, M.I.; Montesino, Manuel; Moriondo, Marco; Müller, Christoph; Nendel, Claas; Öztürk, Isik; Perego, Alessia; Rodríguez, Alfredo; Ruane, Alex C.; Ruget, Françoise; Sanna, Mattia; Semenov, Mikhail A.; Slawinski, Cezary; Stratonovitch, Pierre; Supit, Iwan; Waha, Katharina; Wang, Enli; Wu, Lianhai; Zhao, Zhigan; Rötter, Reimund P.

    2018-01-01

    Crop growth simulation models can differ greatly in their treatment of key processes and hence in their response to environmental conditions. Here, we used an ensemble of 26 process-based wheat models applied at sites across a European transect to compare their sensitivity to changes in

  20. Classifying multi-model wheat yield impact response surfaces showing sensitivity to temperature and precipitation change

    Czech Academy of Sciences Publication Activity Database

    Fronzek, S.; Pirttioja, N. K.; Carter, T. R.; Bindi, M.; Hoffmann, H.; Palosuo, T.; Ruiz-Ramos, M.; Tao, F.; Trnka, Miroslav; Acutis, M.; Asseng, S.; Baranowski, P.; Basso, B.; Bodin, P.; Buis, S.; Cammarano, D.; Deligios, P.; Destain, M. F.; Dumont, B.; Ewert, F.; Ferrise, R.; Francois, L.; Gaiser, T.; Hlavinka, Petr; Jacquemin, I.; Kersebaum, K. C.; Kollas, C.; Krzyszczak, J.; Lorite, I. J.; Minet, J.; Ines Minguez, M.; Montesino, M.; Moriondo, M.; Mueller, C.; Nendel, C.; Öztürk, I.; Perego, A.; Rodriguez, A.; Ruane, A. C.; Ruget, F.; Sanna, M.; Semenov, M. A.; Slawinski, C.; Stratonovitch, P.; Supit, I.; Waha, K.; Wang, E.; Wu, L.; Zhao, Z.; Rötter, R.

    2018-01-01

    Roč. 159, jan (2018), s. 209-224 ISSN 0308-521X Keywords : climate-change * crop models * probabilistic assessment * simulating impacts * british catchments * uncertainty * europe * productivity * calibration * adaptation * Classification * Climate change * Crop model * Ensemble * Sensitivity analysis * Wheat Impact factor: 2.571, year: 2016

  1. Predictive Modeling of Influenza Shows the Promise of Applied Evolutionary Biology.

    Science.gov (United States)

    Morris, Dylan H; Gostic, Katelyn M; Pompei, Simone; Bedford, Trevor; Łuksza, Marta; Neher, Richard A; Grenfell, Bryan T; Lässig, Michael; McCauley, John W

    2018-02-01

    Seasonal influenza is controlled through vaccination campaigns. Evolution of influenza virus antigens means that vaccines must be updated to match novel strains, and vaccine effectiveness depends on the ability of scientists to predict nearly a year in advance which influenza variants will dominate in upcoming seasons. In this review, we highlight a promising new surveillance tool: predictive models. Based on data-sharing and close collaboration between the World Health Organization and academic scientists, these models use surveillance data to make quantitative predictions regarding influenza evolution. Predictive models demonstrate the potential of applied evolutionary biology to improve public health and disease control. We review the state of influenza predictive modeling and discuss next steps and recommendations to ensure that these models deliver upon their considerable biomedical promise. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Development of a Consistent GIS Based Method for Estimating the Groundwater Runoff Parameter for Regional Scale Precipitation-Runoff Models

    Science.gov (United States)

    Bjerklie, D. M.

    2014-12-01

    As part of a U. S. Geological Survey effort to (1) estimate river discharge in ungaged basins, (2) understand runoff quantity and timing for watersheds between gaging stations, and (3) estimate potential future streamflow, a national scale precipitation runoff model is in development. The effort uses the USGS Precipitation Runoff Modeling System (PRMS) model. The model development strategy includes methods to assign hydrologic routing coefficients a priori from national scale GIS data bases. Once developed, the model can serve as an initial baseline for more detailed and locally/regionally calibrated models designed for specific projects and purposes. One of the key hydrologic routing coefficients is the groundwater coefficient (gw_coef). This study estimates the gw_coef from continental US GIS data, including geology, drainage density, aquifer type, vegetation type, and baseflow index information. The gw_coef is applied in regional PRMS models and is estimated using two methods. The first method uses a statistical model to predict the gw_coef from weighted average values of surficial geologic materials, dominant aquifer type, baseflow index, vegetation type, and the drainage density. The second method computes the gw_coef directly from the physical conditions in the watershed including the percentage geologic material and the drainage density. The two methods are compared against the gw_coef derived from streamflow records, and tested for selected rivers in different regions of the country. To address the often weak correlation between geology and baseflow, the existence of groundwater sinks, and complexities of groundwater flow paths, the spatial characteristics of the gw_coef prediction error were evaluated, and a correction factor developed from the spatial error distribution. This provides a consistent and improved method to estimate the gw_coef for regional PRMS models that is derived from available GIS data and physical information for watersheds.

  3. Physical Properties of the SKYLAB North Polar Coronal Hole with an Extended Base and its MHD Self-Consistent Modelling

    Science.gov (United States)

    Bravo, S.; Ocania, G.

    1991-04-01

    energetization of the wind, one of the possibilities allowed for fltix the observational uncertailities shows a very good agreement wi4 an NI Ill) seli'consistent modelling with the only additional term of the Lorentz force in the iiii equation. Key words: SUN-CORONA

  4. Metabolic modeling of energy balances in Mycoplasma hyopneumoniae shows that pyruvate addition increases growth rate.

    Science.gov (United States)

    Kamminga, Tjerko; Slagman, Simen-Jan; Bijlsma, Jetta J E; Martins Dos Santos, Vitor A P; Suarez-Diez, Maria; Schaap, Peter J

    2017-10-01

    Mycoplasma hyopneumoniae is cultured on large-scale to produce antigen for inactivated whole-cell vaccines against respiratory disease in pigs. However, the fastidious nutrient requirements of this minimal bacterium and the low growth rate make it challenging to reach sufficient biomass yield for antigen production. In this study, we sequenced the genome of M. hyopneumoniae strain 11 and constructed a high quality constraint-based genome-scale metabolic model of 284 chemical reactions and 298 metabolites. We validated the model with time-series data of duplicate fermentation cultures to aim for an integrated model describing the dynamic profiles measured in fermentations. The model predicted that 84% of cellular energy in a standard M. hyopneumoniae cultivation was used for non-growth associated maintenance and only 16% of cellular energy was used for growth and growth associated maintenance. Following a cycle of model-driven experimentation in dedicated fermentation experiments, we were able to increase the fraction of cellular energy used for growth through pyruvate addition to the medium. This increase in turn led to an increase in growth rate and a 2.3 times increase in the total biomass concentration reached after 3-4 days of fermentation, enhancing the productivity of the overall process. The model presented provides a solid basis to understand and further improve M. hyopneumoniae fermentation processes. Biotechnol. Bioeng. 2017;114: 2339-2347. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  5. Thermodynamic consistency of viscoplastic material models involving external variable rates in the evolution equations for the internal variables

    International Nuclear Information System (INIS)

    Malmberg, T.

    1993-09-01

    The objective of this study is to derive and investigate thermodynamic restrictions for a particular class of internal variable models. Their evolution equations consist of two contributions: the usual irreversible part, depending only on the present state, and a reversible but path dependent part, linear in the rates of the external variables (evolution equations of ''mixed type''). In the first instance the thermodynamic analysis is based on the classical Clausius-Duhem entropy inequality and the Coleman-Noll argument. The analysis is restricted to infinitesimal strains and rotations. The results are specialized and transferred to a general class of elastic-viscoplastic material models. Subsequently, they are applied to several viscoplastic models of ''mixed type'', proposed or discussed in the literature (Robinson et al., Krempl et al., Freed et al.), and it is shown that some of these models are thermodynamically inconsistent. The study is closed with the evaluation of the extended Clausius-Duhem entropy inequality (concept of Mueller) where the entropy flux is governed by an assumed constitutive equation in its own right; also the constraining balance equations are explicitly accounted for by the method of Lagrange multipliers (Liu's approach). This analysis is done for a viscoplastic material model with evolution equations of the ''mixed type''. It is shown that this approach is much more involved than the evaluation of the classical Clausius-Duhem entropy inequality with the Coleman-Noll argument. (orig.) [de

  6. Integration and consistency testing of groundwater flow models with hydro-geochemistry in site investigations in Finland

    International Nuclear Information System (INIS)

    Pitkaenen, P.; Loefman, J.; Korkealaakso, J.; Koskinen, L.; Ruotsalainen, P.; Hautojaervi, A.; Aeikaes, T.

    1999-01-01

    In the assessment of the suitability and safety of a geological repository for radioactive waste the understanding of the fluid flow at a site is essential. In order to build confidence in the assessment of the hydrogeological performance of a site in various conditions, integration of hydrological and hydrogeochemical methods and studies provides the primary method for investigating the evolution that has taken place in the past, and for predicting future conditions at the potential disposal site. A systematic geochemical sampling campaign was started since the beginning of 1990's in the Finnish site investigation programme. This enabled the initiating of integration and evaluation of site scale hydrogeochemical and groundwater flow models. Hydrogeochemical information has been used to screen relevant external processes and variables for definition of the initial and boundary conditions in hydrological simulations. The results obtained from interpretation and modelling hydrogeochemical evolution have been employed in testing the hydrogeochemical consistency of conceptual flow models. Integration and testing of flow models with hydrogeochemical information are considered to improve significantly the hydrogeological understanding of a site and increases confidence in conceptual hydrogeological models. (author)

  7. A Simulation Model for Drift Resistive Ballooning Turbulence Examining the Influence of Self-consistent Zonal Flows

    Science.gov (United States)

    Cohen, Bruce; Umansky, Maxim; Joseph, Ilon

    2015-11-01

    Progress is reported on including self-consistent zonal flows in simulations of drift-resistive ballooning turbulence using the BOUT + + framework. Previous published work addressed the simulation of L-mode edge turbulence in realistic single-null tokamak geometry using the BOUT three-dimensional fluid code that solves Braginskii-based fluid equations. The effects of imposed sheared ExB poloidal rotation were included, with a static radial electric field fitted to experimental data. In new work our goal is to include the self-consistent effects on the radial electric field driven by the microturbulence, which contributes to the sheared ExB poloidal rotation (zonal flow generation). We describe a model for including self-consistent zonal flows and an algorithm for maintaining underlying plasma profiles to enable the simulation of steady-state turbulence. We examine the role of Braginskii viscous forces in providing necessary dissipation when including axisymmetric perturbations. We also report on some of the numerical difficulties associated with including the axisymmetric component of the fluctuating fields. This work was performed under the auspices of the U.S. Department of Energy under contract DE-AC52-07NA27344 at the Lawrence Livermore National Laboratory (LLNL-ABS-674950).

  8. Large Sample Hydrology : Building an international sample of watersheds to improve consistency and robustness of model evaluation

    Science.gov (United States)

    Mathevet, Thibault; Kumar, Rohini; Gupta, Hoshin; Vaze, Jai; Andréassian, Vazken

    2015-04-01

    This poster introduces the aims of the Large Sample Hydrology working group (LSH-WG) of the new IAHS Panta Rhei decade (2013-2022). The aim of the LSH-WG is to promote large sample hydrology, as discussed by Gupta et al. (2014) and to invite the community to collaborate on building and sharing a comprehensive and representative world-wide sample of watershed datasets. By doing so, LSH will allow the community to work towards 'hydrological consistency' (Martinez and Gupta, 2011) as a basis for hydrologic model development and evaluation, thereby increasing robustness of the model evaluation process. Classical model evaluation metrics based on 'robust statistics' are needed, but clearly not sufficient: multi-criteria assessments based on multiple hydrological signatures can help to better characterize hydrological functioning. Further, large-sample data sets can greatly facilitate: (i) improved understanding through rigorous testing and comparison of competing model hypothesis and structures, (ii) improved robustness of generalizations through statistical analyses that minimize the influence of outliers and case-specific studies, (iii) classification, regionalization and model transfer across a broad diversity of hydrometeorological contexts, and (iv) estimation of predictive uncertainties at a location and across locations (Mathevet et al., 2006; Andréassian et al., 2009; Gupta et al., 2014) References Andréassian, V., Perrin, C., Berthet, L., Le Moine, N., Lerat, J., Loumagne, C., Oudin, L., Mathevet, T., Ramos, M. H., and Valéry, A.: Crash tests for a standardized evaluation of hydrological models, Hydrology and Earth System Sciences, 1757-1764, 2009. Gupta, H. V., Perrin, C., Blöschl, G., Montanari, A., Kumar, R., Clark, M., and Andréassian, V.: Large-sample hydrology: a need to balance depth with breadth, Hydrol. Earth Syst. Sci., 18, 463-477, doi:10.5194/hess-18-463-2014, 2014. Martinez, G. F., and H. V.Gupta (2011), Hydrologic consistency as a basis for

  9. The speed of memory errors shows the influence of misleading information: Testing the diffusion model and discrete-state models.

    Science.gov (United States)

    Starns, Jeffrey J; Dubé, Chad; Frelinger, Matthew E

    2018-05-01

    In this report, we evaluate single-item and forced-choice recognition memory for the same items and use the resulting accuracy and reaction time data to test the predictions of discrete-state and continuous models. For the single-item trials, participants saw a word and indicated whether or not it was studied on a previous list. The forced-choice trials had one studied and one non-studied word that both appeared in the earlier single-item trials and both received the same response. Thus, forced-choice trials always had one word with a previous correct response and one with a previous error. Participants were asked to select the studied word regardless of whether they previously called both words "studied" or "not studied." The diffusion model predicts that forced-choice accuracy should be lower when the word with a previous error had a fast versus a slow single-item RT, because fast errors are associated with more compelling misleading memory retrieval. The two-high-threshold (2HT) model does not share this prediction because all errors are guesses, so error RT is not related to memory strength. A low-threshold version of the discrete state approach predicts an effect similar to the diffusion model, because errors are a mixture of responses based on misleading retrieval and guesses, and the guesses should tend to be slower. Results showed that faster single-trial errors were associated with lower forced-choice accuracy, as predicted by the diffusion and low-threshold models. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. A self-consistent model for the electronic structure of the u-center in alkali-halides

    International Nuclear Information System (INIS)

    Koiller, B.; Brandi, H.S.

    1978-01-01

    A simple one-orbital per site model Hamiltonian for the U center in alkali-halides with rock-salt structure where correlation effects are introduced via an Anderson type Hamiltonian is presented. The Cluster-Bethe lattice method is used to determine the local density of states, yielding both localized and extended states. A one-electron approximation is assumed and the problem is solved self consistently in the Hartree-Fock scheme. The optical excitation energy is in fair agreement with experiment. The present approach is compared with other models previously used to describe this center and the results indicate that is adequately incorporates the relevant features of the system indicating the possibility of its application to other physical situations [pt

  11. Description of nucleon scattering on 208Pb by a fully Lane-consistent dispersive spherical optical model potential

    Science.gov (United States)

    Sun, W. L.; Wang, J.; Soukhovitskii, E. Sh.; Capote, R.; Quesada, J. M.

    2017-09-01

    A fully Lane-consistent dispersive spherical optical potential is proposed to describe nucleon scattering interaction with doubly magic nucleus 208Pb up to 200 MeV. The experimental neutron total cross sections, elastically scattered nucleon angular distributions and (p,n) data had been used to search the potential parameters. Good agreement between experiments and the calculations with this potential is observed. Meanwhile, the application of the determined optical potential with the same parameters to neighbouring near magic Pb-Bi isotopes is also examined to show the predictive power of this potential.

  12. Simple solvable energy-landscape model that shows a thermodynamic phase transition and a glass transition.

    Science.gov (United States)

    Naumis, Gerardo G

    2012-06-01

    When a liquid melt is cooled, a glass or phase transition can be obtained depending on the cooling rate. Yet, this behavior has not been clearly captured in energy-landscape models. Here, a model is provided in which two key ingredients are considered in the landscape, metastable states and their multiplicity. Metastable states are considered as in two level system models. However, their multiplicity and topology allows a phase transition in the thermodynamic limit for slow cooling, while a transition to the glass is obtained for fast cooling. By solving the corresponding master equation, the minimal speed of cooling required to produce the glass is obtained as a function of the distribution of metastable states.

  13. Modeled hydrologic metrics show links between hydrology and the functional composition of stream assemblages.

    Science.gov (United States)

    Patrick, Christopher J; Yuan, Lester L

    2017-07-01

    Flow alteration is widespread in streams, but current understanding of the effects of differences in flow characteristics on stream biological communities is incomplete. We tested hypotheses about the effect of variation in hydrology on stream communities by using generalized additive models to relate watershed information to the values of different flow metrics at gauged sites. Flow models accounted for 54-80% of the spatial variation in flow metric values among gauged sites. We then used these models to predict flow metrics in 842 ungauged stream sites in the mid-Atlantic United States that were sampled for fish, macroinvertebrates, and environmental covariates. Fish and macroinvertebrate assemblages were characterized in terms of a suite of metrics that quantified aspects of community composition, diversity, and functional traits that were expected to be associated with differences in flow characteristics. We related modeled flow metrics to biological metrics in a series of stressor-response models. Our analyses identified both drying and base flow instability as explaining 30-50% of the observed variability in fish and invertebrate community composition. Variations in community composition were related to variations in the prevalence of dispersal traits in invertebrates and trophic guilds in fish. The results demonstrate that we can use statistical models to predict hydrologic conditions at bioassessment sites, which, in turn, we can use to estimate relationships between flow conditions and biological characteristics. This analysis provides an approach to quantify the effects of spatial variation in flow metrics using readily available biomonitoring data. © 2017 by the Ecological Society of America.

  14. Interfacial tension and wettability in water-carbon dioxide systems: Experiments and self-consistent field modeling

    NARCIS (Netherlands)

    Banerjee, S.; Hassenklover, E.; Kleijn, J.M.; Cohen Stuart, M.A.; Leermakers, F.A.M.

    2013-01-01

    This paper presents experimental and modeling results on water–CO2 interfacial tension (IFT) together with wettability studies of water on both hydrophilic and hydrophobic surfaces immersed in CO2. CO2–water interfacial tension (IFT) measurements showed that the IFT decreased with increasing

  15. A Self-consistent Cloud Model for Brown Dwarfs and Young Giant Exoplanets: Comparison with Photometric and Spectroscopic Observations

    Science.gov (United States)

    Charnay, B.; Bézard, B.; Baudino, J.-L.; Bonnefoy, M.; Boccaletti, A.; Galicher, R.

    2018-02-01

    We developed a simple, physical, and self-consistent cloud model for brown dwarfs and young giant exoplanets. We compared different parametrizations for the cloud particle size, by fixing either particle radii or the mixing efficiency (parameter f sed), or by estimating particle radii from simple microphysics. The cloud scheme with simple microphysics appears to be the best parametrization by successfully reproducing the observed photometry and spectra of brown dwarfs and young giant exoplanets. In particular, it reproduces the L–T transition, due to the condensation of silicate and iron clouds below the visible/near-IR photosphere. It also reproduces the reddening observed for low-gravity objects, due to an increase of cloud optical depth for low gravity. In addition, we found that the cloud greenhouse effect shifts chemical equilibrium, increasing the abundances of species stable at high temperature. This effect should significantly contribute to the strong variation of methane abundance at the L–T transition and to the methane depletion observed on young exoplanets. Finally, we predict the existence of a continuum of brown dwarfs and exoplanets for absolute J magnitude = 15–18 and J-K color = 0–3, due to the evolution of the L–T transition with gravity. This self-consistent model therefore provides a general framework to understand the effects of clouds and appears well-suited for atmospheric retrievals.

  16. Producing physically consistent and bias free extreme precipitation events over the Switzerland: Bridging gaps between meteorology and impact models

    Science.gov (United States)

    José Gómez-Navarro, Juan; Raible, Christoph C.; Blumer, Sandro; Martius, Olivia; Felder, Guido

    2016-04-01

    Extreme precipitation episodes, although rare, are natural phenomena that can threat human activities, especially in areas densely populated such as Switzerland. Their relevance demands the design of public policies that protect public assets and private property. Therefore, increasing the current understanding of such exceptional situations is required, i.e. the climatic characterisation of their triggering circumstances, severity, frequency, and spatial distribution. Such increased knowledge shall eventually lead us to produce more reliable projections about the behaviour of these events under ongoing climate change. Unfortunately, the study of extreme situations is hampered by the short instrumental record, which precludes a proper characterization of events with return period exceeding few decades. This study proposes a new approach that allows studying storms based on a synthetic, but physically consistent database of weather situations obtained from a long climate simulation. Our starting point is a 500-yr control simulation carried out with the Community Earth System Model (CESM). In a second step, this dataset is dynamically downscaled with the Weather Research and Forecasting model (WRF) to a final resolution of 2 km over the Alpine area. However, downscaling the full CESM simulation at such high resolution is infeasible nowadays. Hence, a number of case studies are previously selected. This selection is carried out examining the precipitation averaged in an area encompassing Switzerland in the ESM. Using a hydrological criterion, precipitation is accumulated in several temporal windows: 1 day, 2 days, 3 days, 5 days and 10 days. The 4 most extreme events in each category and season are selected, leading to a total of 336 days to be simulated. The simulated events are affected by systematic biases that have to be accounted before this data set can be used as input in hydrological models. Thus, quantile mapping is used to remove such biases. For this task

  17. A self-consistent model of a thermally balanced quiescent prominence in magnetostatic equilibrium in a uniform gravitational field

    International Nuclear Information System (INIS)

    Lerche, I.; Low, B.C.

    1977-01-01

    A theoretical model of quiescent prominences in the form of an infinite vertical sheet is presented. Self-consistent solutions are obtained by integrating simultaneously the set of nonlinear equations of magnetostatic equilibrium and thermal balance. The basic features of the models are: (1) The prominence matter is confined to a sheet and supported against gravity by a bowed magnetic field. (2) The thermal flux is channelled along magnetic field lines. (3) The thermal flux is everywhere balanced by Low's (1975) hypothetical heat sink which is proportional to the local density. (4) A constant component of the magnetic field along the length of the prominence shields the cool plasma from the hot surrounding. It is assumed that the prominence plasma emits more radiation than it absorbes from the radiation fields of the photosphere, chromosphere and corona, and the above hypothetical heat sink is interpreted to represent the amount of radiative loss that must be balanced by a nonradiative energy input. Using a central density and temperature of 10 11 particles cm -3 and 5000 K respectively, a magnetic field strength between 2 to 10 gauss and a thermal conductivity that varies linearly with temperature, the physical properties implied by the model are discussed. The analytic treatment can also be carried out for a class of more complex thermal conductivities. These models provide a useful starting point for investigating the combined requirements of magnetostatic equilibrium and thermal balance in the quiescent prominence. (Auth.)

  18. Animal Models for Muscular Dystrophy Show Different Patterns of Sarcolemmal Disruption

    OpenAIRE

    Straub, Volker; Rafael, Jill A.; Chamberlain, Jeffrey S.; Campbell, Kevin P.

    1997-01-01

    Genetic defects in a number of components of the dystrophin–glycoprotein complex (DGC) lead to distinct forms of muscular dystrophy. However, little is known about how alterations in the DGC are manifested in the pathophysiology present in dystrophic muscle tissue. One hypothesis is that the DGC protects the sarcolemma from contraction-induced damage. Using tracer molecules, we compared sarcolemmal integrity in animal models for muscular dystrophy and in muscular dystrophy patient samples. Ev...

  19. The PROMETHEUS bundled payment experiment: slow start shows problems in implementing new payment models.

    Science.gov (United States)

    Hussey, Peter S; Ridgely, M Susan; Rosenthal, Meredith B

    2011-11-01

    Fee-for-service payment is blamed for many of the problems observed in the US health care system. One of the leading alternative payment models proposed in the Affordable Care Act of 2010 is bundled payment, which provides payment for all of the care a patient needs over the course of a defined clinical episode, instead of paying for each discrete service. We evaluated the initial "road test" of PROMETHEUS Payment, one of several bundled payment pilot projects. The project has faced substantial implementation challenges, and none of the three pilot sites had executed contracts or made bundled payments as of May 2011. The pilots have taken longer to set up than expected, primarily because of the complexity of the payment model and the fact that it builds on the existing fee-for-service payment system and other complexities of health care. Participants continue to see promise and value in the bundled payment model, but the pilot results suggest that the desired benefits of this and other payment reforms may take time and considerable effort to materialize.

  20. Global thermal niche models of two European grasses show high invasion risks in Antarctica.

    Science.gov (United States)

    Pertierra, Luis R; Aragón, Pedro; Shaw, Justine D; Bergstrom, Dana M; Terauds, Aleks; Olalla-Tárraga, Miguel Ángel

    2017-07-01

    The two non-native grasses that have established long-term populations in Antarctica (Poa pratensis and Poa annua) were studied from a global multidimensional thermal niche perspective to address the biological invasion risk to Antarctica. These two species exhibit contrasting introduction histories and reproductive strategies and represent two referential case studies of biological invasion processes. We used a multistep process with a range of species distribution modelling techniques (ecological niche factor analysis, multidimensional envelopes, distance/entropy algorithms) together with a suite of thermoclimatic variables, to characterize the potential ranges of these species. Their native bioclimatic thermal envelopes in Eurasia, together with the different naturalized populations across continents, were compared next. The potential niche of P. pratensis was wider at the cold extremes; however, P. annua life history attributes enable it to be a more successful colonizer. We observe that particularly cold summers are a key aspect of the unique Antarctic environment. In consequence, ruderals such as P. annua can quickly expand under such harsh conditions, whereas the more stress-tolerant P. pratensis endures and persist through steady growth. Compiled data on human pressure at the Antarctic Peninsula allowed us to provide site-specific biosecurity risk indicators. We conclude that several areas across the region are vulnerable to invasions from these and other similar species. This can only be visualized in species distribution models (SDMs) when accounting for founder populations that reveal nonanalogous conditions. Results reinforce the need for strict management practices to minimize introductions. Furthermore, our novel set of temperature-based bioclimatic GIS layers for ice-free terrestrial Antarctica provide a mechanism for regional and global species distribution models to be built for other potentially invasive species. © 2017 John Wiley & Sons Ltd.

  1. ASIC1a Deficient Mice Show Unaltered Neurodegeneration in the Subacute MPTP Model of Parkinson Disease.

    Science.gov (United States)

    Komnig, Daniel; Imgrund, Silke; Reich, Arno; Gründer, Stefan; Falkenburger, Björn H

    2016-01-01

    Inflammation contributes to the death of dopaminergic neurons in Parkinson disease and can be accompanied by acidification of extracellular pH, which may activate acid-sensing ion channels (ASIC). Accordingly, amiloride, a non-selective inhibitor of ASIC, was protective in an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson disease. To complement these findings we determined MPTP toxicity in mice deficient for ASIC1a, the most common ASIC isoform in neurons. MPTP was applied i.p. in doses of 30 mg per kg on five consecutive days. We determined the number of dopaminergic neurons in the substantia nigra, assayed by stereological counting 14 days after the last MPTP injection, the number of Nissl positive neurons in the substantia nigra, and the concentration of catecholamines in the striatum. There was no difference between ASIC1a-deficient mice and wildtype controls. We are therefore not able to confirm that ASIC1a are involved in MPTP toxicity. The difference might relate to the subacute MPTP model we used, which more closely resembles the pathogenesis of Parkinson disease, or to further targets of amiloride.

  2. Progesterone treatment shows benefit in a pediatric model of moderate to severe bilateral brain injury.

    Directory of Open Access Journals (Sweden)

    Rastafa I Geddes

    Full Text Available Controlled cortical impact (CCI models in adult and aged Sprague-Dawley (SD rats have been used extensively to study medial prefrontal cortex (mPFC injury and the effects of post-injury progesterone treatment, but the hormone's effects after traumatic brain injury (TBI in juvenile animals have not been determined. In the present proof-of-concept study we investigated whether progesterone had neuroprotective effects in a pediatric model of moderate to severe bilateral brain injury.Twenty-eight-day old (PND 28 male Sprague Dawley rats received sham (n = 24 or CCI (n = 47 injury and were given progesterone (4, 8, or 16 mg/kg per 100 g body weight or vehicle injections on post-injury days (PID 1-7, subjected to behavioral testing from PID 9-27, and analyzed for lesion size at PID 28.The 8 and 16 mg/kg doses of progesterone were observed to be most beneficial in reducing the effect of CCI on lesion size and behavior in PND 28 male SD rats.Our findings suggest that a midline CCI injury to the frontal cortex will reliably produce a moderate TBI comparable to what is seen in the adult male rat and that progesterone can ameliorate the injury-induced deficits.

  3. ASIC1a Deficient Mice Show Unaltered Neurodegeneration in the Subacute MPTP Model of Parkinson Disease.

    Directory of Open Access Journals (Sweden)

    Daniel Komnig

    Full Text Available Inflammation contributes to the death of dopaminergic neurons in Parkinson disease and can be accompanied by acidification of extracellular pH, which may activate acid-sensing ion channels (ASIC. Accordingly, amiloride, a non-selective inhibitor of ASIC, was protective in an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP mouse model of Parkinson disease. To complement these findings we determined MPTP toxicity in mice deficient for ASIC1a, the most common ASIC isoform in neurons. MPTP was applied i.p. in doses of 30 mg per kg on five consecutive days. We determined the number of dopaminergic neurons in the substantia nigra, assayed by stereological counting 14 days after the last MPTP injection, the number of Nissl positive neurons in the substantia nigra, and the concentration of catecholamines in the striatum. There was no difference between ASIC1a-deficient mice and wildtype controls. We are therefore not able to confirm that ASIC1a are involved in MPTP toxicity. The difference might relate to the subacute MPTP model we used, which more closely resembles the pathogenesis of Parkinson disease, or to further targets of amiloride.

  4. Self-Consistant Numerical Modeling of E-Cloud Driven Instability of a Bunch Train in the CERN SPS

    International Nuclear Information System (INIS)

    Vay, J.-L.; Furman, M.A.; Secondo, R.; Venturini, M.; Fox, J.D.; Rivetta, C.H.

