A Discrete Electromechanical Model for Human Cardiac Tissue: Effects of Stretch-Activated Currents and Stretch Conditions on Restitution Properties and Spiral Wave Dynamics

PubMed Central

Weise, Louis D.; Panfilov, Alexander V.

2013-01-01

We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006) and tension development (adjusted Niederer, Hunter, Smith, 2006 model) with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material). Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning. PMID:23527160

A discrete electromechanical model for human cardiac tissue: effects of stretch-activated currents and stretch conditions on restitution properties and spiral wave dynamics.

PubMed

Weise, Louis D; Panfilov, Alexander V

2013-01-01

We introduce an electromechanical model for human cardiac tissue which couples a biophysical model of cardiac excitation (Tusscher, Noble, Noble, Panfilov, 2006) and tension development (adjusted Niederer, Hunter, Smith, 2006 model) with a discrete elastic mass-lattice model. The equations for the excitation processes are solved with a finite difference approach, and the equations of the mass-lattice model are solved using Verlet integration. This allows the coupled problem to be solved with high numerical resolution. Passive mechanical properties of the mass-lattice model are described by a generalized Hooke's law for finite deformations (Seth material). Active mechanical contraction is initiated by changes of the intracellular calcium concentration, which is a variable of the electrical model. Mechanical deformation feeds back on the electrophysiology via stretch-activated ion channels whose conductivity is controlled by the local stretch of the medium. We apply the model to study how stretch-activated currents affect the action potential shape, restitution properties, and dynamics of spiral waves, under constant stretch, and dynamic stretch caused by active mechanical contraction. We find that stretch conditions substantially affect these properties via stretch-activated currents. In constantly stretched medium, we observe a substantial decrease in conduction velocity, and an increase of action potential duration; whereas, with dynamic stretch, action potential duration is increased only slightly, and the conduction velocity restitution curve becomes biphasic. Moreover, in constantly stretched medium, we find an increase of the core size and period of a spiral wave, but no change in rotation dynamics; in contrast, in the dynamically stretching medium, we observe spiral drift. Our results may be important to understand how altered stretch conditions affect the heart's functioning.

Noncommutative Jackiw-Pi model: One-loop renormalization

NASA Astrophysics Data System (ADS)

Bufalo, R.; Ghasemkhani, M.; Alipour, M.

2018-06-01

In this paper, we study the quantum behavior of the noncommutative Jackiw-Pi model. After establishing the Becchi-Rouet-Store-Tyutin (BRST) invariant action, the perturbative renormalizability is discussed, allowing us to introduce the renormalized mass and gauge coupling. We then proceed to compute the one-loop correction to the basic 1PI functions, necessary to determine the renormalized parameters (mass and charge), next we discuss the physical behavior of these parameters.

Hadron spectrum in quenched lattice QCD and distribution of zero modes

NASA Astrophysics Data System (ADS)

Iwasaki, Yoichi

1989-06-01

I report the results of the calculation of the hadron spectrum with the standard one-plaquette gauge action on a 16★★3★48 lattice at β=5.85 in the quenched lattice QCD. The result remarkably agrees with that of quark potential models for the case where the quark mass is equal to or is larger than the strange quark mass, even when one uses the standard one-plaquette gauge action. This is contrary to what is stated in the literature. We clarify the reason of the discrepancy, paying close attention to systematic errors in numerical calculations. Further, I show the distribution of zero modes of quark matrix, both in the cases of a RG improved gauge action and the standard action, and discuss the difference between the two cases.

Experimental evolution in silico: a custom-designed mathematical model for virulence evolution of Bacillus thuringiensis.

PubMed

Strauß, Jakob Friedrich; Crain, Philip; Schulenburg, Hinrich; Telschow, Arndt

2016-08-01

Most mathematical models on the evolution of virulence are based on epidemiological models that assume parasite transmission follows the mass action principle. In experimental evolution, however, mass action is often violated due to controlled infection protocols. This "theory-experiment mismatch" raises the question whether there is a need for new mathematical models to accommodate the particular characteristics of experimental evolution. Here, we explore the experimental evolution model system of Bacillus thuringiensis as a parasite and Caenorhabditis elegans as a host. Recent experimental studies with strict control of parasite transmission revealed that one-sided adaptation of B. thuringiensis with non-evolving hosts selects for intermediate or no virulence, sometimes coupled with parasite extinction. In contrast, host-parasite coevolution selects for high virulence and for hosts with strong resistance against B. thuringiensis. In order to explain the empirical results, we propose a new mathematical model that mimics the basic experimental set-up. The key assumptions are: (i) controlled parasite transmission (no mass action), (ii) discrete host generations, and (iii) context-dependent cost of toxin production. Our model analysis revealed the same basic trends as found in the experiments. Especially, we could show that resistant hosts select for highly virulent bacterial strains. Moreover, we found (i) that the evolved level of virulence is independent of the initial level of virulence, and (ii) that the average amount of bacteria ingested significantly affects the evolution of virulence with fewer bacteria ingested selecting for highly virulent strains. These predictions can be tested in future experiments. This study highlights the usefulness of custom-designed mathematical models in the analysis and interpretation of empirical results from experimental evolution. Copyright © 2016 The Authors. Published by Elsevier GmbH.. All rights reserved.

Phage-Bacterial Dynamics with Spatial Structure: Self Organization around Phage Sinks Can Promote Increased Cell Densities

PubMed Central

Bull, James J.; Christensen, Kelly A.; Scott, Carly; Crandall, Cameron J.; Krone, Stephen M.

2018-01-01

Bacteria growing on surfaces appear to be profoundly more resistant to control by lytic bacteriophages than do the same cells grown in liquid. Here, we use simulation models to investigate whether spatial structure per se can account for this increased cell density in the presence of phages. A measure is derived for comparing cell densities between growth in spatially structured environments versus well mixed environments (known as mass action). Maintenance of sensitive cells requires some form of phage death; we invoke death mechanisms that are spatially fixed, as if produced by cells. Spatially structured phage death provides cells with a means of protection that can boost cell densities an order of magnitude above that attained under mass action, although the effect is sometimes in the opposite direction. Phage and bacteria self organize into separate refuges, and spatial structure operates so that the phage progeny from a single burst do not have independent fates (as they do with mass action). Phage incur a high loss when invading protected areas that have high cell densities, resulting in greater protection for the cells. By the same metric, mass action dynamics either show no sustained bacterial elevation or oscillate between states of low and high cell densities and an elevated average. The elevated cell densities observed in models with spatial structure do not approach the empirically observed increased density of cells in structured environments with phages (which can be many orders of magnitude), so the empirical phenomenon likely requires additional mechanisms than those analyzed here. PMID:29382134

BF actions for the Husain-Kuchař model

NASA Astrophysics Data System (ADS)

Barbero G., J. Fernando; Villaseñor, Eduardo J.

2001-04-01

We show that the Husain-Kuchař model can be described in the framework of BF theories. This is a first step towards its quantization by standard perturbative quantum field theory techniques or the spin-foam formalism introduced in the space-time description of general relativity and other diff-invariant theories. The actions that we will consider are similar to the ones describing the BF-Yang-Mills model and some mass generating mechanisms for gauge fields. We will also discuss the role of diffeomorphisms in the new formulations that we propose.

Multistationarity in mass action networks with applications to ERK activation.

PubMed

Conradi, Carsten; Flockerzi, Dietrich

2012-07-01

Ordinary Differential Equations (ODEs) are an important tool in many areas of Quantitative Biology. For many ODE systems multistationarity (i.e. the existence of at least two positive steady states) is a desired feature. In general establishing multistationarity is a difficult task as realistic biological models are large in terms of states and (unknown) parameters and in most cases poorly parameterized (because of noisy measurement data of few components, a very small number of data points and only a limited number of repetitions). For mass action networks establishing multistationarity hence is equivalent to establishing the existence of at least two positive solutions of a large polynomial system with unknown coefficients. For mass action networks with certain structural properties, expressed in terms of the stoichiometric matrix and the reaction rate-exponent matrix, we present necessary and sufficient conditions for multistationarity that take the form of linear inequality systems. Solutions of these inequality systems define pairs of steady states and parameter values. We also present a sufficient condition to identify networks where the aforementioned conditions hold. To show the applicability of our results we analyse an ODE system that is defined by the mass action network describing the extracellular signal-regulated kinase (ERK) cascade (i.e. ERK-activation).

Short-Range Action, Focusing, and Saturation of Nuclear Forces in a Gravitational-Electrodynamic Model of GRT

NASA Astrophysics Data System (ADS)

Sukhanova, L. A.; Khlestkov, Yu. A.

2015-12-01

An equation for a massive vector field that explains the short-range action of nuclear forces has been obtained via a consistent solution of the Einstein-Maxwell-Lorentz equations in curved spacetime. The nucleus is identified with the throat, whose radius of curvature is adopted as the radius of the nucleus. In this gravitational model the experimentally observed proportionality of the radius of the nucleus to the cubic root of the mass number is obtained.

BSM Kaon Mixing at the Physical Point

NASA Astrophysics Data System (ADS)

Boyle, Peter; Garron, Nicolas; Kettle, Julia; Khamseh, Ava; Tsang, Justus Tobias

2018-03-01

We present a progress update on the RBC-UKQCD calculation of beyond the standard model (BSM) kaon mixing matrix elements at the physical point. Simulations are performed using 2+1 flavour domain wall lattice QCD with the Iwasaki gauge action at 3 lattice spacings and with pion masses ranging from 430 MeV to the physical pion mass.

Nonlocal gravity. Conceptual aspects and cosmological predictions

NASA Astrophysics Data System (ADS)

Belgacem, Enis; Dirian, Yves; Foffa, Stefano; Maggiore, Michele

2018-03-01

Even if the fundamental action of gravity is local, the corresponding quantum effective action, that includes the effect of quantum fluctuations, is a nonlocal object. These nonlocalities are well understood in the ultraviolet regime but much less in the infrared, where they could in principle give rise to important cosmological effects. Here we systematize and extend previous work of our group, in which it is assumed that a mass scale Λ is dynamically generated in the infrared, giving rise to nonlocal terms in the quantum effective action of gravity. We give a detailed discussion of conceptual aspects related to nonlocal gravity (including causality, degrees of freedom, ambiguities related to the boundary conditions of the nonlocal operator, scenarios for the emergence of a dynamical scale in the infrared) and of the cosmological consequences of these models. The requirement of providing a viable cosmological evolution severely restricts the form of the nonlocal terms, and selects a model (the so-called RR model) that corresponds to a dynamical mass generation for the conformal mode. For such a model: (1) there is a FRW background evolution, where the nonlocal term acts as an effective dark energy with a phantom equation of state, providing accelerated expansion without a cosmological constant. (2) Cosmological perturbations are well behaved. (3) Implementing the model in a Boltzmann code and comparing with observations we find that the RR model fits the CMB, BAO, SNe, structure formation data and local H0 measurements at a level statistically equivalent to ΛCDM. (4) Bayesian parameter estimation shows that the value of H0 obtained in the RR model is higher than in ΛCDM, reducing to 2.0σ the tension with the value from local measurements. (5) The RR model provides a prediction for the sum of neutrino masses that falls within the limits set by oscillation and terrestrial experiments (in contrast to ΛCDM, where letting the sum of neutrino masses vary as a free parameter within these limits, one hits the lower bound). (6) Gravitational waves propagate at the speed of light, complying with the limit from GW170817/GRB 170817A.

Predicting Physical Activity-Related Outcomes in Overweight and Obese Adults: A Health Action Process Approach.

PubMed

Hattar, Anne; Pal, Sebely; Hagger, Martin S

2016-03-01

We tested the adequacy of a model based on the Health Action Process Approach (HAPA) in predicting changes in psychological, body composition, and cardiovascular risk outcomes with respect to physical activity participation in overweight and obese adults. Measures of HAPA constructs (action and maintenance self-efficacy, outcome expectancies, action planning, risk perceptions, intentions, behaviour), psychological outcomes (quality of life, depression, anxiety, stress symptoms), body composition variables (body weight, body fat mass), cardiovascular risk measures (total cholesterol, low density lipoprotein), and self-reported physical activity behaviour were administered to participants (N = 74) at baseline, and 6 and 12 weeks later. Data were analysed using variance-based structural equation modelling with residualised change scores for HAPA variables. The model revealed effects of action self-efficacy and outcome expectancies on physical activity intentions, action self-efficacy on maintenance self-efficacy, and maintenance self-efficacy and intentions on action planning. Intention predicted psychological and body composition outcomes indirectly through physical activity behaviour. Action planning was a direct predictor of psychological, cardiovascular, and body composition outcomes. Data supported HAPA hypotheses in relation to intentions and behaviour, but not the role of action planning as a mediator of the intention-behaviour relationship. Action planning predicted outcomes independent of intentions and behaviour. © 2016 The International Association of Applied Psychology.

A conative educational model for an intervention program in obese youth.

PubMed

Vanhelst, Jérémy; Béghin, Laurent; Fardy, Paul Stephen; Bui-Xuan, Gilles; Mikulovic, Jacques

2012-06-07

Obesity in children has increased in recent years throughout the world and is associated with adverse health consequences. Early interventions, including appropriate pedagogy strategies, are important for a successful intervention program. The aim of this study was to assess changes in body mass index, the ability to perform sport activities, behavior in the classroom and academic performance following one year of a health-wellness intervention program in obese youth. The CEMHaVi program included 37 obese children (19 girls and 18 boys). Participants received an intervention program consisting of physical activity and health education. Assessment included body mass index, academic performance, classroom performance and ability to perform sport activities. Paired t tests were used to assess the effects of intervention, and chi square was used to assess inter-action between measures. Findings of the study suggest significant decrease in Z scores of Body Mass Index and an improvement of academic performance, classroom behavior and the ability to perform sport activities (p < 0.05). Chi square testing showed significant positive inter-actions between body mass index, classroom behavior and academic performance. Results following year one of CEMHaVi showed that a program of physical activity and health education had positive effects on obesity, behavior in the classroom and the ability to perform sport activities in obese adolescents. Significant inter-action in changes between variables was observed. Findings are important for designing intervention models to improve health in obese youth.

Testing the hierarchy of effects model: ParticipACTION's serial mass communication campaigns on physical activity in Canada.

PubMed

Craig, C L; Bauman, A; Reger-Nash, B

2010-03-01

The hierarchy of effects (HOE) model is often used in planning mass-reach communication campaigns to promote health, but has rarely been empirically tested. This paper examines Canada's 30 year ParticipACTION campaign to promote physical activity (PA). A cohort from the nationally representative 1981 Canada Fitness Survey was followed up in 1988 and 2002-2004. Modelling of these data tested whether the mechanisms of campaign effects followed the theoretical framework proposed in the HOE. Campaign awareness was measured in 1981. Outcome expectancy, attitudes, decision balance and future intention were asked in 1988. PA was assessed at all time points. Logistic regression was used to sequentially test mediating and moderating variables adjusting for age, sex and education. No selection bias was observed; however, relatively fewer respondents than non-respondents smoked or were underweight at baseline. Among those inactive at baseline, campaign awareness predicted outcome expectancy which in turn predicted positive attitude to PA. Positive attitudes predicted high decision balance, which predicted future intention. Future intention mediated the relationship between decision balance and sufficient activity. Among those sufficiently active at baseline, awareness was unrelated to outcome expectancy and inversely related to positive attitude. These results lend support to the HOE model, in that the effects of ParticipACTION's serial mass media campaigns were consistent with the sequential rollout of its messages, which in turn was associated with achieving an active lifestyle among those initially insufficiently active. This provides support to an often-used theoretical framework for designing health promotion media campaigns.

Quantifying fat, oil, and grease deposit formation kinetics.

PubMed

Iasmin, Mahbuba; Dean, Lisa O; Ducoste, Joel J

2016-01-01

Fat, oil, and grease (FOG) deposits formed in sanitary sewers are calcium-based saponified solids that are responsible for a significant number of nationwide sanitary sewer overflows (SSOs) across United States. In the current study, the kinetics of lab-based saponified solids were determined to understand the kinetics of FOG deposit formation in sewers for two types of fat (Canola and Beef Tallow) and two types of calcium sources (calcium chloride and calcium sulfate) under three pH (7 ± 0.5, 10 ± 0.5, and ≈14) and two temperature conditions (22 ± 0.5 and 45 ± 0.5 °C). The results of this study displayed quick reactions of a fraction of fats with calcium ions to form calcium based saponified solids. Results further showed that increased palmitic fatty acid content in source fats, the magnitude of the pH, and temperature significantly affect the FOG deposit formation and saponification rates. The experimental data of the kinetics were compared with two empirical models: a) Cotte saponification model and b) Foubert crystallization model and a mass-action based mechanistic model that included alkali driven hydrolysis of triglycerides. Results showed that the mass action based mechanistic model was able to predict changes in the rate of formation of saponified solids under the different experimental conditions compared to both empirical models. The mass-action based saponification model also revealed that the hydrolysis of Beef Tallow was slower compared to liquid Canola fat resulting in smaller quantities of saponified solids. This mechanistic saponification model, with its ability to track the saponified solids chemical precursors, may provide an initial framework to predict the spatial formation of FOG deposits in municipal sewers using system wide sewer collection modeling software. Copyright © 2015 Elsevier Ltd. All rights reserved.

Modeling metabolic networks in C. glutamicum: a comparison of rate laws in combination with various parameter optimization strategies

PubMed Central

Dräger, Andreas; Kronfeld, Marcel; Ziller, Michael J; Supper, Jochen; Planatscher, Hannes; Magnus, Jørgen B; Oldiges, Marco; Kohlbacher, Oliver; Zell, Andreas

2009-01-01

Background To understand the dynamic behavior of cellular systems, mathematical modeling is often necessary and comprises three steps: (1) experimental measurement of participating molecules, (2) assignment of rate laws to each reaction, and (3) parameter calibration with respect to the measurements. In each of these steps the modeler is confronted with a plethora of alternative approaches, e. g., the selection of approximative rate laws in step two as specific equations are often unknown, or the choice of an estimation procedure with its specific settings in step three. This overall process with its numerous choices and the mutual influence between them makes it hard to single out the best modeling approach for a given problem. Results We investigate the modeling process using multiple kinetic equations together with various parameter optimization methods for a well-characterized example network, the biosynthesis of valine and leucine in C. glutamicum. For this purpose, we derive seven dynamic models based on generalized mass action, Michaelis-Menten and convenience kinetics as well as the stochastic Langevin equation. In addition, we introduce two modeling approaches for feedback inhibition to the mass action kinetics. The parameters of each model are estimated using eight optimization strategies. To determine the most promising modeling approaches together with the best optimization algorithms, we carry out a two-step benchmark: (1) coarse-grained comparison of the algorithms on all models and (2) fine-grained tuning of the best optimization algorithms and models. To analyze the space of the best parameters found for each model, we apply clustering, variance, and correlation analysis. Conclusion A mixed model based on the convenience rate law and the Michaelis-Menten equation, in which all reactions are assumed to be reversible, is the most suitable deterministic modeling approach followed by a reversible generalized mass action kinetics model. A Langevin model is advisable to take stochastic effects into account. To estimate the model parameters, three algorithms are particularly useful: For first attempts the settings-free Tribes algorithm yields valuable results. Particle swarm optimization and differential evolution provide significantly better results with appropriate settings. PMID:19144170

Hybrid Markov-mass action law model for cell activation by rare binding events: Application to calcium induced vesicular release at neuronal synapses.

PubMed

Guerrier, Claire; Holcman, David

2016-10-18

Binding of molecules, ions or proteins to small target sites is a generic step of cell activation. This process relies on rare stochastic events where a particle located in a large bulk has to find small and often hidden targets. We present here a hybrid discrete-continuum model that takes into account a stochastic regime governed by rare events and a continuous regime in the bulk. The rare discrete binding events are modeled by a Markov chain for the encounter of small targets by few Brownian particles, for which the arrival time is Poissonian. The large ensemble of particles is described by mass action laws. We use this novel model to predict the time distribution of vesicular release at neuronal synapses. Vesicular release is triggered by the binding of few calcium ions that can originate either from the synaptic bulk or from the entry through calcium channels. We report here that the distribution of release time is bimodal although it is triggered by a single fast action potential. While the first peak follows a stimulation, the second corresponds to the random arrival over much longer time of ions located in the synaptic terminal to small binding vesicular targets. To conclude, the present multiscale stochastic modeling approach allows studying cellular events based on integrating discrete molecular events over several time scales.

A Semiclassical Derivation of the QCD Coupling

NASA Technical Reports Server (NTRS)

Batchelor, David

2009-01-01

The measured value of the QCD coupling alpha(sub s) at the energy M(sub Zo), the variation of alpha(sub s) as a function of energy in QCD, and classical relativistic dynamics are used to investigate virtual pairs of quarks and antiquarks in vacuum fluctuations. For virtual pairs of bottom quarks and antiquarks, the pair lifetime in the classical model agrees with the lifetime from quantum mechanics to good approximation, and the action integral in the classical model agrees as well with the action that follows from the Uncertainty Principle. This suggests that the particles might have small de Broglie wavelengths and behave with well-localized pointlike dynamics. It also permits alpha(sub s) at the mass energy twice the bottom quark mass to be expressed as a simple fraction: 3/16. This is accurate to approximately 10%. The model in this paper predicts the measured value of alpha(sub s)(M(sub Zo)) to be 0.121, which is in agreement with recent measurements within statistical uncertainties.

Microscopic models for uphill diffusion

NASA Astrophysics Data System (ADS)

Colangeli, Matteo; De Masi, Anna; Presutti, Errico

2017-10-01

We study a system of particles which jump on the sites of the interval [1, L] of { Z} . The density at the boundaries is kept fixed to simulate the action of mass reservoirs. The evolution depends on two parameters \

Baryon number, strangeness, and electric charge fluctuations in QCD at high temperature

NASA Astrophysics Data System (ADS)

Cheng, M.; Hegde, P.; Jung, C.; Karsch, F.; Kaczmarek, O.; Laermann, E.; Mawhinney, R. D.; Miao, C.; Petreczky, P.; Schmidt, C.; Soeldner, W.

2009-04-01

We analyze baryon number, strangeness, and electric charge fluctuations as well as their correlations in QCD at high temperature. We present results obtained from lattice calculations performed with an improved staggered fermion action (p4 action) at two values of the lattice cutoff with almost physical up and down quark masses and a physical value for the strange quark mass. We compare these results, with an ideal quark gas at high temperature and a hadron resonance gas model at low temperature. We find that fluctuations and correlations are well described by the former already for temperatures about 1.5 times the transition temperature. At low temperature qualitative features of the lattice results are quite well described by a hadron resonance gas model. Higher order cumulants, which become increasingly sensitive to the light pions, however, show deviations from a resonance gas in the vicinity of the transition temperature.

Cascading Air Power Effects Simulation (CAPES)

DTIC Science & Technology

2010-05-01

governments using autmated natural language processing techniques. New data on the attitudes of the masses and Arabic mass media were also collected using...environmental contexts. To meet this objective, new data was collected on the behavior of groups and governments using automated natural language processing...illustrate one fruitful avenue for future research. We show that we can model the first, second , and third order effects of US actions on group violence

New Physics Beyond the Standard Model

NASA Astrophysics Data System (ADS)

Cai, Haiying

In this thesis we discuss several extensons of the standard model, with an emphasis on the hierarchy problem. The hierachy problem related to the Higgs boson mass is a strong indication of new physics beyond the Standard Model. In the literature, several mechanisms, e.g. , supersymmetry (SUSY), the little Higgs and extra dimensions, are proposed to explain why the Higgs mass can be stabilized to the electroweak scale. In the Standard Model, the largest quadratically divergent contribution to the Higgs mass-squared comes from the top quark loop. We consider a few novel possibilities on how this contribution is cancelled. In the standard SUSY scenario, the quadratic divergence from the fermion loops is cancelled by the scalar superpartners and the SUSY breaking scale determines the masses of the scalars. We propose a new SUSY model, where the superpartner of the top quark is spin-1 rather than spin-0. In little Higgs theories, the Higgs field is realized as a psudo goldstone boson in a nonlinear sigma model. The smallness of its mass is protected by the global symmetry. As a variation, we put the little Higgs into an extra dimensional model where the quadratically divergent top loop contribution to the Higgs mass is cancelled by an uncolored heavy "top quirk" charged under a different SU(3) gauge group. Finally, we consider a supersymmetric warped extra dimensional model where the superpartners have continuum mass spectra. We use the holographic boundary action to study how a mass gap can arise to separate the zero modes from continuum modes. Such extensions of the Standard Model have novel signatures at the Large Hadron Collider.

User's instructions for the erythropoiesis regulatory model

NASA Technical Reports Server (NTRS)

1978-01-01

The purpose of the model provides a method to analyze some of the events that could account for the decrease in red cell mass observed in crewmen returning from space missions. The model is based on the premise that erythrocyte production is governed by the balance between oxygen supply and demand at a renal sensing site. Oxygen supply is taken to be a function of arterial oxygen tension, mean corpuscular hemoglobin concentration, oxy-hemoglobin carrying capacity, hematocrit, and blood flow. Erythrocyte destruction is based on the law of mass action. The instantaneous hematocrit value is derived by integrating changes in production and destruction rates and accounting for the degree of plasma dilution.

Two-flavor hybrid stars with the Dyson-Schwinger quark model

NASA Astrophysics Data System (ADS)

Wei, J. B.; Chen, H.; Schulze, H.-J.

2017-11-01

We study the properties of two-flavor quark matter in the Dyson-Schwinger model and investigate the possible consequences for hybrid neutron stars, with particular regard to the two-solar-mass limit. We find that with some extreme values of the model parameters, the mass fraction of two-flavor quark matter in heavy neutron stars can be as high as 30 percent and the possible energy release during the conversion from nucleonic neutron stars to hybrid stars can reach 1052 erg. Supported by NSFC (11305144, 11475149, 11303023), Central Universities (CUGL 140609) in China, “NewCompStar,” COST Action MP1304

Semi-classical Reissner-Nordstrom model for the structure of charged leptons

NASA Technical Reports Server (NTRS)

Rosen, G.

1980-01-01

The lepton self-mass problem is examined within the framework of the quantum theory of electromagnetism and gravity. Consideration is given to the Reissner-Nordstrom solution to the Einstein-Maxwell classical field equations for an electrically charged mass point, and the WKB theory for a semiclassical system with total energy zero is used to obtain an expression for the Einstein-Maxwell action factor. The condition obtained is found to account for the observed mass values of the three charged leptons, and to be in agreement with the correspondence principle.

Mathematical model of an indirect action fuel flow controller for aircraft jet engines

NASA Astrophysics Data System (ADS)

Tudosie, Alexandru-Nicolae

2017-06-01

The paper deals with a fuel mass flow rate controller with indirect action for aircraft jet engines. The author has identified fuel controller's main parts and its operation mode, then, based on these observations, one has determined motion equations of each main part, which have built system's non-linear mathematical model. In order to realize a better study this model was linearised (using the finite differences method) and then adimensionalized. Based on this new form of the mathematical model, after applying Laplace transformation, the embedded system (controller+engine) was described by the block diagram with transfer functions. Some Simulink-Matlab simulations were performed, concerning system's time behavior for step input, which lead to some useful conclusions and extension possibilities.

Dynamically avoiding fine-tuning the cosmological constant: the ``Relaxed Universe''

NASA Astrophysics Data System (ADS)

Bauer, Florian; Solà, Joan; Štefancić, Hrvoje

2010-12-01

We demonstrate that there exists a large class of Script F(R,Script G) action functionals of the scalar curvature and of the Gauß-Bonnet invariant which are able to relax dynamically a large cosmological constant (CC), whatever it be its starting value in the early universe. Hence, it is possible to understand, without fine-tuning, the very small current value Λ0 ~ H02 of the CC as compared to its theoretically expected large value in quantum field theory and string theory. In our framework, this relaxation appears as a pure gravitational effect, where no ad hoc scalar fields are needed. The action involves a positive power of a characteristic mass parameter, Script M, whose value can be, interestingly enough, of the order of a typical particle physics mass of the Standard Model of the strong and electroweak interactions or extensions thereof, including the neutrino mass. The model universe emerging from this scenario (the ``Relaxed Universe'') falls within the class of the so-called ΛXCDM models of the cosmic evolution. Therefore, there is a ``cosmon'' entity X (represented by an effective object, not a field), which in this case is generated by the effective functional Script F(R,Script G) and is responsible for the dynamical adjustment of the cosmological constant. This model universe successfully mimics the essential past epochs of the standard (or ``concordance'') cosmological model (ΛCDM). Furthermore, it provides interesting clues to the coincidence problem and it may even connect naturally with primordial inflation.

Casimir energies and special dimensions in a toy model for branes

NASA Astrophysics Data System (ADS)

Cohen, Isaac

1988-12-01

We consider a generalization to branes of the old action for the strings without reparamentrization invariance. These actions admit natural supplementary mass-shell conditions. By regularizing the Casimir energies we calculate the special dimensions at which these toy branes show vector massless states in its spectrum. They all turn out to be non-integers. On sabbatical leave from Departamento de Física, Facultad de Ciencias, Universidad Central de Venezuela, Apartado Postal 66961, Caracas 1061A, Venezuela.

Massive gravity in three dimensions.

PubMed

Bergshoeff, Eric A; Hohm, Olaf; Townsend, Paul K

2009-05-22

A particular higher-derivative extension of the Einstein-Hilbert action in three spacetime dimensions is shown to be equivalent at the linearized level to the (unitary) Pauli-Fierz action for a massive spin-2 field. A more general model, which also includes "topologically-massive" gravity as a special case, propagates the two spin-2 helicity states with different masses. We discuss the extension to massive N-extended supergravity, and we present a "cosmological" extension that admits an anti-de Sitter vacuum.

Three-dimensional stochastic model of actin–myosin binding in the sarcomere lattice

PubMed Central

Kayser-Herold, Oliver; Stojanovic, Boban; Nedic, Djordje; Irving, Thomas C.; Geeves, Michael A.

2016-01-01

The effect of molecule tethering in three-dimensional (3-D) space on bimolecular binding kinetics is rarely addressed and only occasionally incorporated into models of cell motility. The simplest system that can quantitatively determine this effect is the 3-D sarcomere lattice of the striated muscle, where tethered myosin in thick filaments can only bind to a relatively small number of available sites on the actin filament, positioned within a limited range of thermal movement of the myosin head. Here we implement spatially explicit actomyosin interactions into the multiscale Monte Carlo platform MUSICO, specifically defining how geometrical constraints on tethered myosins can modulate state transition rates in the actomyosin cycle. The simulations provide the distribution of myosin bound to sites on actin, ensure conservation of the number of interacting myosins and actin monomers, and most importantly, the departure in behavior of tethered myosin molecules from unconstrained myosin interactions with actin. In addition, MUSICO determines the number of cross-bridges in each actomyosin cycle state, the force and number of attached cross-bridges per myosin filament, the range of cross-bridge forces and accounts for energy consumption. At the macroscopic scale, MUSICO simulations show large differences in predicted force-velocity curves and in the response during early force recovery phase after a step change in length comparing to the two simplest mass action kinetic models. The origin of these differences is rooted in the different fluxes of myosin binding and corresponding instantaneous cross-bridge distributions and quantitatively reflects a major flaw of the mathematical description in all mass action kinetic models. Consequently, this new approach shows that accurate recapitulation of experimental data requires significantly different binding rates, number of actomyosin states, and cross-bridge elasticity than typically used in mass action kinetic models to correctly describe the biochemical reactions of tethered molecules and their interaction energetics. PMID:27864330

Three-dimensional stochastic model of actin–myosin binding in the sarcomere lattice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mijailovich, Srboljub M.; Kayser-Herold, Oliver; Stojanovic, Boban

2016-11-18

The effect of molecule tethering in three-dimensional (3-D) space on bimolecular binding kinetics is rarely addressed and only occasionally incorporated into models of cell motility. The simplest system that can quantitatively determine this effect is the 3-D sarcomere lattice of the striated muscle, where tethered myosin in thick filaments can only bind to a relatively small number of available sites on the actin filament, positioned within a limited range of thermal movement of the myosin head. Here we implement spatially explicit actomyosin interactions into the multiscale Monte Carlo platform MUSICO, specifically defining how geometrical constraints on tethered myosins can modulatemore » state transition rates in the actomyosin cycle. The simulations provide the distribution of myosin bound to sites on actin, ensure conservation of the number of interacting myosins and actin monomers, and most importantly, the departure in behavior of tethered myosin molecules from unconstrained myosin interactions with actin. In addition, MUSICO determines the number of cross-bridges in each actomyosin cycle state, the force and number of attached cross-bridges per myosin filament, the range of cross-bridge forces and accounts for energy consumption. At the macroscopic scale, MUSICO simulations show large differences in predicted force-velocity curves and in the response during early force recovery phase after a step change in length comparing to the two simplest mass action kinetic models. The origin of these differences is rooted in the different fluxes of myosin binding and corresponding instantaneous cross-bridge distributions and quantitatively reflects a major flaw of the mathematical description in all mass action kinetic models. Consequently, this new approach shows that accurate recapitulation of experimental data requires significantly different binding rates, number of actomyosin states, and cross-bridge elasticity than typically used in mass action kinetic models to correctly describe the biochemical reactions of tethered molecules and their interaction energetics.« less

Meson effective mass in the isospin medium in hard-wall AdS/QCD model

NASA Astrophysics Data System (ADS)

Mamedov, Shahin

2016-02-01

We study a mass splitting of the light vector, axial-vector, and pseudoscalar mesons in the isospin medium in the framework of the hard-wall model. We write an effective mass definition for the interacting gauge fields and scalar field introduced in gauge field theory in the bulk of AdS space-time. Relying on holographic duality we obtain a formula for the effective mass of a boundary meson in terms of derivative operator over the extra bulk coordinate. The effective mass found in this way coincides with the one obtained from finding of poles of the two-point correlation function. In order to avoid introducing distinguished infrared boundaries in the quantization formula for the different mesons from the same isotriplet we introduce extra action terms at this boundary, which reduces distinguished values of this boundary to the same value. Profile function solutions and effective mass expressions were found for the in-medium ρ , a_1, and π mesons.

Meson and baryon dispersion relations with Brillouin fermions

NASA Astrophysics Data System (ADS)

Dürr, Stephan; Koutsou, Giannis; Lippert, Thomas

2012-12-01

We study the dispersion relations of mesons and baryons built from Brillouin quarks on one Nf=2 gauge ensemble provided by QCDSF. For quark masses up to the physical strange quark mass, there is hardly any improvement over the Wilson discretization, if either action is link-smeared and tree-level clover improved. For quark masses in the range of the physical charm quark mass, the Brillouin action still shows a perfect relativistic behavior, while the Wilson action induces severe cutoff effects. As an application we determine the masses of the Ωc0, Ωcc+ and Ωccc++ baryons on that ensemble.

The effect of a prudent adaptive behaviour on disease transmission

NASA Astrophysics Data System (ADS)

Scarpino, Samuel V.; Allard, Antoine; Hébert-Dufresne, Laurent

2016-11-01

The spread of disease can be slowed by certain aspects of real-world social networks, such as clustering and community structure, and of human behaviour, including social distancing and increased hygiene, many of which have already been studied. Here, we consider a model in which individuals with essential societal roles--be they teachers, first responders or health-care workers--fall ill, and are replaced with healthy individuals. We refer to this process as relational exchange, and incorporate it into a dynamic network model to demonstrate that replacing individuals can accelerate disease transmission. We find that the effects of this process are trivial in the context of a standard mass-action model, but dramatic when considering network structure, featuring accelerating spread, discontinuous transitions and hysteresis loops. This result highlights the inability of mass-action models to account for many behavioural processes. Using empirical data, we find that this mechanism parsimoniously explains observed patterns across 17 influenza outbreaks in the USA at a national level, 25 years of influenza data at the state level, and 19 years of dengue virus data from Puerto Rico. We anticipate that our findings will advance the emerging field of disease forecasting and better inform public health decision making during outbreaks.

Origin of asteroids and the missing planet

NASA Technical Reports Server (NTRS)

Opik, E. J.

1977-01-01

Consideration is given to Ovenden's (1972) theory concerning the existence of a planet of 90 earth masses which existed from the beginning of the solar system and then disappeared 16 million years ago, leaving only asteroids. His model for secular perturbations is reviewed along with the principle of least interaction action (1972, 1973, 1975) on which the model is based. It is suggested that the structure of the asteroid belt and the origin of meteorites are associated with the vanished planet. A figure of 0.001 earth masses is proposed as a close estimate of the mass of the asteroidal belt. The hypothesis that the planet was removed through an explosion is discussed, noting the possible origin of asteroids in such a manner. Various effects of the explosion are postulated, including the direct impact of fragments on the earth, their impact on the sun and its decreased radiation, and the direct radiation of the explosion. A model for the disappearance of the planet by ejection in a gravitational encounter with a passing mass is also described.

Negative Coulomb damping, limit cycles, and self-oscillation of the vocal folds

NASA Astrophysics Data System (ADS)

Fulcher, Lewis P.; Scherer, Ronald C.; Melnykov, Artem; Gateva, Vesela; Limes, Mark E.

2006-05-01

An effective one-mass model of phonation is developed. It borrows the salient features of the classic two-mass model of human speech developed by Ishizaka, Matsudaira, and Flanagan. Their model is based on the idea that the oscillating vocal folds maintain their motion by deriving energy from the flow of air through the glottis. We argue that the essence of the action of the aerodynamic forces on the vocal folds is captured by negative Coulomb damping, which acts on the oscillator to energize it. A viscous force is added to include the effects of tissue damping. The solutions to this single oscillator model show that when it is excited by negative Coulomb damping, it will reach a limit cycle. Displacements, phase portraits, and energy histories are presented for two underdamped linear oscillators. A nonlinear force is added so that the variations of the fundamental frequency and the open quotient with lung pressure are comparable to the behavior of the two-mass model.

Blockspin renormalization-group study of color confinement due to violation of the non-Abelian Bianchi identity

NASA Astrophysics Data System (ADS)

Suzuki, Tsuneo

2018-02-01

Blockspin transformation of topological defects is applied to the violation of the non-Abelian Bianchi identity (VNABI) on lattice defined as Abelian monopoles. To get rid of lattice artifacts, we introduce (1) smooth gauge fixings such as the maximal center gauge (MCG), (2) blockspin transformations and (3) the tadpole-improved gauge action. The effective action can be determined by adopting the inverse Monte Carlo method. The coupling constants F (i ) of the effective action depend on the coupling of the lattice action β and the number of the blocking step n . But it is found that F (i ) satisfies a beautiful scaling; that is, they are a function of the product b =n a (β ) alone for lattice coupling constants 3.0 ≤β ≤3.9 and the steps of blocking 1 ≤n ≤12 . The effective action showing the scaling behavior can be regarded as an almost perfect action corresponding to the continuum limit, since a →0 as n →∞ for fixed b . The infrared effective monopole action keeps the global color invariance when smooth gauges such as MCG keeping the invariance are adopted. The almost perfect action showing the scaling is found to be independent of the smooth gauges adopted here as naturally expected from the gauge invariance of the continuum theory. Then we compare the results with those obtained by the analytic blocking method of topological defects from the continuum, assuming local two-point interactions are dominant as the infrared effective action. The action is formulated in the continuum limit while the couplings of these actions can be derived from simple observables calculated numerically on lattices with a finite lattice spacing. When use is made of Berezinskii-Kosterlitz-Thouless (BKT) transformation, the infrared monopole action can be transformed into that of the string model. Since large b =n a (β ) corresponds to the strong-coupling region in the string model, the physical string tension and the lowest glueball mass can be evaluated analytically with the use of the strong-coupling expansion of the string model. The almost perfect action gives us √{σ }≃1.3 √{σphys } for b ≥1.0 (σphys-1 /2) , whereas the scalar glueball mass is kept to be near M (0++)˜3.7 √{σphys } . In addition, using the effective action composed of 10 simple quadratic interactions alone, we can almost explain analytically the scaling function of the squared monopole density determined numerically for a large b region when b >1.2 (σphys-1 /2).

Equation of state and QCD transition at finite temperature

NASA Astrophysics Data System (ADS)

Bazavov, A.; Bhattacharya, T.; Cheng, M.; Christ, N. H.; Detar, C.; Ejiri, S.; Gottlieb, Steven; Gupta, R.; Heller, U. M.; Huebner, K.; Jung, C.; Karsch, F.; Laermann, E.; Levkova, L.; Miao, C.; Mawhinney, R. D.; Petreczky, P.; Schmidt, C.; Soltz, R. A.; Soeldner, W.; Sugar, R.; Toussaint, D.; Vranas, P.

2009-07-01

We calculate the equation of state in 2+1 flavor QCD at finite temperature with physical strange quark mass and almost physical light quark masses using lattices with temporal extent Nτ=8. Calculations have been performed with two different improved staggered fermion actions, the asqtad and p4 actions. Overall, we find good agreement between results obtained with these two O(a2) improved staggered fermion discretization schemes. A comparison with earlier calculations on coarser lattices is performed to quantify systematic errors in current studies of the equation of state. We also present results for observables that are sensitive to deconfining and chiral aspects of the QCD transition on Nτ=6 and 8 lattices. We find that deconfinement and chiral symmetry restoration happen in the same narrow temperature interval. In an appendix we present a simple parametrization of the equation of state that can easily be used in hydrodynamic model calculations. In this parametrization we include an estimate of current uncertainties in the lattice calculations which arise from cutoff and quark mass effects.

Final Rule for Control of Air Pollution From Motor Vehicles and New Motor Vehicle Engines; Increase of the Vehicle Mass for 3-Wheeled Motorcycles

EPA Pesticide Factsheets

This action changes the regulatory definition of a motorcycle to include 3-wheeled vehicles weighing up to 1749 pounds effective for 1998 and later model year motorcycles for which emission standards are in place.

A network dynamics approach to chemical reaction networks

NASA Astrophysics Data System (ADS)

van der Schaft, A. J.; Rao, S.; Jayawardhana, B.

2016-04-01

A treatment of a chemical reaction network theory is given from the perspective of nonlinear network dynamics, in particular of consensus dynamics. By starting from the complex-balanced assumption, the reaction dynamics governed by mass action kinetics can be rewritten into a form which allows for a very simple derivation of a number of key results in the chemical reaction network theory, and which directly relates to the thermodynamics and port-Hamiltonian formulation of the system. Central in this formulation is the definition of a balanced Laplacian matrix on the graph of chemical complexes together with a resulting fundamental inequality. This immediately leads to the characterisation of the set of equilibria and their stability. Furthermore, the assumption of complex balancedness is revisited from the point of view of Kirchhoff's matrix tree theorem. Both the form of the dynamics and the deduced behaviour are very similar to consensus dynamics, and provide additional perspectives to the latter. Finally, using the classical idea of extending the graph of chemical complexes by a 'zero' complex, a complete steady-state stability analysis of mass action kinetics reaction networks with constant inflows and mass action kinetics outflows is given, and a unified framework is provided for structure-preserving model reduction of this important class of open reaction networks.

The Endocrine Role of Estrogens on Human Male Skeleton

PubMed Central

Rochira, Vincenzo; Kara, Elda; Carani, Cesare

2015-01-01

Before the characterization of human and animal models of estrogen deficiency, estrogen action was confined in the context of the female bone. These interesting models uncovered a wide spectrum of unexpected estrogen actions on bone in males, allowing the formulation of an estrogen-centric theory useful to explain how sex steroids act on bone in men. Most of the principal physiological events that take place in the developing and mature male bone are now considered to be under the control of estrogen. Estrogen determines the acceleration of bone elongation at puberty, epiphyseal closure, harmonic skeletal proportions, the achievement of peak bone mass, and the maintenance of bone mass. Furthermore, it seems to crosstalk with androgen even in the determination of bone size, a more androgen-dependent phenomenon. At puberty, epiphyseal closure and growth arrest occur when a critical number of estrogens is reached. The same mechanism based on a critical threshold of serum estradiol seems to operate in men during adulthood for bone mass maintenance via the modulation of bone formation and resorption in men. This threshold should be better identified in-between the ranges of 15 and 25 pg/mL. Future basic and clinical research will optimize strategies for the management of bone diseases related to estrogen deficiency in men. PMID:25873947

Exploration of cellular reaction systems.

PubMed

Kirkilionis, Markus

2010-01-01

We discuss and review different ways to map cellular components and their temporal interaction with other such components to different non-spatially explicit mathematical models. The essential choices made in the literature are between discrete and continuous state spaces, between rule and event-based state updates and between deterministic and stochastic series of such updates. The temporal modelling of cellular regulatory networks (dynamic network theory) is compared with static network approaches in two first introductory sections on general network modelling. We concentrate next on deterministic rate-based dynamic regulatory networks and their derivation. In the derivation, we include methods from multiscale analysis and also look at structured large particles, here called macromolecular machines. It is clear that mass-action systems and their derivatives, i.e. networks based on enzyme kinetics, play the most dominant role in the literature. The tools to analyse cellular reaction networks are without doubt most complete for mass-action systems. We devote a long section at the end of the review to make a comprehensive review of related tools and mathematical methods. The emphasis is to show how cellular reaction networks can be analysed with the help of different associated graphs and the dissection into modules, i.e. sub-networks.

Vector mesons in the Nambu-Jona-Lasinio model

NASA Astrophysics Data System (ADS)

Schüren, C.; Döring, F.; Ruiz Arriola, E.; Goeke, K.

1993-12-01

We investigate solitonic solutions with baryon number equal to one of the semi-bosonized SU(2) Nambu-Jona-Lasinio model including σ -, π -, ρ -, A 1- and ω-mesons both on the chiral circle ( σ2r) + π2( r) = f2π) and beyond it ( σ2( r) + π2( r) ≠ f2π). The action is treated in the mesonic and baryonic sector in the leading order of the large- Nc expansion (one-quark-loop approximation). The UV-divergent real part of the effective action is rendered finite using different gauge-invariant regularization methods (Pauli-Villars and proper time). The parameters of the model are fixed in two different ways: either approximately by a heat kernel expansion of the effective action up to second order or by an exact calculation of the mesonic on-shell masses. This leaves the constituent quark mass as the only free parameter of the model. In the solitonic sector we pay special attention to the way the Wick rotation from euclidean space back to Minkowski space has to be performed. We get solitonic solutions from hedgehoglike field configurations on the chiral circle for a wide range of couplings. We also find that if the chiral-circle constraint is relaxed vector mesons provide stable solitonic solutions. Moreover, whether the baryon number is carried by the valence quarks or by the Dirac sea depends strongly on the particular values of the constituent quark mass. We also study the low-energy limit of the model and its connection to chiral perturbation theory. To this end a covariant-derivative expansion is performed in the presence of external fields. After integrating out the scalar, vector and axial degrees of freedom this leads to the corresponding low-energy parameters as e.g. pion radii and some threshold parameters for pion-pion scattering. Vector mesons provide a natural explanation for an axial coupling constant at the quark level gAQ lower than one. However, we find for the gAN of the nucleon noticeable deviations from the non-relativistic quark model prediction g AN = {5}/{3}g AQ. For the values of the parameters where solitons are found, pionic radii come out to be too small. Finally, the relation of the present model to other chiral soliton models as well as some effective lagrangians is displayed.

Accounting for Space—Quantification of Cell-To-Cell Transmission Kinetics Using Virus Dynamics Models.

PubMed

Kumberger, Peter; Durso-Cain, Karina; Uprichard, Susan L; Dahari, Harel; Graw, Frederik

2018-04-17

Mathematical models based on ordinary differential equations (ODE) that describe the population dynamics of viruses and infected cells have been an essential tool to characterize and quantify viral infection dynamics. Although an important aspect of viral infection is the dynamics of viral spread, which includes transmission by cell-free virions and direct cell-to-cell transmission, models used so far ignored cell-to-cell transmission completely, or accounted for this process by simple mass-action kinetics between infected and uninfected cells. In this study, we show that the simple mass-action approach falls short when describing viral spread in a spatially-defined environment. Using simulated data, we present a model extension that allows correct quantification of cell-to-cell transmission dynamics within a monolayer of cells. By considering the decreasing proportion of cells that can contribute to cell-to-cell spread with progressing infection, our extension accounts for the transmission dynamics on a single cell level while still remaining applicable to standard population-based experimental measurements. While the ability to infer the proportion of cells infected by either of the transmission modes depends on the viral diffusion rate, the improved estimates obtained using our novel approach emphasize the need to correctly account for spatial aspects when analyzing viral spread.

Non-perturbative quark mass renormalisation and running in N_{f}=3 QCD

NASA Astrophysics Data System (ADS)

Campos, I.; Fritzsch, P.; Pena, C.; Preti, D.; Ramos, A.; Vladikas, A.

2018-05-01

We determine from first principles the quark mass anomalous dimension in N_{f}=3 QCD between the electroweak and hadronic scales. This allows for a fully non-perturbative connection of the perturbative and non-perturbative regimes of the Standard Model in the hadronic sector. The computation is carried out to high accuracy, employing massless O (a)-improved Wilson quarks and finite-size scaling techniques. We also provide the matching factors required in the renormalisation of light quark masses from lattice computations with O (a)-improved Wilson fermions and a tree-level Symanzik improved gauge action. The total uncertainty due to renormalisation and running in the determination of light quark masses in the SM is thus reduced to about 1%.

Models for 60 double-lined binaries containing giants

NASA Astrophysics Data System (ADS)

Eggleton, Peter P.; Yakut, Kadri

2017-07-01

The observed masses, radii and temperatures of 60 medium- to long-period binaries, most of which contain a cool, evolved star and a hotter less evolved one, are compared with theoretical models which include (a) core convective overshooting, (b) mass-loss, possibly driven by dynamo action as in RS CVn binaries, and (c) tidal friction, including its effect on orbital period through magnetic braking. A reasonable fit is found in about 42 cases, but in 11 other cases the primaries appear to have lost either more mass or less mass than the models predict, and in 4 others the orbit is predicted to be either more or less circular than observed. Of the remaining three systems, two (γ Per and HR 8242) have a markedly 'overevolved' secondary, our explanation being that the primary component is the merged remnant of a former short-period sub-binary in a former triple system. The last system (V695 Cyg) defies any agreement at present. Mention is also made of three other systems (V643 Ori, OW Gem and V453 Cep), which are relevant to our discussion.

An investigation of the antidepressant action of xiaoyaosan in rats using ultra performance liquid chromatography-mass spectrometry combined with metabonomics.

PubMed

Gao, Xiao-Xia; Cui, Jie; Zheng, Xing-Yu; Li, Zhen-Yu; Choi, Young-Hae; Zhou, Yu-Zhi; Tian, Jun-Sheng; Xing, Jie; Tan, Xiao-Jie; Du, Guan-Hua; Qin, Xue-Mei

2013-07-01

A rapid, highly sensitive, and selective method was applied in a non-invasive way to investigate the antidepressant action of Xiaoyaosan (XYS) using ultra performance liquid chromatography-mass spectrometry (UPLC-MS) and chemometrics. Many significantly altered metabolites were used to explain the mechanism. Venlafaxine HCl and fluoxetine HCl were used as chemical positive control drugs with a relatively clear mechanism of action to evaluate the efficiency and to predict the mechanism of action of XYS. Urine obtained from rats subjected to chronic unpredictable mild stress (CUMS) was analyzed by UPLC-MS. Distinct changes in the pattern of metabolites in the rat urine after CUMS production and drug intervention were observed using partial least squares-discriminant analysis. The results of behavioral tests and multivariate analysis showed that CUMS was successfully reproduced, and a moderate-dose XYS produced significant therapeutic effects in the rodent model, equivalent to those of the positive control drugs, venlafaxine HCl and fluoxetine HCl. Metabolites with significant changes induced by CUMS were identified, and 17 biomarker candidates for stress and drug intervention were identified. The therapeutic effect of XYS on depression may involve regulation of the dysfunctions of energy metabolism, amino acid metabolism, and gut microflora changes. Metabonomic methods are valuable tools for measuring efficacy and mechanisms of action in the study of traditional Chinese medicines. Copyright © 2012 John Wiley & Sons, Ltd.

Action Dynamics of the Local Supercluster

NASA Astrophysics Data System (ADS)

Shaya, Edward J.; Tully, R. Brent; Hoffman, Yehuda; Pomarède, Daniel

2017-12-01

The fully nonlinear gravitationally induced trajectories of a nearly complete set of galaxies, groups, and clusters in the Local Supercluster are constructed in a numerical action method model constrained by data from the CosmicFlows survey and various distance indicators. We add the gravity field due to inhomogeneities external to the sample sphere by making use of larger-scale peculiar flow measurements. Assignments of total masses were made to find the best overall set of mutual attractions, as determined by a goodness criterion based on present-day radial velocities, individually for the Virgo Cluster, M31, and the Milky Way (MW), and via a mass-to-light ratio relationship for other masses. The low median chi-square found indicates that the model fits the present-day velocity flow well, but a slightly high mean chi-square may indicate that some masses underwent complex orbits. The best fit, when setting the value of H 0 to the CosmicFlows value of 75 km s‑1 Mpc‑1 and the WMAP value for Ω m = 0.244 consistent with that H 0, occurs with the following parameters: Ωorphan = 0.077 ± 0.016, M/{L}K=40+/- 2{L}100.15{M}ȯ /{L}ȯ (L 10 is the K-band luminosity in units of 1010 L ⊙), a Virgo mass of 6.3 ± 0.8 × 1014 M ⊙ (M/L K = 113 ± 15 M ⊙/L ⊙), and a mass for the MW plus M31 of 5.15 ± 0.35 × 1012 M ⊙. The best constant mass-to-light ratio is M/L K = 58 ± 3 M ⊙/L ⊙. The Virgocentric turnaround radius is 7.3 ± 0.3 Mpc. We explain several interesting trends in peculiar motions for various regions now that we can construct the 3D orbital histories.

Development and corroboration of a bioenergetics model for northern pikeminnow (Ptychocheilus oregonensis) feeding on juvenile salmonids in the Columbia River

USGS Publications Warehouse

Petersen, J.H.; Ward, D.L.

1999-01-01

A bioenergetics model was developed and corroborated for northern pikeminnow Ptychocheilus oregonensis, an important predator on juvenile salmonids in the Pacific Northwest. Predictions of modeled predation rate on salmonids were compared with field data from three areas of John Day Reservoir (Columbia River). To make bioenergetics model estimates of predation rate, three methods were used to approximate the change in mass of average predators during 30-d growth periods: observed change in mass between the first and the second month, predicted change in mass calculated with seasonal growth rates, and predicted change in mass based on an annual growth model. For all reservoir areas combined, bioenergetics model predictions of predation on salmon were 19% lower than field estimates based on observed masses, 45% lower than estimates based on seasonal growth rates, and 15% lower than estimates based on the annual growth model. For each growth approach, the largest differences in field-versus-model predation occurred at the midreservoir area (-84% to -67% difference). Model predictions of the rate of predation on salmonids were examined for sensitivity to parameter variation, swimming speed, sampling bias caused by gear selectivity, and asymmetric size distributions of predators. The specific daily growth rate of northern pikeminnow predicted by the model was highest in July and October and decreased during August. The bioenergetics model for northern pikeminnow performed well compared with models for other fish species that have been tested with field data. This model should be a useful tool for evaluating management actions such as predator removal, examining the influence of temperature on predation rates, and exploring interactions between predators in the Columbia River basin.

Combining Structural Probes in the Gas Phase - Ion Mobility- Resolved Action-FRET

NASA Astrophysics Data System (ADS)

Daly, Steven; MacAleese, Luke; Dugourd, Philippe; Chirot, Fabien

2018-01-01

In the context of native mass spectrometry, the development of gas-phase structural probes sensitive to the different levels of structuration of biomolecular assemblies is necessary to push forward conformational studies. In this paper, we provide the first example of the combination of ion mobility (IM) and Förster resonance energy transfer (FRET) measurements within the same experimental setup. The possibility to obtain mass- and mobility-resolved FRET measurements is demonstrated on a model peptide and applied to monitor the collision-induced unfolding of ubiquitin. [Figure not available: see fulltext.

Effects of mass media action on the Axelrod model with social influence

NASA Astrophysics Data System (ADS)

Rodríguez, Arezky H.; Moreno, Y.

2010-07-01

The use of dyadic interaction between agents, in combination with homophily (the principle that “likes attract”) in the Axelrod model for the study of cultural dissemination, has two important problems: the prediction of monoculture in large societies and an extremely narrow window of noise levels in which diversity with local convergence is obtained. Recently, the inclusion of social influence has proven to overcome them [A. Flache and M. W. Macy, e-print arXiv:0808.2710]. Here, we extend the Axelrod model with social influence interaction for the study of mass media effects through the inclusion of a superagent which acts over the whole system and has non-null overlap with each agent of the society. The dependence with different parameters as the initial social diversity, size effects, mass media strength, and noise is outlined. Our results might be relevant in several socioeconomic contexts and for the study of the emergence of collective behavior in complex social systems.

Effects of mass media action on the Axelrod model with social influence.

PubMed

Rodríguez, Arezky H; Moreno, Y

2010-07-01

The use of dyadic interaction between agents, in combination with homophily (the principle that "likes attract") in the Axelrod model for the study of cultural dissemination, has two important problems: the prediction of monoculture in large societies and an extremely narrow window of noise levels in which diversity with local convergence is obtained. Recently, the inclusion of social influence has proven to overcome them [A. Flache and M. W. Macy, e-print arXiv:0808.2710]. Here, we extend the Axelrod model with social influence interaction for the study of mass media effects through the inclusion of a superagent which acts over the whole system and has non-null overlap with each agent of the society. The dependence with different parameters as the initial social diversity, size effects, mass media strength, and noise is outlined. Our results might be relevant in several socioeconomic contexts and for the study of the emergence of collective behavior in complex social systems.

Understanding leptin-dependent regulation of skeletal homeostasis

PubMed Central

Motyl, Katherine J.; Rosen, Clifford J.

2012-01-01

Despite growing evidence for adipose tissue regulation of bone mass, the role of the adipokine leptin in bone remodeling remains controversial. The majority of in vitro studies suggest leptin enhances osteoblastic proliferation and differentiation while inhibiting adipogenic differentiation from marrow stromal cells. Alternatively, some evidence demonstrates either no effect or a pro-apoptotic action of leptin on stromal cells. Similarly, in vivo work has demonstrated both positive and negative effects of leptin on bone mass. Most of the literature supports the idea that leptin suppresses bone mass by acting in the brainstem to reduce serotonin-dependent sympathetic signaling from the ventromedial hypothalamus to bone. However, other studies have found partly or entirely contrasting actions of leptin. Recently one study found a significant effect of surgery alone with intracerebroventricular administration of leptin, a technique crucial for understanding centrally-mediated leptin regulation of bone. Thus, two mainstream hypotheses for the role of leptin on bone emerge: 1) direct regulation through increased osteoblast proliferation and differentiation and 2) indirect suppression of bone formation through a hypothalamic relay. At the present time, it remains unclear whether these effects are relevant in only extreme circumstances (i.e. models with complete deficiency) or play an important homeostatic role in the regulation of peak bone acquisition and skeletal remodeling. Ultimately, determining the actions of leptin on the skeleton will be critical for understanding how the obesity epidemic may be impacting the prevalence of osteoporosis. PMID:22534195

About Mass Transfer in Capillaries of Biological Systems under Influence of Vibrations

NASA Astrophysics Data System (ADS)

Prisniakov, K.

Vibrations accompany the flight of the manned spacecraft both at a stage of a orbital injection to an orbit, and during long flights (as noise), rendering undesirable physiological influence on crew, reducing serviceability and creating constant discomfort. The report represents attempt to predict a state of the cosmonaut in conditions of influence of vibrations for the period of start and stay in Space, being based on researches of mass transfer processes in capillary systems. For this purpose the original researches on heat and mass transfer processes with evaporation of liquids in capillary - porous structures in conditions of vibration actions and changes of a direction of action of gravitation are generalized. Report demonstrates the existence of modes at which increased or lowered mass transfer is achieved on border of separation "liquid - gas". The possible mechanism of influence of vibrations on evaporation of a liquid in capillaries is examined. The magnitudes of frequencies and amplitudes are submitted at which minimax characteristics are observed. The opportunity of application of the developed mathematical model of heat and mass transfer in capillary - porous structures to forecasting influence of vibrations for biological processes in capillaries of alive essences is analyzed. Such approach is justified on the mechanical nature of harmful influence of vibrations on an organism of the person. In addition the range of vibration frequencies which arise during space flights, corresponds to own resonant frequencies of a human body and his separate organs. Comparison of these resonant frequencies of a body of the person (5-80 Hertz) with vibration frequencies of optimum modes of heat and mass transfer in capillary - porous structures (20-40 Hertz) is shown their ranges of coverage. It gives the basis to assume existence of similar effects in capillaries of human body. It is supposed, that the difficulty of breath, change of a rhythm of breath, the subsequent weariness under vibration action are attributable to infringements of normal mass transfer between the inhaled air and blood. The opportunity of use of the received laws is discussed for assessment of influence of gravitational fields on intensity mass transfer in capillaries of biosystems also.

[The mass-spectrometry studies of the interaction of polyhexamethyleneguanidine with lipids].

PubMed

Lysytsia, A V; Rebriiev, A V

2014-01-01

In this work the integral components of the cytoplasmic membrane, lecithin and cholesterol were used for mass spectrometry analysis carried out on polyhexamethyleneguanidine (PHMG) mixtures with lipids. The study was performed by mass-spectrometry methods of the MALDI-TOF MS. Our results showed that despite the common use of PHGM polymer derivatives as disinfectants the persistent intermolecular complexes of PHMG oligomers with lipids were not formed. The binding of polycation PHMG with the membrane has been explained by the model proposed. According to this model PHGM can adhere to negatively charged plasma membrane of bacterial cell due to electrostatic interaction and the formation of loop-like structures. Similar stereochemistry mechanism makes the adsorption of the investigated polycation to membrane robust. The mechanism described together with additional destructive factors provides a reasonable explanation for the PHMG induced damage of bacterial cell plasma membrane and the biocide action of disinfectants prepared on the basis of the PHMG salts.

Functions of vasopressin and oxytocin in bone mass regulation

PubMed Central

Sun, Li; Tamma, Roberto; Yuen, Tony; Colaianni, Graziana; Ji, Yaoting; Cuscito, Concetta; Bailey, Jack; Dhawan, Samarth; Lu, Ping; Calvano, Cosima D.; Zhu, Ling-Ling; Zambonin, Carlo G.; Di Benedetto, Adriana; Stachnik, Agnes; Liu, Peng; Grano, Maria; Colucci, Silvia; Davies, Terry F.; New, Maria I.; Zallone, Alberta; Zaidi, Mone

2016-01-01

Prior studies show that oxytocin (Oxt) and vasopressin (Avp) have opposing actions on the skeleton exerted through high-affinity G protein-coupled receptors. We explored whether Avp and Oxtr can share their receptors in the regulation of bone formation by osteoblasts. We show that the Avp receptor 1α (Avpr1α) and the Oxt receptor (Oxtr) have opposing effects on bone mass: Oxtr−/− mice have osteopenia, and Avpr1α−/− mice display a high bone mass phenotype. More notably, this high bone mass phenotype is reversed by the deletion of Oxtr in Oxtr−/−:Avpr1α−/− double-mutant mice. However, although Oxtr is not indispensable for Avp action in inhibiting osteoblastogenesis and gene expression, Avp-stimulated gene expression is inhibited when the Oxtr is deleted in Avpr1α−/− cells. In contrast, Oxt does not interact with Avprs in vivo in a model of lactation-induced bone loss in which Oxt levels are high. Immunofluorescence microscopy of isolated nucleoplasts and Western blotting and MALDI-TOF of nuclear extracts show that Avp triggers Avpr1α localization to the nucleus. Finally, a specific Avpr2 inhibitor, tolvaptan, does not affect bone formation or bone mass, suggesting that Avpr2, which primarily functions in the kidney, does not have a significant role in bone remodeling. PMID:26699482

Prediction of enzyme classes from 3D structure: a general model and examples of experimental-theoretic scoring of peptide mass fingerprints of Leishmania proteins.

PubMed

Concu, Riccardo; Dea-Ayuela, Maria A; Perez-Montoto, Lazaro G; Bolas-Fernández, Francisco; Prado-Prado, Francisco J; Podda, Gianni; Uriarte, Eugenio; Ubeira, Florencio M; González-Díaz, Humberto

2009-09-01

The number of protein and peptide structures included in Protein Data Bank (PDB) and Gen Bank without functional annotation has increased. Consequently, there is a high demand for theoretical models to predict these functions. Here, we trained and validated, with an external set, a Markov Chain Model (MCM) that classifies proteins by their possible mechanism of action according to Enzyme Classification (EC) number. The methodology proposed is essentially new, and enables prediction of all EC classes with a single equation without the need for an equation for each class or nonlinear models with multiple outputs. In addition, the model may be used to predict whether one peptide presents a positive or negative contribution of the activity of the same EC class. The model predicts the first EC number for 106 out of 151 (70.2%) oxidoreductases, 178/178 (100%) transferases, 223/223 (100%) hydrolases, 64/85 (75.3%) lyases, 74/74 (100%) isomerases, and 100/100 (100%) ligases, as well as 745/811 (91.9%) nonenzymes. It is important to underline that this method may help us predict new enzyme proteins or select peptide candidates that improve enzyme activity, which may be of interest for the prediction of new drugs or drug targets. To illustrate the model's application, we report the 2D-Electrophoresis (2DE) isolation from Leishmania infantum as well as MADLI TOF Mass Spectra characterization and theoretical study of the Peptide Mass Fingerprints (PMFs) of a new protein sequence. The theoretical study focused on MASCOT, BLAST alignment, and alignment-free QSAR prediction of the contribution of 29 peptides found in the PMF of the new protein to specific enzyme action. This combined strategy may be used to identify and predict peptides of prokaryote and eukaryote parasites and their hosts as well as other superior organisms, which may be of interest in drug development or target identification.

An Exact Solvable Model of Rocket Dynamics in Atmosphere

ERIC Educational Resources Information Center

Rodrigues, H.; Pinho, M. O.; Portes, D., Jr.; Santiago, A.

2009-01-01

In basic physics courses at undergraduate level, the dynamics of self-propelled bodies is presented as an example of momentum conservation law applied to systems with time-varying mass. However, is often studied the simple situation of free motion or the motion under the action of a constant gravitational field. In this work, we investigate the…

Mass-Gathering Medical Care in Electronic Dance Music Festivals.

PubMed

FitzGibbon, Kathleen M; Nable, Jose V; Ayd, Benjamin; Lawner, Benjamin J; Comer, Angela C; Lichenstein, Richard; Levy, Matthew J; Seaman, Kevin G; Bussey, Ian

2017-10-01

Introduction Electronic dance music (EDM) festivals represent a unique subset of mass-gathering events with limited guidance through literature or legislation to guide mass-gathering medical care at these events. Hypothesis/Problem Electronic dance music festivals pose unique challenges with increased patient encounters and heightened patient acuity under-estimated by current validated casualty predication models. This was a retrospective review of three separate EDM festivals with analysis of patient encounters and patient transport rates. Data obtained were inserted into the predictive Arbon and Hartman models to determine estimated patient presentation rate and patient transport rates. The Arbon model under-predicted the number of patient encounters and the number of patient transports for all three festivals, while the Hartman model under-predicted the number of patient encounters at one festival and over-predicted the number of encounters at the other two festivals. The Hartman model over-predicted patient transport rates for two of the three festivals. Electronic dance music festivals often involve distinct challenges and current predictive models are inaccurate for planning these events. The formation of a cohesive incident action plan will assist in addressing these challenges and lead to the collection of more uniform data metrics. FitzGibbon KM , Nable JV , Ayd B , Lawner BJ , Comer AC , Lichenstein R , Levy MJ , Seaman KG , Bussey I . Mass-gathering medical care in electronic dance music festivals. Prehosp Disaster Med. 2017;32(5):563-567.

Preconceptions of Japanese Students Surveyed Using the Force and Motion Conceptual Evaluation

NASA Astrophysics Data System (ADS)

Ishimoto, Michi

2010-07-01

We assess the preconceptions of Japanese students about force and motion. The Force and Motion Conceptual Evaluation is a research-based, multiple-choice assessment of students' conceptual understanding of Newton's laws of motion and energy conservation. It is administered to determine the effectiveness of introductory mechanics curricula. In this study, the test was given to engineering students at the beginning of the first lecture of an introductory mechanics course for several years. Some students had minimal high school physics education, whereas the others had completed high school physics programs. To probe the students' preconceptions, we studied their test answers for each of the following categories: velocity, acceleration, Newton's first and second laws, Newton's third law, and energy conservation. We find that preconceptions, such as F ∝ mv, are prevalent among the students, regardless of their level of high school physics education. In the case of a collision between two objects, two preconceptions—a mass-dependent model and an action-dependent model—are prevalent. Typically, students combine the two models, with action dependency outweighing mass dependency. In the case of a sled sliding down a hill without friction at two heights and inclinations, a quarter of students used the height-dependent model to answer questions regarding speed and kinetic energy.