    2010-01-01

    The simulation package WARP-POSINST was recently upgraded for handling multiple bunches and modeling concurrently the electron cloud buildup and its effect on the beam, allowing for direct self-consistent simulation of bunch trains generating, and interacting with, electron clouds. We have used the WARP-POSINST package on massively parallel supercomputers to study the growth rate and frequency patterns in space-time of the electron cloud driven transverse instability for a proton bunch train in the CERN SPS accelerator. Results suggest that a positive feedback mechanism exists between the electron buildup and the e-cloud driven transverse instability, leading to a net increase in predicted electron density. Comparisons to selected experimental data are also given. Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS and other accelerators. So far, simulations of electron cloud buildup and their effects on beam dynamics have been performed separately. This is a consequence of the large computational cost of the combined calculation due to large space and time scale disparities between the two processes. We have presented the latest improvements of the simulation package WARP-POSINST for the simulation of self-consistent ecloud effects, including mesh refinement, and generation of electrons from gas ionization and impact at the pipe walls. We also presented simulations of two consecutive bunches interacting with electrons clouds in the SPS, which included generation of secondary electrons. The distribution of electrons in front of the first beam was initialized from a dump taken from a preceding buildup calculation using the POSINST code. In this paper, we present an extension of this work where one full batch of 72 bunches is simulated in the SPS, including the entire buildup calculation and the self-consistent interaction between the bunches and the electrons. Comparisons to experimental data are also given.

  5. A self-consistent trapping model of driven electron plasma waves and limits on stimulated Raman scatter

    International Nuclear Information System (INIS)

    Rose, Harvey A.; Russell, David A.

    2001-01-01

    A Vlasov equation based model is used to determine various regimes of electron plasma wave response to a source appropriate to stimulated scatter in a laser hot spot. It incorporates trapped particle effects such as the standard nonlinear frequency shift, extended beyond the weak regime, and a reduction of damping a la Zakharov and Karpman [V. E. Zakharov and V. I. Karpman, JETP 16, 351 (1963)]. The results are consistent with those of Holloway and Dorning [J. P. Holloway and J. J. Dorning, Phys. Rev. A 44, 3856 (1991)] for small amplitude Bernstein-Greene-Kruskal modes. This leads to the prediction that as long as kλ D ≥0.53 for a background Maxwellian distribution function, e.g., a 5 keV plasma with n e /n c ≤0.075, anomalously large backward stimulated Raman scatter can be excluded. A similar analysis leads to density limits on stimulated Brillouin scatter

  6. A zebrafish model of glucocorticoid resistance shows serotonergic modulation of the stress response

    Directory of Open Access Journals (Sweden)

    Brian eGriffiths

    2012-10-01

    Full Text Available One function of glucocorticoids is to restore homeostasis after an acute stress response by providing negative feedback to stress circuits in the brain. Loss of this negative feedback leads to elevated physiological stress and may contribute to depression, anxiety and post-traumatic stress disorder. We investigated the early, developmental effects of glucocorticoid signaling deficits on stress physiology and related behaviors using a mutant zebrafish, grs357, with non-functional glucocorticoid receptors. These mutants are morphologically inconspicuous and adult-viable. A previous study of adult grs357 mutants showed loss of glucocorticoid-mediated negative feedback and elevated physiological and behavioral stress markers. Already at five days post-fertilization, mutant larvae had elevated whole body cortisol, increased expression of pro-opiomelanocortin (POMC, the precursor of adrenocorticotropic hormone (ACTH, and failed to show normal suppression of stress markers after dexamethasone treatment. Mutant larvae had larger auditory-evoked startle responses compared to wildtype sibling controls (grwt, despite having lower spontaneous activity levels. Fluoxetine (Prozac treatment in mutants decreased startle responding and increased spontaneous activity, making them behaviorally similar to wildtype. This result mirrors known effects of selective serotonin reuptake inhibitors (SSRIs in modifying glucocorticoid signaling and alleviating stress disorders in human patients. Our results suggest that larval grs357 zebrafish can be used to study behavioral, physiological and molecular aspects of stress disorders. Most importantly, interactions between glucocorticoid and serotonin signaling appear to be highly conserved among vertebrates, suggesting deep homologies at the neural circuit level and opening up new avenues for research into psychiatric conditions.

  7. Metabolic remodeling agents show beneficial effects in the dystrophin-deficient mdx mouse model

    Directory of Open Access Journals (Sweden)

    Jahnke Vanessa E

    2012-08-01

    Full Text Available Abstract Background Duchenne muscular dystrophy is a genetic disease involving a severe muscle wasting that is characterized by cycles of muscle degeneration/regeneration and culminates in early death in affected boys. Mitochondria are presumed to be involved in the regulation of myoblast proliferation/differentiation; enhancing mitochondrial activity with exercise mimetics (AMPK and PPAR-delta agonists increases muscle function and inhibits muscle wasting in healthy mice. We therefore asked whether metabolic remodeling agents that increase mitochondrial activity would improve muscle function in mdx mice. Methods Twelve-week-old mdx mice were treated with two different metabolic remodeling agents (GW501516 and AICAR, separately or in combination, for 4 weeks. Extensive systematic behavioral, functional, histological, biochemical, and molecular tests were conducted to assess the drug(s' effects. Results We found a gain in body and muscle weight in all treated mice. Histologic examination showed a decrease in muscle inflammation and in the number of fibers with central nuclei and an increase in fibers with peripheral nuclei, with significantly fewer activated satellite cells and regenerating fibers. Together with an inhibition of FoXO1 signaling, these results indicated that the treatments reduced ongoing muscle damage. Conclusions The three treatments produced significant improvements in disease phenotype, including an increase in overall behavioral activity and significant gains in forelimb and hind limb strength. Our findings suggest that triggering mitochondrial activity with exercise mimetics improves muscle function in dystrophin-deficient mdx mice.

  8. Male Wistar rats show individual differences in an animal model of conformity.

    Science.gov (United States)

    Jolles, Jolle W; de Visser, Leonie; van den Bos, Ruud

    2011-09-01

    Conformity refers to the act of changing one's behaviour to match that of others. Recent studies in humans have shown that individual differences exist in conformity and that these differences are related to differences in neuronal activity. To understand the neuronal mechanisms in more detail, animal tests to assess conformity are needed. Here, we used a test of conformity in rats that has previously been evaluated in female, but not male, rats and assessed the nature of individual differences in conformity. Male Wistar rats were given the opportunity to learn that two diets differed in palatability. They were subsequently exposed to a demonstrator that had consumed the less palatable food. Thereafter, they were exposed to the same diets again. Just like female rats, male rats decreased their preference for the more palatable food after interaction with demonstrator rats that had eaten the less palatable food. Individual differences existed for this shift, which were only weakly related to an interaction between their own initial preference and the amount consumed by the demonstrator rat. The data show that this conformity test in rats is a promising tool to study the neurobiology of conformity.

  9. Modeling serotonin uptake in the lung shows endothelial transporters dominate over cleft permeation

    Science.gov (United States)

    Bassingthwaighte, James B.

    2013-01-01

    A four-region (capillary plasma, endothelium, interstitial fluid, cell) multipath model was configured to describe the kinetics of blood-tissue exchange for small solutes in the lung, accounting for regional flow heterogeneity, permeation of cell membranes and through interendothelial clefts, and intracellular reactions. Serotonin uptake data from the Multiple indicator dilution “bolus sweep” experiments of Rickaby and coworkers (Rickaby DA, Linehan JH, Bronikowski TA, Dawson CA. J Appl Physiol 51: 405–414, 1981; Rickaby DA, Dawson CA, and Linehan JH. J Appl Physiol 56: 1170–1177, 1984) and Malcorps et al. (Malcorps CM, Dawson CA, Linehan JH, Bronikowski TA, Rickaby DA, Herman AG, Will JA. J Appl Physiol 57: 720–730, 1984) were analyzed to distinguish facilitated transport into the endothelial cells (EC) and the inhibition of tracer transport by nontracer serotonin in the bolus of injectate from the free uninhibited permeation through the clefts into the interstitial fluid space. The permeability-surface area products (PS) for serotonin via the inter-EC clefts were ∼0.3 ml·g−1·min−1, low compared with the transporter-mediated maximum PS of 13 ml·g−1·min−1 (with Km = ∼0.3 μM and Vmax = ∼4 nmol·g−1·min−1). The estimates of serotonin PS values for EC transporters from their multiple data sets were similar and were influenced only modestly by accounting for the cleft permeability in parallel. The cleft PS estimates in these Ringer-perfused lungs are less than half of those for anesthetized dogs (Yipintsoi T. Circ Res 39: 523–531, 1976) with normal hematocrits, but are compatible with passive noncarrier-mediated transport observed later in the same laboratory (Dawson CA, Linehan JH, Rickaby DA, Bronikowski TA. Ann Biomed Eng 15: 217–227, 1987; Peeters FAM, Bronikowski TA, Dawson CA, Linehan JH, Bult H, Herman AG. J Appl Physiol 66: 2328–2337, 1989) The identification and quantitation of the cleft pathway conductance from these

  10. Self-consistent fluid modeling and simulation on a pulsed microwave atmospheric-pressure argon plasma jet

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhaoquan, E-mail: zqchen@aust.edu.cn [Faculty of Physics, St. Petersburg State University, St. Petersburg 198504 (Russian Federation); College of Electrical and Information Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001 (China); Yin, Zhixiang, E-mail: zxyin66@163.com; Chen, Minggong; Hong, Lingli; Hu, Yelin; Huang, Yourui [College of Electrical and Information Engineering, Anhui University of Science and Technology, Huainan, Anhui 232001 (China); Xia, Guangqing; Liu, Minghai [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Kudryavtsev, A. A. [Faculty of Physics, St. Petersburg State University, St. Petersburg 198504 (Russian Federation)

    2014-10-21

    In present study, a pulsed lower-power microwave-driven atmospheric-pressure argon plasma jet has been introduced with the type of coaxial transmission line resonator. The plasma jet plume is with room air temperature, even can be directly touched by human body without any hot harm. In order to study ionization process of the proposed plasma jet, a self-consistent hybrid fluid model is constructed in which Maxwell's equations are solved numerically by finite-difference time-domain method and a fluid model is used to study the characteristics of argon plasma evolution. With a Guass type input power function, the spatio-temporal distributions of the electron density, the electron temperature, the electric field, and the absorbed power density have been simulated, respectively. The simulation results suggest that the peak values of the electron temperature and the electric field are synchronous with the input pulsed microwave power but the maximum quantities of the electron density and the absorbed power density are lagged to the microwave power excitation. In addition, the pulsed plasma jet excited by the local enhanced electric field of surface plasmon polaritons should be the discharge mechanism of the proposed plasma jet.

  11. Thermodynamics of a Compressible Maier-Saupe Model Based on the Self-Consistent Field Theory of Wormlike Polymer

    Directory of Open Access Journals (Sweden)

    Ying Jiang

    2017-02-01

    Full Text Available This paper presents a theoretical formalism for describing systems of semiflexible polymers, which can have density variations due to finite compressibility and exhibit an isotropic-nematic transition. The molecular architecture of the semiflexible polymers is described by a continuum wormlike-chain model. The non-bonded interactions are described through a functional of two collective variables, the local density and local segmental orientation tensor. In particular, the functional depends quadratically on local density-variations and includes a Maier–Saupe-type term to deal with the orientational ordering. The specified density-dependence stems from a free energy expansion, where the free energy of an isotropic and homogeneous homopolymer melt at some fixed density serves as a reference state. Using this framework, a self-consistent field theory is developed, which produces a Helmholtz free energy that can be used for the calculation of the thermodynamics of the system. The thermodynamic properties are analysed as functions of the compressibility of the model, for values of the compressibility realizable in mesoscopic simulations with soft interactions and in actual polymeric materials.

  12. Self-consistent modelling of lattice strains during the in-situ tensile loading of twinning induced plasticity steel

    International Nuclear Information System (INIS)

    Saleh, Ahmed A.; Pereloma, Elena V.; Clausen, Bjørn; Brown, Donald W.; Tomé, Carlos N.; Gazder, Azdiar A.

    2014-01-01

    The evolution of lattice strains in a fully recrystallised Fe–24Mn–3Al–2Si–1Ni–0.06C TWinning Induced Plasticity (TWIP) steel subjected to uniaxial tensile loading up to a true strain of ∼35% was investigated via in-situ neutron diffraction. Typical of fcc elastic and plastic anisotropy, the {111} and {200} grain families record the lowest and highest lattice strains, respectively. Using modelling cases with and without latent hardening, the recently extended Elasto-Plastic Self-Consistent model successfully predicted the macroscopic stress–strain response, the evolution of lattice strains and the development of crystallographic texture. Compared to the isotropic hardening case, latent hardening did not have a significant effect on lattice strains and returned a relatively faster development of a stronger 〈111〉 and a weaker 〈100〉 double fibre parallel to the tensile axis. Close correspondence between the experimental lattice strains and those predicted using particular orientations embedded within a random aggregate was obtained. The result suggests that the exact orientations of the surrounding aggregate have a weak influence on the lattice strain evolution

  13. Development of a Self-Consistent Model of Plutonium Sorption: Quantification of Sorption Enthalpy and Ligand-Promoted Dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Powell, Brian [Clemson Univ., SC (United States); Kaplan, Daniel I [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Arai, Yuji [Univ. of Illinois, Urbana-Champaign, IL (United States); Becker, Udo [Univ. of Michigan, Ann Arbor, MI (United States); Ewing, Rod [Stanford Univ., CA (United States)

    2016-12-29

    This university lead SBR project is a collaboration lead by Dr. Brian Powell (Clemson University) with co-principal investigators Dan Kaplan (Savannah River National Laboratory), Yuji Arai (presently at the University of Illinois), Udo Becker (U of Michigan) and Rod Ewing (presently at Stanford University). Hypothesis: The underlying hypothesis of this work is that strong interactions of plutonium with mineral surfaces are due to formation of inner sphere complexes with a limited number of high-energy surface sites, which results in sorption hysteresis where Pu(IV) is the predominant sorbed oxidation state. The energetic favorability of the Pu(IV) surface complex is strongly influenced by positive sorption entropies, which are mechanistically driven by displacement of solvating water molecules from the actinide and mineral surface during sorption. Objectives: The overarching objective of this work is to examine Pu(IV) and Pu(V) sorption to pure metal (oxyhydr)oxide minerals and sediments using variable temperature batch sorption, X-ray absorption spectroscopy, electron microscopy, and quantum-mechanical and empirical-potential calculations. The data will be compiled into a self-consistent surface complexation model. The novelty of this effort lies largely in the manner the information from these measurements and calculations will be combined into a model that will be used to evaluate the thermodynamics of plutonium sorption reactions as well as predict sorption of plutonium to sediments from DOE sites using a component additivity approach.

  14. A NEW ALGORITHM FOR SELF-CONSISTENT THREE-DIMENSIONAL MODELING OF COLLISIONS IN DUSTY DEBRIS DISKS

    International Nuclear Information System (INIS)

    Stark, Christopher C.; Kuchner, Marc J.

    2009-01-01

    We present a new 'collisional grooming' algorithm that enables us to model images of debris disks where the collision time is less than the Poynting-Robertson (PR) time for the dominant grain size. Our algorithm uses the output of a collisionless disk simulation to iteratively solve the mass flux equation for the density distribution of a collisional disk containing planets in three dimensions. The algorithm can be run on a single processor in ∼1 hr. Our preliminary models of disks with resonant ring structures caused by terrestrial mass planets show that the collision rate for background particles in a ring structure is enhanced by a factor of a few compared to the rest of the disk, and that dust grains in or near resonance have even higher collision rates. We show how collisions can alter the morphology of a resonant ring structure by reducing the sharpness of a resonant ring's inner edge and by smearing out azimuthal structure. We implement a simple prescription for particle fragmentation and show how PR drag and fragmentation sort particles by size, producing smaller dust grains at smaller circumstellar distances. This mechanism could cause a disk to look different at different wavelengths, and may explain the warm component of dust interior to Fomalhaut's outer dust ring seen in the resolved 24 μm Spitzer image of this system.

  15. Development of new pedestal temperature models with self-consistent magnetic shear and safety factor in BALDUR and JETTO codes

    International Nuclear Information System (INIS)

    Suwanna, S.; Onjun, T.; Wongpan, P.; Parail, V.; Poolyarat, N.; Picha, R.

    2009-01-01

    Full text: A formation of a steep pressure gradient region near the plasma edge, called the pedestal, is a main reason for an improved performance in H-mode plasma. In this work, new pedestal temperature models are developed based on different theoretical-based width concepts: flow shear stabilization width concept, magnetic and flow shear stabilization width concept, and diamagnetic stabilization width concept. In the BALDUR code, each pedestal width model is combined with a ballooning mode pressure gradient model to predict the pedestal temperature, which is a boundary condition needed to predict plasma profiles. In the JETTO code, an anomalous transport is suppressed within the pedestal region, which results in a formation of a steep pressure gradient region. The pedestal width is predicted using these theoretically based width concepts. The plasma profiles in the pedestal region are limited by ELM crashes, which can be triggered either by ballooning modes or by peeling modes, depending on which instability is destabilized first. It is found in the BALDUR simulations that the simulated pedestal temperature profiles agree well with experimental data in the region close to the pedestal, but show larger deviation in the core region. In a preliminary investigation, these models agree reasonably well with experiments, yielding overall RMS less than 20%. Furthermore, the model based flow shear stabilization matches very well data from both DIII-D and JET, while the model based on magnetic and flow shear stabilization over-predicts results from JET and under-predicts those from DIII-D. Other statistical analyses such a calculation of offset values, ratios of predicted pedestal (resp. core) temperatures to those from experiments are performed. (author)

  16. KEEFEKTIFAN MODEL SHOW NOT TELL DAN MIND MAP PADA PEMBELAJARAN MENULIS TEKS EKSPOSISI BERDASARKAN MINAT PESERTA DIDIK KELAS X SMK

    Directory of Open Access Journals (Sweden)

    Wiwit Lili Sokhipah

    2015-03-01

    Full Text Available Tujuan penelitian ini adalah (1 menentukan keefektifan penggunaan model show not tell pada pembelajaran keterampilan menulis teks eksposisi berdasarkan minat peserta didik SMK Kelas X, (2 menentukan keefektifan penggunaan model mind map pada pembelajaran keterampilan menulis teks eksposisi berdasarkan minat peserta didik SMK kelas X, (3 menentukan keefektifan interaksi show not tell dan mind map pada pembelajaran keterampilan menulis teks eksposisi berdasarkan minat peserta didik SMK kelas X. Penelitian ini adalah quasi experimental design (pretes-postes control group design. Dalam desain ini terdapat dua kelompok eksperimen yakni penerapan model show not tell dalam pembelajaran keterampilan menulis teks eksposisipeserta didik dengan minat tinggi dan penerapan model mind map dalam pembelajaran keterampilan menulis teks eksposisi  peserta didik dengan minat rendah. Hasil penelitian adalah (1 model show not tell efektif digunakan  dalam membelajarkan menulis teks eksposisi bagi peserta didik yang memiliki minat tinggi, (2 model mind map efektif digunakan dalam membelajarkan menulis teks eksposisi bagi peserta didik yang memiliki minat rendah, dan (3 model show not tell lebih efektif digunakan dalam membelajarkan menulis teks eksposisi bagi peserta didik yang memiliki minat tinggi, sedangkan model mind map efektif digunakan dalam membelajarkan teks eksposisi pagi peserta didik yang memiliki minat rendah.

  17. Evaluating statistical consistency in the ocean model component of the Community Earth System Model (pyCECT v2.0)

    Science.gov (United States)

    Baker, Allison H.; Hu, Yong; Hammerling, Dorit M.; Tseng, Yu-heng; Xu, Haiying; Huang, Xiaomeng; Bryan, Frank O.; Yang, Guangwen

    2016-07-01

    The Parallel Ocean Program (POP), the ocean model component of the Community Earth System Model (CESM), is widely used in climate research. Most current work in CESM-POP focuses on improving the model's efficiency or accuracy, such as improving numerical methods, advancing parameterization, porting to new architectures, or increasing parallelism. Since ocean dynamics are chaotic in nature, achieving bit-for-bit (BFB) identical results in ocean solutions cannot be guaranteed for even tiny code modifications, and determining whether modifications are admissible (i.e., statistically consistent with the original results) is non-trivial. In recent work, an ensemble-based statistical approach was shown to work well for software verification (i.e., quality assurance) on atmospheric model data. The general idea of the ensemble-based statistical consistency testing is to use a qualitative measurement of the variability of the ensemble of simulations as a metric with which to compare future simulations and make a determination of statistical distinguishability. The capability to determine consistency without BFB results boosts model confidence and provides the flexibility needed, for example, for more aggressive code optimizations and the use of heterogeneous execution environments. Since ocean and atmosphere models have differing characteristics in term of dynamics, spatial variability, and timescales, we present a new statistical method to evaluate ocean model simulation data that requires the evaluation of ensemble means and deviations in a spatial manner. In particular, the statistical distribution from an ensemble of CESM-POP simulations is used to determine the standard score of any new model solution at each grid point. Then the percentage of points that have scores greater than a specified threshold indicates whether the new model simulation is statistically distinguishable from the ensemble simulations. Both ensemble size and composition are important. Our

  18. Maier-Saupe model of polymer nematics: Comparing free energies calculated with Self Consistent Field theory and Monte Carlo simulations.

    Science.gov (United States)

    Greco, Cristina; Jiang, Ying; Chen, Jeff Z Y; Kremer, Kurt; Daoulas, Kostas Ch

    2016-11-14

    Self Consistent Field (SCF) theory serves as an efficient tool for studying mesoscale structure and thermodynamics of polymeric liquid crystals (LC). We investigate how some of the intrinsic approximations of SCF affect the description of the thermodynamics of polymeric LC, using a coarse-grained model. Polymer nematics are represented as discrete worm-like chains (WLC) where non-bonded interactions are defined combining an isotropic repulsive and an anisotropic attractive Maier-Saupe (MS) potential. The range of the potentials, σ, controls the strength of correlations due to non-bonded interactions. Increasing σ (which can be seen as an increase of coarse-graining) while preserving the integrated strength of the potentials reduces correlations. The model is studied with particle-based Monte Carlo (MC) simulations and SCF theory which uses partial enumeration to describe discrete WLC. In MC simulations the Helmholtz free energy is calculated as a function of strength of MS interactions to obtain reference thermodynamic data. To calculate the free energy of the nematic branch with respect to the disordered melt, we employ a special thermodynamic integration (TI) scheme invoking an external field to bypass the first-order isotropic-nematic transition. Methodological aspects which have not been discussed in earlier implementations of the TI to LC are considered. Special attention is given to the rotational Goldstone mode. The free-energy landscape in MC and SCF is directly compared. For moderate σ the differences highlight the importance of local non-bonded orientation correlations between segments, which SCF neglects. Simple renormalization of parameters in SCF cannot compensate the missing correlations. Increasing σ reduces correlations and SCF reproduces well the free energy in MC simulations.

  19. Self-consistent modeling of induced magnetic field in Titan's atmosphere accounting for the generation of Schumann resonance

    Science.gov (United States)

    Béghin, Christian

    2015-02-01

    This model is worked out in the frame of physical mechanisms proposed in previous studies accounting for the generation and the observation of an atypical Schumann Resonance (SR) during the descent of the Huygens Probe in the Titan's atmosphere on 14 January 2005. While Titan is staying inside the subsonic co-rotating magnetosphere of Saturn, a secondary magnetic field carrying an Extremely Low Frequency (ELF) modulation is shown to be generated through ion-acoustic instabilities of the Pedersen current sheets induced at the interface region between the impacting magnetospheric plasma and Titan's ionosphere. The stronger induced magnetic field components are focused within field-aligned arcs-like structures hanging down the current sheets, with minimum amplitude of about 0.3 nT throughout the ramside hemisphere from the ionopause down to the Moon surface, including the icy crust and its interface with a conductive water ocean. The deep penetration of the modulated magnetic field in the atmosphere is thought to be allowed thanks to the force balance between the average temporal variations of thermal and magnetic pressures within the field-aligned arcs. However, there is a first cause of diffusion of the ELF magnetic components, probably due to feeding one, or eventually several SR eigenmodes. A second leakage source is ascribed to a system of eddy-Foucault currents assumed to be induced through the buried water ocean. The amplitude spectrum distribution of the induced ELF magnetic field components inside the SR cavity is found fully consistent with the measurements of the Huygens wave-field strength. Waiting for expected future in-situ exploration of Titan's lower atmosphere and the surface, the Huygens data are the only experimental means available to date for constraining the proposed model.

  20. Intramolecular structures in a single copolymer chain consisting of flexible and semiflexible blocks: Monte Carlo simulation of a lattice model

    International Nuclear Information System (INIS)

    Martemyanova, Julia A; Ivanov, Victor A; Paul, Wolfgang

    2014-01-01

    We study conformational properties of a single multiblock copolymer chain consisting of flexible and semiflexible blocks. Monomer units of different blocks are equivalent in the sense of the volume interaction potential, but the intramolecular bending potential between successive bonds along the chain is different. We consider a single flexible-semiflexible regular multiblock copolymer chain with equal content of flexible and semiflexible units and vary the length of the blocks and the stiffness parameter. We perform flat histogram type Monte Carlo simulations based on the Wang-Landau approach and employ the bond fluctuation lattice model. We present here our data on different non-trivial globular morphologies which we have obtained in our model for different values of the block length and the stiffness parameter. We demonstrate that the collapse can occur in one or in two stages depending on the values of both these parameters and discuss the role of the inhomogeneity of intraglobular distributions of monomer units of both flexible and semiflexible blocks. For short block length and/or large stiffness the collapse occurs in two stages, because it goes through intermediate (meta-)stable structures, like a dumbbell shaped conformation. In such conformations the semiflexible blocks form a cylinder-like core, and the flexible blocks form two domains at both ends of such a cylinder. For long block length and/or small stiffness the collapse occurs in one stage, and in typical conformations the flexible blocks form a spherical core of a globule while the semiflexible blocks are located on the surface and wrap around this core.

  1. The KBC Void: Consistency with Supernovae Type Ia and the Kinematic SZ Effect in a ΛLTB Model

    Science.gov (United States)

    Hoscheit, Benjamin L.; Barger, Amy J.

    2018-02-01

    There is substantial and growing observational evidence from the normalized luminosity density in the near-infrared that the local universe is underdense on scales of several hundred megaparsecs. We test whether our parameterization of the observational data of such a “void” is compatible with the latest supernovae type Ia data and with constraints from line-of-sight peculiar-velocity motions of galaxy clusters with respect to the cosmic microwave background rest-frame, known as the linear kinematic Sunyaev–Zel’dovich (kSZ) effect. Our study is based on the large local void (LLV) radial profile observed by Keenan, Barger, and Cowie (KBC) and a theoretical void description based on the Lemaître–Tolman–Bondi model with a nonzero cosmological constant (ΛLTB). We find consistency with the measured luminosity distance–redshift relation on radial scales relevant to the KBC LLV through a comparison with 217 low-redshift supernovae type Ia over the redshift range 0.0233Cosmology Telescope, are fully compatible with the existence of the KBC LLV.

  2. Open-ended formulation of self-consistent field response theory with the polarizable continuum model for solvation.

    Science.gov (United States)

    Di Remigio, Roberto; Beerepoot, Maarten T P; Cornaton, Yann; Ringholm, Magnus; Steindal, Arnfinn Hykkerud; Ruud, Kenneth; Frediani, Luca

    2016-12-21

    The study of high-order absorption properties of molecules is a field of growing importance. Quantum-chemical studies can help design chromophores with desirable characteristics. Given that most experiments are performed in solution, it is important to devise a cost-effective strategy to include solvation effects in quantum-chemical studies of these properties. We here present an open-ended formulation of self-consistent field (SCF) response theory for a molecular solute coupled to a polarizable continuum model (PCM) description of the solvent. Our formulation relies on the open-ended, density matrix-based quasienergy formulation of SCF response theory of Thorvaldsen, et al., [J. Chem. Phys., 2008, 129, 214108] and the variational formulation of the PCM, as presented by Lipparini et al., [J. Chem. Phys., 2010, 133, 014106]. Within the PCM approach to solvation, the mutual solute-solvent polarization is represented by means of an apparent surface charge (ASC) spread over the molecular cavity defining the solute-solvent boundary. In the variational formulation, the ASC is an independent, variational degree of freedom. This allows us to formulate response theory for molecular solutes in the fixed-cavity approximation up to arbitrary order and with arbitrary perturbation operators. For electric dipole perturbations, pole and residue analyses of the response functions naturally lead to the identification of excitation energies and transition moments. We document the implementation of this approach in the Dalton program package using a recently developed open-ended response code and the PCMSolver libraries and present results for one-, two-, three-, four- and five-photon absorption processes of three small molecules in solution.

  3. A Self-consistent Model of the Coronal Heating and Solar Wind Acceleration Including Compressible and Incompressible Heating Processes

    Science.gov (United States)

    Shoda, Munehito; Yokoyama, Takaaki; Suzuki, Takeru K.

    2018-02-01

    We propose a novel one-dimensional model that includes both shock and turbulence heating and qualify how these processes contribute to heating the corona and driving the solar wind. Compressible MHD simulations allow us to automatically consider shock formation and dissipation, while turbulent dissipation is modeled via a one-point closure based on Alfvén wave turbulence. Numerical simulations were conducted with different photospheric perpendicular correlation lengths {λ }0, which is a critical parameter of Alfvén wave turbulence, and different root-mean-square photospheric transverse-wave amplitudes δ {v}0. For the various {λ }0, we obtain a low-temperature chromosphere, high-temperature corona, and supersonic solar wind. Our analysis shows that turbulence heating is always dominant when {λ }0≲ 1 {Mm}. This result does not mean that we can ignore the compressibility because the analysis indicates that the compressible waves and their associated density fluctuations enhance the Alfvén wave reflection and therefore the turbulence heating. The density fluctuation and the cross-helicity are strongly affected by {λ }0, while the coronal temperature and mass-loss rate depend weakly on {λ }0.

  4. Low temperature thermoelastic properties of galena in a simple, self-consistent, two-term Debye model

    Science.gov (United States)

    Knight, Kevin S.

    2015-03-01

    The thermoelastic properties of the thermoelectric chalcogenide galena, lead sulfide (PbS), have been determined in the temperature interval 10-350 K from high resolution neutron powder diffraction data, and literature values of the isobaric heat capacity. Within this temperature range, galena can be described by a simple phenomenological model in which the cation and anion vibrate independently of one another in a Debye-like manner, with vibrational Debye temperatures of 120(1) K for the lead, and 324(2) K for the sulfur. Simultaneous fitting of the unit cell volume and the isochoric heat capacity to a two-term Debye internal energy function gives characteristic temperatures of 110(2), and 326(5) K in excellent agreement with the measured vibrational Debye temperatures derived from fitting the atomic displacement parameters. The thermodynamic Grüneisen constant derived from the isochoric heat capacity is found to monotonically increase with decreasing temperature, from 2.5 at 300 K, to 3.25 at 25 K, in agreement with the deductions of earlier work. The full phonon density of states calculated from the two-term Debye model shows fair agreement with that derived from density functional theory.

  5. The Functional Segregation and Integration Model: Mixture Model Representations of Consistent and Variable Group-Level Connectivity in fMRI

    DEFF Research Database (Denmark)

    Churchill, Nathan William; Madsen, Kristoffer Hougaard; Mørup, Morten

    2016-01-01

    flexibility: they only estimate segregated structure and do not model interregional functional connectivity, nor do they account for network variability across voxels or between subjects. To address these issues, this letter develops the functional segregation and integration model (FSIM). This extension...... of the GMM framework simultaneously estimates spatial clustering and the most consistent group functional connectivity structure. It also explicitly models network variability, based on voxel- and subject-specific network scaling profiles. We compared the FSIM to standard GMM in a predictive cross......-validation framework and examined the importance of different model parameters, using both simulated and experimental resting-state data. The reliability of parcellations is not significantly altered by flexibility of the FSIM, whereas voxel- and subject-specific network scaling profiles significantly improve...

  6. Techniques for managing behaviour in pediatric dentistry: comparative study of live modelling and tell-show-do based on children's heart rates during treatment.

    Science.gov (United States)

    Farhat-McHayleh, Nada; Harfouche, Alice; Souaid, Philippe

    2009-05-01

    Tell-show-do is the most popular technique for managing children"s behaviour in dentists" offices. Live modelling is used less frequently, despite the satisfactory results obtained in studies conducted during the 1980s. The purpose of this study was to compare the effects of these 2 techniques on children"s heart rates during dental treatments, heart rate being the simplest biological parameter to measure and an increase in heart rate being the most common physiologic indicator of anxiety and fear. For this randomized, controlled, parallel-group single-centre clinical trial, children 5 to 9 years of age presenting for the first time to the Saint Joseph University dental care centre in Beirut, Lebanon, were divided into 3 groups: those in groups A and B were prepared for dental treatment by means of live modelling, the mother serving as the model for children in group A and the father as the model for children in group B. The children in group C were prepared by a pediatric dentist using the tell-show-do method. Each child"s heart rate was monitored during treatment, which consisted of an oral examination and cleaning. A total of 155 children met the study criteria and participated in the study. Children who received live modelling with the mother as model had lower heart rates than those who received live modelling with the father as model and those who were prepared by the tell-show-do method (p pediatric dentistry.

  7. On consistent definitions of momentum and energy fluxes for molecular dynamics models with multi-body interatomic potentials

    Science.gov (United States)

    Wu, Xiaojie; Li, Xiantao

    2015-01-01

    Results from molecular dynamics simulations often need to be further processed to understand the physics on a larger scale. This paper considers the definitions of momentum and energy fluxes obtained from a control-volume approach. To assess the validity of these defined quantities, two consistency criteria are proposed. As examples, the embedded atom potential and the Tersoff potential are considered. The consistency is verified using analytical and numerical methods.

  8. Plot showing ATLAS limits on Standard Model Higgs production in the mass range 110-150 GeV

    CERN Multimedia

    ATLAS Collaboration

    2011-01-01

    The combined upper limit on the Standard Model Higgs boson production cross section divided by the Standard Model expectation as a function of mH is indicated by the solid line. This is a 95% CL limit using the CLs method in in the low mass range. The dotted line shows the median expected limit in the absence of a signal and the green and yellow bands reflect the corresponding 68% and 95% expected

  9. Plot showing ATLAS limits on Standard Model Higgs production in the mass range 100-600 GeV

    CERN Multimedia

    ATLAS Collaboration

    2011-01-01

    The combined upper limit on the Standard Model Higgs boson production cross section divided by the Standard Model expectation as a function of mH is indicated by the solid line. This is a 95% CL limit using the CLs method in the entire mass range. The dotted line shows the median expected limit in the absence of a signal and the green and yellow bands reflect the corresponding 68% and 95% expected

  10. Consistent Pricing of VIX and Equity Derivatives with the 4/2 Stochastic Volatility Plus Jumps Model

    OpenAIRE

    Lin, Wei; Li, Shenghong; Luo, Xingguo; Chern, Shane

    2015-01-01

    In this paper, we develop a 4/2 stochastic volatility plus jumps model, namely, a new stochastic volatility model including the Heston model and 3/2 model as special cases. Our model is highly tractable by applying the Lie symmetries theory for PDEs, which means that the pricing procedure can be performed efficiently. In fact, we obtain a closed-form solution for the joint Fourier-Laplace transform so that equity and realized-variance derivatives can be priced. We also employ our model to con...

  11. Shingle 2.0 : Generalising self-consistent and automated domain discretisation for multi-scale geophysical models

    NARCIS (Netherlands)

    Candy, A.S.; Pietrzak, J.D.

    2018-01-01

    The approaches taken to describe and develop spatial discretisations of the domains required for geophysical simulation models are commonly ad hoc, model- or application-specific, and under-documented. This is particularly acute for simulation models that are flexible in their use of multi-scale,

  12. Metallic Material Image Segmentation by using 3D Grain Structure Consistency and Intra/Inter-Grain Model Information

    Science.gov (United States)

    2015-01-05

    fully-automatic method to detect cracks from pavement images, that can be used for pavement road maintenance. The developed method consists of three...steps: 1) A geodesic shadow-removal algorithm to remove the pavement shadows while preserving the cracks ; 2) building a crack probability map to enhance... cracks . Cracktree was evaluated on real pavement images and it achieves better performance than existing methods. 1 Multi-label Segmentation Propagation

  13. Consistent framework data for modeling and formation of scenarios in the Federal Environment Office; Konsistente Rahmendaten fuer Modellierungen und Szenariobildung im Umweltbundesamt

    Energy Technology Data Exchange (ETDEWEB)

    Weimer-Jehle, Wolfgang; Wassermann, Sandra; Kosow, Hannah [Internationales Zentrum fuer Kultur- und Technikforschung an der Univ. Stuttgart (Germany). ZIRN Interdisziplinaerer Forschungsschwerpunkt Risiko und Nachhaltige Technikentwicklung

    2011-04-15

    Model-based environmental scenarios normally require multiple framework assumptions regarding future social, political and economic developments (external developments). In most cases these framework assumptions are highly uncertain. Furthermore, different external developments are not isolated from each other and their interdependences can be described by qualitative judgments only. If the internal consistency of framework assumptions is not methodologically addressed, environmental models risk to be based on inconsistent combinations of framework assumptions which do not reflect existing relations between the respective factors in an appropriate way. This report aims at demonstrating how consistent context scenarios can be developed with the help of the cross-impact balance analysis (CIB). This method allows not only for the internal consistency of framework assumptions of a single model but also for the overall consistency of framework assumptions of modeling instruments, supporting the integrated interpretation of the results of different models. In order to demonstrate the method, in a first step, ten common framework assumptions were chosen and their possible future developments until 2030 were described. In a second step, a qualitative impact network was developed based on expert elicitation. The impact network provided the basis for a qualitative but systematic analysis of the internal consistency of combinations of framework assumptions. This analysis was carried out with the CIB-method and resulted in a set of consistent context scenarios. These scenarios can be used as an informative background for defining framework assumptions for environmental models at the UBA. (orig.)

  14. Three-dimensional modelling of soil-plant interactions : consistent coupling of soil and plant root systems

    OpenAIRE

    Schröder, Tom

    2009-01-01

    To understand how the uptake of water by roots locally affects and is affected by the soil water distribution, 3D soil-root water transfer models are needed. Nowadays, fully coupled 3D models at the plant scale, that simulate water flow along water potential gradients in the soil-root continuum, are available. However, the coupling of the soil and root system is not investigated thoroughly. In the available models the soil water potential gradient below the soil spatial discretization is negl...

  15. An improved algorithm for the polycrystal viscoplastic self-consistent model and its integration with implicit finite element schemes

    International Nuclear Information System (INIS)

    Galán, J; Verleysen, P; Lebensohn, R A

    2014-01-01

    A new algorithm for the solution of the deformation of a polycrystalline material using a self-consistent scheme, and its integration as part of the finite element software Abaqus/Standard are presented. The method is based on the original VPSC formulation by Lebensohn and Tomé and its integration with Abaqus/Standard by Segurado et al. The new algorithm has been implemented as a set of Fortran 90 modules, to be used either from a standalone program or from Abaqus subroutines. The new implementation yields the same results as VPSC7, but with a significantly better performance, especially when used in multicore computers. (paper)

  16. Characterisation of poly(lactic acid): poly(ethyleneoxide) (PLA:PEG) nanoparticles using the self-consistent theory modelling approach

    NARCIS (Netherlands)

    Heald, C.R.; Stolnik, S.; Matteis, De C.; Garnett, M.C.; Illum, L.; Davis, S.S.; Leermakers, F.A.M.

    2003-01-01

    Self-consistent field (SCF) modelling studies can be used to predict the properties of poly(lactic acid):poly(ethyleneoxide) (PLA:PEG) nanoparticles using the theory developed by Scheutjens and Fleer. Good agreement in the results between experimental and modelled data has been observed previously

  17. A consistent geochemical modelling approach for the leaching and reactive transport of major and trace elements in MSWI bottom ash

    NARCIS (Netherlands)

    Dijkstra, J.J.; Meeussen, J.C.L.; Sloot, van der H.A.; Comans, R.N.J.

    2008-01-01

    To improve the long-term environmental risk assessment of waste applications, a predictive "multi-surface" modelling approach has been developed to simultaneously predict the leaching and reactive transport of a broad range of major and trace elements (i.e., pH, Na, Al, Fe, Ca, SO4, Mg, Si, PO4,

  18. Skeletal Muscle Differentiation on a Chip Shows Human Donor Mesoangioblasts' Efficiency in Restoring Dystrophin in a Duchenne Muscular Dystrophy Model.

    Science.gov (United States)

    Serena, Elena; Zatti, Susi; Zoso, Alice; Lo Verso, Francesca; Tedesco, F Saverio; Cossu, Giulio; Elvassore, Nicola

    2016-12-01

    : Restoration of the protein dystrophin on muscle membrane is the goal of many research lines aimed at curing Duchenne muscular dystrophy (DMD). Results of ongoing preclinical and clinical trials suggest that partial restoration of dystrophin might be sufficient to significantly reduce muscle damage. Different myogenic progenitors are candidates for cell therapy of muscular dystrophies, but only satellite cells and pericytes have already entered clinical experimentation. This study aimed to provide in vitro quantitative evidence of the ability of mesoangioblasts to restore dystrophin, in terms of protein accumulation and distribution, within myotubes derived from DMD patients, using a microengineered model. We designed an ad hoc experimental strategy to miniaturize on a chip the standard process of muscle regeneration independent of variables such as inflammation and fibrosis. It is based on the coculture, at different ratios, of human dystrophin-positive myogenic progenitors and dystrophin-negative myoblasts in a substrate with muscle-like physiological stiffness and cell micropatterns. Results showed that both healthy myoblasts and mesoangioblasts restored dystrophin expression in DMD myotubes. However, mesoangioblasts showed unexpected efficiency with respect to myoblasts in dystrophin production in terms of the amount of protein produced (40% vs. 15%) and length of the dystrophin membrane domain (210-240 µm vs. 40-70 µm). These results show that our microscaled in vitro model of human DMD skeletal muscle validated previous in vivo preclinical work and may be used to predict efficacy of new methods aimed at enhancing dystrophin accumulation and distribution before they are tested in vivo, reducing time, costs, and variability of clinical experimentation. This study aimed to provide in vitro quantitative evidence of the ability of human mesoangioblasts to restore dystrophin, in terms of protein accumulation and distribution, within myotubes derived from

  19. Skeletal Muscle Differentiation on a Chip Shows Human Donor Mesoangioblasts’ Efficiency in Restoring Dystrophin in a Duchenne Muscular Dystrophy Model

    Science.gov (United States)

    Serena, Elena; Zatti, Susi; Zoso, Alice; Lo Verso, Francesca; Tedesco, F. Saverio; Cossu, Giulio

    2016-01-01

    Restoration of the protein dystrophin on muscle membrane is the goal of many research lines aimed at curing Duchenne muscular dystrophy (DMD). Results of ongoing preclinical and clinical trials suggest that partial restoration of dystrophin might be sufficient to significantly reduce muscle damage. Different myogenic progenitors are candidates for cell therapy of muscular dystrophies, but only satellite cells and pericytes have already entered clinical experimentation. This study aimed to provide in vitro quantitative evidence of the ability of mesoangioblasts to restore dystrophin, in terms of protein accumulation and distribution, within myotubes derived from DMD patients, using a microengineered model. We designed an ad hoc experimental strategy to miniaturize on a chip the standard process of muscle regeneration independent of variables such as inflammation and fibrosis. It is based on the coculture, at different ratios, of human dystrophin-positive myogenic progenitors and dystrophin-negative myoblasts in a substrate with muscle-like physiological stiffness and cell micropatterns. Results showed that both healthy myoblasts and mesoangioblasts restored dystrophin expression in DMD myotubes. However, mesoangioblasts showed unexpected efficiency with respect to myoblasts in dystrophin production in terms of the amount of protein produced (40% vs. 15%) and length of the dystrophin membrane domain (210–240 µm vs. 40–70 µm). These results show that our microscaled in vitro model of human DMD skeletal muscle validated previous in vivo preclinical work and may be used to predict efficacy of new methods aimed at enhancing dystrophin accumulation and distribution before they are tested in vivo, reducing time, costs, and variability of clinical experimentation. Significance This study aimed to provide in vitro quantitative evidence of the ability of human mesoangioblasts to restore dystrophin, in terms of protein accumulation and distribution, within myotubes

  20. Consistent Safety and Infectivity in Sporozoite Challenge Model of Plasmodium vivax in Malaria-Naive Human Volunteers

    Science.gov (United States)

    2011-02-01

    human volunteers with sporozoites. 6 A sporozoite challenge model has been available for P. falciparum for several decades and has led to...the reproduc- ibility of the infection. In those studies, sporozoites inoculated by < 5 mosquitoes led to an irregular infection in malaria-naive...particularly to Juana Vergara and Johanna Parra, for the vol- unteers’ recruitment and health assistance. We also thank Luz Amparo Martínez and all the

  1. No consistent bioenergetic defects in presynaptic nerve terminals isolated from mouse models of Alzheimer’s disease

    OpenAIRE

    Choi, Sung W.; Gerencser, Akos A.; Ng, Ryan; Flynn, James M.; Melov, Simon; Danielson, Steven R.; Gibson, Bradford W.; Nicholls, David G.; Bredesen, Dale E.; Brand, Martin D.

    2012-01-01

    Depressed cortical energy supply and impaired synaptic function are predominant associations of Alzheimer’s disease (AD). To test the hypothesis that presynaptic bioenergetic deficits are associated with the progression of AD pathogenesis, we compared bioenergetic variables of cortical and hippocampal presynaptic nerve terminals (synaptosomes) from commonly used mouse models with AD-like phenotypes (J20 age 6 months, Tg2576 age 16 months and APP/PS age 9 and 14 months) to ag...

  2. Modal Bin Hybrid Model: A surface area consistent, triple-moment sectional method for use in process-oriented modeling of atmospheric aerosols

    Science.gov (United States)

    Kajino, Mizuo; Easter, Richard C.; Ghan, Steven J.

    2013-09-01

    triple-moment sectional (TMS) aerosol dynamics model, Modal Bin Hybrid Model (MBHM), has been developed. In addition to number and mass (volume), surface area is predicted (and preserved), which is important for aerosol processes and properties such as gas-to-particle mass transfer, heterogeneous reaction, and light extinction cross section. The performance of MBHM was evaluated against double-moment sectional (DMS) models with coarse (BIN4) to very fine (BIN256) size resolutions for simulating evolution of particles under simultaneously occurring nucleation, condensation, and coagulation processes (BINx resolution uses x sections to cover the 1 nm to 1 µm size range). Because MBHM gives a physically consistent form of the intrasectional distributions, errors and biases of MBHM at BIN4-8 resolution were almost equivalent to those of DMS at BIN16-32 resolution for various important variables such as the moments Mk (k: 0, 2, 3), dMk/dt, and the number and volume of particles larger than a certain diameter. Another important feature of MBHM is that only a single bin is adequate to simulate full aerosol dynamics for particles whose size distribution can be approximated by a single lognormal mode. This flexibility is useful for process-oriented (multicategory and/or mixing state) modeling: Primary aerosols whose size parameters would not differ substantially in time and space can be expressed by a single or a small number of modes, whereas secondary aerosols whose size changes drastically from 1 to several hundred nanometers can be expressed by a number of modes. Added dimensions can be applied to MBHM to represent mixing state or photochemical age for aerosol mixing state studies.

  3. An NDVI-Based Vegetation Phenology Is Improved to be More Consistent with Photosynthesis Dynamics through Applying a Light Use Efficiency Model over Boreal High-Latitude Forests

    Directory of Open Access Journals (Sweden)

    Siheng Wang

    2017-07-01

    Full Text Available Remote sensing of high-latitude forests phenology is essential for understanding the global carbon cycle and the response of vegetation to climate change. The normalized difference vegetation index (NDVI has long been used to study boreal evergreen needleleaf forests (ENF and deciduous broadleaf forests. However, the NDVI-based growing season is generally reported to be longer than that based on gross primary production (GPP, which can be attributed to the difference between greenness and photosynthesis. Instead of introducing environmental factors such as land surface or air temperature like previous studies, this study attempts to make VI-based phenology more consistent with photosynthesis dynamics through applying a light use efficiency model. NDVI (MOD13C2 was used as a proxy for both fractional of absorbed photosynthetically active radiation (APAR and light use efficiency at seasonal time scale. Results show that VI-based phenology is improved towards tracking seasonal GPP changes more precisely after applying the light use efficiency model compared to raw NDVI or APAR, especially over ENF.

  4. Plectasin shows intracellular activity against Staphylococcus aureus in human THP-1 monocytes and in a mouse peritonitis model

    DEFF Research Database (Denmark)

    Brinch, Karoline Sidelmann; Sandberg, Anne; Baudoux, Pierre

    2009-01-01

    Antimicrobial therapy of infections with Staphylococcus aureus can pose a challenge due to slow response to therapy and recurrence of infection. These treatment difficulties can partly be explained by intracellular survival of staphylococci, which is why the intracellular activity...... was maintained (maximal relative efficacy [E(max)], 1.0- to 1.3-log reduction in CFU) even though efficacy was inferior to that of extracellular killing (E(max), >4.5-log CFU reduction). Animal studies included a novel use of the mouse peritonitis model, exploiting extra- and intracellular differentiation assays...... concentration. These findings stress the importance of performing studies of extra- and intracellular activity since these features cannot be predicted from traditional MIC and killing kinetic studies. Application of both the THP-1 and the mouse peritonitis models showed that the in vitro results were similar...

  5. Climate Modelling Shows Increased Risk to Eucalyptus sideroxylon on the Eastern Coast of Australia Compared to Eucalyptus albens.

    Science.gov (United States)

    Shabani, Farzin; Kumar, Lalit; Ahmadi, Mohsen

    2017-11-24

    Aim: To identify the extent and direction of range shift of Eucalyptus sideroxylon and E. albens in Australia by 2050 through an ensemble forecast of four species distribution models (SDMs). Each was generated using four global climate models (GCMs), under two representative concentration pathways (RCPs). Location: Australia. Methods : We used four SDMs of (i) generalized linear model, (ii) MaxEnt, (iii) random forest, and (iv) boosted regression tree to construct SDMs for species E. sideroxylon and E. albens under four GCMs including (a) MRI-CGCM3, (b) MIROC5, (c) HadGEM2-AO and (d) CCSM4, under two RCPs of 4.5 and 6.0. Here, the true skill statistic (TSS) index was used to assess the accuracy of each SDM. Results: Results showed that E. albens and E. sideroxylon will lose large areas of their current suitable range by 2050 and E. sideroxylon is projected to gain in eastern and southeastern Australia. Some areas were also projected to remain suitable for each species between now and 2050. Our modelling showed that E. sideroxylon will lose suitable habitat on the western side and will not gain any on the eastern side because this region is one the most heavily populated areas in the country, and the populated areas are moving westward. The predicted decrease in E. sideroxylon's distribution suggests that land managers should monitor its population closely, and evaluate whether it meets criteria for a protected legal status. Main conclusions: Both Eucalyptus sideroxylon and E. albens will be negatively affected by climate change and it is projected that E. sideroxylon will be at greater risk of losing habitat than E. albens .

  6. Climate Modelling Shows Increased Risk to Eucalyptus sideroxylon on the Eastern Coast of Australia Compared to Eucalyptus albens

    Directory of Open Access Journals (Sweden)

    Farzin Shabani

    2017-11-01

    Full Text Available Aim: To identify the extent and direction of range shift of Eucalyptus sideroxylon and E. albens in Australia by 2050 through an ensemble forecast of four species distribution models (SDMs. Each was generated using four global climate models (GCMs, under two representative concentration pathways (RCPs. Location: Australia. Methods: We used four SDMs of (i generalized linear model, (ii MaxEnt, (iii random forest, and (iv boosted regression tree to construct SDMs for species E. sideroxylon and E. albens under four GCMs including (a MRI-CGCM3, (b MIROC5, (c HadGEM2-AO and (d CCSM4, under two RCPs of 4.5 and 6.0. Here, the true skill statistic (TSS index was used to assess the accuracy of each SDM. Results: Results showed that E. albens and E. sideroxylon will lose large areas of their current suitable range by 2050 and E. sideroxylon is projected to gain in eastern and southeastern Australia. Some areas were also projected to remain suitable for each species between now and 2050. Our modelling showed that E. sideroxylon will lose suitable habitat on the western side and will not gain any on the eastern side because this region is one the most heavily populated areas in the country, and the populated areas are moving westward. The predicted decrease in E. sideroxylon’s distribution suggests that land managers should monitor its population closely, and evaluate whether it meets criteria for a protected legal status. Main conclusions: Both Eucalyptus sideroxylon and E. albens will be negatively affected by climate change and it is projected that E. sideroxylon will be at greater risk of losing habitat than E. albens.

  7. Coadministration of doxorubicin and etoposide loaded in camel milk phospholipids liposomes showed increased antitumor activity in a murine model

    Directory of Open Access Journals (Sweden)

    Maswadeh HM

    2015-04-01

    Full Text Available Hamzah M Maswadeh,1 Ahmed N Aljarbou,1 Mohammed S Alorainy,2 Arshad H Rahmani,3 Masood A Khan3 1Department of Pharmaceutics, College of Pharmacy, 2Department of Pharmacology and Therapeutics, College of Medicine, 3College of Applied Medical Sciences, Qassim University, Buraydah, Kingdom of Saudi Arabia Abstract: Small unilamellar vesicles from camel milk phospholipids (CML mixture or from 1,2 dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC were prepared, and anticancer drugs doxorubicin (Dox or etoposide (ETP were loaded. Liposomal formulations were used against fibrosarcoma in a murine model. Results showed a very high percentage of Dox encapsulation (~98% in liposomes (Lip prepared from CML-Lip or DPPC-Lip, whereas the percentage of encapsulations of ETP was on the lower side, 22% of CML-Lip and 18% for DPPC-Lip. Differential scanning calorimetry curves show that Dox enhances the lamellar formation in CML-Lip, whereas ETP enhances the nonlamellar formation. Differential scanning calorimetry curves also showed that the presence of Dox and ETP together into DPPC-Lip produced the interdigitation effect. The in vivo anticancer activity of liposomal formulations of Dox or ETP or a combination of both was assessed against benzopyrene (BAP-induced fibrosarcoma in a murine model. Tumor-bearing mice treated with a combination of Dox and ETP loaded into CML-Lip showed increased survival and reduced tumor growth compared to other groups, including the combination of Dox and ETP in DPPC-Lip. Fibrosarcoma-bearing mice treated with a combination of free (Dox + ETP showed much higher tumor growth compared to those groups treated with CML-Lip-(Dox + ETP or DPPC-Lip-(Dox + ETP. Immunohistochemical study was also performed to show the expression of tumor-suppressor PTEN, and it was found that the tumor tissues from the group of mice treated with a combination of free (Dox + ETP showed greater loss of cytoplasmic PTEN than tumor tissues obtained from the

  8. Connecting with The Biggest Loser: an extended model of parasocial interaction and identification in health-related reality TV shows.

    Science.gov (United States)

    Tian, Yan; Yoo, Jina H

    2015-01-01

    This study investigates audience responses to health-related reality TV shows in the setting of The Biggest Loser. It conceptualizes a model for audience members' parasocial interaction and identification with cast members and explores antecedents and outcomes of parasocial interaction and identification. Data analysis suggests the following direct relationships: (1) audience members' exposure to the show is positively associated with parasocial interaction, which in turn is positively associated with identification, (2) parasocial interaction is positively associated with exercise self-efficacy, whereas identification is negatively associated with exercise self-efficacy, and (3) exercise self-efficacy is positively associated with exercise behavior. Indirect effects of parasocial interaction and identification on exercise self-efficacy and exercise behavior are also significant. We discuss the theoretical and practical implications of these findings.

  9. Heuristic Analysis Model of Nitrided Layers’ Formation Consisting of the Image Processing and Analysis and Elements of Artificial Intelligence

    Science.gov (United States)

    Wójcicki, Tomasz; Nowicki, Michał

    2016-01-01

    The article presents a selected area of research and development concerning the methods of material analysis based on the automatic image recognition of the investigated metallographic sections. The objectives of the analyses of the materials for gas nitriding technology are described. The methods of the preparation of nitrided layers, the steps of the process and the construction and operation of devices for gas nitriding are given. We discuss the possibility of using the methods of digital images processing in the analysis of the materials, as well as their essential task groups: improving the quality of the images, segmentation, morphological transformations and image recognition. The developed analysis model of the nitrided layers formation, covering image processing and analysis techniques, as well as selected methods of artificial intelligence are presented. The model is divided into stages, which are formalized in order to better reproduce their actions. The validation of the presented method is performed. The advantages and limitations of the developed solution, as well as the possibilities of its practical use, are listed. PMID:28773389

  10. Heuristic Analysis Model of Nitrided Layers' Formation Consisting of the Image Processing and Analysis and Elements of Artificial Intelligence.

    Science.gov (United States)

    Wójcicki, Tomasz; Nowicki, Michał

    2016-04-01

    The article presents a selected area of research and development concerning the methods of material analysis based on the automatic image recognition of the investigated metallographic sections. The objectives of the analyses of the materials for gas nitriding technology are described. The methods of the preparation of nitrided layers, the steps of the process and the construction and operation of devices for gas nitriding are given. We discuss the possibility of using the methods of digital images processing in the analysis of the materials, as well as their essential task groups: improving the quality of the images, segmentation, morphological transformations and image recognition. The developed analysis model of the nitrided layers formation, covering image processing and analysis techniques, as well as selected methods of artificial intelligence are presented. The model is divided into stages, which are formalized in order to better reproduce their actions. The validation of the presented method is performed. The advantages and limitations of the developed solution, as well as the possibilities of its practical use, are listed.

  11. Geometrically Consistent Mesh Modification

    KAUST Repository

    Bonito, A.

    2010-01-01

    A new paradigm of adaptivity is to execute refinement, coarsening, and smoothing of meshes on manifolds with incomplete information about their geometry and yet preserve position and curvature accuracy. We refer to this collectively as geometrically consistent (GC) mesh modification. We discuss the concept of discrete GC, show the failure of naive approaches, and propose and analyze a simple algorithm that is GC and accuracy preserving. © 2010 Society for Industrial and Applied Mathematics.

  12. Predictors of consistent condom use based on the Information-Motivation-Behavior Skill (IMB) model among senior high school students in three coastal cities in China.

    Science.gov (United States)

    Cai, Yong; Ye, Xiuxia; Shi, Rong; Xu, Gang; Shen, Lixiao; Ren, Jia; Huang, Hong

    2013-06-04

    High prevalence of risky sexual behaviors and lack of information, skills and preventive support mean that, adolescents face high risks of HIV/AIDS. This study applied the information-motivation-behavioral skills (IMB) model to examine the predictors of consistent condom use among senior high school students from three coastal cities in China and clarify the relationships between the model constructs. A cross-sectional study was conducted to assess HIV/AIDS related information, motivation, behavioral skills and preventive behaviors among senior high school students in three coastal cities in China. Structural equation modelling (SEM) was used to assess the IMB model. Of the 12313 participants, 4.5% (95% CI: 4.2-5.0) reported having had premarital sex and among them 25.0% (95% CI: 21.2-29.1) reported having used a condom in their sexual debut. Only about one-ninth of participants reported consistent condom use. The final IMB model provided acceptable fit to the data (CFI = 0.981, RMSEA = 0.014). Consistent condom use was significantly predicted by motivation (β = 0.175, P students in China. The IMB model could predict consistent condom use and suggests that future interventions should focus on improving motivation and behavioral skills.

  13. The vortex-like self-consistent electron fluid model by the applied-B ion diode: equilibrium and instability

    International Nuclear Information System (INIS)

    Gordeev, A.V.

    1996-01-01

    The electron inertia effects in the one-dimensional model of the applied-B ion diode for the relativistic diode potential eU/m e c 2 ≥ 1 were investigated, where the magnetic Debye length r B is of the order of the collisionless electron skin depth c/ω pe . For this, an analytical relation between the magnetic field and the electric potential was developed, owing to which the second order eigenvalue problem can be reduced to a system of algebraic equations. Instabilities inside the vacuum gap and in the near-anode emitting plasma are considered. In the near-anode Hall plasma, the instability with two ion species was obtained; this can can contribute to the ion angle divergence. (author). 10 refs

  14. A Spectral Unmixing Model for the Integration of Multi-Sensor Imagery: A Tool to Generate Consistent Time Series Data

    Directory of Open Access Journals (Sweden)

    Georgia Doxani

    2015-10-01

    Full Text Available The Sentinel missions have been designed to support the operational services of the Copernicus program, ensuring long-term availability of data for a wide range of spectral, spatial and temporal resolutions. In particular, Sentinel-2 (S-2 data with improved high spatial resolution and higher revisit frequency (five days with the pair of satellites in operation will play a fundamental role in recording land cover types and monitoring land cover changes at regular intervals. Nevertheless, cloud coverage usually hinders the time series availability and consequently the continuous land surface monitoring. In an attempt to alleviate this limitation, the synergistic use of instruments with different features is investigated, aiming at the future synergy of the S-2 MultiSpectral Instrument (MSI and Sentinel-3 (S-3 Ocean and Land Colour Instrument (OLCI. To that end, an unmixing model is proposed with the intention of integrating the benefits of the two Sentinel missions, when both in orbit, in one composite image. The main goal is to fill the data gaps in the S-2 record, based on the more frequent information of the S-3 time series. The proposed fusion model has been applied on MODIS (MOD09GA L2G and SPOT4 (Take 5 data and the experimental results have demonstrated that the approach has high potential. However, the different acquisition characteristics of the sensors, i.e. illumination and viewing geometry, should be taken into consideration and bidirectional effects correction has to be performed in order to reduce noise in the reflectance time series.