Physical interpretation of Jeans instability in quantum plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Akbari-Moghanjoughi, M.; International Centre for Advanced Studies in Physical Sciences and Institute for Theoretical Physics, Ruhr University Bochum, D-44780 Bochum

2014-08-15

In this paper, we use the quantum hydrodynamics and its hydrostatic limit to investigate the newly posed problem of Jeans instability in quantum plasmas from a different point of view in connection with the well-known Chandrasekhar mass-limit on highly collapsed degenerate stellar configurations. It is shown that the hydrodynamic stability of a spherically symmetric uniform quantum plasma with a given fixed mass is achieved by increase in its mass-density or decrease in the radius under the action of gravity. It is also remarked that for masses beyond the limiting Jeans-mass, the plasma becomes completely unstable and the gravitational collapse wouldmore » proceed forever. This limiting mass is found to depend strongly on the composition of the quantum plasma and the atomic-number of the constituent ions, where it is observed that heavier elements rather destabilize the quantum plasma hydrodynamically. It is also shown that the Chandrasekhar mass-limit for white dwarf stars can be directly obtained from the hydrostatic limit of our model.« less

Orexin Regulates Bone Remodeling via a Dominant Positive Central Action and a Subordinate Negative Peripheral Action

PubMed Central

Wei, Wei; Motoike, Toshiyuki; Krzeszinski, Jing Y.; Jin, Zixue; Xie, Xian-Jin; Dechow, Paul C.; Yanagisawa, Masashi; Wan, Yihong

2014-01-01

SUMMARY Orexin neuropeptides promote arousal, appetite, reward, and energy expenditure. However, whether orexin affects bone mass accrual is unknown. Here we show that orexin functions centrally through orexin receptor 2 (OX2R) in the brain to enhance bone formation. OX2R-null mice exhibit low-bone-mass owing to elevated circulating leptin; whereas central administration of an OX2R-selective agonist augments bone mass. Conversely, orexin also functions peripherally through orexin receptor 1 (OX1R) in the bone to suppress bone formation. OX1R-null mice exhibit high-bone-mass owing to a mesenchymal stem cell differentiation shift from adipocyte to osteoblast that results from higher osseous ghrelin expression. The central action is dominant over the peripheral action because bone mass is reduced in orexin-null and OX1R2R-double-null mice but enhanced in orexin over-expressing transgenic mice. These findings reveal orexin as a critical rheostat of skeletal homeostasis that exerts a yin-yang dual regulation, and highlight orexin as a therapeutic target for osteoporosis. PMID:24794976

Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

NASA Astrophysics Data System (ADS)

Ranković, Miloš Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

2016-02-01

We have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS2) and allows performing action spectroscopy. Electron impact MS2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1 s excitation. Both MS2 and single ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.

PURDU-WINCOF: A computer code for establishing the performance of a fan-compressor unit with water ingestion

NASA Technical Reports Server (NTRS)

Leonardo, M.; Tsuchiya, T.; Murthy, S. N. B.

1982-01-01

A model for predicting the performance of a multi-spool axial-flow compressor with a fan during operation with water ingestion was developed incorporating several two-phase fluid flow effects as follows: (1) ingestion of water, (2) droplet interaction with blades and resulting changes in blade characteristics, (3) redistribution of water and water vapor due to centrifugal action, (4) heat and mass transfer processes, and (5) droplet size adjustment due to mass transfer and mechanical stability considerations. A computer program, called the PURDU-WINCOF code, was generated based on the model utilizing a one-dimensional formulation. An illustrative case serves to show the manner in which the code can be utilized and the nature of the results obtained.

Conservation of ζ with radiative corrections from heavy field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanaka, Takahiro; Yukawa Institute for Theoretical Physics, Kyoto University,Kyoto, 606-8502; Urakawa, Yuko

2016-06-08

In this paper, we address a possible impact of radiative corrections from a heavy scalar field χ on the curvature perturbation ζ. Integrating out χ, we derive the effective action for ζ, which includes the loop corrections of the heavy field χ. When the mass of χ is much larger than the Hubble scale H, the loop corrections of χ only yield a local contribution to the effective action and hence the effective action simply gives an action for ζ in a single field model, where, as is widely known, ζ is conserved in time after the Hubble crossing time.more » Meanwhile, when the mass of χ is comparable to H, the loop corrections of χ can give a non-local contribution to the effective action. Because of the non-local contribution from χ, in general, ζ may not be conserved, even if the classical background trajectory is determined only by the evolution of the inflaton. In this paper, we derive the condition that ζ is conserved in time in the presence of the radiative corrections from χ. Namely, we show that when the dilatation invariance, which is a part of the diffeomorphism invariance, is preserved at the quantum level, the loop corrections of the massive field χ do not disturb the constant evolution of ζ at super Hubble scales. In this discussion, we show the Ward-Takahashi identity for the dilatation invariance, which yields a consistency relation for the correlation functions of the massive field χ.« less

Direct analysis by time-of-flight secondary ion mass spectrometry reveals action of bacterial laccase-mediator systems on both hardwood and softwood samples.

PubMed

Goacher, Robyn E; Braham, Erick J; Michienzi, Courtney L; Flick, Robert M; Yakunin, Alexander F; Master, Emma R

2017-12-29

The modification and degradation of lignin play a vital role in carbon cycling as well as production of biofuels and bioproducts. The possibility of using bacterial laccases for the oxidation of lignin offers a route to utilize existing industrial protein expression techniques. However, bacterial laccases are most frequently studied on small model compounds that do not capture the complexity of lignocellulosic materials. This work studied the action of laccases from Bacillus subtilis and Salmonella typhimurium (EC 1.10.3.2) on ground wood samples from yellow birch (Betula alleghaniensis) and red spruce (Picea rubens). The ability of bacterial laccases to modify wood can be facilitated by small molecule mediators. Herein, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), gallic acid and sinapic acid mediators were tested. Direct analysis of the wood samples was achieved by time-of-flight secondary ion mass spectrometry (ToF-SIMS), a surface sensitive mass spectrometry technique that has characteristic peaks for H, G and S lignin. The action of the bacterial laccases on both wood samples was demonstrated and revealed a strong mediator influence. The ABTS mediator led to delignification, evident in an overall increase of polysaccharide peaks in the residual solid, along with equal loss of G and S-lignin peaks. The gallic acid mediator demonstrated minimal laccase activity. Meanwhile, the sinapic acid mediator altered the S/G peak ratio consistent with mediator attaching to the wood solids. The current investigation demonstrates the action of bacterial laccase-mediator systems directly on woody materials, and the potential of using ToF-SIMS to uncover the fundamental and applied role of bacterial enzymes in lignocellulose conversion. © 2017 Scandinavian Plant Physiology Society.

Modelling the Dynamics of Bodies Self-Propelled by Exponential Mass Exhaustion

ERIC Educational Resources Information Center

Rodrigues, Hilario; Pinho, Marcos Oliveira; Portes, Dirceu, Jr.; Santiago, Arnaldo Jose

2008-01-01

We present a study of the ascending vertical motion of a self-propelled body under a uniform gravitational field suffering the action of two different types of air friction forces: linear on the velocity, which is valid for slowly moving bodies, and quadratic on the velocity. We study the special case where the thrust force is a decreasing…

Quantifying differences in the impact of variable chemistry on equilibrium uranium(VI) adsorption properties of aquifer sediments

USGS Publications Warehouse

Stoliker, Deborah L.; Kent, Douglas B.; Zachara, John M.

2011-01-01

Uranium adsorption-desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500-1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO22+ + 2CO32- = >SOUO2(CO3HCO3)2-, provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logKc) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logKc values. Using this approach, logKc values for seven sediment samples were not significantly different. However, a significant difference in adsorption properties between one sediment sample and the fines (Kc uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors.

Thermodynamic Analysis of Chemically Reacting Mixtures-Comparison of First and Second Order Models.

PubMed

Pekař, Miloslav

2018-01-01

Recently, a method based on non-equilibrium continuum thermodynamics which derives thermodynamically consistent reaction rate models together with thermodynamic constraints on their parameters was analyzed using a triangular reaction scheme. The scheme was kinetically of the first order. Here, the analysis is further developed for several first and second order schemes to gain a deeper insight into the thermodynamic consistency of rate equations and relationships between chemical thermodynamic and kinetics. It is shown that the thermodynamic constraints on the so-called proper rate coefficient are usually simple sign restrictions consistent with the supposed reaction directions. Constraints on the so-called coupling rate coefficients are more complex and weaker. This means more freedom in kinetic coupling between reaction steps in a scheme, i.e., in the kinetic effects of other reactions on the rate of some reaction in a reacting system. When compared with traditional mass-action rate equations, the method allows a reduction in the number of traditional rate constants to be evaluated from data, i.e., a reduction in the dimensionality of the parameter estimation problem. This is due to identifying relationships between mass-action rate constants (relationships which also include thermodynamic equilibrium constants) which have so far been unknown.

Some new results for the one-loop mass correction to the compactified λϕ4 theory

NASA Astrophysics Data System (ADS)

Fucci, Guglielmo; Kirsten, Klaus

2018-03-01

In this work, we consider the one-loop effective action of a self-interacting λϕ4 field propagating in a D dimensional Euclidean space endowed with d ≤ D compact dimensions. The main purpose of this paper is to compute the corrections to the mass of the field due to the presence of the compactified dimensions. Although the results of the one-loop correction to the mass of a λϕ4 field are very well known for compactified toroidal spaces, where the field obeys periodic boundary conditions, similar results do not appear to be readily available for cases in which the scalar field is subject to Dirichlet and Neumann boundary conditions. We apply the results of the one-loop mass correction to the study of the critical temperature in Ginzburg-Landau models.

Newborn screening for sickling and other haemoglobin disorders using tandem mass spectrometry: A pilot study of methodology in laboratories in England.

PubMed

Daniel, Yvonne A; Henthorn, Joan

2016-12-01

To determine (i) if electrospray mass spectrometry-mass spectrometry with the SpOtOn Diagnostics Ltd reagent kit for sickle cell screening could be integrated into the English newborn screening programme, under routine screening conditions, and provide mass spectrometry-mass spectrometry results which match existing methods, and (ii) if common action values could be set for all manufacturers in the study, for all assessed haemoglobins, to indicate which samples require further investigation. Anonymised residual blood spots were analysed using the SpOtOn reagent kit as per manufacturer's instructions, in parallel with existing techniques at four laboratories. Mass spectrometry-mass spectrometry instrumentation at Laboratories A and B was AB Sciex (Warrington, UK) AP4000, and at Laboratories C and D, Waters Micromass (Manchester, UK), Xevo TQMS and Premier, respectively. There were 23,898 results accepted from the four laboratories. Excellent specificity at 100% sensitivity was observed for haemoglobin S, haemoglobin C, haemoglobin E and haemoglobin O Arab . A common action value was not possible for Hb C, but action values were set by manufacturer. The two haemoglobin D Punjab cases at Laboratory D were not detected using the common action value. Conversely, false-positive results with haemoglobin D Punjab were a problem at the remaining three laboratories. This multicentre study demonstrates that it is possible to implement mass spectrometry-mass spectrometry into an established screening programme while maintaining consistency with existing methods for haemoglobinopathy screening. However, one of the instruments investigated cannot be recommended for use with this application. © The Author(s) 2016.

Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

DOE PAGES

Rankovic, Milos Lj.; Giuliani, Alexandre; Milosavljevic, Aleksandar R.

2016-02-11

In this study, we have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS 2) and allows performing action spectroscopy. Electron impact MS 2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1s excitation. Both MS 2 and singlemore » ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.« less

Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rankovic, Milos Lj.; Giuliani, Alexandre; Milosavljevic, Aleksandar R.

In this study, we have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS 2) and allows performing action spectroscopy. Electron impact MS 2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1s excitation. Both MS 2 and singlemore » ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.« less

Microscopic modeling of mass and charge distributions in the spontaneous fission of 240Pu

DOE PAGES

Sandhukhan, Jhilam; Nazarewicz, Witold; Schunck, Nicolas

2016-01-20

Here, we propose a methodology to calculate microscopically the mass and charge distributions of spontaneous fission yields. We combine the multidimensional minimization of collective action for fission with stochastic Langevin dynamics to track the relevant fission paths from the ground-state configuration up to scission. The nuclear potential energy and collective inertia governing the tunneling motion are obtained with nuclear density functional theory in the collective space of shape deformations and pairing. Moreover, we obtain a quantitative agreement with experimental data and find that both the charge and mass distributions in the spontaneous fission of 240Pu are sensitive both to themore » dissipation in collective motion and to adiabatic fission characteristics.« less

Complexity growth in minimal massive 3D gravity

NASA Astrophysics Data System (ADS)

Qaemmaqami, Mohammad M.

2018-01-01

We study the complexity growth by using "complexity =action " (CA) proposal in the minimal massive 3D gravity (MMG) model which is proposed for resolving the bulk-boundary clash problem of topologically massive gravity (TMG). We observe that the rate of the complexity growth for Banados-Teitelboim-Zanelli (BTZ) black hole saturates the proposed bound by physical mass of the BTZ black hole in the MMG model, when the angular momentum parameter and the inner horizon of black hole goes to zero.

23 CFR 810.208 - Action by the Federal Highway Administrator.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Action by the Federal Highway Administrator. 810.208 Section 810.208 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Making Highway Rights-of-Way Available for Mass...

23 CFR 810.208 - Action by the Federal Highway Administrator.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Action by the Federal Highway Administrator. 810.208 Section 810.208 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Making Highway Rights-of-Way Available for Mass...

23 CFR 810.208 - Action by the Federal Highway Administrator.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 23 Highways 1 2012-04-01 2012-04-01 false Action by the Federal Highway Administrator. 810.208 Section 810.208 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Making Highway Rights-of-Way Available for Mass...

Accelerating risk reduction in Kathmandu Valley, Nepal: Theory-based mass-media intervention proven to increase knowledge of, belief in, and intent to support earthquake-resistant construction.

NASA Astrophysics Data System (ADS)

Sanquini, A.; Thapaliya, S. M.; Wood, M. M.; Hilley, G. E.

2015-12-01

Motivating people in rapidly urbanizing areas to take protective actions against natural disasters faces the challenge that these people often do not know what actions to take, do not believe that such actions are effective, and/or believe that the disaster will not happen to them within their lifetimes. Thus, finding demonstrated ways of motivating people to take protective action likely constitutes a grand challenge for natural disaster risk reduction and resiliency, because it may be one of the largest, lowest-cost sources of potential risk reduction in these situations. We developed a theory-based documentary film (hereafter, intervention) targeted at motivating retrofits of local school buildings, and tested its effectiveness in Kathmandu, Nepal, using a matched-pair clustered randomized controlled trial. The intervention features Nepalese who have strengthened their school buildings as role models to others at schools still in need of seismic work. It was tested at 16 Kathmandu Valley schools from November 2014 through March 2015. Schools were matched into 8 pairs, then randomly assigned to see either the intervention film or an attention placebo control film on an unrelated topic. Testing was completed just five weeks before the M 7.8 Gorkha earthquake struck central Nepal. When compared to the control schools, the schools whose community members saw the retrofit intervention film increased their knowledge of specific actions to take in support of earthquake-resistant construction, belief in the feasibility of making buildings earthquake-resistant, willingness to support seismic strengthening of the local school building, and likelihood to recommend to others that they build earthquake-resistant homes, which have all been shown to be precursors to taking self-protective action. This suggests that employing a mass-media intervention featuring community members who have already taken the desired action increases factors that may accelerate adoption of risk reduction actions by others who are similar to them.

Foot speed, foot-strike and footwear: linking gait mechanics and running ground reaction forces.

PubMed

Clark, Kenneth P; Ryan, Laurence J; Weyand, Peter G

2014-06-15

Running performance, energy requirements and musculoskeletal stresses are directly related to the action-reaction forces between the limb and the ground. For human runners, the force-time patterns from individual footfalls can vary considerably across speed, foot-strike and footwear conditions. Here, we used four human footfalls with distinctly different vertical force-time waveform patterns to evaluate whether a basic mechanical model might explain all of them. Our model partitions the body's total mass (1.0 Mb) into two invariant mass fractions (lower limb=0.08, remaining body mass=0.92) and allows the instantaneous collisional velocities of the former to vary. The best fits achieved (R(2) range=0.95-0.98, mean=0.97 ± 0.01) indicate that the model is capable of accounting for nearly all of the variability observed in the four waveform types tested: barefoot jog, rear-foot strike run, fore-foot strike run and fore-foot strike sprint. We conclude that different running ground reaction force-time patterns may have the same mechanical basis. © 2014. Published by The Company of Biologists Ltd.

Modeling and Control of a Fixed Wing Tilt-Rotor Tri-Copter

NASA Astrophysics Data System (ADS)

Summers, Alexander

The following thesis considers modeling and control of a fixed wing tilt-rotor tri-copter. An emphasis of the conceptual design is made toward payload transport. Aerodynamic panel code and CAD design provide the base aerodynamic, geometric, mass, and inertia properties. A set of non-linear dynamics are created considering gravity, aerodynamics in vertical takeoff and landing (VTOL) and forward flight, and propulsion applied to a three degree of freedom system. A transition strategy, that removes trajectory planning by means of scheduled inputs, is theorized. Three discrete controllers, utilizing separate control techniques, are applied to ensure stability in the aerodynamic regions of VTOL, transition, and forward flight. The controller techniques include linear quadratic regulation, full state integral action, gain scheduling, and proportional integral derivative (PID) flight control. Simulation of the model control system for flight from forward to backward transition is completed with mass and center of gravity variation.

Monte Carlo simulation of the transmission of measles: Beyond the mass action principle

NASA Astrophysics Data System (ADS)

Zekri, Nouredine; Clerc, Jean Pierre

2002-04-01

We present a Monte Carlo simulation of the transmission of measles within a population sample during its growing and equilibrium states by introducing two different vaccination schedules of one and two doses. We study the effects of the contact rate per unit time ξ as well as the initial conditions on the persistence of the disease. We found a weak effect of the initial conditions while the disease persists when ξ lies in the range 1/L-10/L (L being the latent period). Further comparison with existing data, prediction of future epidemics and other estimations of the vaccination efficiency are provided. Finally, we compare our approach to the models using the mass action principle in the first and another epidemic region and found the incidence independent of the number of susceptibles after the epidemic peak while it strongly fluctuates in its growing region. This method can be easily applied to other human, animal, and plant diseases and includes more complicated parameters.

A proposal of a renormalizable Nambu-Jona-Lasinio model

NASA Astrophysics Data System (ADS)

Cabo Montes de Oca, Alejandro

2018-03-01

A local and gauge invariant gauge field model including Nambu-Jona-Lasinio (NJL) and QCD Lagrangian terms in its action is introduced. Surprisingly, it becomes power counting renormalizable. This occurs thanks to the presence of action terms which modify the quark propagators, to become more decreasing that the Dirac one at large momenta in a Lee-Wick form, implying power counting renormalizability. The appearance of finite quark masses already in the tree approximation in the scheme is determined by the fact that the new action terms explicitly break chiral invariance. In this starting work we present the renormalized Feynman diagram expansion of the model and derive the formula for the degree of divergence of the diagrams. An explanation for the usual exclusion of the added Lagrangian terms is presented. In addition, the primitíve divergent graphs are identified. We start their evaluation by calculating the simpler contribution to the gluon polarization operator. The divergent and finite parts both result transverse as required by gauge invariance. The full evaluation of the various primitive divergences, which are required for completely defining the counterterm Feynman expansion will be considered in coming works, for further allowing to discuss the flavour symmetry breaking and unitarity.

Mechanistic kinetic modeling generates system-independent P-glycoprotein mediated transport elementary rate constants for inhibition and, in combination with 3D SIM microscopy, elucidates the importance of microvilli morphology on P-glycoprotein mediated efflux activity.

PubMed

Ellens, Harma; Meng, Zhou; Le Marchand, Sylvain J; Bentz, Joe

2018-06-01

In vitro transporter kinetics are typically analyzed by steady-state Michaelis-Menten approximations. However, no clear evidence exists that these approximations, applied to multiple transporters in biological membranes, yield system-independent mechanistic parameters needed for reliable in vivo hypothesis generation and testing. Areas covered: The classical mass action model has been developed for P-glycoprotein (P-gp) mediated transport across confluent polarized cell monolayers. Numerical integration of the mass action equations for transport using a stable global optimization program yields fitted elementary rate constants that are system-independent. The efflux active P-gp was defined by the rate at which P-gp delivers drugs to the apical chamber, since as much as 90% of drugs effluxed by P-gp partition back into nearby microvilli prior to reaching the apical chamber. The efflux active P-gp concentration was 10-fold smaller than the total expressed P-gp for Caco-2 cells, due to their microvilli membrane morphology. The mechanistic insights from this analysis are readily extrapolated to P-gp mediated transport in vivo. Expert opinion: In vitro system-independent elementary rate constants for transporters are essential for the generation and validation of robust mechanistic PBPK models. Our modeling approach and programs have broad application potential. They can be used for any drug transporter with minor adaptations.

The Relationship Between School Holidays and Transmission of Influenza in England and Wales

PubMed Central

Jackson, Charlotte; Vynnycky, Emilia; Mangtani, Punam

2016-01-01

Abstract School closure is often considered as an influenza control measure, but its effects on transmission are poorly understood. We used 2 approaches to estimate how school holidays affect the contact parameter (the per capita rate of contact sufficient for infection transmission) for influenza using primary care data from England and Wales (1967–2000). Firstly, we fitted an age-structured susceptible-infectious-recovered model to each year's data to estimate the proportional change in the contact parameter during school holidays as compared with termtime. Secondly, we calculated the percentage difference in the contact parameter between holidays and termtime from weekly values of the contact parameter, estimated directly from simple mass-action models. Estimates were combined using random-effects meta-analysis, where appropriate. From fitting to the data, the difference in the contact parameter among children aged 5–14 years during holidays as compared with termtime ranged from a 36% reduction to a 17% increase; estimates were too heterogeneous for meta-analysis. Based on the simple mass-action model, the contact parameter was 17% (95% confidence interval: 10, 25) lower during holidays than during termtime. Results were robust to the assumed proportions of infections that were reported and individuals who were susceptible when the influenza season started. We conclude that school closure may reduce transmission during influenza outbreaks. PMID:27744384

Model-based active control of a continuous structure subjected to moving loads

NASA Astrophysics Data System (ADS)

Stancioiu, D.; Ouyang, H.

2016-09-01

Modelling of a structure is an important preliminary step of structural control. The main objectives of the modelling, which are almost always antagonistic are accuracy and simplicity of the model. The first part of this study focuses on the experimental and theoretical modelling of a structure subjected to the action of one or two decelerating moving carriages modelled as masses. The aim of this part is to obtain a simple but accurate model which will include not only the structure-moving load interaction but also the actuators dynamics. A small scale rig is designed to represent a four-span continuous metallic bridge structure with miniature guiding rails. A series of tests are run subjecting the structure to the action of one or two minicarriages with different loads that were launched along the structure at different initial speeds. The second part is dedicated to model based control design where a feedback controller is designed and tested against the validated model. The study shows that a positive position feedback is able to improve system dynamics but also shows some of the limitations of state- space methods for this type of system.

Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

NASA Astrophysics Data System (ADS)

Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

2016-06-01

A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/ z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV.

Aspects of Particle Physics Beyond the Standard Model

NASA Astrophysics Data System (ADS)

Lu, Xiaochuan

This dissertation describes a few aspects of particles beyond the Standard Model, with a focus on the remaining questions after the discovery of a Standard Model-like Higgs boson. In specific, three topics are discussed in sequence: neutrino mass and baryon asymmetry, naturalness problem of Higgs mass, and placing constraints on theoretical models from precision measurements. First, the consequence of the neutrino mass anarchy on cosmology is studied. Attentions are paid in particular to the total mass of neutrinos and baryon asymmetry through leptogenesis. With the assumption of independence among mass matrix entries in addition to the basis independence, Gaussian measure is the only choice. On top of Gaussian measure, a simple approximate U(1) flavor symmetry makes leptogenesis highly successful. Correlations between the baryon asymmetry and the light-neutrino quantities are investigated. Also discussed are possible implications of recently suggested large total mass of neutrinos by the SDSS/BOSS data. Second, the Higgs mass implies fine-tuning for minimal theories of weak-scale supersymmetry (SUSY). Non-decoupling effects can boost the Higgs mass when new states interact with the Higgs, but new sources of SUSY breaking that accompany such extensions threaten naturalness. I will show that two singlets with a Dirac mass can increase the Higgs mass while maintaining naturalness in the presence of large SUSY breaking in the singlet sector. The modified Higgs phenomenology of this scenario, termed "Dirac NMSSM", is also studied. Finally, the sensitivities of future precision measurements in probing physics beyond the Standard Model are studied. A practical three-step procedure is presented for using the Standard Model effective field theory (SM EFT) to connect ultraviolet (UV) models of new physics with weak scale precision observables. With this procedure, one can interpret precision measurements as constraints on the UV model concerned. A detailed explanation is given for calculating the effective action up to one-loop order in a manifestly gauge covariant fashion. This covariant derivative expansion method dramatically simplifies the process of matching a UV model with the SM EFT, and also makes available a universal formalism that is easy to use for a variety of UV models. A few general aspects of RG running effects and choosing operator bases are discussed. Mapping results are provided between the bosonic sector of the SM EFT and a complete set of precision electroweak and Higgs observables to which present and near future experiments are sensitive. Many results and tools which should prove useful to those wishing to use the SM EFT are detailed in several appendices.

Physical limitations in sensors for a drag-free deep space probe

NASA Technical Reports Server (NTRS)

Juillerat, R.

1971-01-01

The inner perturbing forces acting on sensors were analyzed, taking into account the technological limitations imposed on the proof mass position pickup and proof mass acquisition system. The resulting perturbing accelerations are evaluated as a function of the drag-free sensor parameters. Perturbations included gravitational attraction, electrical action, magnetic action, pressure effects, radiation effects, and action of the position pickup. These data can be used to study the laws of guidance, providing an optimization of the space probe as a whole.

Constraints on planet X/Nemesis from Solar System's inner dynamics

NASA Astrophysics Data System (ADS)

Iorio, L.

2009-11-01

We use the corrections to the standard Newtonian/Einsteinian perihelion precessions of the inner planets of the Solar system, recently estimated by E.V. Pitjeva by fitting a huge planetary data set with the dynamical models of the EPM ephemerides, to put constraints on the position of a putative, yet undiscovered large body X of mass MX, not modelled in the EPM software. The direct action of X on the inner planets can be approximated by a elastic Hooke-type radial acceleration plus a term of comparable magnitude having a fixed direction in space pointing towards X. The perihelion precessions induced by them can be analytically worked out only for some particular positions of X in the sky; in general, numerical calculations are used. We show that the indirect effects of X on the inner planets through its action on the outer ones can be neglected, given the present-day level of accuracy in knowing . As a result, we find that Mars yields the tightest constraints, with the tidal parameter . To constrain rX we consider the case of a rock-ice planet with the mass of Mars and the Earth, a giant planet with the mass of Jupiter, a brown dwarf with MX = 80mJupiter, a red dwarf with M = 0.5Msolar and a Sun-mass body. For each of them we plot rminX as a function of the heliocentric latitude β and longitude λ. We also determine the forbidden spatial region for X by plotting its boundary surface in the three-dimensional space; it shows significant departures from spherical symmetry. A Mars-sized body can be found at not less than 70-85 au: such bounds are 147-175 au, 1006-1200 au, 4334-5170 au, 8113-9524 au and 10222-12000 au for a body with a mass equal to that of the Earth, Jupiter, a brown dwarf, red dwarf and the Sun, respectively.

Effects of crowders on the equilibrium and kinetic properties of protein aggregation

NASA Astrophysics Data System (ADS)

Bridstrup, John; Yuan, Jian-Min

2016-08-01

The equilibrium and kinetic properties of protein aggregation systems in the presence of crowders are investigated using simple, illuminating models based on mass-action laws. Our model yields analytic results for equilibrium properties of protein aggregates, which fit experimental data of actin and ApoC-II with crowders reasonably well. When the effects of crowders on rate constants are considered, our kinetic model is in good agreement with experimental results for actin with dextran as the crowder. Furthermore, the model shows that as crowder volume fraction increases, the length distribution of fibrils becomes narrower and shifts to shorter values due to volume exclusion.

Quantitative evaluation of intensive remedial action using long-term monitoring and tracer data at a DNAPL contaminated site, Wonju, Korea

NASA Astrophysics Data System (ADS)

Lee, S. S.; Kim, H. J.; Kim, M. O.; Lee, K.; Lee, K. K.

2016-12-01

A study finding evidence of remediation represented on monitoring data before and after in site intensive remedial action was performed with various quantitative evaluation methods such as mass discharge analysis, tracer data, statistical trend analysis, and analytical solutions at DNAPL contaminated site, Wonju, Korea. Remediation technologies such as soil vapor extraction, soil flushing, biostimulation, and pump-and-treat have been applied to eliminate the contaminant sources of trichloroethylene (TCE) and to prevent the migration of TCE plume from remediation target zones. Prior to the remediation action, the concentration and mass discharges of TCE at all transects were affected by seasonal recharge variation and residual DNAPLs sources. After the remediation, the effect of remediation took place clearly at the main source zone and industrial complex. By tracing a time-series of plume evolution, a greater variation in the TCE concentrations was detected at the plumes near the source zones compared to the relatively stable plumes in the downstream. The removal amount of the residual source mass during the intensive remedial action was estimated to evaluate the efficiency of the intensive remedial action using analytical solution. From results of quantitative evaluation using analytical solution, it is assessed that the intensive remedial action had effectively performed with removal efficiency of 70% for the residual source mass during the remediation period. Analytical solution which can consider and quantify the impacts of partial mass reduction have been proven to be useful tools for quantifying unknown contaminant source mass and verifying dissolved concentration at the DNAPL contaminated site and evaluating the efficiency of remediation using long-term monitoring data. Acknowledgement : This subject was supported by the Korea Ministry of Environment under "GAIA project (173-092-009) and (201400540010)", R&D Project on Enviornmental Management of Geologic CO2 storage" from the KEITI (Project number:2014001810003).

Pharmacological doses of dietary curcumin increase colon epithelial cell proliferation in vivo in rats.

PubMed

Kim, Sylvia Jeewon; Hellerstein, Marc K

2007-10-01

Although curcumin has preventive actions in animal models of colon cancer, whether the mechanism of action is through anti-proliferation in normal environment is not clearly understood. Here, we studied the effects of chemopreventive doses of curcumin on the proliferation rate of colon epithelial cells (CEC), using a recently developed stable isotope-mass spectrometric method for measuring DNA synthesis rate. Adult male F344 rats were given diets containing 0, 2 and 4% curcumin for 5 weeks. 4% (2)H(2)O was given in drinking water to label DNA, after a priming bolus, for 4 days prior to sacrifice. The isotopic enrichment of the deoxyribose moiety of deoxyadenosine from DNA was measured by gas chromatography - mass spectrometry. Cell cycle analysis was performed after propidium iodide staining of CECs. Curcumin administration did not reduce but instead resulted in dose-dependent increases in CEC proliferation rate (p < 0.05) for 2% and 4% curcumin vs 0%). The length of the colon crypts and the fraction of cells in S-phase were also increased in the 2% and 4% curcumin groups (p < 0.05). Thus, pharmacological doses of curcumin increase CEC proliferation rate and pool size in normal rats. Reduction of CEC proliferation therefore cannot explain the proposed chemopreventive actions of curcumin in colon cancer.

Androgen Action via the Androgen Receptor in Neurons Within the Brain Positively Regulates Muscle Mass in Male Mice.

PubMed

Davey, Rachel A; Clarke, Michele V; Russell, Patricia K; Rana, Kesha; Seto, Jane; Roeszler, Kelly N; How, Jackie M Y; Chia, Ling Yeong; North, Kathryn; Zajac, Jeffrey D

2017-10-01

Although it is well established that exogenous androgens have anabolic effects on skeletal muscle mass in humans and mice, data from muscle-specific androgen receptor (AR) knockout (ARKO) mice indicate that myocytic expression of the AR is dispensable for hind-limb muscle mass accrual in males. To identify possible indirect actions of androgens via the AR in neurons to regulate muscle, we generated neuron-ARKO mice in which the dominant DNA binding-dependent actions of the AR are deleted in neurons of the cortex, forebrain, hypothalamus, and olfactory bulb. Serum testosterone and luteinizing hormone levels were elevated twofold in neuron-ARKO males compared with wild-type littermates due to disruption of negative feedback to the hypothalamic-pituitary-gonadal axis. Despite this increase in serum testosterone levels, which was expected to increase muscle mass, the mass of the mixed-fiber gastrocnemius (Gast) and the fast-twitch fiber extensor digitorum longus hind-limb muscles was decreased by 10% in neuron-ARKOs at 12 weeks of age, whereas muscle strength and fatigue of the Gast were unaffected. The mass of the soleus muscle, however, which consists of a high proportion of slow-twitch fibers, was unaffected in neuron-ARKOs, demonstrating a stimulatory action of androgens via the AR in neurons to increase the mass of fast-twitch hind-limb muscles. Furthermore, neuron-ARKOs displayed reductions in voluntary and involuntary physical activity by up to 60%. These data provide evidence for a role of androgens via the AR in neurons to positively regulate fast-twitch hind-limb muscle mass and physical activity in male mice. Copyright © 2017 Endocrine Society.

Epidemic Percolation Networks, Epidemic Outcomes, and Interventions

DOE PAGES

Kenah, Eben; Miller, Joel C.

2011-01-01

Epidemic percolation networks (EPNs) are directed random networks that can be used to analyze stochastic “Susceptible-Infectious-Removed” (SIR) and “Susceptible-Exposed-Infectious-Removed” (SEIR) epidemic models, unifying and generalizing previous uses of networks and branching processes to analyze mass-action and network-based S(E)IR models. This paper explains the fundamental concepts underlying the definition and use of EPNs, using them to build intuition about the final outcomes of epidemics. We then show how EPNs provide a novel and useful perspective on the design of vaccination strategies.

Epidemic Percolation Networks, Epidemic Outcomes, and Interventions

PubMed Central

Kenah, Eben; Miller, Joel C.

2011-01-01

Epidemic percolation networks (EPNs) are directed random networks that can be used to analyze stochastic “Susceptible-Infectious-Removed” (SIR) and “Susceptible-Exposed-Infectious-Removed” (SEIR) epidemic models, unifying and generalizing previous uses of networks and branching processes to analyze mass-action and network-based S(E)IR models. This paper explains the fundamental concepts underlying the definition and use of EPNs, using them to build intuition about the final outcomes of epidemics. We then show how EPNs provide a novel and useful perspective on the design of vaccination strategies. PMID:21437002

The French School System and the Universalist Metanarrative (1880-2000s): Some Reflections about So-Called Explanatory Historical Notions Such as "La Forme Scolaire"

ERIC Educational Resources Information Center

Robert, Andre D.

2013-01-01

This article aims to question the relevance of notions such as "laforme scolair"' in the account of the French state action in keeping up with the development of mass schooling, over a long historical process (from the late nineteenth century to the present day). Through its origin, this model is linked to a Universalist philosophical…

Pneumatic Variable Series Elastic Actuator.

PubMed

Zheng, Hao; Wu, Molei; Shen, Xiangrong

2016-08-01

Inspired by human motor control theory, stiffness control is highly effective in manipulation and human-interactive tasks. The implementation of stiffness control in robotic systems, however, has largely been limited to closed-loop control, and suffers from multiple issues such as limited frequency range, potential instability, and lack of contribution to energy efficiency. Variable-stiffness actuator represents a better solution, but the current designs are complex, heavy, and bulky. The approach in this paper seeks to address these issues by using pneumatic actuator as a variable series elastic actuator (VSEA), leveraging the compressibility of the working fluid. In this work, a pneumatic actuator is modeled as an elastic element with controllable stiffness and equilibrium point, both of which are functions of air masses in the two chambers. As such, for the implementation of stiffness control in a robotic system, the desired stiffness/equilibrium point can be converted to the desired chamber air masses, and a predictive pressure control approach is developed to control the timing of valve switching to obtain the desired air mass while minimizing control action. Experimental results showed that the new approach in this paper requires less expensive hardware (on-off valve instead of proportional valve), causes less control action in implementation, and provides good control performance by leveraging the inherent dynamics of the actuator.

Pneumatic Variable Series Elastic Actuator

PubMed Central

Zheng, Hao; Wu, Molei; Shen, Xiangrong

2016-01-01

Inspired by human motor control theory, stiffness control is highly effective in manipulation and human-interactive tasks. The implementation of stiffness control in robotic systems, however, has largely been limited to closed-loop control, and suffers from multiple issues such as limited frequency range, potential instability, and lack of contribution to energy efficiency. Variable-stiffness actuator represents a better solution, but the current designs are complex, heavy, and bulky. The approach in this paper seeks to address these issues by using pneumatic actuator as a variable series elastic actuator (VSEA), leveraging the compressibility of the working fluid. In this work, a pneumatic actuator is modeled as an elastic element with controllable stiffness and equilibrium point, both of which are functions of air masses in the two chambers. As such, for the implementation of stiffness control in a robotic system, the desired stiffness/equilibrium point can be converted to the desired chamber air masses, and a predictive pressure control approach is developed to control the timing of valve switching to obtain the desired air mass while minimizing control action. Experimental results showed that the new approach in this paper requires less expensive hardware (on–off valve instead of proportional valve), causes less control action in implementation, and provides good control performance by leveraging the inherent dynamics of the actuator. PMID:27354755

Heavy-Meson Spectrum Tests of the Oktay--Kronfeld Action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, Jon A.; Jang, Yong-Chull; Lee, Weonjong

2014-11-07

We present heavy-meson spectrum results obtained using the Oktay--Kronfeld (OK) action on MILC asqtad lattices. The OK action was designed to improve the heavy-quark action of the Fermilab formulation, such that heavy-quark discretization errors are reduced. The OK action includes dimension-6 and -7 operators necessary for tree-level matching to QCD through ordermore » $$\\mathrm{O}(\\Lambda^3/m_Q^3)$$ for heavy-light mesons and $$\\mathrm{O}(v^6)$$ for quarkonium, or, equivalently, through $$\\mathrm{O}(a^2)$$ with some $$\\mathrm{O}(a^3)$$ terms with Symanzik power counting. To assess the improvement, we extend previous numerical tests with heavy-meson masses by analyzing data generated on a finer ($$a \\approx 0.12\\;$$fm) lattice with the correct tadpole factors for the $$c_5$$ term in the action. We update the analyses of the inconsistency parameter and the hyperfine splittings for the rest and kinetic masses.« less

Complexity-action duality of the shock wave geometry in a massive gravity theory

NASA Astrophysics Data System (ADS)

Miao, Yan-Gang; Zhao, Long

2018-01-01

On the holographic complexity dual to the bulk action, we investigate the action growth for a shock wave geometry in a massive gravity theory within the Wheeler-DeWitt (WDW) patch at the late time limit. For a global shock wave, the graviton mass does not affect the action growth in the bulk, i.e., the complexity on the boundary, showing that the action growth (complexity) is the same for both the Einstein gravity and the massive gravity. Nevertheless, for a local shock wave that depends on transverse coordinates, the action growth (complexity) caused by the boundary disturbance (perturbation) is proportional to the butterfly velocity for the two gravity theories, but the butterfly velocity of the massive gravity theory is smaller than that of the Einstein gravity theory, indicating that the action growth (complexity) of the massive gravity is depressed by the graviton mass. In addition, we extend the black hole thermodynamics of the massive gravity and obtain the right Smarr formula.

Kinetic model of mass transfer through gas liquid interface in laser surface alloying

NASA Astrophysics Data System (ADS)

Gnedovets, A. G.; Portnov, O. M.; Smurov, I.; Flamant, G.

1997-02-01

In laser surface alloying from gas atmosphere neither surface concentration nor the flux of the alloying elements are known beforehand. They should be determined from the combined solution of heat and mass transfer equations with an account for the kinetics of interaction of a gas with a melt. Kinetic theory description of mass transfer through the gas-liquid interface is applied to the problem of laser surface alloying of iron from the atmosphere of molecular nitrogen. The activation nature of gas molecules dissociation at the surface is considered. It is shown that under pulsed-periodic laser action the concentration profiles of the alloying element have maxima situated close to the surface of the metal. The efficiency of surface alloying increases steeply under laser-plasma conditions which results in the formation of highly supersaturated gas solutions in the metal.

Analysis of an electrohydraulic aircraft control surface servo and comparison with test results

NASA Technical Reports Server (NTRS)

Edwards, J. W.

1972-01-01

An analysis of an electrohydraulic aircraft control-surface system is made in which the system is modeled as a lumped, two-mass, spring-coupled system controlled by a servo valve. Both linear and nonlinear models are developed, and the effects of hinge-moment loading are included. Transfer functions of the system and approximate literal factors of the transfer functions for several cases are presented. The damping action of dynamic pressure feedback is analyzed. Comparisons of the model responses with results from tests made on a highly resonant rudder control-surface servo indicate the adequacy of the model. The effects of variations in hinge-moment loading are illustrated.

Mesoscale atmospheric modeling for emergency response

NASA Astrophysics Data System (ADS)

Osteen, B. L.; Fast, J. D.

Atmospheric transport models for emergency response have traditionally utilized meteorological fields interpolated from sparse data to predict contaminant transport. Often these fields are adjusted to satisfy constraints derived from the governing equations of geophysical fluid dynamics, e.g. mass continuity. Gaussian concentration distributions or stochastic models are then used to represent turbulent diffusion of a contaminant in the diagnosed meteorological fields. The popularity of these models derives from their relative simplicity, ability to make reasonable short-term predictions, and, most important, execution speed. The ability to generate a transport prediction for an accidental release from the Savannah River Site in a time frame which will allow protective action to be taken is essential in an emergency response operation.

A model for HIV/AIDS pandemic with optimal control

NASA Astrophysics Data System (ADS)

Sule, Amiru; Abdullah, Farah Aini

2015-05-01

Human immunodeficiency virus and acquired immune deficiency syndrome (HIV/AIDS) is pandemic. It has affected nearly 60 million people since the detection of the disease in 1981 to date. In this paper basic deterministic HIV/AIDS model with mass action incidence function are developed. Stability analysis is carried out. And the disease free equilibrium of the basic model was found to be locally asymptotically stable whenever the threshold parameter (RO) value is less than one, and unstable otherwise. The model is extended by introducing two optimal control strategies namely, CD4 counts and treatment for the infective using optimal control theory. Numerical simulation was carried out in order to illustrate the analytic results.

The Relationship Between School Holidays and Transmission of Influenza in England and Wales.

PubMed

Jackson, Charlotte; Vynnycky, Emilia; Mangtani, Punam

2016-11-01

School closure is often considered as an influenza control measure, but its effects on transmission are poorly understood. We used 2 approaches to estimate how school holidays affect the contact parameter (the per capita rate of contact sufficient for infection transmission) for influenza using primary care data from England and Wales (1967-2000). Firstly, we fitted an age-structured susceptible-infectious-recovered model to each year's data to estimate the proportional change in the contact parameter during school holidays as compared with termtime. Secondly, we calculated the percentage difference in the contact parameter between holidays and termtime from weekly values of the contact parameter, estimated directly from simple mass-action models. Estimates were combined using random-effects meta-analysis, where appropriate. From fitting to the data, the difference in the contact parameter among children aged 5-14 years during holidays as compared with termtime ranged from a 36% reduction to a 17% increase; estimates were too heterogeneous for meta-analysis. Based on the simple mass-action model, the contact parameter was 17% (95% confidence interval: 10, 25) lower during holidays than during termtime. Results were robust to the assumed proportions of infections that were reported and individuals who were susceptible when the influenza season started. We conclude that school closure may reduce transmission during influenza outbreaks. © The Author 2016. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Wave-induced hydraulic forces on submerged aquatic plants in shallow lakes.

PubMed

Schutten, J; Dainty, J; Davy, A J

2004-03-01

Hydraulic pulling forces arising from wave action are likely to limit the presence of freshwater macrophytes in shallow lakes, particularly those with soft sediments. The aim of this study was to develop and test experimentally simple models, based on linear wave theory for deep water, to predict such forces on individual shoots. Models were derived theoretically from the action of the vertical component of the orbital velocity of the waves on shoot size. Alternative shoot-size descriptors (plan-form area or dry mass) and alternative distributions of the shoot material along its length (cylinder or inverted cone) were examined. Models were tested experimentally in a flume that generated sinusoidal waves which lasted 1 s and were up to 0.2 m high. Hydraulic pulling forces were measured on plastic replicas of Elodea sp. and on six species of real plants with varying morphology (Ceratophyllum demersum, Chara intermedia, Elodea canadensis, Myriophyllum spicatum, Potamogeton natans and Potamogeton obtusifolius). Measurements on the plastic replicas confirmed predicted relationships between force and wave phase, wave height and plant submergence depth. Predicted and measured forces were linearly related over all combinations of wave height and submergence depth. Measured forces on real plants were linearly related to theoretically derived predictors of the hydraulic forces (integrals of the products of the vertical orbital velocity raised to the power 1.5 and shoot size). The general applicability of the simplified wave equations used was confirmed. Overall, dry mass and plan-form area performed similarly well as shoot-size descriptors, as did the conical or cylindrical models of shoot distribution. The utility of the modelling approach in predicting hydraulic pulling forces from relatively simple plant and environmental measurements was validated over a wide range of forces, plant sizes and species.

Un-renormalized classical electromagnetism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ibison, Michael

2006-02-15

This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. However, the direct-action approach ultimately failed in that respect because its initial exclusion of self-action was later found to be untenable in the relativistic domain. Pursing the same end, this paper examines instead a version of electromagnetism wherein mechanical action is excluded and self-action is retained. It is shown that the resulting theory is effectively interacting due to the presence of infinitemore » forces. A vehicle for the investigation is a pair of classical point charges in a positronium-like arrangement for which the orbits are found to be self-sustaining and naturally quantized.« less

A research on Performance Efficiency of Rubber Metal Support Structures

NASA Astrophysics Data System (ADS)

Mkrtychev, Oleg V.; Bunov, Artem A.

2017-11-01

The paper scrutinizes structural behavior of lead rubber bearings by a Chinese manufacturer subjected to a single-component seismic action. Several problems were solved using specialized software complexes, which conducted forth integration of motion equations through the explicit method or response spectrum method. Depending on the calculation method, the diagram of the bearing performance was assumed to be either an actual diagram approximated by an idealized non-linear diagram or an idealized linear diagram with a specific stiffness. The computational model was assumed to be a single-mass oscillator with a lumped mass. The effort undertaken facilitated the investigation of the patterns of horizontal displacement of the bearing top relative to bottom caused by earthquakes modeled as accelerograms with different spectral compositions. The behavior of the support structure was benchmarked against similar supports by another manufacturer. The paper presents the outcomes of the research effort and draws conclusions about the efficiency of using the bearings of this particular type and model.

23 CFR 810.208 - Action by the Federal Highway Administrator.

Code of Federal Regulations, 2011 CFR

2011-04-01

... TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Making Highway Rights-of-Way Available for Mass... may authorize the State to make available to the publicly-owned mass transit authority the land needed...

Using immersive simulation for training first responders for mass casualty incidents.

PubMed

Wilkerson, William; Avstreih, Dan; Gruppen, Larry; Beier, Klaus-Peter; Woolliscroft, James

2008-11-01

A descriptive study was performed to better understand the possible utility of immersive virtual reality simulation for training first responders in a mass casualty event. Utilizing a virtual reality cave automatic virtual environment (CAVE) and high-fidelity human patient simulator (HPS), a group of experts modeled a football stadium that experienced a terrorist explosion during a football game. Avatars (virtual patients) were developed by expert consensus that demonstrated a spectrum of injuries ranging from death to minor lacerations. A group of paramedics was assessed by observation for decisions made and action taken. A critical action checklist was created and used for direct observation and viewing videotaped recordings. Of the 12 participants, only 35.7% identified the type of incident they encountered. None identified a secondary device that was easily visible. All participants were enthusiastic about the simulation and provided valuable comments and insights. Learner feedback and expert performance review suggests that immersive training in a virtual environment has the potential to be a powerful tool to train first responders for high-acuity, low-frequency events, such as a terrorist attack.

The Acetyl Group Buffering Action of Carnitine Acetyltransferase Offsets Macronutrient-Induced Lysine Acetylation of Mitochondrial Proteins.

PubMed

Davies, Michael N; Kjalarsdottir, Lilja; Thompson, J Will; Dubois, Laura G; Stevens, Robert D; Ilkayeva, Olga R; Brosnan, M Julia; Rolph, Timothy P; Grimsrud, Paul A; Muoio, Deborah M

2016-01-12

Lysine acetylation (AcK), a posttranslational modification wherein a two-carbon acetyl group binds covalently to a lysine residue, occurs prominently on mitochondrial proteins and has been linked to metabolic dysfunction. An emergent theory suggests mitochondrial AcK occurs via mass action rather than targeted catalysis. To test this hypothesis, we performed mass spectrometry-based acetylproteomic analyses of quadriceps muscles from mice with skeletal muscle-specific deficiency of carnitine acetyltransferase (CrAT), an enzyme that buffers the mitochondrial acetyl-CoA pool by converting short-chain acyl-CoAs to their membrane permeant acylcarnitine counterparts. CrAT deficiency increased tissue acetyl-CoA levels and susceptibility to diet-induced AcK of broad-ranging mitochondrial proteins, coincident with diminished whole body glucose control. Sub-compartment acetylproteome analyses of muscles from obese mice and humans showed remarkable overrepresentation of mitochondrial matrix proteins. These findings reveal roles for CrAT and L-carnitine in modulating the muscle acetylproteome and provide strong experimental evidence favoring the nonenzymatic carbon pressure model of mitochondrial AcK. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The Acetyl Group Buffering Action of Carnitine Acetyltransferase Offsets Macronutrient-induced Lysine Acetylation of Mitochondrial Proteins

PubMed Central

Davies, Michael N.; Kjalarsdottir, Lilja; Thompson, J. Will; Dubois, Laura G.; Stevens, Robert D.; Ilkayeva, Olga R.; Brosnan, M. Julia; Rolph, Timothy P.; Grimsrud, Paul A.; Muoio, Deborah M.

2016-01-01

Lysine acetylation (AcK), a posttranslational modification wherein a two-carbon acetyl group binds covalently to a lysine residue, occurs prominently on mitochondrial proteins and has been linked to metabolic dysfunction. An emergent theory suggests mitochondrial AcK occurs via mass action rather than targeted catalysis. To test this hypothesis we performed mass spectrometry-based acetylproteomic analyses of quadriceps muscles from mice with skeletal muscle-specific deficiency of carnitine acetyltransferase (CrAT), an enzyme that buffers the mitochondrial acetyl-CoA pool by converting short-chain acyl-CoAs to their membrane permeant acylcarnitine counterparts. CrAT deficiency increased tissue acetyl-CoA levels and susceptibility to diet-induced AcK of broad-ranging mitochondrial proteins, coincident with diminished whole body glucose control. Sub-compartment acetylproteome analyses of muscles from obese mice and humans showed remarkable overrepresentation of mitochondrial matrix proteins. These findings reveal roles for CrAT and L-carnitine in modulating the muscle acetylproteome and provide strong experimental evidence favoring the nonenzymatic carbon pressure model of mitochondrial AcK. PMID:26748706

Semi-Analytic Galaxies - I. Synthesis of environmental and star-forming regulation mechanisms

NASA Astrophysics Data System (ADS)

Cora, Sofía A.; Vega-Martínez, Cristian A.; Hough, Tomás; Ruiz, Andrés N.; Orsi, Álvaro; Muñoz Arancibia, Alejandra M.; Gargiulo, Ignacio D.; Collacchioni, Florencia; Padilla, Nelson D.; Gottlöber, Stefan; Yepes, Gustavo

2018-05-01

We present results from the semi-analytic model of galaxy formation SAG applied on the MULTIDARK simulation MDPL2. SAG features an updated supernova (SN) feedback scheme and a robust modelling of the environmental effects on satellite galaxies. This incorporates a gradual starvation of the hot gas halo driven by the action of ram pressure stripping (RPS), that can affect the cold gas disc, and tidal stripping (TS), which can act on all baryonic components. Galaxy orbits of orphan satellites are integrated providing adequate positions and velocities for the estimation of RPS and TS. The star formation history and stellar mass assembly of galaxies are sensitive to the redshift dependence implemented in the SN feedback model. We discuss a variant of our model that allows to reconcile the predicted star formation rate density at z ≳ 3 with the observed one, at the expense of an excess in the faint end of the stellar mass function at z = 2. The fractions of passive galaxies as a function of stellar mass, halo mass and the halo-centric distances are consistent with observational measurements. The model also reproduces the evolution of the main sequence of star forming central and satellite galaxies. The similarity between them is a result of the gradual starvation of the hot gas halo suffered by satellites, in which RPS plays a dominant role. RPS of the cold gas does not affect the fraction of quenched satellites but it contributes to reach the right atomic hydrogen gas content for more massive satellites (M⋆ ≳ 1010 M⊙).

The role of educational trainings in the diffusion of smart metering platforms: An agent-based modeling approach

NASA Astrophysics Data System (ADS)

Weron, Tomasz; Kowalska-Pyzalska, Anna; Weron, Rafał

2018-09-01

Using an agent-based modeling approach we examine the impact of educational programs and trainings on the diffusion of smart metering platforms (SMPs). We also investigate how social responses, like conformity or independence, mass-media advertising as well as opinion stability impact the transition from predecisional and preactional behavioral stages (opinion formation) to actional and postactional stages (decision-making) of individual electricity consumers. We find that mass-media advertising (i.e., a global external field) and educational trainings (i.e., a local external field) lead to similar, though not identical adoption rates. Secondly, that spatially concentrated 'group' trainings are never worse than randomly scattered ones, and for a certain range of parameters are significantly better. Finally, that by manipulating the time required by an agent to make a decision, e.g., through promotions, we can speed up or slow down the diffusion of SMPs.

Semileptonic B-meson decays to light pseudoscalar mesons on the HISQ ensembles

NASA Astrophysics Data System (ADS)

Gelzer, Zechariah; Bernard, C.; Tar, C. De; El-Khadra, AX; Gámiz, E.; Gottlieb, Steven; Kronfeld, Andreas S.; Liu, Yuzhi; Meurice, Y.; Simone, J. N.; Toussaint, D.; Water, R. S. Van de; Zhou, R.

2018-03-01

We report the status of an ongoing lattice-QCD calculation of form factors for exclusive semileptonic decays of B mesons with both charged currents (B → πlv, Bs → Klv) and neutral currents (B → πl+l-, B → Kl+l-). The results are important for constraining or revealing physics beyond the Standard Model. This work uses MILC's (2+1 + 1)-flavor ensembles with the HISQ action for the sea and light valence quarks and the clover action in the Fermilab interpretation for the b quark. Simulations are carried out at three lattice spacings down to 0.088 fm, with both physical and unphysical sea-quark masses. We present preliminary results for correlation-function fits.

Improving the theoretical prediction for the Bs - B̅s width difference: matrix elements of next-to-leading order ΔB = 2 operators

NASA Astrophysics Data System (ADS)

Davies, Christine; Harrison, Judd; Lepage, G. Peter; Monahan, Christopher; Shigemitsu, Junko; Wingate, Matthew

2018-03-01

We present lattice QCD results for the matrix elements of R2 and other dimension-7, ΔB = 2 operators relevant for calculations of Δs, the Bs - B̅s width difference. We have computed correlation functions using 5 ensembles of the MILC Collaboration's 2+1 + 1-flavour gauge field configurations, spanning 3 lattice spacings and light sea quarks masses down to the physical point. The HISQ action is used for the valence strange quarks, and the NRQCD action is used for the bottom quarks. Once our analysis is complete, the theoretical uncertainty in the Standard Model prediction for ΔΓs will be substantially reduced.

Charmed bottom baryon spectroscopy from lattice QCD

DOE PAGES

Brown, Zachary S.; Detmold, William; Meinel, Stefan; ...

2014-11-19

In this study, we calculate the masses of baryons containing one, two, or three heavy quarks using lattice QCD. We consider all possible combinations of charm and bottom quarks, and compute a total of 36 different states with J P = 1/2 + and J P = 3/2 +. We use domain-wall fermions for the up, down, and strange quarks, a relativistic heavy-quark action for the charm quarks, and nonrelativistic QCD for the bottom quarks. Our analysis includes results from two different lattice spacings and seven different pion masses. We perform extrapolations of the baryon masses to the continuum limitmore » and to the physical pion mass using SU(4|2) heavy-hadron chiral perturbation theory including 1/m Q and finite-volume effects. For the 14 singly heavy baryons that have already been observed, our results agree with the experimental values within the uncertainties. We compare our predictions for the hitherto unobserved states with other lattice calculations and quark-model studies.« less

Bessel functions in mass action modeling of memories and remembrances

NASA Astrophysics Data System (ADS)

Freeman, Walter J.; Capolupo, Antonio; Kozma, Robert; Olivares del Campo, Andrés; Vitiello, Giuseppe

2015-10-01

Data from experimental observations of a class of neurological processes (Freeman K-sets) present functional distribution reproducing Bessel function behavior. We model such processes with couples of damped/amplified oscillators which provide time dependent representation of Bessel equation. The root loci of poles and zeros conform to solutions of K-sets. Some light is shed on the problem of filling the gap between the cellular level dynamics and the brain functional activity. Breakdown of time-reversal symmetry is related with the cortex thermodynamic features. This provides a possible mechanism to deduce lifetime of recorded memory.

Sustaining Action and Optimizing Entropy: Coupling Efficiency for Energy and the Sustainability of Global Ecosystems

ERIC Educational Resources Information Center

Rose, Michael T.; Crossan, Angus N.; Kennedy, Ivan R.

2008-01-01

Consideration of the property of action is proposed to provide a more meaningful definition of efficient energy use and sustainable production in ecosystems. Action has physical dimensions similar to angular momentum, its magnitude varying with mass, spatial configuration and relative motion. In this article, the relationship of action to…

Recent advances in secondary ion mass spectrometry of solid acid catalysts: large zeolite crystals under bombardment.

PubMed

Hofmann, Jan P; Rohnke, Marcus; Weckhuysen, Bert M

2014-03-28

This Perspective aims to inform the heterogeneous catalysis and materials science community about the recent advances in Time-of-Flight-Secondary Ion Mass Spectrometry (ToF-SIMS) to characterize catalytic solids by taking large model H-ZSM-5 zeolite crystals as a showcase system. SIMS-based techniques have been explored in the 1980-1990's to study porous catalyst materials but, due to their limited spectral and spatiotemporal resolution, there was no real major breakthrough at that time. The technical advancements in SIMS instruments, namely improved ion gun design and new mass analyser concepts, nowadays allow for a much more detailed analysis of surface species relevant to catalytic action. Imaging with high mass and lateral resolution, determination of fragment ion patterns, novel sputter ion concepts as well as new mass analysers (e.g. ToF, FTICR) are just a few novelties, which will lead to new fundamental insight from SIMS analysis of heterogeneous catalysts. The Perspective article ends with an outlook on instrumental innovations and their potential use for catalytic systems other than zeolite crystals.

76 FR 82322 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Mass Layoff...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-30

... for OMB Review; Comment Request; Mass Layoff Statistics Program ACTION: Notice. SUMMARY: The... request (ICR) titled, ``Mass Layoff Statistics Program,'' to the Office of Management and Budget (OMB) for... Statistics (BLS). Title of Collection: Mass Layoff Statistics Program. OMB Control Number: 1220-0090...

Numerical algebraic geometry for model selection and its application to the life sciences

PubMed Central

Gross, Elizabeth; Davis, Brent; Ho, Kenneth L.; Bates, Daniel J.

2016-01-01

Researchers working with mathematical models are often confronted by the related problems of parameter estimation, model validation and model selection. These are all optimization problems, well known to be challenging due to nonlinearity, non-convexity and multiple local optima. Furthermore, the challenges are compounded when only partial data are available. Here, we consider polynomial models (e.g. mass-action chemical reaction networks at steady state) and describe a framework for their analysis based on optimization using numerical algebraic geometry. Specifically, we use probability-one polynomial homotopy continuation methods to compute all critical points of the objective function, then filter to recover the global optima. Our approach exploits the geometrical structures relating models and data, and we demonstrate its utility on examples from cell signalling, synthetic biology and epidemiology. PMID:27733697

High-Viscosity Oil Filtration in the Pool Under Thermal Action

NASA Astrophysics Data System (ADS)

Shagapov, V. Sh.; Yumagulova, Yu. A.; Gizzatullina, A. A.

2018-05-01

We have developed a mathematical model and constructed numerical solutions of the problem of heating a high-viscosity oil pool through one horizontal well or a system of wells and have shown the possibility of their further operation until the limiting profitable discharge of oil is attained. The expenditure of heat in heating the oil pool, the evolution of discharge of oil, and the mass of extracted oil over the considered period have been considered.

Quantifying Differences in the Impact of Variable Chemistry on Equilibrium Uranium(VI) Adsorption Properties of Aquifer Sediments

PubMed Central

2011-01-01

Uranium adsorption–desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500–1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO22+ + 2CO32- = >SOUO2(CO3HCO3)2–, provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logKc) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logKc values. Using this approach, logKc values for seven sediment samples were not significantly different. However, a significant difference in adsorption properties between one sediment sample and the fines (<0.063 mm) of another could be demonstrated despite the fines requiring a different reaction stoichiometry. Estimates of logKc uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors. PMID:21923109

Quantifying differences in the impact of variable chemistry on equilibrium Uranium(VI) adsorption properties of aquifer sediments.

PubMed

Stoliker, Deborah L; Kent, Douglas B; Zachara, John M

2011-10-15

Uranium adsorption-desorption on sediment samples collected from the Hanford 300-Area, Richland, WA varied extensively over a range of field-relevant chemical conditions, complicating assessment of possible differences in equilibrium adsorption properties. Adsorption equilibrium was achieved in 500-1000 h although dissolved uranium concentrations increased over thousands of hours owing to changes in aqueous chemical composition driven by sediment-water reactions. A nonelectrostatic surface complexation reaction, >SOH + UO₂²⁺ + 2CO₃²⁻ = >SOUO₂(CO₃HCO₃)²⁻, provided the best fit to experimental data for each sediment sample resulting in a range of conditional equilibrium constants (logK(c)) from 21.49 to 21.76. Potential differences in uranium adsorption properties could be assessed in plots based on the generalized mass-action expressions yielding linear trends displaced vertically by differences in logK(c) values. Using this approach, logK(c) values for seven sediment samples were not significantly different. However, a significant difference in adsorption properties between one sediment sample and the fines (< 0.063 mm) of another could be demonstrated despite the fines requiring a different reaction stoichiometry. Estimates of logK(c) uncertainty were improved by capturing all data points within experimental errors. The mass-action expression plots demonstrate that applying models outside the range of conditions used in model calibration greatly increases potential errors.

Emergent gravity from a mass deformation in warped spacetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gherghetta, Tony; Peloso, Marco; Poppitz, Erich

2005-11-15

We consider a deformation of five-dimensional warped gravity with bulk and boundary mass terms to quadratic order in the action. We show that massless zero modes occur for special choices of the masses. The tensor zero mode is a smooth deformation of the Randall-Sundrum graviton wave function and can be localized anywhere in the bulk. There is also a vector zero mode with similar localization properties, which is decoupled from conserved sources at tree level. Interestingly, there are no scalar modes, and the model is ghost-free at the linearized level. When the tensor zero mode is localized near the IRmore » brane, the dual interpretation is a composite graviton describing an emergent (induced) theory of gravity at the IR scale. In this case Newton's law of gravity changes to a new power law below the millimeter scale, with an exponent that can even be irrational.« less

Action-based Dynamical Modeling for the Milky Way Disk: The Influence of Spiral Arms

NASA Astrophysics Data System (ADS)

Trick, Wilma H.; Bovy, Jo; D'Onghia, Elena; Rix, Hans-Walter

2017-04-01

RoadMapping is a dynamical modeling machinery developed to constrain the Milky Way’s (MW) gravitational potential by simultaneously fitting an axisymmetric parametrized potential and an action-based orbit distribution function (DF) to discrete 6D phase-space measurements of stars in the Galactic disk. In this work, we demonstrate RoadMapping's robustness in the presence of spiral arms by modeling data drawn from an N-body simulation snapshot of a disk-dominated galaxy of MW mass with strong spiral arms (but no bar), exploring survey volumes with radii 500 {pc}≤slant {r}\\max ≤slant 5 {kpc}. The potential constraints are very robust, even though we use a simple action-based DF, the quasi-isothermal DF. The best-fit RoadMapping model always recovers the correct gravitational forces where most of the stars that entered the analysis are located, even for small volumes. For data from large survey volumes, RoadMapping finds axisymmetric models that average well over the spiral arms. Unsurprisingly, the models are slightly biased by the excess of stars in the spiral arms. Gravitational potential models derived from survey volumes with at least {r}\\max =3 {kpc} can be reliably extrapolated to larger volumes. However, a large radial survey extent, {r}\\max ˜ 5 {kpc}, is needed to correctly recover the halo scale length. In general, the recovery and extrapolability of potentials inferred from data sets that were drawn from inter-arm regions appear to be better than those of data sets drawn from spiral arms. Our analysis implies that building axisymmetric models for the Galaxy with upcoming Gaia data will lead to sensible and robust approximations of the MW’s potential.

Interest Convergence or Divergence? A Critical Race Analysis of Asian Americans, Meritocracy, and Critical Mass in the Affirmative Action Debate

ERIC Educational Resources Information Center

Park, Julie J.; Liu, Amy

2014-01-01

We use the Critical Race Theory frameworks of interest convergence and divergence to critique the anti-affirmative action movement's co-option of Asian Americans. Past discussions of affirmative action and Asian Americans mainly concentrate on how Asian Americans are affected by affirmative action, whether positively or negatively. We demonstrate…

Optimum periodicity of repeated contractile actions applied in mass transport

NASA Astrophysics Data System (ADS)

Ahn, Sungsook; Lee, Sang Joon

2015-01-01

Dynamically repeated periodic patterns are abundant in natural and artificial systems, such as tides, heart beats, stock prices, and the like. The characteristic repeatability and periodicity are expected to be optimized in effective system-specific functions. In this study, such optimum periodicity is experimentally evaluated in terms of effective mass transport using one-valve and multi-valve systems working in contractile fluid flows. A set of nanoscale gating functions is utilized, operating in nanocomposite networks through which permeates selectively pass under characteristic contractile actions. Optimized contractile periodicity exists for effective energy impartment to flow in a one-valve system. In the sequential contractile actions for a multi-valve system, synchronization with the fluid flow is critical for effective mass transport. This study provides fundamental understanding on the various repeated periodic patterns and dynamic repeatability occurring in nature and mechanical systems, which are useful for broad applications.

Combinatoric analysis of heterogeneous stochastic self-assembly.

PubMed

D'Orsogna, Maria R; Zhao, Bingyu; Berenji, Bijan; Chou, Tom

2013-09-28

We analyze a fully stochastic model of heterogeneous nucleation and self-assembly in a closed system with a fixed total particle number M, and a fixed number of seeds Ns. Each seed can bind a maximum of N particles. A discrete master equation for the probability distribution of the cluster sizes is derived and the corresponding cluster concentrations are found using kinetic Monte-Carlo simulations in terms of the density of seeds, the total mass, and the maximum cluster size. In the limit of slow detachment, we also find new analytic expressions and recursion relations for the cluster densities at intermediate times and at equilibrium. Our analytic and numerical findings are compared with those obtained from classical mass-action equations and the discrepancies between the two approaches analyzed.

Update on Heavy-Meson Spectrum Tests of the Oktay--Kronfeld Action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, Jon A.; Jang, Yong-Chull; Lee, Weonjong

2016-01-18

We present updated results of a numerical improvement test with heavy-meson spectrum for the Oktay--Kronfeld (OK) action. The OK action is an extension of the Fermilab improvement program for massive Wilson fermions including all dimension-six and some dimension-seven bilinear terms. Improvement terms are truncated by HQET power counting atmore » $$\\mathrm{O}(\\Lambda^3/m_Q^3)$$ for heavy-light systems, and by NRQCD power counting at $$\\mathrm{O}(v^6)$$ for quarkonium. They suffice for tree-level matching to QCD to the given order in the power-counting schemes. To assess the improvement, we generate new data with the OK and Fermilab action that covers both charm and bottom quark mass regions on a MILC coarse $$(a \\approx 0.12~\\text{fm})$$ $2+1$ flavor, asqtad-staggered ensemble. We update the analyses of the inconsistency quantity and the hyperfine splittings for the rest and kinetic masses. With one exception, the results clearly show that the OK action significantly reduces heavy-quark discretization effects in the meson spectrum. The exception is the hyperfine splitting of the heavy-light system near the $$B_s$$ meson mass, where statistics are too low to draw a firm conclusion, despite promising results.« less

Cato Guldberg and Peter Waage, the history of the Law of Mass Action, and its relevance to clinical pharmacology.

PubMed

Ferner, Robin E; Aronson, Jeffrey K

2016-01-01

We have traced the historical link between the Law of Mass Action and clinical pharmacology. The Law evolved from the work of the French chemist Claude Louis Berthollet, was first formulated by Cato Guldberg and Peter Waage in 1864 and later clarified by the Dutch chemist Jacobus van 't Hoff in 1877. It has profoundly influenced our qualitative and quantitative understanding of a number of physiological and pharmacological phenomena. According to the Law of Mass Action, the velocity of a chemical reaction depends on the concentrations of the reactants. At equilibrium the concentrations of the chemicals involved bear a constant relation to each other, described by the equilibrium constant, K. The Law of Mass Action is relevant to various physiological and pharmacological concepts, including concentration-effect curves, dose-response curves, and ligand-receptor binding curves, all of which are important in describing the pharmacological actions of medications, the Langmuir adsorption isotherm, which describes the binding of medications to proteins, activation curves for transmembrane ion transport, enzyme inhibition and the Henderson-Hasselbalch equation, which describes the relation between pH, as a measure of acidity and the concentrations of the contributory acids and bases. Guldberg and Waage recognized the importance of dynamic equilibrium, while others failed to do so. Their ideas, over 150 years old, are embedded in and still relevant to clinical pharmacology. Here we explain the ideas and in a subsequent paper show how they are relevant to understanding adverse drug reactions. © 2015 The British Pharmacological Society.