  15. Restless led syndrome model Drosophila melanogaster show successful olfactory learning and 1-day retention of the acquired memory

    Directory of Open Access Journals (Sweden)

    Mika F. Asaba

    2013-09-01

    Full Text Available Restless Legs Syndrome (RLS is a prevalent but poorly understood disorder that ischaracterized by uncontrollable movements during sleep, resulting in sleep disturbance.Olfactory memory in Drosophila melanogaster has proven to be a useful tool for the study ofcognitive deficits caused by sleep disturbances, such as those seen in RLS. A recently generatedDrosophila model of RLS exhibited disturbed sleep patterns similar to those seen in humans withRLS. This research seeks to improve understanding of the relationship between cognitivefunctioning and sleep disturbances in a new model for RLS. Here, we tested learning andmemory in wild type and dBTBD9 mutant flies by Pavlovian olfactory conditioning, duringwhich a shock was paired with one of two odors. Flies were then placed in a T-maze with oneodor on either side, and successful associative learning was recorded when the flies chose theside with the unpaired odor. We hypothesized that due to disrupted sleep patterns, dBTBD9mutant flies would be unable to learn the shock-odor association. However, the current studyreports that the recently generated Drosophila model of RLS shows successful olfactorylearning, despite disturbed sleep patterns, with learning performance levels matching or betterthan wild type flies.

  16. Final theory spiral-field-model. Basic ideas for a compatible physics and a consistent nature science

    International Nuclear Information System (INIS)

    Hartje, U.A.J.

    2005-01-01

    This script contains theses for an universal 'Spiral-Field-Theory' that are capable to dissolve problems in parallel from different areas which are far from each other. Starting point is the stuck principle discussion about the relationships between the Classic Physics and the Quantum Physics. Aim is the clarification of questions which remained open. In 1925 Max Planck had formulated as follows: 'The research of physics can not rest, so long not has been together-welded: on the one hand the mechanics and the electrodynamics with on the other hand the lesson of the stationary one and the radiating heat to a sole unitary theory'. The Spiral-Field-Model develops a supporting structure from General Field into which they will class the secure knowledge from experiments and well-proved theories. The most important thing of this new Final Theory is the detailed generating of all nature courses of phenomena exclusively from radiation and that in the direct meaning of the word. In the final effect the two great disciplines of the physics which are drifted from each other, become bonded together to a super ordinate theoretical building of the nature sciences. (orig.)

  17. Eye Movement Deficits Are Consistent with a Staging Model of pTDP-43 Pathology in Amyotrophic Lateral Sclerosis.

    Directory of Open Access Journals (Sweden)

    Martin Gorges

    Full Text Available The neuropathological process underlying amyotrophic lateral sclerosis (ALS can be traced as a four-stage progression scheme of sequential corticofugal axonal spread. The examination of eye movement control gains deep insights into brain network pathology and provides the opportunity to detect both disturbance of the brainstem oculomotor circuitry as well as executive deficits of oculomotor function associated with higher brain networks.To study systematically oculomotor characteristics in ALS and its underlying network pathology in order to determine whether eye movement deterioration can be categorized within a staging system of oculomotor decline that corresponds to the neuropathological model.Sixty-eight ALS patients and 31 controls underwent video-oculographic, clinical and neuropsychological assessments.Oculomotor examinations revealed increased anti- and delayed saccades' errors, gaze-palsy and a cerebellary type of smooth pursuit disturbance. The oculomotor disturbances occurred in a sequential manner: Stage 1, only executive control of eye movements was affected. Stage 2 indicates disturbed executive control plus 'genuine' oculomotor dysfunctions such as gaze-paly. We found high correlations (p<0.001 between the oculomotor stages and both, the clinical presentation as assessed by the ALS Functional Rating Scale (ALSFRS score, and cognitive scores from the Edinburgh Cognitive and Behavioral ALS Screen (ECAS.Dysfunction of eye movement control in ALS can be characterized by a two-staged sequential pattern comprising executive deficits in Stage 1 and additional impaired infratentorial oculomotor control pathways in Stage 2. This pattern parallels the neuropathological staging of ALS and may serve as a technical marker of the neuropathological spreading.

  18. Funding Medical Research Projects: Taking into Account Referees' Severity and Consistency through Many-Faceted Rasch Modeling of Projects' Scores.

    Science.gov (United States)

    Tesio, Luigi; Simone, Anna; Grzeda, Mariuzs T; Ponzio, Michela; Dati, Gabriele; Zaratin, Paola; Perucca, Laura; Battaglia, Mario A

    2015-01-01

    The funding policy of research projects often relies on scores assigned by a panel of experts (referees). The non-linear nature of raw scores and the severity and inconsistency of individual raters may generate unfair numeric project rankings. Rasch measurement (many-facets version, MFRM) provides a valid alternative to scoring. MFRM was applied to the scores achieved by 75 research projects on multiple sclerosis sent in response to a previous annual call by FISM-Italian Foundation for Multiple Sclerosis. This allowed to simulate, a posteriori, the impact of MFRM on the funding scenario. The applications were each scored by 2 to 4 independent referees (total = 131) on a 10-item, 0-3 rating scale called FISM-ProQual-P. The rotation plan assured "connection" of all pairs of projects through at least 1 shared referee.The questionnaire fulfilled satisfactorily the stringent criteria of Rasch measurement for psychometric quality (unidimensionality, reliability and data-model fit). Arbitrarily, 2 acceptability thresholds were set at a raw score of 21/30 and at the equivalent Rasch measure of 61.5/100, respectively. When the cut-off was switched from score to measure 8 out of 18 acceptable projects had to be rejected, while 15 rejected projects became eligible for funding. Some referees, of various severity, were grossly inconsistent (z-std fit indexes less than -1.9 or greater than 1.9). The FISM-ProQual-P questionnaire seems a valid and reliable scale. MFRM may help the decision-making process for allocating funds to MS research projects but also in other fields. In repeated assessment exercises it can help the selection of reliable referees. Their severity can be steadily calibrated, thus obviating the need to connect them with other referees assessing the same projects.

  19. The BACHD Rat Model of Huntington Disease Shows Specific Deficits in a Test Battery of Motor Function

    Directory of Open Access Journals (Sweden)

    Giuseppe Manfré

    2017-11-01

    Full Text Available Rationale: Huntington disease (HD is a progressive neurodegenerative disorder characterized by motor, cognitive and neuropsychiatric symptoms. HD is usually diagnosed by the appearance of motor deficits, resulting in skilled hand use disruption, gait abnormality, muscle wasting and choreatic movements. The BACHD transgenic rat model for HD represents a well-established transgenic rodent model of HD, offering the prospect of an in-depth characterization of the motor phenotype.Objective: The present study aims to characterize different aspects of motor function in BACHD rats, combining classical paradigms with novel high-throughput behavioral phenotyping.Methods: Wild-type (WT and transgenic animals were tested longitudinally from 2 to 12 months of age. To measure fine motor control, rats were challenged with the pasta handling test and the pellet reaching test. To evaluate gross motor function, animals were assessed by using the holding bar and the grip strength tests. Spontaneous locomotor activity and circadian rhythmicity were assessed in an automated home-cage environment, namely the PhenoTyper. We then integrated existing classical methodologies to test motor function with automated home-cage assessment of motor performance.Results: BACHD rats showed strong impairment in muscle endurance at 2 months of age. Altered circadian rhythmicity and locomotor activity were observed in transgenic animals. On the other hand, reaching behavior, forepaw dexterity and muscle strength were unaffected.Conclusions: The BACHD rat model exhibits certain features of HD patients, like muscle weakness and changes in circadian behavior. We have observed modest but clear-cut deficits in distinct motor phenotypes, thus confirming the validity of this transgenic rat model for treatment and drug discovery purposes.

  20. Network models of TEM β-lactamase mutations coevolving under antibiotic selection show modular structure and anticipate evolutionary trajectories.

    Science.gov (United States)

    Guthrie, Violeta Beleva; Allen, Jennifer; Camps, Manel; Karchin, Rachel

    2011-09-01

    Understanding how novel functions evolve (genetic adaptation) is a critical goal of evolutionary biology. Among asexual organisms, genetic adaptation involves multiple mutations that frequently interact in a non-linear fashion (epistasis). Non-linear interactions pose a formidable challenge for the computational prediction of mutation effects. Here we use the recent evolution of β-lactamase under antibiotic selection as a model for genetic adaptation. We build a network of coevolving residues (possible functional interactions), in which nodes are mutant residue positions and links represent two positions found mutated together in the same sequence. Most often these pairs occur in the setting of more complex mutants. Focusing on extended-spectrum resistant sequences, we use network-theoretical tools to identify triple mutant trajectories of likely special significance for adaptation. We extrapolate evolutionary paths (n = 3) that increase resistance and that are longer than the units used to build the network (n = 2). These paths consist of a limited number of residue positions and are enriched for known triple mutant combinations that increase cefotaxime resistance. We find that the pairs of residues used to build the network frequently decrease resistance compared to their corresponding singlets. This is a surprising result, given that their coevolution suggests a selective advantage. Thus, β-lactamase adaptation is highly epistatic. Our method can identify triplets that increase resistance despite the underlying rugged fitness landscape and has the unique ability to make predictions by placing each mutant residue position in its functional context. Our approach requires only sequence information, sufficient genetic diversity, and discrete selective pressures. Thus, it can be used to analyze recent evolutionary events, where coevolution analysis methods that use phylogeny or statistical coupling are not possible. Improving our ability to assess

  1. Chemical composition analysis and product consistency tests to support enhanced Hanford waste glass models. Results for the third set of high alumina outer layer matrix glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-12-01

    In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for 14 simulated high level waste glasses fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions. The measured chemical composition data are reported and compared with the targeted values for each component for each glass. All of the measured sums of oxides for the study glasses fell within the interval of 96.9 to 100.8 wt %, indicating recovery of all components. Comparisons of the targeted and measured chemical compositions showed that the measured values for the glasses met the targeted concentrations within 10% for those components present at more than 5 wt %. The PCT results were normalized to both the targeted and measured compositions of the study glasses. Several of the glasses exhibited increases in normalized concentrations (NCi) after the canister centerline cooled (CCC) heat treatment. Five of the glasses, after the CCC heat treatment, had NCB values that exceeded that of the Environmental Assessment (EA) benchmark glass. These results can be combined with additional characterization, including X-ray diffraction, to determine the cause of the higher release rates.

  2. Nine time steps: ultra-fast statistical consistency testing of the Community Earth System Model (pyCECT v3.0)

    Science.gov (United States)

    Milroy, Daniel J.; Baker, Allison H.; Hammerling, Dorit M.; Jessup, Elizabeth R.

    2018-02-01

    The Community Earth System Model Ensemble Consistency Test (CESM-ECT) suite was developed as an alternative to requiring bitwise identical output for quality assurance. This objective test provides a statistical measurement of consistency between an accepted ensemble created by small initial temperature perturbations and a test set of CESM simulations. In this work, we extend the CESM-ECT suite with an inexpensive and robust test for ensemble consistency that is applied to Community Atmospheric Model (CAM) output after only nine model time steps. We demonstrate that adequate ensemble variability is achieved with instantaneous variable values at the ninth step, despite rapid perturbation growth and heterogeneous variable spread. We refer to this new test as the Ultra-Fast CAM Ensemble Consistency Test (UF-CAM-ECT) and demonstrate its effectiveness in practice, including its ability to detect small-scale events and its applicability to the Community Land Model (CLM). The new ultra-fast test facilitates CESM development, porting, and optimization efforts, particularly when used to complement information from the original CESM-ECT suite of tools.

  3. Show-Bix &

    DEFF Research Database (Denmark)

    2014-01-01

    The anti-reenactment 'Show-Bix &' consists of 5 dias projectors, a dial phone, quintophonic sound, and interactive elements. A responsive interface will enable the Dias projectors to show copies of original dias slides from the Show-Bix piece ”March på Stedet”, 265 images in total. The copies are...

  4. BO-1055, a novel DNA cross-linking agent with remarkable low myelotoxicity shows potent activity in sarcoma models.

    Science.gov (United States)

    Ambati, Srikanth R; Shieh, Jae-Hung; Pera, Benet; Lopes, Eloisi Caldas; Chaudhry, Anisha; Wong, Elissa W P; Saxena, Ashish; Su, Tsann-Long; Moore, Malcolm A S

    2016-07-12

    DNA damaging agents cause rapid shrinkage of tumors and form the basis of chemotherapy for sarcomas despite significant toxicities. Drugs having superior efficacy and wider therapeutic windows are needed to improve patient outcomes. We used cell proliferation and apoptosis assays in sarcoma cell lines and benign cells; γ-H2AX expression, comet assay, immunoblot analyses and drug combination studies in vitro and in patient derived xenograft (PDX) models. BO-1055 caused apoptosis and cell death in a concentration and time dependent manner in sarcoma cell lines. BO-1055 had potent activity (submicromolar IC50) against Ewing sarcoma and rhabdomyosarcoma, intermediate activity in DSRCT (IC50 = 2-3μM) and very weak activity in osteosarcoma (IC50 >10μM) cell lines. BO-1055 exhibited a wide therapeutic window compared to other DNA damaging drugs. BO-1055 induced more DNA double strand breaks and γH2AX expression in cancer cells compared to benign cells. BO-1055 showed inhibition of tumor growth in A673 xenografts and caused tumor regression in cyclophosphamide resistant patient-derived Ewing sarcoma xenografts and A204 xenografts. Combination of BO-1055 and irinotecan demonstrated synergism in Ewing sarcoma PDX models. Potent activity on sarcoma cells and its relative lack of toxicity presents a strong rationale for further development of BO-1055 as a therapeutic agent.

  5. Reporting consistently on CSR

    DEFF Research Database (Denmark)

    Thomsen, Christa; Nielsen, Anne Ellerup

    2006-01-01

    This chapter first outlines theory and literature on CSR and Stakeholder Relations focusing on the different perspectives and the contextual and dynamic character of the CSR concept. CSR reporting challenges are discussed and a model of analysis is proposed. Next, our paper presents the results...... in the reporting material. By implementing consistent discourse strategies that interact according to a well-defined pattern or order, it is possible to communicate a strong social commitment on the one hand, and to take into consideration the expectations of the shareholders and the other stakeholders...

  6. Demographical history and palaeodistribution modelling show range shift towards Amazon Basin for a Neotropical tree species in the LGM.

    Science.gov (United States)

    Vitorino, Luciana Cristina; Lima-Ribeiro, Matheus S; Terribile, Levi Carina; Collevatti, Rosane G

    2016-10-13

    We studied the phylogeography and demographical history of Tabebuia serratifolia (Bignoniaceae) to understand the disjunct geographical distribution of South American seasonally dry tropical forests (SDTFs). We specifically tested if the multiple and isolated patches of SDTFs are current climatic relicts of a widespread and continuously distributed dry forest during the last glacial maximum (LGM), the so called South American dry forest refugia hypothesis, using ecological niche modelling (ENM) and statistical phylogeography. We sampled 235 individuals of T. serratifolia in 17 populations in Brazil and analysed the polymorphisms at three intergenic chloroplast regions and ITS nuclear ribosomal DNA. Coalescent analyses showed a demographical expansion at the last c. 130 ka (thousand years before present). Simulations and ENM also showed that the current spatial pattern of genetic diversity is most likely due to a scenario of range expansion and range shift towards the Amazon Basin during the colder and arid climatic conditions associated with the LGM, matching the expected for the South American dry forest refugia hypothesis, although contrasting to the Pleistocene Arc hypothesis. Populations in more stable areas or with higher suitability through time showed higher genetic diversity. Postglacial range shift towards the Southeast and Atlantic coast may have led to spatial genome assortment due to leading edge colonization as the species tracks suitable environments, leading to lower genetic diversity in populations at higher distance from the distribution centroid at 21 ka. Haplotype sharing or common ancestry among populations from Caatinga in Northeast Brazil, Atlantic Forest in Southeast and Cerrado biome and ENM evince the past connection among these biomes.

  7. Plasma and BIAS Modeling: Self-Consistent Electrostatic Particle-in-Cell with Low-Density Argon Plasma for TiC

    Directory of Open Access Journals (Sweden)

    Jürgen Geiser

    2011-01-01

    processes. In this paper we present a new model taken into account a self-consistent electrostatic-particle in cell model with low density Argon plasma. The collision model are based of Monte Carlo simulations is discussed for DC sputtering in lower pressure regimes. In order to simulate transport phenomena within sputtering processes realistically, a spatial and temporal knowledge of the plasma density and electrostatic field configuration is needed. Due to relatively low plasma densities, continuum fluid equations are not applicable. We propose instead a Particle-in-cell (PIC method, which allows the study of plasma behavior by computing the trajectories of finite-size particles under the action of an external and self-consistent electric field defined in a grid of points.

  8. 1990 Volvo Award in clinical sciences. The consistency and accuracy of roentgenograms for measuring sagittal translation in the lumbar vertebral motion segment. An experimental model.

    Science.gov (United States)

    Shaffer, W O; Spratt, K F; Weinstein, J; Lehmann, T R; Goel, V

    1990-08-01

    An experimental model of the L4-L5 lumbar motion segment was developed that allowed precise manipulation of sagittal translation, rotation of L5 relative to L4, tilt of L4 on L5, and control of roentgenogram quality (image clarity) by placing a water bath between the tube and the vertebral body. A series of experiments were designed to systematically assess the consistency and accuracy of sagittal translation measurements from roentgenograms of varying quality, using different measurement protocols and various rater combinations on models with varying degrees of concomitant motions (rotations and tilts). Study 1 assessed the effects of roentgenogram quality, raters, and seven measurement methods on the consistency and accuracy of evaluating translations in the sagittal plane. Results indicated very high reliabilities across roentgenogram quality, raters, and measurement. As expected, high-quality roentgenograms were more accurately evaluated than lower-quality roentgenograms. However, closer inspection of the consequences of errors in measured translations indicated surprisingly high false-positive and false-negative rates, with significant differences observed between measurement methods. Study 2 assessed the effects of concomitant motions and measurement methods on the consistency and accuracy of evaluations. Within-rater consistency and accuracy indices were remarkably high and similar across measurement methods and degrees of concomitant motions. However, important differences in the false-positive and false-negative rates were again observed. Method 2, described by Morgan and King, demonstrated the overall best performance and the least interference due to concomitant motions. Study 3 assessed the effects of raters and measurement methods on the consistency of measuring translation in clinical roentgenograms, where concomitant motion factors may be present, but not explicitly considered. Results indicated substantially lower within- and between

  9. A new 2D climate model with chemistry and self consistent eddy-parameterization. The impact of airplane NO{sub x} on the chemistry of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Gepraegs, R.; Schmitz, G.; Peters, D. [Institut fuer Atmosphaerenphysik, Kuehlungsborn (Germany)

    1997-12-31

    A 2D version of the ECHAM T21 climate model has been developed. The new model includes an efficient spectral transport scheme with implicit diffusion. Furthermore, photodissociation and chemistry of the NCAR 2D model have been incorporated. A self consistent parametrization scheme is used for eddy heat- and momentum flux in the troposphere. It is based on the heat flux parametrization of Branscome and mixing-length formulation for quasi-geostrophic vorticity. Above 150 hPa the mixing-coefficient K{sub yy} is prescribed. Some of the model results are discussed, concerning especially the impact of aircraft NO{sub x} emission on the model chemistry. (author) 6 refs.

  10. Overview of the Special Issue: A Multi-Model Framework to Achieve Consistent Evaluation of Climate Change Impacts in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Waldhoff, Stephanie T.; Martinich, Jeremy; Sarofim, Marcus; DeAngelo, B. J.; McFarland, Jim; Jantarasami, Lesley; Shouse, Kate C.; Crimmins, Allison; Ohrel, Sara; Li, Jia

    2015-07-01

    The Climate Change Impacts and Risk Analysis (CIRA) modeling exercise is a unique contribution to the scientific literature on climate change impacts, economic damages, and risk analysis that brings together multiple, national-scale models of impacts and damages in an integrated and consistent fashion to estimate climate change impacts, damages, and the benefits of greenhouse gas (GHG) mitigation actions in the United States. The CIRA project uses three consistent socioeconomic, emissions, and climate scenarios across all models to estimate the benefits of GHG mitigation policies: a Business As Usual (BAU) and two policy scenarios with radiative forcing (RF) stabilization targets of 4.5 W/m2 and 3.7 W/m2 in 2100. CIRA was also designed to specifically examine the sensitivity of results to uncertainties around climate sensitivity and differences in model structure. The goals of CIRA project are to 1) build a multi-model framework to produce estimates of multiple risks and impacts in the U.S., 2) determine to what degree risks and damages across sectors may be lowered from a BAU to policy scenarios, 3) evaluate key sources of uncertainty along the causal chain, and 4) provide information for multiple audiences and clearly communicate the risks and damages of climate change and the potential benefits of mitigation. This paper describes the motivations, goals, and design of the CIRA modeling exercise and introduces the subsequent papers in this special issue.

  11. A new formulation of cannabidiol in cream shows therapeutic effects in a mouse model of experimental autoimmune encephalomyelitis.

    Science.gov (United States)

    Giacoppo, Sabrina; Galuppo, Maria; Pollastro, Federica; Grassi, Gianpaolo; Bramanti, Placido; Mazzon, Emanuela

    2015-10-21

    The present study was designed to investigate the efficacy of a new formulation of alone, purified cannabidiol (CBD) (>98 %), the main non-psychotropic cannabinoid of Cannabis sativa, as a topical treatment in an experimental model of autoimmune encephalomyelitis (EAE), the most commonly used model for multiple sclerosis (MS). Particularly, we evaluated whether administration of a topical 1 % CBD-cream, given at the time of symptomatic disease onset, could affect the EAE progression and if this treatment could also recover paralysis of hind limbs, qualifying topical-CBD for the symptomatic treatment of MS. In order to have a preparation of 1 % of CBD-cream, pure CBD have been solubilized in propylene glycoland basic dense cream O/A. EAE was induced by immunization with myelin oligodendroglial glycoprotein peptide (MOG35-55) in C57BL/6 mice. After EAE onset, mice were allocated into several experimental groups (Naïve, EAE, EAE-1 % CBD-cream, EAE-vehicle cream, CTRL-1 % CBD-cream, CTRL-vehicle cream). Mice were observed daily for signs of EAE and weight loss. At the sacrifice of the animals, which occurred at the 28(th) day from EAE-induction, spinal cord and spleen tissues were collected in order to perform histological evaluation, immunohistochemistry and western blotting analysis. Achieved results surprisingly show that daily treatment with topical 1 % CBD-cream may exert neuroprotective effects against EAE, diminishing clinical disease score (mean of 5.0 in EAE mice vs 1.5 in EAE + CBD-cream), by recovering of paralysis of hind limbs and by ameliorating histological score typical of disease (lymphocytic infiltration and demyelination) in spinal cord tissues. Also, 1 % CBD-cream is able to counteract the EAE-induced damage reducing release of CD4 and CD8α T cells (spleen tissue localization was quantified about 10,69 % and 35,96 % of positive staining respectively in EAE mice) and expression of the main pro-inflammatory cytokines as well as several other

  12. Chemical composition analysis and product consistency tests to support Enhanced Hanford Waste Glass Models. Results for the Augusta and October 2014 LAW Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Best, D. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-07-07

    In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for several simulated low activity waste (LAW) glasses (designated as the August and October 2014 LAW glasses) fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions.

  13. Chemical composition analysis and product consistency tests to support enhanced Hanford waste glass models: Results for the January, March, and April 2015 LAW glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Riley, W. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Best, D. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-03

    In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for several simulated low activity waste (LAW) glasses (designated as the January, March, and April 2015 LAW glasses) fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions.

  14. TH-C-18A-06: Combined CT Image Quality and Radiation Dose Monitoring Program Based On Patient Data to Assess Consistency of Clinical Imaging Across Scanner Models

    International Nuclear Information System (INIS)

    Christianson, O; Winslow, J; Samei, E

    2014-01-01

    Purpose: One of the principal challenges of clinical imaging is to achieve an ideal balance between image quality and radiation dose across multiple CT models. The number of scanners and protocols at large medical centers necessitates an automated quality assurance program to facilitate this objective. Therefore, the goal of this work was to implement an automated CT image quality and radiation dose monitoring program based on actual patient data and to use this program to assess consistency of protocols across CT scanner models. Methods: Patient CT scans are routed to a HIPPA compliant quality assurance server. CTDI, extracted using optical character recognition, and patient size, measured from the localizers, are used to calculate SSDE. A previously validated noise measurement algorithm determines the noise in uniform areas of the image across the scanned anatomy to generate a global noise level (GNL). Using this program, 2358 abdominopelvic scans acquired on three commercial CT scanners were analyzed. Median SSDE and GNL were compared across scanner models and trends in SSDE and GNL with patient size were used to determine the impact of differing automatic exposure control (AEC) algorithms. Results: There was a significant difference in both SSDE and GNL across scanner models (9–33% and 15–35% for SSDE and GNL, respectively). Adjusting all protocols to achieve the same image noise would reduce patient dose by 27–45% depending on scanner model. Additionally, differences in AEC methodologies across vendors resulted in disparate relationships of SSDE and GNL with patient size. Conclusion: The difference in noise across scanner models indicates that protocols are not optimally matched to achieve consistent image quality. Our results indicated substantial possibility for dose reduction while achieving more consistent image appearance. Finally, the difference in AEC methodologies suggests the need for size-specific CT protocols to minimize variability in image

  15. Profile consistency on TFTR

    International Nuclear Information System (INIS)

    Fredrickson, E.D.; McGuire, K.M.; Goldston, R.J.

    1987-01-01

    Electron heat transport on TFTR and other tokamaks is several orders of magnitude larger than neoclassical calculations predict. Despite considerable effort, there is still no clear theoretical understanding of this anomalous transport. The electron temperature profile, T e (r), has shown a marked consistency on many machines for a wide range of plasma parameters and heating profiles. This could be an important clue as to the process responsible for this enhanced thermal transport. In the first section of the paper the result is presented that TFTR electron temperature profile shapes are even more constrained than previous models of profile consistency suggested. The profile shapes, T e (r)/T e (a/2), are found to be invariant (for r>0.4 a) for a wide range of parameters, including q(a). In the second section, an experiment is discussed which uses a fast current ramp to transiently decouple the current density profile, J(r), and the T e (r) profiles. From this experiment, it has been determined that the J(r) profile can be strongly modified with no measureable effect on the electron temperature profile shape. Thus, while the electron temperature profile is apparently constrained, the current profile is not. (author). Letter-to-the-editor. 25 refs, 9 figs

  16. Teaching Consistency of UML Specifications

    NARCIS (Netherlands)

    Sikkel, Nicolaas; Daneva, Maia

    2010-01-01

    Consider the situation that you have a data model, a functional model and a process model of a system, perhaps made by different analysts at different times. Are these models consistent with each other? A relevant question in practice – and therefore we think it should also be addressed in our

  17. Towards a realization of the condensed-matter-gravity correspondence in string theory via consistent Abelian truncation of the Aharony-Bergman-Jafferis-Maldacena model.

    Science.gov (United States)

    Mohammed, Asadig; Murugan, Jeff; Nastase, Horatiu

    2012-11-02

    We present an embedding of the three-dimensional relativistic Landau-Ginzburg model for condensed matter systems in an N = 6, U(N) × U(N) Chern-Simons-matter theory [the Aharony-Bergman-Jafferis-Maldacena model] by consistently truncating the latter to an Abelian effective field theory encoding the collective dynamics of O(N) of the O(N(2)) modes. In fact, depending on the vacuum expectation value on one of the Aharony-Bergman-Jafferis-Maldacena scalars, a mass deformation parameter μ and the Chern-Simons level number k, our Abelianization prescription allows us to interpolate between the Abelian Higgs model with its usual multivortex solutions and a Ø(4) theory. We sketch a simple condensed matter model that reproduces all the salient features of the Abelianization. In this context, the Abelianization can be interpreted as giving a dimensional reduction from four dimensions.

  18. An elasto-plastic self-consistent model with hardening based on dislocation density, twinning and de-twinning: Application to strain path changes in HCP metals

    Energy Technology Data Exchange (ETDEWEB)

    Zecevic, Milovan [Department of Mechanical Engineering, University of New Hampshire, Durham, NH 03824 (United States); Knezevic, Marko, E-mail: marko.knezevic@unh.edu [Department of Mechanical Engineering, University of New Hampshire, Durham, NH 03824 (United States); Beyerlein, Irene J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Tomé, Carlos N. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-06-25

    In this work, we develop a polycrystal mean-field constitutive model based on an elastic–plastic self-consistent (EPSC) framework. In this model, we incorporate recently developed subgrain models for dislocation density evolution with thermally activated slip, twin activation via statistical stress fluctuations, reoriented twin domains within the grain and associated stress relaxation, twin boundary hardening, and de-twinning. The model is applied to a systematic set of strain path change tests on pure beryllium (Be). Under the applied deformation conditions, Be deforms by multiple slip modes and deformation twinning and thereby provides a challenging test for model validation. With a single set of material parameters, determined using the flow-stress vs. strain responses during monotonic testing, the model predicts well the evolution of texture, lattice strains, and twinning. With further analysis, we demonstrate the significant influence of internal residual stresses on (1) the flow stress drop when reloading from one path to another, (2) deformation twin activation, (3) de-twinning during a reversal strain path change, and (4) the formation of additional twin variants during a cross-loading sequence. The model presented here can, in principle, be applied to other metals, deforming by multiple slip and twinning modes under a wide range of temperature, strain rate, and strain path conditions.

  19. Bioavailability of particulate metal to zebra mussels: Biodynamic modelling shows that assimilation efficiencies are site-specific

    Energy Technology Data Exchange (ETDEWEB)

    Bourgeault, Adeline, E-mail: bourgeault@ensil.unilim.fr [Cemagref, Unite de Recherche Hydrosystemes et Bioprocedes, 1 rue Pierre-Gilles de Gennes, 92761 Antony (France); FIRE, FR-3020, 4 place Jussieu, 75005 Paris (France); Gourlay-France, Catherine, E-mail: catherine.gourlay@cemagref.fr [Cemagref, Unite de Recherche Hydrosystemes et Bioprocedes, 1 rue Pierre-Gilles de Gennes, 92761 Antony (France); FIRE, FR-3020, 4 place Jussieu, 75005 Paris (France); Priadi, Cindy, E-mail: cindy.priadi@eng.ui.ac.id [LSCE/IPSL CEA-CNRS-UVSQ, Avenue de la Terrasse, 91198 Gif-sur-Yvette (France); Ayrault, Sophie, E-mail: Sophie.Ayrault@lsce.ipsl.fr [LSCE/IPSL CEA-CNRS-UVSQ, Avenue de la Terrasse, 91198 Gif-sur-Yvette (France); Tusseau-Vuillemin, Marie-Helene, E-mail: Marie-helene.tusseau@ifremer.fr [IFREMER Technopolis 40, 155 rue Jean-Jacques Rousseau, 92138 Issy-Les-Moulineaux (France)

    2011-12-15

    This study investigates the ability of the biodynamic model to predict the trophic bioaccumulation of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in a freshwater bivalve. Zebra mussels were transplanted to three sites along the Seine River (France) and collected monthly for 11 months. Measurements of the metal body burdens in mussels were compared with the predictions from the biodynamic model. The exchangeable fraction of metal particles did not account for the bioavailability of particulate metals, since it did not capture the differences between sites. The assimilation efficiency (AE) parameter is necessary to take into account biotic factors influencing particulate metal bioavailability. The biodynamic model, applied with AEs from the literature, overestimated the measured concentrations in zebra mussels, the extent of overestimation being site-specific. Therefore, an original methodology was proposed for in situ AE measurements for each site and metal. - Highlights: > Exchangeable fraction of metal particles did not account for the bioavailability of particulate metals. > Need for site-specific biodynamic parameters. > Field-determined AE provide a good fit between the biodynamic model predictions and bioaccumulation measurements. - The interpretation of metal bioaccumulation in transplanted zebra mussels with biodynamic modelling highlights the need for site-specific assimilation efficiencies of particulate metals.

  20. Observable Signatures of Wind-driven Chemistry with a Fully Consistent Three-dimensional Radiative Hydrodynamics Model of HD 209458b

    Science.gov (United States)

    Drummond, B.; Mayne, N. J.; Manners, J.; Carter, A. L.; Boutle, I. A.; Baraffe, I.; Hébrard, É.; Tremblin, P.; Sing, D. K.; Amundsen, D. S.; Acreman, D.

    2018-03-01

    We present a study of the effect of wind-driven advection on the chemical composition of hot-Jupiter atmospheres using a fully consistent 3D hydrodynamics, chemistry, and radiative transfer code, the Met Office Unified Model (UM). Chemical modeling of exoplanet atmospheres has primarily been restricted to 1D models that cannot account for 3D dynamical processes. In this work, we couple a chemical relaxation scheme to the UM to account for the chemical interconversion of methane and carbon monoxide. This is done consistently with the radiative transfer meaning that departures from chemical equilibrium are included in the heating rates (and emission) and hence complete the feedback between the dynamics, thermal structure, and chemical composition. In this Letter, we simulate the well studied atmosphere of HD 209458b. We find that the combined effect of horizontal and vertical advection leads to an increase in the methane abundance by several orders of magnitude, which is directly opposite to the trend found in previous works. Our results demonstrate the need to include 3D effects when considering the chemistry of hot-Jupiter atmospheres. We calculate transmission and emission spectra, as well as the emission phase curve, from our simulations. We conclude that gas-phase nonequilibrium chemistry is unlikely to explain the model–observation discrepancy in the 4.5 μm Spitzer/IRAC channel. However, we highlight other spectral regions, observable with the James Webb Space Telescope, where signatures of wind-driven chemistry are more prominant.

  1. Bioavailability of particulate metal to zebra mussels: biodynamic modelling shows that assimilation efficiencies are site-specific.

    Science.gov (United States)

    Bourgeault, Adeline; Gourlay-Francé, Catherine; Priadi, Cindy; Ayrault, Sophie; Tusseau-Vuillemin, Marie-Hélène

    2011-12-01

    This study investigates the ability of the biodynamic model to predict the trophic bioaccumulation of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in a freshwater bivalve. Zebra mussels were transplanted to three sites along the Seine River (France) and collected monthly for 11 months. Measurements of the metal body burdens in mussels were compared with the predictions from the biodynamic model. The exchangeable fraction of metal particles did not account for the bioavailability of particulate metals, since it did not capture the differences between sites. The assimilation efficiency (AE) parameter is necessary to take into account biotic factors influencing particulate metal bioavailability. The biodynamic model, applied with AEs from the literature, overestimated the measured concentrations in zebra mussels, the extent of overestimation being site-specific. Therefore, an original methodology was proposed for in situ AE measurements for each site and metal. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Matching of motor-sensory modality in the rodent femoral nerve model shows no enhanced effect on peripheral nerve regeneration

    Science.gov (United States)

    Kawamura, David H.; Johnson, Philip J.; Moore, Amy M.; Magill, Christina K.; Hunter, Daniel A.; Ray, Wilson Z.; Tung, Thomas HH.; Mackinnon, Susan E.

    2010-01-01

    The treatment of peripheral nerve injuries with nerve gaps largely consists of autologous nerve grafting utilizing sensory nerve donors. Underlying this clinical practice is the assumption that sensory autografts provide a suitable substrate for motoneuron regeneration, thereby facilitating motor endplate reinnervation and functional recovery. This study examined the role of nerve graft modality on axonal regeneration, comparing motor nerve regeneration through motor, sensory, and mixed nerve isografts in the Lewis rat. A total of 100 rats underwent grafting of the motor or sensory branch of the femoral nerve with histomorphometric analysis performed after 5, 6, or 7 weeks. Analysis demonstrated similar nerve regeneration in motor, sensory, and mixed nerve grafts at all three time points. These data indicate that matching of motor-sensory modality in the rat femoral nerve does not confer improved axonal regeneration through nerve isografts. PMID:20122927

  3. An integrated proteomics approach shows synaptic plasticity changes in an APP/PS1 Alzheimer's mouse model

    DEFF Research Database (Denmark)

    Kempf, Stefan J; Metaxas, Athanasios; Ibáñez-Vea, María

    2016-01-01

    The aim of this study was to elucidate the molecular signature of Alzheimer's disease-associated amyloid pathology.We used the double APPswe/PS1ΔE9 mouse, a widely used model of cerebral amyloidosis, to compare changes in proteome, including global phosphorylation and sialylated N-linked glycosyl...

  4. 14 Days of supplementation with blueberry extract shows anti-atherogenic properties and improves oxidative parameters in hypercholesterolemic rats model.

    Science.gov (United States)

    Ströher, Deise Jaqueline; Escobar Piccoli, Jacqueline da Costa; Güllich, Angélica Aparecida da Costa; Pilar, Bruna Cocco; Coelho, Ritiéle Pinto; Bruno, Jamila Benvegnú; Faoro, Debora; Manfredini, Vanusa

    2015-01-01

    The effects of supplementation with blueberry (BE) extract (Vaccinium ashei Reade) for 14 consecutive days on biochemical, hematological, histopathological and oxidative parameters in hypercholesterolemic rats were investigated. After supplementation with lyophilized extract of BE, the levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides were decreased. Histopathological analysis showed significant decrease (p < 0.05) of aortic lesions in hypercholesterolemic rats. Oxidative parameters showed significant reductions (p < 0.05) in oxidative damage to lipids and proteins and an increase in activities of antioxidant enzymes such as catalase, superoxide dismutase and glutathione peroxidase. The BE extract showed an important cardioprotective effect by the improvements in the serum lipid profile, antioxidant system, particularly in reducing oxidative stress associated with hypercholesterolemia and anti-atherogenic effect in rats.

  5. Advanced imaging techniques show progressive arthropathy following experimentally induced knee bleeding in a factor VIII-/- rat model

    DEFF Research Database (Denmark)

    Sorensen, K. R.; Roepstorff, K.; Petersen, M.

    2015-01-01

    Background: Joint pathology is most commonly assessed by radiogra-phy, but ultrasonography (US) is increasingly recognized for its acces-sibility, safety and ability to show soft tissue changes, the earliestindicators of haemophilic arthropathy (HA). US, however, lacks theability to visualize...

  6. Automated home cage assessment shows behavioral changes in a transgenic mouse model of spinocerebellar ataxia type 17.

    Science.gov (United States)

    Portal, Esteban; Riess, Olaf; Nguyen, Huu Phuc

    2013-08-01

    Spinocerebellar Ataxia type 17 (SCA17) is an autosomal dominantly inherited, neurodegenerative disease characterized by ataxia, involuntary movements, and dementia. A novel SCA17 mouse model having a 71 polyglutamine repeat expansion in the TATA-binding protein (TBP) has shown age related motor deficit using a classic motor test, yet concomitant weight increase might be a confounding factor for this measurement. In this study we used an automated home cage system to test several motor readouts for this same model to confirm pathological behavior results and evaluate benefits of automated home cage in behavior phenotyping. Our results confirm motor deficits in the Tbp/Q71 mice and present previously unrecognized behavioral characteristics obtained from the automated home cage, indicating its use for high-throughput screening and testing, e.g. of therapeutic compounds. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. BO-1055, a novel DNA cross-linking agent with remarkable low myelotoxicity shows potent activity in sarcoma models

    OpenAIRE

    Ambati, Srikanth R.; Shieh, Jae-Hung; Pera, Benet; Lopes, Eloisi Caldas; Chaudhry, Anisha; Wong, Elissa W.P.; Saxena, Ashish; Su, Tsann-Long; Moore, Malcolm A.S.

    2016-01-01

    DNA damaging agents cause rapid shrinkage of tumors and form the basis of chemotherapy for sarcomas despite significant toxicities. Drugs having superior efficacy and wider therapeutic windows are needed to improve patient outcomes. We used cell proliferation and apoptosis assays in sarcoma cell lines and benign cells; ?-H2AX expression, comet assay, immunoblot analyses and drug combination studies in vitro and in patient derived xenograft (PDX) models. BO-1055 caused apoptosis and cell death...

  8. Betting on change: Tenet deal with Vanguard shows it's primed to try ACO effort, new payment model.

    Science.gov (United States)

    Kutscher, Beth

    2013-07-01

    Tenet Healthcare Corp.'s acquisition of Vanguard Health Systems is a sign the investor-owned chain is willing to take a chance on alternative payment models such as accountable care organizations. There's no certainty that ACOs will deliver the improvements on quality or cost savings, but Vanguard Vice Chairman Keith Pitts, left, says his system's Pioneer ACO in Detroit has already achieved some cost savings.

  9. Restless led syndrome model Drosophila melanogaster show successful olfactory learning and 1-day retention of the acquired memory

    OpenAIRE

    Mika F. Asaba; Adrian A. Bates; Hoa M. Dao; Mika J. Maeda

    2013-01-01

    Restless Legs Syndrome (RLS) is a prevalent but poorly understood disorder that ischaracterized by uncontrollable movements during sleep, resulting in sleep disturbance.Olfactory memory in Drosophila melanogaster has proven to be a useful tool for the study ofcognitive deficits caused by sleep disturbances, such as those seen in RLS. A recently generatedDrosophila model of RLS exhibited disturbed sleep patterns similar to those seen in humans withRLS. This research seeks to improve understand...

  10. Consistent lattice Boltzmann modeling of low-speed isothermal flows at finite Knudsen numbers in slip-flow regime: Application to plane boundaries.

    Science.gov (United States)

    Silva, Goncalo; Semiao, Viriato

    2017-07-01

    The first nonequilibrium effect experienced by gaseous flows in contact with solid surfaces is the slip-flow regime. While the classical hydrodynamic description holds valid in bulk, at boundaries the fluid-wall interactions must consider slip. In comparison to the standard no-slip Dirichlet condition, the case of slip formulates as a Robin-type condition for the fluid tangential velocity. This makes its numerical modeling a challenging task, particularly in complex geometries. In this work, this issue is handled with the lattice Boltzmann method (LBM), motivated by the similarities between the closure relations of the reflection-type boundary schemes equipping the LBM equation and the slip velocity condition established by slip-flow theory. Based on this analogy, we derive, as central result, the structure of the LBM boundary closure relation that is consistent with the second-order slip velocity condition, applicable to planar walls. Subsequently, three tasks are performed. First, we clarify the limitations of existing slip velocity LBM schemes, based on discrete analogs of kinetic theory fluid-wall interaction models. Second, we present improved slip velocity LBM boundary schemes, constructed directly at discrete level, by extending the multireflection framework to the slip-flow regime. Here, two classes of slip velocity LBM boundary schemes are considered: (i) linear slip schemes, which are local but retain some calibration requirements and/or operation limitations, (ii) parabolic slip schemes, which use a two-point implementation but guarantee the consistent prescription of the intended slip velocity condition, at arbitrary plane wall discretizations, further dispensing any numerical calibration procedure. Third and final, we verify the improvements of our proposed slip velocity LBM boundary schemes against existing ones. The numerical tests evaluate the ability of the slip schemes to exactly accommodate the steady Poiseuille channel flow solution, over

  11. Consistent lattice Boltzmann modeling of low-speed isothermal flows at finite Knudsen numbers in slip-flow regime: Application to plane boundaries

    Science.gov (United States)

    Silva, Goncalo; Semiao, Viriato

    2017-07-01

    The first nonequilibrium effect experienced by gaseous flows in contact with solid surfaces is the slip-flow regime. While the classical hydrodynamic description holds valid in bulk, at boundaries the fluid-wall interactions must consider slip. In comparison to the standard no-slip Dirichlet condition, the case of slip formulates as a Robin-type condition for the fluid tangential velocity. This makes its numerical modeling a challenging task, particularly in complex geometries. In this work, this issue is handled with the lattice Boltzmann method (LBM), motivated by the similarities between the closure relations of the reflection-type boundary schemes equipping the LBM equation and the slip velocity condition established by slip-flow theory. Based on this analogy, we derive, as central result, the structure of the LBM boundary closure relation that is consistent with the second-order slip velocity condition, applicable to planar walls. Subsequently, three tasks are performed. First, we clarify the limitations of existing slip velocity LBM schemes, based on discrete analogs of kinetic theory fluid-wall interaction models. Second, we present improved slip velocity LBM boundary schemes, constructed directly at discrete level, by extending the multireflection framework to the slip-flow regime. Here, two classes of slip velocity LBM boundary schemes are considered: (i) linear slip schemes, which are local but retain some calibration requirements and/or operation limitations, (ii) parabolic slip schemes, which use a two-point implementation but guarantee the consistent prescription of the intended slip velocity condition, at arbitrary plane wall discretizations, further dispensing any numerical calibration procedure. Third and final, we verify the improvements of our proposed slip velocity LBM boundary schemes against existing ones. The numerical tests evaluate the ability of the slip schemes to exactly accommodate the steady Poiseuille channel flow solution, over

  12. Storm surge and wave simulations in the Gulf of Mexico using a consistent drag relation for atmospheric and storm surge models

    Directory of Open Access Journals (Sweden)

    D. Vatvani

    2012-07-01

    results obtained, we conclude that, for a good reproduction of the storm surges under hurricane conditions, Makin's new drag parameterization is favourable above the traditional Charnock relation. Furthermore, we are encouraged by these results to continue the studies and establish the effect of improved Makin's wind drag parameterization in the wave model.

    The results from this study will be used to evaluate the relevance of extending the present towards implementation of a similar wind drag parameterization in the SWAN wave model, in line with our aim to apply a consistent wind drag formulation throughout the entire storm surge modelling approach.

  13. CP-809,101, a selective 5-HT2C agonist, shows activity in animal models of antipsychotic activity.

    Science.gov (United States)

    Siuciak, Judith A; Chapin, Douglas S; McCarthy, Sheryl A; Guanowsky, Victor; Brown, Janice; Chiang, Phoebe; Marala, Ravi; Patterson, Terrell; Seymour, Patricia A; Swick, Andrew; Iredale, Philip A

    2007-02-01

    CP-809,101 is a potent, functionally selective 5-HT(2C) agonist that displays approximately 100% efficacy in vitro. The aim of the present studies was to assess the efficacy of a selective 5-HT(2C) agonist in animal models predictive of antipsychotic-like efficacy and side-effect liability. Similar to currently available antipsychotic drugs, CP-809,101 dose-dependently inhibited conditioned avoidance responding (CAR, ED(50)=4.8 mg/kg, sc). The efficacy of CP-809,101 in CAR was completely antagonized by the concurrent administration of the 5-HT(2C) receptor antagonist, SB-224,282. CP-809,101 antagonized both PCP- and d-amphetamine-induced hyperactivity with ED(50) values of 2.4 and 2.9 mg/kg (sc), respectively and also reversed an apomorphine induced-deficit in prepulse inhibition. At doses up to 56 mg/kg, CP-809,101 did not produce catalepsy. Thus, the present results demonstrate that the 5-HT(2C) agonist, CP-809,101, has a pharmacological profile similar to that of the atypical antipsychotics with low extrapyramidal symptom liability. CP-809,101 was inactive in two animal models of antidepressant-like activity, the forced swim test and learned helplessness. However, CP-809,101 was active in novel object recognition, an animal model of cognitive function. These data suggest that 5-HT(2C) agonists may be a novel approach in the treatment of psychosis as well as for the improvement of cognitive dysfunction associated with schizophrenia.

  14. Combining floating continents and a free surface in a 3D spherical mantle convection model with self-consistent plate tectonics

    Science.gov (United States)

    Rolf, T.; Crameri, F.; Tackley, P. J.

    2012-04-01

    The dynamics of the Earth's lithosphere and mantle are strongly influenced by its upper mechanical boundary condition. For instance, our previous work has shown that a necessity for the evolution of Earth-like, single-sided subduction is a free surface, which allows for vertical movement of the two converging plates, i.e. the development of surface topography [Crameri et al (2012), in press]. Single-sided subduction has an important effect on the evolution of self-consistent plate tectonics, e.g. by shaping subduction trenches. However, due to the usage of a homogeneous, i.e. purely oceanic, lithosphere these models tend to favour the rigid lid mode of plate tectonics for a realistic strength of the lithosphere, which is in contradiction to the present-day Earth. In contrast, our previous work with a pre-existing heterogeneous structure of the lithosphere has shown that the presence of continents floating at the top of the mantle may play an important role in the evolution of plate tectonics. Convective stresses may be focussed at the rheological boundary between continent and ocean, which facilitates the formation of plate boundaries and makes the Earth-like, mobile lid mode of plate tectonics easier to observe [Rolf & Tackley (2011)]. However, in these models subduction is single-sided when one oceanic and one continental plate converge, but double-sided in the case of two converging oceanic plates. Taking the previous findings as a motivation, we now combine both ingredients: the free surface and the heterogeneous lithosphere, in one self-consistent model. We approximate the free surface by using a "sticky air" layer [Schmeling et al, 2008; Crameri et al., submitted] and the continents by strong Archaean cratons, which can resist recycling on long timescales [Rolf & Tackley (2011)]. Such a model might produce single-sided subduction that is continuously evolving supported by the presence of continents. Performing global-scale self-consistent mantle convection

  15. A self-consistent three-dimensional model of the arc, electrode and weld pool in gas-metal arc welding

    International Nuclear Information System (INIS)

    Murphy, Anthony B

    2011-01-01

    The development of a three-dimensional computational model of gas-metal arc welding is described. The wire electrode, arc plasma and weld pool are included in the computational domain self-consistently. The model takes into account the motion of the electrode, flow in the weld pool, deformation of the weld-pool surface and the influence of metal droplet transfer. Results are presented for welding of an aluminium alloy. The current density distribution at the interface between the arc and the weld pool is strongly dependent on the surface profile of the weld pool. This in turn affects the temperature distribution in the weld pool. The momentum transferred by the droplet affects the direction of flow in the weld pool, and together with the energy transfer, increases the weld-pool depth. The results demonstrate the importance of including the arc plasma in the computational domain. Fair agreement is found between a measured weld profile and the predictions of the model. Inclusion of the influence of metal vapour in the model is expected to improve the agreement.

  16. Self-consistent Random Phase Approximation applied to a schematic model of the field theory; Approximation des phases aleatoires self-consistante appliquee a un modele schematique de la theorie des champs

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, Thierry [Inst. de Physique Nucleaire, Lyon-1 Univ., 69 - Villeurbanne (France)

    1998-12-11

    The self-consistent Random Phase Approximation (SCRPA) is a method allowing in the mean-field theory inclusion of the correlations in the ground and excited states. It has the advantage of not violating the Pauli principle in contrast to RPA, that is based on the quasi-bosonic approximation; in addition, numerous applications in different domains of physics, show a possible variational character. However, the latter should be formally demonstrated. The first model studied with SCRPA is the anharmonic oscillator in the region where one of its symmetries is spontaneously broken. The ground state energy is reproduced by SCRPA more accurately than RPA, with no violation of the Ritz variational principle, what is not the case for the latter approximation. The success of SCRPA is the the same in case of ground state energy for a model mixing bosons and fermions. At the transition point the SCRPA is correcting RPA drastically, but far from this region the correction becomes negligible, both methods being of similar precision. In the deformed region in the case of RPA a spurious mode occurred due to the microscopical character of the model.. The SCRPA may also reproduce this mode very accurately and actually it coincides with an excitation in the exact spectrum 40 refs., 33 figs., 14 tabs.

  17. Pridopidine, a dopamine stabilizer, improves motor performance and shows neuroprotective effects in Huntington disease R6/2 mouse model.

    Science.gov (United States)

    Squitieri, Ferdinando; Di Pardo, Alba; Favellato, Mariagrazia; Amico, Enrico; Maglione, Vittorio; Frati, Luigi

    2015-11-01

    Huntington disease (HD) is a neurodegenerative disorder for which new treatments are urgently needed. Pridopidine is a new dopaminergic stabilizer, recently developed for the treatment of motor symptoms associated with HD. The therapeutic effect of pridopidine in patients with HD has been determined in two double-blind randomized clinical trials, however, whether pridopidine exerts neuroprotection remains to be addressed. The main goal of this study was to define the potential neuroprotective effect of pridopidine, in HD in vivo and in vitro models, thus providing evidence that might support a potential disease-modifying action of the drug and possibly clarifying other aspects of pridopidine mode-of-action. Our data corroborated the hypothesis of neuroprotective action of pridopidine in HD experimental models. Administration of pridopidine protected cells from apoptosis, and resulted in highly improved motor performance in R6/2 mice. The anti-apoptotic effect observed in the in vitro system highlighted neuroprotective properties of the drug, and advanced the idea of sigma-1-receptor as an additional molecular target implicated in the mechanism of action of pridopidine. Coherent with protective effects, pridopidine-mediated beneficial effects in R6/2 mice were associated with an increased expression of pro-survival and neurostimulatory molecules, such as brain derived neurotrophic factor and DARPP32, and with a reduction in the size of mHtt aggregates in striatal tissues. Taken together, these findings support the theory of pridopidine as molecule with disease-modifying properties in HD and advance the idea of a valuable therapeutic strategy for effectively treating the disease. © 2015 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  18. THREE-DIMENSIONAL ATMOSPHERIC CIRCULATION MODELS OF HD 189733b AND HD 209458b WITH CONSISTENT MAGNETIC DRAG AND OHMIC DISSIPATION

    International Nuclear Information System (INIS)

    Rauscher, Emily; Menou, Kristen

    2013-01-01

    We present the first three-dimensional circulation models for extrasolar gas giant atmospheres with geometrically and energetically consistent treatments of magnetic drag and ohmic dissipation. Atmospheric resistivities are continuously updated and calculated directly from the flow structure, strongly coupling the magnetic effects with the circulation pattern. We model the hot Jupiters HD 189733b (T eq ≈ 1200 K) and HD 209458b (T eq ≈ 1500 K) and test planetary magnetic field strengths from 0 to 30 G. We find that even at B = 3 G the atmospheric structure and circulation of HD 209458b are strongly influenced by magnetic effects, while the cooler HD 189733b remains largely unaffected, even in the case of B = 30 G and super-solar metallicities. Our models of HD 209458b indicate that magnetic effects can substantially slow down atmospheric winds, change circulation and temperature patterns, and alter observable properties. These models establish that longitudinal and latitudinal hot spot offsets, day-night flux contrasts, and planetary radius inflation are interrelated diagnostics of the magnetic induction process occurring in the atmospheres of hot Jupiters and other similarly forced exoplanets. Most of the ohmic heating occurs high in the atmosphere and on the dayside of the planet, while the heating at depth is strongly dependent on the internal heat flux assumed for the planet, with more heating when the deep atmosphere is hot. We compare the ohmic power at depth in our models, and estimates of the ohmic dissipation in the bulk interior (from general scaling laws), to evolutionary models that constrain the amount of heating necessary to explain the inflated radius of HD 209458b. Our results suggest that deep ohmic heating can successfully inflate the radius of HD 209458b for planetary magnetic field strengths of B ≥ 3-10 G.

  19. Accurate and self-consistent procedure for determining pH in seawater desalination brines and its manifestation in reverse osmosis modeling.

    Science.gov (United States)

    Nir, Oded; Marvin, Esra; Lahav, Ori

    2014-11-01

    Measuring and modeling pH in concentrated aqueous solutions in an accurate and consistent manner is of paramount importance to many R&D and industrial applications, including RO desalination. Nevertheless, unified definitions and standard procedures have yet to be developed for solutions with ionic strength higher than ∼0.7 M, while implementation of conventional pH determination approaches may lead to significant errors. In this work a systematic yet simple methodology for measuring pH in concentrated solutions (dominated by Na(+)/Cl(-)) was developed and evaluated, with the aim of achieving consistency with the Pitzer ion-interaction approach. Results indicate that the addition of 0.75 M of NaCl to NIST buffers, followed by assigning a new standard pH (calculated based on the Pitzer approach), enabled reducing measured errors to below 0.03 pH units in seawater RO brines (ionic strength up to 2 M). To facilitate its use, the method was developed to be both conceptually and practically analogous to the conventional pH measurement procedure. The method was used to measure the pH of seawater RO retentates obtained at varying recovery ratios. The results matched better the pH values predicted by an accurate RO transport model. Calibrating the model by the measured pH values enabled better boron transport prediction. A Donnan-induced phenomenon, affecting pH in both retentate and permeate streams, was identified and quantified. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Zonulin transgenic mice show altered gut permeability and increased morbidity/mortality in the DSS colitis model.

    Science.gov (United States)

    Sturgeon, Craig; Lan, Jinggang; Fasano, Alessio

    2017-06-01

    Increased small intestinal permeability (IP) has been proposed to be an integral element, along with genetic makeup and environmental triggers, in the pathogenies of chronic inflammatory diseases (CIDs). We identified zonulin as a master regular of intercellular tight junctions linked to the development of several CIDs. We aim to study the role of zonulin-mediated IP in the pathogenesis of CIDs. Zonulin transgenic Hp2 mice (Ztm) were subjected to dextran sodium sulfate (DSS) treatment for 7 days, followed by 4-7 days' recovery and compared to C57Bl/6 (wild-type (WT)) mice. IP was measured in vivo and ex vivo, and weight, histology, and survival were monitored. To mechanistically link zonulin-dependent impairment of small intestinal barrier function with clinical outcome, Ztm were treated with the zonulin inhibitor AT1001 added to drinking water in addition to DSS. We observed increased morbidity (more pronounced weight loss and colitis) and mortality (40-70% compared with 0% in WT) at 11 days post-DSS treatment in Ztm compared with WT mice. Both in vivo and ex vivo measurements showed an increased IP at baseline in Ztm compared to WT mice, which was exacerbated by DSS treatment and was associated with upregulation of zonulin gene expression (fourfold in the duodenum, sixfold in the jejunum). Treatment with AT1001 prevented the DSS-induced increased IP both in vivo and ex vivo without changing zonulin gene expression and completely reverted morbidity and mortality in Ztm. Our data show that zonulin-dependent small intestinal barrier impairment is an early step leading to the break of tolerance with subsequent development of CIDs. © 2017 New York Academy of Sciences.

  1. Self-consistent modeling of entangled network strands and linear dangling structures in a single-strand mean-field slip-link model

    DEFF Research Database (Denmark)

    Jensen, Mette Krog; Khaliullin, Renat; Schieber, Jay D.

    2012-01-01

    knowledge about the effect of dangling ends and soluble structures. To interpret our recent experimental results, we exploit a molecular model that can predict LVE data and non-linear stress–strain data. The slip-link model has proven to be a robust tool for both LVE and non-linear stress–strain predictions...... strands in the ensemble are attached to the network in both ends. Next we add dangling strands to the network representing the stoichiometric imbalance, or imperfections during curing. By considering monodisperse network strands without dangling ends, we find that the relative low-frequency plateau, G0/GN......0G0G0N, decreases linearly with the average number of entanglements. The decrease from GN0G0N to G 0 is a result of monomer fluctuations between entanglements, which is similar to “longitudinal modes” in tube theory. It is found that the slope of G′ is dependent on the fraction of network strands...

  2. Amniotic fluid stem cells with low γ-interferon response showed behavioral improvement in Parkinsonism rat model.

    Directory of Open Access Journals (Sweden)

    Yu-Jen Chang

    Full Text Available Amniotic fluid stem cells (AFSCs are multipotent stem cells that may be used in transplantation medicine. In this study, AFSCs established from amniocentesis were characterized on the basis of surface marker expression and differentiation potential. To further investigate the properties of AFSCs for translational applications, we examined the cell surface expression of human leukocyte antigens (HLA of these cells and estimated the therapeutic effect of AFSCs in parkinsonian rats. The expression profiles of HLA-II and transcription factors were compared between AFSCs and bone marrow-derived mesenchymal stem cells (BMMSCs following treatment with γ-IFN. We found that stimulation of AFSCs with γ-IFN prompted only a slight increase in the expression of HLA-Ia and HLA-E, and the rare HLA-II expression could also be observed in most AFSCs samples. Consequently, the expression of CIITA and RFX5 was weakly induced by γ-IFN stimulation of AFSCs compared to that of BMMSCs. In the transplantation test, Sprague Dawley rats with 6-hydroxydopamine lesioning of the substantia nigra were used as a parkinsonian-animal model. Following the negative γ-IFN response AFSCs injection, apomorphine-induced rotation was reduced by 75% in AFSCs engrafted parkinsonian rats but was increased by 53% in the control group after 12-weeks post-transplantation. The implanted AFSCs were viable, and were able to migrate into the brain's circuitry and express specific proteins of dopamine neurons, such as tyrosine hydroxylase and dopamine transporter. In conclusion, the relative insensitivity AFSCs to γ-IFN implies that AFSCs might have immune-tolerance in γ-IFN inflammatory conditions. Furthermore, the effective improvement of AFSCs transplantation for apomorphine-induced rotation paves the way for the clinical application in parkinsonian therapy.