A sensorimotor theory of temporal tracking and beat induction.

PubMed

Todd, N P McAngus; Lee, C S; O'Boyle, D J

2002-02-01

In this paper, we develop a theory of the neurobiological basis of temporal tracking and beat induction as a form of sensory-guided action. We propose three principal components for the neurological architecture of temporal tracking: (1) the central auditory system, which represents the temporal information in the input signal in the form of a modulation power spectrum; (2) the musculoskeletal system, which carries out the action and (3) a controller, in the form of a parieto-cerebellar-frontal loop, which carries out the synchronisation between input and output by means of an internal model of the musculoskeletal dynamics. The theory is implemented in the form of a computational algorithm which takes sound samples as input and synchronises a simple linear mass-spring-damper system to simulate audio-motor synchronisation. The model may be applied to both the tracking of isochronous click sequences and beat induction in rhythmic music or speech, and also accounts for the approximate Weberian property of timing.

Calculation of electronic transport coefficients of Ag and Au plasma.

PubMed

Apfelbaum, E M

2011-12-01

The thermoelectric transport coefficients of silver and gold plasma have been calculated within the relaxation-time approximation. We considered temperatures of 10-100 kK and densities of ρ

Grey-box modelling of aeration tank settling.

PubMed

Bechman, Henrik; Nielsen, Marinus K; Poulsen, Niels Kjølstad; Madsen, Henrik

2002-04-01

A model of the concentrations of suspended solids (SS) in the aeration tanks and in the effluent from these during Aeration tank settling (ATS) operation is established. The model is based on simple SS mass balances, a model of the sludge settling and a simple model of how the SS concentration in the effluent from the aeration tanks depends on the actual concentrations in the tanks and the sludge blanket depth. The model is formulated in continuous time by means of stochastic differential equations with discrete-time observations. The parameters of the model are estimated using a maximum likelihood method from data from an alternating BioDenipho waste water treatment plant (WWTP). The model is an important tool for analyzing ATS operation and for selecting the appropriate control actions during ATS, as the model can be used to predict the SS amounts in the aeration tanks as well as in the effluent from the aeration tanks.

Chemical networks with inflows and outflows: a positive linear differential inclusions approach.

PubMed

Angeli, David; De Leenheer, Patrick; Sontag, Eduardo D

2009-01-01

Certain mass-action kinetics models of biochemical reaction networks, although described by nonlinear differential equations, may be partially viewed as state-dependent linear time-varying systems, which in turn may be modeled by convex compact valued positive linear differential inclusions. A result is provided on asymptotic stability of such inclusions, and applied to a ubiquitous biochemical reaction network with inflows and outflows, known as the futile cycle. We also provide a characterization of exponential stability of general homogeneous switched systems which is not only of interest in itself, but also plays a role in the analysis of the futile cycle. 2009 American Institute of Chemical Engineers

Physical Regulation of the Self-Assembly of Tobacco Mosaic Virus Coat Protein

PubMed Central

Kegel, Willem K.; van der Schoot, Paul

2006-01-01

We present a statistical mechanical model based on the principle of mass action that explains the main features of the in vitro aggregation behavior of the coat protein of tobacco mosaic virus (TMV). By comparing our model to experimentally obtained stability diagrams, titration experiments, and calorimetric data, we pin down three competing factors that regulate the transitions between the different kinds of aggregated state of the coat protein. These are hydrophobic interactions, electrostatic interactions, and the formation of so-called “Caspar” carboxylate pairs. We suggest that these factors could be universal and relevant to a large class of virus coat proteins. PMID:16731551

Cellerator: extending a computer algebra system to include biochemical arrows for signal transduction simulations

NASA Technical Reports Server (NTRS)

Shapiro, Bruce E.; Levchenko, Andre; Meyerowitz, Elliot M.; Wold, Barbara J.; Mjolsness, Eric D.

2003-01-01

Cellerator describes single and multi-cellular signal transduction networks (STN) with a compact, optionally palette-driven, arrow-based notation to represent biochemical reactions and transcriptional activation. Multi-compartment systems are represented as graphs with STNs embedded in each node. Interactions include mass-action, enzymatic, allosteric and connectionist models. Reactions are translated into differential equations and can be solved numerically to generate predictive time courses or output as systems of equations that can be read by other programs. Cellerator simulations are fully extensible and portable to any operating system that supports Mathematica, and can be indefinitely nested within larger data structures to produce highly scaleable models.

Using a Marginal Structural Model to Design a Theory-Based Mass Media Campaign.

PubMed

Nishiuchi, Hiromu; Taguri, Masataka; Ishikawa, Yoshiki

2016-01-01

The essential first step in the development of mass media health campaigns is to identify specific beliefs of the target audience. The challenge is to prioritize suitable beliefs derived from behavioral theory. The purpose of this study was to identify suitable beliefs to target in a mass media campaign to change behavior using a new method to estimate the possible effect size of a small set of beliefs. Data were drawn from the 2010 Japanese Young Female Smoker Survey (n = 500), conducted by the Japanese Ministry of Health, Labor and Welfare. Survey measures included intention to quit smoking, psychological beliefs (attitude, norms, and perceived control) based on the theory of planned behavior and socioeconomic status (age, education, household income, and marital status). To identify suitable candidate beliefs for a mass media health campaign, we estimated the possible effect size required to change the intention to quit smoking among the population of young Japanese women using the population attributable fraction from a marginal structural model. Thirteen percent of study participants intended to quit smoking. The marginal structural model estimated a population attributable fraction of 47 psychological beliefs (21 attitudes, 6 norms, and 19 perceived controls) after controlling for socioeconomic status. The belief, "I could quit smoking if my husband or significant other recommended it" suggested a promising target for a mass media campaign (population attributable fraction = 0.12, 95% CI = 0.02-0.23). Messages targeting this belief could possibly improve intention rates by up to 12% among this population. The analysis also suggested the potential for regulatory action. This study proposed a method by which campaign planners can develop theory-based mass communication strategies to change health behaviors at the population level. This method might contribute to improving the quality of future mass health communication strategies and further research is needed.

On the dynamics of interaction between a moving mass and an infinite one-dimensional elastic structure at the stability limit

NASA Astrophysics Data System (ADS)

Mazilu, Traian; Dumitriu, Mădălina; Tudorache, Cristina

2011-07-01

The paper herein deals with the study of the dynamic behaviour generated by the instability of the vibration of a loaded mass, uniformly moving along an Euler-Bernoulli beam on a viscoelastic foundation, induced by the anomalous Doppler waves excited in the beam. This issue is relevant for the case of modern trains travelling along a track with soft soil when the trains speed exceeds the phase velocity of the waves induced in the track. The model corresponds to a railway vehicle reduced to a loaded wheel running along a (half) track. The beam takes account of the bending stiffness of the rail and the mass of the track, including the mass of the rail, semi-sleepers and half of the ballast layer, where the viscoelastic foundation represents the subgrade. The model includes the wheel/rail Hertzian contact and it allows the simulation of the possibility of contact loss. The nonlinear equations of motion are integrated using a numerical approach based on the Green's function method. When the vibration becomes unstable, the system evolution is a limit cycle characterised by a succession of shocks, due to the action of two opposite factors: the anomalous Doppler waves that pump energy at the interface between the moving mass and the beam, thus forcing the mass to take off, and the static load that push the mass downwards. The frequency of the shocks increases at higher velocity and the magnitude of the impact force decreases; the most dangerous velocity is the critical one, which represents the stability limit of the linear approximation of the motion equations. The transient behaviour that precedes the limit cycle appearance is being analysed. The Hertzian contact influences the time history of the limit cycle and the magnitude of the impact force and, therefore, it is essential to be included in the model. To the authors' knowledge, this problem has never been dealt with.

Using a Marginal Structural Model to Design a Theory-Based Mass Media Campaign

PubMed Central

Taguri, Masataka; Ishikawa, Yoshiki

2016-01-01

Background The essential first step in the development of mass media health campaigns is to identify specific beliefs of the target audience. The challenge is to prioritize suitable beliefs derived from behavioral theory. The purpose of this study was to identify suitable beliefs to target in a mass media campaign to change behavior using a new method to estimate the possible effect size of a small set of beliefs. Methods Data were drawn from the 2010 Japanese Young Female Smoker Survey (n = 500), conducted by the Japanese Ministry of Health, Labor and Welfare. Survey measures included intention to quit smoking, psychological beliefs (attitude, norms, and perceived control) based on the theory of planned behavior and socioeconomic status (age, education, household income, and marital status). To identify suitable candidate beliefs for a mass media health campaign, we estimated the possible effect size required to change the intention to quit smoking among the population of young Japanese women using the population attributable fraction from a marginal structural model. Results Thirteen percent of study participants intended to quit smoking. The marginal structural model estimated a population attributable fraction of 47 psychological beliefs (21 attitudes, 6 norms, and 19 perceived controls) after controlling for socioeconomic status. The belief, “I could quit smoking if my husband or significant other recommended it” suggested a promising target for a mass media campaign (population attributable fraction = 0.12, 95% CI = 0.02–0.23). Messages targeting this belief could possibly improve intention rates by up to 12% among this population. The analysis also suggested the potential for regulatory action. Conclusions This study proposed a method by which campaign planners can develop theory-based mass communication strategies to change health behaviors at the population level. This method might contribute to improving the quality of future mass health communication strategies and further research is needed. PMID:27441626

Ethylene Decomposition Initiated by Ultraviolet Radiation from Low Pressure Mercury Lamps: Kinetics Model Prediction and Experimental Verification.

NASA Astrophysics Data System (ADS)

Jozwiak, Zbigniew Boguslaw

1995-01-01

Ethylene is an important auto-catalytic plant growth hormone. Removal of ethylene from the atmosphere surrounding ethylene-sensitive horticultural products may be very beneficial, allowing an extended period of storage and preventing or delaying the induction of disorders. Various ethylene removal techniques have been studied and put into practice. One technique is based on using low pressure mercury ultraviolet lamps as a source of photochemical energy to initiate chemical reactions that destroy ethylene. Although previous research showed that ethylene disappeared in experiments with mercury ultraviolet lamps, the reactions were not described and the actual cause of ethylene disappearance remained unknown. Proposed causes for this disappearance were the direct action of ultraviolet rays on ethylene, reaction of ethylene with ozone (which is formed when air or gas containing molecular oxygen is exposed to radiation emitted by this type of lamp), or reactions with atomic oxygen leading to formation of ozone. The objective of the present study was to determine the set of physical and chemical actions leading to the disappearance of ethylene from artificial storage atmosphere under conditions of ultraviolet irradiation. The goal was achieved by developing a static chemical model based on the physical properties of a commercially available ultraviolet lamp, the photochemistry of gases, and the kinetics of chemical reactions. The model was used to perform computer simulations predicting time dependent concentrations of chemical species included in the model. Development of the model was accompanied by the design of a reaction chamber used for experimental verification. The model provided a good prediction of the general behavior of the species involved in the chemistry under consideration; however the model predicted lower than measured rate of ethylene disappearance. Some reasons for the model -experiment disagreement are radiation intensity averaging, the experimental technique, mass transfer in the chamber, and incompleteness of the set of chemical reactions included in the model. The work is concluded with guidelines for development of a more complex mathematical model that includes elements of mass transfer inside the reaction chamber, and uses a three dimensional approach to distribute radiation from the low pressure mercury ultraviolet tube.

Ferromagnetic mass fixed on a spring and subjected to an electromagnet powered by self-sustained oscillators

NASA Astrophysics Data System (ADS)

Abobda, L. T.; Woafo, P.

2014-12-01

The study of a ferromagnetic mass, fixed on a spring and subjected to an electromagnet powered by a Van der Pol (VDP) oscillator and by a Hindmarsh-Rose (HR) oscillator is performed, to serve as an electromechanical devices, but also to mimic the action of a natural pacemaker and nerves on a cardiac assist device or artificial heart. The excitation with the VDP oscillator shows in the mechanical part the transition from harmonic, periodic, biperiodic up to bursting oscillations, high displacement without pull-in instability in the free dynamics regime. Under DC plus square wave excitation, there is a coexistence of the bursting oscillations of the free dynamics and the one of the modulated dynamics. Considering the action of a HR oscillator, it is found transition from spikes, bursting oscillations, relaxation spikes, multiperiodic and sinusoidal oscillations under DC or DC plus square wave excitation. These electrical behaviors are transferred to the mechanical part which can then adopt spiking or bursting dynamics as the HR oscillator. For this electromechanical model, the VDP oscillator is more efficient than the HR oscillator to induce pulsatile pumping function with higher amplitude and to react to external influences without pull-in.

Time to act: crossing borders in global AIDS prevention.

PubMed

Convisser, J; Thuermer, K

1993-01-01

After 9 months of market research and collaboration among local health officials, businesses, politicians, and teenagers, Population Services International (PSI) launched Project ACTION in Portland, Oregon on December 1, 1992. It is the first PSI project in the United States concerned with prevention of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) in American youth. PSI has conducted 23 projects worldwide over the last 20 years that were based on social marketing (the utilization of commercial marketing techniques to promote healthy behavior). The objective of the project is promotion of safe sex practices, especially the use of condoms, among sexually active youth, aged 12-21. The Mass Media and Condom Social Marketing project of PSI in Zaire was used as a model for Project ACTION. Techniques used include mass marketing campaigns, point of purchase promotion, improvement of access to key products among target populations, and adjustment of purchase price to create a market. The target populations include adolescents who use drugs, are involved with the juvenile justice system, are pregnant, have a problem home environment, are homeless or live on the street, are chronically absent from school, or have a history of sexually transmitted disease.

Free-Spinning Tunnel Tests of a 1/24-Scale Model of the Grumman XTB3F-1 Airplane, TED No. NACA DE304

NASA Technical Reports Server (NTRS)

Berman, Theodore

1947-01-01

In accordance with a request of the Bureau of Aeronautics, Navy Department, tests were performed in the Langley 20-foot free-spinning tunnel to determine the spin and recovery characteristics of a 1/24 scale model of the Grumman XTB3F-1 airplane. The airplane is a two-place, midwing torpedo bomber equipped with a tractor propeller and an auxiliary jet engine. The effect of control setting and movement on the erect and inverted spin and recovery characteristics of the model were determined for the normal loading. Brief tests with mass extended slightly along the fuselage were also made, however, in order to determine the effect of such a mass variation on elevator effectiveness. Tests were performed to determine the size of emergency spin-recovery tail and wing-tip parachutes required for satisfactory recovery by parachute action alone. The investigation also included emergency pilot-escape tests and tests to determine the rudder pedal and elevator stick forces necessary to move the rudder and elevator for recovery.

The framed Standard Model (II) — A first test against experiment

NASA Astrophysics Data System (ADS)

Chan, Hong-Mo; Tsou, Sheung Tsun

2015-10-01

Apart from the qualitative features described in Paper I (Ref. 1), the renormalization group equation derived for the rotation of the fermion mass matrices are amenable to quantitative study. The equation depends on a coupling and a fudge factor and, on integration, on 3 integration constants. Its application to data analysis, however, requires the input from experiment of the heaviest generation masses mt, mb, mτ, mν3 all of which are known, except for mν3. Together then with the theta-angle in the QCD action, there are in all 7 real unknown parameters. Determining these 7 parameters by fitting to the experimental values of the masses mc, mμ, me, the CKM elements |Vus|, |Vub|, and the neutrino oscillation angle sin2θ 13, one can then calculate and compare with experiment the following 12 other quantities ms, mu/md, |Vud|, |Vcs|, |Vtb|, |Vcd|, |Vcb|, |Vts|, |Vtd|, J, sin22θ 12, sin22θ 23, and the results all agree reasonably well with data, often to within the stringent experimental error now achieved. Counting the predictions not yet measured by experiment, this means that 17 independent parameters of the standard model are now replaced by 7 in the FSM.

The impact of mass media health communication on health decision-making and medical advice-seeking behavior of u.s. Hispanic population.

PubMed

De Jesus, Maria

2013-01-01

Mass media health communication has enormous potential to drastically alter how health-related information is disseminated and obtained by different populations. However, there is little evidence regarding the influence of media channels on health decision-making and medical advice-seeking behaviors among the Hispanic population. The Pew 2007 Hispanic Healthcare Survey was used to test the hypothesis that the amount of mass media health communication (i.e., quantity of media-based health information received) is more likely to influence Hispanic adults' health decision-making and medical advice-seeking behavior compared to health literacy and language proficiency variables. Results indicated that quantity of media-based health information is positively associated with health decision-making and medical advice-seeking behavior above and beyond the influence of health literacy and English and Spanish language proficiency. In a context where physician-patient dynamics are increasingly shifting from a passive patient role model to a more active patient role model, media-based health information can serve as an influential cue to action, prompting Hispanic individuals to make certain health-related decisions and to seek more health advice and information from a health provider. Study implications are discussed.

`Skinny Milky Way please', says Sagittarius

NASA Astrophysics Data System (ADS)

Gibbons, S. L. J.; Belokurov, V.; Evans, N. W.

2014-12-01

Motivated by recent observations of the Sagittarius stream, we devise a rapid algorithm to generate faithful representations of the centroids of stellar tidal streams formed in a disruption of a progenitor of an arbitrary mass in an arbitrary potential. Our method works by releasing swarms of test particles at the Lagrange points around the satellite and subsequently evolving them in a combined potential of the host and the progenitor. We stress that the action of the progenitor's gravity is crucial to making streams that look almost indistinguishable from the N-body realizations, as indeed ours do. The method is tested on mock stream data in three different Milky Way potentials with increasing complexity, and is shown to deliver unbiased inference on the Galactic mass distribution out to large radii. When applied to the observations of the Sagittarius stream, our model gives a natural explanation of the stream's apocentric distances and the differential orbital precession. We, therefore, provide a new independent measurement of the Galactic mass distribution beyond 50 kpc. The Sagittarius stream model favours a light Milky Way with the mass 4.1 ± 0.4 × 1011 M⊙ at 100 kpc, which can be extrapolated to 5.6 ± 1.2 × 1011 M⊙ at 200 kpc. Such a low mass for the Milky Way Galaxy is in good agreement with estimates from the kinematics of halo stars and from the satellite galaxies (once Leo I is removed from the sample). It entirely removes the `Too Big To Fail Problem'.

Terminalia catappa L.: a medicinal plant from the Caribbean pharmacopeia with anti-Helicobacter pylori and antiulcer action in experimental rodent models.

PubMed

Pinheiro Silva, Laísa; Damacena de Angelis, Célio; Bonamin, Flavia; Kushima, Hélio; José Mininel, Francisco; Campaner Dos Santos, Lourdes; Karina Delella, Flavia; Luis Felisbino, Sergio; Vilegas, Wagner; Regina Machado da Rocha, Lucia; Aparecido Dos Santos Ramos, Matheus; Maria Bauab, Tais; Toma, Walber; Akiko Hiruma-Lima, Clelia

2015-01-15

Terminalia catappa L. (Combretaceae) is a medicinal plant listed as a pharmacopeia vegetable from Caribbean to treat gastritis. The objective of this study was to evaluate the gastroprotective and healing effect of the aqueous fraction (FrAq) obtained from the leaves of Terminalia catappa and to determine the antiulcer mechanism of action in experimental rodent models and its activity to Helicobacter pylori. In rodents, the FrAq was challenged by different necrotizing agents, such as absolute ethanol and ischemia-reperfusion injury. The antiulcer mechanism of action of FrAq was assessed and the healing effects of the fraction after seven and 14 days of treatment was evaluated by matrix metalloproteinase activity (MMP-2 and MMP-9). The toxicological effect of subacute treatment with FrAq during 14 days of treatment was also analyzed. The anti-Helicobacter pylori activity was determined by microdilution. The phytochemical study of the fraction was analyzed by experiments with FIA-ESI-IT-MS(n) (Direct Flow Analysis-ionization Electrospray Ion Trap Tandem Mass Spectrometry) and high performance liquid chromatography (HPLC) coupled to a photodiode array (PDA). Oral treatment with FrAq (25mg/kg) significantly decreased the number of ulcerative lesions induced by ethanol and ischemia/reperfusion injury. The action of FrAq was mediated by the activation of defensive mucosa-protective factors, such as increases in mucus production, the nitric oxide (NO) pathway and endogenous prostaglandins. Oral treatment with FrAq for seven and 14 days significantly reduced the lesion area (80% and 37%, respectively) compared to the negative control group. Analyses of MMP-9 and MMP-2 activity from gastric mucosa confirmed the accelerated gastric healing effect of FrAq. This extract also presented considerable activity against Helicobacter pylori. The mass spectrum and MS/MS of the aqueous fraction indicates the existence of many different phenolic compounds, including punicalagin, punicalin, and gallagic acid, among others. We concluded that FrAq from Terminalia catappa leaves has excellent preventive and curative effects on acute and chronic induced gastric ulcers and showed an important profile against Helicobacter pylori. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Strategies for Improved Hospital Response to Mass Casualty Incidents.

PubMed

TariVerdi, Mersedeh; Miller-Hooks, Elise; Kirsch, Thomas

2018-03-19

Mass casualty incidents are a concern in many urban areas. A community's ability to cope with such events depends on the capacities and capabilities of its hospitals for handling a sudden surge in demand of patients with resource-intensive and specialized medical needs. This paper uses a whole-hospital simulation model to replicate medical staff, resources, and space for the purpose of investigating hospital responsiveness to mass casualty incidents. It provides details of probable demand patterns of different mass casualty incident types in terms of patient categories and arrival patterns, and accounts for related transient system behavior over the response period. Using the layout of a typical urban hospital, it investigates a hospital's capacity and capability to handle mass casualty incidents of various sizes with various characteristics, and assesses the effectiveness of designed demand management and capacity-expansion strategies. Average performance improvements gained through capacity-expansion strategies are quantified and best response actions are identified. Capacity-expansion strategies were found to have superadditive benefits when combined. In fact, an acceptable service level could be achieved by implementing only 2 to 3 of the 9 studied enhancement strategies. (Disaster Med Public Health Preparedness. 2018;page 1 of 13).

Mass Deacidification Systems: Planning and Managerial Decision Making.

ERIC Educational Resources Information Center

Turko, Karen

Library administrators, faced with the problems of acid-paper deterioration, are examining mass deacidification procedures. Mass deacidification of acidic books while they are still physically sound and not yet brittle is the most cost-effective corrective action to extend the life of the paper. There are currently at least five mass…

The Center of Mass of a Soft Spring

ERIC Educational Resources Information Center

Serna, Juan D.; Joshi, Amitabh

2011-01-01

This article uses calculus to find the center of mass of a soft, vertically suspended, cylindrical helical spring, which necessarily is stretched non-uniformly by the action of gravity. A general expression for the vertical position of the center of mass is obtained and compared with other results in the literature.

Charmed Hadron Spectrum and Interactions

NASA Astrophysics Data System (ADS)

Liu, Liuming

Studying hadrons containing heavy quarks in lattice QCD is challenging mainly due to finite lattice spacing effects. To control the discretization errors, mQa is required to be much less than 1, where mQ is the quark mass and a is the lattice spacing. For currently accessible lattice spacings, the charm quark mass doesn't satisfy this requirement. One approach to simulate heavy quarks on the lattice is non-relativestic QCD, which treats heavy quark as a static source and expand the lattice quark action in powers of 1mQa . Unfortunately, the charm quark is not heavy enough to justify this expansion. An other is Heavy Quark Effective Theory (HQET) matched on QCD. Non-relativestic QCD and HQET are mainly used for bottom quark. Relativistic heavy-quark action, which incorporates both small mass and large mass formulations, is better suited to study the charm quark sector. The discretization errors can be reduced systematically following Symanzik improvement. In this work, we use the relativistic heavy quark action to study the charmed hadron spectrum and interactions in full lattice QCD. For the light quarks we use domain-wall fermions in the valence sector and improved Kogut-Susskind sea quarks. The parameters in the heavy quark action are tuned to reduce lattice artifacts and match the charm quark mass and the action is tested by calculating the low-lying charmonium spectrum. We compute the masses of the spin-1/2 singly and doubly charmed baryons. For the singly charmed baryons, our results are in good agreement with experiment within our systematics. For the doubly charmed baryon xicc we find the isospin-averaged mass to be MXcc = 3665 +/- 17 +/- 14+0-78 MeV; the three given uncertainties are statistical, systematic and an estimate of lattice discretization errors, respectively. In addition, we predict the mass splitting of the (isospin-averaged) spin-1/2 O cc with the xicc to be MWcc-MXcc = 98 +/- 9 +/- 22 +/- 13 MeV (in this mass splitting, the leading discretization errors are also suppressed by SU(3) symmetry). Combining this splitting with our determination of MXcc leads to our prediction of the spin-1/2 Occ mass, MWcc = 3763 +/- 19 +/- 26+13-79 MeV. We calculate the scattering lengths of the charmed mesons with the light pseudoscalar mesons. The calculation is performed for four different light quark masses and extrapolated to the physical point using chiral perturbation formulas to next-to-next-to-leading order. The low energy constants are determined and used to make predictions. We find relatively strong attractive interaction in DK channels, which is closely related to the structure of DsJ(2317) state. The scattering of charmonium with light hadrons is also studied. Particularly, we find very weak attractive interaction between J/Psi and nucleon, in this channel the dominate interaction is attractive gluonic van der Walls and it could lead to molecular-like bound states.

Fluctuations and correlations of conserved charges in QCD at finite temperature with effective models

NASA Astrophysics Data System (ADS)

Fu, Wei-Jie; Liu, Yu-Xin; Wu, Yue-Liang

2010-01-01

We study fluctuations of conserved charges including baryon number, electric charge, and strangeness as well as the correlations among these conserved charges in the 2+1 flavor Polyakov-Nambu-Jona-Lasinio model at finite temperature. The calculated results are compared with those obtained from recent lattice calculations performed with an improved staggered fermion action at two values of the lattice cutoff with almost physical up and down quark masses and a physical value for the strange quark mass. We find that our calculated results are well consistent with those obtained in lattice calculations except for some quantitative differences for fluctuations related with strange quarks. Our calculations indicate that there is a pronounced cusp in the ratio of the quartic to quadratic fluctuations of baryon number, i.e. χ4B/χ2B, at the critical temperature during the phase transition, which confirms that χ4B/χ2B is a useful probe of the deconfinement and chiral phase transition.

Sex Steroid Actions in Male Bone

PubMed Central

Laurent, Michaël R.; Claessens, Frank; Gielen, Evelien; Lagerquist, Marie K.; Vandenput, Liesbeth; Börjesson, Anna E.; Ohlsson, Claes

2014-01-01

Sex steroids are chief regulators of gender differences in the skeleton, and male gender is one of the strongest protective factors against osteoporotic fractures. This advantage in bone strength relies mainly on greater cortical bone expansion during pubertal peak bone mass acquisition and superior skeletal maintenance during aging. During both these phases, estrogens acting via estrogen receptor-α in osteoblast lineage cells are crucial for male cortical and trabecular bone, as evident from conditional genetic mouse models, epidemiological studies, rare genetic conditions, genome-wide meta-analyses, and recent interventional trials. Genetic mouse models have also demonstrated a direct role for androgens independent of aromatization on trabecular bone via the androgen receptor in osteoblasts and osteocytes, although the target cell for their key effects on periosteal bone formation remains elusive. Low serum estradiol predicts incident fractures, but the highest risk occurs in men with additionally low T and high SHBG. Still, the possible clinical utility of serum sex steroids for fracture prediction is unknown. It is likely that sex steroid actions on male bone metabolism rely also on extraskeletal mechanisms and cross talk with other signaling pathways. We propose that estrogens influence fracture risk in aging men via direct effects on bone, whereas androgens exert an additional antifracture effect mainly via extraskeletal parameters such as muscle mass and propensity to fall. Given the demographic trends of increased longevity and consequent rise of osteoporosis, an increased understanding of how sex steroids influence male bone health remains a high research priority. PMID:25202834

Mass-action model analysis of the apparent molar volume and heat capacity of pluronics in water and liposome suspensions at 25 °C.

PubMed

Quirion, François; Meilleur, Luc; Lévesque, Isabelle

2013-07-09

Pluronics are block copolymers composed of a central block of polypropylene oxide and two side chains of polyethylene oxide. They are used in water to generate aggregates and gels or added to phospholipid suspensions to prepare microparticles for drug delivery applications. The structure of these systems has been widely investigated. However, little is known about the mechanisms leading to these structures. This investigation compares the apparent molar volumes and heat capacities of Pluronics F38, F108, F127, P85, P104, and P103 at 25 °C in water and in the presence of lecithin liposomes. The changes in molar volumes, heat capacities, and enthalpies generated by a mass-action model are in good agreement with the loss of hydrophobic hydration of the polypropylene oxide central block of the Pluronics. However, the molecularity of the endothermic transitions is much smaller than the aggregation numbers reported in the literature for the same systems. It is suggested that Pluronics go through dehydration of their central block to form unimolecular or small entities having a hydrophobic polypropylene oxide core. In water, these entities would assemble athermally to form larger aggregates. In the presence of liposomes, they would be transferred into the hydrophobic lecithin bilayers of the liposomes. Light transmission experiments suggest that the liposome suspensions are significantly altered only when the added Pluronics are in the dehydrated state.

Non-disruptive tactics of suppression are superior in countering terrorism, insurgency, and financial panics.

PubMed

Siegel, David A

2011-04-13

Suppressing damaging aggregate behaviors such as insurgency, terrorism, and financial panics are important tasks of the state. Each outcome of these aggregate behaviors is an emergent property of a system in which each individual's action depends on a subset of others' actions, given by each individual's network of interactions. Yet there are few explicit comparisons of strategies for suppression, and none that fully incorporate the interdependence of individual behavior. Here I show that suppression tactics that do not require the removal of individuals from networks of interactions are nearly always more effective than those that do. I find using simulation analysis of a general model of interdependent behavior that the degree to which such less disruptive suppression tactics are superior to more disruptive ones increases in the propensity of individuals to engage in the behavior in question. Thus, hearts-and-minds approaches are generally more effective than force in counterterrorism and counterinsurgency, and partial insurance is usually a better tactic than gag rules in quelling financial panics. Differences between suppression tactics are greater when individual incentives to support terrorist or insurgent groups, or susceptibilities to financial panic, are higher. These conclusions have utility for policy-makers seeking to end bloody conflicts and prevent financial panics. As the model also applies to mass protest, its conclusions provide insight as well into the likely effects of different suppression strategies undertaken by authoritarian regimes seeking to hold on to power in the face of mass movements seeking to end them.

Chasing the observational signatures of seed black holes at z > 7: candidate statistics

NASA Astrophysics Data System (ADS)

Valiante, Rosa; Schneider, Raffaella; Graziani, Luca; Zappacosta, Luca

2018-03-01

Supermassive black holes (SMBHs) of 109-1010 M⊙ were already in place ˜13 Gyr ago, at z > 6. Super-Eddington growth of low-mass BH seeds (˜100 M⊙) or less extreme accretion on to˜105 M⊙ seeds have been recently considered as the main viable routes to these SMBHs. Here, we study the statistics of these SMBH progenitors at z ˜ 6. The growth of low- and high-mass seeds and their host galaxies are consistently followed using the cosmological data constrained model GAMETE/QSODUST, which reproduces the observed properties of high-z quasars, like SDSS J1148+5251. We show that both seed formation channels can be in action over a similar redshift range 15 < z < 18 and are found in dark matter haloes with comparable mass, ˜5 × 107 M⊙. However, as long as the systems evolve in isolation (i.e. no mergers occur), noticeable differences in their properties emerge: At z ≥ 10 galaxies hosting high-mass seeds have smaller stellar mass and metallicity, the BHs accrete gas at higher rates and star formation proceeds less efficiently than in low-mass seeds hosts. At z < 10 these differences are progressively erased, as the systems experience minor or major mergers and every trace of the BH origin gets lost.

Experimentally fitted biodynamic models for pedestrian-structure interaction in walking situations

NASA Astrophysics Data System (ADS)

Toso, Marcelo André; Gomes, Herbert Martins; da Silva, Felipe Tavares; Pimentel, Roberto Leal

2016-05-01

The interaction between moving humans and structures usually occurs in slender structures in which the level of vibration is potentially high. Furthermore, there is the addition of mass to the structural system due to the presence of people and an increase in damping due to the human body´s ability to absorb vibrational energy. In this paper, a test campaign is presented to obtain parameters for a single degree of freedom (SDOF) biodynamic model that represents the action of a walking pedestrian in the vertical direction. The parameters of this model are the mass (m), damping (c) and stiffness (k). The measurements were performed on a force platform, and the inputs were the spectral acceleration amplitudes of the first three harmonics at the waist level of the test subjects and the corresponding amplitudes of the first three harmonics of the vertical ground reaction force. This leads to a system of nonlinear equations that is solved using a gradient-based optimization algorithm. A set of individuals took part in the tests to ensure inter-subject variability, and, regression expressions and an artificial neural network (ANN) were used to relate the biodynamic parameters to the pacing rate and the body mass of the pedestrians. The results showed some scatter in damping and stiffness that could not be precisely correlated with the masses and pacing rates of the subjects. The use of the ANN resulted in significant improvements in the parameter expressions with a low uncertainty. Finally, the measured vertical accelerations on a prototype footbridge show the adequacy of the numerical model for the representation of the effects of walking pedestrians on a structure. The results are consistent for many crowd densities.

Overmassive black holes in the MBH-σ diagram do not belong to over (dry) merged galaxies

NASA Astrophysics Data System (ADS)

Savorgnan, Giulia A. D.; Graham, Alister W.

2015-01-01

Semi-analytical models in a Λ cold dark matter cosmology have predicted the presence of outlying, `overmassive' black holes at the high-mass end of the (black hole mass-galaxy velocity dispersion) MBH-σ diagram (which we update here with a sample of 89 galaxies). They are a consequence of having experienced more dry mergers - thought not to increase a galaxy's velocity dispersion - than the `main-sequence' population. Wet mergers and gas-rich processes, on the other hand, preserve the main correlation. Due to the scouring action of binary supermassive black holes, the extent of these dry mergers (since the last significant wet merger) can be traced by the ratio between the central stellar mass deficit and the black hole mass (Mdef,*/MBH). However, in a sample of 23 galaxies with partially depleted cores, including central cluster galaxies, we show that the `overmassive' black holes are actually hosted by galaxies that appear to have undergone the lowest degree of such merging. In addition, the rotational kinematics of 37 galaxies in the MBH-σ diagram reveals that fast and slow rotators are not significantly offset from each other, also contrary to what is expected if these two populations were the product of wet and dry mergers, respectively. The observations are thus not in accordance with model predictions and further investigation is required.

Wave‐induced Hydraulic Forces on Submerged Aquatic Plants in Shallow Lakes

PubMed Central

SCHUTTEN, J.; DAINTY, J.; DAVY, A. J.

2004-01-01

• Background and Aims Hydraulic pulling forces arising from wave action are likely to limit the presence of freshwater macrophytes in shallow lakes, particularly those with soft sediments. The aim of this study was to develop and test experimentally simple models, based on linear wave theory for deep water, to predict such forces on individual shoots. • Methods Models were derived theoretically from the action of the vertical component of the orbital velocity of the waves on shoot size. Alternative shoot‐size descriptors (plan‐form area or dry mass) and alternative distributions of the shoot material along its length (cylinder or inverted cone) were examined. Models were tested experimentally in a flume that generated sinusoidal waves which lasted 1 s and were up to 0·2 m high. Hydraulic pulling forces were measured on plastic replicas of Elodea sp. and on six species of real plants with varying morphology (Ceratophyllum demersum, Chara intermedia, Elodea canadensis, Myriophyllum spicatum, Potamogeton natans and Potamogeton obtusifolius). • Key Results Measurements on the plastic replicas confirmed predicted relationships between force and wave phase, wave height and plant submergence depth. Predicted and measured forces were linearly related over all combinations of wave height and submergence depth. Measured forces on real plants were linearly related to theoretically derived predictors of the hydraulic forces (integrals of the products of the vertical orbital velocity raised to the power 1·5 and shoot size). • Conclusions The general applicability of the simplified wave equations used was confirmed. Overall, dry mass and plan‐form area performed similarly well as shoot‐size descriptors, as did the conical or cylindrical models of shoot distribution. The utility of the modelling approach in predicting hydraulic pulling forces from relatively simple plant and environmental measurements was validated over a wide range of forces, plant sizes and species. PMID:14988098

Testing the gravitational instability hypothesis?

NASA Technical Reports Server (NTRS)

Babul, Arif; Weinberg, David H.; Dekel, Avishai; Ostriker, Jeremiah P.

1994-01-01

We challenge a widely accepted assumption of observational cosmology: that successful reconstruction of observed galaxy density fields from measured galaxy velocity fields (or vice versa), using the methods of gravitational instability theory, implies that the observed large-scale structures and large-scale flows were produced by the action of gravity. This assumption is false, in that there exist nongravitational theories that pass the reconstruction tests and gravitational theories with certain forms of biased galaxy formation that fail them. Gravitational instability theory predicts specific correlations between large-scale velocity and mass density fields, but the same correlations arise in any model where (a) structures in the galaxy distribution grow from homogeneous initial conditions in a way that satisfies the continuity equation, and (b) the present-day velocity field is irrotational and proportional to the time-averaged velocity field. We demonstrate these assertions using analytical arguments and N-body simulations. If large-scale structure is formed by gravitational instability, then the ratio of the galaxy density contrast to the divergence of the velocity field yields an estimate of the density parameter Omega (or, more generally, an estimate of beta identically equal to Omega(exp 0.6)/b, where b is an assumed constant of proportionality between galaxy and mass density fluctuations. In nongravitational scenarios, the values of Omega or beta estimated in this way may fail to represent the true cosmological values. However, even if nongravitational forces initiate and shape the growth of structure, gravitationally induced accelerations can dominate the velocity field at late times, long after the action of any nongravitational impulses. The estimated beta approaches the true value in such cases, and in our numerical simulations the estimated beta values are reasonably accurate for both gravitational and nongravitational models. Reconstruction tests that show correlations between galaxy density and velocity fields can rule out some physically interesting models of large-scale structure. In particular, successful reconstructions constrain the nature of any bias between the galaxy and mass distributions, since processes that modulate the efficiency of galaxy formation on large scales in a way that violates the continuity equation also produce a mismatch between the observed galaxy density and the density inferred from the peculiar velocity field. We obtain successful reconstructions for a gravitational model with peaks biasing, but we also show examples of gravitational and nongravitational models that fail reconstruction tests because of more complicated modulations of galaxy formation.

The mass-action law based algorithm for cost-effective approach for cancer drug discovery and development.

PubMed

Chou, Ting-Chao

2011-01-01

The mass-action law based system analysis via mathematical induction and deduction lead to the generalized theory and algorithm that allows computerized simulation of dose-effect dynamics with small size experiments using a small number of data points in vitro, in animals, and in humans. The median-effect equation of the mass-action law deduced from over 300 mechanism specific-equations has been shown to be the unified theory that serves as the common-link for complicated biomedical systems. After using the median-effect principle as the common denominator, its applications are mechanism-independent, drug unit-independent, and dynamic order-independent; and can be used generally for single drug analysis or for multiple drug combinations in constant-ratio or non-constant ratios. Since the "median" is the common link and universal reference point in biological systems, these general enabling lead to computerized quantitative bio-informatics for econo-green bio-research in broad disciplines. Specific applications of the theory, especially relevant to drug discovery, drug combination, and clinical trials, have been cited or illustrated in terms of algorithms, experimental design and computerized simulation for data analysis. Lessons learned from cancer research during the past fifty years provide a valuable opportunity to reflect, and to improve the conventional divergent approach and to introduce a new convergent avenue, based on the mass-action law principle, for the efficient cancer drug discovery and the low-cost drug development.

The mass-action law based algorithm for cost-effective approach for cancer drug discovery and development

PubMed Central

Chou, Ting-Chao

2011-01-01

The mass-action law based system analysis via mathematical induction and deduction lead to the generalized theory and algorithm that allows computerized simulation of dose-effect dynamics with small size experiments using a small number of data points in vitro, in animals, and in humans. The median-effect equation of the mass-action law deduced from over 300 mechanism specific-equations has been shown to be the unified theory that serves as the common-link for complicated biomedical systems. After using the median-effect principle as the common denominator, its applications are mechanism-independent, drug unit-independent, and dynamic order-independent; and can be used generally for single drug analysis or for multiple drug combinations in constant-ratio or non-constant ratios. Since the “median” is the common link and universal reference point in biological systems, these general enabling lead to computerized quantitative bio-informatics for econo-green bio-research in broad disciplines. Specific applications of the theory, especially relevant to drug discovery, drug combination, and clinical trials, have been cited or illustrated in terms of algorithms, experimental design and computerized simulation for data analysis. Lessons learned from cancer research during the past fifty years provide a valuable opportunity to reflect, and to improve the conventional divergent approach and to introduce a new convergent avenue, based on the mass-action law principle, for the efficient cancer drug discovery and the low-cost drug development. PMID:22016837

Fluctuations and correlations of net baryon number, electric charge, and strangeness: A comparison of lattice QCD results with the hadron resonance gas model

NASA Astrophysics Data System (ADS)

Bazavov, A.; Bhattacharya, Tanmoy; DeTar, C. E.; Ding, H.-T.; Gottlieb, Steven; Gupta, Rajan; Hegde, P.; Heller, Urs M.; Karsch, F.; Laermann, E.; Levkova, L.; Mukherjee, Swagato; Petreczky, P.; Schmidt, Christian; Soltz, R. A.; Soeldner, W.; Sugar, R.; Vranas, Pavlos M.

2012-08-01

We calculate the quadratic fluctuations of net baryon number, electric charge and strangeness as well as correlations among these conserved charges in (2+1)-flavor lattice QCD at zero chemical potential. Results are obtained using calculations with tree-level improved gauge and the highly improved staggered quark actions with almost physical light and strange quark masses at three different values of the lattice cutoff. Our choice of parameters corresponds to a value of 160 MeV for the lightest pseudoscalar Goldstone mass and a physical value of the kaon mass. The three diagonal charge susceptibilities and the correlations among conserved charges have been extrapolated to the continuum limit in the temperature interval 150MeV≤T≤250MeV. We compare our results with the hadron resonance gas (HRG) model calculations and find agreement with HRG model results only for temperatures T≲150MeV. We observe significant deviations in the temperature range 160MeV≲T≲170MeV and qualitative differences in the behavior of the three conserved charge sectors. At T≃160MeV quadratic net baryon number fluctuations in QCD agree with HRG model calculations, while the net electric charge fluctuations in QCD are about 10% smaller and net strangeness fluctuations are about 20% larger. These findings are relevant to the discussion of freeze-out conditions in relativistic heavy ion collisions.

Black holes as bubble nucleation sites

NASA Astrophysics Data System (ADS)

Gregory, Ruth; Moss, Ian G.; Withers, Benjamin

2014-03-01

We consider the effect of inhomogeneities on the rate of false vacuum decay. Modelling the inhomogeneity by a black hole, we construct explicit Euclidean instantons which describe the nucleation of a bubble of true vacuum centred on the inhomogeneity. We find that inhomogeneity significantly enhances the nucleation rate over that of the Coleman-de Luccia instanton — the black hole acts as a nucleation site for the bubble. The effect is larger than previously believed due to the contributions to the action from conical singularities. For a sufficiently low initial mass, the original black hole is replaced by flat space during this process, as viewed by a single causal patch observer. Increasing the initial mass, we find a critical value above which a black hole remnant survives the process. This resulting black hole can have a higher mass than the original black hole, but always has a lower entropy. We compare the process to bubble-to-bubble transitions, where there is a semi-classical Lorentzian description in the WKB approximation.

Dynamic Diversity: Toward a Contextual Understanding of Critical Mass

ERIC Educational Resources Information Center

Garces, Liliana M.; Jayakumar, Uma M.

2014-01-01

Through an analysis of relevant social science evidence, this article provides a deeper understanding of critical mass, a concept that has become central in litigation efforts related to affirmative action admissions policies that seek to further the educational benefits of diversity. We demonstrate that the concept of critical mass requires an…

Interaction of a Gas Flow Carrying Nonspherical Microparticles with a Cross Cylinder

NASA Astrophysics Data System (ADS)

Amelyushkin, I. A.; Stasenko, A. L.

2018-05-01

A model of the dynamics of the particles-spheroids carried by a gas flow over a cross cylindrical body and rebounding from it has been developed. In this model, the gas flow around the particles is assumed to be viscous, and the reverse action of the particles on the gas and the collisions between them are not taken into account. The coefficients of recovery of the velocity components of the particles rebounded from the cylinder were determined on the basis of the heuristic theory in which the physical and mechanical properties of colliding bodies are considered. The influence of the ratio between the axes of particles-spheroids on the coefficient of wetting of the cylinder by them, the distributions of the mass-flow density of the particles and their velocity components over the cylinder surface, and the spatial distribution of the indicated quantities of the rotating particles rebounded from the cylinder was investigated numerically. The model proposed can be used for estimating the action of ice microcrystals and particles of volcanic ash emissions and dust storms on the structural elements of aircraft engines and small-size flying vehicles.

Constraining models of f(R) gravity with Planck and WiggleZ power spectrum data

NASA Astrophysics Data System (ADS)

Dossett, Jason; Hu, Bin; Parkinson, David

2014-03-01

In order to explain cosmic acceleration without invoking ``dark'' physics, we consider f(R) modified gravity models, which replace the standard Einstein-Hilbert action in General Relativity with a higher derivative theory. We use data from the WiggleZ Dark Energy survey to probe the formation of structure on large scales which can place tight constraints on these models. We combine the large-scale structure data with measurements of the cosmic microwave background from the Planck surveyor. After parameterizing the modification of the action using the Compton wavelength parameter B0, we constrain this parameter using ISiTGR, assuming an initial non-informative log prior probability distribution of this cross-over scale. We find that the addition of the WiggleZ power spectrum provides the tightest constraints to date on B0 by an order of magnitude, giving log10(B0) < -4.07 at 95% confidence limit. Finally, we test whether the effect of adding the lensing amplitude ALens and the sum of the neutrino mass ∑mν is able to reconcile current tensions present in these parameters, but find f(R) gravity an inadequate explanation.

Interaction of a Gas Flow Carrying Nonspherical Microparticles with a Cross Cylinder

NASA Astrophysics Data System (ADS)

Amelyushkin, I. A.; Stasenko, A. L.

2018-03-01

A model of the dynamics of the particles-spheroids carried by a gas flow over a cross cylindrical body and rebounding from it has been developed. In this model, the gas flow around the particles is assumed to be viscous, and the reverse action of the particles on the gas and the collisions between them are not taken into account. The coefficients of recovery of the velocity components of the particles rebounded from the cylinder were determined on the basis of the heuristic theory in which the physical and mechanical properties of colliding bodies are considered. The influence of the ratio between the axes of particles-spheroids on the coefficient of wetting of the cylinder by them, the distributions of the mass-flow density of the particles and their velocity components over the cylinder surface, and the spatial distribution of the indicated quantities of the rotating particles rebounded from the cylinder was investigated numerically. The model proposed can be used for estimating the action of ice microcrystals and particles of volcanic ash emissions and dust storms on the structural elements of aircraft engines and small-size flying vehicles.

Predicting the Magnetic Properties of ICMEs: A Pragmatic View

NASA Astrophysics Data System (ADS)

Riley, P.; Linker, J.; Ben-Nun, M.; Torok, T.; Ulrich, R. K.; Russell, C. T.; Lai, H.; de Koning, C. A.; Pizzo, V. J.; Liu, Y.; Hoeksema, J. T.

2017-12-01

The southward component of the interplanetary magnetic field plays a crucial role in being able to successfully predict space weather phenomena. Yet, thus far, it has proven extremely difficult to forecast with any degree of accuracy. In this presentation, we describe an empirically-based modeling framework for estimating Bz values during the passage of interplanetary coronal mass ejections (ICMEs). The model includes: (1) an empirically-based estimate of the magnetic properties of the flux rope in the low corona (including helicity and field strength); (2) an empirically-based estimate of the dynamic properties of the flux rope in the high corona (including direction, speed, and mass); and (3) a physics-based estimate of the evolution of the flux rope during its passage to 1 AU driven by the output from (1) and (2). We compare model output with observations for a selection of events to estimate the accuracy of this approach. Importantly, we pay specific attention to the uncertainties introduced by the components within the framework, separating intrinsic limitations from those that can be improved upon, either by better observations or more sophisticated modeling. Our analysis suggests that current observations/modeling are insufficient for this empirically-based framework to provide reliable and actionable prediction of the magnetic properties of ICMEs. We suggest several paths that may lead to better forecasts.

Ghosts in the self-accelerating brane universe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koyama, Kazuya; Institute of Cosmology and Gravitation, Portsmouth University, Portsmouth, PO1 2EG

2005-12-15

We study the spectrum of gravitational perturbations about a vacuum de Sitter brane with the induced 4D Einstein-Hilbert term, in a 5D Minkowski spacetime (DGP model). We consider solutions that include a self-accelerating universe, where the accelerating expansion of the universe is realized without introducing a cosmological constant on the brane. The mass of the discrete mode for the spin-2 graviton is calculated for various Hr{sub c}, where H is the Hubble parameter and r{sub c} is the crossover scale determined by the ratio between the 5D Newton constant and the 4D Newton constant. We show that, if we introducemore » a positive cosmological constant on the brane (Hr{sub c}>1), the spin-2 graviton has mass in the range 01/2. In a self-accelerating universe Hr{sub c}=1, the spin-2 graviton has mass m{sup 2}=2H{sup 2}, which coincides with the mass of the brane fluctuation mode. Then there arises a mixing between the brane fluctuation mode and the spin-2 graviton. We argue that this mixing presumably gives a ghost in the self-accelerating universe by continuity across Hr{sub c}=1, although a careful calculation of the effective action is required to verify this rigorously.« less

Generalized group field theories and quantum gravity transition amplitudes

NASA Astrophysics Data System (ADS)

Oriti, Daniele

2006-03-01

We construct a generalized formalism for group field theories, in which the domain of the field is extended to include additional proper time variables, as well as their conjugate mass variables. This formalism allows for different types of quantum gravity transition amplitudes in perturbative expansion, and we show how both causal spin foam models and the usual a-causal ones can be derived from it, within a sum over triangulations of all topologies. We also highlight the relation of the so-derived causal transition amplitudes with simplicial gravity actions.

Bone modeling and remodeling: potential as therapeutic targets for the treatment of osteoporosis.

PubMed

Langdahl, Bente; Ferrari, Serge; Dempster, David W

2016-12-01

The adult skeleton is renewed by remodeling throughout life. Bone remodeling is a process where osteoclasts and osteoblasts work sequentially in the same bone remodeling unit. After the attainment of peak bone mass, bone remodeling is balanced and bone mass is stable for one or two decades until age-related bone loss begins. Age-related bone loss is caused by increases in resorptive activity and reduced bone formation. The relative importance of cortical remodeling increases with age as cancellous bone is lost and remodeling activity in both compartments increases. Bone modeling describes the process whereby bones are shaped or reshaped by the independent action of osteoblast and osteoclasts. The activities of osteoblasts and osteoclasts are not necessarily coupled anatomically or temporally. Bone modeling defines skeletal development and growth but continues throughout life. Modeling-based bone formation contributes to the periosteal expansion, just as remodeling-based resorption is responsible for the medullary expansion seen at the long bones with aging. Existing and upcoming treatments affect remodeling as well as modeling. Teriparatide stimulates bone formation, 70% of which is remodeling based and 20-30% is modeling based. The vast majority of modeling represents overflow from remodeling units rather than de novo modeling. Denosumab inhibits bone remodeling but is permissive for modeling at cortex. Odanacatib inhibits bone resorption by inhibiting cathepsin K activity, whereas modeling-based bone formation is stimulated at periosteal surfaces. Inhibition of sclerostin stimulates bone formation and histomorphometric analysis demonstrated that bone formation is predominantly modeling based. The bone-mass response to some osteoporosis treatments in humans certainly suggests that nonremodeling mechanisms contribute to this response and bone modeling may be such a mechanism. To date, this has only been demonstrated for teriparatide, however, it is clear that rediscovering a phenomenon that was first observed more half a century ago will have an important impact on our understanding of how new antifracture treatments work.

OXIDATIVE STRESS AS A POSSIBLE MODE OF ACTION FOR ARSENIC CARCINOGENESIS

EPA Science Inventory

Abstract

Many modes of action for arsenic carcinogenesis have been proposed, but few theories have a substantial mass of supporting data. Three stronger theories of arsenic carcinogenesis are production of chromosomal abnormalities, promotion of carcinogenesis and oxidati...

Continuous Human Action Recognition Using Depth-MHI-HOG and a Spotter Model

PubMed Central

Eum, Hyukmin; Yoon, Changyong; Lee, Heejin; Park, Mignon

2015-01-01

In this paper, we propose a new method for spotting and recognizing continuous human actions using a vision sensor. The method is comprised of depth-MHI-HOG (DMH), action modeling, action spotting, and recognition. First, to effectively separate the foreground from background, we propose a method called DMH. It includes a standard structure for segmenting images and extracting features by using depth information, MHI, and HOG. Second, action modeling is performed to model various actions using extracted features. The modeling of actions is performed by creating sequences of actions through k-means clustering; these sequences constitute HMM input. Third, a method of action spotting is proposed to filter meaningless actions from continuous actions and to identify precise start and end points of actions. By employing the spotter model, the proposed method improves action recognition performance. Finally, the proposed method recognizes actions based on start and end points. We evaluate recognition performance by employing the proposed method to obtain and compare probabilities by applying input sequences in action models and the spotter model. Through various experiments, we demonstrate that the proposed method is efficient for recognizing continuous human actions in real environments. PMID:25742172

Mass Transit: Actions Needed for the BART Airport Extension

DOT National Transportation Integrated Search

1996-05-31

The Bay Area Rapid Transit District (BART) intends to spend over $1.1 billion, including $750 million in federal funds, to extend mass transit service to the San Francisco International Airport. The project is controversial, encountering both widespr...

Temperature dependence of standard model CP violation.

PubMed

Brauner, Tomáš; Taanila, Olli; Tranberg, Anders; Vuorinen, Aleksi

2012-01-27

We analyze the temperature dependence of CP violation effects in the standard model by determining the effective action of its bosonic fields, obtained after integrating out the fermions from the theory and performing a covariant gradient expansion. We find nonvanishing CP violating terms starting at the sixth order of the expansion, albeit only in the C-odd-P-even sector, with coefficients that depend on quark masses, Cabibbo-Kobayashi-Maskawa matrix elements, temperature and the magnitude of the Higgs field. The CP violating effects are observed to decrease rapidly with temperature, which has important implications for the generation of a matter-antimatter asymmetry in the early Universe. Our results suggest that the cold electroweak baryogenesis scenario may be viable within the standard model, provided the electroweak transition temperature is at most of order 1 GeV.

Reducing the Consequences of a Nuclear Detonation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buddemeier, B R

2007-11-09

The 2002 National Strategy to Combat Weapons of Mass Destruction states that 'the United States must be prepared to respond to the use of WMD against our citizens, our military forces, and those of friends and allies'. Scenario No.1 of the 15 Department of Homeland Security national planning scenarios is an improvised nuclear detonation in the national capitol region. An effective response involves managing large-scale incident response, mass casualty, mass evacuation, and mass decontamination issues. Preparedness planning activities based on this scenario provided difficult challenges in time critical decision making and managing a large number of casualties within the hazardmore » area. Perhaps even more challenging is the need to coordinate a large scale response across multiple jurisdictions and effectively responding with limited infrastructure and resources. Federal response planning continues to make improvements in coordination and recommending protective actions, but much work remains. The most critical life-saving activity depends on actions taken in the first few minutes and hours of an event. The most effective way to reduce the enormous national and international social and economic disruptions from a domestic nuclear explosion is through planning and rapid action, from the individual to the federal response. Anticipating response resources for survivors based on predicted types and distributions of injuries needs to be addressed.« less

Minima de L'intégrale D'action du Problème Newtoniende 4 Corps de Masses Égales Dans R3: Orbites `Hip-Hop'

NASA Astrophysics Data System (ADS)

Chenciner, Alain; Venturelli, Andrea

2000-09-01

We consider the problem of 4 bodies of equal masses in R 3 for the Newtonian r-1 potential. We address the question of the absolute minima of the action integral among (anti)symmetric loops of class H 1 whose period is fixed. It is the simplest case for which the results of [4] (corrected in [5]) do not apply: the minima cannot be the relative equilibria whose configuration is an absolute minimum of the potential among the configurations having a given moment of inertia with respect to their center of mass. This is because the regular tetrahedron cannot have a relative equilibrium motion in R 3 (see [2]). We show that the absolute minima of the action are not homographic motions. We also show that if we force the configuration to admit a certain type of symmetry of order 4, the absolute minimum is a collisionless orbit whose configuration ‘hesitates’ between the central configuration of the square and the one of the tetrahedron. We call these orbits ‘hip-hop’. A similar result holds in case of a symmetry of order 3 where the central configuration of the equilateral triangle with a body at the center of mass replaces the square.

Importance of oestrogen receptors to preserve functional β-cell mass in diabetes.

PubMed

Tiano, Joseph P; Mauvais-Jarvis, Franck

2012-02-14

Protecting the functional mass of insulin-producing β cells of the pancreas is a major therapeutic challenge in patients with type 1 (T1DM) or type 2 diabetes mellitus (T2DM). The gonadal hormone 17β-oestradiol (E2) is involved in reproductive, bone, cardiovascular and neuronal physiology. In rodent models of T1DM and T2DM, treatment with E2 protects pancreatic β cells against oxidative stress, amyloid polypeptide toxicity, lipotoxicity and apoptosis. Three oestrogen receptors (ERs)--ERα, ERβ and the G protein-coupled ER (GPER)--have been identified in rodent and human β cells. Whereas activation of ERα enhances glucose-stimulated insulin biosynthesis, reduces islet toxic lipid accumulation and promotes β-cell survival from proapoptotic stimuli, activation of ERβ increases glucose-stimulated insulin secretion. However, activation of GPER protects β cells from apoptosis, raises glucose-stimulated insulin secretion and lipid homeostasis without affecting insulin biosynthesis. Oestrogens are also improving islet engraftment in rodent models of pancreatic islet transplantation. This Review describes developments in the role of ERs in islet insulin biosynthesis and secretion, lipid homeostasis and survival. Moreover, we discuss why and how enhancing ER action in β cells without the undesirable effect of general oestrogen therapy is a therapeutic avenue to preserve functional β-cell mass in patients with diabetes mellitus.

Selective androgen receptor modulators as function promoting therapies.

PubMed

Bhasin, Shalender; Jasuja, Ravi

2009-05-01

The past decade has witnessed an unprecedented discovery effort to develop selective androgen receptor modulators (SARMs) that improve physical function and bone health without adversely affecting the prostate and cardiovascular outcomes. This review describes the historical evolution, the rationale for SARM development, and the mechanisms of testosterone action and SARM selectivity. Although steroidal SARMs have been around since the 1940s, a number of nonsteroidal SARMs that do not serve as substrates for CYP19 aromatase or 5alpha-reductase, act as full agonists in muscle and bone and as partial agonists in prostate are in development. The differing interactions of steroidal and nonsteroidal compounds with androgen receptor (AR) contribute to their unique pharmacologic actions. Ligand binding induces specific conformational changes in the ligand-binding domain, which could modulate surface topology and protein-protein interactions between AR and coregulators, resulting in tissue-specific gene regulation. Preclinical studies have demonstrated the ability of SARMs to increase muscle and bone mass in preclinical rodent models with varying degree of prostate sparing. Phase I trials of SARMs in humans have reported modest increments in fat-free mass. SARMs hold promise as a new class of function promoting anabolic therapies for a number of clinical indications, including functional limitations associated with aging and chronic disease, frailty, cancer cachexia, and osteoporosis.

Selective Androgen Receptor Modulators (SARMs) as Function Promoting Therapies

PubMed Central

Bhasin, Shalender; Jasuja, Ravi

2010-01-01

Purpose of review The last decade has witnessed unprecedented discovery effort to develop selective androgen receptor modulators (SARMs) that improve physical function and bone health without adversely affecting the prostate and cardiovascular outcomes. This review describes the historical evolution, the rationale for SARM development, and the mechanisms of testosterone action and SARM selectivity. Recent Findings While steroidal SARMs have been around since the 1940s, a number of nonsteroidal SARMs that do not serve as substrates for CYP19 aromatase or 5α-reductase, act as full agonists in muscle and bone and as partial agonists in prostate are in development. The differing interactions of steroidal and nonsteroidal compounds with AR contribute to their unique pharmacologic actions. Ligand binding induces specific conformational changes in the ligand binding domain, which could modulate surface topology and protein-protein interactions between AR and coregulators, resulting in tissue-specific gene regulation. Preclinical studies have demonstrated the ability of SARMs to increase muscle and bone mass in preclinical rodent models with varying degree of prostate sparing. Phase I trials of SARMs in humans have reported modest increments in fat-free mass. Summary SARMs hold promise as a new class of function promoting anabolic therapies for a number of clinical indications, including functional limitations associated with aging and chronic disease, frailty, cancer cachexia, and osteoporosis. PMID:19357508

Mass eigenstates in bimetric theory with matter coupling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt-May, Angnis, E-mail: angnis.schmidt-may@fysik.su.se

2015-01-01

In this paper we study the ghost-free bimetric action extended by a recently proposed coupling to matter through a composite metric. The equations of motion for this theory are derived using a method which avoids varying the square-root matrix that appears in the matter coupling. We make an ansatz for which the metrics are proportional to each other and find that it can solve the equations provided that one parameter in the action is fixed. In this case, the proportional metrics as well as the effective metric that couples to matter solve Einstein's equations of general relativity including a mattermore » source. Around these backgrounds we derive the quadratic action for perturbations and diagonalize it into generalized mass eigenstates. It turns out that matter only interacts with the massless spin-2 mode whose equation of motion has exactly the form of the linearized Einstein equations, while the field with Fierz-Pauli mass term is completely decoupled. Hence, bimetric theory, with one parameter fixed such that proportional solutions exist, is degenerate with general relativity up to linear order around these backgrounds.« less

Implementation of Mass Cytometry as a Tool for Mechanism of Action Studies in Inflammatory Bowel Disease.

PubMed

Tyler, Christopher J; Pérez-Jeldres, Tamara; Ehinger, Erik; Capaldo, Brian; Karuppuchamy, Thangaraj; Boyer, Joshua D; Patel, Derek; Dulai, Parambir; Boland, Brigid S; Lannigan, Joanne; Eckmann, Lars; Ernst, Peter B; Sandborn, William J; Ho, Samuel B; Rivera-Nieves, Jesús

2018-06-08

Novel therapeutics for inflammatory bowel disease (IBD) are under development, yet mechanistic readouts at the tissue level are lacking. Techniques to assess intestinal immune composition could represent a valuable tool for mechanism of action (MOA) studies of novel drugs. Mass cytometry enables analysis of intestinal inflammatory cell infiltrate and corresponding molecular fingerprints with unprecedented resolution. Here, we aimed to optimize the methodology for isolation and cryopreservation of cells from intestinal tissue to allow for the potential implementation of mass cytometry in MOA studies. We investigated key technical issues, including minimal tissue requirements, cell isolation protocols, and cell storage, using intestinal biopsies and peripheral blood from healthy individuals. High-dimensional mass cytometry was employed for the analyses of biopsy-derived intestinal cellular subsets. Dithiothreitol and mechanical dissociation decreased epithelial cell contamination and allowed for isolation of adequate cell numbers from 2 to 4 colonic or ileal biopsies (6 × 104±2 × 104) after a 20-minute collagenase digestion, allowing for reliable detection of most major immune cell subsets. Biopsies and antibody-labeled mononuclear cells could be cryopreserved for later processing and acquisition (viability > 70%; P < 0.05). Mass cytometry represents a unique tool for deep immunophenotyping intestinal cell composition. This technique has the potential to facilitate analysis of drug actions at the target tissue by identifying specific cellular subsets and their molecular signatures. Its widespread implementation may impact not only IBD research but also other gastrointestinal conditions where inflammatory cells play a role in pathogenesis.

Dynamic optimization and adaptive controller design

NASA Astrophysics Data System (ADS)

Inamdar, S. R.

2010-10-01

In this work I present a new type of controller which is an adaptive tracking controller which employs dynamic optimization for optimizing current value of controller action for the temperature control of nonisothermal continuously stirred tank reactor (CSTR). We begin with a two-state model of nonisothermal CSTR which are mass and heat balance equations and then add cooling system dynamics to eliminate input multiplicity. The initial design value is obtained using local stability of steady states where approach temperature for cooling action is specified as a steady state and a design specification. Later we make a correction in the dynamics where material balance is manipulated to use feed concentration as a system parameter as an adaptive control measure in order to avoid actuator saturation for the main control loop. The analysis leading to design of dynamic optimization based parameter adaptive controller is presented. The important component of this mathematical framework is reference trajectory generation to form an adaptive control measure.

Remediation and its effect represented on long term monitoring data at a chlorinated ethenes contaminated site, Wonju, Korea

NASA Astrophysics Data System (ADS)

Lee, Seong-Sun; Lee, Seung Hyun; Lee, Kang-Kun

2016-04-01

A research for the contamination of chlorinated ethenes such as trichloroethylene (TCE) at an industrial complex, Wonju, Korea, was carried out based on 17 rounds of groundwater quality data collection from 2009 to 2015. Remediation technologies such as soil vapor extraction, soil flushing, biostimulation, and pump-and-treat have been applied to eliminate the contaminant sources of trichloroethylene (TCE) and to prevent the migration of TCE plume from remediation target zones to groundwater discharge area like a stream. The remediation efficiency according to the remedial actions was evaluated by tracing a time-series of plume evaluation and temporal mass discharge at three transects (Source, Transect-1, Transect-2) which was assigned along the groundwater flow path. Also, based on long term monitoring data, dissolved TCE concentration and mass of residual TCE in the initial stage of disposal were estimated to evaluate the efficiency of in situ remediation. The results of temporal and spatial monitoring before remedial actions showed that a TCE plume originating from main and local source zones continues to be discharged to a stream. However, from the end of intensive remedial actions from 2012 to 2013, the aqueous concentrations of TCE plume present at and around the main source areas decreased significantly. Especially, during the intensive remediation period, the early average mass discharge (26.58 g/day) at source transect was decreased to average 4.99 g/day. Estimated initial dissolved concentration and residual mass of TCE in the initial stage of disposal decreased rapidly after an intensive remedial action in 2013 and it is expected to be continuously decreased from the end of remedial actions to 2020. This study demonstrates that long term monitoring data are useful in assessing the effectiveness of remedial actions at chlorinated ethenes contaminated site. Acknowledgements This project is supported by the Korea Ministry of Environment under "The GAIA Project (173-092-009)"and "R&D Project on Environmental Management of Geologic CO2 storage" from the KEITI (Project number:2014001810003).

Disease invasion risk in a growing population.

PubMed

Yuan, Sanling; van den Driessche, P; Willeboordse, Frederick H; Shuai, Zhisheng; Ma, Junling

2016-09-01

The spread of an infectious disease may depend on the population size. For simplicity, classic epidemic models assume homogeneous mixing, usually standard incidence or mass action. For standard incidence, the contact rate between any pair of individuals is inversely proportional to the population size, and so the basic reproduction number (and thus the initial exponential growth rate of the disease) is independent of the population size. For mass action, this contact rate remains constant, predicting that the basic reproduction number increases linearly with the population size, meaning that disease invasion is easiest when the population is largest. In this paper, we show that neither of these may be true on a slowly evolving contact network: the basic reproduction number of a short epidemic can reach its maximum while the population is still growing. The basic reproduction number is proportional to the spectral radius of a contact matrix, which is shown numerically to be well approximated by the average excess degree of the contact network. We base our analysis on modeling the dynamics of the average excess degree of a random contact network with constant population input, proportional deaths, and preferential attachment for contacts brought in by incoming individuals (i.e., individuals with more contacts attract more incoming contacts). In addition, we show that our result also holds for uniform attachment of incoming contacts (i.e., every individual has the same chance of attracting incoming contacts), and much more general population dynamics. Our results show that a disease spreading in a growing population may evade control if disease control planning is based on the basic reproduction number at maximum population size.

Non-Disruptive Tactics of Suppression Are Superior in Countering Terrorism, Insurgency, and Financial Panics

PubMed Central

Siegel, David A.