  3. Hybrid method for consistent model of the Pacific absolute plate motion and a test for inter-hotspot motion since 70Ma

    Science.gov (United States)

    Harada, Y.; Wessel, P.; Sterling, A.; Kroenke, L.

    2002-12-01

    Inter-hotspot motion within the Pacific plate is one of the most controversial issues in recent geophysical studies. However, it is a fact that many geophysical and geological data including ages and positions of seamount chains in the Pacific plate can largely be explained by a simple model of absolute motion derived from assumptions of rigid plates and fixed hotspots. Therefore we take the stand that if a model of plate motion can explain the ages and positions of Pacific hotspot tracks, inter-hotspot motion would not be justified. On the other hand, if any discrepancies between the model and observations are found, the inter-hotspot motion may then be estimated from these discrepancies. To make an accurate model of the absolute motion of the Pacific plate, we combined two different approaches: the polygonal finite rotation method (PFRM) by Harada and Hamano (2000) and the hot-spotting technique developed by Wessel and Kroenke (1997). The PFRM can determine accurate positions of finite rotation poles for the Pacific plate if the present positions of hotspots are known. On the other hand, the hot-spotting technique can predict present positions of hotspots if the absolute plate motion is given. Therefore we can undertake iterative calculations using the two methods. This hybrid method enables us to determine accurate finite rotation poles for the Pacific plate solely from geometry of Hawaii, Louisville and Easter(Crough)-Line hotspot tracks from around 70 Ma to present. Information of ages can be independently assigned to the model after the poles and rotation angles are determined. We did not detect any inter-hotspot motion from the geometry of these Pacific hotspot tracks using this method. The Ar-Ar ages of Pacific seamounts including new age data of ODP Leg 197 are used to test the newly determined model of the Pacific plate motion. The ages of Hawaii, Louisville, Easter(Crough)-Line, and Cobb hotspot tracks are quite consistent with each other from 70 Ma to

  4. LIDT-DD: A new self-consistent debris disc model that includes radiation pressure and couples dynamical and collisional evolution

    Science.gov (United States)

    Kral, Q.; Thébault, P.; Charnoz, S.

    2013-10-01

    Context. In most current debris disc models, the dynamical and the collisional evolutions are studied separately with N-body and statistical codes, respectively, because of stringent computational constraints. In particular, incorporating collisional effects (especially destructive collisions) into an N-body scheme has proven a very arduous task because of the exponential increase of particles it would imply. Aims: We present here LIDT-DD, the first code able to mix both approaches in a fully self-consistent way. Our aim is for it to be generic enough to be applied to any astrophysical case where we expect dynamics and collisions to be deeply interlocked with one another: planets in discs, violent massive breakups, destabilized planetesimal belts, bright exozodiacal discs, etc. Methods: The code takes its basic architecture from the LIDT3D algorithm for protoplanetary discs, but has been strongly modified and updated to handle the very constraining specificities of debris disc physics: high-velocity fragmenting collisions, radiation-pressure affected orbits, absence of gas that never relaxes initial conditions, etc. It has a 3D Lagrangian-Eulerian structure, where grains of a given size at a given location in a disc are grouped into super-particles or tracers whose orbits are evolved with an N-body code and whose mutual collisions are individually tracked and treated using a particle-in-a-box prescription designed to handle fragmenting impacts. To cope with the wide range of possible dynamics for same-sized particles at any given location in the disc, and in order not to lose important dynamical information, tracers are sorted and regrouped into dynamical families depending on their orbits. A complex reassignment routine that searches for redundant tracers in each family and reassignes them where they are needed, prevents the number of tracers from diverging. Results: The LIDT-DD code has been successfully tested on simplified cases for which robust results have

  5. Application of discrete solvent reaction field model with self-consistent atomic charges and atomic polarizabilities to calculate the χ(1) and χ(2) of organic molecular crystals

    Science.gov (United States)

    Lu, Shih-I.

    2018-01-01

    We use the discrete solvent reaction field model to evaluate the linear and second-order nonlinear optical susceptibilities of 3-methyl-4-nitropyridine-1-oxyde crystal. In this approach, crystal environment is created by supercell architecture. A self-consistent procedure is used to obtain charges and polarizabilities for environmental atoms. Impact of atomic polarizabilities on the properties of interest is highlighted. This approach is shown to give the second-order nonlinear optical susceptibilities within error bar of experiment as well as the linear optical susceptibilities in the same order as experiment. Similar quality of calculations are also applied to both 4-N,N-dimethylamino-3-acetamidonitrobenzene and 2-methyl-4-nitroaniline crystals.

  6. Consistent integration of geo-information

    Science.gov (United States)

    Hansen, T. M.; Cordua, K. S.

    2014-12-01

    Probabilistically formulated inverse problems can be seen as an application of data integration. Two types of information are (almost) always available: 1) geophysical data, and 2) information about geology and geologically plausible structures. The inverse problem consists of integrating the information available from geophysical data and geological information. In recent years inversion algorithms have emerged that allow integration of such different information. However such methods only provides useful results if the geological and geophysical information provided are consistent. Using weakly informed prior models and/or sparse uncertain geophysical data typically no problems with consistency arise. However, as data coverage and quality increase and still more complex and detailed prior information can be quantified (using e.g multiple point based statistics) then the risk of problems with consistency increases. Inconsistency between two independent sources of information about the same subsurface model, means that either one or both sources of information must be wrong.We will demonstrate that using cross hole GPR tomographic data, that such consistency problems exist, and that they can dramatically affect inversion results. The problem is two folded: 1) One will typically underestimate the error associated with geophysical data, and 2) Multiple-point based prior models often provide such detailed a priori information that it will not be possible to find a priori acceptable models that lead to a data fit within measurement uncertainties. We demonstrate that if inversion is forced on inconsistent information, then the solution to the inverse problem may be earth models that neither fit the data within their uncertainty, nor represent realistic geologically features. In the worst case such models will show artefacts that appear well resolved, and that can have severe effect on subsequent flow modeling. We will demonstrate how such inconsistencies can be

  7. Comparison of strength, consistency, and speed of COR-KNOT versus manually hand-tied knots in an ex vivo minimally invasive model.

    Science.gov (United States)

    Lee, Candice Y; Sauer, Jude S; Gorea, Heather R; Martellaro, Angelo J; Knight, Peter A

    2014-01-01

    This study compared the strength, consistency, and speed of prosthetic attachment sutures secured with automated fasteners with those of manual knots using an ex vivo porcine mitral valve annuloplasty model. A novel miniature pressure transducer system was developed to quantify pressures between sutured prosthetic rings and underlying cardiac tissue. Sixteen mitral annuloplasty rings were sewn into ex vivo pig hearts. Eight rings were secured with the COR-KNOT device; and eight rings, with hand-tied knots using a knot pusher. A cardiac surgeon and a surgery resident each completed four manually tied rings and four COR-KNOT rings via a thoracotomy trainer. The total time to knot and cut each ring's sutures was recorded. Suture attachment pressures were measured within (intrasuture) and between (extrasuture) each suture loop using a 0.5 × 2.0-mm microtransducer probe system. The suture holding pressures for the COR-KNOT fasteners were significantly greater than for the manually tied knots (median, 1008.9 vs 415.8 mm Hg, P COR-KNOT fasteners than for the hand-tied knots (SD, 401.6 vs 499.3 mm Hg, P = 0.04). Significant time savings occurred with the use of the COR-KNOT compared with manual tying (12.4 vs 71.1 seconds per knot, P = 0.001). The novel microtransducer technology provided an innovative means of evaluating cardiac prosthetic anchoring sutures. In this model, mitral annuloplasty ring sutures secured with the COR-KNOT device were stronger, more consistent, and faster than with manually tied knots.

  8. Universe of quantum whirls in the final theory spiral field model. Basic ideas for a compatible physics and a consistent nature science. 3. rev. ed.

    International Nuclear Information System (INIS)

    Hartje, Udo A.J.

    2008-01-01

    Internationally stressed physics is looking for the solution of the basic problems of physics at higher and higher energies in impressive plants which outbid themselves in their expenditure for technology reciprocally. If with this manner shall be to seek the ''atomos'' and the ''unit of the physics'' then this is an error way. Sought-after Higgs particles are certainly not a simply thing; but a most complex object which would contain an enormous number of effect quanta in its structure. Since Planck, Poincare, Einstein, Bohr, Heisenberg, Schroedinger, De Broglie and others well-known physicists we know that this ''atomos'' have only a tiny energy quantity which single is not measurable. The search with gigantic machines is at all besides more nonsensical than such processes there will pump even energy into it. The elementary contains only fractions from the energy what is in known smallest particles or weakest beams too. This work follows another approach to grasp the nature in a Final Theory (Grand Unification) on a deductive way. It starts from a most general analysis and synthesis of scientific and everyday-language concepts. This shored up it on the principle of general physical field. The dynamic processes of the field are vivid illustrated by graphic means in systems of coordinates with space-time. Through it arises a everywhere consistent view for most simple existences and simple structures up to most complicate existences for all fields of physics and philosophy. That remained shut off till now obstinately for the cognition. A important result is the solution of the puzzle of ''Dualism of Wave and Particle''. Matter-structures consist not from 'a priori' existing 'little verdicts' which secondary swing. But they consist from beams; which remain in the inside of the particles radiation-like: and they rotate there in themselves. This creates locality without changing the radiation itself into 'electrons' which rotate on paths. The Classical Physics and the

  9. Universe of quantum whirls in the final theory spiral field model. Basic ideas for a compatible physics and a consistent nature science. 2. rev. ed.

    International Nuclear Information System (INIS)

    Hartje, Udo A.J.

    2007-01-01

    Internationally stressed physics is looking for the solution of the basic problems of physics at higher and higher energies in impressive plants which outbid themselves in their expenditure for technology reciprocally. If with this manner shall be to seek the ''atomos'' and the ''unit of the physics'' then this is an error way. Sought-after Higgs particles are certainly not a simply thing; but a most complex object which would contain an enormous number of effect quanta in its structure. Since Planck, Poincare, Einstein, Bohr, Heisenberg, Schroedinger, De Broglie and others well-known physicists we know that this ''atomos'' have only a tiny energy quantity which single is not measurable. The search with gigantic machines is at all besides more nonsensical than such processes there will pump even energy into it. The elementary contains only fractions from the energy what is in known smallest particles or weakest beams too. This work follows another approach to grasp the nature in a Final Theory (Grand Unification) on a deductive way. It starts from a most general analysis and synthesis of scientific and everyday-language concepts. This shored up it on the principle of general physical field. The dynamic processes of the field are vivid illustrated by graphic means in systems of coordinates with space-time. Through it arises a everywhere consistent view for most simple existences and simple structures up to most complicate existences for all fields of physics and philosophy. That remained shut off till now obstinately for the cognition. A important result is the solution of the puzzle of ''Dualism of Wave and Particle''. Matter-structures consist not from 'a priori' existing 'little verdicts' which secondary swing. But they consist from beams; which remain in the inside of the particles radiation-like: and they rotate there in themselves. This creates locality without changing the radiation itself into 'electrons' which rotate on paths. The Classical Physics and the

  10. Modeling intra- and intermolecular correlations for linear and branched polymers using a modified test-chain self-consistent field theory.

    Science.gov (United States)

    Hu, Renfeng; Wu, David T; Wang, Dapeng

    2017-04-01

    A modified test-chain self-consistent field theory (SCFT) is presented to study the intra- and intermolecular correlations of linear and branched polymers in various solutions and melts. The key to the test-chain SCFT is to break the the translational symmetry by fixing a monomer at the origin of a coordinate. This theory successfully describes the crossover from self-avoiding walk at short distances to screened random walk at long distances in a semidilute solution or melt. The calculations indicated that branching enhances the swelling of polymers in melts and influences stretching at short distances. The test-chain SCFT calculations show good agreement with experiments and classic polymer theories. We highlight that the theory presented here provides a solution to interpret the polymer conformation and behavior under various conditions within the framework of one theory.

  11. Self-consistent quark bags

    International Nuclear Information System (INIS)

    Rafelski, J.

    1979-01-01

    After an introductory overview of the bag model the author uses the self-consistent solution of the coupled Dirac-meson fields to represent a bound state of strongly ineteracting fermions. In this framework he discusses the vivial approach to classical field equations. After a short description of the used numerical methods the properties of bound states of scalar self-consistent Fields and the solutions of a self-coupled Dirac field are considered. (HSI) [de

  12. Tracers of diabatic changes in potential temperature and potential vorticity: Integral interpretation in terms of net heating and circulation and applications to model consistency across resolutions

    Science.gov (United States)

    Martinez-Alvarado, Oscar; Gray, Suzanne; Methven, John

    2016-04-01

    Diabatic processes in the atmosphere can be characterised by the changes they produce on potential temperature (θ) and potential vorticity (PV) following an air parcel. Diabatic tracers of θ and PV track the changes undergone by those two variables due to the action of diabatic processes in a Lagrangian frame by splitting θ and PV into components that are materially conserved and components that are diabatically generated. Since diabatic tracers are subject to advection by the three-dimensional wind field, they are useful tools for the investigation of the interaction of diabatic processes with the atmospheric flow and the impact of diabatic processes on the evolution of the atmosphere. In this contribution, we present a novel integral interpretation of diabatic tracers over suitably defined control volumes, which depend on the weather system under consideration. Using two contrasting extratropical cyclones as examples, it is shown that θ tracers can be used to assess and systematically compare the cross-isentropic mass transport around each cyclone, which is related to the amount and distribution of heat produced during each cyclone's development. PV tracers are related to circulation and area-average isentropic vorticity through the application of Stoke's theorem. Using the impermeability theorem for PV, which states there can be no PV flux across isentropic surfaces, it is also shown that cross-isentropic motion within the control volumes does not directly influence circulation. Instead, the influence of diabatic processes on the circulation crucially depends on the balance between the fluxes along isentropic surfaces of the materially-conserved and diabatically-generated PV components across the lateral boundaries of the control volumes. Finally, the application of the integral interpretation of diabatic tracers for the assessment of model consistency across different model resolutions is discussed.

  13. Galaxy Formation with Self-Consistently Modeled Stars and Massive Black Holes. I: Feedback-Regulated Star Formation and Black Hole Growth

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji-hoon; Wise, John H.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Princeton U., Astrophys. Sci. Dept.; Alvarez, Marcelo A.; /Canadian Inst. Theor. Astrophys.; Abel, Tom; /KIPAC, Menlo Park /Stanford U., Phys. Dept.

    2011-11-04

    There is mounting evidence for the coevolution of galaxies and their embedded massive black holes (MBHs) in a hierarchical structure formation paradigm. To tackle the nonlinear processes of galaxy-MBH interaction, we describe a self-consistent numerical framework which incorporates both galaxies and MBHs. The high-resolution adaptive mesh refinement (AMR) code Enzo is modified to model the formation and feedback of molecular clouds at their characteristic scale of 15.2 pc and the accretion of gas onto an MBH. Two major channels of MBH feedback, radiative feedback (X-ray photons followed through full three-dimensional adaptive ray tracing) and mechanical feedback (bipolar jets resolved in high-resolution AMR), are employed. We investigate the coevolution of a 9.2 x 10{sup 11} M {circle_dot} galactic halo and its 10{sup 5} {circle_dot} M embedded MBH at redshift 3 in a cosmological CDM simulation. The MBH feedback heats the surrounding interstellar medium (ISM) up to 10{sup 6} K through photoionization and Compton heating and locally suppresses star formation in the galactic inner core. The feedback considerably changes the stellar distribution there. This new channel of feedback from a slowly growing MBH is particularly interesting because it is only locally dominant and does not require the heating of gas globally on the disk. The MBH also self-regulates its growth by keeping the surrounding ISM hot for an extended period of time.

  14. A Self-consistent Model for a Full Cycle of Recurrent Novae—Wind Mass-loss Rate and X-Ray Luminosity

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Mariko [Department of Astronomy, Keio University, Hiyoshi, Yokohama 223-8521 (Japan); Saio, Hideyuki [Astronomical Institute, Graduate School of Science, Tohoku University, Sendai, 980-8578 (Japan); Hachisu, Izumi, E-mail: mariko.kato@hc.st.keio.ac.jp [Department of Earth Science and Astronomy, College of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902 (Japan)

    2017-04-01

    An unexpectedly slow evolution in the pre-optical-maximum phase was suggested in the very short recurrence period of nova M31N 2008-12a. To obtain reasonable nova light curves we have improved our calculation method by consistently combining optically thick wind solutions of hydrogen-rich envelopes with white dwarf (WD) structures calculated by a Henyey-type evolution code. The wind mass-loss rate is properly determined with high accuracy. We have calculated light curve models for 1.2 M {sub ⊙} and 1.38 M {sub ⊙} WDs with mass accretion rates corresponding to recurrence periods of 10 yr and 1 yr, respectively. The outburst lasts 590/29 days, in which the pre-optical-maximum phase is 82/16 days, for 1.2/1.38 M {sub ⊙}, respectively. Optically thick winds start at the end of the X-ray flash and cease at the beginning of the supersoft X-ray phase. We also present supersoft X-ray light curves including a prompt X-ray flash and later supersoft X-ray phase.

  15. 'Self-consistent' production of ion conics on return current region auroral field lines - A time-dependent, semi-kinetic model

    Science.gov (United States)

    Brown, David G.; Wilson, Gordon R.; Horwitz, James L.; Gallagher, Dennis L.

    1991-01-01

    We describe initial results from a time-dependent, semi-kinetic model of plasma outflow incorporating wave-particle interactions along current-carrying auroral field lines. Electrostatic waves are generated by the current driven ion cyclotron instability (CDICI), causing perpendicular velocity diffusion of ions plus electron heating via anomalous resistivity when and where the relative drift between electrons and ions exceeds certain critical velocities. Using the local bulk parameters we calculate these critical velocities, and so are able to self-consistently switch on and off the heating of the various particle species. Due to the dependence of these critical velocities on the bulk parameters of the species the heating effects exhibit quite complex spatial and temporal variations. A wide range of ion distribution functions are observed in these simulations, including conics with energies of a few electron volts and 'ring' distributions. The rings are seen to be a natural result of transverse heating and velocity filter effects and do not require coherent acceleration processes. We also observe the formation of a density depletion in hydrogen and enhanced oxygen densities at high altitudes.

  16. Cation solvation with quantum chemical effects modeled by a size-consistent multi-partitioning quantum mechanics/molecular mechanics method.

    Science.gov (United States)

    Watanabe, Hiroshi C; Kubillus, Maximilian; Kubař, Tomáš; Stach, Robert; Mizaikoff, Boris; Ishikita, Hiroshi

    2017-07-21

    In the condensed phase, quantum chemical properties such as many-body effects and intermolecular charge fluctuations are critical determinants of the solvation structure and dynamics. Thus, a quantum mechanical (QM) molecular description is required for both solute and solvent to incorporate these properties. However, it is challenging to conduct molecular dynamics (MD) simulations for condensed systems of sufficient scale when adapting QM potentials. To overcome this problem, we recently developed the size-consistent multi-partitioning (SCMP) quantum mechanics/molecular mechanics (QM/MM) method and realized stable and accurate MD simulations, using the QM potential to a benchmark system. In the present study, as the first application of the SCMP method, we have investigated the structures and dynamics of Na + , K + , and Ca 2+ solutions based on nanosecond-scale sampling, a sampling 100-times longer than that of conventional QM-based samplings. Furthermore, we have evaluated two dynamic properties, the diffusion coefficient and difference spectra, with high statistical certainty. Furthermore the calculation of these properties has not previously been possible within the conventional QM/MM framework. Based on our analysis, we have quantitatively evaluated the quantum chemical solvation effects, which show distinct differences between the cations.

  17. The Rucio Consistency Service

    CERN Document Server

    Serfon, Cedric; The ATLAS collaboration

    2016-01-01

    One of the biggest challenge with Large scale data management system is to ensure the consistency between the global file catalog and what is physically on all storage elements. To tackle this issue, the Rucio software which is used by the ATLAS Distributed Data Management system has been extended to automatically handle lost or unregistered files (aka Dark Data). This system automatically detects these inconsistencies and take actions like recovery or deletion of unneeded files in a central manner. In this talk, we will present this system, explain the internals and give some results.

  18. Elasto-viscoplastic self consistent modeling of the ambient temperature plastic behavior of periclase deformed up to 5.4 GPa

    Science.gov (United States)

    Lin, F.; Hilairet, N.; Raterron, P.; Addad, A.; Immoor, J.; Marquardt, H.; Tomé, C. N.; Miyagi, L.; Merkel, S.

    2017-11-01

    Anisotropy has a crucial effect on the mechanical response of polycrystalline materials. Polycrystal anisotropy is a consequence of single crystal anisotropy and texture (crystallographic preferred orientation) development, which can result from plastic deformation by dislocation glide. The plastic behavior of polycrystals is different under varying hydrostatic pressure conditions, and understanding the effect of hydrostatic pressure on plasticity is of general interest. Moreover, in the case of geological materials, it is useful for understanding material behavior in the deep earth and for the interpretation of seismic data. Periclase is a good material to test because of its simple and stable crystal structure (B1), and it is of interest to geosciences, as (Mg,Fe)O is the second most abundant phase in Earth's lower mantle. In this study, a polycrystalline sintered sample of periclase is deformed at ˜5.4 GPa and ambient temperature, to a total strain of 37% at average strain rates of 2.26 × 10-5/s and 4.30 × 10-5/s. Lattice strains and textures in the polycrystalline sample are recorded using in-situ synchrotron x-ray diffraction and are modeled with Elasto-Viscoplastic Self Consistent (EVPSC) methods. Parameters such as critical resolved shear stress (CRSS) for the various slip systems, strain hardening, initial grain shape, and the strength of the grain-neighborhood interaction are tested in order to optimize the simulation. At the beginning of deformation, a transient maximum occurs in lattice strains, then lattice strains relax to a "steady-state" value, which, we believe, corresponds to the true flow strength of periclase. The "steady state" CRSS of the {" separators="| 110 } ⟨" separators="| 1 1 ¯ 0 ⟩ slip system is 1.2 GPa, while modeling the transient maximum requires a CRSS of 2.2 GPa. Interpretation of the overall experimental data via modeling indicates dominant {" separators="| 110 } ⟨" separators="| 1 1 ¯ 0 ⟩ slip with initial strain

  19. A parameter optimization tool for evaluating the physical consistency of the plot-scale water budget of the integrated eco-hydrological model GEOtop in complex terrain

    Science.gov (United States)

    Bertoldi, Giacomo; Cordano, Emanuele; Brenner, Johannes; Senoner, Samuel; Della Chiesa, Stefano; Niedrist, Georg

    2017-04-01

    regions, since it considers the effect of topography on radiation and water fluxes and integrates a snow module. A new automatic sensitivity and optimization tool based on the Particle Swarm Optimization theory has been developed, available as R package on https://github.com/EURAC-Ecohydro/geotopOptim2. The model, once calibrated for soil and vegetation parameters, predicts the plot-scale temporal SMC dynamics of SMC and ET with a RMSE of about 0.05 m3/m3 and 40 W/m2, respectively. However, the model tends to underestimate ET during summer months over apple orchards. Results show how most sensitive parameters are both soil and canopy structural properties. However, ranking is affected by the choice of the target function and local topographic conditions. In particular, local slope/aspect influences results in stations located over hillslopes, but with marked seasonal differences. Results for locations in the valley floor are strongly controlled by the choice of the bottom water flux boundary condition. The poorer model performances in simulating ET over apple orchards could be explained by a model structural deficiency in representing the stomatal control on vapor pressure deficit for this particular type of vegetation. The results of this sensitivity could be extended to other physically distributed models, and also provide valuable insights for optimizing new experimental designs.

  20. Self-consistent residual dipolar coupling based model-free analysis for the robust determination of nanosecond to microsecond protein dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Lakomek, Nils-Alexander; Walter, Korvin F. A.; Fares, Christophe [Max-Planck Institute for Biophysical Chemistry, Department for NMR-based Structural Biology (Germany); Lange, Oliver F.; Groot, Bert L. de; Grubmueller, Helmut [Max-Planck Institute for Biophysical Chemistry, Department for Theoretical and Computational Biophysics (Germany); Brueschweiler, Rafael [Florida State University, NHFML (United States); Munk, Axel [University of Goettingen, Institut for Mathematical Stochastics (Germany); Becker, Stefan [Max-Planck Institute for Biophysical Chemistry, Department for NMR-based Structural Biology (Germany); Meiler, Jens [Vanderbilt University, Department of Chemistry, Center of Structural Biology (United States); Griesinger, Christian [Max-Planck Institute for Biophysical Chemistry, Department for NMR-based Structural Biology (Germany)], E-mail: cigr@nmr.mpibpc.mpg.de

    2008-07-15

    Residual dipolar couplings (RDCs) provide information about the dynamic average orientation of inter-nuclear vectors and amplitudes of motion up to milliseconds. They complement relaxation methods, especially on a time-scale window that we have called supra-{tau}{sub c} ({tau}{sub c} < supra-{tau}{sub c} < 50 {mu}s). Here we present a robust approach called Self-Consistent RDC-based Model-free analysis (SCRM) that delivers RDC-based order parameters-independent of the details of the structure used for alignment tensor calculation-as well as the dynamic average orientation of the inter-nuclear vectors in the protein structure in a self-consistent manner. For ubiquitin, the SCRM analysis yields an average RDC-derived order parameter of the NH vectors = 0.72 {+-} 0.02 compared to = 0.778 {+-} 0.003 for the Lipari-Szabo order parameters, indicating that the inclusion of the supra-{tau}{sub c} window increases the averaged amplitude of mobility observed in the sub-{tau}{sub c} window by about 34%. For the {beta}-strand spanned by residues Lys48 to Leu50, an alternating pattern of backbone NH RDC order parameter S{sub rdc}{sup 2} (NH) = (0.59, 0.72, 0.59) was extracted. The backbone of Lys48, whose side chain is known to be involved in the poly-ubiquitylation process that leads to protein degradation, is very mobile on the supra-{tau}{sub c} time scale (S{sub rdc}{sup 2} (NH) = 0.59 {+-} 0.03), while it is inconspicuous (S{sub LS}{sup 2} (NH) = 0.82) on the sub-{tau}{sub c} as well as on {mu}s-ms relaxation dispersion time scales. The results of this work differ from previous RDC dynamics studies of ubiquitin in the sense that the results are essentially independent of structural noise providing a much more robust assessment of dynamic effects that underlie the RDC data.

  1. When is holography consistent?

    Directory of Open Access Journals (Sweden)

    Brett McInnes

    2015-09-01

    Full Text Available Holographic duality relates two radically different kinds of theory: one with gravity, one without. The very existence of such an equivalence imposes strong consistency conditions which are, in the nature of the case, hard to satisfy. Recently a particularly deep condition of this kind, relating the minimum of a probe brane action to a gravitational bulk action (in a Euclidean formulation, has been recognized; and the question arises as to the circumstances under which it, and its Lorentzian counterpart, is satisfied. We discuss the fact that there are physically interesting situations in which one or both versions might, in principle, not be satisfied. These arise in two distinct circumstances: first, when the bulk is not an Einstein manifold and, second, in the presence of angular momentum. Focusing on the application of holography to the quark–gluon plasma (of the various forms arising in the early Universe and in heavy-ion collisions, we find that these potential violations never actually occur. This suggests that the consistency condition is a “law of physics” expressing a particular aspect of holography.

  2. Improving the Functionality of Dictionary Definitions for Lexical Sets: The Role of Definitional Templates, Definitional Consistency, Definitional Coherence and the Incorporation of Lexical Conceptual Models

    Directory of Open Access Journals (Sweden)

    Piet Swanepoel

    2011-10-01

    Full Text Available

    ABSTRACT: This article focuses on some of the problems raised by Atkins and Rundell's (2008 approach to the design of lexicographic definitions for members of lexical sets. The questions raised are how to define and identify lexical sets, how lexical conceptual models (LCMs can support definitional consistency and coherence in defining members of lexical sets, and what the ideal content and structure of LCMs could be. Although similarity of meaning is proposed as the defining feature of lexical sets, similarity of meaning is only one dimension of the broader concept of lexical coherence. The argument is presented that numerous conceptual lexical models (e.g. taxonomies, folk models, frames, etc. in fact indicate, justify or explain how lexical items cohere (and thus form sets. In support of Fillmore's (2003 suggestion that definitions of the lexical items of cohering sets should be linked to such explanatory models, additional functionally-orientated arguments are presented for the incorporation of conceptual lexical models in electronic monolingual learners' dictionaries. Numerous resources exist to support the design of LCMs which can improve the functionality of definitions of members of lexical sets. A few examples are discussed of how such resources can be used to design functionally justified LCMs.