2011-01-01

Background Suppressing damaging aggregate behaviors such as insurgency, terrorism, and financial panics are important tasks of the state. Each outcome of these aggregate behaviors is an emergent property of a system in which each individual's action depends on a subset of others' actions, given by each individual's network of interactions. Yet there are few explicit comparisons of strategies for suppression, and none that fully incorporate the interdependence of individual behavior. Methods and Findings Here I show that suppression tactics that do not require the removal of individuals from networks of interactions are nearly always more effective than those that do. I find using simulation analysis of a general model of interdependent behavior that the degree to which such less disruptive suppression tactics are superior to more disruptive ones increases in the propensity of individuals to engage in the behavior in question. Conclusions Thus, hearts-and-minds approaches are generally more effective than force in counterterrorism and counterinsurgency, and partial insurance is usually a better tactic than gag rules in quelling financial panics. Differences between suppression tactics are greater when individual incentives to support terrorist or insurgent groups, or susceptibilities to financial panic, are higher. These conclusions have utility for policy-makers seeking to end bloody conflicts and prevent financial panics. As the model also applies to mass protest, its conclusions provide insight as well into the likely effects of different suppression strategies undertaken by authoritarian regimes seeking to hold on to power in the face of mass movements seeking to end them. PMID:21533247

Discovery of New Retrograde Substructures: The Shards of ω Centauri?

NASA Astrophysics Data System (ADS)

Myeong, G. C.; Evans, N. W.; Belokurov, V.; Sanders, J. L.; Koposov, S. E.

2018-06-01

We use the SDSS-Gaia catalogue to search for substructure in the stellar halo. The sample comprises 62 133 halo stars with full phase space coordinates and extends out to heliocentric distances of ˜10 kpc. As actions are conserved under slow changes of the potential, they permit identification of groups of stars with a common accretion history. We devise a method to identify halo substructures based on their clustering in action space, using metallicity as a secondary check. This is validated against smooth models and numerical constructed stellar halos from the Aquarius simulations. We identify 21 substructures in the SDSS-Gaia catalogue, including 7 high significance, high energy and retrograde ones. We investigate whether the retrograde substructures may be material stripped off the atypical globular cluster ω Centauri. Using a simple model of the accretion of the progenitor of the ω Centauri, we tentatively argue for the possible association of up to 5 of our new substructures (labelled Rg1, Rg3, Rg4, Rg6 and Rg7) with this event. This sets a minimum mass of 5× 108M⊙ for the progenitor, so as to bring ω Centauri to its current location in action - energy space. Our proposal can be tested by high resolution spectroscopy of the candidates to look for the unusual abundance patterns possessed by ω Centauri stars.

Physical activity among adults with obesity: testing the Health Action Process Approach.

PubMed

Parschau, Linda; Barz, Milena; Richert, Jana; Knoll, Nina; Lippke, Sonia; Schwarzer, Ralf

2014-02-01

This study tested the applicability of the Health Action Process Approach (HAPA) in a sample of obese adults in the context of physical activity. Physical activity was assessed along with motivational and volitional variables specified in the HAPA (motivational self-efficacy, outcome expectancies, risk perception, intention, maintenance self-efficacy, action planning, coping planning, recovery self-efficacy, social support) in a sample of 484 obese men and women (body mass index ≥ 30 kg/m2). Applying structural equation modeling, the fit of the HAPA model was satisfactory-χ²(191) = 569.93, p < .05, χ²/df = 2.98, comparative fit index = .91, normed-fit index = .87, and root mean square error of approximation = .06 (90% CI = .06, .07)-explaining 30% of the variance in intention and 18% of the variance in physical activity. Motivational self-efficacy, outcome expectancies, and social support were related to intention. An association between maintenance self-efficacy and coping planning was found. Recovery self-efficacy and social support were associated with physical activity. No relationships were found between risk perception and intention and between planning and physical activity. The assumptions derived from the HAPA were partly confirmed and the HAPA may, therefore, constitute a theoretical backdrop for intervention designs to promote physical activity in adults with obesity. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Simulations of temporal patterns of oral airflow in men and women using a two-mass model of the vocal folds under dynamic control

NASA Astrophysics Data System (ADS)

Lucero, Jorge C.; Koenig, Laura L.

2005-03-01

In this study we use a low-dimensional laryngeal model to reproduce temporal variations in oral airflow produced by speakers in the vicinity of an abduction gesture. It attempts to characterize these temporal patterns in terms of biomechanical parameters such as glottal area, vocal fold stiffness, subglottal pressure, and gender differences in laryngeal dimensions. A two-mass model of the vocal folds coupled to a two-tube approximation of the vocal tract is fitted to oral airflow records measured in men and women during the production of /aha/ utterances, using the subglottal pressure, glottal width, and Q factor as control parameters. The results show that the model is capable of reproducing the airflow records with good approximation. A nonlinear damping characteristics is needed, to reproduce the flow variation at glottal abduction. Devoicing is achieved by the combined action of vocal fold abduction, the decrease of subglottal pressure, and the increase of vocal fold tension. In general, the female larynx has a more restricted region of vocal fold oscillation than the male one. This would explain the more frequent devoicing in glottal abduction-adduction gestures for /h/ in running speech by women, compared to men. .

Nucleon Structure from 2+1 Flavor Domain Wall QCD at Nearly Physical Pion Mass

NASA Astrophysics Data System (ADS)

Ohta, Shigemi

2011-05-01

The RBC and UKQCD collaborations have been investigating hadron physics in numerical lattice quantum chromodynamics (QCD) with (2+1) flavors of dynamical domain wall fermions (DWF) quarks that preserves continuum-like chiral and flavor symmetries. The strange quark mass is adjusted to physical value via reweighting and degenerate up and down quark masses are set as light as possible. In a recent study of nucleon structure we found a strong dependence on pion mass and lattice spatial extent in isovector axialvector-current form factors. This is likely the first credible evidence for the pion cloud surrounding nucleon. Here we report the status of nucleon structure calculations with a new (2+1)-flavor dynamical DWF ensembles with much lighter pion mass of 180 and 250 MeV and a much larger lattice spatial exent of 4.6 fm. A combination of the Iwasaki and dislocation-suppressing-determinant-ratio (I+DSDR) gauge action and DWF fermion action allows us to generate these ensembles at cutoff of about 1.4 GeV while keeping the residual breaking of chiral symmetry sufficiently small. Nucleon source Gaussian smearing has been optimized. Preliminary nucleon mass estimates are 0.98 and 1.05 GeV.

Rapidly Growing Brtl/+ Mouse Model of Osteogenesis Imperfecta Improves Bone Mass and Strength with Sclerostin Antibody Treatment

PubMed Central

Sinder, Benjamin P.; Salemi, Joseph D.; Ominsky, Michael S.; Caird, Michelle S.; Marini, Joan C.; Kozloff, Kenneth M.

2014-01-01

Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk that presents most severely in children. Anti-resorptive bisphosphonates are frequently used to treat pediatric OI and controlled clinical trials have shown bisphosphonate therapy improves vertebral outcomes but has little benefit on long bone fracture rate. New treatments which increase bone mass throughout the pediatric OI skeleton would be beneficial. Sclerostin antibody (Scl-Ab) is a potential candidate anabolic therapy for pediatric OI and functions by stimulating osteoblastic bone formation via the canonical wnt signaling pathway. To explore the effect of Scl-Ab on the rapidly growing OI skeleton, we treated rapidly growing 3 week old Brtl/+ mice, harboring a typical heterozygous OI-causing Gly->Cys substitution on col1a1, for 5 weeks with Scl-Ab. Scl-Ab had anabolic effects in Brtl/+ and led to new cortical bone formation and increased cortical bone mass. This anabolic action resulted in improved mechanical strength to WT Veh levels without altering the underlying brittle nature of the material. While Scl-Ab was anabolic in trabecular bone of the distal femur in both genotypes, the effect was less strong in these rapidly growing Brtl/+ mice compared to WT. In conclusion, Scl-Ab was able to stimulate bone formation in a rapidly growing Brtl/+ murine model of OI, and represents a potential new therapy to improve bone mass and reduce fracture risk in pediatric OI. PMID:25445450

Consequences of an uncertain mass mortality regime triggered by climate variability on giant clam population management in the Pacific Ocean.

PubMed

Van Wynsberge, Simon; Andréfouët, Serge; Gaertner-Mazouni, Nabila; Remoissenet, Georges

2018-02-01

Despite actions to manage sustainably tropical Pacific Ocean reef fisheries, managers have faced failures and frustrations because of unpredicted mass mortality events triggered by climate variability. The consequences of these events on the long-term population dynamics of living resources need to be better understood for better management decisions. Here, we use a giant clam (Tridacna maxima) spatially explicit population model to compare the efficiency of several management strategies under various scenarios of natural mortality, including mass mortality due to climatic anomalies. The model was parameterized by in situ estimations of growth and mortality and fishing effort, and was validated by historical and new in situ surveys of giant clam stocks in two French Polynesia lagoons. Projections on the long run (100 years) suggested that the best management strategy was a decrease of fishing pressure through quota implementation, regardless of the mortality regime considered. In contrast, increasing the minimum legal size of catch and closing areas to fishing were less efficient. When high mortality occurred due to climate variability, the efficiency of all management scenarios decreased markedly. Simulating El Niño Southern Oscillation event by adding temporal autocorrelation in natural mortality rates increased the natural variability of stocks, and also decreased the efficiency of management. These results highlight the difficulties that managers in small Pacific islands can expect in the future in the face of global warming, climate anomalies and new mass mortalities. Copyright © 2017 Elsevier Inc. All rights reserved.

Derivation of a first order approximation of particulate matter from aircraft

DOT National Transportation Integrated Search

2003-06-22

The mass of particulate matter (PM) emitted from aircraft must be predicted for major : actions at airports to comply with current federal regulations. However, this PM mass in : the jet exhaust has not been effectively quantified to permit accurate ...

77 FR 61048 - Agency Information Collection Activity Under OMB Review

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-05

... Information Collection Activity Under OMB Review AGENCY: Federal Transit Administration, DOT. ACTION: Notice... necessary to determine eligibility of applicants and ensure mass transportation service at a minimum cost... will improve mass transportation service or help transportation service meet the total urban...

Research on vibration characteristics of gun barrel based on contact model

NASA Astrophysics Data System (ADS)

Zhao, Yang; Zhou, Qizheng; Yue, Pengfei

2017-04-01

In order to study vibration characteristics of the gun barrel under the action of moving projectile, the gun barrel is simplified to cross sectional cantilever beam such as Euler. Considering contact conditions of inertia effect and projectile with the gun barrel, the equation of lateral vibration of the gun barrel is established under the projectile-gun coupling effect; the modal analysis method is used to give the analytic solutions of equation series. The effect of the motion parameters the projectile on the vibration of gun barrel is discussed, and characteristics of vibration of gun barrel are further studied under two conditions of repeating and projectile with mass eccentricity. The research results show that reasonable control of the acceleration of the projectile in the gun bore, and reduction of projectile mass eccentricity can help reduce the muzzle vibration at the gun firing. The research results can provide reference for overall design of the gun, and the modeling and analysis method used in the paper can be promoted for the solution of vibration of other related projects under the moving excitation.

UV Photodissociation Action Spectroscopy of Haloanilinium Ions in a Linear Quadrupole Ion Trap Mass Spectrometer

NASA Astrophysics Data System (ADS)

Hansen, Christopher S.; Kirk, Benjamin B.; Blanksby, Stephen J.; O'Hair, Richard. A. J.; Trevitt, Adam J.

2013-06-01

UV-vis photodissociation action spectroscopy is becoming increasingly prevalent because of advances in, and commercial availability of, ion trapping technologies and tunable laser sources. This study outlines in detail an instrumental arrangement, combining a commercial ion-trap mass spectrometer and tunable nanosecond pulsed laser source, for performing fully automated photodissociation action spectroscopy on gas-phase ions. The components of the instrumentation are outlined, including the optical and electronic interfacing, in addition to the control software for automating the experiment and performing online analysis of the spectra. To demonstrate the utility of this ensemble, the photodissociation action spectra of 4-chloroanilinium, 4-bromoanilinium, and 4-iodoanilinium cations are presented and discussed. Multiple photoproducts are detected in each case and the photoproduct yields are followed as a function of laser wavelength. It is shown that the wavelength-dependent partitioning of the halide loss, H loss, and NH3 loss channels can be broadly rationalized in terms of the relative carbon-halide bond dissociation energies and processes of energy redistribution. The photodissociation action spectrum of (phenyl)Ag2 + is compared with a literature spectrum as a further benchmark.

The Stanford Nutrition Action Program: a dietary fat intervention for low-literacy adults.

PubMed Central

Howard-Pitney, B; Winkleby, M A; Albright, C L; Bruce, B; Fortmann, S P

1997-01-01

OBJECTIVES: This study was undertaken to test the effectiveness of the Stanford Nutrition Action Program, an experimental trial to reduce dietary fat intake among low-literacy, low-income adults. METHODS: Twenty-four paired adult education classes (351 participants, 85% women, mean age = 31 years) were randomly assigned to receive a newly developed dietary fat curriculum (the Stanford Nutrition Action Program) or an existing general nutrition curriculum. Food frequency and nutrition-related data, body mass index, and capillary blood cholesterol were collected at baseline and at two postintervention follow-ups. RESULTS: The Stanford Nutrition Action Program classes showed significantly greater net improvements in nutrition knowledge (+7.7), attitudes (/0.2), and self-efficacy (-0.2) than the general nutrition classes; they also showed significantly greater reductions in the percentage of calories from total (-2.3%) and saturated (-0.9%) fat. There were no significant differences in body mass index or blood cholesterol. All positive intervention effects were maintained for 3 months postintervention. CONCLUSIONS: The Stanford Nutrition Action Program curriculum, tailored to the cultural, economic, and learning needs of low-literacy, low-income adults, was significantly more effective in achieving fat-related nutritional changes than the general nutrition curriculum. PMID:9431286

Performance of an inverted pendulum model directly applied to normal human gait.

PubMed

Buczek, Frank L; Cooney, Kevin M; Walker, Matthew R; Rainbow, Michael J; Concha, M Cecilia; Sanders, James O

2006-03-01

In clinical gait analysis, we strive to understand contributions to body support and propulsion as this forms a basis for treatment selection, yet the relative importance of gravitational forces and joint powers can be controversial even for normal gait. We hypothesized that an inverted pendulum model, propelled only by gravity, would be inadequate to predict velocities and ground reaction forces during gait. Unlike previous ballistic and passive dynamic walking studies, we directly compared model predictions to gait data for 24 normal children. We defined an inverted pendulum from the average center-of-pressure to the instantaneous center-of-mass, and derived equations of motion during single support that allowed a telescoping action. Forward and inverse dynamics predicted pendulum velocities and ground reaction forces, and these were statistically and graphically compared to actual gait data for identical strides. Results of forward dynamics replicated those in the literature, with reasonable predictions for velocities and anterior ground reaction forces, but poor predictions for vertical ground reaction forces. Deviations from actual values were explained by joint powers calculated for these subjects. With a telescoping action during inverse dynamics, predicted vertical forces improved dramatically and gained a dual-peak pattern previously missing in the literature, yet expected for normal gait. These improvements vanished when telescoping terms were set to zero. Because this telescoping action is difficult to explain without muscle activity, we believe these results support the need for both gravitational forces and joint powers in normal gait. Our approach also begins to quantify the relative contributions of each.

Passive versus active engulfment: verdict from trajectory simulations of lunge-feeding fin whales Balaenoptera physalus

PubMed Central

Potvin, J.; Goldbogen, J. A.; Shadwick, R. E.

2009-01-01

Lunge-feeding in rorqual whales represents the largest biomechanical event on Earth and one of the most extreme feeding methods among aquatic vertebrates. By accelerating to high speeds and by opening their mouth to large gape angles, these whales generate the water pressure required to expand their mouth around a large volume of prey-laden water. Such large influx is facilitated by highly extensible ventral groove blubber (VGB) associated with the walls of the throat (buccal cavity). Based on the mechanical properties of this tissue, previous studies have assumed lunge-feeding to be an entirely passive process, where the flow-induced pressure driving the expansion of the VGB is met with little resistance. Such compliant engulfment would be facilitated by the compliant properties of the VGB that have been measured on dead specimens. However, adjoining the ventral blubber are several layers of well-developed muscle embedded with mechanoreceptors, thereby suggesting a capability to gauge the magnitude of engulfed water and use eccentric muscle action to control the flux of water into the mouth. An unsteady hydrodynamic model of fin whale lunge-feeding is presented here to test whether engulfment is exclusively passive and compliant or involves muscle action. The model is based on the explicit simulation of the engulfed water as it interacts with the buccal cavity walls of the whale, under different heuristically motivated cavity forces. Our results, together with their comparison with velocity data collected in the field, suggest that adult rorquals actively push engulfed water forward from the very onset of mouth opening in order to successfully complete a lunge. Interestingly, such an action involves a reflux of the engulfed mass rather than the oft-assumed rebound, which would occur mainly at the very end of a lunge sequence dominated by compliant engulfment. Given the great mass of the engulfed water, reflux creation adds a significant source of hydrodynamic drag to the lunge process, but with the benefit of helping to circumvent the problem of removing prey from baleen by enhancing the efficiency of cross-flow filtration after mouth closing. Reflux management for a successful lunge will therefore demand well-coordinated muscular actions of the tail, mouth and ventral cavity. PMID:19158011

Nonlinear multidimensional cosmological models with form fields: Stabilization of extra dimensions and the cosmological constant problem

NASA Astrophysics Data System (ADS)

Günther, U.; Moniz, P.; Zhuk, A.

2003-08-01

We consider multidimensional gravitational models with a nonlinear scalar curvature term and form fields in the action functional. In our scenario it is assumed that the higher dimensional spacetime undergoes a spontaneous compactification to a warped product manifold. Particular attention is paid to models with quadratic scalar curvature terms and a Freund-Rubin-like ansatz for solitonic form fields. It is shown that for certain parameter ranges the extra dimensions are stabilized. In particular, stabilization is possible for any sign of the internal space curvature, the bulk cosmological constant, and of the effective four-dimensional cosmological constant. Moreover, the effective cosmological constant can satisfy the observable limit on the dark energy density. Finally, we discuss the restrictions on the parameters of the considered nonlinear models and how they follow from the connection between the D-dimensional and the four-dimensional fundamental mass scales.

Antigravity: Spin-gravity coupling in action

NASA Astrophysics Data System (ADS)

Plyatsko, Roman; Fenyk, Mykola

2016-08-01

The typical motions of a spinning test particle in Schwarzschild's background which show the strong repulsive action of the highly relativistic spin-gravity coupling are considered using the exact Mathisson-Papapetrou equations. An approximated approach to choice solutions of these equations which describe motions of the particle's proper center of mass is developed.

20 CFR 408.1004 - Which administrative actions are not initial determinations?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Which administrative actions are not initial determinations? 408.1004 Section 408.1004 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR... federally administered State recognition payments due to a State-initiated mass change, as defined in § 408...

Liver-derived IGF-I contributes to GH-dependent increases in lean mass and bone mineral density in mice with comparable levels of circulating GH.

PubMed

Nordstrom, Sarah M; Tran, Jennifer L; Sos, Brandon C; Wagner, Kay-Uwe; Weiss, Ethan J

2011-07-01

The relative contributions of circulating and locally produced IGF-I in growth remain controversial. The majority of circulating IGF-I is produced by the liver, and numerous mouse models have been developed to study the endocrine actions of IGF-I. A common drawback to these models is that the elimination of circulating IGF-I disrupts a negative feedback pathway, resulting in unregulated GH secretion. We generated a mouse with near total abrogation of circulating IGF-I by disrupting the GH signaling mediator, Janus kinase (JAK)2, in hepatocytes. We then crossed these mice, termed JAK2L, to GH-deficient little mice (Lit). Compound mutant (Lit-JAK2L) and control (Lit-Con) mice were treated with equal amounts of GH such that the only difference between the two groups was hepatic GH signaling. Both groups gained weight in response to GH but there was a reduction in the final weight of GH-treated Lit-JAK2L vs. Lit-Con mice. Similarly, lean mass increased in both groups, but there was a reduction in the final lean mass of Lit-JAK2L vs. Lit-Con mice. There was an equivalent increase in skeletal length in response to GH in Lit-Con and Lit-JAK2L mice. There was an increase in bone mineral density (BMD) in both groups, but Lit-JAK2L had lower BMD than Lit-Con mice. In addition, GH-mediated increases in spleen and kidney mass were absent in Lit-JAK2L mice. Taken together, hepatic GH-dependent production of IGF-I had a significant and nonredundant role in GH-mediated acquisition of lean mass, BMD, spleen mass, and kidney mass; however, skeletal length was dependent upon or compensated for by locally produced IGF-I.

Potential description of the charmonium from lattice QCD

NASA Astrophysics Data System (ADS)

Kawanai, Taichi; Sasaki, Shoichi

2016-01-01

We present spin-independent and spin-spin interquark potentials for charmonium states, that are calculated using a relativistic heavy quark action for charm quarks on the PACS-CS gauge configurations generated with the Iwasaki gauge action and 2+1 flavors of Wilson clover quark. The interquark potential with finite quark masses is defined through the equal-time Bethe-Salpeter amplitude. The light and strange quark masses are close to the physical point where the pion mass corresponds to Mπ ≈ 156(7) MeV, and charm quark mass is tuned to reproduce the experimental values of ηc and J/ψ states. Our simulations are performed with a lattice cutoff of a-1 ≈ 2.2 GeV and a spatial volume of (3 fm)3. We solve the nonrelativistic Schrödinger equation with resulting charmonium potentials as theoretical inputs. The resultant charmonium spectrum below the open charm threshold shows a fairly good agreement with experimental data of well-established charmonium states.

Use of inerter devices for weight reduction of tuned mass-dampers for seismic protection of multi-story building: the Tuned Mass-Damper-Interter (TMDI)

NASA Astrophysics Data System (ADS)

Giaralis, Agathoklis; Marian, Laurentiu

2016-04-01

This paper explores the practical benefits of the recently proposed by the authors tuned mass-damper-inerter (TMDI) visà- vis the classical tuned mass-damper (TMD) for the passive vibration control of seismically excited linearly building structures assumed to respond linearly. Special attention is focused on showcasing that the TMDI requires considerably reduced attached mass/weight to achieve the same vibration suppression level as the classical TMD by exploiting the mass amplification effect of the ideal inerter device. The latter allows for increasing the inertial property of the TMDI without a significant increase to its physical weight. To this end, novel numerical results pertaining to a seismically excited 3-storey frame building equipped with optimally designed TMDIs for various values of attached mass and inertance (i.e., constant of proportionality of the inerter resisting force in mass units) are furnished. The seismic action is modelled by a non-stationary stochastic process compatible with the elastic acceleration response spectrum of the European seismic code (Eurocode 8), while the TMDIs are tuned to minimize the mean square top floor displacement. It is shown that the TMDI achieves the same level of performance as an unconventional "large mass" TMD for seismic protection (i.e., more than 10% of attached mass of the total building mass), by incorporating attached masses similar to the ones used for controlling wind-induced vibrations via TMDs (i.e., 1%-5% of the total building mass). Moreover, numerical data from response history analyses for a suite of Eurocode 8 compatible recorded ground motions further demonstrate that optimally tuned TMDIs for top floor displacement minimization achieve considerable reductions in terms of top floor acceleration and attached mass displacement (stroke) compared to the classical TMD with the same attached mass.

Wild capuchin monkeys spontaneously adjust actions when using hammer stones of different mass to crack nuts of different resistance.

PubMed

Liu, Qing; Fragaszy, Dorothy M; Visalberghi, Elisabetta

2016-09-01

Expert tool users are known to adjust their actions skillfully depending on aspects of tool type and task. We examined if bearded capuchin monkeys cracking nuts with stones of different mass adjusted the downward velocity and the height of the stone when striking palm nuts. During a field experiment carried out in FBV (Piauí, Brazil), eight adult wild capuchin monkeys (five males) cracked Orbygnia nuts of varied resistance with hammer stones differing in mass. From recorded videos, we identified the highest strike per nut-cracking episode, and for this strike, we calculated the height to which the monkey lifted the stone, the maximum velocity of the stone during the downward phase, the work done on the stone, and the kinetic energy of the strike. We found that individual capuchins achieved average maximum kinetic energy of 8.7-16.1 J when using stones between 0.9 and 1.9 kg, and maximum kinetic energy correlated positively with mass of the stone. Monkeys lifted all the stones to an individually consistent maximum height but added more work to the stone when using lighter stones. One male and one female monkey lifted stones higher when they cracked more resistant nuts. The high resistance of the Orbygnia nut elicits production of maximum kinetic energy, which the monkeys modulate to some degree by adding work to lighter stones. Capuchin monkeys, like chimpanzees, modulate their actions in nut-cracking, indicating skilled action, although neither species regulates kinetic energy as precisely as skilled human stone knappers. Kinematic analyses promise to yield new insights into the ways and extent to which nonhuman tool users develop expertise. Am J Phys Anthropol 161:53-61, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Zearalenone reduction by commercial peroxidase enzyme and peroxidases from soybean bran and rice bran.

PubMed

Garcia, Sabrina O; Feltrin, Ana Carla P; Garda-Buffon, Jaqueline

2018-06-11

The peroxidase (POD) enzyme, obtained from different sources, has been described in the literature regarding its good results of reduction in concentration or degradation levels of mycotoxins, such as aflatoxin B1, deoxynivalenol and zearalenone. This study aimed at evaluating the action of commercial peroxidase and peroxidase from soybean bran (SB) and rice bran (RB) in zearalenone (ZEA) reduction in a model solution and the characterization of the mechanism of enzyme action. POD was extracted from SB and RB in phosphate buffer by orbital agitation. Evaluation of the action of commercial POD and POD from SB and RB in ZEA reduction was carried out in phosphate buffer and aqueous solution, respectively. Parameters of K M and V max were determined in the concentration range from 0.16 to 6 µg mL -1 . ZEA reduction was determined and the mechanism of enzyme action was characterized by Fourier transform infrared spectroscopy and high-pressure liquid chromatography-electrospray tandem mass spectrometry. Commercial POD and POD from RB and SB reduced ZEA concentration by 69.9, 47.4 and 30.6% in 24 h, respectively. K M values were 39.61 and 8.90 µM whereas V max values were 0.170 and 0.011 µM min -1 for commercial POD and POD from RB, respectively. The characterization of the mechanism of enzyme action showed the oxidoreductive action of commercial POD in the mycotoxin. The use of commercial POD and POD from agro-industrial by-products, such as SB and RB, could be a promising alternative for ZEA biodegradation.

A framework for modeling contaminant impacts on reservoir water quality

NASA Astrophysics Data System (ADS)

Jeznach, Lillian C.; Jones, Christina; Matthews, Thomas; Tobiason, John E.; Ahlfeld, David P.

2016-06-01

This study presents a framework for using hydrodynamic and water quality models to understand the fate and transport of potential contaminants in a reservoir and to develop appropriate emergency response and remedial actions. In the event of an emergency situation, prior detailed modeling efforts and scenario evaluations allow for an understanding of contaminant plume behavior, including maximum concentrations that could occur at the drinking water intake and contaminant travel time to the intake. A case study assessment of the Wachusett Reservoir, a major drinking water supply for metropolitan Boston, MA, provides an example of an application of the framework and how hydrodynamic and water quality models can be used to quantitatively and scientifically guide management in response to varieties of contaminant scenarios. The model CE-QUAL-W2 was used to investigate the water quality impacts of several hypothetical contaminant scenarios, including hypothetical fecal coliform input from a sewage overflow as well as an accidental railway spill of ammonium nitrate. Scenarios investigated the impacts of decay rates, season, and inter-reservoir transfers on contaminant arrival times and concentrations at the drinking water intake. The modeling study highlights the importance of a rapid operational response by managers to contain a contaminant spill in order to minimize the mass of contaminant that enters the water column, based on modeled reservoir hydrodynamics. The development and use of hydrodynamic and water quality models for surface drinking water sources subject to the potential for contaminant entry can provide valuable guidance for making decisions about emergency response and remediation actions.

A novel model of photothermal diffusion (PTD) for polymer nano-composite semiconducting of thin circular plate

NASA Astrophysics Data System (ADS)

Lotfy, Kh.

2018-05-01

In this article, theoretical discussions for a novel mathematical-physical Photothermal diffusion (PTD) model in the generalized thermoelasticity theory with photothermal processes and chemical action are introduced. The mean idea of this model depends on the interaction between quasi-particles (plasma waves) that depends on the kind of the used materials, the mechanical forces acting on the surface, the generalized thermo and mass diffusion (due to coupling of temperature fields with thermal waves and chemical potential) and the elastic waves. The one dimensional Laplace transforms is used to obtain the exact solution for some physical and chemical quantities for a thin circular plate of a semiconducting polymer nanocomposite such as silicon (Si). New variables are deduced and discussed. The obtained results of the physical quantities are presented analytically and illustrated graphically with some important applications.

Development of a global pollution model for CO, CH4, and CH2O

NASA Technical Reports Server (NTRS)

Peters, L. K.

1974-01-01

The current status of a global pollution model for carbon monoxide, methane, and formaldehyde is described. The physico-chemical action is considered of these three pollutants in the troposphere. This geographic restriction is convenient since the tropopause provides a natural boundary across which little transport occurs. The data on sources and sinks for these pollutants is based on available information and assumptions relative to the major man-made and natural contributions. The distributions and concentrations of methane, formaldehyde, and carbon monoxide in the atmosphere are interrelated by the chemical reactions in which they participate. A chemical kinetic model based on the pseudo-steady state approximation for the intermediate species was developed to account for these reactions. The numerical procedure used to mathematically describe the pollution transport is a mass conservative scheme employing an integral flux approach.

Grave mapping in support of the search for missing persons in conflict contexts.

PubMed

Congram, Derek; Kenyhercz, Michael; Green, Arthur Gill

2017-09-01

We review the current and potential uses of Geographic Information Software (GIS) and "spatial thinking" for understanding body disposal behaviour in times of mass fatalities, particularly armed conflict contexts. The review includes observations made by the authors during the course of their academic research and professional consulting on the use of spatial analysis and GIS to support Humanitarian Forensic Action (HFA) to search for the dead, theoretical and statistical considerations in modelling grave site locations, and suggestions on how this work may be advanced further. Copyright © 2017 Elsevier B.V. All rights reserved.

Construcción de un catálogo de cúmulos de galaxias en proceso de colisión

NASA Astrophysics Data System (ADS)

de los Ríos, M.; Domínguez, M. J.; Paz, D.

2015-08-01

In this work we present first results of the identification of colliding galaxy clusters in galaxy catalogs with redshift measurements (SDSS, 2DF), and introduce the methodology. We calibrated a method by studying the merger trees of clusters in a mock catalog based on a full-blown semi-analytic model of galaxy formation on top of the Millenium cosmological simulation. We also discuss future actions for studding our sample of colliding galaxy clusters, including x-ray observations and mass reconstruction obtained by using weak gravitational lenses.

B-meson decay constant from unquenched lattice QCD.

PubMed

Gray, Alan; Wingate, Matthew; Davies, Christine T H; Gulez, Emel; Lepage, G Peter; Mason, Quentin; Nobes, Matthew; Shigemitsu, Junko

2005-11-18

We present determinations of the -meson decay constant f(B) and f(B)(s)/f(B) using the MILC Collaboration unquenched gauge configurations, which include three flavors of light sea quarks. The mass of one of the sea quarks is kept around the strange quark mass, and we explore a range in masses for the two lighter sea quarks down to m(s)/8. The heavy quark is simulated using nonrelativistic QCD, and both the valence and sea light quarks are represented by the highly improved (AsqTad) staggered quark action. The good chiral properties of the latter action allow for a more accurate chiral extrapolation to physical up and down quarks than has been possible in the past. We find f(B)=216(9)(19)(4)(6) MeV and f(B)(s)/f(B)=1.20(3)(1).

The role of ghrelin in anorexia-cachexia syndromes.

PubMed

Guillory, Bobby; Splenser, Andres; Garcia, Jose

2013-01-01

Anorexia, sarcopenia, and cachexia are common complications of many chronic conditions including cancer, rheumatoid arthritis, HIV infection, aging, and chronic lung, heart, or kidney disease. Currently, there is no effective treatment for muscle atrophy or wasting conditions although they typically take a significant toll on the quality of life of patients and are associated with poor prognosis and decreased survival. Ghrelin affects multiple key pathways in the regulation of body weight, body composition, and appetite in the setting of cachexia that may lead to an increase in appetite and growth hormone secretion and a reduction in energy expenditure and inflammation. The net effect is increased lean body mass and fat mass preservation. In this chapter, we review the mechanisms of action of ghrelin and present the available data in animal models and human trials using ghrelin or ghrelin mimetics in different settings of cachexia. Copyright © 2013 Published by Elsevier Inc. Published by Elsevier Science & Technology.. All rights reserved.

Predicting the velocity and azimuth of fragments generated by the range destruction or random failure of rocket casings and tankage

NASA Astrophysics Data System (ADS)

Eck, M.; Mukunda, M.

The proliferation of space vehicle launch sites and the projected utilization of these facilities portends an increase in the number of on-pad, ascent, and on-orbit solid-rocket motor (SRM) casings and liquid-rocket tanks which will randomly fail or will fail from range destruct actions. Beyond the obvious safety implications, these failures may have serious resource implications for mission system and facility planners. SRM-casing failures and liquid-rocket tankage failures result in the generation of large, high velocity fragments which may be serious threats to the safety of launch support personnel if proper bunkers and exclusion areas are not provided. In addition, these fragments may be indirect threats to the general public's safety if they encounter hazardous spacecraft payloads which have not been designed to withstand shrapnel of this caliber. They may also become threats to other spacecraft if, by failing on-orbit, they add to the ever increasing space-junk collision cross-section. Most prior attempts to assess the velocity of fragments from failed SRM casings have simply assigned the available chamber impulse to available casing and fuel mass and solved the resulting momentum balance for velocity. This method may predict a fragment velocity which is high or low by a factor of two depending on the ratio of fuel to casing mass extant at the time of failure. Recognizing the limitations of existing methods, the authors devised an analytical approach which properly partitions the available impulse to each major system-mass component. This approach uses the Physics International developed PISCES code to couple the forces generated by an Eulerian modeled gas flow field to a Lagrangian modeled fuel and casing system. The details of a predictive analytical modeling process as well as the development of normalized relations for momentum partition as a function of SRM burn time and initial geometry are discussed in this paper. Methods for applying similar modeling techniques to liquid-tankage-over-pressure failures are also discussed. These methods have been calibrated against observed SRM ascent failures and on-orbit tankage failures. Casing-quadrant sized fragments with velocities exceeding 100 m/s resulted from Titan 34D-SRM range destruct actions at 10 s mission elapsed time (MET). Casing-quadrant sized fragments with velocities of approx. 200 m/s resulted from STS-SRM range destruct actions at 110 s MET. Similar sized fragments for Ariane third stage and Delta second stage tankage were predicted to have maximum velocities of 260 and 480 m/s respectively. Good agreement was found between the predictions and observations for five specific events and it was concluded that the methods developed have good potential for use in predicting the fragmentation process of a number of generically similar casing and tankage systems.

Effects of liraglutide and sibutramine on food intake, palatability, body weight and glucose tolerance in the gubra DIO-rats.

PubMed

Hansen, Gitte; Jelsing, Jacob; Vrang, Niels

2012-02-01

To validate the gubra DIO-rats as a useful animal model of human obesity. The gubra diet-induced obesity (DIO) rat model was based on male Sprague-Dawley rats with ad libitum access to regular chow and a palatable diet rich in fat and sugar. To evaluate the versatility of the gubra DIO-rats as a valid model of human obesity syndrome, the efficacy of 2 weight loss compounds liraglutide and sibutramine with different mechanisms of action were examined in 7-month-old gubra DIO-rats. Liraglutide (200 μg/kg, sc) was administered bi-daily, and sibutramine (5 mg/kg, po) was administered once daily for 23 d. Both the compounds effectively reduced the food intake, body weight and total fat mass as measured by nuclear magnetic resonance. Whereas the 5-HT reuptake inhibitor/5-HT receptor agonist sibutramine reduced the intake of both chow and the gubra-diet, the GLP-1 analogue liraglutide predominantly reduced the intake of the highly palatable diet, indicating a shift in food preference. Sibutramine lowered the insulin sensitivity index, primarily via reductions in glucose-stimulated insulin secretion. This animal model responds well to 2 weight loss compounds with different mechanisms of action. Moreover, the gubra DIO-rat can be particularly useful for the testing of compounds with potential effects on diet preference.

Effects of liraglutide and sibutramine on food intake, palatability, body weight and glucose tolerance in the gubra DIO-rats

PubMed Central

Hansen, Gitte; Jelsing, Jacob; Vrang, Niels

2012-01-01

Aim: To validate the gubra DIO-rats as a useful animal model of human obesity. Methods: The gubra diet-induced obesity (DIO) rat model was based on male Sprague-Dawley rats with ad libitum access to regular chow and a palatable diet rich in fat and sugar. To evaluate the versatility of the gubra DIO-rats as a valid model of human obesity syndrome, the efficacy of 2 weight loss compounds liraglutide and sibutramine with different mechanisms of action were examined in 7-month-old gubra DIO-rats. Liraglutide (200 μg/kg, sc) was administered bi-daily, and sibutramine (5 mg/kg, po) was administered once daily for 23 d. Results: Both the compounds effectively reduced the food intake, body weight and total fat mass as measured by nuclear magnetic resonance. Whereas the 5-HT reuptake inhibitor/5-HT receptor agonist sibutramine reduced the intake of both chow and the gubra-diet, the GLP-1 analogue liraglutide predominantly reduced the intake of the highly palatable diet, indicating a shift in food preference. Sibutramine lowered the insulin sensitivity index, primarily via reductions in glucose-stimulated insulin secretion. Conclusion: This animal model responds well to 2 weight loss compounds with different mechanisms of action. Moreover, the gubra DIO-rat can be particularly useful for the testing of compounds with potential effects on diet preference. PMID:22301859

The simulated effects of wastewater-management actions on the hydrologic system and nitrogen-loading rates to wells and ecological receptors, Popponesset Bay Watershed, Cape Cod, Massachusetts

USGS Publications Warehouse

Walter, Donald A.

2013-01-01

The discharge of excess nitrogen into Popponesset Bay, an estuarine system on western Cape Cod, has resulted in eutrophication and the loss of eel grass habitat within the estuaries. Septic-system return flow in residential areas within the watershed is the primary source of nitrogen. Total Maximum Daily Loads (TMDLs) for nitrogen have been assigned to the six estuaries that compose the system, and local communities are in the process of implementing the TMDLs by the partial sewering, treatment, and disposal of treated wastewater at wastewater-treatment facilities (WTFs). Loads of waste-derived nitrogen from both current (1997–2001) and future sources can be estimated implicitly from parcel-scale water-use data and recharge areas delineated by a groundwater-flow model. These loads are referred to as “instantaneous” loads because it is assumed that the nitrogen from surface sources is delivered to receptors instantaneously and that there is no traveltime through the aquifer. The use of a solute-transport model to explicitly simulate the transport of mass through the aquifer from sources to receptors can improve implementation of TMDLs by (1) accounting for traveltime through the aquifer, (2) avoiding limitations associated with the estimation of loads from static recharge areas, (3) accounting more accurately for the effect of surface waters on nitrogen loads, and (4) determining the response of waste-derived nitrogen loads to potential wastewater-management actions. The load of nitrogen to Popponesset Bay on western Cape Cod, which was estimated by using current sources as input to a solute-transport model based on a steady-state flow model, is about 50 percent of the instantaneous load after about 7 years of transport (loads to estuary are equal to loads discharged from sources); this estimate is consistent with simulated advective traveltimes in the aquifer, which have a median of 5 years. Model-calculated loads originating from recharge areas reach 80 percent of the instantaneous load within 30 years; this result indicates that loads estimated from recharge areas likely are reasonable for estimating current instantaneous loads. However, recharge areas are assumed to remain static as stresses and hydrologic conditions change in response to wastewater-management actions. Sewering of the Popponesset Bay watershed would not change hydraulic gradients and recharge areas to receptors substantially; however, disposal of wastewater from treatment facilities can change hydraulic gradients and recharge areas to nearby receptors, particularly if the facilities are near the boundary of the recharge area. In these cases, nitrogen loads implicitly estimated by using current recharge areas that do not accurately represent future hydraulic stresses can differ significantly from loads estimated with recharge areas that do represent those stresses. Nitrogen loads to two estuaries in the Popponesset Bay system estimated by using recharge areas delineated for future hydrologic conditions and nitrogen sources were about 3 and 9 times higher than loads estimated by using current recharge areas; for this reason, reliance on static recharge areas can present limitations for effective TMDL implementation by means of a hypothetical, but realistic, wastewater-management action. A solute-transport model explicitly represents nitrogen transport from surface sources and does not rely on the use of recharge areas; because changes in gradients resulting from wastewater-management actions are accounted for in transport simulations, they provide more reliable predictions of future nitrogen loads. Explicitly representing the mass transport of nitrogen can better account for the mechanisms by which nitrogen enters the estuary and improve estimates of the attenuation of nitrogen concentrations in fresh surface waters. Water and associated nitrogen can enter an estuary as either direct groundwater discharge or as surface-water inflow. Two estuaries in the Popponesset Bay watershed receive surface-water inflows: Shoestring Bay receives water from the Santuit River, and the tidal reach of the Mashpee River receives water (and associated nitrogen) from the nontidal reach of the Mashpee River. Much of the water discharging into these streams passes through ponds prior to discharge. The additional attenuation of nitrogen in groundwater that has passed through a pond and discharged into a stream prior to entering an estuary is about 3 kilograms per day. Advective-transport times in the aquifer generally are small—median traveltimes are about 4.5 years—and nitrogen loads at receptors respond quickly to wastewater-management actions. The simulated decreases in nitrogen loads were 50 and 80 percent of the total decreases within 5 and 15 years, respectively, after full sewering of the watershed and within 3 and 10 years, for sequential phases of partial sewering and disposal at WTFs. The results show that solute-transport models can be used to assess the responses of nitrogen loads to wastewater-management actions, and that loads at ecological receptors (receiving waters—ponds, streams or coastal waters—that support ecosystems) will respond within a few years to those actions. The responses vary for individual receptors as functions of hydrologic setting, traveltimes in the aquifer, and the unique set of nitrogen sources representing current and future wastewater-disposal actions within recharge areas. Changes in nitrogen loads from groundwater discharge to individual estuaries range from a decrease of 90 percent to an increase of 80 percent following sequential phases of hypothetical but realistic wastewater-management actions. The ability to explicitly represent the transport of mass through the aquifer allows for the evaluation of complex responses that include the effects of surface waters, traveltimes, and complex changes in sources. Most of the simulated decreases in nitrogen loads to Shoestring Bay and the tidal portion of the Mashpee River, 79 and 69 percent, respectively, were caused by decreases in the nitrogen loads from surface-water inflow.

Tachyon condensation and quark mass in the modified Sakai-Sugimoto model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhar, Avinash; High Energy Accelerator Research Organization; Nag, Partha

2008-09-15

This paper continues the investigation of the modified Sakai-Sugimoto model proposed previously [J. High Energy Phys. 01 (2008) 055]. Here we discuss in detail numerical solutions to the classical equations for the brane profile and the tachyon condensate. An ultraviolet cutoff turns out to be essential because the numerical solutions tend to rapidly diverge from the desired asymptotic solutions, beyond a sufficiently large value of the holographic coordinate. The required cutoff is determined by the non-normalizable part of the tachyon and is parametrically far smaller than that dictated by consistency of a description in terms of ten-dimensional bulk gravity. Wemore » had argued [J. High Energy Phys. 01 (2008) 055] that the solution in which the tachyon field goes to infinity at the point where the brane and antibrane meet has only one free parameter, which may be taken to be the asymptotic brane-antibrane separation. Here we present numerical evidence in favor of this observation. We also present evidence that the non-normalizable part of the asymptotic tachyon solution, which is identified with quark mass in the QCD-like boundary theory, is determined by this parameter. We show that the normalizable part of the asymptotic tachyon solution determines the quark condensate, but this requires holographic renormalization of the on-shell boundary brane action because of the presence of infinite cutoff-dependent terms. Our renormalization scheme gives an exponential dependence on the cutoff to the quark mass. We also discuss meson spectra in detail and show that the pion mass is nonzero and satisfies the Gell-Mann-Oakes-Renner relation when a small quark mass is switched on.« less

The ghrelin receptor agonist HM01 mimics the neuronal effects of ghrelin in the arcuate nucleus and attenuates anorexia-cachexia syndrome in tumor-bearing rats.

PubMed

Borner, Tito; Loi, Laura; Pietra, Claudio; Giuliano, Claudio; Lutz, Thomas A; Riediger, Thomas

2016-07-01

The gastric hormone ghrelin positively affects energy balance by increasing food intake and reducing energy expenditure. Ghrelin mimetics are a possible treatment against cancer anorexia-cachexia syndrome (CACS). This study aimed to characterize the action of the nonpeptidergic ghrelin receptor agonist HM01 on neuronal function, energy homeostasis and muscle mass in healthy rats and to evaluate its possible usefulness for the treatment of CACS in a rat tumor model. Using extracellular single-unit recordings, we tested whether HM01 mimics the effects of ghrelin on neuronal activity in the arcuate nucleus (Arc). Furthermore, we assessed the effect of chronic HM01 treatment on food intake (FI), body weight (BW), lean and fat volumes, and muscle mass in healthy rats. Using a hepatoma model, we investigated the possible beneficial effects of HM01 on tumor-induced anorexia, BW loss, muscle wasting, and metabolic rate. HM01 (10(-7)-10(-6) M) mimicked the effect of ghrelin (10(-8) M) by increasing the firing rate in 76% of Arc neurons. HM01 delivered chronically for 12 days via osmotic minipumps (50 μg/h) increased FI in healthy rats by 24%, paralleled by increased BW, higher fat and lean volumes, and higher muscle mass. Tumor-bearing rats treated with HM01 had 30% higher FI than tumor-bearing controls and were protected against BW loss. HM01 treatment resulted in higher muscle mass and fat mass. Moreover, tumor-bearing rats reduced their metabolic rate following HM01 treatment. Our studies substantiate the possible therapeutic usefulness of ghrelin receptor agonists like HM01 for the treatment of CACS and possibly other forms of disease-related anorexia and cachexia. Copyright © 2016 the American Physiological Society.

23 CFR 810.208 - Action by the Federal Highway Administrator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Section 810.208 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PUBLIC TRANSPORTATION MASS TRANSIT AND SPECIAL USE HIGHWAY PROJECTS Making Highway Rights-of-Way Available for Mass... agency under § 810.206 is satisfactory; (b) The public interest will be served thereby; and (c) The...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cartas-Fuentevilla, Roberto; Escalante, Alberto; Germán, Gabriel

Following recent studies which show that it is possible to localize gravity as well as scalar and gauge vector fields in a tachyonic de Sitter thick braneworld, we investigate the solution of the gauge hierarchy problem, the localization of fermion fields in this model, the recovering of the Coulomb law on the non-relativistic limit of the Yukawa interaction between bulk fermions and gauge bosons localized in the brane, and confront the predicted 5D corrections to the photon mass with its upper experimental/observational bounds, finding the model physically viable since it passes these tests. In order to achieve the latter aimsmore » we first consider the Yukawa interaction term between the fermionic and the tachyonic scalar fields MF(T)ΨΨ-bar in the action and analyze four distinct tachyonic functions F(T) that lead to four different structures of the respective fermionic mass spectra with different physics. In particular, localization of the massless left-chiral fermion zero mode is possible for three of these cases. We further analyze the phenomenology of these Yukawa interactions among fermion fields and gauge bosons localized on the brane and obtain the crucial and necessary information to compute the corrections to Coulomb’s law coming from massive KK vector modes in the non-relativistic limit. These corrections are exponentially suppressed due to the presence of the mass gap in the mass spectrum of the bulk gauge vector field. From our results we conclude that corrections to Coulomb’s law in the thin brane limit have the same form (up to a numerical factor) as far as the left-chiral massless fermion field is localized on the brane. Finally we compute the corrections to the Coulomb’s law for an arbitrarily thick brane scenario which can be interpreted as 5D corrections to the photon mass. By performing consistent estimations with brane phenomenology, we found that the predicted corrections to the photon mass, which are well bounded by the experimentally observed or astrophysically inferred photon mass, are far beyond its upper bound, positively testing the viability of our tachyonic braneworld. Moreover, the 5D parameters that define these corrections possess the same order, providing naturalness to our model, however, a fine-tuning between them is needed in order to fit the corresponding upper bound on the photon mass.« less

Structure-function relations of heparin-mimetic sulfated xylan oligosaccharides: inhibition of human immunodeficiency virus-1 infectivity in vitro.

PubMed

Stone, A L; Melton, D J; Lewis, M S

1998-07-01

Heparins/heparan sulfates modulate the function of proteins and cell membranes in numerous biological systems including normal and disease processes in humans. Heparin has been used for many years as an anticoagulant, and anticoagulant heparin-mimetics were developed several decades ago by chemical sulfation of non-mammalian polysaccharides, e.g., an antithrombotic sulfated xylan. This pharmaceutical, which comprises a mixture of sulfated oligoxylans, also mimics most other biological actions of natural heparins in vitro, including inhibition of the human immunodeficiency virus, but the molecular basis for these actions has been unclear. Here, numerous Components of the sulfated oligoxylan mixture were isolated and when bioassayed in the case of anti-HIV-1 infectivity revealed that a structural specificity underlines the capacity of sulfated xylan to inhibit HIV-1, rather than a non-specific mechanism. Components were isolated by chromatographic fractionation through Bio-Gel P10 in 0.5 M ammonium bicarbonate. This fractionation revealed an elution range associated with apparent molecular weights of approximately 22000 to <1500 relative to standard heparin and heparan sulfates and newly prepared sulfated oligosaccharide standards. Components were characterized by metachromatic absorption spectroscopy, ultracentrifugation, GlcA analysis, and potency against HIV-1 infectivity, both in the tetrazolium cytotoxicity assay and in syncytium-forming assays, in CD4-lymphocytes. Structural specificity was indicated by the differential potencies exhibited by the Components: Highest activity (cytotoxicity) was exhibited by Components in the chromatographic region > or = approximately 5500 in mass (50% effective (inhibitory) concentration = 0.5-0.7 microg ml(-1) in the first fractionation series, and 0.1-0.5 microg ml(-1) in a second series). The potency declined sharply below approximately 5400 in mass, but with an exception; a second structure exhibiting relatively high potency eluted among low-mass oligosaccharides which had an average size of approximately a nonomer. Components displayed differential potencies also against the syncytium-forming infectivity of HIV-1. The high potency against syncytium-formation was retained by Components down to a minimum size of about 4500 in mass, smaller than the > or = approximately 5400 required above. One in ten of the beta1,4-linked xyloses in the native xylan are substituted with a monomeric alpha1,2 DGlcA branch. We have speculated that pharmaceutical actions of sulfated xylan might be related to structures involving the alpha-D linked substituents and this was examined using a space-filling model of a sulfated octaxylan and by analyses of Components for GlcA content. Understanding structure/function relations in the heparin-like actions of these agents would be of general significance for the careful examination of their potential clinical usefulness in many human processes modulated by heparins, including AIDS.

Dynamics of underwater legged locomotion: modeling and experiments on an octopus-inspired robot.

PubMed

Calisti, M; Corucci, F; Arienti, A; Laschi, C

2015-07-30

This paper studies underwater legged locomotion (ULL) by means of a robotic octopus-inspired prototype and its associated model. Two different types of propulsive actions are embedded into the robot model: reaction forces due to leg contact with the ground and hydrodynamic forces such as the drag arising from the sculling motion of the legs. Dynamic parameters of the model are estimated by means of evolutionary techniques and subsequently the model is exploited to highlight some distinctive features of ULL. Specifically, the separation between the center of buoyancy (CoB)/center of mass and density affect the stability and speed of the robot, whereas the sculling movements contribute to propelling the robot even when its legs are detached from the ground. The relevance of these effects is demonstrated through robotic experiments and model simulations; moreover, by slightly changing the position of the CoB in the presence of the same feed-forward activation, a number of different behaviors (i.e. forward and backward locomotion at different speeds) are achieved.

A Systems Model of Parkinson's Disease Using Biochemical Systems Theory.

PubMed

Sasidharakurup, Hemalatha; Melethadathil, Nidheesh; Nair, Bipin; Diwakar, Shyam

2017-08-01

Parkinson's disease (PD), a neurodegenerative disorder, affects millions of people and has gained attention because of its clinical roles affecting behaviors related to motor and nonmotor symptoms. Although studies on PD from various aspects are becoming popular, few rely on predictive systems modeling approaches. Using Biochemical Systems Theory (BST), this article attempts to model and characterize dopaminergic cell death and understand pathophysiology of progression of PD. PD pathways were modeled using stochastic differential equations incorporating law of mass action, and initial concentrations for the modeled proteins were obtained from literature. Simulations suggest that dopamine levels were reduced significantly due to an increase in dopaminergic quinones and 3,4-dihydroxyphenylacetaldehyde (DOPAL) relating to imbalances compared to control during PD progression. Associating to clinically observed PD-related cell death, simulations show abnormal parkin and reactive oxygen species levels with an increase in neurofibrillary tangles. While relating molecular mechanistic roles, the BST modeling helps predicting dopaminergic cell death processes involved in the progression of PD and provides a predictive understanding of neuronal dysfunction for translational neuroscience.

Importance of eccentric actions in performance adaptations to resistance training

NASA Technical Reports Server (NTRS)

Dudley, Gary A.; Miller, Bruce J.; Buchanan, Paul; Tesch, Per A.

1991-01-01

The importance of eccentric (ecc) muscle actions in resistance training for the maintenance of muscle strength and mass in hypogravity was investigated in experiments in which human subjects, divided into three groups, were asked to perform four-five sets of 6 to 12 repetitions (rep) per set of three leg press and leg extension exercises, 2 days each weeks for 19 weeks. One group, labeled 'con', performed each rep with only concentric (con) actions, while group con/ecc with performed each rep with only ecc actions; the third group, con/con, performed twice as many sets with only con actions. Control subjects did not train. It was found that resistance training wih both con and ecc actions induced greater increases in muscle strength than did training with only con actions.

Physical stress, mass, and energy for non-relativistic matter

NASA Astrophysics Data System (ADS)

Geracie, Michael; Prabhu, Kartik; Roberts, Matthew M.

2017-06-01

For theories of relativistic matter fields there exist two possible definitions of the stress-energy tensor, one defined by a variation of the action with the coframes at fixed connection, and the other at fixed torsion. These two stress-energy tensors do not necessarily coincide and it is the latter that corresponds to the Cauchy stress measured in the lab. In this note we discuss the corresponding issue for non-relativistic matter theories. We point out that while the physical non-relativistic stress, momentum, and mass currents are defined by a variation of the action at fixed torsion, the energy current does not admit such a description and is naturally defined at fixed connection. Any attempt to define an energy current at fixed torsion results in an ambiguity which cannot be resolved from the background spacetime data or conservation laws. We also provide computations of these quantities for some simple non-relativistic actions.

Flavor symmetry breaking in lattice QCD with a mixed action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, Oliver; Golterman, Maarten; Shamir, Yigal

2011-03-01

We study the phase structure of mixed-action QCD with two Wilson sea quarks and any number of chiral valence quarks (and ghosts), starting from the chiral Lagrangian. A priori the effective theory allows for a rich phase structure, including a phase with a condensate made of sea and valence quarks. In such a phase, mass eigenstates would become admixtures of sea and valence fields, and pure-sea correlation functions would depend on the parameters of the valence sector, in contradiction with the actual setup of mixed-action simulations. Using that the spectrum of the chiral Dirac operator has a gap for nonzeromore » quark mass we prove that spontaneous symmetry breaking of the flavor symmetries can only occur within the sea sector. This rules out a mixed condensate and implies restrictions on the low-energy constants of the effective theory.« less

Nationalism and Media Coverage of Indigenous People's Collective Action in Canada

ERIC Educational Resources Information Center

Wilkes, Rima; Corrigall-Brown, Catherine; Ricard, Danielle

2010-01-01

Over the past several decades indigenous people in Canada have mounted hundreds of collective action events such as marches, demonstrations, road blockades, and land occupations. What the general public knows about these events and their causes overwhelmingly comes from the mainstream mass media. For this reason, media coverage of these events…

Habits, action sequences, and reinforcement learning

PubMed Central

Dezfouli, Amir; Balleine, Bernard W.

2012-01-01

It is now widely accepted that instrumental actions can be either goal-directed or habitual; whereas the former are rapidly acquire and regulated by their outcome, the latter are reflexive, elicited by antecedent stimuli rather than their consequences. Model-based reinforcement learning (RL) provides an elegant description of goal-directed action. Through exposure to states, actions and rewards, the agent rapidly constructs a model of the world and can choose an appropriate action based on quite abstract changes in environmental and evaluative demands. This model is powerful but has a problem explaining the development of habitual actions. To account for habits, theorists have argued that another action controller is required, called model-free RL, that does not form a model of the world but rather caches action values within states allowing a state to select an action based on its reward history rather than its consequences. Nevertheless, there are persistent problems with important predictions from the model; most notably the failure of model-free RL correctly to predict the insensitivity of habitual actions to changes in the action-reward contingency. Here, we suggest that introducing model-free RL in instrumental conditioning is unnecessary and demonstrate that reconceptualizing habits as action sequences allows model-based RL to be applied to both goal-directed and habitual actions in a manner consistent with what real animals do. This approach has significant implications for the way habits are currently investigated and generates new experimental predictions. PMID:22487034

Heavy-quark meson spectrum tests of the Oktay–Kronfeld action

DOE PAGES

Bailey, Jon A.; DeTar, Carleton; Jang, Yong -Chull; ...

2017-11-15

The Oktay-Kronfeld (OK) action extends the Fermilab improvement program for massive Wilson fermions to higher order in suitable power-counting schemes. It includes dimension-six and -seven operators necessary for matching to QCD through ordermore » $${\\mathrm{O}}(\\Lambda^3/m_Q^3)$$ in HQET power counting, for applications to heavy-light systems, and $${\\mathrm{O}}(v^6)$$ in NRQCD power counting, for applications to quarkonia. In the Symanzik power counting of lattice gauge theory near the continuum limit, the OK action includes all $${\\mathrm{O}}(a^2)$$ and some $${\\mathrm{O}}(a^3)$$ terms. To assess whether the theoretical improvement is realized in practice, we study combinations of heavy-strange and quarkonia masses and mass splittings, designed to isolate heavy-quark discretization effects. We find that, with one exception, the results obtained with the tree-level-matched OK action are significantly closer to the continuum limit than the results obtained with the Fermilab action. The exception is the hyperfine splitting of the bottom-strange system, for which our statistical errors are too large to draw a firm conclusion. Lastly, these studies are carried out with data generated with the tadpole-improved Fermilab and OK actions on 500 gauge configurations from one of MILC's $$a\\approx0.12$$~fm, $$N_f=2+1$$-flavor, asqtad-staggered ensembles.« less

Heavy-quark meson spectrum tests of the Oktay–Kronfeld action

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, Jon A.; DeTar, Carleton; Jang, Yong -Chull

The Oktay-Kronfeld (OK) action extends the Fermilab improvement program for massive Wilson fermions to higher order in suitable power-counting schemes. It includes dimension-six and -seven operators necessary for matching to QCD through ordermore » $${\\mathrm{O}}(\\Lambda^3/m_Q^3)$$ in HQET power counting, for applications to heavy-light systems, and $${\\mathrm{O}}(v^6)$$ in NRQCD power counting, for applications to quarkonia. In the Symanzik power counting of lattice gauge theory near the continuum limit, the OK action includes all $${\\mathrm{O}}(a^2)$$ and some $${\\mathrm{O}}(a^3)$$ terms. To assess whether the theoretical improvement is realized in practice, we study combinations of heavy-strange and quarkonia masses and mass splittings, designed to isolate heavy-quark discretization effects. We find that, with one exception, the results obtained with the tree-level-matched OK action are significantly closer to the continuum limit than the results obtained with the Fermilab action. The exception is the hyperfine splitting of the bottom-strange system, for which our statistical errors are too large to draw a firm conclusion. Lastly, these studies are carried out with data generated with the tadpole-improved Fermilab and OK actions on 500 gauge configurations from one of MILC's $$a\\approx0.12$$~fm, $$N_f=2+1$$-flavor, asqtad-staggered ensembles.« less

Translation of an Action Learning Collaborative Model Into a Community-Based Intervention to Promote Physical Activity and Healthy Eating.

PubMed

Schifferdecker, Karen E; Adachi-Mejia, Anna M; Butcher, Rebecca L; O'Connor, Sharon; Li, Zhigang; Bazos, Dorothy A

2016-01-01

Action Learning Collaboratives (ALCs), whereby teams apply quality improvement (QI) tools and methods, have successfully improved patient care delivery and outcomes. We adapted and tested the ALC model as a community-based obesity prevention intervention focused on physical activity and healthy eating. The intervention used QI tools (e.g., progress monitoring) and team-based activities and was implemented in three communities through nine monthly meetings. To assess process and outcomes, we used a longitudinal repeated-measures and mixed-methods triangulation approach with a quasi-experimental design including objective measures at three time points. Most of the 97 participants were female (85.4%), White (93.8%), and non-Hispanic/Latino (95.9%). Average age was 52 years; 28.0% had annual household income of $20,000 or less; and mean body mass index was 35. Through mixed-effects models, we found some physical activity outcomes improved. Other outcomes did not significantly change. Although participants favorably viewed the QI tools, components of the QI process such as sharing goals and data on progress in teams and during meetings were limited. Participants' requests for more education or activities around physical activity and healthy eating, rather than progress monitoring and data sharing required for QI activities, challenged ALC model implementation. An ALC model for community-based obesity prevention may be more effective when applied to preexisting teams in community-based organizations. © 2015 Society for Public Health Education.

76 FR 22322 - Medical Devices; Immunology and Microbiology Devices; Classification of Ovarian Adnexal Mass...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-21

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 866 [Docket No. FDA-2010-N-0026] Medical Devices; Immunology and Microbiology Devices; Classification of Ovarian Adnexal Mass Assessment Score Test System; Correction AGENCY: Food and Drug Administration, HHS. ACTION...

An Action Assembly Approach to Predicting Emotional Responses to Frightening Mass Media.

ERIC Educational Resources Information Center

Sparks, Glenn G.

1986-01-01

Assesses the validity of a 20-item scale that purportedly measures long term memory records--in this case, frightening mass media. Evidence for validity emerged in that subjects' scale scores were related to negative emotion, negative cognitions, and skin conductance during film clips of scary movies. (NKA)

Embodied Choice: How Action Influences Perceptual Decision Making

PubMed Central

Lepora, Nathan F.; Pezzulo, Giovanni

2015-01-01

Embodied Choice considers action performance as a proper part of the decision making process rather than merely as a means to report the decision. The central statement of embodied choice is the existence of bidirectional influences between action and decisions. This implies that for a decision expressed by an action, the action dynamics and its constraints (e.g. current trajectory and kinematics) influence the decision making process. Here we use a perceptual decision making task to compare three types of model: a serial decision-then-action model, a parallel decision-and-action model, and an embodied choice model where the action feeds back into the decision making. The embodied model incorporates two key mechanisms that together are lacking in the other models: action preparation and commitment. First, action preparation strategies alleviate delays in enacting a choice but also modify decision termination. Second, action dynamics change the prospects and create a commitment effect to the initially preferred choice. Our results show that these two mechanisms make embodied choice models better suited to combine decision and action appropriately to achieve suitably fast and accurate responses, as usually required in ecologically valid situations. Moreover, embodied choice models with these mechanisms give a better account of trajectory tracking experiments during decision making. In conclusion, the embodied choice framework offers a combined theory of decision and action that gives a clear case that embodied phenomena such as the dynamics of actions can have a causal influence on central cognition. PMID:25849349

Embodied choice: how action influences perceptual decision making.

PubMed

Lepora, Nathan F; Pezzulo, Giovanni

2015-04-01

Embodied Choice considers action performance as a proper part of the decision making process rather than merely as a means to report the decision. The central statement of embodied choice is the existence of bidirectional influences between action and decisions. This implies that for a decision expressed by an action, the action dynamics and its constraints (e.g. current trajectory and kinematics) influence the decision making process. Here we use a perceptual decision making task to compare three types of model: a serial decision-then-action model, a parallel decision-and-action model, and an embodied choice model where the action feeds back into the decision making. The embodied model incorporates two key mechanisms that together are lacking in the other models: action preparation and commitment. First, action preparation strategies alleviate delays in enacting a choice but also modify decision termination. Second, action dynamics change the prospects and create a commitment effect to the initially preferred choice. Our results show that these two mechanisms make embodied choice models better suited to combine decision and action appropriately to achieve suitably fast and accurate responses, as usually required in ecologically valid situations. Moreover, embodied choice models with these mechanisms give a better account of trajectory tracking experiments during decision making. In conclusion, the embodied choice framework offers a combined theory of decision and action that gives a clear case that embodied phenomena such as the dynamics of actions can have a causal influence on central cognition.

Predicting herbicide mixture effects on multiple algal species using mixture toxicity models.

PubMed

Nagai, Takashi

2017-10-01

The validity of the application of mixture toxicity models, concentration addition and independent action, to a species sensitivity distribution (SSD) for calculation of a multisubstance potentially affected fraction was examined in laboratory experiments. Toxicity assays of herbicide mixtures using 5 species of periphytic algae were conducted. Two mixture experiments were designed: a mixture of 5 herbicides with similar modes of action and a mixture of 5 herbicides with dissimilar modes of action, corresponding to the assumptions of the concentration addition and independent action models, respectively. Experimentally obtained mixture effects on 5 algal species were converted to the fraction of affected (>50% effect on growth rate) species. The predictive ability of the concentration addition and independent action models with direct application to SSD depended on the mode of action of chemicals. That is, prediction was better for the concentration addition model than the independent action model for the mixture of herbicides with similar modes of action. In contrast, prediction was better for the independent action model than the concentration addition model for the mixture of herbicides with dissimilar modes of action. Thus, the concentration addition and independent action models could be applied to SSD in the same manner as for a single-species effect. The present study to validate the application of the concentration addition and independent action models to SSD supports the usefulness of the multisubstance potentially affected fraction as the index of ecological risk. Environ Toxicol Chem 2017;36:2624-2630. © 2017 SETAC. © 2017 SETAC.

Integrative Analyses of miRNA-mRNA Interactions Reveal let-7b, miR-128 and MAPK Pathway Involvement in Muscle Mass Loss in Sex-Linked Dwarf Chickens

PubMed Central

Luo, Wen; Lin, Shumao; Li, Guihuan; Nie, Qinghua; Zhang, Xiquan

2016-01-01

The sex-linked dwarf (SLD) chicken is an ideal model system for understanding growth hormone (GH)-action and growth hormone receptor (GHR) function because of its recessive mutation in the GHR gene. Skeletal muscle mass is reduced in the SLD chicken with a smaller muscle fiber diameter. Our previous study has presented the mRNA and miRNA expression profiles of the SLD chicken and normal chicken between embryo day 14 and seven weeks of age. However, the molecular mechanism of GHR-deficient induced muscle mass loss is still unclear, and the key molecules and pathways underlying the GHR-deficient induced muscle mass loss also remain to be illustrated. Here, by functional network analysis of the differentially expressed miRNAs and mRNAs between the SLD and normal chickens, we revealed that let-7b, miR-128 and the MAPK pathway might play key roles in the GHR-deficient induced muscle mass loss, and that the reduced cell division and growth are potential cellular processes during the SLD chicken skeletal muscle development. Additionally, we also found some genes and miRNAs involved in chicken skeletal muscle development, through the MAPK, PI3K-Akt, Wnt and Insulin signaling pathways. This study provides new insights into the molecular mechanism underlying muscle mass loss in the SLD chickens, and some regulatory networks that are crucial for chicken skeletal muscle development. PMID:26927061

Community violence, children's development, and mass media: in pursuit of new insights, new goals, and new strategies.

PubMed

Friedlander, B Z

1993-02-01

Community violence that victimizes children is an unmitigated evil that is exacerbated by vast economic and social forces that leave people in central cities and the rural countryside adrift on seas of rolelessness, hopelessness, group disintegration, and alienation. The contemporary drug scene and the easy availability of guns greatly intensify violence on a local scale, while crimes of violence, especially with guns, appear to be level or declining in the nation as a whole. Claims that the persistently high levels of violence in mass media, mostly television, are largely responsible for violence in society represent narrow views of very large issues. These narrow views overlook essential elements of both phenomena--violence and media. Direct models of interpersonal violence in families and in the community probably give rise to more violent behavior than indirect models in media. Disinhibitory and provocative aspects of media probably do as much or more to trigger violent behavior than violent narratives and violent actions. Comprehensive meta-analysis indicates that prosocial messages on television can have greater effects on behavior than antisocial messages. These data support the contention that mass media can play a strong and positive role in alleviating some of the distress of victims of community violence, and in redirecting the behavior of some of its perpetrators so as to protect the children.

The Evolving Contribution of Mass Spectrometry to Integrative Structural Biology

NASA Astrophysics Data System (ADS)

Faini, Marco; Stengel, Florian; Aebersold, Ruedi

2016-06-01

Protein complexes are key catalysts and regulators for the majority of cellular processes. Unveiling their assembly and structure is essential to understanding their function and mechanism of action. Although conventional structural techniques such as X-ray crystallography and NMR have solved the structure of important protein complexes, they cannot consistently deal with dynamic and heterogeneous assemblies, limiting their applications to small scale experiments. A novel methodological paradigm, integrative structural biology, aims at overcoming such limitations by combining complementary data sources into a comprehensive structural model. Recent applications have shown that a range of mass spectrometry (MS) techniques are able to generate interaction and spatial restraints (cross-linking MS) information on native complexes or to study the stoichiometry and connectivity of entire assemblies (native MS) rapidly, reliably, and from small amounts of substrate. Although these techniques by themselves do not solve structures, they do provide invaluable structural information and are thus ideally suited to contribute to integrative modeling efforts. The group of Brian Chait has made seminal contributions in the use of mass spectrometric techniques to study protein complexes. In this perspective, we honor the contributions of the Chait group and discuss concepts and milestones of integrative structural biology. We also review recent examples of integration of structural MS techniques with an emphasis on cross-linking MS. We then speculate on future MS applications that would unravel the dynamic nature of protein complexes upon diverse cellular states.

Melting in super-earths.

PubMed

Stixrude, Lars

2014-04-28

We examine the possible extent of melting in rock-iron super-earths, focusing on those in the habitable zone. We consider the energetics of accretion and core formation, the timescale of cooling and its dependence on viscosity and partial melting, thermal regulation via the temperature dependence of viscosity, and the melting curves of rock and iron components at the ultra-high pressures characteristic of super-earths. We find that the efficiency of kinetic energy deposition during accretion increases with planetary mass; considering the likely role of giant impacts and core formation, we find that super-earths probably complete their accretionary phase in an entirely molten state. Considerations of thermal regulation lead us to propose model temperature profiles of super-earths that are controlled by silicate melting. We estimate melting curves of iron and rock components up to the extreme pressures characteristic of super-earth interiors based on existing experimental and ab initio results and scaling laws. We construct super-earth thermal models by solving the equations of mass conservation and hydrostatic equilibrium, together with equations of state of rock and iron components. We set the potential temperature at the core-mantle boundary and at the surface to the local silicate melting temperature. We find that ancient (∼4 Gyr) super-earths may be partially molten at the top and bottom of their mantles, and that mantle convection is sufficiently vigorous to sustain dynamo action over the whole range of super-earth masses.

Note: Additionally refined new possibilities of plasma probe diagnostics.

PubMed

Riaby, V A; Savinov, V P; Masherov, P E; Yakunin, V G

2018-03-01

In two previous Notes published in this journal, a method of measuring probe sheath thickness and ion mass was described using Langmuir probe diagnostics in low pressure xenon plasma close to Maxwellian substance. According to the first Note, this method includes two stages: (i) in a special experiment with known ion mass, the Bohm and Child-Langmuir-Boguslavsky (CLB) equations for cylindrical Langmuir probes used in this xenon plasma were solved jointly to determine the probe sheath thicknesses and Bohm coefficient C BCyl ≈ 1.13; and (ii) in a general experiment, with known C BCyl , the same equations could be solved to obtain the probe sheath thicknesses and the mean ion mass. In the second Note, the (i) stage of this method was refined: the results of the CLB probe sheath model application, which were termed "evaluations," were corrected using the step-front probe sheath model, which was closer to reality in the special experiment with the xenon plasma. This process resulted in a Bohm coefficient of C BCyl ≈ 1.23 for the cylindrical probe. In the present Note, corrected xenon plasma parameters without the influence of the bare probe protective shield were used for the (i) stage of this diagnostic method. This action also refined the Bohm coefficient, lowering it to C BCyl ≈ 0.745 for cylindrical probes. This advance makes the new diagnostics method more objective and reliable.

Note: Additionally refined new possibilities of plasma probe diagnostics

NASA Astrophysics Data System (ADS)

Riaby, V. A.; Savinov, V. P.; Masherov, P. E.; Yakunin, V. G.

2018-03-01

In two previous Notes published in this journal, a method of measuring probe sheath thickness and ion mass was described using Langmuir probe diagnostics in low pressure xenon plasma close to Maxwellian substance. According to the first Note, this method includes two stages: (i) in a special experiment with known ion mass, the Bohm and Child-Langmuir-Boguslavsky (CLB) equations for cylindrical Langmuir probes used in this xenon plasma were solved jointly to determine the probe sheath thicknesses and Bohm coefficient CBCyl ≈ 1.13; and (ii) in a general experiment, with known CBCyl, the same equations could be solved to obtain the probe sheath thicknesses and the mean ion mass. In the second Note, the (i) stage of this method was refined: the results of the CLB probe sheath model application, which were termed "evaluations," were corrected using the step-front probe sheath model, which was closer to reality in the special experiment with the xenon plasma. This process resulted in a Bohm coefficient of CBCyl ≈ 1.23 for the cylindrical probe. In the present Note, corrected xenon plasma parameters without the influence of the bare probe protective shield were used for the (i) stage of this diagnostic method. This action also refined the Bohm coefficient, lowering it to CBCyl ≈ 0.745 for cylindrical probes. This advance makes the new diagnostics method more objective and reliable.

B*Bπ coupling using relativistic heavy quarks

DOE PAGES

Flynn, J. M.; Fritzsch, P.; Kawanai, T.; ...

2016-01-27

We report on a calculation of the B*Bπ coupling in lattice QCD. The strong matrix element (Bπ|B*) is directly related to the leading order low-energy constant in heavy meson chiral perturbation theory (HM ΧPT) for B mesons. We carry out our calculation directly at the b-quark mass using a non-perturbatively tuned clover action that controls discretization effects of order |p →a| and (ma) n for all n. Our analysis is performed on RBC/UKQCD gauge configurations using domain-wall fermions and the Iwasaki gauge action at two lattice spacings of a –1 = 1.729(25) GeV, a –1 = 2.281 (28) GeV, andmore » unitary pion masses down to 290 MeV. We achieve good statistical precision and control all systematic uncertainties, giving a final result for the HM ΧPT coupling g b = 0.56(3) stat(7) sys in the continuum and at the physical light-quark masses. Furthermore, this is the first calculation performed directly at the physical b-quark mass and lies in the region one would expect from carrying out an interpolation between previous results at the charm mass and at the static point.« less

Measuring pKa of activation and pKi of inactivation for influenza hemagglutinin from kinetics of membrane fusion of virions and of HA expressing cells.

PubMed

Mittal, Aditya; Shangguan, Tong; Bentz, Joe

2002-11-01

The data for the pH dependence of lipid mixing between influenza virus (A/PR/8/34 strain) and fluorescently labeled liposomes containing gangliosides has been analyzed using a comprehensive mass action kinetic model for hemaglutinin (HA)-mediated fusion. Quantitative results obtained about the architecture of HA-mediated membrane fusion site from this analysis are in agreement with the previously reported results from analyses of data for HA-expressing cells fusing with various target membranes. Of the eight or more HAs forming a fusogenic aggregate, only two have to undergo the "essential" conformational change needed to initiate fusion. The mass action kinetic model has been extended to allow the analysis of the pKa for HA activation and pKi for HA inactivation. Inactivation and activation of HA following protonation were investigated for various experimental systems involving different strains of HA (A/PR/8/34, X:31, A/Japan). We find that the pKa for the final protonation site on each monomer of the trimer molecule is 5.6 to 5.7, irrespective of the strain. We also find that the pKi for the PR/8 strain is 4.8 to 4.9. The inactivation rate constants for HA, measured from experiments done with PR/8 virions fusing with liposomes and X:31 HA-expressing cells fusing with red blood cells, were both found to be of the order of 10(-4) s(-1). This number appears to be the minimal rate for HA's essential conformational change at low HA surface density. At high HA surface densities, we find evidence for cooperativity in the conformational change, as suggested by other studies.

Measuring pKa of activation and pKi of inactivation for influenza hemagglutinin from kinetics of membrane fusion of virions and of HA expressing cells.

PubMed Central

Mittal, Aditya; Shangguan, Tong; Bentz, Joe

2002-01-01

The data for the pH dependence of lipid mixing between influenza virus (A/PR/8/34 strain) and fluorescently labeled liposomes containing gangliosides has been analyzed using a comprehensive mass action kinetic model for hemaglutinin (HA)-mediated fusion. Quantitative results obtained about the architecture of HA-mediated membrane fusion site from this analysis are in agreement with the previously reported results from analyses of data for HA-expressing cells fusing with various target membranes. Of the eight or more HAs forming a fusogenic aggregate, only two have to undergo the "essential" conformational change needed to initiate fusion. The mass action kinetic model has been extended to allow the analysis of the pKa for HA activation and pKi for HA inactivation. Inactivation and activation of HA following protonation were investigated for various experimental systems involving different strains of HA (A/PR/8/34, X:31, A/Japan). We find that the pKa for the final protonation site on each monomer of the trimer molecule is 5.6 to 5.7, irrespective of the strain. We also find that the pKi for the PR/8 strain is 4.8 to 4.9. The inactivation rate constants for HA, measured from experiments done with PR/8 virions fusing with liposomes and X:31 HA-expressing cells fusing with red blood cells, were both found to be of the order of 10(-4) s(-1). This number appears to be the minimal rate for HA's essential conformational change at low HA surface density. At high HA surface densities, we find evidence for cooperativity in the conformational change, as suggested by other studies. PMID:12414698

The origin of the mass of the Nambu-Goldstone bosons

NASA Astrophysics Data System (ADS)

Arraut, Ivan

2018-03-01

We explain the origin of the mass for the Nambu-Goldstone bosons when there is a chemical potential in the action which explicitly breaks the symmetry. The method is based on the number of independent histories for the interaction of the pair of Nambu-Goldstone bosons with the degenerate vacuum (triangle relations). The analysis suggests that under some circumstances, pairs of massive Nambu-Goldstone bosons can become a single degree of freedom with an effective mass defined by the superposition of the individual masses of each boson. Possible mass oscillations for the Nambu-Goldstone bosons are discussed.

Interplay between consensus and coherence in a model of interacting opinions

NASA Astrophysics Data System (ADS)

Battiston, Federico; Cairoli, Andrea; Nicosia, Vincenzo; Baule, Adrian; Latora, Vito

2016-06-01

The formation of agents' opinions in a social system is the result of an intricate equilibrium among several driving forces. On the one hand, the social pressure exerted by peers favors the emergence of local consensus. On the other hand, the concurrent participation of agents to discussions on different topics induces each agent to develop a coherent set of opinions across all the topics in which he/she is active. Moreover, the pervasive action of external stimuli, such as mass media, pulls the entire population towards a specific configuration of opinions on different topics. Here we propose a model in which agents with interrelated opinions, interacting on several layers representing different topics, tend to spread their own ideas to their neighborhood, strive to maintain internal coherence, due to the fact that each agent identifies meaningful relationships among its opinions on the different topics, and are at the same time subject to external fields, resembling the pressure of mass media. We show that the presence of heterogeneity in the internal coupling assigned by agents to their different opinions allows to obtain states with mixed levels of consensus, still ensuring that all the agents attain a coherent set of opinions. Furthermore, we show that all the observed features of the model are preserved in the presence of thermal noise up to a critical temperature, after which global consensus is no longer attainable. This suggests the relevance of our results for real social systems, where noise is inevitably present in the form of information uncertainty and misunderstandings. The model also demonstrates how mass media can be effectively used to favor the propagation of a chosen set of opinions, thus polarizing the consensus of an entire population.

Response of the Milky Way's disc to the Large Magellanic Cloud in a first infall scenario

NASA Astrophysics Data System (ADS)

Laporte, Chervin F. P.; Gómez, Facundo A.; Besla, Gurtina; Johnston, Kathryn V.; Garavito-Camargo, Nicolas

2018-01-01

We present N-body and hydrodynamical simulations of the response of the Milky Way's baryonic disc to the presence of the Large Magellanic Cloud during a first infall scenario. For a fiducial Galactic model reproducing the gross properties of the Galaxy, we explore a set of six initial conditions for the Large Magellanic Cloud (LMC) of varying mass which all evolve to fit the measured constraints on its current position and velocity with respect to the Galactic Centre. We find that the LMC can produce strong disturbances - warping of the stellar and gaseous discs - in the Galaxy, without violating constraints from the phase-space distribution of stars in the Solar Neighbourhood. All models correctly reproduce the phases of the warp and its antisymmetrical shape about the disc's mid-plane. If the warp is due to the LMC alone, then the largest mass model is favoured (2.5 × 1011 M⊙). Still, some quantitative discrepancies remain, including deficits in height of ΔZ = 0.7 kpc at R = 22 kpc and ΔZ = 0.7 kpc at R = 16 kpc. This suggests that even higher infall masses for the LMC's halo are allowed by the data. A comparison with the vertical perturbations induced by a heavy Sagittarius dSph model (1011 M⊙) suggest that positive interference with the LMC warp is expected at R = 16 kpc. We conclude that the vertical structure of the Galactic disc beyond the Solar Neighbourhood may jointly be shaped by its most massive satellites. As such, the current structure of the Milky Way suggests we are seeing the process of disc heating by satellite interactions in action.

Rapidly growing Brtl/+ mouse model of osteogenesis imperfecta improves bone mass and strength with sclerostin antibody treatment.

PubMed

Sinder, Benjamin P; Salemi, Joseph D; Ominsky, Michael S; Caird, Michelle S; Marini, Joan C; Kozloff, Kenneth M

2015-02-01

Osteogenesis imperfecta (OI) is a heritable collagen-related bone dysplasia, characterized by brittle bones with increased fracture risk that presents most severely in children. Anti-resorptive bisphosphonates are frequently used to treat pediatric OI and controlled clinical trials have shown that bisphosphonate therapy improves vertebral outcomes but has little benefit on long bone fracture rate. New treatments which increase bone mass throughout the pediatric OI skeleton would be beneficial. Sclerostin antibody (Scl-Ab) is a potential candidate anabolic therapy for pediatric OI and functions by stimulating osteoblastic bone formation via the canonical Wnt signaling pathway. To explore the effect of Scl-Ab on the rapidly growing OI skeleton, we treated rapidly growing 3week old Brtl/+ mice, harboring a typical heterozygous OI-causing Gly→Cys substitution on col1a1, for 5weeks with Scl-Ab. Scl-Ab had anabolic effects in Brtl/+ and led to new cortical bone formation and increased cortical bone mass. This anabolic action resulted in improved mechanical strength to WT Veh levels without altering the underlying brittle nature of the material. While Scl-Ab was anabolic in trabecular bone of the distal femur in both genotypes, the effect was less strong in these rapidly growing Brtl/+ mice compared to WT. In conclusion, Scl-Ab was able to stimulate bone formation in a rapidly growing Brtl/+ murine model of OI, and represents a potential new therapy to improve bone mass and reduce fracture risk in pediatric OI. Copyright © 2014 Elsevier Inc. All rights reserved.

Structural Insights of Glucan Phosphatase Dynamics using Amide Hydrogen/Deuterium Exchange Mass Spectrometry

PubMed Central

Hsu, Simon; Kim, Youngjun; Li, Sheng; Durrant, Eric S.; Pace, Rachel M.; Woods, Virgil L.; Gentry, Matthew S.

2009-01-01

Laforin and Starch Excess 4 (SEX4) are founding members of a class of phosphatases that dephosphorylate phosphoglucans. Each protein contains a carbohydrate binding module (CBM) and a dual specificity phosphatase (DSP) domain. The gene encoding laforin is mutated in a fatal neurodegenerative disease called Lafora disease (LD). In the absence of laforin function, insoluble glucans accumulate that are hyperphosphorylated and exhibit sparse branching. It is hypothesized that these accumulations trigger the neurodegeneration and premature death of LD patients. We recently demonstrated that laforin removes phosphate from phosphoglucans and hypothesized that this function inhibits insoluble glucan accumulation. Loss of SEX4 function in plants yields a similar cellular phenotype; cells accumulate an excess amount of insoluble, hyperphosphorylated glucans. While multiple groups have shown that these phosphatases dephosphorylate phosphoglucans, there is no structure of a glucan phosphatase and little is known about the mechanism whereby they perform this action. We utilized hydrogen-deuterium exchange mass spectrometry (DXMS) and structural modeling to probe the conformational and structural dynamics of the glucan phosphatase SEX4. We found that the enzyme does not undergo a global conformational change upon glucan binding, but instead undergoes minimal rearrangement upon binding. The CBM undergoes increased protection from deuteration when bound to glucans, confirming its role in glucan binding. More interestingly, we identified structural components of the DSP that also undergo increased protection from deuteration upon glucan addition. To determine the position of these regions, we generated a homology model of the SEX4 DSP. The homology model shows that all of these regions are adjacent the DSP active site. Therefore, our results suggest that these regions of the DSP participate in presenting the phosphoglucan to the active site and provide the first structural analysis and mode of action of this unique class of phosphatases. PMID:19754155

Validation of a simple method of estimating plasma free cortisol: role of cortisol binding to albumin.

PubMed

Dorin, Richard I; Pai, Hemanth K; Ho, Jui T; Lewis, John G; Torpy, David J; Urban, Frank K; Qualls, Clifford R

2009-01-01

To develop, optimize, and validate a generalized mass action, equilibrium solution that incorporates measured concentrations of albumin as well as cortisol binding globulin (CBG) to estimate free cortisol. Free cortisol was estimated by Coolens method or by cubic equilibrium equation and compared to measured free cortisol, determined by ultrafiltration method, in subjects with septic shock (n=45), sepsis (n=19), and healthy controls (n=10) at 0, 30, and 60 min following administration of cosyntropin (250 mcg). The data set also included repeat testing in 30 subjects following recovery from sepsis/septic shock. The equilibrium dissociation constant for cortisol binding to albumin (K(A)) was optimized by non-linear regression. The cubic equilibrium solution was also used to model the influence of cortisol, CBG, and albumin concentration on free cortisol. Compared to measured free cortisol, the cubic solution, using an optimized K(A) of 137,800 nM, was less biased than Coolens solution, with mean percent error of -23.0% vs. -41.1% (paired t test, P<0.001). Standard deviation values were also significantly lower (Wilks' test, P<0.001) for the cubic solution (SD 35.8% vs. 40.8% for cubic vs. Coolens, respectively). Modeling studies using the cubic solution suggest an interaction effect by which low concentrations of CBG and albumin contribute to a greater increase in free cortisol than the sum of their independent effects. Mass action solutions that incorporate the measured concentration of albumin as well as CBG provide a reasonably accurate estimate of free cortisol that generalizes to conditions of health as well as a setting of hypercortisolism and low CBG and albumin concentrations associated with septic shock. Modeling studies emphasize the significant contribution of albumin deficiency and albumin-bound cortisol under conditions of CBG-deficiency, and identify a synergistic effect by which combined CBG and albumin deficiency contribute to elevation of free cortisol in septic shock.

Evaluation of the preparation of the coronal part of the mesial canals of lower molars.

PubMed

Sinan, A; Georgelin-Gurgel, M; Diemer, F

2011-03-01

Canal entrances can be flared using specific, low speed, continuously rotating Ni-Ti instruments. Two such instruments were evaluated for their capacity to flare the canal entrance while respecting the initial canal axis. Lower molars (n = 20) with two distinct mesial canals were prepared to within 2.5 mm of the pulp chamber floor using Bramante's technique. Canal entrances were flared with a QUANTEC FLARE LX or an ENDOFLARE. They both had a 0.12 taper and a #25 tip diameter. The instruments were first inserted in the canals using an axial movement and then withdrawn with a selective circumferential brushing action. Photographs taken before and after each preparation were compared. No ledging or significant modification of the working length was noted. The centre of mass was displaced on average by 0.138 mm with no brushing action and 0.274 mm with brushing action. In most cases (87.5%), the centre of mass was displaced mesially. The two instruments behaved in an identical mode, both before (p = 0.3497) and after (p = 0.9304) the brushing action. Ni-Ti flaring instruments can be used to flare the canal entrance with little displacement of the initial canal axis, even when a brushing action is used.

Experimental measurement of binding energy, selectivity, and allostery using fluctuation theorems.

PubMed

Camunas-Soler, Joan; Alemany, Anna; Ritort, Felix

2017-01-27

Thermodynamic bulk measurements of binding reactions rely on the validity of the law of mass action and the assumption of a dilute solution. Yet, important biological systems such as allosteric ligand-receptor binding, macromolecular crowding, or misfolded molecules may not follow these assumptions and may require a particular reaction model. Here we introduce a fluctuation theorem for ligand binding and an experimental approach using single-molecule force spectroscopy to determine binding energies, selectivity, and allostery of nucleic acids and peptides in a model-independent fashion. A similar approach could be used for proteins. This work extends the use of fluctuation theorems beyond unimolecular folding reactions, bridging the thermodynamics of small systems and the basic laws of chemical equilibrium. Copyright © 2017, American Association for the Advancement of Science.

Reconstructing biochemical pathways from time course data.

PubMed

Srividhya, Jeyaraman; Crampin, Edmund J; McSharry, Patrick E; Schnell, Santiago

2007-03-01

Time series data on biochemical reactions reveal transient behavior, away from chemical equilibrium, and contain information on the dynamic interactions among reacting components. However, this information can be difficult to extract using conventional analysis techniques. We present a new method to infer biochemical pathway mechanisms from time course data using a global nonlinear modeling technique to identify the elementary reaction steps which constitute the pathway. The method involves the generation of a complete dictionary of polynomial basis functions based on the law of mass action. Using these basis functions, there are two approaches to model construction, namely the general to specific and the specific to general approach. We demonstrate that our new methodology reconstructs the chemical reaction steps and connectivity of the glycolytic pathway of Lactococcus lactis from time course experimental data.

A BGK model for reactive mixtures of polyatomic gases with continuous internal energy

NASA Astrophysics Data System (ADS)

Bisi, M.; Monaco, R.; Soares, A. J.

2018-03-01

In this paper we derive a BGK relaxation model for a mixture of polyatomic gases with a continuous structure of internal energies. The emphasis of the paper is on the case of a quaternary mixture undergoing a reversible chemical reaction of bimolecular type. For such a mixture we prove an H -theorem and characterize the equilibrium solutions with the related mass action law of chemical kinetics. Further, a Chapman-Enskog asymptotic analysis is performed in view of computing the first-order non-equilibrium corrections to the distribution functions and investigating the transport properties of the reactive mixture. The chemical reaction rate is explicitly derived at the first order and the balance equations for the constituent number densities are derived at the Euler level.

Computational Modeling and Analysis of Insulin Induced Eukaryotic Translation Initiation

PubMed Central

Lequieu, Joshua; Chakrabarti, Anirikh; Nayak, Satyaprakash; Varner, Jeffrey D.

2011-01-01

Insulin, the primary hormone regulating the level of glucose in the bloodstream, modulates a variety of cellular and enzymatic processes in normal and diseased cells. Insulin signals are processed by a complex network of biochemical interactions which ultimately induce gene expression programs or other processes such as translation initiation. Surprisingly, despite the wealth of literature on insulin signaling, the relative importance of the components linking insulin with translation initiation remains unclear. We addressed this question by developing and interrogating a family of mathematical models of insulin induced translation initiation. The insulin network was modeled using mass-action kinetics within an ordinary differential equation (ODE) framework. A family of model parameters was estimated, starting from an initial best fit parameter set, using 24 experimental data sets taken from literature. The residual between model simulations and each of the experimental constraints were simultaneously minimized using multiobjective optimization. Interrogation of the model population, using sensitivity and robustness analysis, identified an insulin-dependent switch that controlled translation initiation. Our analysis suggested that without insulin, a balance between the pro-initiation activity of the GTP-binding protein Rheb and anti-initiation activity of PTEN controlled basal initiation. On the other hand, in the presence of insulin a combination of PI3K and Rheb activity controlled inducible initiation, where PI3K was only critical in the presence of insulin. Other well known regulatory mechanisms governing insulin action, for example IRS-1 negative feedback, modulated the relative importance of PI3K and Rheb but did not fundamentally change the signal flow. PMID:22102801

From fractals to wormholes via string theory

NASA Astrophysics Data System (ADS)

Felce, Andrew George

The thesis is in two parts. The first part is devoted to a study of the definition of mass for soliton solutions in string theory. In the context of the low-energy effective field theory, there are three distinct quantities from which one can extract the mass of a soliton: the ADM mass, the static action and the kinetic energy. The three corresponding masses are carefully defined and shown to be equal for a representative class of string solitons, the so-called 'black fivebranes'. Along the way a potential confusion in the definition of the action is cleared up, and it is shown that the kinetic energy of a moving soliton is given in terms of a surface integral at spacelike infinity. This result for the kinetic energy is used to motivate a conjecture about the exact value of soliton masses in string theory: That in conformal field theory the kinetic mass is realized as the norm of the (1,1) deformation induced by the collective coordinate. Such deformations are usually treated as unphysical because they appear to be pure gauge and have zero norm. In a soliton conformal field theory, a finite number of these gauge transformations become physical because of a subtlety involving the boundary at spatial infinity. Some proposals for concrete exploration of this phenomenon are discussed. The second part of the thesis concerns the connection between string theory and an important problem in condensed matter physics. It has recently been shown that the dissipative Hofstadter model (dissipative quantum mechanics of an electron subject to uniform magnetic field and periodic potential in two dimensions) exhibits critical behavior on a network of lines in the dissipation/magnetic field plane. Apart from their obvious condensed matter interest, the corresponding critical theories represent non-trivial solutions of open string field theory containing a tachyon and gauge field background. A detailed account of their properties would be interesting from several points of view. The thesis reports the results of an initial investigation of the free energy, N-point functions and boundary state for this type of critical theory. Although the primary goal is to study the magnetic field dependence of these quantities, some new results are presented which bear on the zero magnetic field case as well.

Introducing survival ethics into engineering education and practice.

PubMed

Verharen, C; Tharakan, J; Middendorf, G; Castro-Sitiriche, M; Kadoda, G

2013-06-01

Given the possibilities of synthetic biology, weapons of mass destruction and global climate change, humans may achieve the capacity globally to alter life. This crisis calls for an ethics that furnishes effective motives to take global action necessary for survival. We propose a research program for understanding why ethical principles change across time and culture. We also propose provisional motives and methods for reaching global consensus on engineering field ethics. Current interdisciplinary research in ethics, psychology, neuroscience and evolutionary theory grounds these proposals. Experimental ethics, the application of scientific principles to ethical studies, provides a model for developing policies to advance solutions. A growing literature proposes evolutionary explanations for moral development. Connecting these approaches necessitates an experimental or scientific ethics that deliberately examines theories of morality for reliability. To illustrate how such an approach works, we cover three areas. The first section analyzes cross-cultural ethical systems in light of evolutionary theory. While such research is in its early stages, its assumptions entail consequences for engineering education. The second section discusses Howard University and University of Puerto Rico/Mayagüez (UPRM) courses that bring ethicists together with scientists and engineers to unite ethical theory and practice. We include a syllabus for engineering and STEM (Science, Technology, Engineering and Mathematics) ethics courses and a checklist model for translating educational theory and practice into community action. The model is based on aviation, medicine and engineering practice. The third and concluding section illustrates Howard University and UPRM efforts to translate engineering educational theory into community action. Multidisciplinary teams of engineering students and instructors take their expertise from the classroom to global communities to examine further the ethicality of prospective technologies and the decision-making processes that lead to them.

Simulating Chemical Kinetics Without Differential Equations: A Quantitative Theory Based on Chemical Pathways.

PubMed

Bai, Shirong; Skodje, Rex T

2017-08-17

A new approach is presented for simulating the time-evolution of chemically reactive systems. This method provides an alternative to conventional modeling of mass-action kinetics that involves solving differential equations for the species concentrations. The method presented here avoids the need to solve the rate equations by switching to a representation based on chemical pathways. In the Sum Over Histories Representation (or SOHR) method, any time-dependent kinetic observable, such as concentration, is written as a linear combination of probabilities for chemical pathways leading to a desired outcome. In this work, an iterative method is introduced that allows the time-dependent pathway probabilities to be generated from a knowledge of the elementary rate coefficients, thus avoiding the pitfalls involved in solving the differential equations of kinetics. The method is successfully applied to the model Lotka-Volterra system and to a realistic H 2 combustion model.

20 CFR 639.3 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-04-01

..., including part-time employees, who in the aggregate work at least 4,000 hours per week, exclusive of hours... action that results in the effective cessation of production or the work performed by a unit, even if a... work as specified under the definition of “employment loss.” (c) Mass layoff. (1) The term “mass layoff...

Mass Media, Education, and a Better Society.

ERIC Educational Resources Information Center

Stein, Jay W.

In an examination of the conflict between the mass media and public education, the author concludes that a pressing need exists for better understanding and cooperation between the two and calls for action which involves them both. The overcommunication of the media and the under-utilization of the media toward constructive ends are examined.…

The Mass Media of Entertainment and Human Survival.

ERIC Educational Resources Information Center

Gorney, Roderic; Steele, Gary

Urgently needed for human survival is a means of influencing large numbers of people to put into rapid action measures which could neutralize such menances as pollution, overpopulation, and violence. Though the cumulative effect of the mass media is not fully established, media entertainment may be the most influential institution in our society.…

Reopening the Black Box: Toward a Limited Effects Theory.

ERIC Educational Resources Information Center

Gans, Herbert J.

1993-01-01

Discusses eight limiting factors on media effects, identifying and raising research questions about agents and structures that limit the potential effects of the mass media on the behavior and attitudes of people and on the actions of institutions. Discusses the ignorance of researchers about how people use, and live with, the mass media. (SR)

77 FR 71452 - Extension of Comment Period: Orphan Works and Mass Digitization

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-30

... Office hereby extends the time for filing comments to 5:00 p.m. EST on February 4, 2013. The due date for... LIBRARY OF CONGRESS Copyright Office [Docket No. 2012-10] Extension of Comment Period: Orphan Works and Mass Digitization AGENCY: Copyright Office, Library of Congress. ACTION: Extension of comment...

75 FR 28200 - Safety Zone; Washington State Department of Transportation Ferries Division Marine Rescue...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-20

... (M2R) Full-Scale Exercise for a Mass Rescue Incident (MRI) AGENCY: Coast Guard, DHS. ACTION: Temporary... simulate a mass rescue incident (MRI) and will involve an abandon ship scenario with multiple response... full scale exercise which will simulate a MRI to provide training in specific emergency response...

BPS-like bound and thermodynamics of the charged BTZ black hole

NASA Astrophysics Data System (ADS)

Cadoni, Mariano; Monni, Cristina

2009-07-01

The charged Bañados-Teitelboim-Zanelli (BTZ) black hole is plagued by several pathologies: (a) Divergent boundary terms are present in the action; hence, we have a divergent black-hole mass. (b) Once a finite, renormalized, mass M is defined, black-hole states exist for arbitrarily negative values of M. (c) There is no upper bound on the charge Q. We show that these pathological features are an artifact of the renormalization procedure. They can be completely removed by using an alternative renormalization scheme leading to a different definition M0 of the black-hole mass, which is the total energy inside the horizon. The new mass satisfies a BPS-like bound M0≥(π)/(2)Q2, and the heat capacity of the hole is positive. We also discuss the black-hole thermodynamics that arises when M0 is interpreted as the internal energy of the system. We show, using three independent approaches (black-hole thermodynamics, Einstein equations, and Euclidean action formulation), that M0 satisfies the first law if a term describing the mechanical work done by the electrostatic pressure is introduced.

Quarks, Symmetries and Strings - a Symposium in Honor of Bunji Sakita's 60th Birthday

NASA Astrophysics Data System (ADS)

Kaku, M.; Jevicki, A.; Kikkawa, K.

1991-04-01

The Table of Contents for the full book PDF is as follows: * Preface * Evening Banquet Speech * I. Quarks and Phenomenology * From the SU(6) Model to Uniqueness in the Standard Model * A Model for Higgs Mechanism in the Standard Model * Quark Mass Generation in QCD * Neutrino Masses in the Standard Model * Solar Neutrino Puzzle, Horizontal Symmetry of Electroweak Interactions and Fermion Mass Hierarchies * State of Chiral Symmetry Breaking at High Temperatures * Approximate |ΔI| = 1/2 Rule from a Perspective of Light-Cone Frame Physics * Positronium (and Some Other Systems) in a Strong Magnetic Field * Bosonic Technicolor and the Flavor Problem * II. Strings * Supersymmetry in String Theory * Collective Field Theory and Schwinger-Dyson Equations in Matrix Models * Non-Perturbative String Theory * The Structure of Non-Perturbative Quantum Gravity in One and Two Dimensions * Noncritical Virasoro Algebra of d < 1 Matrix Model and Quantized String Field * Chaos in Matrix Models ? * On the Non-Commutative Symmetry of Quantum Gravity in Two Dimensions * Matrix Model Formulation of String Field Theory in One Dimension * Geometry of the N = 2 String Theory * Modular Invariance form Gauge Invariance in the Non-Polynomial String Field Theory * Stringy Symmetry and Off-Shell Ward Identities * q-Virasoro Algebra and q-Strings * Self-Tuning Fields and Resonant Correlations in 2d-Gravity * III. Field Theory Methods * Linear Momentum and Angular Momentum in Quaternionic Quantum Mechanics * Some Comments on Real Clifford Algebras * On the Quantum Group p-adics Connection * Gravitational Instantons Revisited * A Generalized BBGKY Hierarchy from the Classical Path-Integral * A Quantum Generated Symmetry: Group-Level Duality in Conformal and Topological Field Theory * Gauge Symmetries in Extended Objects * Hidden BRST Symmetry and Collective Coordinates * Towards Stochastically Quantizing Topological Actions * IV. Statistical Methods * A Brief Summary of the s-Channel Theory of Superconductivity * Neural Networks and Models for the Brain * Relativistic One-Body Equations for Planar Particles with Arbitrary Spin * Chiral Property of Quarks and Hadron Spectrum in Lattice QCD * Scalar Lattice QCD * Semi-Superconductivity of a Charged Anyon Gas * Two-Fermion Theory of Strongly Correlated Electrons and Charge-Spin Separation * Statistical Mechanics and Error-Correcting Codes * Quantum Statistics

Musculoskeletal Modeling of the Lumbar Spine to Explore Functional Interactions between Back Muscle Loads and Intervertebral Disk Multiphysics

PubMed Central

Toumanidou, Themis; Noailly, Jérôme

2015-01-01

During daily activities, complex biomechanical interactions influence the biophysical regulation of intervertebral disks (IVDs), and transfers of mechanical loads are largely controlled by the stabilizing action of spine muscles. Muscle and other internal forces cannot be easily measured directly in the lumbar spine. Hence, biomechanical models are important tools for the evaluation of the loads in those tissues involved in low-back disorders. Muscle force estimations in most musculoskeletal models mainly rely, however, on inverse calculations and static optimizations that limit the predictive power of the numerical calculations. In order to contribute to the development of predictive systems, we coupled a predictive muscle model with the passive resistance of the spine tissues, in a L3–S1 musculoskeletal finite element model with osmo-poromechanical IVD descriptions. The model included 46 fascicles of the major back muscles that act on the lower spine. The muscle model interacted with activity-related loads imposed to the osteoligamentous structure, as standing position and night rest were simulated through distributed upper body mass and free IVD swelling, respectively. Calculations led to intradiscal pressure values within ranges of values measured in vivo. Disk swelling led to muscle activation and muscle force distributions that seemed particularly appropriate to counterbalance the anterior body mass effect in standing. Our simulations pointed out a likely existence of a functional balance between stretch-induced muscle activation and IVD multiphysics toward improved mechanical stability of the lumbar spine understanding. This balance suggests that proper night rest contributes to mechanically strengthen the spine during day activity. PMID:26301218

The Effects of Fortetropin Supplementation on Body Composition, Strength, and Power in Humans and Mechanism of Action in a Rodent Model.

PubMed

Sharp, Matthew H; Lowery, Ryan P; Mobley, C Brooks; Fox, Carlton D; de Souza, Eduardo O; Shields, Kevin A; Healy, James C; Arick, Ned Q; Thompson, Richard M; Roberts, Michael D; Wilson, Jacob M

2016-01-01

The purpose of this study was to investigate the effects of Fortetropin on skeletal muscle growth and strength in resistance-trained individuals and to investigate the anabolic and catabolic signaling effects using human and rodent models. In the rodent model, male Wistar rats (250 g) were gavage fed with either 1.2 ml of tap water control (CTL) or 0.26 g Fortetropin for 8 days. Then rats participated in a unilateral plantarflexion exercise bout. Nonexercised and exercised limbs were harvested at 180 minutes following and analyzed for gene and protein expression relative to mammalian target of rapamycin (mTOR) and ubiquitin signaling. For the human model, 45 (of whom 37 completed the study), resistance-trained college-aged males were divided equally into 3 groups receiving a placebo macronutrient matched control, 6.6 or 19.8 g of Fortetropin supplementation during 12 weeks of resistance training. Lean mass, muscle thickness, and lower and upper body strength were measured before and after 12 weeks of training. The human study results indicated a Group × Time effect (p ≤ 0.05) for lean mass in which the 6.6 g (+1.7 kg) and 19.8 g (+1.68 kg) but not placebo (+0.6 kg) groups increased lean mass. Similarly, there was a Group × Time effect for muscle thickness (p ≤ 0.05), which increased in the experimental groups only. All groups increased equally in bench press and leg press strength. In the rodent model, a main effect for exercise (p ≤ 0.05) in which the control plus exercise but not Fortetropin plus exercise increased both ubiquitin monomer protein expression and polyubiquitination. mTOR signaling was elevated to a greater extent in the Fortetropin exercising conditions as indicated by greater phosphorylation status of 4EBP1, rp6, and p70S6K for both exercising conditions. Fortetropin supplementation increases lean body mass (LBM) and decreases markers of protein breakdown while simultaneously increasing mTOR signaling.

Regge spectra of excited mesons, harmonic confinement, and QCD vacuum structure

NASA Astrophysics Data System (ADS)

Nedelko, Sergei N.; Voronin, Vladimir E.

2016-05-01

An approach to QCD vacuum as a medium describable in terms of a statistical ensemble of almost everywhere homogeneous Abelian (anti-)self-dual gluon fields is briefly reviewed. These fields play the role of the confining medium for color charged fields as well as underline the mechanism of realization of chiral S UL(Nf)×S UR(Nf) and UA(1 ) symmetries. Hadronization formalism based on this ensemble leads to manifestly defined quantum effective meson action. Strong, electromagnetic, and weak interactions of mesons are represented in the action in terms of nonlocal n -point interaction vertices given by the quark-gluon loops averaged over the background ensemble. New systematic results for the mass spectrum and decay constants of radially excited light, heavy-light mesons, and heavy quarkonia are presented. The interrelation between the present approach, models based on ideas of soft-wall anti-de Sitter/QCD, light-front holographic QCD, and the picture of harmonic confinement is outlined.

The mechanism and theoretical basis of the management of intensity of the heat transfer control through periodic influences on the turbulent boundary layer

NASA Astrophysics Data System (ADS)

Kovalnogov, Vladislav N.; Fedorov, Ruslan V.; Khakhaleva, Larisa V.; Chukalin, Andrey V.; Bondarenko, Aleksandr A.; Kovrizhnykh, Evgeny N.

2017-07-01

Generalization of classical model of a displacement way on the transfer of heat exchange and mass exchange of a stream in the boundary layer, confirmed by the control action of the different nature, is undertaken. Here are given the results of numerical research which have allowed explaining the mechanism, to reveal efficiency and limits of various ways of management of intensity in exchange processes. The possibility of management of intensity in processes of a thermolysis and friction by use of the perforated surface with the damping cavities is analyzed.

Generation of dynamo magnetic fields in the primordial solar nebula

NASA Technical Reports Server (NTRS)

Stepinski, Tomasz F.

1992-01-01

The present treatment of dynamo-generated magnetic fields in the primordial solar nebula proceeds in view of the ability of the combined action of Keplerian rotation and helical convention to generate, via alpha-omega dynamo, large-scale magnetic fields in those parts of the nebula with sufficiently high, gas-and magnetic field coupling electrical conductivity. Nebular gas electrical conductivity and the radial distribution of the local dynamo number are calculated for both a viscous-accretion disk model and the quiescent-minimum mass nebula. It is found that magnetic fields can be easily generated and maintained by alpha-omega dynamos occupying the inner and outer parts of the nebula.

Finite temperature corrections and embedded strings in noncommutative geometry and the standard model with neutrino mixing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martins, R. A.

The recent extension of the standard model to include massive neutrinos in the framework of noncommutative geometry and the spectral action principle involves new scalar fields and their interactions with the usual complex scalar doublet. After ensuring that they bring no unphysical consequences, we address the question of how these fields affect the physics predicted in the Weinberg-Salam theory, particularly in the context of the electroweak phase transition. Applying the Dolan-Jackiw procedure, we calculate the finite temperature corrections, and find that the phase transition is first order. The new scalar interactions significantly improve the stability of the electroweak Z string,more » through the 'bag' phenomenon described by Vachaspati and Watkins ['Bound states can stabilize electroweak strings', Phys. Lett. B 318, 163-168 (1993)]. (Recently, cosmic strings have climbed back into interest due to a new evidence.) Sourced by static embedded strings, an internal space analogy of Cartan's torsion is drawn, and a possible Higgs-force-like 'gravitational' effect of this nonpropagating torsion on the fermion masses is described. We also check that the field generating the Majorana mass for the {nu}{sub R} is nonzero in the physical vacuum.« less

Solid/liquid extraction equilibria of phenolic compounds with trioctylphosphine oxide impregnated in polymeric membranes.

PubMed

Praveen, Prashant; Loh, Kai-Chee

2016-06-01

Trioctylphosphine oxide based extractant impregnated membranes (EIM) were used for extraction of phenol and its methyl, hydroxyl and chloride substituted derivatives. The distribution coefficients of the phenols varied from 2 to 234, in the order of 1-napthol > p-chlorophenol > m-cresol > p-cresol > o-cresol > phenol > catechol > pyrogallol > hydroquinone, when initial phenols loadings was varied in 100-2000 mg/L. An extraction model, based on the law of mass action, was formulated to predict the equilibrium distribution of the phenols. The model was in excellent agreement (R(2) > 0.97) with the experimental results at low phenols concentrations (<800 mg/L). At higher phenols loadings though, Langmuir isotherm was better suited for equilibrium prediction (R(2) > 0.95), which signified high mass transfer resistance in the EIMs. Examination of the effects of ring substitution on equilibrium, and bivariate statistical analysis between the amounts of phenols extracted into the EIMs and factors affecting phenols interaction with TOPO, indicated the dominant role of hydrophobicity in equilibrium determination. These results improve understanding of the solid/liquid equilibrium process between phenols and the EIMs, and these will be useful in designing phenol recovery process from wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Guidelines for Mass Casualty Decontamination During a HAZMAT/Weapon of Mass Destruction Incident. Volumes 1 and 2 (Update)

DTIC Science & Technology

2013-08-01

neutralization: 1. Physical removal involves mechanical action with techniques such as gentle fric- tion (such as rubbing with hands, soft non...sulfur mustard), using gen- tle friction, such as rubbing with hands, a soft cloth, or sponges is recommended to aid in re- moval of the contaminants...account for both initial mass decontamination and secondary de- contamination. Some examples include the use of colored rubber bands and specially de

Intentions to Perform Non-Pharmaceutical Protective Behaviors during Influenza Outbreaks in Sweden: A Cross-Sectional Study following a Mass Vaccination Campaign

PubMed Central

Timpka, Toomas; Spreco, Armin; Gursky, Elin; Eriksson, Olle; Dahlström, Örjan; Strömgren, Magnus; Ekberg, Joakim; Pilemalm, Sofie; Karlsson, David; Hinkula, Jorma; Holm, Einar

2014-01-01

Failure to incorporate the beliefs and attitudes of the public into theoretical models of preparedness has been identified as a weakness in strategies to mitigate infectious disease outbreaks. We administered a cross-sectional telephone survey to a representative sample (n = 443) of the Swedish adult population to examine whether self-reported intentions to improve personal hygiene and increase social distancing during influenza outbreaks could be explained by trust in official information, self-reported health (SF-8), sociodemographic factors, and determinants postulated in protection motivation theory, namely threat appraisal and coping appraisal. The interviewees were asked to make their appraisals for two scenarios: a) an influenza with low case fatality and mild lifestyle impact; b) severe influenza with high case fatality and serious disturbances of societal functions. Every second respondent (50.0%) reported high trust in official information about influenza. The proportion that reported intentions to take deliberate actions to improve personal hygiene during outbreaks ranged between 45–85%, while less than 25% said that they intended to increase social distancing. Multiple logistic regression models with coping appraisal as the explanatory factor most frequently contributing to the explanation of the variance in intentions showed strong discriminatory performance for staying home while not ill (mild outbreaks: Area under the curve [AUC] 0.85 (95% confidence interval 0.82;0.89), severe outbreaks AUC 0.82 (95% CI 0.77;0.85)) and acceptable performance with regard to avoiding public transportation (AUC 0.78 (0.74;0.82), AUC 0.77 (0.72;0.82)), using handwash products (AUC 0.70 (0.65;0.75), AUC 0.76 (0.71;0.80)), and frequently washing hands (AUC 0.71 (0.66;0.76), AUC 0.75 (0.71;0.80)). We conclude that coping appraisal was the explanatory factor most frequently included in statistical models explaining self-reported intentions to carry out non-pharmaceutical health actions in the Swedish outlined context, and that variations in threat appraisal played a smaller role in these models despite scientific uncertainties surrounding a recent mass vaccination campaign. PMID:24608557

Intentions to perform non-pharmaceutical protective behaviors during influenza outbreaks in Sweden: a cross-sectional study following a mass vaccination campaign.

PubMed

Timpka, Toomas; Spreco, Armin; Gursky, Elin; Eriksson, Olle; Dahlström, Örjan; Strömgren, Magnus; Ekberg, Joakim; Pilemalm, Sofie; Karlsson, David; Hinkula, Jorma; Holm, Einar

2014-01-01

Failure to incorporate the beliefs and attitudes of the public into theoretical models of preparedness has been identified as a weakness in strategies to mitigate infectious disease outbreaks. We administered a cross-sectional telephone survey to a representative sample (n = 443) of the Swedish adult population to examine whether self-reported intentions to improve personal hygiene and increase social distancing during influenza outbreaks could be explained by trust in official information, self-reported health (SF-8), sociodemographic factors, and determinants postulated in protection motivation theory, namely threat appraisal and coping appraisal. The interviewees were asked to make their appraisals for two scenarios: a) an influenza with low case fatality and mild lifestyle impact; b) severe influenza with high case fatality and serious disturbances of societal functions. Every second respondent (50.0%) reported high trust in official information about influenza. The proportion that reported intentions to take deliberate actions to improve personal hygiene during outbreaks ranged between 45-85%, while less than 25% said that they intended to increase social distancing. Multiple logistic regression models with coping appraisal as the explanatory factor most frequently contributing to the explanation of the variance in intentions showed strong discriminatory performance for staying home while not ill (mild outbreaks: Area under the curve [AUC] 0.85 (95% confidence interval 0.82;0.89), severe outbreaks AUC 0.82 (95% CI 0.77;0.85)) and acceptable performance with regard to avoiding public transportation (AUC 0.78 (0.74;0.82), AUC 0.77 (0.72;0.82)), using handwash products (AUC 0.70 (0.65;0.75), AUC 0.76 (0.71;0.80)), and frequently washing hands (AUC 0.71 (0.66;0.76), AUC 0.75 (0.71;0.80)). We conclude that coping appraisal was the explanatory factor most frequently included in statistical models explaining self-reported intentions to carry out non-pharmaceutical health actions in the Swedish outlined context, and that variations in threat appraisal played a smaller role in these models despite scientific uncertainties surrounding a recent mass vaccination campaign.

Vacuum statistics and stability in axionic landscapes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Masoumi, Ali; Vilenkin, Alexander, E-mail: ali@cosmos.phy.tufts.edu, E-mail: vilenkin@cosmos.phy.tufts.edu

2016-03-01

We investigate vacuum statistics and stability in random axionic landscapes. For this purpose we developed an algorithm for a quick evaluation of the tunneling action, which in most cases is accurate within 10%. We find that stability of a vacuum is strongly correlated with its energy density, with lifetime rapidly growing as the energy density is decreased. On the other hand, the probability P(B) for a vacuum to have a tunneling action B greater than a given value declines as a slow power law in B. This is in sharp contrast with the studies of random quartic potentials, which foundmore » a fast exponential decline of P(B). Our results suggest that the total number of relatively stable vacua (say, with B>100) grows exponentially with the number of fields N and can get extremely large for N∼> 100. The problem with this kind of model is that the stable vacua are concentrated near the absolute minimum of the potential, so the observed value of the cosmological constant cannot be explained without fine-tuning. To address this difficulty, we consider a modification of the model, where the axions acquire a quadratic mass term, due to their mixing with 4-form fields. This results in a larger landscape with a much broader distribution of vacuum energies. The number of relatively stable vacua in such models can still be extremely large.« less

Impact of bacterial activity on turnover of insoluble hydrophobic substrates (phenanthrene and pyrene)-Model simulations for prediction of bioremediation success.

PubMed

Rein, Arno; Adam, Iris K U; Miltner, Anja; Brumme, Katja; Kästner, Matthias; Trapp, Stefan

2016-04-05

Many attempts for bioremediation of polycyclic aromatic hydrocarbon (PAH) contaminated sites failed in the past, but the reasons for this failure are not well understood. Here we apply and improve a model for integrated assessment of mass transfer, biodegradation and residual concentrations for predicting the success of remediation actions. First, we provide growth parameters for Mycobacterium rutilum and Mycobacterium pallens growing on phenanthrene (PHE) or pyrene (PYR) degraded the PAH completely at all investigated concentrations. Maximum metabolic rates vmax and growth rates μ were similar for the substrates PHE and PYR and for both strains. The investigated Mycobacterium species were not superior in PHE degradation to strains investigated earlier with this method. Real-world degradation scenario simulations including diffusive flux to the microbial cells indicate: that (i) bioaugmentation only has a small, short-lived effect; (ii) Increasing sorption shifts the remaining PAH to the adsorbed/sequestered PAH pool; (iii) mobilizing by solvents or surfactants resulted in a significant decrease of the sequestered PAH, and (iv) co-metabolization e.g. by compost addition can contribute significantly to the reduction of PAH, because active biomass is maintained at a high level by the compost. The model therefore is a valuable contribution to the assessment of potential remediation action at PAH-polluted sites. Copyright © 2015 Elsevier B.V. All rights reserved.

36 CFR § 1010.7 - Actions that do not require an EA or EIS.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Actions that do not require an EA or EIS. § 1010.7 Section § 1010.7 Parks, Forests, and Public Property PRESIDIO TRUST... utility right-of-way; and (37) Experimental testing of no longer than 180 days of mass transit systems...

Lattice gauge action suppressing near-zero modes of H{sub W}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukaya, Hidenori; Hashimoto, Shoji; Kaneko, Takashi

2006-11-01

We propose a lattice action including unphysical Wilson fermions with a negative mass m{sub 0} of the order of the inverse lattice spacing. With this action, the exact zero mode of the Hermitian Wilson-Dirac operator H{sub W}(m{sub 0}) cannot appear and near-zero modes are strongly suppressed. By measuring the spectral density {rho}({lambda}{sub W}), we find a gap near {lambda}{sub W}=0 on the configurations generated with the standard and improved gauge actions. This gap provides a necessary condition for the proof of the exponential locality of the overlap-Dirac operator by Hernandez, Jansen, and Luescher. Since the number of near-zero modes ismore » small, the numerical cost to calculate the matrix sign function of H{sub W}(m{sub 0}) is significantly reduced, and the simulation including dynamical overlap fermions becomes feasible. We also introduce a pair of twisted mass pseudofermions to cancel the unwanted higher mode effects of the Wilson fermions. The gauge coupling renormalization due to the additional fields is then minimized. The topological charge measured through the index of the overlap-Dirac operator is conserved during continuous evolutions of gauge field variables.« less

Understanding school-age obesity: through participatory action research.

PubMed

DiNapoli, Pamela P; Lewis, James B

2008-01-01

This study aimed to assess current levels of overweight (obesity) and fitness among school students using objective data. School-based action research teams were recruited statewide by the New Hampshire Healthy Schools Coalition, the state team of the National Action for Healthy Kids Coalition. Action teams consisted of a physical education teacher, a school nurse, and a school administrator. Data were collected from 6,511 student participants aged 6 to 14 years, which was a representative cross-section from New Hampshire school districts. Key variables of interest in the study were body mass index, and ability to pass five fitness tests using FITNESSGRAM. Pearson's correlation was used to assess the relationships among body mass index, age, gender, and the percent of students that passed FITNESSGRAM tests. The ability of participants to pass the FITNESSGRAM tests declined markedly with age and differed between boys and girls, although the healthy fitness zones for any particular test was lower for girls. Body mass index was significantly negatively correlated with performance on all tests. Age was also statistically negatively correlated with performance on all tests; the relationship between gender and performance on the tests was less striking. Results reflected an increase in the prevalence of overweight school children, even in New Hampshire, which is purported to be one of the healthiest states in the nation. Results offered evidence that body mass index is a valid proxy measure for fitness levels and that fitness programs are necessary to effectively combat the obesity epidemic. Evidence-based changes need to be implemented to address obesity-related factors in schools, because children spend many of their waking hours in that setting. Physical activity during recess and physical education classes could help to increase energy expenditure and develop sound minds and bodies. Schools should consider the development of school-based wellness teams to advise and advocate improved school-based wellness policies. School nurses can take an active part in these initiatives.

Shared Mechanisms in the Estimation of Self-Generated Actions and the Prediction of Other's Actions by Humans.

PubMed

Ikegami, Tsuyoshi; Ganesh, Gowrishankar

2017-01-01

The question of how humans predict outcomes of observed motor actions by others is a fundamental problem in cognitive and social neuroscience. Previous theoretical studies have suggested that the brain uses parts of the forward model (used to estimate sensory outcomes of self-generated actions) to predict outcomes of observed actions. However, this hypothesis has remained controversial due to the lack of direct experimental evidence. To address this issue, we analyzed the behavior of darts experts in an understanding learning paradigm and utilized computational modeling to examine how outcome prediction of observed actions affected the participants' ability to estimate their own actions. We recruited darts experts because sports experts are known to have an accurate outcome estimation of their own actions as well as prediction of actions observed in others. We first show that learning to predict the outcomes of observed dart throws deteriorates an expert's abilities to both produce his own darts actions and estimate the outcome of his own throws (or self-estimation). Next, we introduce a state-space model to explain the trial-by-trial changes in the darts performance and self-estimation through our experiment. The model-based analysis reveals that the change in an expert's self-estimation is explained only by considering a change in the individual's forward model, showing that an improvement in an expert's ability to predict outcomes of observed actions affects the individual's forward model. These results suggest that parts of the same forward model are utilized in humans to both estimate outcomes of self-generated actions and predict outcomes of observed actions.

A Survey Course: The Energy and Mass Budget at the Surface of the Earth.

ERIC Educational Resources Information Center

Association of American Geographers, Washington, DC. Commission on College Geography.

The objectives of this geography course for liberal arts students include the following: 1) to demonstrate cooperative action among sciences, by showing that physical and chemical phenomena occur at biological surfaces that usually exist in economic and cultural frameworks; 2) to show that laboratory principles of mass and energy exchange and…

An Update on Sino-U.S. Relations as Seen through the Chinese Mass Media.

ERIC Educational Resources Information Center

Kang, Jong Geun; Shelby, Maurice E.

To determine the extent to which Chinese mass media reflected official policy concerning U.S.-Sino relations during the six year period after the 1979 normalization of relations, a study examined Chinese newspapers and evaluated their treatment of U.S. actions. News stories, editorials, columns, and features in the Foreign Broadcasting Information…

Optical diametric drive acceleration through action-reaction symmetry breaking

NASA Astrophysics Data System (ADS)

Wimmer, Martin; Regensburger, Alois; Bersch, Christoph; Miri, Mohammad-Ali; Batz, Sascha; Onishchukov, Georgy; Christodoulides, Demetrios N.; Peschel, Ulf

2013-12-01

Newton's third law of motion is one of the pillars of classical physics. This fundamental principle states that the forces two bodies exert on each other are equal and opposite. Had the resulting accelerations been oriented in the same direction, this would have instead led to a counterintuitive phenomenon, that of diametric drive. In such a hypothetical arrangement, two interacting particles constantly accelerate each other in the same direction through a violation of the action-reaction symmetry. Although in classical mechanics any realization of this process requires one of the two particles to have a negative mass and hence is strictly forbidden, it could nevertheless be feasible in periodic structures where the effective mass can also attain a negative sign. Here we report the first experimental observation of such diametric drive acceleration for pulses propagating in a nonlinear optical mesh lattice. The demonstrated reversal of action-reaction symmetry could enable altogether new possibilities for frequency conversion and pulse-steering applications.

Collective judicial management of mass toxic tort controversies: lessons and issues from the Agent Orange litigation.

PubMed

Novey, L B

1988-01-01

Viewing the Agent Orange litigation as a case study, this article explores the feasibility and desirability of strengthening the powers of the courts to manage toxic tort controversies en masse. The Agent Orange lawsuit, brought on behalf of potentially millions of Vietnam War veterans and family members, charged that herbicides used for military purposes during the war caused a wide range of health problems. This article first reviews the current national debate over how mass toxic tort controversies should be handled, including key legislative reform options, and describes how attention is increasingly focused on ways that the court system might better cope with mass toxic torts. The principal events of the Agent Orange litigation are then summarized, by which the litigation was consolidated into a massive class action, the class action was settled, and a streamlined plan for distributing the settlement fund was adopted. The article evaluates the outcome of the litigation, and discusses whether the solution there can and should be broadly applied to other mass toxic tort cases. This question depends, in part, on a series of complex legal and practical issues, but the author suggests that the question will also depend on what institutional role we expect the judiciary to play within society.

Spread of a disease and its effect on population dynamics in an eco-epidemiological system

NASA Astrophysics Data System (ADS)

Upadhyay, Ranjit Kumar; Roy, Parimita

2014-12-01

In this paper, an eco-epidemiological model with simple law of mass action and modified Holling type II functional response has been proposed and analyzed to understand how a disease may spread among natural populations. The proposed model is a modification of the model presented by Upadhyay et al. (2008) [1]. Existence of the equilibria and their stability analysis (linear and nonlinear) has been studied. The dynamical transitions in the model have been studied by identifying the existence of backward Hopf-bifurcations and demonstrated the period-doubling route to chaos when the death rate of predator (μ1) and the growth rate of susceptible prey population (r) are treated as bifurcation parameters. Our studies show that the system exhibits deterministic chaos when some control parameters attain their critical values. Chaotic dynamics is depicted using the 2D parameter scans and bifurcation analysis. Possible implications of the results for disease eradication or its control are discussed.

Mathematical models for principles of gyroscope theory

NASA Astrophysics Data System (ADS)

Usubamatov, Ryspek

2017-01-01

Gyroscope devices are primary units for navigation and control systems that have wide application in engineering. The main property of the gyroscope device is maintaining the axis of a spinning rotor. This gyroscope peculiarity is represented in terms of gyroscope effects in which known mathematical models have been formulated on the law of kinetic energy conservation and the change in the angular momentum. The gyroscope theory is represented by numerous publications, which mathematical models do not match the actual torques and motions in these devices.. The nature of gyroscope effects is more complex than represented in known publications. Recent investigations in this area have demonstrated that on a gyroscope can act until eleven internal torques simultaneously and interdependently around two axes. These gyroscope torques are generated by spinning rotor's mass-elements and by the gyroscope center-mass based on action of several inertial forces. The change in the angular momentum does not play first role for gyroscope motions. The external load generates several internal torques which directions may be distinguished. This situation leads changing of the angular velocities of gyroscope motions around two axes. Formulated mathematical models of gyroscope internal torques are representing the fundamental principle of gyroscope theory. In detail, the gyroscope is experienced the resistance torque generated by the centrifugal and Coriolis forces of the spinning rotor and the precession torque generated by the common inertial forces and the change in the angular momentum. The new mathematical models for the torques and motions of the gyroscope confirmed for most unsolvable problems. The mathematical models practically tested and the results are validated the theoretical approach.

Precision Light Flavor Physics from Lattice QCD

NASA Astrophysics Data System (ADS)

Murphy, David

In this thesis we present three distinct contributions to the study of light flavor physics using the techniques of lattice QCD. These results are arranged into four self-contained papers. The first two papers concern global fits of the quark mass, lattice spacing, and finite volume dependence of the pseudoscalar meson masses and decay constants, computed in a series of lattice QCD simulations, to partially quenched SU(2) and SU(3) chiral perturbation theory (chiPT). These fits determine a subset of the low energy constants of chiral perturbation theory -- in some cases with increased precision, and in other cases for the first time -- which, once determined, can be used to compute other observables and amplitudes in chiPT. We also use our formalism to self-consistently probe the behavior of the (asymptotic) chiral expansion as a function of the quark masses by repeating the fits with different subsets of the data. The third paper concerns the first lattice QCD calculation of the semileptonic K0 → pi-l +nul ( Kl3) form factor at vanishing momentum transfer, f+Kpi(0), with physical mass domain wall quarks. The value of this form factor can be combined with a Standard Model analysis of the experimentally measured K0 → pi -l+nu l decay rate to extract a precise value of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vus, and to test unitarity of the CKM matrix. We also discuss lattice calculations of the pion and kaon decay constants, which can be used to extract Vud through an analogous Standard Model analysis of experimental constraints on leptonic pion and kaon decays. The final paper explores the recently proposed exact one flavor algorithm (EOFA). This algorithm has been shown to drastically reduce the memory footprint required to simulate single quark flavors on the lattice relative to the widely used rational hybrid Monte Carlo (RHMC) algorithm, while also offering modest O(20%) speed-ups. We independently derive the exact one flavor action, explore its equivalence to the RHMC action, and demonstrate that additional preconditioning techniques can be used to significantly accelerate EOFA simulations. We apply EOFA to the ongoing RBC/UKQCD calculation of the Delta I = 1/2 K → pipi decay amplitude, and demonstrate that, in this context, gauge field configurations can be generated a factor of 4.2 times faster using an EOFA-based simulation rather than the previous RHMC-based simulations. We expect that EOFA will help to significantly reduce the statistical error in the first-principles determination of the Standard Model CP-violation parameters epsilon and epsilon' offered by the K → pipi calculation.

Flare-CME characteristics from Sun to Earth combining observations and modeling

NASA Astrophysics Data System (ADS)

Temmer, Manuela; Thalmann, Julia K.; Dissauer, Karin; Veronig, Astrid M.; Tschernitz, Johannes; Hinterreiter, Jürgen; Rodriguez, Luciano

2017-04-01

We analyze the well observed flare-CME event from October 1, 2011 (SOL2011-10-01T09:18) covering the complete chain of action - from Sun to Earth - for a better understanding of the dynamic evolution of the CME and its embedded magnetic field. We study in detail the solar surface and atmosphere from SDO and ground-based instruments associated to the flare-CME and also track the CME signature offlimb from combined EUV and white-light data with STEREO. By applying 3D reconstruction techniques (GCS, total mass) to stereoscopic STEREO-SoHO coronagraph data, we track the temporal and spatial evolution of the CME in interplanetary space and derive its geometry and 3D-mass. We combine the GCS and Lundquist model results to derive the axial flux and helicity of the MC from in situ measurements (Wind). This is compared to nonlinear force-free (NLFF) model results as well as to the reconnected magnetic flux derived from the flare ribbons (flare reconnection flux) and the magnetic flux encompassed by the associated dimming (dimming flux). We find that magnetic reconnection processes were already ongoing before the start of the impulsive flare phase, adding magnetic flux to the flux rope before its final eruption. The dimming flux increases by more than 25% after the end of the flare, indicating that magnetic flux is still added to the flux rope after eruption. Hence, the derived flare reconnection flux is most probably a lower limit for estimating the magnetic flux within the flux rope. We obtain that the magnetic helicity and axial magnetic flux are reduced in interplanetary space by ˜50% and 75%, respectively, possibly indicating to an erosion process. A mass increase of 10% for the CME is observed over the distance range from about 4-20 Rs. The temporal evolution of the CME associated core dimming regions supports the scenario that fast outflows might supply additional mass to the rear part of the CME.

Metabolism, Mass Spectral Analysis and Mode of Action of Trichothecene Mycotoxins.

DTIC Science & Technology

1987-09-15

per billion. An isomer of HT-2 was detected. The mass spectra of H-i (parent and daughter ions) were obtained. Toxic Fusarium isolates were identified...and T-2-tetraol as well as their daughter ion sepctra have been obtained. An isomer of HT-2 ýC-4 acetate) was discovered in a Fusarium culture using...the daughter ions of HT-2 as a probe. Its structure wasdetermined using parent-daughter mass spectra. The detection of the isomer in the Fusarium

Gravity controlled anti-reverse rotation device

DOEpatents

Dickinson, Robert J.; Wetherill, Todd M.

1983-01-01

A gravity assisted anti-reverse rotation device for preventing reverse rotation of pumps and the like. A horizontally mounted pawl is disposed to mesh with a fixed ratchet preventing reverse rotation when the pawl is advanced into intercourse with the ratchet by a vertically mounted lever having a lumped mass. Gravitation action on the lumped mass urges the pawl into mesh with the ratchet, while centrifugal force on the lumped mass during forward, allowed rotation retracts the pawl away from the ratchet.

Changing the Bayesian prior: Absolute neutrino mass constraints in nonlocal gravity*

NASA Astrophysics Data System (ADS)

Dirian, Yves

2017-10-01

Prior change is discussed in observational constraints studies of nonlocally modified gravity, where a model characterized by a modification of the form ˜m2R □-2R to the Einstein-Hilbert action was compared against the base Λ CDM one in a Bayesian way. It was found that the competing modified gravity model is significantly disfavored (at 22 ∶1 in terms of betting-odds) against Λ CDM given CMB +SNIa +BAO data, because of a tension appearing in the H0- ΩM plane. We identify the underlying mechanism generating such a tension and show that it is mostly caused by the late-time, quite smooth, phantom nature of the effective dark energy described by the nonlocal model. We find that the tension is resolved by considering an extension of the initial baseline, consisting in allowing the absolute mass of three degenerated massive neutrino species ∑mν/3 to take values within a prior interval consistent with existing data. As a net effect, the absolute neutrino mass is inferred to be nonvanishing at 2 σ level, best-fitting at ∑mν≈0.21 eV , and the Bayesian tension disappears rendering the nonlocal gravity model statistically equivalent to Λ CDM , given recent CMB +SNIa +BAO data. We also discuss constraints from growth rate measurements f σ8, whose fit is found to be improved by a larger massive neutrino fraction as well. The ν -extended nonlocal model also prefers a higher value of H0 than Λ CDM , therefore in better agreement with local measurements. Our study provides one more example suggesting that the neutrino density fraction Ων is partially degenerated with the nature of the dark energy. This emphasizes the importance of cosmological and terrestrial neutrino research and, as a massive neutrino background impacts structure formation observables non-negligibly, proves to be especially relevant for future galaxy surveys.

Client-oriented Building Mass Customization (CoBMC)

NASA Astrophysics Data System (ADS)

Lee, Xia Sheng; Faris Khamidi, Mohd; Kuppusamy, Sivaraman; Tuck Heng, Chin

2017-12-01

Although much later compared to other industries including aerospace, automobile, oil and gas etc., digital technology development has been cresting towards an exponential curve in the construction industry. Technological diversity and abundance change the game from “what you can” to “what you want”. Society is changing at an unprecedented rate. Consequently adaptability will be crucial. This research paper explores the integration of digital adaptive technologies that transform the construction industry from the mass production to that of a possible client-oriented mass customization. The focus on the design, construction and performance stages of a building project, currently undergoing major overhaul faces a paradigm shift globally that will impact and compel attention for the next three decades with viable solutions such as Building Information Modelling (BIM) to manage massive data cum information. Customization maximizes clients’ participation during the design process thereby achieving greater effective value and higher satisfaction. A study between customized and standardized examples will investigate how adaptive customization will shift the design paradigm from cost to value centric. This action research will explore different aspects of emerging innovative systems already in place pushing the edge of frontiers, and transforming the building industry landscape whether micro or giga, to compliment new technologies to create an unprecedented exhilaration of freshness over the mundane, routine and mediocrity. Three identified fundamental aspects that are instrumental to Client-oriented Building Mass Customization (CoBMC) are design option visualization, parametric product information and n-dimensional modelling. The study concluded that a paradigm shift is therefore inevitable for every stakeholder including clients who will need to re-examine their roles, capabilities, and competencies in preparation towards challenging future.

New cardioprotective agent flokalin and its supramolecular complexes with target amino acids: An integrated mass-spectrometry and quantum-chemical study

NASA Astrophysics Data System (ADS)

Pashynska, Vlada; Stepanian, Stepan; Gömöry, Ágnes; Vékey, Károly; Adamowicz, Ludwik

2017-10-01

This study is devoted to examining the molecular structure and molecular mechanisms of action of the recently developed cardioprotective agent flokalin (Fl), a fluorine containing analogue of pinacidil, which is known as an activator of ATP sensitive potassium membrane channels. A combined experimental and computational investigation of flokalin and its biologically relevant supramolecular complexes with selected amino acids involved in KATP-channels proteins is performed by electrospray ionization mass spectrometry (ESI MS) and by B3LYP/aug-cc-pVDZ quantum-mechanical calculations. First Fl solution is probed by ESI MS and a characteristic mass spectrum of the agent is obtained. Next the intermolecular interactions of Fl with the potentially targeted aminoacids (AA), Lys and Thr, are experimentally investigated. The spectra of the model Fl:AA systems (in 1:1 M ratio) contain information on the ions characteristic to the individual components of the mixtures; though the most interesting spectral results from the biophysical view point are related to the ions of stable molecular clusters formed by flokalin with AA. The peaks of such ions are quite prominent in the spectrum for the Fl:Lys system and less prominent for Fl:Thr. The equilibrium geometries and the corresponding interaction energies of the noncovalent supramolecular complexes registered in the mass spectra are determined in the quantum chemical calculations. The formation of the stable noncovalent complexes of Fl with Lyz and Thr revealed by the ESI MS probing and by the theoretical modelling testify to a possibility of interaction of flokalin with the KATP-channel domains enriched with the two amino acids in biological systems.