    OPSOMMING: Verbetering van die funksionaliteit van woordeboekdefinisies vir leksikale versamelings: Die rol van definisiematryse, definisie-eenvormigheid, definisiesamehang en die inkorporering van leksikale konseptuele modelle. Hierdie artikel fokus op sommige van die probleme wat ter sprake kom deur Atkins en Rundell (2008 se benadering tot die ontwerp van leksikografiese definisies vir lede van leksikale versamelings. Die vrae wat gestel word, is hoe leksikale versamelings gedefinieer en geïdentifiseer moet word, hoe leksikale konseptuele modelle (LKM's definisie-eenvormigheid en-samehang kan ondersteun by die definiëring van lede

  3. Consistency of color representation in smart phones.

    Science.gov (United States)

    Dain, Stephen J; Kwan, Benjamin; Wong, Leslie

    2016-03-01

    One of the barriers to the construction of consistent computer-based color vision tests has been the variety of monitors and computers. Consistency of color on a variety of screens has necessitated calibration of each setup individually. Color vision examination with a carefully controlled display has, as a consequence, been a laboratory rather than a clinical activity. Inevitably, smart phones have become a vehicle for color vision tests. They have the advantage that the processor and screen are associated and there are fewer models of smart phones than permutations of computers and monitors. Colorimetric consistency of display within a model may be a given. It may extend across models from the same manufacturer but is unlikely to extend between manufacturers especially where technologies vary. In this study, we measured the same set of colors in a JPEG file displayed on 11 samples of each of four models of smart phone (iPhone 4s, iPhone5, Samsung Galaxy S3, and Samsung Galaxy S4) using a Photo Research PR-730. The iPhones are white LED backlit LCD and the Samsung are OLEDs. The color gamut varies between models and comparison with sRGB space shows 61%, 85%, 117%, and 110%, respectively. The iPhones differ markedly from the Samsungs and from one another. This indicates that model-specific color lookup tables will be needed. Within each model, the primaries were quite consistent (despite the age of phone varying within each sample). The worst case in each model was the blue primary; the 95th percentile limits in the v' coordinate were ±0.008 for the iPhone 4 and ±0.004 for the other three models. The u'v' variation in white points was ±0.004 for the iPhone4 and ±0.002 for the others, although the spread of white points between models was u'v'±0.007. The differences are essentially the same for primaries at low luminance. The variation of colors intermediate between the primaries (e.g., red-purple, orange) mirror the variation in the primaries. The variation in

  4. A self-consistent model of cosmic-ray fluxes and positron excess: roles of nearby pulsars and a sub-dominant source population

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Jagdish C.; Razzaque, Soebur, E-mail: jjagdish@uj.ac.za, E-mail: srazzaque@uj.ac.za [Department of Physics, University of Johannesburg, P. O. Box 524, Auckland Park 2006 (South Africa)

    2017-09-01

    The cosmic-ray positron flux calculated using the cosmic-ray nuclei interactions in our Galaxy cannot explain observed data above 10 GeV. An excess in the measured positron flux is therefore open to interpretation. Nearby pulsars, located within sub-kiloparsec range of the Solar system, are often invoked as plausible sources contributing to the excess. We show that an additional, sub-dominant population of sources together with the contributions from a few nearby pulsars can explain the latest positron excess data from the Alpha Magnetic Spectrometer (AMS). We simultaneously model, using the DRAGON code, propagation of cosmic-ray proton, Helium, electron and positron and fit their respective flux data. Our fit to the Boron to Carbon ratio data gives a diffusion spectral index of 0.45, which is close to the Kraichnan turbulent spectrum.

  5. Expectation Consistent Approximate Inference

    DEFF Research Database (Denmark)

    Opper, Manfred; Winther, Ole

    2005-01-01

    We propose a novel framework for approximations to intractable probabilistic models which is based on a free energy formulation. The approximation can be understood from replacing an average over the original intractable distribution with a tractable one. It requires two tractable probability...

  6. Theoretical modeling of large molecular systems. Advances in the local self consistent field method for mixed quantum mechanics/molecular mechanics calculations.

    Science.gov (United States)

    Monari, Antonio; Rivail, Jean-Louis; Assfeld, Xavier

    2013-02-19

    Molecular mechanics methods can efficiently compute the macroscopic properties of a large molecular system but cannot represent the electronic changes that occur during a chemical reaction or an electronic transition. Quantum mechanical methods can accurately simulate these processes, but they require considerably greater computational resources. Because electronic changes typically occur in a limited part of the system, such as the solute in a molecular solution or the substrate within the active site of enzymatic reactions, researchers can limit the quantum computation to this part of the system. Researchers take into account the influence of the surroundings by embedding this quantum computation into a calculation of the whole system described at the molecular mechanical level, a strategy known as the mixed quantum mechanics/molecular mechanics (QM/MM) approach. The accuracy of this embedding varies according to the types of interactions included, whether they are purely mechanical or classically electrostatic. This embedding can also introduce the induced polarization of the surroundings. The difficulty in QM/MM calculations comes from the splitting of the system into two parts, which requires severing the chemical bonds that link the quantum mechanical subsystem to the classical subsystem. Typically, researchers replace the quantoclassical atoms, those at the boundary between the subsystems, with a monovalent link atom. For example, researchers might add a hydrogen atom when a C-C bond is cut. This Account describes another approach, the Local Self Consistent Field (LSCF), which was developed in our laboratory. LSCF links the quantum mechanical portion of the molecule to the classical portion using a strictly localized bond orbital extracted from a small model molecule for each bond. In this scenario, the quantoclassical atom has an apparent nuclear charge of +1. To achieve correct bond lengths and force constants, we must take into account the inner shell of

  7. Road and Street Centerlines, StreetLabels-The data set is a text feature consisting of 6329 label points representing street names. It was created to show the names of city and county based streets., Published in 1989, Davis County Government.

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Road and Street Centerlines dataset current as of 1989. StreetLabels-The data set is a text feature consisting of 6329 label points representing street names. It was...

  8. An alternative to the plasma emission model: Particle-in-cell, self-consistent electromagnetic wave emission simulations of solar type III radio bursts

    International Nuclear Information System (INIS)

    Tsiklauri, David

    2011-01-01

    High-resolution (sub-Debye length grid size and 10 000 particle species per cell), 1.5D particle-in-cell, relativistic, fully electromagnetic simulations are used to model electromagnetic wave emission generation in the context of solar type III radio bursts. The model studies generation of electromagnetic waves by a super-thermal, hot beam of electrons injected into a plasma thread that contains uniform longitudinal magnetic field and a parabolic density gradient. In effect, a single magnetic line connecting Sun to Earth is considered, for which five cases are studied. (i) We find that the physical system without a beam is stable and only low amplitude level electromagnetic drift waves (noise) are excited. (ii) The beam injection direction is controlled by setting either longitudinal or oblique electron initial drift speed, i.e., by setting the beam pitch angle (the angle between the beam velocity vector and the direction of background magnetic field). In the case of zero pitch angle, i.e., when v-vector b ·E-vector perpendicular =0, the beam excites only electrostatic, standing waves, oscillating at local plasma frequency, in the beam injection spatial location, and only low level electromagnetic drift wave noise is also generated. (iii) In the case of oblique beam pitch angles, i.e., when v-vector b ·E-vector perpendicular =0, again electrostatic waves with same properties are excited. However, now the beam also generates the electromagnetic waves with the properties commensurate to type III radio bursts. The latter is evidenced by the wavelet analysis of transverse electric field component, which shows that as the beam moves to the regions of lower density and hence lower plasma frequency, frequency of the electromagnetic waves drops accordingly. (iv) When the density gradient is removed, an electron beam with an oblique pitch angle still generates the electromagnetic radiation. However, in the latter case no frequency decrease is seen. (v) Since in most of

  9. Physics Reality Show

    Science.gov (United States)

    Erukhimova, Tatiana

    The attention span of K-12 students is very short; they are used to digesting information in short snippets through social media and TV. To get the students interested in physics, we created the Physics Reality Show: a series of staged short videos with duration no longer than a few minutes. Each video explains and illustrates one physics concept or law through a fast-paced sequence of physics demonstrations and experiments. The cast consists entirely of physics undergraduate students with artistic abilities and substantial experience in showing physics demonstrations at current outreach events run by the department: Physics Shows and Physics & Engineering Festival. Undergraduate students are of almost the same age as their high-school audience. They are in the best position to connect with kids and convey their fascination with physics. The PI and other faculty members who are involved in the outreach advise and coach the cast. They help students in staging the episodes and choosing the most exciting and relevant demonstrations. Supported by the APS mini-outreach Grant.

  10. Spatial Heterodyne Observations of Water (SHOW) vapour in the upper troposphere and lower stratosphere from a high altitude aircraft: Modelling and sensitivity analysis

    Science.gov (United States)

    Langille, J. A.; Letros, D.; Zawada, D.; Bourassa, A.; Degenstein, D.; Solheim, B.

    2018-04-01

    A spatial heterodyne spectrometer (SHS) has been developed to measure the vertical distribution of water vapour in the upper troposphere and the lower stratosphere with a high vertical resolution (∼500 m). The Spatial Heterodyne Observations of Water (SHOW) instrument combines an imaging system with a monolithic field-widened SHS to observe limb scattered sunlight in a vibrational band of water (1363 nm-1366 nm). The instrument has been optimized for observations from NASA's ER-2 aircraft as a proof-of-concept for a future low earth orbit satellite deployment. A robust model has been developed to simulate SHOW ER-2 limb measurements and retrievals. This paper presents the simulation of the SHOW ER-2 limb measurements along a hypothetical flight track and examines the sensitivity of the measurement and retrieval approach. Water vapour fields from an Environment and Climate Change Canada forecast model are used to represent realistic spatial variability along the flight path. High spectral resolution limb scattered radiances are simulated using the SASKTRAN radiative transfer model. It is shown that the SHOW instrument onboard the ER-2 is capable of resolving the water vapour variability in the UTLS from approximately 12 km - 18 km with ±1 ppm accuracy. Vertical resolutions between 500 m and 1 km are feasible. The along track sampling capability of the instrument is also discussed.

  11. Production process reproducibility and product quality consistency of transient gene expression in HEK293 cells with anti-PD1 antibody as the model protein.

    Science.gov (United States)

    Ding, Kai; Han, Lei; Zong, Huifang; Chen, Junsheng; Zhang, Baohong; Zhu, Jianwei

    2017-03-01

    Demonstration of reproducibility and consistency of process and product quality is one of the most crucial issues in using transient gene expression (TGE) technology for biopharmaceutical development. In this study, we challenged the production consistency of TGE by expressing nine batches of recombinant IgG antibody in human embryonic kidney 293 cells to evaluate reproducibility including viable cell density, viability, apoptotic status, and antibody yield in cell culture supernatant. Product quality including isoelectric point, binding affinity, secondary structure, and thermal stability was assessed as well. In addition, major glycan forms of antibody from different batches of production were compared to demonstrate glycosylation consistency. Glycan compositions of the antibody harvested at different time periods were also measured to illustrate N-glycan distribution over the culture time. From the results, it has been demonstrated that different TGE batches are reproducible from lot to lot in overall cell growth, product yield, and product qualities including isoelectric point, binding affinity, secondary structure, and thermal stability. Furthermore, major N-glycan compositions are consistent among different TGE batches and conserved during cell culture time.

  12. Dynamically consistent oil import tariffs

    International Nuclear Information System (INIS)

    Karp, L.; Newbery, D.M.

    1992-01-01

    The standard theory of optimal tariffs considers tariffs on perishable goods produced abroad under static conditions, in which tariffs affect prices only in that period. Oil and other exhaustable resources do not fit this model, for current tariffs affect the amount of oil imported, which will affect the remaining stock and hence its future price. The problem of choosing a dynamically consistent oil import tariff when suppliers are competitive but importers have market power is considered. The open-loop Nash tariff is solved for the standard competitive case in which the oil price is arbitraged, and it was found that the resulting tariff rises at the rate of interest. This tariff was found to have an equilibrium that in general is dynamically inconsistent. Nevertheless, it is shown that necessary and sufficient conditions exist under which the tariff satisfies the weaker condition of time consistency. A dynamically consistent tariff is obtained by assuming that all agents condition their current decisions on the remaining stock of the resource, in contrast to open-loop strategies. For the natural case in which all agents choose their actions simultaneously in each period, the dynamically consistent tariff was characterized, and found to differ markedly from the time-inconsistent open-loop tariff. It was shown that if importers do not have overwhelming market power, then the time path of the world price is insensitive to the ability to commit, as is the level of wealth achieved by the importer. 26 refs., 4 figs

  13. Self-consistent radial sheath

    International Nuclear Information System (INIS)

    Hazeltine, R.D.

    1988-12-01

    The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig

  14. Chemical composition analysis and product consistency tests supporting refinement of the Nepheline Model for the high aluminum Hanford glass composition region

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Mcclane, D. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-01

    In this report, Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated high level waste (HLW) glasses fabricated by Pacific Northwest National Laboratory (PNNL) as part of an ongoing nepheline crystallization study. The results of these analyses will be used to improve the ability to predict crystallization of nepheline as a function of composition and heat treatment for glasses formulated at high alumina concentrations.

  15. Chemical composition analysis and product consistency tests supporting refinement of the Nepheline model for the high aluminum Hanford Glass composition region

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States); Mcclane, D. L. [Savannah River Site (SRS), Aiken, SC (United States)

    2016-02-17

    In this report, SRNL provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated HLW glasses fabricated by Pacific Northwest National Laboratory (PNNL) as part of an ongoing nepheline crystallization study. The results of these analyses will be used to improve the ability to predict crystallization of nepheline as a function of composition and heat treatment for glasses formulated at high alumina concentrations.

  16. A validated age-related normative model for male total testosterone shows increasing variance but no decline after age 40 years.

    Science.gov (United States)

    Kelsey, Thomas W; Li, Lucy Q; Mitchell, Rod T; Whelan, Ashley; Anderson, Richard A; Wallace, W Hamish B

    2014-01-01

    The diagnosis of hypogonadism in human males includes identification of low serum testosterone levels, and hence there is an underlying assumption that normal ranges of testosterone for the healthy population are known for all ages. However, to our knowledge, no such reference model exists in the literature, and hence the availability of an applicable biochemical reference range would be helpful for the clinical assessment of hypogonadal men. In this study, using model selection and validation analysis of data identified and extracted from thirteen studies, we derive and validate a normative model of total testosterone across the lifespan in healthy men. We show that total testosterone peaks [mean (2.5-97.5 percentile)] at 15.4 (7.2-31.1) nmol/L at an average age of 19 years, and falls in the average case [mean (2.5-97.5 percentile)] to 13.0 (6.6-25.3) nmol/L by age 40 years, but we find no evidence for a further fall in mean total testosterone with increasing age through to old age. However we do show that there is an increased variation in total testosterone levels with advancing age after age 40 years. This model provides the age related reference ranges needed to support research and clinical decision making in males who have symptoms that may be due to hypogonadism.

  17. Gastrointestinal Simulation Model TWIN-SHIME Shows Differences between Human Urolithin-Metabotypes in Gut Microbiota Composition, Pomegranate Polyphenol Metabolism, and Transport along the Intestinal Tract.

    Science.gov (United States)

    García-Villalba, Rocío; Vissenaekens, Hanne; Pitart, Judit; Romo-Vaquero, María; Espín, Juan C; Grootaert, Charlotte; Selma, María V; Raes, Katleen; Smagghe, Guy; Possemiers, Sam; Van Camp, John; Tomas-Barberan, Francisco A

    2017-07-12

    A TWIN-SHIME system was used to compare the metabolism of pomegranate polyphenols by the gut microbiota from two individuals with different urolithin metabotypes. Gut microbiota, ellagitannin metabolism, short-chain fatty acids (SCFA), transport of metabolites, and phase II metabolism using Caco-2 cells were explored. The simulation reproduced the in vivo metabolic profiles for each metabotype. The study shows for the first time that microbial composition, metabolism of ellagitannins, and SCFA differ between metabotypes and along the large intestine. The assay also showed that pomegranate phenolics preserved intestinal cell integrity. Pomegranate polyphenols enhanced urolithin and propionate production, as well as Akkermansia and Gordonibacter prevalence with the highest effect in the descending colon. The system provides an insight into the mechanisms of pomegranate polyphenol gut microbiota metabolism and absorption through intestinal cells. The results obtained by the combined SHIME/Caco-2 cell system are consistent with previous human and animal studies and show that although urolithin metabolites are present along the gastrointestinal tract due to enterohepatic circulation, they are predominantly produced in the distal colon region.

  18. A Model of Compound Heterozygous, Loss-of-Function Alleles Is Broadly Consistent with Observations from Complex-Disease GWAS Datasets.

    Directory of Open Access Journals (Sweden)

    Jaleal S Sanjak

    2017-01-01

    Full Text Available The genetic component of complex disease risk in humans remains largely unexplained. A corollary is that the allelic spectrum of genetic variants contributing to complex disease risk is unknown. Theoretical models that relate population genetic processes to the maintenance of genetic variation for quantitative traits may suggest profitable avenues for future experimental design. Here we use forward simulation to model a genomic region evolving under a balance between recurrent deleterious mutation and Gaussian stabilizing selection. We consider multiple genetic and demographic models, and several different methods for identifying genomic regions harboring variants associated with complex disease risk. We demonstrate that the model of gene action, relating genotype to phenotype, has a qualitative effect on several relevant aspects of the population genetic architecture of a complex trait. In particular, the genetic model impacts genetic variance component partitioning across the allele frequency spectrum and the power of statistical tests. Models with partial recessivity closely match the minor allele frequency distribution of significant hits from empirical genome-wide association studies without requiring homozygous effect sizes to be small. We highlight a particular gene-based model of incomplete recessivity that is appealing from first principles. Under that model, deleterious mutations in a genomic region partially fail to complement one another. This model of gene-based recessivity predicts the empirically observed inconsistency between twin and SNP based estimated of dominance heritability. Furthermore, this model predicts considerable levels of unexplained variance associated with intralocus epistasis. Our results suggest a need for improved statistical tools for region based genetic association and heritability estimation.

  19. Consistency relation for cosmic magnetic fields

    Science.gov (United States)

    Jain, Rajeev Kumar; Sloth, Martin S.

    2012-12-01

    If cosmic magnetic fields are indeed produced during inflation, they are likely to be correlated with the scalar metric perturbations that are responsible for the cosmic microwave background anisotropies and large scale structure. Within an archetypical model of inflationary magnetogenesis, we show that there exists a new simple consistency relation for the non-Gaussian cross correlation function of the scalar metric perturbation with two powers of the magnetic field in the squeezed limit where the momentum of the metric perturbation vanishes. We emphasize that such a consistency relation turns out to be extremely useful to test some recent calculations in the literature. Apart from primordial non-Gaussianity induced by the curvature perturbations, such a cross correlation might provide a new observational probe of inflation and can in principle reveal the primordial nature of cosmic magnetic fields.

  20. On self-consistent ray-tracing and Fokker-Planck modeling of the hard X-ray emission during lower-hybrid current driven in Tokamaks

    International Nuclear Information System (INIS)

    Bizarro, J.P.; Peysson, Y.; Bonoli, P.T.; Carrasco, J.; Dudok de Wit, T.; Fuchs, V.; Hoang, G.T.; Litaudon, X.; Moreau, D.; Pocheau, C.; Shkarofsky, I.P.

    1993-04-01

    A detailed investigation is presented on the ability of combined ray-tracing and Fokker-Planck calculations to predict the hard x-ray (HXR) emission during lower-hybrid (LH) current drive in tokamaks when toroidally induced-ray-stochasticity is important. A large number of rays is used and the electron distribution function is obtained by self-consistently iterating the appropriate LH power deposition and Fokker-Planck calculations. Most of the experimentally observed features of the HXR emission are correctly predicted. It is found that corrections due to radial diffusion of suprathermal electrons and to radiation scattering by the inner wall can be significant

  1. Evaluation of the Consistency among In Situ and Remote Sensing Measurements of CO2 over North America using the CarbonTracker-Lagrange Regional Inverse Modeling Framework

    Science.gov (United States)

    Andrews, A. E.; Trudeau, M.; Hu, L.; Thoning, K. W.; Shiga, Y. P.; Michalak, A. M.; Benmergui, J. S.; Mountain, M. E.; Nehrkorn, T.; O'Dell, C.; Jacobson, A. R.; Miller, J.; Sweeney, C.; Chen, H.; Ploeger, F.; Tans, P. P.

    2017-12-01

    CarbonTracker-Lagrange (CT-L) is a regional inverse modeling system for estimating CO2 fluxes with rigorous uncertainty quantification. CT-L uses footprints from the Stochastic Time-Inverted Lagrangian Transport (STILT) model driven by high-resolution (10 to 30 km) meteorological fields from the Weather Research and Forecasting (WRF) model. We have computed a library of footprints corresponding to in situ and remote sensing measurements of CO2 over North America for 2007-2015. GOSAT and OCO-2 XCO2 retrievals are simulated using a suite of CT-L terrestrial ecosystem flux estimates that have been optimized with respect to in situ atmospheric CO2 measurements along with fossil fuel fluxes from emissions inventories. A vertical profile of STILT-WRF footprints was constructed corresponding to each simulated satellite retrieval, and CO2 profiles are generated by convolving the footprints with fluxes and attaching initial values advected from the domain boundaries. The stratospheric contribution to XCO2 has been estimated using 4-dimensional CO2 fields from the NOAA CarbonTracker model (version CT2016) and from the Chemical Lagrangian Model of the Stratosphere (CLaMS), after scaling the model fields to match data from the NOAA AirCore surface-to-stratosphere air sampling system. Tropospheric lateral boundary conditions are from CT2016 and from an empirical boundary value product derived from aircraft and marine boundary layer data. The averaging kernel and a priori CO2 profile are taken into account for direct comparisons with retrievals. We have focused on North America due to the relatively dense in situ measurements available with the aim of developing strategies for combined assimilation of in situ and remote sensing data. We will consider the extent to which interannual variability in terrestrial fluxes is manifest in the real and simulated satellite retrievals, and we will investigate possible systematic biases in the satellite retrievals and in the model.

  2. Consistent interpretations of quantum mechanics

    International Nuclear Information System (INIS)

    Omnes, R.

    1992-01-01

    Within the last decade, significant progress has been made towards a consistent and complete reformulation of the Copenhagen interpretation (an interpretation consisting in a formulation of the experimental aspects of physics in terms of the basic formalism; it is consistent if free from internal contradiction and complete if it provides precise predictions for all experiments). The main steps involved decoherence (the transition from linear superpositions of macroscopic states to a mixing), Griffiths histories describing the evolution of quantum properties, a convenient logical structure for dealing with histories, and also some progress in semiclassical physics, which was made possible by new methods. The main outcome is a theory of phenomena, viz., the classically meaningful properties of a macroscopic system. It shows in particular how and when determinism is valid. This theory can be used to give a deductive form to measurement theory, which now covers some cases that were initially devised as counterexamples against the Copenhagen interpretation. These theories are described, together with their applications to some key experiments and some of their consequences concerning epistemology

  3. A Multiple siRNA-Based Anti-HIV/SHIV Microbicide Shows Protection in Both In Vitro and In Vivo Models.

    Directory of Open Access Journals (Sweden)

    Sandhya Boyapalle

    Full Text Available Human immunodeficiency virus (HIV types 1 and 2 (HIV-1 and HIV-2 are the etiologic agents of AIDS. Most HIV-1 infected individuals worldwide are women, who acquire HIV infections during sexual contact. Blocking HIV mucosal transmission and local spread in the female lower genital tract is important in preventing infection and ultimately eliminating the pandemic. Microbicides work by destroying the microbes or preventing them from establishing an infection. Thus, a number of different types of microbicides are under investigation, however, the lack of their solubility and bioavailability, and toxicity has been major hurdles. Herein, we report the development of multifunctional chitosan-lipid nanocomplexes that can effectively deliver plasmids encoding siRNA(s as microbicides without adverse effects and provide significant protection against HIV in both in vitro and in vivo models. Chitosan or chitosan-lipid (chlipid was complexed with a cocktail of plasmids encoding HIV-1-specific siRNAs (psiRNAs and evaluated for their efficacy in HEK-293 cells, PBMCs derived from nonhuman primates, 3-dimensional human vaginal ectocervical tissue (3D-VEC model and also in non-human primate model. Moreover, prophylactic administration of the chlipid to deliver a psiRNA cocktail intravaginally with a cream formulation in a non-human primate model showed substantial reduction of SHIV (simian/human immunodeficiency virus SF162 viral titers. Taken together, these studies demonstrate the potential of chlipid-siRNA nanocomplexes as a potential genetic microbicide against HIV infections.

  4. Deformation behavior of Mg-8.5wt.%Al alloy under reverse loading investigated by in-situ neutron diffraction and elastic viscoplastic self-consistent modeling

    International Nuclear Information System (INIS)

    Wang, H.; Lee, S.Y.; Gharghouri, M.A.; Wu, P.D.; Yoon, S.G.

    2016-01-01

    The EVPSC-TDT model for polycrystal plasticity and in-situ neutron diffraction have been used to investigate the behavior of a Mg-8.5wt.%Al alloy with two starting textures: 1) a typical extrusion texture in which a majority of the grains are oriented favorably for extension twinning via compression perpendicular to the basal pole, and 2) a modified texture in which extension twinning can be activated via tension parallel to the basal pole in a majority of the grains. Using a small number of adjustable parameters, and only two macroscopic tensile stress–strain curves for calibration, the model is able to capture, quantitatively, the trends in multiple data sets, including grain-level elastic lattice strains, and diffraction peak intensity changes due to lattice re-orientation associated with twinning. For twinning, the model assumes a polar critical resolved shear stress activation criterion and assigns the stress and hardening of the parent crystal to a newly formed twin. The model allows twinning to be driven either by the stress in the parent crystal (matrix reduction), in which case all of the twin transformation strain is assigned to the matrix, or by the stress in the twin (twin propagation), in which case all of the twin transformation strain is assigned to the twin. A detailed comparison between the model predictions and the neutron diffraction data reveals that assigning all of the twin transformation strain either to the matrix or to the twin is too one-sided, leading to excessive relaxation and hardening effects. A more equitable partitioning of the twin transformation strain is necessary. It is suggested that the stress and hardening assigned to a newly formed twin is of less importance to the performance of the model than the partitioning of the twin transformation strain.

  5. Modeling shows that the NS5A inhibitor daclatasvir has two modes of action and yields a shorter estimate of the hepatitis C virus half-life.

    Science.gov (United States)

    Guedj, Jeremie; Dahari, Harel; Rong, Libin; Sansone, Natasha D; Nettles, Richard E; Cotler, Scott J; Layden, Thomas J; Uprichard, Susan L; Perelson, Alan S

    2013-03-05

    The nonstructural 5A (NS5A) protein is a target for drug development against hepatitis C virus (HCV). Interestingly, the NS5A inhibitor daclatasvir (BMS-790052) caused a decrease in serum HCV RNA levels by about two orders of magnitude within 6 h of administration. However, NS5A has no known enzymatic functions, making it difficult to understand daclatasvir's mode of action (MOA) and to estimate its antiviral effectiveness. Modeling viral kinetics during therapy has provided important insights into the MOA and effectiveness of a variety of anti-HCV agents. Here, we show that understanding the effects of daclatasvir in vivo requires a multiscale model that incorporates drug effects on the HCV intracellular lifecycle, and we validated this approach with in vitro HCV infection experiments. The model predicts that daclatasvir efficiently blocks two distinct stages of the viral lifecycle, namely viral RNA synthesis and virion assembly/secretion with mean effectiveness of 99% and 99.8%, respectively, and yields a more precise estimate of the serum HCV half-life, 45 min, i.e., around four times shorter than previous estimates. Intracellular HCV RNA in HCV-infected cells treated with daclatasvir and the HCV polymerase inhibitor NM107 showed a similar pattern of decline. However, daclatasvir treatment led to an immediate and rapid decline of extracellular HCV titers compared to a delayed (6-9 h) and slower decline with NM107, confirming an effect of daclatasvir on both viral replication and assembly/secretion. The multiscale modeling approach, validated with in vitro kinetic experiments, brings a unique conceptual framework for understanding the mechanism of action of a variety of agents in development for the treatment of HCV.

  6. Consistency of priorities for quality improvement for nursing homes in Italy and Canada: A comparison of optimization models of resident satisfaction.

    Science.gov (United States)

    Barsanti, Sara; Walker, Kevin; Seghieri, Chiara; Rosa, Antonella; Wodchis, Walter P

    2017-08-01

    The paper seeks to identify aspects of care that may be easily modified to yield a desired level of improvement in residents' overall satisfaction with nursing homes, comparing data across Canada and Italy. Using a structured questionnaire, 681 and 1116 nursing home residents were surveyed in Ontario in 2009 and in Tuscany in 2012, respectively. Fourteen items were common to the surveys, including willingness to recommend (WTR), which was used as the dependent variable and measure of global satisfaction. The other analogous items were entered as covariates in ordinal logistic regression models predicting residents' WTR in each jurisdiction separately. Regression coefficients were then incorporated into a constrained nonlinear optimization problem selecting the most efficient combination of predictors necessary to increase WTR by as much as 15%. Staff-related aspects of care were selected first in the optimization models of each jurisdiction. In Ontario, to improve WTR the primary focus should be on staff relationships with residents, while in Tuscany it was the technical skill and knowledge of staff that was selected first by the optimization model. Different optimization solutions might mean that the strategies required to improve global satisfaction in one jurisdiction could be different than those for the other jurisdictions. The optimization model employed provides a novel solution for prioritizing areas of focus for quality improvement for nursing homes. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Formation of Supermassive Black Holes in Galactic Bulges: A Rotating Collapse Model Consistent with the M(sub BH-sigma) Relation

    Science.gov (United States)

    Adams, Fred C.; Graff, David S.; Mbonye, Manasse; Richstone, Douglas O.

    2003-01-01

    Motivated by the observed correlation between black hole masses M(sub BH) and the velocity dispersion sigma of host galaxies, we develop a theoretical model of black hole formation in galactic bulges (this paper generalizes an earlier ApJ Letter). The model assumes an initial state specified by a uniform rotation rate OMEGA and a density distribution of the form rho = a(sup 2)(sub eff)per2piGR(sup 2)(so that a(sub eff)is an effective transport speed). The black hole mass is determined when the centrifugal radius of the collapse flow exceeds the capture radius of the central black hole (for Schwarzschild geometry). This model reproduces the observed correlation between the estimated black hole masses and the velocity dispersions of galactic bulges, i.e., M(sub BH) approximately equal to 10(sup 8) solar mass(sigma per 200 kilometers per second)(sup 4) where sigma = the square root of 2a(sub eff). To obtain this normalization, the rotation rate OMEGA approximately equal to 2 x 10(exp -15) rad per second. The model also defines a bulge mass scale M(sub B). If we identify the scale M(sub B) with the bulge mass, the model determines the ratio mu(sub B) of black hole mass to the host mass: mu(sub B) approximately equal to 0.0024(sigma per 200 kilometer per second), again in reasonable agreement with observed values. In this scenario, supermassive black holes form quickly (in approximately 10(exp 5) yr) and are born rapidly rotating (with a per M approximately 0.9). This paper also shown how these results depend on the assumed initial conditions; the most important quantity is the initial distribution of specific angular momentum in the precollapse state.

  8. An Algebraic Model for the Pion's Valence-Quark GPD: A Probe for a Consistent Extension Beyond DGLAP Region Via Radon Transform Inversion

    Science.gov (United States)

    Chouika, Nabil; Mezrag, Cédric; Moutarde, Hervé; Rodríguez-Quintero, José

    2017-07-01

    We briefly report on a recent computation, with the help of a fruitful algebraic model, sketching the pion valence dressed-quark generalized parton distribution. Then, preliminary, we introduce on a sensible procedure to get reliable results in both Dokshitzer-Gribov-Lipatov-Altarelli-Parisi and Efremov-Radyushkin-Brodsky-Lepage kinematical regions, grounded on the GPD overlap representation and its parametrization of a Radon transform of the so-called double distribution.