Evidence for soft bounds in Ubuntu package sizes and mammalian body masses.

PubMed

Gherardi, Marco; Mandrà, Salvatore; Bassetti, Bruno; Cosentino Lagomarsino, Marco

2013-12-24

The development of a complex system depends on the self-coordinated action of a large number of agents, often determining unexpected global behavior. The case of software evolution has great practical importance: knowledge of what is to be considered atypical can guide developers in recognizing and reacting to abnormal behavior. Although the initial framework of a theory of software exists, the current theoretical achievements do not fully capture existing quantitative data or predict future trends. Here we show that two elementary laws describe the evolution of package sizes in a Linux-based operating system: first, relative changes in size follow a random walk with non-Gaussian jumps; second, each size change is bounded by a limit that is dependent on the starting size, an intriguing behavior that we call "soft bound." Our approach is based on data analysis and on a simple theoretical model, which is able to reproduce empirical details without relying on any adjustable parameter and generates definite predictions. The same analysis allows us to formulate and support the hypothesis that a similar mechanism is shaping the distribution of mammalian body sizes, via size-dependent constraints during cladogenesis. Whereas generally accepted approaches struggle to reproduce the large-mass shoulder displayed by the distribution of extant mammalian species, this is a natural consequence of the softly bounded nature of the process. Additionally, the hypothesis that this model is valid has the relevant implication that, contrary to a common assumption, mammalian masses are still evolving, albeit very slowly.

Investigating the Effects of Mass Media Exposure on the Uptake of Preventive Measures by Hong Kong Residents during the 2015 MERS Outbreak: The Mediating Role of Interpersonal Communication and the Perception of Concern.

PubMed

Ludolph, Ramona; Schulz, Peter J; Chen, Ling

2018-01-01

In 2015, South Korea experienced the largest outbreak to date of the Middle East Respiratory Syndrome (MERS-CoV) outside the Middle East. Fears related to a potential spread of the disease led to an increased alert level as well as heightened media coverage in the neighboring Hong Kong. A cross-sectional survey (N = 533) among residents of Hong Kong was conducted to assess the relationships between the effects of outbreak-related mass media coverage, interpersonal communication, the perceived level of concern in one's close environment, and the uptake of preventive measures. A serial multiple mediator model finds that interpersonal communication and higher perceived concern indirectly influence the effects of media coverage on the engagement in preventive actions. These results expand previous research on the mediating role of interpersonal communication and support assumptions about a modified two-step flow of communication in the context of a public health emergency.

Shared Mechanisms in the Estimation of Self-Generated Actions and the Prediction of Other’s Actions by Humans

PubMed Central

Ganesh, Gowrishankar

2017-01-01

Abstract The question of how humans predict outcomes of observed motor actions by others is a fundamental problem in cognitive and social neuroscience. Previous theoretical studies have suggested that the brain uses parts of the forward model (used to estimate sensory outcomes of self-generated actions) to predict outcomes of observed actions. However, this hypothesis has remained controversial due to the lack of direct experimental evidence. To address this issue, we analyzed the behavior of darts experts in an understanding learning paradigm and utilized computational modeling to examine how outcome prediction of observed actions affected the participants’ ability to estimate their own actions. We recruited darts experts because sports experts are known to have an accurate outcome estimation of their own actions as well as prediction of actions observed in others. We first show that learning to predict the outcomes of observed dart throws deteriorates an expert’s abilities to both produce his own darts actions and estimate the outcome of his own throws (or self-estimation). Next, we introduce a state-space model to explain the trial-by-trial changes in the darts performance and self-estimation through our experiment. The model-based analysis reveals that the change in an expert’s self-estimation is explained only by considering a change in the individual’s forward model, showing that an improvement in an expert’s ability to predict outcomes of observed actions affects the individual’s forward model. These results suggest that parts of the same forward model are utilized in humans to both estimate outcomes of self-generated actions and predict outcomes of observed actions. PMID:29340300

Colloidal motion under the action of a thermophoretic force.

PubMed

Burelbach, Jerome; Zupkauskas, Mykolas; Lamboll, Robin; Lan, Yang; Eiser, Erika

2017-09-07

We present thermophoretic measurements in aqueous suspensions of three different polystyrene (PS) particles of varying negative charge, size, and surface coating. Our measurement technique is based on the observation of the colloidal steady-state distribution using conventional bright-field microscopy, which avoids undesirable effects such as laser-induced convection or local heating. We find that the colloids with the weakest zeta potential exhibit the strongest thermophoretic effect, suggesting that the Soret coefficient has a more intricate dependence on surface functionality than predicted by existing theoretical approaches. We also study the relaxation of the colloids to steady-state and propose a model to quantify the relaxation speed, based on the time evolution of the colloidal center of mass. Our observations are well described by this model and show that the relaxation speed tends to increase with the magnitude of the thermophoretic force.

Colloidal motion under the action of a thermophoretic force

NASA Astrophysics Data System (ADS)

Burelbach, Jerome; Zupkauskas, Mykolas; Lamboll, Robin; Lan, Yang; Eiser, Erika

2017-09-01

We present thermophoretic measurements in aqueous suspensions of three different polystyrene (PS) particles of varying negative charge, size, and surface coating. Our measurement technique is based on the observation of the colloidal steady-state distribution using conventional bright-field microscopy, which avoids undesirable effects such as laser-induced convection or local heating. We find that the colloids with the weakest zeta potential exhibit the strongest thermophoretic effect, suggesting that the Soret coefficient has a more intricate dependence on surface functionality than predicted by existing theoretical approaches. We also study the relaxation of the colloids to steady-state and propose a model to quantify the relaxation speed, based on the time evolution of the colloidal center of mass. Our observations are well described by this model and show that the relaxation speed tends to increase with the magnitude of the thermophoretic force.

Evolution of specialization under non-equilibrium population dynamics.

PubMed

Nurmi, Tuomas; Parvinen, Kalle

2013-03-21

We analyze the evolution of specialization in resource utilization in a mechanistically underpinned discrete-time model using the adaptive dynamics approach. We assume two nutritionally equivalent resources that in the absence of consumers grow sigmoidally towards a resource-specific carrying capacity. The consumers use resources according to the law of mass-action with rates involving trade-off. The resulting discrete-time model for the consumer population has over-compensatory dynamics. We illuminate the way non-equilibrium population dynamics affect the evolutionary dynamics of the resource consumption rates, and show that evolution to the trimorphic coexistence of a generalist and two specialists is possible due to asynchronous non-equilibrium population dynamics of the specialists. In addition, various forms of cyclic evolutionary dynamics are possible. Furthermore, evolutionary suicide may occur even without Allee effects and demographic stochasticity. Copyright © 2013 Elsevier Ltd. All rights reserved.

A rabbit ventricular action potential model replicating cardiac dynamics at rapid heart rates.

PubMed

Mahajan, Aman; Shiferaw, Yohannes; Sato, Daisuke; Baher, Ali; Olcese, Riccardo; Xie, Lai-Hua; Yang, Ming-Jim; Chen, Peng-Sheng; Restrepo, Juan G; Karma, Alain; Garfinkel, Alan; Qu, Zhilin; Weiss, James N

2008-01-15

Mathematical modeling of the cardiac action potential has proven to be a powerful tool for illuminating various aspects of cardiac function, including cardiac arrhythmias. However, no currently available detailed action potential model accurately reproduces the dynamics of the cardiac action potential and intracellular calcium (Ca(i)) cycling at rapid heart rates relevant to ventricular tachycardia and fibrillation. The aim of this study was to develop such a model. Using an existing rabbit ventricular action potential model, we modified the L-type calcium (Ca) current (I(Ca,L)) and Ca(i) cycling formulations based on new experimental patch-clamp data obtained in isolated rabbit ventricular myocytes, using the perforated patch configuration at 35-37 degrees C. Incorporating a minimal seven-state Markovian model of I(Ca,L) that reproduced Ca- and voltage-dependent kinetics in combination with our previously published dynamic Ca(i) cycling model, the new model replicates experimentally observed action potential duration and Ca(i) transient alternans at rapid heart rates, and accurately reproduces experimental action potential duration restitution curves obtained by either dynamic or S1S2 pacing.

Counterregulation of insulin by leptin as key component of autonomic regulation of body weight

PubMed Central

Borer, Katarina T

2014-01-01

A re-examination of the mechanism controlling eating, locomotion, and metabolism prompts formulation of a new explanatory model containing five features: a coordinating joint role of the (1) autonomic nervous system (ANS); (2) the suprachiasmatic (SCN) master clock in counterbalancing parasympathetic digestive and absorptive functions and feeding with sympathetic locomotor and thermogenic energy expenditure within a circadian framework; (3) interaction of the ANS/SCN command with brain substrates of reward encompassing dopaminergic projections to ventral striatum and limbic and cortical forebrain. These drive the nonhomeostatic feeding and locomotor motivated behaviors in interaction with circulating ghrelin and lateral hypothalamic neurons signaling through melanin concentrating hormone and orexin-hypocretin peptides; (4) counterregulation of insulin by leptin of both gastric and adipose tissue origin through: potentiation by leptin of cholecystokinin-mediated satiation, inhibition of insulin secretion, suppression of insulin lipogenesis by leptin lipolysis, and modulation of peripheral tissue and brain sensitivity to insulin action. Thus weight-loss induced hypoleptimia raises insulin sensitivity and promotes its parasympathetic anabolic actions while obesity-induced hyperleptinemia supresses insulin lipogenic action; and (5) inhibition by leptin of bone mineral accrual suggesting that leptin may contribute to the maintenance of stability of skeletal, lean-body, as well as adipose tissue masses. PMID:25317239

To amend the Internal Revenue Code of 1986 to extend the rule providing parity for exclusion from income for employer-provided mass transit and parking benefits.

THOMAS, 113th Congress

Rep. Norton, Eleanor Holmes [D-DC-At Large

2013-12-12

House - 12/12/2013 Referred to the House Committee on Ways and Means. (All Actions) Notes: For further action, see H.R.5771, which became Public Law 113-295 on 12/19/2014. Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Inflammatory cytokines and chemokines, skeletal muscle and polycystic ovary syndrome: effects of pioglitazone and metformin treatment.

PubMed

Ciaraldi, Theodore P; Aroda, Vanita; Mudaliar, Sunder R; Henry, Robert R

2013-11-01

Chronic low-grade inflammation is a common feature of insulin resistant states, including obesity and type 2 diabetes. Less is known about inflammation in Polycystic Ovary Syndrome (PCOS). Thus we evaluated the impact of PCOS on circulating cytokine levels and the effects of anti-diabetic therapies on insulin action, cytokine and chemokine levels and inflammatory signaling in skeletal muscle. Twenty subjects with PCOS and 12 healthy normal cycling (NC) subjects of similar body mass index were studied. PCOS subjects received oral placebo or pioglitazone, 45 mg/d, for 6 months. All PCOS subjects then had metformin, 2 g/day, added to their treatment. Circulating levels of cytokines, chemokines, and adiponectin, skeletal muscle markers of inflammation and phosphorylation of signaling proteins, insulin action evaluated by the hyperinsulinemic/euglycemic clamp procedure and Homeostasis Model Assessment of Insulin Resistance were measured. Circulating levels of a number of cytokines and chemokines were generally similar between PCOS and NC subjects. Levels in PCOS subjects were not altered by pioglitazone or metformin treatment, even though whole body insulin action and adiponectin levels increased with pioglitazone. In spite of the lack of change in levels of cytokines and chemokines, several markers of inflammation in skeletal muscle were improved with Pio treatment. PCOS may represent a state of elevated sensitivity of inflammatory cells in skeletal muscle to cytokines and chemokines, a property that could be reversed by pioglitazone treatment together with improved insulin action. © 2013.

On the relationships between the Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, equilibrium chemistry approximation kinetics, and quadratic kinetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, J. Y.

The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use either of the two are often ambiguous. Here I show that these two kinetics are special approximations to the equilibrium chemistry approximation (ECA) kinetics, which is the first-order approximation to the quadratic kinetics that solves the equation of an enzyme–substrate complex exactly for a single-enzyme and single-substrate biogeochemical reaction with the law of mass action and the assumption of a quasi-steadymore » state for the enzyme–substrate complex and that the product genesis from enzyme–substrate complex is much slower than the equilibration between enzyme–substrate complexes, substrates, and enzymes. In particular, I show that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in deriving the equilibrium chemistry approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln k 2 + of the reaction velocity v with respect to the maximum product genesis rate k 2 +, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln k 1 + of v with respect to the intrinsic substrate affinity k 1 +, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln [ E] T of v with respect the total enzyme concentration [ E] T, and persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln [ S] T of v with respect to the total substrate concentration [ S] T. Meanwhile, the reverse Michaelis–Menten kinetics persistently underpredicts ∂ ln v / ∂ ln k 2 + and ∂ ln v / ∂ ln [ E] T, and persistently overpredicts ∂ ln v / ∂ ln k 1 + and ∂ ln v / ∂ ln [ S] T. In contrast, the equilibrium chemistry approximation kinetics always gives consistent predictions of ∂ ln v / ∂ ln k 2 +, ∂ ln v / ∂ ln k 1 +, ∂ ln v / ∂ ln [ E] T, and ∂ ln v / ∂ ln [ S] T, indicating that ECA-based models will be more calibratable if the modeled processes do obey the law of mass action. Since the equilibrium chemistry approximation kinetics includes advantages from both the Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics and it is applicable for almost the whole range of substrate and enzyme abundances, land biogeochemical modelers therefore no longer need to choose when to use the Michaelis–Menten kinetics or the reverse Michaelis–Menten kinetics. I expect that removing this choice ambiguity will make it easier to formulate more robust and consistent land biogeochemical models.« less

On the relationships between the Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, equilibrium chemistry approximation kinetics, and quadratic kinetics

DOE PAGES

Tang, J. Y.

2015-12-01

The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use either of the two are often ambiguous. Here I show that these two kinetics are special approximations to the equilibrium chemistry approximation (ECA) kinetics, which is the first-order approximation to the quadratic kinetics that solves the equation of an enzyme–substrate complex exactly for a single-enzyme and single-substrate biogeochemical reaction with the law of mass action and the assumption of a quasi-steadymore » state for the enzyme–substrate complex and that the product genesis from enzyme–substrate complex is much slower than the equilibration between enzyme–substrate complexes, substrates, and enzymes. In particular, I show that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in deriving the equilibrium chemistry approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln k 2 + of the reaction velocity v with respect to the maximum product genesis rate k 2 +, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln k 1 + of v with respect to the intrinsic substrate affinity k 1 +, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln [ E] T of v with respect the total enzyme concentration [ E] T, and persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln [ S] T of v with respect to the total substrate concentration [ S] T. Meanwhile, the reverse Michaelis–Menten kinetics persistently underpredicts ∂ ln v / ∂ ln k 2 + and ∂ ln v / ∂ ln [ E] T, and persistently overpredicts ∂ ln v / ∂ ln k 1 + and ∂ ln v / ∂ ln [ S] T. In contrast, the equilibrium chemistry approximation kinetics always gives consistent predictions of ∂ ln v / ∂ ln k 2 +, ∂ ln v / ∂ ln k 1 +, ∂ ln v / ∂ ln [ E] T, and ∂ ln v / ∂ ln [ S] T, indicating that ECA-based models will be more calibratable if the modeled processes do obey the law of mass action. Since the equilibrium chemistry approximation kinetics includes advantages from both the Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics and it is applicable for almost the whole range of substrate and enzyme abundances, land biogeochemical modelers therefore no longer need to choose when to use the Michaelis–Menten kinetics or the reverse Michaelis–Menten kinetics. I expect that removing this choice ambiguity will make it easier to formulate more robust and consistent land biogeochemical models.« less

[A Structural Equation Model of Pressure Ulcer Prevention Action in Clinical Nurses].

PubMed

Lee, Sook Ja; Park, Ok Kyoung; Park, Mi Yeon

2016-08-01

The purpose of this study was to construct and test a structural equation model for pressure ulcer prevention action by clinical nurses. The Health Belief Model and the Theory of Planned Behavior were used as the basis for the study. A structured questionnaire was completed by 251 clinical nurses to analyze the relationships between concepts of perceived benefits, perceived barriers, attitude, subjective norm, perceived control, intention to perform action and behavior. SPSS 22.0 and AMOS 22.0 programs were used to analyze the efficiency of the hypothesized model and calculate the direct and indirect effects of factors affecting pressure ulcer prevention action among clinical nurses. The model fitness statistics of the hypothetical model fitted to the recommended levels. Attitude, subjective norm and perceived control on pressure ulcer prevention action explained 64.2% for intention to perform prevention action. The major findings of this study indicate that it is essential to recognize improvement in positive attitude for pressure ulcer prevention action and a need for systematic education programs to increase perceived control for prevention action.

"More Complicated than a Numbers Game": A Critical Race Theory Examination of Asian Americans and Campus Racial Climate

ERIC Educational Resources Information Center

Poon, Oi Yan Anita

2010-01-01

In the Grutter and Gratz Supreme Court decision, proponents of affirmative action claimed that a critical mass of minority students could effectively counter racial marginalization often experienced by students of color due to their racial status. On some campuses, Asian Americans as a pan-ethnic population enjoy a critical mass in undergraduate…

Tadpole-improved SU(2) lattice gauge theory

NASA Astrophysics Data System (ADS)

Shakespeare, Norman H.; Trottier, Howard D.

1999-01-01

A comprehensive analysis of tadpole-improved SU(2) lattice gauge theory is made. Simulations are done on isotropic and anisotropic lattices, with and without improvement. Two tadpole renormalization schemes are employed, one using average plaquettes, the other using mean links in the Landau gauge. Simulations are done with spatial lattice spacings as in the range of about 0.1-0.4 fm. Results are presented for the static quark potential, the renormalized lattice anisotropy at/as (where at is the ``temporal'' lattice spacing), and for the scalar and tensor glueball masses. Tadpole improvement significantly reduces discretization errors in the static quark potential and in the scalar glueball mass, and results in very little renormalization of the bare anisotropy that is input to the action. We also find that tadpole improvement using mean links in the Landau gauge results in smaller discretization errors in the scalar glueball mass (as well as in the static quark potential), compared to when average plaquettes are used. The possibility is also raised that further improvement in the scalar glueball mass may result when the coefficients of the operators which correct for discretization errors in the action are computed beyond the tree level.

The plasticity of clays

USGS Publications Warehouse

Group, F.F.

1905-01-01

(1) Sand injures plasticity little at first because the grains are suspended in a plastic mass. It is only when grains are abundant enough to come in contact with their neighbors, that the effect becomes serious, and then both strength and amount of possible flow are injured. (2) Certain rare organic colloids increase the plasticity by rendering the water viscous. (3) Fineness also tends to increase plasticity. (4) Plane surfaces (plates) increase the amount of possible flow. They also give a chance for lubrication by thinner films, thus increasing the friction of film, and the strength of the whole mass. The action of plates is thus twofold ; but fineness may be carried to such an extent as to break up plate-like grains into angular fragments. The beneficial effects of plates are also decreased by the fact that each is so closely surrounded by others in the mass. (5) Molecular attraction is twofold in increasing plasticity. As the attraction increases, the coherence and strength of the mass increase, and the amount of possible deformation before crumbling also increases. Fineness increases this action by requiring more water. Colloids and crystalloids in solution may also increase the attraction. It is thus seen to be more active than any other single factor.

Insights into the disparate action of osmolytes and macromolecular crowders on amyloid formation

PubMed Central

Sukenik, Shahar

2012-01-01

It is widely recognized that amyloid formation sensitively responds to conditions set by myriad cellular solutes. These cosolutes include two important classes: macromolecular crowders and compatible osmolytes. We have recently found that addition of macromolecular PEG only slightly affects fibril formation of a model peptide in vitro. Polyol osmolytes, in contrast, lengthen the lag time for aggregation, and lead to larger fibril mass at equilibrium. To further hypothesize on the molecular underpinnings of the disparate effect of the two cosolute classes, we have further analyzed the experiments using an available kinetic mechanism describing fibril aggregation. Model calculations suggest that all cosolutes similarly lengthen the time required for nucleation, possibly due to their excluded volume effect. However, PEGs may in addition promote fibril fragmentation, leading to lag times that are overall almost unvaried. Moreover, polyols effectively slow the monomer-fibril detachment rates, thereby favoring additional fibril formation. Our analysis provides first hints that cosolutes act not only by changing association or dissociation rates, but potentially also by directing the formation of fibrils of varied morphologies with different mechanical properties. Although additional experiments are needed to unambiguously resolve the action of excluded cosolutes on amyloid formation, it is becoming clear that these compounds are important to consider in the search for ways to modulate fibril formation. PMID:22453174

Learning reliable manipulation strategies without initial physical models

NASA Technical Reports Server (NTRS)

Christiansen, Alan D.; Mason, Matthew T.; Mitchell, Tom M.

1990-01-01

A description is given of a robot, possessing limited sensory and effectory capabilities but no initial model of the effects of its actions on the world, that acquires such a model through exploration, practice, and observation. By acquiring an increasingly correct model of its actions, it generates increasingly successful plans to achieve its goals. In an apparently nondeterministic world, achieving reliability requires the identification of reliable actions and a preference for using such actions. Furthermore, by selecting its training actions carefully, the robot can significantly improve its learning rate.

Feedback, Mass Conservation and Reaction Kinetics Impact the Robustness of Cellular Oscillations

PubMed Central

Baum, Katharina; Kofahl, Bente; Steuer, Ralf; Wolf, Jana

2016-01-01

Oscillations occur in a wide variety of cellular processes, for example in calcium and p53 signaling responses, in metabolic pathways or within gene-regulatory networks, e.g. the circadian system. Since it is of central importance to understand the influence of perturbations on the dynamics of these systems a number of experimental and theoretical studies have examined their robustness. The period of circadian oscillations has been found to be very robust and to provide reliable timing. For intracellular calcium oscillations the period has been shown to be very sensitive and to allow for frequency-encoded signaling. We here apply a comprehensive computational approach to study the robustness of period and amplitude of oscillatory systems. We employ different prototype oscillator models and a large number of parameter sets obtained by random sampling. This framework is used to examine the effect of three design principles on the sensitivities towards perturbations of the kinetic parameters. We find that a prototype oscillator with negative feedback has lower period sensitivities than a prototype oscillator relying on positive feedback, but on average higher amplitude sensitivities. For both oscillator types, the use of Michaelis-Menten instead of mass action kinetics in all degradation and conversion reactions leads to an increase in period as well as amplitude sensitivities. We observe moderate changes in sensitivities if replacing mass conversion reactions by purely regulatory reactions. These insights are validated for a set of established models of various cellular rhythms. Overall, our work highlights the importance of reaction kinetics and feedback type for the variability of period and amplitude and therefore for the establishment of predictive models. PMID:28027301

A Positive Cosmological Constant as Centrifugal Force in an Expanding Kantian Model of the Universe

NASA Astrophysics Data System (ADS)

Sternglass, E. J.

1998-05-01

Recent redshift measurements of distant Type Ia supernovae appear to indicate that cosmic expansion has speeded up since these distant stars exploded, rather than slowing down under the action of gravity. These results suggest the existence of a repulsive force as originally assumed by Einstein through the introduction of the lambda constant. Such a repulsive force arises naturally as centrifugal force in the evolution of a hierarchically organized cosmological model involving a series of rotating structures of increasing size as originally suggested by Kant in the 18th century when combined with the idea of Lemaitre, according to which the universe and the observed systems arose in the course of repeated divisions by two of a primeval atom. As described in the AIP Conference Proceedings 254,105 (1992), if this atom is assumed to be a highly relativistic form of positronium or "quarkonium" at the Planck density one avoids an initial singularity and requires no other particles. The division process takes place in 27 stages of 10 divisions each beginning with a lower mass excited state of the original Lemaitre atom that forms a central cluster in which a quarter of the particles are initially retained. One then arrives at a model in which all structures are laid down in the form of massive "cold dark matter" during a period of exponential growth or inflation before the Big Bang, leading to an ultimately stable, closed "flat" universe of finite mass that explains the masses, sizes, rotational and expansion velocities and thus the Hubble constants of the various systems as well as the age of the universe since the Big Bang in good agreement with observations, using only e, mo, c and h.

Exciton center-of-mass localization and dielectric environment effect in monolayer WS2

NASA Astrophysics Data System (ADS)

Hichri, Aïda; Ben Amara, Imen; Ayari, Sabrine; Jaziri, Sihem

2017-06-01

The ultrathin transition metal dichalcogenides (TMDs) have emerged as promising materials for various applications using two dimensional semiconductors. They have attracted increasing attention due to their unique optical properties originate from neutral and charged excitons. In this paper, we study the strong localization of exciton center-of-mass motion within random potential fluctuations caused by the monolayer defects. Here, we report negatively charged exciton formation in monolayer TMDs, notably tungsten disulfide WS2. Our theory is based on an effective mass model of neutral and charged excitons, parameterized by ab-initio calculations. Taking into the account the strong correlation between the monolayer WS2 and the surrounding dielectric environment, our theoretical results are in good agreement with one-photon photoluminescence (PL) and reflectivity measurements. We also show that the exciton state with p-symmetry, experimentally observed by two-photon PL emission, is energetically below the 2s-state. We use the equilibrium mass action law, to quantify the relative weight of exciton and trion PL. We show that exciton and trion emission can be tuned and controlled by external parameters like temperature, pumping, and injection electrons. Finally, in comparison with experimental measurements, we show that exciton emission in monolayer tungsten dichalcogenides is substantially reduced. This feature suggests that free exciton can be trapped in disordered potential wells to form a localized exciton and therefore offers a route toward novel optical properties.

Direct computation of thermodynamic properties of chemically reacting air with consideration to CFD

NASA Astrophysics Data System (ADS)

Iannelli, Joe

2003-10-01

This paper details a two-equation procedure to calculate exactly mass and mole fractions, pressure, temperature, specific heats, speed of sound and the thermodynamic and jacobian partial derivatives of pressure and temperature for a five-species chemically reacting equilibrium air. The procedure generates these thermodynamic properties using as independent variables either pressure and temperature or density and internal energy, for CFD applications. An original element in this procedure consists in the exact physically meaningful solution of the mass-fraction and mass-action equations. Air-equivalent molecular masses for oxygen and nitrogen are then developed to account, within a mixture of only oxygen and nitrogen, for the presence of carbon dioxide, argon and the other noble gases within atmospheric air. The mathematical formulation also introduces a versatile system non-dimensionalization that makes the procedure uniformly applicable to flows ranging from shock-tube flows with zero initial velocity to aerothermodynamic flows with supersonic/hypersonic free-stream Mach numbers. Over a temperature range of more than 10000 K and pressure and density ranges corresponding to an increase in altitude in standard atmosphere of 30000 m above sea level, the predicted distributions of mole fractions, constant-volume specific heat, and speed of sound for the model five species agree with independently published results, and all the calculated thermodynamic properties, including their partial derivatives, remain continuous, smooth, and physically meaningful.

INTERACTION OF LASER RADIATION WITH MATTER: Calculation of the kinetics of heating and structural changes in the cartilaginous tissue under the action of laser radiation

NASA Astrophysics Data System (ADS)

Sobol', E. N.; Kitai, M. S.

1998-07-01

A theoretical model is developed for the calculation of the temperature fields and determination of the size of a zone with structural changes in the cartilaginous tissue. The model is based on a simultaneous analysis of the heat and mass transfer processes and it takes into account the bulk absorption of laser radiation by the tissue, surface evaporation of water, and temperature dependences of the diffusion coefficients. It is assumed that under the influence of a phase transition between free and bound water, caused by heating of the cartilage to 70°C, the proteoglycans of the cartilage matrix become mobile and, as a result of such mass transfer, structural changes are induced in the cartilaginous tissue causing relaxation of stresses or denaturation. It is shown that the maximum temperature is then reached not on the irradiated surface but at some distance from it, and that the size of the zones of structural changes (denaturation depth) depends strongly on the energy density of the laser radiation and its wavelength, on the duration of the irradiation, and on the cartilage thickness. This model makes it possible to calculate the temperature fields and the depth of structural changes in laser-induced relaxation of stresses and changes in the shape of the cartilaginous tissue.

Resolving the multifaceted mechanisms of the ferric chloride thrombosis model using an interdisciplinary microfluidic approach

PubMed Central

Ciciliano, Jordan C.; Sakurai, Yumiko; Myers, David R.; Fay, Meredith E.; Hechler, Beatrice; Meeks, Shannon; Li, Renhao; Dixon, J. Brandon; Lyon, L. Andrew; Gachet, Christian

2015-01-01

The mechanism of action of the widely used in vivo ferric chloride (FeCl3) thrombosis model remains poorly understood; although endothelial cell denudation is historically cited, a recent study refutes this and implicates a role for erythrocytes. Given the complexity of the in vivo environment, an in vitro reductionist approach is required to systematically isolate and analyze the biochemical, mass transfer, and biological phenomena that govern the system. To this end, we designed an “endothelial-ized” microfluidic device to introduce controlled FeCl3 concentrations to the molecular and cellular components of blood and vasculature. FeCl3 induces aggregation of all plasma proteins and blood cells, independent of endothelial cells, by colloidal chemistry principles: initial aggregation is due to binding of negatively charged blood components to positively charged iron, independent of biological receptor/ligand interactions. Full occlusion of the microchannel proceeds by conventional pathways, and can be attenuated by antithrombotic agents and loss-of-function proteins (as in IL4-R/Iba mice). As elevated FeCl3 concentrations overcome protective effects, the overlap between charge-based aggregation and clotting is a function of mass transfer. Our physiologically relevant in vitro system allows us to discern the multifaceted mechanism of FeCl3-induced thrombosis, thereby reconciling literature findings and cautioning researchers in using the FeCl3 model. PMID:25931587

Modelling Dowel Action of Discrete Reinforcing Bars in Cracked Concrete Structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kwan, A. K. H.; Ng, P. L.; Lam, J. Y. K.

2010-05-21

Dowel action is one of the component actions for shear force transfer in cracked reinforced concrete. In finite element analysis of concrete structures, the use of discrete representation of reinforcing bars is considered advantageous over the smeared representation due to the relative ease of modelling the bond-slip behaviour. However, there is very limited research on how to simulate the dowel action of discrete reinforcing bars. Herein, a numerical model for dowel action of discrete reinforcing bars crossing cracks in concrete is developed. The model features the derivation of dowel stiffness matrix based on beam-on-elastic-foundation theory and the direct assemblage ofmore » dowel stiffness into the concrete element stiffness matrices. The dowel action model is incorporated in a nonlinear finite element programme with secant stiffness formulation. Deep beams tested in the literature are analysed and it is found that the incorporation of dowel action model improves the accuracy of analysis.« less

Cost-effective binomial sequential sampling of western bean cutworm, Striacosta albicosta (Lepidoptera: Noctuidae), egg masses in corn.

PubMed

Paula-Moraes, S; Burkness, E C; Hunt, T E; Wright, R J; Hein, G L; Hutchison, W D

2011-12-01

Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a native pest of dry beans (Phaseolus vulgaris L.) and corn (Zea mays L.). As a result of larval feeding damage on corn ears, S. albicosta has a narrow treatment window; thus, early detection of the pest in the field is essential, and egg mass sampling has become a popular monitoring tool. Three action thresholds for field and sweet corn currently are used by crop consultants, including 4% of plants infested with egg masses on sweet corn in the silking-tasseling stage, 8% of plants infested with egg masses on field corn with approximately 95% tasseled, and 20% of plants infested with egg masses on field corn during mid-milk-stage corn. The current monitoring recommendation is to sample 20 plants at each of five locations per field (100 plants total). In an effort to develop a more cost-effective sampling plan for S. albicosta egg masses, several alternative binomial sampling plans were developed using Wald's sequential probability ratio test, and validated using Resampling for Validation of Sampling Plans (RVSP) software. The benefit-cost ratio also was calculated and used to determine the final selection of sampling plans. Based on final sampling plans selected for each action threshold, the average sample number required to reach a treat or no-treat decision ranged from 38 to 41 plants per field. This represents a significant savings in sampling cost over the current recommendation of 100 plants.

Are atmospheric updrafts a key to unlocking climate forcing and sensitivity?

DOE PAGES

Donner, Leo J.; O'Brien, Travis A.; Rieger, Daniel; ...

2016-10-20

Both climate forcing and climate sensitivity persist as stubborn uncertainties limiting the extent to which climate models can provide actionable scientific scenarios for climate change. A key, explicit control on cloud–aerosol interactions, the largest uncertainty in climate forcing, is the vertical velocity of cloud-scale updrafts. Model-based studies of climate sensitivity indicate that convective entrainment, which is closely related to updraft speeds, is an important control on climate sensitivity. Updraft vertical velocities also drive many physical processes essential to numerical weather prediction. Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climatemore » and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climate and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying vs in climate models may capture this behavior, but it has not been accounted for when parameterizing cloud and precipitation processes in current models. New observations of convective vertical velocities offer a potentially promising path toward developing process-level cloud models and parameterizations for climate and numerical weather prediction. Taking account of the scale dependence of resolved vertical velocities offers a path to matching cloud-scale physical processes and their driving dynamics more realistically, with a prospect of reduced uncertainty in both climate forcing and sensitivity.« less

Are atmospheric updrafts a key to unlocking climate forcing and sensitivity?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donner, Leo J.; O'Brien, Travis A.; Rieger, Daniel

Both climate forcing and climate sensitivity persist as stubborn uncertainties limiting the extent to which climate models can provide actionable scientific scenarios for climate change. A key, explicit control on cloud–aerosol interactions, the largest uncertainty in climate forcing, is the vertical velocity of cloud-scale updrafts. Model-based studies of climate sensitivity indicate that convective entrainment, which is closely related to updraft speeds, is an important control on climate sensitivity. Updraft vertical velocities also drive many physical processes essential to numerical weather prediction. Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climatemore » and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying Vertical velocities and their role in atmospheric physical processes have been given very limited attention in models for climate and numerical weather prediction. The relevant physical scales range down to tens of meters and are thus frequently sub-grid and require parameterization. Many state-of-science convection parameterizations provide mass fluxes without specifying vs in climate models may capture this behavior, but it has not been accounted for when parameterizing cloud and precipitation processes in current models. New observations of convective vertical velocities offer a potentially promising path toward developing process-level cloud models and parameterizations for climate and numerical weather prediction. Taking account of the scale dependence of resolved vertical velocities offers a path to matching cloud-scale physical processes and their driving dynamics more realistically, with a prospect of reduced uncertainty in both climate forcing and sensitivity.« less

A model for production, perception, and acquisition of actions in face-to-face communication.

PubMed

Kröger, Bernd J; Kopp, Stefan; Lowit, Anja

2010-08-01

The concept of action as basic motor control unit for goal-directed movement behavior has been used primarily for private or non-communicative actions like walking, reaching, or grasping. In this paper, literature is reviewed indicating that this concept can also be used in all domains of face-to-face communication like speech, co-verbal facial expression, and co-verbal gesturing. Three domain-specific types of actions, i.e. speech actions, facial actions, and hand-arm actions, are defined in this paper and a model is proposed that elucidates the underlying biological mechanisms of action production, action perception, and action acquisition in all domains of face-to-face communication. This model can be used as theoretical framework for empirical analysis or simulation with embodied conversational agents, and thus for advanced human-computer interaction technologies.

Integrating Research into Decision Making: Providing Examples for an Informal Action Research Model. Research Report No. 83-24.

ERIC Educational Resources Information Center

Losak, John; Morris, Cathy

One promising avenue for increasing the utilization of institutional research data is the informal action research model. While formal action research stresses the involvement of researchers throughout the decision-making process, the informal model stresses participation in the later stages of decision making. Informal action research requires…

Nambu sigma model and effective membrane actions

NASA Astrophysics Data System (ADS)

Jurčo, Branislav; Schupp, Peter

2012-07-01

We propose an effective action for a p‧-brane with open p-branes ending on it. The action has dual descriptions similar to the commutative and non-commutative ones of the DBI action for D-branes and open strings. The Poisson structure governing the non-commutativity of the D-brane is replaced by a Nambu structure and the open-closed string relations are generalized to the case of p-branes utilizing a novel Nambu sigma model description of p-branes. In the case of an M5-brane our action interpolates between M5-actions already proposed in the literature and matrix-model like actions involving Nambu structures.

The mass-action law based algorithms for quantitative econo-green bio-research.

PubMed

Chou, Ting-Chao

2011-05-01

The relationship between dose and effect is not random, but rather governed by the unified theory based on the median-effect equation (MEE) of the mass-action law. Rearrangement of MEE yields the mathematical form of the Michaelis-Menten, Hill, Henderson-Hasselbalch and Scatchard equations of biochemistry and biophysics, and the median-effect plot allows linearization of all dose-effect curves regardless of potency and shape. The "median" is the universal common-link and reference-point for the 1st-order to higher-order dynamics, and from single-entities to multiple-entities and thus, it allows the all for one and one for all unity theory to "integrate" simple and complex systems. Its applications include the construction of a dose-effect curve with a theoretical minimum of only two data points if they are accurately determined; quantification of synergism or antagonism at all dose and effect levels; the low-dose risk assessment for carcinogens, toxic substances or radiation; and the determination of competitiveness and exclusivity for receptor binding. Since the MEE algorithm allows the reduced requirement of the number of data points for small size experimentation, and yields quantitative bioinformatics, it points to the deterministic, efficient, low-cost biomedical research and drug discovery, and ethical planning for clinical trials. It is concluded that the contemporary biomedical sciences would greatly benefit from the mass-action law based "Green Revolution".

The opportunistic transmission of wireless worms between mobile devices

NASA Astrophysics Data System (ADS)

Rhodes, C. J.; Nekovee, M.

2008-12-01

The ubiquity of portable wireless-enabled computing and communications devices has stimulated the emergence of malicious codes (wireless worms) that are capable of spreading between spatially proximal devices. The potential exists for worms to be opportunistically transmitted between devices as they move around, so human mobility patterns will have an impact on epidemic spread. The scenario we address in this paper is proximity attacks from fleetingly in-contact wireless devices with short-range communication range, such as Bluetooth-enabled smart phones. An individual-based model of mobile devices is introduced and the effect of population characteristics and device behaviour on the outbreak dynamics is investigated. The model uses straight-line motion to achieve population, though it is recognised that this is a highly simplified representation of human mobility patterns. We show that the contact rate can be derived from the underlying mobility model and, through extensive simulation, that mass-action epidemic models remain applicable to worm spreading in the low density regime studied here. The model gives useful analytical expressions against which more refined simulations of worm spread can be developed and tested.

Metabolomics-based mechanisms exploration of Huang-Lian Jie-Du decoction on cerebral ischemia via UPLC-Q-TOF/MS analysis on rat serum.

PubMed

Zhu, Baojie; Cao, Huiting; Sun, Limin; Li, Bo; Guo, Liwei; Duan, Jinao; Zhu, Huaxu; Zhang, Qichun

2018-04-24

Huang-Lian Jie-Du decoction (HLJDD), a traditional formula of Chinese medicine constituted with Rhizoma Coptidis, RadixScutellariae, CortexPhellodendri amurensis and Fructus Gardeniae, exhibits unambiguous therapeutic effect on cerebral ischemia via multi-targets action. Further investigation, however, is still required to explore the relationship between those mechanisms and targets through system approaches. Rats of cerebral ischemia were completed by middle cerebral artery occlusion (MCAO) with reperfusion. Following evaluation of pharmacological actions of HLJDD on MCAO rats, the plasma samples from rats of control, MCAO and HLJDD-treated MCAO groups were prepared strictly and subjected to ultra-performance liquid chromatography quadrupole time of flight mass spectrometry for metabolites analysis. The raw mass data were imported to MassLynx software for peak detection and alignment, and further introduced to EZinfo 2.0 software for orthogonal projection to latent structures analysis, principal component analysis and partial least-squares-discriminant analysis. The metabolic pathways assay of those potential biomarkers were performed with MetaboAnalyst through the online database, HMDB, Metlin, KEGG and SMPD. Those intriguing metabolic pathways were further investigated via biochemical assay. HLJDD ameliorated the MCAO-induce cerebral damage and blocked the severe inflammation response. There were nineteen different biomarkers identified among control, MCAO and HLJDD-treated MCAO groups. Ten metabolic pathways were proposed from these significant metabolites. Incorporation with the biochemical assay of cerebral tissue, modulation of metabolic stress, regulation glutamate/GABA-glutamine cycle and enhancement of cholinergic neurons function were explored that involved in the actions of HLJDD on cerebral ischemia. HLJDD achieves therapeutic action on cerebral ischemia via coordinating the basic pathophysiological network of metabolic stress, glutamate metabolism, and acetylcholine levels and function. Copyright © 2018 Elsevier B.V. All rights reserved.

A neural network model of causative actions.

PubMed

Lee-Hand, Jeremy; Knott, Alistair

2015-01-01

A common idea in models of action representation is that actions are represented in terms of their perceptual effects (see e.g., Prinz, 1997; Hommel et al., 2001; Sahin et al., 2007; Umiltà et al., 2008; Hommel, 2013). In this paper we extend existing models of effect-based action representations to account for a novel distinction. Some actions bring about effects that are independent events in their own right: for instance, if John smashes a cup, he brings about the event of the cup smashing. Other actions do not bring about such effects. For instance, if John grabs a cup, this action does not cause the cup to "do" anything: a grab action has well-defined perceptual effects, but these are not registered by the perceptual system that detects independent events involving external objects in the world. In our model, effect-based actions are implemented in several distinct neural circuits, which are organized into a hierarchy based on the complexity of their associated perceptual effects. The circuit at the top of this hierarchy is responsible for actions that bring about independently perceivable events. This circuit receives input from the perceptual module that recognizes arbitrary events taking place in the world, and learns movements that reliably cause such events. We assess our model against existing experimental observations about effect-based motor representations, and make some novel experimental predictions. We also consider the possibility that the "causative actions" circuit in our model can be identified with a motor pathway reported in other work, specializing in "functional" actions on manipulable tools (Bub et al., 2008; Binkofski and Buxbaum, 2013).

Higgs mechanism for gravity. II. Higher spin connections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boulanger, Nicolas; Kirsch, Ingo; Jefferson Laboratory of Physics, Harvard University, Cambridge, Massachusetts 02138

We continue the work of [Phys. Rev. D 72, 024001 (2005)] in which gravity is considered as the Goldstone realization of a spontaneously broken diffeomorphism group. We complete the discussion of the coset space Diff (d,R)/SO(1,d-1) formed by the d-dimensional group of analytic diffeomorphisms and the Lorentz group. We find that this coset space is parametrized by coordinates, a metric, and an infinite tower of higher-spin or generalized connections. We then study effective actions for the corresponding symmetry breaking which gives mass to the higher spin connections. Our model predicts that gravity is modified at high energies by the exchangemore » of massive higher spin particles.« less

Potassium-cobalt sulphate crystal growth assisted by low frequency vibrations

NASA Astrophysics Data System (ADS)

Sadovsky, A.; Ermochenkov, I.; Dubovenko, E.; Sukhanova, E.; Bebyakin, M.; Dubov, V.; Avetissov, I.

2018-02-01

Single crystals of K2Co(SO4)2·6H2O were grown from solution using the temperature reduction method enhanced by the axial low frequency vibration control technique (AVC-technique). Physical modeling of heat-mass transfer in solution under the AVC action was performed. The growth rate of the AVC grown crystal was found to be twice that of the crystal grown under natural convection conditions. Analysis of spectral characteristics (absorption and Raman spectra) as well as structural properties (dislocation density and microhardness) of the grown crystals showed the significant superiority of the AVC technique for the growth of K2Co(SO4)2·6H2O crystals.

Thermodynamics of "exotic" Bañados-Teitelboim-Zanelli black holes.

PubMed

Townsend, Paul K; Zhang, Baocheng

2013-06-14

A number of three-dimensional (3D) gravity models, such as 3D conformal gravity, admit "exotic" black hole solutions: the metric is the same as the Bañados-Teitelboim-Zanelli metric of 3D Einstein gravity but with reversed roles for mass and angular momentum, and an entropy proportional to the length of the inner horizon instead of the event horizon. Here we show that the Bañados-Teitelboim-Zanelli solutions of the exotic 3D Einstein gravity (with parity-odd action but Einstein field equations) are exotic black holes, and we investigate their thermodynamics. The first and second laws of black hole thermodynamics still apply, and the entropy still has a statistical interpretation.

From Discrete Space-Time to Minkowski Space: Basic Mechanisms, Methods and Perspectives

NASA Astrophysics Data System (ADS)

Finster, Felix

This survey article reviews recent results on fermion systems in discrete space-time and corresponding systems in Minkowski space. After a basic introduction to the discrete setting, we explain a mechanism of spontaneous symmetry breaking which leads to the emergence of a discrete causal structure. As methods to study the transition between discrete space-time and Minkowski space, we describe a lattice model for a static and isotropic space-time, outline the analysis of regularization tails of vacuum Dirac sea configurations, and introduce a Lorentz invariant action for the masses of the Dirac seas. We mention the method of the continuum limit, which allows to analyze interacting systems. Open problems are discussed.

Covariant approach of perturbations in Lovelock type brane gravity

NASA Astrophysics Data System (ADS)

Bagatella-Flores, Norma; Campuzano, Cuauhtemoc; Cruz, Miguel; Rojas, Efraín

2016-12-01

We develop a covariant scheme to describe the dynamics of small perturbations on Lovelock type extended objects propagating in a flat Minkowski spacetime. The higher-dimensional analogue of the Jacobi equation in this theory becomes a wave type equation for a scalar field Φ . Whithin this framework, we analyse the stability of membranes with a de Sitter geometry where we find that the Jacobi equation specializes to a Klein-Gordon (KG) equation for Φ possessing a tachyonic mass. This shows that, to some extent, these types of extended objects share the symmetries of the Dirac-Nambu-Goto (DNG) action which is by no means coincidental because the DNG model is the simplest included in this type of gravity.

Modeling of Gate Bias Modulation in Carbon Nanotube Field-Effect-Transistor

NASA Technical Reports Server (NTRS)

Toshishige, Yamada; Biegel, Bryan A. (Technical Monitor)

2002-01-01

The threshold voltages of a carbon-nanotube (CNT) field-effect transistor (FET) are studied. The CNT channel is so thin that there is no voltage drop perpendicular to the gate electrode plane, and this makes the device characteristics quite unique. The relation between the voltage and the electrochemical potentials, and the mass action law for electrons and holes are examined in the context of CNTs, and inversion and accumulation threshold voltages (V(sub Ti), and V(sub Ta)) are derived. V(sub Ti) of the CNTFETs has a much stronger doping dependence than that of the metal-oxide- semiconductor FETs, while V(sub Ta) of both devices depends weakly on doping with the same functional form.

2PI effective action for the SYK model and tensor field theories

NASA Astrophysics Data System (ADS)

Benedetti, Dario; Gurau, Razvan

2018-05-01

We discuss the two-particle irreducible (2PI) effective action for the SYK model and for tensor field theories. For the SYK model the 2PI effective action reproduces the bilocal reformulation of the model without using replicas. In general tensor field theories the 2PI formalism is the only way to obtain a bilocal reformulation of the theory, and as such is a precious instrument for the identification of soft modes and for possible holographic interpretations. We compute the 2PI action for several models, and push it up to fourth order in the 1 /N expansion for the model proposed by Witten in [1], uncovering a one-loop structure in terms of an auxiliary bilocal action.

Modeling the Value of Strategic Actions in the Superior Colliculus

PubMed Central

Thevarajah, Dhushan; Webb, Ryan; Ferrall, Christopher; Dorris, Michael C.

2009-01-01

In learning models of strategic game play, an agent constructs a valuation (action value) over possible future choices as a function of past actions and rewards. Choices are then stochastic functions of these action values. Our goal is to uncover a neural signal that correlates with the action value posited by behavioral learning models. We measured activity from neurons in the superior colliculus (SC), a midbrain region involved in planning saccadic eye movements, while monkeys performed two saccade tasks. In the strategic task, monkeys competed against a computer in a saccade version of the mixed-strategy game ”matching-pennies”. In the instructed task, saccades were elicited through explicit instruction rather than free choices. In both tasks neuronal activity and behavior were shaped by past actions and rewards with more recent events exerting a larger influence. Further, SC activity predicted upcoming choices during the strategic task and upcoming reaction times during the instructed task. Finally, we found that neuronal activity in both tasks correlated with an established learning model, the Experience Weighted Attraction model of action valuation (Camerer and Ho, 1999). Collectively, our results provide evidence that action values hypothesized by learning models are represented in the motor planning regions of the brain in a manner that could be used to select strategic actions. PMID:20161807

New 2D dilaton gravity for nonsingular black holes

NASA Astrophysics Data System (ADS)

Kunstatter, Gabor; Maeda, Hideki; Taves, Tim

2016-05-01

We construct a two-dimensional action that is an extension of spherically symmetric Einstein-Lanczos-Lovelock (ELL) gravity. The action contains arbitrary functions of the areal radius and the norm squared of its gradient, but the field equations are second order and obey Birkhoff’s theorem. In complete analogy with spherically symmetric ELL gravity, the field equations admit the generalized Misner-Sharp mass as the first integral that determines the form of the vacuum solution. The arbitrary functions in the action allow for vacuum solutions that describe a larger class of interesting nonsingular black hole spacetimes than previously available.

Models, Definitions, and Outcome Variables of Action Learning: A Synthesis with Implications for HRD

ERIC Educational Resources Information Center

Chenhall, Everon C.; Chermack, Thomas J.

2010-01-01

Purpose: The purpose of this paper is to propose an integrated model of action learning based on an examination of four reviewed action learning models, definitions, and espoused outcomes. Design/methodology/approach: A clear articulation of the strengths and limitations of each model was essential to developing an integrated model, which could be…

Fluctuations in Mass-Action Equilibrium of Protein Binding Networks

NASA Astrophysics Data System (ADS)

Yan, Koon-Kiu; Walker, Dylan; Maslov, Sergei

2008-12-01

We consider two types of fluctuations in the mass-action equilibrium in protein binding networks. The first type is driven by slow changes in total concentrations of interacting proteins. The second type (spontaneous) is caused by quickly decaying thermodynamic deviations away from equilibrium. We investigate the effects of network connectivity on fluctuations by comparing them to scenarios in which the interacting pair is isolated from the network and analytically derives bounds on fluctuations. Collective effects are shown to sometimes lead to large amplification of spontaneous fluctuations. The strength of both types of fluctuations is positively correlated with the complex connectivity and negatively correlated with complex concentration. Our general findings are illustrated using a curated network of protein interactions and multiprotein complexes in baker’s yeast, with empirical protein concentrations.

Depletion of Stercobilin in Fecal Matter from a Mouse Model of Autism Spectrum Disorders

PubMed Central

Sekera, Emily R.; Rudolph, Heather L.; Carro, Stephen D.; Morales, Michael J.; Bett, Glenna C. L.; Rasmusson, Randall L.; Wood, Troy D.

2017-01-01

Introduction Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders lacking a clinical biomarker for diagnosis. Emerging evidence shows that intestinal microflora from ASD subjects can be distinguished from controls, suggesting metabolite differences due to the action of intestinal microbes may provide a means for identifying potential biomarkers for ASD. Objectives The aim of this study was to determine if quantitative differences in levels of stercobilin and stercobilinogen, metabolites produced by biological action of intestinal microflora, exist in the fecal matter between an ASD mouse model population and controls. Methods Pairs of fecal samples were collected from two mouse groups, an ASD model group with Timothy syndrome 2 (TS2-NEO) and a gender-matched control group. After centrifugation, supernatant was spiked with an 18O-labeled stercobilin isotopomer and subjected to solid phase extraction for processing. Extracted samples were spotted on a stainless steel plate and subjected to matrix-assisted laser desorption and ionization mass spectrometry using dihydroxybenzoic acid as the matrix (n = 5). Peak areas for bilins and 18O-stercobilin isotopomers were determined in each fecal sample. Results A 40–45% depletion in stercobilin in TS2-NEO fecal samples compared with controls was observed with p < 0.05; a less dramatic depletion was observed for stercobilinogen. Conclusions The results show that stercobilin depletion in feces is observed for an ASD mouse model vs. controls. This may help to explain recent observations of a less diverse microbiome in humans with ASD and may prove helpful in developing a clinical ASD biomarker. PMID:29147105

Modeling Interdependent and Periodic Real-World Action Sequences

PubMed Central

Kurashima, Takeshi; Althoff, Tim; Leskovec, Jure

2018-01-01

Mobile health applications, including those that track activities such as exercise, sleep, and diet, are becoming widely used. Accurately predicting human actions in the real world is essential for targeted recommendations that could improve our health and for personalization of these applications. However, making such predictions is extremely difficult due to the complexities of human behavior, which consists of a large number of potential actions that vary over time, depend on each other, and are periodic. Previous work has not jointly modeled these dynamics and has largely focused on item consumption patterns instead of broader types of behaviors such as eating, commuting or exercising. In this work, we develop a novel statistical model, called TIPAS, for Time-varying, Interdependent, and Periodic Action Sequences. Our approach is based on personalized, multivariate temporal point processes that model time-varying action propensities through a mixture of Gaussian intensities. Our model captures short-term and long-term periodic interdependencies between actions through Hawkes process-based self-excitations. We evaluate our approach on two activity logging datasets comprising 12 million real-world actions (e.g., eating, sleep, and exercise) taken by 20 thousand users over 17 months. We demonstrate that our approach allows us to make successful predictions of future user actions and their timing. Specifically, TIPAS improves predictions of actions, and their timing, over existing methods across multiple datasets by up to 156%, and up to 37%, respectively. Performance improvements are particularly large for relatively rare and periodic actions such as walking and biking, improving over baselines by up to 256%. This demonstrates that explicit modeling of dependencies and periodicities in real-world behavior enables successful predictions of future actions, with implications for modeling human behavior, app personalization, and targeting of health interventions. PMID:29780977

Some results on excited hadrons in 2-flavor QCD

NASA Astrophysics Data System (ADS)

Engel, G.; Lang, C. B.; Limmer, M.; Mohler, D.; Schafer, A.

Results of hadron spectroscopy with two dynamical mass-degenerate chirally improved quarks are presented. Three ensembles with pion masses of 322(5), 470(4) and 525(7) MeV, lattices of size 16^3 \\times 32, and lattice spacings close to 0.15 fm are investigated. We discuss the possible appearance of scattering states, considering masses and eigenvectors. Partially quenched results in the scalar channel suggest the presence of a 2-particle state, however, in most channels we cannot identify them. Where available, we compare to results from quenched simulations using the same action.

Coral Reef Remote Sensing: Helping Managers Protect Reefs in a Changing Climate

NASA Astrophysics Data System (ADS)

Eakin, C.; Liu, G.; Li, J.; Muller-Karger, F. E.; Heron, S. F.; Gledhill, D. K.; Christensen, T.; Rauenzahn, J.; Morgan, J.; Parker, B. A.; Skirving, W. J.; Nim, C.; Burgess, T.; Strong, A. E.

2010-12-01

Climate change and ocean acidification are already having severe impacts on coral reef ecosystems. Warming oceans have caused corals to bleach, or expel their symbiotic algae (zooxanthellae) with alarming frequency and severity and have contributed to a rise in coral infectious diseases. Ocean acidification is reducing the availability of carbonate ions needed by corals and many other marine organisms to build structural components like skeletons and shells and may already be slowing the coral growth. These two impacts are already killing corals and slowing reef growth, reducing biodiversity and the structure needed to provide crucial ecosystem services. NOAA’s Coral Reef Watch (CRW) uses a combination of satellite data, in situ observations, and models to provide coral reef managers, scientists, and others with information needed to monitor threats to coral reefs. The advance notice provided by remote sensing and models allows resource managers to protect corals, coral reefs, and the services they provide, although managers often encounter barriers to implementation of adaptation strategies. This talk will focus on application of NOAA’s satellite and model-based tools that monitor the risk of mass coral bleaching on a global scale, ocean acidification in the Caribbean, and coral disease outbreaks in selected regions, as well as CRW work to train managers in their use, and barriers to taking action to adapt to climate change. As both anthropogenic CO2 and temperatures will continue to rise, local actions to protect reefs are becoming even more important.

Oral Supplementation with Beta-Hydroxy-Beta-Methylbutyrate, Arginine, and Glutamine Improves Lean Body Mass in Healthy Older Adults.

PubMed

Ellis, Amy C; Hunter, Gary R; Goss, Amy M; Gower, Barbara A

2018-04-19

Oral intake of beta-hydroxy-beta-methylbutyrate (HMB), arginine, and glutamine may ameliorate muscle loss by stimulating protein synthesis and decreasing protein degradation while simultaneously decreasing inflammation. Previous studies provide evidence for improvement in body composition with dietary supplementation of these ingredients among patients with muscle-wasting diseases. The objectives of this study were to examine the effects of this amino acid mixture on lean body mass, muscle volume, and physical function among healthy older adults. Thirty-one community-dwelling men and women, aged 65-89 years, were randomized to either two oral doses of the amino acid supplement (totaling 3 g HMB, 14 g arginine, 14 g glutamine) or placebo daily for six months. At baseline and month six, lean body mass was measured by air displacement plethysmography, dual-energy X-ray absorptiometry (DXA), and four-compartment model. Muscle volume of quadriceps was quantified by magnetic resonance imaging (MRI), and participants performed a battery of tests to assess physical function. As compared to the placebo group, the treatment group exhibited improvement in a timed stair climb (p =.016) as well as significant increases in lean body mass by all methods of assessment (p <.05). Regional analysis by DXA revealed increased arm lean mass in the supplement group only (p =.035). However, no change was observed in MRI-derived quadriceps volume. Dietary supplementation with HMB, arginine, and glutamine improved total body lean mass among a small sample of healthy older adults. Further research is indicated to elucidate mechanisms of action and to determine whether supplementation may benefit frail elders. Registered under ClinicalTrials.gov identifier no. NCT01057082.

Learning robot actions based on self-organising language memory.

PubMed

Wermter, Stefan; Elshaw, Mark

2003-01-01

In the MirrorBot project we examine perceptual processes using models of cortical assemblies and mirror neurons to explore the emergence of semantic representations of actions, percepts and concepts in a neural robot. The hypothesis under investigation is whether a neural model will produce a life-like perception system for actions. In this context we focus in this paper on how instructions for actions can be modeled in a self-organising memory. Current approaches for robot control often do not use language and ignore neural learning. However, our approach uses language instruction and draws from the concepts of regional distributed modularity, self-organisation and neural assemblies. We describe a self-organising model that clusters actions into different locations depending on the body part they are associated with. In particular, we use actual sensor readings from the MIRA robot to represent semantic features of the action verbs. Furthermore, we outline a hierarchical computational model for a self-organising robot action control system using language for instruction.

Archimedes' Principle in Action

ERIC Educational Resources Information Center

Kires, Marian

2007-01-01

The conceptual understanding of Archimedes' principle can be verified in experimental procedures which determine mass and density using a floating object. This is demonstrated by simple experiments using graduated beakers. (Contains 5 figures.)

Biotransformation of fluorophenyl pyridine carboxylic acids by the model fungus Cunninghamella elegans.

PubMed

Palmer-Brown, William; Dunne, Brian; Ortin, Yannick; Fox, Mark A; Sandford, Graham; Murphy, Cormac D

2017-09-01

1. Fluorine plays a key role in the design of new drugs and recent FDA approvals included two fluorinated drugs, tedizolid phosphate and vorapaxar, both of which contain the fluorophenyl pyridyl moiety. 2. To investigate the likely phase-I (oxidative) metabolic fate of this group, various fluorinated phenyl pyridine carboxylic acids were incubated with the fungus Cunninghamella elegans, which is an established model of mammalian drug metabolism. 3.  19 F NMR spectroscopy established the degree of biotransformation, which varied depending on the position of fluorine substitution, and gas chromatography-mass spectrometry (GC-MS) identified alcohols and hydroxylated carboxylic acids as metabolites. The hydroxylated metabolites were further structurally characterised by nuclear magnetic resonance spectroscopy (NMR), which demonstrated that hydroxylation occurred on the 4' position; fluorine in that position blocked the hydroxylation. 4. The fluorophenyl pyridine carboxylic acids were not biotransformed by rat liver microsomes and this was a consequence of inhibitory action, and thus, the fungal model was crucial in obtaining metabolites to establish the mechanism of catabolism.

Modelling the growth of plants with a uniform growth logistics.

PubMed

Kilian, H G; Bartkowiak, D; Kazda, M; Kaufmann, D

2014-05-21

The increment model has previously been used to describe the growth of plants in general. Here, we examine how the same logistics enables the development of different superstructures. Data from the literature are analyzed with the increment model. Increments are growth-invariant molecular clusters, treated as heuristic particles. This approach formulates the law of mass action for multi-component systems, describing the general properties of superstructures which are optimized via relaxation processes. The daily growth patterns of hypocotyls can be reproduced implying predetermined growth invariant model parameters. In various species, the coordinated formation and death of fine roots are modeled successfully. Their biphasic annual growth follows distinct morphological programs but both use the same logistics. In tropical forests, distributions of the diameter in breast height of trees of different species adhere to the same pattern. Beyond structural fluctuations, competition and cooperation within and between the species may drive optimization. All superstructures of plants examined so far could be reproduced with our approach. With genetically encoded growth-invariant model parameters (interaction with the environment included) perfect morphological development runs embedded in the uniform logistics of the increment model. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermodynamically Feasible Kinetic Models of Reaction Networks

PubMed Central

Ederer, Michael; Gilles, Ernst Dieter

2007-01-01

The dynamics of biological reaction networks are strongly constrained by thermodynamics. An holistic understanding of their behavior and regulation requires mathematical models that observe these constraints. However, kinetic models may easily violate the constraints imposed by the principle of detailed balance, if no special care is taken. Detailed balance demands that in thermodynamic equilibrium all fluxes vanish. We introduce a thermodynamic-kinetic modeling (TKM) formalism that adapts the concepts of potentials and forces from irreversible thermodynamics to kinetic modeling. In the proposed formalism, the thermokinetic potential of a compound is proportional to its concentration. The proportionality factor is a compound-specific parameter called capacity. The thermokinetic force of a reaction is a function of the potentials. Every reaction has a resistance that is the ratio of thermokinetic force and reaction rate. For mass-action type kinetics, the resistances are constant. Since it relies on the thermodynamic concept of potentials and forces, the TKM formalism structurally observes detailed balance for all values of capacities and resistances. Thus, it provides an easy way to formulate physically feasible, kinetic models of biological reaction networks. The TKM formalism is useful for modeling large biological networks that are subject to many detailed balance relations. PMID:17208985

Is DTPA a good competing chelating agent for Th(IV) in human serum and suitable in targeted alpha therapy?

PubMed

Le Du, Alicia; Sabatié-Gogova, Andrea; Morgenstern, Alfred; Montavon, Gilles

2012-04-01

The interaction between thorium and human serum components was studied using difference ultraviolet spectroscopy (DUS), ultrafiltration and high-pressure-anion exchange chromatography (HPAEC) with external inductively conducted plasma mass spectrometry (ICP-MS) analysis. Experimental data are compared with modelling results based on the law of mass action. Human serum transferrin (HSTF) interacts strongly with Th(IV), forming a ternary complex including two synergistic carbonate anions. This complex governs Th(IV) speciation under blood serum conditions. Considering the generally used Langmuir-type model, values of 10(33.5) and 10(32.5) were obtained for strong and weak sites, respectively. We showed that trace amounts of diethylene triamine pentaacetic acid (DTPA) cannot complex Th(IV) in the blood serum at equilibrium. Unexpectedly this effect is not related to the competition with HSTF but is due to the strong competition with major divalent metal ions for DTPA. However, Th-DTPA complex was shown to be stable for a few hours when it is formed before addition in the biological medium; this is related to the high kinetic stability of the complex. This makes DTPA a potential chelating agent for synthesis of (226)Th-labelled biomolecules for application in targeted alpha therapy. Copyright © 2011 Elsevier Inc. All rights reserved.

The message changes belief and the rest is theory: the "1% or less" milk campaign and reasoned action.

PubMed

Booth-Butterfield, Steve; Reger, Bill

2004-09-01

Theory-based approaches to public health interventions are useful for designing, implementing, and evaluating research. This paper describes and presents data to support the theoretical force behind the "1% or less" nutrition intervention studies. Using the Theory of Reasoned Action (TRA), high-fat (whole and 2%) milk users were targeted. Supermarket milk sale data were collected, and randomly selected intervention and comparison community residents were surveyed via telephone to assess milk use. TRA constructs were used in the surveys that were conducted immediately before and after a 6-week mass media campaign. Campaign messages were aimed at changing behavioral rather than normative beliefs. We found significant and predicted changes in intervention participants on intention, attitude, and behavioral beliefs, but not subjective norm outcomes. A path model showed support that TRA variables mediated significant changes in self-reported milk use. The analysis further validates the TRAs and supports a template using both the Principle of Compatibility and TRA to aid development and implementation of messages for effective behavior change field interventions.

Asymptotic safety of quantum gravity beyond Ricci scalars

NASA Astrophysics Data System (ADS)

Falls, Kevin; King, Callum R.; Litim, Daniel F.; Nikolakopoulos, Kostas; Rahmede, Christoph

2018-04-01

We investigate the asymptotic safety conjecture for quantum gravity including curvature invariants beyond Ricci scalars. Our strategy is put to work for families of gravitational actions which depend on functions of the Ricci scalar, the Ricci tensor, and products thereof. Combining functional renormalization with high order polynomial approximations and full numerical integration we derive the renormalization group flow for all couplings and analyse their fixed points, scaling exponents, and the fixed point effective action as a function of the background Ricci curvature. The theory is characterized by three relevant couplings. Higher-dimensional couplings show near-Gaussian scaling with increasing canonical mass dimension. We find that Ricci tensor invariants stabilize the UV fixed point and lead to a rapid convergence of polynomial approximations. We apply our results to models for cosmology and establish that the gravitational fixed point admits inflationary solutions. We also compare findings with those from f (R ) -type theories in the same approximation and pin-point the key new effects due to Ricci tensor interactions. Implications for the asymptotic safety conjecture of gravity are indicated.

Axial charges of N(1535) and N(1650) in lattice QCD with two flavors of dynamical quarks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Toru T.; Kunihiro, Teiji

2008-07-01

We show the first lattice QCD results on the axial charge g{sub A}{sup N}*{sup N}* of N*(1535) and N*(1650). The measurements are performed with two flavors of dynamical quarks employing the renormalization-group improved gauge action at {beta}=1.95 and the mean-field improved clover quark action with the hopping parameters, {kappa}=0.1375, 0.1390, and 0.1400. In order to properly separate signals of N*(1535) and N*(1650), we construct 2x2 correlation matrices and diagonalize them. Wraparound contributions in the correlator, which can be another source of signal contaminations, are eliminated by imposing the Dirichlet boundary condition in the temporal direction. We find that the axialmore » charge of N*(1535) takes small values such as g{sub A}{sup N}*{sup N}*{approx}O(0.1), whereas that of N*(1650) is about 0.5, which is found independent of quark masses and consistent with the predictions by the naive nonrelativistic quark model.« less

A knowledge-based approach to identification and adaptation in dynamical systems control

NASA Technical Reports Server (NTRS)

Glass, B. J.; Wong, C. M.

1988-01-01

Artificial intelligence techniques are applied to the problems of model form and parameter identification of large-scale dynamic systems. The object-oriented knowledge representation is discussed in the context of causal modeling and qualitative reasoning. Structured sets of rules are used for implementing qualitative component simulations, for catching qualitative discrepancies and quantitative bound violations, and for making reconfiguration and control decisions that affect the physical system. These decisions are executed by backward-chaining through a knowledge base of control action tasks. This approach was implemented for two examples: a triple quadrupole mass spectrometer and a two-phase thermal testbed. Results of tests with both of these systems demonstrate that the software replicates some or most of the functionality of a human operator, thereby reducing the need for a human-in-the-loop in the lower levels of control of these complex systems.

Pharmacological and toxicological assessment of innovative self-assembled polymeric micelles as powders for insulin pulmonary delivery.

PubMed

Andrade, Fernanda; Fonte, Pedro; Costa, Ana; Reis, Cassilda Cunha; Nunes, Rute; Almeida, Andreia; Ferreira, Domingos; Oliva, Mireia; Sarmento, Bruno

2016-09-01

Explore the use of polymeric micelles in the development of powders intended for pulmonary delivery of biopharmaceuticals, using insulin as a model protein. Formulations were assessed in vitro for aerosolization properties and in vivo for efficacy and safety using a streptozotocin-induced diabetic rat model. Powders presented good aerosolization properties like fine particle fraction superior to 40% and a mass median aerodynamic diameter inferior of 6 μm. Endotracheally instilled powders have shown a faster onset of action than subcutaneous administration of insulin at a dose of 10 IU/kg, with pharmacological availabilities up to 32.5% of those achieved by subcutaneous route. Additionally, micelles improved the hypoglycemic effect of insulin. Bronchoalveolar lavage screening for toxicity markers (e.g., lactate dehydrogenase, cytokines) revealed no signs of lung inflammation and cytotoxicity 14 days postadministration. Developed powders showed promising safety and efficacy characteristics for the systemic delivery of insulin by pulmonary administration.