  9. Self-consistent mapping of the ab initio calculations to the multi-orbital p- d model: Magnetism in α-FeSi2 films as the effect of the local environment

    Science.gov (United States)

    Zhandun, V.; Zamkova, N.; Ovchinnikov, S.; Sandalov, I.

    2017-11-01

    To accurately translate the results obtained within density functional theory (DFT) to the language of many-body theory we suggest and test the following approach: the parameters of the formulated model are to be found from the requirement that the model self-consistent electron density and density of electron states are as close as possible to the ones found from the DFT-based calculations. The investigation of the phase diagram of the model allows us to find the critical regions in magnetic properties. Then the behavior of the real system in these regions is checked by the ab initio calculations. As an example, we studied the physics of magnetic moment (MM) formation due to substitutions of Si by Fe-atoms or vice versa in the otherwise non-magnetic alloy α-FeSi2. We find that the MM formation is essentially controlled by the interaction of Fe atoms with its next nearest atoms (NNN) and by their particular arrangement. The latter may result in different magnetic states at the same concentrations of constituents. Moreover, one of arrangements produces the counterintuitive result: a ferromagnetism arises due to an increase in Si concentration in Fe1-xSi2+ x ordered alloy. The existing phenomenological models associate the destruction of magnetic moment only with the number of Fe-Si nearest neighbors. The presented results show that the crucial role in MM formation is played by the particular local NNN environment of the metal atom in the transition metal-metalloid alloy.

  10. Self-consistent mapping of the ab initio calculations to the multi-orbital p-d-model: Magnetism in α-FeSi2 films as effect of local environment

    Science.gov (United States)

    Zhandun, V.; Zamkova, N.; Ovchinnikov, S.; Sandalov, I.

    2017-11-01

    To accurately translate the results obtained within density functional theory (DFT) to the language of many-body theory we suggest and test the following approach: the parameters of the formulated model are to be found from the requirement that the model self-consistent electron density and density of electron states are as close as possible to the ones found from the DFT-based calculations. The investigation of the phase diagram of the model allows us to find the critical regions in magnetic properties. Then the behaviour of the real system in these regions is checked by the ab initio calculations. As an example we studied the physics of magnetic moment (MM) formation due to substitutions of Si by Fe-atoms or vice versa in the otherwise non-magnetic alloy α-FeSi2. We find that the MM formation is essentially controlled by the interaction of Fe atoms with its next nearest atoms (NNN) and by their particular arrangement. The latter may result in different magnetic states at the same concentrations of constituents. Moreover, one of arrangements produces the counter-intuitive result: a ferromagnetism arises due to an increase of Si concentration in Fe1-x Si2+x ordered alloy. The existing phenomenological models associate the destruction of magnetic moment only with the number of Fe-Si nearest neighbors. The presented results show that the crucial role in MM formation is played by the particular local NNN environment of the metal atom in the transition metal-metalloid alloy.

  11. Macrophage inflammatory protein-1α shows predictive value as a risk marker for subjects and sites vulnerable to bone loss in a longitudinal model of aggressive periodontitis.

    Directory of Open Access Journals (Sweden)

    Daniel H Fine

    Full Text Available Improved diagnostics remains a fundamental goal of biomedical research. This study was designed to assess cytokine biomarkers that could predict bone loss (BL in localized aggressive periodontitis. 2,058 adolescents were screened. Two groups of 50 periodontally healthy adolescents were enrolled in the longitudinal study. One group had Aggregatibacter actinomycetemcomitans (Aa, the putative pathogen, while the matched cohort did not. Cytokine levels were assessed in saliva and gingival crevicular fluid (GCF. Participants were sampled, examined, and radiographed every 6 months for 2-3 years. Disease was defined as radiographic evidence of BL. Saliva and GCF was collected at each visit, frozen, and then tested retrospectively after detection of BL. Sixteen subjects with Aa developed BL. Saliva from Aa-positive and Aa-negative healthy subjects was compared to subjects who developed BL. GCF was collected from 16 subjects with BL and from another 38 subjects who remained healthy. GCF from BL sites in the 16 subjects was compared to healthy sites in these same subjects and to healthy sites in subjects who remained healthy. Results showed that cytokines in saliva associated with acute inflammation were elevated in subjects who developed BL (i.e., MIP-1α MIP-1β IL-α, IL-1β and IL-8; p<0.01. MIP-1α was elevated 13-fold, 6 months prior to BL. When MIP-1α levels were set at 40 pg/ml, 98% of healthy sites were below that level (Specificity; whereas, 93% of sites with BL were higher (Sensitivity, with comparable Predictive Values of 98%; p<0.0001; 95% C.I. = 42.5-52.7. MIP-1α consistently showed elevated levels as a biomarker for BL in both saliva and GCF, 6 months prior to BL. MIP-1α continues to demonstrate its strong candidacy as a diagnostic biomarker for both subject and site vulnerability to BL.

  12. Synthesis, Modelling, and Anticonvulsant Studies of New Quinazolines Showing Three Highly Active Compounds with Low Toxicity and High Affinity to the GABA-A Receptor

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    Mohamed F. Zayed

    2017-01-01

    Full Text Available Some novel fluorinated quinazolines (5a–j were designed and synthesized to be evaluated for their anticonvulsant activity and their neurotoxicity. Structures of all newly synthesized compounds were confirmed by their infrared (IR, mass spectrometry (MS spectra, 1H nuclear magnetic resonance (NMR, 13C-NMR, and elemental analysis (CHN. The anticonvulsant activity was evaluated by a subcutaneous pentylenetetrazole (scPTZ test and maximal electroshock (MES-induced seizure test, while neurotoxicity was evaluated by a rotorod test. The molecular docking was performed for all newly-synthesized compounds to assess their binding affinities to the GABA-A receptor in order to rationalize their anticonvulsant activities in a qualitative way. The data obtained from the molecular modeling was correlated with that obtained from the biological screening. These data showed considerable anticonvulsant activity for all newly-synthesized compounds. Compounds 5b, 5c, and 5d showed the highest binding affinities toward the GABA-A receptor, along with the highest anticonvulsant activities in experimental mice. These compounds also showed low neurotoxicity and low toxicity in the median lethal dose test compared to the reference drugs. A GABA enzymatic assay was performed for these highly active compounds to confirm the obtained results and explain the possible mechanism for anticonvulsant action. The most active compounds might be used as leads for future modification and optimization.

  13. RETADD-II: a long-range atmospheric trajectory model with consistent treatment of deposition loss and species growth and decay

    International Nuclear Information System (INIS)

    Murphy, B.D.; Ohr, S.Y.; Begovich, C.L.

    1984-08-01

    A versatile model is described which estimates long-range atmospheric dispersion based on plume trajectories. This model allows the treatment of the dispersal from a source at an arbitrary height while taking account of plume depletion by dry and wet deposition together with the decay of material to successor species. The plume depletion, decay and growth equations are solved in an efficient manner which can accommodate up to eight pollutants (i.e., a parent and seven serial decay products). The code is particularly suitable for applications involving radioactive chain decay or for cases involving chemical species with successor decay products. Arbitrary emission rates can be specified for the members of the chain or, as is commonly the case, a sole emission rate can be specified for the first member. The code uses readily available upper-air wind data for the North American continent and it is therefore intended for the estimation of regional or continental scale dispersion patterns. This code is one of a group of codes, the Computerized Radiological Risk Investigation System (Baes and Miller, 1981), designed to simulate the transport of radionuclides through environmental pathways. 24 references, 5 figures

  14. First-order metal-insulator transitions in the extended Hubbard model due to self-consistent screening of the effective interaction

    Science.gov (United States)

    Schüler, M.; van Loon, E. G. C. P.; Katsnelson, M. I.; Wehling, T. O.

    2018-04-01

    While the Hubbard model is the standard model to study Mott metal-insulator transitions, it is still unclear to what extent it can describe metal-insulator transitions in real solids, where nonlocal Coulomb interactions are always present. By using a variational principle, we clarify this issue for short- and long-range nonlocal Coulomb interactions for half-filled systems on bipartite lattices. We find that repulsive nonlocal interactions generally stabilize the Fermi-liquid regime. The metal-insulator phase boundary is shifted to larger interaction strengths to leading order linearly with nonlocal interactions. Importantly, nonlocal interactions can raise the order of the metal-insulator transition. We present a detailed analysis of how the dimension and geometry of the lattice as well as the temperature determine the critical nonlocal interaction leading to a first-order transition: for systems in more than two dimensions with nonzero density of states at the Fermi energy the critical nonlocal interaction is arbitrarily small; otherwise, it is finite.

  15. Maintaining consistency in distributed systems

    Science.gov (United States)

    Birman, Kenneth P.

    1991-01-01

    In systems designed as assemblies of independently developed components, concurrent access to data or data structures normally arises within individual programs, and is controlled using mutual exclusion constructs, such as semaphores and monitors. Where data is persistent and/or sets of operation are related to one another, transactions or linearizability may be more appropriate. Systems that incorporate cooperative styles of distributed execution often replicate or distribute data within groups of components. In these cases, group oriented consistency properties must be maintained, and tools based on the virtual synchrony execution model greatly simplify the task confronting an application developer. All three styles of distributed computing are likely to be seen in future systems - often, within the same application. This leads us to propose an integrated approach that permits applications that use virtual synchrony with concurrent objects that respect a linearizability constraint, and vice versa. Transactional subsystems are treated as a special case of linearizability.

  16. The circumstellar disc of FS Tau B - a self-consistent model based on observations in the mid-infrared with NACO

    Science.gov (United States)

    Kirchschlager, Florian; Wolf, Sebastian; Madlener, David

    2016-10-01

    Protoplanetary discs are a byproduct of the star formation process. In the dense mid-plane of these discs, planetesimals and planets are expected to form. The first step in planet formation is the growth of dust particles from submicrometre-sized grains to macroscopic mm-sized aggregates. The grain growth is accompanied by radial drift and vertical segregation of the particles within the disc. To understand this essential evolutionary step, spatially resolved multi-wavelength observations as well as photometric data are necessary which reflect the properties of both disc and dust. We present the first spatially resolved image obtained with NACO at the VLT in the Lp band of the near edge-on protoplanetary disc FS Tau B. Based on this new image, a previously published Hubble image in H band and the spectral energy distribution from optical to millimetre wavelengths, we derive constraints on the spatial dust distribution and the progress of grain growth. For this purpose we perform a disc modelling using the radiative transfer code MC3D. Radial drift and vertical sedimentation of the dust are not considered. We find a best-fitting model which features a disc extending from 2 au to several hundreds au with a moderately decreasing surface density and Mdisc = 2.8 × 10-2 M⊙. The inclination amounts to I = 80°. Our findings indicate that substantial dust grain growth has taken place and that grains of a size equal to or larger than 1 mm are present in the disc. In conclusion, the parameters describing the vertical density distribution are better constrained than those describing the radial disc structure.

  17. A Consistent Orally-Infected Hamster Model for Enterovirus A71 Encephalomyelitis Demonstrates Squamous Lesions in the Paws, Skin and Oral Cavity Reminiscent of Hand-Foot-and-Mouth Disease.

    Directory of Open Access Journals (Sweden)

    Win Kyaw Phyu

    Full Text Available Enterovirus A71 (EV-A71 causes self-limiting, hand-foot-and-mouth disease (HFMD that may rarely be complicated by encephalomyelitis. Person-to-person transmission is usually by fecal-oral or oral-oral routes. To study viral replication sites in the oral cavity and other tissues, and to gain further insights into virus shedding and neuropathogenesis, we developed a consistent, orally-infected, 2-week-old hamster model of HFMD and EV-A71 encephalomyelitis. Tissues from orally-infected, 2-week-old hamsters were studied by light microscopy, immunohistochemistry and in situ hybridization to detect viral antigens and RNA, respectively, and by virus titration. Hamsters developed the disease and died after 4-8 days post infection; LD50 was 25 CCID50. Macroscopic cutaneous lesions around the oral cavity and paws were observed. Squamous epithelium in the lip, oral cavity, paw, skin, and esophagus, showed multiple small inflammatory foci around squamous cells that demonstrated viral antigens/RNA. Neurons (brainstem, spinal cord, sensory ganglia, acinar cells (salivary gland, lacrimal gland, lymphoid cells (lymph node, spleen, and muscle fibres (skeletal, cardiac and smooth muscles, liver and gastric epithelium also showed varying amounts of viral antigens/RNA. Intestinal epithelium, Peyer's patches, thymus, pancreas, lung and kidney were negative. Virus was isolated from oral washes, feces, brain, spinal cord, skeletal muscle, serum, and other tissues. Our animal model should be useful to study squamous epitheliotropism, neuropathogenesis, oral/fecal shedding in EV-A71 infection, person-to-person transmission, and to test anti-viral drugs and vaccines.

  18. A Consistent Orally-Infected Hamster Model for Enterovirus A71 Encephalomyelitis Demonstrates Squamous Lesions in the Paws, Skin and Oral Cavity Reminiscent of Hand-Foot-and-Mouth Disease.

    Science.gov (United States)

    Phyu, Win Kyaw; Ong, Kien Chai; Wong, Kum Thong

    2016-01-01

    Enterovirus A71 (EV-A71) causes self-limiting, hand-foot-and-mouth disease (HFMD) that may rarely be complicated by encephalomyelitis. Person-to-person transmission is usually by fecal-oral or oral-oral routes. To study viral replication sites in the oral cavity and other tissues, and to gain further insights into virus shedding and neuropathogenesis, we developed a consistent, orally-infected, 2-week-old hamster model of HFMD and EV-A71 encephalomyelitis. Tissues from orally-infected, 2-week-old hamsters were studied by light microscopy, immunohistochemistry and in situ hybridization to detect viral antigens and RNA, respectively, and by virus titration. Hamsters developed the disease and died after 4-8 days post infection; LD50 was 25 CCID50. Macroscopic cutaneous lesions around the oral cavity and paws were observed. Squamous epithelium in the lip, oral cavity, paw, skin, and esophagus, showed multiple small inflammatory foci around squamous cells that demonstrated viral antigens/RNA. Neurons (brainstem, spinal cord, sensory ganglia), acinar cells (salivary gland, lacrimal gland), lymphoid cells (lymph node, spleen), and muscle fibres (skeletal, cardiac and smooth muscles), liver and gastric epithelium also showed varying amounts of viral antigens/RNA. Intestinal epithelium, Peyer's patches, thymus, pancreas, lung and kidney were negative. Virus was isolated from oral washes, feces, brain, spinal cord, skeletal muscle, serum, and other tissues. Our animal model should be useful to study squamous epitheliotropism, neuropathogenesis, oral/fecal shedding in EV-A71 infection, person-to-person transmission, and to test anti-viral drugs and vaccines.

  19. Site-directed mutagenesis and molecular modelling studies show the role of Asp82 and cysteines in rat acylase 1, a member of the M20 family

    International Nuclear Information System (INIS)

    Herga, Sameh; Brutus, Alexandre; Vitale, Rosa Maria; Miche, Helene; Perrier, Josette; Puigserver, Antoine; Scaloni, Andrea; Giardina, Thierry

    2005-01-01

    Acylase 1 from rat kidney catalyzes the hydrolysis of acyl-amino acids. Sequence alignment has shown that this enzyme belongs to the metalloprotein family M20. Site-directed mutagenesis experiments led to the identification of one functionally important amino acid residue located near one of the zinc coordinating residues, which play a critical role in the enzymatic activity. The D82N- and D82E-substituted forms showed no significant activity and very low activity, respectively, along with a loss of zinc coordination. Molecular modelling investigations indicated a putative role of D82 in ensuring a proper protonation of catalytic histidine. In addition, none of the five cysteine residues present in the rat kidney acylase 1 sequence seemed involved in the catalytic process: the loss of activity induced by the C294A substitution was probably due to a conformational change in the 3D structure

  20. The BACHD Rat Model of Huntington Disease Shows Signs of Fronto-Striatal Dysfunction in Two Operant Conditioning Tests of Short-Term Memory.

    Science.gov (United States)

    Clemensson, Erik Karl Håkan; Clemensson, Laura Emily; Riess, Olaf; Nguyen, Huu Phuc

    2017-01-01

    The BACHD rat is a recently developed transgenic animal model of Huntington disease, a progressive neurodegenerative disorder characterized by extensive loss of striatal neurons. Cognitive impairments are common among patients, and characterization of similar deficits in animal models of the disease is therefore of interest. The present study assessed the BACHD rats' performance in the delayed alternation and the delayed non-matching to position test, two Skinner box-based tests of short-term memory function. The transgenic rats showed impaired performance in both tests, indicating general problems with handling basic aspects of the tests, while short-term memory appeared to be intact. Similar phenotypes have been found in rats with fronto-striatal lesions, suggesting that Huntington disease-related neuropathology might be present in the BACHD rats. Further analyses indicated that the performance deficit in the delayed alternation test might be due to impaired inhibitory control, which has also been implicated in Huntington disease patients. The study ultimately suggests that the BACHD rats might suffer from neuropathology and cognitive impairments reminiscent of those of Huntington disease patients.

  1. The BACHD Rat Model of Huntington Disease Shows Signs of Fronto-Striatal Dysfunction in Two Operant Conditioning Tests of Short-Term Memory.

    Directory of Open Access Journals (Sweden)

    Erik Karl Håkan Clemensson

    Full Text Available The BACHD rat is a recently developed transgenic animal model of Huntington disease, a progressive neurodegenerative disorder characterized by extensive loss of striatal neurons. Cognitive impairments are common among patients, and characterization of similar deficits in animal models of the disease is therefore of interest. The present study assessed the BACHD rats' performance in the delayed alternation and the delayed non-matching to position test, two Skinner box-based tests of short-term memory function. The transgenic rats showed impaired performance in both tests, indicating general problems with handling basic aspects of the tests, while short-term memory appeared to be intact. Similar phenotypes have been found in rats with fronto-striatal lesions, suggesting that Huntington disease-related neuropathology might be present in the BACHD rats. Further analyses indicated that the performance deficit in the delayed alternation test might be due to impaired inhibitory control, which has also been implicated in Huntington disease patients. The study ultimately suggests that the BACHD rats might suffer from neuropathology and cognitive impairments reminiscent of those of Huntington disease patients.

  2. Show them the money? The role of pay, managerial need support, and justice in a self-determination theory model of intrinsic work motivation.

    Science.gov (United States)

    Olafsen, Anja H; Halvari, Hallgeir; Forest, Jacques; Deci, Edward L

    2015-08-01

    The link between money and motivation has been a debated topic for decades, especially in work organizations. However, field studies investigating the amount of pay in relation to employee motivation is lacking and there have been calls for empirical studies addressing compensation systems and motivation in the work domain. The purpose of this study was to examine outcomes associated with the amount of pay, and perceived distributive and procedural justice regarding pay in relation to those for perceived managerial need support. Participants were 166 bank employees who also reported on their basic psychological need satisfaction and intrinsic work motivation. SEM-analyses tested a self-determination theory (SDT) model, with satisfaction of the competence and autonomy needs as an intervening variable. The primary findings were that amount of pay and employees' perceived distributive justice regarding their pay were unrelated to employees' need satisfaction and intrinsic work motivation, but procedural justice regarding pay did affect these variables. However, managerial need support was the most important factor for promoting need satisfaction and intrinsic work motivation both directly, indirectly, and as a moderator in the model. Hence, the results of the present organizational field study support earlier laboratory experiments within the SDT framework showing that monetary rewards did not enhance intrinsic motivation. This seems to have profound implications for organizations concerned about motivating their employees. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  3. Xyloketal-derived small molecules show protective effect by decreasing mutant Huntingtin protein aggregates in Caenorhabditis elegans model of Huntington's disease.

    Science.gov (United States)

    Zeng, Yixuan; Guo, Wenyuan; Xu, Guangqing; Wang, Qinmei; Feng, Luyang; Long, Simei; Liang, Fengyin; Huang, Yi; Lu, Xilin; Li, Shichang; Zhou, Jiebin; Burgunder, Jean-Marc; Pang, Jiyan; Pei, Zhong

    2016-01-01

    Huntington's disease is an autosomal-dominant neurodegenerative disorder, with chorea as the most prominent manifestation. The disease is caused by abnormal expansion of CAG codon repeats in the IT15 gene, which leads to the expression of a glutamine-rich protein named mutant Huntingtin (Htt). Because of its devastating disease burden and lack of valid treatment, development of more effective therapeutics for Huntington's disease is urgently required. Xyloketal B, a natural product from mangrove fungus, has shown protective effects against toxicity in other neurodegenerative disease models such as Parkinson's and Alzheimer's diseases. To identify potential neuroprotective molecules for Huntington's disease, six derivatives of xyloketal B were screened in a Caenorhabditis elegans Huntington's disease model; all six compounds showed a protective effect. Molecular docking studies indicated that compound 1 could bind to residues GLN369 and GLN393 of the mutant Htt protein, forming a stable trimeric complex that can prevent the formation of mutant Htt aggregates. Taken together, we conclude that xyloketal derivatives could be novel drug candidates for treating Huntington's disease. Molecular target analysis is a good method to simulate the interaction between proteins and drug compounds. Further, protective candidate drugs could be designed in future using the guidance of molecular docking results.

  4. Xyloketal-derived small molecules show protective effect by decreasing mutant Huntingtin protein aggregates in Caenorhabditis elegans model of Huntington’s disease

    Science.gov (United States)

    Zeng, Yixuan; Guo, Wenyuan; Xu, Guangqing; Wang, Qinmei; Feng, Luyang; Long, Simei; Liang, Fengyin; Huang, Yi; Lu, Xilin; Li, Shichang; Zhou, Jiebin; Burgunder, Jean-Marc; Pang, Jiyan; Pei, Zhong

    2016-01-01

    Huntington’s disease is an autosomal-dominant neurodegenerative disorder, with chorea as the most prominent manifestation. The disease is caused by abnormal expansion of CAG codon repeats in the IT15 gene, which leads to the expression of a glutamine-rich protein named mutant Huntingtin (Htt). Because of its devastating disease burden and lack of valid treatment, development of more effective therapeutics for Huntington’s disease is urgently required. Xyloketal B, a natural product from mangrove fungus, has shown protective effects against toxicity in other neurodegenerative disease models such as Parkinson’s and Alzheimer’s diseases. To identify potential neuroprotective molecules for Huntington’s disease, six derivatives of xyloketal B were screened in a Caenorhabditis elegans Huntington’s disease model; all six compounds showed a protective effect. Molecular docking studies indicated that compound 1 could bind to residues GLN369 and GLN393 of the mutant Htt protein, forming a stable trimeric complex that can prevent the formation of mutant Htt aggregates. Taken together, we conclude that xyloketal derivatives could be novel drug candidates for treating Huntington’s disease. Molecular target analysis is a good method to simulate the interaction between proteins and drug compounds. Further, protective candidate drugs could be designed in future using the guidance of molecular docking results. PMID:27110099

  5. Polysaccharides from the Medicinal Mushroom Cordyceps taii Show Antioxidant and Immunoenhancing Activities in a D-Galactose-Induced Aging Mouse Model

    Directory of Open Access Journals (Sweden)

    Jian-Hui Xiao

    2012-01-01

    Full Text Available Cordyceps taii, an edible medicinal mushroom native to south China, is recognized as an unparalleled resource of healthy foods and drug discovery. In the present study, the antioxidant pharmacological properties of C. taii were systematically investigated. In vitro assays revealed the scavenging activities of the aqueous extract and polysaccharides of C. taii against various free radicals, that is, 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical. The EC50 values for superoxide anion-free radical ranged from 2.04 mg/mL to 2.49 mg/mL, which was at least 2.6-fold stronger than that of antioxidant thiourea. The polysaccharides also significantly enhanced the antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase and markedly decreased the malondialdehyde production of lipid peroxidation in a D-galactose-induced aging mouse model. Interestingly, the immune function of the administration group was significantly boosted compared with the D-galactose-induced aging model group. Therefore, the C. taii polysaccharides possessed potent antioxidant activity closely associated with immune function enhancement and free radical scavenging. These findings suggest that the polysaccharides are a promising source of natural antioxidants and antiaging drugs. Consequently, a preliminary chemical investigation was performed using gas chromatography-mass spectroscopy and revealed that the polysaccharides studied were mainly composed of glucose, mannose, and galactose. Fourier-transform infrared spectra also showed characteristic polysaccharide absorption bands.

  6. Characterization of chronic constriction of the saphenous nerve, a model of neuropathic pain in mice showing rapid molecular and electrophysiological changes.

    Science.gov (United States)

    Walczak, Jean-Sébastien; Pichette, Vincent; Leblond, François; Desbiens, Karine; Beaulieu, Pierre

    2006-05-15

    Neuropathic pain is one of the most inextricable problems encountered in clinics, because few facts are known about its etiology. Nerve injury often leads to allodynia and hyperalgesia, which are symptoms of neuropathic pain. The aim of this study was to understand some molecular and electrophysiological mechanisms of neuropathic pain after chronic constriction of the saphenous nerve (CCS) in mice. After surgery, CCS mice displayed significant allodynia and hyperalgesia, which were sensitive to acute systemic injection of morphine (4 mg/kg), gabapentin (50 mg/kg), amitriptyline (10 mg/kg), and the cannabinoid agonist WIN 55,212-2 (5 mg/kg). These behavioral changes were accompanied after surgery by an increase of c-Fos expression and by an overexpression of mu-opioid and cannabinoid CB1 and CB2 receptors in the spinal cord and the dorsal hind paw skin. In combination with the skin-nerve preparation, this model showed a decrease in functional receptive fields downstream to the injury and the apparition of A-fiber ectopic discharges. In conclusion, CCS injury induced behavioral, molecular, and electrophysiological rearrangements that might help us in better understanding the peripheral mechanisms of neuropathic pain. This model takes advantage of the possible use in the future of genetically modified mice and of an exclusively sensory nerve for a comprehensive study of peripheral mechanisms of neuropathic pain. Copyright 2006 Wiley-Liss, Inc.

  7. A water-soluble extract from Cucurbita moschata shows anti-obesity effects by controlling lipid metabolism in a high fat diet-induced obesity mouse model.

    Science.gov (United States)

    Choi, Hyounjeong; Eo, Haekwan; Park, Kyoungcheol; Jin, Mirim; Park, Eun-Jin; Kim, Seon-Hee; Park, Jeong Euy; Kim, Sunyoung

    2007-08-03

    During the screening of a variety of plant sources for their anti-obesity activity, it was found that a water-soluble extract, named PG105, prepared from stem parts of Cucurbita moschata, contains potent anti-obesity activities in a high fat diet-induced obesity mouse model. In this animal model, increases in body weight and fat storage were suppressed by 8-week oral administration of PG105 at 500 mg/kg, while the overall amount of food intake was not affected. Furthermore, PG105 protected the development of fatty liver and increased the hepatic beta-oxidation activity. Results from blood analysis showed that the levels of triglyceride and cholesterol were significantly lowered by PG105 administration, and also that the level of leptin was reduced, while that of adiponectin was increased. To understand the underlying mechanism at the molecular level, the effects of PG105 were examined on the expression of the genes involved in lipid metabolism by Northern blot analysis. In the liver of PG105-treated mice, the mRNA level of lipogenic genes such as SREBP-1c and SCD-1 was decreased, while that of lipolytic genes such as PPARalpha, ACO-1, CPT-1, and UCP-2 was modestly increased. Our data suggest that PG105 may have great potential as a novel anti-obesity agent in that both inhibition of lipid synthesis and acceleration of fatty acid breakdown are induced by this reagent.

  8. Daily supplementation of D-ribose shows no therapeutic benefits in the MHC-I transgenic mouse model of inflammatory myositis.

    Directory of Open Access Journals (Sweden)

    William Coley

    Full Text Available BACKGROUND: Current treatments for idiopathic inflammatory myopathies (collectively called myositis focus on the suppression of an autoimmune inflammatory response within the skeletal muscle. However, it has been observed that there is a poor correlation between the successful suppression of muscle inflammation and an improvement in muscle function. Some evidence in the literature suggests that metabolic abnormalities in the skeletal muscle underlie the weakness that continues despite successful immunosuppression. We have previously shown that decreased expression of a purine nucleotide cycle enzyme, adenosine monophosphate deaminase (AMPD1, leads to muscle weakness in a mouse model of myositis and may provide a mechanistic basis for muscle weakness. One of the downstream metabolites of this pathway, D-ribose, has been reported to alleviate symptoms of myalgia in patients with a congenital loss of AMPD1. Therefore, we hypothesized that supplementing exogenous D-ribose would improve muscle function in the mouse model of myositis. We treated normal and myositis mice with daily doses of D-ribose (4 mg/kg over a 6-week time period and assessed its effects using a battery of behavioral, functional, histological and molecular measures. RESULTS: Treatment with D-ribose was found to have no statistically significant effects on body weight, grip strength, open field behavioral activity, maximal and specific forces of EDL, soleus muscles, or histological features. Histological and gene expression analysis indicated that muscle tissues remained inflamed despite treatment. Gene expression analysis also suggested that low levels of the ribokinase enzyme in the skeletal muscle might prevent skeletal muscle tissue from effectively utilizing D-ribose. CONCLUSIONS: Treatment with daily oral doses of D-ribose showed no significant effect on either disease progression or muscle function in the mouse model of myositis.

  9. Showing Value (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2009-06-01

    librarians on student achievement. Todd notes, “If we do not show value, we will not have a future. Evidence-based practice is not about the survival of school librarians, it’s about the survival of our students” (40. In this issue we feature school libraries and their connection to evidence based practice. Former Editor-in-Chief, Lindsay Glynn, began putting the wheels in motion for this feature almost a year ago. She invited Carol Gordon and Ross Todd to act as guest editors of the section, drawing upon their contacts and previous work in this field. The result is an issue with five feature articles exploring different aspects of the connection between school libraries and evidence based practice, from the theoretical to the practical. In addition, there is a thought-provoking Commentary by David Loertscher, asking whether we need the evolutionary model of evidence based practice, or something more revolutionary!In addition to the Feature section, we have a well-rounded issue with articles on the topics of library human resources, and the development of a scholars’ portal. As well, there are a record 10 evidence summaries and our educational EBL101 column. I hope there is something for everyone in this issue of EBLIP – enjoy, and see you soon in Stockholm!

  10. A Drosophila model of dominant inclusion body myopathy type 3 shows diminished myosin kinetics that reduce muscle power and yield myofibrillar defects.

    Science.gov (United States)

    Suggs, Jennifer A; Melkani, Girish C; Glasheen, Bernadette M; Detor