Spontaneous breaking of scale invariance in a D = 3 U(N ) model with Chern-Simons gauge fields

DOE PAGES

Bardeen, William A.; Moshe, Moshe

2014-06-18

We study spontaneous breaking of scale invariance in the large N limit of three dimensional U(N ) κ Chern-Simons theories coupled to a scalar field in the fundamental representation. When a λ 6 ( Ø † · Ø) 3 self interaction term is added to the action we find a massive phase at a certain critical value for a combination of the λ(6) and ’t Hooft’s λ = N/κ couplings. This model attracted recent attention since at finite κ it contains a singlet sector which is conjectured to be dual to Vasiliev’s higher spin gravity on AdS 4. Our papermore » concentrates on the massive phase of the 3d boundary theory. We discuss the advantage of introducing masses in the boundary theory through spontaneous breaking of scale invariance.« less

The anti-tumor activity of a neutralizing nanobody targeting leptin receptor in a mouse model of melanoma.

PubMed

McMurphy, Travis; Xiao, Run; Magee, Daniel; Slater, Andrew; Zabeau, Lennart; Tavernier, Jan; Cao, Lei

2014-01-01

Environmental and genetic activation of a brain-adipocyte axis inhibits cancer progression. Leptin is the primary peripheral mediator of this anticancer effect in a mouse model of melanoma. In this study we assessed the effect of a leptin receptor antagonist on melanoma progression. Local administration of a neutralizing nanobody targeting the leptin receptor at low dose adjacent to tumor decreased tumor mass with no effects on body weight or food intake. In contrast, systemic administration of the nanobody failed to suppress tumor growth. Daily intraperitoneal injection of high-dose nanobody led to weight gain, hyperphagia, increased adiposity, hyperleptinemia, and hyperinsulinemia, and central effects mimicking leptin deficiency. The blockade of central actions of leptin by systemic delivery of nanobody may compromise its anticancer effect, underscoring the need to develop peripherally acting leptin antagonists coupled with efficient cancer-targeting delivery.

D Visualization for Virtual Museum Development

NASA Astrophysics Data System (ADS)

Skamantzari, M.; Georgopoulos, A.

2016-06-01

The interest in the development of virtual museums is nowadays rising rapidly. During the last decades there have been numerous efforts concerning the 3D digitization of cultural heritage and the development of virtual museums, digital libraries and serious games. The realistic result has always been the main concern and a real challenge when it comes to 3D modelling of monuments, artifacts and especially sculptures. This paper implements, investigates and evaluates the results of the photogrammetric methods and 3D surveys that were used for the development of a virtual museum. Moreover, the decisions, the actions, the methodology and the main elements that this kind of application should include and take into consideration are described and analysed. It is believed that the outcomes of this application will be useful to researchers who are planning to develop and further improve the attempts made on virtual museums and mass production of 3D models.

Reactive extraction of lactic acid with trioctylamine/methylene chloride/n-hexane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, D.H.; Hong, W.H.

The trioctylamine (TOA)/methylene chloride (MC)/n-hexane system was used as the extraction agent for the extraction of lactic acid. Curves of equilibrium and hydration were obtained at various temperatures and concentrations of TOA. A modified mass action model was proposed to interpret the equilibrium and the hydration curves. The reaction mechanism and the corresponding parameters which best represent the equilibrium data were estimated, and the concentration of water in the organic phase was predicted by inserting the parameters into the simple mathematical equation of the modified model. The concentration of MC and the change of temperature were important factors for themore » extraction and the stripping process. The stripping was performed by a simple distillation which was a combination of temperature-swing regeneration and diluent-swing regeneration. The type of inactive diluent has no influence on the stripping. The stripping efficiencies were about 70%.« less

A Brinkmanship Game Theory Model of Terrorism

NASA Astrophysics Data System (ADS)

Melese, Francois

This study reveals conditions under which a world leader might credibly issue a brinkmanship threat of preemptive action to deter sovereign states or transnational terrorist organizations from acquiring weapons of mass destruction (WMD). The model consists of two players: the United Nations (UN) “Principal,” and a terrorist organization “Agent.” The challenge in issuing a brinkmanship threat is that it needs to be sufficiently unpleasant to deter terrorists from acquiring WMD, while not being so repugnant to those that must carry it out that they would refuse to do so. Two “credibility constraints” are derived. The first relates to the unknown terrorist type (Hard or Soft), and the second to acceptable risks (“blowback”) to the World community. Graphing the incentive-compatible Nash equilibrium solutions reveals when a brinkmanship threat is credible, and when it is not - either too weak to be effective, or unacceptably dangerous to the World community.

Defining reactive sites on hydrated mineral surfaces: Rhombohedral carbonate minerals

NASA Astrophysics Data System (ADS)

Villegas-Jiménez, Adrián; Mucci, Alfonso; Pokrovsky, Oleg S.; Schott, Jacques

2009-08-01

Despite the success of surface complexation models (SCMs) to interpret the adsorptive properties of mineral surfaces, their construct is sometimes incompatible with fundamental chemical and/or physical constraints, and thus, casts doubts on the physical-chemical significance of the derived model parameters. In this paper, we address the definition of primary surface sites (i.e., adsorption units) at hydrated carbonate mineral surfaces and discuss its implications to the formulation and calibration of surface equilibria for these minerals. Given the abundance of experimental and theoretical information on the structural properties of the hydrated (10.4) cleavage calcite surface, this mineral was chosen for a detailed theoretical analysis of critical issues relevant to the definition of primary surface sites. Accordingly, a single, generic charge-neutral surface site ( tbnd CaCO 3·H 2O 0) is defined for this mineral whereupon mass-action expressions describing adsorption equilibria were formulated. The one-site scheme, analogous to previously postulated descriptions of metal oxide surfaces, allows for a simple, yet realistic, molecular representation of surface reactions and provides a generalized reference state suitable for the calculation of sorption equilibria for rhombohedral carbonate minerals via Law of Mass Action (LMA) and Gibbs Energy Minimization (GEM) approaches. The one-site scheme is extended to other rhombohedral carbonate minerals and tested against published experimental data for magnesite and dolomite in aqueous solutions. A simplified SCM based on this scheme can successfully reproduce surface charge, reasonably simulate the electrokinetic behavior of these minerals, and predict surface speciation agreeing with available spectroscopic data. According to this model, a truly amphoteric behavior is displayed by these surfaces across the pH scale but at circum-neutral pH (5.8-8.2) and relatively high ΣCO 2 (⩾1 mM), proton/bicarbonate co-adsorption becomes important and leads to the formation of a charge-neutral H 2CO 3-like surface species which may largely account for the surface charge-buffering behavior and the relatively wide range of pH values of isoelectric points (pH iep) reported in the literature for these minerals.

The Elementary Mass Action Rate Constants of P-gp Transport for a Confluent Monolayer of MDCKII-hMDR1 Cells

PubMed Central

Tran, Thuy Thanh; Mittal, Aditya; Aldinger, Tanya; Polli, Joseph W.; Ayrton, Andrew; Ellens, Harma; Bentz, Joe

2005-01-01

The human multi-drug resistance membrane transporter, P-glycoprotein, or P-gp, has been extensively studied due to its importance to human health and disease. Thus far, the kinetic analysis of P-gp transport has been limited to steady-state Michaelis-Menten approaches or to compartmental models, neither of which can prove molecular mechanisms. Determination of the elementary kinetic rate constants of transport will be essential to understanding how P-gp works. The experimental system we use is a confluent monolayer of MDCKII-hMDR1 cells that overexpress P-gp. It is a physiologically relevant model system, and transport is measured without biochemical manipulations of P-gp. The Michaelis-Menten mass action reaction is used to model P-gp transport. Without imposing the steady-state assumptions, this reaction depends upon several parameters that must be simultaneously fitted. An exhaustive fitting of transport data to find all possible parameter vectors that best fit the data was accomplished with a reasonable computation time using a hierarchical algorithm. For three P-gp substrates (amprenavir, loperamide, and quinidine), we have successfully fitted the elementary rate constants, i.e., drug association to P-gp from the apical membrane inner monolayer, drug dissociation back into the apical membrane inner monolayer, and drug efflux from P-gp into the apical chamber, as well as the density of efflux active P-gp. All three drugs had overlapping ranges for the efflux active P-gp, which was a benchmark for the validity of the fitting process. One novel finding was that the association to P-gp appears to be rate-limited solely by drug lateral diffusion within the inner monolayer of the plasma membrane for all three drugs. This would be expected if P-gp structure were open to the lipids of the apical membrane inner monolayer, as has been suggested by recent structural studies. The fitted kinetic parameters show how P-gp efflux of a wide range of xenobiotics has been maximized. PMID:15501934

Mass Fatality Planning and Religious Considerations Act

THOMAS, 112th Congress

Rep. Richardson, Laura [D-CA-37

2012-09-28

House - 10/11/2012 Referred to the Subcommittee on Emergency Preparedness, Response and Communications. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Action perception as hypothesis testing.

PubMed

Donnarumma, Francesco; Costantini, Marcello; Ambrosini, Ettore; Friston, Karl; Pezzulo, Giovanni

2017-04-01

We present a novel computational model that describes action perception as an active inferential process that combines motor prediction (the reuse of our own motor system to predict perceived movements) and hypothesis testing (the use of eye movements to disambiguate amongst hypotheses). The system uses a generative model of how (arm and hand) actions are performed to generate hypothesis-specific visual predictions, and directs saccades to the most informative places of the visual scene to test these predictions - and underlying hypotheses. We test the model using eye movement data from a human action observation study. In both the human study and our model, saccades are proactive whenever context affords accurate action prediction; but uncertainty induces a more reactive gaze strategy, via tracking the observed movements. Our model offers a novel perspective on action observation that highlights its active nature based on prediction dynamics and hypothesis testing. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Production in Pichia pastoris, antifungal activity and crystal structure of a class I chitinase from cowpea (Vigna unguiculata): Insights into sugar binding mode and hydrolytic action.

PubMed

Landim, Patrícia G Castro; Correia, Tuana O; Silva, Fredy D A; Nepomuceno, Denise R; Costa, Helen P S; Pereira, Humberto M; Lobo, Marina D P; Moreno, Frederico B M B; Brandão-Neto, José; Medeiros, Suelen C; Vasconcelos, Ilka M; Oliveira, José T A; Sousa, Bruno L; Barroso-Neto, Ito L; Freire, Valder N; Carvalho, Cristina P S; Monteiro-Moreira, Ana C O; Grangeiro, Thalles B

2017-04-01

A cowpea class I chitinase (VuChiI) was expressed in the methylotrophic yeast P. pastoris. The recombinant protein was secreted into the culture medium and purified by affinity chromatography on a chitin matrix. The purified chitinase migrated on SDS-polyacrylamide gel electrophoresis as two closely-related bands with apparent molecular masses of 34 and 37 kDa. The identity of these bands as VuChiI was demonstrated by mass spectrometry analysis of tryptic peptides and N-terminal amino acid sequencing. The recombinant chitinase was able to hydrolyze colloidal chitin but did not exhibit enzymatic activity toward synthetic substrates. The highest hydrolytic activity of the cowpea chitinase toward colloidal chitin was observed at pH 5.0. Furthermore, most VuChiI activity (approximately 92%) was retained after heating to 50 °C for 30 min, whereas treatment with 5 mM Cu 2+ caused a reduction of 67% in the enzyme's chitinolytic activity. The recombinant protein had antifungal activity as revealed by its ability to inhibit the spore germination and mycelial growth of Penicillium herquei. The three-dimensional structure of VuChiI was resolved at a resolution of 1.55 Å by molecular replacement. The refined model had 245 amino acid residues and 381 water molecules, and the final R-factor and R free values were 14.78 and 17.22%, respectively. The catalytic domain of VuChiI adopts an α-helix-rich fold, stabilized by 3 disulfide bridges and possessing a wide catalytic cleft. Analysis of the crystallographic model and molecular docking calculations using chito-oligosaccharides provided evidences about the VuChiI residues involved in sugar binding and catalysis, and a possible mechanism of antifungal action is suggested. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

Therapeutic actions of an insulin receptor activator and a novel peroxisome proliferator-activated receptor gamma agonist in the spontaneously hypertensive obese rat model of metabolic syndrome X.

PubMed

Velliquette, Rodney A; Friedman, Jacob E; Shao, J; Zhang, Bei B; Ernsberger, Paul

2005-07-01

Insulin resistance clusters with hyperlipidemia, impaired glucose tolerance, and hypertension as metabolic syndrome X. We tested a low molecular weight insulin receptor activator, demethylasterriquinone B-1 (DMAQ-B1), and a novel indole peroxisome proliferator-activated receptor gamma agonist, 2-(2-(4-phenoxy-2-propylphenoxy)ethyl)indole-5-acetic acid (PPEIA), in spontaneously hypertensive obese rats (SHROB), a genetic model of syndrome X. Agents were given orally for 19 days. SHROB showed fasting normoglycemia but impaired glucose tolerance after an oral load, as shown by increased glucose area under the curve (AUC) [20,700 mg x min/ml versus 8100 in lean spontaneously hypertensive rats (SHR)]. Insulin resistance was indicated by 20-fold excess fasting insulin and increased insulin AUC (6300 ng x min/ml versus 990 in SHR). DMAQ-B1 did not affect glucose tolerance (glucose AUC = 21,300) but reduced fasting insulin 2-fold and insulin AUC (insulin AUC = 4300). PPEIA normalized glucose tolerance (glucose AUC = 9100) and reduced insulin AUC (to 3180) without affecting fasting insulin. PPEIA also increased food intake, fat mass, and body weight gain (81 +/- 12 versus 45 +/- 8 g in untreated controls), whereas DMAQ-B1 had no effect on body weight but reduced subscapular fat mass. PPEIA but not DMAQ-B1 reduced blood pressure. In skeletal muscle, insulin-stimulated phosphorylation of the insulin receptor and insulin receptor substrate protein 1-associated phosphatidylinositol 3-kinase activity were decreased by 40 to 55% in SHROB relative to lean SHR. PPEIA, but not DMAQ-B1, enhanced both insulin actions. SHROB also showed severe hypertriglyceridemia (355 +/- 42 mg/dl versus 65 +/- 3 in SHR) attenuated by both agents (DMAQ-B1, 228 +/- 18; PPEIA, 79 +/- 3). Both these novel antidiabetic agents attenuate insulin resistance and hypertriglyceridemia associated with metabolic syndrome but via distinct mechanisms.

The minimalist grammar of action

PubMed Central

Pastra, Katerina; Aloimonos, Yiannis

2012-01-01

Language and action have been found to share a common neural basis and in particular a common ‘syntax’, an analogous hierarchical and compositional organization. While language structure analysis has led to the formulation of different grammatical formalisms and associated discriminative or generative computational models, the structure of action is still elusive and so are the related computational models. However, structuring action has important implications on action learning and generalization, in both human cognition research and computation. In this study, we present a biologically inspired generative grammar of action, which employs the structure-building operations and principles of Chomsky's Minimalist Programme as a reference model. In this grammar, action terminals combine hierarchically into temporal sequences of actions of increasing complexity; the actions are bound with the involved tools and affected objects and are governed by certain goals. We show, how the tool role and the affected-object role of an entity within an action drives the derivation of the action syntax in this grammar and controls recursion, merge and move, the latter being mechanisms that manifest themselves not only in human language, but in human action too. PMID:22106430

Effective vortex mass from microscopic theory

NASA Astrophysics Data System (ADS)

Han, Jung Hoon; Kim, June Seo; Kim, Min Jae; Ao, Ping

2005-03-01

We calculate the effective mass of a single quantized vortex in the Bardeen-Cooper-Schrieffer superconductor at finite temperature. Based on effective action approach, we arrive at the effective mass of a vortex as integral of the spectral function J(ω) divided by ω3 over frequency. The spectral function is given in terms of the quantum-mechanical transition elements of the gradient of the Hamiltonian between two Bogoliubov-deGennes (BdG) eigenstates. Based on self-consistent numerical diagonalization of the BdG equation we find that the effective mass per unit length of vortex at zero temperature is of order m(kfξ0)2 ( kf=Fermi momentum, ξ0=coherence length), essentially equaling the electron mass displaced within the coherence length from the vortex core. Transitions between the core states are responsible for most of the mass. The mass reaches a maximum value at T≈0.5Tc and decreases continuously to zero at Tc .

A continuous-time neural model for sequential action.

PubMed

Kachergis, George; Wyatte, Dean; O'Reilly, Randall C; de Kleijn, Roy; Hommel, Bernhard

2014-11-05

Action selection, planning and execution are continuous processes that evolve over time, responding to perceptual feedback as well as evolving top-down constraints. Existing models of routine sequential action (e.g. coffee- or pancake-making) generally fall into one of two classes: hierarchical models that include hand-built task representations, or heterarchical models that must learn to represent hierarchy via temporal context, but thus far lack goal-orientedness. We present a biologically motivated model of the latter class that, because it is situated in the Leabra neural architecture, affords an opportunity to include both unsupervised and goal-directed learning mechanisms. Moreover, we embed this neurocomputational model in the theoretical framework of the theory of event coding (TEC), which posits that actions and perceptions share a common representation with bidirectional associations between the two. Thus, in this view, not only does perception select actions (along with task context), but actions are also used to generate perceptions (i.e. intended effects). We propose a neural model that implements TEC to carry out sequential action control in hierarchically structured tasks such as coffee-making. Unlike traditional feedforward discrete-time neural network models, which use static percepts to generate static outputs, our biological model accepts continuous-time inputs and likewise generates non-stationary outputs, making short-timescale dynamic predictions. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Ultraperformance convergence chromatography-high resolution tandem mass spectrometry for lipid biomarker profiling and identification.

PubMed

Jones, Jace W; Carter, Claire L; Li, Fei; Yu, Jianshi; Pierzchalski, Keely; Jackson, Isabel L; Vujaskovic, Zeljko; Kane, Maureen A

2017-03-01

Lipids represent biologically ubiquitous and highly dynamic molecules in terms of abundance and structural diversity. Whereas the potential for lipids to inform on disease/injury is promising, their unique characteristics make detection and identification of lipids from biological samples analytically demanding. We report the use of ultraperformance convergence chromatography (UPC 2 ), a variant of supercritical fluid chromatography, coupled to high-resolution, data-independent tandem mass spectrometry for characterization of total lipid extracts from mouse lung tissue. The UPC 2 platform resulted in lipid class separation and when combined with orthogonal column chemistries yielded chromatographic separation of intra-class species based on acyl chain hydrophobicity. Moreover, the combined approach of using UPC 2 with orthogonal column chemistries, accurate mass measurements, time-aligned low- and high-collision energy total ion chromatograms, and positive and negative ion mode product ion spectra correlation allowed for confident lipid identification. Of great interest was the identification of differentially expressed ceramides that were elevated 24 h post whole thorax lung irradiation. The identification of lipids that were elevated 24 h post-irradiation signifies a unique opportunity to investigate early mechanisms of action prior to the onset of clinical symptoms in the whole thorax lung irradiation mouse model. Copyright © 2016 John Wiley & Sons, Ltd.

Reduced bone mass in obese young rats through PPAR omega suppression of wnt/beta-catenin signaling and direct action of free fatty acids (NEFA)

USDA-ARS?s Scientific Manuscript database

The relationship of obesity to skeletal development is unclear. We utilized total enteral nutrition to feed high and low fat diets (HFD and LFD) to rats for 4 wks to produce obesity. Weight gain was matched but fat mass, serum leptin and NEFA were increased by HFD (P < 0.05). HFD lowered total bone ...

Effect of molecular-mass characteristics of ethylene-propylene-diene monomer rubber on impact resistance and mobility of the melt of its modified blends with polypropylene

NASA Astrophysics Data System (ADS)

Ryzhikova, I. G.; Bauman, N. A.; Volkov, A. M.; Kazakov, Yu. M.; Volfson, S. I.

2014-05-01

The study concerned the effect of molecular-mass characteristics and Mooney viscosity of the initial EPDM rubber on the changes in the structure, impact strength and rheological properties of PP/EPDM blends as a result of their modification in a melt under the action of organic peroxide and peroxide-trimethylolpropane triacrylate (TMPTA) system.

Dismantling Terrorism: Developing Actionable Solutions for Today’s Plague of Violence

DTIC Science & Technology

2007-11-01

Press, 2006. Weapons of Mass Destruction Commission. Weapons of Terror: Freeing the World of Nuclear Biological and Chemical Arms, Stockholm, Sweden...Introduction to Weapons of Mass Destruction: Radioloqical, Chemical , and Biological. Hoboken: Wiley-Interscience, 2004. (U 793 .L36 2004) Martin, Gus, ed...electronic. Pita, Rene. "Assessing AI-Qaeda’s Chemical Threat." International Journal of Intelligence and Counterintelligence 20.3 (Fall 2007): 480

Evidence for soft bounds in Ubuntu package sizes and mammalian body masses

PubMed Central

Gherardi, Marco; Mandrà, Salvatore; Bassetti, Bruno; Cosentino Lagomarsino, Marco

2013-01-01

The development of a complex system depends on the self-coordinated action of a large number of agents, often determining unexpected global behavior. The case of software evolution has great practical importance: knowledge of what is to be considered atypical can guide developers in recognizing and reacting to abnormal behavior. Although the initial framework of a theory of software exists, the current theoretical achievements do not fully capture existing quantitative data or predict future trends. Here we show that two elementary laws describe the evolution of package sizes in a Linux-based operating system: first, relative changes in size follow a random walk with non-Gaussian jumps; second, each size change is bounded by a limit that is dependent on the starting size, an intriguing behavior that we call “soft bound.” Our approach is based on data analysis and on a simple theoretical model, which is able to reproduce empirical details without relying on any adjustable parameter and generates definite predictions. The same analysis allows us to formulate and support the hypothesis that a similar mechanism is shaping the distribution of mammalian body sizes, via size-dependent constraints during cladogenesis. Whereas generally accepted approaches struggle to reproduce the large-mass shoulder displayed by the distribution of extant mammalian species, this is a natural consequence of the softly bounded nature of the process. Additionally, the hypothesis that this model is valid has the relevant implication that, contrary to a common assumption, mammalian masses are still evolving, albeit very slowly. PMID:24324175

Magnetic field evolution in dwarf and Magellanic-type galaxies

NASA Astrophysics Data System (ADS)

Siejkowski, H.; Soida, M.; Chyży, K. T.

2018-03-01

Aims: Low-mass galaxies radio observations show in many cases surprisingly high levels of magnetic field. The mass and kinematics of such objects do not favour the development of effective large-scale dynamo action. We attempted to check if the cosmic-ray-driven dynamo can be responsible for measured magnetization in this class of poorly investigated objects. We investigated how starburst events on the whole, as well as when part of the galactic disk, influence the magnetic field evolution. Methods: We created a model of a dwarf/Magellanic-type galaxy described by gravitational potential constituted from two components: the stars and the dark-matter halo. The model is evolved by solving a three-dimensional (3D) magnetohydrodynamic equation with an additional cosmic-ray component, which is approximated as a fluid. The turbulence is generated in the system via supernova explosions manifested by the injection of cosmic-rays. Results: The cosmic-ray-driven dynamo works efficiently enough to amplify the magnetic field even in low-mass dwarf/Magellanic-type galaxies. The e-folding times of magnetic energy growth are 0.50 and 0.25 Gyr for the slow (50 km s-1) and fast (100 km s-1) rotators, respectively. The amplification is being suppressed as the system reaches the equipartition level between kinetic, magnetic, and cosmic-ray energies. An episode of star formation burst amplifies the magnetic field but only for a short time while increased star formation activity holds. We find that a substantial amount of gas is expelled from the galactic disk, and that the starburst events increase the efficiency of this process.

MASS MEDIA COMMUNICATION OF EMERGENCY ISSUES AND COUNTERMEASURES IN A NUCLEAR ACCIDENT: FUKUSHIMA REPORTING IN EUROPEAN NEWSPAPERS.

PubMed

Gallego, Eduardo; Cantone, Marie Claire; Oughton, Deborah H; Perko, Tanja; Prezelj, Iztok; Tomkiv, Yevgeniya

2017-04-01

This paper presents the results of a large study of 1340 articles published by two major newspapers in six European countries (Belgium, Italy, Norway, Slovenia, Spain and Russia) in the first 2 months after the Fukushima Daiichi nuclear disaster. The focus of the analysis is on the application and overall impact of protective actions, both during the emergency phase and later, how the newspapers describe those actions, which differences were apparent between countries and what recommendations can be extracted in order to improve general communication about these issues. A clear lesson is that, even under uncertainty and recognising limitations, responsible authorities need to provide transparent, clear and understandable information to the public and the mass media right from the beginning of the early phase of any nuclear emergency. Clear, concise messages should be given. Mass media could play a key role in reassuring the public if the countermeasures are clearly explained. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Decision making and action implementation: evidence for an early visually triggered motor activation specific to potential actions.

PubMed

Tandonnet, Christophe; Garry, Michael I; Summers, Jeffery J

2013-07-01

To make a decision may rely on accumulating evidence in favor of one alternative until a threshold is reached. Sequential-sampling models differ by the way of accumulating evidence and the link with action implementation. Here, we tested a model's prediction of an early action implementation specific to potential actions. We assessed the dynamics of action implementation in go/no-go and between-hand choice tasks by transcranial magnetic stimulation of the motor cortex (single- or paired-pulse TMS; 3-ms interstimulus interval). Prior to implementation of the selected action, the amplitude of the motor evoked potential first increased whatever the visual stimulus but only for the hand potentially involved in the to-be-produced action. These findings suggest that visual stimuli can trigger an early motor activation specific to potential actions, consistent with race-like models with continuous transmission between decision making and action implementation. Copyright © 2013 Society for Psychophysiological Research.

Long-Term Fish Oil Supplementation Induces Cardiac Electrical Remodeling by Changing Channel Protein Expression in the Rabbit Model

PubMed Central

Xu, Xulin; Jiang, Min; Wang, Yuhong; Smith, Timothy; Baumgarten, Clive M.; Wood, Mark A.; Tseng, Gea-Ny

2010-01-01

Clinical trials and epidemiological studies have suggested that dietary fish oil (FO) supplementation can provide an anti-arrhythmic benefit in some patient populations. The underlying mechanisms are not entirely clear. We wanted to understand how FO supplementation (for 4 weeks) affected the action potential configuration/duration of ventricular myocytes, and the ionic mechanism(s)/molecular basis for these effects. The experiments were conducted on adult rabbits, a widely used animal model for cardiac electrophysiology and pathophysiology. We used gas chromatography - mass spectroscopy to confirm that FO feeding produced a marked increase in the content of n-3 polyunsaturated fatty acids in the phospholipids of rabbit hearts. Left ventricular myocytes were used in current and voltage clamp experiments to monitor action potentials and ionic currents, respectively. Action potentials of myocytes from FO-fed rabbits exhibited much more positive plateau voltages and prolonged durations. These changes could be explained by an increase in the L-type Ca current (ICaL) and a decrease in the transient outward current (Ito) in these myocytes. FO feeding did not change the delayed rectifier or inward rectifier current. Immunoblot experiments showed that the FO-feeding induced changes in ICaL and Ito were associated with corresponding changes in the protein levels of major pore-forming subunits of these channels: increase in Cav1.2 and decrease in Kv4.2 and Kv1.4. There was no change in other channel subunits (Cav1.1, Kv4.3, KChIP2, and ERG1). We conclude that long-term fish oil supplementation can impact on cardiac electrical activity at least partially by changing channel subunit expression in cardiac myocytes. PMID:20405051

Detecting Deception in Movement: The Case of the Side-Step in Rugby

PubMed Central

Brault, Sébastien; Bideau, Benoit; Kulpa, Richard; Craig, Cathy M.

2012-01-01

Although coordinated patterns of body movement can be used to communicate action intention, they can also be used to deceive. Often known as deceptive movements, these unpredictable patterns of body movement can give a competitive advantage to an attacker when trying to outwit a defender. In this particular study, we immersed novice and expert rugby players in an interactive virtual rugby environment to understand how the dynamics of deceptive body movement influence a defending player’s decisions about how and when to act. When asked to judge final running direction, expert players who were found to tune into prospective tau-based information specified in the dynamics of ‘honest’ movement signals (Centre of Mass), performed significantly better than novices who tuned into the dynamics of ‘deceptive’ movement signals (upper trunk yaw and out-foot placement) (p<.001). These findings were further corroborated in a second experiment where players were able to move as if to intercept or ‘tackle’ the virtual attacker. An analysis of action responses showed that experts waited significantly longer before initiating movement (p<.001). By waiting longer and picking up more information that would inform about future running direction these experts made significantly fewer errors (p<.05). In this paper we not only present a mathematical model that describes how deception in body-based movement is detected, but we also show how perceptual expertise is manifested in action expertise. We conclude that being able to tune into the ‘honest’ information specifying true running action intention gives a strong competitive advantage. PMID:22701569

A Pharmacokinetics-Neural Mass Model (PK-NMM) for the Simulation of EEG Activity during Propofol Anesthesia

PubMed Central

Liang, Zhenhu; Duan, Xuejing; Su, Cui; Voss, Logan; Sleigh, Jamie; Li, Xiaoli

2015-01-01

Modeling the effects of anesthetic drugs on brain activity is very helpful in understanding anesthesia mechanisms. The aim of this study was to set up a combined model to relate actual drug levels to EEG dynamics and behavioral states during propofol-induced anesthesia. We proposed a new combined theoretical model based on a pharmacokinetics (PK) model and a neural mass model (NMM), which we termed PK-NMM—with the aim of simulating electroencephalogram (EEG) activity during propofol-induced general anesthesia. The PK model was used to derive propofol effect-site drug concentrations (C eff) based on the actual drug infusion regimen. The NMM model took C eff as the control parameter to produce simulated EEG-like (sEEG) data. For comparison, we used real prefrontal EEG (rEEG) data of nine volunteers undergoing propofol anesthesia from a previous experiment. To see how well the sEEG could describe the dynamic changes of neural activity during anesthesia, the rEEG data and the sEEG data were compared with respect to: power-frequency plots; nonlinear exponent (permutation entropy (PE)); and bispectral SynchFastSlow (SFS) parameters. We found that the PK-NMM model was able to reproduce anesthesia EEG-like signals based on the estimated drug concentration and patients’ condition. The frequency spectrum indicated that the frequency power peak of the sEEG moved towards the low frequency band as anesthesia deepened. Different anesthetic states could be differentiated by the PE index. The correlation coefficient of PE was 0.80±0.13 (mean±standard deviation) between rEEG and sEEG for all subjects. Additionally, SFS could track the depth of anesthesia and the SFS of rEEG and sEEG were highly correlated with a correlation coefficient of 0.77±0.13. The PK-NMM model could simulate EEG activity and might be a useful tool for understanding the action of propofol on brain activity. PMID:26720495

Action-based effects on music perception

PubMed Central

Maes, Pieter-Jan; Leman, Marc; Palmer, Caroline; Wanderley, Marcelo M.

2013-01-01

The classical, disembodied approach to music cognition conceptualizes action and perception as separate, peripheral processes. In contrast, embodied accounts of music cognition emphasize the central role of the close coupling of action and perception. It is a commonly established fact that perception spurs action tendencies. We present a theoretical framework that captures the ways in which the human motor system and its actions can reciprocally influence the perception of music. The cornerstone of this framework is the common coding theory, postulating a representational overlap in the brain between the planning, the execution, and the perception of movement. The integration of action and perception in so-called internal models is explained as a result of associative learning processes. Characteristic of internal models is that they allow intended or perceived sensory states to be transferred into corresponding motor commands (inverse modeling), and vice versa, to predict the sensory outcomes of planned actions (forward modeling). Embodied accounts typically refer to inverse modeling to explain action effects on music perception (Leman, 2007). We extend this account by pinpointing forward modeling as an alternative mechanism by which action can modulate perception. We provide an extensive overview of recent empirical evidence in support of this idea. Additionally, we demonstrate that motor dysfunctions can cause perceptual disabilities, supporting the main idea of the paper that the human motor system plays a functional role in auditory perception. The finding that music perception is shaped by the human motor system and its actions suggests that the musical mind is highly embodied. However, we advocate for a more radical approach to embodied (music) cognition in the sense that it needs to be considered as a dynamical process, in which aspects of action, perception, introspection, and social interaction are of crucial importance. PMID:24454299

Action-based effects on music perception.

PubMed

Maes, Pieter-Jan; Leman, Marc; Palmer, Caroline; Wanderley, Marcelo M

2014-01-03

The classical, disembodied approach to music cognition conceptualizes action and perception as separate, peripheral processes. In contrast, embodied accounts of music cognition emphasize the central role of the close coupling of action and perception. It is a commonly established fact that perception spurs action tendencies. We present a theoretical framework that captures the ways in which the human motor system and its actions can reciprocally influence the perception of music. The cornerstone of this framework is the common coding theory, postulating a representational overlap in the brain between the planning, the execution, and the perception of movement. The integration of action and perception in so-called internal models is explained as a result of associative learning processes. Characteristic of internal models is that they allow intended or perceived sensory states to be transferred into corresponding motor commands (inverse modeling), and vice versa, to predict the sensory outcomes of planned actions (forward modeling). Embodied accounts typically refer to inverse modeling to explain action effects on music perception (Leman, 2007). We extend this account by pinpointing forward modeling as an alternative mechanism by which action can modulate perception. We provide an extensive overview of recent empirical evidence in support of this idea. Additionally, we demonstrate that motor dysfunctions can cause perceptual disabilities, supporting the main idea of the paper that the human motor system plays a functional role in auditory perception. The finding that music perception is shaped by the human motor system and its actions suggests that the musical mind is highly embodied. However, we advocate for a more radical approach to embodied (music) cognition in the sense that it needs to be considered as a dynamical process, in which aspects of action, perception, introspection, and social interaction are of crucial importance.

Stability and Performance Metrics for Adaptive Flight Control

NASA Technical Reports Server (NTRS)

Stepanyan, Vahram; Krishnakumar, Kalmanje; Nguyen, Nhan; VanEykeren, Luarens

2009-01-01

This paper addresses the problem of verifying adaptive control techniques for enabling safe flight in the presence of adverse conditions. Since the adaptive systems are non-linear by design, the existing control verification metrics are not applicable to adaptive controllers. Moreover, these systems are in general highly uncertain. Hence, the system's characteristics cannot be evaluated by relying on the available dynamical models. This necessitates the development of control verification metrics based on the system's input-output information. For this point of view, a set of metrics is introduced that compares the uncertain aircraft's input-output behavior under the action of an adaptive controller to that of a closed-loop linear reference model to be followed by the aircraft. This reference model is constructed for each specific maneuver using the exact aerodynamic and mass properties of the aircraft to meet the stability and performance requirements commonly accepted in flight control. The proposed metrics are unified in the sense that they are model independent and not restricted to any specific adaptive control methods. As an example, we present simulation results for a wing damaged generic transport aircraft with several existing adaptive controllers.

Supersymmetric Dirac Born Infeld action with self-dual mass term

NASA Astrophysics Data System (ADS)

Nishino, Hitoshi; Rajpoot, Subhash; Reed, Kevin

2005-05-01

We introduce a Dirac Born Infeld action to a self-dual N = 1 supersymmetric vector multiplet in three dimensions. This action is based on the supersymmetric generalized self-duality in odd dimensions developed originally by Townsend, Pilch and van Nieuwenhuizen. Even though such a self-duality had been supposed to be very difficult to generalize to a supersymmetrically interacting system, we show that the Dirac Born Infeld action is actually compatible with supersymmetry and self-duality in three dimensions, even though the original self-duality receives corrections by the Dirac Born Infeld action. The interactions can be further generalized to arbitrary (non)polynomial interactions. As a by-product, we also show that a third-rank field strength leads to a more natural formulation of self-duality in 3D. We also show an interesting role played by the third-rank field strength leading to supersymmetry breaking, in addition to accommodating a Chern Simons form.

Uncertainty in action-value estimation affects both action choice and learning rate of the choice behaviors of rats

PubMed Central

Funamizu, Akihiro; Ito, Makoto; Doya, Kenji; Kanzaki, Ryohei; Takahashi, Hirokazu

2012-01-01

The estimation of reward outcomes for action candidates is essential for decision making. In this study, we examined whether and how the uncertainty in reward outcome estimation affects the action choice and learning rate. We designed a choice task in which rats selected either the left-poking or right-poking hole and received a reward of a food pellet stochastically. The reward probabilities of the left and right holes were chosen from six settings (high, 100% vs. 66%; mid, 66% vs. 33%; low, 33% vs. 0% for the left vs. right holes, and the opposites) in every 20–549 trials. We used Bayesian Q-learning models to estimate the time course of the probability distribution of action values and tested if they better explain the behaviors of rats than standard Q-learning models that estimate only the mean of action values. Model comparison by cross-validation revealed that a Bayesian Q-learning model with an asymmetric update for reward and non-reward outcomes fit the choice time course of the rats best. In the action-choice equation of the Bayesian Q-learning model, the estimated coefficient for the variance of action value was positive, meaning that rats were uncertainty seeking. Further analysis of the Bayesian Q-learning model suggested that the uncertainty facilitated the effective learning rate. These results suggest that the rats consider uncertainty in action-value estimation and that they have an uncertainty-seeking action policy and uncertainty-dependent modulation of the effective learning rate. PMID:22487046

Sphalerons in composite and nonstandard Higgs models

NASA Astrophysics Data System (ADS)

Spannowsky, Michael; Tamarit, Carlos

2017-01-01

After the discovery of the Higgs boson and the rather precise measurement of all electroweak boson's masses the local structure of the electroweak symmetry breaking potential is already quite well established. However, despite being a key ingredient to a fundamental understanding of the underlying mechanism of electroweak symmetry breaking, the global structure of the electroweak potential remains entirely unknown. The existence of sphalerons, unstable solutions of the classical action of motion that are interpolating between topologically distinct vacua, is a direct consequence of the Standard Model's SU (2 )L gauge group. Nevertheless, the sphaleron energy depends on the shape of the Higgs potential away from the minimum and can therefore be a litmus test for its global structure. Focusing on two scenarios, the minimal composite Higgs model SO (5 )/SO (4 ) or an elementary Higgs with a deformed electroweak potential, we calculate the change of the sphaleron energy compared to the Standard Model prediction. We find that the sphaleron energy would have to be measured to O (10 )% accuracy to exclude sizeable global deviations from the Standard Model Higgs potential. We further find that because of the periodicity of the scalar potential in composite Higgs models a second sphaleron branch with larger energy arises.

Dynamic modeling of nitrogen removal for a three-stage integrated fixed-film activated sludge process treating municipal wastewater.

PubMed

Moretti, Paul; Choubert, Jean-Marc; Canler, Jean-Pierre; Buffière, Pierre; Pétrimaux, Olivier; Lessard, Paul

2018-02-01

The integrated fixed-film activated sludge (IFAS) process is being increasingly used to enhance nitrogen removal for former activated sludge systems. The aim of this work is to evaluate a numerical model of a new nitrifying/denitrifying IFAS configuration. It consists of two carrier-free reactors (anoxic and aerobic) and one IFAS reactor with a filling ratio of 43% of carriers, followed by a clarifier. Simulations were carried out with GPS-X involving the nitrification reaction combined with a 1D heterogeneous biofilm model, including attachment/detachment processes. An original iterative calibration protocol was created comprising four steps and nine actions. Experimental campaigns were carried out to collect data on the pilot in operation, specifically for modelling purpose. The model used was able to predict properly the variations of the activated sludge (bulk) and the biofilm masses, the nitrification rates of both the activated sludge and the biofilm, and the nitrogen concentration in the effluent for short (4-10 days) and long (300 days) simulation runs. A calibrated parameter set is proposed (biokinetics, detachment, diffusion) related to the activated sludge, the biofilm and the effluent variables to enhance the model prediction on hourly and daily data sets.

Prediction of Metabolite Concentrations, Rate Constants and Post-Translational Regulation Using Maximum Entropy-Based Simulations with Application to Central Metabolism of Neurospora crassa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cannon, William; Zucker, Jeremy; Baxter, Douglas

We report the application of a recently proposed approach for modeling biological systems using a maximum entropy production rate principle in lieu of having in vivo rate constants. The method is applied in four steps: (1) a new ODE-based optimization approach based on Marcelin’s 1910 mass action equation is used to obtain the maximum entropy distribution, (2) the predicted metabolite concentrations are compared to those generally expected from experiment using a loss function from which post-translational regulation of enzymes is inferred, (3) the system is re-optimized with the inferred regulation from which rate constants are determined from the metabolite concentrationsmore » and reaction fluxes, and finally (4) a full ODE-based, mass action simulation with rate parameters and allosteric regulation is obtained. From the last step, the power characteristics and resistance of each reaction can be determined. The method is applied to the central metabolism of Neurospora crassa and the flow of material through the three competing pathways of upper glycolysis, the non-oxidative pentose phosphate pathway, and the oxidative pentose phosphate pathway are evaluated as a function of the NADP/NADPH ratio. It is predicted that regulation of phosphofructokinase (PFK) and flow through the pentose phosphate pathway are essential for preventing an extreme level of fructose 1, 6-bisphophate accumulation. Such an extreme level of fructose 1,6-bisphophate would otherwise result in a glassy cytoplasm with limited diffusion, dramatically decreasing the entropy and energy production rate and, consequently, biological competitiveness.« less

Forensic analysis of explosives using isotope ratio mass spectrometry (IRMS)--part 2: forensic inter-laboratory trial: bulk carbon and nitrogen stable isotopes in a range of chemical compounds (Australia and New Zealand).

PubMed

Benson, Sarah J; Lennard, Christopher J; Maynard, Philip; Hill, David M; Andrew, Anita S; Neal, Ken; Stuart-Williams, Hilary; Hope, Janet; Walker, G Stewart; Roux, Claude

2010-01-01

Comparability of data over time and between laboratories is a key issue for consideration in the development of global databases, and more broadly for quality assurance in general. One mechanism that can be utilized for evaluating traceability is an inter-laboratory trial. This paper addresses an inter-laboratory trial conducted across a number of Australian and New Zealand isotope ratio mass spectrometry (IRMS) laboratories. The main objective of this trial was to determine whether IRMS laboratories in these countries would record comparable values for the distributed samples. Four carbon containing and four nitrogen containing compounds were distributed to seven laboratories in Australia and one in New Zealand. The laboratories were requested to analyze the samples using their standard procedures. The data from each laboratory was evaluated collectively using International Standard ISO 13528 (Statistical methods for use in proficiency testing by inter-laboratory comparisons). "Warning signals" were raised against one participant in this trial. "Action signals" requiring corrective action were raised against four participants. These participants reviewed the data and possible sources for the discrepancies. This inter-laboratory trial was successful in providing an initial snapshot of the potential for traceability between the participating laboratories. The statistical methods described in this article could be used as a model for others needing to evaluate stable isotope results derived from multiple laboratories, e.g., inter-laboratory trials/proficiency testing. Ongoing trials will be conducted to improve traceability across the Australian and New Zealand IRMS community.

Leptin and its role in lipid metabolism.

PubMed

Hynes, G R; Jones, P J

2001-06-01

Since the discovery of leptin in 1994, a considerable amount of research has focused on leptin as a central regulator of body weight. In the animal model, research has demonstrated leptin action through hypothalamic centres altering both satiety and energy expenditure. In contrast to animal studies, it is unlikely that leptin functioning in the human system exerts such a profound role in body weight regulation. Human studies suggest that leptin levels are strongly correlated with both percentage fat mass and body mass index, in accordance with the proposed 'lipostatic theory'. Current research suggests the existence of a unique inter-relationship between dietary fat, leptin expression and leptin action within the peripheral system. More specifically, it has been demonstrated that polyunsaturated fatty acid (PUFA) intake influences adipose tissue expression of leptin, and of several lipogenic enzymes and transcription factors. In addition, leptin stimulates triglyceride depletion in white adipose tissue without increasing free fatty acid release, thus favouring fatty acids versus glucose as a fuel source. Recent studies suggest that the reduction in adipose hypertrophy observed with n-3 PUFA-containing fish oil feeding might involve a leptin-specific process. A large amount of evidence supports direct functioning of leptin in peripheral lipid metabolism in vivo and in vitro. It is possible that PUFAs will maintain an efficient level of circulating leptin, thus preventing leptin insensitivity and weight gain. There has been much recent progress in clinical leptin research, from energy expenditure to leptin analogue efficacy; the purpose of the present review is to summarize our current understanding of leptin functioning.

Associations between mass media exposure and birth preparedness among women in southwestern Uganda: a community-based survey.

PubMed

Asp, Gustav; Odberg Pettersson, Karen; Sandberg, Jacob; Kabakyenga, Jerome; Agardh, Anette

2014-01-01

Exposure to mass media provides increased awareness and knowledge, as well as changes in attitudes, social norms and behaviors that may lead to positive public health outcomes. Birth preparedness (i.e. the preparations for childbirth made by pregnant women, their families, and communities) increases the use of skilled birth attendants (SBAs) and hence reduces maternal morbidity and mortality. The aim of this study was to explore the association between media exposure and birth preparedness in rural Uganda. A total of 765 recently delivered women from 120 villages in the Mbarara District of southwest Uganda were selected for a community-based survey using two-stage cluster sampling. Univariate and multivariate logistic regression was performed with generalized linear mixed models using SPSS 21. We found that 88.6% of the women surveyed listened to the radio and 33.9% read newspapers. Birth preparedness actions included were money saved (87.8%), identified SBA (64.3%), identified transport (60.1%), and purchased childbirth materials (20.7%). Women who had taken three or more actions were coded as well birth prepared (53.9%). Women who read newspapers were more likely to be birth prepared (adjusted OR 2.2, 95% CI 1.5-3.2). High media exposure, i.e. regular exposure to radio, newspaper, or television, showed no significant association with birth preparedness (adjusted OR 1.3, 95% CI 0.9-2.0). Our results indicate that increased reading of newspapers can enhance birth preparedness and skilled birth attendance. Apart from general literacy skills, this requires newspapers to be accessible in terms of language, dissemination, and cost.

Modulation of muscle-tendon interaction in the human triceps surae during an energy dissipation task.

PubMed

Werkhausen, Amelie; Albracht, Kirsten; Cronin, Neil J; Meier, Rahel; Bojsen-Møller, Jens; Seynnes, Olivier R

2017-11-15

The compliance of elastic elements allows muscles to dissipate energy safely during eccentric contractions. This buffering function is well documented in animal models but our understanding of its mechanism in humans is confined to non-specific tasks, requiring a subsequent acceleration of the body. The present study aimed to examine the behaviour of the human triceps surae muscle-tendon unit (MTU) during a pure energy dissipation task, under two loading conditions. Thirty-nine subjects performed a single-leg landing task, with and without added mass. Ultrasound measurements were combined with three-dimensional kinematics and kinetics to determine instantaneous length changes of MTUs, muscle fascicles, Achilles tendon and combined elastic elements. Gastrocnemius and soleus MTUs lengthened during landing. After a small concentric action, fascicles contracted eccentrically during most of the task, whereas plantar flexor muscles were activated. Combined elastic elements lengthened until peak ankle moment and recoiled thereafter, whereas no recoil was observed for the Achilles tendon. Adding mass resulted in greater negative work and MTU lengthening, which were accompanied by a greater stretch of tendon and elastic elements and a greater recruitment of the soleus muscle, without any further fascicle strain. Hence, the buffering action of elastic elements delimits the maximal strain and lengthening velocity of active muscle fascicles and is commensurate with loading constraints. In the present task, energy dissipation was modulated via greater MTU excursion and more forceful eccentric contractions. The distinct strain pattern of the Achilles tendon supports the notion that different elastic elements may not systematically fulfil the same function. © 2017. Published by The Company of Biologists Ltd.

Baryon interactions from lattice QCD with physical quark masses - Nuclear forces and ΞΞ forces -

NASA Astrophysics Data System (ADS)

Doi, Takumi; Iritani, Takumi; Aoki, Sinya; Gongyo, Shinya; Hatsuda, Tetsuo; Ikeda, Yoichi; Inoue, Takashi; Ishii, Noriyoshi; Miyamoto, Takaya; Nemura, Hidekatsu; Sasaki, Kenji

2018-03-01

We present the latest lattice QCD results for baryon interactions obtained at nearly physical quark masses. Nf = 2 + 1 nonperturbatively O(a)-improved Wilson quark action with stout smearing and Iwasaki gauge action are employed on the lattice of (96a)4 ≃(8.1fm)4 with a-1 ≃2.3 GeV, where mπ ≃146 MeV and mK ≃525 MeV. In this report, we study the two-nucleon systems and two-Ξ systems in 1S0 channel and 3S1-3D1 coupled channel, and extract central and tensor interactions by the HAL QCD method. We also present the results for the NΩ interaction in 5S2 channel which is relevant to the NΩ pair-momentum correlation in heavy-ion collision experiments.

Creatine Supplementation and Skeletal Muscle Metabolism for Building Muscle Mass- Review of the Potential Mechanisms of Action.

PubMed

Farshidfar, Farnaz; Pinder, Mark A; Myrie, Semone B

2017-01-01

Creatine, a very popular supplement among athletic populations, is of growing interest for clinical applications. Since over 90% of creatine is stored in skeletal muscle, the effect of creatine supplementation on muscle metabolism is a widely studied area. While numerous studies over the past few decades have shown that creatine supplementation has many favorable effects on skeletal muscle physiology and metabolism, including enhancing muscle mass (growth/hypertrophy); the underlying mechanisms are poorly understood. This report reviews studies addressing the mechanisms of action of creatine supplementation on skeletal muscle growth/hypertrophy. Early research proposed that the osmotic effect of creatine supplementation serves as a cellular stressor (osmosensing) that acts as an anabolic stimulus for protein synthesis signal pathways. Other reports indicated that creatine directly affects muscle protein synthesis via modulations of components in the mammalian target of rapamycin (mTOR) pathway. Creatine may also directly affect the myogenic process (formation of muscle tissue), by altering secretions of myokines, such as myostatin and insulin-like growth factor-1, and expressions of myogenic regulatory factors, resulting in enhanced satellite cells mitotic activities and differentiation into myofiber. Overall, there is still no clear understanding of the mechanisms of action regarding how creatine affects muscle mass/growth, but current evidence suggests it may exert its effects through multiple approaches, with converging impacts on protein synthesis and myogenesis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A Survey of Parental Perception and Pattern of Action in Response to Influenza-like Illness in Their Children: Including Healthcare Use and Vaccination in Korea

PubMed Central

2017-01-01

Seasonal influenza is a significant cause of morbidity and mortality of children in Korea. However, few data are available on parental perception and action toward childhood influenza. This study aimed to characterize parental perception and patterns of action in response to influenza and influenza-like illnesses (ILIs), including vaccination and healthcare use. This prospective study involved a random survey of parents whose children were aged 6–59 months. The survey was conducted in October 2014. The study included 638 parents of 824 children younger than 6 years. Most parental information of influenza came from mass media (28.2%) and social media (15.5%). The factor that most often motivated parents to vaccinate their children against influenza was promotion of the government or mass media (36.6%). Negative predictors of immunization included safety concerns about influenza vaccination (28.1%) and mistrust in the vaccine's effectiveness (23.3%). Therefore, correct information about influenza and vaccination from mass media will be one of the cornerstones for implementing a successful childhood immunization program and reducing morbidity and mortality in Korea. Furthermore, to enroll younger children in vaccination programs, and to minimize coverage gaps, public concerns about vaccine safety should be resolved. The demographic data in the present study will be used to provide a deeper insight into a parental perception and will help health care providers increase influenza immunization rate. PMID:28049230

Analysis of a physics teacher's pedagogical `micro-actions' that support 17-year-olds' learning of free body diagrams via a modelling approach

NASA Astrophysics Data System (ADS)

Tay, Su Lynn; Yeo, Jennifer

2018-01-01

Great teaching is characterised by the specific actions a teacher takes in the classroom to bring about learning. In the context of model-based teaching (MBT), teachers' difficulty in working with students' models that are not scientifically consistent is troubling. To address this problem, the aim of this study is to identify the pedagogical micro-actions to support the development of scientific models and modelling skills during the evaluation and modification stages of MBT. Taking the perspective of pedagogical content knowing (PCKg), it identifies these micro-actions as an in-situ, dynamic transformation of knowledges of content, pedagogy, student and environment context. Through a case study approach, a lesson conducted by an experienced high-school physics teacher was examined. Audio and video recordings of the lesson contributed to the data sources. Taking a grounded approach in the analysis, eight pedagogical micro-actions enacted by the teacher were identified, namely 'clarification', 'evaluation', 'explanation', 'modification', 'exploration', 'referencing conventions', 'focusing' and 'meta-representing'. These micro-actions support students' learning related to the conceptual, cognitive, discursive and epistemological aspects of modelling. From the micro-actions, we identify the aspects of knowledges of PCKg that teachers need in order to competently select and enact these micro-actions. The in-situ and dynamic transformation of these knowledges implies that professional development should also be situated in the context in which these micro-actions are meaningful.

UV-Vis Action Spectroscopy Reveals a Conformational Collapse in Hydrogen-Rich Dinucleotide Cation Radicals.

PubMed

Korn, Joseph A; Urban, Jan; Dang, Andy; Nguyen, Huong T H; Tureček, František

2017-09-07

We report the generation of deoxyriboadenosine dinucleotide cation radicals by gas-phase electron transfer to dinucleotide dications and their noncovalent complexes with crown ether ligands. Stable dinucleotide cation radicals of a novel hydrogen-rich type were generated and characterized by tandem mass spectrometry and UV-vis photodissociation (UVPD) action spectroscopy. Electron structure theory analysis indicated that upon electron attachment the dinucleotide dications underwent a conformational collapse followed by intramolecular proton migrations between the nucleobases to give species whose calculated UV-vis absorption spectra matched the UVPD action spectra. Hydrogen-rich cation radicals generated from chimeric riboadenosine 5'-diesters gave UVPD action spectra that pointed to novel zwitterionic structures consisting of aromatic π-electron anion radicals intercalated between stacked positively charged adenine rings. Analogies with DNA ionization are discussed.

Quantum back-action-evading measurement of motion in a negative mass reference frame

NASA Astrophysics Data System (ADS)

Møller, Christoffer B.; Thomas, Rodrigo A.; Vasilakis, Georgios; Zeuthen, Emil; Tsaturyan, Yeghishe; Balabas, Mikhail; Jensen, Kasper; Schliesser, Albert; Hammerer, Klemens; Polzik, Eugene S.

2017-07-01

Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random quantum back-action (QBA) perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion. As a consequence of this randomness, and in accordance with the Heisenberg uncertainty principle, the QBA puts a limitation—the so-called standard quantum limit—on the precision of sensing of position, velocity and acceleration. Here we show that QBA on a macroscopic mechanical oscillator can be evaded if the measurement of motion is conducted in the reference frame of an atomic spin oscillator. The collective quantum measurement on this hybrid system of two distant and disparate oscillators is performed with light. The mechanical oscillator is a vibrational ‘drum’ mode of a millimetre-sized dielectric membrane, and the spin oscillator is an atomic ensemble in a magnetic field. The spin oriented along the field corresponds to an energetically inverted spin population and realizes a negative-effective-mass oscillator, while the opposite orientation corresponds to an oscillator with positive effective mass. The QBA is suppressed by -1.8 decibels in the negative-mass setting and enhanced by 2.4 decibels in the positive-mass case. This hybrid quantum system paves the way to entanglement generation and distant quantum communication between mechanical and spin systems and to sensing of force, motion and gravity beyond the standard quantum limit.

Nucleon structure in lattice QCD with dynamical domain-wall fermions quarks

NASA Astrophysics Data System (ADS)

Ohta, Shigemi

2006-12-01

We report RBC and RBC/UKQCD lattice QCD numerical calculations of nucleon electroweak matrix elements with dynamical domain-wall fermions (DWF) quarks. The first, RBC, set of dynamical DWF ensembles employs two degenerate flavors of DWF quarks and the DBW2 gauge action. Three sea quark mass values of 0.04, 0.03 and 0.02 in lattice units are used with about 200 gauge configurations each. The lattice cutoff is a-1 ˜ 1.7GeV and the spatial volume is about (1.9fm)3 . Despite the small volume, the ratio of the isovector vector and axial charges gA /gV and that of structure function moments x u-d / x u- d are in agreement with experiment, and show only very mild quark mass dependence. The second, RBC/UK, set of ensembles employs one strange and two degenerate (up and down) dynamical DWF quarks and Iwasaki gauge action. The strange quark mass is set at 0.04, and three up/down mass values of 0.03, 0.02 and 0.01 in lattice units are used. The lattice cutoff is a-1 ˜ 1.6GeV and the spatial volume is about (3.0fm)3 . Even with preliminary statistics of 25-30 gauge configurations, the ratios gA /gV and x u-d / x u- d are consistent with experiment and show only very mild quark mass dependence. Another structure function moment, d1 , though yet to be renormalized, appears small in both sets.

Oxytocin and bone

PubMed Central

Sun, Li; Zaidi, Mone; Zallone, Alberta

2014-01-01

One of the most meaningful results recently achieved in bone research has been to reveal that the pituitary hormones have profound effect on bone, so that the pituitary-bone axis has become one of the major topics in skeletal physiology. Here, we discuss the relevant evidence about the posterior pituitary hormone oxytocin (OT), previously thought to exclusively regulate parturition and breastfeeding, which has recently been established to directly regulate bone mass. Both osteoblasts and osteoclasts express OT receptors (OTR), whose stimulation enhances bone mass. Consistent with this, mice deficient in OT or OTR display profoundly impaired bone formation. In contrast, bone resorption remains unaffected in OT deficiency because, even while OT stimulates the genesis of osteoclasts, it inhibits their resorptive function. Furthermore, in addition to its origin from the pituitary, OT is also produced by bone marrow osteoblasts acting as paracrine-autocrine regulator of bone formation modulated by estrogens. In turn, the power of estrogen to increase bone mass is OTR-dependent. Therefore, OTR−/− mice injected with 17β-estradiol do not show any effects on bone formation parameters, while the same treatment increases bone mass in wild-type mice. These findings together provide evidence for an anabolic action of OT in regulating bone mass and suggest that bone marrow OT may enhance the bone-forming action of estrogen through an autocrine circuit. This established new physiological role for OT in the maintenance of skeletal integrity further suggests the potential use of this hormone for the treatment of osteoporosis. PMID:25209411

Quantum back-action-evading measurement of motion in a negative mass reference frame.

PubMed

Møller, Christoffer B; Thomas, Rodrigo A; Vasilakis, Georgios; Zeuthen, Emil; Tsaturyan, Yeghishe; Balabas, Mikhail; Jensen, Kasper; Schliesser, Albert; Hammerer, Klemens; Polzik, Eugene S

2017-07-12

Quantum mechanics dictates that a continuous measurement of the position of an object imposes a random quantum back-action (QBA) perturbation on its momentum. This randomness translates with time into position uncertainty, thus leading to the well known uncertainty on the measurement of motion. As a consequence of this randomness, and in accordance with the Heisenberg uncertainty principle, the QBA puts a limitation-the so-called standard quantum limit-on the precision of sensing of position, velocity and acceleration. Here we show that QBA on a macroscopic mechanical oscillator can be evaded if the measurement of motion is conducted in the reference frame of an atomic spin oscillator. The collective quantum measurement on this hybrid system of two distant and disparate oscillators is performed with light. The mechanical oscillator is a vibrational 'drum' mode of a millimetre-sized dielectric membrane, and the spin oscillator is an atomic ensemble in a magnetic field. The spin oriented along the field corresponds to an energetically inverted spin population and realizes a negative-effective-mass oscillator, while the opposite orientation corresponds to an oscillator with positive effective mass. The QBA is suppressed by -1.8 decibels in the negative-mass setting and enhanced by 2.4 decibels in the positive-mass case. This hybrid quantum system paves the way to entanglement generation and distant quantum communication between mechanical and spin systems and to sensing of force, motion and gravity beyond the standard quantum limit.

Toward an Integrative Social Identity Model of Collective Action: A Quantitative Research Synthesis of Three Socio-Psychological Perspectives

ERIC Educational Resources Information Center

van Zomeren, Martijn; Postmes, Tom; Spears, Russell

2008-01-01

An integrative social identity model of collective action (SIMCA) is developed that incorporates 3 socio-psychological perspectives on collective action. Three meta-analyses synthesized a total of 182 effects of perceived injustice, efficacy, and identity on collective action (corresponding to these socio-psychological perspectives). Results…

Biota Modeling in EPA's Preliminary Remediation Goal and Dose Compliance Concentration Calculators for Use in EPA Superfund Risk Assessment: Explanation of Intake Rate Derivation, Transfer Factor Compilation, and Mass Loading Factor Sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manning, Karessa L.; Dolislager, Fredrick G.; Bellamy, Michael B.

The Preliminary Remediation Goal (PRG) and Dose Compliance Concentration (DCC) calculators are screening level tools that set forth Environmental Protection Agency's (EPA) recommended approaches, based upon currently available information with respect to risk assessment, for response actions at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites, commonly known as Superfund. The screening levels derived by the PRG and DCC calculators are used to identify isotopes contributing the highest risk and dose as well as establish preliminary remediation goals. Each calculator has a residential gardening scenario and subsistence farmer exposure scenarios that require modeling of the transfer of contaminants frommore » soil and water into various types of biota (crops and animal products). New publications of human intake rates of biota; farm animal intakes of water, soil, and fodder; and soil to plant interactions require updates be implemented into the PRG and DCC exposure scenarios. Recent improvements have been made in the biota modeling for these calculators, including newly derived biota intake rates, more comprehensive soil mass loading factors (MLFs), and more comprehensive soil to tissue transfer factors (TFs) for animals and soil to plant transfer factors (BV's). New biota have been added in both the produce and animal products categories that greatly improve the accuracy and utility of the PRG and DCC calculators and encompass greater geographic diversity on a national and international scale.« less

Defective prolactin signaling impairs pancreatic β-cell development during the perinatal period

PubMed Central

Auffret, Julien; Freemark, Michael; Carré, Nadège; Mathieu, Yves; Tourrel-Cuzin, Cécile; Lombès, Marc; Movassat, Jamileh

2013-01-01

Prolactin (PRL) and placental lactogens stimulate β-cell replication and insulin production in pancreatic islets and insulinoma cells through binding to the PRL receptor (PRLR). However, the contribution of PRLR signaling to β-cell ontogeny and function in perinatal life and the effects of the lactogens on adaptive islet growth are poorly understood. We provide evidence that expansion of β-cell mass during both embryogenesis and the postnatal period is impaired in the PRLR−/− mouse model. PRLR−/− newborns display a 30% reduction of β-cell mass, consistent with reduced proliferation index at E18.5. PRL stimulates leucine incorporation and S6 kinase phosphorylation in INS-1 cells, supporting a role for β-cell mTOR signaling in PRL action. Interestingly, a defect in the development of acini is also observed in absence of PRLR signaling, with a sharp decline in cellular size in both endocrine and exocrine compartments. Of note, a decrease in levels of IGF-II, a PRL target, in the Goto-Kakizaki (GK) rat, a spontaneous model of type 2 diabetes, is associated with a lack of PRL-mediated β-cell proliferation in embryonic pancreatic buds. Reduced pancreatic IGF-II expression in both rat and mouse models suggests that this factor may constitute a molecular link between PRL signaling and cell ontogenesis. Together, these results provide evidence that PRL signaling is essential for pancreas ontogenesis during the critical perinatal window responsible for establishing functional β-cell reserve. PMID:24064341

The effect of personal and group discrimination on the subjective well-being of people with mental illness: the role of internalized stigma and collective action intention.

PubMed

Pérez-Garín, Daniel; Molero, Fernando; Bos, Arjan E R

2017-04-01

The goal of this study is to test a model in which personal discrimination predicts internalized stigma, while group discrimination predicts a greater willingness to engage in collective action. Internalized stigma and collective action, in turn, are associated to positive and negative affect. A cross-sectional study with 213 people with mental illness was conducted. The model was tested using path analysis. Although the data supported the model, its fit was not sufficiently good. A respecified model, in which a direct path from collective action to internalized stigma was added, showed a good fit. Personal and group discrimination appear to impact subjective well-being through two different paths: the internalization of stigma and collective action intentions, respectively. These two paths, however, are not completely independent, as collective action predicts a lower internalization of stigma. Thus, collective action appears as an important tool to reduce internalized stigma and improve subjective well-being. Future interventions to reduce the impact of stigma should fight the internalization of stigma and promote collective action are suggested.

The Role of Social Support and Self-efficacy for Planning Fruit and Vegetable Intake.

PubMed

Zhou, Guangyu; Gan, Yiqun; Hamilton, Kyra; Schwarzer, Ralf

2017-02-01

The aim of the current study was to examine the joint effect of self-efficacy, action planning, and received social support on fruit and vegetable intake. The study used a longitudinal design with 3 waves of data collection. Major university campus in Beijing, China. Young adults (n = 286). Age, gender, body mass index, dietary self-efficacy, and baseline behavior were measured at time 1. Two weeks after time 1, received social support and action planning were assessed (time 2); 4 weeks after time 1, subsequent fruit and vegetable consumption was measured (time 3). In a path analysis, action planning at time 2 was specified as a mediator between self-efficacy at time 1 and fruit and vegetable intake at time 3, controlling for age, gender, body mass index, and baseline behavior. In addition, in a conditional process analysis, received social support at time 2 was specified as a moderator of the self-efficacy-planning relationship. Action planning mediated between self-efficacy and subsequent dietary behavior, and received social support moderated between self-efficacy and planning supporting a compensation effect. Action planning served as a proximal predictor of fruit and vegetable intake, and planning one's consumption was facilitated by dietary self-efficacy. Through the identification of social cognitive factors influencing dietary planning, interventions can target self-efficacy and received social support to test the efficacy of these mechanisms in increasing individuals' ability to ensure they consume adequate amounts of fruits and vegetables. Copyright © 2016 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

Precision Higgs Physics, Effective Field Theory, and Dark Matter

NASA Astrophysics Data System (ADS)

Henning, Brian Quinn

The recent discovery of the Higgs boson calls for detailed studies of its properties. As precision measurements are indirect probes of new physics, the appropriate theoretical framework is effective field theory. In the first part of this thesis, we present a practical three-step procedure of using the Standard Model effective field theory (SM EFT) to connect ultraviolet (UV) models of new physics with weak scale precision observables. With this procedure, one can interpret precision measurements as constraints on the UV model concerned. We give a detailed explanation for calculating the effective action up to one-loop order in a manifestly gauge covariant fashion. The covariant derivative expansion dramatically simplifies the process of matching a UV model with the SM EFT, and also makes available a universal formalism that is easy to use for a variety of UV models. A few general aspects of renormalization group running effects and choosing operator bases are discussed. Finally, we provide mapping results between the bosonic sector of the SM EFT and a complete set of precision electroweak and Higgs observables to which present and near future experiments are sensitive. With a detailed understanding of how to use the SM EFT, we then turn to applications and study in detail two well-motivated test cases. The first is singlet scalar field that enables the first-order electroweak phase transition for baryogenesis; the second example is due to scalar tops in the MSSM. We find both Higgs and electroweak measurements are sensitive probes of these cases. The second part of this thesis centers around dark matter, and consists of two studies. In the first, we examine the effects of relic dark matter annihilations on big bang nucleosynthesis (BBN). The magnitude of these effects scale simply with the dark matter mass and annihilation cross-section, which we derive. Estimates based on these scaling behaviors indicate that BBN severely constrains hadronic and radiative dark matter annihilation channels in the previously unconsidered dark matter mass region MeV <˜ m x <˜ 10 GeV. Interestingly, we find that BBN constraints on hadronic annihilation channels are competitive with similar bounds derived from the cosmic microwave background. Our second study of dark matter concerns a possible connection with supersymmetry and the keV scale. Various theoretical and experimental considerations motivate models with high scale supersymmetry breaking. While such models may be difficult to test in colliders, we propose looking for signatures at much lower energies. We show that a keV line in the X-ray spectrum of galaxy clusters (such as the recently disputed 3.5 keV observation) can have its origin in a universal string axion coupled to a hidden supersymmetry breaking sector. A linear combination of the string axion and an additional axion in the hidden sector remains light, obtaining a mass of order 10 keV through supersymmetry breaking dynamics. In order to explain the X-ray line, the scale of supersymmetry breaking must be about 1011-12 GeV. This motivates high scale supersymmetry as in pure gravity mediation or minimal split supersymmetry and is consistent with all current limits. Since the axion mass is controlled by a dynamical mass scale, this mass can be much higher during inflation, avoiding isocurvature (and domain wall) problems associated with high scale inflation. In an appendix E we present a mechanism for dilaton stabilization that additionally leads to O(1) modifications of the gaugino mass from anomaly mediation.

Three-dimensional simulation of the motion of a single particle under a simulated turbulent velocity field

NASA Astrophysics Data System (ADS)

Moreno-Casas, P. A.; Bombardelli, F. A.

2015-12-01

A 3D Lagrangian particle tracking model is coupled to a 3D channel velocity field to simulate the saltation motion of a single sediment particle moving in saltation mode. The turbulent field is a high-resolution three dimensional velocity field that reproduces a by-pass transition to turbulence on a flat plate due to free-stream turbulence passing above de plate. In order to reduce computational costs, a decoupled approached is used, i.e., the turbulent flow is simulated independently from the tracking model, and then used to feed the 3D Lagrangian particle model. The simulations are carried using the point-particle approach. The particle tracking model contains three sub-models, namely, particle free-flight, a post-collision velocity and bed representation sub-models. The free-flight sub-model considers the action of the following forces: submerged weight, non-linear drag, lift, virtual mass, Magnus and Basset forces. The model also includes the effect of particle angular velocity. The post-collision velocities are obtained by applying conservation of angular and linear momentum. The complete model was validated with experimental results from literature within the sand range. Results for particle velocity time series and distribution of particle turbulent intensities are presented.

A research on the postural stability of a person wearing the lower limb exoskeletal robot by the HAT model.

PubMed

Chang, Minsu; Kim, Yeongmin; Lee, Yoseph; Jeon, Doyoung

2017-07-01

This paper proposes a method of detecting the postural stability of a person wearing the lower limb exoskeletal robot with the HAT(Head-Arm-Trunk) model. Previous studies have shown that the human posture is stable when the CoM(Center of Mass) of the human body is placed on the BoS(Base of Support). In the case of the lower limb exoskeletal robot, the motion data, which are used for the CoM estimation, are acquired by sensors in the robot. The upper body, however, does not have sensors in each segment so that it may cause the error of the CoM estimation. In this paper, the HAT(Head-Arm-Trunk) model which combines head, arms, and torso into a single segment is considered because the motion of head and arms are unknown due to the lack of sensors. To verify the feasibility of HAT model, the reflecting markers are attached to each segment of the whole human body and the exact motion data are acquired by the VICON to compare the COM of the full body model and HAT model. The difference between the CoM with full body and that with HAT model is within 20mm for the various motions of head and arms. Based on the HAT model, the XCoM(Extrapolated Center of Mass) which includes the velocity of the CoM is used for prediction of the postural stability. The experiment of making unstable posture shows that the XCoM of the whole body based on the HAT model is feasible to detect the instance of postural instability earlier than the CoM by 20-250 msec. This result may be used for the lower limb exoskeletal robot to prepare for any action to prevent the falling down.

Structural Characterization of Laboratory Made Tholins by IRMPD Action Spectroscopy and Ultrahigh Resolution Mass Spectrometry

NASA Astrophysics Data System (ADS)

Thissen, R.; Somogyi, A.; Vuitton, V.; Bégué, D.; Lemaire, J.; Steinmetz, V.

2011-10-01

The complex organic material that is found on the surface and within the haze layer of Titan is attributed to chemistry occurring in its thick N2/CH4 atmosphere. Although several groups are producing in various laboratory setting the socalled tholins which have been investigated by using analytical methods including UV/Vis, fluorescence, IR, and MS1-5, these very complex organic mixtures still hold many unanswered questions, especially related to the potentiality for their prebiotic chemistry. In addition to tholins characterization and analysis, we recently investigated quantitatively the hydrolysis kinetics of tholins in pure and NH3 containing water at different temperatures.7-8 Our groups at UJF (Grenoble) and at U of Arizona (Tucson) have been collaborating on mass spectral analyses of tholins samples for several years.9 Here, we report our most recent results on the structural characterization of tholins by infrared multiphoton dissociation (IRMPD) action spectroscopy10 and ultrahigh resolution MS. IRMPD action spectroscopy is a recently developed technique that uses IR photons of variable wavelengths to activate ions trapped inside an ion trap. When photons are absorbed at a given wavelength, the selected ion fragments and this fragmentation is monitored as a function of wavelength, analog to an absorption spectrum (impossible to record otherwise because of the much reduced density). This technique can, therefore, be used to determine IR spectra of ions in the gas phase, and provides with very acute structural information. IRMPD action spectroscopy is often used to distinguish between structural isomers of isobaric ions. The drawback is that it requests for high power lasers. Only two Free Electron Lasers (FEL) are available in the world and allow to record spectra with reasonable resolution (20-25 cm-1). IRMPD action spectra of selected ions from tholins will be presented and discussed together with observed fragmentation processes that reveal structural features of the ions. We have studied ions in the mass range from 60 to 160 u, corresponding to particularly interesting species already characterized by other (e.g. tandem MS/MS) methods.

Do metric fluctuations affect the Higgs dynamics during inflation?

NASA Astrophysics Data System (ADS)

Markkanen, Tommi; Nurmi, Sami; Rajantie, Arttu

2017-12-01

We show that the dynamics of the Higgs field during inflation is not affected by metric fluctuations if the Higgs is an energetically subdominant light spectator. For Standard Model parameters we find that couplings between Higgs and metric fluctuations are suppressed by Script O(10‑7). They are negligible compared to both pure Higgs terms in the effective potential and the unavoidable non-minimal Higgs coupling to background scalar curvature. The question of the electroweak vacuum instability during high energy scale inflation can therefore be studied consistently using the Jordan frame action in a Friedmann-Lemaître-Robertson-Walker metric, where the Higgs-curvature coupling enters as an effective mass contribution. Similar results apply for other light spectator scalar fields during inflation.

Quintessence from virtual dark matter

NASA Astrophysics Data System (ADS)

Damdinsuren, Battsetseg; Sim, Jonghyun; Lee, Tae Hoon

2017-09-01

Considering a theory of Brans-Dicke gravity with general couplings of Higgs-like bosons including a non-renormalizable term, we derive the low-energy effective theory action in the Universe of a temperature much lower than the Higgs-like boson mass. Necessary equations containing gravitational field equations and an effective potential of the Brans-Dicke scalar field are obtained, which are induced through virtual interactions of the Higgs-like heavy field in the late-time Universe. We find a de Sitter cosmological solution with the inverse power law effective potential of the scalar field and discuss the possibility that the late-time acceleration of our Universe can be naturally explained by means of the solution. We also investigate stability properties of the quintessence model by using a linear approximation.

Critical gravity in four dimensions.

PubMed

Lü, H; Pope, C N

2011-05-06

We study four-dimensional gravity theories that are rendered renormalizable by the inclusion of curvature-squared terms to the usual Einstein action with a cosmological constant. By choosing the parameters appropriately, the massive scalar mode can be eliminated and the massive spin-2 mode can become massless. This "critical" theory may be viewed as a four-dimensional analogue of chiral topologically massive gravity, or of critical "new massive gravity" with a cosmological constant, in three dimensions. We find that the on-shell energy for the remaining massless gravitons vanishes. There are also logarithmic spin-2 modes, which have positive energy. The mass and entropy of standard Schwarzschild-type black holes vanish. The critical theory might provide a consistent toy model for quantum gravity in four dimensions.

Contribution of the six major gait determinants on the vertical center of mass trajectory and the vertical ground reaction force.

PubMed

Hayot, C; Sakka, S; Lacouture, P

2013-04-01

Saunders et al. (1953) stated that the introduction of six gait determinants (pelvic rotation, pelvic obliquity, stance knee flexion, foot and ankle mechanisms, and tibiofemoral angle) to a compass gait model (two rigid legs hinged at the hips) provides an accurate simulation of the actual trajectory of the whole body center of mass (CoM). Their respective actions could also explain the shape of the vertical ground reaction force (GRF) pattern. Saunders' approach is considered as a kinematic description of some features of gait and is subject to debate. The purpose of this study is to realize a rigorous mechanical evaluation of the gait determinants theory using an appropriated mathematical model in which specific experimental data of gait trials are introduced. We first simulate a compass-like CoM trajectory using the proposed 3D mathematical model. Then, factorizing the model to introduce successively the kinematic data related to each gait determinant, we assess their respective contribution to both the CoM trajectory and the pattern of vertical GRF at different gait speeds. The results show that the stance knee flexion significatively decreases the estimated position of the CoM during midstance. Stance knee extension and pelvic obliquity contribute to the appearance of the pattern of vertical GRF during stance. The stance ankle dorsiflexion significatively contributes to CoM vertical excursion and the ankle plantarflexion contributes to the vertical GRF during terminal stance. The largest contribution towards the minimization of the CoM vertical amplitude during the complete gait step appears when considering the foot mechanisms and the pelvic obliquity in the proposed model. Copyright © 2012 Elsevier B.V. All rights reserved.

Sex steroids during bone growth: a comparative study between mouse models for hypogonadal and senile osteoporosis.

PubMed

Ophoff, J; Venken, K; Callewaert, F; Boonen, S; Bouillon, R; Vanderschueren, D

2009-10-01

In this study, the role of disturbed bone mineral acquisition during puberty in the pathogenesis of osteoporosis was studied. To this end, a mouse model for senile and hypogonadal osteoporosis was used. Longitudinal follow-up showed that bone fragility in both models results from deficient bone build-up during early puberty. Male osteoporosis may result from impaired bone growth. This study characterizes the mechanisms of deficient peak bone mass acquisition in models for senile (SAMP6) and hypogonadal (orchidectomized SAMR1) osteoporosis. Bone mineral acquisition was investigated longitudinally in SAMP6 and orchidectomized SAMR1 mice (eight to ten animals per group) using peripheral quantitative computed tomography and histomorphometry. Additionally, the effects of long-term 5alpha-dihydrotestosterone (DHT) and 17beta-estradiol (E2) replacement were studied. Statistical analysis was performed using ANOVA and Student's t test. SAMP6 mice showed an early (4 weeks) medullary expansion of the cortex due to impaired endocortical bone formation (-43%). Despite compensatory periosteal bone formation (+47%), cortical thickness was severely reduced in 20-week-old SAMP6 versus SAMR1. Orchidectomy reduced periosteal apposition between 4 and 8 weeks of age and resulted in high bone turnover and less trabecular bone gain in SAMP6 and SAMR1. DHT and E2 stimulated periosteal expansion and trabecular bone in orchidectomized SAMP6 and SAMR1. E2 stimulated endocortical apposition in SAMP6. Moreover, sex steroid action occurred between 4 and 8 weeks of age. Bone fragility in both models resulted from deficient bone build-up during early puberty. DHT and E2 improved bone mass acquisition in orchidectomized animals, suggesting a role for AR and ER in male skeletal development.

Models of morality

PubMed Central

Crockett, Molly J.

2013-01-01

Moral dilemmas engender conflicts between two traditions: consequentialism, which evaluates actions based on their outcomes, and deontology, which evaluates actions themselves. These strikingly resemble two distinct decision-making architectures: a model-based system that selects actions based on inferences about their consequences; and a model-free system that selects actions based on their reinforcement history. Here, I consider how these systems, along with a Pavlovian system that responds reflexively to rewards and punishments, can illuminate puzzles in moral psychology. PMID:23845564

Quark masses and strong coupling constant in 2+1 flavor QCD

DOE PAGES

Maezawa, Y.; Petreczky, P.

2016-08-30

We present a determination of the strange, charm and bottom quark masses as well as the strong coupling constant in 2+1 flavor lattice QCD simulations using highly improved staggered quark action. The ratios of the charm quark mass to the strange quark mass and the bottom quark mass to the charm quark mass are obtained from the meson masses calculated on the lattice and found to be mc/ms = 11.877(91) and mb/mc = 4.528(57) in the continuum limit. We also determine the strong coupling constant and the charm quark mass using the moments of pseudoscalar charmonium correlators: α s(μ =more » m c) = 0.3697(85) and mc(μ = mc) = 1.267(12) GeV. Our result for αs corresponds to the determination of the strong coupling constant at the lowest energy scale so far and is translated to the value α s(μ = M Z, n f = 5) = 0.11622(84).« less

A framework for the use of agent based modeling to simulate ...

EPA Pesticide Factsheets

Simulation of human behavior in exposure modeling is a complex task. Traditionally, inter-individual variation in human activity has been modeled by drawing from a pool of single day time-activity diaries such as the US EPA Consolidated Human Activity Database (CHAD). Here, an agent-based model (ABM) is used to simulate population distributions of longitudinal patterns of four macro activities (sleeping, eating, working, and commuting) in populations of adults over a period of one year. In this ABM, an individual is modeled as an agent whose movement through time and space is determined by a set of decision rules. The rules are based on the agent having time-varying “needs” that are satisfied by performing actions. Needs are modeled as increasing over time, and taking an action reduces the need. Need-satisfying actions include sleeping (meeting the need for rest), eating (meeting the need for food), and commuting/working (meeting the need for income). Every time an action is completed, the model determines the next action the agent will take based on the magnitude of each of the agent’s needs at that point in time. Different activities advertise their ability to satisfy various needs of the agent (such as food to eat or sleeping in a bed or on a couch). The model then chooses the activity that satisfies the greatest of the agent’s needs. When multiple actions could address a need, the model will choose the most effective of the actions (bed over the couc

Altered Connectivity and Action Model Formation in Autism Is Autism

PubMed Central

Mostofsky, Stewart H.; Ewen, Joshua B.

2014-01-01

Internal action models refer to sensory-motor programs that form the brain basis for a wide range of skilled behavior and for understanding others’ actions. Development of these action models, particularly those reliant on visual cues from the external world, depends on connectivity between distant brain regions. Studies of children with autism reveal anomalous patterns of motor learning and impaired execution of skilled motor gestures. These findings robustly correlate with measures of social and communicative function, suggesting that anomalous action model formation may contribute to impaired development of social and communicative (as well as motor) capacity in autism. Examination of the pattern of behavioral findings, as well as convergent data from neuroimaging techniques, further suggests that autism-associated action model formation may be related to abnormalities in neural connectivity, particularly decreased function of long-range connections. This line of study can lead to important advances in understanding the neural basis of autism and, more critically, can be used to guide effective therapies targeted at improving social, communicative, and motor function. PMID:21467306

Development of an in vitro Hepatocyte Model to Investigate Chemical Mode of Action

EPA Science Inventory

There is a clear need to identify and characterize the potential of liver in vitro models that can be used to replace animals for mode of action analysis. Our goal is to use in vitro models for mode of action prediction which recapitulate critical cellular processes underlying in...

Modeling Healthy Behavior: Actions and Attitudes in Schools.

ERIC Educational Resources Information Center

Berryman, Judy C.; Breighner, Kathryn W.

This book notes that much of what children and adolescents know about life they learn from watching adult role models: teachers, parents, coaches, and clergy members. It was written to help adults examine their health-related beliefs and actions and evaluate how they model these beliefs and actions, consciously and unconsciously, to children. The…

TESTING THE PROPAGATING FLUCTUATIONS MODEL WITH A LONG, GLOBAL ACCRETION DISK SIMULATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hogg, J Drew; Reynolds, Christopher S.

2016-07-20

The broadband variability of many accreting systems displays characteristic structures; log-normal flux distributions, root-mean square (rms)-flux relations, and long inter-band lags. These characteristics are usually interpreted as inward propagating fluctuations of the mass accretion rate in an accretion disk driven by stochasticity of the angular momentum transport mechanism. We present the first analysis of propagating fluctuations in a long-duration, high-resolution, global three-dimensional magnetohydrodynamic (MHD) simulation of a geometrically thin ( h / r ≈ 0.1) accretion disk around a black hole. While the dynamical-timescale turbulent fluctuations in the Maxwell stresses are too rapid to drive radially coherent fluctuations in themore » accretion rate, we find that the low-frequency quasi-periodic dynamo action introduces low-frequency fluctuations in the Maxwell stresses, which then drive the propagating fluctuations. Examining both the mass accretion rate and emission proxies, we recover log-normality, linear rms-flux relations, and radial coherence that would produce inter-band lags. Hence, we successfully relate and connect the phenomenology of propagating fluctuations to modern MHD accretion disk theory.« less

Planning for Bioterrorism. Behavioral & Mental Health Responses to Weapons of Mass Destruction & Mass Disruption

DTIC Science & Technology

2000-07-16

Specifically, the management of the acute situation will set the tone for societal responses. The accurate portrayal of ongoing efforts and successful...their comments and actions. Specifically, the management of the acute situation will set the tone for societal responses. The accurate portrayal of...casualties. In the acute phase, anxiolytics may help acutely anxious individuals who do not respond to reassurance and education. In the chronic phase

Chemical Safety Alert: First Responders’ Environmental Liability Due To Mass Decontamination Runoff

EPA Pesticide Factsheets

CERCLA's good Samaritan provisions protect responders such as the Chemical Weapons Improved Response Team during lifesaving actions. Once imminent threats are addressed, responders should contain contamination and avoid/mitigate environmental consequences.

Uncertainty in action-value estimation affects both action choice and learning rate of the choice behaviors of rats.

PubMed

Funamizu, Akihiro; Ito, Makoto; Doya, Kenji; Kanzaki, Ryohei; Takahashi, Hirokazu

2012-04-01

The estimation of reward outcomes for action candidates is essential for decision making. In this study, we examined whether and how the uncertainty in reward outcome estimation affects the action choice and learning rate. We designed a choice task in which rats selected either the left-poking or right-poking hole and received a reward of a food pellet stochastically. The reward probabilities of the left and right holes were chosen from six settings (high, 100% vs. 66%; mid, 66% vs. 33%; low, 33% vs. 0% for the left vs. right holes, and the opposites) in every 20-549 trials. We used Bayesian Q-learning models to estimate the time course of the probability distribution of action values and tested if they better explain the behaviors of rats than standard Q-learning models that estimate only the mean of action values. Model comparison by cross-validation revealed that a Bayesian Q-learning model with an asymmetric update for reward and non-reward outcomes fit the choice time course of the rats best. In the action-choice equation of the Bayesian Q-learning model, the estimated coefficient for the variance of action value was positive, meaning that rats were uncertainty seeking. Further analysis of the Bayesian Q-learning model suggested that the uncertainty facilitated the effective learning rate. These results suggest that the rats consider uncertainty in action-value estimation and that they have an uncertainty-seeking action policy and uncertainty-dependent modulation of the effective learning rate. © 2012 The Authors. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Simulation of action potential propagation in plants.

PubMed

Sukhov, Vladimir; Nerush, Vladimir; Orlova, Lyubov; Vodeneev, Vladimir

2011-12-21

Action potential is considered to be one of the primary responses of a plant to action of various environmental factors. Understanding plant action potential propagation mechanisms requires experimental investigation and simulation; however, a detailed mathematical model of plant electrical signal transmission is absent. Here, the mathematical model of action potential propagation in plants has been worked out. The model is a two-dimensional system of excitable cells; each of them is electrically coupled with four neighboring ones. Ion diffusion between excitable cell apoplast areas is also taken into account. The action potential generation in a single cell has been described on the basis of our previous model. The model simulates active and passive signal transmission well enough. It has been used to analyze theoretically the influence of cell to cell electrical conductivity and H(+)-ATPase activity on the signal transmission in plants. An increase in cell to cell electrical conductivity has been shown to stimulate an increase in the length constant, the action potential propagation velocity and the temperature threshold, while the membrane potential threshold being weakly changed. The growth of H(+)-ATPase activity has been found to induce the increase of temperature and membrane potential thresholds and the reduction of the length constant and the action potential propagation velocity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Action Recognition Using Nonnegative Action Component Representation and Sparse Basis Selection.

PubMed

Wang, Haoran; Yuan, Chunfeng; Hu, Weiming; Ling, Haibin; Yang, Wankou; Sun, Changyin

2014-02-01

In this paper, we propose using high-level action units to represent human actions in videos and, based on such units, a novel sparse model is developed for human action recognition. There are three interconnected components in our approach. First, we propose a new context-aware spatial-temporal descriptor, named locally weighted word context, to improve the discriminability of the traditionally used local spatial-temporal descriptors. Second, from the statistics of the context-aware descriptors, we learn action units using the graph regularized nonnegative matrix factorization, which leads to a part-based representation and encodes the geometrical information. These units effectively bridge the semantic gap in action recognition. Third, we propose a sparse model based on a joint l2,1-norm to preserve the representative items and suppress noise in the action units. Intuitively, when learning the dictionary for action representation, the sparse model captures the fact that actions from the same class share similar units. The proposed approach is evaluated on several publicly available data sets. The experimental results and analysis clearly demonstrate the effectiveness of the proposed approach.

Biological and behavioral factors modify urinary arsenic metabolic profiles in a U.S. population.

PubMed

Hudgens, Edward E; Drobna, Zuzana; He, Bin; Le, X C; Styblo, Miroslav; Rogers, John; Thomas, David J

2016-05-26

Because some adverse health effects associated with chronic arsenic exposure may be mediated by methylated arsenicals, interindividual variation in capacity to convert inorganic arsenic into mono- and di-methylated metabolites may be an important determinant of risk associated with exposure to this metalloid. Hence, identifying biological and behavioral factors that modify an individual's capacity to methylate inorganic arsenic could provide insights into critical dose-response relations underlying adverse health effects. A total of 904 older adults (≥45 years old) in Churchill County, Nevada, who chronically used home tap water supplies containing up to 1850 μg of arsenic per liter provided urine and toenail samples for determination of total and speciated arsenic levels. Effects of biological factors (gender, age, body mass index) and behavioral factors (smoking, recent fish or shellfish consumption) on patterns of arsenicals in urine were evaluated with bivariate analyses and multivariate regression models. Relative contributions of inorganic, mono-, and di-methylated arsenic to total speciated arsenic in urine were unchanged over the range of concentrations of arsenic in home tap water supplies used by study participants. Gender predicted both absolute and relative amounts of arsenicals in urine. Age predicted levels of inorganic arsenic in urine and body mass index predicted relative levels of mono- and di-methylated arsenic in urine. Smoking predicted both absolute and relative levels of arsenicals in urine. Multivariate regression models were developed for both absolute and relative levels of arsenicals in urine. Concentration of arsenic in home tap water and estimated water consumption were strongly predictive of levels of arsenicals in urine as were smoking, body mass index, and gender. Relative contributions of arsenicals to urinary arsenic were not consistently predicted by concentrations of arsenic in drinking water supplies but were more consistently predicted by gender, body mass index, age, and smoking. These findings suggest that analyses of dose-response relations in arsenic-exposed populations should account for biological and behavioral factors that modify levels of inorganic and methylated arsenicals in urine. Evidence of significant effects of these factors on arsenic metabolism may also support mode of action studies in appropriate experimental models.

An integrated theory of language production and comprehension.

PubMed

Pickering, Martin J; Garrod, Simon

2013-08-01

Currently, production and comprehension are regarded as quite distinct in accounts of language processing. In rejecting this dichotomy, we instead assert that producing and understanding are interwoven, and that this interweaving is what enables people to predict themselves and each other. We start by noting that production and comprehension are forms of action and action perception. We then consider the evidence for interweaving in action, action perception, and joint action, and explain such evidence in terms of prediction. Specifically, we assume that actors construct forward models of their actions before they execute those actions, and that perceivers of others' actions covertly imitate those actions, then construct forward models of those actions. We use these accounts of action, action perception, and joint action to develop accounts of production, comprehension, and interactive language. Importantly, they incorporate well-defined levels of linguistic representation (such as semantics, syntax, and phonology). We show (a) how speakers and comprehenders use covert imitation and forward modeling to make predictions at these levels of representation, (b) how they interweave production and comprehension processes, and (c) how they use these predictions to monitor the upcoming utterances. We show how these accounts explain a range of behavioral and neuroscientific data on language processing and discuss some of the implications of our proposal.

The Effect of Models, Reference Groups, and Social Responsibility Norms Upon Participation in Prosocial Action Activities

ERIC Educational Resources Information Center

Johnson, David W.; Neale, Daniel C.

1970-01-01

A sample of undergraduate students and members of a social action project did not differ on the Berkowitz and Daniels social responsibility scale. Participation in prosocial action is related to perceived reference group norms and to perceived exposure to prosocial action models both within and outside the family." (Author/DB)

Using a health-rating system to evaluate the usefulness of Caenorhabditis elegans as a model for anthelmintic study

PubMed Central

Weaver, Kathryn J.; May, Cassandra J.

2017-01-01

Soil-transmitted helminths (STHs) are intestinal parasitic nematodes that infect humans, and are transmitted through contaminated soil. These nematodes include the large roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), and hookworm (Ancylostoma ceylanicum, Ancylostoma duodenale, and Necator americanus). Nearly 1.5 billion people (~24% of the population) worldwide are infected with at least one species of these parasites, burdening the poor, in particular, children and pregnant women. To combat these diseases, the WHO only recognizes four anthelmintic drugs, including the preferred drug, albendazole, for mass drug administration (MDA). These four drugs have a total of two different mechanisms of action, and, as expected, resistance has been observed. This problem calls for new drugs with different mechanisms of action. Although there is precedence for the use of Caenorhabditis elegans (C. elegans), a free-living nematode, as a model for drug screening and anthelmintic testing, their usefulness for such anthelmintic study is not clear as past research has shown that C. elegans did not show a strong response to albendazole, the MDA drug of choice, in comparison with various STHs under similar treatment. To further examine if C. elegans has the potential to be a good model organism for anthelmintic drug study, we employed a health rating scale in order to tease out potential effects of albendazole, and other anthelmintics, that may have been missed using a binary, dead/alive scale. Using the health-rating scale we found that although the worms may have not been dying, they were sick, showing dose responses to anthelmintic drugs, including albendazole, reinforcing C. elegans as a useful model for anthelmintic study. PMID:28632749

2-D modelling and simulation of EM brake for liquid steel

NASA Astrophysics Data System (ADS)

Aslan, Necdet; Senturk, Kenan; Tessarotto, Massimo

2003-11-01

The problem of EM control of bottom tapping in steelmaking metallurgy is an old and well known challenge not only from the technological viewpoint but also, potentially, an interesting and still open theoretical problem, from the viewpoint of the investigation of the detailed MHD phenomena occurring in EM braking devices [1]. Purpose of the present work is the formulation of a 2-D MHD model for a DC EM braking device, which includes the consistent modelization of inductive EM fields produced by the conductive fluid, large scale turbulence, boundary conditions for the EM fields and thermal effects. The mathematical model has been implemented in a new 2-D MHD code developed for this purpose [2], based on the so-called fluctuation splitting and dual-time stepping methods, respectively, to advance in time the fluid fields and satisfy the relevant incompressibility-solenoidality conditions for the fluid mass velocity and the magnetic field. Main goal of the investigation is the analysis of the nonlinear phenomena occurring in the process of slowing down of a column of liquid steel under the action of the EM brake, and in particular the detailed description of the effects of large scale turbulence produced by the action of Lorentz force on the fluid, their influence on the magnitude of the inductive EM fields and the performance of the EM brake itself. REFERENCES [1] A.Codutti, A.Martinis, M.Pavlicevic, M.Tessarotto and D.Batic, Proc. 3rd International Symposium on EMP (Nagoya, Japan, April 2000), p.530 (2000). [2] N.Aslan, K.Senturk and M.Tessarotto, Efficient 2-D solver for incompressible magnefluids, communication at this Conference (2003).

Identification of the mechanism of action of a glucokinase activator from oral glucose tolerance test data in type 2 diabetic patients based on an integrated glucose-insulin model.

PubMed

Jauslin, Petra M; Karlsson, Mats O; Frey, Nicolas

2012-12-01

A mechanistic drug-disease model was developed on the basis of a previously published integrated glucose-insulin model by Jauslin et al. A glucokinase activator was used as a test compound to evaluate the model's ability to identify a drug's mechanism of action and estimate its effects on glucose and insulin profiles following oral glucose tolerance tests. A kinetic-pharmacodynamic approach was chosen to describe the drug's pharmacodynamic effects in a dose-response-time model. Four possible mechanisms of action of antidiabetic drugs were evaluated, and the corresponding affected model parameters were identified: insulin secretion, glucose production, insulin effect on glucose elimination, and insulin-independent glucose elimination. Inclusion of drug effects in the model at these sites of action was first tested one-by-one and then in combination. The results demonstrate the ability of this model to identify the dual mechanism of action of a glucokinase activator and describe and predict its effects: Estimating a stimulating drug effect on insulin secretion and an inhibiting effect on glucose output resulted in a significantly better model fit than any other combination of effect sites. The model may be used for dose finding in early clinical drug development and for gaining more insight into a drug candidate's mechanism of action.

Discrete-State Stochastic Models of Calcium-Regulated Calcium Influx and Subspace Dynamics Are Not Well-Approximated by ODEs That Neglect Concentration Fluctuations

PubMed Central

Weinberg, Seth H.; Smith, Gregory D.

2012-01-01

Cardiac myocyte calcium signaling is often modeled using deterministic ordinary differential equations (ODEs) and mass-action kinetics. However, spatially restricted “domains” associated with calcium influx are small enough (e.g., 10−17 liters) that local signaling may involve 1–100 calcium ions. Is it appropriate to model the dynamics of subspace calcium using deterministic ODEs or, alternatively, do we require stochastic descriptions that account for the fundamentally discrete nature of these local calcium signals? To address this question, we constructed a minimal Markov model of a calcium-regulated calcium channel and associated subspace. We compared the expected value of fluctuating subspace calcium concentration (a result that accounts for the small subspace volume) with the corresponding deterministic model (an approximation that assumes large system size). When subspace calcium did not regulate calcium influx, the deterministic and stochastic descriptions agreed. However, when calcium binding altered channel activity in the model, the continuous deterministic description often deviated significantly from the discrete stochastic model, unless the subspace volume is unrealistically large and/or the kinetics of the calcium binding are sufficiently fast. This principle was also demonstrated using a physiologically realistic model of calmodulin regulation of L-type calcium channels introduced by Yue and coworkers. PMID:23509597

Action-Oriented Research: Models and Methods.

ERIC Educational Resources Information Center

Small, Stephen A.

1995-01-01

Four models of action-oriented research, a research approach that can inform policy and practice, are described: action, participatory, empowerment, and feminism research. Discusses historical roots, epistemological assumptions, agendas, and methodological strategies of each, and presents implications for family researchers. (JPS)

A Functional Model of the Digital Extensor Mechanism: Demonstrating Biomechanics with Hair Bands

ERIC Educational Resources Information Center

Cloud, Beth A.; Youdas, James W.; Hellyer, Nathan J.; Krause, David A.

2010-01-01

The action of muscles about joints can be explained through analysis of their spatial relationship. A functional model of these relationships can be valuable in learning and understanding the muscular action about a joint. A model can be particularly helpful when examining complex actions across multiple joints such as in the digital extensor…

Effects of modeling errors on trajectory predictions in air traffic control automation

NASA Technical Reports Server (NTRS)

Jackson, Michael R. C.; Zhao, Yiyuan; Slattery, Rhonda

1996-01-01

Air traffic control automation synthesizes aircraft trajectories for the generation of advisories. Trajectory computation employs models of aircraft performances and weather conditions. In contrast, actual trajectories are flown in real aircraft under actual conditions. Since synthetic trajectories are used in landing scheduling and conflict probing, it is very important to understand the differences between computed trajectories and actual trajectories. This paper examines the effects of aircraft modeling errors on the accuracy of trajectory predictions in air traffic control automation. Three-dimensional point-mass aircraft equations of motion are assumed to be able to generate actual aircraft flight paths. Modeling errors are described as uncertain parameters or uncertain input functions. Pilot or autopilot feedback actions are expressed as equality constraints to satisfy control objectives. A typical trajectory is defined by a series of flight segments with different control objectives for each flight segment and conditions that define segment transitions. A constrained linearization approach is used to analyze trajectory differences caused by various modeling errors by developing a linear time varying system that describes the trajectory errors, with expressions to transfer the trajectory errors across moving segment transitions. A numerical example is presented for a complete commercial aircraft descent trajectory consisting of several flight segments.

Physician's Breakout Session

NASA Technical Reports Server (NTRS)

Barry, William

2001-01-01

Dr. William Barry, Manager, NASA Occupational Health Program, moderated this session. As in one of the opening sessions, he re-iterated that the overall theme for the next year will be facilitating and implementing NIAT-1 (NASA Integrated Action Team - Action 1). He presented a candidate list of topics for consideration and discussion: (1) NIAT-1; (2) Skin cancer detection and the NASA Solar Safe Program; (3) Weapons of mass destruction; (4) Quality assurance; (5) Audits; (6) Environment of care; (7) Infection control; (8) Medication management; and (9) Confidentiality of medical records.

A Parametric Computational Model of the Action Potential of Pacemaker Cells.

PubMed

Ai, Weiwei; Patel, Nitish D; Roop, Partha S; Malik, Avinash; Andalam, Sidharta; Yip, Eugene; Allen, Nathan; Trew, Mark L

2018-01-01

A flexible, efficient, and verifiable pacemaker cell model is essential to the design of real-time virtual hearts that can be used for closed-loop validation of cardiac devices. A new parametric model of pacemaker action potential is developed to address this need. The action potential phases are modeled using hybrid automaton with one piecewise-linear continuous variable. The model can capture rate-dependent dynamics, such as action potential duration restitution, conduction velocity restitution, and overdrive suppression by incorporating nonlinear update functions. Simulated dynamics of the model compared well with previous models and clinical data. The results show that the parametric model can reproduce the electrophysiological dynamics of a variety of pacemaker cells, such as sinoatrial node, atrioventricular node, and the His-Purkinje system, under varying cardiac conditions. This is an important contribution toward closed-loop validation of cardiac devices using real-time heart models.

Toward an integrated account of object and action selection: A computational analysis and empirical findings from reaching-to-grasp and tool-use

PubMed Central

Botvinick, Matthew M.; Buxbaum, Laurel J.; Bylsma, Lauren M.; Jax, Steven A.

2014-01-01

The act of reaching for and acting upon an object involves two forms of selection: selection of the object as a target, and selection of the action to be performed. While these two forms of selection are logically dissociable, and are evidently subserved by separable neural pathways, they must also be closely coordinated. We examine the nature of this coordination by developing and analyzing a computational model of object and action selection first proposed by Ward [Ward, R. (1999). Interactions between perception and action systems: a model for selective action. In G. W. Humphreys, J. Duncan, & A. Treisman (Eds.), Attention, Space and Action: Studies in Cognitive Neuroscience. Oxford: Oxford University Press]. An interesting tenet of this account, which we explore in detail, is that the interplay between object and action selection depends critically on top-down inputs representing the current task set or plan of action. A concrete manifestation of this, established through a series of simulations, is that the impact of distractor objects on reaching times can vary depending on the nature of the current action plan. In order to test the model's predictions in this regard, we conducted two experiments, one involving direct object manipulation, the other involving tool-use. In both experiments we observed the specific interaction between task set and distractor type predicted by the model. Our findings provide support for the computational model, and more broadly for an interactive account of object and action selection. PMID:19100758

Automated Interactive Simulation Model (AISIM) VAX Version 5.0 Training Manual.

DTIC Science & Technology

1987-05-29

action, activity, decision , etc. that consumes time. The entity is automatically created by the system when an ACTION Primitive is placed. 1.3.2.4 The...MODELED SYSTEM 1.3.2.1 The Process Entity. A Process is used to represent the operations, decisions , actions or activities that can be decomposed and...is associated with the Action entity described below, is included in Process definitions to indicate the time a certain Action (or process, decision

Mass Transit Intelligence Prioritization Act

THOMAS, 112th Congress

Rep. Speier, Jackie [D-CA-12

2011-10-06

Senate - 06/04/2012 Received in the Senate and Read twice and referred to the Committee on Homeland Security and Governmental Affairs. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

Equivalence principle implications of modified gravity models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hui, Lam; Nicolis, Alberto; Stubbs, Christopher W.

2009-11-15

Theories that attempt to explain the observed cosmic acceleration by modifying general relativity all introduce a new scalar degree of freedom that is active on large scales, but is screened on small scales to match experiments. We demonstrate that if such screening occurs via the chameleon mechanism, such as in f(R) theory, it is possible to have order unity violation of the equivalence principle, despite the absence of explicit violation in the microscopic action. Namely, extended objects such as galaxies or constituents thereof do not all fall at the same rate. The chameleon mechanism can screen the scalar charge formore » large objects but not for small ones (large/small is defined by the depth of the gravitational potential and is controlled by the scalar coupling). This leads to order one fluctuations in the ratio of the inertial mass to gravitational mass. We provide derivations in both Einstein and Jordan frames. In Jordan frame, it is no longer true that all objects move on geodesics; only unscreened ones, such as test particles, do. In contrast, if the scalar screening occurs via strong coupling, such as in the Dvali-Gabadadze-Porrati braneworld model, equivalence principle violation occurs at a much reduced level. We propose several observational tests of the chameleon mechanism: 1. small galaxies should accelerate faster than large galaxies, even in environments where dynamical friction is negligible; 2. voids defined by small galaxies would appear larger compared to standard expectations; 3. stars and diffuse gas in small galaxies should have different velocities, even if they are on the same orbits; 4. lensing and dynamical mass estimates should agree for large galaxies but disagree for small ones. We discuss possible pitfalls in some of these tests. The cleanest is the third one where the mass estimate from HI rotational velocity could exceed that from stars by 30% or more. To avoid blanket screening of all objects, the most promising place to look is in voids.« less

A network property necessary for concentration robustness

NASA Astrophysics Data System (ADS)

Eloundou-Mbebi, Jeanne M. O.; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

2016-10-01

Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications.

A network property necessary for concentration robustness.

PubMed

Eloundou-Mbebi, Jeanne M O; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

2016-10-19

Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications.

A network property necessary for concentration robustness

PubMed Central

Eloundou-Mbebi, Jeanne M. O.; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

2016-01-01

Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications. PMID:27759015

Nonlinear instability of half-solitons on star graphs

NASA Astrophysics Data System (ADS)

Kairzhan, Adilbek; Pelinovsky, Dmitry E.

2018-06-01

We consider a half-soliton stationary state of the nonlinear Schrödinger equation with the power nonlinearity on a star graph consisting of N edges and a single vertex. For the subcritical power nonlinearity, the half-soliton state is a degenerate critical point of the action functional under the mass constraint such that the second variation is nonnegative. By using normal forms, we prove that the degenerate critical point is a saddle point, for which the small perturbations to the half-soliton state grow slowly in time resulting in the nonlinear instability of the half-soliton state. The result holds for any N ≥ 3 and arbitrary subcritical power nonlinearity. It gives a precise dynamical characterization of the previous result of Adami et al. (2012) [2], where the half-soliton state was shown to be a saddle point of the action functional under the mass constraint for N = 3 and for cubic nonlinearity.

B -meson decay constants from 2 + 1 -flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

DOE PAGES

Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku; ...

2015-03-10

We calculate the B-meson decay constants f B, f Bs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as M π ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b quarks we use the anisotropic clovermore » action with the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(α sa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain f B0 = 199.5(12.6) MeV, f B+=195.6(14.9) MeV, f Bs=235.4(12.2) MeV, f Bs/f B0=1.197(50), and f Bs/f B+=1.223(71), where the errors are statistical and total systematic added in quadrature. Finally, these results are in good agreement with other published results and provide an important independent cross-check of other three-flavor determinations of B-meson decay constants using staggered light quarks.« less

B-meson decay constants from 2+1-flavor lattice QCD with domain-wall light quarks and relativistic heavy quarks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christ, Norman H.; Flynn, Jonathan M.; Izubuchi, Taku

2015-03-10

We calculate the B-meson decay constants f B, f Bs, and their ratio in unquenched lattice QCD using domain-wall light quarks and relativistic b-quarks. We use gauge-field ensembles generated by the RBC and UKQCD collaborations using the domain-wall fermion action and Iwasaki gauge action with three flavors of light dynamical quarks. We analyze data at two lattice spacings of a ≈ 0.11, 0.086 fm with unitary pion masses as light as M π ≈ 290 MeV; this enables us to control the extrapolation to the physical light-quark masses and continuum. For the b-quarks we use the anisotropic clover action withmore » the relativistic heavy-quark interpretation, such that discretization errors from the heavy-quark action are of the same size as from the light-quark sector. We renormalize the lattice heavy-light axial-vector current using a mostly nonperturbative method in which we compute the bulk of the matching factor nonperturbatively, with a small correction, that is close to unity, in lattice perturbation theory. We also improve the lattice heavy-light current through O(α sa). We extrapolate our results to the physical light-quark masses and continuum using SU(2) heavy-meson chiral perturbation theory, and provide a complete systematic error budget. We obtain f B0 = 196.2(15.7) MeV, f B+ = 195.4(15.8) MeV, f Bs = 235.4(12.2) MeV, f Bs/f B0 = 1.193(59), and f Bs/f B+ = 1.220(82), where the errors are statistical and total systematic added in quadrature. In addition, these results are in good agreement with other published results and provide an important independent cross check of other three-flavor determinations of B-meson decay constants using staggered light quarks.« less

NMR and molecular modeling: application to wine ageing

NASA Astrophysics Data System (ADS)

Saucier, C.; Pianet, I.; Laguerre, M.; Glories, Y.

1998-02-01

Red wine contains polyphenols called tannins which are very important for its taste and longevity. These polymers consist in repeating units of catechin and its epimer epicatechin. During ageing, slow condensation reactions take place which lead to new chemical structures. Among the possible reactions, we have focused our attention on acetaldehyde cross-linking. Catechin was used as a model for the production of polymers with acetaldehyde. Two reaction product fractions have been isolated by liquid chromatography. Mass measurement indicated that these fractions contain dimers. NMR (1D and 2D) and molecular modelling were then used to study the structure and conformations of these products. The first product consist in a pure dimer with the two catechin moieties connected with an ethyl bridge on the carbon 6 and 8. The second fraction was a mixture of two dimers (50/50). NMR measurements showed that it could be two symmetrical dimers involving the same carbon for each catechin moiety (6 or8). Le vin rouge contient des polyphénols appelés tanins qui sont très importants pour son goût et sa longévité. Il s'agit principalement de polymères de catéchine et d'épicatéchine. Durant le vieillissement du vin, des réactions de condensation interviennent lentement et conduisent à de nouvelles structures. Parmi les réactions possibles, nous avons plus spécialement étudié la polymérisation par pontage avec l'éthanal. La catéchine a été utilisée comme modèle de tannin et mise en présence d'éthanal en milieu acide proche du vin. Deux fractions de produits de réaction ont été isolées par chromatographie liquide. La spectrométrie de masse a révélé la présence de dimères. La RMN (1D et 2D) et la modélisation moléculaire ont ensuite été utilisées pour déterminer la structure et la conformation de ces produits. La première fraction a été identifiée comme étant un dimère de deux unités catéchines reliées par un pont éthyle par leur carbones6 et8. La seconde fraction isolée est un mélange de deux dimères (50/50). Les mesures RMN montrent qu'il pourrait s'agir de dimères symétriques reliés par le même carbone (6-6 et 8-8).

Insulin Action in Brain Regulates Systemic Metabolism and Brain Function

PubMed Central

Kleinridders, André; Ferris, Heather A.; Cai, Weikang

2014-01-01

Insulin receptors, as well as IGF-1 receptors and their postreceptor signaling partners, are distributed throughout the brain. Insulin acts on these receptors to modulate peripheral metabolism, including regulation of appetite, reproductive function, body temperature, white fat mass, hepatic glucose output, and response to hypoglycemia. Insulin signaling also modulates neurotransmitter channel activity, brain cholesterol synthesis, and mitochondrial function. Disruption of insulin action in the brain leads to impairment of neuronal function and synaptogenesis. In addition, insulin signaling modulates phosphorylation of tau protein, an early component in the development of Alzheimer disease. Thus, alterations in insulin action in the brain can contribute to metabolic syndrome, and the development of mood disorders and neurodegenerative diseases. PMID:24931034

Proactive action preparation: seeing action preparation as a continuous and proactive process.

PubMed

Pezzulo, Giovanni; Ognibene, Dimitri

2012-07-01

In this paper, we aim to elucidate the processes that occur during action preparation from both a conceptual and a computational point of view. We first introduce the traditional, serial model of goal-directed action and discuss from a computational viewpoint its subprocesses occurring during the two phases of covert action preparation and overt motor control. Then, we discuss recent evidence indicating that these subprocesses are highly intertwined at representational and neural levels, which undermines the validity of the serial model and points instead to a parallel model of action specification and selection. Within the parallel view, we analyze the case of delayed choice, arguing that action preparation can be proactive, and preparatory processes can take place even before decisions are made. Specifically, we discuss how prior knowledge and prospective abilities can be used to maximize utility even before deciding what to do. To support our view, we present a computational implementation of (an approximated version of) proactive action preparation, showing its advantages in a simulated tennis-like scenario.

Hadron spectroscopy with dynamical chirally improved fermions

NASA Astrophysics Data System (ADS)

Gattringer, Christof; Hagen, Christian; Lang, C. B.; Limmer, Markus; Mohler, Daniel; Schäfer, Andreas

2009-03-01

We simulate two dynamical, mass-degenerate light quarks on 163×32 lattices with a spatial extent of 2.4 fm using the chirally improved Dirac operator. The simulation method, the implementation of the action, and signals of equilibration are discussed in detail. Based on the eigenvalues of the Dirac operator we discuss some qualitative features of our approach. Results for ground-state masses of pseudoscalar and vector mesons as well as for the nucleon and delta baryons are presented.

Perception-action dissociation generalizes to the size-inertia illusion.

PubMed

Platkiewicz, Jonathan; Hayward, Vincent

2014-04-01

Two objects of similar visual aspects and of equal mass, but of different sizes, generally do not elicit the same percept of heaviness in humans. The larger object is consistently felt to be lighter than the smaller, an effect known as the "size-weight illusion." When asked to repeatedly lift the two objects, the grip forces were observed to adapt rapidly to the true object weight while the size-weight illusion persisted, a phenomenon interpreted as a dissociation between perception and action. We investigated whether the same phenomenon can be observed if the mass of an object is available to participants through inertial rather than gravitational cues and if the number and statistics of the stimuli is such that participants cannot remember each individual stimulus. We compared the responses of 10 participants in 2 experimental conditions, where they manipulated 33 objects having uncorrelated masses and sizes, supported by a frictionless, air-bearing slide that could be oriented vertically or horizontally. We also analyzed the participants' anticipatory motor behavior by measuring the grip force before motion onset. We found that the perceptual illusory effect was quantitatively the same in the two conditions and observed that both visual size and haptic mass had a negligible effect on the anticipatory gripping control of the participants in the gravitational and inertial conditions, despite the enormous differences in the mechanics of the two conditions and the large set of uncorrelated stimuli.

The Complex Action Recognition via the Correlated Topic Model

PubMed Central

Tu, Hong-bin; Xia, Li-min; Wang, Zheng-wu

2014-01-01

Human complex action recognition is an important research area of the action recognition. Among various obstacles to human complex action recognition, one of the most challenging is to deal with self-occlusion, where one body part occludes another one. This paper presents a new method of human complex action recognition, which is based on optical flow and correlated topic model (CTM). Firstly, the Markov random field was used to represent the occlusion relationship between human body parts in terms of an occlusion state variable. Secondly, the structure from motion (SFM) is used for reconstructing the missing data of point trajectories. Then, we can extract the key frame based on motion feature from optical flow and the ratios of the width and height are extracted by the human silhouette. Finally, we use the topic model of correlated topic model (CTM) to classify action. Experiments were performed on the KTH, Weizmann, and UIUC action dataset to test and evaluate the proposed method. The compared experiment results showed that the proposed method was more effective than compared methods. PMID:24574920

Corrective Action Decision Document/Corrective Action Plan for Corrective Action Unit 97: Yucca Flat/Climax Mine Nevada National Security Site, Nevada, Revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farnham, Irene

This corrective action decision document (CADD)/corrective action plan (CAP) has been prepared for Corrective Action Unit (CAU) 97, Yucca Flat/Climax Mine, Nevada National Security Site (NNSS), Nevada. The Yucca Flat/Climax Mine CAU is located in the northeastern portion of the NNSS and comprises 720 corrective action sites. A total of 747 underground nuclear detonations took place within this CAU between 1957 and 1992 and resulted in the release of radionuclides (RNs) in the subsurface in the vicinity of the test cavities. The CADD portion describes the Yucca Flat/Climax Mine CAU data-collection and modeling activities completed during the corrective action investigationmore » (CAI) stage, presents the corrective action objectives, and describes the actions recommended to meet the objectives. The CAP portion describes the corrective action implementation plan. The CAP presents CAU regulatory boundary objectives and initial use-restriction boundaries identified and negotiated by DOE and the Nevada Division of Environmental Protection (NDEP). The CAP also presents the model evaluation process designed to build confidence that the groundwater flow and contaminant transport modeling results can be used for the regulatory decisions required for CAU closure. The UGTA strategy assumes that active remediation of subsurface RN contamination is not feasible with current technology. As a result, the corrective action is based on a combination of characterization and modeling studies, monitoring, and institutional controls. The strategy is implemented through a four-stage approach that comprises the following: (1) corrective action investigation plan (CAIP), (2) CAI, (3) CADD/CAP, and (4) closure report (CR) stages.« less

Using process algebra to develop predator-prey models of within-host parasite dynamics.

PubMed

McCaig, Chris; Fenton, Andy; Graham, Andrea; Shankland, Carron; Norman, Rachel

2013-07-21

As a first approximation of immune-mediated within-host parasite dynamics we can consider the immune response as a predator, with the parasite as its prey. In the ecological literature of predator-prey interactions there are a number of different functional responses used to describe how a predator reproduces in response to consuming prey. Until recently most of the models of the immune system that have taken a predator-prey approach have used simple mass action dynamics to capture the interaction between the immune response and the parasite. More recently Fenton and Perkins (2010) employed three of the most commonly used prey-dependent functional response terms from the ecological literature. In this paper we make use of a technique from computing science, process algebra, to develop mathematical models. The novelty of the process algebra approach is to allow stochastic models of the population (parasite and immune cells) to be developed from rules of individual cell behaviour. By using this approach in which individual cellular behaviour is captured we have derived a ratio-dependent response similar to that seen in the previous models of immune-mediated parasite dynamics, confirming that, whilst this type of term is controversial in ecological predator-prey models, it is appropriate for models of the immune system. Copyright © 2013 Elsevier Ltd. All rights reserved.

HiTEC: a connectionist model of the interaction between perception and action planning.

PubMed

Haazebroek, Pascal; Raffone, Antonino; Hommel, Bernhard

2017-11-01

Increasing evidence suggests that perception and action planning do not represent separable stages of a unidirectional processing sequence, but rather emerging properties of highly interactive processes. To capture these characteristics of the human cognitive system, we have developed a connectionist model of the interaction between perception and action planning: HiTEC, based on the Theory of Event Coding (Hommel et al. in Behav Brain Sci 24:849-937, 2001). The model is characterized by representations at multiple levels and by shared representations and processes. It complements available models of stimulus-response translation by providing a rationale for (1) how situation-specific meanings of motor actions emerge, (2) how and why some aspects of stimulus-response translation occur automatically and (3) how task demands modulate sensorimotor processing. The model is demonstrated to provide a unitary account and simulation of a number of key findings with multiple experimental paradigms on the interaction between perception and action such as the Simon effect, its inversion (Hommel in Psychol Res 55:270-279, 1993), and action-effect learning.

"Should I or shouldn't I?" Imitation of undesired versus allowed actions from peer and adult models by 18- and 24-month-old toddlers.

PubMed

Seehagen, Sabine; Schneider, Silvia; Miebach, Kristin; Frigge, Katharina; Zmyj, Norbert

2017-11-01

Imitation is a common way of acquiring novel behaviors in toddlers. However, little is known about toddlers' imitation of undesired actions. Here we investigated 18- and 24-month-olds' (N=110) imitation of undesired and allowed actions from televised peer and adult models. Permissiveness of the demonstrated actions was indicated by the experimenter's response to their execution (angry or neutral). Analyses revealed that toddlers' imitation scores were higher after demonstrations of allowed versus undesired actions, regardless of the age of the model. In agreement with prior research, these results suggest that third-party reactions to a model's actions can be a powerful cue for toddlers to engage in or refrain from imitation. In the context of the present study, third-party reactions were more influential on imitation than the model's age. Considering the relative influence of different social cues for imitation can help to gain a fuller understanding of early observational learning. Copyright © 2017 Elsevier Inc. All rights reserved.

Neuronal correlates of decisions to speak and act: Spontaneous emergence and dynamic topographies in a computational model of frontal and temporal areas

PubMed Central

Garagnani, Max; Pulvermüller, Friedemann

2013-01-01

The neural mechanisms underlying the spontaneous, stimulus-independent emergence of intentions and decisions to act are poorly understood. Using a neurobiologically realistic model of frontal and temporal areas of the brain, we simulated the learning of perception–action circuits for speech and hand-related actions and subsequently observed their spontaneous behaviour. Noise-driven accumulation of reverberant activity in these circuits leads to their spontaneous ignition and partial-to-full activation, which we interpret, respectively, as model correlates of action intention emergence and action decision-and-execution. Importantly, activity emerged first in higher-association prefrontal and temporal cortices, subsequently spreading to secondary and finally primary sensorimotor model-areas, hence reproducing the dynamics of cortical correlates of voluntary action revealed by readiness-potential and verb-generation experiments. This model for the first time explains the cortical origins and topography of endogenous action decisions, and the natural emergence of functional specialisation in the cortex, as mechanistic consequences of neurobiological principles, anatomical structure and sensorimotor experience. PMID:23489583

Ursodeoxycholic acid and lithocholic acid exert anti-inflammatory actions in the colon.

PubMed

Ward, Joseph B J; Lajczak, Natalia K; Kelly, Orlaith B; O'Dwyer, Aoife M; Giddam, Ashwini K; Ní Gabhann, Joan; Franco, Placido; Tambuwala, Murtaza M; Jefferies, Caroline A; Keely, Simon; Roda, Aldo; Keely, Stephen J

2017-06-01

Ward JB, Lajczak NK, Kelly OB, O'Dwyer AM, Giddam AK, Ní Gabhann J, Franco P, Tambuwala MM, Jefferies CA, Keely S, Roda A, Keely SJ. Ursodeoxycholic acid and lithocholic acid exert anti-inflammatory actions in the colon. Am J Physiol Gastrointest Liver Physiol 312: G550-G558, 2017. First published March 30, 2017; doi:10.1152/ajpgi.00256.2016.-Inflammatory bowel diseases (IBD) comprise a group of common and debilitating chronic intestinal disorders for which currently available therapies are often unsatisfactory. The naturally occurring secondary bile acid, ursodeoxycholic acid (UDCA), has well-established anti-inflammatory and cytoprotective actions and may therefore be effective in treating IBD. We aimed to investigate regulation of colonic inflammatory responses by UDCA and to determine the potential impact of bacterial metabolism on its therapeutic actions. The anti-inflammatory efficacy of UDCA, a nonmetabolizable analog, 6α-methyl-UDCA (6-MUDCA), and its primary colonic metabolite lithocholic acid (LCA) was assessed in the murine dextran sodium sulfate (DSS) model of mucosal injury. The effects of bile acids on cytokine (TNF-α, IL-6, Il-1β, and IFN-γ) release from cultured colonic epithelial cells and mouse colonic tissue in vivo were investigated. Luminal bile acids were measured by gas chromatography-mass spectrometry. UDCA attenuated release of proinflammatory cytokines from colonic epithelial cells in vitro and was protective against the development of colonic inflammation in vivo. In contrast, although 6-MUDCA mimicked the effects of UDCA on epithelial cytokine release in vitro, it was ineffective in preventing inflammation in the DSS model. In UDCA-treated mice, LCA became the most common colonic bile acid. Finally, LCA treatment more potently inhibited epithelial cytokine release and protected against DSS-induced mucosal inflammation than did UDCA. These studies identify a new role for the primary metabolite of UDCA, LCA, in preventing colonic inflammation and suggest that microbial metabolism of UDCA is necessary for the full expression of its protective actions. NEW & NOTEWORTHY On the basis of its cytoprotective and anti-inflammatory actions, the secondary bile acid ursodeoxycholic acid (UDCA) has well-established uses in both traditional and Western medicine. We identify a new role for the primary metabolite of UDCA, lithocholic acid, as a potent inhibitor of intestinal inflammatory responses, and we present data to suggest that microbial metabolism of UDCA is necessary for the full expression of its protective effects against colonic inflammation. Copyright © 2017 the American Physiological Society.

Landquake dynamics inferred from seismic source inversion: Greenland and Sichuan events of 2017

NASA Astrophysics Data System (ADS)

Chao, W. A.

2017-12-01

In June 2017 two catastrophic landquake events occurred in Greenland and Sichuan. The Greenland event leads to tsunami hazard in the small town of Nuugaarsiaq. A landquake in Sichuan hit the town, which resulted in over 100 death. Both two events generated the strong seismic signals recorded by the real-time global seismic network. I adopt an inversion algorithm to derive the landquake force time history (LFH) using the long-period waveforms, and the landslide volume ( 76 million m3) can be rapidly estimated, facilitating the tsunami-wave modeling for early warning purpose. Based on an integrated approach involving tsunami forward simulation and seismic waveform inversion, this study has significant implications to issuing actionable warnings before hazardous tsunami waves strike populated areas. Two single-forces (SFs) mechanism (two block model) yields the best explanation for Sichuan event, which demonstrates that secondary event (seismic inferred volume: 8.2 million m3) may be mobilized by collapse-mass hitting from initial rock avalanches ( 5.8 million m3), likely causing a catastrophic disaster. The later source with a force magnitude of 0.9967×1011 N occurred 70 seconds after first mass-movement occurrence. In contrast, first event has the smaller force magnitude of 0.8116×1011 N. In conclusion, seismically inferred physical parameters will substantially contribute to improving our understanding of landquake source mechanisms and mitigating similar hazards in other parts of the world.

The energetics of AGN radiation pressure-driven outflows

NASA Astrophysics Data System (ADS)

Ishibashi, W.; Fabian, A. C.; Maiolino, R.

2018-05-01

The increasing observational evidence of galactic outflows is considered as a sign of active galactic nucleus (AGN) feedback in action. However, the physical mechanism responsible for driving the observed outflows remains unclear, and whether it is due to momentum, energy, or radiation is still a matter of debate. The observed outflow energetics, in particular the large measured values of the momentum ratio (\\dot{p}/(L/c) ˜ 10) and energy ratio (\\dot{E}_k/L ˜ 0.05), seems to favour the energy-driving mechanism; and most observational works have focused their comparison with wind energy-driven models. Here, we show that AGN radiation pressure on dust can adequately reproduce the observed outflow energetics (mass outflow rate, momentum flux, and kinetic power), as well as the scalings with luminosity, provided that the effects of radiation trapping are properly taken into account. In particular, we predict a sublinear scaling for the mass outflow rate (\\dot{M} ∝ L^{1/2}) and a superlinear scaling for the kinetic power (\\dot{E}_k ∝ L^{3/2}), in agreement with the observational scaling relations reported in the most recent compilation of AGN outflow data. We conclude that AGN radiative feedback can account for the global outflow energetics, at least equally well as the wind energy-driving mechanism, and therefore both physical models should be considered in the interpretation of future AGN outflow observations.

A quasi-molecular dynamics simulation study on the effect of particles collisions in pulsed-laser desorption

NASA Astrophysics Data System (ADS)

Xinyu-Tan; Duanming-Zhang; Shengqin-Feng; Li, Zhi-hua; Li, Guan; Li, Li; Dan, Liu

2006-05-01

The dynamics characteristic and effect of atoms and particulates ejected from the surface generated by nanosecond pulsed-laser ablation are very important. In this work, based on the consideration of the inelasticity and non-uniformity of the plasma particles thermally desorbed from a plane surface into vacuum induced by nanosecond laser ablation, the one-dimensional particles flow is studied on the basis of a quasi-molecular dynamics (QMD) simulation. It is assumed that atoms and particulates ejected from the surface of a target have a Maxwell velocity distribution corresponding to the surface temperature. Particles collisions in the ablation plume. The particles mass is continuous and satisfies fractal theory distribution. Meanwhile, the particles are inelastic. Our results show that inelasticity and non-uniformity strongly affect the dynamics behavior of the particles flow. Along with the decrease of restitution coefficient e and increase of fractional dimension D, velocity distributions of plasma particles system all deviate from the initial Gaussian distribution. The increasing of dissipation energy ΔE leads to density distribution clusterized and closed up to the center mass. Predictions of the particles action based on the proposed fractal and inelasticity model are found to be in agreement with the experimental observation. This verifies the validity of the present model for the dynamics behavior of pulsed-laser-induced particles flow.

Population of computational rabbit-specific ventricular action potential models for investigating sources of variability in cellular repolarisation.

PubMed

Gemmell, Philip; Burrage, Kevin; Rodriguez, Blanca; Quinn, T Alexander

2014-01-01

Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K(+), inward rectifying K(+), L-type Ca(2+), and Na(+)/K(+) pump currents) in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al.) at multiple cycle lengths (400, 600, 1,000 ms) was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in experimentally observed intercellular variability of rabbit ventricular action potential repolarisation.

Population of Computational Rabbit-Specific Ventricular Action Potential Models for Investigating Sources of Variability in Cellular Repolarisation

PubMed Central

Gemmell, Philip; Burrage, Kevin; Rodriguez, Blanca; Quinn, T. Alexander

2014-01-01

Variability is observed at all levels of cardiac electrophysiology. Yet, the underlying causes and importance of this variability are generally unknown, and difficult to investigate with current experimental techniques. The aim of the present study was to generate populations of computational ventricular action potential models that reproduce experimentally observed intercellular variability of repolarisation (represented by action potential duration) and to identify its potential causes. A systematic exploration of the effects of simultaneously varying the magnitude of six transmembrane current conductances (transient outward, rapid and slow delayed rectifier K+, inward rectifying K+, L-type Ca2+, and Na+/K+ pump currents) in two rabbit-specific ventricular action potential models (Shannon et al. and Mahajan et al.) at multiple cycle lengths (400, 600, 1,000 ms) was performed. This was accomplished with distributed computing software specialised for multi-dimensional parameter sweeps and grid execution. An initial population of 15,625 parameter sets was generated for both models at each cycle length. Action potential durations of these populations were compared to experimentally derived ranges for rabbit ventricular myocytes. 1,352 parameter sets for the Shannon model and 779 parameter sets for the Mahajan model yielded action potential duration within the experimental range, demonstrating that a wide array of ionic conductance values can be used to simulate a physiological rabbit ventricular action potential. Furthermore, by using clutter-based dimension reordering, a technique that allows visualisation of multi-dimensional spaces in two dimensions, the interaction of current conductances and their relative importance to the ventricular action potential at different cycle lengths were revealed. Overall, this work represents an important step towards a better understanding of the role that variability in current conductances may play in experimentally observed intercellular variability of rabbit ventricular action potential repolarisation. PMID:24587229

The robust corrective action priority-an improved approach for selecting competing corrective actions in FMEA based on principle of robust design

NASA Astrophysics Data System (ADS)

Sutrisno, Agung; Gunawan, Indra; Vanany, Iwan

2017-11-01

In spite of being integral part in risk - based quality improvement effort, studies improving quality of selection of corrective action priority using FMEA technique are still limited in literature. If any, none is considering robustness and risk in selecting competing improvement initiatives. This study proposed a theoretical model to select risk - based competing corrective action by considering robustness and risk of competing corrective actions. We incorporated the principle of robust design in counting the preference score among corrective action candidates. Along with considering cost and benefit of competing corrective actions, we also incorporate the risk and robustness of corrective actions. An example is provided to represent the applicability of the proposed model.

Modeling Composite Laminate Crushing for Crash Analysis

NASA Technical Reports Server (NTRS)

Fleming, David C.; Jones, Lisa (Technical Monitor)

2002-01-01

Crash modeling of composite structures remains limited in application and has not been effectively demonstrated as a predictive tool. While the global response of composite structures may be well modeled, when composite structures act as energy-absorbing members through direct laminate crushing the modeling accuracy is greatly reduced. The most efficient composite energy absorbing structures, in terms of energy absorbed per unit mass, are those that absorb energy through a complex progressive crushing response in which fiber and matrix fractures on a small scale dominate the behavior. Such failure modes simultaneously include delamination of plies, failure of the matrix to produce fiber bundles, and subsequent failure of fiber bundles either in bending or in shear. In addition, the response may include the significant action of friction, both internally (between delaminated plies or fiber bundles) or externally (between the laminate and the crushing surface). A figure shows the crushing damage observed in a fiberglass composite tube specimen, illustrating the complexity of the response. To achieve a finite element model of such complex behavior is an extremely challenging problem. A practical crushing model based on detailed modeling of the physical mechanisms of crushing behavior is not expected in the foreseeable future. The present research describes attempts to model composite crushing behavior using a novel hybrid modeling procedure. Experimental testing is done is support of the modeling efforts, and a test specimen is developed to provide data for validating laminate crushing models.

The anesthetic action of some polyhalogenated ethers-Monte Carlo method based QSAR study.

PubMed

Golubović, Mlađan; Lazarević, Milan; Zlatanović, Dragan; Krtinić, Dane; Stoičkov, Viktor; Mladenović, Bojan; Milić, Dragan J; Sokolović, Dušan; Veselinović, Aleksandar M

2018-04-13

Up to this date, there has been an ongoing debate about the mode of action of general anesthetics, which have postulated many biological sites as targets for their action. However, postoperative nausea and vomiting are common problems in which inhalational agents may have a role in their development. When a mode of action is unknown, QSAR modelling is essential in drug development. To investigate the aspects of their anesthetic, QSAR models based on the Monte Carlo method were developed for a set of polyhalogenated ethers. Until now, their anesthetic action has not been completely defined, although some hypotheses have been suggested. Therefore, a QSAR model should be developed on molecular fragments that contribute to anesthetic action. QSAR models were built on the basis of optimal molecular descriptors based on the SMILES notation and local graph invariants, whereas the Monte Carlo optimization method with three random splits into the training and test set was applied for model development. Different methods, including novel Index of ideality correlation, were applied for the determination of the robustness of the model and its predictive potential. The Monte Carlo optimization process was capable of being an efficient in silico tool for building up a robust model of good statistical quality. Molecular fragments which have both positive and negative influence on anesthetic action were determined. The presented study can be useful in the search for novel anesthetics. Copyright © 2018 Elsevier Ltd. All rights reserved.

Androgen signaling in myocytes contributes to the maintenance of muscle mass and fiber type regulation but not to muscle strength or fatigue.

PubMed

Ophoff, Jill; Van Proeyen, Karen; Callewaert, Filip; De Gendt, Karel; De Bock, Katrien; Vanden Bosch, An; Verhoeven, Guido; Hespel, Peter; Vanderschueren, Dirk

2009-08-01

Muscle frailty is considered a major cause of disability in the elderly and chronically ill. However, the exact role of androgen receptor (AR) signaling in muscle remains unclear. Therefore, a postmitotic myocyte-specific AR knockout (mARKO) mouse model was created and investigated together with a mouse model with ubiquitous AR deletion. Muscles from mARKO mice displayed a marked reduction in AR protein (60-88%). Interestingly, body weights and lean body mass were lower in mARKO vs. control mice (-8%). The weight of the highly androgen-sensitive musculus levator ani was significantly reduced (-46%), whereas the weights of other peripheral skeletal muscles were not or only slightly reduced. mARKO mice had lower intra-abdominal fat but did not demonstrate a cortical or trabecular bone phenotype, indicating that selective ablation of the AR in myocytes affected male body composition but not skeletal homeostasis. Furthermore, muscle contractile performance in mARKO mice did not differ from their controls. Myocyte-specific AR ablation resulted in a conversion of fast toward slow fibers, without affecting muscle strength or fatigue. Similar results were obtained in ubiquitous AR deletion, showing lower body weight, whereas some but not all muscle weights were reduced. The percent slow fibers was increased, but no changes in muscle strength or fatigue could be detected. Together, our findings show that myocyte AR signaling contributes to the maintenance of muscle mass and fiber type regulation but not to muscle strength or fatigue. The levator ani weight remains the most sensitive and specific marker of AR-mediated anabolic action on muscle.

Abrupt global events in the Earth's history: a physics perspective

NASA Astrophysics Data System (ADS)

Ryskin, Gregory

2010-12-01

The timeline of the Earth's history reveals quasi-periodicity of the geological record over the last 542 Myr, on timescales close, in the order of magnitude, to 1 Myr. What is the origin of this quasi-periodicity? What is the nature of the global events that define the boundaries of the geological time scale? I propose that a single mechanism is responsible for all three types of such events: mass extinctions, geomagnetic polarity reversals, and sea-level fluctuations. The mechanism is fast, and involves a significant energy release. The mechanism is unlikely to have astronomical causes, both because of the energies involved and because it acts quasi-periodically. It must then be sought within the Earth itself. And it must be capable of reversing the Earth's magnetic field. The last requirement makes it incompatible with the consensus model of the origin of the geomagnetic field—the hydromagnetic dynamo operating in the Earth's fluid core. In the second part of the paper, I show that a vast amount of seemingly unconnected geophysical and geological data can be understood in a unified way if the source of the Earth's main magnetic field is a ~200 km thick lithosphere, repeatedly magnetized as a result of methane-driven oceanic eruptions, which produce ocean flow capable of dynamo action. The eruptions are driven by the interplay of buoyancy forces and exsolution of dissolved gas, which accumulates in the oceanic water masses prone to stagnation and anoxia. Polarity reversals, mass extinctions and sequence boundaries are consequences of these eruptions. Unlike the consensus model of geomagnetism, this scenario is consistent with the paleomagnetic data showing that 'directional changes during a reversal can be astonishingly fast, possibly occurring as a nearly instantaneous jump from one inclined dipolar state to another in the opposite hemisphere'.